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Sample records for solar desiccant cooling

  1. Solar Assisted Adsorptive Desiccant Cooling System

    NASA Astrophysics Data System (ADS)

    Ohkura, Masashi; Kodama, Akio

    Desiccant cooling processes can supply dry air by using lower temperature heat energy such as waste heat or solar heat. Especially, solar heat is useful heat source for the desiccant cooling since solar heat in summer tends to be surplus. This paper discusses the hourly cooling performance of the solar assisted desiccant cooling system, which consists of a desiccant wheel, a thermal wheel, two evaporative coolers, a cooling coil and flat plate solar water heater, assuming that the cooling system is applied to an office room of 250m3 in volume. The estimation indicated that the surface area needed to satisfy the dehumidifying performance in a sunny day was at least 30m2. Furthermore, surface area of 40m2 or larger provided a surplus dehumidifying performance causing a sensible cooling effect in evaporative cooler. Surface area of 30 m2 did not satisfy the dehumidifying performance required for high humidity condition, over 18.0g/kg(DA). The cooling demand of the cooling coil increased in such humidity condition due to the decrease in the sensible cooling effect of evaporative cooler. Auxiliary heater was required in a cloudy day since the temperature of water supplied from solar water heater of 40m2 did not reach sufficient level.

  2. Solar Assisted Adsorptive Desiccant Cooling System

    NASA Astrophysics Data System (ADS)

    Ohkura, Masashi; Kodama, Akio

    Solar assisted desiccant coo1ing process is an effective means to reduce a latent heat load of the ventilation air. This paper describes the influences of ambient humidity and sensible heat factor (SHF) of the indoor room on the performance and scale of the desiccant cooling system. Two process configurations termed “ambient air mode” and “mixed air mode” were assumed. At “ambient air mode”, only ambient air is dehumidified and cooled in the desiccant process. The dehumidified air stream is mixed with return air and further cooled in the cooling coil. At “mixed air mode”, ambient air is mixed with return air and this mixed air stream is dehumidified in the desiccant process and cooled at the cooling coil. At “ambient air mode”, ambient air humidity had a significant impact on required amount of dehumidification since humid ambient air entered the desiccant process directly. In this case, higher temperature level and quantity, which is impossible to be supplied from commonly commercialized flat panel solar collectors, was required. At “mixed air mode”, the influence of increase of ambient humidity was not significant since humidity of the air entering the desiccant process became low by mixing with return air. At this mode, it was expected that 70°C of the circulating water and 37m2 of surface area of solar collector could produce a sufficient dehumidifying performance even in high latent heat condition. The contributing ratio of the desiccant wheel was also estimated. The ratio increased in higher latent heat condition due to increase of required amount of dehumidification. The contributing ratio of the thermal wheel became lower due to increase of saturated air temperature in the evaporative cooler.

  3. Desiccant cooling using unglazed transpired solar collectors

    NASA Astrophysics Data System (ADS)

    Pesaran, A. A.; Wipke, K.

    1992-05-01

    The use of unglazed solar collectors for desiccant regeneration in a solid desiccant cooling cycle was investigated because these collectors are lower in cost than conventional glazed flat-plate collectors. Using computer models, the performance of a desiccant cooling ventilation cycle integrated with either unglazed transpired collectors or conventional glazed flat-plate collectors was obtained. We found that the thermal performance of the unglazed system was lower than the thermal performance of the glazed system because the unglazed system could not take advantage of the heat of adsorption released during the dehumidification process. For a 3-ton cooling system, although the area required for the unglazed collector was 69 percent more than that required for the glazed collector, the cost of the unglazed collector array was 44 percent less than the cost of the glazed collector array. The simple payback period of the unglazed system was half of the payback period of the glazed collector when compared to an equivalent gas-fired system. Although the use of unglazed transpired collectors makes economic sense, some practical considerations may limit their use in desiccant regeneration.

  4. Advanced solar/gas desiccant cooling system

    NASA Astrophysics Data System (ADS)

    Huskey, B.; Sharp, J.; Venero, A.; Yen, M.

    1982-02-01

    A desiccant cooling system with significantly higher thermal efficiency than current state of the art desiccant systems is studied. The findings and data are based on extensive computer modeling and actual operating test results of an experimental breadboard unit employing an approach developed for the separation of moisture from an airstream using solid desiccants (silica gel). The results confirmed the theoretical concept of efficiency improvement over desiccant concepts and validated the computer model used for sizing and simulating the desiccant process. The results also identified specific components and areas of the system needing improvements such as air seals, wheel drive mechanisms, air distribution and materials.

  5. Experimental investigation of a solar desiccant cooling installation

    SciTech Connect

    Bourdoukan, P.; Wurtz, E.; Joubert, P.

    2009-11-15

    Desiccant cooling is a technique based on evaporative cooling and air dehumidification using desiccant regenerated by thermal energy. It is particularly interesting when it is driven by waste or solar heat making this technique environmentally friendly. In this paper, an experimental investigation is carried on a desiccant air handling unit powered by vacuum-tube solar collectors. First, the components are studied under various operating conditions. Then overall performance of the installation is evaluated over a day for a moderately humid climate with regeneration solely by solar energy. In these conditions the overall efficiency of the solar installation is 0.55 while the thermodynamic coefficient of performance is 0.45 and the performance indicator based on the electrical consumption is 4.5. Finally, the impact of outside and regeneration conditions on the performance indicators is studied. (author)

  6. Analysis of advanced solar hybrid desiccant cooling systems for buildings

    SciTech Connect

    Schlepp, D.; Schultz, K.

    1984-10-01

    This report describes an assessment of the energy savings possible from developing hybrid desiccant/vapor-compression air conditioning systems. Recent advances in dehumidifier design for solar desiccant cooling systems have resulted in a dehumidifier with a low pressure drop and high efficiency in heat and mass transfer. A recent study on hybrid desiccant/vapor compression systems showed a 30%-80% savings in resource energy when compared with the best conventional systems with vapor compression. A system consisting of a dehumidifier with vapor compression subsystems in series was found to be the simplest and best overall performer.

  7. Solar space heating and cooling by selective use of the components of a desiccant cooling system

    NASA Astrophysics Data System (ADS)

    Abbud, Ihsan Aladdin

    The economic advantages of by-passing various components of a desiccant cooling system under conditions not requiring their use are estimated by evaluating the annual costs of heating and cooling a commercial building in three representative U.S. cities. Life-cycle costs of systems employing solar heat for space heating and desiccant regeneration are compared with those using electric heat. The costs of purchasing and operating heating and desiccant cooling systems, with and without solar heat supply, are compared with those employing conventional heating and vapor compression cooling. The conditions under which commercial buildings can be cooled with desiccant systems at costs competitive with conventional systems are identified. A commercially available vapor compression air conditioner is used as a standard of comparison for energy consumption and room comfort. Heating and cooling requirements of the building are determined by use of the BLAST computer model in a simulation of long term system operation. Performance of the desiccant cooling system and life cycle savings obtained by its use are determined by simulation employing the TRNSYS computer model. TRNSYS compatible subroutines are developed to simulate operation of the desiccant equipment, the building, and the controllers that operate and monitor the system components. The results are presented in tabular and graphical form. This study shows that in the widely different climates represented in Los Angeles, New York, and Miami, by-passing various components in the desiccant cooling system when they are not needed is economically advantageous. Operation cost of the complete system decreased by 47.3% in Los Angeles, by 30.9% in New York City, and by 23.9% in Miami by not operating the desiccant wheel and other elements. The ventilation desiccant cooling system has major economic advantage over conventional systems under conditions of moderate humidity, as in Los Angeles and New York City. In Miami, however

  8. Study of parameters affecting the performance of solar desiccant cooling systems

    NASA Astrophysics Data System (ADS)

    Pesaran, A. A.; Hoo, E. A.

    1993-01-01

    The performance of a solar desiccant cooling system depends on the performance of its components, particularly the desiccant dehumidifier and solar collectors. The desiccant dehumidifier performance is affected by the properties of the desiccant, particularly the shape of the isotherm and the regeneration temperature. The performance of a solar collector, as one would expect, depends on its operating temperature, which is very close to the desiccant regeneration temperature. The purpose of this study was to identify the desiccant isotherm shape (characterized by separation factor) that would result in the optimum performance - based on thermal coefficient of performance and cooling capacity - of a desiccant cooling cycle operating in ventilation mode. Different regeneration temperatures ranging from 65 to 160 C were investigated to identify the corresponding optimum isotherm shape at each. Thermal COP dictates the required area of the solar collectors, and the cooling capacity is an indication of the size and cost of the cooling equipment. Staged and no-staged regeneration methods were studied.

  9. High performance solar desiccant cooling system: Performance evaluation and research recommendations

    NASA Astrophysics Data System (ADS)

    Schlepp, D. R.; Schultz, K. J.

    1984-09-01

    The current status of solar desiccant cooling was assessed and recommendations were made for continued research to develop high performance systems competitive with conventional cooling systems. Solid desiccant, liquid desiccant, and hybrid systems combining desiccant dehumidifiers with vapor compressor units are considered. Currently, all desiccant systems fall somewhat short of being competitive with conventional systems. Hybrid systems appear to have the greatest potential in the short term. Solid systems are close to meeting performance goals. Development of high performance solid desiccant dehumidifiers based on parallel passage designs should be pursued. Liquid system collector/generators and efficient absorbers should receive attention. Model development is also indicated. Continued development by hybrid systems is directly tied to the above work.

  10. A Field-Test of Solar Assisted Adsorptive Desiccant Cooling System

    NASA Astrophysics Data System (ADS)

    Ohkura, Masashi; Kodama, Akio; Hirose, Tsutomu

    A field-test of solar assisted desiccant evaporative cooling process has been carried out, which is a quite attractive cooling / dehumidification process considering various environmental problems caused by conventional electricity driven air conditioners. The process performance has been examined by means of temperature drop between outside air and supply air and COPs (COP value based on solar irradiation). This cooling performance was strongly influenced by solar irradiation and ambient air condition. Stable irradiation produced a higher regeneration temperature resulting higher dehumidifying performance. At one day with as table solar irradiation, the cooling process could produce cool supply air of 18.7°C against the ambient air of 30.1°C and averaged COP, was 0.41. On the other hand, unstable irradiation due to some clouds made the dehumidifying performance lower. However, decrease in the cooling performance was small compared to that obtained at the stable irradiation condition. This is due to buffering by thermal storage of the water circulating in solar collectors. Influence of ambient humidity on the cooling performance was rather serious. At higher humidity condition, the amount of dehumidified water became larger due to increase of effective adsorption capacity of the desiccant rotor. However, the temperature drop was decreased to 6.9°C. This behavior was mainly due to simultaneous increase of humidity and temperature in the dehumidified air. In this situation, an effective evaporation in the following water spray evaporative cooler did not occur.

  11. A low-cost-solar liquid desiccant system for residential cooling

    NASA Astrophysics Data System (ADS)

    Ware, Joel D., III

    The use of liquid desiccants for dehumidification of heating, ventilation, and air conditioning (HVAC) process air is becoming a more promising concept as the drive for energy conservation continues to grow. Recently, liquid desiccant systems have been implemented on the commercial level in conjunction with evaporative coolers and have recorded energy savings upwards of 50%. The aim of this research is to test the potential liquid desiccant systems have on the residential level when paired with a conventional vapor compression cycle and to construct a system that would overcome some of its barriers to the residential market. A complete low-cost-solar liquid desiccant system was designed, constructed, and tested in the Off-Grid Zero Emissions Building (OGZEB) at the Florida State University. Key design characteristics include turbulent process air flow through the conditioner and airside heating in the regenerator. The system was tested in the two following ways: (1) for the energy savings while maintaining a constant temperature over a twenty four hour period and (2) for the energy savings over a single cooling cycle. The liquid desiccant system achieved a maximum energy savings of 38% over a complete day and 52% over a single cooling cycle. It was projected that the system has the potential to save 1064 kWh over the course of a year. When combined with a renewable source of heat for regeneration, liquid desiccant systems become very cost effective. The levelized cost of energy for the combination of the liquid desiccant system and solar thermal collectors was calculated to be 7.06 C/kWh with a payback period of 4.4 years. This research provides evidence of the technology's potential on the residential sector and suggests ways for it to become competitive in the market.

  12. Experiments on sorption characteristics of solid desiccant materials for solar desiccant cooling systems

    SciTech Connect

    Pesaran, A.A.

    1984-11-01

    A test facility for measuring the sorption properties of candidate solid desiccant materials under dynamic conditions as well as equilibrium conditions, those experienced during desiccant dehumidifier operation, was constructed and tested. The theory of perturbation chromatography was initially used to measure the equilibrium properties of a desiccant/water-vapor system for the first time. Silica gel, molecular sieve, and gamma-manganese dioxide were tested. The equilibrium capacity estimated by the perturbation chromatography was lower than those available in literature, which suggests that perturbation chromatography may not be applicable to desiccant/water-vapor systems. The perturbation chromatography was replaced with a gravimetric technique, and satisfactory results were obtained for a water-vapor/molecular-sieve system.

  13. Solar-regenerated desiccant dehumidification

    NASA Astrophysics Data System (ADS)

    Haves, P.

    1982-02-01

    The dehumidification requirements of buildings are discussed, and the most suitable desiccant material is identified as silica gel. Several conceptual designs for solar regenerated desiccant dehumidifiers using a solid desiccant are described. The construction and operation of a laboratory experiment to determine the performance of a packed bed of silica gel at low flow rate is described. The experimental results are presented and compared to the predictions of a simple computer model which assumes local equilibrium between the desiccant and the airstream. The simulations used to predict desiccant bed performance and the integration of the desiccant bed simulation with a simulation of the thermal performance of a passively cooled residence are described. Results for an average July day are presented. Sizing relationships derived from the simulation are described, and an economic analysis and recommendations for further work are presented.

  14. Optimizing the performance of desiccant beds for solar-regenerated cooling

    NASA Astrophysics Data System (ADS)

    Barlow, R.; Collier, K.

    1981-03-01

    The use of computer simulations as well as a simplified psychrometric analysis to determine the increase in cooling system performance that can be realized through the use of nonhomogeneous or staged desiccant beds was investigated. A staged bed of four hypothetical desiccants gives, a 10% higher cooling capacity than a silica gel bed of the same thickness. Alternatively, the same cooling capacity is produced by a staged bed 37% thinner than the silica gel bed. It is suggested that these effects can be employed to reduce the parasitic power requirements of deciccant cooling systems.

  15. Closed cycle desiccant cooling system

    NASA Astrophysics Data System (ADS)

    Tchernev, D. I.; Emerson, D. T.

    1986-10-01

    The breadboard prototype of a closed cycle desiccant cooling system was designed, constructed and its performance tested. The system combines the sorption properties of solid zeolite/refrigerant vapor pairs with the principle of regenerative heat exchangers. Since solid zeolites are difficult to move in vacuum tight containers and in order to avoid intermittent operation, the desiccant is housed in two separate containers which are alternately heated and cooled by a heat transfer fluid. Using the principle of energy regeneration, the heat removed from the container being cooled is recycled in the container being heated. The breadboard system, with 90 pounds of zeolite, demonstrated a recycling efficiency of 75%, while the system capacity was 2,000 Btu/hr. This significantly increased the system thermal Coefficient of Performance (COP) to 1.1 at ARI conditions from the single container thermal COP of 0.4.

  16. The performance of a solar-regenerated open-cycle desiccant bed grain cooling system

    SciTech Connect

    Ismail, M.Z.; Angus, D.E. ); Thorpe, G.R. )

    1991-01-01

    The cooling of stored food grains suppresses the growth of populations of insect pests, inhibits spoilage by fungi and helps to preserve grain quality. In temperate and subtropical climates, grains may be effectively cooled by ventilating them with ambient air. In tropical climates, the enthalpy of the air must be reduced before it can be used for cooling grain. One method of achieving this is to isothermally reduce the humidity of the air. This paper describes experiments carried out on a simple-to-build solar-regenerated open-cycle grain cooling system. The device consists of a 5.85 m{sup 2} collector coupled with two beds of silica gel. Results from a series of experiments suggest that the device may be used to cool up to 200 tons of grain. The electrical power consumption of the device is of the order of 0.3 watt per ton of grain cooled, and the total electrical energy consumption is of the order of 0.7 kWh per ton of grain stored for a six-month period. The effectiveness of the device is a function of air flow rate and the enthalpy of ambient air, and results presented in this paper suggest that the solar cooling device is particularly effective in tropical climates.

  17. Preliminary study of the potential for performance improvements in solar desiccant cooling

    NASA Astrophysics Data System (ADS)

    Schlepp, D. R.; Barlow, R.

