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Sample records for geothermal heat flux

  1. Organization of ice flow by localized regions of elevated geothermal heat flux

    NASA Astrophysics Data System (ADS)

    Pittard, M. L.; Galton-Fenzi, B. K.; Roberts, J. L.; Watson, C. S.

    2016-04-01

    The impact of localized regions of elevated geothermal heat flux on ice sheet dynamics is largely unknown. Simulations of ice dynamics are produced using poorly resolved and low-resolution estimates of geothermal heat flux. Observations of crustal heat production within the continental crust underneath the Lambert-Amery glacial system in East Antarctica indicate that high heat flux regions of at least 120 mW m-2 exist. Here we investigate the influence of simulated but plausible, localized regions of elevated geothermal heat flux on ice dynamics using a numerical ice sheet model of the Lambert-Amery glacial system. We find that high heat flux regions have a significant effect across areas of slow-moving ice with the influence extending both upstream and downstream of the geothermal anomaly, while fast-moving ice is relatively unaffected. Our results suggest that localized regions of elevated geothermal heat flux may play an important role in the organization of ice sheet flow.

  2. Estimating Antarctic Geothermal Heat Flux using Gravity Inversion

    NASA Astrophysics Data System (ADS)

    Vaughan, Alan P. M.; Kusznir, Nick J.; Ferraccioli, Fausto; Leat, Phil T.; Jordan, Tom A. R. M.; Purucker, Michael E.; Golynsky, A. V.; Sasha Rogozhina, Irina

    2013-04-01

    Geothermal heat flux (GHF) in Antarctica is very poorly known. We have determined (Vaughan et al. 2012) top basement heat-flow for Antarctica and adjacent rifted continental margins using gravity inversion mapping of crustal thickness and continental lithosphere thinning (Chappell & Kusznir 2008). Continental lithosphere thinning and post-breakup residual thicknesses of continental crust determined from gravity inversion have been used to predict the preservation of continental crustal radiogenic heat productivity and the transient lithosphere heat-flow contribution within thermally equilibrating rifted continental and oceanic lithosphere. The sensitivity of present-day Antarctic top basement heat-flow to initial continental radiogenic heat productivity, continental rift and margin breakup age has been examined. Knowing GHF distribution for East Antarctica and the Gamburtsev Subglacial Mountains (GSM) region in particular is critical because: 1) The GSM likely acted as key nucleation point for the East Antarctic Ice Sheet (EAIS); 2) the region may contain the oldest ice of the EAIS - a prime target for future ice core drilling; 3) GHF is important to understand proposed ice accretion at the base of the EAIS in the GSM and its links to sub-ice hydrology (Bell et al. 2011). An integrated multi-dataset-based GHF model for East Antarctica is planned that will resolve the wide range of estimates previously published using single datasets. The new map and existing GHF distribution estimates available for Antarctica will be evaluated using direct ice temperature measurements obtained from deep ice cores, estimates of GHF derived from subglacial lakes, and a thermodynamic ice-sheet model of the Antarctic Ice Sheet driven by past climate reconstructions and each of analysed heat flow maps, as has recently been done for the Greenland region (Rogozhina et al. 2012). References Bell, R.E., Ferraccioli, F., Creyts, T.T., Braaten, D., Corr, H., Das, I., Damaske, D., Frearson, N

  3. Using Gravity Inversion to Estimate Antarctic Geothermal Heat Flux

    NASA Astrophysics Data System (ADS)

    Vaughan, Alan P. M.; Kusznir, Nick J.; Ferraccioli, Fausto; Leat, Phil T.; Jordan, Tom A. R. M.; Purucker, Michael E.; (Sasha) Golynsky, A. V.; Rogozhina, Irina

    2014-05-01

    New modelling studies for Greenland have recently underlined the importance of GHF for long-term ice sheet behaviour (Petrunin et al. 2013). Revised determinations of top basement heat-flow for Antarctica and adjacent rifted continental margins using gravity inversion mapping of crustal thickness and continental lithosphere thinning (Chappell & Kusznir 2008), using BedMap2 data have provided improved estimates of geothermal heat flux (GHF) in Antarctica where it is very poorly known. Continental lithosphere thinning and post-breakup residual thicknesses of continental crust determined from gravity inversion have been used to predict the preservation of continental crustal radiogenic heat productivity and the transient lithosphere heat-flow contribution within thermally equilibrating rifted continental and oceanic lithosphere. The sensitivity of present-day Antarctic top basement heat-flow to initial continental radiogenic heat productivity, continental rift and margin breakup age has been examined. Recognition of the East Antarctic Rift System (EARS), a major Permian to Cretaceous age rift system that appears to extend from the continental margin at the Lambert Rift to the South Pole region, a distance of 2500 km (Ferraccioli et al. 2011) and is comparable in scale to the well-studied East African rift system, highlights that crustal variability in interior Antarctica is much greater than previously assumed. GHF is also important to understand proposed ice accretion at the base of the EAIS in the GSM and its links to sub-ice hydrology (Bell et al. 2011). References Bell, R.E., Ferraccioli, F., Creyts, T.T., Braaten, D., Corr, H., Das, I., Damaske, D., Frearson, N., Jordan, T., Rose, K., Studinger, M. & Wolovick, M. 2011. Widespread persistent thickening of the East Antarctic Ice Sheet by freezing from the base. Science, 331 (6024), 1592-1595. Chappell, A.R. & Kusznir, N.J. 2008. Three-dimensional gravity inversion for Moho depth at rifted continental margins

  4. High geothermal heat flux measured below the West Antarctic Ice Sheet

    PubMed Central

    Fisher, Andrew T.; Mankoff, Kenneth D.; Tulaczyk, Slawek M.; Tyler, Scott W.; Foley, Neil

    2015-01-01

    The geothermal heat flux is a critical thermal boundary condition that influences the melting, flow, and mass balance of ice sheets, but measurements of this parameter are difficult to make in ice-covered regions. We report the first direct measurement of geothermal heat flux into the base of the West Antarctic Ice Sheet (WAIS), below Subglacial Lake Whillans, determined from the thermal gradient and the thermal conductivity of sediment under the lake. The heat flux at this site is 285 ± 80 mW/m2, significantly higher than the continental and regional averages estimated for this site using regional geophysical and glaciological models. Independent temperature measurements in the ice indicate an upward heat flux through the WAIS of 105 ± 13 mW/m2. The difference between these heat flux values could contribute to basal melting and/or be advected from Subglacial Lake Whillans by flowing water. The high geothermal heat flux may help to explain why ice streams and subglacial lakes are so abundant and dynamic in this region. PMID:26601210

  5. High geothermal heat flux measured below the West Antarctic Ice Sheet.

    PubMed

    Fisher, Andrew T; Mankoff, Kenneth D; Tulaczyk, Slawek M; Tyler, Scott W; Foley, Neil

    2015-07-01

    The geothermal heat flux is a critical thermal boundary condition that influences the melting, flow, and mass balance of ice sheets, but measurements of this parameter are difficult to make in ice-covered regions. We report the first direct measurement of geothermal heat flux into the base of the West Antarctic Ice Sheet (WAIS), below Subglacial Lake Whillans, determined from the thermal gradient and the thermal conductivity of sediment under the lake. The heat flux at this site is 285 ± 80 mW/m(2), significantly higher than the continental and regional averages estimated for this site using regional geophysical and glaciological models. Independent temperature measurements in the ice indicate an upward heat flux through the WAIS of 105 ± 13 mW/m(2). The difference between these heat flux values could contribute to basal melting and/or be advected from Subglacial Lake Whillans by flowing water. The high geothermal heat flux may help to explain why ice streams and subglacial lakes are so abundant and dynamic in this region.

  6. A novel heat flux study of a geothermally active lake - Lake Rotomahana, New Zealand

    NASA Astrophysics Data System (ADS)

    Tivey, Maurice A.; de Ronde, Cornel E. J.; Tontini, Fabio Caratori; Walker, Sharon L.; Fornari, Daniel J.

    2016-03-01

    A new technique for measuring conductive heat flux in a lake was adapted from the marine environment to allow for multiple measurements to be made in areas where bottom sediment cover is sparse, or even absent. This thermal blanket technique, pioneered in the deep ocean for use in volcanic mid-ocean rift environments, was recently used in the geothermally active Lake Rotomahana, New Zealand. Heat flow from the lake floor propagates into the 0.5 m diameter blanket and establishes a thermal gradient across the known blanket thickness and thereby provides an estimate of the conductive heat flux of the underlying terrain. This approach allows conductive heat flux to be measured over a spatially dense set of stations in a relatively short period of time. We used 10 blankets and deployed them for 1 day each to complete 110 stations over an 11-day program in the 6 × 3 km lake. Results show that Lake Rotomahana has a total conductive heat flux of about 47 MW averaging 6 W/m2 over the geothermally active lake. The western half of the lake has two main areas of high heat flux; 1) a high heat flux area averaging 21.3 W/m2 along the western shoreline, which is likely the location of the pre-existing geothermal system that fed the famous Pink Terraces, mostly destroyed during the 1886 eruption 2) a region southwest of Patiti Island with a heat flux averaging 13.1 W/m2 that appears to be related to the explosive rift that formed the lake in the 1886 Tarawera eruption. A small rise in bottom water temperature over the survey period of 0.01 °C/day suggests the total thermal output of the lake is ~ 112-132 MW and when compared to the conductive heat output suggests that 18-42% of the total thermal energy is by conductive heat transfer.

  7. Ground heat flux and power sources of low-enthalpy geothermal systems

    NASA Astrophysics Data System (ADS)

    Bayer, Peter; Blum, Philipp; Rivera, Jaime A.

    2015-04-01

    Geothermal heat pumps commonly extract energy from the shallow ground at depths as low as approximately 400 m. Vertical borehole heat exchangers are often applied, which are seasonally operated for decades. During this lifetime, thermal anomalies are induced in the ground and surface-near aquifers, which often grow over the years and which alleviate the overall performance of the geothermal system. As basis for prediction and control of the evolving energy imbalance in the ground, focus is typically set on the ground temperatures. This is reflected in regulative temperature thresholds, and in temperature trends, which serve as indicators for renewability and sustainability. In our work, we examine the fundamental heat flux and power sources, as well as their temporal and spatial variability during geothermal heat pump operation. The underlying rationale is that for control of ground temperature evolution, knowledge of the primary heat sources is fundamental. This insight is also important to judge the validity of simplified modelling frameworks. For instance, we reveal that vertical heat flux from the surface dominates the basal heat flux towards a borehole. Both fluxes need to be accounted for as proper vertical boundary conditions in the model. Additionally, the role of horizontal groundwater advection is inspected. Moreover, by adopting the ground energy deficit and long-term replenishment as criteria for system sustainability, an uncommon perspective is adopted that is based on the primary parameter rather than induced local temperatures. In our synthetic study and dimensionless analysis, we demonstrate that time of ground energy recovery after system shutdown may be longer than what is expected from local temperature trends. In contrast, unrealistically long recovery periods and extreme thermal anomalies are predicted without account for vertical ground heat fluxes and only when the energy content of the geothermal reservoir is considered.

  8. Mapping temperature and radiant geothermal heat flux anomalies in the Yellowstone geothermal system using ASTER thermal infrared data

    USGS Publications Warehouse

    Vaughan, R. Greg; Lowenstern, Jacob B.; Keszthelyi, Laszlo P.; Jaworowski, Cheryl; Heasler, Henry

    2012-01-01

    The purpose of this work was to use satellite-based thermal infrared (TIR) remote sensing data to measure, map, and monitor geothermal activity within the Yellowstone geothermal area to help meet the missions of both the U.S. Geological Survey Yellowstone Volcano Observatory and the Yellowstone National Park Geology Program. Specifically, the goals were to: 1) address the challenges of remotely characterizing the spatially and temporally dynamic thermal features in Yellowstone by using nighttime TIR data from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) and 2) estimate the temperature, geothermal radiant emittance, and radiant geothermal heat flux (GHF) for Yellowstone’s thermal areas (both Park wide and for individual thermal areas). ASTER TIR data (90-m pixels) acquired at night during January and February, 2010, were used to estimate surface temperature, radiant emittance, and radiant GHF from all of Yellowstone’s thermal features, produce thermal anomaly maps, and update field-based maps of thermal areas. A background subtraction technique was used to isolate the geothermal component of TIR radiance from thermal radiance due to insolation. A lower limit for the Yellowstone’s total radiant GHF was established at ~2.0 GW, which is ~30-45% of the heat flux estimated through geochemical (Cl-flux) methods. Additionally, about 5 km2 was added to the geodatabase of mapped thermal areas. This work provides a framework for future satellite-based thermal monitoring at Yellowstone as well as exploration of other volcanic / geothermal systems on a global scale.

  9. High Resolution Geothermal Heat Flux Data--Implications for Ice Sheet Dynamics and Model Uncertainty

    NASA Astrophysics Data System (ADS)

    Johnson, J. V.; Naslund, J. A.; Pattyn, F.; Jansson, P.

    2007-12-01

    Airborne surveys of radiogenic activity in Sweden and Finland have been utilized to create a 5 km resolution map of the geothermal heat flux. Statistical analysis of these data reveal contiguous areas where heat flux is more or less than two standard deviations from the mean. These anomalous areas have a length scale of approximately 22 km. In order to investigate the significance of these findings, thermo-mechanically coupled ice sheet models having both nearly complete and simplified stress treatments are used. Experiments which are formulated for finer scales (~180 km, 10,000 years) utilize the higher order stress treatments, and experiments that treat larger scales (~ 2000 km, 200,000 years) use the reduced stress models. Experiments involve both the measured data, as well as proxies for it, as is appropriate. Experiments also treat a range of sliding relations, and basal water treatments. A novel method of producing synthetic data from the original dataset is formulated, and used to assign confidence intervals to uncertainty estimates. In most all cases, it is found that the ice sheet model is effectively averaging the high resolution geothermal heat flux data, and the results are only marginally different than what would be found using a uniform heat flux boundary condition near the mean of the data set. In cases where it is significantly different, it is the interaction with basal water that provides the mechanism to amplify the impact of a heat flux anomaly.

  10. Method and apparatus for determining vertical heat flux of geothermal field

    DOEpatents

    Poppendiek, Heinz F.

    1982-01-01

    A method and apparatus for determining vertical heat flux of a geothermal field, and mapping the entire field, is based upon an elongated heat-flux transducer (10) comprised of a length of tubing (12) of relatively low thermal conductivity with a thermopile (20) inside for measuring the thermal gradient between the ends of the transducer after it has been positioned in a borehole for a period sufficient for the tube to reach thermal equilibrium. The transducer is thermally coupled to the surrounding earth by a fluid annulus, preferably water or mud. A second transducer comprised of a length of tubing of relatively high thermal conductivity is used for a second thermal gradient measurement. The ratio of the first measurement to the second is then used to determine the earth's thermal conductivity, k.sub..infin., from a precalculated graph, and using the value of thermal conductivity thus determined, then determining the vertical earth temperature gradient, b, from predetermined steady state heat balance equations which relate the undisturbed vertical earth temperature distributions at some distance from the borehole and earth thermal conductivity to the temperature gradients in the transducers and their thermal conductivity. The product of the earth's thermal conductivity, k.sub..infin., and the earth's undisturbed vertical temperature gradient, b, then determines the earth's vertical heat flux. The process can be repeated many times for boreholes of a geothermal field to map vertical heat flux.

  11. Reconstructions of ground surface heat flux variations in the urals from geothermal and meteorological data

    NASA Astrophysics Data System (ADS)

    Demezhko, D. Yu.; Gornostaeva, A. A.

    2015-12-01

    Ground surface heat flux variations over the last 30000, 1000, and 150 years in the Urals were first estimated on the basis of geothermal reconstructions of ground surface temperature histories and meteorological data. The heat flux histories obtained and the factors affecting climate—mean annual insolation, global solar radiation, atmospheric CO2 concentration, and volcanic activity—were simultaneously analyzed. On the scale of glacial-interglacial cycles, variations in the flux of heat almost completely coincided with those in insolation in the Northern Hemisphere, and variations in the content of CO2 occurred 2000-3000 years later synchronously with the response of temperature. In the last 1000 years, heat flux variations have been determined mainly by the parameters of solar radiation; however, the influence of other factors, such as atmospheric CO2 content and volcanic activity, has also been noticeable. In the last 150 years, variations in the flux of heat have occurred in antiphase with those in the flux of solar radiation, and an increase in the atmospheric content of CO2 has mainly contributed to the observed warming.

  12. Ice-Sheet Enhancement of Volcanism and Geothermal Heat Flux: a Stress Modeling Approach

    NASA Astrophysics Data System (ADS)

    Stevens, N. T.; Parizek, B. R.; Alley, R. B.

    2015-12-01

    Bore-hole and geophysically inferred geothermal heat fluxes beneath the Greenland Ice Sheet, particularly at the head of the Northeast Greenland Ice Stream, are in some places higher than suggested by the underlying geology. Geologically rapid changes in lithospheric loading during ice-sheet growth and decay produce large changes in the effective stress state beneath and nearby. Oscillating loads will cause oscillating melt volume in deep rocks, and the nonlinear increase of melt migration velocity with melt fraction means that extended ice-age cycling will enhance upward melt migration. Our numerically efficient simulations of ice-sheet/lithosphere interactions produce crustal stresses similar to values estimated to allow dike emplacement and vug-wave migration. Maximum tensile and shear stresses shift both horizontally and vertically during ice sheet growth and decay, suggesting multi-step transport of melt upwards to or near the base of the ice sheet. We thus suggest that regions of high geothermal heat flux arose from cyclic ice-sheet loading, which enhanced melt extraction from a deep source (possibly linked to passage of the Iceland hot spot). We further suggest that similar processes may have been important elsewhere beneath or near present or former ice sheets, potentially enhancing volcanism as well as geothermal flux.

  13. Geothermal heating

    SciTech Connect

    Aureille, M.

    1982-01-01

    The aim of the study is to demonstrate the viability of geothermal heating projects in energy and economic terms and to provide nomograms from which an initial estimate may be made without having to use data-processing facilities. The effect of flow rate and temperature of the geothermal water on drilling and on the network, and the effect of climate on the type of housing are considered.

  14. Variations in geothermal heat flux at Grímsvötn, Iceland

    NASA Astrophysics Data System (ADS)

    Iona Reynolds, Hannah; Tumi Gudmundsson, Magnús

    2014-05-01

    Thermal signals from sub-surface magmatic sources are difficult to quantify, as the measurement of fluxes from the ground to the atmosphere is subject to large uncertainties. Ice cauldrons are depressions which form on the surface of glaciers due to basal melting as a result of geothermal flux from the bedrock beneath, often generated by volcanic sources. The monitoring of ice cauldrons provides a unique opportunity to quantify heat flux to a much improved accuracy, as the melting ice acts as a calorimeter. Time series data of ice surface elevation at cauldrons above Grímsvötn volcano are presented over a 14 year period, with estimates of the melt volume and surface heat flux required for this melting to have occurred. Three volcanic eruptions took place at Grímsvötn during the study period, the effects of which are visible in ice surface elevation data. However, separate thermal anomalies are observed in areas unaffected by erupted products. A peak in surface heat flux is observed following the 1998 eruption, several kilometres east of the vent, with a maximum rise of ~200 W·m-2. The anomalous signal lasts for approximately three years. Possible explanations include the intrusion of a dyke beneath this area during the eruption, or increased permeability from greater dilatational strain due to regional stress, both of which would significantly increase heat flux. We investigate possible scenarios which could produce such a thermal anomaly, using finite element modelling. The effects of cooling magmatic intrusions and changes to the parameter space for country rock conductivity and permeability are considered, in relation to heat flux and the timescales and spatial extent of associated surface anomalies. Our results advance the understanding and interpretation of thermal signals observed at ice-covered volcanoes.

  15. Inversion of geothermal heat flux in a thermomechanically coupled nonlinear Stokes ice sheet model

    NASA Astrophysics Data System (ADS)

    Zhu, Hongyu; Petra, Noemi; Stadler, Georg; Isaac, Tobin; Hughes, Thomas J. R.; Ghattas, Omar

    2016-07-01

    We address the inverse problem of inferring the basal geothermal heat flux from surface velocity observations using a steady-state thermomechanically coupled nonlinear Stokes ice flow model. This is a challenging inverse problem since the map from basal heat flux to surface velocity observables is indirect: the heat flux is a boundary condition for the thermal advection-diffusion equation, which couples to the nonlinear Stokes ice flow equations; together they determine the surface ice flow velocity. This multiphysics inverse problem is formulated as a nonlinear least-squares optimization problem with a cost functional that includes the data misfit between surface velocity observations and model predictions. A Tikhonov regularization term is added to render the problem well posed. We derive adjoint-based gradient and Hessian expressions for the resulting partial differential equation (PDE)-constrained optimization problem and propose an inexact Newton method for its solution. As a consequence of the Petrov-Galerkin discretization of the energy equation, we show that discretization and differentiation do not commute; that is, the order in which we discretize the cost functional and differentiate it affects the correctness of the gradient. Using two- and three-dimensional model problems, we study the prospects for and limitations of the inference of the geothermal heat flux field from surface velocity observations. The results show that the reconstruction improves as the noise level in the observations decreases and that short-wavelength variations in the geothermal heat flux are difficult to recover. We analyze the ill-posedness of the inverse problem as a function of the number of observations by examining the spectrum of the Hessian of the cost functional. Motivated by the popularity of operator-split or staggered solvers for forward multiphysics problems - i.e., those that drop two-way coupling terms to yield a one-way coupled forward Jacobian - we study the

  16. Geothermal Heat Flux: Linking Deep Earth's Interior and the Dynamics of Large-Scale Ice Sheets

    NASA Astrophysics Data System (ADS)

    Rogozhina, Irina; Vaughan, Alan

    2014-05-01

    Greenland results from the remanent effects of an Early Cenozoic passage of the lithosphere above the Iceland mantle plume that is implicated in strong thermochemical erosion of the lithosphere and significant long-term effects on the present-day subglacial heat flow pattern and thermodynamic state of the Greenland ice sheet. These observations and our modeling results (Petrunin et al., 2013) show that the present-day thermal state of Greenland and Antarctic lithosphere cannot be well understood without taking into account a long-term tectonic history of these regions. The goal of the IceGeoHeat project is to combine existing independent geophysical data and innovative modeling approaches to comprehensively study the evolution and present state of the lithosphere in Greenland and Antarctica, and assess the role of geothermal heat flux in shaping the present-day ice sheet dynamics. This requires multiple collaborations involving experts across a range of disciplines. The project builds on the IceGeoHeat initiative formed in April 2012 and now including researchers from ten countries in the main core (MC) with expertise in numerical modeling and data assessment in geodynamics, geology, geothermics, cryosphere and (paleo-)climate. Petrunin, A., Rogozhina, I., Vaughan, A. P. M., Kukkonen, I. T., Kaban, M., Koulakov, I., Thomas, M. (2013): Heat flux variations beneath central Greenland's ice due to anomalously thin lithosphere. - Nature Geoscience, 6, 746-750.

  17. Geothermal Heat Flux Assessment Using Remote Sensing Land Surface Temperature and Simulated Data. Case Studies at the Kenyan Rift and Yellowstone Geothermal Areas

    NASA Astrophysics Data System (ADS)

    Romaguera, M.; Vaughan, R. G.; Ettema, J.; Izquierdo-Verdiguier, E.; Hecker, C.; van der Meer, F. D.

    2015-12-01

    In this work we propose an innovative approach to assess the geothermal heat flux anomalies in the regions of the Kenyan Rift and the Yellowstone geothermal areas. The method is based on the land surface temperature (LST) differences obtained between remote sensing data and land surface model simulations. The hypothesis is that the model simulations do not account for the subsurface geothermal heat source in the formulation. Remote sensing of surface emitted radiances is able to detect at least the radiative portion of the geothermal signal that is not in the models. Two methods were proposed to assess the geothermal component of LST (LSTgt) based on the aforementioned hypothesis: a physical model and a data mining approach. The LST datasets were taken from the Land Surface Analysis Satellite Application Facilities products over Africa and the Copernicus Programme for North America, at a spatial resolution of 3-5 km. These correspond to Meteosat Second Generation and Geostationary Operational Environmental Satellite system satellites data respectively. The Weather Research and Forecasting model was used to simulate LST based on atmospheric and surface characteristics using the Noah land surface model. The analysis was carried out for a period of two months by using nighttime acquisitions. Higher spatial resolution images from the Advanced Spaceborne Thermal Emission and Reflection Radiometer data were also used on the Kenyan area to produce similar outputs employing existing methods. The comparison of the results from both methods and areas illustrated the potential of the data and methodologies for geothermal applications.

  18. Optimizing Sustainable Geothermal Heat Extraction

    NASA Astrophysics Data System (ADS)

    Patel, Iti; Bielicki, Jeffrey; Buscheck, Thomas

    2016-04-01

    Geothermal heat, though renewable, can be depleted over time if the rate of heat extraction exceeds the natural rate of renewal. As such, the sustainability of a geothermal resource is typically viewed as preserving the energy of the reservoir by weighing heat extraction against renewability. But heat that is extracted from a geothermal reservoir is used to provide a service to society and an economic gain to the provider of that service. For heat extraction used for market commodities, sustainability entails balancing the rate at which the reservoir temperature renews with the rate at which heat is extracted and converted into economic profit. We present a model for managing geothermal resources that combines simulations of geothermal reservoir performance with natural resource economics in order to develop optimal heat mining strategies. Similar optimal control approaches have been developed for managing other renewable resources, like fisheries and forests. We used the Non-isothermal Unsaturated-saturated Flow and Transport (NUFT) model to simulate the performance of a sedimentary geothermal reservoir under a variety of geologic and operational situations. The results of NUFT are integrated into the optimization model to determine the extraction path over time that maximizes the net present profit given the performance of the geothermal resource. Results suggest that the discount rate that is used to calculate the net present value of economic gain is a major determinant of the optimal extraction path, particularly for shallower and cooler reservoirs, where the regeneration of energy due to the natural geothermal heat flux is a smaller percentage of the amount of energy that is extracted from the reservoir.

  19. Geothermal District Heating Economics

    1995-07-12

    GEOCITY is a large-scale simulation model which combines both engineering and economic submodels to systematically calculate the cost of geothermal district heating systems for space heating, hot-water heating, and process heating based upon hydrothermal geothermal resources. The GEOCITY program simulates the entire production, distribution, and waste disposal process for geothermal district heating systems, but does not include the cost of radiators, convectors, or other in-house heating systems. GEOCITY calculates the cost of district heating basedmore » on the climate, population, and heat demand of the district; characteristics of the geothermal resource and distance from the distribution center; well-drilling costs; design of the distribution system; tax rates; and financial conditions.« less

  20. Variable crustal thickness beneath Thwaites Glacier revealed from airborne gravimetry, possible implications for geothermal heat flux in West Antarctica

    NASA Astrophysics Data System (ADS)

    Damiani, Theresa M.; Jordan, Tom A.; Ferraccioli, Fausto; Young, Duncan A.; Blankenship, Donald D.

    2014-12-01

    Thwaites Glacier has one of the largest glacial catchments in West Antarctica. The future stability of Thwaites Glacier's catchment is of great concern, as this part of the West Antarctic Ice Sheet has recently been hypothesized to already be en route towards collapse. Although an oceanic trigger is thought to be responsible for current change at the grounding line of Thwaites Glacier, in order to determine the effects of this coastal change further in the interior of the West Antarctic Ice Sheet it is essential to also better constrain basal conditions that control the dynamics of fast glacial flow within the catchment itself. One major contributor to fast glacial flow is the presence of subglacial water, the production of which is a result of both glaciological shear heating and geothermal heat flux. The primary goal of our study is to investigate the crustal thickness beneath Thwaites Glacier, which is an important contributor to regional-scale geothermal heat flux patterns. Crustal structure is an indicator of past tectonic events and hence provides a geophysical proxy for the thermal status of the crust and mantle. Terrain-corrected Bouguer gravity disturbances are used here to estimate depths to the Moho and mid-crustal boundary. The thin continental crust we reveal beneath Thwaites Glacier supports the hypothesis that the West Antarctic Rift System underlies the region and is expressed topographically as the Byrd Subglacial Basin. This rifted crust is of similar thickness to that calculated from airborne gravity data beneath neighboring Pine Island Glacier, and is more extended than crust in the adjacent Siple Coast sector of the Ross Sea Embayment. A zone of thinner crust is also identified near the area's subaerial volcanoes lending support to a recent interpretation predicting that this part of Marie Byrd Land is a major volcanic dome, likely within the West Antarctic Rift System itself. Near-zero Bouguer gravity disturbances for the subglacial highlands

  1. The Heat Output of the Waimangu, Waiotapu-Waikite and Reporoa Geothermal Systems (NZ): Do Chloride Fluxes Provide an Accurate Measure?

    SciTech Connect

    Bibby, H.M.; Glover, R.B.; Whiteford, P.C.

    1995-01-01

    Geothermal waters from the Waimangu, Waiotapu-Waikite and Reporoa geothermal systems find their way into three separate watersheds. The heat flow data from each of these drainage areas have been assessed making it possible to compare the heat outputs from two independent methods: direct heat measurements and the chloride flux method. For both the Waiotapu/Reporoa Valley drainage and the Waikite drainage a discrepancy exists between the two assessments, with the heat output observed at the surface (Waiotapu-540 {+-} 110 MW; Waikite-80 MW) nearly double of that calculated from the chloride flux (300 MW; 36 MW respectively). It appears that much of the throughput of chloride does not reach the surface within the area which was monitored and the basic assumption on which the method is based has been violated. For Waimangu the direct heat output is assessed as 510 {+-} 60 MW. However the ratio of enthalpy to chloride concentration of the source fluid is not well determined. Depending on the ratio chosen the heat output could lie between 360 and 800 MW. Although the chloride flux is accurately known, the heat output cannot be measured accurately without well determined data on the source fluid at depth.

  2. Enhancement of volcanism and geothermal heat flux by ice-age cycling: A stress modeling study of Greenland

    NASA Astrophysics Data System (ADS)

    Stevens, Nathan T.; Parizek, Byron R.; Alley, Richard B.

    2016-08-01

    Ice-age cycling of the Greenland ice sheet likely contributed to locally elevated subglacial geothermal heat fluxes (GHFs), based on recent thermal modeling. Borehole and geophysical data indicate higher GHF in some areas than suggested by current knowledge of underlying geology, particularly at the head of the Northeast Greenland Ice Stream. Changes in lithospheric loading during ice-sheet growth and decay cycles produce large and geologically rapid changes in the effective stress state beneath and near the ice sheet. Oscillations in melt fraction from cyclic loading through multiple ice-age cycles will enhance upward magma migration through the nonlinear increase of melt migration velocity with melt fraction. We simulate periodic ice-sheet loading scenarios along an east-west transect across central Greenland on an Elastic Lithosphere, Relaxed Asthenosphere Earth model. Under likely parameter ranges, deviatoric stresses in the elastic lithosphere across widespread regions are sufficiently high to meaningfully enhance dike emplacement and also allow vug-wave propagation in some scenarios. Stress patterns migrate laterally in response to ice-sheet dynamics, favoring multistage magma ascent. If melt occurs at depth, our modeling suggests that ice-age cycling could help it migrate upward to shallow depth or erupt, contributing to the high observed GHF. Furthermore, shallow magma emplacement might feed hydrothermal systems exploiting enhanced faulting or fracturing from ice-age cycling, adding to elevated GHF. The preglacial passage of the Iceland-Jan Mayen hot spot could have sourced such magmas. Direct observations of these lithospheric processes needed to further constrain our models are limited, highlighting the value of more targeted geophysical studies informing future modeling.

  3. Energy 101: Geothermal Heat Pumps

    ScienceCinema

    None

    2016-07-12

    An energy-efficient heating and cooling alternative, the geothermal heat pump system moves heat from the ground to a building (or from a building to the ground) through a series of flexible pipe "loops" containing water. This edition of Energy 101 explores the benefits Geothermal and the science behind how it all comes together.

  4. Energy 101: Geothermal Heat Pumps

    SciTech Connect

    2011-01-01

    An energy-efficient heating and cooling alternative, the geothermal heat pump system moves heat from the ground to a building (or from a building to the ground) through a series of flexible pipe "loops" containing water. This edition of Energy 101 explores the benefits Geothermal and the science behind how it all comes together.

  5. Heat flux measurements

    NASA Technical Reports Server (NTRS)

    Liebert, Curt H.; Weikle, Donald H.

    1989-01-01

    A new automated, computer controlled heat flux measurement facility is described. Continuous transient and steady-state surface heat flux values varying from about 0.3 to 6 MW/sq m over a temperature range of 100 to 1200 K can be obtained in the facility. An application of this facility is the development of heat flux gauges for continuous fast transient surface heat flux measurement on turbine blades operating in space shuttle main engine turbopumps. The facility is useful for durability testing at fast temperature transients.

  6. Optimal Management of Geothermal Heat Extraction

    NASA Astrophysics Data System (ADS)

    Patel, I. H.; Bielicki, J. M.; Buscheck, T. A.

    2015-12-01

    Geothermal energy technologies use the constant heat flux from the subsurface in order to produce heat or electricity for societal use. As such, a geothermal energy system is not inherently variable, like systems based on wind and solar resources, and an operator can conceivably control the rate at which heat is extracted and used directly, or converted into a commodity that is used. Although geothermal heat is a renewable resource, this heat can be depleted over time if the rate of heat extraction exceeds the natural rate of renewal (Rybach, 2003). For heat extraction used for commodities that are sold on the market, sustainability entails balancing the rate at which the reservoir renews with the rate at which heat is extracted and converted into profit, on a net present value basis. We present a model that couples natural resource economic approaches for managing renewable resources with simulations of geothermal reservoir performance in order to develop an optimal heat mining strategy that balances economic gain with the performance and renewability of the reservoir. Similar optimal control approaches have been extensively studied for renewable natural resource management of fisheries and forests (Bonfil, 2005; Gordon, 1954; Weitzman, 2003). Those models determine an optimal path of extraction of fish or timber, by balancing the regeneration of stocks of fish or timber that are not harvested with the profit from the sale of the fish or timber that is harvested. Our model balances the regeneration of reservoir temperature with the net proceeds from extracting heat and converting it to electricity that is sold to consumers. We used the Non-isothermal Unconfined-confined Flow and Transport (NUFT) model (Hao, Sun, & Nitao, 2011) to simulate the performance of a sedimentary geothermal reservoir under a variety of geologic and operational situations. The results of NUFT are incorporated into the natural resource economics model to determine production strategies that

  7. Experiments Demonstrate Geothermal Heating Process

    ERIC Educational Resources Information Center

    Roman, Harry T.

    2012-01-01

    When engineers design heat-pump-based geothermal heating systems for homes and other buildings, they can use coil loops buried around the perimeter of the structure to gather low-grade heat from the earth. As an alternative approach, they can drill well casings and store the summer's heat deep in the earth, then bring it back in the winter to warm…

  8. Guide to Geothermal Heat Pumps

    SciTech Connect

    2011-02-01

    Geothermal heat pumps, also known as ground source heat pumps, geoexchange, water-source, earth-coupled, and earth energy heat pumps, take advantage of this resource and represent one of the most efficient and durable options on the market to heat and cool your home.

  9. Geothermal heating for Caliente, Nevada

    SciTech Connect

    Wallis, F.; Schaper, J.

    1981-02-01

    Utilization of geothermal resources in the town of Caliente, Nevada (population 600) has been the objective of two grants. The first grant was awarded to Ferg Wallis, part-owner and operator of the Agua Caliente Trailer Park, to assess the potential of hot geothermal water for heating the 53 trailers in his park. The results from test wells indicate sustainable temperatures of 140/sup 0/ to 160/sup 0/F. Three wells were drilled to supply all 53 trailers with domestic hot water heating, 11 trailers with space heating and hot water for the laundry from the geothermal resource. System payback in terms of energy cost-savings is estimated at less than two years. The second grant was awarded to Grover C. Dils Medical Center in Caliente to drill a geothermal well and pipe the hot water through a heat exchanger to preheat air for space heating. This geothermal preheater served to convert the existing forced air electric furnace to a booster system. It is estimated that the hospital will save an average of $5300 in electric bills per year, at the current rate of $.0275/KWH. This represents a payback of approximately two years. Subsequent studies on the geothermal resource base in Caliente and on the economics of district heating indicate that geothermal may represent the most effective supply of energy for Caliente. Two of these studies are included as appendices.

  10. Geothermal direct-heat utilization assistance

    NASA Astrophysics Data System (ADS)

    The report summarizes activities of the Geo-Heat Center (GHC) at Oregon Institute of Technology for the first quarter of Fiscal Year 1995. It describes contacts with parties during this period related to assistance with geothermal direct heat projects. Areas dealt with include geothermal heat pumps, space heating, greenhouses, aquaculture, resources and equipment. Research is also being conducted on geothermal energy cost evaluation, low-temperature geothermal resource assessment, use of silica waste from the Cerro Prieto geothermal field as construction materials and geothermal heat pumps. Outreach activities include the publication of a quarterly bulletin on direct heat applications and dissemination of information on low-temperature geothermal resources and utilization.

  11. Heat Flux Sensor

    NASA Technical Reports Server (NTRS)

    1994-01-01

    A heat flux microsensor developed under a NASP Small Business Innovation Research (SBIR) has a wide range of potential commercial applications. Vatell Corporation originally designed microsensors for use in very high temperatures. The company then used the technology to develop heat flux sensors to measure the rate of heat energy flowing in and out of a surface as well as readings on the surface temperature. Additional major advantages include response to heat flux in less than 10 microseconds and the ability to withstand temperatures up to 1,200 degrees centigrade. Commercial applications are used in high speed aerodynamics, supersonic combustion, blade cooling, and mass flow measurements, etc.

  12. Combined Geothermal Potential of Subsurface Urban Heat Islands

    NASA Astrophysics Data System (ADS)

    Benz, Susanne; Bayer, Peter; Menberg, Kathrin; Blum, Philipp

    2016-04-01

    The subsurface urban heat island (SUHI) can be seen as a geothermal potential in form of elevated groundwater temperatures caused by anthropogenic heat fluxes into the subsurface. In this study, these fluxes are quantified for an annual timeframe in two German cities, Karlsruhe and Cologne. Our two-dimensional (2D) statistical analytical model determines the renewable and sustainable geothermal potential caused by six vertical anthropogenic heat fluxes into the subsurface: from (1) elevated ground surface temperatures, (2) basements, (3) sewage systems, (4) sewage leakage, (5) subway tunnels, and (6) district heating networks. The results show that at present 2.15 ± 1.42 PJ and 0.99 ± 0.32 PJ of heat are annually transported into the shallow groundwater of Karlsruhe and Cologne, respectively, due to anthropogenic heat fluxes into the subsurface. This is sufficient to sustainably cover 32% and 9% of the annual residential space heating demand of Karlsruhe and Cologne, respectively. However, most of the discussed anthropogenic fluxes into the subsurface are conductive heat fluxes and therefore dependent on the groundwater temperature itself. Accordingly, a decrease in groundwater temperature back to its natural (rural) state, achieved through the use of geothermal heat pumps, will increase these fluxes and with them the sustainable potential. Hence, we propose the introduction of a combined geothermal potential that maximizes the sustainability of urban shallow geothermal energy use and the efficiency of shallow geothermal systems by balancing groundwater temperature with anthropogenic heat fluxes into the subsurface. This will be a key element in the development of a demand-oriented, cost-efficient geothermal management tool with an additional focus on the sustainability of the urban heat sources.

  13. Geothermal heat pumps in Pierre

    SciTech Connect

    Wegman, S.

    1997-12-01

    There are two municipal connected heat pumps in Pierre, South Dakota: the South Dakota Discovery Center and Pierre City Hall.Both systems now utilize plate heat exchanger between the city water loop and the building loop. This article describes the geothermal system used in Pierre for both space heating and cooling of municipal buildings.

  14. Geothermal heat in a heat pump use

    NASA Astrophysics Data System (ADS)

    Pavlova, A.; Hansen, J.; Obermeyer, H.; Pavlova, I.

    2016-09-01

    The considered innovative technology proposes to use alternative energy sources for the process efficiency in low-height construction. The world economy depends on price rises for energy sources and the danger of environmental pollution increases. Geothermal energy is the basic resource saving and environmentally safe renewable heat source that is characterized by inexhaustibility, permanent all the-year-round use, universal prevalence of resources and the ability to replace considerable volumes of traditional energy carriers. The expediency and power efficiency to apply a heat pump with the use of geothermal heat is proved for low-height construction.

  15. Geothermal district heating systems

    SciTech Connect

    Budney, G.S.; Childs, F.

    1982-01-01

    Ten district heating demonstration projects and their present status are described. The projects are Klamath County YMCA, Susanville District Heating, Klamath Falls District Heating, Reno Salem Plaza Condominium, El Centro Community Center Heating/Cooling, Haakon School and Business District Heating, St. Mary's Hospital, Diamond Ring Ranch, Pagosa Springs District Heating, and Boise District Heating.

  16. Optical heat flux gauge

    DOEpatents

    Noel, Bruce W.; Borella, Henry M.; Cates, Michael R.; Turley, W. Dale; MaCarthur, Charles D.; Cala, Gregory C.

    1991-01-01

    A heat flux gauge comprising first and second thermographic phosphor layers separated by a layer of a thermal insulator. The gauge may be mounted on a surface with the first thermographic phosphor in contact with the surface. A light source is directed at the gauge, causing the phosphors to luminesce. The luminescence produced by the phosphors is collected and its spectra analyzed in order to determine the heat flux on the surface. First and second phosphor layers must be different materials to assure that the spectral lines collected will be distinguishable.

  17. Optical heat flux gauge

    DOEpatents

    Noel, Bruce W.; Borella, Henry M.; Cates, Michael R.; Turley, W. Dale; MacArthur, Charles D.; Cala, Gregory C.

    1991-01-01

    A heat flux gauge comprising first and second thermographic phosphor layers separated by a layer of a thermal insulator wherein each thermographic layer comprises a plurality of respective thermographic phosphors. The gauge may be mounted on a surface with the first thermographic phosphor in contact with the surface. A light source is directed at the gauge, causing the phosphors to luminesce. The luminescence produced by the phosphors is collected and its spectra analyzed in order to determine the heat flux on the surface. First and second phosphor layers must be different materials to assure that the spectral lines collected will be distinguishable.

  18. Optical heat flux gauge

    DOEpatents

    Noel, Bruce W.; Borella, Henry M.; Cates, Michael R.; Turley, W. Dale; MacArthur, Charles D.; Cala, Gregory C.

    1991-01-01

    A heat flux gauge comprising first and second thermographic phosphor layers separated by a layer of a thermal insulator, wherein each thermographic layer comprises a plurality of respective thermographic sensors in a juxtaposed relationship with respect to each other. The gauge may be mounted on a surface with the first thermographic phosphor in contact with the surface. A light source is directed at the gauge, causing the phosphors to luminesce. The luminescence produced by the phosphors is collected and its spectra analyzed in order to determine the heat flux on the surface. First and second phosphor layers must be different materials to assure that the spectral lines collected will be distinguishable.

  19. High flux heat exchanger

    NASA Astrophysics Data System (ADS)

    Flynn, Edward M.; Mackowski, Michael J.

    1993-01-01

    This interim report documents the results of the first two phases of a four-phase program to develop a high flux heat exchanger for cooling future high performance aircraft electronics. Phase 1 defines future needs for high flux heat removal in advanced military electronics systems. The results are sorted by broad application categories: (1) commercial digital systems, (2) military data processors, (3) power processors, and (4) radar and optical systems. For applications expected to be fielded in five to ten years, the outlook is for steady state flux levels of 30-50 W/sq cm for digital processors and several hundred W/sq cm for power control applications. In Phase 1, a trade study was conducted on emerging cooling technologies which could remove a steady state chip heat flux of 100 W/sq cm while holding chip junction temperature to 90 C. Constraints imposed on heat exchanger design, in order to reflect operation in a fighter aircraft environment, included a practical lower limit on coolant supply temperature, the preference for a nontoxic, nonflammable, and nonfreezing coolant, the need to minimize weight and volume, and operation in an accelerating environment. The trade study recommended the Compact High Intensity Cooler (CHIC) for design, fabrication, and test in the final two phases of this program.

  20. Latent Heat in Soil Heat Flux Measurements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The surface energy balance includes a term for soil heat flux. Soil heat flux is difficult to measure because it includes conduction and convection heat transfer processes. Accurate representation of soil heat flux is an important consideration in many modeling and measurement applications. Yet, the...

  1. Idealised modelling of ocean circulation driven by geothermal and hydrothermal fluxes at the seabed

    NASA Astrophysics Data System (ADS)

    Barnes, Jowan; Morales Maqueda, Miguel; Polton, Jeff

    2016-04-01

    There are two distinct processes by which heat is transferred from the solid Earth into the abyssal ocean. The first is conductive geothermal heating and the second is hydrothermal heating, involving advection of heated water from within the Earth's crust. Here, the noticeably different impacts of these two physical systems on ocean circulation are investigated. Previous modelling studies have applied geothermal heat fluxes at the seabed and shown discrepancies in circulation compared to cases which neglected heat from the Earth in their boundary conditions. The true heat flux in the ocean, however, is not entirely geothermal. From areas where the crust is younger a significant proportion of the heat input from the Earth could be in the form of fluid flow from hydrothermal vents, introducing forcing to the circulation which has previously been unaccounted for. In this study a set of idealised modelling experiments are run in order to investigate the effects of changing the balance of the total heat flux from purely geothermal to purely hydrothermal, via intermediate states in which the two boundary conditions are combined in different ratios. By performing such experiments it will be shown which of the two processes is dominant in its effects on circulation driven by heating at the seabed, and whether neglecting the hydrothermal advection in favour of a fully conductive geothermal boundary condition is justifiable. The results will inform the construction of boundary conditions for future circulation models involving ocean floor heat fluxes, specifically a regional study of geothermal and hydrothermal contributions within the Panama Basin.

  2. Boise geothermal district heating system

    SciTech Connect

    Hanson, P.J.

    1985-10-01

    This document describes the Boise geothermal district heating project from preliminary feasibility studies completed in 1979 to a fully operational system by 1983. The report includes information about the two local governments that participated in the project - the City of Boise, Idaho and the Boise Warm Springs Water District. It also discusses the federal funding sources; the financial studies; the feasibility studies conducted; the general system planning and design; design of detailed system components; the legal issues involved in production; geological analysis of the resource area; distribution and disposal; the program to market system services; and the methods of retrofitting buildings to use geothermal hot water for space heating. Technically this report describes the Boise City district heating system based on 170/sup 0/F water, a 4000 gpm production system, a 41,000 foot pipeline system, and system economies. Comparable data are also provided for the Boise Warm Springs Water District. 62 figs., 31 tabs.

  3. Geothermal Heat Pumps for Federal Buildings

    SciTech Connect

    1999-08-01

    OFFICE OF GEOTHERMAL TECHNOLOGIES Geothermal Heat Pumps for Federal Buildings The U.S. Government spends approximately $8 billion annually on its energy needs. To reduce energy use in Federal buildings, President Bill Clinton issued Executive Order 13123 in June 1999, which calls for a 35% reduction in Federal energy use from 1985 levels by 2010. Geothermal heat pumps--when installed in virtually any type of building--can help accomplish this goal with energy savings of up to 40%. Geothermal he.

  4. Optical heat flux gauge

    DOEpatents

    Noel, B.W.; Borella, H.M.; Cates, M.R.; Turley, W.D.; MacArthur, C.D.; Cala, G.C.

    1991-04-09

    A heat flux gauge is disclosed comprising first and second thermographic phosphor layers separated by a layer of a thermal insulator, wherein each thermographic layer comprises a plurality of respective thermographic sensors in a juxtaposed relationship with respect to each other. The gauge may be mounted on a surface with the first thermographic phosphor in contact with the surface. A light source is directed at the gauge, causing the phosphors to luminesce. The luminescence produced by the phosphors is collected and its spectra analyzed in order to determine the heat flux on the surface. First and second phosphor layers must be different materials to assure that the spectral lines collected will be distinguishable. 9 figures.

  5. Geothermal Heat Transfer

    SciTech Connect

    Basmajian, V.V.

    1986-01-28

    This patent describes a heat transfer apparatus which consists of: heat exchanging means for orientation in the earth below ground substantially vertically, having a hollow conduit of length from top to bottom much greater than the span across the hollow conduit orthogonal to its length with a top, bottom and an intermediate portion contiguous and communicating with the top and bottom portions for allowing thermally conductive fluid to flow freely between the top, intermediate and bottom portions for immersion in thermally conductive fluid in the region around the heat exchanging means for increasing the heat flow between the latter and earth when inserted into a substantially vertical borehole in the earth with the top portion above the bottom portion. The heat exchanger consists of heat exchanging conduit means in the intermediate portion for carrying refrigerant. The heat exchanging conduit consisting of tubes of thermally conductive material for carrying the refrigerant and extending along the length of the hollow conduit for a tube length that is less than the length of the hollow conduit. The hollow conduit is formed with port means between the top and the plurality of tubes for allowing the thermally conductive fluid to pass in a flow path embracing the tubes, the bottom portion, an outer channel around the hollow conduit and the port means.

  6. Heat Flux Sensor Testing

    NASA Technical Reports Server (NTRS)

    Clark, D. W.

    2002-01-01

    This viewgraph presentation provides information on the following objectives: Developing secondary calibration capabilities for MSFC's (Marshall Space Flight Center) Hot Gas Facility (HGF), a Mach 4 Aerothermal Wind Tunnel; Evaluating ASTM (American Society for Testing and Materials) slug/ thinskin calorimeters against current HGF heat flux sensors; Providing verification of baselined AEDC (Arnold Engineering Development Center) / Medtherm gage calibrations; Addressing future calibration issues involving NIST (National Institute of Standards and Technology) certified radiant gages.

  7. Geothermal Heat Pump Benchmarking Report

    SciTech Connect

    1997-01-17

    A benchmarking study was conducted on behalf of the Department of Energy to determine the critical factors in successful utility geothermal heat pump programs. A Successful program is one that has achieved significant market penetration. Successfully marketing geothermal heat pumps has presented some major challenges to the utility industry. However, select utilities have developed programs that generate significant GHP sales. This benchmarking study concludes that there are three factors critical to the success of utility GHP marking programs: (1) Top management marketing commitment; (2) An understanding of the fundamentals of marketing and business development; and (3) An aggressive competitive posture. To generate significant GHP sales, competitive market forces must by used. However, because utilities have functioned only in a regulated arena, these companies and their leaders are unschooled in competitive business practices. Therefore, a lack of experience coupled with an intrinsically non-competitive culture yields an industry environment that impedes the generation of significant GHP sales in many, but not all, utilities.

  8. Groundwater and geothermal: urban district heating applications

    SciTech Connect

    Mounts, R.; Frazier, A.; Wood, E.; Pyles, O.

    1982-01-01

    This report describes how several cities use groundwater and geothermal energy in district heating systems. It begins with groundwater, introducing the basic technology and techniques of development, and describing two case studies of cities with groundwater-based district heating systems. The second half of the report consists of three case studies of cities with district heating systems using higher temperature geothermal resources.

  9. Geothermal community heating for Cape Charles, Virginia

    NASA Astrophysics Data System (ADS)

    Leffel, C. S., Jr.

    1981-10-01

    An economic feasibility study for a geothermal community heating system was made for the residential heat load of Cape Charles, Virginia using a computer program. The effects of inflation, interest rates, wellhead temperatures, and the addition of reinjection wells are investigated. It is concluded that the utilization of geothermal energy would be feasible if well flows of 500 gal/minute could be obtained and if reinjection of the geothermal fluids were not required. A comparison of the geothermal assisted community system with a coal fired system shows that the coal fired system may be the most attractive alternative to the heating of homes with individual oil fired furnaces.

  10. Midland, South Dakota geothermal district heating

    SciTech Connect

    Lund, J.W.

    1997-12-01

    This article describes historical aspects and present usage of geothermal district heating systems in the town of Midland, South Dakota. The use of geothermal resources exists due to a joint venture between the school district and the city back in the early 1960`s. A total of approximately 30,000 square feet (2800 square meters) of floor space is heated using geothermal energy in Midland. This provides an estimated annual saving in propane cost of $15,000 to the community.

  11. Modelled and observed continental surface heat fluxes

    NASA Astrophysics Data System (ADS)

    Beltrami, H.; MacDougall, A. H.; Gonzalez-Rouco, F. J.; Stevens, M. B.; Bourlon, E.

    2009-12-01

    Heat fluxes in the continental subsurface were estimated from general circulation model (GCM) simulations of the climate of the last millennium and compared to those obtained from subsurface geothermal data. Since GCMs have bottom boundary conditions (BBCs) that are less than 10 m deep and thus may be thermodynamically restricted in the continental subsurface, we used an idealized land surface model (LSM) with a very deep BBC to estimate the potential for realistic subsurface heat storage in the absence of bottom boundary constraints. Results indicate that there is good agreement between observed fluxes and GCM simulated fluxes for the 1780-1980 period when the GCM simulated temperatures are coupled to the LMS with deep BBC. These results emphasize the importance of placing a deep BBC in GCM soil components for the proper simulation of the overall continental heat budget. In addition, the agreement between the LSM surface fluxes and the borehole temperature reconstructed fluxes lends additional support to the overall quality of the GCM (ECHO-G) paleoclimatic simulations. Simulations to 2100 show a divergence between the LSM simulated subsurface heat content and the heat gain in the ECHO-G soil model, with the placement of the BBCs surpassing the thermodynamical effect of the choice of emission scenario as the most important factor determining heat absorption in the simulated subsurface.

  12. Philip, South Dakota geothermal district heating systems

    SciTech Connect

    Lund, J.W.

    1997-12-01

    The geothermal heating project in Philip, South Dakota which uses the waste water from the Haakon School has now been in operation for 15 years. This project was one of the 23 cost shared by the U.S. DOE starting in 1978, of which 15 became operational. This article describes the geothermal heating system for eight buildings in downtown Philip.

  13. Heat-Flux-Measuring Facility

    NASA Technical Reports Server (NTRS)

    Liebert, Curt H.; Weikle, Donald H.

    1990-01-01

    Apparatus simulates conditions in turbine engines. Automated facility generates and measures transient and steady-state heat fluxes at flux densities from 0.3 to 6 MW/m(Sup2) and temperatures from 100 to 1,200 K. Positioning arm holds heat-flux gauge at focal point of arc lamp. Arm previously chilled gauge in liquid nitrogen in Dewar flask. Cooling water flows through lamp to heat exchanger. Used to develop heat-flux gauges for turbine blades and to test materials for durability under rapidly changing temperatures.

  14. DOE Webinar - Residential Geothermal Heat Pump Retrofits (Presentation)

    SciTech Connect

    Anderson, E. R.

    2010-12-14

    This presentation was given December 14, 2010, as part of DOE's Webinar series. The presentation discusses geothermal heat pump retrofits, technology options, and an overview of geothermal energy and geothermal heat pumps.

  15. Geothermal heat pump grouting materials

    SciTech Connect

    Allan, M.

    1998-08-01

    The thermal conductivity of cementitious grouts has been investigated in order to determine suitability of these materials for grouting vertical boreholes used with geothermal heat pumps. The roles of mix variables such as water/cement ratio, sand/cement ratio and superplasticizer dosage were measured. The cement-sand grouts were also tested for rheological characteristics, bleeding, permeability, bond to HDPE pipe, shrinkage, coefficient of thermal expansion, exotherm, durability and environmental impact. This paper summarizes the thermal conductivity, permeability, bonding and exotherm data for selected cementitious grouts. The theoretical reduction in bore length that could be achieved with the BNL-developed cement-sand grouts is examined. Finally, the FY 98 research and field trials are discussed.

  16. GEOTHERMAL HEAT PUMP GROUTING MATERIALS

    SciTech Connect

    ALLAN,M.

    1998-04-01

    The thermal conductivity of cementitious grouts has been investigated in order to determine suitability of these materials for grouting vertical boreholes used with geothermal heat pumps. The roles of mix variables such as water/cement ratio, sand/cement ratio and superplasticizer dosage were measured. The cement-sand grouts were also tested for rheological characteristics, bleeding, permeability, bond to HDPE pipe, shrinkage, coefficient of thermal expansion, exotherm, durability and environmental impact. This paper summarizes the thermal conductivity, permeability, bonding and exotherm data for selected cementitious grouts. The theoretical reduction in bore length that could be achieved with the BNL-developed cement-sand grouts is examined. Finally, the FY 98 research and field trials are discussed.

  17. Geothermal Energy Production With Innovative Methods Of Geothermal Heat Recovery

    SciTech Connect

    Swenson, Allen; Darlow, Rick; Sanchez, Angel; Pierce, Michael; Sellers, Blake

    2014-12-19

    The ThermalDrive™ Power System (“TDPS”) offers one of the most exciting technological advances in the geothermal power generation industry in the last 30 years. Using innovations in subsurface heat recovery methods, revolutionary advances in downhole pumping technology and a distributed approach to surface power production, GeoTek Energy, LLC’s TDPS offers an opportunity to change the geothermal power industry dynamics.

  18. Hot Topics! Heat Pumps and Geothermal Energy

    ERIC Educational Resources Information Center

    Roman, Harry T.

    2009-01-01

    The recent rapid rises in the cost of energy has significantly increased interest in alternative energy sources. The author discusses the underlying principles of heat pumps and geothermal energy. Related activities for technology education students are included.

  19. Fundamentals of heat measurement. [heat flux transducers

    NASA Technical Reports Server (NTRS)

    Gerashchenko, O. A.

    1979-01-01

    Various methods and devices for obtaining experimental data on heat flux density over wide ranges of temperature and pressure are examined. Laboratory tests and device fabrication details are supplemented by theoretical analyses of heat-conduction and thermoelectric effects, providing design guidelines and information relevant to further research and development. A theory defining the measure of correspondence between transducer signal and the measured heat flux is established for individual (isolated) heat flux transducers subject to space and time-dependent loading. An analysis of the properties of stacked (series-connected) transducers of various types (sandwich-type, plane, and spiral) is used to derive a similarity theory providing general governing relationships. The transducers examined are used in 36 types of derivative devices involving direct heat loss measurements, heat conduction studies, radiation pyrometry, calorimetry in medicine and industry and nuclear reactor dosimetry.

  20. Geothermal direct-heat utilization assistance

    NASA Astrophysics Data System (ADS)

    1993-11-01

    This report consists of brief summaries of the activities of the Geo-Heat Center during the report period. Technical assistance was given to requests from 20 states in the following applications: space and district heating; geothermal heat pumps; greenhouses; aquaculture; industrial plants; electric power; resource/well; equipment; and resort/spa. Research and development activities progressed on compilation of data on low temperature resources and evaluation of groundwater versus ground-coupled heat pumps. Also summarized are technology transfer activities and geothermal progress monitoring activities.

  1. Geothermal direct-heat utilization assistance

    NASA Astrophysics Data System (ADS)

    1994-07-01

    The Geo-Heat Center provides technical assistance on geothermal direct heat applications to developers, consultants and the public which could include: data and information on low-temperature (less than 1500 C) resources, space and district heating, geothermal heat pumps, greenhouses, aquaculture, industrial processes and other technologies. This assistance could include preliminary engineering feasibility studies, review of direct-use project plans, assistance in project material and equipment selection, analysis and solutions of project operating problems, and information on resources and utilization. The following are brief descriptions of technical assistance provided during the second quarter of the program.

  2. High heat flux loop heat pipes

    NASA Technical Reports Server (NTRS)

    North, Mark T.; Sarraf, David B.; Rosenfeld, John H.; Maidanik, Yuri F.; Vershinin, Sergey

    1997-01-01

    Loop heat pipes (LHPs) can transport very large thermal power loads over long distances, through flexible, small diameter tubes against gravitational heads. In order to overcome the evaporator limit of LHPs, which is of about 0.07 MW/sq m, work was carried out to improve the efficiency by threefold to tenfold. The vapor passage geometry for the high heat flux conditions is shown. A bidisperse wick material within the circumferential vapor passages was used. Along with heat flux enhancement, several underlying issues were demonstrated, including the fabrication of bidisperse powder with controlled properties and the fabrication of a device geometry capable of replacing vapor passages with bidisperse powder.

  3. Heat flux limiting sleeves

    DOEpatents

    Harris, William G.

    1985-01-01

    A heat limiting tubular sleeve extending over only a portion of a tube having a generally uniform outside diameter, the sleeve being open on both ends, having one end thereof larger in diameter than the other end thereof and having a wall thickness which decreases in the same direction as the diameter of the sleeve decreases so that the heat transfer through the sleeve and tube is less adjacent the large diameter end of the sleeve than adjacent the other end thereof.

  4. Town of Pagosa Springs geothermal heating system

    SciTech Connect

    Garcia, M.B.

    1997-08-01

    The Town of Pagosa Springs has owned and operated a geothermal heating system since December 1982 to provide geothermal heating during the fall, winter and spring to customers in this small mountain town. Pagosa Springs is located in Archuleta County, Colorado in the southwestern corner of the State. The Town, nestled in majestic mountains, including the Continental Divide to the north and east, has an elevation of 7,150 feet. The use of geothermal water in the immediate area, however, dates back to the 1800`s, with the use of Ute Bands and the Navajo Nation and later by the U.S. Calvery in the 1880`s (Lieutenant McCauley, 1878). The Pagosa area geothermal water has been reported to have healing and therapeutic qualities.

  5. A geothermal heat pump for every home?

    NASA Astrophysics Data System (ADS)

    White, M. Catherine

    Witnesses representing government, industry, and education requested increased federal funding to explore and utilize geothermal resources at a House Subcommittee on Environment hearing July 30. Citing the minimal environmental impact, low cost, and abundance of geothermal energy, and the chance to cut dependence on fossil fuels, the witnesses discussed the geothermal heat pump (GHP)—one of the energy source's most promising applications, according to testimony. The GHP has the capacity to help utility companies manage increased demand for electricity, and its small scale—one to a home—makes it highly accessible.

  6. Direct heat utilization of geothermal resources

    SciTech Connect

    Lund, J.W.

    1996-08-01

    Direct or non-electric utilization of geothermal energy refers to the immediate use of the heat energy rather than to its conversion to some other form such as electrical energy. The primary forms of direct use include swimming, bathing and balneology (therapeutic use), space heating and cooling including district heating, agriculture (mainly greenhouse heating and some animal husbandry), aquaculture (mainly fish pond and raceway heating), industrial processes, and heat pumps (for both heating and cooling). In general, the geothermal fluid temperatures required for direct heat use are lower than those for economic electric power generation. Most direct use applications use geothermal fluids in the low-to-moderate temperature range between 50{degrees} and 150{degrees}C, and in general, the reservoir can be exploited by conventional water well drilling equipment. Low-temperature systems are also more widespread than high-temperature systems (above 150{degrees}C), so they are more likely to be located near potential users. In the US, for example, of the 1,350 known or identified geothermal systems, 5% are above 150{degrees}C, and 85% are below 90{degrees}C (Muffler, 1979). In fact, almost every country in the world has some low-temperature systems; while, only a few have accessible high-temperature systems.

  7. High heat flux loop heat pipes

    NASA Astrophysics Data System (ADS)

    North, Mark T.; Sarraf, David B.; Rosenfeld, John H.; Maidanik, Yuri F.; Vershinin, Sergey

    1997-01-01

    Loop Heat Pipes (LHPs) can transport very large thermal power loads, over long distances, through flexible, small diameter tubes and against high gravitational heads. While recent LHPs have transported as much as 1500 W, the peak heat flux through a LHP's evaporator has been limited to about 0.07 MW/m2. This limitation is due to the arrangement of vapor passages next to the heat load which is one of the conditions necessary to ensure self priming of the device. This paper describes work aimed at raising this limit by threefold to tenfold. Two approaches were pursued. One optimized the vapor passage geometry for the high heat flux conditions. The geometry improved the heat flow into the wick and working fluid. This approach also employed a finer pored wick to support higher vapor flow losses. The second approach used a bidisperse wick material within the circumferential vapor passages. The bidisperse material increased the thermal conductivity and the evaporative surface area in the region of highest heat flux, while providing a flow path for the vapor. Proof-of-concept devices were fabricated and tested for each approach. Both devices operated as designed and both demonstrated operation at a heat flux of 0.70 MW/m2. This performance exceeded the known state of the art by a factor of more than six for both conventional heat pipes and for loop heat pipes using ammonia. In addition, the bidisperse-wick device demonstrated boiling heat transfer coefficients up to 100,000 W/m2.K, and the fine pored device demonstrated an orientation independence with its performance essentially unaffected by whether its evaporator was positioned above, below or level with the condenser.

  8. Heat pump assisted geothermal heating system for Felix Spa, Romania

    SciTech Connect

    Rosca, Marcel; Maghiar, Teodor

    1996-01-24

    The paper presents a pre-feasibility type study of a proposed heat pump assisted geothermal heating system for an average hotel in Felix Spa, Romania. After a brief presentation of the geothermal reservoir, the paper gives the methodology and the results of the technical and economical calculations. The technical and economical viability of the proposed system is discussed in detail in the final part of the paper.

  9. Geothermal direct heat applications program summary

    SciTech Connect

    1980-04-01

    The use of geothermal energy for direct heat purposes by the private sector within the US has been quite limited to date. However, there is a large potential market for thermal energy in such areas as industrial processing, agribusiness, and space/water heating of commercial and residential buildings. Technical and economic information is needed to assist in identifying prospective direct heat users and to match their energy needs to specific geothermal reservoirs. Technological uncertainties and associated economic risks can influence the user's perception of profitability to the point of limiting private investment in geothermal direct applications. To stimulate development in the direct heat area, the Department of Energy, Division of Geothermal Energy, issued two Program Opportunity Notices (PON's). These solicitations are part of DOE's national geothermal energy program plan, which has as its goal the near-term commercialization by the private sector of hydrothermal resources. Encouragement is being given to the private sector by DOE cost-sharing a portion of the front-end financial risk in a limited number of demonstration projects. The twenty-two projects summarized herein are direct results of the PON solicitations.

  10. Heat flux solarimeter

    SciTech Connect

    Sartarelli, A.; Vera, S.; Cyrulies, E.; Echarri, R.; Samson, I.

    2010-12-15

    The solarimeter presented in this work is easy to assemble. It is calibrated and its performance is validated by means of Hottel's method. Finally, the curves obtained with this solarimeter are compared to the ones obtained with a commercial solarimeter. This device is based on the evaluation of the heat flow in a metal rod. In consequence, measurements are not affected by ambient temperature variations. On the other hand, there is a linear relationship between the temperatures measured at the rod ends and the incident radiation, as can be concluded both from the theory of its operation and the calibration lines obtained. The results obtained from the global irradiance measurements in the area of Los Polvorines (Buenos Aires Province), together with a preliminary evaluation of the solarimeter's response time, are presented in this work. (author)

  11. Geothermal heat pump system assisted by geothermal hot spring

    NASA Astrophysics Data System (ADS)

    Nakagawa, M.; Koizumi, Y.

    2016-01-01

    The authors propose a hybrid geothermal heat pump system that could cool buildings in summer and melt snow on the pedestrian sidewalks in winter, utilizing cold mine water and hot spring water. In the proposed system, mine water would be used as cold thermal energy storage, and the heat from the hot spring after its commercial use would be used to melt snow for a certain section of sidewalks. Neither of these sources is viable for direct use application of geothermal resources, however, they become contributing energy factors without producing any greenhouse gases. To assess the feasibility of the proposed system, a series of temperature measurements in the Edgar Mine (Colorado School of Mines' experimental mine) in Idaho Springs, Colorado, were first conducted, and heat/mass transfer analyses of geothermal hot spring water was carried out. The result of the temperature measurements proved that the temperature of Edgar Mine would be low enough to store cold groundwater for use in summer. The heat loss of the hot spring water during its transportation was also calculated, and the heat requirement for snow melt was compared with the heat available from the hot spring water. It was concluded that the heat supply in the proposed usage of hot spring water was insufficient to melt the snow for the entire area that was initially proposed. This feasibility study should serve as an example of "local consumption of locally available energy". If communities start harnessing economically viable local energy in a responsible manner, there will be a foundation upon which to build a sustainable community.

  12. Hoosac tunnel geothermal heat source. Final report

    SciTech Connect

    Not Available

    1982-06-10

    The Hoosac Rail Tunnel has been analyzed as a central element in a district heating system for the City of North Adams. The tunnel has been viewed as a collector of the earth's geothermal heat and a seasonal heat storage facility with heat piped to the tunnel in summer from existing facilities at a distance. Heated fluid would be transported in winter from the tunnel to users who would boost the temperature with individual heat pumps. It was concluded the tunnel is a poor source of geothermal heat. The maximum extractable energy is only 2200 million BTU (20000 gallons of oil) at 58/sup 0/F. The tunnel is a poor heat storage facility. The rock conductivity is so high that 75% of the heat injected would escape into the mountain before it could be recaptured for use. A low temperature system, with individual heat pumps for temperature boost could be economically attractive if a low cost fuel (byproduct, solid waste, cogeneration) or a cost effective seasonal heat storage were available.

  13. Convective heat transport in geothermal systems

    SciTech Connect

    Lippmann, M.J.; Bodvarsson, G.S.

    1986-08-01

    Most geothermal systems under exploitation for direct use or electrical power production are of the hydrothermal type, where heat is transferred essentially by convection in the reservoir, conduction being secondary. In geothermal systems, buoyancy effects are generally important, but often the fluid and heat flow patterns are largely controlled by geologic features (e.g., faults, fractures, continuity of layers) and location of recharge and discharge zones. During exploitation, these flow patterns can drastically change in response to pressure and temperature declines, and changes in recharge/discharge patterns. Convective circulation models of several geothermal systems, before and after start of fluid production, are described, with emphasis on different characteristics of the systems and the effects of exploitation on their evolution. Convective heat transport in geothermal fields is discussed, taking into consideration (1) major geologic features; (2) temperature-dependent rock and fluid properties; (3) fracture- versus porous-medium characteristics; (4) single- versus two-phase reservoir systems; and (5) the presence of noncondensible gases.

  14. Blueprint for financing geothermal district heating in California

    SciTech Connect

    Grattan, J.P.; Hansen, D.P.

    1981-03-01

    The current legal and investment climate surrounding geothermal development is depicted. Changes that would make the climate more favorable to direct heat geothermal development are recommended. The Boise, Susanville, and Brady Hot Springs projects are analyzed. (MHR)

  15. Automated Heat-Flux-Calibration Facility

    NASA Technical Reports Server (NTRS)

    Liebert, Curt H.; Weikle, Donald H.

    1989-01-01

    Computer control speeds operation of equipment and processing of measurements. New heat-flux-calibration facility developed at Lewis Research Center. Used for fast-transient heat-transfer testing, durability testing, and calibration of heat-flux gauges. Calibrations performed at constant or transient heat fluxes ranging from 1 to 6 MW/m2 and at temperatures ranging from 80 K to melting temperatures of most materials. Facility developed because there is need to build and calibrate very-small heat-flux gauges for Space Shuttle main engine (SSME).Includes lamp head attached to side of service module, an argon-gas-recirculation module, reflector, heat exchanger, and high-speed positioning system. This type of automated heat-flux calibration facility installed in industrial plants for onsite calibration of heat-flux gauges measuring fluxes of heat in advanced gas-turbine and rocket engines.

  16. Latent heat sink in soil heat flux measurements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The surface energy balance includes a term for soil heat flux. Soil heat flux is difficult to measure because it includes conduction and convection heat transfer processes. Accurate representation of soil heat flux is an important consideration in many modeling and measurement applications. Yet, the...

  17. Alternative institutional vehicles for geothermal district heating

    SciTech Connect

    Bressler, S.; Gardner, T.C.; King, D.; Nimmons, J.T.

    1980-06-01

    The attributes of various institutional entities which might participate in various phases of geothermal heating applications are described. Public entities considered include cities, counties, and special districts. Private entities discussed include cooperative organizations and non-member-owned private enterprises. The powers, authority and manner of operation of each of the institutional entities are reviewed. Some of the public utility regulatory implications which may affect choices among available alternatives are considered. (MHR)

  18. Sensitivity of contemporary sea level trends in a global ocean state estimate to effects of geothermal fluxes

    NASA Astrophysics Data System (ADS)

    Piecuch, Christopher G.; Heimbach, Patrick; Ponte, Rui M.; Forget, Gaël

    2015-12-01

    Geothermal fluxes constitute a sizable fraction of the present-day Earth net radiative imbalance and corresponding ocean heat uptake. Model simulations of contemporary sea level that impose a geothermal flux boundary condition are becoming increasingly common. To quantify the impact of geothermal fluxes on model estimates of contemporary (1993-2010) sea level changes, two ocean circulation model experiments are compared. The two simulations are based on a global ocean state estimate, produced by the Estimating the Circulation and Climate of the Ocean (ECCO) consortium, and differ only with regard to whether geothermal forcing is applied as a boundary condition. Geothermal forcing raises the global-mean sea level trend by 0.11 mm yr-1 in the perturbation experiment by suppressing a cooling trend present in the baseline solution below 2000 m. The imposed forcing also affects regional sea level trends. The Southern Ocean is particularly sensitive. In this region, anomalous heat redistribution due to geothermal fluxes results in steric height trends of up to ± 1 mm yr-1 in the perturbation experiment relative to the baseline simulation. Analysis of a passive tracer experiment suggests that the geothermal input itself is transported by horizontal diffusion, resulting in more thermal expansion over deeper ocean basins. Thermal expansion in the perturbation simulation gives rise to bottom pressure increase over shallower regions and decrease over deeper areas relative to the baseline run, consistent with mass redistribution expected for deep ocean warming. These results elucidate the influence of geothermal fluxes on sea level rise and global heat budgets in model simulations of contemporary ocean circulation and climate.

  19. Geothermal Direct Heat Applications Program Summary

    SciTech Connect

    1981-09-25

    Because of the undefined risk in the development and use of geothermal energy as a thermal energy source, the Department of Energy Division of Geothermal Energy solicited competitive proposals for field experiments in the direct use of geothermal energy. Twenty-two proposals were selected for cost-shared funding with one additional project co-funded by the State of New Mexico. As expected, the critical parameter was developing a viable resource. So far, of the twenty resources drilled, fourteen have proved to be useful resources. These are: Boise, Idaho; Elko heating Company in Nevada; Pagosa Springs, Colorado; Philip School, Philip, South Dakota; St. Mary's Hospital, Pierre, South Dakota; Utah Roses near Salt Lake City; Utah State Prison, Utah; Warm Springs State Hospital, Montana; T-H-S Hospital, Marlin, Texas; Aquafarms International in the Cochella Valley, California; Klamath County YMCA and Klamath Falls in Oregon; Susanville, California and Monroe, utah. Monroe's 164 F and 600 gpm peak flow was inadequate for the planned project, but is expected to be used in a private development. Three wells encountered a resource insufficient for an economical project. These were Madison County at Rexburg, Idaho; Ore-Ida Foods at Ontario, Oregon and Holly Sugar at Brawley, California. Three projects have yet to confirm their resource. The Navarro College well in Corsicana, Texas is being tested; the Reno, Moana, Nevada well is being drilled and the El Centro, California well is scheduled to be drilled in January 1982. The agribusiness project at Kelly Hot Springs was terminated because a significant archeological find was encountered at the proposed site. The Diamond Ring Ranch in South Dakota, and the additional project, Carrie Tingley Hospital in Truth or Consequences, New Mexico both used existing wells. The projects that encountered viable resources have proceeded to design, construct, and in the most advanced projects, to operate geothermal systems for district

  20. Geothermal direct heat applications program summary

    SciTech Connect

    1982-08-01

    In 1978, the Department of Energy Division of Geothermal and Hydropower Technologies initiated a program to accelerate the direct use of geothermal energy, in which 23 projects were selected. The projects, all in the western part of the US, cover the use of geothermal energy for space conditioning (heating and cooling) and agriculture (aquaculture and greenhouses). Initially, two projects were slated for industrial processing; however, because of lack of geothermal resources, these projects were terminated. Of the 23 projects, seven were successfully completed, ten are scheduled for completion by the end of 1983, and six were terminated for lack of resources. Each of the projects is being documented from its inception through planning, drilling, and resource confirmation, design, construction, and one year of monitoring. The information is being collected, evaluated, and will be reported. Several reports will be produced, including detailed topical reports on economics, institutional and regulatory problems, engineering, and a summary final report. To monitor progress and provide a forum for exchange of information while the program is progressing, semiannual or annual review meetings have been held with all project directors and lead engineers for the past four years. This is the sixth meeting in that series. Several of the projects which have been terminated are not included this year. Overall, the program has been very successful. Valuable information has been gathered. problems have been encountered and resolved concerning technical, regulatory, and institutional constraints. Most projects have been proven to be economical with acceptable pay-back periods. Although some technical problems have emerged, they were resolved with existing off-the-shelf technologies and equipment. The risks involved in drilling for the resource, the regulatory constraints, the high cost of finance, and large front-end cost remain the key obstacles to the broad development of

  1. Minnesota Heat Flow and Geothermal Potential

    NASA Astrophysics Data System (ADS)

    Gosnold, W. D.; Crowell, J.; Bubach, B.; Wahl, P.; Crowell, A. M.; Mcdonald, M. R.

    2011-12-01

    Radiogenic heat production, bedrock geology, gravity, magnetics, and heat flow were combined to study heat flow and geothermal energy potential in Minnesota. Heat production was determined from one-hundred 800 kg samples collected at outcrops and from drill cores by gamma ray spectrometry. Small splits of the samples were also analyzed by chemical methods for K, U, and Th. Heat production averaged 2.6 W m-1 K-1 ± 2.0 for 42 felsic samples and 0.9 W m-1 K-1 ± 0.6 for 58 mafic samples. Areal variation in heat production measured with a portable gamma ray spectrometer was compared to bedrock geology and gravity and magnetic anomaly patterns. Gravity lows and magnetic highs correlate with higher heat production and vice versa. Prior to this study heat flow was reported for only four borehole sites in Minnesota. Those sites were located in Keweenawan mafic rocks of the mid-continent rift and heat flow values averaged 39 ± 6 mW m-2. These low heat flows are consistent with a heat flow study conducted in Lake Superior that showed a trough of low heat flow (19.2 - 41.0 mW m-2) along the northern edge of the lake. Thirty-one new heat flow determinations in the mafic rocks obtained from borehole temperature measurements in mining holes average (34.1 mW m-2 ± 1.9 mW m-2). However, paleoclimate signals evident in the temperature vs. depth profiles indicate that the temperature gradients are at least 27 percent low and heat flow is likely 46.7 mW m-2. Based on a reduced heat flow of 32 mW m-2 and a depth parameter of 10 km, the heat flow heat production relation yields a heat flow value of 58 mW m-2 in the felsic regions in Minnesota. These heat flow values suggest that EGS with a binary power plant would be achievable in the felsic regions.

  2. Dual Active Surface Heat Flux Gage Probe

    NASA Technical Reports Server (NTRS)

    Liebert, Curt H.; Kolodziej, Paul

    1995-01-01

    A unique plug-type heat flux gage probe was tested in the NASA Ames Research Center 2x9 turbulent flow duct facility. The probe was fabricated by welding a miniature dual active surface heat flux gage body to the end of a hollow metal cylindrical bolt containing a metal inner tube. Cooling air flows through the inner tube, impinges onto the back of the gage body and then flows out through the annulus formed between the inner tube and the hollow bolt wall. Heat flux was generated in the duct facility with a Huels arc heater. The duct had a rectangular cross section and one wall was fabricated from 2.54 centimeter thick thermal insulation rigid surface material mounted onto an aluminum plate. To measure heat flux, the probe was inserted through the plate and insulating materials with the from of the gage located flush with the hot gas-side insulation surface. Absorbed heat fluxes measured with the probe were compared with absorbed heat fluxes measured with six water-cooled reference calorimeters. These calorimeters were located in a water-cooled metal duct wall which was located across from the probe position. Correspondence of transient and steady heat fluxes measured with the reference calorimeters and heat flux gage probe was generally within a satisfactory plus or minus 10 percent. This good correspondence was achieved even though the much cooler probe caused a large surface temperature disruption of 1000K between the metal gage and the insulation. However, this temperature disruption did not seriously effect the accuracy of the heat flux measurement. A current application for dual active surface heat flux gages is for transient and steady absorbed heat flux, surface temperature and heat transfer coefficient measurements on the surface of an oxidizer turbine inlet deflector operating in a space shuttle test bed engine.

  3. Pyrolytic graphite gauge for measuring heat flux

    NASA Technical Reports Server (NTRS)

    Bunker, Robert C. (Inventor); Ewing, Mark E. (Inventor); Shipley, John L. (Inventor)

    2002-01-01

    A gauge for measuring heat flux, especially heat flux encountered in a high temperature environment, is provided. The gauge includes at least one thermocouple and an anisotropic pyrolytic graphite body that covers at least part of, and optionally encases the thermocouple. Heat flux is incident on the anisotropic pyrolytic graphite body by arranging the gauge so that the gauge surface on which convective and radiative fluxes are incident is perpendicular to the basal planes of the pyrolytic graphite. The conductivity of the pyrolytic graphite permits energy, transferred into the pyrolytic graphite body in the form of heat flux on the incident (or facing) surface, to be quickly distributed through the entire pyrolytic graphite body, resulting in small substantially instantaneous temperature gradients. Temperature changes to the body can thereby be measured by the thermocouple, and reduced to quantify the heat flux incident to the body.

  4. Numerical modeling of cold magmatic CO2 flux measurements for the exploration of hidden geothermal systems

    NASA Astrophysics Data System (ADS)

    Peiffer, Loïc.; Wanner, Christoph; Pan, Lehua

    2015-10-01

    The most accepted conceptual model to explain surface degassing of cold magmatic CO2 in volcanic-geothermal systems involves the presence of a gas reservoir. In this study, numerical simulations using the TOUGH2-ECO2N V2.0 package are performed to get quantitative insights into how cold CO2 soil flux measurements are related to reservoir and fluid properties. Although the modeling is based on flux data measured at a specific geothermal site, the Acoculco caldera (Mexico), some general insights have been gained. Both the CO2 fluxes at the surface and the depth at which CO2 exsolves are highly sensitive to the dissolved CO2 content of the deep fluid. If CO2 mainly exsolves above the reservoir within a fracture zone, the surface CO2 fluxes are not sensitive to the reservoir size but depend on the CO2 dissolved content and the rock permeability. For gas exsolution below the top of the reservoir, surface CO2 fluxes also depend on the gas saturation of the deep fluid as well as the reservoir size. The absence of thermal anomalies at the surface is mainly a consequence of the low enthalpy of CO2. The heat carried by CO2 is efficiently cooled down by heat conduction and to a certain extent by isoenthalpic volume expansion depending on the temperature gradient. Thermal anomalies occur at higher CO2 fluxes (>37,000 g m-2 d-1) when the heat flux of the rising CO2 is not balanced anymore. Finally, specific results are obtained for the Acoculco area (reservoir depth, CO2 dissolved content, and gas saturation state).

  5. New geothermal heat extraction process to deliver clean power generation

    ScienceCinema

    Pete McGrail

    2016-07-12

    A new method for capturing significantly more heat from low-temperature geothermal resources holds promise for generating virtually pollution-free electrical energy. Scientists at the Department of Energys Pacific Northwest National Laboratory will determine if their innovative approach can safely and economically extract and convert heat from vast untapped geothermal resources. The goal is to enable power generation from low-temperature geothermal resources at an economical cost. In addition to being a clean energy source without any greenhouse gas emissions, geothermal is also a steady and dependable source of power.

  6. Hawaiian direct-heat grants encourage geothermal creativity

    SciTech Connect

    Beck, A.G. )

    1988-12-01

    The Hawaiian Community Geothermal Technology Program is unique. Under its auspices, heat and other by-products of Hawaii's high-temperature HGP-A geothermal well and power plant are not wasted. Instead, they form the backbone of a direct-heat grant program that reaches into the local community and encourages community members to develop creative uses for geothermal energy. A by-product of this approach is a broadened local base of support for geothermal energy development. With the experimental and precommercial work completed, most of the original grantees are looking for ways to continue their projects on a commercial scale by studying the economics of using geothermal heat in a full-scale business and researching potential markets. A geothermal mini-park may be built near the research center. In 1988, a second round of projects was funded under the program. The five new projects are: Geothermal Aquaculture Project - an experiment with low-cost propagation of catfish species in geothermally heated tanks with a biofilter; Media Steam Sterilization and Drying - an application of raw geothermal steam to shredded, locally-available materials such as coconut husks, which would be used as certified nursery growing media; Bottom-Heating System Using Geothermal Power for Propagation - a continuation of Leilani Foliage's project from the first round of grants, focusing on new species of ornamental palms; Silica Bronze - the use of geothermal silica as a refractory material in casting bronze artwork; and Electro-deposition of Minerals in Geothermal Brine - the nature and possible utility of minerals deposited from the hot fluid.

  7. Efficiency improvements by geothermal heat integration in a lignocellulosic biorefinery.

    PubMed

    Sohel, M Imroz; Jack, Michael

    2010-12-01

    In an integrated geothermal biorefinery, low-grade geothermal heat is used as process heat to allow the co-products of biofuel production to become available for higher-value uses. In this paper we consider integrating geothermal heat into a biochemical lignocellulosic biorefinery so that the lignin-enriched residue can be used either as a feedstock for chemicals and materials or for on-site electricity generation. Depending on the relative economic value of these two uses, we can maximize revenue of a biorefinery by judicious distribution of the lignin-enriched residue between these two options. We quantify the performance improvement from integrating geothermal energy for an optimized system. We then use a thermodynamic argument to show that integrating geothermal heat into a biorefinery represents an improvement in overall resource utilization efficiency in all cases considered. Finally, possible future technologies for electricity generation are considered which could improve this efficiency further.

  8. Heat flux viscosity in collisional magnetized plasmas

    SciTech Connect

    Liu, C.; Fox, W.; Bhattacharjee, A.

    2015-05-15

    Momentum transport in collisional magnetized plasmas due to gradients in the heat flux, a “heat flux viscosity,” is demonstrated. Even though no net particle flux is associated with a heat flux, in a plasma there can still be momentum transport owing to the velocity dependence of the Coulomb collision frequency, analogous to the thermal force. This heat-flux viscosity may play an important role in numerous plasma environments, in particular, in strongly driven high-energy-density plasma, where strong heat flux can dominate over ordinary plasma flows. The heat flux viscosity can influence the dynamics of the magnetic field in plasmas through the generalized Ohm's law and may therefore play an important role as a dissipation mechanism allowing magnetic field line reconnection. The heat flux viscosity is calculated directly using the finite-difference method of Epperlein and Haines [Phys. Fluids 29, 1029 (1986)], which is shown to be more accurate than Braginskii's method [S. I. Braginskii, Rev. Plasma Phys. 1, 205 (1965)], and confirmed with one-dimensional collisional particle-in-cell simulations. The resulting transport coefficients are tabulated for ease of application.

  9. Heat flux viscosity in collisional magnetized plasmas

    NASA Astrophysics Data System (ADS)

    Liu, C.; Fox, W.; Bhattacharjee, A.

    2015-05-01

    Momentum transport in collisional magnetized plasmas due to gradients in the heat flux, a "heat flux viscosity," is demonstrated. Even though no net particle flux is associated with a heat flux, in a plasma there can still be momentum transport owing to the velocity dependence of the Coulomb collision frequency, analogous to the thermal force. This heat-flux viscosity may play an important role in numerous plasma environments, in particular, in strongly driven high-energy-density plasma, where strong heat flux can dominate over ordinary plasma flows. The heat flux viscosity can influence the dynamics of the magnetic field in plasmas through the generalized Ohm's law and may therefore play an important role as a dissipation mechanism allowing magnetic field line reconnection. The heat flux viscosity is calculated directly using the finite-difference method of Epperlein and Haines [Phys. Fluids 29, 1029 (1986)], which is shown to be more accurate than Braginskii's method [S. I. Braginskii, Rev. Plasma Phys. 1, 205 (1965)], and confirmed with one-dimensional collisional particle-in-cell simulations. The resulting transport coefficients are tabulated for ease of application.

  10. Comparison of the high temperature heat flux sensor to traditional heat flux gages under high heat flux conditions.

    SciTech Connect

    Blanchat, Thomas K.; Hanks, Charles R.

    2013-04-01

    Four types of heat flux gages (Gardon, Schmidt-Boelter, Directional Flame Temperature, and High Temperature Heat Flux Sensor) were assessed and compared under flux conditions ranging between 100-1000 kW/m2, such as those seen in hydrocarbon fire or propellant fire conditions. Short duration step and pulse boundary conditions were imposed using a six-panel cylindrical array of high-temperature tungsten lamps. Overall, agreement between all gages was acceptable for the pulse tests and also for the step tests. However, repeated tests with the HTHFS with relatively long durations at temperatures approaching 1000ÀC showed a substantial decrease (10-25%) in heat flux subsequent to the initial test, likely due to the mounting technique. New HTHFS gages have been ordered to allow additional tests to determine the cause of the flux reduction.

  11. Geothermal direct-heat utilization assistance. Quarterly project progress report, July 1995--September 1995

    SciTech Connect

    Lienau, P.

    1995-12-01

    The report summarizes geothermal technical assistance, R&D and technology transfer activities of the Geo-Heat Center at Oregon Institute of Technology for the fourth quarter of FY-95. It describes 80 contacts with parties during this period related to technical assistance with geothermal direct heat projects. Areas dealt with include geothermal heat pumps, space heating, greenhouses, aquaculture, equipment and resources. Research activities are summarized on low-temperature resource assessment, geothermal energy cost evaluation and marketing strategy for geothermal district heating. Outreach activities include the publication of a geothermal direct use Bulletin, dissemination of information, geothermal library, technical papers and seminars, and progress monitor reports on geothermal resources and utilization.

  12. Fabrication of Thin Film Heat Flux Sensors

    NASA Technical Reports Server (NTRS)

    Will, Herbert A.

    1992-01-01

    Prototype thin film heat flux sensors have been constructed and tested. The sensors can be applied to propulsion system materials and components. The sensors can provide steady state and fast transient heat flux information. Fabrication of the sensor does not require any matching of the mounting surface. Heat flux is proportional to the temperature difference across the upper and lower surfaces of an insulation material. The sensor consists of an array of thermocouples on the upper and lower surfaces of a thin insulating layer. The thermocouples for the sensor are connected in a thermopile arrangement. A 100 thermocouple pair heat flux sensor has been fabricated on silicon wafers. The sensor produced an output voltage of 200-400 microvolts when exposed to a hot air heat gun. A 20 element thermocouple pair heat flux sensor has been fabricated on aluminum oxide sheet. Thermocouples are Pt-Pt/Rh with silicon dioxide as the insulating material. This sensor produced an output of 28 microvolts when exposed to the radiation of a furnace operating at 1000 C. Work is also underway to put this type of heat flux sensor on metal surfaces.

  13. Heat flux microsensor measurements and calibrations

    NASA Technical Reports Server (NTRS)

    Terrell, James P.; Hager, Jon M.; Onishi, Shinzo; Diller, Thomas E.

    1992-01-01

    A new thin-film heat flux gage has been fabricated specifically for severe high temperature operation using platinum and platinum-10 percent rhodium for the thermocouple elements. Radiation calibrations of this gage were performed at the AEDC facility over the available heat flux range (approx. 1.0 - 1,000 W/cu cm). The gage output was linear with heat flux with a slight increase in sensitivity with increasing surface temperature. Survivability of gages was demonstrated in quench tests from 500 C into liquid nitrogen. Successful operation of gages to surface temperatures of 750 C has been achieved. No additional cooling of the gages is required because the gages are always at the same temperature as the substrate material. A video of oxyacetylene flame tests with real-time heat flux and temperature output is available.

  14. Geothermal direct-heat utilization assistance: Quarterly project progress report, January--March 1995

    SciTech Connect

    1995-05-01

    The report summarizes geothermal activities of the Geo-Heat Center at Oregon Institute of Technology for the second quarter of FY-95. It describes 92 contacts with parties during this period related to technical assistance with geothermal direct heat projects. Areas dealt with include geothermal heat pumps, space heating, greenhouses, aquaculture, resources and equipment. Research activities are summarized on geothermal energy cost evaluation, low temperature resource assessment and ground-source heat pump case studies and utility programs. Outreach activities include the publication of a geothermal direct heat Bulletin, dissemination of information, geothermal library, and progress monitor reports on geothermal resources and utilization.

  15. Critical heat flux test apparatus

    DOEpatents

    Welsh, Robert E.; Doman, Marvin J.; Wilson, Edward C.

    1992-01-01

    An apparatus for testing, in situ, highly irradiated specimens at high temperature transients is provided. A specimen, which has a thermocouple device attached thereto, is manipulated into test position in a sealed quartz heating tube by a robot. An induction coil around a heating portion of the tube is powered by a radio frequency generator to heat the specimen. Sensors are connected to monitor the temperatures of the specimen and the induction coil. A quench chamber is located below the heating portion to permit rapid cooling of the specimen which is moved into this quench chamber once it is heated to a critical temperature. A vacuum pump is connected to the apparatus to collect any released fission gases which are analyzed at a remote location.

  16. Geothermal heating for the Arizona Environmental Research Laboratory greenhouses

    SciTech Connect

    White, D.H.; Goldstone, L.A.

    1982-08-01

    A preliminary study of the technical and economic feasibility of installing a retrofit geothermal heating system is analyzed for the Environmental Research Laboratory Farms greenhouse facility located in Tucson, Arizona. The facility consists of 10.6 acres of greenhouse area, of which 7.4 acres are currently operational. Natural gas or diesel fuel are presently used for heating. The maximum heating load is estimated to be 28,620,000 Btu/hr. Average annual heating energy consumption between 1974 and 1979 was 35,684 million But/year for 7.4 acres of greenhouse, costing an estimated $96,703 at 1981 natural gas prices. Two 2500 foot geothermal production wells are required, each capable of producing 1500 gpm of 130{sup 0}F water. The geothermal water is expected to contain 500 ppM total dissolved solids. Total estimated capital cost for installing the system is $902,946. The expected first year geothermal energy cost savigs are estimated to be $58,920. A simple payback of 9.1 years is calculated and the project has a net present value of $961,751. Geothermal heat could be supplied at a cost of $5.39 per million Btu in the first year of operation. The project as herein presented is marginally economic. However, it became clear after the study that an attractive economic case could be made for providing about 50 to 60 percent of the required heating load as a base load using geothermal energy.

  17. Utah State Prison Space Heating with Geothermal Heat - Resource Assessment Report Crystal Hot Springs Geothermal Area

    SciTech Connect

    1981-12-01

    Reported herein is a summary of work conducted under the Resource Assessment Program-Task 2, for the Utah State Prison Geothermal Space Heating Project at Crystal Hot Springs, Draper, Utah. Assessment of the geothermal resource in and around the Utah State Prison property began in october of 1979 with an aeromagnetic and gravity survey. These tasks were designed to provide detailed subsurface structural information in the vicinity of the thermal springs so that an informed decision as to the locations of test and production holes could be made. The geophysical reconnaissance program provided the structural details needed to focus the test drilling program on the most promising production targets available to the State Prison. The subsequent drilling and well testing program was conducted to provide information to aid fin the siting and design of a production well and preliminary design activities. As part of the resource assessment portion of the Utah State Prison Geothermal Project, a program for periodic geophysical monitoring of the Crystal Hot Springs resource was developed. The program was designed to enable determination of baseline thermal, hydraulic, and chemical characteristics in the vicinity of Crystal Hot Springs prior to production and to provide a history of these characteristics during resource development.

  18. Update and assessment of geothermal economic models, geothermal fluid flow and heat distribution models, and geothermal data bases

    SciTech Connect

    Kenkeremath, D.

    1985-05-01

    Numerical simulation models and data bases that were developed for DOE as part of a number of geothermal programs have been assessed with respect to their overall stage of development and usefulness. This report combines three separate studies that focus attention upon: (1) economic models related to geothermal energy; (2) physical geothermal system models pertaining to thermal energy and the fluid medium; and (3) geothermal energy data bases. Computerized numerical models pertaining to the economics of extracting and utilizing geothermal energy have been summarized and catalogued with respect to their availability, utility and function. The 19 models that are discussed in detail were developed for use by geothermal operators, public utilities, and lending institutions who require a means to estimate the value of a given resource, total project costs, and the sensitivity of these values to specific variables. A number of the models are capable of economically assessing engineering aspects of geothermal projects. Computerized simulations of heat distribution and fluid flow have been assessed and are presented for ten models. Five of the models are identified as wellbore simulators and five are described as reservoir simulators. Each model is described in terms of its operational characteristics, input, output, and other pertinent attributes. Geothermal energy data bases are reviewed with respect to their current usefulness and availability. Summaries of eight data bases are provided in catalogue format, and an overall comparison of the elements of each data base is included.

  19. Ice-sheet driven enhancement of geothermal flux: preliminary model results

    NASA Astrophysics Data System (ADS)

    Stevens, N. T.; Parizek, B. R.; Alley, R. B.; Pollard, D.; Anandakrishnan, S.

    2013-12-01

    Previous observations in parts of West Antarctica and Greenland, including near the head of the Northeast Greenland Ice Stream, have indicated rapid basal melting, suggesting higher geothermal flux than typical for the expected geological setting. Growth and decay of ice sheets over ice-age cycles cause large and geologically rapid changes in loading and flexure beneath and nearby. Oscillating load will cause oscillating melt volume in deep rocks, and because melt extraction increases with melt volume more rapidly than linearly, ice-age cycling will tend to move melt upward. Melt motion may be greatly aided by fracturing promoted by flexural stresses from the varying ice sheets. Preliminary results from ice-sheet models coupled to lithosphere and asthenosphere will be presented, suggesting that ice-sheet changes may be affecting their basal heat flux.

  20. Economics of geothermal, solar, and conventional space heating

    NASA Astrophysics Data System (ADS)

    Fassbender, L. L.; Bloomster, C. H.; Price, B. A.

    1980-12-01

    With the recent price increases in imported oil and natural gas and the planned decontrol of domestic prices, geothermal and solar energy becomes competitive for residential space heating throughout most of the country. Geothermal energy could competitively provide about 40% of the national demand for space heat and domestic hot water (about 7 quads based on 1980 demands). Nearly all of the geothermal energy demand would be in high population density areas. Solar energy could competitively provide about 50% (about 9 quads) of the annual demand. Most of the solar energy demand would be concentrated in suburban and rural areas. Conventional energy should remain competitive for about 30% (about 5 quads) of the annual demand. Conventional energy demand would be concentrated in the South and as supplemental energy for solar/conventional systems. Geothermal solar, and conventional energy would be equally competitive for about 20% of the annual demand, which is why the individual market shares add to 120%.

  1. Heat-Flux Gage thermophosphor system

    SciTech Connect

    Tobin, K.W.

    1991-08-01

    This document describes the installation, hardware requirements, and application of the Heat-Flux Gage (Version 1.0) software package developed by the Oak Ridge National Laboratory, Applied Technology Division. The developed software is a single component of a thermographic phosphor-based temperature and heat-flux measurement system. The heat-flux transducer was developed by EG G Energy Measurements Systems and consists of a 1- by 1-in. polymethylpentene sheet coated on the front and back with a repeating thermographic phosphor pattern. The phosphor chosen for this application is gadolinium oxysulphide doped with terbium. This compound has a sensitive temperature response from 10 to 65.6{degree}C (50--150{degree}F) for the 415- and 490-nm spectral emission lines. 3 refs., 17 figs.

  2. Geothermal Direct-Heat Utilization Assistance - Final Report

    SciTech Connect

    J. W. Lund

    1999-07-14

    The Geo-Heat Center provided (1) direct-use technical assistance, (2) research, and (3) information dissemination on geothermal energy over an 8 1/2 year period. The center published a quarterly bulletin, developed a web site and maintained a technical library. Staff members made 145 oral presentations, published 170 technical papers, completed 28 applied research projects, and gave 108 tours of local geothermal installations to 500 persons.

  3. Geothermal Heat Pump Profitability in Energy Services

    SciTech Connect

    1997-11-01

    If geothermal heat pumps (GHPs) are to make a significant mark in the market, we believe that it will be through energy service pricing contracts offered by retailcos. The benefits of GHPs are ideally suited to energy service pricing (ESP) contractual arrangements; however, few retailcos are thoroughly familiar with the benefits of GHPs. Many of the same barriers that have prevented GHPs from reaching their full potential in the current market environment remain in place for retailcos. A lack of awareness, concerns over the actual efficiencies of GHPs, perceptions of extremely high first costs, unknown records for maintenance costs, etc. have all contributed to limited adoption of GHP technology. These same factors are of concern to retailcos as they contemplate long term customer contracts. The central focus of this project was the creation of models, using actual GHP operating data and the experience of seasoned professionals, to simulate the financial performance of GHPs in long-term ESP contracts versus the outcome using alternative equipment. We have chosen two case studies, which may be most indicative of target markets in the competitive marketplace: A new 37,000 square foot office building in Toronto, Ontario; we also modeled a similar building under the weather conditions of Orlando, Florida. An aggregated residential energy services project using the mass conversion of over 4,000 residential units at Ft. Polk, Louisiana. Our method of analyses involved estimating equipment and energy costs for both the base case and the GHP buildings. These costs are input in to a cash flow analysis financial model which calculates an after-tax cost for the base and GHP case. For each case study customers were assumed to receive a 5% savings over their base case utility bill. A sensitivity analysis was then conducted to determine how key variables affect the attractiveness of a GHP investment.

  4. Description and operation of Haakon School geothermal-heating system

    SciTech Connect

    Childs, F.W.; Kirol, L.D.; Sanders, R.D.; McLatchy, M.J.

    1983-10-01

    To encourage the development of hydrothermal energy, twenty-three demonstration projects were funded. The Haakon School project is one of twelve such projects. The geothermal direct-use heating system at the Haakon School complex in Philip, South Dakota is described and information gained during approximately three heating seasons of operation is presented.

  5. Geothermal heat, BAS controls: a capitol investment for Idaho

    SciTech Connect

    Not Available

    1985-11-01

    At the Capitol Mall in Boise, the old old problem of space heating has been solved by a marriage of old and new technologies: a geothermal heating system and a high-tech building automation system (BAS). The result is savings of more than $200,000 a year in natural gas costs.

  6. Comparing different land surface heat flux estimates

    NASA Astrophysics Data System (ADS)

    Tretkoff, Ernie

    2011-04-01

    Land surface heat fluxes are an important component of Earth's energy and water cycle, and quantifying these fluxes can help scientists better understand climate change. These heat fluxes are affected by factors such as cloud cover, precipitation, surface radiation, air temperature, and humidity. Different methods are used to estimate monthly mean land surface heat flux. To determine how well these different methods agree with one other, Jiménez et al. present a detailed global intercomparison of 12 such products for the period 1993-1995. Some of these products are based on combining global satellite-based data and physical formulations, while others come from atmospheric reanalysis and land surface models. The authors found that although there were some differences among the products, the products all captured the seasonality of the heat fluxes as well as the expected spatial distributions related to major climatic regimes and geographical features. Furthermore, the products correlate well with each other in general, in part due to large seasonable variability and the fact that some of the products use the same forcing data. (Journal of Geophysical Research-Atmospheres, doi:10.1029/2010JD014545, 2011)

  7. Heat flux sensors for infrared thermography in convective heat transfer.

    PubMed

    Carlomagno, Giovanni Maria; de Luca, Luigi; Cardone, Gennaro; Astarita, Tommaso

    2014-11-07

    This paper reviews the most dependable heat flux sensors, which can be used with InfraRed (IR) thermography to measure convective heat transfer coefficient distributions, and some of their applications performed by the authors' research group at the University of Naples Federico II. After recalling the basic principles that make IR thermography work, the various heat flux sensors to be used with it are presented and discussed, describing their capability to investigate complex thermo-fluid-dynamic flows. Several applications to streams, which range from natural convection to hypersonic flows, are also described.

  8. Heat Flux Sensors for Infrared Thermography in Convective Heat Transfer

    PubMed Central

    Carlomagno, Giovanni Maria; de Luca, Luigi; Cardone, Gennaro; Astarita, Tommaso

    2014-01-01

    This paper reviews the most dependable heat flux sensors, which can be used with InfraRed (IR) thermography to measure convective heat transfer coefficient distributions, and some of their applications performed by the authors' research group at the University of Naples Federico II. After recalling the basic principles that make IR thermography work, the various heat flux sensors to be used with it are presented and discussed, describing their capability to investigate complex thermo-fluid-dynamic flows. Several applications to streams, which range from natural convection to hypersonic flows, are also described. PMID:25386758

  9. Geothermal flux through palagonitized tephra, Surtsey, Iceland - The Surtsey temperature-data-relay experiment via Landsat-1

    NASA Technical Reports Server (NTRS)

    Friedman, J. D.; Preble, D. M.; Jakobsson, S.

    1976-01-01

    The net geothermal flux through palagonitized basaltic tephra rims of the Surtur I and Surtur II craters at Surtsey, Iceland, in 1972, is estimated at 780 plus or minus 325 microcal/sq cm/s, indicating a decline since 1969 when a flux of 1500 microcal/sq cm/s was estimated. Heat flux in this range characterizes the postvolcanic environment on Surtsey in which the subaerial polagonitization of basaltic tephra is associated with mass transfer of hydrothermal vapor, either of meteoric or sea-water origin, only a few years after cessation of eruptive activity. The flux estimation is the result of the Surtsey data-relay experiment via Landsat-1 which was carried out in several phases. Temperature data were transmitted for a 38-day period in November and December 1972. A near-surface vertical gradient of 69.4 C/m was obtained, suggesting a mixed mechanism of heat transfer, partitioned between conduction and convection.

  10. Using geothermal energy to heat a portion of a formation for an in situ heat treatment process

    DOEpatents

    Pieterson, Roelof; Boyles, Joseph Michael; Diebold, Peter Ulrich

    2010-06-08

    Methods of using geothermal energy to treat subsurface formations are described herein. Methods for using geothermal energy to treat a subsurface treatment area containing or proximate to hydrocarbons may include producing geothermally heated fluid from at least one subsurface region. Heat from at least a portion of the geothermally heated fluid may be transferred to the subsurface treatment area to heat the subsurface treatment area. At least some hydrocarbon fluids may be produced from the formation.

  11. Feasibility study of geothermal heating, Modoc Lassen housing project

    SciTech Connect

    Not Available

    1981-11-01

    This study evaluates the feasibility of using geothermal water for space and domestic water heating systems at the elderly housing project now ready for construction at the Modoc Lassen Indian Reservation. For the six units considered, the space heating load is four times the domestic water heating load. Since the geothermal water temperature is uncertain, two scenarios were evaluated. In the first, which assumes 160/sup 0/F supply temperature, the geothermal system is assumed to satisfy the entire space and domestic water heating loads. In the second, which assumes the supply temperature to be less than 120/sup 0/F at the wellhead only space heating is provided. The economics of the first scenario are quite favorable. The additional expenditure of $15,630 is projected to save $3522 annually at current energy costs, and the life cycle cost study projects a discounted rate of return on the investment of 44.4%. Surprisingly, the investment is even more favorable for the second scenario, due to the higher cost and lower resultant savings for the domestic water components. Forced air space heating from geothermal is recommended. Domestic water heating is recommended pending additional information on supply water temperature.

  12. Geothermal Well and Heat Flow Data for the United States (Southern Methodist University (SMU) Geothermal Laboratory)

    DOE Data Explorer

    Blackwell, D.D. and others

    Southern Methodist University makes two databases and several detailed maps available. The Regional Heat Flow Database for the United States contains information on primarily regional or background wells that determine the heat flow for the United States; temperature gradients and conductivity are used to generate heat flow measurements. Information on geology of the location, porosity, thermal conductivity, water table depth, etc. are also included when known. There are usually three data files for each state or region. The first files were generated in 1989 for the data base creating the Decade of North America Geology (DNAG) Geothermal Map. The second set is from 1996 when the data base was officially updated for the Department of Energy. The third set is from 1999 when the Western U.S. High Temperature Geothermal data base was completed. As new data is received, the files continue to be updated. The second major resource is the Western Geothermal Areas Database, a database of over 5000 wells in primarily high temperature geothermal areas from the Rockies to the Pacific Ocean. The majority of the data are from company documents, well logs, and publications with drilling dates ranging from 1960 to 2000. Many of the wells were not previously accessible to the public. Users will need to register, but will then have free, open access to the databases. The contents of each database can be viewed and downloaded as Excel spreadsheets. See also the heat flow maps at http://www.smu.edu/geothermal/heatflow/heatflow.htm

  13. Evidence for elevated and spatially variable geothermal flux beneath the West Antarctic Ice Sheet.

    PubMed

    Schroeder, Dustin M; Blankenship, Donald D; Young, Duncan A; Quartini, Enrica

    2014-06-24

    Heterogeneous hydrologic, lithologic, and geologic basal boundary conditions can exert strong control on the evolution, stability, and sea level contribution of marine ice sheets. Geothermal flux is one of the most dynamically critical ice sheet boundary conditions but is extremely difficult to constrain at the scale required to understand and predict the behavior of rapidly changing glaciers. This lack of observational constraint on geothermal flux is particularly problematic for the glacier catchments of the West Antarctic Ice Sheet within the low topography of the West Antarctic Rift System where geothermal fluxes are expected to be high, heterogeneous, and possibly transient. We use airborne radar sounding data with a subglacial water routing model to estimate the distribution of basal melting and geothermal flux beneath Thwaites Glacier, West Antarctica. We show that the Thwaites Glacier catchment has a minimum average geothermal flux of ∼ 114 ± 10 mW/m(2) with areas of high flux exceeding 200 mW/m(2) consistent with hypothesized rift-associated magmatic migration and volcanism. These areas of highest geothermal flux include the westernmost tributary of Thwaites Glacier adjacent to the subaerial Mount Takahe volcano and the upper reaches of the central tributary near the West Antarctic Ice Sheet Divide ice core drilling site.

  14. Evidence for elevated and spatially variable geothermal flux beneath the West Antarctic Ice Sheet

    PubMed Central

    Schroeder, Dustin M.; Blankenship, Donald D.; Young, Duncan A.; Quartini, Enrica

    2014-01-01

    Heterogeneous hydrologic, lithologic, and geologic basal boundary conditions can exert strong control on the evolution, stability, and sea level contribution of marine ice sheets. Geothermal flux is one of the most dynamically critical ice sheet boundary conditions but is extremely difficult to constrain at the scale required to understand and predict the behavior of rapidly changing glaciers. This lack of observational constraint on geothermal flux is particularly problematic for the glacier catchments of the West Antarctic Ice Sheet within the low topography of the West Antarctic Rift System where geothermal fluxes are expected to be high, heterogeneous, and possibly transient. We use airborne radar sounding data with a subglacial water routing model to estimate the distribution of basal melting and geothermal flux beneath Thwaites Glacier, West Antarctica. We show that the Thwaites Glacier catchment has a minimum average geothermal flux of ∼114 ± 10 mW/m2 with areas of high flux exceeding 200 mW/m2 consistent with hypothesized rift-associated magmatic migration and volcanism. These areas of highest geothermal flux include the westernmost tributary of Thwaites Glacier adjacent to the subaerial Mount Takahe volcano and the upper reaches of the central tributary near the West Antarctic Ice Sheet Divide ice core drilling site. PMID:24927578

  15. GEOTHERMAL / SOLAR HYBRID DESIGNS: USE OF GEOTHERMAL ENERGY FOR CSP FEEDWATER HEATING

    SciTech Connect

    Craig Turchi; Guangdong Zhu; Michael Wagner; Tom Williams; Dan Wendt

    2014-10-01

    This paper examines a hybrid geothermal / solar thermal plant design that uses geothermal energy to provide feedwater heating in a conventional steam-Rankine power cycle deployed by a concentrating solar power (CSP) plant. The geothermal energy represents slightly over 10% of the total thermal input to the hybrid plant. The geothermal energy allows power output from the hybrid plant to increase by about 8% relative to a stand-alone CSP plant with the same solar-thermal input. Geothermal energy is converted to electricity at an efficiency of 1.7 to 2.5 times greater than would occur in a stand-alone, binary-cycle geothermal plant using the same geothermal resource. While the design exhibits a clear advantage during hybrid plant operation, the annual advantage of the hybrid versus two stand-alone power plants depends on the total annual operating hours of the hybrid plant. The annual results in this draft paper are preliminary, and further results are expected prior to submission of a final paper.

  16. Heat Production as a Tool in Geothermal Exploration

    NASA Astrophysics Data System (ADS)

    Rhodes, J. M.; Koteas, C.; Mabee, S. B.; Thomas, M.; Gagnon, T.

    2012-12-01

    Heat flow data (together with knowledge, or assumptions, of stratigraphy, thermal conductivity and heat production) provide the prime parameter for estimating the potential of geothermal resources. Unfortunately this information is expensive to obtain as it requires deep boreholes. Consequently it is sparse or lacking in areas not traditionally considered as having geothermal potential. New England (and most of the northeastern U.S.A.) is one such area. However, in the absence of volcano-derived hydrothermal activity with its attendant high heat flow, granitic plutons provide an alternative geothermal resource. Compared with other crustal rocks, granites contain higher concentrations of heat-producing elements (K, U, Th). Additionally, they are relatively homogeneous, compared to surrounding country rock, allowing for stimulation through hydro-fracking of large (>1 km3) geothermal reservoirs. Consequently we have adopted a different approach, obtaining heat production data rather then relying on the very sparse heat flow data. Birch and colleagues long since recognized the relationship between heat flow and heat production as an integral part of their concept of Heat Flow Provinces. Heat production is readily determined in the laboratory by measuring the density of a sample and the concentrations of its heat-producing elements potassium, uranium and thorium. We have determined the heat production for 570 samples from most of the major granitic and gneissic bodies in Massachusetts and Connecticut. We have also measured these parameters for 70 sedimentary rocks that cover granites and gneiss in the Connecticut and Narragansett Basins. This data is being used to calculate inferred heat flow data for these localities. Comparison of these inferred heat flow values with the sparse number of those measured directly in boreholes in the two States is encouraging, indicating that this approach has merit. We have also measured thermal conductivity on all of these samples

  17. Vertical eddy heat fluxes from model simulations

    NASA Technical Reports Server (NTRS)

    Stone, Peter H.; Yao, Mao-Sung

    1991-01-01

    Vertical eddy fluxes of heat are calculated from simulations with a variety of climate models, ranging from three-dimensional GCMs to a one-dimensional radiative-convective model. The models' total eddy flux in the lower troposphere is found to agree well with Hantel's analysis from observations, but in the mid and upper troposphere the models' values are systematically 30 percent to 50 percent smaller than Hantel's. The models nevertheless give very good results for the global temperature profile, and the reason for the discrepancy is unclear. The model results show that the manner in which the vertical eddy flux is carried is very sensitive to the parameterization of moist convection. When a moist adiabatic adjustment scheme with a critical value for the relative humidity of 100 percent is used, the vertical transports by large-scale eddies and small-scale convection on a global basis are equal: but when a penetrative convection scheme is used, the large-scale flux on a global basis is only about one-fifth to one-fourth the small-scale flux. Comparison of the model results with observations indicates that the results with the latter scheme are more realistic. However, even in this case, in mid and high latitudes the large and small-scale vertical eddy fluxes of heat are comparable in magnitude above the planetary boundary layer.

  18. Market penetration analysis for direct heat geothermal energy applications

    SciTech Connect

    Thomas, R.J.; Nelson, R.A.

    1981-06-01

    This study is concerned with the estimation of the National geothermal market potential and penetration in direct heat applications for residences and certain industry segments. An important aspect of this study is that the analysis considers both known and anticipated goethermal resources. This allows for an estimation of the longer-range potential for geothermal applications. Thus the approach and results of this study provide new insights and valuable information not obtained from more limited, site-specific types of analyses. Estimates made in this study track geothermal market potential and projected penetration from the present to the year 2020. Private sector commercialization of geothermal energy over this period requires assistance in the identification of markets and market sizes, potential users, and appropriate technical applications.

  19. Municipal geothermal heat utilization plan for Glenwood Springs, Colorado

    NASA Astrophysics Data System (ADS)

    1980-12-01

    The results show that the use of geothermal heat is indeed feasible when compared to the cost of natural gas. The proposed system is composed of a wellhead plate heat exchanger which feeds a closed distribution loop of treated water circulated to the buildings which form the load. The base case system was designed to supply twice the demand created by the seven public buildings in order to take advantage of some economies of scale. To increase the utilization factor of the available geothermal energy, a peaking boiler which burns natural gas is recommended. Disposal of the cooled brine would be via underground injection.

  20. Geothermal direct-heat utilization assistance. Quarterly report, October--December 1996

    SciTech Connect

    1996-12-31

    This report summarizes geothermal technical assistance, R&D and technology transfer activities of the Geo-Heat Center at Oregon Institute of Technology for the first quarter of FY-97. It describes 174 contracts with parties during this period related to technical assistance with geothermal direct heat projects. Areas dealt with include geothermal heat pumps, space heating, greenhouses, aquaculture, equipment, economics and resources. Research activities are summarized on greenhouse peaking. Outreach activities include the publication of a geothermal direct use Bulletin, dissemination of information, geothermal library, technical papers and seminars, and progress monitor reports on geothermal resources and utilization.

  1. Economics of geothermal, solar, and conventional space heating

    SciTech Connect

    Fassbender, L.L.; Bloomster, C.H.; Price, B.A.

    1980-01-01

    The competitive outlook for geothermal and solar heating changed dramatically during the past year. With the recent sharp price increases in imported oil and natural gas and the planned decontrol of domestic prices, geothermal and solar energy will become competitive for space heating throughout most of the country. Under these new conditions, geothermal energy could competitively provide about 40% of the national demand for space heat and domestic hot water (about 7 quads based on 1980 demands). Nearly all of the geothermal energy demand would be in high-population-density areas. Solar energy could competitively provide about 50% (about 9 quads) of the annual demand. Most of the solar energy demand would be concentrated in suburban and rural areas. Conventional energy should remain competitive for about 30% (about 5 quads) of the annual demand. Conventional energy demand would be concentrated in the South and as supplemental energy for solar/conventional systems. Geothermal, solar, and conventional energy would be equally competitive for about 20% of the annual demand, which is why the individual market shares add to 120%.

  2. Measurement of local high-level, transient surface heat flux

    NASA Technical Reports Server (NTRS)

    Liebert, Curt H.

    1988-01-01

    This study is part of a continuing investigation to develop methods for measuring local transient surface heat flux. A method is presented for simultaneous measurements of dual heat fluxes at a surface location by considering the heat flux as a separate function of heat stored and heat conducted within a heat flux gage. Surface heat flux information is obtained from transient temperature measurements taken at points within the gage. Heat flux was determined over a range of 4 to 22 MW/sq m. It was concluded that the method is feasible. Possible applications are for heat flux measurements on the turbine blade surfaces of space shuttle main engine turbopumps and on the component surfaces of rocket and advanced gas turbine engines and for testing sensors in heat flux gage calibrators.

  3. Thermodynamic analysis of geothermal heat pump during the cold season

    NASA Astrophysics Data System (ADS)

    Dumitrașcu, G.; Dumencu, A.; Horbaniuc, B.; Atanasiu, M. V.

    2016-08-01

    The paper is analysing the performances (COP, power and, heating heat rate function of time) for a ground-coupled heat pump that is used to heat a space during winter, for a period of 180 days. The analysis purpose is to evaluate the time based changes in values of COP and, energy transfers of a geothermal heat pump, considering a scenario for the variation of the ambient temperature in time and an analytical solution for the time dependence of the soil one. The temperatures and the energy transfer rates were determined on the basis of the irreversible entropy balance equation.

  4. Measurement of geothermal flux through poorly consolidated sediments

    USGS Publications Warehouse

    Sass, J.H.; Munroe, R.J.; Lachenbruch, A.H.

    1968-01-01

    In many regions, crystalline rocks are covered by hundreds of meters of unconsolidated and poorly consolidated sediments. Estimates of heat flux within these sediments using standard continental techniques (temperature and conductivity measurements at intervals of 10 to 30 meters) are unreliable, mainly because of the difficulty in obtaining and preserving representative lengths of core. However, it is sometimes feasible to use what amounts to an oceanographic technique by making closely spaced temperature and conductivity measurements within short cored intervals. This is demonstrated in a borehole at Menlo Park, California (37??27???N, 122??10???W, elevation 16 meters), where heat flows determined over 12 separate 1-meter intervls al lie within 10% of their mean value; 2.2 ??cal/cm2 sec. ?? 1968.

  5. Geothermal Heat Pumps Score High Marks in Schools.

    ERIC Educational Resources Information Center

    National Renewable Energy Lab (DOE).

    Geothermal heat pumps (GHPs) are showing their value in providing lower operating and maintenance costs, energy efficiency, and superior classroom comfort. This document describes what GHPs are and the benefits a school can garner after installing a GHP system. Three case studies are provided that illustrate these benefits. Finally, the Department…

  6. Expanding Taylor bubble under constant heat flux

    NASA Astrophysics Data System (ADS)

    Voirand, Antoine; Benselama, Adel M.; Ayel, Vincent; Bertin, Yves

    2016-09-01

    Modelization of non-isothermal bubbles expanding in a capillary, as a contribution to the understanding of the physical phenomena taking place in Pulsating Heat Pipes (PHPs), is the scope of this paper. The liquid film problem is simplified and solved, while the thermal problem takes into account a constant heat flux density applied at the capillary tube wall, exchanging with the liquid film surrounding the bubble and also with the capillary tube outside medium. The liquid slug dynamics is solved using the Lucas-Washburn equation. Mass and energy balance on the vapor phase allow governing equations of bubble expansion to be written. The liquid and vapor phases are coupled only through the saturation temperature associated with the vapor pressure, assumed to be uniform throughout the bubble. Results show an over-heating of the vapor phase, although the particular thermal boundary condition used here always ensures an evaporative mass flux at the liquid-vapor interface. Global heat exchange is also investigated, showing a strong decreasing of the PHP performance to convey heat by phase change means for large meniscus velocities.

  7. Contactless heat flux control with photonic devices

    SciTech Connect

    Ben-Abdallah, Philippe; Biehs, Svend-Age

    2015-05-15

    The ability to control electric currents in solids using diodes and transistors is undoubtedly at the origin of the main developments in modern electronics which have revolutionized the daily life in the second half of 20th century. Surprisingly, until the year 2000 no thermal counterpart for such a control had been proposed. Since then, based on pioneering works on the control of phononic heat currents new devices were proposed which allow for the control of heat fluxes carried by photons rather than phonons or electrons. The goal of the present paper is to summarize the main advances achieved recently in the field of thermal energy control with photons.

  8. Reducing the Geothermal Exploration Risk by Carbon Dioxide Soil Flux Investigations

    NASA Astrophysics Data System (ADS)

    Carapezza, Maria Luisa; Barberi, Franco; Ranaldi, Massimo; Ricci, Tullio; Tarchini, Luca; De Simone, Gabriele; Gattuso, Alessandro; Silvestri, Mario

    2013-04-01

    In the exploration of medium to high enthalpy geothermal resources it happens rather frequently that deep wells find high temperatures but are not productive because they don't cross any permeable fractured reservoir. Because of the high cost of deep drillings, this aspect represents one of the main economic risks of geothermal exploration. A detailed survey of diffuse CO2 soil flux may allow to identify from the surface the permeable portions of a deep-seated actively degassing geothermal reservoir, drastically reducing this risk. In order to test the effectiveness of CO2 soil flux as a geothermal exploration tool we selected two volcanic areas north of Rome, Latera caldera and Marta zone near lake Bolsena, both hosting a geothermal reservoir with T>200 °C and where productive and non-productive wells had been drilled in the past. We proved that in both zones productive wells are located on high CO2 soil flux zones, whereas the not-productive wells are sited on low flux areas. In addition the surveys allowed to identify some as yet unexplored portions of the geothermal reservoirs where future wells should be conveniently located. Use of the same technique in the medium enthalpy geothermal system of Torre Alfina, Central Italy (T=140°C) showed that the presence of a thick impervious rock cover may be very effective in preventing gas leakages from the reservoir to the surface. Promising results have been obtained also by CO2 soil flux surveys in some geothermal areas of Honduras (Platanares, Azacualpa) and Costa Rica (Las Pailas). Obviously, CO2 flux cannot provide any estimate of temperature at depth, which has to be assessed with other geochemical or geophysical exploration techniques.

  9. Geothermal heating facilities for Frontier Inn, Susanville, California

    NASA Astrophysics Data System (ADS)

    1982-03-01

    A 38 unit motel composed of six major sections (coffee shop, A frame units, apartments, back units, two story units and office) was built over a number of years and exhibits widely varying types of construction. Space heating is provided by primarily electric resistance equipment with some propane use. Domestic hot water is provided primarily by propane with some electric resistance. The coffee shop uses fuel oil for both space and domestic hot water heating. A geothermal district heating system is being installed. Although the motel site is not located in the area of construction activity, it is expected that the pipeline will be extended. The potential of retrofitting the existing heating facilities at the inn to geothermal is studied.

  10. Heat pumps for geothermal applications: availability and performance. Final report

    SciTech Connect

    Reistad, G.M.; Means, P.

    1980-05-01

    A study of the performance and availability of water-source heat pumps was carried out. The primary purposes were to obtain the necessary basic information required for proper evaluation of the role of water-source heat pumps in geothermal energy utilization and/or to identify the research needed to provide this information. The Search of Relevant Literature considers the historical background, applications, achieved and projected performance evaluations and performance improvement techniques. The commercial water-source heat pump industry is considered in regard to both the present and projected availability and performance of units. Performance evaluations are made for units that use standard components but are redesigned for use in geothermal heating.

  11. Heat-flow mapping at the Geysers Geothermal Field

    SciTech Connect

    Thomas, R.P.

    1986-10-31

    Pertinent data were compiled for 187 temperature-gradient holes in the vicinity of The Geysers Geothermal field. Terrain-correction techniques were applied to most of the temperature-gradient data, and a temperature-gradient map was constructed. Cutting samples from 16, deep, production wells were analyzed for thermal conductivity. From these samples, the mean thermal conductivities were determined for serpentinized ultramafic rock, greenstone, and graywacke. Then, a heat flow map was made. The temperature-gradient and heat-flow maps show that The Geysers Geothermal field is part of a very large, northwesterly-trending, thermal anomaly; the commercially productive portion of the field may be 100 km/sup 2/ in area. The rate that heat energy flows through the surface by thermal conduction is estimated at 1.79 x 10/sup 9/MJ per year. The net heat energy loss from commercial production for 1983 is estimated at 180.14 x 10/sup 9/MJ.

  12. Geothermal direct-heat utilization assistance. Quarterly project progress report, January--March 1996

    SciTech Connect

    1996-05-01

    This report summarizes geothermal technical assistance, R&D, and technology transfer activities of the Geo-Heat Center. It describes 95 contacts with parties during this period related to technical assistance with goethermal direct heat projects. Areas dealt with include geothermal heat pumps, space heating, greenhouses, aquaculture, equipment, economics, and resources. Research activities are summarized on geothermal district heating system cost evaluation and silica waste utilization project. Outreach activities include publication of a geothermal direct use Bulletin, dissemination of information, goethermal library, technical papers and seminars, and progress monitor reports on geothermal resources and utilization.

  13. Municipal geothermal heat utilization plan for Glenwood Springs, Colorado

    SciTech Connect

    Not Available

    1980-12-31

    A study has been made of the engineering and economic feasibility of utilizing the geothermal resource underlying Glenwood Springs Colorado, to heat a group of public buildings. The results have shown that the use of geothermal heat is indeed feasible when compared to the cost of natural gas. The proposed system is composed of a wellhead plate heat exchanger which feeds a closed distribution loop of treated water circulated to the buildings which form the load. The base case system was designed to supply twice the demand created by the seven public buildings in order to take advantage of some economies of scale. To increase the utilization factor of the available geothermal energy, a peaking boiler which burns natural gas is recommended. Disposal of the cooled brine would be via underground injection. Considerable study was done to examine the impact of reduced operating temperature on the existing heating systems. Several options to minimize this problem were identified. Economic analyses were completed to determine the present values of heat from the geothermal system and from the present natural gas over a 30 year projected system life. For the base case savings of over $1 million were shown. Sensitivities of the economics to capital cost, operating cost, system size and other parameters were calculated. For all reasonable assumptions, the geothermal system was cheaper. Financing alternatives were also examined. An extensive survey of all existing data on the geology of the study has led to the prediction of resource parameters. The wellhead temperature of produced fluid is suspected to lie between 140 and 180/sup 0/F (60 and 82/sup 0/C). Flowrates may be as high as 1000 gpm (3800 liters per minute) from a reservoir formation that is 300 ft (90 m) thick beginning about 500 ft (150 m) below the suggested drill site in the proposed Two Rivers Park.