    1981-10-01

    A second-law thermodynamic system analysis was carried out, demonstrating that present desiccant systems only achieved 10% to 15% of theoretical maximum performance and that a large potential for improvement exists. Computer simulations were used to study the effects of improving desiccant properties and increasing the effectiveness of some components of the system. Results show that modification of desiccant properties can only produce a limited (10%) increase in COP. Larger increases can be achieved by increasing the effectiveness of the sensible heat exchanger. However, it is indicated that the key to obtaining higher COPs is in the design of the dehumidifier. One design that shows promise is the parallel passage dehumidifier.

  18. Desiccant cooling system performance: A simple approach

    NASA Astrophysics Data System (ADS)

    Epstein, M.; Grolmes, M. A.

    1982-10-01

    The wave nature of heat and mass transfer in fixed desiccant bed adsorption is explained. A simple algebraic model of wave motion under single low desiccant bed operation is developed and applied to the prediction of the performance potential of the overall desiccant cooling system. The model is used to explain the increase in cooling system performance that is realized through the use of mixed inert desiccant material adsorption beds. The response of cooling system performance to changes in external process conditions is examined and conclusions are drawn relative to optimization of system characteristics.

  19. Advances in open-cycle solid desiccant cooling

    SciTech Connect

    Penney, T R; Maclaine-cross, I

    1985-05-01

    Of the solar cooling options available open cycle solid desiccant cooling looks very promising. A brief review of the experimental and analytical efforts to date shows that within the last 10 years thermal performance has doubled. Research centers have been developed to explore new materials and geometry options and to improve and validate mathematical models that can be used by design engineers to develop new product lines. Typical results from the Solar Energy Research Institute's (SERI) Desiccant Cooling Research Program are shown. Innovative ideas for new cycles and spinoff benefits provide incentives to continue research in this promising field.

  20. Options of desiccant cooling and dehumidification technology

    SciTech Connect

    Kweller, E. ); Mei, V.C.; Chen, F.C. )

    1991-01-01

    The recent CFC issue regarding the depleting of ozone layer and the greenhouse effect has become an impetus in research and development work for non-CFC air conditioning alternatives. Desiccant cooling is considered a good candidate for replacement of vapor compression chillers. A review of the present status of the desiccant based systems indicate that the technology has significantly advanced in recent years, and has become one of the most promising alternatives. New and better desiccants have been developed and novel cycles and more efficient system designs have been studied. As a result, the thermal coefficient of performance (COP) of desiccant cooling systems has been revised from around 0.6 to 1.0 or higher. These advances coupled with potentially reduced production cost could become very competitive with conventional systems in the near future. This study gives a review of the present status of desiccant materials, system designs, and computer models. 17 refs., 4 figs.

  1. Experimental studies of heat and mass exchange in parallel-passage rotary desiccant dehumidifiers for solar cooling applications

    NASA Astrophysics Data System (ADS)

    Bharathan, D.; Parsons, J. M.; Maclaine-Cross, I. L.

    1987-11-01

    This report presents results of work done to experimentally characterize the performance of rotary desiccant dehumidifiers and to develop and validate analytical methods for evaluating their performance in air-conditioning systems. A facility, the Cyclic Test Facility, and a test-and-analysis procedure were developed to evaluate the performance of the rotary dehumidifiers. Experiments were performed to develop a basic understanding of the simultaneous heat- and mass-transfer processes in the dehumidifiers. Two test articles were tested under cyclic operation to characterize their performance. Detailed accounts of the Cyclic Test Facility, its hardware and instrumentation, the two test articles, and data reduction and analysis methods are provided. The data provide an engineering data base for evaluating rotary desiccant dehumidifiers for cooling applications.

  2. Energy and economic assessment of desiccant cooling systems coupled with single glazed air and hybrid PV/thermal solar collectors for applications in hot and humid climate

    SciTech Connect

    Beccali, Marco; Finocchiaro, Pietro; Nocke, Bettina

    2009-10-15

    This paper presents a detailed analysis of the energy and economic performance of desiccant cooling systems (DEC) equipped with both single glazed standard air and hybrid photovoltaic/thermal (PV/t) collectors for applications in hot and humid climates. The use of 'solar cogeneration' by means of PV/t hybrid collectors enables the simultaneous production of electricity and heat, which can be directly used by desiccant air handling units, thereby making it possible to achieve very energy savings. The present work shows the results of detailed simulations conducted for a set of desiccant cooling systems operating without any heat storage. System performance was investigated through hourly simulations for different systems and load combinations. Three configurations of DEC systems were considered: standard DEC, DEC with an integrated heat pump and DEC with an enthalpy wheel. Two kinds of building occupations were considered: office and lecture room. Moreover, three configurations of solar-assisted air handling units (AHU) equipped with desiccant wheels were considered and compared with standard AHUs, focusing on achievable primary energy savings. The relationship between the solar collector's area and the specific primary energy consumption for different system configurations and building occupation patterns is described. For both occupation patterns, sensitivity analysis on system performance was performed for different solar collector areas. Also, this work presents an economic assessment of the systems. The cost of conserved energy and the payback time were calculated, with and without public incentives for solar cooling systems. It is worth noting that the use of photovoltaics, and thus the exploitation of related available incentives in many European countries, could positively influence the spread of solar air cooling technologies (SAC). An outcome of this work is that SAC systems equipped with PV/t collectors are shown to have better performance in terms of

  3. An assessment of dehumidifier geometries for desiccant cooling systems

    NASA Astrophysics Data System (ADS)

    Barlow, R. S.

    1983-06-01

    Dehumidifier geometries for open-cycle, solid desiccant cooling systems are assessed in order to identify those configurations which have the greatest potential of achieving performance levels that will make desiccant cooling systems economically competitive with conventional vapor-compression systems. Five dehumidifier designs are described and compared quantitatively. Compared characteristics were then related to the requirements of solar cooling application. The wound-ribbon dehumidifer design showed the highest ratio of Stanton number to friction factor and the lowest solid-side resistance to mass transfer of any geometry tested. Because of the high potential of the wound-ribbon configuration, it is recommended that further research be carried out to fully characterized this type of dehumidifier.

  4. Analysis of solar desiccant systems and concepts

    NASA Astrophysics Data System (ADS)

    Barlow, R.

    1981-05-01

    The modeling of desiccant systems is described. Computer programs for predicting the performance of silica gel beds in single-blow situations and in cyclically operating desiccant cooling systems (DESSIM) are presented. The single-blow model has been validated and shows excellent agreement with experimental data. Experimental data published by Koh are shown along with the corresponding prediction using DESSIM.

  5. Desiccant cooling: State-of-the-art assessment

    SciTech Connect

    Pesaran, A.A.; Penney, T.R.; Czanderna, A.W.

    1992-10-01

    The objectives of this document are to present an overview of the work accomplished to date on desiccant cooling to provide assessment of the state of the art of desiccant cooling technology in the field of desiccant material dehumidifier components, desiccant systems, and models. The report also discusses the factors that affect the widespread acceptance of desiccant cooling technology. This report is organized as follows. First, a basic description and historical overview of desiccant cooling technology is provided. Then, the recent research and development (R&D) program history (focusing on DOE`s funded efforts) is discussed. The status of the technology elements (materials, components, systems) is discussed in detail and a preliminary study on the energy impact of desiccant technology is presented. R&D needs for advancing the technology in the market are identified. The National Renewable Energy Laboratory`s unique desiccant test facilities and their typical outputs are described briefly. Finally, the results of a comprehensive literature search on desiccant cooling are presented in a bibliography. The bibliography contains approximately 900 citations on desiccant cooling.

  6. Desiccant cooling: State-of-the-art assessment

    SciTech Connect

    Pesaran, A.A.; Penney, T.R.; Czanderna, A.W.

    1992-10-01

    The objectives of this document are to present an overview of the work accomplished to date on desiccant cooling to provide assessment of the state of the art of desiccant cooling technology in the field of desiccant material dehumidifier components, desiccant systems, and models. The report also discusses the factors that affect the widespread acceptance of desiccant cooling technology. This report is organized as follows. First, a basic description and historical overview of desiccant cooling technology is provided. Then, the recent research and development (R D) program history (focusing on DOE's funded efforts) is discussed. The status of the technology elements (materials, components, systems) is discussed in detail and a preliminary study on the energy impact of desiccant technology is presented. R D needs for advancing the technology in the market are identified. The National Renewable Energy Laboratory's unique desiccant test facilities and their typical outputs are described briefly. Finally, the results of a comprehensive literature search on desiccant cooling are presented in a bibliography. The bibliography contains approximately 900 citations on desiccant cooling.

  7. Testing of novel desiccant materials and dehumidifier matrices for desiccant cooling applications

    SciTech Connect

    Pesaran, A.A.; Bingham, C.E.

    1989-03-01

    This paper presents the results of testing of desiccant materials and dehumidifier matrices for desiccant cooling and dehumidification applications. In testing desiccant materials, we used a gravimetric technique to measure the moisture capacity of four desiccant materials. These materials were microporous silica gel powder, macroporous silica gel powder, polystyrene sulfonic acid sodium salt, and a silica-gel/epoxy composite. The microporous silica gel powder had the most desirable moisture capacity properties of the four materials tested for desiccant cooling applications. The polystyrene sulfonic acid sodium salt showed some promise. Our testing of dehumidifier matrices included measuring the pressure drop and heat- and mass-transfer rate characteristics of a silica-gel/corrugated dehumidifier matrix under conditions typical of desiccant cooling systems. The matrix is a section of a commercial dehumidifier. The transient dehumidification capacity of the matrix was calculated from the tests and compared with previously tested matrices. 9 refs., 10 figs., 2 tabs.

  8. Desiccant dehumidification and cooling systems assessment and analysis

    SciTech Connect

    Collier, R.K. Jr.

    1997-09-01

    The objective of this report is to provide a preliminary analysis of the principles, sensitivities, and potential for national energy savings of desiccant cooling and dehumidification systems. The report is divided into four sections. Section I deals with the maximum theoretical performance of ideal desiccant cooling systems. Section II looks at the performance effects of non-ideal behavior of system components. Section III examines the effects of outdoor air properties on desiccant cooling system performance. Section IV analyzes the applicability of desiccant cooling systems to reduce primary energy requirements for providing space conditioning in buildings. A basic desiccation process performs no useful work (cooling). That is, a desiccant material drying air is close to an isenthalpic process. Latent energy is merely converted to sensible energy. Only when heat exchange is applied to the desiccated air is any cooling accomplished. This characteristic is generic to all desiccant cycles and critical to understanding their operation. The analyses of Section I show that desiccant cooling cycles can theoretically achieve extremely high thermal CoP`s (>2). The general conclusion from Section II is that ventilation air processing is the most viable application for the solid desiccant equipment analyzed. The results from the seasonal simulations performed in Section III indicate that, generally, the seasonal performance of the desiccant system does not change significantly from that predicted for outdoor conditions. Results from Section IV show that all of the candidate desiccant systems can save energy relative to standard vapor-compression systems. The largest energy savings are achieved by the enthalpy exchange devise.

  9. An assessment of desiccant cooling and dehumidification technology

    SciTech Connect

    Mei, V.C.; Chen, F.C. ); Lavan, Z. ); Collier, R.K. Jr. ); Meckler, G. )

    1992-07-01

    Desiccant systems are heat-actuated cooling and dehumidification technology. With the recent advances in this technology, desiccant systems can now achieve a primary energy coefficient of performance (COP) between 1.3 and 1.5, with potential to go to 1.7 and higher. It is becoming one of the most promising alternatives to conventional cooling systems. Two important and well-known advantages of desiccant cooling systems are that they are CFC free and they can reduce the electricity peak load. Another important but lesser-known advantage of desiccant technology is its potential for energy conservation. The energy impact study in this report indicated that a possible 13% energy saving in residential cooling and 8% in commercial cooling is possible. Great energy saving potential also exists in the industrial sector if industrial waste heat can be used for desiccant regeneration. The latest study on desiccant-integrated building heating, ventilating, and air conditioning (HVAC) systems indicated that the initial cost for the conventional cooling equipment was greatly reduced by using desiccant technology because of downsized compressors, fans, and ductworks. This cost reduction was more than enough to offset the cost of desiccant equipment. Besides, the system operation cost was also reduced. All these indicate that desiccant systems are also cost effective. This study provides an updated state-of-the-art assessment forsiccant technology in the field of desiccant materials, systems, computer models, and theoretical analyses. From this information the technology options were derived and the future research and development needs were identified. Because desiccant technology has already been applied in the commercial building sector with very encouraging results, it is expected that future market breakthroughs will probably start in this sector. A market analysis for the commercial building application is therefore included.

  10. Solar powered desiccant air conditioning system

    NASA Astrophysics Data System (ADS)

    1981-07-01

    A solar-powered desiccant air conditioning system using silica gel was developed, and modifications to the existing unit and additional testing are proposed to demonstrate the feasibility of the unit. Conversion from a rotating bed to a fixed bed of silica gel is proposed. Some general plans for commercialization are briefly discussed.

  11. Photovoltaic-electrodialysis regeneration method for liquid desiccant cooling system

    SciTech Connect

    Li, Xiu-Wei; Zhang, Xiao-Song

    2009-12-15

    Liquid desiccant cooling system (LDCS) is an (a novel) air-conditioning system with good energy saving potential. Regenerator is the power centre for LDCS. Currently, the regeneration process is always fuelled by thermal energy. Nevertheless, this regeneration pattern has some disadvantages in that its performance will become poor when the surrounding atmosphere is of high humidity, and the heat provided for regeneration will be unfavourable to the following dehumidification process. To ameliorate that, a new regeneration method is proposed in this paper: a membrane regenerator is employed to regenerate the liquid desiccant in an electrodialysis way; while solar photovoltaic generator is adopted to supply electric power for this process. Analysis has been made about this new regeneration method and the result reveals: this new manner achieves good stability with the immunity against the adverse impact from the outside high humidity; its performance is much higher than that of the thermal regeneration manner while putting aside the low efficiency of the photovoltaic system. Besides, purified water can be obtained in company with the regeneration process. (author)

  12. Development of Membrane-Based Desiccant Fiber for Vacuum Desiccant Cooling.

    PubMed

    Yang, Yifan; Rana, Dipak; Lan, Christopher Q; Matsuura, Takeshi

    2016-06-22

    A novel hydrophobic membrane-based desiccant fiber (MDF) was developed by loading lithium chloride into hydrophobic hollow fiber membranes. The MDF thus made was then tested for vapor absorption under controlled conditions. Furthermore, an MDF pad, which was made by weaving MDF into a piece of garment, was built into a laboratory vacuum desiccant cooling (VDC) setup, which included the MDF pad as the desiccant layer and a cooling towel saturated with water as the water reservoir, to test the cooling effects at atmospheric pressure and vacuum of 25 in. of Hg. Results indicate that MDF is suitable for applications such as in VDC. Mass and heat transfer of vapor absorption by MDF were also analyzed. PMID:27253330

  13. Annual DOE Active Solar Heating and Cooling Contractors Review meeting

    NASA Astrophysics Data System (ADS)

    1981-09-01

    Ninety three project summaries dicussing the following aspects of active solar heating and cooling are presented: Rankine solar cooling systems; absorption solar cooling systems; desiccant solar cooling systems; solar heat pump systems; solar hot water systems; special projects (such as the National Solar Data Network, hybrid solar thermal/photovoltaic applications, and heat transfer and water migration in soils); administrative/management support; and solar collector, storage, controls, analysis, and materials technology.

  14. Performance study of a heat recovery desiccant cooling system

    NASA Astrophysics Data System (ADS)

    Sabek, Seifennasr; Ben Nasr, Kaouther; Chouikh, Ridha; Guizani, Amenallah

    2015-04-01

    The comparison between the experimental and theoretical simulations of a desiccant cooling system under various climatic conditions (outdoor temperature and relative humidity) on the system performance has been presented. The performance of the system is evaluated using Cooling Capacity (CC) parameter. The system under a typical summer day of hot and humid climate was tested. A remarkable decrease about 40-65% in the specific humidity and with a supply air temperature lower than 25°C of the proposed system was observed. The study is important and helpful to improve the effectiveness of this kind of liquid desiccant system in hot and humid places.

  15. Potential Evaluation of Solar Heat Assisted Desiccant Hybrid Air Conditioning System

    NASA Astrophysics Data System (ADS)

    Tran, Thien Nha; Hamamoto, Yoshinori; Akisawa, Atsushi; Kashiwagi, Takao

    The solar thermal driven desiccant dehumidification-absorption cooling hybrid system has superior advantage in hot-humid climate regions. The reasonable air processing of desiccant hybrid air conditioning system and the utility of clean and free energy make the system environment friendly and energy efficient. The study investigates the performance of the desiccant dehumidification air conditioning systems with solar thermal assistant. The investigation is performed for three cases which are combinations of solar thermal and absorption cooling systems with different heat supply temperature levels. Two solar thermal systems are used in the study: the flat plate collector (FPC) and the vacuum tube with compound parabolic concentrator (CPC). The single-effect and high energy efficient double-, triple-effect LiBr-water absorption cooling cycles are considered for cooling systems. COP of desiccant hybrid air conditioning systems are determined. The evaluation of these systems is subsequently performed. The single effect absorption cooling cycle combined with the flat plate collector solar system is found to be the most energy efficient air conditioning system.