  14. Method of extracting heat from dry geothermal reservoirs

    DOEpatents

    Potter, R.M.; Robinson, E.S.; Smith, M.C.

    1974-01-22

    Hydraulic fracturing is used to interconnect two or more holes that penetrate a previously dry geothermal reservoir, and to produce within the reservoir a sufficiently large heat-transfer surface so that heat can be extracted from the reservoir at a usefully high rate by a fluid entering it through one hole and leaving it through another. Introduction of a fluid into the reservoir to remove heat from it and establishment of natural (unpumped) convective circulation through the reservoir to accomplish continuous heat removal are important and novel features of the method. (auth)

  15. Geothermal district heating system feasibility analysis, Thermopolis, Wyoming

    SciTech Connect

    Goering, S.W.; Garing, K.L.; Coury, G.; Mickley, M.C.

    1982-04-26

    The purpose of this study is to determine the technical and economic feasibility of constructing and operating a district heating system to serve the residential, commercial, and public sectors in Thermopolis. The project geothermal resource assessment, based on reviews of existing information and data, indicated that substantial hot water resources likely exist in the Rose Dome region 10 miles northeast of Thermopolis, and with quantities capable of supporting the proposed geothermal uses. Preliminary engineering designs were developed to serve the space heating and hot water heating demands for buildings in the Thermopolis-East Thermopolis town service area. The heating district design is based on indirect geothermal heat supply and includes production wells, transmission lines, heat exchanger units, and the closed loop distribution and collection system necessary to serve the individual customers. Three options are presented for disposal of the cooled waters-reinjection, river disposal, and agricultural reuse. The preliminary engineering effort indicates the proposed system is technically feasible. The design is sized to serve 1545 residences, 190 businesses, and 24 public buildings. The peak design meets a demand of 128.2 million Btu at production rates of 6400 gpm.

  16. Community Geothermal Technology Program: Bottom heating system using geothermal power for propagation. Final report, Phases 1 and 2

    SciTech Connect

    Downing, J.C.

    1990-01-01

    The objective is to develop and study a bottom-heating system in a greenhouse utilizing geothermal energy to aid germination and speed growth of palms. Source of heat was geothermal brine from HGP-A well. The project was successful; the heat made a dramatic difference with certain varieties, such as Areca catechu (betelnut) with 82% germination with heat, zero without. For other varieties, germination rates were much closer. Quality of seed is important. Tabs, figs.

  17. Geothermal Heat Pumps - Using the Earth to Heat and Cool Buildings

    SciTech Connect

    1999-09-01

    A heat pump--like an air conditioner or refrigerator--moves heat from one place to another. In the summer, a geothermal heat pump (GHP) operating in a cooling mode lowers indoor temperatures by transferring heat from inside a building to the ground outside or below it. Unlike an air conditioner, though, a heat pump's process can be reversed. In the winter, a GHP extracts

  18. Heat flux in a granular gas

    NASA Astrophysics Data System (ADS)

    Brey, J. J.; Ruiz-Montero, M. J.

    2012-11-01

    A peculiarity of the hydrodynamic Navier-Stokes equations for a granular gas is the modification of the Fourier law, with the presence of an additional contribution to the heat flux that is proportional to the density gradient. Consequently, the constitutive relation involves, in the case of a one-component granular gas, two transport coefficients: the usual (thermal) heat conductivity and a diffusive heat conductivity. A very simple physical interpretation of this effect, in terms of the mean free path and the mean free time is provided. It leads to the modified Fourier law with an expression for the diffusive Fourier coefficient that differs in a factor of the order of unity from the expression obtained by means of the inelastic Boltzmann equation. Also, some aspects of the Chapman-Enskog computation of the new transport coefficients as well as of the comparison between simulation results and theory are discussed.

  19. Direct heat geothermal opportunities at Pahoa, Hawaii

    SciTech Connect

    Moreau, J.; Jones, W.L.

    1980-09-01

    A geothermal commercial park located near Pahoa, Hawaii, has been found to be technically feasible. However, community acceptance varies from optimistic support for the job opportunities to only lukewarm acceptance by most residents of the nearby planned residential community. Interviews, team evaluations, and calculations of energy and transportation savings were used to reduce a list of candidate processes to four. These four include an ethanol plant, a cattle feed mill, a protein recovery plant, and a papaya processing facility. In addition, a research laboratory is planned for the evaluation of other processes identified as very promising.

  20. Development of heat flux sensors in turbine airfoils

    NASA Technical Reports Server (NTRS)

    Atkinson, W. H.; Strange, R. R.

    1984-01-01

    The objective is to develop heat flux sensors suitable for use on turbine airfoils and to verify the operation of the heat flux measurement techniques through laboratory experiments. The requirements for a program to investigate the measurement of heat flux on airfoils in areas of strong non-one-dimensional flow were also identified.

  1. Exergy analysis of the performance of low-temperature district heating system with geothermal heat pump

    NASA Astrophysics Data System (ADS)

    Sekret, Robert; Nitkiewicz, Anna

    2014-03-01

    Exergy analysis of low temperature geothermal heat plant with compressor and absorption heat pump was carried out. In these two concepts heat pumps are using geothermal water at 19.5 oC with spontaneous outflow 24 m3/h as a heat source. The research compares exergy efficiency and exergy destruction of considered systems and its components as well. For the purpose of analysis, the heating system was divided into five components: geothermal heat exchanger, heat pump, heat distribution, heat exchanger and electricity production and transportation. For considered systems the primary exergy consumption from renewable and non-renewable sources was estimated. The analysis was carried out for heat network temperature at 50/40 oC, and the quality regulation was assumed. The results of exergy analysis of the system with electrical and absorption heat pump show that exergy destruction during the whole heating season is lower for the system with electrical heat pump. The exergy efficiencies of total system are 12.8% and 11.2% for the system with electrical heat pump and absorption heat pump, respectively.

  2. Role of surface heat fluxes underneath cold pools

    NASA Astrophysics Data System (ADS)

    Gentine, Pierre; Garelli, Alix; Park, Seung-Bu; Nie, Ji; Torri, Giuseppe; Kuang, Zhiming

    2016-01-01

    The role of surface heat fluxes underneath cold pools is investigated using cloud-resolving simulations with either interactive or horizontally homogenous surface heat fluxes over an ocean and a simplified land surface. Over the ocean, there are limited changes in the distribution of the cold pool temperature, humidity, and gust front velocity, yet interactive heat fluxes induce more cold pools, which are smaller, and convection is then less organized. Correspondingly, the updraft mass flux and lateral entrainment are modified. Over the land surface, the heat fluxes underneath cold pools drastically impact the cold pool characteristics with more numerous and smaller pools, which are warmer and more humid and accompanied by smaller gust front velocities. The interactive fluxes also modify the updraft mass flux and reduce convective organization. These results emphasize the importance of interactive surface fluxes instead of prescribed flux boundary conditions, as well as the formulation of surface heat fluxes, when studying convection.

  3. Role of surface heat fluxes underneath cold pools

    PubMed Central

    Garelli, Alix; Park, Seung‐Bu; Nie, Ji; Torri, Giuseppe; Kuang, Zhiming

    2016-01-01

    Abstract The role of surface heat fluxes underneath cold pools is investigated using cloud‐resolving simulations with either interactive or horizontally homogenous surface heat fluxes over an ocean and a simplified land surface. Over the ocean, there are limited changes in the distribution of the cold pool temperature, humidity, and gust front velocity, yet interactive heat fluxes induce more cold pools, which are smaller, and convection is then less organized. Correspondingly, the updraft mass flux and lateral entrainment are modified. Over the land surface, the heat fluxes underneath cold pools drastically impact the cold pool characteristics with more numerous and smaller pools, which are warmer and more humid and accompanied by smaller gust front velocities. The interactive fluxes also modify the updraft mass flux and reduce convective organization. These results emphasize the importance of interactive surface fluxes instead of prescribed flux boundary conditions, as well as the formulation of surface heat fluxes, when studying convection. PMID:27134320

  4. Thermally conductive cementitious grout for geothermal heat pump systems

    DOEpatents

    Allan, Marita

    2001-01-01

    A thermally conductive cement-sand grout for use with a geothermal heat pump system. The cement sand grout contains cement, silica sand, a superplasticizer, water and optionally bentonite. The present invention also includes a method of filling boreholes used for geothermal heat pump systems with the thermally conductive cement-sand grout. The cement-sand grout has improved thermal conductivity over neat cement and bentonite grouts, which allows shallower bore holes to be used to provide an equivalent heat transfer capacity. In addition, the cement-sand grouts of the present invention also provide improved bond strengths and decreased permeabilities. The cement-sand grouts can also contain blast furnace slag, fly ash, a thermoplastic air entraining agent, latex, a shrinkage reducing admixture, calcium oxide and combinations thereof.

  5. Geothermal direct-heat study: Imperial County, California

    SciTech Connect

    Not Available

    1983-05-01

    Potential applications of geothermal energy which would be compatible with the agricultural activities in the county were identified and a plan to attract potential users to the area was developed. The intent of the first effort was to identify general classifications of industries which could utilize geothermal heat in production processes. Two levels of analyses were utilized for this effort. Initially, activities relying on previously developed engineering and industrial concepts were investigated to determine capital costs, employment, and potential energy savings. Second, innovative concepts not yet fully developed were investigated to determine their potential applicability to the agricultural base of the county. These investigations indicated that the major potential applications of geothermal heat would involve industries related to food processing or other direct agriculture-related uses of raw materials produced or imported to the county. An implementation plan which can be utilized by the county to market direct heat applications was developed. A socioeconomics analysis examined the potential effects on the county from development of direct heat projects. The county's planning and permitting requirements for dirct heat projects were also examined.

  6. Heat flow, radioactivity, gravity, and geothermal resources in northern Colorado and southern Wyoming

    SciTech Connect

    Decker, E.R.; Buelow, K.L.

    1981-12-01

    The surface heat flow values in the Sierra Madre-Medicine Bow-Laramie Mountains region are in the range 0.6 to 1.5 HFU. When the heat from local bedrock radioactivity is considered, the reduced flux in these mountains is low to normal (0.6 to 1.2 HFU). These data and the low to normal gradients (10 to 25/sup 0/C/km) in the studied drill holes strongly suggest that the resource potential of the Southern Rockies in Wyoming is low. The geothermal resource potential of the sedimentary basins in Wyoming that border these mountains also appears to be low because preliminary estimates for the flux in these areas are less than or equal to 1.5 HFU and the average gradients in analyzed drill holes are generally less than or equal to 30/sup 0/C/km. In contrast to southern Wyoming, the high surface and reduced heat flows strongly suggest that the Park areas and other parts of the Southern Rockies in northern Colorado are potentially valuable geothermal resource areas. The narrow northerly borders (less than or equal to 50 km) of these positive anomalies suggest that some of the resources could be shallow, as does the evidence for regional igneous and tectonic activity in the late Cenozoic. The small number of combined heat flow and radioactivity stations precludes detailed site-specific evaluations in these regions, but a few generalizations are made.

  7. Geothermal direct-heat utilization assistance. Quarterly progress report, April--June 1993

    SciTech Connect

    Not Available

    1993-08-01

    Progress is reported on the following R&D activities: evaluation of lineshaft turbine pump problems, geothermal district heating marketing strategy, and greenhouse peaking analysis. Other activities are reported on technical assistance, technology transfer, and the geothermal progress monitor.

  8. Geothermal direct-heat utilization assistance. Federal Assistance Program, Quarterly project progress report, October--December 1994

    SciTech Connect

    Not Available

    1994-12-31

    The report summarizes activities of the Geo-Heat Center (GHC) at Oregon Institute of Technology for the first quarter of Fiscal Year 1995. It describes contacts with parties during this period related to assistance with geothermal direct heat projects. Areas dealt with include geothermal heat pumps, space heating, greenhouses, aquaculture, resources and equipment. Research is also being conducted on geothermal energy cost evaluation, low-temperature geothermal resource assessment, use of silica waste from the Cerro Prieto geothermal field as construction materials and geothermal heat pumps. Outreach activities include the publication of a quarterly Bulletin on direct heat applications and dissemination of information on low-temperature geothermal resources and utilization.

  9. Plug-type heat flux gauge

    NASA Technical Reports Server (NTRS)

    Liebert, Curt H. (Inventor); Koch, John, Jr. (Inventor)

    1991-01-01

    A plug-type heat flux gauge formed in a material specimen and having a thermoplug integrally formed in the material specimen, and a method for making the same are disclosed. The thermoplug is surrounded by a concentric annulus, through which thermocouple wires are routed. The end of each thermocouple wire is welded to the thermoplug, with each thermocouple wire welded at a different location along the length of the thermoplug. The thermoplug and concentric annulus may be formed in the material specimen by electrical discharge machining and trepanning procedures.

  10. Geothermal direct-heat utilization assistance. Quarterly project progress report, July 1994--September 1994

    SciTech Connect

    Not Available

    1994-10-01

    This paper is a third quarter 1994 report of activities of the Geo-Heat Center of Oregon Institute of Technology. It describes contacts with parties during this period related to assistance with geothermal direct heat applications. Areas dealt with include geothermal heat pumps, space heating, greenhouses, aquaculture, resources, and equipment. Research is also being conducted on failures of vertical lineshaft turbines in geothermal wells.

  11. Recovery Act: Cedarville School District Retrofit of Heating and Cooling Systems with Geothermal Heat Pumps and Ground Source Water Loops

    SciTech Connect

    Jarrell, Mark

    2013-09-30

    Cedarville School District retrofitted the heating and cooling systems in three campus areas (High School, Middle School, and Upper Elementary School) with geothermal heat pumps and ground source water loops, as a demonstration project for the effective implementation of geothermal heat pump systems and other energy efficiency and air quality improvements.

  12. Heat flow and geothermal potential of Kansas

    SciTech Connect

    Blackwell, D.D.; Steele, J.L.

    1981-01-01

    The plan of the US Geological Survey and Kansas Geological Survey to drill four deep hydrologic tests in Kansas prompted a geothermal study in these wells. These wells were drilled through the Arbuckle Group to within a few feet of basement and two of the holes were deepened on into the basement and core samples collected of the basement rock. Because of the depth of the four holes and because of the fact that they have been cased through most of their depth and left undisturbed to reach temperature equilibrium, it is possible to get highly accurate, stable temperature measurements through the complete sedimentary section. In addition an extensive suite of geophysical logs were obtained for each of the holes (gamma-ray, travel time, density, neutron porosity, electric, etc.) and cuttings were collected at frequent intervals. In addition 5 other holes were logged as part of this study. For these holes cutting samples and geophysical logs are not available, but the additional holes offer useful supplementary information on the temperature regime in other parts of Kansas.

  13. Other geothermal space-heating system in Elko, Nevada

    SciTech Connect

    Bugenig, D.C.; Scolari, D.; Vietti, J.

    1987-08-01

    In February 1985, the Elko County School District completed a 1971-ft deep geothermal well at the site of the Elko Junior High School, Elko, Nevada. Aquifer stress test results indicated that the well could sustain artesian flows of as much as 325 gal/min of 190/sup 0/F water. Because the productivity of the well, up to 15 x 10/sup 6/ Btu/hr, far exceeded the heating demand of the junior high school, a district space heating scheme was conceived to heat additional school-district facilities, a hospital, convention center, municipal swimming pool, and city offices. Estimated savings to the public entities involved and, ultimately, the taxpayers in Elko were projected at $285,000 annually. Approximately one mile of distribution lines were laid and 13 buildings were retrofitted to geothermal heating in time for the 1986-1987 heating season. The system is the second for Elko, the first being the Elko Heat Company that serves commercial users in the downtown area.

  14. Estimation of the surface heat fluxes over Taiwan's Chiayi Plain

    NASA Astrophysics Data System (ADS)

    Chang, T.; Liou, Y.

    2008-12-01

    Traditionally, surface energy fluxes are obtained by model simulations or empirical equations with auxiliary meteorological data. These methods may not effectively represent the surface heat fluxes in a regional scale due to scene variability. On the other hand, remote sensing has the advantage to acquire data of a large area in an instantaneous view. They can be further used to retrieve surface radiation and heat fluxes over a large area. In this study, the airborne and satellite images in conjunction with meteorological data and ground observations were used to estimate the surface heat fluxes over Taiwan's Chiayi Plain. The results indicate that surface heat fluxes can be properly determined from both airborne and satellite images. The correlation coefficient of surface heat fluxes with in situ corresponding observations is over 0.60. We also observe that the remote sensing data can efficiently provide a long term monitoring of surface heat fluxes over Taiwan's Chiayi Plain.

  15. Elevated carbon dioxide flux at the Dixie Valley geothermal field, Nevada; relations between surface phenomena and the geothermal reservoir

    USGS Publications Warehouse

    Bergfeld, D.; Goff, F.; Janik, C.J.

    2001-01-01

    In the later part of the 1990s, a large die-off of desert shrubs occurred over an approximately 1 km2 area in the northwestern section of the Dixie Valley (DV) geothermal field. This paper reports results from accumulation-chamber measurements of soil CO2 flux from locations in the dead zone and stable isotope and chemical data on fluids from fumaroles, shallow wells, and geothermal production wells within and adjacent to the dead zone. A cumulative probability plot shows three types of flux sites within the dead zone: Locations with a normal background CO2 flux (7 g m-2 day-1); moderate flux sites displaying "excess" geothermal flux; and high flux sites near young vents and fumaroles. A maximum CO2 flux of 570 g m-2 day-1 was measured at a location adjacent to a fumarole. Using statistical methods appropriate for lognormally distributed populations of data, estimates of the geothermal flux range from 7.5 t day-1 from a 0.14-km2 site near the Stillwater Fault to 0.1 t day-1 from a 0.01 -km2 location of steaming ground on the valley floor. Anomalous CO2 flux is positively correlated with shallow temperature anomalies. The anomalous flux associated with the entire dead zone area declined about 35% over a 6-month period. The decline was most notable at a hot zone located on an alluvial fan and in the SG located on the valley floor. Gas geochemistry indicates that older established fumaroles along the Stillwater Fault and a 2-year-old vent in the lower section of the dead zone discharge a mixture of geothermal gases and air or gases from air-saturated meteoric water (ASMW). Stable isotope data indicate that steam from the smaller fumaroles is produced by ??? 100??C boiling of these mixed fluids and reservoir fluid. Steam from the Senator fumarole (SF) and from shallow wells penetrating the dead zone are probably derived by 140??C to 160??C boiling of reservoir fluid. Carbon-13 isotope data suggest that the reservoir CO2 is produced mainly by thermal decarbonation of

  16. Long-term predictions of minewater geothermal systems heat resources

    NASA Astrophysics Data System (ADS)

    Harcout-Menou, Virginie; de ridder, fjo; laenen, ben; ferket, helga

    2014-05-01

    Abandoned underground mines usually flood due to the natural rise of the water table. In most cases the process is relatively slow giving the mine water time to equilibrate thermally with the the surrounding rock massif. Typical mine water temperature is too low to be used for direct heating, but is well suited to be combined with heat pumps. For example, heat extracted from the mine can be used during winter for space heating, while the process could be reversed during summer to provide space cooling. Altough not yet widely spread, the use of low temperature geothermal energy from abandoned mines has already been implemented in the Netherlands, Spain, USA, Germany and the UK. Reliable reservoir modelling is crucial to predict how geothermal minewater systems will react to predefined exploitation schemes and to define the energy potential and development strategy of a large-scale geothermal - cold/heat storage mine water systems. However, most numerical reservoir modelling software are developed for typical environments, such as porous media (a.o. many codes developed for petroleum reservoirs or groundwater formations) and cannot be applied to mine systems. Indeed, mines are atypical environments that encompass different types of flow, namely porous media flow, fracture flow and open pipe flow usually described with different modelling codes. Ideally, 3D models accounting for the subsurface geometry, geology, hydrogeology, thermal aspects and flooding history of the mine as well as long-term effects of heat extraction should be used. A new modelling approach is proposed here to predict the long-term behaviour of Minewater geothermal systems in a reactive and reliable manner. The simulation method integrates concepts for heat and mass transport through various media (e.g., back-filled areas, fractured rock, fault zones). As a base, the standard software EPANET2 (Rossman 1999; 2000) was used. Additional equations for describing heat flow through the mine (both

  17. Geothermal energy: clean power from the Earth's heat

    USGS Publications Warehouse

    Duffield, Wendell A.; Sass, John H.

    2003-01-01

    Societies in the 21st century require enormous amounts of energy to drive the machines of commerce and to sustain the lifestyles that many people have come to expect. Today, most of this energy is derived from oil, natural gas, and coal, supplemented by nuclear power. Local exceptions exist, but oil is by far the most common source of energy worldwide. Oil resources, however, are nonrenewable and concentrated in only a few places around the globe, creating uncertainty in long-term supply for many nations. At the time of the Middle East oil embargo of the 1970s, about a third of the United States oil supply was imported, mostly from that region. An interruption in the flow of this import disrupted nearly every citizen’s daily life, as well as the Nation’s economy. In response, the Federal Government launched substantial programs to accelerate development of means to increasingly harness “alternative energies”—primarily biomass, geothermal, solar, and wind. The new emphasis on simultaneously pursuing development of several sources of energy recognized the timeless wisdom found in the proverb of “not putting all eggs in one basket.” This book helps explain the role that geothermal resources can play in helping promote such diversity and in satisfying our Nation’s vast energy needs as we enter a new millennium. For centuries, people have enjoyed the benefits of geothermal energy available at hot springs, but it is only through technological advances made during the 20th century that we can tap this energy source in the subsurface and use it in a variety of ways, including the generation of electricity. Geothermal resources are simply exploitable concentrations of the Earth’s natural heat (thermal energy). The Earth is a bountiful source of thermal energy, continuously producing heat at depth, primarily by the decay of naturally occurring radioactive isotopes—principally of uranium, thorium, and potassium—that occur in small amounts in all rocks

  18. Thin Film Heat Flux Sensors: Design and Methodology

    NASA Technical Reports Server (NTRS)

    Fralick, Gustave C.; Wrbanek, John D.

    2013-01-01

    Thin Film Heat Flux Sensors: Design and Methodology: (1) Heat flux is one of a number of parameters, together with pressure, temperature, flow, etc. of interest to engine designers and fluid dynamists, (2) The measurement of heat flux is of interest in directly determining the cooling requirements of hot section blades and vanes, and (3)In addition, if the surface and gas temperatures are known, the measurement of heat flux provides a value for the convective heat transfer coefficient that can be compared with the value provided by CFD codes.

  19. Underground Mine Water Heating and Cooling Using Geothermal Heat Pump Systems

    SciTech Connect

    Watzlaf, G.R.; Ackman, T.E.

    2006-03-01

    In many regions of the world, flooded mines are a potentially cost-effective option for heating and cooling using geothermal heat pump systems. For example, a single coal seam in Pennsylvania, West Virginia, and Ohio contains 5.1 x 1012 L of water. The growing volume of water discharging from this one coal seam totals 380,000 L/min, which could theoretically heat and cool 20,000 homes. Using the water stored in the mines would conservatively extend this option to an order of magnitude more sites. Based on current energy prices, geothermal heat pump systems using mine water could reduce annual costs for heating by 67% and cooling by 50% over conventional methods (natural gas or heating oil and standard air conditioning).

  20. Economic assessment of geothermal direct heat technology: A review of five DOE demonstration projects

    SciTech Connect

    Hederman, William F. Jr.; Cohen, Laura A.

    1981-06-01

    In this report the cost of using low temperature geothermal energy resources for direct heating applications is compared to the costs associated with conventional heating fuels. The projects compared all involved replacing conventional fuels (e.g., natural gas and fuel oils) with geothermal energy in existing heating systems. The cost of using geothermal energy in existing systems was also compared with the cost of new coal-fired equipment.

  1. Method for limiting heat flux in double-wall tubes

    DOEpatents

    Hwang, Jaw-Yeu

    1982-01-01

    A method of limiting the heat flux in a portion of double-wall tubes including heat treating the tubes so that the walls separate when subjected to high heat flux and supplying an inert gas mixture to the gap at the interface of the double-wall tubes.

  2. Bidirectional solar wind electron heat flux events

    NASA Technical Reports Server (NTRS)

    Gosling, J. T.; Baker, D. N.; Bame, S. J.; Feldman, W. C.; Zwickl, R. D.; Smith, E. J.

    1987-01-01

    ISEE 3 plasma and magnetic field data are used here to document the general characteristics of bidirectional electron heat flux events (BEHFEs). Significant field rotations often occur at the beginning and/or end of such events and, at times, the large-field rotations characteristic of 'magnetic clouds' are present. Approximately half of all BEHFEs are associated with and follow interplanetary shocks, while the other events have no obvious shock associations. When shock-associated, the delay from shock passage typically is about 13 hours, corresponding to a radial separation of about 0.16 AU. When independent of any shock association, BEHFEs typically are about 0.13 AU thick in the radial direction. It is suggested that BEHFEs are one of the more prominent signatures of coronal mass ejection events in the solar wind at 1 AU.

  3. Natural analogs for enhanced heat recovery from geothermal systems

    SciTech Connect

    Nielson, Dennis L.

    1996-01-24

    High-temperature hydrothermal systems are physically and chemically zoned with depth. The energy input is from a magmatic zone, intruded by igneous bodies, that may also contribute variable amounts of magmatic fluid to the system. The heat source is directly overlain by a section of rocks, that due to their elevated temperature, respond to stress in a ductile fashion. The ductile zone is, in turn, overlain by a section of rocks that respond to stress in a brittle fashion, where water is able to circulate through fractures (the geothermal reservoir) and will be termed the hydrothermal circulation zone. Ancient and modern high-temperature geothermal systems show a predictable sequence of evolutionary events affecting these stratified zones. Metamorphic core complexes are uplifts, formed in highly extended terrains, that expose fossil brittle-ductile transition zones. Formerly ductile rocks have had brittle fractures superimposed on them, and meteoric hydrothermal systems are associated with the brittle fracturing. Porphyry copper deposits typically evolve from magmatic to meteoric hydrothermal systems. At the Larderello geothermal system, the brittle- ductile transition has been mapped using reflection seismology, and the zone has been penetrated by the San Pompeo 2 well where temperatures >420°C were encountered. Although neo-granitic dikes have been penetrated by drilling in the Larderello area, the brittle- ductile transition is largely above the inferred plutonic heat source. In the Geysers system, in contrast, the present steam system has been superimposed on young plutonic rocks and the inferred brittle-ductile transition is present at a depth of about 4.7 km within the plutonic rocks. As hydrothermal reservoirs are depleted, or surface facilities are restricted by environmental considerations, interest will turn to the deeper portions of known systems. Japan already has an aggressive program to develop Deep-seated and Magma-Ambient resources. This program, as

  4. Critical heat flux experiments in an internally heated annulus with a non-uniform, alternate high and low axial heat flux distribution (AWBA Development Program)

    SciTech Connect

    Beus, S.G.; Seebold, O.P.

    1981-02-01

    Critical heat flux experiments were performed with an alternate high and low heat flux profile in an internally heated annulus. The heated length was 84 inches (213 cm) with a chopped wave heat flux profile over the last 24 inches (61 cm) having a maximum-to-average heat flux ratio of 1.26. Three test sections were employed: one with an axially uniform heat flux profile as a base case and two with 60 inch (152 cm) uniform and 24 inch (61 cm) alternating high and low heat flux sections. The third test section had a 2.15 inch (5.46 cm) section with a peak-to-average heat flux ratio of 2.19 (hot patch) superimposed at the exit end of the alternating high and low heat flux profile.

  5. Heat flux measurement in SSME turbine blade tester

    NASA Astrophysics Data System (ADS)

    Liebert, Curt H.

    Surface heat flux values were measured in the turbine blade thermal cycling tester located at NASA-Marshall. This is the first time heat flux has been measured in a space shuttle main engine turbopump environment. Plots of transient and quasi-steady state heat flux data over a range of about 0 to 15 MW/sq m are presented. Data were obtained with a miniature heat flux gage device developed at NASA-Lewis. The results from these tests are being incorporated into turbine design models. Also, these gages are being considered for airfoil surface heat flux measurement on turbine vanes mounted in SSME turbopump test bed engine nozzles at Marshall. Heat flux effects that might be observed on degraded vanes are discussed.

  6. Heat flux measurement in SSME turbine blade tester

    NASA Astrophysics Data System (ADS)

    Liebert, Curt H.

    1990-11-01

    Surface heat flux values were measured in the turbine blade thermal cycling tester located at NASA-Marshall. This is the first time heat flux has been measured in a space shuttle main engine turbopump environment. Plots of transient and quasi-steady state heat flux data over a range of about 0 to 15 MW/sq m are presented. Data were obtained with a miniature heat flux gage device developed at NASA-Lewis. The results from these tests are being incorporated into turbine design models. Also, these gages are being considered for airfoil surface heat flux measurement on turbine vanes mounted in SSME turbopump test bed engine nozzles at Marshall. Heat flux effects that might be observed on degraded vanes are discussed.

  7. Electron heat flux constraints in the solar wind

    SciTech Connect

    Gary, S.P.; Skoug, R.M.; Daughton, W.

    1999-06-01

    Enhanced fluctuations from electromagnetic heat flux instabilities may, through wave-particle scattering, constrain the electron heat flux which flows parallel to the background magnetic field in the solar wind. A corollary of this hypothesis is that instability thresholds should correspond to observable bounds on the heat flux. Here plasma and magnetic field data from February and March 1995 of the Ulysses mission is analyzed in terms of the core/halo electron model to yield scaling relations of dimensionless electron parameters and empirical upper bounds on the dimensionless heat flux as functions of the core {beta}. Use of these scaling relations in linear Vlasov theory for the whistler and Alfv{acute e}n heat flux instabilities in homogeneous plasmas yields threshold conditions on the dimensionless heat flux which are also functions of the electron core {beta}. The empirical bounds and the theoretical thresholds are similar and are therefore consistent with the hypothesis. {copyright} {ital 1999 American Institute of Physics.}

  8. Heat flux measurement in SSME turbine blade tester

    NASA Technical Reports Server (NTRS)

    Liebert, Curt H.

    1990-01-01

    Surface heat flux values were measured in the turbine blade thermal cycling tester located at NASA-Marshall. This is the first time heat flux has been measured in a space shuttle main engine turbopump environment. Plots of transient and quasi-steady state heat flux data over a range of about 0 to 15 MW/sq m are presented. Data were obtained with a miniature heat flux gage device developed at NASA-Lewis. The results from these tests are being incorporated into turbine design models. Also, these gages are being considered for airfoil surface heat flux measurement on turbine vanes mounted in SSME turbopump test bed engine nozzles at Marshall. Heat flux effects that might be observed on degraded vanes are discussed.

  9. High heat flux engineering in solar energy applications

    SciTech Connect

    Cameron, C.P.

    1993-07-01

    Solar thermal energy systems can produce heat fluxes in excess of 10,000 kW/m{sup 2}. This paper provides an introduction to the solar concentrators that produce high heat flux, the receivers that convert the flux into usable thermal energy, and the instrumentation systems used to measure flux in the solar environment. References are incorporated to direct the reader to detailed technical information.

  10. Geothermal direct-heat utilization assistance. Quarterly project progress report, July--September 1997

    SciTech Connect

    1997-10-01

    This report summarizes geothermal technical assistance, R and D and technology transfer activities of the Geo-Heat Center at Oregon Institute of Technology for the fourth quarter of FY-97 (July--September 1997). It describes 213 contacts with parties during this period related to technical assistance with geothermal direct heat projects. Areas dealt with include requests for general information including maps, geothermal heat pumps, resource and well data, space heating and cooling, greenhouses, acquaculture, equipment, district heating, resorts and spas, and industrial applications. Research activities include the completion of a Comprehensive Greenhouse Developer Package. Work accomplished on the revision of the Geothermal Direct Use Engineering and Design Guidebook are discussed. Outreach activities include the publication of the Quarterly Bulletin (Vol. 18, No. 3), dissemination of information mainly through mailings of publications, geothermal library acquisition and use, participation in workshops, short courses, and technical meetings by the staff, and progress monitor reports on geothermal activities.

  11. Geothermal direct-heat utilization assistance. Quarterly report, January - March 1997

    SciTech Connect

    Lienau, P.

    1997-04-01

    This report summarizes geothermal technical assistance, R&D and technology transfer activities of the Geo-Heat Center at Oregon Institute of Technology for the second quarter of FY-97. It describes 176 contacts with parties during this period related to technical assistance with geothermal direct heat projects. Areas dealt with include geothermal heat pumps, space heating, greenhouses, aquaculture, equipment, economics and resources. Research activities are summarized on well pumping in commercial groundwater heat pump systems. A memorandum of understanding between the GHC and EIA is described. Work accomplishments on the Guidebook are discussed. Outreach activities include the publication of a geothermal direct use Bulletin, dissemination of information, geothermal library, technical papers and seminars, and progress monitor reports on geothermal resources and utilization.

  12. Geothermal direct-heat utilization assistance. Quarterly project progress report, April--June 1993

    SciTech Connect

    Lienau, P.

    1993-06-01

    Technical assistance was provided to 60 requests from 19 states. R&D progress is reported on: evaluation of lineshaft turbine pump problems, geothermal district heating marketing strategy, and greenhouse peaking analysis. Two presentations and one tour were conducted, and three technical papers were prepared. The Geothermal Progress Monitor reported: USGS Forum on Mineral Resources, Renewable Energy Tax Credits Not Working as Congress Intended, Geothermal Industry Tells House Panel, Newberry Pilot Project, and Low-Temperature Geothermal Resources in Nevada.

  13. Flux Tube Oscillations and Coronal Heating

    NASA Astrophysics Data System (ADS)

    Sobouti, Y.; Karami, K.; Nasiri, S.

    2003-05-01

    Wave transmission in low beta magnetic flux tubes has, mathematically, the same structure as the propagation of electromagnetic waves in optical fibers. In both cases the problem is reducible to a single wave equation for the longitudinal component of the perturbed field along the fiber/tube axis. We derive this equation, solve the dispersion relation associated with it, and assign three wave numbers to each mode. In cylindrical coordinates (r, phi, z), for a given phi-wave number, the plane of the r- and z- wave numbers is divided into one ``mode zone" in which each grid point is a possible mode of the system and one ``forbidden zone" in which no mode may dwell. The cutoff line, the boundary of the two zones, is given both analytically and numerically. Next we introduce weak resistive and viscous dissipation to the system, solve for the decay time of each mode and for the densities of heat generation rates by each dissipative process. The two densities have identical spatial dependencies, but different magnitudes. The resistive heat rate is inversely proportional to the Lundquist number, S, and the viscous one to the Reynolds number, R. The time decay exponent is proportional to the sum (1/S + 1/R).

  14. Geothermal energy: clean power from the Earth's heat

    USGS Publications Warehouse

    Duffield, Wendell A.; Sass, John H.

    2003-01-01

    Societies in the 21st century require enormous amounts of energy to drive the machines of commerce and to sustain the lifestyles that many people have come to expect. Today, most of this energy is derived from oil, natural gas, and coal, supplemented by nuclear power. Local exceptions exist, but oil is by far the most common source of energy worldwide. Oil resources, however, are nonrenewable and concentrated in only a few places around the globe, creating uncertainty in long-term supply for many nations. At the time of the Middle East oil embargo of the 1970s, about a third of the United States oil supply was imported, mostly from that region. An interruption in the flow of this import disrupted nearly every citizen’s daily life, as well as the Nation’s economy. In response, the Federal Government launched substantial programs to accelerate development of means to increasingly harness “alternative energies”—primarily biomass, geothermal, solar, and wind. The new emphasis on simultaneously pursuing development of several sources of energy recognized the timeless wisdom found in the proverb of “not putting all eggs in one basket.” This book helps explain the role that geothermal resources can play in helping promote such diversity and in satisfying our Nation’s vast energy needs as we enter a new millennium. For centuries, people have enjoyed the benefits of geothermal energy available at hot springs, but it is only through technological advances made during the 20th century that we can tap this energy source in the subsurface and use it in a variety of ways, including the generation of electricity. Geothermal resources are simply exploitable concentrations of the Earth’s natural heat (thermal energy). The Earth is a bountiful source of thermal energy, continuously producing heat at depth, primarily by the decay of naturally occurring radioactive isotopes—principally of uranium, thorium, and potassium—that occur in small amounts in all rocks

  15. Spatial Scale Gaps of Turbulent Heat Fluxes in Arctic Tundra

    NASA Astrophysics Data System (ADS)

    Fochesatto, G. J.; Gruber, M. A.; Cristóbal-Rosselló, J.; Edgar, C.; Kane, D. L.

    2013-12-01

    Large-area averaged turbulent fluxes of scalars (heat and carbon) play an important role in climate and ecosystem models by resolving the scale-gap closure defining top-down and bottom-up scaling schemes. Large Aperture Scintillometer (LAS) measurement of the refractive index structure function (CN2) allows for indirect retrieval of area-averaged (>km2) atmospheric boundary layer sensible heat fluxes. In this work we report observations of LAS in Arctic tundra at Imnavait Creek Basin. LAS-derived fluxes are compared to more localized measurements of heat fluxes obtained by an eddy-covariance (EC) system distributed across the basin. This article discusses the divergence observed in the temporal series of LAS-fluxes in comparison to spatially distributed measurements of EC-fluxes. The comparison stresses the role of the Arctic ABL structure, terrain-flow characteristics and radiative fluxes in the overall spatial representation of fluxes.

  16. Biodegradability and ecotoxicity of commercially available geothermal heat transfer fluids

    NASA Astrophysics Data System (ADS)

    Schmidt, Kathrin R.; Körner, Birgit; Sacher, Frank; Conrad, Rachel; Hollert, Henner; Tiehm, Andreas

    2016-03-01

    Commercially available heat transfer fluids used in borehole heat exchangers were investigated for their composition, their biodegradability as well as their ecotoxicity. The main components of the fluids are organic compounds (often glycols) for freezing protection. Biodegradation of the fluids in laboratory studies caused high oxygen depletion as well as nitrate/iron(III) reduction under anaerobic conditions. Additives such as benzotriazoles for corrosion protection were persistent. Ecotoxicity data show that the commercially available fluids caused much higher ecotoxicity than their main organic constituents. Consequently, with regard to groundwater protection pure water as heat transfer medium is recommended. The second best choice is the usage of glycols without any additives. Effects on groundwater quality should be considered during ecological-economical cost-benefit-analyses of further geothermal energy strategies. The protection of groundwater as the most important drinking water resource must take priority over the energy gain from aquifers.

  17. Transient critical heat flux and blowdown heat-transfer studies

    SciTech Connect

    Leung, J.C.

    1980-05-01

    Objective of this study is to give a best-estimate prediction of transient critical heat flux (CHF) during reactor transients and hypothetical accidents. To accomplish this task, a predictional method has been developed. Basically it involves the thermal-hydraulic calculation of the heated core with boundary conditions supplied from experimental measurements. CHF predictions were based on the instantaneous ''local-conditions'' hypothesis, and eight correlations (consisting of round-tube, rod-bundle, and transient correlations) were tested against most recent blowdown heat-transfer test data obtained in major US facilities. The prediction results are summarized in a table in which both CISE and Biasi correlations are found to be capable of predicting the early CHF of approx. 1 s. The Griffith-Zuber correlation is credited for its prediction of the delay CHF that occurs in a more tranquil state with slowly decaying mass velocity. In many instances, the early CHF can be well correlated by the x = 1.0 criterion; this is certainly indicative of an annular-flow dryout-type crisis. The delay CHF occurred at near or above 80% void fraction, and the success of the modified Zuber pool-boiling correlation suggests that this CHF is caused by flooding and pool-boiling type hydrodynamic crisis.

  18. Geothermal heating enhances atmospheric asymmetries on synchronously rotating planets

    NASA Astrophysics Data System (ADS)

    Haqq-Misra, Jacob; Kopparapu, Ravi Kumar

    2015-01-01

    Earth-like planets within the liquid water habitable zone of M-type stars may evolve into synchronous rotators. On these planets, the substellar hemisphere experiences perpetual daylight while the opposing antistellar hemisphere experiences perpetual darkness. Because the night-side hemisphere has no direct source of energy, the air over this side of the planet is prone to freeze out and deposit on the surface, which could result in atmospheric collapse. However, general circulation models (GCMs) have shown that atmospheric dynamics can counteract this problem and provide sufficient energy transport to the antistellar side. Here, we use an idealized GCM to consider the impact of geothermal heating on the habitability of synchronously rotating planets. Geothermal heating may be expected due to tidal interactions with the host star, and the effects of geothermal heating provide additional habitable surface area and may help to induce melting of ice on the antistellar hemisphere. We also explore the persistence of atmospheric asymmetries between the Northern and Southern hemispheres, and we find that the direction of the meridional circulation (for rapidly rotating planets) or the direction of zonal wind (for slowly rotating planets) reverses on either side of the substellar point. We show that the zonal circulation approaches a theoretical state similar to a Walker circulation only for slowly rotating planets, while rapidly rotating planets show a zonal circulation with the opposite direction. We find that a cross-polar circulation is present in all cases and provides an additional mechanism of mass and energy transport from the substellar to antistellar point. Characterization of the atmospheres of synchronously rotating planets should include consideration of hemispheric differences in meridional circulation and examination of transport due to cross-polar flow.

  19. Human Health Science Building Geothermal Heat Pump Systems

    SciTech Connect

    Leidel, James

    2014-12-22

    The grant objectives of the DOE grant funded project have been successfully completed. The Human Health Building (HHB) was constructed and opened for occupancy for the Fall 2012 semester of Oakland University. As with any large construction project, some issues arose which all were overcome to deliver the project on budget and on time. The facility design is a geothermal / solar-thermal hybrid building utilizing both desiccant dehumidification and variable refrigerant flow heat pumps. It is a cooling dominant building with a 400 ton cooling design day load, and 150 ton heating load on a design day. A 256 vertical borehole (320 ft depth) ground source heat pump array is located south of the building under the existing parking lot. The temperature swing and performance over 2013 through 2015 shows the ground loop is well sized, and may even have excess capacity for a future building to the north (planned lab facility). The HHB achieve a US Green Building Counsel LEED Platinum rating by collecting 52 of the total 69 available LEED points for the New Construction v.2 scoring checklist. Being Oakland's first geothermal project, we were very pleased with the building outcome and performance with the energy consumption approximately 1/2 of the campus average facility, on a square foot basis.

  20. Fractured geothermal reservoir growth induced by heat extraction

    SciTech Connect

    Tester, J.W.; Murphy, H.D.; Grigsby, C.O.; Robinson, B.A.; Potter, R.M.

    1986-01-01

    Field testing of a hydraulically-stimulated, hot dry rock geothermal system at the Fenton Hill site in northern New Mexico has indicated that significant reservoir growth occurred as energy was extracted. Tracer, microseismic, and geochemical measurements provided the primary quantitative evidence for documenting the increases in accessible reservoir volume and fractured rock surface area that were observed during energy extraction operations which caused substantial thermal drawdown in portions of the reservoir. These temporal increases suggest that augmentation of reservoir heat production capacity in hot dry rock systems may be possible.

  1. Compact, Deep-Penetrating Geothermal Heat Flow Instrumentation for Lunar Landers

    NASA Technical Reports Server (NTRS)

    Nagihara, S.; Zacny, K.; Hedlund, M.; Taylor, P. T.

    2012-01-01

    Geothermal heat flow is obtained as a product of the two separate measurements of geothermal gradient in, and thermal conductivity of, the vertical soi/rock/regolith interval penetrated by the instrument. Heat flow measurements are a high priority for the geophysical network missions to the Moon recommended by the latest Decadal Survey [I] and previously the International Lunar Network [2]. The two lunar-landing missions planned later this decade by JAXA [3] and ESA [4] also consider geothermal measurements a priority.

  2. Modeling studies of heat transfer and phase distribution in two-phase geothermal reservoirs

    SciTech Connect

    Lai, C.H.; Bodvarsson, G.S.; Truesdell, A.H. . Earth Sciences Div.)

    1994-02-01

    Phase distribution as well as mass flow and heat transfer behavior in two-phase geothermal systems have been studied by numerical modeling. A two-dimensional porous-slab model was used with a non-uniform heat flux boundary conditions at the bottom. Steady-state solutions are obtained for the phase distribution and heat transfer behavior for cases with different mass of fluid (gas saturation) in place, permeabilities, and capillary pressures. The results obtained show very efficient heat transfer in the vapor-dominated zone due to the development of heat pipes and near-uniform saturations. The phase distribution below the vapor-dominated zone depends on permeability. For relatively high-permeability systems, single-phase liquid zones prevail, with convection providing the energy throughput. For lower permeability systems, a two-phase liquid-dominated zone develops, because single-phase liquid convection is not sufficient to dissipate heat released from the source. These results are consistent with observations from the field, where most high-temperature liquid-dominated two-phase systems have relatively low permeabilities e.g. Krafla, Iceland; Kenya; Baca, New Mexico. The numerical results obtained also show that for high heat flow a high-temperature single-phase vapor zone can develop below a typical (240 C) vapor-dominated zone, as has recently been found at the Geysers, California, and Larderello, Italy.

  3. Thin Film Heat Flux Sensor of Improved Design

    NASA Technical Reports Server (NTRS)

    Fralick, Gus; Wrbanek, John; Blaha, Charles

    2002-01-01

    A new design for a thin film heat flux sensor is presented. It is easier to fabricate than previous designs, for a given heat flux has an order of magnitude larger signal, and is more easily scalable than previous designs. Transient and steady state data are also presented.

  4. Evaluation of a new, perforated heat flux plate design

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Accurate measurement of heat flux is essential to optimize structural and process design and to improve understanding of energy transfer in natural systems. Laboratory and field experiments evaluated the performance of a new, perforated heat flux plate designed for environmental applications. Labora...

  5. Tracking heat flux sensors for concentrating solar applications

    DOEpatents

    Andraka, Charles E; Diver, Jr., Richard B

    2013-06-11

    Innovative tracking heat flux sensors located at or near the solar collector's focus for centering the concentrated image on a receiver assembly. With flux sensors mounted near a receiver's aperture, the flux gradient near the focus of a dish or trough collector can be used to precisely position the focused solar flux on the receiver. The heat flux sensors comprise two closely-coupled thermocouple junctions with opposing electrical polarity that are separated by a thermal resistor. This arrangement creates an electrical signal proportional to heat flux intensity, and largely independent of temperature. The sensors are thermally grounded to allow a temperature difference to develop across the thermal resistor, and are cooled by a heat sink to maintain an acceptable operating temperature.

  6. CO{sub 2} flux measurements across portions of the Dixie Valley geothermal system, Nevada

    SciTech Connect

    Bergfeld, D.; Goff, F.; Janik, C.J.; Johnson, S.D.

    1998-12-31

    A map of the CO{sub 2} flux across a newly formed area of plant kill in the NW part of the Dixie Valley geothermal system was constructed to monitor potential growth of a fumarole field. Flux measurements were recorded using a LI-COR infrared analyzer. Sample locations were restricted to areas within and near the dead zone. The data delineate two areas of high CO{sub 2} flux in different topographic settings. Older fumaroles along the Stillwater range front produce large volumes of CO{sub 2} at high temperatures. High CO{sub 2} flux values were also recorded at sites along a series of recently formed ground fractures at the base of the dead zone. The two areas are connected by a zone of partial plant kill and moderate flux on an alluvial fan. Results from this study indicate a close association between the range front fumaroles and the dead zone fractures. The goals of this study are to characterize recharge to the geothermal system, provide geochemical monitoring of reservoir fluids and to examine the temporal and spatial distribution of the CO{sub 2} flux in the dead zone. This paper reports the results of the initial CO{sub 2} flux measurements taken in October, 1997.

  7. Natural analogs for enhanced heat recovery from geothermal systems

    SciTech Connect

    Nielson, D.L.

    1996-12-31

    High-temperature hydrothermal systems are physically and chemically zoned with depth. The energy input is from a magmatic zone, intruded by igneous bodies, that may also contribute variable amounts of magmatic fluid to the system. The heat source is directly overlain by a section of rocks, that due to their elevated temperature, respond to stress in a ductile fashion. The ductile zone is, in turn, overlain by a section of rocks that respond to stress in a brittle fashion, where water is able to circulate through fractures (the geothermal reservoir) and will be termed the hydrothermal circulation zone. Ancient and modern high-temperature geothermal systems show a predictable sequence of evolutionary events affecting these stratified zones. Metamorphic core complexes are uplifts, formed in highly extended terrains, that expose fossil brittle-ductile transition zones. Formerly ductile rocks have had brittle fractures superimposed on them, and meteoric hydrothermal systems are associated with the brittle fracturing. Porphyry copper deposits typically evolve from magmatic to meteoric hydrothermal systems. At the Larderello geothermal system, the brittle-ductile transition has been mapped using reflection seismology, and the zone has been penetrated by the San Pompeo 2 well where temperatures >420{degrees}C were encountered. Although neo-granitic dikes have been penetrated by drilling in the Larderello area, the brittle-ductile transition is largely above the inferred plutonic heat source. In the Geysers system, in contrast, the present steam system has been superimposed on young plutonic rocks and the inferred brittle-ductile transition is present at a depth of about 4.7 km within the plutonic rocks. As hydrothermal reservoirs are depleted, or surface facilities are restricted by environmental considerations, interest will turn to the deeper portions of known systems. Japan already has an aggressive program to develop Deep-Seated and Magma-Ambient resources.

  8. Development of heat flux sensors for turbine airfoils

    NASA Astrophysics Data System (ADS)

    Atkinson, William H.; Cyr, Marcia A.; Strange, Richard R.

    1985-10-01

    The objectives of this program are to develop heat flux sensors suitable for installation in hot section airfoils of advanced aircraft turbine engines and to experimentally verify the operation of these heat flux sensors in a cylinder in a cross flow experiment. Embedded thermocouple and Gardon gauge sensors were developed and fabricated into both blades and vanes. These were then calibrated using a quartz lamp bank heat source and finally subjected to thermal cycle and thermal soak testing. These sensors were also fabricated into cylindrical test pieces and tested in a burner exhaust to verify heat flux measurements produced by these sensors. The results of the cylinder in cross flow tests are given.

  9. Uncertainty estimates in global ocean surface heat fluxes

    SciTech Connect

    Gleckler, P.J.

    1992-11-01

    To date the only practical means of estimating large scale ocean surface heat fluxes is with bulk parameterization formulae. It is well known that there are many sources of uncertainties in such estimates due to sampling deficiencies, uncertainties in the field measurements and uncertainties in the parameterizations themselves. This report presents global estimates of the total uncertainties in the climatological annual mean net shortwave (SW), net longwave (LW), latent heat (LH) and sensible heat (SH) ocean surface heat fluxes. The flux estimates used here were compiled by Oberhuber (1988), which utilize the Monthly Summed Trimmed COADS 1950--1979 data.

  10. Auxiliary Heating of Geothermally Preheated Water or CO2 - A Potential Solution for Low- to Moderate-Temperature Geothermal Resources

    NASA Astrophysics Data System (ADS)

    Kong, X.; Garapati, N.; Adams, B. M.; Randolph, J.; Kuehn, T. H.; Saar, M. O.

    2015-12-01

    Typically, low- to moderate-temperature geothermal resources are more effectively used for direct heat energy applications. However, due to high thermal losses during transport, direct use requires that the heat resource is located near the user. Alternatively, we show here that if such a low-temperature geothermal resource is combined with an additional or secondary energy resource, the power production is increased compared to the sum from two separate (geothermal and secondary fuel) power plants (DiPippo et al. 1978) and the thermal losses are minimized because the thermal energy is utilized where it is produced. Since Adams et al. (2015) found that using CO2 as a subsurface working fluid produces more net power than brine at low- to moderate-temperature geothermal resource conditions, we compare over a range of parameters the net power and efficiencies of hybrid geothermal power plants that use brine or CO2 as the subsurface working fluid, that are then heated further with a secondary energy source that is unspecified here. Parameters varied include the subsurface working fluid (brine vs. CO2), geothermal reservoir depth (2.5-4.5 km), and turbine inlet temperature (200-600°C) after auxiliary heating. The hybrid power plant is numerically modeled using an iterative coupling approach of TOUGH2-ECO2N/ECO2H (Pruess, 2004) for simulation of the subsurface reservoir and Engineering Equation Solver for well bore fluid flow and surface power plant performance. We find that hybrid power plants that are CO2-based (subsurface) systems have higher thermal efficiencies than the brine based systems at low turbine inlet temperatures. Specifically, our results indicate that geothermal hybrid plants that are CO2-based are more efficient than brine-based systems when the contribution of the geothermal resource energy is higher than 48%.

  11. Geothermal direct-heat utilization assistance. Quarterly project progress report, July 1996--September 1996. Federal Assistance Program

    SciTech Connect

    Lienau, P.

    1996-11-01

    This report summarizes geothermal technical assistance, R&D and technology transfer activities of the Geo-Heat Center at Oregon Institute of Technology for the fourth quarter of FY-96. It describes 152 contacts with parties during this period related to technical assistance with geothermal direct heat projects. Areas dealt with include geothermal heat pumps, space heating, greenhouses, aquaculture, equipment, economics and resources. Research activities are summarized on greenhouse peaking. Outreach activities include the publication of a geothermal direct use Bulletin, dissemination of information, geothermal library, technical papers and seminars, and progress monitor reports on geothermal resources and utilization.

  12. Miniature convection cooled plug-type heat flux gauges

    NASA Astrophysics Data System (ADS)

    Liebert, Curt H.

    1994-02-01

    Tests and analysis of a new miniature plug-type heat flux gauge configuration are described. This gauge can simultaneously measure heat flux on two opposed active surfaces when heat flux levels are equal to or greater than about 0.2 MW/m(sup 2). The performance of this dual active surface gauge was investigated over a wide transient and steady heat flux and temperature range. The tests were performed by radiatively heating the front surface with an argon arc lamp while the back surface was convection cooled with air. Accuracy is about +20 percent. The gauge is responsive to fast heat flux transients and is designed to withstand the high temperature (1300 K), high pressure (15 MPa), erosive and corrosive environments in modern engines. This gauge can be used to measure heat flux on the surfaces of internally cooled apparatus such as turbine blades and combustors used in jet propulsion systems and on the surfaces of hypersonic vehicles. Heat flux measurement accuracy is not compromised when design considerations call for various size gauges to be fabricated into alloys of various shapes and properties. Significant gauge temperature reductions (120 K), which can lead to potential gauge durability improvement, were obtained when the gauges were air-cooled by forced convection.

  13. Miniature Convection Cooled Plug-type Heat Flux Gauges

    NASA Technical Reports Server (NTRS)

    Liebert, Curt H.

    1994-01-01

    Tests and analysis of a new miniature plug-type heat flux gauge configuration are described. This gauge can simultaneously measure heat flux on two opposed active surfaces when heat flux levels are equal to or greater than about 0.2 MW/m(sup 2). The performance of this dual active surface gauge was investigated over a wide transient and steady heat flux and temperature range. The tests were performed by radiatively heating the front surface with an argon arc lamp while the back surface was convection cooled with air. Accuracy is about +20 percent. The gauge is responsive to fast heat flux transients and is designed to withstand the high temperature (1300 K), high pressure (15 MPa), erosive and corrosive environments in modern engines. This gauge can be used to measure heat flux on the surfaces of internally cooled apparatus such as turbine blades and combustors used in jet propulsion systems and on the surfaces of hypersonic vehicles. Heat flux measurement accuracy is not compromised when design considerations call for various size gauges to be fabricated into alloys of various shapes and properties. Significant gauge temperature reductions (120 K), which can lead to potential gauge durability improvement, were obtained when the gauges were air-cooled by forced convection.

  14. Comparison of observed and general circulation model derived continental subsurface heat flux in the Northern Hemisphere

    NASA Astrophysics Data System (ADS)

    MacDougall, Andrew H.; Beltrami, Hugo; GonzáLez-Rouco, J. Fidel; Stevens, M. Bruce; Bourlon, Evelise

    2010-06-01

    Heat fluxes in the continental subsurface were estimated from general circulation model (GCM) simulations of the climate of the last millennium and compared to those obtained from subsurface geothermal data. Since GCMs have bottom boundary conditions (BBCs) that are less than 10 m deep and thus may be thermodynamically restricted in the continental subsurface, we used an idealized land surface model (LSM) with a very deep BBC to estimate the potential for realistic subsurface heat storage in the absence of bottom boundary constraints. Results indicate that there is good agreement between observed fluxes and GCM simulated fluxes for the 1780-1980 period when the GCM simulated temperatures are coupled to the LSM with deep BBC. These results emphasize the importance of placing a deep BBC in GCM soil components for the proper simulation of the overall continental heat budget. In addition, the agreement between the LSM surface fluxes and the borehole temperature reconstructed fluxes lends additional support to the overall quality of the GCM (ECHO-G) paleoclimatic simulations.

  15. Studies of geothermal power and process heat applications in St. Lucia and Guatemala

    SciTech Connect

    Altseimer, J.H.; Edeskuty, F.J.

    1986-01-01

    Many countries have the potential to use geothermal energy for both power production and process heat applications. Two Los Alamos programs have studied the most effective use of geothermal energy in St. Lucia and Guatemala. The general objectives are (1) to reduce oil imports; (2) develop employment opportunities; and (3) make products more competitive. The initial St. Lucia studies emphasized power generation but a number of applications for the power plant's residual heat were also found and costs and systems have been determined. The costs of geothermal heat compare favorably with heat from other sources such as oil. In Guatemala, the development of the nation's first geothermal field is well advanced. Process heat applications and their coordination with power generation plants are being studied at Los Alamos. Guatemala has at least two fields that appear suitable for power and heat production. These fields are close to urban centers and to many potential heat applications.

  16. Research and Development of Information on Geothermal Direct Heat Application Projects

    SciTech Connect

    Hederman, William F., Jr.; Cohen, Laura A.

    1981-10-01

    This is the first annual report of ICF's geothermal R&D project for the Department of Energy's Idaho Operations Office. The overall objective of this project is to compile, analyze, and report on data from geothermal direct heat application projects. Ultimately, this research should convey the information developed through DOE's and Program Opportunity Notice (PON) activities as well as through other pioneering geothermal direct heat application projects to audiences which can use the early results in new, independent initiatives. A key audience is potential geothermal investors.

  17. Geothermal Frontier: Penetrate a boundary between hydrothermal convection and heat conduction zones to create 'Beyond Brittle Geothermal Reservoir'

    NASA Astrophysics Data System (ADS)

    Tsuchiya, N.; Asanuma, H.; Sakaguchi, K.; Okamoto, A.; Hirano, N.; Watanabe, N.; Kizaki, A.

    2013-12-01

    EGS has been highlightened as a most promising method of geothermal development recently because of applicability to sites which have been considered to be unsuitable for geothermal development. Meanwhile, some critical problems have been experimentally identified, such as low recovery of injected water, difficulties to establish universal design/development methodology, and occurrence of large induced seismicity. Future geothermal target is supercritical and superheated geothermal fluids in and around ductile rock bodies under high temperatures. Ductile regime which is estimated beyond brittle zone is target region for future geothermal development due to high enthalpy fluids and relatively weak water-rock interaction. It is very difficult to determine exact depth of Brittle-Ductile boundary due to strong dependence of temperature (geotherm) and strain rate, however, ductile zone is considered to be developed above 400C and below 3 km in geothermal fields in Tohoku District. Hydrothermal experiments associated with additional advanced technology will be conducting to understand ';Beyond brittle World' and to develop deeper and hotter geothermal reservoir. We propose a new concept of the engineered geothermal development where reservoirs are created in ductile basement, expecting the following advantages: (a)simpler design and control the reservoir, (b)nearly full recovery of injected water, (c)sustainable production, (d)cost reduction by development of relatively shallower ductile zone in compression tectonic zones, (e)large quantity of energy extraction from widely distributed ductile zones, (f)establishment of universal and conceptual design/development methodology, and (g) suppression of felt earthquakes from/around the reservoirs. In ductile regime, Mesh-like fracture cloud has great potential for heat extraction between injection and production wells in spite of single and simple mega-fracture. Based on field observation and high performance hydrothermal

  18. Geothermal direct-heat utilization assistance. Quarterly project progress report, October--December 1997

    SciTech Connect

    1997-01-01

    This report summarizes geothermal technical assistance, R and D and technology transfer activities of the Geo-Heat Center at Oregon Institute of Technology for the first quarter of FY-98 (October--December 1997). It describes 216 contacts with parties during this period related to technical assistance with geothermal direct heat projects. Areas dealt with include requests for general information including maps and material for high school debates, and material on geothermal heat pumps, resource and well data, space heating and cooling, greenhouses, aquaculture, equipment, district heating, resorts and spas, industrial applications, electric power and snow melting. Research activities include work on model construction specifications of lineshaft submersible pumps and plate heat exchangers, a comprehensive aquaculture developer package and revisions to the Geothermal Direct Use Engineering and Design Guidebook. Outreach activities include the publication of the Quarterly Bulletin (Vol. 18, No. 4) which was devoted entirely to geothermal activities in South Dakota, dissemination of information mainly through mailings of publications, tours of local geothermal uses, geothermal library acquisition and use, participation in workshops, short courses and technical meetings by the staff, and progress monitor reports on geothermal activities.

  19. Supercritical convection, critical heat flux, and coking characteristics of propane

    NASA Technical Reports Server (NTRS)

    Rousar, D. C.; Gross, R. S.; Boyd, W. C.

    1984-01-01

    The heat transfer characteristics of propane at subcritical and supercritical pressure were experimentally evaluated using electrically heated Monel K-500 tubes. A design correlation for supercritical heat transfer coefficient was established using the approach previously applied to supercritical oxygen. Flow oscillations were observed and the onset of these oscillations at supercritical pressures was correlated with wall-to-bulk temperature ratio and velocity. The critical heat flux measured at subcritical pressure was correlated with the product of velocity and subcooling. Long duration tests at fixed heat flux conditions were conducted to evaluate coking on the coolant side tube wall and coking rates comparable to RP-1 were observed.

  20. Environmental Assessment: geothermal direct heat project, Marlin, Texas

    SciTech Connect

    Not Available

    1980-08-01

    The Federal action addressed by this Environmental Assessment (EA) is joint funding the retrofitting of a heating and hot water system in a hospital at Marlin, Texas, with a geothermal preheat system. The project will be located within the existing hospital boiler room. One supply well was drilled in an existing adjacent parking lot. It was necessary to drill the well prior to completion of this environmental assessment in order to confirm the reservoir and to obtain fluids for analysis in order to assess the environmental effects of fluid disposal. Fluid from operation will be disposed of by discharging it directly into existing street drains, which will carry the fluid to Park Lake and eventually the Brazos River. Fluid disposal activities are regulated by the Texas Railroad Commission. The local geology is determined by past displacements in the East Texas Basin. Boundaries are marked by the Balcones and the Mexia-Talco fault systems. All important water-bearing formations are in the cretaceous sedimentary rocks and are slightly to highly saline. Geothermal fluids are produced from the Trinity Group; they range from approximately 3600 to 4000 ppM TDS. Temperatures are expected to be above 64/sup 0/C (147/sup 0/F). Surface water flows southeastward as a part of the Brazos River Basin. The nearest perennial stream is the Brazos River 5.6 km (3.5 miles) away, to which surface fluids will eventually discharge. Environmental impacts of construction were small because of the existing structures and paved areas. Construction run-off and geothermal flow-test fluid passed through a small pond in the city park, lowering its water quality, at least temporarily. Construction noise was not out of character with existing noises around the hospital.

  1. Experimental feasibility study of a thermoelectric heat flux gage

    NASA Technical Reports Server (NTRS)

    Vanfossen, G. J.; Lopez, I.

    1983-01-01

    An experiment was conducted to determine the feasibility of using a commercially available thermoelectric device as a heat flux gage at near ambient conditions. In certain research applications, the thermoelectric heat flux gage can provide a relatively simple means to model a warm fluid cold wall convection environment. The experiment showed that heat flux through the gage could be correlated within 2.5 percent with a simple algebraic equation which considered the thermoelectric current through the device and the hot and cold side temperatures.

  2. Geothermal technology transfer for direct heat applications: Final report, 1983--1988

    SciTech Connect

    Lienau, P.J.; Culver, G.

    1988-01-01

    This report describes a geothermal technology transfer program, performed by Oregon Institute of Technology's Geo-Heat Center, used to aid in the development of geothermal energy for direct heat applications. It provides a summary of 88 technical assistance projects performed in 10 states for space heating, district heating, green-houses, aquaculture, industrial processing, small scale binary electric power generation and heat pump applications. It describes an inventory compiled for over 100 direct heat projects that contains information on project site, resource and engineering data. An overview of information services is provided to users of the program which includes; advisory, referrals, literature distribution, geothermal technology library, quarterly Bulletin, training programs, presentations and tours, and reporting of activities for the USDOE Geothermal Progress Monitor.

  3. Feasibility study for geothermal-water space heating for the Safford Federal Prison Camp, Safford, Arizona

    SciTech Connect

    Not Available

    1981-07-01

    The results of an economic feasibility study for the Oregon Institute of Technology regarding a geothermal heating system for the Federal Prison Camp, Safford, Arizona are presented. The following aspects were examined: heat load calculations of the buildings involved; mechanical equipment retrofits necessary to accept geothermal water for the purpose of space heating; cost estimates for the equipment retrofit; and evaluation of the equipment retrofit to determine economic feasibility.

  4. Tropical Gravity Wave Momentum Fluxes and Latent Heating Distributions

    NASA Technical Reports Server (NTRS)

    Geller, Marvin A.; Zhou, Tiehan; Love, Peter T.

    2015-01-01

    Recent satellite determinations of global distributions of absolute gravity wave (GW) momentum fluxes in the lower stratosphere show maxima over the summer subtropical continents and little evidence of GW momentum fluxes associated with the intertropical convergence zone (ITCZ). This seems to be at odds with parameterizations forGWmomentum fluxes, where the source is a function of latent heating rates, which are largest in the region of the ITCZ in terms of monthly averages. The authors have examined global distributions of atmospheric latent heating, cloud-top-pressure altitudes, and lower-stratosphere absolute GW momentum fluxes and have found that monthly averages of the lower-stratosphere GW momentum fluxes more closely resemble the monthly mean cloud-top altitudes rather than the monthly mean rates of latent heating. These regions of highest cloud-top altitudes occur when rates of latent heating are largest on the time scale of cloud growth. This, plus previously published studies, suggests that convective sources for stratospheric GW momentum fluxes, being a function of the rate of latent heating, will require either a climate model to correctly model this rate of latent heating or some ad hoc adjustments to account for shortcomings in a climate model's land-sea differences in convective latent heating.

  5. Screening for heat transport by groundwater in closed geothermal systems.

    PubMed

    Ferguson, Grant

    2015-01-01

    Heat transfer due to groundwater flow can significantly affect closed geothermal systems. Here, a screening method is developed, based on Peclet numbers for these systems and Darcy's law. Conduction-only conditions should not be expected where specific discharges exceed 10(-8)  m/s. Constraints on hydraulic gradients allow for preliminary screening for advection based on rock or soil types. Identification of materials with very low hydraulic conductivity, such as shale and intact igneous and metamorphic rock, allow for analysis with considering conduction only. Variability in known hydraulic conductivity allows for the possibility of advection in most other rocks and soil types. Further screening relies on refinement of estimates of hydraulic gradients and hydraulic conductivity through site investigations and modeling until the presence or absence of conduction can be confirmed.

  6. Screening for heat transport by groundwater in closed geothermal systems.

    PubMed

    Ferguson, Grant

    2015-01-01

    Heat transfer due to groundwater flow can significantly affect closed geothermal systems. Here, a screening method is developed, based on Peclet numbers for these systems and Darcy's law. Conduction-only conditions should not be expected where specific discharges exceed 10(-8)  m/s. Constraints on hydraulic gradients allow for preliminary screening for advection based on rock or soil types. Identification of materials with very low hydraulic conductivity, such as shale and intact igneous and metamorphic rock, allow for analysis with considering conduction only. Variability in known hydraulic conductivity allows for the possibility of advection in most other rocks and soil types. Further screening relies on refinement of estimates of hydraulic gradients and hydraulic conductivity through site investigations and modeling until the presence or absence of conduction can be confirmed. PMID:24438345

  7. Spatial resolution of anthropogenic heat fluxes into urban aquifers.

    PubMed

    Benz, Susanne A; Bayer, Peter; Menberg, Kathrin; Jung, Stephan; Blum, Philipp

    2015-08-15

    Urban heat islands in the subsurface contain large quantities of energy in the form of elevated groundwater temperatures caused by anthropogenic heat fluxes (AHFS) into the subsurface. The objective of this study is to quantify these AHFS and the heat flow they generate in two German cities, Karlsruhe and Cologne. Thus, statistical and spatial analytical heat flux models were developed for both cities. The models include the spatial representation of various sources of AHFS: (1) elevated ground surface temperatures, (2) basements, (3) sewage systems, (4) sewage leakage, (5) subway tunnels, and (6) district heating networks. The results show that the district heating networks induce the largest AHFS with values greater than 60 W/m(2) and one order of magnitude higher than fluxes from other sources. A covariance analysis indicates that the spatial distribution of the total flux depends mainly on the thermal gradient in the unsaturated zone. On a citywide scale, basements and elevated ground surface temperatures are the dominant sources of heat flow. Overall, 2.1 PJ/a and 1.0 PJ/a of heat are accumulated on average in Karlsruhe and the western part of Cologne, respectively. Extracting this anthropogenically originated energy could sustainably supply significant parts of the urban heating demand. Furthermore, using this heat could also keep groundwater temperatures from rising further.

  8. Spatial resolution of anthropogenic heat fluxes into urban aquifers.

    PubMed

    Benz, Susanne A; Bayer, Peter; Menberg, Kathrin; Jung, Stephan; Blum, Philipp

    2015-08-15

    Urban heat islands in the subsurface contain large quantities of energy in the form of elevated groundwater temperatures caused by anthropogenic heat fluxes (AHFS) into the subsurface. The objective of this study is to quantify these AHFS and the heat flow they generate in two German cities, Karlsruhe and Cologne. Thus, statistical and spatial analytical heat flux models were developed for both cities. The models include the spatial representation of various sources of AHFS: (1) elevated ground surface temperatures, (2) basements, (3) sewage systems, (4) sewage leakage, (5) subway tunnels, and (6) district heating networks. The results show that the district heating networks induce the largest AHFS with values greater than 60 W/m(2) and one order of magnitude higher than fluxes from other sources. A covariance analysis indicates that the spatial distribution of the total flux depends mainly on the thermal gradient in the unsaturated zone. On a citywide scale, basements and elevated ground surface temperatures are the dominant sources of heat flow. Overall, 2.1 PJ/a and 1.0 PJ/a of heat are accumulated on average in Karlsruhe and the western part of Cologne, respectively. Extracting this anthropogenically originated energy could sustainably supply significant parts of the urban heating demand. Furthermore, using this heat could also keep groundwater temperatures from rising further. PMID:25930242

  9. Thin-Film Resistance Heat-Flux Sensors

    NASA Technical Reports Server (NTRS)

    Fralick, Gustave C.; Wrbanek, John D.; Blaha, Charles A.

    2005-01-01

    Thin-film heat-flux sensors of a proposed type would offer advantages over currently available thin-film heat flux sensors. Like a currently available thin-film heat-flux sensor, a sensor according to the proposal would be based on measurement of voltages related to the temperatures of thin metal films on the hotter and colder faces of a layer of an electrically insulating and moderately thermally conductive material. The heat flux through such a device is proportional to the difference between the temperatures and to the thermal conductivity of the layer. The advantages of the proposed sensors over the commercial ones would arise from the manner in which the temperature-related voltages would be generated and measured.

  10. Recovery Act - Geothermal Technologies Program: Ground Source Heat Pumps Final Scientific/Technical Report

    SciTech Connect

    Nick Rosenberry, Harris Companies

    2012-05-04

    A large centralized geothermal heat pump system was installed to provide ice making, space cooling, space heating, process water heating, and domestic hot water heating for an ice arena in Eagan Minnesota. This paper provides information related to the design and construction of the project. Additionally, operating conditions for 12 months after start-up are provided.

  11. Wind-Speed—Surface-Heat-Flux Feedback in Dust Devils

    NASA Astrophysics Data System (ADS)

    Ito, Junshi; Niino, Hiroshi

    2016-06-01

    Strong winds associated with dust devils can induce locally large heat fluxes from the surface, and resulting enhanced buoyancy may further intensify the dust devils. This positive wind—surface-heat-flux feedback is studied using a large-eddy simulation of a convective boundary layer. A comparison of the results with and without the feedback process for the same environment demonstrates the significance of the feedback process for simulated dust devils.

  12. Wind-Speed—Surface-Heat-Flux Feedback in Dust Devils

    NASA Astrophysics Data System (ADS)

    Ito, Junshi; Niino, Hiroshi

    2016-11-01

    Strong winds associated with dust devils can induce locally large heat fluxes from the surface, and resulting enhanced buoyancy may further intensify the dust devils. This positive wind—surface-heat-flux feedback is studied using a large-eddy simulation of a convective boundary layer. A comparison of the results with and without the feedback process for the same environment demonstrates the significance of the feedback process for simulated dust devils.

  13. MHD instabilities of collisionless space plasma with heat fluxes

    NASA Astrophysics Data System (ADS)

    Kuznetsov, V. D.; Dzhalilov, N. S.

    2014-12-01

    Properties of instabilities in a collisionless plasma are considered based on 16-moment MHD equations with allowance for differences between the heat fluxes along the magnetic field due to longitudinal and transverse thermal ion motions. It is shown that the increments and thresholds appreciably depend on these two heat fluxes for all compressible instabilities arising in the MHD approach (second compressible fire-hose, mirror, and thermal instabilities).

  14. Divertor Heat Flux Mitigation in the National Spherical Torus Experiment

    SciTech Connect

    Soukhanovskii, V A; Maingi, R; Gates, D A; Menard, J E; Paul, S F; Raman, R; Roquemore, A L; Bell, M G; Bell, R E; Boedo, J A; Bush, C E; Kaita, R; Kugel, H W; LeBlanc, B P; Mueller, D

    2008-08-04

    Steady-state handling of divertor heat flux is a critical issue for both ITER and spherical torus-based devices with compact high power density divertors. Significant reduction of heat flux to the divertor plate has been achieved simultaneously with favorable core and pedestal confinement and stability properties in a highly-shaped lower single null configuration in the National Spherical Torus Experiment (NSTX) [M. Ono et al., Nucl. Fusion 40, 557 2000] using high magnetic flux expansion at the divertor strike point and the radiative divertor technique. A partial detachment of the outer strike point was achieved with divertor deuterium injection leading to peak flux reduction from 4-6 MW m{sup -2} to 0.5-2 MW m{sup -2} in small-ELM 0.8-1.0 MA, 4-6 MW neutral beam injection-heated H-mode discharges. A self-consistent picture of outer strike point partial detachment was evident from divertor heat flux profiles and recombination, particle flux and neutral pressure measurements. Analytic scrape-off layer parallel transport models were used for interpretation of NSTX detachment experiments. The modeling showed that the observed peak heat flux reduction and detachment are possible with high radiated power and momentum loss fractions, achievable with divertor gas injection, and nearly impossible to achieve with main electron density, divertor neutral density or recombination increases alone.

  15. Geothermally heated Chamber of Commerce offices at Marlin, Texas. Final report

    SciTech Connect

    Not Available

    1981-07-31

    The use of an existing, low temperature, geothermal resource to heat the Chamber of Commerce offices in Marlin, Texas is described. A secondary purpose of the project is to attract new industries and businesses to Marlin via this alternate energy show-piece demonstration of a simple and practical application of Texas' low temperature geothermal resource.

  16. New Heat Flow Models in Fractured Geothermal Reservoirs - Final Report

    SciTech Connect

    Reis, John

    2001-03-31

    This study developed new analytical models for predicting the temperature distribution within a geothermal reservoir following reinjection of water having a temperature different from that of the reservoir. The study consisted of two parts: developing new analytical models for the heat conduction rate into multi-dimensional, parallelepiped matrix blocks and developing new analytical models for the advance of the thermal front through the geothermal reservoir. In the first part of the study, a number of semi-empirical models for the multi-dimensional heat conduction were developed to overcome the limitations to the exact solutions. The exact solution based on a similarity solution to the heat diffusion equation is the best model for the early-time period, but fails when thermal conduction fronts from opposing sides of the matrix block merge. The exact solution based on an infinite series solution was found not to be useful because it required tens of thousands of terms to be include d for accuracy. The best overall model for the entire conduction time was a semi-empirical model based on an exponential conduction rate. In the second part of the study, the early-time period exact solution based on similarity methods and the semi-empirical exponential model were used to develop new analytical models for the location of the thermal front within the reservoir during injection. These equations were based on an energy balance on the water in the fractured network. These convective models allowed for both dual and triple porosity reservoirs, i.e., one or two independent matrix domains. A method for incorporating measured fracture spacing distributions into these convective models was developed. It was found that there were only minor differences in the predicted areal extent of the heated zone between the dual and triple porosity models. Because of its simplicity, the dual porosity model is recommended. These new models can be used for preliminary reservoir studies

  17. Characterization of local heat fluxes around ICRF antennas on JET

    SciTech Connect

    Campergue, A.-L.; Jacquet, P.; Monakhov, I.; Arnoux, G.; Brix, M.; Sirinelli, A.; Milanesio, D.; Colas, L.; Collaboration: JET-EFDA Contributors

    2014-02-12

    When using Ion Cyclotron Range of Frequency (ICRF) heating, enhanced power deposition on Plasma-Facing Components (PFCs) close to the antennas can occur. Experiments have recently been carried out on JET with the new ITER-Like-Wall (ILW) to characterize the heat fluxes on the protection of the JET ICRF antennas, using Infra-Red (IR) thermography measurement. The measured heat flux patterns along the poloidal limiters surrounding powered antennas were compared to predictions from a simple RF sheath rectification model. The RF electric field, parallel to the static magnetic field in front of the antenna, was evaluated using the TOPICA code, integrating a 3D flattened model of the JET A2 antennas. The poloidal density variation in front of the limiters was obtained from the mapping of the Li-beam or edge reflectometry measurements using the flux surface geometry provided by EFIT equilibrium reconstruction. In many cases, this simple model can well explain the position of the maximum heat flux on the different protection limiters and the heat-flux magnitude, confirming that the parallel RF electric field and the electron plasma density in front of the antenna are the main driving parameters for ICRF-induced local heat fluxes.

  18. Anthropogenic heat flux estimation from space: first results

    NASA Astrophysics Data System (ADS)

    Chrysoulakis, Nektarios; Heldens, Wieke; Gastellu-Etchegorry, Jean-Philippe; Grimmond, Sue; Feigenwinter, Christian; Lindberg, Fredrik; Del Frate, Fabio; Klostermann, Judith; Mitraka, Zina; Esch, Thomas; Albitar, Ahmad; Gabey, Andrew; Parlow, Eberhard; Olofson, Frans

    2016-04-01

    While Earth Observation (EO) has made significant advances in the study of urban areas, there are several unanswered science and policy questions to which it could contribute. To this aim the recently launched Horizon 2020 project URBANFLUXES (URBan ANthrpogenic heat FLUX from Earth observation Satellites) investigates the potential of EO to retrieve anthropogenic heat flux, as a key component in the urban energy budget. The anthropogenic heat flux is the heat flux resulting from vehicular emissions, space heating and cooling of buildings, industrial processing and the metabolic heat release by people. Optical, thermal and SAR data from existing satellite sensors are used to improve the accuracy of the radiation balance spatial distribution calculation, using also in-situ reflectance measurements of urban materials are for calibration. EO-based methods are developed for estimating turbulent sensible and latent heat fluxes, as well as urban heat storage flux and anthropogenic heat flux spatial patterns at city scale and local scale by employing an energy budget closure approach. Independent methods and models are engaged to evaluate the derived products and statistical analyses provide uncertainty measures as well. Ultimate goal of the URBANFLUXES is to develop a highly automated method for estimating urban energy budget components to use with Copernicus Sentinel data, enabling its integration into applications and operational services. Thus, URBANFLUXES prepares the ground for further innovative exploitation of European space data in scientific activities (i.e. Earth system modelling and climate change studies in cities) and future and emerging applications (i.e. sustainable urban planning) by exploiting the improved data quality, coverage and revisit times of the Copernicus data. The URBANFLUXES products will therefore have the potential to support both sustainable planning strategies to improve the quality of life in cities, as well as Earth system models to

  19. Heat flux measurement in a high enthalpy plasma flow

    NASA Astrophysics Data System (ADS)

    Löhle, Stefan; Battaglia, Jean-Luc; Gardarein, Jean-Laurent; Jullien, Pierre; van Ootegem, Bruno

    2008-11-01

    It is a widely used approach to measure heat flux in harsh environments like high enthalpy plasma flows, fusion plasma and rocket motor combustion chambers based on solving the inverse heat conduction problem in a semi-infinite environment. This approach strongly depends on model parameters and geometrical aspects of the sensor design. In this work the surface heat flux is determined by solving the inverse heat conduction problem using an identified system as a direct model. The identification of the system is performed using calibration measurements with modern laser technique and advanced data handling. The results of the identified thermo-physical system show that a non-integer model appears most adapted to this particular problem. It is concluded that the new method improves the heat flux sensor significantly and furthermore extend its application to very short measurement times.

  20. Explosive Boiling at Very Low Heat Fluxes: A Microgravity Phenomenon

    NASA Technical Reports Server (NTRS)

    Hasan, M. M.; Lin, C. S.; Knoll, R. H.; Bentz, M. D.

    1993-01-01

    The paper presents experimental observations of explosive boiling from a large (relative to bubble sizes) flat heating surface at very low heat fluxes in microgravity. The explosive boiling is characterized as either a rapid growth of vapor mass over the entire heating surface due to the flashing of superheated liquid or a violent boiling spread following the appearance of single bubbles on the heating surface. Pool boiling data with saturated Freon 113 was obtained in the microgravity environment of the space shuttle. The unique features of the experimental results are the sustainability of high liquid superheat for long periods and the occurrence of explosive boiling at low heat fluxes (0.2 to 1.2 kW/sq m). For a heat flux of 1.0 kW/sq m a wall superheat of 17.9 degrees C was attained in ten minutes of heating. This was followed by an explosive boiling accompanied with a pressure spike and a violent bulk liquid motion. However, at this heat flux the vapor blanketing the heating surface could not be sustained. Stable nucleate boiling continued following the explosive boiling.

  1. Evaluating Importance of Heat Transport Mechanisms Neglected in Design of Low Temperature Geothermal Systems

    NASA Astrophysics Data System (ADS)

    Langevin, C. D.; Sukop, M. C.

    2009-12-01

    Design calculations for geothermal heating and cooling systems usually simplify or neglect many of the heat transport processes occurring in the subsurface. This is despite the fact that system efficiency, sustainability, and environmental impact all depend on heat transport in the subsurface. Design standards for the most popular systems, which use borehole heat exchangers, usually assume purely conductive heat transport in an infinite homogeneous domain. In reality, heat transport is affected by groundwater flow, buoyancy, thermal convection, temperature effects on viscosity, and possibly thermal dispersion and thermal non-equilibrium conditions between fluid and solid. Simulations using the SEAWAT computer program show the potential impact of these processes on the performance of ground energy systems. All simulations were based on a generic sand aquifer with 100 W/m borehole heat source/sink strength. Simulation results are in excellent agreement with the analytical solution for purely conductive heat transport from a vertical infinite line source. Adding thermal buoyancy effects to this simulation caused temperature to vary by more than 6 °C along a borehole that fully penetrated the 25-m thick aquifer. Fixing the temperature for the top boundary at the initial temperature value destabilized the density profile, leading to free thermal convection. Compared to the simulation including only buoyancy (and a no heat flux upper boundary), there was not as much temperature variation in the vertical direction, indicating that free thermal convection is an efficient mechanism for transporting heat. Including the effect of viscosity variations resulted in only a minor increase in flow velocity. Heat transport with regional groundwater flow driven by a head gradient was then represented with SEAWAT and compared with an analytical model. SEAWAT was used to simulate a hypothetical ground energy system with 64 wells spaced at a 10-m interval on a triangular mesh. When

  2. Surface Energy Heat Fluxes Using Remotely Sensed Parameters

    NASA Technical Reports Server (NTRS)

    Toll, David L.; Vukovich, Fred M.; Pontikes, Elizabeth G.

    1997-01-01

    Realistic estimates of surface energy heat fluxes are needed for the study of water and energy interactions between the land and atmosphere. The primary objective of this work is to study the estimation of surface heat energy fluxes using remote sensing derived parameters under different spatial and temporal conditions. Surface energy fluxes and remote sensing derived data from two sources were analyzed. First, we used surface heat flux, remote sensing, and ancillary data from the International Satellite Land Surface Climatology Project (ISLSCP), mapped at a 1 deg. x 1 deg. grid. Second, we used NOAA AVHRR (1 km), weather station, and ancillary data to derive estimates of surface latent and sensible heat energy fluxes over a 100 sq kilometers area for three test sites: 1) First ISLSCP Field Experiment (FIFE) grassland site, Konza Prairie, Kansas; 2) Howland, Maine Forest Ecosystem Dynamics Site; and 3) Walnut Gulch, scrubland site, surrounding Tombstone, Arizona. Satellite derived estimates of land surface temperature, surface albedo, and spectral vegetation index are used in selected models to provide estimates of surface heat fluxes. Analysis of results from the 1 deg. x 1 deg. grid for North America indicated there were similar, overall correlations between sensible and latent heat energy fluxes versus remotely sensed vegetation index and ground temperature during dry and wet year conditions. However, there were significant differences in correlations between years when stratified by land cover class. Analysis of 100 km x 100 km data (1 km resolution) indicated partitioning the areas in to primary versus secondary cover, with the secondary cover comprising less than 5% of the area, significantly improved surface heat energy flux estimates.

  3. Impact of flux distribution on elementary heating events

    NASA Astrophysics Data System (ADS)

    O'Hara, J. P.; De Moortel, I.

    2016-10-01

    Context. The complex magnetic field on the solar surface has been shown to contain a range of sizes and distributions of magnetic flux structures. The dynamic evolution of this magnetic carpet by photospheric flows provides a continual source of free magnetic energy into the solar atmosphere, which can subsequently be released by magnetic reconnection. Aims: We investigate how the distribution and number of magnetic flux sources impact the energy release and locations of heating through magnetic reconnection driven by slow footpoint motions. Methods: 3D magnetohydrodynamic (MHD) simulations using Lare3D are carried out, where flux tubes are formed between positive and negative sources placed symmetrically on the lower and upper boundaries of the domain, respectively. The flux tubes are subjected to rotational driving velocities on the boundaries and are forced to interact and reconnect. Results: Initially, simple flux distributions with two and four sources are compared. In both cases, central current concentrations are formed between the flux tubes and Ohmic heating occurs. The reconnection and subsequent energy release is delayed in the four-source case and is shown to produce more locations of heating, but with smaller magnitudes. Increasing the values of the background field between the flux tubes is shown to delay the onset of reconnection and increases the efficiency of heating in both the two- and four-source cases. The cases with two flux tubes are always more energetic than the corresponding four flux tube cases, however the addition of the background field makes this disparity less significant. A final experiment with a larger number of smaller flux sources is considered and the field evolution and energetics are shown to be remarkably similar to the two-source case, indicating the importance of the size and separation of the flux sources relative to the spatial scales of the velocity driver.

  4. Estimation of sensible heat, water vapor, and CO2 fluxes using the flux-variance method.

    PubMed

    Hsieh, Cheng-I; Lai, Mei-Chun; Hsia, Yue-Joe; Chang, Tsang-Jung

    2008-07-01

    This study investigated the flux-variance relationships of temperature, humidity, and CO(2), and examined the performance of using this method for predicting sensible heat (H), water vapor (LE), and CO(2) fluxes (F(CO2)) with eddy-covariance measured flux data at three different ecosystems: grassland, paddy rice field, and forest. The H and LE estimations were found to be in good agreement with the measurements over the three fields. The prediction accuracy of LE could be improved by around 15% if the predictions were obtained by the flux-variance method in conjunction with measured sensible heat fluxes. Moreover, the paddy rice field was found to be a special case where water vapor follows flux-variance relation better than heat does. However, the CO(2) flux predictions were found to vary from poor to fair among the three sites. This is attributed to the complicated CO(2) sources and sinks distribution. Our results also showed that heat and water vapor were transported with the same efficiency above the grassland and rice paddy. For the forest, heat was transported 20% more efficiently than evapotranspiration.

  5. Warren Estates-Manzanita Estates Reno, Nevada residential geothermal district heating system

    SciTech Connect

    McKay, F.; McKay, G.; McKay, S.; Flynn, T.

    1995-12-31

    Warren Estates-Manzanita Estates is the largest privately-owned and operated residential geothermal district heating system in the State of Nevada. The system has operated for ten years and presently services 95 homes. Geothermal energy is used to heat homes, domestic water, spas, swimming pools, and greenhouses. Four homes have installed driveway deicing systems using geothermal energy. This paper briefly describes the geothermal resource, wells, system engineering, operation, applications, and economics. The accompanying posters illustrate the geothermal area, system design, and various applications. The resource is part of the Moana geothermal field, located in southwest Reno. Excluding the Warren-Manzanita Estates, the well-known Moana field supports nearly 300 geothermal wells that supply fluids to individual residences, several motels, a garden nursery, a few churches, and a municipal swimming pool. The Warren-Manzanita Estates is ideally suited for residential district space heating because the resource is shallow, moderate-temperature, and chemically benign. The primary reservoir rock is the Kate Peak andesite, a Tertiary volcanic lahar that has excellent permeability within the narrow fault zones that bisect the property. The Kate Peak formation is overlain by impermeable Tertiary lake sediments and alluvium. Two production wells, each about 240 m deep, are completed near the center of the residential development at the intersection of two fault zones. Geothermal fluids are pumped at a rate of 15 to 25 l/s (260-400 gpm) from one of two wells at a temperature of 95{degrees}C (202{degrees}F) to two flat-plate heat exchangers. The heat exchangers transfer energy from the geothermal fluids to a second fluid, much like a binary geothermal power plant.

  6. High diversity of methanotrophic bacteria in geothermal soils affected by high methane fluxes

    NASA Astrophysics Data System (ADS)

    D'Alessandro, Walter; Gagliano, Antonina Lisa; Quatrini, Paola; Parello, Francesco

    2014-05-01

    Volcanic and geothermal systems emit endogenous gases by widespread degassing from soils, including CH4, a greenhouse gas 25 times as potent as CO2. Recently, it has been demonstrated that volcanic/geothermal soils act as source, but also as biological filter for methane release to the atmosphere. For long time, volcanic/geothermal soils has been considered inhospitable for methanotrophic microorganisms, but new extremophile methanotrophs belonging to Verrucomicrobia were identified in three different areas (Pozzuoli, Italy; Hell's Gate, New Zealand; Kamchatka, Russia), explaining anomalous behaviours in methane leakages of several geothermal/volcanic sites. Our aim was to increase the knowledge of the relationship between methane emissions from volcanic/geothermal areas and biological methane oxidation, by investigating a geothermal site of Pantelleria island (Italy). Pantelleria Island hosts a high enthalpy geothermal system characterized by high temperature, high CH4 and very low H2S fluxes. Such characteristics are reflected in potentially great supply of methane for methanotrophs and scarce presence of inhibitors of their activity (H2S and NH3) in the Pantelleria soils. Potential methanotrophic activity within these soils was already evidenced by the CH4/CO2 ratio of the flux measurements which was lower than that of the respective fumarolic manifestations indicating a loss of CH4 during the gas travel towards the earth's surface. In this study laboratory incubation experiments using soils sampled at Favara Grande, the main hydrothermal area of Pantelleria, showed very high methane consumption rates (up to 9500 ng CH4 h-1 g-1). Furthermore, microbiological and culture-independent molecular analyses allowed to detect the presence of methanotrophs affiliated to Gamma- and Alpha-Proteobacteria and to the newly discovered acidothermophilic methanotrophs Verrucomicrobia. Culturable methanotrophic Alpha-proteobacteria of the genus Methylocystis were isolated by

  7. Geothermal district-heating potential for casinos/hotels in Reno, Nevada

    SciTech Connect

    Not Available

    1981-11-30

    Results from the pre-feasibility study of a geothermal district heating system for greater Reno and the pre-feasibility study of providing geothermal heat to casinos/hotels located in downtown Reno by connection to the proposed district heating system (DHS) are combined. Geothermal sources were selected from published data. Potential users were selected from aerial and city planning maps, and published building and demographic information. Energy consumption data from the electric and gas utility was matched with consumption information from surveys of representative buildings by category and climatic data. As an example, a written survey was mailed to the casino/hotels and two on-site visits were made. Retrofit methodology and cost were examined for the casino/hotels and representative buildings. Based on the pre-feasibility studies, a geothermal district heating system for Reno appears technically and economically feasible. Furthermore, additional economic savings are achieved when the Reno casinos/hotels are connected to the DHS. Steamboat Hot Springs and a geothermal area east of downtown are the most promising geothermal sources for the DHS. The City of Reno has a large yearly heat load with an average heating degree days per year of 6022/sup 0/F days and a heating season greater than eight months.

  8. Heat Flow, Lower Crustal Thermochronology, and Transient Geotherms in the Mesozoic Southern African Continental Lithosphere

    NASA Astrophysics Data System (ADS)

    Schmitz, M. D.; Bell, D. R.; Bowring, S. A.

    2002-12-01

    There is a well-established debate regarding the role of higher mantle heat flux for accommodating the elevated average surface heat flow in the Proterozoic orogenic belts relative to the Archean cratonic regions of southern Africa1,2. Advocates of steeper off-craton lithospheric mantle thermal gradients commonly support their arguments with thermobarometric data indicating elevated temperatures at a given depth in off-craton versus cratonic mantle xenolith suites3,4, and together such inferences have cemented a paradigm of differential lithospheric thickness between Proterozoic orogenic belts (thin) and Archean cratons (thick). However, this inherently steady-state interpretation of lithospheric thermomechanical structure is at odds with emerging data pointing toward transient thermal perturbations and irreversible chemical modifications to the southern African lithosphere during the Late Mesozoic5,6. This contribution seeks to illustrate how an essentially "cratonic" thermal state in the Proterozoic lithospheric mantle of southern Africa remains compatible with nominally elevated surface heat flow in the same regions. Model geotherms have been constructed utilizing published surface heat flow, heat production and thermal conductivity measurements1, and seismically-derived crustal thickness estimates7. New heat-producing element concentration data for kimberlite-borne high-pressure granulite xenoliths from the Proterozoic domains constrain lower crustal heat production to be in the range of 0.15 to 0.2 μW/m3. A family of geologically realistic crustal heat production models accommodates surface heat flow >50 mW/m2, while maintaining moderate basal mantle heat flux <15 mW/m2, with associated lithospheric mantle geotherms and thickness indistinguishable from those of cratonic mantle. This family of models is further consistent with constraints on pre-Mesozoic lower crustal paleotemperatures of <450°C imposed by rutile U-Pb thermochronology in the craton

  9. Turbulent Heat Fluxes in the Atmosphere of Venus

    NASA Astrophysics Data System (ADS)

    Izakov, M. N.

    2002-05-01

    A thermal regime of the troposphere of Venus is mainly determined by the greenhouse effect. A closeness of the real temperature gradient to the adiabatic one indicates that turbulent heat fluxes are also essential. Additional problems arise as only about 11% of the solar radiation absorbed by the planet reaches the surface, and most of it is taken up in the clouds at altitudes of 60-70 km. The present study summarizes experimental data on atmospheric parameters related to turbulence and estimates turbulent fluxes and turbulence characteristics. These data confirm the author's hypothesis of an anomalous downward turbulent heat flux in the free atmosphere. A normal upward turbulent heat flux exists in the planetary boundary layer.

  10. Utilization of geothermal heat in tropical fruit-drying process

    SciTech Connect

    Chen, B.H.; Lopez, L.P.; King, R.; Fujii, J.; Tanaka, M.

    1982-10-01

    The power plant utilizes only the steam portion of the HGP-A well production. There are approximately 50,000 pounds per hour of 360/sup 0/F water produced (approximately 10 million Btu per hour) and the water is currently not used and is considered a waste. This tremendous resource could very well be used in applications such as food processing, food dehydration and other industrial processing that requires low-grade heat. One of the applications is examined, namely the drying of tropical fruits particularly the papaya. The papaya was chosen for the obvious reason that it is the biggest crop of all fruits produced on the Big Island. A conceptual design of a pilot plant facility capable of processing 1000 pounds of raw papaya per day is included. This facility is designed to provide a geothermally heated dryer to dehydrate papayas or other tropical fruits available on an experimental basis to obtain data such as drying time, optimum drying temperature, etc.

  11. Feasibility analysis of geothermal district heating for Lakeview, Oregon

    SciTech Connect

    Not Available

    1980-12-23

    An analysis of the geothermal resource at Lakeview, Oregon, indicates that a substantial resource exists in the area capable of supporting extensive residential, commercial and industrial heat loads. Good resource productivity is expected with water temperatures of 200{degrees}F at depths of 600 to 3000 feet in the immediate vicinity of the town. Preliminary district heating system designs were developed for a Base Case serving 1170 homes, 119 commercial and municipal buildings, and a new alcohol fuel production facility; a second design was prepared for a downtown Mini-district case with 50 commercial users and the alcohol plant. Capital and operating costs were determined for both cases. Initial development of the Lakeview system has involved conducting user surveys, well tests, determinations of institutional requirements, system designs, and project feasibility analyses. A preferred approach for development will be to establish the downtown Mini-district and, as experience and acceptance are obtained, to expand the system to other areas of town. Projected energy costs for the Mini-district are $10.30 per million Btu while those for the larger Base Case design are $8.20 per million Btu. These costs are competitive with costs for existing sources of energy in the Lakeview area.

  12. Systems study of drilling for installation of geothermal heat pumps

    SciTech Connect

    Finger, J.T.; Sullivan, W.N.; Jacobson, R.D.; Pierce, K.G.

    1997-09-01

    Geothermal, or ground-source, heat pumps (GHP) are much more efficient than air-source units such as conventional air conditioners. A major obstacle to their use is the relatively high initial cost of installing the heat-exchange loops into the ground. In an effort to identify drivers which influence installation cost, a number of site visits were made during 1996 to assess the state-of-the-art in drilling for GHP loop installation. As an aid to quantifying the effect of various drilling-process improvements, we constructed a spread-sheet based on estimated time and material costs for all the activities required in a typical loop-field installation. By substituting different (improved) values into specific activity costs, the effect on total project costs can be easily seen. This report contains brief descriptions of the site visits, key points learned during the visits, copies of the spread-sheet, recommendations for further work, and sample results from sensitivity analysis using the spread-sheet.

  13. Development of the Geothermal Heat Pump Market in China; Renewable Energy in China

    SciTech Connect

    Not Available

    2006-03-01

    This case study is one in a series of Success Stories on developing renewable energy technologies in China for a business audience. It focuses on the development of the geothermal heat pump market in China.

  14. Numerical Analysis of a Radiant Heat Flux Calibration System

    NASA Technical Reports Server (NTRS)

    Jiang, Shanjuan; Horn, Thomas J.; Dhir, V. K.

    1998-01-01

    A radiant heat flux gage calibration system exists in the Flight Loads Laboratory at NASA's Dryden Flight Research Center. This calibration system must be well understood if the heat flux gages calibrated in it are to provide useful data during radiant heating ground tests or flight tests of high speed aerospace vehicles. A part of the calibration system characterization process is to develop a numerical model of the flat plate heater element and heat flux gage, which will help identify errors due to convection, heater element erosion, and other factors. A 2-dimensional mathematical model of the gage-plate system has been developed to simulate the combined problem involving convection, radiation and mass loss by chemical reaction. A fourth order finite difference scheme is used to solve the steady state governing equations and determine the temperature distribution in the gage and plate, incident heat flux on the gage face, and flat plate erosion. Initial gage heat flux predictions from the model are found to be within 17% of experimental results.

  15. High heat flux measurements and experimental calibrations/characterizations

    NASA Technical Reports Server (NTRS)

    Kidd, Carl T.

    1992-01-01

    Recent progress in techniques employed in the measurement of very high heat-transfer rates in reentry-type facilities at the Arnold Engineering Development Center (AEDC) is described. These advances include thermal analyses applied to transducer concepts used to make these measurements; improved heat-flux sensor fabrication methods, equipment, and procedures for determining the experimental time response of individual sensors; performance of absolute heat-flux calibrations at levels above 2,000 Btu/cu ft-sec (2.27 kW/cu cm); and innovative methods of performing in-situ run-to-run characterizations of heat-flux probes installed in the test facility. Graphical illustrations of the results of extensive thermal analyses of the null-point calorimeter and coaxial surface thermocouple concepts with application to measurements in aerothermal test environments are presented. Results of time response experiments and absolute calibrations of null-point calorimeters and coaxial thermocouples performed in the laboratory at intermediate to high heat-flux levels are shown. Typical AEDC high-enthalpy arc heater heat-flux data recently obtained with a Calspan-fabricated null-point probe model are included.

  16. QUANTIFICATION OF HEAT FLUX FROM A REACTING THERMITE SPRAY

    SciTech Connect

    Eric Nixon; Michelle Pantoya

    2009-07-01

    Characterizing the combustion behaviors of energetic materials requires diagnostic tools that are often not readily or commercially available. For example, a jet of thermite spray provides a high temperature and pressure reaction that can also be highly corrosive and promote undesirable conditions for the survivability of any sensor. Developing a diagnostic to quantify heat flux from a thermite spray is the objective of this study. Quick response sensors such as thin film heat flux sensors can not survive the harsh conditions of the spray, but more rugged sensors lack the response time for the resolution desired. A sensor that will allow for adequate response time while surviving the entire test duration was constructed. The sensor outputs interior temperatures of the probes at known locations and utilizes an inverse heat conduction code to calculate heat flux values. The details of this device are discussed and illustrated. Temperature and heat flux measurements of various thermite spray conditions are reported. Results indicate that this newly developed energetic material heat flux sensor provides quantitative data with good repeatability.

  17. Heat flux and precipitation estimates from oceanographic observations.

    PubMed

    Ostapoff, F; Tarbeyev, Y; Worthem, S

    1973-06-01

    Surface meteorological observations and salinity and temperature profiles were made in the intertropical convergence zone during July 1972. Over an 18-hour period, estimates of the heat budget in the top layer of the ocean and estimates of the total heat flux made by using aerodynamic parameterization equations balance within 10 percent. The salinity budget provides a precipitation estimate. Due to the stable stratification established by the salinity dilution in the wave-mixed layer by rain, the total heat flux to the atmosphere is being extracted from this shallow layer. As a result, large sea surface temperature drops occur regionally and may be capable of inhibiting atmospheric convection. PMID:17735928

  18. Horizontally integrated atmospheric heat flux from an Arctic lead

    NASA Astrophysics Data System (ADS)

    Glendening, John W.

    1995-03-01

    Vertical distribution of the horizontally integrated heat injected into the atmosphere by an Arctic lead is investigated, based upon large-eddy simulations of its convective plume. The horizontally integrated heat flux varies exponentially with height except under conditions of relatively weak cross flow, when vertical advective transport becomes significant. Its vertical scale, which depends upon the lead size, surface heat flux, atmospheric stratification, and cross-lead wind component, is approximately one fourth of the maximum plume height, indicating that the depth of largest heat transfer is significantly shallower than the depth of the plume. A parameterization is developed to incorporate this small-scale heat injection into large-scale models which cannot resolve individual leads. The amount of heat recaptured by the ice downwind of a lead is significant when cross-lead flow is relatively strong and when the plume depth is shallow.

  19. Urban heat islands in the subsurface as sustainable source for geothermal energy

    NASA Astrophysics Data System (ADS)

    Menberg, Kathrin; Bayer, Peter; Blum, Philipp

    2014-05-01

    The urban heat island (UHI) is not a phenomenon that solely occurs in the atmosphere with increased air temperatures. We also observe it in the subsurface, and groundwater temperatures in shallow aquifers are strongly influenced by anthropogenic land surface alterations. Widespread thermal anomalies, which are triggered by various processes, such as increased ground surface temperatures (GST) and heat loss from buildings, can be found under many urban areas. With groundwater temperatures elevated by several degrees these aquifers represent large amounts of stored thermal energy. However, to exploit these attractive geothermal reservoirs efficiently and sustainably, the processes, which lead to the profound subsurface urban warming, need to be identified and quantified. In the current study, the spatial extension of the heat anomalies beneath several German cities, such as Berlin, Munich, Karlsruhe and Cologne, is scrutinized by mapping groundwater temperatures in a dense network of observation wells. With the high-resolved spatial distribution of groundwater temperatures, the dominant heat sources and important driving factors can be identified and incorporated into an analytical heat flux model. The annual anthropogenic heat input into the aquifer originating from several heat sources, such as increased GST, basements, sewage networks, district heating networks and reinjections of thermal waste water, is estimated by a Monte Carlo simulation for the cities of Cologne and Karlsruhe. All studied cities exhibit aquifers with significantly elevated temperatures, with the highest temperatures of up to 18°C prevailing in the densely built-up city centers. But also in suburban and industrial areas groundwater temperatures are several degrees above the rural background. The accumulated heat content in the urban aquifers can be estimated based on the thermal ground properties. This content is compared to the annual space heating demand in order to analyze the space

  20. Turbine blade and vane heat flux sensor development, phase 1

    NASA Astrophysics Data System (ADS)

    Atkinson, W. H.; Cyr, M. A.; Strange, R. R.

    1984-08-01

    Heat flux sensors available for installation in the hot section airfoils of advanced aircraft gas turbine engines were developed. Two heat flux sensors were designed, fabricated, calibrated, and tested. Measurement techniques are compared in an atmospheric pressure combustor rig test. Sensors, embedded thermocouple and the Gordon gauge, were fabricated that met the geometric and fabricability requirements and could withstand the hot section environmental conditions. Calibration data indicate that these sensors yielded repeatable results and have the potential to meet the accuracy goal of measuring local heat flux to within 5%. Thermal cycle tests and thermal soak tests indicated that the sensors are capable of surviving extended periods of exposure to the environment conditions in the turbine. Problems in calibration of the sensors caused by severe non-one dimensional heat flow were encountered. Modifications to the calibration techniques are needed to minimize this problem and proof testing of the sensors in an engine is needed to verify the designs.

  1. Turbine blade and vane heat flux sensor development, phase 2

    NASA Technical Reports Server (NTRS)

    Atkinson, W. H.; Cyr, M. A.; Strange, R. R.

    1985-01-01

    The development of heat flux sensors for gas turbine blades and vanes and the demonstration of heat transfer measurement methods are reported. The performance of the heat flux sensors was evaluated in a cylinder in cross flow experiment and compared with two other heat flux measurement methods, the slug calorimeter and a dynamic method based on fluctuating gas and surface temperature. Two cylinders, each instrumented with an embedded thermocouple sensor, a Gardon gauge, and a slug calorimeter, were fabricated. Each sensor type was calibrated using a quartz lamp bank facility. The instrumented cylinders were then tested in an atmospheric pressure combustor rig at conditions up to gas stream temperatures of 1700K and velocities to Mach 0.74. The test data are compared to other measurements and analytical prediction.

  2. Turbine blade and vane heat flux sensor development, phase 1

    NASA Technical Reports Server (NTRS)

    Atkinson, W. H.; Cyr, M. A.; Strange, R. R.

    1984-01-01

    Heat flux sensors available for installation in the hot section airfoils of advanced aircraft gas turbine engines were developed. Two heat flux sensors were designed, fabricated, calibrated, and tested. Measurement techniques are compared in an atmospheric pressure combustor rig test. Sensors, embedded thermocouple and the Gordon gauge, were fabricated that met the geometric and fabricability requirements and could withstand the hot section environmental conditions. Calibration data indicate that these sensors yielded repeatable results and have the potential to meet the accuracy goal of measuring local heat flux to within 5%. Thermal cycle tests and thermal soak tests indicated that the sensors are capable of surviving extended periods of exposure to the environment conditions in the turbine. Problems in calibration of the sensors caused by severe non-one dimensional heat flow were encountered. Modifications to the calibration techniques are needed to minimize this problem and proof testing of the sensors in an engine is needed to verify the designs.

  3. Geothermal direct-heat utilization assistance: Federal assistance program. Quarterly project progress report, October--December 1995

    SciTech Connect

    1996-02-01

    The report summarizes geothermal technical assistance, R&D and technology transfer activities of the Geo-Heat Center at Oregon Institute of Technology for the first quarter of FY-96. It describes 90 contacts with parties during this period related to technical assistance with geothermal direct heat projects. Areas dealt with include geothermal heat pumps, space heating, greenhouses, aquaculture, equipment and resources. Research activities are summarized on low-temperature resource assessment, geothermal district heating system cost evaluation and silica waste utilization project. Outreach activities include the publication of a geothermal direct use Bulletin, dissemination of information, geothermal library, technical papers and seminars, development of a webpage, and progress monitor reports on geothermal resources and utilization.

  4. Model sensitivity of ice flux over the grounding line to present-day climatic forcing and geothermal flux

    NASA Astrophysics Data System (ADS)

    Kleiner, Thomas; Humbert, Angelika

    2016-04-01

    Large uncertainties remain in the current and future contribution to sea level change from Antarctica from observations and numerical flow modelling. Within the SeaRISE project atmospheric, oceanic, and subglacial forcing scenarios were applied to different ice-sheet models to assess Antarctic ice sheet sensitivity over a 500 year timescale. The scenario results have been compared to the individual state of each model at the end of its spin-up. It has been shown, that the model results highly depend on the chosen climate forcing and spin-up strategy. Here we use the Parallel Ice Sheet Model (PISM) to perform spin-up simulations across different data sets for present-day boundary conditions for the Antarctic Ice Sheet (surface temperature, surface mass balance and geothermal flux). The utilized spin-up methods include free evolving and geometry constrained simulations. Here we present our analysis of the ice flux over the grounding line for each set-up and compare the fluxes from large drainage basin units with estimates derived from remote sensing.

  5. Corrections of Heat Flux Measurements on Launch Vehicles

    NASA Technical Reports Server (NTRS)

    Reinarts, Thomas R.; Matson, Monique L.; Walls, Laurie K.

    2002-01-01

    Knowledge of aerothermally induced convective heat transfer is important in the design of thermal protection systems for launch vehicles. Aerothermal models are typically calibrated via the data from circular, in-flight, flush-mounted surface heat flux gauges exposed to the thermal and velocity boundary layers of the external flow. Typically, copper or aluminum Schmidt- Boelter gauges, which take advantage of the one-dimensional Fourier's law of heat conduction, are used to measure the incident heat flux. This instrumentation, when surrounded by low-conductivity insulation, has a wall temperature significantly lower than the insulation. As a result of this substantial disturbance to the thermal boundary layer, the heat flux incident on the gauge tends to be considerably higher than it would have been on the insulation had the calorimeter not been there. In addition, radial conductive heat transfer from the hotter insulation can cause the calorimeter to indicate heat fluxes higher than actual. An overview of an effort to develop and calibrate gauge correction techniques for both of these effects will be presented.

  6. Nonlinear aspects of high heat flux nucleate boiling heat transfer. Part 1, Formulation

    SciTech Connect

    Sadasivan, P.; Unal, C.; Nelson, R.

    1994-04-01

    This paper outlines the essential details of the formulation and numerical implementation of a model used to study nonlinear aspects of the macrolayer-controlled heat transfer process associated with high heat flux nucleate boiling and the critical heat flux. The model addresses the three-dimensional transient conduction heat transfer process within the problem domain comprised of the macrolayer and heater. Heat dissipation from the heater is modeled as the sum of transient transport into the macrolayer, and the heat loss resulting from evaporation of menisci associated with vapor stems.

  7. Downstream Heat Flux Profile vs. Midplane T Profile in Tokamaks

    SciTech Connect

    Robert J. Goldston

    2009-08-20

    The relationship between the midplane scrape-off-layer electron temperature profile and the parallel heat flux profile at the divertor in tokamaks is investigated. A model is applied which takes into account anisotropic thermal diffusion, in a rectilinear geometry with constant density. Eigenmode analysis is applied to the simplified problem with constant thermal diffusivities. A self-similar nonlinear solution is found for the more realistic problem with anisotropically temperature-dependent thermal diffusivities. Numerical solutions are developed for both cases, with spatially dependent heat flux emerging from the plasma. For both constant and temperature-dependent thermal diffusivities it is found that, below about one-half of its peak, the heat flux profile shape at the divertor, compared with the midplane temperature profile shape, is robustly described by the simplest two-point model. However the physical processes are not those assumed in the simplest two-point model, nor is the numerical coefficient relating q||div to Tmp χ||mp/L|| as predicted. For realistic parameters the peak in the heat flux, moreover, can be reduced by a factor of two or more from the two-point model scaling which fits the remaining profile. For temperature profiles in the SOL region above the x-point set by marginal stability, the heat flux profile to the divertor can be largely decoupled from the prediction of the two-point model. These results suggest caveats for data interpretation, and possibly favorable outcomes for divertor configurations with extended field lines.

  8. Geothermal Energy.

    ERIC Educational Resources Information Center

    Conservation and Renewable Energy Inquiry and Referral Service (DOE), Silver Spring, MD.

    An introduction to geothermal energy is provided in this discussion of: (1) how a geothermal reservoir works; (2) how to find geothermal energy; (3) where it is located; (4) electric power generation using geothermal energy; (5) use of geothermal energy as a direct source of heat; (6) geopressured reservoirs; (7) environmental effects; (8)…

  9. Mass, heat and freshwater fluxes in the South Indian Ocean

    NASA Technical Reports Server (NTRS)

    Fu, Lee-Lueng

    1986-01-01

    Six hydrographic sections were used to examine the circulation and property fluxes in the South Indian Ocean from 10 to 32 deg S. The calculations were made by applying an inverse method to the data. In the interior of the South Indian Ocean, the geostrophic flow is generally northward. At 18 deg S, the northward interior mass flux is balanced by the southward Ekman mass flux at the surface, whereas at 32 deg S the northward interior mass flux is balanced by the southward mass flux of the Agulhas Current. There is a weak, southward mass flux of 6 x 10 to the 9th kg/s in the Mozambique Channel. The rate of water exchange between the Pacific Ocean and the Indian Ocean is dependent on the choice of the initial reference level used in the inverse calculation. The choice of 1500 m, the depth of the deep oxygen minimum, has led to a flux of water from the Pacific Ocean to the Indian Ocean at a rate of 6.6 x 10 to the 9th kg/s. Heat flux calculations indicate that the Indian Ocean is exporting heat to the rest of the world's oceans at a rate of -0.69 x 10 to the 15th W at 18 deg S and -0.25 x 10 to the 15th W at 32 deg S (negative values being southward).

  10. High heat flux experiments of saddle type divertor module

    NASA Astrophysics Data System (ADS)

    Suzuki, Satoshi; Akiba, Masato; Araki, Masanori; Satoh, Kazuyoshi; Yokoyama, Kenji; Dairaku, Masayuki

    1994-09-01

    JAERI has been extensively developing plasma facing components for next tokomak devices. The authors have developed a saddle type divertor module which consists of saddle-shaped armor tiles brazed on metal heat sink. This paper presents the experimental and analytical results of thermal cycling experiments of the saddle type divertor module. The divertor module has unidirectional CFC armor tiles brazed on OFHC copper heat sink. A twisted tape was inserted in the cooling tube to enhance the heat transfer. In the experiments, thermal response of the divertor module was monitored by an infrared camera and thermocouples. The maximum incident heat flux was 24.5 MW/m 2 for a duration of 30 s. No degradation of thermal response was observed during the experiment. As a result, the saddle type divertor module successfully endured at an incident heat flux of over 20 MW/m 2 under steady state conditions for 1000 cycles.

  11. Monitoring of Building Heating and Cooling Systems Based on Geothermal Heat Pump in Galicia (Spain)

    NASA Astrophysics Data System (ADS)

    Iglesias, M.; Rodriguez, J.; Franco, D.

    2012-10-01

    In November 2009 was signed an agreement between Galicia's Government and EnergyLab to develop a project related with the geothermal heatpumps (hereafter, GSHP) technology. That project consisted in replacing the existing thermal equipment generators (diesel boilers and air-water heat pumps) by GSHP systems in representative public buildings: two nursery schools, a university library, a health centre and a residential building. This new systems will reach the demands of existing heating, cooling and domestic hot water (hereafter, DHW). These buildings can serve as examples of energy and economic savings that can offer this technology. We will show detailed analysis of the GSHP facilities monitored, since the starting-up of them. Which includes: COP's, EER's, energy consumption, operating costs, operation hours of the system, economic and emissions comparative, geothermal exchange evolution graphs, environmental conditions evolution graphs (temperature and demands), etc. The results presented show an example of the important benefits of the GSHP technology and the significant savings that can offer its implementation for heating, cooling and DHW production. Note to the reader: The article number has been corrected on web pages on November 22, 2013.

  12. Numerical investigation of one-dimensional heat-flux calculations

    NASA Astrophysics Data System (ADS)

    Boyd, C. F.; Howell, A.

    1994-10-01

    New computer codes to determine the heat transfer rate from wind tunnel model surface temperature measurements have been developed for use in the Navy's Hypervelocity Wind Tunnel No. 9 (Tunnel 9). The existing code, which assumes one-dimensional (1D) conduction in a Cartesian coordinate system, accurately predicts 1D heat-flux when applied to flat or nearly flat geometries. Heating rates are overpredicted when the code is applied to cylindrical, spherical, and conical geometries. The over-prediction increases with larger test times and smaller radius of curvature. Heating rates are also over-predicted when the code is applied under a two-dimensional (2D) heating load that varies linearly in space. This over-prediction increases with larger test times and larger spatial gradient of heat-flux but is small for typical Tunnel 9 applications. Two new computer codes, which assume 1D conduction in cylindrical and spherical coordinates, accurately predict 1D heat-flux applied to cylindrical, spherical, and conical geometries. These two codes are online for use as a tool in evaluating heat transfer from Tunnel 9 data.

  13. Geothermal district heating and cooling of hotel/casinos in downtown Reno, Nevada

    SciTech Connect

    Cerci, Y.; Kanoglu, M.; Cengel, Y.A.; Turner, R.H.

    1996-12-31

    In this paper, potential revenues from the proposed geothermal district heating/cooling system for the hotel/casino complexes in downtown Reno, Nevada are estimated by analyzing their actual electricity and natural gas bills during 1993 through 1994. The geothermal system appears to be feasible, and financially very attractive. The geothermal district system can meet the entire heating and cooling requirements of the hotel/casinos, generating total potential revenues of $3,486,000 per year. Also, other buildings around the downtown area such as Saint Mary`s Hospital, several motels, business complexes, Washoe County School District Building, and even the UNR campus will add extra potential revenues, if these buildings are connected to the geothermal grid. Since most buildings around the downtown use central heating and cooling system, the retrofit costs for the both system should be minimal.

  14. Geothermal direct-heat utilization assistance. Quarterly project progress report, January--March 1994

    SciTech Connect

    Not Available

    1994-05-01

    The Geo-Heat Center provides technical assistance on geothermal direct heat applications to developers, consultants and the public which could include: data and information on low-temperature (< 1500 C) resources, space and district heating, geothermal heat pumps, greenhouses, aquaculture, industrial processes and other technologies. This assistance could include preliminary engineering feasibility studies, review of direct-use project plans, assistance in project material and equipment selection, analysis and solutions of project operating problems, and information on resources and utilization. The following are brief descriptions of technical assistance provided during the second quarter of the program.

  15. Geothermal direct-heat utilization assistance. Quarterly project progress report, October--December 1993

    SciTech Connect

    Not Available

    1993-12-31

    This report consists of brief summaries of the activities of the Geo-Heat Center during the report period. Technical assistance was given to requests from 20 states in the following applications: space and district heating; geothermal heat pumps; greenhouses; aquaculture; industrial plants; electric power; resource/well; equipment; and resort/spa. Research and development activities progressed on (1) compilation of data on low-temperature resources and (2) evaluation of groundwater vs. ground-coupled heat pumps. Also summarized are technology transfer activities and geothermal progress monitoring activities.

  16. Flow-excursion-induced dryout at low-heat-flux

    SciTech Connect

    Khatib-Rahbar, M.; Cazzoli, E.G.

    1983-01-01

    Flow-excursion-induced dryout at low-heat-flux natural-convection boiling, typical of liquid-metal fast-breeder reactors, is addressed. Steady-state calculations indicate that low-quality boiling is possible up to the point of Ledinegg instability leading to flow excursion and subsequent dryout in agreement with experimental data. A flow-regime-dependent dryout heat flux relationship based upon saturated boiling criterion is also presented. Transient analysis indicates that premature flow excursion can not be ruled out and sodium boiling is highly transient dependent. Analysis of a high-heat-flux forced convection, loss-of-flow transient shows a significantly faster flow excursion leading to dryout in excellent agreement with parallel calculations using the two-dimensional THORAX code. 17 figures.

  17. Remote high-temperature insulatorless heat-flux gauge

    DOEpatents

    Noel, Bruce W.

    1993-01-01

    A remote optical heat-flux gauge for use in extremely high temperature environments is described. This application is possible because of the use of thermographic phosphors as the sensing media, and the omission of the need for an intervening layer of insulator between phosphor layers. The gauge has no electrical leads, but is interrogated with ultraviolet or laser light. The luminescence emitted by the two phosphor layers, which is indicative of the temperature of the layers, is collected and analyzed in order to determine the heat flux incident on the surface being investigated. The two layers of thermographic phosphor must be of different materials to assure that the spectral lines collected will be distinguishable. Spatial heat-flux measurements can be made by scanning the light across the surface of the gauge.

  18. Remote high-temperature insulatorless heat-flux gauge

    DOEpatents

    Noel, B.W.

    1993-12-28

    A remote optical heat-flux gauge for use in extremely high temperature environments is described. This application is possible because of the use of thermographic phosphors as the sensing media, and the omission of the need for an intervening layer of insulator between phosphor layers. The gauge has no electrical leads, but is interrogated with ultraviolet or laser light. The luminescence emitted by the two phosphor layers, which is indicative of the temperature of the layers, is collected and analyzed in order to determine the heat flux incident on the surface being investigated. The two layers of thermographic phosphor must be of different materials to assure that the spectral lines collected will be distinguishable. Spatial heat-flux measurements can be made by scanning the light across the surface of the gauge. 3 figures.

  19. Direct utilization of geothermal energy for space and water heating at Marlin, Texas. Final report

    SciTech Connect

    Conover, M.F.; Green, T.F.; Keeney, R.C.; Ellis, P.F. II; Davis, R.J.; Wallace, R.C.; Blood, F.B.

    1983-05-01

    The Torbett-Hutchings-Smith Memorial Hospital geothermal heating project, which is one of nineteen direct-use geothermal projects funded principally by DOE, is documented. The five-year project encompassed a broad range of technical, institutional, and economic activities including: resource and environmental assessments; well drilling and completion; system design, construction, and monitoring; economic analyses; public awareness programs; materials testing; and environmental monitoring. Some of the project conclusions are that: (1) the 155/sup 0/F Central Texas geothermal resource can support additional geothermal development; (2) private-sector economic incentives currently exist, especially for profit-making organizations, to develop and use this geothermal resource; (3) potential uses for this geothermal resource include water and space heating, poultry dressing, natural cheese making, fruit and vegetable dehydrating, soft-drink bottling, synthetic-rubber manufacturing, and furniture manufacturing; (4) high maintenance costs arising from the geofluid's scaling and corrosion tendencies can be avoided through proper analysis and design; (5) a production system which uses a variable-frequency drive system to control production rate is an attractive means of conserving parasitic pumping power, controlling production rate to match heating demand, conserving the geothermal resource, and minimizing environmental impacts.

  20. Lightning dock geothermal space heating project, Lightning Dock KGRA, New Mexico. Final report

    SciTech Connect

    McCants, T.W.

    1980-12-01

    The proposed project was to take the existing geothermal greenhouse and home heating systems, which consisted of pumping geothermal water and steam through passive steam heaters, and convert the systems to one using modern heat exchange units. It was proposed to complete the existing unfinished, re-inforced glass side wall, wood framed structure, as a nursery lath house, the purpose of which would be to use geothermal water in implementing university concepts on the advantages of bottom heat to establish hardy root systems in nursery and bedding plants. The use of this framework was abandoned in favor of erecting new structures for the proposed purpose. The final project of the proposal was the establishment of a drip irrigation system, to an area just west of the existing greenhouse and within feet of the geothermal well. Through this drip irrigation system geothermal water would be pumped, to prevent killing spring frosts. The purpose of this area of the proposal is to increase the potential use of existing geothermal waters of the Lightning Dock KGRA, in opening a new geothermal agri-industry which is economically feasible for the area and would be extremely energy efficient.

  1. Long-term evolution of anthropogenic heat fluxes into a subsurface urban heat island.

    PubMed

    Menberg, Kathrin; Blum, Philipp; Schaffitel, Axel; Bayer, Peter

    2013-09-01

    Anthropogenic alterations in urban areas influence the thermal environment causing elevated atmospheric and subsurface temperatures. The subsurface urban heat island effect is observed in several cities. Often shallow urban aquifers exist with thermal anomalies that spread laterally and vertically, resulting in the long-term accumulation of heat. In this study, we develop an analytical heat flux model to investigate possible drivers such as increased ground surface temperatures (GSTs) at artificial surfaces and heat losses from basements of buildings, sewage systems, subsurface district heating networks, and reinjection of thermal wastewater. By modeling the anthropogenic heat flux into the subsurface of the city of Karlsruhe, Germany, in 1977 and 2011, we evaluate long-term trends in the heat flux processes. It revealed that elevated GST and heat loss from basements are dominant factors in the heat anomalies. The average total urban heat flux into the shallow aquifer in Karlsruhe was found to be ∼759 ± 89 mW/m(2) in 1977 and 828 ± 143 mW/m(2) in 2011, which represents an annual energy gain of around 1.0 × 10(15) J. However, the amount of thermal energy originating from the individual heat flux processes has changed significantly over the past three decades.

  2. The Impact of Geothermal Heat on the Scandinavian Ice Sheet's LGM Extent

    NASA Astrophysics Data System (ADS)

    Szuman, Izabela; Ewertowski, Marek W.; Kalita, Jakub Z.

    2016-04-01

    The last Scandinavian ice sheet attained its most southern extent over Poland and Germany, protruding c. 200 km south of the main ice sheet mass. There are number of factors that may control ice sheet dynamics and extent. One of the less recognised is geothermal heat, which is heat that is supplied to the base of the ice sheet. A heat at the ice/bed interface plays a crucial role in controlling ice sheet stability, as well as impacting basal temperatures, melting, and ice flow velocities. However, the influence of geothermal heat is still virtually neglected in reconstructions and modelling of paleo-ice sheets behaviour. Only in a few papers is geothermal heat recalled though often in the context of past climatic conditions. Thus, the major question is if and how spatial differences in geothermal heat had influenced paleo-ice sheet dynamics and in consequence their extent. Here, we assumed that the configuration of the ice sheet along its southern margin was moderately to strongly correlated with geothermal heat for Poland and non or negatively correlated for Germany.

  3. Distributed Sensible Heat Flux Measurements for Wireless Sensor Networks

    NASA Astrophysics Data System (ADS)

    Huwald, H.; Brauchli, T.; Lehning, M.; Higgins, C. W.

    2015-12-01

    The sensible heat flux component of the surface energy balance is typically computed using eddy covariance or two point profile measurements while alternative approaches such as the flux variance method based on convective scaling has been much less explored and applied. Flux variance (FV) certainly has a few limitations and constraints but may be an interesting and competitive method in low-cost and power limited wireless sensor networks (WSN) with the advantage of providing spatio-temporal sensible heat flux over the domain of the network. In a first step, parameters such as sampling frequency, sensor response time, and averaging interval are investigated. Then we explore the applicability and the potential of the FV method for use in WSN in a field experiment. Low-cost sensor systems are tested and compared against reference instruments (3D sonic anemometers) to evaluate the performance and limitations of the sensors as well as the method with respect to the standard calculations. Comparison experiments were carried out at several sites to gauge the flux measurements over different surface types (gravel, grass, water) from the low-cost systems. This study should also serve as an example of spatially distributed sensible heat flux measurements.

  4. Using electrical conductivity to monitor geothermal solute flux in major rivers of Yellowstone National Park

    NASA Astrophysics Data System (ADS)

    McCleskey, R. B.; Mahony, D.; Lowenstern, J. B.; Heasler, H.; Nordstrom, D. K.