  16. Simple predictive model for performance of desiccant beds for solar dehumidification

    NASA Astrophysics Data System (ADS)

    Barlow, R.

    1981-08-01

    A computer model for the absorption/desorption process that predicts the performance of desiccant beds for solar regenerated dehumidification of passively cooled buildings is outlined. The model uses simple algebraic equations for steady state heat and mass exchangers. The validity and accuracy of the model is demonstrated. The physics of the adsorption process in two psychrometric process lines is discussed.

  17. Annual DOE active solar heating and cooling contractors' review meeting. Premeeting proceedings and project summaries

    SciTech Connect

    None,

    1981-09-01

    Ninety-three project summaries are presented which discuss the following aspects of active solar heating and cooling: Rankine solar cooling systems; absorption solar cooling systems; desiccant solar cooling systems; solar heat pump systems; solar hot water systems; special projects (such as the National Solar Data Network, hybrid solar thermal/photovoltaic applications, and heat transfer and water migration in soils); administrative/management support; and solar collector, storage, controls, analysis, and materials technology. (LEW)

  18. Colorado State University program for developing, testing, evaluating, and optimizing solar heating and cooling systems

    NASA Astrophysics Data System (ADS)

    1991-01-01

    This report discusses the following tasks: (1) solar heating with isothermal collector operation and advanced control strategy; (2) solar cooling with solid desiccant; (3) liquid desiccant cooling system development; (4) solar house III -- development and improvement of solar heating systems employing boiling liquid collectors; (5) generic solar domestic water heating systems; (6) advanced residential solar domestic hot water (DHW) systems; (7) management and coordination of Colorado State/DOE program; and (8) the field monitoring workshop.

  19. Desiccant-based, heat-actuated cooling assessment for DHC (District Heating and Cooling) systems

    SciTech Connect

    Patch, K.D.; DiBella, F.A.; Becker, F.E.

    1990-07-01

    An assessment has been completed of the use of desiccant-based, heat-actuated cooling for District Heating and Cooling (DHC) systems, showing that such desiccant-based cooling (DBC) systems are generally applicable to District Heating (DH) systems. Since the DH system only has to supply hot water (or steam) to its customers, systems that were designed as conventional two-pipe DH systems can now be operated as DHC systems without major additional capital expense. Desiccant-based DHC systems can be operated with low-grade DH-supplied heat, at temperatures below 180{degree}F, without significant loss in operating capacity, relative to absorption chillers. During this assessment, a systems analysis was performed, an experimental investigation was conducted, developmental requirements for commercializing DBC systems were examined, and two case studies were conducted. As a result of the case studies, it was found that the operating cost of a DBC system was competitive with or lower than the cost of purchasing DHC-supplied chilled water. However, because of the limited production volume and the current high capital costs of desiccant systems, the payback period is relatively long. In this regard, through the substitution of low-cost components specifically engineered for low-temperature DHC systems, the capital costs should be significantly reduced and overall economics made attractive to future users. 17 figs.

  20. Colorado State University program for developing, testing, evaluating and optimizing solar heating and cooling systems

    NASA Astrophysics Data System (ADS)

    1990-09-01

    This paper is a progress report for the period of July 1, 1990 to 31 August 1990 on activities at Colorado State University in a program for developing, testing, evaluating and optimizing solar heating and cooling systems. Topics covered are: solar heating with isothermal collectors; solid cooling with solid desiccant; liquid desiccant cooling systems; solar heating systems; solar water heaters; fields tests; and program management.

  1. Zero Carryover Liquid-Desiccant Air Conditioner for Solar Applications: Preprint

    SciTech Connect

    Lowenstein, A.; Slayzak, S.; Kozubal, E.

    2006-07-01

    A novel liquid-desiccant air conditioner that dries and cools building supply air will transform the use of direct-contact liquid-desiccant systems in HVAC applications, improving comfort, air quality, and providing energy-efficient humidity control.

  2. Desiccant grain applied to the storage of solar drying potential

    SciTech Connect

    Ziegler, T.; Richter, I.G.; Pecenka, R.

    1999-09-01

    Sorption storage of solar heat using a layer of wheat as the desiccant was analyzed by means of a deep-bed model. Intended to be applied to solar-assisted in-storage drying of agricultural bulk materials, the probability of the persistence of unfavorable weather periods was quantified statistically for Potsdam for the month of August, as an example. Simulation results demonstrate that a relative humidity of the drying air of 65% can be maintained day and night for weeks without combustion of fossil fuels. Using a simple strategy of control, periods with insufficient solar radiation can be bridged over. The desiccant grain is not endangered by mold growth as a matter of principle. Simple solar air heaters can be used to avoid economic losses due to overdrying and to reduce the danger of decay to a minimum even at unfavorable climatic conditions.

  3. Impact of ambient pressure on performance of desiccant cooling systems

    NASA Astrophysics Data System (ADS)

    Pesaran, A. A.

    1991-12-01

    The impact of ambient pressure on the performance of the ventilation cycle desiccant cooling system and its components was studied using computer simulations. The impact of ambient pressure depended on whether the system was designed for fixed-mass flow rate or fixed-volume flow rate operation. As ambient pressure decreased from 1.0 to 0.8 atm, the system thermal coefficient of performance increased by 8 pct. for both fixed-mass and fixed-volume flow rate, the cooling capacity of the system (in kW) was decreased by 14 pct. for the fixed-volume flow rate system and increased by 7 pct. for the fixed-mass flow rate system, the electric power requirements for the system with fixed-volume flow rate did not change, and the electric power requirement for the fixed-mass flow rate system increased by 44 pct. The overall coefficient of performance increased up to 5 pct. for the fixed-volume flow rate systems, and decreased up to 4 pct. for the fixed-mass flow rate system.

  4. Cool Earth Solar

    ScienceCinema

    Lamkin, Rob; McIlroy, Andy; Swalwell, Eric; Rajan, Kish

    2014-02-26

    In a public-private partnership that takes full advantage of the Livermore Valley Open Campus (LVOC) for the first time, Sandia National Laboratories and Cool Earth Solar have signed an agreement that could make solar energy more affordable and accessible. In this piece, representatives from Sandia, Cool Earth Solar, and leaders in California government all discuss the unique partnership and its expected impact.

  5. 4-rotor Desiccant Cooling Process Equipped with a Double Stage Dehumidification

    NASA Astrophysics Data System (ADS)

    Ando, Kosuke; Kodama, Akio; Okano, Hiroshi; Asada, Toshinobu

    2-rotor desiccant cooling process consisting of a honeycomb rotor dehumidifier and a sensible heat exchanger is a mainstream of the desiccant cooling process which are practically applied to supermarket, hospital and so on. However, this process cannot produce a sufficient dehumidifying performance in high humidity region. In this study, 4-rotor desiccant cooling process equipped with a double stage dehumidification was proposed and investigated experimentally. In this process, regeneration temperature around 60°C could produce a sufficient dehumidifying performance even at high ambient humidity. “Serial heat supply” mode was considered to improve the heat efficiency by the cascade use of regeneration heat inside the cooling cycle. The dehumidifying performance of the “serial heat supply” mode was only slightly lower than that of a “parallel heat supply” mode at which the same temperature hot air was supplied to the both heaters. However, dehumidifying performance of this “serial heat supply” mode was much higher than that of conventional 2-rotor desiccant cooling process. Furthermore, the desiccant rotors of 0.1m in thickness were mounted to 4-rotor desiccant cooling process in place of the 0.2m desiccant rotors. It was found that the drop of dehumidifying performance of the process equipped with 0.1m desiccant rotors was only by 10 percents comparing with the 0.2m rotor process. Moreover, it was found that optimization of rotation speed of the desiccant rotor was needed to improve the energy efficiency. Regarding the supply point of return air, it was also found that return air should be supplied to the regeneration inlet of the second stage for higher dehumidifying performance.

  6. Solar heating and cooling

    NASA Technical Reports Server (NTRS)

    Bartera, R. E.

    1978-01-01

    To emphasize energy conservation and low cost energy, the systems of solar heating and cooling are analyzed and compared with fossil fuel systems. The application of solar heating and cooling systems for industrial and domestic use are discussed. Topics of discussion include: solar collectors; space heating; pools and spas; domestic hot water; industrial heat less than 200 F; space cooling; industrial steam; and initial systems cost. A question and answer period is generated which closes out the discussion.

  7. Performance Assessment of a Desiccant Cooling System in a CHP Application with an IC Engine

    SciTech Connect

    Jalalzadeh-Azar, A. A.; Slayzak, S.; Judkoff, R.; Schaffhauser, T.; DeBlasio, R.

    2005-04-01

    Performance of a desiccant cooling system was evaluated in the context of combined heat and power (CHP). The baseline system incorporated a desiccant dehumidifier, a heat exchanger, an indirect evaporative cooler, and a direct evaporative cooler. The desiccant unit was regenerated through heat recovery from a gas-fired reciprocating internal combustion engine. The system offered sufficient sensible and latent cooling capacities for a wide range of climatic conditions, while allowing influx of outside air in excess of what is typically required for commercial buildings. Energy and water efficiencies of the desiccant cooling system were also evaluated and compared with those of a conventional system. The results of parametric assessments revealed the importance of using a heat exchanger for concurrent desiccant post cooling and regeneration air preheating. These functions resulted in enhancement of both the cooling performance and the thermal efficiency, which are essential for fuel utilization improvement. Two approaches for mixing of the return air and outside air were examined, and their impact on the system cooling performance and thermal efficiency was demonstrated. The scope of the parametric analyses also encompassed the impact of improving the indirect evaporative cooling effectiveness on the overall cooling system performance.

  8. Solid Desiccant Cooling System Employed with Ventilation Cycle: A Sensitivity Analysis

    NASA Astrophysics Data System (ADS)

    Parmar, H.; Hindoliya, D. A.

    2012-10-01

    For better use of evaporative cooling techniques in humid climate, employment of desiccant cooling system (DCS) can be a suitable option. Desiccant augmented evaporative cooling system may be employed for energy saving in buildings in place of conventional vapour compression based cooling system. This article presents a sensitive analysis of DCS simulated under the humid climate of Mumbai, India. Mathematical computations have been performed using outdoor specific humidity, ambient dry bulb temperature and room supply temperature. A sensitive analysis considering some important forcing parameters was conducted. It was observed that the "effectiveness" of direct evaporative cooler to be predominantly high influencing parameter compared to others, for the performance of DCS.

  9. Regeneration of desiccants with solar energy

    SciTech Connect

    Ghate, S.R.; Butts, C.L.; Lown, J.B.

    1985-01-01

    Saturated silica gel was regenerated with solar energy. This paper describes the experimental set-up for silica gel regeneration and data collection. The regenerated silica gel can be used to dry high moisture in-shell pecans.

  10. Research and development needs for desiccant cooling technology 1992--1997. (Supplement to the NREL report, Desiccant Cooling: State-of-the-Art Assessment)

    SciTech Connect

    Pesaran, A A

    1992-12-01

    This report is a supplement to Desiccant Cooling: State-of-the-Art Assessment (NREL/TP-254-4147, DE93000013). In this supplement document we have described a detailed program assuming sufficient funding to implement the R&D activities needed. Desiccant dehumidification is a mature technology for industrial applications, and in recent years the technology has been used for air conditioning a number of institutional and commercial buildings. Our proposal is based on argumentative discussions at various national meetings with leaders of the technology. The goal is the penetration of the broad air conditioning market. This work is funded by the Buildings technology Office of the US Department of Energy.

  11. Developing, testing, evaluating, and optimizing solar heating and cooling systems

    NASA Astrophysics Data System (ADS)

    1992-01-01

    The objective is to develop and test various integrated solar heating, cooling and domestic hot water systems, and to evaluate their performance. Systems composed of new, as well as previously tested, components are carefully integrated so that effects of new components on system performance can be clearly delineated. The SEAL-DOE program includes six tasks which have received funding for the 1991 to 92 fifteen-month period. These include: (1) a project employing isothermal operation of air and liquid solar space heating systems; (2) a project to build and test several generic solar water heaters; (3) a project that will evaluate advanced solar domestic hot water components and concepts and integrate them into solar domestic hot water systems; (4) a liquid desiccant cooling system development project; (5) a project that will perform system modeling and analysis work on solid desiccant cooling systems research; and (6) a management task. The objectives and progress in each task are described in this report.

  12. Developing, testing, evaluating and optimizing solar heating and cooling systems

    SciTech Connect

    Not Available

    1992-01-24

    The objective is to develop and test various integrated solar heating, cooling and domestic hot water systems, and to evaluate their performance. Systems composed of new, as well as previously tested, components are carefully integrated so that effects of new components on system performance can be clearly delineated. The SEAL-DOE program includes six tasks which have received funding for the 1991--92 fifteen-month period. These include: (1) a project employing isothermal operation of air and liquid solar space heating systems; (2) a project to build and test several generic solar water heaters; (3) a project that will evaluate advanced solar domestic hot water components and concepts and integrate them into solar domestic hot water systems; (4) a liquid desiccant cooling system development project; (5) a project that will perform system modeling and analysis work on solid desiccant cooling systems research; and (6) a management task. The objectives and progress in each task are described in this report.

  13. Prototype solar heating and cooling systems, including potable hot water

    NASA Technical Reports Server (NTRS)

    Bloomquist, D.; Oonk, R. L.

    1977-01-01

    Progress made in the development, delivery, and support of two prototype solar heating and cooling systems including potable hot water is reported. The system consists of the following subsystems: collector, auxiliary heating, potable hot water, storage, control, transport, and government-furnished site data acquisition. A comparison of the proposed Solaron Heat Pump and Solar Desiccant Heating and Cooling Systems, installation drawings, data on the Akron House at Akron, Ohio, and other program activities are included.

  14. Controlling rotary desiccant wheels for dehumidification and cooling

    SciTech Connect

    Crooks, K.W.; Banks, N.J.

    1996-12-31

    With greater focus on indoor air quality (IAQ) and ventilation, humidity control within spaces such as office buildings, hotels, schools, ice-skating rinks, nursing homes, and operating rooms has become paramount during the past decade. Control of relative humidity (RH) has been linked to increased comfort and the improved health of building occupants. The desiccant wheel process can be utilized in these applications to provide increased dehumidification while introducing minimal additional control parameters, often at lower cost.

  15. Open cycle liquid desiccant dehumidifier and hybrid solar/electric absorption refrigeration system. Annual report, January 1993--December 1993. Calendar year 1993

    SciTech Connect

    Nimmo, B.G.; Thornbloom, M.D.

    1995-04-01

    This annual report presents work performed during calendar year 1993 by the Florida Solar Energy Center under contract to the US Department of Energy. Two distinctively different solar powered indoor climate control systems were analyzed: the open cycle liquid desiccant dehumidifier, and an improved efficiency absorption system which may be fired by flat plate solar collectors. Both tasks represent new directions relative to prior FSEC research in Solar Cooling and Dehumidification.

  16. Research and development needs for desiccant cooling technology 1992--1997

    SciTech Connect

    Pesaran, A.A.

    1992-12-01

    This report is a supplement to Desiccant Cooling: State-of-the-Art Assessment (NREL/TP-254-4147, DE93000013). In this supplement document we have described a detailed program assuming sufficient funding to implement the R D activities needed. Desiccant dehumidification is a mature technology for industrial applications, and in recent years the technology has been used for air conditioning a number of institutional and commercial buildings. Our proposal is based on argumentative discussions at various national meetings with leaders of the technology. The goal is the penetration of the broad air conditioning market. This work is funded by the Buildings technology Office of the US Department of Energy.

  17. Zero Energy Communities with Central Solar Plants using Liquid Desiccants and Local Storage: Preprint

    SciTech Connect

    Burch, J.; Woods, J.; Kozubal, E.; Boranian, A.

    2012-08-01

    The zero energy community considered here consists of tens to tens-of-thousands of residences coupled to a central solar plant that produces all the community's electrical and thermal needs. A distribution network carries fluids to meet the heating and cooling loads. Large central solar systems can significantly reduce cost of energy vs. single family systems, and they enable economical seasonal heat storage. However, the thermal distribution system is costly. Conventional district heating/cooling systems use a water/glycol solution to deliver sensible energy. Piping is sized to meet the peak instantaneous load. A new district system introduced here differs in two key ways: (i) it continuously distributes a hot liquid desiccant (LD) solution to LD-based heating and cooling equipment in each home; and (ii) it uses central and local storage of both LD and heat to reduce flow rates to meet average loads. Results for piping sizes in conventional and LD thermal communities show that the LD zero energy community reduces distribution piping diameters meeting heating loads by {approx}5X and meeting cooling loads by {approx}8X for cooling, depending on climate.