    2014-12-01

    Thermal output from the magma chamber underlying Yellowstone National Park (YNP) can be estimated by monitoring Cl flux in major rivers draining the park. The U.S. Geological Survey (USGS) and the National Park Service have collaborated on Cl flux monitoring towards this end since the 1970s. Researchers collected water samples from the major rivers in YNP, but funding restrictions, winter travel, and the great distances between sites limits the number of samples collected annually. The use of electrical conductivity, which is relatively easy to measure and can be automated, as a proxy for Cl enables a more consistent monitoring of thermal output. To accomplish this, it is crucial to accurately quantify the relationship between electrical conductivity, Cl, and other geothermal solutes (SO4, F, HCO3, SiO2, K, Li, B, and As) along the Madison, Firehole, Gibbon, Snake, Gardner, and Yellowstone Rivers. Conductivity measurements were made every 15 minutes adjacent to USGS stream gages, allowing for the determination of solute fluxes. In addition, continuous conductivity measurements can be used to identify changes in river chemistry as a result of geysers eruptions, rain events, or changes in thermal inputs as a result of earthquakes or other natural events. Depending on the site, we have collected 2 to 5 years of conductivity measurements. Except for some trace elements (Fe and Hg), most solutes behave conservatively, and the ratio of geothermal solute concentrations are constant. Hence, dissolved concentrations of Cl, SO4, F, HCO3, SiO2, K, Li, Ca, B, and As correlate well with conductivity (R2 > 0.96). The use of conductivity to estimate solute concentrations and fluxes will provide a greater understanding of the systematics of the Yellowstone thermal output and allow for monitoring of many more solutes at a much higher temporal frequency.

  5. Infrared Camera Diagnostic for Heat Flux Measurements on NSTX

    SciTech Connect

    D. Mastrovito; R. Maingi; H.W. Kugel; A.L. Roquemore

    2003-03-25

    An infrared imaging system has been installed on NSTX (National Spherical Torus Experiment) at the Princeton Plasma Physics Laboratory to measure the surface temperatures on the lower divertor and center stack. The imaging system is based on an Indigo Alpha 160 x 128 microbolometer camera with 12 bits/pixel operating in the 7-13 {micro}m range with a 30 Hz frame rate and a dynamic temperature range of 0-700 degrees C. From these data and knowledge of graphite thermal properties, the heat flux is derived with a classic one-dimensional conduction model. Preliminary results of heat flux scaling are reported.

  6. Estimating interfacial thermal conductivity in metamaterials through heat flux mapping

    SciTech Connect

    Canbazoglu, Fatih M.; Vemuri, Krishna P.; Bandaru, Prabhakar R.

    2015-04-06

    The variability of the thickness as well as the thermal conductivity of interfaces in composites may significantly influence thermal transport characteristics and the notion of a metamaterial as an effective medium. The consequent modulations of the heat flux passage are analytically and experimentally examined through a non-contact methodology using radiative imaging, on a model anisotropic thermal metamaterial. It was indicated that a lower Al layer/silver interfacial epoxy ratio of ∼25 compared to that of a Al layer/alumina interfacial epoxy (of ∼39) contributes to a smaller deviation of the heat flux bending angle.

  7. Toward evaluation of heat fluxes in the convective boundary layer

    SciTech Connect

    Sorbjan, Z.

    1995-05-01

    This article demonstrates that vertical profiles of the heat flux in the convective boundary layer can be diagnosed through an integration over height of the time change rates of observed potential temperature profiles. Moreover, the basic characteristics of the convective boundary layer, such as the mixed-layer height z{sub t}, the depth of the interfacial (entrainment) layer, and the heat flux zero-crossing height h{sub 0} can be uniquely evaluated based on a time evolution of potential temperature profiles in the lower atmosphere. 12 refs., 12 figs., 1 tab.

  8. Direct measurement of heat flux from cooling lake thermal imagery

    NASA Astrophysics Data System (ADS)

    Garrett, Alfred J.; Villa-Aleman, Eliel; Kurzeja, Robert J.; Pendergast, Malcolm M.

    2008-03-01

    Laboratory experiments show a linear relationship between the total heat flux from a water surface to air and the standard deviation of the surface temperature field, σ, derived from thermal images of the water surface over a range of heat fluxes from 400 to 1800 Wm -2. Thermal imagery and surface data were collected at two power plant cooling lakes to determine if the laboratory relationship between heat flux and σ exists in large heated bodies of water. The heat fluxes computed from the cooling lake data range from 200 to 1400 Wm -2. The linear relationship between σ and Q is evident in the cooling lake data, but it is necessary to apply band pass filtering to the thermal imagery to remove camera artifacts and non-convective thermal gradients. The correlation between σ and Q is improved if a correction to the measured σ is made that accounts for wind speed effects on the thermal convection. Based on more than a thousand cooling lake images, the correlation coefficients between σ and Q ranged from about 0.8 to 0.9.

  9. Heat flux instrumentation for Hyflite thermal protection system

    NASA Technical Reports Server (NTRS)

    Diller, T. E.

    1994-01-01

    Using Thermal Protection Tile core samples supplied by NASA, the surface characteristics of the FRCI, TUFI, and RCG coatings were evaluated. Based on these results, appropriate methods of surface preparation were determined and tested for the required sputtering processes. Sample sensors were fabricated on the RCG coating and adhesion was acceptable. Based on these encouraging results, complete Heat Flux Microsensors were fabricated on the RCG coating. The issue of lead attachment was addressed with the annnealing and welding methods developed at NASA Lewis. Parallel gap welding appears to be the best method of lead attachment with prior heat treatment of the sputtered pads. Sample Heat Flux Microsensors were submitted for testing in the NASA Ames arc jet facility. Details of the project are contained in two attached reports. One additional item of interest is contained in the attached AIAA paper, which gives details of the transient response of a Heat Flux Microsensors in a shock tube facility at Virginia Tech. The response of the heat flux sensor was measured to be faster than 10 micro-s.

  10. DIRECT MEASUREMENT OF HEAT FLUX FROM COOLING LAKE THERMAL IMAGERY

    SciTech Connect

    Garrett, A; Eliel Villa-Aleman, E; Robert Kurzeja, R; Malcolm Pendergast, M; Timothy Brown, T; Saleem Salaymeh, S

    2007-12-19

    Laboratory experiments show a linear relationship between the total heat flux from a water surface to air and the standard deviation of the surface temperature field, {sigma}, derived from thermal images of the water surface over a range of heat fluxes from 400 to 1800 Wm{sup -2}. Thermal imagery and surface data were collected at two power plant cooling lakes to determine if the laboratory relationship between heat flux and {sigma} exists in large heated bodies of water. The heat fluxes computed from the cooling lake data range from 200 to 1400 Wm{sup -2}. The linear relationship between {sigma} and Q is evident in the cooling lake data, but it is necessary to apply band pass filtering to the thermal imagery to remove camera artifacts and non-convective thermal gradients. The correlation between {sigma} and Q is improved if a correction to the measured {sigma} is made that accounts for wind speed effects on the thermal convection. Based on more than a thousand cooling lake images, the correlation coefficients between {sigma} and Q ranged from about 0.8 to 0.9.

  11. Liquid Argon Maximm Convective Heat Flux vs. Liquid Depth

    SciTech Connect

    Peterson, T.; /Fermilab

    1990-01-12

    In order to help answer questions about the magnitude of heat flux to the liquid argon in a liquid argon calorimeter which could cause boiling (bubbles), calculations estimating the heat flux which can be removed by free convection were made in February, 1988. These calculations are intended to be an estimate of the heat flux above which boiling would occur. No formal writeup was made of these calculations, although the graph dated 3 Feb 88 and revised (adding low-velocity forced convection lines) 19 Feb 88 was presented in several meetings and widely distributed. With this description of the calculations, copies of the original graph and calculations are being added to the D0 Engineering Note files. The liquid argon surface is in equilibrium with argon vapor at a pressure of 1.3 bar, so the surface is at 89.70 K. The liquid is entirely at this surface temperature throughout the bulk of the volume, except locally where it is warmed by a solid surface at a higher temperature than the bulk liquid. This surface temperature is taken to be the boiling temperature of argon at the pressure corresponding to 1.3 bar plus the liquid head; hence it is a function of depth below the surface. The free and forced convection correlations used are 'from Kreith, 'Heat Transfer', for heated flat plates in a large (i.e., no other objects nearby enough to disturb the flow) uniform volume of fluid. Heat flux is a function of plate size, really length along the flow path (since a boundary layer increases in thickness starting from the leading edge of the plate), and orientation (i.e., vertical or horizontal). The maximum heat flux which can be carried away by free convection (i.e., the heat flux above which boiling occurs) is .001 W/sq.cm. at 4 inches below the surface and 0.1 to 0.2 W/sq.cm. 15 feet below the surface. Forced convection over a 1 cm plate with a fluid velocity of 1 cm/sec, or a 10 cm plate at 10 cm/sec, is about like free convection. The line for much higher heat flux is

  12. Maximum allowable heat flux for a submerged horizontal tube bundle

    SciTech Connect

    McEligot, D.M. |

    1996-12-31

    For application to industrial heating of large pools by immersed heat exchangers, the so called maximum allowable (or critical) heat flux is studied for unconfined tube bundles aligned horizontally in a pool without forced flow. This is the condition at which vapor blanketing is expected to be initiated. Phenomenological considerations demonstrate why the maximum allowable heat flux would be expected to be less than for single tubes. Hydrodynamic theory is applied to extend the results of Lienhard and Dhir to large submerged bundles and the consequent correlation is compared to the correlation of Palen and Small and the limited data available for saturated conditions. To date the main conclusion is that estimates of q{double_prime}{sub chf} are highly uncertain for this configuration.

  13. Spatial resolution of subsurface anthropogenic heat fluxes in cities

    NASA Astrophysics Data System (ADS)

    Benz, Susanne; Bayer, Peter; Menberg, Kathrin; Blum, Philipp

    2015-04-01

    Urban heat islands in the subsurface contain large quantities of energy in the form of elevated groundwater temperatures caused by anthropogenic heat fluxes (AHFS) into the subsurface. Hence, the objective of this study is to exemplarily quantify these AHFS and the generated thermal powers in two German cities, Karlsruhe and Cologne. A two-dimensional (2D) statistical analytical model of the vertical subsurface anthropogenic heat fluxes across the unsaturated zone was developed. The model consists of a so-called Local Monte Carlo approach that introduces a spatial representation of the following sources of AHFS: (1) elevated ground surface temperatures, (2) basements, (3) sewage systems, (4) sewage leakage, (5) subway tunnels, and (6) district heating networks. The results show that district heating networks induce the largest local AHFS with values larger than 60 W/m2 and one order of magnitude higher than the other evaluated heat sources. Only sewage pipes and basements reaching into the groundwater cause equally high heat fluxes, with maximal values of 40.37 W/m2 and 13.60 W/m2, respectively. While dominating locally, the district heating network is rather insignificant for the citywide energy budget in both urban subsurfaces. Heat from buildings (1.51 ± 1.36 PJ/a in Karlsruhe; 0.31 ± 0.14 PJ/a in Cologne) and elevated GST (0.34 ± 0.10 PJ/a in Karlsruhe; 0.42 ± 0.13 PJ/a in Cologne) are dominant contributors to the anthropogenic thermal power of the urban aquifer. In Karlsruhe, buildings are the source of 70% of the annual heat transported into the groundwater, which is mainly caused by basements reaching into the groundwater. A variance analysis confirms these findings: basement depth is the most influential factor to citywide thermal power in the studied cities with high groundwater levels. The spatial distribution of fluxes, however, is mostly influenced by the prevailing thermal gradient across the unsaturated zone. A relatively cold groundwater

  14. Heat flux measurements for use in physiological and clothing research.

    PubMed

    Niedermann, R; Psikuta, A; Rossi, R M

    2014-08-01

    Scientists use passive heat flow meters to measure body heat exchanges with the environment. In recent years, several such sensors have been developed and concerns about their proper calibration have been addressed. However, calibration methods have differed in the geometry of the heated device as well as in the heat transfer mechanism. Therefore, a comparison of calibration methods is needed in order to understand the obtained differences in calibration lines. We chose three commercially available heat flux sensors and placed them on four different heated devices: a hot plate, double hot plate, nude cylinder and a cylinder covered with a spacer material. We found differences between the calibration line of the manufacturer and our own measurements, especially when forced convection was involved as the main heat transfer mechanism. The results showed clearly that the calibration method should be chosen according to the intended purpose of use. In addition, we recommend use a thin, light heat flux sensor with good thermal conduction in human subject studies.

  15. Heat flux measurements for use in physiological and clothing research

    NASA Astrophysics Data System (ADS)

    Niedermann, R.; Psikuta, A.; Rossi, R. M.

    2014-08-01

    Scientists use passive heat flow meters to measure body heat exchanges with the environment. In recent years, several such sensors have been developed and concerns about their proper calibration have been addressed. However, calibration methods have differed in the geometry of the heated device as well as in the heat transfer mechanism. Therefore, a comparison of calibration methods is needed in order to understand the obtained differences in calibration lines. We chose three commercially available heat flux sensors and placed them on four different heated devices: a hot plate, double hot plate, nude cylinder and a cylinder covered with a spacer material. We found differences between the calibration line of the manufacturer and our own measurements, especially when forced convection was involved as the main heat transfer mechanism. The results showed clearly that the calibration method should be chosen according to the intended purpose of use. In addition, we recommend use a thin, light heat flux sensor with good thermal conduction in human subject studies.

  16. Residential heating costs: a comparison of geothermal, solar and conventional resources

    SciTech Connect

    Bloomster, C.H.; Garrett-Price, B.A.; Fassbender, L.L.

    1980-08-01

    The costs of residential heating throughout the United States using conventional, solar, and geothermal energy were determined under current and projected conditions. These costs are very sensitive to location - being dependent on the local prices of conventional energy supplies, local solar insolation, cimate, and the proximity and temperature of potential geothermal resources. The sharp price increases in imported fuels during 1979 and the planned decontrol of domestic oil and natural gas prices have set the stage for geothermal and solar market penetration in the 1980's.

  17. The possibilities of utilisation of heat from Tattapani Geothermal field, India

    SciTech Connect

    Sarolkar, P.B.; Pitale, U.L.

    1996-12-31

    The Tattapani Geothermal field produces + 1800 1pm thermal water of 100{degrees}C from five production wells. The hot water production can sustain electricity production of 300 kWe by using a binary cycle power plant. The heat energy of effluent water from power plant can be utilized for direct heat utilization on horticulture, aquaculture, cold storage, silviculture etc; to augment the economics of the power plant be spot can be developed as a centre for tourist attraction by constructing botanical park, greenhouse, geyser show and crocodile farm. The direct heat utilization shemes can be planned in cascading order to achieve maximum utility of thermal water. Additional deep drilling is essential for optimum commercial utilization of the Geothermal energy. The direct heat utilisation shemes along with binary cycle power plant may help in development of the geothermal energy and boosting the economy of this region.

  18. Modeling of heat extraction from variably fractured porous media in Enhanced Geothermal Systems

    DOE PAGES

    Hadgu, Teklu; Kalinina, Elena Arkadievna; Lowry, Thomas Stephen

    2016-01-30

    Modeling of heat extraction in Enhanced Geothermal Systems is presented. The study builds on recent studies on the use of directional wells to improve heat transfer between doublet injection and production wells. The current study focuses on the influence of fracture orientation on production temperature in deep low permeability geothermal systems, and the effects of directional drilling and separation distance between boreholes on heat extraction. The modeling results indicate that fracture orientation with respect to the well-pair plane has significant influence on reservoir thermal drawdown. As a result, the vertical well doublet is impacted significantly more than the horizontal wellmore » doublet« less

  19. Geothermal greenhouse heating facilities for the Klamath County Nursing Home, Klamath Falls, Oregon

    NASA Astrophysics Data System (ADS)

    1982-02-01

    The Klamath County Nursing Home, located in Klamath Falls, Oregon, was constructed in 1976. The building of 55,654 square feet currently houses care facilities for approximately 120 persons. During the initial planning for the nursing home, the present site was selected primarily on the basis of its geothermal resource. This resource currently provides space and domestic hot water heating for the nursing home, Merle West Medical Center and the Oregon Institute of Technology. The feasibility of installing a geothermal heating system in a planned greenhouse for the nursing home is explored. The greenhouse system would be tied directly to the existing hot water heating system for the nursing home.

  20. Integral Plug-Type Heat-Flux Gauge

    NASA Technical Reports Server (NTRS)

    Liebert, Curt H.; Koch, John, Jr.

    1991-01-01

    Integral thermoplug gauge measures flux of heat across specimen of material. New gauge not screwed or welded into place, but instead thermoplug and annulus electrical-discharge-machined (EDM) into specimen material. EDM process leaves no interface between material and thermoplug, thus inherently increasing gauge accuracy by eliminating interface and associated temperature discontinuity. Process also conducive to accurate fabrication of minute gauges.

  1. Light-intensity modulator withstands high heat fluxes

    NASA Technical Reports Server (NTRS)

    Maples, H. G.; Strass, H. K.

    1966-01-01

    Mechanism modulates and controls the intensity of luminous radiation in light beams associated with high-intensity heat flux. This modulator incorporates two fluid-cooled, externally grooved, contracting metal cylinders which when rotated about their longitudinal axes present a circular aperture of varying size depending on the degree of rotation.

  2. Numerical nonlinear inverse problem of determining wall heat flux

    NASA Astrophysics Data System (ADS)

    Zueco, J.; Alhama, F.; González Fernández, C. F.

    2005-03-01

    The inverse problem of determining time-variable surface heat flux in a plane wall, with constant or temperature dependent thermal properties, is numerically studied. Different kinds of incident heat flux, including rectangular waveform, are assumed. The solution is numerically solved as a function estimation problem, so that no a priori information for the functional waveforms of the unknown heat flux is needed. In all cases, a solution in the form of a piece-wise function is used to approach the incident flux. Transient temperature measurements at the boundary, from the solution of the direct problem, served as the simulated experimental data needed as input for the inverse analysis. Both direct and inverse heat conduction problems are solved using the network simulation method. The solution is obtained step-by-step by minimising the classical functional that compares the above input data with those obtained from the solution of the inverse problem. A straight line of variable slope and length is used for each one of the stretches of the desired solution. The influence of random error, number of functional terms and the effect of sensor location are studied. In all cases, the results closely agree with the solution.

  3. A microscale thermophoretic turbine driven by external diffusive heat flux

    NASA Astrophysics Data System (ADS)

    Yang, Mingcheng; Liu, Rui; Ripoll, Marisol; Chen, Ke

    2014-10-01

    We propose a theoretical prototype of a micro-scale turbine externally driven by diffusive heat flux without the need for macroscopic particle flux, which is in sharp contrast to conventional turbines. The prototypes are described analytically and validated by computer simulations. Our results indicate that a micro-scale turbine composed of anisotropic blades can rotate unidirectionally in an external temperature gradient due to the anisotropic thermophoresis effect. The rotational direction and speed depend on the temperature gradient, the geometry and the thermophoretic properties of the turbine. The proposed thermophoretic turbines can be experimentally realized and implemented on micro-devices such as computer-chips to recover waste heat or to facilitate cooling.We propose a theoretical prototype of a micro-scale turbine externally driven by diffusive heat flux without the need for macroscopic particle flux, which is in sharp contrast to conventional turbines. The prototypes are described analytically and validated by computer simulations. Our results indicate that a micro-scale turbine composed of anisotropic blades can rotate unidirectionally in an external temperature gradient due to the anisotropic thermophoresis effect. The rotational direction and speed depend on the temperature gradient, the geometry and the thermophoretic properties of the turbine. The proposed thermophoretic turbines can be experimentally realized and implemented on micro-devices such as computer-chips to recover waste heat or to facilitate cooling. Electronic supplementary information (ESI) available. See DOI: 10.1039/c4nr03990d

  4. U.S. Heat Demand by Sector for Potential Application of Direct Use Geothermal

    DOE Data Explorer

    Katherine Young

    2016-06-23

    This dataset includes heat demand for potential application of direct use geothermal broken down into 4 sectors: agricultural, commercial, manufacturing and residential. The data for each sector are organized by county, were disaggregated specifically to assess the market demand for geothermal direct use, and were derived using methodologies customized for each sector based on the availability of data and other sector-specific factors. This dataset also includes a paper containing a full explanation of the methodologies used.

  5. Geothermal heating from Pinkerton Hot Springs at Colorado Timberline Academy, Durango, Colorado. Final technical report

    SciTech Connect

    Allen, C.C.; Allen, R.W.; Beldock, J.

    1981-11-08

    The efforts to establish a greater pool of knowledge in the field of low temperature heat transfer for the application of geothermal spring waters to space heating are described. A comprehensive set of heat loss experiments involving passive radiant heating panels is conducted and the results presented in an easily interpretable form. Among the conclusions are the facts that heating a 65 to 70 F/sup 0/ space with 90 to 100 F/sup 0/ liquids is a practical aim. The results are compared with the much lower rates published in the American Society of Heating Refrigeration and Air Conditioning Engineers SYSTEMS, 1976. A heat exchange chamber consisting of a 1000 gallon three compartment, insulated and buried tank is constructed and a control and pumping building erected over the tank. The tank is intended to handle the flow of geothermal waters from Pinkerton Hot Springs at 50 GPM prior to the wasting of the spring water at a disposal location. Approximately 375,000 Btu per hour should be available for heating assuming a 15 F/sup 0/ drop in water temperature. A combination of the panel heat loss experiments, construction of the heat exchange devices and ongoing collection of heat loss numbers adds to the knowledge available to engineers in sizing low temperature heat systems, useful in both solar and geothermal applications where source temperature may be often below 110 F/sup 0/.

  6. Heat Mining or Replenishable Geothermal Energy? A Project for Advanced-Level Physics Students

    ERIC Educational Resources Information Center

    Dugdale, Pam

    2014-01-01

    There is growing interest in the use of low enthalpy geothermal (LEG) energy schemes, whereby heated water is extracted from sandstone aquifers for civic heating projects. While prevalent in countries with volcanic activity, a recently proposed scheme for Manchester offered the perfect opportunity to engage students in the viability of this form…

  7. A Comparison Study of Heat-Transfer Simulations in a Closed-Loop Geothermal Heat- Pump System

    NASA Astrophysics Data System (ADS)

    Kim, S.; Seol, Y.; Bae, G.; Lee, K.

    2006-12-01

    Calculating heat transfer, particularly at the boundary between two different materials with varying heat conductivities, often involves weighting the heat conductivities of the two materials. However, the validity of the weighting scheme would be weak for a system in which heat conductivities vary considerably. We implemented the concept of a heat-transfer coefficient into heat transfer simulations to replace the weighting schemes. The heat-transfer coefficient can be experimentally measured to capture heat transfer between two materials whose heat conductivities significantly differ. A numerical code incorporating the heat-transfer coefficient was developed for simulations of heat transfer in a geothermal heat pump system (GHP) that consists of heat pipes, enclosing grouting material, surrounding porous media, and ambient groundwater flow. The code was applied to a simplified closed-loop GHP system with a single U-shaped heat pipe, and temperature changes in the system with circulating water through the pipe were monitored. The simulated temperature distribution results from this code were compared with results using the conventional weighting schemes of TOUGH2, a widely accepted simulator for heat and water flow in geothermal systems. Detailed discussion on the comparison analysis will be presented.

  8. Forced Convection Boiling and Critical Heat Flux of Ethanol in Electrically Heated Tube Tests

    NASA Technical Reports Server (NTRS)

    Meyer, Michael L.; Linne, Diane L.; Rousar, Donald C.

    1998-01-01

    Electrically heated tube tests were conducted to characterize the critical heat flux (transition from nucleate to film boiling) of subcritical ethanol flowing at conditions relevant to the design of a regeneratively cooled rocket engine thrust chamber. The coolant was SDA-3C alcohol (95% ethyl alcohol, 5% isopropyl alcohol by weight), and tests were conducted over the following ranges of conditions: pressure from 144 to 703 psia, flow velocities from 9.7 to 77 ft/s, coolant subcooling from 33 to 362 F, and critical heat fluxes up to 8.7 BTU/in(exp 2)/sec. For the data taken near 200 psia, critical heat flux was correlated as a function of the product of velocity and fluid subcooling to within +/- 20%. For data taken at higher pressures, an additional pressure term is needed to correlate the critical heat flux. It was also shown that at the higher test pressures and/or flow rates, exceeding the critical heat flux did not result in wall burnout. This result may significantly increase the engine heat flux design envelope for higher pressure conditions.

  9. White dwarf heating and the ultraviolet flux in dwarf novae

    NASA Technical Reports Server (NTRS)

    Pringle, J. E.

    1988-01-01

    The heating of the outer layers of the white dwarf which is likely to occur during a dwarf nova outburst is investigated. It is shown that the decline in IUE flux, observed during quiescent intervals in the dwarf novae VW Hydri and WX Hydri, may be due to the outer layers cooling off once the heat source is removed. The calculations here assume uniformity of the heat source over the white dwarf surface. This is unlikely to be realized from disk accretion, and discussion is made of what further calculations are required.

  10. Geothermal direct-heat utilization assistance. Quarterly progress report, January--March 1993

    SciTech Connect

    Lienau, P.

    1993-03-30

    CHC (Geo-Heated Center) staff provided assistance to 103 requests from 26 states, and from Canada, Egypt, Mexico, China, Poland and Greece. A breakdown of the requests according to application include: space and district heating (19), geothermal heat pumps (24), greenhouses (10), aquaculture (4), industrial (4), equipment (3), resources (27), electric power (2) and other (20). Progress is reported on: (1) evaluation of lineshaft turbine pump problems, (2) pilot fruit drier and (3) geothermal district heating marketing tools and equipment investigation. Four presentations and two tours were conducted during the quarter, GHC Quarterly Bulletin Vol. 14, No. 4 was prepared, 14 volumes were added to the library and information was disseminated to 45 requests. Progress reports are on: (1) GHP Teleconference 93, (2) California Energy Buys Glass Mountain Prospect from Unocal and Makes Deal for Newberry Caldera, (3) New Power Plant Planned, (4) Vale to Get Power Plant, (5) BPA Approves Geothermal Project, (6) Update: San Bernardino Reservoir Study, (7) Twenty-nine Palms Geothermal Resources, (8) Geo-Ag Heat Center, Lake County, and (9) Update: Geothermal Wells at Alturas.

  11. Measurement of a surface heat flux and temperature

    NASA Technical Reports Server (NTRS)

    Davis, R. M.; Antoine, G. J.; Diller, T. E.; Wicks, A. L.

    1994-01-01

    The Heat Flux Microsensor is a new sensor which was recently patented by Virginia Tech and is just starting to be marketed by Vatell Corp. The sensor is made using the thin-film microfabrication techniques directly on the material that is to be measured. It consists of several thin-film layers forming a differential thermopile across a thermal resistance layer. The measured heat flux q is proportional to the temperature difference across the resistance layer q= k(sub g)/delta(sub g) x (t(sub 1) - T(sub 2)), where k(sub g) is the thermal conductivity and delta (sub g) is the thickness of the thermal resistance layer. Because the gages are sputter coated directly onto the surface, their total thickness is less than 2 micrometers, which is two orders of magnitude thinner than previous gages. The resulting temperature difference across the thermal resistance layer (delta is less than 1 micrometer) is very small even at high heat fluxes. To generate a measurable signal many thermocouple pairs are put in series to form a differential thermopile. The combination of series thermocouple junctions and thin-film design creates a gage with very attractive characteristics. It is not only physically non-intrusive to the flow, but also causes minimal disruption of the surface temperature. Because it is so thin, the response time is less than 20 microsec. Consequently, the frequency response is flat from 0 to over 50 kHz. Moreover, the signal of the Heat Flux Microsensor is directly proportional to the heat flux. Therefore, it can easily be used in both steady and transient flows, and it measures both the steady and unsteady components of the surface heat flux. A version of the Heat Flux Microsensor has been developed to meet the harsh demands of combustion environments. These gages use platinum and platinum-10 percent rhodium as the thermoelectric materials. The thermal resistance layer is silicon monoxide and a protective coating of Al2O3 is deposited on top of the sensor. The

  12. Measurement of a surface heat flux and temperature

    NASA Astrophysics Data System (ADS)

    Davis, R. M.; Antoine, G. J.; Diller, T. E.; Wicks, A. L.

    1994-04-01

    The Heat Flux Microsensor is a new sensor which was recently patented by Virginia Tech and is just starting to be marketed by Vatell Corp. The sensor is made using the thin-film microfabrication techniques directly on the material that is to be measured. It consists of several thin-film layers forming a differential thermopile across a thermal resistance layer. The measured heat flux q is proportional to the temperature difference across the resistance layer q= k(sub g)/delta(sub g) x (t(sub 1) - T(sub 2)), where k(sub g) is the thermal conductivity and delta (sub g) is the thickness of the thermal resistance layer. Because the gages are sputter coated directly onto the surface, their total thickness is less than 2 micrometers, which is two orders of magnitude thinner than previous gages. The resulting temperature difference across the thermal resistance layer (delta is less than 1 micrometer) is very small even at high heat fluxes. To generate a measurable signal many thermocouple pairs are put in series to form a differential thermopile. The combination of series thermocouple junctions and thin-film design creates a gage with very attractive characteristics. It is not only physically non-intrusive to the flow, but also causes minimal disruption of the surface temperature. Because it is so thin, the response time is less than 20 microsec. Consequently, the frequency response is flat from 0 to over 50 kHz. Moreover, the signal of the Heat Flux Microsensor is directly proportional to the heat flux. Therefore, it can easily be used in both steady and transient flows, and it measures both the steady and unsteady components of the surface heat flux. A version of the Heat Flux Microsensor has been developed to meet the harsh demands of combustion environments. These gages use platinum and platinum-10 percent rhodium as the thermoelectric materials. The thermal resistance layer is silicon monoxide and a protective coating of Al2O3 is deposited on top of the sensor. The

  13. MOC, Heat Storage and Surface Heat Flux in 2009/2010.

    NASA Astrophysics Data System (ADS)

    Wells, N. C.

    2012-04-01

    MONACO aims to study the linkages between the MOC at 26°N in the N.Atlantic , the heat and freshwater fluxes at 26N, and the seasonal and inter-annual heat and salt content changes in the upper 0-2000m of the water column between 10-70°N for the period from April 2004 to December 2010. In particular, the MOC event of 2009 when there was a 50% reduction in the overturning circulation, will be related to the changes in heat storage and surface heat flux. This unusual event will be placed in the context of longer records.

  14. Azimuthal Stress and Heat Flux In Radiatively Inefficient Accretion Flows

    NASA Astrophysics Data System (ADS)

    Devlen, Ebru

    2016-07-01

    Radiatively Inefficient Accretion Flows (RIAFs) have low radiative efficiencies and/or low accretion rates. The accreting gas may retain most of its binding energy in the form of heat. This lost energy for hot RIAFs is one of the problems heavily worked on in the literature. RIAF observations on the accretion to super massive black holes (e.g., Sagittarius A* in the center of our Galaxy) have shown that the observational data are not consistent with either advection-dominated accretion flow (ADAF) or Bondi models. For this reason, it is very important to theoretically comprehend the physical properties of RIAFs derived from observations with a new disk/flow model. One of the most probable candidates for definition of mass accretion and the source of excess heat energy in RIAFs is the gyroviscous modified magnetorotational instability (GvMRI). Dispersion relation is derived by using MHD equations containing heat flux term based on viscosity in the energy equation. Numerical solutions of the disk equations are done and the growth rates of the instability are calculated. This additional heat flux plays an important role in dissipation of energy. The rates of the angular momentum and heat flux which are obtained from numerical calculations of the turbulence brought about by the GVMRI are also discussed.

  15. Performance of thermal barrier coatings in high heat flux environments

    NASA Technical Reports Server (NTRS)

    Miller, R. A.; Berndt, C. C.

    1984-01-01

    Thermal barrier coatings were exposed to the high temperature and high heat flux produced by a 30 kW plasma torch. Analysis of the specimen heating rates indicates that the temperature drop across the thickness of the 0.038 cm ceramic layer was about 1100 C after 0.5 sec in the flame. An as-sprayed ZrO2-8 percent Y203 specimens survived 3000 of the 0.5 sec cycles with failing. Surface spalling was observed when 2.5 sec cycles were employed but this was attributed to uneven heating caused by surface roughness. This surface spalling was prevented by smoothing the surface with silicon carbide paper or by laser glazing. A coated specimen with no surface modification but which was heat treated in argon also did not surface spall. Heat treatment in air led to spalling in as early as 2 cycle from heating stresses. Failures at edges were investigated and shown to be a minor source of concern. Ceramic coatings formed from ZrO2-12 percent Y2O3 or ZrO2-20 percent Y2O3 were shown to be unsuited for use under the high heat flux conditions of this study.

  16. Performance of thermal barrier coatings in high heat flux environments

    NASA Technical Reports Server (NTRS)

    Miller, R. A.; Berndt, C. C.

    1984-01-01

    Thermal barrier coatings were exposed to the high temperature and high heat flux produced by a 30 kW plasma torch. Analysis of the specimen heating rates indicates that the temperature drop across the thickness of the 0.038 cm ceramic layer was about 1100 C after 0.5 sec in the flame. An as-sprayed ZrO2-8 percent Y2O3 specimens survived 3000 of the 0.5 sec cycles with falling. Surface spalling was observed when 2.5 sec cycles were employed but this was attributed to uneven heating caused by surface roughness. This surface spalling was prevented by smoothing the surface with silicon carbide paper or by laser glazing. A coated specimen with no surface modification but which was heat treated in argon also did not surface spall. Heat treatment in air led to spalling in as early as 1 cycle from heating stresses. Failures at edges were investigated and shown to be a minor source of concern. Ceramic coatings formed from ZrO2-12 percent Y2O3 or ZrO2-2O percent Y2O3 were shown to be unsuited for use under the high heat flux conditions of this study.

  17. Performance of thermal barrier coatings in high heat flux environments

    NASA Technical Reports Server (NTRS)

    Miller, R. A.; Berndt, C. C.

    1984-01-01

    Thermal barrier coatings were exposed to the high temperature and high heat flux produced by a 30 kW plasma torch. Analysis of the specimen heating rates indicates that the temperature drop across the thickness of the 0.038 cm ceramic layer was about 1100 C after 0.5 sec in the flame. An as-sprayed ZrO2-8%Y2O3 specimens survived 3000 of the 0.5 sec cycles with failing. Surface spalling was observed when 2.5 sec cycles were employed but this was attributed to uneven heating caused by surface roughness. This surface spalling was prevented by smoothing the surface with silicon carbide paper or by laser glazing. A coated specimen with no surface modification but which was heat treated in argon also did not surface spall. Heat treatment in air led to spalling in as early as 2 cycle from heating stresses. Failures at edges were investigated and shown to be a minor source of concern. Ceramic coatings formed from ZrO2-12%Y2O3 or ZrO2-20%Y2O3 were shown to be unsuited for use under the high heat flux conditions of this study.

  18. Global Intercomparison of 12 Land Surface Heat Flux Estimates

    NASA Technical Reports Server (NTRS)

    Jimenez, C.; Prigent, C.; Mueller, B.; Seneviratne, S. I.; McCabe, M. F.; Wood, E. F.; Rossow, W. B.; Balsamo, G.; Betts, A. K.; Dirmeyer, P. A.; Fisher, J. B.; Jung, M.; Kanamitsu, M.; Reichle, R. H.; Reichstein, M.; Rodell, M.; Sheffield, J.; Tu, K.; Wang, K.

    2011-01-01

    A global intercomparison of 12 monthly mean land surface heat flux products for the period 1993-1995 is presented. The intercomparison includes some of the first emerging global satellite-based products (developed at Paris Observatory, Max Planck Institute for Biogeochemistry, University of California Berkeley, University of Maryland, and Princeton University) and examples of fluxes produced by reanalyses (ERA-Interim, MERRA, NCEP-DOE) and off-line land surface models (GSWP-2, GLDAS CLM/ Mosaic/Noah). An intercomparison of the global latent heat flux (Q(sub le)) annual means shows a spread of approx 20 W/sq m (all-product global average of approx 45 W/sq m). A similar spread is observed for the sensible (Q(sub h)) and net radiative (R(sub n)) fluxes. In general, the products correlate well with each other, helped by the large seasonal variability and common forcing data for some of the products. Expected spatial distributions related to the major climatic regimes and geographical features are reproduced by all products. Nevertheless, large Q(sub le)and Q(sub h) absolute differences are also observed. The fluxes were spatially averaged for 10 vegetation classes. The larger Q(sub le) differences were observed for the rain forest but, when normalized by mean fluxes, the differences were comparable to other classes. In general, the correlations between Q(sub le) and R(sub n) were higher for the satellite-based products compared with the reanalyses and off-line models. The fluxes were also averaged for 10 selected basins. The seasonality was generally well captured by all products, but large differences in the flux partitioning were observed for some products and basins.

  19. Particle and heat flux measurements in PDX edge plasmas

    NASA Astrophysics Data System (ADS)

    Budny, R.; Manos, D.

    1984-05-01

    This paper describes the use of novel combined Langmuir-calorimeter probes to measure edge plasma conditions near the midplane in PDX. The probes consisted of up to five Langmuir probes and up to two calorimeters. Single and double probe characteristics yield ne and Tc which are compared with results derived from a triple probe analysis. The calorimeters measure heat flux in the electron and ion drift directions. This paper presents time-resolved radial profiles of ne, Te, VF (floating potential),and P (heat flux) during high power neutral beam-heated, single-null discharges and circular scoop limiter discharges. The temporal dependence of these quantities displays the previously observed behavior with respect to gross discharge characteristics; however, an additional dependence on confinement mode has been observed. During the H-mode of energy confinement, a transient depression of ne, Te, and P occur in the scrape-off plasma.

  20. Enceladus' extreme heat flux as revealed by its relaxed craters

    NASA Astrophysics Data System (ADS)

    Bland, Michael T.; Singer, Kelsi N.; McKinnon, William B.; Schenk, Paul M.

    2012-09-01

    Enceladus' cratered terrains contain large numbers of unusually shallow craters consistent with deformation by viscous relaxation of water ice under conditions of elevated heat flow. Here we use high-resolution topography to measure the relaxation fraction of craters on Enceladus far from the active South Pole. We find that many craters are shallower than expected, with craters as small as 2 km in diameter having relaxation fractions in excess of 90%. These measurements are compared with numerical simulations of crater relaxation to constrain the minimum heat flux required to reproduce these observations. We find that Enceladus' nominal cold surface temperature (70 K) and low surface gravity strongly inhibit viscous relaxation. Under such conditions less than 3% relaxation occurs over 2 Ga even for relatively large craters (diameter 24 km) and high, constant heat fluxes (150 mW m-2). Greater viscous relaxation occurs if the effective temperature at the top of the lithosphere is greater than the surface temperature due to insulating regolith and/or plume material. Even for an effective temperature of 120 K, however, heat fluxes in excess of 150 mW m-2 are required to produce the degree of relaxation observed. Simulations of viscous relaxation of Enceladus' largest craters suggest that relaxation is best explained by a relatively short-lived period of intense heating that decayed quickly. We show that infilling of craters by plume material cannot explain the extremely shallow craters at equatorial and higher northern latitudes. Thus, like Enceladus' tectonic terrains, the cratered regions of Enceladus have experienced periods of extreme heat flux.

  1. Constraints on hydrothermal heat flux through the oceanic lithosphere from global heat flow

    NASA Technical Reports Server (NTRS)

    Stein, Carol A.; Stein, Seth

    1994-01-01

    A significant discrepancy exists between the heat flow measured at the seafloor and the higher values predicted by thermal models of the cooling lithosphere. This discrepancy is generally interpreted as indicating that the upper oceanic crust is cooled significantly by hydrothermal circulation. The magnitude of this heat flow discrepancy is the primary datum used to estimate the volume of hydrothermal flow, and the variation in the discrepancy with lithospheric age is the primary constraint on how the hydrothermal flux is divided between near-ridge and off-ridge environments. The resulting estimates are important for investigation of both the thermal structure of the lithosphere and the chemistry of the oceans. We reevaluate the magnitude and age variation of the discrepancy using a global heat flow data set substantially larger than in earlier studies, and the GDHI (Global Depth and Heat Flow) model that better predicts the heat flow. We estimate that of the predicted global oceanic heat flux of 32 x 10(exp 12) W, 34% (11 x 10(exp 12) W) occurs by hydrothermal flow. Approximately 30% of the hydrothermal heat flux occurs in crust younger than 1 Ma, so the majority of this flux is off-ridge. These hydrothermal heat flux estimates are upper bounds, because heat flow measurements require sediment at the site and so are made preferentially at topographic lows, where heat flow may be depressed. Because the water temperature for the near-ridge flow exceeds that for the off-ridge flow, the near-ridge water flow will be even a smaller fraction of the total water flow. As a result, in estimating fluxes from geochemical data, use of the high water temperatures appropriate for the ridge axis may significantly overestimate the heat flux for an assumed water flux or underestimate the water flux for an assumed heat flux. Our data also permit improved estimates of the 'sealing' age, defined as the age where the observed heat flow approximately equals that predicted, suggesting

  2. Natural convection flow in porous enclosure with localized heating from below with heat flux

    NASA Astrophysics Data System (ADS)

    Siddiki, Md. Noor-A.-Alam; Molla, Md. Mamun; Saha, Suvash C.

    2016-07-01

    Unsteady natural convection flow in a two dimensional fluid saturated porous enclosure with localized heating from below with heat flux, symmetrical cooling from the sides and the insulated top wall has been investigated numerically. The governing equations are the Darcy's law for the porous media and the energy equation for the temperature field has been considered. The non-dimensional Darcy's law in terms of the stream function is solved by finite difference method using the successive over-relaxation (SOR) scheme and the energy equation is solved by Alternative Direction Alternative (ADI) scheme. The uniform heat flux source is located centrally at the bottom wall. The numerical results are presented in terms of the streamlines and isotherms, as well as the local and average rate of heat transfer for the wide range of the Darcy's Rayleigh number and the length of the heat flux source at the bottom wall.

  3. Physical mechanisms of heat, momentum and turbulence fluxes

    NASA Technical Reports Server (NTRS)

    Theon, John S.

    1987-01-01

    In a qualitative way, the physical mechanisms which generate fluxes of heat, momentum, and turbulence in the atmosphere are discussed. This material is presented to acquaint people with the Earth science aspects of turbulence as important processes in the atmosphere. To attempt to describe turbulent fluxes of heat, momentum, and moisture in precise mathematical detail becomes an intractable problem. It is burdened by an eighth order set of equations involving more variables than equations. It is a closure problem which requires complicated assumptions that are not necessarily always satisfied, variable boundary conditions, and sparse observational data. Therefore, we must approach the problem in a simplified manner to obtain any kind of solution involving the variables of shear, stress, and heat, moisture, and momentum fluxes. There are other problems, of course, in which the inclusion of the planetary boundary layer is extremely important. Air pollution studies, air-sea exchanges, mesoscale models, and so on, must account for the planetary layer in very specific terms. Some of the physical mechanisms that are involved in generating fluxes are described.

  4. So close, so different: geothermal flux shapes divergent soil microbial communities at neighbouring sites.

    PubMed

    Gagliano, A L; Tagliavia, M; D'Alessandro, W; Franzetti, A; Parello, F; Quatrini, P

    2016-03-01

    This study is focused on the (micro)biogeochemical features of two close geothermal sites (FAV1 and FAV2), both selected at the main exhalative area of Pantelleria Island, Italy. A previous biogeochemical survey revealed high CH4 consumption and the presence of a diverse community of methanotrophs at FAV2 site, whereas the close site FAV1 was apparently devoid of methanotrophs and recorded no CH4 consumption. Next-Generation Sequencing (NGS) techniques were applied to describe the bacterial and archaeal communities which have been linked to the physicochemical conditions and the geothermal sources of energy available at the two sites. Both sites are dominated by Bacteria and host a negligible component of ammonia-oxidizing Archaea (phylum Thaumarchaeota). The FAV2 bacterial community is characterized by an extraordinary diversity of methanotrophs, with 40% of the sequences assigned to Methylocaldum, Methylobacter (Gammaproteobacteria) and Bejerickia (Alphaproteobacteria); conversely, a community of thermo-acidophilic chemolithotrophs (Acidithiobacillus, Nitrosococcus) or putative chemolithotrophs (Ktedonobacter) dominates the FAV1 community, in the absence of methanotrophs. Since physical andchemical factors of FAV1, such as temperature and pH, cannot be considered limiting for methanotrophy, it is hypothesized that the main limiting factor for methanotrophs could be high NH4(+) concentration. At the same time, abundant availability of NH4(+) and other high energy electron donors and acceptors determined by the hydrothermal flux in this site create more energetically favourable conditions for chemolithotrophs that outcompete methanotrophs in non-nitrogen-limited soils.

  5. So close, so different: geothermal flux shapes divergent soil microbial communities at neighbouring sites.

    PubMed

    Gagliano, A L; Tagliavia, M; D'Alessandro, W; Franzetti, A; Parello, F; Quatrini, P

    2016-03-01

    This study is focused on the (micro)biogeochemical features of two close geothermal sites (FAV1 and FAV2), both selected at the main exhalative area of Pantelleria Island, Italy. A previous biogeochemical survey revealed high CH4 consumption and the presence of a diverse community of methanotrophs at FAV2 site, whereas the close site FAV1 was apparently devoid of methanotrophs and recorded no CH4 consumption. Next-Generation Sequencing (NGS) techniques were applied to describe the bacterial and archaeal communities which have been linked to the physicochemical conditions and the geothermal sources of energy available at the two sites. Both sites are dominated by Bacteria and host a negligible component of ammonia-oxidizing Archaea (phylum Thaumarchaeota). The FAV2 bacterial community is characterized by an extraordinary diversity of methanotrophs, with 40% of the sequences assigned to Methylocaldum, Methylobacter (Gammaproteobacteria) and Bejerickia (Alphaproteobacteria); conversely, a community of thermo-acidophilic chemolithotrophs (Acidithiobacillus, Nitrosococcus) or putative chemolithotrophs (Ktedonobacter) dominates the FAV1 community, in the absence of methanotrophs. Since physical andchemical factors of FAV1, such as temperature and pH, cannot be considered limiting for methanotrophy, it is hypothesized that the main limiting factor for methanotrophs could be high NH4(+) concentration. At the same time, abundant availability of NH4(+) and other high energy electron donors and acceptors determined by the hydrothermal flux in this site create more energetically favourable conditions for chemolithotrophs that outcompete methanotrophs in non-nitrogen-limited soils. PMID:26560641

  6. Spectral estimates of net radiation and soil heat flux

    USGS Publications Warehouse

    Daughtry, C.S.T.; Kustas, W.P.; Moran, M.S.; Pinter, P. J.; Jackson, R. D.; Brown, P.W.; Nichols, W.D.; Gay, L.W.

    1990-01-01

    Conventional methods of measuring surface energy balance are point measurements and represent only a small area. Remote sensing offers a potential means of measuring outgoing fluxes over large areas at the spatial resolution of the sensor. The objective of this study was to estimate net radiation (Rn) and soil heat flux (G) using remotely sensed multispectral data acquired from an aircraft over large agricultural fields. Ground-based instruments measured Rn and G at nine locations along the flight lines. Incoming fluxes were also measured by ground-based instruments. Outgoing fluxes were estimated using remotely sensed data. Remote Rn, estimated as the algebraic sum of incoming and outgoing fluxes, slightly underestimated Rn measured by the ground-based net radiometers. The mean absolute errors for remote Rn minus measured Rn were less than 7%. Remote G, estimated as a function of a spectral vegetation index and remote Rn, slightly overestimated measured G; however, the mean absolute error for remote G was 13%. Some of the differences between measured and remote values of Rn and G are associated with differences in instrument designs and measurement techniques. The root mean square error for available energy (Rn - G) was 12%. Thus, methods using both ground-based and remotely sensed data can provide reliable estimates of the available energy which can be partitioned into sensible and latent heat under nonadvective conditions. ?? 1990.

  7. Feasibility and Supply Analysis of U.S. Geothermal District Heating and Cooling System

    NASA Astrophysics Data System (ADS)

    He, Xiaoning

    Geothermal energy is a globally distributed sustainable energy with the advantages of a stable base load energy production with a high capacity factor and zero SOx, CO, and particulates emissions. It can provide a potential solution to the depletion of fossil fuels and air pollution problems. The geothermal district heating and cooling system is one of the most common applications of geothermal energy, and consists of geothermal wells to provide hot water from a fractured geothermal reservoir, a surface energy distribution system for hot water transmission, and heating/cooling facilities to provide water and space heating as well as air conditioning for residential and commercial buildings. To gain wider recognition for the geothermal district heating and cooling (GDHC) system, the potential to develop such a system was evaluated in the western United States, and in the state of West Virginia. The geothermal resources were categorized into identified hydrothermal resources, undiscovered hydrothermal resources, near hydrothermal enhanced geothermal system (EGS), and deep EGS. Reservoir characteristics of the first three categories were estimated individually, and their thermal potential calculated. A cost model for such a system was developed for technical performance and economic analysis at each geothermally active location. A supply curve for the system was then developed, establishing the quantity and the cost of potential geothermal energy which can be used for the GDHC system. A West Virginia University (WVU) case study was performed to compare the competiveness of a geothermal energy system to the current steam based system. An Aspen Plus model was created to simulate the year-round campus heating and cooling scenario. Five cases of varying water flow rates and temperatures were simulated to find the lowest levelized cost of heat (LCOH) for the WVU case study. The model was then used to derive a levelized cost of heat as a function of the population density

  8. Geothermal space heating for the Senior Citizens Center at Truth or Consequences, New Mexico. Final report

    SciTech Connect

    Mancini, T.R.; Chaturvedi, L.N.; Gebhard, T.G.

    1982-03-01

    A demonstration project to heat the Senior Citizens Center at Truth or Consequences, New Mexico with geothermal waters is described. There were three phases to the project: Phase I - design and permitting; Phase II - installation of the heating system and well drilling; and Phase III - operation of the system. All three phases went well and there was only one major problem encountered. This was that the well which was drilled to serve as the geothermal source was dry. This could not have been anticipated and there was, as a contingency plan, the option of using an existing sump in the Teen Center adjacent to the Senior Citizens Center as the geothermal source. The system was made operational in August of 1981 and has virtually supplied all of the heat to the Senior Citizens Center during this winter.

  9. Geothermal anomalies in central Texas - Darcy's Law versus the heat-flow equation

    SciTech Connect

    Woodruff, C.M. Jr.; Ruscetta, C.A.

    1982-07-01

    Data on geothermal anomalies within the Edwards Limestone of Central Texas is presented, and the premises underlying both the definition and the assessment of low-temperature geothermal resources are critiqued. The focus is on stratigraphic aquifers that compose basinal hydrodynamic systems characteristic of many of the Plain Sthates. It is concluded that in most near-surface areas ground-water flow, not heat flow, probably determines local thermal regimes; that the presumed heat flow anomaly has a hydrodynamic origin rather than a conductive (deep crystal) source; and that the data indicate that the heat-flow equation should be applied guardedly in assessing geothermal resource potential at depths shallower than 4000 ft in basinal areas of the midcontinents. (MJF)

  10. Heat flux and oxygen consumption of the pregnant uterus.

    PubMed

    Rudelstorfer, R; Tabsh, K; Khoury, A; Nuwayhid, B; Brinkman, C R; Assali, N S

    1986-02-01

    Heat flux (conductive and convective heat) and oxygen consumption of the pregnant uterus and its content were measured simultaneously in the same group of pregnant ewes during the acute postoperative period, during a chronic resting period, and during alpha- and beta-adrenergic-receptor stimulation with norepinephrine and ritodrine. Results indicated four conclusions. First, an excellent correlation existed between heat flux and oxygen consumption in the acute and chronic resting condition as well as during increasing uteroplacental vascular resistance and decreasing blood flow produced by norepinephrine infusion; the correlation was not as good during ritodrine infusion. Second, during rest, about 85% of heat generated by the pregnant uterus is eliminated through the uteroplacental circulation while the remaining heat diffuses through the myometrium. Third, during decreasing uteroplacental blood flow and elevated resistance, the pregnant uterus is able to maintain a normal thermostasis by widening the temperature difference in the blood entering and leaving the uterus and by increasing the myometrial heat exchange; oxygen consumption also is maintained at normal level through increase in oxygen extraction. Fourth, with the exception of uteroplacental circulation, the circulatory, metabolic, and thermal conditions of the pregnant ewe are not different after 5 hours from 5 to 7 days after the surgical procedure. PMID:3004223

  11. Scaling Relationships for ELM Diverter Heat Flux on DIII D

    NASA Astrophysics Data System (ADS)

    Peters, E. A.; Makowski, M. A.; Leonard, A. W.

    2015-11-01

    Edge Localized Modes (ELMs) are periodic plasma instabilities that occur during H-mode operation in tokamaks. Left unmitigated, these instabilities result in concentrated particle and heat fluxes at the divertor and stand to cause serious damage to the plasma facing components of tokamaks. The purpose of this research is to find scaling relationships that predict divertor heat flux due to ELMs based on plasma parameters at the time of instability. This will be accomplished by correlating characteristic ELM parameters with corresponding plasma measurements and analyzing the data for trends. One early assessment is the effect of the heat transmission coefficient ? on the in/out asymmetry of the calculated ELM heat fluxes. Using IR camera data, further assessments in this study will continue to emphasize in/out asymmetry in ELMs, as this has important implications for ITER operation. Work supported in part by the US DOE, DE-AC52-07NA27344, DE-FC02-04ER54698, Office of Workforce Development for Teachers and Scientists (WDTS) under the Science Undergraduate Laboratory Internships Program (SULI).

  12. Heat flux in soil amended with biochar: modelling approach

    NASA Astrophysics Data System (ADS)

    Usowicz, Boguslaw; Lipiec, Jerzy; Lukowski, Mateusz; Marczewski, Wojciech; Usowicz, Jerzy

    2016-04-01

    Temperature of soil has important influences on many soil processes and plant growth. It depends on the energy balance on the active surface, where the process of energy exchange between the Earth's surface and the atmosphere occurs. Heat flux is one of the components of the energy balance and can be influenced by biochar application to the soil, along with inherent texture and variables: moisture, density, and temperature of soil, as well as external conditions like climate, topography and surface properties related to the land use and vegetation cover. In this work we present the statistical-physical modelling approach for predicting the thermal conductivity and soil heat flux dynamics, based on temperature and soil moisture measurements, obtained from bare and grass fields with different rates of biochar. Adding biochar caused significant reduction of the thermal conductivity, diffusivity and heat capacity of the soil in the dry state and their significant increase in the wet state. The soil heat fluxes in bare and grassed soil were similar or different, depending on weather conditions, insolation, plant growth stage and changed with the soil depth, moisture as well as the rate of biochar applied.

  13. Effect of thermal-hydrogeological and borehole heat exchanger properties on performance and impact of vertical closed-loop geothermal heat pump systems

    NASA Astrophysics Data System (ADS)

    Dehkordi, S. Emad; Schincariol, Robert A.

    2013-10-01

    Ground-source geothermal systems are drawing increasing attention and popularity due to their efficiency, sustainability and being implementable worldwide. Consequently, design software and regulatory guidelines have been developed. Interaction with the subsurface significantly affects the thermal performance, sustainability, and impacts of such systems. Reviewing the related guidelines and the design software, room for improvement is evident, especially in regards to interaction with groundwater movement. In order to accurately evaluate the thermal effect of system and hydrogeological properties on a borehole heat exchanger, a fully discretized finite-element model is used. Sensitivity of the loop outlet temperatures and heat exchange rates to hydrogeological, system and meteorological factors (i.e. groundwater flux, thermal conductivity and volumetric heat capacity of solids, porosity, thermal dispersivity, grout thermal conductivity, background and inlet temperatures) are analyzed over 6-month and 25-year operation periods. Furthermore, thermal recovery during 25 years after system decommissioning has been modeled. The thermal plume development, transport and dissipation are also assessed. This study shows the importance of subsurface thermal conductivity, groundwater flow (flux > 10-7 m/s), and background and inlet temperature on system performance and impact. It also shows the importance of groundwater flow (flux > 10-8 m/s) on thermal recovery of the ground over other factors.

  14. Heat flux sensors for burner liners and turbine blades and vanes

    NASA Technical Reports Server (NTRS)

    Alwang, W. G.

    1982-01-01

    The technology of heat flux measurement is addressed. The development of total heat flux sensors for burner liners and also the demonstration of total and radiant heat flux sensors in a combustor test is covered. A thorough review of potential approaches is conducted including both transient and steady state measurements. Measurement of total heat flux was emphasized, consequently configurations are sought which produce minimum disturbance to the heat flux which would be present without the sensor in place. Approaches to the turbine blade and vane heat flux sensor program are discussed.

  15. A 2-D imaging heat-flux gauge

    SciTech Connect

    Noel, B.W.; Borella, H.M. ); Beshears, D.L.; Sartory, W.K.; Tobin, K.W.; Williams, R.K. ); Turley, W.D. . Santa Barbara Operations)

    1991-07-01

    This report describes a new leadless two-dimensional imaging optical heat-flux gauge. The gauge is made by depositing arrays of thermorgraphic-phosphor (TP) spots onto the faces of a polymethylpentene is insulator. In the first section of the report, we describe several gauge configurations and their prototype realizations. A satisfactory configuration is an array of right triangles on each face that overlay to form squares when the gauge is viewed normal to the surface. The next section of the report treats the thermal conductivity of TPs. We set up an experiment using a comparative longitudinal heat-flow apparatus to measure the previously unknown thermal conductivity of these materials. The thermal conductivity of one TP, Y{sub 2}O{sub 3}:Eu, is 0.0137 W/cm{center dot}K over the temperature range from about 300 to 360 K. The theories underlying the time response of TP gauges and the imaging characteristics are discussed in the next section. Then we discuss several laboratory experiments to (1) demonstrate that the TP heat-flux gauge can be used in imaging applications; (2) obtain a quantum yield that enumerates what typical optical output signal amplitudes can be obtained from TP heat-flux gauges; and (3) determine whether LANL-designed intensified video cameras have sufficient sensitivity to acquire images from the heat-flux gauges. We obtained positive results from all the measurements. Throughout the text, we note limitations, areas where improvements are needed, and where further research is necessary. 12 refs., 25 figs., 4 tabs.

  16. Heat Flow and Geothermal Potential in the South-Central United States

    SciTech Connect

    Negraru, Petru T. Blackwell, David D.; Erkan, Kamil

    2008-12-15

    Geothermal exploration is typically limited to high-grade hydrothermal reservoirs that are usually found in the western United States, yet large areas with subsurface temperatures above 150 deg. C at economic drilling depths can be found east of the Rocky Mountains. The object of this paper is to present new heat flow data and to evaluate the geothermal potential of Texas and adjacent areas. The new data show that, west of the Ouachita Thrust Belt, the heat flow values are lower than east of the fault zone. Basement heat flow values for the Palo Duro and Fort Worth Basins are below 50 mW/m{sup 2} while, in the frontal zone of the belt, they can exceed 60 mW/m{sup 2}. Further east, along the Balcones fault system the heat flow is in general higher than 55 mW/m{sup 2}. The eastern most heat flow sites are in Louisiana and they show very high heat flow (over 80 mW/m{sup 2}), which is associated with the apparently highly radioactive basement of the Sabine uplift. The geothermal resource in this area is large and diverse, and can be divided in high grade (temperature above 150 deg. C) convective systems, conductive based enhanced geothermal systems and geothermal/geopressured systems. One of the most attractive areas east of the cordillera extends from eastern Texas across Louisiana and Arkansas to western Mississippi. Here temperatures reach exploitation range at depths below 4 km, and tapping such a resource from shut in hydrocarbon fields is relatively easy. The initial costs of the development can be greatly reduced if existing hydrocarbon infrastructure is used, and therefore using shut-in hydrocarbon fields for geothermal purposes should not be neglected.

  17. Generic Guide Specification for Geothermal Heat Pump Systems

    SciTech Connect

    Thomas, WKT

    2000-04-12

    The attached Geothermal (Ground-Source) Heat Pump (GHP) Guide Specifications have been developed by Oak Ridge National Laboratory (ORNL) with the intent to assist federal agency sites and engineers in the preparation of construction specifications for GHP projects. These specifications have been developed in the industry-standard Construction Specification Institute (CSI) format and cover several of the most popular members of the family of GHP systems. These guide specifications are applicable to projects whether the financing is with conventional appropriations, arranged by GHP specialty ESCOs under the U.S. Department of Energy's Technology-Specific GHP Super ESPCs, arranged by utilities under Utility Energy Service Contracts (UESCs) or arranged by generalist ESCOs under the various regional ESPCs. These specifications can provide several benefits to the end user that will help ensure successful GHP system installations. GHP guide specifications will help to streamline the specification development, review, and approval process because the architecture and engineering (AE) firm will be working from the familiar CSI format instead of developing the specifications from other sources. The guide specifications help to provide uniformity, standardization, and consistency in both the construction specifications and system installations across multiple federal sites. This standardization can provide future benefits to the federal sites in respect to both maintenance and operations. GHP guide specifications can help to ensure that the agency is getting its money's worth from the GHP system by preventing the use of marginal or inferior components and equipment. The agency and its AE do not have to start from scratch when developing specifications and can use the specification as a template and/or a checklist in developing both the design and the contract documents. The guide specifications can save project costs by reducing the engineering effort required during the

  18. Use of geothermal heat for sugar refining in Imperial County. Final report, Phase I

    SciTech Connect

    Not Available

    1980-12-01

    The objective of the three-phase Holly Sugar Geothermal Project was to replace fossil fuels with geothermal energy for sugar beet processing at the Holly Sugar plant located in Brawley, California, in a technically straightforward, economically sound and environmentally acceptable manner. The first phase of the project, discussed in this final report, encompassed the design and analysis of a geothermal industrial heat system for Holly Sugar and addresses: (1) assessment of the geothermal resource; (2) development of a preliminary system design; (3) analysis and publication of an environmental analysis and monitoring report; (4) preliminary economic analyses; (5) dissemination of project related information; and (6) the development of a proposal for the follow-on phases.

  19. Union County - La Grande, Oregon geothermal district heating: feasibility assessment. Final report

    SciTech Connect

    Jenkins, H. II; Giddings, M.; Hanson, P.

    1982-09-01

    This report presents an assessment of geothermal district heating in the City of La Grande, Oregon. Eight study area districts were analyzed to determine their economic feasibility. Results from the analyses conclude that certain districts within the City of La Grande are economically feasible if certain assumptions are correct. Development of geothermal district heating for these areas would provide direct energy and dollar savings to the building owners and would also provide direct and indirect benefits to low and moderate income households within the City.

  20. Double-diffusive convection as a mechanism for transferring heat and mass within the Salton Sea geothermal brine

    SciTech Connect

    Fournier, Robert O.

    1988-01-01

    H. C. Helgeson noted in 1968 that the salinity of the brine in the geothermal reservoir within the Salton Sea geothermal system generally increases from the top to the bottom and from the center to the sides. He also noted that pressure measurements at perforations in cased wells seemed to indicate that the formation fluids at the depths of production have a specific density about equal to 1, and that hot concentrated brines apparently exist in pressure equilibrium with comparatively cold dilute pore waters in the surrounding rocks. Since 1968 there have been no published reports that dispute these observations. However, a very high heat flux through the top of the system seems to require a substantial component of convective transfer of heat beneath an impermeable cap, whereas the apparent salinity gradient with depth seems to require little or no free convection of brine. This paradox may be resolved if double-diffusive convection is the main process that controls the depth-temperature-salinity relations. Such convection provides a mechanism for transferring heat from the bottom to the top of the hydrothermal system while maintaining vertical and horizontal salinity gradients—densities remaining close to unity. In 1981, Griffiths showed experimentally that layered double-diffusive convection cells may develop in porous media when hot saline waters underlie more dilute cooler waters. However, nagging questions remain about whether fluid densities within the Salton Sea geothermal system really adjust to unity in response to changing temperature and salinity at depths greater than about 1 km. The State 2-14 well, the Salton Sea Scientific Drill Hole, has provided one high-quality data point for a depth interval of 1,865-1,877 m, where the temperature is about 305º C. The calculated density of the pre-flashed reservoir fluid sampled from that depth is 1.0008 ± 0.0023.

  1. Heat flow and temperature-depth curves throughout Alaska: finding regions for future geothermal exploration

    NASA Astrophysics Data System (ADS)

    Batir, Joseph F.; Blackwell, David D.; Richards, Maria C.

    2016-06-01

    The objective of this research is to contribute to the understanding of the thermal regime of Alaska and its relationship to geology, regional tectonics, and to suggest potential sites for future geothermal energy production. New heat flow data were collected and are combined with existing published and unpublished data, although large sections of Alaska still lack data. Fault traces were implemented into the heat flow contouring as an additional gridding constraint, to incorporate both heat flow measurements and geology. New heat flow data supported the use of geologic trends in the heat flow mapping procedure, and a heat flow map of Alaska was produced with this added constraint. The multi-input contouring strategy allows production of a map with a regional interpretation of heat flow, in addition to site-specific heat flow and thermal model interpretations in areas with sufficient data density. Utilizing the new heat flow map, temperature-at-depth curves were created for example areas. Temperature-at-depth curves are calculated to 10 km depth for the areas of Anchorage, Fairbanks, Juneau, the Alaska Peninsula, Bristol Bay, and the Copper River Basin. The temperatures-at-depth predicted near the population centers of Anchorage and Juneau are relatively low, limiting the geothermal resource potential. The Fairbanks area temperature estimates are near conventional power production temperatures (150 °C) between 3.5 and 4 km. All data areas, except at Juneau, have temperatures sufficient for low temperature geothermal applications (40 °C) by 2 km. A high heat flow region exists within the Aleutian Volcanic Arc, although new data show heat flow variations from 59 to 120 mW m-2, so individual geothermal resources within the arc will be irregularly located.

  2. Heat flow and temperature-depth curves throughout Alaska: finding regions for future geothermal exploration

    NASA Astrophysics Data System (ADS)

    Batir, Joseph F.; Blackwell, David D.; Richards, Maria C.

    2016-06-01

    The objective of this research is to contribute to the understanding of the thermal regime of Alaska and its relationship to geology, regional tectonics, and to suggest potential sites for future geothermal energy production. New heat flow data were collected and are combined with existing published and unpublished data, although large sections of Alaska still lack data. Fault traces were implemented into the heat flow contouring as an additional gridding constraint, to incorporate both heat flow measurements and geology. New heat flow data supported the use of geologic trends in the heat flow mapping procedure, and a heat flow map of Alaska was produced with this added constraint. The multi-input contouring strategy allows production of a map with a regional interpretation of heat flow, in addition to site-specific heat flow and thermal model interpretations in areas with sufficient data density. Utilizing the new heat flow map, temperature-at-depth curves were created for example areas. Temperature-at-depth curves are calculated to 10 km depth for the areas of Anchorage, Fairbanks, Juneau, the Alaska Peninsula, Bristol Bay, and the Copper River Basin. The temperatures-at-depth predicted near the population centers of Anchorage and Juneau are relatively low, limiting the geothermal resource potential. The Fairbanks area temperature estimates are near conventional power production temperatures (150 °C) between 3.5 and 4 km. All data areas, except at Juneau, have temperatures sufficient for low temperature geothermal applications (40 °C) by 2 km. A high heat flow region exists within the Aleutian Volcanic Arc, although new data show heat flow variations from 59 to 120 mW m‑2, so individual geothermal resources within the arc will be irregularly located.

  3. Geodesic acoustic mode in anisotropic plasma with heat flux

    SciTech Connect

    Ren, Haijun

    2015-10-15

    Geodesic acoustic mode (GAM) in an anisotropic tokamak plasma is investigated in fluid approximation. The collisionless anisotropic plasma is described within the 16-momentum magnetohydrodynamic (MHD) fluid closure model, which takes into account not only the pressure anisotropy but also the anisotropic heat flux. It is shown that the GAM frequency agrees better with the kinetic result than the standard Chew-Goldberger-Low (CGL) MHD model. When zeroing the anisotropy, the 16-momentum result is identical with the kinetic one to the order of 1/q{sup 2}, while the CGL result agrees with the kinetic result only on the leading order. The discrepancies between the results of the CGL fluid model and the kinetic theory are well removed by considering the heat flux effect in the fluid approximation.

  4. Phase-controlled superconducting heat-flux quantum modulator

    NASA Astrophysics Data System (ADS)

    Giazotto, F.; Martínez-Pérez, M. J.

    2012-09-01

    We theoretically put forward the concept of a phase-controlled superconducting heat-flux quantum modulator. Its operation relies on phase-dependent heat current predicted to occur in temperature-biased Josephson tunnel junctions. The device behavior is investigated as a function of temperature bias across the junctions, bath temperature, and junctions asymmetry as well. In a realistic Al-based setup the structure could provide temperature modulation amplitudes up to ˜50 mK with flux-to-temperature transfer coefficients exceeding ˜125 mK/Φ0 below 1 K, and temperature modulation frequency of the order of a few MHz. The proposed structure appears as a promising building-block for the implementation of caloritronic devices operating at cryogenic temperatures.

  5. Method of fission heat flux determination from experimental data

    DOEpatents

    Paxton, Frank A.

    1999-01-01

    A method is provided for determining the fission heat flux of a prime specimen inserted into a specimen of a test reactor. A pair of thermocouple test specimens are positioned at the same level in the holder and a determination is made of various experimental data including the temperature of the thermocouple test specimens, the temperature of bulk water channels located in the test holder, the gamma scan count ratios for the thermocouple test specimens and the prime specimen, and the thicknesses of the outer clads, the fuel fillers, and the backclad of the thermocouple test specimen. Using this experimental data, the absolute value of the fission heat flux for the thermocouple test specimens and prime specimen can be calculated.

  6. A microscale thermophoretic turbine driven by external diffusive heat flux.

    PubMed

    Yang, Mingcheng; Liu, Rui; Ripoll, Marisol; Chen, Ke

    2014-11-21

    We propose a theoretical prototype of a micro-scale turbine externally driven by diffusive heat flux without the need for macroscopic particle flux, which is in sharp contrast to conventional turbines. The prototypes are described analytically and validated by computer simulations. Our results indicate that a micro-scale turbine composed of anisotropic blades can rotate unidirectionally in an external temperature gradient due to the anisotropic thermophoresis effect. The rotational direction and speed depend on the temperature gradient, the geometry and the thermophoretic properties of the turbine. The proposed thermophoretic turbines can be experimentally realized and implemented on micro-devices such as computer-chips to recover waste heat or to facilitate cooling.

  7. Mechanisms governing radial heat fluxes in tokamak plasma

    NASA Astrophysics Data System (ADS)

    Razumova, K. A.; Timchenko, N. N.; Dnestrovskij, A. Yu.; Lysenko, S. E.

    2016-09-01

    A method for analyzing the characteristics of turbulence responsible for radial heat transport is proposed. The method is based on the previously proposed hypotheses (to a great extent, confirmed experimentally) concerning the consistency of normalized pressure profiles in tokamak plasmas and the mechanism of internal transport barrier formation. Using the proposed approach, it is shown that, under an external action on the plasma, when the plasma heat flux onto the wall grows, the spectrum of turbulent modes broadens due to the excitation of modes with lower poloidal numbers m. Thus, in contrast to the conventional diffusion approach, the transport coefficient depends on the flux intensity. A mechanism of formation of internal transport barriers is proposed.

  8. A microscale thermophoretic turbine driven by external diffusive heat flux.

    PubMed

    Yang, Mingcheng; Liu, Rui; Ripoll, Marisol; Chen, Ke

    2014-11-21

    We propose a theoretical prototype of a micro-scale turbine externally driven by diffusive heat flux without the need for macroscopic particle flux, which is in sharp contrast to conventional turbines. The prototypes are described analytically and validated by computer simulations. Our results indicate that a micro-scale turbine composed of anisotropic blades can rotate unidirectionally in an external temperature gradient due to the anisotropic thermophoresis effect. The rotational direction and speed depend on the temperature gradient, the geometry and the thermophoretic properties of the turbine. The proposed thermophoretic turbines can be experimentally realized and implemented on micro-devices such as computer-chips to recover waste heat or to facilitate cooling. PMID:25268245

  9. Thermal ground-water discharge and associated convective heat flux, Bruneau-Grand View area, southwest Idaho

    USGS Publications Warehouse

    Young, H.W.; Lewis, R.E.; Backsen, R.L.

    1979-01-01

    The Bruneau-Grand View area occupies about 1,100 square miles in southwest Idaho. The area has a rural population dependent on ground-water irrigation. Temperature of the ground water ranges from 15 C to more than 80 C. Ground water for irrigation is obtained from flowing and pumped wells. Discharge of thermal ground water from 104 irrigation wells and from 5 hot springs in 1978 was about 50,500 acre-feet. Convective heat flux from the geothermal system associated with this discharge was 4.97 x 10 to the 7th power calories per second. (Woodard-USGS)

  10. Heat flow and hot dry rock geothermal resources of the Clearlake Region, northern California

    SciTech Connect

    Burns, K.L.

    1996-08-01

    The Geysers-Clear Lake geothermal anomaly is an area of high heat flow in northern California. The anomaly is caused by abnormally high heat flows generated by asthenospheric uplift and basaltic magmatic underplating at a slabless window created by passage of the Mendocino Triple Junction. The Clear Lake volcanic field is underlain by magmatic igneous bodies in the form of a stack of sill-form intrusions with silicic bodies generally at the top and basic magmas at the bottom. The tabular shape and wide areal extent of the heat sources results in linear temperature gradients and near-horizontal isotherms in a broad region at the center of the geothermal anomaly. The Hot Dry Rock (HDR) portion of The Geysers-Clear Lake geothermal field is that part of the geothermal anomaly that is external to the steamfield, bounded by geothermal gradients of 167 mW/m2 (4 heat flow units-hfu) and 335 mW/m2 (8 hfu). The HDR resources, to a depth of 5 km, were estimated by piece-wise linear summation based on a sketch map of the heat flow. Approximately, the geothermal {open_quotes}accessible resource base{close_quotes} (Qa) is 1.68E+21 J; the {open_quotes}HDR resource base{close_quotes} (Qha) is 1.39E+21 J; and the {open_quotes}HDR power production resource{close_quotes} (Qhp) is 1.01E+21 J. The HDR power production resource (Qhp) is equivalent to 2.78E+ 11 Mwht (megawatt hours thermal), or 1.72E+11 bbls of oil.

  11. A survey of geothermal process heat applications in Guatemala: An engineering survey

    SciTech Connect

    Altseimer, J.H.; Edeskuty, F.J.

    1988-08-01

    This study investigates how process heat from Guatemala's geothermal energy resources can be developed to reduce Guatemala's costly importation of oil, create new employment by encouraging new industry, and reduce fuel costs for existing industry. This investigation was funded by the US Agency for International Development and carried out jointly by the Guatemalan Government and the Los Alamos National Laboratory. Two sites, Amatitlan and Zunil, are being developed geothermally. Amatitlan is in the better industrial area but Zunil's geothermal development is more advanced. The industry around Zunil is almost exclusively agricultural and the development of an agricultural processing plant (freezing, dehydration, and cold storage) using geothermal heat is recommended. Similar developments throughout the volcanic zones of Guatemala are possible. Later, when the field at Amatitlan has been further developed, an industrial park can be planned. Potential Amatitlan applications are the final stage of salt refining, a thermal power plant, hospital/hotel heating and cooling, steam curing of concrete blocks, production of alcohol from sugar cane, and production of polyethylene from ethanol. Other special developments such as water pumping for the city of Guatemala and the use of moderate-temperature geothermal fluids for localized power production are also possible. 12 refs., 13 figs., 14 tabs.

  12. Geothermal direct-heat utilization assistance. Federal Assistance Program quarterly project progress report, April 1--June 30, 1998

    SciTech Connect

    1998-07-01

    This report summarizes geothermal technical assistance, R and D and technology transfer activities of the Geo-Heat Center at Oregon Institute of Technology for the third quarter of FY98 (April--June, 1998). It describes 231 contacts with parties during this period related to technical assistance with geothermal direct heat projects. Areas dealt with included requests for general information including material for high school and university students, and material on geothermal heat pumps, resource and well data, spacing heating and cooling, greenhouses, aquaculture, equipment, district heating, resorts and spas, industrial applications, snow melting and electric power. Research activities include work on model construction specifications for line shaft submersible pumps and plate heat exchangers, and a comprehensive aquaculture developers package. A brochure on Geothermal Energy in Klamath County was developed for state and local tourism use. Outreach activities include the publication of the Quarterly Bulletin (Vol. 19, No. 2) with articles on research at the Geo-Heat Center, sustainability of geothermal resources, injection well drilling in Boise, ID and a greenhouse project in the Azores. Other outreach activities include dissemination of information mainly through mailings of publications, tours of local geothermal uses, geothermal library acquisitions and use, participation in workshops, short courses and technical meetings by the staff, and progress monitor reports on geothermal activities.

  13. Heat flux instrumentation for HYFLITE thermal protection system

    NASA Technical Reports Server (NTRS)

    Diller, T. E.

    1994-01-01

    Tasks performed in this project were defined in a September 9, 1994 meeting of representatives of Vatell, NASA Lewis and Virginia Tech. The overall objective agreed upon in the meeting was 'to demonstrate the viability of thin film techniques for heat flux and temperature sensing in HYSTEP thermal protection systems'. We decided to attempt a combination of NASA's and Vatell's best heat flux sensor technology in a sensor which would be tested in the Vortek facility at Lewis early in 1995. The NASA concept for thermocouple measurement of surface temperature was adopted, and Vatell methods for fabrication of sensors on small diameter substrates of aluminum nitride were used to produce a sensor. This sensor was then encapsulated in a NARloy-Z housing. Various improvements to the Vatell substrate design were explored without success. The basic NASA and Vatell sensor layouts were analyzed by finite element modeling, in an attempt to better understand the effects of material properties, dimensions and thermal differential element location on sensor symmetry, bandwidth and sensitivity. This analysis showed that, as long as the thermal resistivity of the thermal differential element material is much larger (10X) than that of the substrate material, the simplest arrangement of layer is best. During calibration of the sensor produced in this project, undesirable side-effects of combining the heat flux and temperature sensor return leads were observed. The sensor did not cleanly separate the heat flux and temperature signals, as sensors with four leads have consistently done before. Task 7 and 8 discussed in the meeting will be performed with a continuation of funding in 1995. The following is a discussion of each of the tasks performed as outlined in the statement of work dated september 26, 1994. Task 1A was added to cover further investigation into the NASA sensor concept.

  14. Development of advanced high-temperature heat flux sensors

    NASA Technical Reports Server (NTRS)

    Atkinson, W. H.; Strange, R. R.

    1982-01-01

    Various configurations of high temperature, heat flux sensors were studied to determine their suitability for use in experimental combustor liners of advanced aircraft gas turbine engines. It was determined that embedded thermocouple sensors, laminated sensors, and Gardon gauge sensors, were the most viable candidates. Sensors of all three types were fabricated, calibrated, and endurance tested. All three types of sensors met the fabricability survivability, and accuracy requirements established for their application.

  15. Dual Nature of Heat Flux in Stable Atmospheric Surface Layer

    NASA Astrophysics Data System (ADS)

    Srivastava, P.; Sharan, M.

    2015-12-01

    The behavior of heat flux (H) with respect to the stability parameter (ζ) in stable surface layer (SSL) is analyzed with in the framework of Monin-Obukhov similarity (MOS) theory. The analytical expressions of H are obtained as functions of wind speed (U) and wind shear (dU/dz) using the linear similarity functions and accordingly two cases, (i) U = δ (constant) and (ii) dU/dz = δ are considered. The mathematical analysis shows that the magnitude of H increases with ζ till it attains a maximum value at ζ =ζc and then starts decreasing with increasing stability suggesting the dual characteristic of heat flux with stability parameter. The point of maximum heat flux is found to be dependent on the roughness length (z0) as well as the height above the surface. An attempt has been made to analyze the sensitivity of this dual characteristic of H with ζ using the non-linear similarity functions. The analysis shows that the dual nature of H persists in the case of linear as well as non-linear similarity functions. However, the point of extremum appears to be dependent on the nature of the similarity functions. Turbulent data over a tropical site Ranchi (India) is analyzed to validate the observed nature of H with the theoretical nature as predicted by MOS. The analysis of observational data reveals the non-existence of any preferred stability state in SSL as speculated by Wang and Bras (2010, 2011) and supports the conclusions of Malhi 1995, Derbyshire 1999, van de Wiel et al. 2007, Basu et al. 2008, and van de Wiel et al. 2011. Thus, the non-uniqueness of MOS equations does not appear to be a mathematical artifact and it is consistent with the observations as far as the nature of heat flux with respect to stability parameter in SSL is concerned.

  16. Supercritical heat exchanger field test (SHEFT), I. Field performance data on shell-and-tube heat exchangers in geothermal service

    SciTech Connect

    Silvester, L.F.; Beaulaurier, L.O.; Mirk, K.F.; Fulton, R.L.

    1981-06-01

    Field performance data on shell-and-tube heat exchangers in geothermal service are presented. The test data were taken for geothermal brine on the tube side and hydrocarbon on the shell side in counterflow for six primary heat exchangers, and for hydrocarbon on the shell side and cooling water on the tube side for the condenser. Test data were for heating isobutane, 1 90/10 isobutane/isopentane mixture, and a 80/20 isobutane/isopentane mixture at supercritical conditions in the vicinity of their critical pressure and temperature, and for condensing the same fluids. The test data were used in a preliminary data analysis to determine the reported heat exchanger performance parameters.

  17. Applications of fractured continuum model to enhanced geothermal system heat extraction problems.

    PubMed

    Kalinina, Elena A; Klise, Katherine A; McKenna, Sean A; Hadgu, Teklu; Lowry, Thomas S

    2014-01-01

    This paper describes the applications of the fractured continuum model to the different enhanced geothermal systems reservoir conditions. The capability of the fractured continuum model to generate fracture characteristics expected in enhanced geothermal systems reservoir environments are demonstrated for single and multiple sets of fractures. Fracture characteristics are defined by fracture strike, dip, spacing, and aperture. The paper demonstrates how the fractured continuum model can be extended to represent continuous fractured features, such as long fractures, and the conditions in which the fracture density varies within the different depth intervals. Simulations of heat transport using different fracture settings were compared with regard to their heat extraction effectiveness. The best heat extraction was obtained in the case when fractures were horizontal. A conventional heat extraction scheme with vertical wells was compared to an alternative scheme with horizontal wells. The heat extraction with the horizontal wells was significantly better than with the vertical wells when the injector was at the bottom.

  18. Effect of heat flux on differential rotation in turbulent convection.

    PubMed

    Kleeorin, Nathan; Rogachevskii, Igor

    2006-04-01

    We studied the effect of the turbulent heat flux on the Reynolds stresses in a rotating turbulent convection. To this end we solved a coupled system of dynamical equations which includes the equations for the Reynolds stresses, the entropy fluctuations, and the turbulent heat flux. We used a spectral tau approximation in order to close the system of dynamical equations. We found that the ratio of the contributions to the Reynolds stresses caused by the turbulent heat flux and the anisotropic eddy viscosity is of the order of approximately 10(L rho/l0)2, where l0 is the maximum scale of turbulent motions and L rho is the fluid density variation scale. This effect is crucial for the formation of the differential rotation and should be taken into account in the theories of the differential rotation of the Sun, stars, and planets. In particular, we demonstrated that this effect may cause the differential rotation which is comparable with the typical solar differential rotation.

  19. Laboratory experiments of heat and moisture fluxes through supraglacial debris

    NASA Astrophysics Data System (ADS)

    Nicholson, Lindsey; Mayer, Christoph; Wirbel, Anna

    2014-05-01

    Inspired by earlier work (Reznichenko et al., 2010), we have carried out experiments within a climate chamber to explore the best ways to measure the heat and moisture fluxes through supraglacial debris. Sample ice blocks were prepared with debris cover of varying lithology, grain size and thickness and were instrumented with a combination of Gemini TinyTag temperature/relative humidity sensors and Decagon soil moisture sensors in order to monitor the heat and moisture fluxes through the overlying debris material when the experiment is exposed to specified solar lamp radiation and laminar airflow within the temperature-controlled climate chamber. Experimental results can be used to determine the optimal set up for numerical models of heat and moisture flux through supraglacial debris and also indicate the performance limitations of such sensors that can be expected in field installations. Reznichenko, N., Davies, T., Shulmeister, J. and McSaveney, M. (2010) Effects of debris on ice-surface melting rates: an experimental study. Journal of Glaciology, Volume 56, Number 197, 384-394.

  20. Spray cooling heat-transfer with subcooled trichlorotrifluoroethane (Freon-113) for vertical constant heat flux surfaces

    SciTech Connect

    Kendall, C.M.; Holman, J.P.

    1996-06-06

    Experiments were done using subcooled Freon-113 sprayed vertically downward. Local and average heat transfers were investigated fro Freon-113 sprays with 40 C subcooling, droplet sizes 200-1250{mu}m, and droplet breakup velocities 5-29 m/s. Full-cone type nozzles were used to generate the spray. Test assemblies consisted of 1 to 6 7.62 cm vertical constant heat flux surfaces parallel with each other and aligned horizontally. Distance between heated surfaces was varied from 6.35 to 76.2 mm. Steady state heat fluxes as high as 13 W/cm{sup 2} were achieved. Dependence on the surface distance from axial centerline of the spray was found. For surfaces sufficiently removed from centerline, local and average heat transfers were identical and correlated by a power relation of the form seen for normal-impact sprays which involves the Weber number, a nondimensionalized temperature difference, and a mass flux parameter. For surfaces closer to centerline, the local heat transfer depended on vertical location on the surface while the average heat transfer was described by a semi-log correlation involving the same parameters. The heat transfer was independent of the distance (gap) between the heated surfaces for the gaps investigated.

  1. Local Heat Flux Measurements with Single Element Coaxial Injectors

    NASA Technical Reports Server (NTRS)

    Jones, Gregg; Protz, Christopher; Bullard, Brad; Hulka, James

    2006-01-01

    To support the mission for the NASA Vision for Space Exploration, the NASA Marshall Space Flight Center conducted a program in 2005 to improve the capability to predict local thermal compatibility and heat transfer in liquid propellant rocket engine combustion devices. The ultimate objective was to predict and hence reduce the local peak heat flux due to injector design, resulting in a significant improvement in overall engine reliability and durability. Such analyses are applicable to combustion devices in booster, upper stage, and in-space engines, as well as for small thrusters with few elements in the injector. In this program, single element and three-element injectors were hot-fire tested with liquid oxygen and ambient temperature gaseous hydrogen propellants at The Pennsylvania State University Cryogenic Combustor Laboratory from May to August 2005. Local heat fluxes were measured in a 1-inch internal diameter heat sink combustion chamber using Medtherm coaxial thermocouples and Gardon heat flux gauges. Injectors were tested with shear coaxial and swirl coaxial elements, including recessed, flush and scarfed oxidizer post configurations, and concentric and non-concentric fuel annuli. This paper includes general descriptions of the experimental hardware, instrumentation, and results of the hot-fire testing for three of the single element injectors - recessed-post shear coaxial with concentric fuel, flush-post swirl coaxial with concentric fuel, and scarfed-post swirl coaxial with concentric fuel. Detailed geometry and test results will be published elsewhere to provide well-defined data sets for injector development and model validatation.

  2. Observational & modeling analysis of surface heat and moisture fluxes

    SciTech Connect

    Smith, E.

    1995-09-01

    An observational and modeling study was conducted to help assess how well current GCMs are predicting surface fluxes under the highly variable cloudiness and flow conditions characteristic of the real atmosphere. The observational data base for the study was obtained from a network of surface flux stations operated during the First ISLSCP Field Experiment (FIFE). The study included examination of a surface-driven secondary circulation in the boundary layer resulting from a persistent cross-site gradient in soil moisture, to demonstrate the sensitivity of boundary layer dynamics to heterogeneous surface fluxes, The performance of a biosphere model in reproducing the measured surface fluxes was evaluated with and without the use of satellite retrieval of three key canopy variables with RMS uncertainties commensurate with those of the measurements themselves. Four sensible heat flux closure schemes currently being used in GCMs were then evaluated against the FIFE observations. Results indicate that the methods by which closure models are calibrated lead to exceedingly large errors when the schemes are applied to variable boundary layer conditions. 4 refs., 2 figs.

  3. Preliminary direct heat geothermal resource assessment of the Tennessee Valley region

    SciTech Connect

    Staub, W.P.

    1980-01-01

    A preliminary appraisal of the direct heat geothermal energy resources of the Tennessee Valley region has been completed. This region includes Kentucky, Tennessee and parts of adjacent states. Intermediate and deep aquifers were selected for study. Basement and Top-of-Knox structure and temperature maps were compiled from oil and gas well data on file at various state geological survey offices. Results of this study indicate that the New Madrid seismic zone is the only area within the region that possesses potential for direct heat utilization. In other areas geothermal energy is either too deep for economical extraction or it will not be able to compete with other local energy resources. The only anomalously high temperature well outside the New Madrid seismic zone was located in the Rome Trough and near the central part of the eastern Kentucky coal basin. Geothermal energy in that region would face strong competition from coal, oil and natural gas.

  4. Spatial and Temporal Changes to Water Chemistry and Heat Flux of the Lake Rotomahana Hydrothermal System

    NASA Astrophysics Data System (ADS)

    Stucker, V. K.; Tivey, M.; Lupton, J. E.; Walker, S. L.; Fornari, D. J.; de Ronde, C. E. J.

    2014-12-01

    Lake Rotomahana (North Island, New Zealand) is a crater lake with prominent hydrothermal venting. Water column studies were conducted in 2011 and 2014 to complement magnetic, seismic, bathymetric and heat flux surveys, respectively. Results from the heat flow survey indicate that Lake Rotomahana is getting warmer relative to historic measurements, with individual stations within the lake releasing heat in excess of 60 Watts/m2. Helium sources are found at the lake floor at depths of ~50 meters and ~100m. Helium concentrations below 50 m depth have increased with high statistical significance over the three years between surveys and represent some of the highest concentrations ever measured at 6x107 ccSTP/g with an end-member 3He/4He value of 7.1 Ra. Hydrothermal activity comprises a significant portion of the inputs to Lake Rotomahana, as evidenced by δD and δ18O values, as well as ratios of conservative elements such as boron and chloride. Waters collected from lakeshore hot springs show geographic differences in geothermal source temperature using a Na-K geothermometer, with inferred reservoir temperatures ranging from 200 to 230°C. Lake Rotomahana was in part the focus of the 1886 Tarawera eruption; our results show both pre-eruption hydrothermal sites and newly created post-eruption sites are active and should be monitored for continued changes.

  5. Critical heat flux maxima during boiling crisis on textured surfaces

    PubMed Central

    Dhillon, Navdeep Singh; Buongiorno, Jacopo; Varanasi, Kripa K.

    2015-01-01

    Enhancing the critical heat flux (CHF) of industrial boilers by surface texturing can lead to substantial energy savings and global reduction in greenhouse gas emissions, but fundamentally this phenomenon is not well understood. Prior studies on boiling crisis indicate that CHF monotonically increases with increasing texture density. Here we report on the existence of maxima in CHF enhancement at intermediate texture density using measurements on parametrically designed plain and nano-textured micropillar surfaces. Using high-speed optical and infrared imaging, we study the dynamics of dry spot heating and rewetting phenomena and reveal that the dry spot heating timescale is of the same order as that of the gravity and liquid imbibition-induced dry spot rewetting timescale. Based on these insights, we develop a coupled thermal-hydraulic model that relates CHF enhancement to rewetting of a hot dry spot on the boiling surface, thereby revealing the mechanism governing the hitherto unknown CHF enhancement maxima. PMID:26346098

  6. Critical heat flux maxima during boiling crisis on textured surfaces.

    PubMed

    Dhillon, Navdeep Singh; Buongiorno, Jacopo; Varanasi, Kripa K

    2015-01-01

    Enhancing the critical heat flux (CHF) of industrial boilers by surface texturing can lead to substantial energy savings and global reduction in greenhouse gas emissions, but fundamentally this phenomenon is not well understood. Prior studies on boiling crisis indicate that CHF monotonically increases with increasing texture density. Here we report on the existence of maxima in CHF enhancement at intermediate texture density using measurements on parametrically designed plain and nano-textured micropillar surfaces. Using high-speed optical and infrared imaging, we study the dynamics of dry spot heating and rewetting phenomena and reveal that the dry spot heating timescale is of the same order as that of the gravity and liquid imbibition-induced dry spot rewetting timescale. Based on these insights, we develop a coupled thermal-hydraulic model that relates CHF enhancement to rewetting of a hot dry spot on the boiling surface, thereby revealing the mechanism governing the hitherto unknown CHF enhancement maxima. PMID:26346098

  7. THERMALLY CONDUCTIVE CEMENTITIOUS GROUTS FOR GEOTHERMAL HEAT PUMPS. PROGRESS REPORT BY 1998

    SciTech Connect

    ALLAN,M.L.; PHILIPPACOPOULOS,A.J.

    1998-11-01

    Research commenced in FY 97 to determine the suitability of superplasticized cement-sand grouts for backfilling vertical boreholes used with geothermal heat pump (GHP) systems. The overall objectives were to develop, evaluate and demonstrate cementitious grouts that could reduce the required bore length and improve the performance of GHPs. This report summarizes the accomplishments in FY 98.

  8. Geothermal potential for heating and cooling facilities, San Bernardino Valley College, San Bernardino, California

    SciTech Connect

    Gemeinhardt, M.A.; Tharaldson, L.C.

    1981-07-01

    The potential for converting to geothermal heating at the campus of San Bernardino Valley College is considered. Also considered is the possibility of using well water for water cooled condenser cooling of air conditioning equipment. To provide water supply a production well, water distribution system and an injection well would be installed for each system.

  9. Direct-use geothermal district heating projects in the US. A summary

    SciTech Connect

    Fornes, A.O.

    1981-10-01

    Brief summaries of geothermal district heating projects are presented for the following: Boise, Idaho; Elko, Nevada; Ephrata, Washington; Hawthorne, Nevada; Klamath Falls, Oregon; Lakeview, Oregon; Madison County, Idaho; North Bonneville, Washington; Pagosa Springs, Colorado; Preston, Idaho; Reno, Nevada; Susanville, California; Thermopolis, Wyoming; and Utah State Prison, Utah. (MHR)

  10. Evaluation of geothermal energy as a heat source for the oilsands industry in Northern Alberta (Canada)

    NASA Astrophysics Data System (ADS)

    Majorowicz, J. A.; Unsworth, M.; Gray, A.; Nieuwenhuis, G.; Babadagli, T.; Walsh, N.; Weides, S.; Verveda, R.

    2012-12-01

    The extraction and processing of bitumen from the oilsands of Northern Alberta requires very large amounts of heat that is obtained by burning natural gas. At current levels, the gas used represents 6% of Canada's natural gas production. Geothermal energy could potentially provide this heat, thereby reducing both the financial costs and environmental impact of the oilsands industry. The Helmholtz Alberta Initiative is evaluating this application of geothermal energy through an integrated program of geology, geophysics, reservoir simulation and calculations of the cost benefit. A first stage in this evaluation is refining estimates of subsurface temperature beneath Northern Alberta. This has involved three stages: (1) Corrected industrial thermal data have been used to revise estimates of the upper crustal temperatures beneath the oilsands regions in Alberta. The geothermal gradient map produced using heat flow and thermal conductivity for the entire Phanerozoic column suggests that the overall gradient of the entire column is less than the gradients calculated directly from industry measurements. (2) Paleoclimatic corrections must be applied , since this region has experienced a significant increase in surface temperatures since the end of the last ice age causing a perturbation of shallow heat flow. For this reason, estimates of geothermal gradient based on shallow data are not necessarily characteristic of the whole sedimentary column and can lead to errors in temperature prediction at depth. (3) Improved measurements have been made of the thermal conductivity of the crystalline basement rocks (average = 2.9±0.8 W/m K). Thermal conductivity exhibits significant spatial variability and to a large degree controls the temperature conditions in the Precambrian crystalline basement rocks and its heat content at given heat flow-heat generation. When these steps are used to calculate subsurface temperatures, it can be shown that the temperatures required for geothermal

  11. Calculation of heating values for the high flux isotope reactor

    SciTech Connect

    Peterson, J.; Ilas, G.

    2012-07-01

    Calculating the amount of energy released by a fission reaction (fission Q value) and the heating rate distribution in a nuclear reactor is an important part of the safety analysis. However, these calculations can become very complex. One of the codes that can be used for this type of analyses is the Monte Carlo transport code MCNP5. Currently it is impossible to calculate the Q value and heating rate disposition for delayed beta and delayed gamma particles directly from MCNP5. The purpose of this paper is to outline a rigorous method for indirectly calculating the Q values and heating rates in the High Flux Isotope Reactor (HFIR), based on previous similar studies carried out for very high-temperature reactor configurations. This method has been applied in this study to calculate heating rates for the beginning of cycle (BOC) and end-of-cycle (EOC) states of HFIR. In addition, the BOC results obtained for HFIR are compared with corresponding results for the Advanced Test Reactor. The fission Q value for HFIR was calculated as 200.2 MeV for the BOC and 201.3 MeV for the EOC. It was also determined that 95.1% and 95.4% of the heat was deposited within the HFIR fuel plates for the BOC and EOC models, respectively. This methodology can also be used for heating rate calculations for HFIR experiments. (authors)

  12. Calculation of Heating Values for the High Flux Isotope Reactor

    SciTech Connect

    Peterson, Joshua L; Ilas, Germina

    2012-01-01

    Calculating the amount of energy released by a fission reaction (fission Q value) and the heating rate distribution in a nuclear reactor is an important part of the safety analysis. However, these calculations can become very complex. One of the codes that can be used for this type of analyses is the Monte Carlo transport code MCNP5. Currently it is impossible to calculate the Q value and heating rate disposition for delayed beta and delayed gamma particles directly from MCNP5. The purpose of this paper is to outline a rigorous method for indirectly calculating the Q values and heating rates in the High Flux Isotope Reactor (HFIR), based on previous similar studies carried out for very high-temperature reactor configurations. This method has been applied in this study to calculate heating rates for the beginning of cycle (BOC) and end-of-cycle (EOC) states of HFIR. In addition, the BOC results obtained for HFIR are compared with corresponding results for the Advanced Test Reactor. The fission Q value for HFIR was calculated as 200.2 MeV for the BOC and 201.3 MeV for the EOC. It was also determined that 95.1% and 95.4% of the heat was deposited within the HFIR fuel plates for the BOC and EOC models, respectively. This methodology can also be used for heating rate calculations for HFIR experiments.

  13. Geothermal potential for commercial and industrial direct heat applications in Salida, Colorado. Final report

    SciTech Connect

    Coe, B.A.; Dick, J.D.; Galloway, M.J.; Gross, J.T.; Meyer, R.T.; Raskin, R.; Zocholl, J.R.

    1982-10-01

    The Salida Geothermal Prospect (Poncha Hot Springs) was evaluated for industrial and commercial direct heat applications at Salida, Colorado, which is located approximately five miles east of Poncha Hot Springs. Chaffee Geothermal, Ltd., holds the geothermal leases on the prospect and the right-of-way for the main pipeline to Salida. The Poncha Hot Springs are located at the intersection of two major structural trends, immediately between the Upper Arkansas graben and the Sangre de Cristo uplift. Prominent east-west faulting occurs at the actual location of the hot springs. Preliminary exploration indicates that 1600 gpm of geothermal fluid as hot as 250/sup 0/F is likely to be found at around 1500 feet in depth. The prospective existing endusers were estimated to require 5.02 x 10/sup 10/ Btu per year, but the total annual amount of geothermal energy available for existing and future endusers is 28.14 x 10/sup 10/ Btu. The engineering design for the study assumed that the 1600 gpm would be fully utilized. Some users would be cascaded and the spent fluid would be cooled and discharged to nearby rivers. The economic analysis assumes that two separate businesses, the energy producer and the energy distributor, are participants in the geothermal project. The producer would be an existing limited partnership, with Chaffee Geothermal, Ltd. as one of the partners; the distributor would be a new Colorado corporation without additional income sources. Economic evaluations were performed in full for four cases: the Base Case and three alternate scenarios. Alternate 1 assumes a three-year delay in realizing full production relative to the Base Case; Alternate 2 assumes that the geothermal reservoir is of a higher quality than is assumed for the Base Case; and Alternate 3 assumes a lower quality reservoir. 11 refs., 34 figs., 40 tabs.

  14. Solar Flux Deposition And Heating Rates In Jupiter's Atmosphere

    NASA Astrophysics Data System (ADS)

    Perez-Hoyos, Santiago; Sánchez-Lavega, A.

    2009-09-01

    We discuss here the solar downward net flux in the 0.25 - 2.5 µm range in the atmosphere of Jupiter and the associated heating rates under a number of vertical cloud structure scenarios focusing in the effect of clouds and hazes. Our numerical model is based in the doubling-adding technique to solve the radiative transfer equation and it includes gas absorption by CH4, NH3 and H2, in addition to Rayleigh scattering by a mixture of H2 plus He. Four paradigmatic Jovian regions have been considered (hot-spots, belts, zones and Polar Regions). The hot-spots are the most transparent regions with downward net fluxes of 2.5±0.5 Wm-2 at the 6 bar level. The maximum solar heating is 0.04±0.01 K/day and occurs above 1 bar. Belts and zones characterization result in a maximum net downward flux of 0.5 Wm-2 at 2 bar and 0.015 Wm-2 at 6 bar. Heating is concentrated in the stratospheric and tropospheric hazes. Finally, Polar Regions are also explored and the results point to a considerable stratospheric heating of 0.04±0.02 K/day. In all, these calculations suggest that the role of the direct solar forcing in the Jovian atmospheric dynamics is limited to the upper 1 - 2 bar of the atmosphere except in the hot-spot areas. Acknowledgments: This work has been funded by Spanish MEC AYA2006-07735 with FEDER support and Grupos Gobierno Vasco IT-464-07.

  15. Boundary layer structure over areas of heterogeneous heat fluxes

    SciTech Connect

    Doran, J.C.; Barnes, F.J.; Coulter, R.L.; Crawford, T.L.

    1993-04-01

    In general circulation models (GCMs), some properties of a grid element are necessarily considered homogeneous. That is, for each grid volume there is associated a particular combination of boundary layer depth, vertical profiles of wind and temperature, surface fluxes of sensible and latent heat, etc. In reality, all of these quantities may exhibit significant spatial variations within the grid area, and the larger the area the greater the likely variations. In balancing the benefits of higher resolution against increased computational time and expense, it is useful to consider what the consequences of such subgrid-scale variability may be. Moveover, in interpreting the results of a simulation, one must be able to define an appropriate average value over a grid. There are two aspects of this latter problem: (1) in observations, how does one take a set of discrete or volume-averaged measurements and relate these to properties of the entire domain, and (2) in computations, how can subgrid-scale features be accounted for in the model parameterizations? To address these and related issues, two field campaigns were carried out near Boardman, Oregon, in June 1991 and 1992. These campaigns were designed to measure the surface fluxes of latent and sensible heat over adjacent areas with strongly contrasting surface types and to measure the response of the boundary layer to those fluxes. This paper discuses some initial findings from those campaigns.

  16. Boundary layer structure over areas of heterogeneous heat fluxes

    SciTech Connect

    Doran, J.C.; Barnes, F.J.; Coulter, R.L.; Crawford, T.L.

    1993-01-01

    In general circulation models (GCMs), some properties of a grid element are necessarily considered homogeneous. That is, for each grid volume there is associated a particular combination of boundary layer depth, vertical profiles of wind and temperature, surface fluxes of sensible and latent heat, etc. In reality, all of these quantities may exhibit significant spatial variations the grid area, and the larger the area the greater the likely variations. In balancing the benefits of higher resolution against increased computational time and expense, it is useful to consider what the consequences of such subgrid-scale variability may be. Moreover, in interpreting the results of a simulation, one must be able to define an appropriate average value over a grid. There are two aspects of this latter problem: (1) in observations, how does one take a set of discrete or volume-averaged measurements and relate these to properties of the entire domain, and (2) in computations, how can subgrid-scale features be accounted for in the model parameterizations? To address these and related issues, two field campaigns were carried out near Boardman, Oregon, in June 1991 and 1992. These campaigns were designed to measure the surface fluxes of latent and sensible heat over adjacent areas with strongly contrasting surface types and to measure the response of the boundary layer to those fluxes. This paper discusses some initial findings from those campaigns.

  17. Boundary layer structure over areas of heterogeneous heat fluxes

    SciTech Connect

    Doran, J.C. ); Barnes, F.J. ); Coulter, R.L. ); Crawford, T.L. . Air Resources Lab. Atmospheric Turbulence and Diffusion Div.)

    1993-01-01

    In general circulation models (GCMs), some properties of a grid element are necessarily considered homogeneous. That is, for each grid volume there is associated a particular combination of boundary layer depth, vertical profiles of wind and temperature, surface fluxes of sensible and latent heat, etc. In reality, all of these quantities may exhibit significant spatial variations within the grid area, and the larger the area the greater the likely variations. In balancing the benefits of higher resolution against increased computational time and expense, it is useful to consider what the consequences of such subgrid-scale variability may be. Moveover, in interpreting the results of a simulation, one must be able to define an appropriate average value over a grid. There are two aspects of this latter problem: (1) in observations, how does one take a set of discrete or volume-averaged measurements and relate these to properties of the entire domain, and (2) in computations, how can subgrid-scale features be accounted for in the model parameterizations To address these and related issues, two field campaigns were carried out near Boardman, Oregon, in June 1991 and 1992. These campaigns were designed to measure the surface fluxes of latent and sensible heat over adjacent areas with strongly contrasting surface types and to measure the response of the boundary layer to those fluxes. This paper discuses some initial findings from those campaigns.

  18. Boundary layer structure over areas of heterogeneous heat fluxes

    SciTech Connect

    Doran, J.C. ); Barnes, F.J. ); Coulter, R.L. ); Crawford, T.L. . Air Resources Lab. Atmospheric Turbulence and Diffusion Div.)

    1993-01-01

    In general circulation models (GCMs), some properties of a grid element are necessarily considered homogeneous. That is, for each grid volume there is associated a particular combination of boundary layer depth, vertical profiles of wind and temperature, surface fluxes of sensible and latent heat, etc. In reality, all of these quantities may exhibit significant spatial variations the grid area, and the larger the area the greater the likely variations. In balancing the benefits of higher resolution against increased computational time and expense, it is useful to consider what the consequences of such subgrid-scale variability may be. Moreover, in interpreting the results of a simulation, one must be able to define an appropriate average value over a grid. There are two aspects of this latter problem: (1) in observations, how does one take a set of discrete or volume-averaged measurements and relate these to properties of the entire domain, and (2) in computations, how can subgrid-scale features be accounted for in the model parameterizations To address these and related issues, two field campaigns were carried out near Boardman, Oregon, in June 1991 and 1992. These campaigns were designed to measure the surface fluxes of latent and sensible heat over adjacent areas with strongly contrasting surface types and to measure the response of the boundary layer to those fluxes. This paper discusses some initial findings from those campaigns.

  19. New technique of the local heat flux measurement in combustion chambers of steam boilers

    NASA Astrophysics Data System (ADS)

    Taler, Jan; Taler, Dawid; Sobota, Tomasz; Dzierwa, Piotr

    2011-12-01

    A new method for measurement of local heat flux to water-walls of steam boilers was developed. A flux meter tube was made from an eccentric tube of short length to which two longitudinal fins were attached. These two fins prevent the boiler setting from heating by a thermal radiation from the combustion chamber. The fins are not welded to the adjacent water-wall tubes, so that the temperature distribution in the heat flux meter is not influenced by neighbouring water-wall tubes. The thickness of the heat flux tube wall is larger on the fireside to obtain a greater distance between the thermocouples located inside the wall which increases the accuracy of heat flux determination. Based on the temperature measurements at selected points inside the heat flux meter, the heat flux absorbed by the water-wall, heat transfer coefficient on the inner tube surface and temperature of the water-steam mixture was determined.

  20. A hybrid geothermal energy conversion technology: Auxiliary heating of geothermally preheated water or CO2 - a potential solution for low-temperature resources

    NASA Astrophysics Data System (ADS)

    Saar, Martin; Garapati, Nagasree; Adams, Benjamin; Randolph, Jimmy; Kuehn, Thomas

    2016-04-01

    Safe, sustainable, and economic development of deep geothermal resources, particularly in less favourable regions, often requires employment of unconventional geothermal energy extraction and utilization methods. Often "unconventional geothermal methods" is synonymously and solely used as meaning enhanced geothermal systems, where the permeability of hot, dry rock with naturally low permeability at greater depths (4-6 km), is enhanced. Here we present an alternative unconventional geothermal energy utilization approach that uses low-temperature regions that are shallower, thereby drastically reducing drilling costs. While not a pure geothermal energy system, this hybrid approach may enable utilization of geothermal energy in many regions worldwide that can otherwise not be used for geothermal electricity generation, thereby increasing the global geothermal resource base. Moreover, in some realizations of this hybrid approach that generate carbon dioxide (CO2), the technology may be combined with carbon dioxide capture and storage (CCS) and CO2-based geothermal energy utilization, resulting in a high-efficiency (hybrid) geothermal power plant with a negative carbon footprint. Typically, low- to moderate-temperature geothermal resources are more effectively used for direct heat energy applications. However, due to high thermal losses during transport, direct use requires that the heat resource is located near the user. Alternatively, we show here that if such a low-temperature geothermal resource is combined with an additional or secondary energy resource, the power production is increased compared to the sum from two separate (geothermal and secondary fuel) power plants (DiPippo et al. 1978) and the thermal losses are minimized because the thermal energy is utilized where it is produced. Since Adams et al. (2015) found that using CO2 as a subsurface working fluid produces more net power than brine at low- to moderate-temperature geothermal resource conditions, we

  1. Particle and heat flux measurements in PDX edge plasmas

    SciTech Connect

    Budny, R.; Manos, D.

    1983-12-01

    This paper describes the use of novel combined Langmuir-calorimeter probes to measure edge plasma conditions near the midplane in PDX. The probes consisted of up to five Langmuir probes and up to two calorimeters. Single and double probe characteristics yield n/sub e/ and T/sub e/ which are compared with that derived from a triple probe analysis. The calorimeters measure heat flux in the electron and ion drift directions. This paper presents time-resolved radial profiles of n/sub e/, T/sub e/, V/sub F/ (floating potential), and P (heat flux) during high power neutral beam-heated, single-null discharges and circular scoop limiter discharges. The temporal dependence of these quantities displays the previous observed behavior with respect to gross discharge characteristics; however, an additional dependence on confinement mode has been observed. During the H-mode of energy confinement, a transient depression of n/sub e/, T/sub e/, and P occurs in the scrape-off plasma.

  2. Geochemical properties of groundwater used to geothermal cooling and heating system

    NASA Astrophysics Data System (ADS)

    Kim, Namju; Park, Youngyun; Lee, Jin-Yong

    2013-04-01

    Recently, geothermal cooling and heating system has been used in many countries to reduce emission of greenhouse gases such as water vapour and carbon dioxide (CO2). Especially, CO2 is emitted from combustion of fossil fuel used for cooling and heating of buildings. Therefore, many countries make an effort to reduce amount of CO2 emitted from use of fossil fuel. The geothermal cooling and heating system is good to reduce amount of CO2. Especially, open loop geothermal system shows good thermal efficiency. However, groundwater contaminations will be considered because groundwater is directly used in open loop geothermal system. This study was performed to examine chemical and isotope compositions of groundwater used in open loop geothermal system and to evaluate influence of the system on groundwater using hydrochemical modeling program (preequc). Water temperature of well used in the system (GH) and well around the system (GB) ranged from 8.4 to 17.0 ° and from 15.1 to 18.0 °, respectively. The water temperature in GH was lower than that in GB because of heating mode of the system. Also, EC in GH and GB showed significant difference. The variation trend of EC was different at each site where the system was installed. These results mean that main factors controlling EC in GH was not the system. Generally, EC of groundwater was influenced by water-rock interaction. However, DO and Eh hardly showed significant difference. The operation period of the system observed in this study was short than 5 years. Therefore, influence of the open loop geothermal system on groundwater did not shown significantly. However, while Fe2+ and Mn2+ were not observed in GB, these components were measured in GH. The concentrations of Fe2+ and Mn2+ in GH ranged from 0.02 to 0.14 mg/L and from 0.03 to 0.18 mg/L, respectively. These results mean that redox conditions of GH were changed by the system little by little. In this study, influence of the open loop geothermal system on groundwater

  3. Generic model for district heating: a geothermal appliance

    SciTech Connect

    Reisman, A.

    1980-11-01

    Brookhaven National Laboratory (BNL) is developing a model desgined to assess the engineering and economic requirements which must be addressed when the implementation of district heating is seriously considered. A brief overview of the structure of the BNL District Heating Model is presented, including a discussion of the function of each of its major program components. The model is composed of four submodels, each of which serves a distinct function in the analysis of district heating. These are the Heat Demand, Heat Source, District Heating, and Market analysis Submodels. (MHR)

  4. On the relation between coronal heating, flux tube divergence, and the solar wind proton flux and flow speed

    NASA Technical Reports Server (NTRS)

    Sandbaek, Onulf; Leer, Egil; Hansteen, Viggo H.

    1994-01-01

    A one-fluid solar wind model is used to investigate some relations between coronal heating, the flux tube divergence near the Sun, and the solar wind proton flux and flow speed. The effects of energy addition to the supersonic region of the flow are also studied. We allow for a mechanical energy flux that heats the corona, and an Alfven wave energy flux that adds energy, mainly to the supersonic flow, both as momentum and as heat. We find that the mechanical energy flux determines the solar wind mass flux, and in order to keep an almost constant proton flux at the orbit of Earth with changing flow geometry, that the mechanical energy flux must vary linearly with the magnetic field in the inner corona. This thermally driven wind generally has a low asymptotic flow speed. When Alfven waves are added to the thermally driven flow, the asymptotic flow speed is increased and is determined by the ratio of the Alfven wave and the mechanical energy fluxes at the coronal base. Flow speeds characteristic of recurrent high-speed solar wind streams can be obtained only when the Alfven wave energy flux, deposited in the supersonic flow, is larger than the mechanical energy flux heating the corona.

  5. High geothermal heat flow, Basal melt, and the origin of rapid ice flow in central Greenland.

    PubMed

    Fahnestock, M; Abdalati, W; Joughin, I; Brozena, J; Gogineni, P

    2001-12-14

    Age-depth relations from internal layering reveal a large region of rapid basal melting in Greenland. Melt is localized at the onset of rapid ice flow in the large ice stream that drains north off the summit dome and other areas in the northeast quadrant of the ice sheet. Locally, high melt rates indicate geothermal fluxes 15 to 30 times continental background. The southern limit of melt coincides with magnetic anomalies and topography that suggest a volcanic origin. PMID:11743197

  6. Method of producing a plug-type heat flux gauge

    NASA Technical Reports Server (NTRS)

    Liebert, Curt H. (Inventor); Koch, John, Jr. (Inventor)

    1992-01-01

    A method of making a plug-type heat flux gauge in a material specimen in which a thermoplug is integrally formed in the specimen is disclosed. The thermoplug and concentric annulus are formed in the material specimen by electrical discharge machining and trepanning procedures. The thermoplug is surrounded by a concentric annulus through which thermocouple wires are routed. The end of each thermocouple wire is welded to the thermoplug, with each thermocouple wire welded at a different location along the length of the thermoplug.

  7. USE OF PELTIER COOLERS AS SOIL HEAT FLUX TRANSDUCERS.

    USGS Publications Warehouse

    Weaver, H.L.; Campbell, G.S.

    1985-01-01

    Peltier coolers were modified and calibrated to serve as soil heat flux transducers. The modification was to fill their interiors with epoxy. The average calibration constant on 21 units was 13. 6 plus or minus 0. 8 kW m** minus **2 V** minus **1 at 20 degree C. This sensitivity is about eight times that of the two thermopile transducers with which comparisons were made. The thermal conductivity of the Peltier cooler transducers was 0. 4 W m** minus **1 degree C** minus **1, which is comparable to that of dry soil.

  8. Geothermal Energy

    SciTech Connect

    Steele, B.C.; Harman, G.; Pitsenbarger, J.

    1996-02-01

    Geothermal Energy Technology (GET) announces on a bimonthly basis the current worldwide information available on the technologies required for economic recovery of geothermal energy and its use as direct heat or for electric power production.

  9. Investigation of Instabilities and Heat Transfer Phenomena in Supercritical Fuels at High Heat Flux and Temperatures

    NASA Technical Reports Server (NTRS)

    Linne, Diane L.; Meyer, Michael L.; Braun, Donald C.; Keller, Dennis J.

    2000-01-01

    A series of heated tube experiments was performed to investigate fluid instabilities that occur during heating of supercritical fluids. In these tests, JP-7 flowed vertically through small diameter tubes at supercritical pressures. Test section heated length, diameter, mass flow rate, inlet temperature, and heat flux were varied in an effort to determine the range of conditions that trigger the instabilities. Heat flux was varied up to 4 BTU/sq in./s, and test section wall temperatures reached as high as 1950 F. A statistical model was generated to explain the trends and effects of the control variables. The model included no direct linear effect of heat flux on the occurrence of the instabilities. All terms involving inlet temperature were negative, and all terms involving mass flow rate were positive. Multiple tests at conditions that produced instabilities provided inconsistent results. These inconsistencies limit the use of the model as a predictive tool. Physical variables that had been previously postulated to control the onset of the instabilities, such as film temperature, velocity, buoyancy, and wall-to-bulk temperature ratio, were evaluated here. Film temperatures at or near critical occurred during both stable and unstable tests. All tests at the highest velocity were stable, but there was no functional relationship found between the instabilities and velocity, or a combination of velocity and temperature ratio. Finally, all of the unstable tests had significant buoyancy at the inlet of the test section, but many stable tests also had significant buoyancy forces.

  10. Vitrinite reflectance geothermometry and apparent heating duration in the Cerro Prieto geothermal field

    USGS Publications Warehouse

    Barker, C.E.; Elders, W.A.

    1981-01-01

    Vitrinite reflectance measured in immersion oil (Ro) on kerogen extracted from hydrothermally altered mudstones in borehole M-84 at the Cerro Prieto geothermal field exhibit an increase in mean reflectance (Ro) from 0.12 per cent at 0.24 km depth to 4.1 per cent at 1.7 km depth. Downhole temperatures measured over this interval increase from about 60?? to 340??C. These Ro data plotted against temperature fall along an exponential curve with a coefficient of determination of about 0.8. Other boreholes sampled in the field show similar relationships. A regression curve calculated for temperature and Ro in borehole M-105 correctly predicts temperatures in other boreholes within the central portion of the geothermal system. The correlation between the reflectance values and logged temperature, together with consistent temperature estimates from fluid inclusion and oxygen isotope geothermometry, indicates that changes in Ro are an accurate and sensitive recorder of the maximum temperature attained. Therefore, vitrinite reflectance can be used in this geothermal system to predict the undisturbed temperature in a geothermal borehole during drilling before it regains thermal equilibrium. Although existing theoretical functions which relate Ro to temperature and duration of heating are inaccurate, empirical temperature-Ro curves are still useful for geothermometry. A comparison of temperature-Ro regression curves derived from nine boreholes within the Cerro Prieto system suggests that heating across the central portion of the field occurred penecontemporaneously, but varies near margins. Boreholes M-93 and M-94 appear to have cooled from their maximum temperatures, whereas M-3 and Prian-1 have only recently been heated. Comparison of the temperature-Ro data from the Salton Sea, California, geothermal system indicates that the duration of heating has been longer there than at the Cerro Prieto field. ?? 1981.

  11. Direct use of geothermal energy, Elko, Nevada district heating. Final report

    SciTech Connect

    Lattin, M.W.; Hoppe, R.D.

    1983-06-01

    In early 1978 the US Department of Energy, under its Project Opportunity Notice program, granted financial assistance for a project to demonstrate the direct use application of geothermal energy in Elko, Nevada. The project is to provide geothermal energy to three different types of users: a commercial office building, a commercial laundry and a hotel/casino complex, all located in downtown Elko. The project included assessment of the geothermal resource potential, resource exploration drilling, production well drilling, installation of an energy distribution system, spent fluid disposal facility, and connection of the end users buildings. The project was completed in November 1982 and the three end users were brought online in December 1982. Elko Heat Company has been providing continuous service since this time.

  12. Geothermal greenhouse-heating facilities for the Klamath County Nursing Home, Klamath Falls, Oregon

    SciTech Connect

    Not Available

    1982-02-01

    The Klamath County Nursing Home, located in Klamath Falls, Oregon, was constructed in 1976. The building of 55,654 square feet currently houses care facilities for approximately 120 persons. During the initial planning for the Nursing Home, the present site was selected primarily on the basis of its geothermal resource. This resource (approx. 190/sup 0/F) currently provides space and domestic hot water heating for the Nursing Home, Merle West Medical Center and the Oregon Institute of Technology. The feasibility of installing a geothermal heating system in a planned greenhouse for the Nursing Home is explored. The greenhouse system would be tied directly to the existing hot water heating system for the Nursing Home.

  13. Heat-tolerant flowering plants of active geothermal areas in Yellowstone National Park.

    PubMed

    Stout, Richard G; Al-Niemi, Thamir S

    2002-08-01

    A broad survey of most of the major geyser basins within Yellowstone National Park (Wyoming, USA) was conducted to identify the flowering plants which tolerate high rhizosphere temperatures (> or = 40 degrees C) in geothermally heated environments. Under such conditions, five species of monocots and four species of dicots were repeatedly found. The predominant flowering plants in hot soils (>40 degrees C at 2-5 cm depth) were grasses, primarily Dichanthelium lanuginosum. Long-term (weeks to months) rhizosphere temperatures of individual D. lanuginosum above 40 degrees C were recorded at several different locations, both in the summer and winter. The potential role of heat shock proteins (HSPs) in the apparent adaptation of these plants to chronically high rhizosphere temperatures was examined. Antibodies to cytoplasmic class I small heat shock proteins (sHSPs) and to HSP101 were used in Western immunoblot analyses of protein extracts from plants collected from geothermally heated soils. Relatively high levels of proteins reacting with anti-sHSP antibodies were consistently detected in root extracts from plants experiencing rhizosphere temperatures above 40 degrees C, though these proteins were usually not highly expressed in leaf extracts from the same plants. Proteins reacting with antibodies to HSP101 were also present both in leaf and root extracts from plants collected from geothermal soils, but their levels of expression were not as closely related to the degree of heat exposure as those of sHSPs.

  14. Heat-tolerant flowering plants of active geothermal areas in Yellowstone National Park.

    PubMed

    Stout, Richard G; Al-Niemi, Thamir S

    2002-08-01

    A broad survey of most of the major geyser basins within Yellowstone National Park (Wyoming, USA) was conducted to identify the flowering plants which tolerate high rhizosphere temperatures (> or = 40 degrees C) in geothermally heated environments. Under such conditions, five species of monocots and four species of dicots were repeatedly found. The predominant flowering plants in hot soils (>40 degrees C at 2-5 cm depth) were grasses, primarily Dichanthelium lanuginosum. Long-term (weeks to months) rhizosphere temperatures of individual D. lanuginosum above 40 degrees C were recorded at several different locations, both in the summer and winter. The potential role of heat shock proteins (HSPs) in the apparent adaptation of these plants to chronically high rhizosphere temperatures was examined. Antibodies to cytoplasmic class I small heat shock proteins (sHSPs) and to HSP101 were used in Western immunoblot analyses of protein extracts from plants collected from geothermally heated soils. Relatively high levels of proteins reacting with anti-sHSP antibodies were consistently detected in root extracts from plants experiencing rhizosphere temperatures above 40 degrees C, though these proteins were usually not highly expressed in leaf extracts from the same plants. Proteins reacting with antibodies to HSP101 were also present both in leaf and root extracts from plants collected from geothermal soils, but their levels of expression were not as closely related to the degree of heat exposure as those of sHSPs. PMID:12197524

  15. Heat and mass transfer in the Klamath Falls, Oregon, geothermal system

    SciTech Connect

    Prucha, R.H.

    1987-05-01

    Over the last 50 years significant amounts of data have been obtained from the Klamath Falls geothermal resource. To date, the complexity of the system has perplexed researchers, leading to the development of only very generalized hydrogeologic and geothermal models of the area. Based on reevaluation of all available data, a detailed conceptual model for the Klamath Falls geothermal resource is proposed. A comprehensive 3-dimensional numerical model, based on the proposed conceptual model is also presented. This numerical model incorporates all of the main reservoir characteristics. Hot water recharge flows from depth, along a large normal fault, and flows into near surface permeable strata where it loses heat to surrounding beds and to mixing with cold regional groundwaters introduced from the north. By matching calculated and measured temperatures and pressures, hot and cold water recharge rates and the permeability distribution for the geothermal system are estimated. A semi-analytic solution and simple lumped parameter methods are also compared to the numerical analysis. Results suggest that the flow patterns within the geothermal system at Klamath Falls are complex and intimately associated with the permeability distribution and the pressures and temperatures at depth, within the faults.

  16. The Surface Heat Flux as a Function of Ground Cover for Climate Models

    NASA Technical Reports Server (NTRS)

    Vukovich, Fred M.; Wayland, Robert; Toll, David

    1997-01-01

    Surface heat fluxes were examined as a function of surface properties and meteorological conditions in a 100 km x 100 km grid square at 1-km spatial resolution centered at the location of the First ISLSCP (International Satellite Land Surface Climatology Project) Field Experiment (FIFE), the Forest Ecosystem Dynamics site in central Maine, and a semiarid rangeland site around Walnut Gulch, Arizona. This investigation treats the surface heat flux variability within a GCM grid box to provide insight into methods for treating that variability in climate models. The heat fluxes were calculated using NOAA AVHRR and available meteorological data. The average heat fluxes that were estimated using the various area ground-cover representations were compared with the ensemble average heat fluxes for the entire area, which were assumed to be the best representation of the heat fluxes for the areas. Average beat fluxes were estimated for the entire 100 km x 100 km area based on a single ground-cover representation, and the mean error for the area sensible heat flux was about 10% and for the area latent heat flux, 21%. The estimation error was reduced, and in some cases significantly reduced, when the area heat fluxes were estimated by partitioning the area according to significant ground cover. The most significant effect of the partitioning was on the latent heat flux estimates.

  17. Diamond thin film temperature and heat-flux sensors

    NASA Technical Reports Server (NTRS)

    Aslam, M.; Yang, G. S.; Masood, A.; Fredricks, R.

    1995-01-01

    Diamond film temperature and heat-flux sensors are developed using a technology compatible with silicon integrated circuit processing. The technology involves diamond nucleation, patterning, doping, and metallization. Multi-sensor test chips were designed and fabricated to study the thermistor behavior. The minimum feature size (device width) for 1st and 2nd generation chips are 160 and 5 micron, respectively. The p-type diamond thermistors on the 1st generation test chip show temperature and response time ranges of 80-1270 K and 0.29-25 microseconds, respectively. An array of diamond thermistors, acting as heat flux sensors, was successfully fabricated on an oxidized Si rod with a diameter of 1 cm. Some problems were encountered in the patterning of the Pt/Ti ohmic contacts on the rod, due mainly to the surface roughness of the diamond film. The use of thermistors with a minimum width of 5 micron (to improve the spatial resolution of measurement) resulted in lithographic problems related to surface roughness of diamond films. We improved the mean surface roughness from 124 nm to 30 nm by using an ultra high nucleation density of 10(exp 11)/sq cm. To deposit thermistors with such small dimensions on a curved surface, a new 3-D diamond patterning technique is currently under development. This involves writing a diamond seed pattern directly on the curved surface by a computer-controlled nozzle.

  18. Flow and heat transfer of ferrofluids over a flat plate with uniform heat flux

    NASA Astrophysics Data System (ADS)

    Khan, W. A.; Khan, Z. H.; Haq, R. U.