  18. Competitive assessment of desiccant solar/gas systems for single family residences

    NASA Astrophysics Data System (ADS)

    1982-01-01

    The solar/gas desiccant space conditioning system was compared with competing gas and electric technologies. Benefits and costs to the residential gas customer were evaluated, and practical recommendations regarding an appropriate R&D agenda to maximize the probability of successful development of an advanced desiccant system for that market were provided.

  19. Low cost solar energy collection for cooling applications

    NASA Astrophysics Data System (ADS)

    Wilhelm, W. G.

    1981-06-01

    Solar energy collector designs utilizing thin-film polymeric materials in the absorber and glazing are investigated. The main objective is dramatic cost reduction consistent with acceptable performance and life. These collectors now appear capable of high temperature applications including desiccant and absorption cooling (1500 to 2000 F). The performance and economics of the thin-film collector are compared with those of conventional flat-plate designs in cooling applications.

  20. Solar air conditioning with solid absorbents and earth cooling

    NASA Astrophysics Data System (ADS)

    Mayer, E.

    An experimental design is described for an efficient desiccant cooling system using natural cold sink to reduce the moisture content of the ambient air. Used in a warm, humid, tropical climate, the unit is shown to provide up to 0.77 ton of refrigeration under extreme conditions with an average daily coefficient of performance of 0.5. Solar heat is applied to regenerate the silica gel.

  1. The second-law analysis of a recirculation cycle desiccant cooling system: Cosorption of water vapor and carbon dioxide

    NASA Astrophysics Data System (ADS)

    Shen, C. M.; Worek, W. M.

    The second law, of thermodynamics is applied to a desiccant cooling system operating in the recirculation mode. In this study, the adsorbent is 13X molecular sieve, and the process air stream is assumed to contain only dry air, water vapor, and carbon dioxide. The second law efficiencies of a desiccant wheel are documented in terms of overall number of transfer units and the regeneration temperature. The results show that based on the first law and second law of thermodynamics, a solid desiccant adsorber using 13X molecular sieve can be optimally designed.

  2. Energy and economic performance analysis of an open cycle solar desiccant dehumidification air-conditioning system for application in Hong Kong

    SciTech Connect

    Li, Yutong; Lu, Lin; Yang, Hongxing

    2010-12-15

    In this article, a transient simulation model and the EnergyPlus were used to study the energy performance and economical feasibility for integrating a solar liquid desiccant dehumidification system with a conventional vapor compression air-conditioning system for the weather condition of Hong Kong. The vapor compression system capacity in the solar assisted air-conditioning system can be reduced to 19 kW from original 28 kW of a conventional air-conditioning system as a case study due to the solar desiccant cooling. The economical performance of the solar desiccant dehumidification system is compared with that of the conventional air-conditioning system. The results show that the energy saving potentials due to incorporation of the solar desiccant dehumidification system in a traditional air-conditioning system is significant for the hot wet weather in Hong Kong due to higher COP resulted from higher supply chilled water temperature from chiller plants. The annual operation energy savings for the hybrid system is 6760 kWh and the payback period of the hybrid system is around 7 years. The study shows that the solar assisted air-conditioning is a viable technology for utilizations in subtropical areas. (author)

  3. A packed bed dehumidifier/regenerator for solar air conditioning with liquid desiccants

    NASA Astrophysics Data System (ADS)

    Factor, H. M.; Grossman, G.

    1980-01-01

    A packed column air-liquid contactor has been studied in application to air dehumidification and regeneration in solar air conditioning with liquid desiccants. A theoretical model has been developed to predict the performance of the device under various operating conditions. Computer simulations based on the model are presented which indicate the practical range of air to liquid flux ratios and associated changes in air humidity and desiccant concentration. An experimental apparatus has been constructed and experiments performed with Monoethylene Glycol (MEG) and Lithium Bromide as desiccants. MEG experiments have yielded inaccurate results and have pointed out some practical problems associated with the use of Glycols. LiBr experiments show very good agreement with the theoretical model. Preheating of the air is shown to greatly enhance desiccant regeneration. The packed column yields good results as a dehumidifier/regenerator, provided pressure drop can be reduced with the use of suitable packing.

  4. Comparative study of different solar cooling systems for buildings in subtropical city

    SciTech Connect

    Fong, K.F.; Chow, T.T.; Lee, C.K.; Lin, Z.; Chan, L.S.

    2010-02-15

    In recent years, more and more attention has been paid on the application potential of solar cooling for buildings. Due to the fact that the efficiency of solar collectors is generally low at the time being, the effectiveness of solar cooling would be closely related to the availability of solar irradiation, climatic conditions and geographical location of a place. In this paper, five types of solar cooling systems were involved in a comparative study for subtropical city, which is commonly featured with long hot and humid summer. The solar cooling systems included the solar electric compression refrigeration, solar mechanical compression refrigeration, solar absorption refrigeration, solar adsorption refrigeration and solar solid desiccant cooling. Component-based simulation models of these systems were developed, and their performances were evaluated throughout a year. The key performance indicators are solar fraction, coefficient of performance, solar thermal gain, and primary energy consumption. In addition, different installation strategies and types of solar collectors were compared for each kind of solar cooling system. Through this comparative study, it was found that solar electric compression refrigeration and solar absorption refrigeration had the highest energy saving potential in the subtropical Hong Kong. The former is to make use of the solar electric gain, while the latter is to adopt the solar thermal gain. These two solar cooling systems would have even better performances through the continual advancement of the solar collectors. It will provide a promising application potential of solar cooling for buildings in the subtropical region. (author)

  5. Colorado State University program for developing, testing, evaluating and optimizing solar heating and cooling systems

    NASA Astrophysics Data System (ADS)

    1993-01-01

    This program includes six tasks. The tasks are as follows: (1) a project measuring the performance of unique solar system components; (2) a project to develop a methodology for determining annual performance ratings of solar domestic hot water systems; (3) a project that will identify, analyze, design, build, and experimentally evaluate SDHW systems incorporating advanced concepts and components; (4) a liquid desiccant cooling system development project; (5) a project that will perform TRNSYS simulations to determine potential energy savings for desiccant cooling systems, especially in humid climates; and (6) a management task. The objectives and progress in each task are described.

  6. Colorado State University program for developing, testing, evaluating and optimizing solar heating and cooling systems

    SciTech Connect

    Not Available

    1993-01-07

    This program includes six tasks, including (1) a project measuring the performance of unique solar system components, (2) a project to develop a methodology for determining annual performance ratings of solar domestic hot water systems, (3) a project that will identify, analyze, design, build, and experimentally evaluate SDHW systems incorporating advanced concepts and components, (4) a liquid desiccant cooling system development project, (5) a project that will perform TRNSYS simulations to determine potential energy savings for desiccant cooling systems, especially in humid climates, and (6) a management task. The objectives and progress in each task are described.

  7. Developing, testing, evaluating and optimizing solar heating and cooling systems

    SciTech Connect

    Not Available

    1991-11-01

    The objective is to develop and test various integrated solar heating, cooling and domestic hot water systems, and to evaluate their performance. Systems composed of new, as well a previously tested, components are carefully integrated so that effects of new components on system performance can be clearly delineated. The SEAL-DOE program includes six tasks which have received funding for the 1991--1992 fifteen-month period. These include: (1) a project employing isothermal operation of air and liquid solar space hearing systems, (2) a project to build and test several generic solar water heaters, (3) a project that will evaluate advanced solar domestic hot water components and concepts and integrate them into solar domestic hot water systems, (4) a liquid desiccant cooling system development project, (5) a project that will perform system modeling and analysis work on solid desiccant cooling systems research, and (6) a management task. The objectives and progress in each task are described in this report. 6 figs., 2 tabs.

  8. Double-stage Dehumidification achieved in 2-rotor Desiccant Cooling Process

    NASA Astrophysics Data System (ADS)

    Asada, Toshinobu; Kodama, Akio

    A multi-divided rotary adsorber was proposed to realize a double-stage dehumidification in 2-rotor desiccant cooling process. In this process, once dehumidified and cooled air was dehumidified again at the different adsorption zone of the same desiccant rotor. Four process flow configurations were experimentally tested for investigations of the appropriate outside air inlet position and rotating directions of the rotary adsorber and rotary heat exchanger. It was found that dehumidifying performance was strongly influenced by the supply position of outside air to the adsorbent rotor. Humid outside air should be supplied to the latter half of the adsorption zone and once dehumidified air should be sent to the first half of the adsorption zone. This is because the increase in the amount adsorbed at the first half of the adsorption step resulted in a poor adsorbabilty at the latter half of the adsorption step for the once dehumidified dry air. Therefore, the effective use of the adsorbent rotor could be done by considering the angular distribution of the amount of adsorbed. Consequently, 30% larger amount of dehumidification than that of conventional processes under a humid summer condition was confirmed. Regarding the product air temperature, the process configurations at which secondary dehumidified air was cooled at the first half of the sensible rotor produced roughly 5 °C lower temperature air than that of the other. This implied that the directions of rotation of the adsorbent rotor and the rotary heat exchanger, or dehumidification - cooling sequence, also had a great impact on the product air condition.

  9. Solar Heating and Cooling

    ERIC Educational Resources Information Center

    Duffie, John A.; Beckman, William A.

    1976-01-01

    Describes recent research that has made solar energy economically competitive with other energy sources. Includes solar energy building architecture, storage systems, and economic production data. (MLH)

  10. Desiccant contamination research: Report on the desiccant contamination test facility

    SciTech Connect

    Pesaran, A.A.; Bingham, C.E.

    1991-07-01

    The activity in the cooling systems research involves research on high performance dehumidifiers and chillers that can operate efficiently with the variable thermal outputs and delivery temperatures associated with solar collectors. It also includes work on advanced passive cooling techniques. This report describes the work conducted to improve the durability of solid desiccant dehumidifiers by investigating the causes of degradation of desiccant materials from airborne contaminants and thermal cycling. The performance of a dehumidifier strongly depends on the physical properties and durability of the desiccant material. To make durable and reliable dehumidifiers, an understanding is needed of how and to what degree the performance of a dehumidifier is affected by desiccant degradation. This report, an account of work under Cooling Systems Research, documents the efforts to design and fabricate a test facility to investigate desiccant contamination based on industry and academia recommendations. It also discusses the experimental techniques needed for obtaining high-quality data and presents plans for next year. Researchers of the Mechanical and Industrial Technology Division performed this work at the Solar Energy Research Institute in FY 1988 for DOE's Office of Solar Heat Technologies. 7 refs., 19 figs., 1 tab.

  11. Colorado State University program for developing, testing, evaluating and optimizing solar heating, and cooling systems

    NASA Astrophysics Data System (ADS)

    1991-10-01

    The objective is to develop and test various integrated solar heating, cooling and domestic hot water systems, and to evaluate their performance. Systems composed of new, as well as previously tested, components are carefully integrated so that effects of new components on system performance can be clearly delineated. The SEAL-DOE program includes six tasks which have received funding for the 1991 to 1992 fifteen month period. These include: (1) a project employing isothermal operation of air and liquid solar space heating systems; (2) a project to build and test several generic solar water heaters; (3) a project that will evaluate advanced solar domestic hot water components and concepts and integrate them into solar domestic hot water systems; (4) a liquid desiccant cooling system development project; (5) a project that will perform system modeling and analysis work on solid desiccant cooling systems research; and (6) a management task. The objectives and progress in each task are described in this report.

  12. Effective Operation for an Adsorptive Desiccant Cooling Process using a Double-Stage Regeneration of Honeycomb Rotary Dehumidifier

    NASA Astrophysics Data System (ADS)

    Kodama, Akio; Ando, Kouke; Hirose, Tsutomu; Goto, Motonobu; Tuziguchi, Takuya; Okano, Hiroshi

    A double-stage regeneration concept has been applied to a rotary dehumidifier to achieve a high efficient desiccant cooling process. In this concept, regeneration zone of the dehumidifier was divided into two zones. One was pre-regeneration zone where the desiccant rotor was regenerated by warm air heated at the sensible heat exchanger, and the other was heating regeneration zone where the rotor was further regenerated by hot air heated up to the controlled temperature at a heating system. In this paper, the influence of the area ratio of these two zones on the dehumidifying/cooling performance and energy efficiency of this desiccant system were mainly discussed at several levels of the regeneration temperature, supply air velocity and inlet air humidity. Experimental results indicated that the area ratio of the heating regeneration zone should be optimized to produce a sufficient dehumidifying/cooling performance with high energy efficiency, considering humidity requested in supply air. It was also found that the amount of energy input was rather decreased than the decrease of the cooling performance as the area ratio of the heating regeneration zone decreased, and this tendency was more remarkable at higher regeneration temperature. Finally, the double-stage regeneration was confirmed to be an effective operating method for the desiccant cooling process equipped with a otary dehumidifier.

  13. Colorado State University program for developing, testing, evaluation and optimizing solar heating and cooling systems. Project status report, August--September 1993

    SciTech Connect

    Not Available

    1993-09-01

    This report describes activities of the Colorado State University program on solar heating and cooling systems for the months of August and September 1993. The topics include: rating and certification of domestic water heating systems, unique solar system components, advanced residential solar domestic hot water systems, and desiccant cooling of buildings.

  14. Experiences in solar cooling systems

    NASA Astrophysics Data System (ADS)

    Ward, D. S.

    The results of performance evaluations for nine solar cooling systems are presented, and reasons fow low or high net energy balances are discussed. Six of the nine systems are noted to have performed unfavorably compared to standard cooling systems due to thermal storage losses, excessive system electrical demands, inappropriate control strategies, poor system-to-load matching, and poor chiller performance. A reduction in heat losses in one residential unit increased the total system efficiency by 2.5%, while eliminating heat losses to the building interior increased the efficiency by 3.3%. The best system incorporated a lithium bromide absorption chiller and a Rankine cycle compression unit for a commercial application. Improvements in the cooling tower and fan configurations to increase the solar cooling system efficiency are indicated. Best performances are expected to occur in climates inducing high annual cooling loads.

  15. Moving Advanced Desiccant Materials into Mainstream Non-CFC Cooling Products

    SciTech Connect

    Sand, J R; Grossman, G; Rice, C K; Fairchild, P D; Gross, I L

    1994-01-01

    Desiccant air-conditioning systems can be used as alternatives for conventional air-conditioning equipment in any commercial or residential building. Recent breakthroughs in desiccant materials technology and the creation of new markets by Indoor Air Quality issues make desiccant-based air-conditioning equipment practical for many space-conditioning applications.

  16. Economic and technical assessment of the desiccant wheel effect on the thermal performance of cross flow cooling towers in variable wet bulb temperature

    NASA Astrophysics Data System (ADS)

    Banooni, Salem; Chitsazan, Ali

    2014-05-01

    Performance improvements of cross flow cooling towers in variable wet bulb temperature were performed. A conventional mathematical model is used to predict desiccant wheel effect on the performance of cooling tower. It is found that by using optimum parameters of desiccant wheel, the inlet air wet bulb temperature into the cooling tower would decrease more than 6 °C and outlet water temperature would decrease more than 4 °C.

  17. Solar-powered cooling system

    DOEpatents

    Farmer, Joseph C

    2013-12-24

    A solar-powered adsorption-desorption refrigeration and air conditioning system uses nanostructural materials made of high specific surface area adsorption aerogel as the adsorptive media. Refrigerant molecules are adsorbed on the high surface area of the nanostructural material. A circulation system circulates refrigerant from the nanostructural material to a cooling unit.

  18. Anisotropic stress accumulation in cooling lava flows and resulting fracture patterns: Insights from starch-water desiccation experiments

    NASA Astrophysics Data System (ADS)

    Lodge, Robert W. D.; Lescinsky, David T.

    2009-09-01

    Desiccation of starch-water slurries is a useful analog for the production of polygonal fractures/columnar joints in cooling lava flows. When left to dry completely, a simple mixture of 1:1 starch and water will produce columns that appear remarkably similar to natural columnar joints formed in cooled lava flows. Columns form when the accumulation of isotropic stress exceeds the tensile strength of a material, at which point a fracture forms and advances through the material perpendicular to the desiccating surface. Individual fractures will initially form orthogonal to the desiccation surface but will quickly evolve into a hexagonal fracture network that advances incrementally through the material. However, some fracture patterns found within natural lava flows are not hexagonal ( Lodge and Lescinsky, 2009-this issue), but rather have fracture lengths that are much longer than the distance to adjacent fractures. These fractures are commonly found at lava flows that have interacted with glacial ice during emplacement. The purpose of this study is to utilize starch analog experiments to better understand the formation of these fractures and the stress regimes responsible for their non-hexagonal patterns. To simulate anisotropic conditions during cooling, the starch slurry was poured into a container with a movable wall that was attached to a screw-type jack. The jack was then set to slowly extend or retract while the slurry desiccated. This resulted in either a decrease or increase in the chamber cross-sectional area thus creating compressional or extensional regimes. Decreasing chamber area (DCA) experiments resulted in fractures with larger lengths parallel to the direction of wall movement (also direction of compression). It also caused localized thrust faulting and curved column development. Increasing chamber area (ICA) experiments produced a zone of horizontal column development along the expanding margin (produced when the wall detached from the sample

  19. Terrestrial cooling and solar variability

    NASA Technical Reports Server (NTRS)

    Agee, E. M.

    1982-01-01

    Observational evidence from surface temperature records is presented and discussed which suggests a significant cooling trend over the Northern Hemisphere from 1940 to the present. This cooling trend is associated with an increase of the latitudinal gradient of temperature and the lapse rate, as predicted by climate models with decreased solar input and feedback mechanisms. Evidence suggests that four of these 80- to 100-year cycles of global surface temperature fluctuation may have occurred, and in succession, from 1600 to the present. Interpretation of sunspot activity were used to infer a direct thermal response of terrestrial temperature to solar variability on the time scale of the Gleissberg cycle (90 years, an amplitude of the 11-year cycles). A physical link between the sunspot activity and the solar parameter is hypothesized. Observations of sensible heat flux by stationary planetary waves and transient eddies, as well as general circulation modeling results of these processes, were examined from the viewpoint of the hypothesis of cooling due to reduced insolation.

  20. Colorado State University Program for developing, testing, evaluating and optimizing solar heating and cooling systems. Project status report, October--November 1993

    SciTech Connect

    Not Available

    1993-12-01

    Progress is reported in the areas of: Rating and certification of domestic water heating systems, unique solar system components, advanced residential solar domestic hot water systems, analysis of advanced desiccant solar cooling systems, and management and coordination of Colorado State/DOE program.

  1. Developing, testing, evaluating and optimizing solar heating and cooling systems. Project status report, November--December 1991

    SciTech Connect

    Not Available

    1992-01-24

    The objective is to develop and test various integrated solar heating, cooling and domestic hot water systems, and to evaluate their performance. Systems composed of new, as well as previously tested, components are carefully integrated so that effects of new components on system performance can be clearly delineated. The SEAL-DOE program includes six tasks which have received funding for the 1991--92 fifteen-month period. These include: (1) a project employing isothermal operation of air and liquid solar space heating systems; (2) a project to build and test several generic solar water heaters; (3) a project that will evaluate advanced solar domestic hot water components and concepts and integrate them into solar domestic hot water systems; (4) a liquid desiccant cooling system development project; (5) a project that will perform system modeling and analysis work on solid desiccant cooling systems research; and (6) a management task. The objectives and progress in each task are described in this report.

  2. Early developments in solar cooling equipment

    NASA Technical Reports Server (NTRS)

    Price, J. M.

    1978-01-01

    A brief description of a development program to design, fabricate and field test a series of solar operated or driven cooling devices, undertaken by the Marshall Space Flight Center in the context of the Solar Heating and Cooling Demonstration Act of 1974, is presented. Attention is given to two basic design concepts: the Rankine cycle principle and the use of a dessicant for cooling.

  3. Solar heating and cooling buildings

    NASA Technical Reports Server (NTRS)

    1973-01-01

    Sunshine is available in differing amounts everywhere in the world and the easiest method of capturing it is by absorption in the form of thermal energy (heat). Therefore, it is logical to utilize it directly in the heating and cooling of buildings and avoid losses that would occur by conversion to some other form. It may be emphasized that of the total energy consumed annually in the U.S., about 25% is used for heating and cooling in buildings. It is generally agreed that of all the possible widespread uses of solar energy, this application has the highest probability of success in the near term. Although there are significant uncertainties associated with some technological and economic aspects, they do not loom as large as those associated with other potentially significant applications, such as electrical power generation. It may, however, be noted that solar electrical power generation at the building site, or at a centralized station is an excellent long term prospect. Approximately 25 experimental solar heated structures have been built in various parts of the world.

  4. Testing and design of solar cooling systems employing liquid dessicants

    SciTech Connect

    Lenz, T.; Loef, G.O.G.; Flaherty, M.; Misra, S.; Patnaik, S.

    1989-05-01

    An open cycle liquid desiccant cooling system with cooling capacity of 3 tons (10.5 kW) a subject of research at Colorado State University. The system comprises two main units: the dehumidifier and the regenerator. Lithium bromide is the desiccant solution that dehumidifies the air stream during a counter-current, liquid-gas contacting in the packed tower. The regenerator concentrates the lithium bromide solution during a similar gas-liquid contacting using solar heated air with the only difference being that the direction of heat and mass transfer are reversed in this unit. The earlier studies conducted on the dehumidifier revealed significant departures from an energy balance closure. An attempt has been made to provide a realistic energy balance closure to the dehumidifier side. This has resulted in substantial re-calibration of the major instruments involved. Performance data of the entire system with the regenerator and dehumidifier operated in coupled mode have been presented. An optimization scheme to predict operating conditions suited for best performance of the two units, for varying ambient temperature and humidity to the dehumidifier, has been devised. 15 refs., 20 figs., 8 tabs.

  5. Solar-powered cooling system

    SciTech Connect

    Farmer, Joseph C.

    2015-07-28

    A solar-powered adsorption-desorption refrigeration and air conditioning system that uses nanostructural materials such as aerogels, zeolites, and sol gels as the adsorptive media. Refrigerant molecules are adsorbed on the high surface area of the nanostructural material while the material is at a relatively low temperature, perhaps at night. During daylight hours, when the nanostructural materials is heated by the sun, the refrigerant are thermally desorbed from the surface of the aerogel, thereby creating a pressurized gas phase in the vessel that contains the aerogel. This solar-driven pressurization forces the heated gaseous refrigerant through a condenser, followed by an expansion valve. In the condenser, heat is removed from the refrigerant, first by circulating air or water. Eventually, the cooled gaseous refrigerant expands isenthalpically through a throttle valve into an evaporator, in a fashion similar to that in more conventional vapor recompression systems.

  6. Effect of Water Spray Evaporative Cooling at the Inlet of Regeneration Air Stream on the Performance of an Adsorption Desiccant Cooling Process

    NASA Astrophysics Data System (ADS)

    Ando, Kosuke; Kodama, Akio; Hirose, Tsutomu; Goto, Motonobu; Okano, Hiroshi

    This paper shows an influence of evaporative cooler at the inlet of regeneration air stream of an adsorptive desiccant cooling process on the cooling/dehumidifying performance. This evaporative cooling was expected to cause humidity increase in regeneration air reducing the dehumidifying performance of the honeycomb absorber, while the evaporative cooling plays an important role to produce a lower temperature in supply air. Two different airs to be used for the regeneration of the desiccant wheel were considered. One was fresh outside air (OA mode) and the other was air ventilated from the room (RA mode). Experimental results showed that the amount of dehumidified water obtained at the process without water spray evaporative cooler was actually larger than that of process with water spray evaporative cooler. This behavior was mainly due to increase of humidity or relative humidity in the regeneration air as expected. However, temperature of supply air produced by the process with the evaporator was rather lower than that of the other because of the cooled return air, resulting higher CE value. Regarding the operating mode, the evaporative cooler at the OA-mode was no longer useful at higher ambient humidity because of the difficulty of the evaporation of the water in such high humidity. It was also found that its dehumidifying performance was remarkably decreased at higher ambient humidity and lower regeneration temperature since the effective adsorption capacity at the resulting high relative humidity of the regeneration air decreased.

  7. Seminar 14 - Desiccant Enhanced Air Conditioning: Desiccant Enhanced Evaporative Air Conditioning (Presentation)

    SciTech Connect

    Kozubal, E.

    2013-02-01

    This presentation explains how liquid desiccant based coupled with an indirect evaporative cooler can efficiently produce cool, dry air, and how a liquid desiccant membrane air conditioner can efficiently provide cooling and dehumidification without the carryover problems of previous generations of liquid desiccant systems. It provides an overview to a liquid desiccant DX air conditioner that can efficiently provide cooling and dehumidification to high latent loads without the need for reheat, explains how liquid desiccant cooling and dehumidification systems can outperform vapor compression based air conditioning systems in hot and humid climates, explains how liquid desiccant cooling and dehumidification systems work, and describes a refrigerant free liquid desiccant based cooling system.

  8. Advances in Solar Heating and Cooling Systems

    ERIC Educational Resources Information Center

    Ward, Dan S.

    1976-01-01

    Reports on technological advancements in the fields of solar collectors, thermal storage systems, and solar heating and cooling systems. Diagrams aid in the understanding of the thermodynamics of the systems. (CP)

  9. Solar-Powered, Liquid-Desiccant Air Conditioner for Low-Electricity Humidity Control: Report and Summary Report

    SciTech Connect

    Dean, J.; Kozubal, E.; Herrmann, L.; Miller, J.; Lowenstein, A.; Barker, G.; Slayzak, S.

    2012-11-01

    The primary objective of this project was to demonstrate the capabilities of a new high-performance, liquid-desiccant dedicated outdoor air system (DOAS) to enhance cooling efficiency and comfort in humid climates while substantially reducing electric peak demand at Tyndall Air Force Base (AFB), which is 12 miles east of Panama City, Florida.

  10. Solar technology assessment project. Volume 4: Solar air conditioning: Active, hybrid and passive

    NASA Astrophysics Data System (ADS)

    Yellott, J. I.

    1981-04-01

    The status of absorption cycle solar air conditioning and the Rankine cycle solar cooling system is reviewed. Vapor jet ejector chillers, solar pond based cooling, and photovoltaic compression air conditioning are also briefly discussed. Hybrid solar cooling by direct and indirect evaporative cooling, and dehumidification by desiccation are described and discussed. Passive solar cooling by convective and radiative processes, evaporative cooling by passive processes, and cooling with roof ponds and movable insulation are reviewed. Federal and state involvement in solar cooling is discussed.

  11. Moving Advanced Desiccant Materials into Mainstream Non-CFC Cooling Products

    SciTech Connect

    Sand, J. R.; Grossman, T.; Rice, C. K.; Fairchild, P. D.; Gross, I. L.

    2004-12-30

    Desiccant dehumidification technology is emerging as a technically viable alternative for comfort conditioning in many commercial and institutional buildings. Attempts to improve the indoor air quality of buildings has resulted in increasingly stringent guidelines for occupant outdoor air ventilation rates. Additionally, revised building heating, ventilating, and air-conditioning (HVAC) design criteria based on regional peak dew point data highlight the important of the latent (moisture removal) building load relative to the sensible (temperature) building load.

  12. The economics of solar powered absorption cooling

    NASA Technical Reports Server (NTRS)

    Bartlett, J. C.

    1978-01-01

    Analytic procedure evaluates cost of combining absorption-cycle chiller with solar-energy system in residential or commercial application. Procedure assumes that solar-energy system already exists to heat building and that cooling system must be added. Decision is whether to cool building with conventional vapor-compression-cycle chiller or to use solar-energy system to provide heat input to absorption chiller.

  13. Polymers as advanced materials for desiccant applications, 1988

    SciTech Connect

    Czanderna, A.W.; Neidlinger, H.H.

    1990-09-01

    This report documents work to identify a next-generation, low-cost material with which solar energy or heat from another low-cost energy source can be used for regenerating the water vapor sorption activity of the desiccant. The objective of the work is to determine how the desired sorption performance of advanced desiccant materials can be predicted by understanding the role of the material modifications and material surfaces. The work concentrates on solid materials to be used for desiccant cooling systems and which process water vapor in an atmosphere to produce cooling. The work involved preparing modifications of polystyrene sulfonic acid sodium salt, synthesizing a hydrogel, and evaluating the sorption performances of these and similar commercially available polymeric materials; all materials were studied for their potential application in solid commercial desiccant cooling systems. Background information is also provided on desiccant cooling systems and the role of a desiccant material within such a system, and it includes the use of polymers as desiccant materials. 31 refs., 16 figs., 5 tabs.

  14. Colorado State University program for developing, testing, evaluating and optimizing solar heating and cooling systems. Project status report, March--November 1992

    SciTech Connect

    Not Available

    1993-01-07

    This program includes six tasks, including (1) a project measuring the performance of unique solar system components, (2) a project to develop a methodology for determining annual performance ratings of solar domestic hot water systems, (3) a project that will identify, analyze, design, build, and experimentally evaluate SDHW systems incorporating advanced concepts and components, (4) a liquid desiccant cooling system development project, (5) a project that will perform TRNSYS simulations to determine potential energy savings for desiccant cooling systems, especially in humid climates, and (6) a management task. The objectives and progress in each task are described.

  15. Solar heating and cooling of buildings

    NASA Technical Reports Server (NTRS)

    Bourke, R. D.; Davis, E. S.

    1975-01-01

    Solar energy has been used for space heating and water heating for many years. A less common application, although technically feasible, is solar cooling. This paper describes the techniques employed in the heating and cooling of buildings, and in water heating. The potential for solar energy to displace conventional energy sources is discussed. Water heating for new apartments appears to have some features which could make it a place to begin the resurgence of solar energy applications in the United States. A project to investigate apartment solar water heating, currently in the pilot plant construction phase, is described.

  16. Desiccant Enhanced Evaporative Air-Conditioning (DEVap): Evaluation of a New Concept in Ultra Efficient Air Conditioning

    SciTech Connect

    Kozubal, E.; Woods, J.; Burch, J.; Boranian, A.; Merrigan, T.

    2011-01-01

    NREL has developed the novel concept of a desiccant enhanced evaporative air conditioner (DEVap) with the objective of combining the benefits of liquid desiccant and evaporative cooling technologies into an innovative 'cooling core.' Liquid desiccant technologies have extraordinary dehumidification potential, but require an efficient cooling sink. DEVap's thermodynamic potential overcomes many shortcomings of standard refrigeration-based direct expansion cooling. DEVap decouples cooling and dehumidification performance, which results in independent temperature and humidity control. The energy input is largely switched away from electricity to low-grade thermal energy that can be sourced from fuels such as natural gas, waste heat, solar, or biofuels.

  17. Colorado State University program for developing, testing, evaluating and optimizing solar heating and cooling systems

    SciTech Connect

    Not Available

    1991-10-28

    The objective is to develop and test various integrated solar heating, cooling and domestic hot water systems, and to evaluate their performance. Systems composed of new, as well as previously tested, components are carefully integrated so that effects of new components on system performance can be clearly delineated. The SEAL-DOE program includes six tasks which have received funding for the 1991--92 fifteen-month period. These include: (1) a project employing isothermal operation of air and liquid solar space heating systems; (2) a project to build and test several generic solar water heaters; (3) a project that will evaluate advanced solar domestic hot water components and concepts and integrate them into solar domestic hot water systems; (4) a liquid desiccant cooling system development project; (5) a project that will perform system modeling and analysis work on solid desiccant cooling systems research; and (6) a management task. The objectives and progress in each task are described in this report. 6 figs.

  18. Rankine-cycle solar-cooling systems

    NASA Technical Reports Server (NTRS)

    Weathers, H. M.

    1979-01-01

    Report reviews progress made by three contractors to Marshall Space Flight Center and Department of Energy in developing Rankine-cycle machines for solar cooling and testing of commercially available equipment involved.

  19. Solar Heating and Cooling Development Program

    NASA Technical Reports Server (NTRS)

    Aaen, R.; Gossler, A.

    1984-01-01

    Heating is practical now, but cooling needs more development. Report describes program for design and development of solar heating and cooling systems having high performance, low cost and modular application. Describes main technical features of each of systems. Presents summary of performance and costs.

  20. Solar Heating and Cooling: An Economic Assessment.

    ERIC Educational Resources Information Center

    McGarity, Arthur E.

    This study serves as an introduction to the important economic considerations that are necessary for an assessment of the potential for solar heating and cooling in the United States. The first chapter introduces the technology that is used to tap solar energy for residential and commercial applications and illustrates the potential significance…

  1. Solar heating and cooling: Technical data and systems analysis

    NASA Technical Reports Server (NTRS)

    Christensen, D. L.

    1975-01-01

    The solar energy research is reported including climatic data, architectural data, heating and cooling equipment, thermal loads, and economic data. Lists of data sources presented include: selected data sources for solar energy heating and cooling; bibliography of solar energy, and other energy sources; sources for manufacturing and sales, solar energy collectors; and solar energy heating and cooling projects.