    2015-04-01

    The present work is dedicated to analyze the flow and heat transport of ferrofluids along a flat plate subjected to uniform heat flux and slip velocity. A magnetic field is applied in the transverse direction to the plate. Moreover, three different kinds of magnetic nanoparticles (Fe3O4, CoFe2O4, Mn-ZnFe2O4 are incorporated within the base fluid. We have considered two different kinds of base fluids (kerosene and water) having poor thermal conductivity as compared to solid magnetic nanoparticles. Self-similar solutions are obtained and are compared with the available data for special cases. A simulation is performed for each ferrofluid mixture by considering the dominant effects of slip and uniform heat flux. It is found that the present results are in an excellent agreement with the existing literature. The variation of skin friction and heat transfer is also performed at the surface of the plate and then the better heat transfer and of each mixture is analyzed. Kerosene-based magnetite Fe3O4 provides the higher heat transfer rate at the wall as compared to the kerosene-based cobalt ferrite and Mn-Zn ferrite. It is also concluded that the primary effect of the magnetic field is to accelerate the dimensionless velocity and to reduce the dimensionless surface temperature as compared to the hydrodynamic case, thereby increasing the skin friction and the heat transfer rate of ferrofluids.

  19. Geothermal pipeline

    SciTech Connect

    1997-08-01

    The Geothermal Pipeline is a progress and development update from the Geothermal Progress Monitor and includes brief descriptions of various geothermal projects around the world. The following topics are covered: The retirement of Geo-Heat Center Director Paul Lienau, announcement of two upcoming geothermal meetings, and a proposed geothermal power plant project in the Medicine Lake/Glass Mountain area of California. Also included is an article about the Bonneville Power Administration`s settlements with two California companies who had agreed to build geothermal power plants on the federal agency`s behalf, geothermal space heating projects and use of geothermal energy for raising red crayfish in Oregon, and some updates on geothermal projects in Minnesota, Pennsylvania, and China.

  20. Geothermal solute flux monitoring and the source and fate of solutes in the Snake River, Yellowstone National Park, WY

    USGS Publications Warehouse

    McCleskey, R. Blaine; Lowenstern, Jacob B.; Schaper, Jonas; Nordstrom, D Kirk; Heasler, Henry P.; Mahony, Dan

    2016-01-01

    The combined geothermal discharge from over 10,000 features in Yellowstone National Park (YNP) can be can be estimated from the Cl flux in the Madison, Yellowstone, Falls, and Snake Rivers. Over the last 30 years, the Cl flux in YNP Rivers has been calculated using discharge measurements and Cl concentrations determined in discrete water samples and it has been determined that approximately 12% of the Cl flux exiting YNP is from the Snake River. The relationship between electrical conductivity and concentrations of Cl and other geothermal solutes was quantified at a monitoring site located downstream from the thermal inputs in the Snake River. Beginning in 2012, continuous (15 min) electrical conductivity measurements have been made at the monitoring site. Combining continuous electrical conductivity and discharge data, the Cl and other geothermal solute fluxes were determined. The 2013–2015 Cl fluxes (5.3–5.8 kt/yr) determined using electrical conductivity are comparable to historical data. In addition, synoptic water samples and discharge data were obtained from sites along the Snake River under low-flow conditions of September 2014. The synoptic water study extended 17 km upstream from the monitoring site. Surface inflows were sampled to identify sources and to quantify solute loading. The Lewis River was the primary source of Cl, Na, K, Cl, SiO2, Rb, and As loads (50–80%) in the Snake River. The largest source of SO4 was from the upper Snake River (50%). Most of the Ca and Mg (50–55%) originate from the Snake Hot Springs. Chloride, Ca, Mg, Na, K, SiO2, F, HCO3, SO4, B, Li, Rb, and As behave conservatively in the Snake River, and therefore correlate well with conductivity (R2 ≥ 0.97).

  1. Marketing the Klamath Falls Geothermal District Heating system

    SciTech Connect

    Rafferty, K.

    1993-06-01

    The new marketing strategy for the Klamath Falls system has concentrated on offering the customer an attractive and easy to understand rate structure, reduced retrofit cost and complexity for his building along with an attractive package of financing and tax credits. Initial retrofit costs and life-cycle cost analysis have been conducted on 22 buildings to date. For some, the retrofit costs are simply too high for the conversion to make sense at current geothermal rates. For many, however, the prospects are good. At this writing, two new customers are now connected and operating with 5 to 8 more buildings committed to connect this construction season after line extensions are completed. This represents nearly a 60% increase in the number of buildings connected to the system and a 40% increase in system revenue.

  2. Improving surface energy balance closure by reducing errors in soil heat flux measurement

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The flux plate method is the most commonly employed method for measuring soil heat flux (G) in surface energy balance studies. Although relatively simple to use, the flux plate method is susceptible to significant errors. Two of the most common errors are heat flow divergence around the plate and fa...

  3. Design and calibration of a novel transient radiative heat flux meter for a spacecraft thermal test.

    PubMed

    Sheng, Chunchen; Hu, Peng; Cheng, Xiaofang

    2016-06-01

    Radiative heat flux measurement is significantly important for a spacecraft thermal test. To satisfy the requirements of both high accuracy and fast response, a novel transient radiative heat flux meter was developed. Its thermal receiver consists of a central thermal receiver and two thermal guarded annular plates, which ensure the temperature distribution of the central thermal receiver to be uniform enough for reasonably applying lumped heat capacity method in a transient radiative heat flux measurement. This novel transient radiative heat flux meter design can also take accurate measurements regardless of spacecraft surface temperature and incident radiation spectrum. The measurement principle was elaborated and the coefficients were calibrated. Experimental results from testing a blackbody furnace and an Xenon lamp show that this novel transient radiative heat flux meter can be used to measure transient radiative heat flux up to 1400 W/m(2) with high accuracy and the response time of less than 10 s.

  4. Design and calibration of a novel transient radiative heat flux meter for a spacecraft thermal test.

    PubMed

    Sheng, Chunchen; Hu, Peng; Cheng, Xiaofang

    2016-06-01

    Radiative heat flux measurement is significantly important for a spacecraft thermal test. To satisfy the requirements of both high accuracy and fast response, a novel transient radiative heat flux meter was developed. Its thermal receiver consists of a central thermal receiver and two thermal guarded annular plates, which ensure the temperature distribution of the central thermal receiver to be uniform enough for reasonably applying lumped heat capacity method in a transient radiative heat flux measurement. This novel transient radiative heat flux meter design can also take accurate measurements regardless of spacecraft surface temperature and incident radiation spectrum. The measurement principle was elaborated and the coefficients were calibrated. Experimental results from testing a blackbody furnace and an Xenon lamp show that this novel transient radiative heat flux meter can be used to measure transient radiative heat flux up to 1400 W/m(2) with high accuracy and the response time of less than 10 s. PMID:27370482

  5. Development of advanced high-temperature heat flux sensors. Phase 2: Verification testing

    NASA Technical Reports Server (NTRS)

    Atkinson, W. H.; Cyr, M. A.; Strange, R. R.

    1985-01-01

    A two-phase program is conducted to develop heat flux sensors capable of making heat flux measurements throughout the hot section of gas turbine engines. In Phase 1, three types of heat flux sensors are selected; embedded thermocouple, laminated, and Gardon gauge sensors. A demonstration of the ability of these sensors to operate in an actual engine environment is reported. A segmented liner of each of two combustors being used in the Broad Specification Fuels Combustor program is instrumented with the three types of heat flux sensors then tested in a high pressure combustor rig. Radiometer probes are also used to measure the radiant heat loads to more fully characterize the combustor environment. Test results show the heat flux sensors to be in good agreement with radiometer probes and the predicted data trends. In general, heat flux sensors have strong potential for use in combustor development programs.

  6. Design and calibration of a novel transient radiative heat flux meter for a spacecraft thermal test

    NASA Astrophysics Data System (ADS)

    Sheng, Chunchen; Hu, Peng; Cheng, Xiaofang

    2016-06-01

    Radiative heat flux measurement is significantly important for a spacecraft thermal test. To satisfy the requirements of both high accuracy and fast response, a novel transient radiative heat flux meter was developed. Its thermal receiver consists of a central thermal receiver and two thermal guarded annular plates, which ensure the temperature distribution of the central thermal receiver to be uniform enough for reasonably applying lumped heat capacity method in a transient radiative heat flux measurement. This novel transient radiative heat flux meter design can also take accurate measurements regardless of spacecraft surface temperature and incident radiation spectrum. The measurement principle was elaborated and the coefficients were calibrated. Experimental results from testing a blackbody furnace and an Xenon lamp show that this novel transient radiative heat flux meter can be used to measure transient radiative heat flux up to 1400 W/m2 with high accuracy and the response time of less than 10 s.

  7. A Comparison of Latent Heat Fluxes over Global Oceans for Four Flux Products

    NASA Technical Reports Server (NTRS)

    Chou, Shu-Hsien; Nelkin, Eric; Ardizzone, Joe; Atlas, Robert M.

    2003-01-01

    To improve our understanding of global energy and water cycle variability, and to improve model simulations of climate variations, it is vital to have accurate latent heat fluxes (LHF) over global oceans. Monthly LHF, 10-m wind speed (U10m), 10-m specific humidity (Q10h), and sea-air humidity difference (Qs-Q10m) of GSSTF2 (version 2 Goddard Satellite-based Surface Turbulent Fluxes) over global Oceans during 1992-93 are compared with those of HOAPS (Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data), NCEP (NCEP/NCAR reanalysis). The mean differences, standard deviations of differences, and temporal correlation of these monthly variables over global Oceans during 1992-93 between GSSTF2 and each of the three datasets are analyzed. The large-scale patterns of the 2yr-mean fields for these variables are similar among these four datasets, but significant quantitative differences are found. The temporal correlation is higher in the northern extratropics than in the south for all variables, with the contrast being especially large for da Silva as a result of more missing ship data in the south. The da Silva has extremely low temporal correlation and large differences with GSSTF2 for all variables in the southern extratropics, indicating that da Silva hardly produces a realistic variability in these variables. The NCEP has extremely low temporal correlation (0.27) and large spatial variations of differences with GSSTF2 for Qs-Q10m in the tropics, which causes the low correlation for LHF. Over the tropics, the HOAPS LHF is significantly smaller than GSSTF2 by approx. 31% (37 W/sq m), whereas the other two datasets are comparable to GSSTF2. This is because the HOAPS has systematically smaller LHF than GSSTF2 in space, while the other two datasets have very large spatial variations of large positive and negative LHF differences with GSSTF2 to cancel and to produce smaller regional-mean differences. Our analyses suggest that the GSSTF2 latent heat flux

  8. Latent Heat and Sensible Heat Fluxes Simulation in Maize Using Artificial Neural Networks

    NASA Astrophysics Data System (ADS)

    Safa, B.

    2015-12-01

    Latent Heat (LE) and Sensible Heat (H) flux are two major components of the energy balance at the earth's surface which play important roles in the water cycle and global warming. There are various methods for their estimation or measurement. Eddy covariance is a direct and accurate technique for their measurement. Some limitations lead to prevention of the extensive use of the eddy covariance technique. Therefore, simulation approaches can be utilized for their estimation. ANNs are the information processing systems, which can inspect the empirical data and investigate the relations (hidden rules) among them, and then make the network structure. In this study, multi-layer perceptron neural network trained by the steepest descent Back-Propagation (BP) algorithm was tested to simulate LE and H flux above two maize sites (rain-fed & irrigated) near Mead, Nebraska. Network training and testing was fulfilled using hourly data of including year, local time of day (DTime), leaf area index (LAI), soil water content (SWC) in 10 and 25 cm depths, soil temperature (Ts) in 10 cm depth, air temperature (Ta), vapor pressure deficit (VPD), wind speed (WS), irrigation and precipitation (P), net radiation (Rn), and the fraction of incoming Photosynthetically Active Radiation (PAR) absorbed by the canopy (fPAR), which were selected from days of year (DOY) 169 to 222 for 2001, 2003, 2005, 2007, and 2009. The results showed high correlation between actual and estimated data; the R² values for LE flux in irrigated and rain-fed sites were 0.9576, and 0.9642; and for H flux 0.8001, and 0.8478, respectively. Furthermore, the RMSE values ranged from 0.0580 to 0.0721 W/m² for LE flux and from 0.0824 to 0.0863 W/m² for H flux. In addition, the sensitivity of the fluxes with respect to each input was analyzed over the growth stages. Thus, the most powerful effects among the inputs for LE flux were identified net radiation, leaf area index, vapor pressure deficit, wind speed, and for H

  9. Solute fluxes and geothermal potential of Tacaná volcano-hydrothermal system, Mexico-Guatemala

    NASA Astrophysics Data System (ADS)

    Collard, Nathalie; Taran, Yuri; Peiffer, Loïc; Campion, Robin; Jácome Paz, Mariana P.

    2014-11-01

    Solute and heat fluxes from thermal springs of Tacaná volcano are estimated by the chloride-inventory method. The thermal springs, located at the northwestern slopes of the volcanic edifice, at altitudes from 1500 to 2000 m above sea level, discharge water enriched in HCO3 and SO4 (up to 1 g kg- 1 of each one) with temperatures in the 25-63 °C range. There are two distinct groups of springs with a different 'chloride-temperature' correlation but with the same 87Sr/86Sr ratio (0.7046 ± 0.0001) indicating the same wall rock composition for different aquifers. Each thermal spring feeds a thermal stream that flows into the main drainage of the area, Río Coatán. The total observed chloride discharge from the thermal springs is estimated as 14.8 g s- 1 and the total measured heat output of ~ 9.5 MW. Considering a deep fluid temperature of 250 °C (calculated using Na-K geothermometer), the corresponding advective heat transport from the deep reservoirs that feed these springs may be estimated as 26 MWt. However, the total chloride output measured in the main drainage (Coatán river) is 4 times higher (~ 59 g s- 1) than the measured Cl output of thermal springs. This means that other, undiscovered, thermal springs exist in the area and that the natural heat output through thermal springs at Tacaná is significantly higher and depends on the Cl content and temperatures of the unknown thermal water discharges. If chloride concentration in these unknown springs does not exceed 540 mg L- 1 (the highest analyzed Cl in Tacaná springs) and the discharge temperature is 50 °C, then the natural heat output can be estimated at least as 22 MWt and the corresponding advective heat transport as ~ 100 MWt.

  10. The surface latent heat flux anomalies related to major earthquake

    NASA Astrophysics Data System (ADS)

    Jing, Feng; Shen, Xuhui; Kang, Chunli; Xiong, Pan; Hong, Shunying

    2011-12-01

    SLHF (Surface Latent Heat Flux) is an atmospheric parameter, which can describe the heat released by phase changes and dependent on meteorological parameters such as surface temperature, relative humidity, wind speed etc. There is a sharp difference between the ocean surface and the land surface. Recently, many studies related to the SLHF anomalies prior to earthquakes have been developed. It has been shown that the energy exchange enhanced between coastal surface and atmosphere prior to earthquakes can increase the rate of the water-heat exchange, which will lead to an obviously increases in SLHF. In this paper, two earthquakes in 2010 (Haiti earthquake and southwest of Sumatra in Indonesia earthquake) have been analyzed using SLHF data by STD (standard deviation) threshold method. It is shows that the SLHF anomaly may occur in interpolate earthquakes or intraplate earthquakes and coastal earthquakes or island earthquakes. And the SLHF anomalies usually appear 5-6 days prior to an earthquake, then disappear quickly after the event. The process of anomaly evolution to a certain extent reflects a dynamic energy change process about earthquake preparation, that is, weak-strong-weak-disappeared.

  11. Flathead Electric Cooperative Facility Geothermal Heat Pump System Upgrade

    SciTech Connect

    Liu, Xiaobing

    2014-06-01

    High initial cost and lack of public awareness of ground source heat pump (GSHP) technology are the two major barriers preventing rapid deployment of this energy saving technology in the United States. Under the American Recovery and Reinvestment Act (ARRA), 26 GSHP projects have been competitively selected and carried out to demonstrate the benefits of GSHP systems and innovative technologies for cost reduction and/or performance improvement. This paper highlights findings of a case study of one of the ARRA-funded GSHP demonstration projects, which is a heating only central GSHP system using shallow aquifer as heat source and installed at a warehouse and truck bay at Kalispell, MT. This case study is based on the analysis of measured performance data, utility bills, and calculations of energy consumptions of conventional central heating systems for providing the same heat outputs as the central GSHP system did. The evaluated performance metrics include energy efficiency of the heat pump equipment and the overall GSHP system, pumping performance, energy savings, carbon emission reductions, and cost-effectiveness of GSHP system compared with conventional heating systems. This case study also identified areas for reducing uncertainties in performance evaluation, improving operational efficiency, and reducing installed cost of similar GSHP systems in the future. Publication of ASHRAE at the annual conference in Seattle.

  12. Flathead Electric Cooperative Facility Geothermal Heat Pump System Upgrade.

    SciTech Connect

    Liu, Xiaobing

    2014-06-01

    High initial cost and lack of public awareness of ground source heat pump (GSHP) technology are the two major barriers preventing rapid deployment of this energy saving technology in the United States. Under the American Recovery and Reinvestment Act (ARRA), 26 GSHP projects have been competitively selected and carried out to demonstrate the benefits of GSHP systems and innovative technologies for cost reduction and/or performance improvement. This paper highlights findings of a case study of one of the ARRA-funded GSHP demonstration projects, which is a heating only central GSHP system using shallow aquifer as heat source and installed at a warehouse and truck bay at Kalispell, MT. This case study is based on the analysis of measured performance data, utility bills, and calculations of energy consumptions of conventional central heating systems for providing the same heat outputs as the central GSHP system did. The evaluated performance metrics include energy efficiency of the heat pump equipment and the overall GSHP system, pumping performance, energy savings, carbon emission reductions, and cost-effectiveness of GSHP system compared with conventional heating systems. This case study also identified areas for reducing uncertainties in performance evaluation, improving operational efficiency, and reducing installed cost of similar GSHP systems in the future. Publication of ASHRAE at the annual conference in Seattle June 2014.

  13. Numerical and experimental analyses of the radiant heat flux produced by quartz heating systems

    NASA Technical Reports Server (NTRS)

    Turner, Travis L.; Ash, Robert L.

    1994-01-01

    A method is developed for predicting the radiant heat flux distribution produced by tungsten filament, tubular fused-quartz envelope heating systems with reflectors. The method is an application of Monte Carlo simulation, which takes the form of a random walk or ray tracing scheme. The method is applied to four systems of increasing complexity, including a single lamp without a reflector, a single lamp with a Hat reflector, a single lamp with a parabolic reflector, and up to six lamps in a six-lamp contoured-reflector heating unit. The application of the Monte Carlo method to the simulation of the thermal radiation generated by these systems is discussed. The procedures for numerical implementation are also presented. Experiments were conducted to study these quartz heating systems and to acquire measurements of the corresponding empirical heat flux distributions for correlation with analysis. The experiments were conducted such that several complicating factors could be isolated and studied sequentially. Comparisons of the experimental results with analysis are presented and discussed. Good agreement between the experimental and simulated results was obtained in all cases. This study shows that this method can be used to analyze very complicated quartz heating systems and can account for factors such as spectral properties, specular reflection from curved surfaces, source enhancement due to reflectors and/or adjacent sources, and interaction with a participating medium in a straightforward manner.

  14. Comparison of Turbulent Heat-Transfer Results for Uniform Wall Heat Flux and Uniform Wall Temperature

    NASA Technical Reports Server (NTRS)

    Siegel, R.; Sparrow, E. M.

    1960-01-01

    The purpose of this note is to examine in a more precise way how the Nusselt numbers for turbulent heat transfer in both the fully developed and thermal entrance regions of a circular tube are affected by two different wall boundary conditions. The comparisons are made for: (a) Uniform wall temperature (UWT); and (b) uniform wall heat flux (UHF). Several papers which have been concerned with the turbulent thermal entrance region problem are given. 1 Although these analyses have all utilized an eigenvalue formulation for the thermal entrance region there were differences in the choices of eddy diffusivity expressions, velocity distributions, and methods for carrying out the numerical solutions. These differences were also found in the fully developed analyses. Hence when making a comparison of the analytical results for uniform wall temperature and uniform wall heat flux, it was not known if differences in the Nusselt numbers could be wholly attributed to the difference in wall boundary conditions, since all the analytical results were not obtained in a consistent way. To have results which could be directly compared, computations were carried out for the uniform wall temperature case, using the same eddy diffusivity, velocity distribution, and digital computer program employed for uniform wall heat flux. In addition, the previous work was extended to a lower Reynolds number range so that comparisons could be made over a wide range of both Reynolds and Prandtl numbers.

  15. Coronal Heating and the Magnetic Flux Content of the Network

    NASA Technical Reports Server (NTRS)

    Falconer, D. A.; Moore, R. L.; Porter, J. G.; Hathaway, D. H.; Whitaker, Ann F. (Technical Monitor)

    2001-01-01

    Previously, from analysis of SOHO/EIT coronal images in combination with Kitt Peak magnetograms (Falconer et al 1998, ApJ, 501, 386-396), we found that the quiet corona is the sum of two components: the e-scale corona and the coronal network. The large-scale corona consists of all coronal-temperature (T approx. 10(exp 6) K) structures larger than supergranules (>approx.30,000 km). The coronal network (1) consists of all coronal-temperature structures smaller than supergranules, (2) is rooted in and loosely traces the photospheric magnetic network, (3) has its brightest features seated on polarity dividing fines (neutral lines) in the network magnetic flux, and (4) produces only about 5% of the total coronal emission in quiet regions. The heating of the coronal network is apparently magnetic in origin. Here, from analysis of EIT coronal images of quiet regions in combination with magnetograms of the same quiet regions from SOHO/MDI and from Kitt Peak, we examine the other 95% of the quiet corona and its relation to the underlying magnetic network. We find: (1) Dividing the large-scale corona into its bright and dim halves divides the area into bright "continents" and dark "oceans" having spans of 2-4 supergranules. (2) These patterns are also present in the photospheric magnetograms: the network is stronger under the bright half and weaker under the dim half. (3) The radiation from the large-scale corona increases roughly as the cube root of the magnetic flux content of the underlying magnetic network. In contrast, Fisher et A (1998, ApJ, 508, 985-998) found that the coronal radiation from an active region increases roughly linearly with the magnetic flux content of the active region. We assume, as is widely held, that nearly all of the large-scale corona is magnetically rooted in the network. Our results, together with the result of Fisher et al (1999), suggest that either the coronal heating in quiet regions has a large non-magnetic component, or, if the heating

  16. Numerical simulation of fluid implementing heat transfer in naturally fractured geothermal reservoir with DFN method

    NASA Astrophysics Data System (ADS)

    Lee, T.; Kim, K.; Lee, K.; Lee, H.; Lee, W.

    2015-12-01

    Natural fractures have an effect on the fluid flow and heat transfer in the naturally fractured geothermal reservoir. However, most of the previous works in this area assumed that reservoir systems are continuum model whether it is single continuum or dual continuum. Moreover, some people have studied without continuum model but, it was just pipeline model. In this paper, we developed a generalized discrete fracture network (DFN) geothermal reservoir simulator. In the model, 2D flow is possible within a rectangular fracture, which is important in thick naturally fractured reservoirs. The DFN model developed in this study was validated for two synthetic fracture systems using a commercial thermal model, TETRAD. Comparison results showed an excellent matching between both models. However, this model is only fracture model and it can't calculate simulation of fluid flow and heat transfer in matrix. Therefore, matrix flow model will be added to this model.

  17. Use of geothermal heat for sugar refining in Imperial County: pilot plant implementation

    SciTech Connect

    Not Available

    1984-09-01

    The objective of the phase was to develop a successful geothermal resource and use it in conjunction with a geothermal process heat pilot plant to demonstrate the adequacy of a system which could provide technically sound, economical and environmentally acceptable process heat. During the second phase drilling of and exploratory production well was carried out. The well reached a total depth of about 10,000 feet. Static bottom hole temperatures as high as 393 degreees F were calculated. However, the well did not produce a free flow of more than 2 to 3 barrels of brine per hour. Attempts were made to stimulate the well by gas lift and circulation. These procedures were unsuccessful in promoting flow, and the well was shut in. At that point the DOE decided to terminate the project.

  18. Comprehensive Analysis of Convective Heat Transfer in Parallel Plate Microchannel with Viscous Dissipation and Constant Heat Flux Boundary Conditions

    NASA Astrophysics Data System (ADS)

    Kushwaha, Hari Mohan; Sahu, Santosh Kumar

    2016-06-01

    This paper reports the hydrodynamically and thermally fully developed, laminar, incompressible, forced convective heat transfer characteristics of gaseous flows through a parallel plate microchannel with different constant heat flux boundary conditions. The first order velocity slip and viscous dissipation effects are considered in the analysis. Here, three different thermal boundary conditions such as: both plates kept at different constant heat fluxes, both plates kept at equal constant heat fluxes and one plate kept at constant heat flux and other one insulated are considered for the analysis. The deviation in Nusselt number between the model that considers both first order velocity slip and temperature jump and the one that considers only velocity slip is reported. Also, the effect of various heat flux ratios on the Nusselt number is reported in this analysis. In addition, the deviation in Nusselt number between first and second order slip model is discussed in this study.

  19. Thermionic Power Cell To Harness Heat Energies for Geothermal Applications

    NASA Technical Reports Server (NTRS)

    Manohara, Harish; Mojarradi, Mohammad; Greer, Harold F.

    2011-01-01

    A unit thermionic power cell (TPC) concept has been developed that converts natural heat found in high-temperature environments (460 to 700 C) into electrical power for in situ instruments and electronics. Thermionic emission of electrons occurs when an emitter filament is heated to gwhite hot h temperatures (>1,000 C) allowing electrons to overcome the potential barrier and emit into the vacuum. These electrons are then collected by an anode, and transported to the external circuit for energy storage.

  20. Methodology for the evaluation of a 4000-home geothermal heat pump retrofit at Fort Polk, Louisiana

    SciTech Connect

    Hughes, P.J.; Shonder, J.A.; White, D.L.; Huang, H.L.

    1998-03-01

    The US Army and a private energy service company are developing a comprehensive energy efficiency project to upgrade the family housing at Fort Polk, Louisiana. The project includes converting the space conditioning systems of more than 4,000 housing units to geothermal (or ground-source) heat pumps (GHPs). This interim report describes the methodology of the evaluation associated with this project, including the field monitoring that has been conducted at the base.

  1. Floral-greenhouse geothermal-heating demonstration. Final report, January 24, 1979-September 30, 1982

    SciTech Connect

    Not Available

    1982-10-01

    The planning and execution of a commercial geothermal development program for heating floral greenhouses are summarized. The program site was the Utah Roses property located about four miles from the Wasatch Mountains Faultline at Sandy in Salt Lake County, Utah. The report is concerned with four primary project features: a) resource exploration; b) well drilling and testing; c) production and distribution; and d) economics of resource development and use.

  2. Value analysis of advanced heat rejection systems for geothermal power plants

    SciTech Connect

    Bliem, C.; Zangrando, F.; Hassani, V.

    1996-12-31

    A computer model and a methodology has been developed to perform value analysis for small, low-temperature binary geothermal power plants. The value analysis method allows for incremental changes in the levelized energy cost (LEC) to be determined between a baseline plant and a modified plant. Thermodynamic cycle analyses and component sizing are carried out in the model followed by economic analysis which provides LEC results. The emphasis of the present work has been on evaluating different types of heat rejection systems.

  3. Geothermal Heat Pumps as a Cost Saving and Capital Renewal Too!

    SciTech Connect

    Hughes, P.J.

    1998-11-06

    An independent evaluation of the Fort Polk, Louisiana energy savings performance contract (ESPC) has verified the financial value of geothermal heat pump (GHP)-centered ESPCS to the federal government. The Department of Energy (DOE) Federal Energy Management Program (FEMP) has responded by issuing an RFP for the "National GHP-Technology-Specific Super ESPC Procurement." Federal agency sites anywhere in the nation will be able to implement GHP-centered ESPC projects as delivery orders against the awarded contracts.

  4. Geothermal-district-heating assessment model for decision making

    SciTech Connect

    Reisman, A.

    1981-11-01

    A methodology developed to assess the economic feasibility of district heating for any community in the United States is described. The overall philosophy which has guided its development is the conviction that district heating must be examined on a site-by-site basis. To support this approach, a set of extensive, in-house supporting data bases has been created and useful external data bases with national coverage have been identified. These data bases provide information at a sufficient level of detail to permit a first-cut examination of the district heating potential of a community without requiring outside data collection (allowing a substantial cost and time savings). The results of this blind look at a community permit a rapid, yet adequate estimate of district heating potential, costs, and energy savings. The data utilized in the initial examination can be supplemented or replaced by more detailed information obtained from on-site data collection, if the first results are promising. The fact that the data and methodology are computerized allows many locations within the community, alternate heat sources, ownership options, pipe technologies, etc. to be examined in a short period of time. The structure of the District Heating Model (DHM) (the methodology in computerized form) is described followed by a discussion of the application of the model to Provo, UT.

  5. Estimation of sensible heat flux from remotely sensed canopy temperatures

    NASA Technical Reports Server (NTRS)

    Vining, R. C.; Blad, B. L.

    1992-01-01

    Temperatures of tallgrass priarie vegetation were measured with infrared thermometers (IRT) at different view zenith and azimuth angles. The optimum IRT view zenith angle for estimating sensible heat fluxes (H) was determined by comparing H estimated with eddy correlation and/or Bowen ratio techniques to H calculated by a method suggested by Hatfield et al. (1984). For wind speeds of 5 m/s or greater, H estimated with surface temperatures measured at a 0 deg or 20 deg view zenith angle gave the best agreement, but for wind speeds of less than 4 m/s the best estimate of H was made with surface temperatures measured at a 40 deg or 60 deg view zenith angle.

  6. Heat flux sensor research and development: The cool film calorimeter

    NASA Technical Reports Server (NTRS)

    Abtahi, A.; Dean, P.

    1990-01-01

    The goal was to meet the measurement requirement of the NASP program for a gauge capable of measuring heat flux into a 'typical' structure in a 'typical' hypersonic flight environment. A device is conceptually described that has fast response times and is small enough to fit in leading edge or cowl lip structures. The device relies heavily on thin film technology. The main conclusion is the description of the limitations of thin film technology both in the art of fabrication and in the assumption that thin films have the same material properties as the original bulk material. Three gauges were designed and fabricated. Thin film deposition processes were evaluated. The effect of different thin film materials on the performance and fabrication of the gauge was studied. The gauges were tested in an arcjet facility. Survivability and accuracy were determined under various hostile environment conditions.

  7. A laser-induced heat flux technique for convective heat transfer measurements in high speed flows

    NASA Technical Reports Server (NTRS)

    Porro, A. R.; Keith, T. G., Jr.; Hingst, W. R.

    1991-01-01

    A technique is developed to measure the local convective heat transfer coefficient on a model surface in a supersonic flow field. The technique uses a laser to apply a discrete local heat flux at the model test surface, and an infrared camera system determines the local temperature distribution due to the heating. From this temperature distribution and an analysis of the heating process, a local convective heat transfer coefficient is determined. The technique was used to measure the local surface convective heat transfer coefficient distribution on a flat plate at nominal Mach numbers of 2.5, 3.0, 3.5, and 4.0. The flat plate boundary layer initially was laminar and became transitional in the measurement region. The experimentally determined convective heat transfer coefficients were generally higher than the theoretical predictions for flat plate laminar boundary layers. However, the results indicate that this nonintrusive optical measurement technique has the potential to measure surface convective heat transfer coefficients in high speed flow fields.

  8. Heat transfer measurements in metal foam subjected to constant heat flux

    SciTech Connect

    Dukhan, Nihad; Chen, Kuan-Chih

    2007-11-15

    The use of open-cell metal foam in numerous technologies is increasing rapidly. Heat transfer measurements inside rectangular blocks of commercially available aluminum foam subjected to constant heat flux at one side are presented. Cases for different pore velocities, porosities and pore densities of the foam are given. Each foam block is cooled by a confined stream of ambient air. The temperature profile decays in an exponential fashion as the distance from the heat base increases. A two-dimensional, simplified analytical model for the heat transfer in the foam is summarized and adapted from the literature. The model neglects conduction in the fluid and invokes the local thermal equilibrium assumption for the solid and fluid phases in the foam. The model underestimated the temperature close to the foam's entrance, and predicted the temperatures inside the foam within the experimental uncertainty for most of the data points. (author)

  9. Prediction of heat transfer of nanofluid on critical heat flux based on fractal geometry

    NASA Astrophysics Data System (ADS)

    Xiao, Bo-Qi

    2013-01-01

    Analytical expressions for nucleate pool boiling heat transfer of nanofluid in the critical heat flux (CHF) region are derived taking into account the effect of nanoparticles moving in liquid based on the fractal geometry theory. The proposed fractal model for the CHF of nanofluid is explicitly related to the average diameter of the nanoparticles, the volumetric nanoparticle concentration, the thermal conductivity of nanoparticles, the fractal dimension of nanoparticles, the fractal dimension of active cavities on the heated surfaces, the temperature, and the properties of the fluid. It is found that the CHF of nanofluid decreases with the increase of the average diameter of nanoparticles. Each parameter of the proposed formulas on CHF has a clear physical meaning. The model predictions are compared with the existing experimental data, and a good agreement between the model predictions and experimental data is found. The validity of the present model is thus verified. The proposed fractal model can reveal the mechanism of heat transfer in nanofluid.

  10. Hybrid Heat Pipes for Lunar and Martian Surface and High Heat Flux Space Applications

    NASA Technical Reports Server (NTRS)

    Ababneh, Mohammed T.; Tarau, Calin; Anderson, William G.; Farmer, Jeffery T.; Alvarez-Hernandez, Angel R.

    2016-01-01

    Novel hybrid wick heat pipes are developed to operate against gravity on planetary surfaces, operate in space carrying power over long distances and act as thermosyphons on the planetary surface for Lunar and Martian landers and rovers. These hybrid heat pipes will be capable of operating at the higher heat flux requirements expected in NASA's future spacecraft and on the next generation of polar rovers and equatorial landers. In addition, the sintered evaporator wicks mitigate the start-up problems in vertical gravity aided heat pipes because of large number of nucleation sites in wicks which will allow easy boiling initiation. ACT, NASA Marshall Space Flight Center, and NASA Johnson Space Center, are working together on the Advanced Passive Thermal experiment (APTx) to test and validate the operation of a hybrid wick VCHP with warm reservoir and HiK"TM" plates in microgravity environment on the ISS.

  11. SPECTRAL data-based estimation of soil heat flux

    USGS Publications Warehouse

    Singh, R.K.; Irmak, A.; Walter-Shea, Elizabeth; Verma, S.B.; Suyker, A.E.

    2011-01-01

    Numerous existing spectral-based soil heat flux (G) models have shown wide variation in performance for maize and soybean cropping systems in Nebraska, indicating the need for localized calibration and model development. The objectives of this article are to develop a semi-empirical model to estimate G from a normalized difference vegetation index (NDVI) and net radiation (R n) for maize (Zea mays L.) and soybean (Glycine max L.) fields in the Great Plains, and present the suitability of the developed model to estimate G under similar and different soil and management conditions. Soil heat fluxes measured in both irrigated and rainfed fields in eastern and south-central Nebraska were used for model development and validation. An exponential model that uses NDVI and Rn was found to be the best to estimate G based on r2 values. The effect of geographic location, crop, and water management practices were used to develop semi-empirical models under four case studies. Each case study has the same exponential model structure but a different set of coefficients and exponents to represent the crop, soil, and management practices. Results showed that the semi-empirical models can be used effectively for G estimation for nearby fields with similar soil properties for independent years, regardless of differences in crop type, crop rotation, and irrigation practices, provided that the crop residue from the previous year is more than 4000 kg ha-1. The coefficients calibrated from particular fields can be used at nearby fields in order to capture temporal variation in G. However, there is a need for further investigation of the models to account for the interaction effects of crop rotation and irrigation. Validation at an independent site having different soil and crop management practices showed the limitation of the semi-empirical model in estimating G under different soil and environment conditions. ?? 2011 American Society of Agricultural and Biological Engineers ISSN 2151-0032.

  12. Approaching the limits of two-phase boiling heat transfer: High heat flux and low superheat

    NASA Astrophysics Data System (ADS)

    Palko, J. W.; Zhang, C.; Wilbur, J. D.; Dusseault, T. J.; Asheghi, M.; Goodson, K. E.; Santiago, J. G.

    2015-12-01

    We demonstrate capillary fed porous copper structures capable of dissipating over 1200 W cm-2 in boiling with water as the working fluid. Demonstrated superheats for this structure are dramatically lower than those previously reported at these high heat fluxes and are extremely insensitive to heat input. We show superheats of less than 10 K at maximum dissipation and varying less than 5 K over input heat flux ranges of 1000 W cm-2. Fabrication of the porous copper layers using electrodeposition around a sacrificial template allows fine control of both microstructure and bulk geometry, producing structures less than 40 μm thick with active region lateral dimensions of 2 mm × 0.3 mm. The active region is volumetrically Joule heated by passing an electric current through the porous copper bulk material. We analyze the heat transfer performance of the structures and suggest a strong influence of pore size on superheat. We compare performance of the current structure to existing wick structures.

  13. Measurements of absorbed heat flux and water-side heat transfer coefficient in water wall tubes

    NASA Astrophysics Data System (ADS)

    Taler, Jan; Taler, Dawid; Kowal, Andrzej

    2011-04-01

    The tubular type instrument (flux tube) was developed to identify boundary conditions in water wall tubes of steam boilers. The meter is constructed from a short length of eccentric tube containing four thermocouples on the fire side below the inner and outer surfaces of the tube. The fifth thermocouple is located at the rear of the tube on the casing side of the water-wall tube. The boundary conditions on the outer and inner surfaces of the water flux-tube are determined based on temperature measurements at the interior locations. Four K-type sheathed thermocouples of 1 mm in diameter, are inserted into holes, which are parallel to the tube axis. The non-linear least squares problem is solved numerically using the Levenberg-Marquardt method. The heat transfer conditions in adjacent boiler tubes have no impact on the temperature distribution in the flux tubes.

  14. Heat conduction in nanoscale materials: a statistical-mechanics derivation of the local heat flux.

    PubMed

    Li, Xiantao

    2014-09-01

    We derive a coarse-grained model for heat conduction in nanoscale mechanical systems. Starting with an all-atom description, this approach yields a reduced model, in the form of conservation laws of momentum and energy. The model closure is accomplished by introducing a quasilocal thermodynamic equilibrium, followed by a linear response approximation. Of particular interest is the constitutive relation for the heat flux, which is expressed nonlocally in terms of the spatial and temporal variation of the temperature. Nanowires made of copper and silicon are presented as examples. PMID:25314400

  15. Geothermal Resource/Reservoir Investigations Based on Heat Flow and Thermal Gradient Data for the United States

    SciTech Connect

    D. D. Blackwell; K. W. Wisian; M. C. Richards; J. L. Steele

    2000-04-01

    Several activities related to geothermal resources in the western United States are described in this report. A database of geothermal site-specific thermal gradient and heat flow results from individual exploration wells in the western US has been assembled. Extensive temperature gradient and heat flow exploration data from the active exploration of the 1970's and 1980's were collected, compiled, and synthesized, emphasizing previously unavailable company data. Examples of the use and applications of the database are described. The database and results are available on the world wide web. In this report numerical models are used to establish basic qualitative relationships between structure, heat input, and permeability distribution, and the resulting geothermal system. A series of steady state, two-dimensional numerical models evaluate the effect of permeability and structural variations on an idealized, generic Basin and Range geothermal system and the results are described.

  16. Carbon isotope and abundance systematics of Icelandic geothermal gases, fluids and subglacial basalts with implications for mantle plume-related CO2 fluxes

    NASA Astrophysics Data System (ADS)

    Barry, P. H.; Hilton, D. R.; Füri, E.; Halldórsson, S. A.; Grönvold, K.

    2014-06-01

    We report new carbon dioxide (CO2) abundance and isotope data for 71 geothermal gases and fluids from both high-temperature (HT > 150 °C at 1 km depth) and low-temperature (LT < 150 °C at 1 km depth) geothermal systems located within neovolcanic zones and older segments of the Icelandic crust, respectively. These data are supplemented by CO2 data obtained by stepped heating of 47 subglacial basaltic glasses collected from the neovolcanic zones. The sample suite has been characterized previously for He-Ne (geothermal) and He-Ne-Ar (basalt) systematics (Füri et al., 2010), allowing elemental ratios to be calculated for individual samples. Geothermal fluids are characterized by a wide range in carbon isotope ratios (δ13C), from -18.8‰ to +4.6‰ (vs. VPDB), and CO2/3He values that span eight orders of magnitude, from 1 × 104 to 2 × 1012. Extreme geothermal values suggest that original source compositions have been extensively modified by hydrothermal processes such as degassing and/or calcite precipitation. Basaltic glasses are also characterized by a wide range in δ13C values, from -27.2‰ to -3.6‰, whereas CO2/3He values span a narrower range, from 1 × 108 to 1 × 1012. The combination of both low δ13C values and low CO2 contents in basalts indicates that magmas are extensively and variably degassed. Using an equilibrium degassing model, we estimate that pre-eruptive basaltic melts beneath Iceland contain ∼531 ± 64 ppm CO2 with δ13C values of -2.5 ± 1.1‰, in good agreement with estimates from olivine-hosted melt inclusions (Metrich et al., 1991) and depleted MORB mantle (DMM) CO2 source estimates (Marty, 2012). In addition, pre-eruptive CO2 compositions are estimated for individual segments of the Icelandic axial rift zones, and show a marked decrease from north to south (Northern Rift Zone = 550 ± 66 ppm; Eastern Rift Zone = 371 ± 45 ppm; Western Rift Zone = 206 ± 24 ppm). Notably, these results are model dependent, and selection of a lower

  17. An experimental investigation into the feasibility of a thermoelectric heat flux gage

    NASA Technical Reports Server (NTRS)

    Jones, J. C.; Vanfossen, G. J., Jr.

    1981-01-01

    An experiment was conducted to determine the feasibility of using a commerically available thermoelectric device as a heat flux gage. In certain research applications, the thermoelectric heat flux gage can provide a relatively simple means to model a warm fluid--cold wall. The experiment showed that heat flux through the gage could be correlated within two percent to the applied thermoelectric current through the device and the hot and cold side temperature with a simple algebraic equation.

  18. Geothermal Recovery System Using Natural Circulating CO2 as A Heat Transfer Fluid

    NASA Astrophysics Data System (ADS)

    Soma, Hiroshi; Iwasawa, Kenji; Fukumiya, Kenji

    In the conventional system, heat is recovered as sensible heat through liquid anti-freezer circulating in a piping laid underground, but if CO2 is used as a heat transfer fluid, heat is recovered as latent heat which increases the capacity and enables to promote downsize of the equipment and reduction of the electric consumption. It also enables the diameter or the length of heat recovery piping for the same heat exchange performance, thus the installation cost of the piping would be reduced. In our study, a geothermal recovery system using CO2 for air-conditioning was installed, and the heating capacity and the electric consumption were measured. Also, those of a conventional propylene-glycol system were measured. As a result, the CO2-system exerted the same heating ability with the propylene-glycol system with a half length of heat recovery piping and a half electric consumption of the propylene-glycol system. And the reduction in the diameter of the CO2 recovery piping was possible to 50 mm at most to gain more than adequate heating effect.

  19. Description of heat flux measurement methods used in hydrocarbon and propellant fuel fires at Sandia.

    SciTech Connect

    Nakos, James Thomas

    2010-12-01

    The purpose of this report is to describe the methods commonly used to measure heat flux in fire applications at Sandia National Laboratories in both hydrocarbon (JP-8 jet fuel, diesel fuel, etc.) and propellant fires. Because these environments are very severe, many commercially available heat flux gauges do not survive the test, so alternative methods had to be developed. Specially built sensors include 'calorimeters' that use a temperature measurement to infer heat flux by use of a model (heat balance on the sensing surface) or by using an inverse heat conduction method. These specialty-built sensors are made rugged so they will survive the environment, so are not optimally designed for ease of use or accuracy. Other methods include radiometers, co-axial thermocouples, directional flame thermometers (DFTs), Sandia 'heat flux gauges', transpiration radiometers, and transverse Seebeck coefficient heat flux gauges. Typical applications are described and pros and cons of each method are listed.

  20. Low-Temperature Enhanced Geothermal System using Carbon Dioxide as the Heat-Transfer Fluid

    SciTech Connect

    Eastman, Alan D.

    2014-07-24

    This report describes work toward a supercritical CO2-based EGS system at the St. Johns Dome in Eastern Arizona, including a comprehensive literature search on CO2-based geothermal technologies, background seismic study, geological information, and a study of the possible use of metal oxide heat carriers to enhance the heat capacity of sCO2. It also includes cost estimates for the project, and the reasons why the project would probably not be cost effective at the proposed location.

  1. Preliminary study on improvement of cementitious grout thermal conductivity for geothermal heat pump applications

    SciTech Connect

    Allan, M.L.

    1996-06-01

    Preliminary studies were preformed to determine whether thermal conductivity of cementitious grouts used to backfill heat exchanger loops for geothermal heat pumps could be improved, thus improving efficiency. Grouts containing selected additives were compares with conventional bentonite and cement grouts. Significant enhancement of grout alumina grit, steel fibers, and silicon carbide increased the thermal conductivity when compared to unfilled, high solids bentonite grouts and conventional cement grouts. Furthermore, the developed grouts retained high thermal conductivity in the dry state, where as conventional bentonite and cement grouts tend to act as insulators if moisture is lost. The cementitious grouts studied can be mixed and placed using conventional grouting equipment.

  2. Utah State Prison Space Heating with Geothermal Heat Third Semi-Annual Report for the Period January 1981 - July 1981

    SciTech Connect

    1981-11-01

    Facing certain cost overruns and lacking information about the long term productivity of the Crystal Hot Springs geothermal resource, costs of construction for the geothermal retrofit, and the method of disposal of geothermal waste water, the Energy Office embarked on a strategy that would enable the project participants to develop accurate cost information on the State Prison Space Heating Program through the completion of Task 5-Construction. The strategy called for: (1) Completion of the resource assessment to determine whether test well USP/TH-1 could be used as a production well. If well USP/TH-1 was found to have sufficient production capacity, money would not have to be expended on drilling another production well. (2) Evaluation of disposal alternatives and estimation of the cost of each alternative. There was no contingency in the original budget to provide for a reinjection disposal system. Cooperative agreement DE EC07-ET27027 indicated that if a disposal system requiring reinjection was selected for funding that task would be negotiated with DOE and the budget amended accordingly. (3) Completion of the preliminary engineering and design work. Included in this task was a thorough net present value cash flow analysis and an assessment of the technical feasibility of a system retrofit given the production characteristics of well USP/TH-1 . In addition, completion of the preliminary design would provide cost estimates for the construction and commissioning of the minimum security geothermal space heating system. With this information accurate costs for each task would be available, allowing the Energy Office to develop strategies to optimize the use of money in the existing budget to ensure completion of the program. Reported herein is a summary of the work towards the completion of these three objectives conducted during the period of January 1981 through June 1981.

  3. Quantitative method for measuring heat flux emitted from a cryogenic object

    DOEpatents

    Duncan, R.V.

    1993-03-16

    The present invention is a quantitative method for measuring the total heat flux, and of deriving the total power dissipation, of a heat-fluxing object which includes the steps of placing an electrical noise-emitting heat-fluxing object in a liquid helium bath and measuring the superfluid transition temperature of the bath. The temperature of the liquid helium bath is thereafter reduced until some measurable parameter, such as the electrical noise, exhibited by the heat-fluxing object or a temperature-dependent resistive thin film in intimate contact with the heat-fluxing object, becomes greatly reduced. The temperature of the liquid helum bath is measured at this point. The difference between the superfluid transition temperature of the liquid helium bath surrounding the heat-fluxing object, and the temperature of the liquid helium bath when the electrical noise emitted by the heat-fluxing object becomes greatly reduced, is determined. The total heat flux from the heat-fluxing object is determined as a function of this difference between these temperatures. In certain applications, the technique can be used to optimize thermal design parameters of cryogenic electronics, for example, Josephson junction and infrared sensing devices.

  4. Quantitative method for measuring heat flux emitted from a cryogenic object

    DOEpatents

    Duncan, Robert V.

    1993-01-01

    The present invention is a quantitative method for measuring the total heat flux, and of deriving the total power dissipation, of a heat-fluxing object which includes the steps of placing an electrical noise-emitting heat-fluxing object in a liquid helium bath and measuring the superfluid transition temperature of the bath. The temperature of the liquid helium bath is thereafter reduced until some measurable parameter, such as the electrical noise, exhibited by the heat-fluxing object or a temperature-dependent resistive thin film in intimate contact with the heat-fluxing object, becomes greatly reduced. The temperature of the liquid helum bath is measured at this point. The difference between the superfluid transition temperature of the liquid helium bath surrounding the heat-fluxing object, and the temperature of the liquid helium bath when the electrical noise emitted by the heat-fluxing object becomes greatly reduced, is determined. The total heat flux from the heat-fluxing object is determined as a function of this difference between these temperatures. In certain applications, the technique can be used to optimize thermal design parameters of cryogenic electronics, for example, Josephson junction and infra-red sensing devices.

  5. Effects of Temperature Gradients and Heat Fluxes on High-Temperature Oxidation

    SciTech Connect

    Holcomb, G.R.

    2008-04-01

    The effects of a temperature gradient and heat flux on point defect diffusion in protective oxide scales were examined. Irreversible thermodynamics were used to expand Fick’s first law of diffusion to include a heat-flux term—a Soret effect. Oxidation kinetics were developed for the oxidation of cobalt and of nickel doped with chromium. Research is described to verify the effects of a heat flux by oxidizing pure cobalt in a temperature gradient at 900 °C, and comparing the kinetics to isothermal oxidation. No evidence of a heat flux effect was found.

  6. Eustasy, supercontinental insulation, and the temporal variability of terrestrial heat flux

    NASA Astrophysics Data System (ADS)

    Korenaga, Jun

    2007-05-01

    Heat flux from convection in Earth's mantle has recently been suggested to vary substantially (20-30%) with the Wilson cycle of continental aggregation and dispersal, because of possible changes in the aspect ratio of convective cells, and the present-day heat flux may be at the maximum at such a temporal variation. This possibility of strong temporal fluctuations in heat flux has an important bearing on how we should model the thermal evolution of Earth in general. As most of convective heat flux appears as oceanic heat flux, and changes in oceanic heat flux can cause changes in the global sea-level, the likely amplitude of such a temporal variation can be quantified by long-term eustasy. Though this inference may be complicated by other processes that can affect the global sea level, most of them predict sea-level fall when Pangea was present, allowing to place a likely bound on the temporal variability of heat flux. Given the geologically plausible age-area distribution of seafloor, the present-day oceanic heat flux is likely at the minimum (not the maximum) of a possible temporal fluctuation, and the oceanic heat flux at ˜ 200 Ma cannot be lower than today by more than a few percent. I also suggest that mantle warming by supercontinental insulation is probably up to only ˜ 20 K, though it still has a nontrivial consequence for the global sea level.

  7. Tests of a robust eddy correlation system for sensible heat flux

    NASA Astrophysics Data System (ADS)

    Blanford, J. H.; Gay, L. W.

    1992-03-01

    Sensible heat flux estimates from a simple, one-propeller eddy correlation system (OPEC) were compared with those from a sonic anemometer eddy correlation system (SEC). In accordance with similarity theory, the performance of the OPEC system improved with increasing height of the sensor above the surface. Flux totals from the two systems at sites with adequate fetch were in excellent agreement after frequency response corrections were applied. The propeller system appears suitable for long periods of unattended measurement. The sensible heat flux measurements can be combined with net radiation and soil heat flux measurements to estimate latent heat as a residual in the surface energy balance.

  8. PIC Simulation of the Electron Whistler Heat Flux Instability in the Solar Wind

    NASA Astrophysics Data System (ADS)

    Choi, E.; Min, K.; Roberts, D. A.; Hwang, K. J.; Sibeck, D. G.; Dokgo, K.

    2015-12-01

    Electrons in the solar wind are often observed as two distinguishable components; a thermal dense core and a suprathermal halo. The relative drift and anisotropy of these two electron components determine the electron heat flux, which can excite various electromagnetic instabilities. Among these, the whistler has been found to be one of the most commonly-observed and important instabilities. The electron parameters derived from the measured solar wind are comparable to the threshold values predicted by the linear Vlasov theory of the whistler heat flux instability. The enhanced magnetic field fluctuations driven by the heat flux instability, in turn, prevent the drift speed difference between the two populations from increasing. This indicates that the electron heat flux is constrained and regulated by heat flux instabilities through the wave-particle scattering. Such electron heat flux regulation has widely been observed and in best agreement with the whistler heat flux instability. Here we present the growth of the electron heat flux instability in the solar wind condition using 1D PIC simulation with a periodic boundary condition. The two Maxwellian electron components are found to predominantly excite the whistler waves. We examine the growth rates of the whistle instability with respect to various plasma parameters such as the difference in drift speeds between the two components and temperature of the halo, to show the electron heat flux regulation by the whistler.

  9. Modelling Hydraulic and Thermal Responses in a Benchmark for Deep Geothermal Heat Production

    NASA Astrophysics Data System (ADS)

    Holzbecher, E.; Oberdorfer, P.

    2012-04-01

    Geothermal heat production from deep reservoirs (5000-7000 m) is currently examined within the collaborative research program "Geothermal Energy and High-Performance Drilling" (gebo), funded by the Ministry of Science and Culture of Lower Saxony (Germany) and Baker Hughes. The projects concern exploration and characterization of geothermal reservoirs as well as production. They are gathered in the four major topic fields: geosystem, drilling, materials, technical system. We present modelling of a benchmark set-up concerning the geothermal production itself. The benchmark model "Horstberg" was originally created by J. Löhken and is based on geological data, concerning the Horstberg site in Lower Saxony. The model region consists of a cube with a side length of 5 km, in which 13 geological layers are included. A fault zone splits the region into two parts with shifted layering. A well is implemented, reaching from the top to an optional depth crossing all layers including the fault zone. The original geological model was rebuilt and improved in COMSOL Multiphysics Version 4.2a. The heterogeneous and detailed configuration makes the model interesting for benchmarking hydrogeological and geothermal applications. It is possible to inject and pump at any level in the well and to study the hydraulic and thermal responses of the system. The hydraulic and thermal parameters can be varied, and groundwater flow can be introduced. Moreover, it is also possible to examine structural mechanical responses to changes in the stress field (which is not further examined here). The main purpose of the presented study is to examine the dynamical flow characteristics of a hydraulic high conductive zone (Detfurth) in connection to a high conductive fault. One example is the fluid injection in the Detfurth zone and production in the fault. The high conductive domains can provide a hydraulic connection between the well screens and the initiated flow circuit could be used for geothermal

  10. Reference book on geothermal direct use

    SciTech Connect

    Lienau, P.J.; Lund, J.W.; Rafferty, K.; Culver, G.

    1994-08-01

    This report presents the direct uses of geothermal energy in the United States. Topics discussed include: low-temperature geothermal energy resources; energy reserves; geothermal heat pumps; geothermal energy for residential buildings; and geothermal energy for industrial usage.

  11. Geothermal systems

    NASA Technical Reports Server (NTRS)

    Mohl, C.

    1978-01-01

    Several tasks of JPL related to geothermal energy are discussed. The major task is the procurement and test and evaluation of a helical screw drive (wellhead unit). A general review of geothermal energy systems is given. The presentation focuses attention on geothermal reservoirs in California, with graphs and charts to support the discussion. Included are discussions on cost analysis, systems maintenance, and a comparison of geothermal and conventional heating and cooling systems.

  12. The evaluation of a 4000-home geothermal heat pump retrofit at Fort Polk, Louisiana: Final Report

    SciTech Connect

    Hughes, P.J.; Shonder, J.A.

    1998-03-01

    This report documents an independent evaluation of an energy retrofit of 4,003 family housing units at Fort Polk, Louisiana, under an energy savings performance contract (ESPC). Replacement of the heating, cooling, and water heating systems in these housing units with geothermal heat pumps (GHPs) anchored the retrofit; low-flow shower heads and compact fluorescent lighting were also installed, as well as attic insulation where needed. Statistically valid findings indicate that the project will save 25.8 million kWh, or 32.5% of the pre-retrofit whole-community electrical consumption, and 100% of the whole-community natural gas previously used for space conditioning and water heating (260,000 therms) in a typical meteorological year. At the end-use level, the GHPs were found to save about 42% of the pre-retrofit electrical consumption for heating, cooling, and water heating in housing units that were all-electric in the pre-retrofit period. This report also demonstrates an improved method of predicting energy savings. Using an engineering model calibrated to pre-retrofit energy use data collected in the field, the method predicted actual energy savings on one of the electric feeders at Fort Polk with a very high degree of accuracy. The accuracy of this model was in turn dependent on data-calibrated models of the geothermal heat pump and ground heat exchanger that are described in this report. In addition this report documents the status of vertical borehole ground heat exchanger (BHEx) design methods at the time this project was designed, and demonstrates methods of using data collected from operating GHP systems to benchmark BHEx design methods against a detailed engineering model calibrated to date. The authors also discuss the ESPC`s structure and implementation and how the experience gained here can contribute to the success of future ESPCs.

  13. Soil Microbial Community Structure across a Thermal Gradient following a Geothermal Heating Event

    PubMed Central

    Norris, Tracy B.; Wraith, Jon M.; Castenholz, Richard W.; McDermott, Timothy R.

    2002-01-01

    In this study microbial species diversity was assessed across a landscape in Yellowstone National Park, where an abrupt increase in soil temperature had occurred due to recent geothermal activity. Soil temperatures were measured, and samples were taken across a temperature gradient (35 to 65°C at a 15-cm depth) that spanned geothermally disturbed and unimpacted soils; thermally perturbed soils were visually apparent by the occurrence of dead or dying lodgepole pine trees. Changes in soil microbial diversity across the temperature gradient were qualitatively assessed based on 16S rRNA sequence variation as detected by denaturing gradient gel electrophoresis (DGGE) using both ribosomal DNA (rDNA) and rRNA as PCR templates and primers specific for the Bacteria or Archaea domain. The impact of the major heating disturbance was apparent in that DGGE profiles from heated soils appeared less complex than those from the unaffected soils. Phylogenetic analysis of a bacterial 16S rDNA PCR clone library from a recently heated soil showed that a majority of the clones belonged to the Acidobacterium (51%) and Planctomyces (18%) divisions. Agar plate counts of soil suspensions cultured on dilute yeast extract and R2A agar media incubated at 25 or 50°C revealed that thermophile populations were two to three orders of magnitude greater in the recently heated soil. A soil microcosm laboratory experiment simulated the geothermal heating event. As determined by both RNA- and DNA-based PCR coupled with DGGE, changes in community structure (marked change in the DGGE profile) of soils incubated at 50°C occurred within 1 week and appeared to stabilize after 3 weeks. The results of our molecular and culture data suggest that thermophiles or thermotolerant species are randomly distributed in this area within Yellowstone National Park and that localized thermal activity selects for them. PMID:12450855

  14. Correlations of Nucleate Boiling Heat Transfer and Critical Heat Flux for External Reactor Vessel Cooling

    SciTech Connect

    J. Yang; F. B. Cheung; J. L. Rempe; K. Y. Suh; S. B. Kim

    2005-07-01

    Four types of steady-state boiling experiments were conducted to investigate the efficacy of two distinctly different heat transfer enhancement methods for external reactor vessel cooling under severe accident conditions. One method involved the use of a thin vessel coating and the other involved the use of an enhanced insulation structure. By comparing the results obtained in the four types of experiments, the separate and integral effect of vessel coating and insulation structure were determined. Correlation equations were obtained for the nucleate boiling heat transfer and the critical heat flux. It was found that both enhancement methods were quite effective. Depending on the angular location, the local critical heat flux could be enhanced by 1.4 to 2.5 times using vessel coating alone whereas it could be enhanced by 1.8 to 3.0 times using an enhanced insulation structure alone. When both vessel coating and insulation structure were used simultaneously, the integral effect on the enhancement was found much less than the product of the two separate effects, indicating possible competing mechanisms (i.e., interference) between the two enhancement methods.

  15. Understanding of flux-limited behaviors of heat transport in nonlinear regime

    NASA Astrophysics Data System (ADS)

    Guo, Yangyu; Jou, David; Wang, Moran

    2016-01-01

    The classical Fourier's law of heat transport breaks down in highly nonequilibrium situations as in nanoscale heat transport, where nonlinear effects become important. The present work is aimed at exploring the flux-limited behaviors based on a categorization of existing nonlinear heat transport models in terms of their theoretical foundations. Different saturation heat fluxes are obtained, whereas the same qualitative variation trend of heat flux versus exerted temperature gradient is got in diverse nonlinear models. The phonon hydrodynamic model is proposed to act as a standard to evaluate other heat flux limiters because of its more rigorous physical foundation. A deeper knowledge is thus achieved about the phenomenological generalized heat transport models. The present work provides deeper understanding and accurate modeling of nonlocal and nonlinear heat transport beyond the diffusive limit.

  16. Thermal response to the surface heat flux in a macrotidal coastal region (Nuevo Gulf, Argentina)

    NASA Astrophysics Data System (ADS)

    Rivas, Andrés L.; Pisoni, Juan P.; Dellatorre, Fernando G.

    2016-07-01

    At mid-latitudes, sea water temperature shows a strong seasonal cycle forced by the incident surface heat flux. As depth decreases, the heat flux incidence is damped by the horizontal flux, which prevents the indefinite growth of the seasonal temperature range. In the present work, cross-shore transport in the west coast of Nuevo Gulf (Argentina) was analyzed. Processes tending to cool the coastal waters in summer and to warm the coastal waters in winter, were identified through temperature measurements, surface heat flux and tidal height. The simplified models proposed here provide a feedback mechanism that links changes in surface heat flux with changes in the horizontal heat flux during both seasons. On shorter time scales, tide produces significant variations in the height of the water column, therefore influencing temperature fluctuations and the direction of the horizontal flow.

  17. Design and construction of the NMSU Geothermally Heated Greenhouse Research Facility: Final technical report

    SciTech Connect

    Schoenmackers, R.

    1988-11-01

    This report describes the design, construction, and performance of the New Mexico State University (NMSU) Geothermal Greenhouse Research Facility. Two 6000-square-foot greenhouses were built on the NMSU campus and supplied with geothermal energy for heating. The geothermal water is pumped from one of three wells producing water at temperatures from 141/degree/F to 148/degree/F. Heat is delivered to the greenhouse space by means of overhead fan-coil unit heaters. The two greenhouses are double-glazed on roof and wall surfaces employing a total of four different film materials: Tedlar/Reg Sign/, Melinex/Reg Sign/, Softglass/Reg Sign/, and Agrifilm/Reg Sign/. One greenhouse is cooled using a traditional fan and pad cooling system. The second greenhouse is cooled with a high-pressure fog system and natural ventilation through roof and side vents. A 2400-square-foot metal building next to the greenhouses provides office, work, and storage space for the facility. The greenhouse facility was leased to two commerical tenants who produced a variety of crops. The performance of the greenhouses was monitored and reported both qualitatively and quantitatively. Results from the tenant's pilot-scale studies in the NMSU greenhouse facility were transferred and applied to two commercial greenhouse ranges that were built in southern New Mexico during 1986/87. 9 figs., 5 tabs.

  18. Geothermal direct heat use: Market potential/penetration analysis for Federal Region 9

    NASA Technical Reports Server (NTRS)

    Powell, W. (Editor); Tang, K. (Editor)

    1980-01-01

    A preliminary study was made of the potential for geothermal direct heat use in Arizona, California, Hawaii, and Nevada (Federal Region 9). An analysis was made of each state to: (1) define the resource, based on the latest available data; (2) assess the potential market growth for geothermal energy; and (3) estimate the market penetration, projected to 2020. Findings of the study include the following: (1) Potentially economical hydrothermal resources exist in all four states of the Region: however, the resource data base is largely incomplete, particularly for low to moderate temperature resources. (2) In terms of beneficial heat, the total hydrothermal resource identified so far for the four states is on the order of 43 Quads, including an estimated 34 Quads of high temperature resources which are suitable for direct as well as electrical applications. (3) In California, Hawaii, and Nevada, the industrial market sector has somewhat greater potential for penetration than the residential/commercial sector. In Arizona, however, the situation is reversed, due to the collocation of two major metropolitan areas (Phoenix and Tucson) with potential geothermal resources.

  19. Heat Flux From the Endeavour Segment of the Juan de Fuca Ridge

    NASA Astrophysics Data System (ADS)

    Thompson, W. J.; McDuff, R. E.; Stahr, F. R.; Yoerger, D. R.; Jakuba, M.