  2. Solar absorption cooling plant in Seville

    SciTech Connect

    Bermejo, Pablo; Pino, Francisco Javier; Rosa, Felipe

    2010-08-15

    A solar/gas cooling plant at the Engineering School of Seville (Spain) was tested during the period 2008-2009. The system is composed of a double-effect LiBr + water absorption chiller of 174 kW nominal cooling capacity, powered by: (1) a pressurized hot water flow delivered by mean of a 352 m{sup 2} solar field of a linear concentrating Fresnel collector and (2) a direct-fired natural gas burner. The objective of the project is to indentify design improvements for future plants and to serve as a guideline. We focused our attention on the solar collector size and dirtiness, climatology, piping heat losses, operation control and coupling between solar collector and chiller. The daily average Fresnel collector efficiency was 0.35 with a maximum of 0.4. The absorption chiller operated with a daily average coefficient of performance of 1.1-1.25, where the solar energy represented the 75% of generator's total heat input, and the solar cooling ratio (quotient between useful cooling and insolation incident on the solar field) was 0.44. (author)

  3. Solar cooling in Madrid: Available solar energy

    SciTech Connect

    Izquierdo, M.; Hernandez, F.; Martin, E. )

    1994-11-01

    This paper analyzes the behaviour of an absorption chiller lithium bromide installation fed by a field of flat-plate solar collectors and condensed by swimming pool water. A method of calculation in a variable regime is developed in terms of the obtained experimental results. Starting from the meteorological variables of a clear summer day and from the project data (collector normalization curve, collector and installation mass), the minimum solar radiation level necessary to initiate the process, I[sub min], and the instantaneous available solar energy, Q[sub u] + W[sub 1] is determined. The solar radiation threshold, I[sub min], necessary to obtain the process temperature, t[sub ave], in each instant, is obtained by adding to the corrected Klein radiation threshold, I[sub k,c], the heat capacity effects of the collector, HCE[sub CO], and of the installation, HCE[sub ins], as well as the losses of heat of the pipes to the surroundings, Q[sub 1]. The instantaneous available solar energy, available useful heat, in addition to the wind collector losses to the surroundings, Q[sub u] + W[sub 1], is the difference, in each instant, between the radiation, I[sub g1T], and the radiation threshold, I[sub min].The integration during the day of the instantaneous available solar energy allows us to calculate the daily available function, H[sub T]. The value of H[sub T], measured in the swimming-pool water condensation installation reached 6.92 MJ/(m[sup 2] day ). The calculated values of H[sub T] for a conventional installation condensed by tower water, or air, have been 6.35 and 0.56 MJ/(m[sup 2] day). respectively.

  4. Analysis of the adsorption process and of desiccant cooling systems: a pseudo- steady-state model for coupled heat and mass transfer. [DESSIM, DESSIM2, DESSIM4

    SciTech Connect

    Barlow, R.S.

    1982-12-01

    A computer model to simulate the adiabatic adsorption/desorption process is documented. Developed to predict the performance of desiccant cooling systems, the model has been validated through comparison with experimental data for single-blow adsorption and desorption. A literature review on adsorption analysis, detailed discussions of the adsorption process, and an initial assessment of the potential for performance improvement through advanced component development are included.

  5. Analysis of the adsorption process and of desiccant cooling systems: A pseudo- steady-state model for coupled heat and mass transfer

    NASA Astrophysics Data System (ADS)

    Barlow, R. S.

    1982-12-01

    A computer model to simulate the adiabatic adsorption/desorption process is documented. Developed to predict the performance of desiccant cooling systems, the model has been validated through comparison with experimental data for single-blow adsorption and desorption. A literature review on adsorption analysis, detailed discussions of the adsorption process, and an initial assessment of the potential for performance improvement through advanced component development are included.

  6. Residential solar-heating/cooling system

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Report documents progress of residential solar-heating and cooling system development program at 5-month mark of anticipated 17-month program. System design has been completed, and development and component testing has been initiated. Report includes diagrams, operation overview, optimization studies of subcomponents, and marketing plans for system.

  7. Prototype solar heating and cooling systems

    NASA Technical Reports Server (NTRS)

    1978-01-01

    A collection of monthly status reports on the development of eight prototype solar heating and cooling systems is presented. The effort calls for the development, manufacture, test, system installation, maintenance, problem resolution, and performance evaluation. The systems are 3, 25, and 75 ton size units.

  8. Prototype solar heating and cooling systems

    NASA Technical Reports Server (NTRS)

    1978-01-01

    A collection of monthly status reports are given on the development of eight prototype solar heating and cooling systems. This effort calls for the development, manufacturing, test, system installation, maintenance, problem resolution, and performance evaluation. The systems are 3-, 25-, and 75-ton size units.

  9. Public policy for solar heating and cooling

    NASA Technical Reports Server (NTRS)

    Hirshberg, A. S.

    1976-01-01

    Recent analyses indicated that solar heating and cooling systems for residential buildings are nearly economically competitive with conventional fossil fuel or electric systems, the former having higher initial cost but a lower operating cost than the latter. The paper examines obstacles to the widespread acceptance and use of solar space conditioning systems and explores some general policies which could help to overcome them. The discussion covers such institutional barriers limiting the adoption of solar technologies as existing building codes, financing constraints, and organizational structure of the building industry. The potential impact of financial incentives is analyzed. It is noted that a tax incentive of 25% could speed the use of solar energy by 7 to 8 years and produce an 8% reduction in fossil fuel use by 1990. A preliminary incentive package which could be helpful in promoting solar energy both at federal and state levels is proposed, and the necessary incentive level is analysed.

  10. Advanced desiccant materials research

    NASA Astrophysics Data System (ADS)

    Czanderna, A. W.; Thomas, T. M.

    1986-05-01

    The long-range goal of this task is to understand the role of surface phenomena in desiccant cooling materials. The background information includes a brief introduction to desiccant cooling systems (DCS) and the role of the desiccant as a system component. The purpose, background, rationale, and long-term technical approach for studying advanced desiccant materials are then treated. Experimental methods for measuring water vapor sorption by desiccants are described, and the rationale is then given for choosing a quartz crystal microbalance (QCM) for measuring sorption isotherms, rates, and cyclic stability. Background information is given about the QCM, including the quartz crystal resonator itself, the support structure for the quartz crystal, and the advantages and limitations of a QCM. The apparatus assembled and placed into operation during CY 1985 is described. The functions of the principal components of the equipment, i.e., the QCM, vacuum system, pressure gauges, residual gas analyzer, constant temperature bath, and data acquisition system, are described as they relate to the water vapor sorption measurements now under way. The criteria for narrowing the potential candidates as advanced desiccant materials for the initial studies are given. Also given is a list of 20 principal candidate materials identified based on the criteria and data available in the literature.

  11. Solar-Cooled Hotel in the Virgin Islands

    NASA Technical Reports Server (NTRS)

    Harber, H.

    1982-01-01

    Performance of solar cooling system is described in 21-page report. System provides cooling for public areas including ball rooms, restaurant, lounge, lobby and shops. Chilled water from solar-cooling system is also used to cool hot water from hotel's desalinization plant.

  12. Adiabatic cooling of solar wind electrons

    NASA Technical Reports Server (NTRS)

    Sandbaek, Ornulf; Leer, Egil

    1992-01-01

    In thermally driven winds emanating from regions in the solar corona with base electron densities of n0 not less than 10 exp 8/cu cm, a substantial fraction of the heat conductive flux from the base is transfered into flow energy by the pressure gradient force. The adiabatic cooling of the electrons causes the electron temperature profile to fall off more rapidly than in heat conduction dominated flows. Alfven waves of solar origin, accelerating the basically thermally driven solar wind, lead to an increased mass flux and enhanced adiabatic cooling. The reduction in electron temperature may be significant also in the subsonic region of the flow and lead to a moderate increase of solar wind mass flux with increasing Alfven wave amplitude. In the solar wind model presented here the Alfven wave energy flux per unit mass is larger than that in models where the temperature in the subsonic flow is not reduced by the wave, and consequently the asymptotic flow speed is higher.

  13. Desiccant systems save money

    SciTech Connect

    Kister, P.

    1996-10-01

    Desiccant systems can save the Navy money through lower utility bills. Traditional vapor compression air conditioning systems are required to remove both sensible heat and latent heat (humidity) by cooling the outside air below the dewpoint in order to condense out water vapor. In some cases the air is then required to be reheated to a comfortable level. This requires large amounts of electricity at peak billing rates. Desiccant systems, on the other hand, use a desiccant to remove moisture from the outside air prior to cooling the air using traditional chillers. The desiccant is then reactivated using natural gas heat. This will shift up to 40 percent of the cooling load of the building to natural gas which in many areas of the country is cheaper than electricity, especially during the peak hours in the summer. It also eliminates inefficient reheating and in most cases the temperature of the building can be raised since dry air is more comfortable at higher temperatures than humid air. Many buildings also require special humidity control which is most effectively and efficiently met using a desiccant system. These buildings include hospitals, commissaries, avionics rooms, BOQ`s and BEQ`s, etc.

  14. Market potential for solar heating and cooling in buildings

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The use of solar heating and cooling for buildings as a method of conserving fossil fuels is discussed. The residential and commercial end use consumption of energy is tabulated. A survey to project the energy requirements for home and industry heating and cooling is developed. The survey indicates that there is a market potential for solar heating and cooling of buildings. A prediction of three to five billion dollars per year as the potential for solar heating and cooling is made.

  15. Thermally Activated Desiccant Technology for Heat Recovery and Comfort

    SciTech Connect

    Jalalzadeh, A. A.

    2005-11-01

    Desiccant cooling is an important part of the diverse portfolio of Thermally Activated Technologies (TAT) designed for conversion of heat for the purpose of indoor air quality control. Thermally activated desiccant cooling incorporates a desiccant material that undergoes a cyclic process involving direct dehumidification of moist air and thermal regeneration. Desiccants fall into two categories: liquid and solid desiccants. Regardless of the type, solid or liquid, the governing principles of desiccant dehumidification systems are the same. In the dehumidification process, the vapor pressure of the moist air is higher than that of the desiccant, leading to transfer of moisture from the air to the desiccant material. By heating the desiccant, the vapor pressure differential is reversed in the regeneration process that drives the moisture from the desiccant. Figure 1 illustrates a rotary solid-desiccant dehumidifier. A burner or a thermally compatible source of waste heat can provide the required heat for regeneration.

  16. Low-Flow Liquid Desiccant Air-Conditioning: Demonstrated Performance and Cost Implications

    SciTech Connect

    Kozubal, E.; Herrmann, L.; Deru, M.; Clark, J.; Lowenstein, A.

    2014-09-01

    Cooling loads must be dramatically reduced when designing net-zero energy buildings or other highly efficient facilities. Advances in this area have focused primarily on reducing a building's sensible cooling loads by improving the envelope, integrating properly sized daylighting systems, adding exterior solar shading devices, and reducing internal heat gains. As sensible loads decrease, however, latent loads remain relatively constant, and thus become a greater fraction of the overall cooling requirement in highly efficient building designs, particularly in humid climates. This shift toward latent cooling is a challenge for heating, ventilation, and air-conditioning (HVAC) systems. Traditional systems typically dehumidify by first overcooling air below the dew-point temperature and then reheating it to an appropriate supply temperature, which requires an excessive amount of energy. Another dehumidification strategy incorporates solid desiccant rotors that remove water from air more efficiently; however, these systems are large and increase fan energy consumption due to the increased airside pressure drop of solid desiccant rotors. A third dehumidification strategy involves high flow liquid desiccant systems. These systems require a high maintenance separator to protect the air distribution system from corrosive desiccant droplet carryover and so are more commonly used in industrial applications and rarely in commercial buildings. Both solid desiccant systems and most high-flow liquid desiccant systems (if not internally cooled) add sensible energy which must later be removed to the air stream during dehumidification, through the release of sensible heat during the sorption process.

  17. Solar thermal heating and cooling. A bibliography with abstracts

    NASA Technical Reports Server (NTRS)

    Arenson, M.

    1979-01-01

    This bibliographic series cites and abstracts the literature and technical papers on the heating and cooling of buildings with solar thermal energy. Over 650 citations are arranged in the following categories: space heating and cooling systems; space heating and cooling models; building energy conservation; architectural considerations, thermal load computations; thermal load measurements, domestic hot water, solar and atmospheric radiation, swimming pools; and economics.

  18. Potential of solar cooling systems for peak demand reduction

    SciTech Connect

    Pesaran, A A; Neymark, J

    1994-11-01

    We investigated the technical feasibility of solar cooling for peak demand reduction using a building energy simulation program (DOE2.1D). The system studied was an absorption cooling system with a thermal coefficient of performance of 0.8 driven by a solar collector system with an efficiency of 50% with no thermal storage. The analysis for three different climates showed that, on the day with peak cooling load, about 17% of the peak load could be met satisfactorily with the solar-assisted cooling system without any thermal storage. A performance availability analysis indicated that the solar cooling system should be designed for lower amounts of available solar resources that coincide with the hours during which peak demand reduction is required. The analysis indicated that in dry climates, direct-normal concentrating collectors work well for solar cooling; however, in humid climates, collectors that absorb diffuse radiation work better.

  19. Solar heating and cooling systems design and development

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The development and delivery of eight prototype solar heating and cooling systems for installation and operational test was reported. Two heating and six heating and cooling units will be delivered for single family residences, multiple family residences and commercial applications.

  20. Liquid cooled, linear focus solar cell receiver

    DOEpatents

    Kirpich, Aaron S.

    1985-01-01

    Separate structures for electrical insulation and thermal conduction are established within a liquid cooled, linear focus solar cell receiver for use with parabolic or Fresnel optical concentrators. The receiver includes a V-shaped aluminum extrusion having a pair of outer faces each formed with a channel receiving a string of solar cells in thermal contact with the extrusion. Each cell string is attached to a continuous glass cover secured within the channel with spring clips to isolate the string from the external environment. Repair or replacement of solar cells is effected simply by detaching the spring clips to remove the cover/cell assembly without interrupting circulation of coolant fluid through the receiver. The lower surface of the channel in thermal contact with the cells of the string is anodized to establish a suitable standoff voltage capability between the cells and the extrusion. Primary electrical insulation is provided by a dielectric tape disposed between the coolant tube and extrusion. Adjacent solar cells are soldered to interconnect members designed to accommodate thermal expansion and mismatches. The coolant tube is clamped into the extrusion channel with a releasably attachable clamping strip to facilitate easy removal of the receiver from the coolant circuit.

  1. Liquid cooled, linear focus solar cell receiver

    DOEpatents

    Kirpich, A.S.

    1983-12-08

    Separate structures for electrical insulation and thermal conduction are established within a liquid cooled, linear focus solar cell receiver for use with parabolic or Fresnel optical concentrators. The receiver includes a V-shaped aluminum extrusion having a pair of outer faces each formed with a channel receiving a string of solar cells in thermal contact with the extrusion. Each cell string is attached to a continuous glass cover secured within the channel with spring clips to isolate the string from the external environment. Repair or replacement of solar cells is effected simply by detaching the spring clips to remove the cover/cell assembly without interrupting circulation of coolant fluid through the receiver. The lower surface of the channel in thermal contact with the cells of the string is anodized to establish a suitable standoff voltage capability between the cells and the extrusion. Primary electrical insulation is provided by a dielectric tape disposed between the coolant tube and extrusion. Adjacent solar cells are soldered to interconnect members designed to accommodate thermal expansion and mismatches. The coolant tube is clamped into the extrusion channel with a releasably attachable clamping strip to facilitate easy removal of the receiver from the coolant circuit.

  2. Solar heating and cooling system design and development

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The progress made in the manufacture, test, evaluation, installation, problem resolution, performance evaluation, and development of eight prototype solar heating and combined heating and cooling systems is described.

  3. Prototype solar heating and combined heating and cooling systems

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Eight prototype solar heating and combined heating and cooling systems are being developed. The effort includes development, manufacture, test, installation, maintenance, problem resolution, and performance evaluation.

  4. Prototype solar heating and combined heating and cooling systems

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Eight prototype solar heating and combined heating and cooling systems are considered. This effort includes development, manufacture, test, installation, maintenance, problem resolution, and performance evaluation.

  5. Solar heating and cooling systems design and development

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Solar heating and heating/cooling systems were designed for single family, multifamily, and commercial applications. Subsystems considered included solar collectors, heat storage systems, auxiliary energy sources, working fluids, and supplementary controls, piping, and pumps.

  6. Cooling performance of solar cell-driven, thermoelectric cooling prototype headgear

    SciTech Connect

    Hara, T.; Obora, H.; Sato, S.

    1998-07-01

    Cooling performance of solar cell driven, thermoelectric cooling prototype headgear was examined experimentally. Three types of prototype headgear were made and examined. They were cooled by thermoelectric elements and driven by solar cells. The authors are always able to be cooled anytime and anywhere inside the house in hot season. However, they were not able to be cooled when they worked outside the house. Especially, a personal air-conditioning system is required for the people working outside. Some cooling caps with an electric fan driven by solar cells can be often seen now. However, the fan only blows hot air to the face. They cannot cool down the face below the ambient temperature. The authors tried to cool down the face to the lower temperature below the ambient by a refrigeration system. A thermoelectric element was set at the front of a headgear such as baseball cap or straw hat to cool a forehead. Some pieces of solar cells were mounted on the top and the brim of the headgear to work the thermoelectric element. Hot side of thermoelectric element was cooled by a plate fin an electric fan. The electric fan was also driven by a solar cell. Two types of baseball caps with solar cells and a thermoelectric element and a type of straw hat with them were made and tested. Solar cells were connected to optimize the electric power for the thermoelectric element. An electric fan and its power input were selected to cool maximum the thermoelectric element. Cooling performance and thermal comfort of the headgear were examined by testers in case of sitting, walking and bicycling. The temperature difference between ambient and cooling temperature was required only about 4 degree Celsius. Required power by solar cells was up to about 1.5 watt for a personal cooling.

  7. Prototype solar heating and combined heating and cooling systems

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Schedules and technical progress in the development of eight prototype solar heating and combined solar heating and cooling systems are reported. Particular emphasis is given to the analysis and preliminary design for the cooling subsystem, and the setup and testing of a horizontal thermal energy storage tank configuration and collector shroud evaluation.

  8. Solar heating and cooling system design and development

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The development of eight prototype solar heating and combined heating and cooling systems is reported. Manufacture, test, installation, maintenance, problem resolution, and monitoring the operation of prototype systems is included. Heating and cooling equipment for single family residential and commercial applications and eight operational test sites (four heating and four heating and cooling) is described.

  9. Solar air-conditioning-active, hybrid and passive

    SciTech Connect

    Yellott, J. I.

    1981-04-01

    After a discussion of summer air conditioning requirements in the United States, active, hybrid, and passive cooling systems are defined. Active processes and systems include absorption, Rankine cycle, and a small variety of miscellaneous systems. The hybrid solar cooling and dehumidification technology of desiccation is covered as well as evaporative cooling. The passive solar cooling processes covered include convective, radiative and evaporative cooling. Federal and state involvement in solar cooling is then discussed. (LEW)

  10. Performance Analysis of XCPC Powered Solar Cooling Demonstration Project

    NASA Astrophysics Data System (ADS)

    Widyolar, Bennett K.

    A solar thermal cooling system using novel non-tracking External Compound Parabolic Concentrators (XCPC) has been built at the University of California, Merced and operated for two cooling seasons. Its performance in providing power for space cooling has been analyzed. This solar cooling system is comprised of 53.3 m2 of XCPC trough collectors which are used to power a 23 kW double effect (LiBr) absorption chiller. This is the first system that combines both XCPC and absorption chilling technologies. Performance of the system was measured in both sunny and cloudy conditions, with both clean and dirty collectors. It was found that these collectors are well suited at providing thermal power to drive absorption cooling systems and that both the coinciding of available thermal power with cooling demand and the simplicity of the XCPC collectors compared to other solar thermal collectors makes them a highly attractive candidate for cooling projects.

  11. SERI Desiccant Cooling Test Facility. Status report. Preliminary data on the performance of a rotary parallel-passage silica-gel dehumidifier

    SciTech Connect

    Schultz, K.J.

    1986-04-01

    This report describes the SERI Desiccant Cooling Test Facility. The facility can test bench-scale rotary dehumidifiers over a wide range of controlled conditions. We constructed and installed in the test loop a prototype parallel-passage rotary dehumidifier that has spirally wound polyester tape coated with silica gel. The initial tests gave satisfactory results indicating that approximately 90% of the silica gel was active and the overall Lewis number of the wheel was near unity. The facility has several minor difficulties including an inability to control humidity satisfactorily and nonuniform and highly turbulent inlet velocities. To completely validate the facility requires a range of dehumidifier designs. Several choices are available including constructing a second parallel-passage dehumidifier with the passage spacing more uniform.

  12. Air cooled absorption chillers for solar cooling applications

    NASA Astrophysics Data System (ADS)

    Biermann, W. J.; Reimann, R. C.

    1982-03-01

    The chemical composition of a 'best' absorption refrigerant system is identified, and those properties of the system necessary to design hot water operated, air cooled chilling equipment are determined. Air cooled chillers from single family residential sizes into the commercial rooftop size range are designed and operated.

  13. Solar powered dehumidifier apparatus

    DOEpatents

    Jebens, Robert W.

    1980-12-30

    A thermally insulated light transmitting housing forms a chamber containing a desiccant and having a first gas port open to the ambient and a second gas port connected by a two way valve to a volume to be dried. Solar energy transmitted through the housing heats and dries the desiccant. The increased air pressure due to the heating of the volume to be dried causes the air from the volume to be expelled through the valve into the chamber. The desiccant is then cooled by shielding it from solar energy before the volume cools thereby increasing its moisture absorbing capacity. Then the volume is allowed to cool drawing dehumidified air through the desiccant and the valve into the volume to be dried. This cycle is then repeated.

  14. Performance of active solar space-cooling systems: The 1980 cooling season

    NASA Astrophysics Data System (ADS)

    Blum, D.; Frock, S.; Logee, T.; Missal, D.; Wetzel, P.

    1980-12-01

    Solar cooling by an absorption chiller is not a cost effective method to use solar heat. This statement is substantiated by careful analysis of each subsystem and equipment component. Good designs and operating procedures are identified. The problems which reduce cost effectiveness are pointed out. There are specific suggestions for improvements. Finally, there is a comparison of solar cooling by absorption chilling and using photovoltaic cells.

  15. Preliminary design package for solar heating and cooling systems

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Summarized preliminary design information on activities associated with the development, delivery and support of solar heating and cooling systems is given. These systems are for single family dwellings and commercial applications. The heating/cooling system use a reversible vapor compression heat pump that is driven in the cooling mode by a Rankine power loop, and in the heating mode by a variable speed electric motor. The heating/cooling systems differ from the heating-only systems in the arrangement of the heat pump subsystem and the addition of a cooling tower to provide the heat sink for cooling mode operation.

  16. Water cooled absorption chillers for solar cooling applications

    NASA Astrophysics Data System (ADS)

    Biermann, W. J.; Reimann, R. C.

    1982-03-01

    A broad line of absorption chillers designed to operate with hot fluids at as low a temperature as practical while rejecting heat to a stream of water was developed. A packaging concept for solar application in which controls, pumps, valves and other system components could be factor assembled into a unitary solar module was investigated.

  17. Solar heating and cooling diode module

    DOEpatents

    Maloney, Timothy J.

    1986-01-01

    A high efficiency solar heating system comprising a plurality of hollow modular units each for receiving a thermal storage mass, the units being arranged in stacked relation in the exterior frame of a building, each of the units including a port for filling the unit with the mass, a collector region and a storage region, each region having inner and outer walls, the outer wall of the collector region being oriented for exposure to sunlight for heating the thermal storage mass; the storage region having an opening therein and the collector region having a corresponding opening, the openings being joined for communicating the thermal storage mass between the storage and collector regions by thermosiphoning; the collector region being disposed substantially below and in parallel relation to the storage region in the modular unit; and the inner wall of the collector region of each successive modular unit in the stacked relation extending over the outer wall of the storage region of the next lower modular unit in the stacked relation for reducing heat loss from the system. Various modifications and alternatives are disclosed for both heating and cooling applications.

  18. Composite desiccant structure

    DOEpatents

    Fraioli, Anthony V.; Schertz, William W.

    1987-01-01

    A composite formed of small desiccant particles retained in a dark matrix composed of a porous binder containing a transition metal oxide with pores to provide moisture transport with respect to the particles, and metallic fibers to remove the heat of condensation during dehumidification and provide heat for the removal of moisture during regeneration. The moisture absorbing properties of the composite may be regenerated by exposure of the dark matrix to solar radiation with dehumidification occurring at night.

  19. Composite desiccant structure

    DOEpatents

    Fraioli, A.V.; Schertz, W.W.

    1984-06-06

    This patent discloses a composite formed of small desiccant particles retained in a dark matrix composed of a porous binder containing a transition metal oxide with pores to provide moisture transport with respect to the particles, and metallic fibers to remove the heat of condensation during dehumidification and provide heat for the removal of moisture during regeneration. The moisture absorbing properties of the composite may be regenerated by exposure of the dark matrix to solar radiation with dehumidification occurring at night.

  20. Evaluation of thermal-storage concepts for solar cooling applications

    NASA Astrophysics Data System (ADS)

    Hughes, P. J.; Morehouse, J. H.; Choi, M. K.; White, N. M.; Scholten, W. B.

    1981-10-01

    Various configuration concepts for utilizing thermal energy storage to improve the thermal and economic performance of solar cooling systems for buildings were analyzed. The storge concepts evaluated provide short-term thermal storge via the bulk containment of water or salt hydrates. The evaluations were made for both residential-size cooling systems (3-ton) and small commercial-size cooling systems (25-ton). The residential analysis considers energy requirements for space heating, space cooling and water heating, while the commercial building analysis is based only on energy requirements for space cooling. The commercial building analysis considered a total of 10 different thermal storage/solar systems, 5 each for absorption and Rankine chiller concepts. The residential analysis considered 4 thermal storage/solar systems, all utilizing an absorption chiller. The trade-offs considered include: cold-side versus hot-side storage, single vs multiple stage storage, and phase-change vs sensible heat storage.

  1. POTENTIAL ENVIRONMENTAL IMPACTS OF SOLAR HEATING AND COOLING SYSTEMS

    EPA Science Inventory

    This report discusses potential environmental consequences of solar energy utilization for heating and cooling buildings. It identifies the areas in which both positive and negative impacts are possible, summarizes the national research and development program directed toward sol...

  2. Prototype solar heating and combined heating cooling systems

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The design and development of eight prototype solar heating and combined heating and cooling systems is discussed. The program management and systems engineering are reported, and operational test sites are identified.

  3. Solar heating and cooling systems design and development

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Progress in the development of prototype solar heating/cooling systems is reported. Results obtained from refinement/improvement of the single family, multifamily, and commercial systems configurations and generalized studies on several of the subsystems are presented.

  4. Solar heating and cooling technical data and systems analysis

    NASA Technical Reports Server (NTRS)

    Christensen, D. L.

    1977-01-01

    The research activities described herein were concentrated on the areas of economics, heating and cooling systems, architectural design, materials characteristics, climatic conditions, educational information packages, and evaluation of solar energy systems and components.

  5. Preliminary design activities for solar heating and cooling systems

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Information on the development of solar heating and cooling systems is presented. The major emphasis is placed on program organization, system size definition, site identification, system approaches, heat pump and equipment design, collector procurement, and other preliminary design activities.

  6. Solar residential heating and cooling system development test program

    NASA Technical Reports Server (NTRS)

    Humphries, W. R.; Melton, D. E.

    1974-01-01

    A solar heating and cooling system is described, which was installed in a simulated home at Marshall Space Flight Center. Performance data are provided for the checkout and initial operational phase for key subsystems and for the total system. Valuable information was obtained with regard to operation of a solar cooling system during the first summer of operation. Areas where improvements and modifications are required to optimize such a system are discussed.

  7. Solar heating and cooling systems design and development. [prototype development

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The development of twelve prototype solar heating/cooling systems, six heating and six heating and cooling systems, two each for single family, multi-family, and commercial applications, is reported. Schedules and technical discussions, along with illustrations on the progress made from April 1, 1977 through June 30, 1977 are detailed.

  8. Passive cooling with solar updraft and evaporative downdraft chimneys

    SciTech Connect

    Mignon, G.V.; Cunningham, W.A.; Thompson, T.L.

    1985-01-01

    Computer models have been developed to describe the operation of both solar updraft and evaporative downdraft chimneys. Design studies are being conducted at the present time to use the towers for cooling an experimental, well instrumented, structure to study passive cooling in residential buildings. (MHR)

  9. Passive thermosyphon solar heating and cooling module with supplementary heating

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A collection of three quarterly reports from Sigma Research, Inc., covering progress and status from January through September 1977 are presented. Three heat exchangers are developed for use in a solar heating and cooling system for installation into single-family dwellings. Each exchanger consists of one heating and cooling module and one submerged electric water heating element.

  10. Performance and operational analysis of a liquid desiccant open-flow solar collector

    NASA Astrophysics Data System (ADS)

    Grodzka, P. G.; Rico, S. S.

    1982-10-01

    Theoretical predictions of the heat and mass transfer in an open flow solar collector used in conjunction with an absorption chiller are compared with performance data from a rooftop system. The study focuses on aqueous solutions of a hygroscopic salt, e.g., LiCl, flowing continuously over a solar absorbing surface. Water in the solution sublimes to a region of lower vapor pressure, i.e., the atmosphere. Direction of the water-depleted dessiccant to a storage volume and then to circulation around an evaporator unit permits operation of a solar-powered air conditioner. A closed form solution was defined for the heat and mass transfer, along with a finite difference solution. The system studied comprised a sloped roof top with 2500 sq ft of asphalt shingles, collector pipes beneath the shingles, and two 500 gal storage tanks. Relatively good agreement was found between the models and the recorded data, although some discrepancies were present when considering temperatures and performance at specific times of day. The measured 30-40% efficiencies indicated that further development of the system is warranted.

  11. Convective Array Cooling for a Solar Powered Aircraft

    NASA Technical Reports Server (NTRS)

    Colozza, Anthony J.; Dolce, James (Technical Monitor)

    2003-01-01

    A general characteristic of photovoltaics is that they increase in efficiency as their operating temperature decreases. Based on this principal, the ability to increase a solar aircraft's performance by cooling the solar cells was examined. The solar cells were cooled by channeling some air underneath the cells and providing a convective cooling path to the back side of the array. A full energy balance and flow analysis of the air within the cooling passage was performed. The analysis was first performed on a preliminary level to estimate the benefits of the cooling passage. This analysis established a clear benefit to the cooling passage. Based on these results a more detailed analysis was performed. From this cell temperatures were calculated and array output power throughout a day period were determined with and without the cooling passage. The results showed that if the flow through the cooling passage remained laminar then the benefit in increased output power more than offset the drag induced by the cooling passage.

  12. Solar heating and cooling system design and development

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The design and development of marketable solar heating and cooling systems for single family and commercial applications is described. The delivery, installation, and monitoring of the prototype systems are discussed. Seven operational test sites are discussed in terms of system performance. Problems encountered with equipment and installation were usually due to lack of skills required for solar system installation.

  13. Inhibitor analysis for a solar heating and cooling system

    NASA Technical Reports Server (NTRS)

    Tabony, J. H.

    1977-01-01

    A study of potential corrosion inhibitors for the NASA solar heating and cooling system which uses aluminum solar panels is provided. Research consisted of testing using a dynamic corrosion system, along with an economic analysis of proposed corrosion inhibitors. Very good progress was made in finding a suitable inhibitor for the system.

  14. Problems encountered in solar heating and cooling systems

    NASA Technical Reports Server (NTRS)

    Cash, M.

    1979-01-01

    Report discussing various experiences of workers at Marshall Space Flight Center in developing solar heating and cooling systems is presented. Presents compilation of problems and their resolutions which can assist designers of solar-energy systems and prevent repetition of errors.

  15. Prototype solar heating and cooling systems including potable hot water

    NASA Technical Reports Server (NTRS)

    1978-01-01

    These combined quarterly reports summarize the activities from November 1977 through September 1978, and over the progress made in the development, delivery and support of two prototype solar heating and cooling systems including potable hot water. The system consists of the following subsystems: solar collector, auxiliary heating, potable hot water, storage, control, transport, and government-furnished site data acquisition.

  16. Preliminary design package for prototype solar heating and cooling systems

    NASA Technical Reports Server (NTRS)

    1978-01-01

    A summary is given of the preliminary analysis and design activity on solar heating and cooling systems. The analysis was made without site specific data other than weather; therefore, the results indicate performance expected under these special conditions. Major items include a market analysis, design approaches, trade studies and other special data required to evaluate the preliminary analysis and design. The program calls for the development and delivery of eight prototype solar heating and cooling systems for installation and operational test. Two heating and six heating and cooling units will be delivered for Single Family Residences, Multiple-family Residences and commercial applications.

  17. Solar cooling system performance, Frenchman's Reef Hotel, Virgin Islands

    NASA Technical Reports Server (NTRS)

    Harber, H.

    1981-01-01

    The operational and thermal performance of a variety of solar systems are described. The Solar Cooling System was installed in a hotel at St. Thomas, U. S. Virgin Islands. The system consists of the evacuated glass tube collectors, two 2500 gallon tanks, pumps, computerized controller, a large solar optimized industrial sized lithium bromide absorption chiller, and associated plumbing. Solar heated water is pumped through the system to the designed public areas such as lobby, lounges, restaurant and hallways. Auxiliary heat is provided by steam and a heat exchanger to supplement the solar heat.

  18. Solar cooling system performance, Frenchman's Reef Hotel, Virgin Islands

    NASA Astrophysics Data System (ADS)

    Harber, H.

    1981-09-01

    The operational and thermal performance of a variety of solar systems are described. The Solar Cooling System was installed in a hotel at St. Thomas, U. S. Virgin Islands. The system consists of the evacuated glass tube collectors, two 2500 gallon tanks, pumps, computerized controller, a large solar optimized industrial sized lithium bromide absorption chiller, and associated plumbing. Solar heated water is pumped through the system to the designed public areas such as lobby, lounges, restaurant and hallways. Auxiliary heat is provided by steam and a heat exchanger to supplement the solar heat.

  19. Solar heating and cooling technical data and systems analysis

    NASA Technical Reports Server (NTRS)

    Christensen, D. L.