    2005-12-01

    The very essence of a hydrothermal system is transfer of heat by a convecting fluid, yet the flux of heat remains a poorly known quantity. Past studies of heat flux consisted primarily of point measurements of temperature and fluid flow at individual vent sites and inventories of the neutrally buoyant plume above the field. In 2000 the Flow Mow project used the Autonomous Benthic Explorer (ABE) to determine heat flux from Main Endeavour Field (MEF) on the Juan de Fuca Ridge by intersecting the stems of rising buoyant plumes. ABE carries instruments to measure conductivity, temperature and depth, and a MAVS current meter to determine the vertical velocity of the fluid, after correcting for vehicle motion. Complementary work on horizontal fluxes suggests that the vertical flux measured by ABE includes both the primary high buoyancy focused "smoker" sources and also entrained diffuse flow. In 2004, ABE was again used to determine heat flux not only from MEF, but also from the other four fields in the Endeavour Segment RIDGE 2000 Integrated Study Site. In this four year interval the flux of heat from MEF has declined by approximately a factor of two. The High Rise vent field has the greatest heat flux, followed by MEF, then Mothra, Salty Dawg and Sasquatch (of order 500, 300, 100, 50 MW respectively; heat flux at Sasquatch was below detection).

  20. Geothermal Technologies Program: Utah

    SciTech Connect

    Not Available

    2005-06-01

    Geothermal Technologies Program Utah fact sheet describes the geothermal areas and use in Utah, focusing on power generation as well as direct use, including geothermally heated greenhouses, swimming pools, and therapeutic baths.

  1. Satellite estimates of ocean-air heat fluxes during cold air outbreaks

    NASA Technical Reports Server (NTRS)

    Chou, S.-H.; Atlas, D.

    1982-01-01

    A method for estimating the heat and moisture fluxes of coastal waters using the cloud free path, the sea surface temperature, and the saturation water vapor mixing ratio is presented. Generalized nomograms for the surface sensible and latent heat fluxes are developed using the Stage and Businger (1981) mixed-layer model. The fluxes are found to be slightly dependent on wind speed. The results are found to be applicable to any path within the cloud-free region, with heat fluxes obtainable by multiplication of the mean heating by the mean wind speed in the boundary layer. Higher stability causes lowered heating. It is shown that the latent heat flux is linear. Applications of the method to lake-effect snowstorms and for verification of boundary-layer models are indicated.

  2. Method for evaluating the potential of geothermal energy in industrial process heat applications

    SciTech Connect

    Packer, M.B.; Mikic, B.B.; Meal, H.C., Guillamon-Duch, H.

    1980-05-01

    A method is presented for evaluating the technical and economic potential of geothermal energy for industrial process heat applications. The core of the method is a computer program which can be operated either as a design analysis tool to match energy supplies and demands, or as an economic analysis tool if a particular design for the facility has already been selected. Two examples are given to illustrate the functioning of the model and to demonstrate that results reached by use of the model closely parallel those that have been determined by more traditional techniques. Other features of interest in the model include: (1) use of decision analysis techniques as well as classical methods to deal with questions relating optimization; (2) a tax analysis of current regulations governing percentage depletion for geothermal deposits; and (3) development of simplified correlations for the thermodynamic properties of salt solutions in water.

  3. TOUGH2 grid generator for simulations of geothermal heat pump systems

    NASA Astrophysics Data System (ADS)

    Kim, Seong-Kyun; Bae, Gwang-Ok; Lee, Kang-Kun

    2015-04-01

    We present a method to generate an unstructured Voronoi grid for its use in TOUGH2 simulations of geothermal heat pump systems. A series of codes is developed to create Voronoi cell center points that are placed at specific positions for well- or pipe-shaped Voronoi grids, to generate a three-dimensional grid and TOUGH2 input files from generated Voronoi cell vertices, and to visualize the generated grid and simulation results by ParaView. AMESH program is used to calculate the x- and y-coordinates of the Voronoi cell vertices from the Voronoi cell center points. We show the desired form of grid from the developed series of codes and test with confidence the presented method through simulations of water production/injection from/to the various kinds of the geothermal wells.

  4. Possibilities of using carbon dioxide as fillers for heat pipe to obtain low-potential geothermal energy

    NASA Astrophysics Data System (ADS)

    Kasanický, M.; Gavlas, S.; Vantúch, M.; Malcho, M.

    2013-04-01

    The use of low-potential heat is now possible especially in systems using heat pumps. There is a presumption that the trend will continue. Therefore, there is a need to find ways to be systems with a heat pump efficiencies. The usage of heat pipes seems to be an appropriate alternative to the establishedtechnology of obtaining heat through in-debt probes. This article describes a series of experiments on simulator for obtaining low-potential geothermal energy, in order to find the optimal amount of carbon dioxide per meter length of the heat pipe. For orientation and understanding of the conclusions of theexperiment, the article has also a detailed description of the device which simulates the transport of heat through geothermal heat pipes.

  5. Thermodynamic and thermoeconomic analysis of combined geothermal space heating and thermal storage using phase change materials

    NASA Astrophysics Data System (ADS)

    Chauhan, V.; Ragnarsson, Á.

    2015-12-01

    The present work discusses the utilization of phase change materials for energy storage in geothermal space heating systems. Thermodynamics and thermoeconomics of the combined heating and thermal storing system were studied to show the scope of energy storage and cost savings. A computational model of the combined space heating and thermal storage system was developed and used to perform thermodynamic studies of the heat storage process and heating system efficiency at different times and ambient temperatures. The basis for these studies is daily variations in heating demand that is higher during the night than during the day. The results show the scope of the utilization of phase change material for low ambient temperature conditions. Under proper conditions a sufficient amount of exergy is stored during the charging period at a low ambient temperature to fulfill the daytime heat load requirement. Under these conditions the cost flow rate of exergy storage is found to be lower than the radiator heating cost flow rate. Thus, the use of exergy storage at low ambient temperatures for heating at higher ambient temperatures makes a significant contribution to cost savings.

  6. Correlation of critical heat flux data for uniform tubes

    SciTech Connect

    Jafri, T.; Dougherty, T.J.; Yang, B.W.

    1995-09-01

    A data base of more than 10,000 critical heat flux (CHF) data points has been compiled and analyzed. Two regimes of CHF are observed which will be referred to as the high CHF regime and the low CHF regime. In the high CHF regime, for pressures less than 110 bar, CHF (q{sub c}) is a determined by local conditions and is adequately represented by q{sub c} = (1.2/D{sup 1/2}) exp[-{gamma}(GX{sub t}){sup 1/2}] where the parameter {gamma} is an increasing function of pressure only, X{sub t} the true mass fraction of steam, and all units are metric but the heat flux is in MWm{sup -2}. A simple kinetic model has been developed to estimate X{sub t} as a function of G, X, X{sub i}, and X{sub O}, where X{sub i} is the inlet quality and X{sub O} represents the quality at the Onset of Significant Vaporization (OSV) which is estimated from the Saha-Zuber (S-Z) correlation. The model is based on a rate equation for vaporization suggested by, and consistent with, the S-Z correlation and contains no adjustable parameters. When X{sub i}X{sub O}, X{sub t} depends on X{sub i}, a nonlocal variable, and, in this case, CHF, although determined by local conditions, obeys a nonlocal correlation. This model appears to be satisfactory for pressures less than 110 bar, where the S-Z correlation is known to be reliable. Above 110 bar the method of calculating X{sub O}, and consequently X{sub t}, appears to fail, so this approach can not be applied to high pressure CHF data. Above 35 bar, the bulk of the available data lies in the high CHF regime while, at pressures less than 35 bar, almost all of the available data lie in the low CHF regime and appear to be nonlocal.

  7. Development of a Deep-Penetrating, Compact Geothermal Heat Flow System for Robotic Lunar Geophysical Missions

    NASA Technical Reports Server (NTRS)

    Nagihara, Seiichi; Zacny, Kris; Hedlund, Magnus; Taylor, Patrick T.

    2012-01-01

    Geothermal heat flow measurements are a high priority for the future lunar geophysical network missions recommended by the latest Decadal Survey of the National Academy. Geothermal heat flow is obtained as a product of two separate measurements of geothermal gradient and thermal conductivity of the regolith/soil interval penetrated by the instrument. The Apollo 15 and 17 astronauts deployed their heat flow probes down to 1.4-m and 2.3-m depths, respectively, using a rotary-percussive drill. However, recent studies show that the heat flow instrument for a lunar mission should be capable of excavating a 3-m deep hole to avoid the effect of potential long-term changes of the surface thermal environment. For a future robotic geophysical mission, a system that utilizes a rotary/percussive drill would far exceed the limited payload and power capacities of the lander/rover. Therefore, we are currently developing a more compact heat flow system that is capable of 3-m penetration. Because the grains of lunar regolith are cohesive and densely packed, the previously proposed lightweight, internal hammering systems (the so-called moles ) are not likely to achieve the desired deep penetration. The excavation system for our new heat flow instrumentation utilizes a stem which winds out of a pneumatically driven reel and pushes its conical tip into the regolith. Simultaneously, gas jets, emitted from the cone tip, loosen and blow away the soil. Lab tests have demonstrated that this proboscis system has much greater excavation capability than a mole-based heat flow system, while it weighs about the same. Thermal sensors are attached along the stem and at the tip of the penetrating cone. Thermal conductivity is measured at the cone tip with a short (1- to 1.5-cm long) needle sensor containing a resistance temperature detector (RTD) and a heater wire. When it is inserted into the soil, the heater is activated. Thermal conductivity of the soil is obtained from the rate of temperature

  8. Analysis of induced seismicity and heat transfer in geothermal reservoirs by coupled simulation

    NASA Astrophysics Data System (ADS)

    Gan, Quan

    Massive water injection during the stimulation and production stages in geothermal reservoirs is able to induce strong coupled response. Fracture properties may be significantly altered due to fluid transport, heat transfer, and chemical reactions. The constitutive relationships governing the transport of mass, heat, deformation, and chemical reaction are defined by various parameters, including permeability, porosity, temperature, and local stress state. One of the purposes of this study is to investigate the principal factors including the thermal, hydraulic, and mechanical effects in inducing the reactivation of pre-existing fractures. The seismicity induced from the reactivation of fractures and faults is influenced and triggered by different processes at different length and timescales. We explore these effects related to the timing of seismicity and the roles or effective stresses and thermal stresses in fractured reservoirs including the use of reactivation to control permeability evolution in a manner beneficial to thermal recovery in EGS reservoirs. This dissertation comprises four chapters and an appendix. In Chapter 1 we explore the propagation of fluid pressures and thermal stresses in a prototypical geothermal reservoir containing a centrally-located critically-stressed fault from a doublet injector and withdrawal well to define the likelihood, timing and magnitude of events triggered by both fluid pressures and thermal stresses. We define two bounding modes of fluid production from the reservoir. For injection at a given temperature, these bounding modes relate to either low- or high-relative flow rates. At low relative dimensionless flow rates the pressure pulse travels slowly, the pressure-driven changes in effective stress are muted, but thermal drawdown propagates through the reservoir as a distinct front. This results in the lowest likelihood of pressure-triggered events but the largest likelihood of late-stage thermally-triggered events

  9. Geothermal as a heat sink application for raising air conditioning efficency

    NASA Astrophysics Data System (ADS)

    Ibrahim, Hesham Safwat Osman Mohamed

    2016-04-01

    Objective: Geothermal applications in heating, ventilation, air-conditioning is a US technology for more than 30 years old ,which saves more than 30% average energy cost than the traditional air-conditioning systems systems. Applying this technology in Middle East and African countries would be very feasible specially in Egypt specially as it suffers Electric crisis --The temperature of the condensers and the heat rejecting equipment is much higher than the Egyptian land at different depth which is a great advantages, and must be measured, recorded, and studied accurately -The Far goal of the proposal is to construct from soil analysis a temperature gradient map for Egypt and , African countries on different depth till 100 m which is still unclear nowadays and must be measured and recorded in databases through researches - The main model of the research is to study the heat transfer gradient through the ground earth borehole,grout,high density polyethylene pipes , and water inlet temperature which affect the electric efficiency of the ground source heat pump air conditioning unit Impact on the Region: Such research result will contribute widely in Energy saving sector specially the air conditioning sector in Egypt and the African countries which consumes more than 30% of the electric consumption of the total consumption . and encouraging Green systems such Geothermal to be applied

  10. Experimental and Numerical Characterization of High Heat Fluxes During Transient Blackbody Calibrations

    NASA Technical Reports Server (NTRS)

    Abdelmessih, Amanie N.; Horn, Thomas J.

    2008-01-01

    High heat fluxes are encountered in numerous applications, such as hypersonic vehicles in flight, fires, and engines, Calibration of heat flux gages may be performed in a dual cavity cylindrical blackbody resulting in a transient calibration environment. To characterize the transient heat fluxes. experiments were performed on a dual cavity cylindrical blackbody at nominal temperatures varying from 800 C to 1900 C in increments of 100 C. Based on experiments, the optimum heat flux sensor insertion location as measured from the center partition was determined. The pre-insertion steady state axial temperature profile is compared experimentally, numerically, and analytically. The effect of convection in the blackbody cavity during the insertion is calculated and found to be less than 2 per cent. Also, an empirical correlation for predicting the emissivity of the blackbody is included. Detailed transient thermal models have been developed to simulate the heat flux calibration process at two extreme fluxes. The high (1MW/sq m) and relatively low (70 kw/sq m) fluxes are reported in this article. The transient models show the effect of inserting a heat flux gage at room temperature on the thermal equilibrium of the blackbody at 1800 C and 800 C nominal temperatures, respectively. Also, heat flux sensor outputs are derived from computed sensor temperature distributions and compared to experimental results.

  11. The Role of the Velocity Gradient in Laminar Convective Heat Transfer through a Tube with a Uniform Wall Heat Flux

    ERIC Educational Resources Information Center

    Wang, Liang-Bi; Zhang, Qiang; Li, Xiao-Xia

    2009-01-01

    This paper aims to contribute to a better understanding of convective heat transfer. For this purpose, the reason why thermal diffusivity should be placed before the Laplacian operator of the heat flux, and the role of the velocity gradient in convective heat transfer are analysed. The background to these analyses is that, when the energy…

  12. Numerical modeling of geothermal heat pump system: evaluation of site specific groundwater thermal impact

    NASA Astrophysics Data System (ADS)

    Pedron, Roberto; Sottani, Andrea; Vettorello, Luca

    2014-05-01

    A pilot plant using a geothermal open-loop heat pump system has been realized in the city of Vicenza (Northern Italy), in order to meet the heating and cooling needs of the main monumental building in the historical center, the Palladian Basilica. The low enthalpy geothermal system consists of a pumping well and a reinjection well, both intercepting the same confined aquifer; three other monitoring wells have been drilled and then provided with water level and temperature dataloggers. After about 1 year and a half of activity, during a starting experimental period of three years, we have now the opportunity to analyze long term groundwater temperature data series and to evaluate the numerical modeling reliability about thermal impact prediction. The initial model, based on MODFLOW and SHEMAT finite difference codes, has been calibrated using pumping tests and other field investigations data, obtaining a valid and reliable groundwater flow simulation. But thermal parameters, such as thermal conductivity and volumetric heat capacity, didn't have a site specific direct estimation and therefore they have been assigned to model cells referring to bibliographic standards, usually derived from laboratory tests and barely representing real aquifer properties. Anyway preliminary heat transport results have been compared with observed temperature trends, showing an efficient representation of the thermal plume extension and shape. The ante operam simulation could not consider heat pump real utilization, that happened to be relevantly different from the expected project values; so the first numerical model could not properly simulate the groundwater temperature evolution. Consequently a second model has been implemented, in order to calibrate the mathematical simulation with monitored groundwater temperature datasets, trying to achieve higher levels of reliability in heat transport phenomena interpretation. This second step analysis focuses on aquifer thermal parameters

  13. The validation of ocean surface heat fluxes in AMIP

    SciTech Connect

    Gleckler, P.J.; Randall, D.A.

    1993-09-01

    Recent intercomparisons of Atmospheric General Circulation Models (AGCMS) constrained with sea-surface temperatures have shown that while there are substantial differences among various models (with each other and available observations), overall the differences between them have been decreasing. The primary goal of AMIP is to enable a systematic intercomparison and validation of state-of-the- art AGCMs by supporting in-depth diagnosis of and interpretation of the model results. Official AMIP simulations are 10 years long, using monthly mean Sea-Surface Temperatures (SSTs) and sea ice conditions which are representative of the 1979--1988 decade. Some model properties are also dictated by the design of AMIP such as the solar constant, the atmospheric CO{sub 2} concentration, and the approximate horizontal resolution. In this paper, some of the preliminary results of AMIP Subproject No. 5 will be summarized. The focus will be on the intercomparison and validation of ocean surface heat fluxes of the AMIP simulations available thus far.

  14. Dispersion of Heat Flux Sensors Manufactured in Silicon Technology

    PubMed Central

    Ziouche, Katir; Lejeune, Pascale; Bougrioua, Zahia; Leclercq, Didier

    2016-01-01

    In this paper, we focus on the dispersion performances related to the manufacturing process of heat flux sensors realized in CMOS (Complementary metal oxide semi-conductor) compatible 3-in technology. In particular, we have studied the performance dispersion of our sensors and linked these to the physical characteristics of dispersion of the materials used. This information is mandatory to ensure low-cost manufacturing and especially to reduce production rejects during the fabrication process. The results obtained show that the measured sensitivity of the sensors is in the range 3.15 to 6.56 μV/(W/m2), associated with measured resistances ranging from 485 to 675 kΩ. The dispersions correspond to a Gaussian-type distribution with more than 90% determined around average sensitivity Se¯ = 4.5 µV/(W/m2) and electrical resistance R¯ = 573.5 kΩ within the interval between the average and, more or less, twice the relative standard deviation. PMID:27294929

  15. Dispersion of Heat Flux Sensors Manufactured in Silicon Technology.

    PubMed

    Ziouche, Katir; Lejeune, Pascale; Bougrioua, Zahia; Leclercq, Didier

    2016-01-01

    In this paper, we focus on the dispersion performances related to the manufacturing process of heat flux sensors realized in CMOS (Complementary metal oxide semi-conductor) compatible 3-in technology. In particular, we have studied the performance dispersion of our sensors and linked these to the physical characteristics of dispersion of the materials used. This information is mandatory to ensure low-cost manufacturing and especially to reduce production rejects during the fabrication process. The results obtained show that the measured sensitivity of the sensors is in the range 3.15 to 6.56 μV/(W/m²), associated with measured resistances ranging from 485 to 675 kΩ. The dispersions correspond to a Gaussian-type distribution with more than 90% determined around average sensitivity S e ¯ = 4.5 µV/(W/m²) and electrical resistance R ¯ = 573.5 kΩ within the interval between the average and, more or less, twice the relative standard deviation. PMID:27294929

  16. Heat flux in a penetrative convection experiment in water

    NASA Astrophysics Data System (ADS)

    Corre, Yoann; Alboussière, Thierry; Labrosse, Stéphane; Odier, Philippe; Joubaud, Sylvain

    2015-11-01

    In geophysical systems, stably stratified fluids adjacent to convective regions often experience thermal plume penetration from the latter. This penetrative convection occurs in stellar interiors between radiative and convective regions and possibly in liquid envelopes of planets, such as the Earth's core. We are interested in quantifying this process experimentally as it could play a crucial role in their dynamics. A volume of water initially at ambiant temperature is cooled from below at 0 degrees Celsius. Due to the maximum density of water near 4 degrees, a convective region develops and grows below a purely conductive region. A laser sheet crosses the experimental cell, lightening both neutrally buoyant particles and a thermosensitive fluorescent dye, which allows to monitor the velocity and temperature fields respectively (PIV-LIF technique), giving access to the local convective and conductive heat flux. The apparatus is placed on a rotating table to inspect the effect of the Coriolis force on the interfacial region. We find that increasing the rotation rate deepens the penetration of vortices into the conductive region, thus changing the structure of the interfacial layer and possibly eroding the stable region.

  17. Comparative Calibration of Heat Flux Sensors in Two Blackbody Facilities

    PubMed Central

    Murthy, A. V.; Tsai, B. K.; Saunders, R. D.

    1999-01-01

    This paper presents the results of heat flux sensor calibrations in two blackbody facilities: the 25 mm variable temperature blackbody (VTBB) primary facility and a recently developed 51 mm aperture spherical blackbody (SPBB) facility. Three Schmidt-Boelter gages and a Gardon gage were calibrated with reference to an electrical substitution radiometer in the VTBB. One of the Schmidt-Boelter gages thus calibrated was used as a reference standard to calibrate other gages in the SPBB. Comparison of the Schmidt-Boelter gages calibrations in the SPBB and the VTBB agreed within the measurement uncertainties. For the Gardon gage, the measured responsivity in the SPBB showed a gradual decrease with increasing distance from the aperture. When the gage was located close to the aperture, a distance less than the aperture radius, the responsivity in the SPBB agreed with VTBB measurements. At a distance of about three times the aperture radius, the responsivity showed a decrease of about 4 %. This is probably due to higher convection loss from the Gardon gage surface compared to the Schmidt-Boelter sensor.

  18. 16 CFR Figure 8 to Subpart A of... - Standard Radiant Heat Energy Flux Profile

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 2 2013-01-01 2013-01-01 false Standard Radiant Heat Energy Flux Profile 8 Figure 8 to Subpart A of Part 1209 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER..., Subpt. A, Fig. 8 Figure 8 to Subpart A of Part 1209—Standard Radiant Heat Energy Flux Profile...

  19. 16 CFR Figure 8 to Subpart A of... - Standard Radiant Heat Energy Flux Profile

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 2 2012-01-01 2012-01-01 false Standard Radiant Heat Energy Flux Profile 8 Figure 8 to Subpart A of Part 1209 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER..., Subpt. A, Fig. 8 Figure 8 to Subpart A of Part 1209—Standard Radiant Heat Energy Flux Profile...

  20. 16 CFR Figure 8 to Subpart A of... - Standard Radiant Heat Energy Flux Profile

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 16 Commercial Practices 2 2014-01-01 2014-01-01 false Standard Radiant Heat Energy Flux Profile 8 Figure 8 to Subpart A of Part 1209 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER..., Subpt. A, Fig. 8 Figure 8 to Subpart A of Part 1209—Standard Radiant Heat Energy Flux Profile...

  1. 16 CFR Figure 8 to Subpart A of... - Standard Radiant Heat Energy Flux Profile

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Standard Radiant Heat Energy Flux Profile 8 Figure 8 to Subpart A of Part 1209 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER..., Subpt. A, Fig. 8 Figure 8 to Subpart A of Part 1209—Standard Radiant Heat Energy Flux Profile...

  2. 16 CFR Figure 8 to Subpart A of... - Standard Radiant Heat Energy Flux Profile

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 2 2011-01-01 2011-01-01 false Standard Radiant Heat Energy Flux Profile 8 Figure 8 to Subpart A of Part 1209 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION CONSUMER..., Subpt. A, Fig. 8 Figure 8 to Subpart A of Part 1209—Standard Radiant Heat Energy Flux Profile...

  3. A constitutive function for the heat flux in short-fiber-reinforced composites

    NASA Astrophysics Data System (ADS)

    Herrmann, Heiko

    2015-12-01

    A constitutive function for heat flux in short-fiber-reinforced composites is developed. The fiber orientation distribution is considered using second-order orientation tensor; therefore, the constitutive function for the heat flux will depend on the orientation tensor. The resulting orthotropic equation is discussed also in the context of energy efficiency of buildings.

  4. Regulation of the solar wind electron heat flux from 1 to 5 AU: Ulysses observations

    SciTech Connect

    Scime, E.E.; Bame, S.J.; Feldman, W.C.; Gary, S.P.; Phillips, J.L.; Balogh, A.

    1994-12-01

    In this study the authors use observations from the three-dimensional electron spectrometer and magnetometer aboard the Ulysses spacecraft to examine the solar wind electron heat flux from 1.2 to 5.4 AU in the ecliptic plane. Throughout Ulysses` transit to 5.4 AU, the electron heat flux decreases more rapidly ({approximately}R{sup {minus}3.0}) than simple collisionless expansion along the local magnetic field and is smaller than expected for a thermal gradient heat flux, q{sub {parallel}}e(r)={minus}k{sub {parallel}}{del}{sub {parallel}}T{sub e}(r). The radial gradients and magnitudes expected for a number of electron heat flux regulatory mechanisms are examined and compared to the observations. The best agreement is found for heat flux regulation by the whistler heat flux instability. The upper bound and radial scaling for the electron heat flux predicted for the whistler heat flux instability are consistent with observations.

  5. Empirical models of the eddy heat flux and vertical shear on short time scales

    NASA Technical Reports Server (NTRS)

    Ghan, S. J.

    1984-01-01

    An intimate relation exists between the vertical shear and the horizontal eddy heat flux within the atmosphere. In the present investigation empirical means are employed to provide clues concerning the relationship between the shear and eddy heat flux. In particular, linear regression models are applied to individual and joint time series of the shear and eddy heat flux. These discrete models are used as a basis to infer continuous models. A description is provided of the observed relationship between the flux and the shear, taking into account means, standard deviations, and lag correction functions.

  6. High heat flux sensor for infrared thermography determination of heat transfer coefficient of liquid metal cooled target's wall

    NASA Astrophysics Data System (ADS)

    Patorski, Jacek A.; Gindrat, Malko

    2009-05-01

    The proton beam passing through the wall area of a liquid metal (LM) target container, called entrance window, is causing deposition of maximum high heat flux amount 140 W/cm2.Previous experimental thermo-hydraulics investigations for the MEGAPIE LM-target at the SINQ facility of Heat- Transfer-Coefficient (HTC) using InfraRed-Thermography (IRT) have been presented at Thermosense 2006 and 2007 [1], [2] and references therein. During these investigations the IRT active sensors with applied heat fluxes of the small and low range from 2.5 to 15.2 W/cm2 are used. The heating shell foil of the sensor has been connected to steel dish enclosing LM target container by using electrical insulation ceramic glue. A higher, then achieved 15 W/cm2, heat flux has lead to delaminating of the heater. Because of interest to determinate the HTC-chart under real heat flux conditions and investigate some positive effect of heat flux buoyancy on cooling, the idea for the High Heat Flux (HHF) IRT Sensors, using of the Low Pressure Plasma Spraying - Thin Film (LPPS-TF) technology of the Sulzer Metco Company has been created. The paper presents the idea of multilayer thermal sprayed construction of HHF-IRT-Sensor, few realizations and some results of the first pre-test performed at the PSI LBE Double Pump Loop using the new sensor and the 2DD IRT methodology presented in [1].

  7. Comparison of measured and modeled radiation, heat and water vapor fluxes: FIFE pilot study

    NASA Technical Reports Server (NTRS)

    Blad, Blaine L.; Hubbard, Kenneth G.; Verma, Shashi B.; Starks, Patrick; Norman, John M.; Walter-Shea, Elizabeth

    1987-01-01

    The feasibility of using radio frequency receivers to collect data from automated weather stations to model fluxes of latent heat, sensible heat, and radiation using routine weather data collected by automated weather stations was tested and the estimated fluxes were compared with fluxes measured over wheat. The model Cupid was used to model the fluxes. Two or more automated weather stations, interrogated by radio frequency and other means, were utilized to examine some of the climatic variability of the First ISLSCP (International Satellite Land-Surface Climatology Project) Field Experiment (FIFE) site, to measure and model reflected and emitted radiation streams from various locations at the site and to compare modeled latent and sensible heat fluxes with measured values. Some bidirectional reflected and emitted radiation data were collected from 23 locations throughout the FIFE site. Analysis of these data along with analysis of the measured sensible and latent heat fluxes is just beginning.

  8. Pressure and heat flux effects on the heat transfer characteristics of liquid methane

    NASA Astrophysics Data System (ADS)

    Garcia, Chance P.

    The heat transfer effects on liquid methane are investigated with the use of a carbo-thermal rig at the Center for Space Exploration Technology Research (cSETR) located at the University of Texas at El Paso (UTEP). The cSETR carbo-thermal rig design approach is presented along with the design of a methane condensing mobile unit (MCMU) to supply the laboratory and rig with liquid methane. The proposed research will generate useful insight in to heat transfer coefficient behavior, non-dimensional correlations, different flow conditions, varied inlet conditions, and varied heat flux for a subscale test article applicable to a regenerative cooled rocket engine cooling channel. The data found will also improve the knowledge base for liquid methane and non-toxic propulsion. Planned test parameters are from 1.03 to 2.07 MPa (150 to 300 psi) supply tank pressure, and 3.9 to 19 MW/m2 (2.39 to 11.6 Btu/in2-s). Presented are transient and steady state heat transfer response results depicting transient and steady state heat transfer effects tested at turbulent Reynolds numbers (15000 to 360000).

  9. Time and Space Resolved Heat Transfer Measurements Under Nucleate Bubbles with Constant Heat Flux Boundary Conditions

    NASA Technical Reports Server (NTRS)

    Myers, Jerry G.; Hussey, Sam W.; Yee, Glenda F.; Kim, Jungho

    2003-01-01

    Investigations into single bubble pool boiling phenomena are often complicated by the difficulties in obtaining time and space resolved information in the bubble region. This usually occurs because the heaters and diagnostics used to measure heat transfer data are often on the order of, or larger than, the bubble characteristic length or region of influence. This has contributed to the development of many different and sometimes contradictory models of pool boiling phenomena and dominant heat transfer mechanisms. Recent investigations by Yaddanapyddi and Kim and Demiray and Kim have obtained time and space resolved heat transfer information at the bubble/heater interface under constant temperature conditions using a novel micro-heater array (10x10 array, each heater 100 microns on a side) that is semi-transparent and doubles as a measurement sensor. By using active feedback to maintain a state of constant temperature at the heater surface, they showed that the area of influence of bubbles generated in FC-72 was much smaller than predicted by standard models and that micro-conduction/micro-convection due to re-wetting dominated heat transfer effects. This study seeks to expand on the previous work by making time and space resolved measurements under bubbles nucleating on a micro-heater array operated under constant heat flux conditions. In the planned investigation, wall temperature measurements made under a single bubble nucleation site will be synchronized with high-speed video to allow analysis of the bubble energy removal from the wall.

  10. Geothermal heating retrofit at the Utah State Prison Minimum Security Facility. Final report, March 1979-January 1986

    SciTech Connect

    Not Available

    1986-01-01

    This report is a summary of progress and results of the Utah State Prison Geothermal Space Heating Project. Initiated in 1978 by the Utah State Energy Office and developed with assistance from DOE's Division of Geothermal and Hydropower Technologies PON program, final construction was completed in 1984. The completed system provides space and water heating for the State Prison's Minimum Security Facility. It consists of an artesian flowing geothermal well, plate heat exchangers, and underground distribution pipeline that connects to the existing hydronic heating system in the State Prison's Minimum Security Facility. Geothermal water disposal consists of a gravity drain line carrying spent geothermal water to a cooling pond which discharges into the Jordan River, approximately one mile from the well site. The system has been in operation for two years with mixed results. Continuing operation and maintenance problems have reduced the expected seasonal operation from 9 months per year to 3 months. Problems with the Minimum Security heating system have reduced the expected energy contribution by approximately 60%. To date the system has saved the prison approximately $18,060. The total expenditure including resource assessment and development, design, construction, performance verification, and reporting is approximately $827,558.

  11. Heat flux variations over sea ice observed at the coastal area of the Sejong Station, Antarctica

    NASA Astrophysics Data System (ADS)

    Park, Sang-Jong; Choi, Tae-Jin; Kim, Seong-Joong

    2013-08-01

    This study presents variations of sensible heat flux and latent heat flux over sea ice observed in 2011 from the 10-m flux tower located at the coast of the Sejong Station on King George Island, Antarctica. A period from July to September was selected as a sea ice period based on daily record of sea state and hourly photos looking at the Marian Cove in front of the Sejong Station. For the sea ice period, mean sensible heat flux is about -11 Wm-2, latent heat flux is about +2 W m-2, net radiation is -12 W m-2, and residual energy is -3 W m-2 with clear diurnal variations. Estimated mean values of surface exchange coefficients for momentum, heat and moisture are 5.15 × 10-3, 1.19 × 10-3, and 1.87 × 10-3, respectively. The observed exchange coefficients of heat shows clear diurnal variations while those of momentum and moisture do not show diurnal variation. The parameterized exchange coefficients of heat and moisture produces heat fluxes which compare well with the observed diurnal variations of heat fluxes.

  12. Thin film heat flux sensor for Space Shuttle Main Engine turbine environment

    NASA Technical Reports Server (NTRS)

    Will, Herbert

    1991-01-01

    The Space Shuttle Main Engine (SSME) turbine environment stresses engine components to their design limits and beyond. The extremely high temperatures and rapid temperature cycling can easily cause parts to fail if they are not properly designed. Thin film heat flux sensors can provide heat loading information with almost no disturbance of gas flows or of the blade. These sensors can provide steady state and transient heat flux information. A thin film heat flux sensor is described which makes it easier to measure small temperature differences across very thin insulating layers.

  13. Experimental Measurements of Temperature and Heat Flux in a High Temperature Black Body Cavity

    NASA Technical Reports Server (NTRS)

    Abdelmessih, Amanie N.

    1998-01-01

    During hypersonic flight, high temperatures and high heat fluxes are generated. The Flight Loads Laboratory (FLL) at Dryden Flight Research Center (DFRC) is equipped to calibrate high heat fluxes up to 1100 kW/sq m. There are numerous uncertainties associated with these heat flux calibrations, as the process is transient, there are expected to be interactions between transient conduction, natural and forced convection, radiation, and possibly an insignificant degree of oxidation of the graphite cavity. Better understanding, of these mechanisms during the calibration process, will provide more reliable heat transfer data during either ground testing or flight testing of hypersonic vehicles.

  14. Inverse estimation of near-field temperature and surface heat flux via single point temperature measurement

    NASA Astrophysics Data System (ADS)

    Wu, Chen-Wu; Shu, Yong-Hua; Xie, Ji-Jia; Jiang, Jian-Zheng; Fan, Jing

    2016-05-01

    A concept was developed to inversely estimate the near-field temperature as well as the surface heat flux for the transient heat conduction problem with boundary condition of the unknown heat flux. The mathematical formula was derived for the inverse estimation of the near-field temperature and surface heat flux via a single point temperature measurement. The experiments were carried out in a vacuum chamber and the theoretically predicted temperatures were justified in specific positions. The inverse estimation principle was validated and the estimation deviation was evaluated for the present configuration.

  15. Ultrasonic test application in geothermal heat exchangers and civil works to monitor the grout integrity (TUC)

    NASA Astrophysics Data System (ADS)

    Mandrone, Giuseppe; Comina, Cesare; Giuliani, Andrea

    2013-04-01

    The working of a vertical geothermal probe, realized with a pipe U-tubes of high-density-polyethylene (HDPE) inserted in a grouted boreholes, is linked to the possibility to exchange heat with the surrounding soil. The concrete material useful for the borehole heat exchangers allows to satisfy a double purpose: sealing the polyethylene pipes from groundwater in the event of loss and increasing the thermal properties of the whole probe to provide a greater interaction with the underground. If this operation is not performed properly, the complete system may not satisfy the required heat demand, even with a well dimensioned installation, wasting the value of the entire carried out work. This paper offers to a wide group of professional actors a possible ultrasonic method of a draft and economically sustainable investigation for the identification of defects that could be present in the cementation realized inside a geothermal probe, but also in the realization of sonic piles. The instrument used for this type of test (TUC - Test Ultrasonic Cementation) has been designed and tested by the technicians of AG3, a Spin Off Company of Torino University, in collaboration with 3DM Electric and PASI companies, then subjected to patenting procedure (Patent Pending TO2011A000036). The main innovative feature of this approach has been the miniaturization of the equipment, able to investigate the geothermal probes with U-tubes with standard dimension (the maximum overall dimensions of the instruments detectors is 26 mm), maintaining a sampling rate appropriate to investigate the cementation and the early centimetres of the surrounding soil. The processing of the recorded data was performed by a dedicated Matlab software. In the first part of the article is presented the calibration process, that it was carried out through ad hoc creation of two situations likely to be investigated, while in the second part the paper reports the results obtained by the application of the TUC

  16. Formation of extreme surface turbulent heat fluxes from the ocean to the atmosphere in the North Atlantic

    NASA Astrophysics Data System (ADS)

    Tilinina, N. D.; Gulev, S. K.; Gavrikov, A. V.

    2016-01-01

    The role of extreme surface turbulent fluxes in total oceanic heat loss in the North Atlantic is studied. The atmospheric circulation patterns enhancing ocean-atmosphere heat flux in regions with significant contributions of the extreme heat fluxes (up to 60% of the net heat loss) are analyzed. It is shown that extreme heat fluxes in the Gulf Stream and the Greenland and Labrador Seas occur in zones with maximal air pressure gradients, i.e., in cyclone-anticyclone interaction zones.

  17. Evaporation on/in Capillary Structures of High Heat Flux Two-Phase Devices

    NASA Technical Reports Server (NTRS)

    Faghri, Amir; Khrustalev, Dmitry

    1996-01-01

    Two-phase devices (heat pipes, capillary pumped loops, loop heat pipes, and evaporators) have become recognized as key elements in thermal control systems of space platforms. Capillary and porous structures are necessary and widely used in these devices, especially in high heat flux and zero-g applications, to provide fluid transport and enhanced heat transfer during vaporization and condensation. However, some unexpected critical phenomena, such as dryout in long heat pipe evaporators and high thermal resistance of loop heat pipe evaporators with high heat fluxes, are possible and have been encountered in the use of two-phase devices in the low gravity environment. Therefore, a detailed fundamental investigation is proposed to better understand the fluid behavior in capillary-porous structures during vaporization at high heat fluxes. The present paper addresses some theoretical aspects of this investigation.

  18. A Thermo-Hydro-Mechanical modeling of fracture opening and closing due heat extraction from geothermal reservoir

    NASA Astrophysics Data System (ADS)

    Nand Pandey, Sachchida; Chaudhuri, Abhijit; Kelkar, Sharad

    2015-04-01

    Increasing the carbon dioxide concentration in atmosphere become challenging task for the scientific community. To achieve the sustainable growth with minimum pollution in atmosphere requires the development of low carbon technology or switch towards renewable energy. Geothermal energy is one of the promising source of clean energy. Geothermal energy is also considered a sustainable, reliable and least-expensive. This study presents a numerical modeling of subsurface heat extraction from the reservoir. The combine flow, heat transfer and geo-mechanical problem are modeled using FEHM code, which was validated against existing field data, numerical code and commercial software. In FEHM the flow and heat transfer in reservoir are solved by control volume method while for mechanical deformation finite element technique is used. The 3-D computational domain (230m × 200m × 1000m) has single horizontal fault/fracture, which is located at 800 m depth from the ground surface. The fracture connects the injection and production wells. The distance between the wells is 100 m. A geothermal gradient 0.08 °C/m is considered. The temperatures at top and bottom boundaries are held fixed as 20 and 100 °C respectively. The zero heat and mass flux boundary conditions are imposed to all vertical side boundaries of the domain. The simulation results for 100 days suggests that the computational domain is sufficiently large as the temperature along the vertical boundaries are not affected by cold-water injection. To model the thermo-poro-elastic deformation, zero all three components of displacement are specified as zero at the bottom. The zero stress condition along all other boundaries allows the boundaries to move freely. The temperature and pressure dependent fluid properties such as density and viscosity with single phase flow in saturated medium is considered. We performed a series of thermo-hydro-mechanical (THM) simulations to show aperture alteration due to cold

  19. Interfacial wicking dynamics and its impact on critical heat flux of boiling heat transfer

    NASA Astrophysics Data System (ADS)

    Kim, Beom Seok; Lee, Hwanseong; Shin, Sangwoo; Choi, Geehong; Cho, Hyung Hee

    2014-11-01

    Morphologically driven dynamic wickability is essential for determining the hydrodynamic status of solid-liquid interface. We demonstrate that the dynamic wicking can play an integral role in supplying and propagating liquid through the interface, and govern the critical heat flux (CHF) against surface dry-out during boiling heat transfer. For the quantitative control of wicking, we manipulate the characteristic lengths of hexagonally arranged nanopillars within sub-micron range through nanosphere lithography combined with top-down metal-assisted chemical etching. Strong hemi-wicking over the manipulated interface (i.e., wicking coefficients) of 1.28 mm/s0.5 leads to 164% improvement of CHF compared to no wicking. As a theoretical guideline, our wickability-CHF model can make a perfect agreement with improved CHF, which cannot be predicted by the classic models pertaining to just wettability and roughness effects, independently.

  20. The evolution of atmospheric surface layer heat and momentum flux co-spectra with increasing flux Richardson number

    NASA Astrophysics Data System (ADS)

    Li, D.; Katul, G. G.; Bou-Zeid, E.

    2014-12-01

    Co-spectral budgets of turbulent sensible heat and momentum fluxes were recently combined to develop models that explain the variation of the turbulent Prandtl number with several forms of the Richardson number in stable atmospheric surface layers. The shapes of the vertical velocity and air temperature spectra, as well as a wave-number dependent relaxation time scale assumed to be the same for momentum and heat, are required in such budgets. Guided by these theoretical approaches, the shapes of the vertical velocity and temperature spectra are first examined with increasing flux Richardson number (Ri) using data from two field experiments. The focus is on the relation between spectral and co-spectral behavior in the vicinity of the so-called critical flux Richardson number (Ricr ≈ 0.2-0.25). In addition, the wave-number dependent relaxation time scales for momentum and heat fluxes are inferred and examined. Using the data and extensions to the co-spectral budgets, results pertaining to how the shapes of the vertical velocity and temperature spectra impact the relative importance of turbulent kinetic energy (in the vertical direction) and potential energy, as well as the origin of any dissimilarity between relaxation time scales for momentum and heat fluxes are presented. The findings here offer a new perspective on how to bridge the micro-states of the energy distribution of eddies (kinetic and potential) with macroscopic relations needed in practical problems such as determination of stability correction functions to the mean flow.

  1. Enhancing Condensers for Geothermal Systems: the Effect of High Contact Angles on Dropwise Condensation Heat Transfer

    SciTech Connect

    Kennedy, John M.; Kim, Sunwoo; Kim, Kwang J.

    2009-10-06

    Phase change heat transfer is notorious for increasing the irreversibility of, and therefore decreasing the efficiency of, geothermal power plants. Its significant contribution to the overall irreversibility of the plant makes it the most important source of inefficiency in the process. Recent studies here have shown the promotion of drop wise condensation in the lab by means of increasing the surface energy density of a tube with nanotechnology. The use of nanotechnology has allowed the creation of surface treatments which discourage water from wetting a tube surface during a static test. These surface treatments are unique in that they create high- contact angles on the condensing tube surfaces to promote drop wise condensation.

  2. Elimination of Heat-Shielding for Geothermal Tools Operating Up To 300 Degress Celsius

    SciTech Connect

    HENFLING,JOSEPH A.; NORMANN,RANDY A.

    1999-10-07

    This report focuses Sandia National Laboratories' effort to create high-temperature logging tools for geothermal applications not requiring heat-shielding. Tool electronics can operate up to 300 C with a few limiting components operating to 250 C. Second generation electronics are needed to increase measurement accuracy and extend the operating range to 300 and then 350 C are identified. Custom development of high-temperature batteries and assembling techniques are touched on. Outcomes of this work are discussed and new directions for developing high-temperature industry are suggested.

  3. Institutional and financial guide to geothermal district heating, serial no. 2

    NASA Astrophysics Data System (ADS)

    1982-03-01

    General planning considerations which affect nearly every community are reviewed, and alternative operating structures which are available to communities are reviewed, including local governments, nonprofit cooperatives, private enterprises, and joint ventures. The financing options available to publicly-owned and privately-owned district heating systems are then summarized. The geothermal production and distribution activities most appropriate to each type of operating structure are reviewed, along with typical equity and debt funding sources. The tax advantages for private developers are described, as are the issues of customer contracts and service prices, and customer retrofit financing. The treatment is limited to an introductory overview.

  4. Thin film heat flux sensors fabricated on copper substrates for thermal measurements in microfluidic environments

    NASA Astrophysics Data System (ADS)

    Jasperson, Benjamin A.; Schmale, Joshua; Qu, Weilin; Pfefferkorn, Frank E.; Turner, Kevin T.

    2014-12-01

    Micro-scale heat flux sensors are fabricated on bulk copper surfaces using a combination of lithography-based microfabrication and micro end milling. The heat flux sensors are designed to enable heat transfer measurements on an individual pin in a copper micro pin fin heat sink. Direct fabrication of the sensors on copper substrates minimizes the thermal resistance between the sensor and pin. To fabricate the devices, copper wafers were polished to a flatness and roughness suitable for microfabrication and standard processes, including photolithography, polyimide deposition via spinning, and metal deposition through physical vapor deposition were tailored for use on the unique copper substrates. Micro end milling was then used to create 3D pin features and segment the devices from the copper substrate. Temperature calibrations of the sensors were performed using a tube furnace and the heat flux sensing performance was assessed through laser-based tests. This paper describes the design, fabrication and calibration of these integrated heat flux sensors.

  5. Progress in the measurement of SSME turbine heat flux with plug-type sensors

    NASA Technical Reports Server (NTRS)

    Liebert, Curt H.

    1991-01-01

    Data reduction was completed for tests of plug-type heat flux sensors (gauges) in a turbine blade thermal cycling tester (TBT) that is located at NASA/Marshall Space Flight Center, and a typical gauge is illustrated. This is the first time that heat flux has been measured in a Space Shuttle Main Engine (SSME) Turbopump Turbine environment. The development of the concept for the gauge was performed in a heat flux measurement facility at Lewis. In this facility, transient and steady state absorbed surface heat flux information was obtained from transient temperature measurements taken at points within the gauge. A schematic of the TBT is presented, and plots of the absorbed surface heat flux measured on the three blades tested in the TBT are presented. High quality heat flux values were measured on all three blades. The experiments demonstrated that reliable and durable gauges can be repeatedly fabricated into the airfoils. The experiment heat flux data are being used for verification of SSME analytical stress, boundary layer, and heat transfer design models. Other experimental results and future plans are also presented.

  6. Measurements of the instantaneous local heat flux in turbulent Rayleigh-Bénard convection

    NASA Astrophysics Data System (ADS)

    du Puits, Ronald; Resagk, Christian; Thess, André

    2010-07-01

    We present measurements of the instantaneous local heat flux in highly turbulent Rayleigh-Bénard (RB) convection in air (Pr=0.7) for aspect ratios in the range 1.13<=Γ<=9.00 and for Rayleigh numbers in the range 1.3×109<=Ra<=9.6×1011. The measurements have been carried out simultaneously at the surfaces of the heating and the cooling plate using a commercial sensor whose diameter is 360 times smaller than the diameter of the RB facility. We find that for all investigated values of Ra and Γ the time-averaged local heat flux at the centres of the heating and cooling plates is significantly higher than the global heat flux obtained in previous measurements. In particular, for the smallest investigated aspect ratio, Γ=1.13, the scaling exponents of the local heat fluxes as functions of the Rayleigh number are found to be considerably below those of the global heat flux obtained in experiments with cryogenic helium at Γ=1 by Niemela and Sreenivasan (2003 J. Fluid Mech. 481 355-84). Our measurements indicate that the spatial distribution of the heat flux at the heating and cooling plates is strongly nonuniform and that this nonuniformity decreases with increasing Ra and Γ. Our investigations of the time dependence of the local heat fluxes show that these quantities undergo fluctuations up to ±15% of their time-averaged values. Our work suggests that local heat flux measurements at different positions along heating and cooling plates are useful for a deeper understanding of the scaling properties of the (global) Nusselt number in RB convection.

  7. Scale Resistant Heat Exchanger for Low Temperature Geothermal Binary Cycle Power Plant

    SciTech Connect

    Hays, Lance G.

    2014-11-18

    Phase 1 of the investigation of improvements to low temperature geothermal power systems was completed. The improvements considered were reduction of scaling in heat exchangers and a hermetic turbine generator (eliminating seals, seal system, gearbox, and lube oil system). A scaling test system with several experiments was designed and operated at Coso geothermal resource with brine having a high scaling potential. Several methods were investigated at the brine temperature of 235 ºF. One method, circulation of abradable balls through the brine passages, was found to substantially reduce scale deposits. The test heat exchanger was operated with brine outlet temperatures as low as 125 ºF, which enables increased heat input available to power conversion systems. For advanced low temperature cycles, such as the Variable Phase Cycle (VPC) or Kalina Cycle, the lower brine temperature will result in a 20-30% increase in power production from low temperature resources. A preliminary design of an abradable ball system (ABS) was done for the heat exchanger of the 1 megawatt VPC system at Coso resource. The ABS will be installed and demonstrated in Phase 2 of this project, increasing the power production above that possible with the present 175 ºF brine outlet limit. A hermetic turbine generator (TGH) was designed and manufacturing drawings produced. This unit will use the working fluid (R134a) to lubricate the bearings and cool the generator. The 200 kW turbine directly drives the generator, eliminating a gearbox and lube oil system. Elimination of external seals eliminates the potential of leakage of the refrigerant or hydrocarbon working fluids, resulting in environmental improvement. A similar design has been demonstrated by Energent in an ORC waste heat recovery system. The existing VPC power plant at Coso was modified to enable the “piggyback” demonstration of the TGH. The existing heat exchanger, pumps, and condenser will be operated to provide the required

  8. Liquid jet impingement cooling with diamond substrates for extremely high heat flux applications

    SciTech Connect

    Lienhard, J.H. V; Khounsary, A.M.

    1993-09-01

    The combination of impinging jets and diamond substrates may provide an effective solution to a class of extremely high heat flux problems in which very localized heat loads must be removed. Some potential applications include the cooling of high-heat-load components in synchrotron x-ray, fusion, and semiconductor laser systems. Impinging liquid jets are a very effective vehicle for removing high heat fluxes. The liquid supply arrangement is relatively simple, and low thermal resistances can be routinely achieved. A jet`s cooling ability is a strong function of the size of the cooled area relative to the jet diameter. For relatively large area targets, the critical heat fluxes can approach 20 W/mm{sup 2}. In this situation, burnout usually originates at the outer edge of the cooled region as increasing heat flux inhibits the liquid supply. Limitations from liquid supply are minimized when heating is restricted to the jet stagnation zone. The high stagnation pressure and high velocity gradients appear to suppress critical flux phenomena, and fluxes of up to 400 W/mm{sup 2} have been reached without evidence of burnout. Instead, the restrictions on heat flux are closely related to properties of the cooled target. Target properties become an issue owing to the large temperatures and large temperature gradients that accompany heat fluxes over 100 W/mm{sup 2}. These conditions necessitate a target with both high thermal conductivity to prevent excessive temperatures and good mechanical properties to prevent mechanical failures. Recent developments in synthetic diamond technology present a possible solution to some of the solid-side constraints on heat flux. Polycrystalline diamond foils can now be produced by chemical vapor deposition in reasonable quantity and at reasonable cost. Synthetic single crystal diamonds as large as 1 cm{sup 2} are also available.

  9. Heat Fluxes and Evaporation Measurements by Multi-Function Heat Pulse Probe: a Laboratory Experiment

    NASA Astrophysics Data System (ADS)

    Sharma, V.; Ciocca, F.; Hopmans, J. W.; Kamai, T.; Lunati, I.; Parlange, M. B.

    2012-04-01

    Multi Functional Heat Pulse Probes (MFHPP) are multi-needles probes developed in the last years able to measure temperature, thermal properties such as thermal diffusivity and volumetric heat capacity, from which soil moisture is directly retrieved, and electric conductivity (through a Wenner array). They allow the simultaneous measurement of coupled heat, water and solute transport in porous media, then. The use of only one instrument to estimate different quantities in the same volume and almost at the same time significantly reduces the need to interpolate different measurement types in space and time, increasing the ability to study the interdependencies characterizing the coupled transports, especially of water and heat, and water and solute. A three steps laboratory experiment is realized at EPFL to investigate the effectiveness and reliability of the MFHPP responses in a loamy soil from Conthey, Switzerland. In the first step specific calibration curves of volumetric heat capacity and thermal conductivity as function of known volumetric water content are obtained placing the MFHPP in small samplers filled with the soil homogeneously packed at different saturation degrees. The results are compared with literature values. In the second stage the ability of the MFHPP to measure heat fluxes is tested within a homemade thermally insulated calibration box and results are matched with those by two self-calibrating Heatflux plates (from Huxseflux), placed in the same box. In the last step the MFHPP are used to estimate the cumulative subsurface evaporation inside a small column (30 centimeters height per 8 centimeters inner diameter), placed on a scale, filled with the same loamy soil (homogeneously packed and then saturated) and equipped with a vertical array of four MFHPP inserted close to the surface. The subsurface evaporation is calculated from the difference between the net sensible heat and the net heat storage in the volume scanned by the probes, and the

  10. Method of high heat flux removal by usage of liquid spray cooling

    NASA Astrophysics Data System (ADS)

    Smakulski, Przemysław

    2013-09-01

    High heat flux removal are important issue in many perspective applications such as computer chips, laser diode arrays, or boilers working on supercritical parameters. Electronic microchips constructed nowadays are model example of high heat flux removal, where the cooling system have to maintain the temperature below 358 K and take heat flux up to 300 W/cm2. One of the most efficient methods of microchips cooling turns out to be the spray cooling method. Review of installations has been accomplished for removal at high heat flux with liquid sprays. In the article are shown high flux removal characteristic and dependences, boiling critical parameters, as also the numerical method of spray cooling analysis.

  11. Infrared radiometric technique for rapid quantitative evaluation of heat flux distribution over large areas

    NASA Astrophysics Data System (ADS)

    Glazer, Stuart; Siebes, Georg

    1989-03-01

    This paper describes a novel approach for rapid, quantitative measurement of spatially distributed heat flux incident on a plane. The technique utilizes the spatial temperature distribution on an opaque thin film at the location of interest, as measured by an imaging infrared radiometer. Knowledge of film radiative properties, plus quantitative estimates of convection cooling permit the steady state energy balance at any location on the film sheet to be solved for the incident heat flux. Absolute accuracies on the order of 10-15 percent have been obtained in tests performed in air. The method is particularly useful for evaluation of spatial heat flux uniformity from distributed heat sources over large areas. It has recently been used in several applications at the Jet Propulsion Laboratory, including flux uniformity measurements from large distributed quartz lamp arrays used during thermal vacuum testing of several spacecraft components, and flux mapping of a low power NdYg laser beam.

  12. The effect of ocean heat flux on seasonal ice growth in Young Sound (Northeast Greenland)

    NASA Astrophysics Data System (ADS)

    Kirillov, Sergei; Dmitrenko, Igor; Babb, David; Rysgaard, Søren; Barber, David

    2015-07-01

    The seasonal ice cover plays an important role in the climate system limiting the exchange of heat and momentum across the air-water interface. Among other factors, sea ice is sensitive to the ocean heat flux. In this study, we use in situ oceanographic, sea ice, and meteorological data collected during winter 2013/2014 in Young Sound (YS) fjord in Northeast Greenland to estimate the ocean heat flux to the landfast ice cover. During the preceding ice-free summer, incident solar radiation caused sea surface temperatures of up to 5-6°C. Subsequently, this heat was transferred down to the intermediate depths, but returned to the surface and retarded ice growth throughout winter. Two different approaches were used to estimate the ocean heat fluxes; (i) a residual method based on a 1-D thermodynamic ice growth model and (ii) a bulk parameterization using friction velocities and available heat content of water beneath the ice. The average heat flux in the inner YS varied from 13 W m-2 in October-December to less than 2 W m-2 in January-May. An average heat flux of 9 W m-2 was calculated for the outer YS. Moreover, we show that the upward heat flux in the outer fjord is strongly modulated by surface outflow, which produced two maxima in heat flux (up to 18-24 W m-2) during 26 December to 27 January and from 11 February to 14 March. By May 2014, the upward ocean heat flux reduced the landfast ice thickness by 18% and 24% in the inner and outer YS, respectively.

  13. Elastic thickness and heat flux estimates for the uranian satellite Ariel

    NASA Astrophysics Data System (ADS)

    Peterson, G.; Nimmo, F.; Schenk, P.

    2015-04-01

    The surface of Ariel, an icy satellite orbiting Uranus, shows extensional tectonic features suggesting an episode of endogenic heating in the satellite's past. Using topography derived from stereo-photoclinometry, we identified flexural uplift at a rift zone suggesting elastic thickness values in the range 3.8-4.4 km. We estimate the temperature at the base of the lithosphere to be in the range 99-146 K, depending on the strain rate assumed, with corresponding heat fluxes of 28-92 mW/m2. Neither tidal heating, assuming Ariel's current eccentricity, nor radiogenic heat production from the silicate core are enough to cause the inferred heat fluxes. None of three proposed ancient mean-motion resonances produce equilibrium tidal heating values in excess of 4.3 mW/m2. Thus, the origin of the inferred high heat fluxes is currently mysterious.

  14. Enhancement of critical heat flux in tubes using staged tangential flow injection: (Progress report)

    SciTech Connect

    Dhir, V.K.

    1987-01-01

    Experimental studies of the enhancement in single and two phase heat transfer from tubes subjected to tangential flow injection have been continuing. Investigations using water as the test liquid have been focused on: single phase heat transfer coefficients; two phase heat transfer coefficients under subcooled boiling conditions; subcooled critical heat fluxes; and modeling of the enhancement under swirl flow conditions. With tangential injection up to four fold increase in the average heat transfer coefficient has been observed. During subcooled boiling the enhancement is relatively small. However swirl induced centripetal force increases vapor escape velocity and as a result higher critical heat fluxes can be accommodated. In the range of flow parameters studied up to 40% enhancement in critical heat flux has been observed with single stage injection. This enhancement is slightly less than that obtained with Freon-113. The mechanistic reasons for this observation are currently being investigated.

  15. Estimation of Surface Heat Flux and Surface Temperature during Inverse Heat Conduction under Varying Spray Parameters and Sample Initial Temperature

    PubMed Central

    Aamir, Muhammad; Liao, Qiang; Zhu, Xun; Aqeel-ur-Rehman; Wang, Hong

    2014-01-01

    An experimental study was carried out to investigate the effects of inlet pressure, sample thickness, initial sample temperature, and temperature sensor location on the surface heat flux, surface temperature, and surface ultrafast cooling rate using stainless steel samples of diameter 27 mm and thickness (mm) 8.5, 13, 17.5, and 22, respectively. Inlet pressure was varied from 0.2 MPa to 1.8 MPa, while sample initial temperature varied from 600°C to 900°C. Beck's sequential function specification method was utilized to estimate surface heat flux and surface temperature. Inlet pressure has a positive effect on surface heat flux (SHF) within a critical value of pressure. Thickness of the sample affects the maximum achieved SHF negatively. Surface heat flux as high as 0.4024 MW/m2 was estimated for a thickness of 8.5 mm. Insulation effects of vapor film become apparent in the sample initial temperature range of 900°C causing reduction in surface heat flux and cooling rate of the sample. A sensor location near to quenched surface is found to be a better choice to visualize the effects of spray parameters on surface heat flux and surface temperature. Cooling rate showed a profound increase for an inlet pressure of 0.8 MPa. PMID:24977219

  16. Recovery act. Development of design and simulation tool for hybrid geothermal heat pump system

    SciTech Connect

    Wang, Shaojie; Ellis, Dan

    2014-05-29

    The ground source heat pump (GSHP) system is one of the most energy efficient HVAC technologies in the current market. However, the heat imbalance may degrade the ability of the ground loop heat exchanger (GLHX) to absorb or reject heat. The hybrid GSHP system, which combines a geothermal well field with a supplemental boiler or cooling tower, can balance the loads imposed on the ground loop heat exchangers to minimize its size while retaining superior energy efficiency. This paper presents a recent simulation-based study with an intention to compare multiple common control strategies used in hybrid GSHP systems, including fixed setpoint, outside air reset, load reset, and wetbulb reset. A small office in Oklahoma City conditioned by a hybrid GSHP system was simulated with the latest version of eQUEST 3.7[1]. The simulation results reveal that the hybrid GSHP system has the excellent capability to meet the cooling and heating setpoints during the occupied hours, balance thermal loads on the ground loop, as well as improve the thermal comfort of the occupants with the undersized well field.

  17. Thermal conductivity of cementitious grouts for geothermal heat pumps. Progress report FY 1997

    SciTech Connect

    Allan, M.L.

    1997-11-01

    Grout is used to seal the annulus between the borehole and heat exchanger loops in vertical geothermal (ground coupled, ground source, GeoExchange) heat pump systems. The grout provides a heat transfer medium between the heat exchanger and surrounding formation, controls groundwater movement and prevents contamination of water supply. Enhanced heat pump coefficient of performance (COP) and reduced up-front loop installation costs can be achieved through optimization of the grout thermal conductivity. The objective of the work reported was to characterize thermal conductivity and other pertinent properties of conventional and filled cementitious grouts. Cost analysis and calculations of the reduction in heat exchanger length that could be achieved with such grouts were performed by the University of Alabama. Two strategies to enhance the thermal conductivity of cementitious grouts were used simultaneously. The first of these was to incorporate high thermal conductivity filler in the grout formulations. Based on previous tests (Allan and Kavanaugh, in preparation), silica sand was selected as a suitable filler. The second strategy was to reduce the water content of the grout mix. By lowering the water/cement ratio, the porosity of the hardened grout is decreased. This results in higher thermal conductivity. Lowering the water/cement ratio also improves such properties as permeability, strength, and durability. The addition of a liquid superplasticizer (high range water reducer) to the grout mixes enabled reduction of water/cement ratio while retaining pumpability. Superplasticizers are commonly used in the concrete and grouting industry to improve rheological properties.

  18. Estimation of surface heat flux and temperature distributions in a multilayer tissue based on the hyperbolic model of heat conduction.

    PubMed

    Lee, Haw-Long; Chen, Wen-Lih; Chang, Win-Jin; Yang, Yu-Ching

    2015-01-01

    In this study, an inverse algorithm based on the conjugate gradient method and the discrepancy principle is applied to solve the inverse hyperbolic heat conduction problem in estimating the unknown time-dependent surface heat flux in a skin tissue, which is stratified into epidermis, dermis, and subcutaneous layers, from the temperature measurements taken within the medium. Subsequently, the temperature distributions in the tissue can be calculated as well. The concept of finite heat propagation velocity is applied to the modeling of the bioheat transfer problem. The inverse solutions will be justified based on the numerical experiments in which two different heat flux distributions are to be determined. The temperature data obtained from the direct problem are used to simulate the temperature measurements. The influence of measurement errors on the precision of the estimated results is also investigated. Results show that an excellent estimation on the time-dependent surface heat flux can be obtained for the test cases considered in this study.

  19. Measurement of Heat Flux at Metal-Mold Interface during Casting Solidification

    SciTech Connect

    Sabau, Adrian S

    2006-01-01

    All previous studies on interfacial heat transfer coefficient have been based on indirect methods for estimating the heat flux that employed either inverse heat transfer analysis procedures or instrumentation arrangements to measure temperatures and displacements near the metal-mold interface. In this paper, the heat transfer at the metal-mold interfaces is investigated using a sensor for the direct measurement of heat flux. The heat flux sensor (HFS) was rated for 700oC and had a time response of less than 10 ms. Casting experiments were conducted using graphite molds for aluminum alloy A356. Several casting experiments were performed using a graphite coating and a boron nitride coating. The measurement errors were estimated. The temperature of the mold surface was provided by the HFS while the temperature of the casting surface was measured using a thermocouple. Results for the heat transfer coefficients were obtained based on measured heat flux and temperatures. Four stages were clearly identified for the variation in time of the heat flux. Values of the heat transfer coefficient were in good agreement with data from previous studies.

  20. Self-Regulated Plasma Heat Flux Mitigation Due to Liquid Sn Vapor Shielding

    NASA Astrophysics Data System (ADS)

    van Eden, G. G.; Morgan, T. W.; Aussems, D. U. B.; van den Berg, M. A.; Bystrov, K.; van de Sanden, M. C. M.

    2016-04-01

    A steady-state high-flux H or He plasma beam was balanced against the pressure of a Sn vapor cloud for the first time, resulting in a self-regulated heat flux intensity near the liquid surface. A temperature response of the liquid surface characterized by a decoupling from the received heating power and significant cooling of the plasma in the neutral Sn cloud were observed. The plasma heat flux impinging on the target was found to be mitigated, as heat was partially dissipated by volumetric processes in the vapor cloud rather than wholly by surface effects. These results motivate further exploration of liquid metal solutions to the critical challenge of heat and particle flux handling in fusion power plants.