    1976-01-01

    The accomplishments of a project to study solar heating and air conditioning are outlined. Presentation materials (data packages, slides, charts, and visual aids) were developed. Bibliographies and source materials on materials and coatings, solar water heaters, systems analysis computer models, solar collectors and solar projects were developed. Detailed MIRADS computer formats for primary data parameters were developed and updated. The following data were included: climatic, architectural, topography, heating and cooling equipment, thermal loads, and economics. Data sources in each of these areas were identified as well as solar radiation data stations and instruments.

  20. An approach for cooling by solar energy

    NASA Astrophysics Data System (ADS)

    Rabeih, S. M.; Wahhab, M. A.; Asfour, H. M.

    The present investigation is concerned with the possibility to base the operation of a household refrigerator on solar energy instead of gas fuel. The currently employed heating system is to be replaced by a solar collector with an absorption area of two sq m. Attention is given to the required changes in the generator design, the solar parameters at the location of refrigerator installation, the mathematical approach for the thermal analysis of the solar collector, the development of a computer program for the evaluation of the important parameters, the experimental test rig, and the measurement of the experimental parameters. A description is given of the obtained optimum operating conditions for the considered system.

  1. Solar Induced Climate Changes and Cooling of the Earth

    NASA Astrophysics Data System (ADS)

    Yousef, Shahinaz M.

    2011-06-01

    Evidences are given for the cooling effect induced by solar weak cycles. It is forecasted that the coming solar cycle number 24, which has started on January 2008, would be very weak. This cycle would be followed by several weak cycles. Its very start on January 2008 have induced a climate change that forced global cooling, Indeed all global temperature monitors have shown temperature drops. The GISS monitor showed a 0.75°C drop between January 2007 and January 2008. This sharp temperature drop characterizes cooling induced by weak cycles as was evident by historical temperature records. It also happened in the right exact timing of the start of cycle 24. This cooling is real and could last for some time. The cooling well width is location dependant. Last January cooling left many countries in deep freeze. Cooling is very serious and can destroy crops and cause famines. This cooling is instrumentally recorded. This is an appeal to scientists to consider the present cooling seriously, after all the truth ought to be followed. Alert is also given to the reaponsible authorities to work promptly to choose the proper crops that can tolerate the cold otherwise it would be a disaster worldwide.

  2. Solar-heating and cooling demonstration project

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Florida Solar Energy Center has retrofitted office building, approximately 5,000 square feet of area, with solar heating and air-conditioning. Information on operation, installation, controls, and hardware for system is contained in 164 page report. Document includes manufacturer's product literature and detailed drawings.

  3. Solar heating and cooling system installed at Leavenworth, Kansas

    NASA Technical Reports Server (NTRS)

    1980-01-01

    A solar heating and cooling is described which is designed to furnish 90 percent of the overall heating load, 70 percent of the cooling load and 100 percent of the domestic hot water load. The building has two floors with a total of 12,000 square feet gross area. The system has 120 flat-plate liquid solar panels with a net area of 2,200 square feet. Five 3 ton Arkla solar assisted absorption units provide the cooling, in conjunction with a 3,000 gallon chilled water storage tank. Two 3,000 gallon storage tanks are provided with one designated for summer use, whereas both tanks are utilized during winter.

  4. Solar heating and cooling system installed at Leavenworth, Kansas

    NASA Astrophysics Data System (ADS)

    1980-06-01

    A solar heating and cooling is described which is designed to furnish 90 percent of the overall heating load, 70 percent of the cooling load and 100 percent of the domestic hot water load. The building has two floors with a total of 12,000 square feet gross area. The system has 120 flat-plate liquid solar panels with a net area of 2,200 square feet. Five 3 ton Arkla solar assisted absorption units provide the cooling, in conjunction with a 3,000 gallon chilled water storage tank. Two 3,000 gallon storage tanks are provided with one designated for summer use, whereas both tanks are utilized during winter.

  5. Application of solar ponds to district heating and cooling

    NASA Astrophysics Data System (ADS)

    Leboeuf, C. M.

    1981-04-01

    A preliminary investigation is reported of the feasibility of incorporating solar ponds into subdivisions to provide district heating, domestic hot water (DHW), and district cooling. Two locations were chosen for analysis: Fort Worth, Texas and Washington, D.C. Solar ponds were sized to meet space heating, cooling, and DHW loads in each location for differing community sizes. Parameters such as storage layer temperature, pond geometry, and storage depth vs surface area were varied to determine the most effective approach to solar pond utilization. A distribution system for the district heating system was designed, including sizing of heat exchangers, piping, and pumps. Cost estimates for the pond and distribution system were formulated by using data generated in pond sizing, as well as associated system costs (e.g., salt costs and distribution system costs). Finally, solar ponds were found to be competitive with residential flat plate collector systems, with delivered energy costs as low as $16.00/GJ.

  6. Solar heating and cooling technical data and systems analysis

    NASA Technical Reports Server (NTRS)

    Christensen, D. L.

    1976-01-01

    The acquisition and processing of selected parametric data for inclusion in a computerized Data Base using the Marshall Information Retrieval and Data System (MIRADS) developed by NASA-MSFC is discussed. This data base provides extensive technical and socioeconomic information related to solar energy heating and cooling on a national scale. A broadly based research approach was used to assist in the support of program management and the application of a cost-effective program for solar energy development and demonstration.

  7. On carbon monoxide cooling in the solar atmosphere

    NASA Technical Reports Server (NTRS)

    Mauas, Pablo J.; Avrett, Eugene H.; Loeser, Rudolf

    1990-01-01

    The CO cooling rate for models of the solar atmosphere using the detailed line-by-line CO opacity in the fundamental band, and carrying out a full radiative transfer calculation for each line is computed. The importance of the different assumptions that have been made to obtain the CO cooling rate and find that when detailed optical depth effects are taken into account, the calculated CO cooling rate at line optical depths near unity can be smaller than optically thin estimates by more than an order of magnitude is studied. It is found that CO cooling does not account for the missing source of radiative cooling in the temperature minimum region of the quiet sun.

  8. Keeping Cool With Solar-Powered Refrigeration

    NASA Technical Reports Server (NTRS)

    2003-01-01

    In the midst of developing battery-free, solar-powered refrigeration and air conditioning systems for habitats in space, David Bergeron, the team leader for NASA's Advanced Refrigerator Technology Team at Johnson Space Center, acknowledged the need for a comparable solar refrigerator that could operate in conjunction with the simple lighting systems already in place on Earth. Bergeron, a 20-year veteran in the aerospace industry, founded the company Solus Refrigeration, Inc., in 1999 to take the patented advanced refrigeration technology he co-developed with his teammate, Johnson engineer Michael Ewert, to commercial markets. Now known as SunDanzer Refrigeration, Inc., Bergeron's company is producing battery-free, photovoltaic (PV) refrigeration systems under license to NASA, and selling them globally.

  9. Solar--heated and cooled office building--Dalton, Georgia

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Modern energy efficient building is heated and cooled by five rows of flat plate solar collectors; its domestic hot water needs are also met. Final report includes detailed drawings and photographs, manufacturer's literature, performance specifications, acceptance test data, and performance verification statements. Operation and maintenance manual is also attached.

  10. Solar Heating and Cooling of Residential Buildings: Design of Systems.

    ERIC Educational Resources Information Center

    Colorado State Univ., Ft. Collins. Solar Energy Applications Lab.

    This is the second of two training courses designed to develop the capability of practitioners in the home building industry to design solar heating and cooling systems. The course is organized in 23 modules to separate selected topics and to facilitate learning. Although a compact schedule of one week is shown, a variety of formats can be…

  11. Prototype solar heating and cooling systems including potable hot water

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Progress is reviewed in the development, delivery, and support of two prototype solar heating and cooling systems including potable hot water. The system consisted of the following subsystems: collector, auxiliary heating, potable hot water, storage, control, transport, and government-furnished site data acquisition.

  12. Corrosion inhibitors for solar-heating and cooling

    NASA Technical Reports Server (NTRS)

    Humphries, T. S.

    1979-01-01

    Report describes results of tests conducted to evaluate abilities of 12 candidate corrosion inhibitors to protect aluminum, steel, copper, or stainless steel at typical conditions encountered in solar heating and cooling systems. Inhibitors are based on sodium salts including nitrates, borates, silicates, and phosphates.

  13. Solar-Heated and Cooled Office Building--Columbus, Ohio

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Final report documents solar-energy system installed in office building to provide space heating, space cooling and domestic hot water. Collectors mounted on roof track Sun and concentrate rays on fluid-circulating tubes. Collected energy is distributed to hot-water-fired absorption chiller and space-heating and domestic-hot-water preheating systems.

  14. The development of a solar residential heating and cooling system

    NASA Technical Reports Server (NTRS)

    1975-01-01

    The MSFC solar heating and cooling facility was assembled to demonstrate the engineering feasibility of utilizing solar energy for heating and cooling buildings, to provide an engineering evaluation of the total system and the key subsystems, and to investigate areas of possible improvement in design and efficiency. The basic solar heating and cooling system utilizes a flat plate solar energy collector, a large water tank for thermal energy storage, heat exchangers for space heating, and an absorption cycle air conditioner for space cooling. A complete description of all systems is given. Development activities for this test system included assembly, checkout, operation, modification, and data analysis, all of which are discussed. Selected data analyses for the first 15 weeks of testing are included, findings associated with energy storage and the energy storage system are outlined, and conclusions resulting from test findings are provided. An evaluation of the data for summer operation indicates that the current system is capable of supplying an average of 50 percent of the thermal energy required to drive the air conditioner. Preliminary evaluation of data collected for operation in the heating mode during the winter indicates that nearly 100 percent of the thermal energy required for heating can be supplied by the system.

  15. International Energy Agency Solar Heating and Cooling Program

    NASA Astrophysics Data System (ADS)

    Brooks, A. J.

    This trip was undertaken to participate in and represent the United States Industry at the International Energy Agency (IEA) Solar Heating and Cooling Program (SHCP) Task 14 Workshop. The meeting took place at the A1 Bani Hotel in Rome Italy.

  16. Active solar heating and cooling information user study

    SciTech Connect

    Belew, W.W.; Wood, B.L.; Marle, T.L.; Reinhardt, C.L.

    1981-01-01

    The results of a series of telephone interviews with groups of users of information on active solar heating and cooling (SHAC). An earlier study identified the information user groups in the solar community and the priority (to accelerate solar energy commercialization) of getting information to each group. In the current study only high-priority groups were examined. Results from 19 SHAC groups respondents are analyzed in this report: DOE-Funded Researchers, Non-DOE-Funded Researchers, Representatives of Manufacturers (4 groups), Distributors, Installers, Architects, Builders, Planners, Engineers (2 groups), Representatives of Utilities, Educators, Cooperative Extension Service County Agents, Building Owners/Managers, and Homeowners (2 groups). The data will be used as input to the determination of information products and services the Solar Energy Research Institute, the Solar Energy Information Data Bank Network, and the entire information outreach community should be preparing and disseminating.

  17. Solar-powered Rankine heat pump for heating and cooling

    NASA Technical Reports Server (NTRS)

    Rousseau, J.

    1978-01-01

    The design, operation and performance of a familyy of solar heating and cooling systems are discussed. The systems feature a reversible heat pump operating with R-11 as the working fluid and using a motor-driven centrifugal compressor. In the cooling mode, solar energy provides the heat source for a Rankine power loop. The system is operational with heat source temperatures ranging from 155 to 220 F; the estimated coefficient of performance is 0.7. In the heating mode, the vapor-cycle heat pump processes solar energy collected at low temperatures (40 to 80 F). The speed of the compressor can be adjusted so that the heat pump capacity matches the load, allowing a seasonal coefficient of performance of about 8 to be attained.

  18. Overview-absorption/Rankine solar cooling program

    NASA Astrophysics Data System (ADS)

    Wahlig, M.; Heitz, A.; Boyce, B.

    1980-03-01

    The tasks being performed in the absorption and Rankine program areas run the gamut from basic work on fluids to development of chillers and chiller components, to field and reliability testing of complete cooling systems. In the absorption program, there are six current and five essentially completed projects. In the Rankine program, there are five current projects directly supported by DOE, and three projects funded through and managed by NASA/MSFC (Manned Space Flight Center, Huntsville, Alabama). The basic features of these projects are discussed. The systems under development in five of these current projects were selected for field testing in the SOLERAS program, a joint US-Saudi Arabian enterprise. Some technical highlights of the program are presented.

  19. Evaluation of hybrid solar/fossil Rankine-cooling concept

    SciTech Connect

    Curran, H M

    1980-11-01

    The hybrid solar/fossil Rankine cycle is analyzed thermodynamically to determine fuel use and efficiency. The hybrid system is briefly compared with solar organic Rankine systems with a fossil fuel auxiliary mode, and with geothermal resources. The economic evaluation compares the present value of the superheater fuel cost over the system lifetime with the first cost reduction obtained by substituting a hybrid solar/fossil Rankine engine for an organic Rankine engine. The economics analysis indicates that even if the hybrid solar/fossil Rankine cooling system were developed to the point of being a commercial product with an economic advantage over an otherwise equivalent solar organic Rankine cooling system, it would gradually lose that advantage with rising fuel costs and decreasing collector costs. From the standpoint of national fossil fuel conservation, the hybrid concept would be preferable only in applications where the operating duration in the solar/fossil mode would be substantially greater than in the fossil fuel-only auxiliary mode. (LEW)

  20. Solar heating and cooling demonstration project at the Florida solar energy center

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The retrofitted solar heating and cooling system installed at the Florida Solar Energy Center is described. The system was designed to supply approximately 70 percent of the annual cooling and 100 percent of the heating load. The project provides unique high temperature, nonimaging, nontracking, evacuated tube collectors. The design of the system was kept simple and employs five hydronic loops. They are energy collection, chilled water production, space cooling, space heating and energy rejection. Information is provided on the system's acceptance test results operation, controls, hardware and installation, including detailed drawings.

  1. Solar heating and cooling system design and development

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The progress of the program during the sixth program quarter is reported. The program calls for the development and delivery of eight prototype solar heating and cooling systems for installation and operational test. The William O'Brien single-family heating system was installed and is operational. The New Castle single-family heating residence is under construction. The Kansas University (KU) system is in the final design stages. The 25 ton cooling subsystem for KU is the debugging stage. Pressure drops that were greater than anticipated were encountered. The 3 ton simulation work is being finalized and the design parameters for the Rankine system were determined from simulation output.

  2. "Self-packaging" desiccant

    NASA Technical Reports Server (NTRS)

    Fedors, R. F.

    1979-01-01

    Desiccant, consisting of water-soluble filler contained in water-permeable elastomeric matrix, absorbs large quantities of water without becoming sticky or releasing corrosive agents. Desiccant may be molded into virtually any shape depending on area of application.

  3. Solar heating and cooling system installed at Columbus, Ohio

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The Solar Energy System was installed as a part of a new construction of a college building. The building will house classrooms and laboratories, administrative offices and three lecture halls. The Solar Energy System consists of 4,096 square feet (128 panels) Owens/Illinois Evacuated Glass Tube Collector Subsystem, and a 5,000 gallon steel tank below ground storage system. Hot water is circulated between the collectors and storage tank, passing through a water/lithium bromide absorption chiller to cool the building.

  4. Solar heating and cooling system installed at Columbus, Ohio

    NASA Astrophysics Data System (ADS)

    1980-09-01

    The Solar Energy System was installed as a part of a new construction of a college building. The building will house classrooms and laboratories, administrative offices and three lecture halls. The Solar Energy System consists of 4,096 square feet (128 panels) Owens/Illinois Evacuated Glass Tube Collector Subsystem, and a 5,000 gallon steel tank below ground storage system. Hot water is circulated between the collectors and storage tank, passing through a water/lithium bromide absorption chiller to cool the building.

  5. Solar Cooling for Buildings. Workshop Proceedings (Los Angeles, California, February 6-8, 1974).

    ERIC Educational Resources Information Center

    de Winter, Francis, Ed.

    A consensus has developed among U.S. solar researchers that the solar-powered cooling of buildings is an important topic. Most solar heating systems are technically simpler, and more highly developed, than solar cooling devices are. The determination of the best design concept for any particular application is not a simple process. Significant…

  6. Corrosion inhibitors for solar heating and cooling systems

    NASA Technical Reports Server (NTRS)

    Humphries, T. S.; Deramus, G. E., Jr.

    1977-01-01

    Problems dealing with corrosion and corrosion protection of solar heating and cooling systems are discussed. A test program was conducted to find suitable and effective corrosion inhibitors for systems employing either water or antifreeze solutions for heat transfer and storage. Aluminum-mild-steel-copper-stainless steel assemblies in electrical contact were used to simulate a multimetallic system which is the type most likely to be employed. Several inhibitors show promise for this application.

  7. Modern solar maximum forced late twentieth century Greenland cooling

    NASA Astrophysics Data System (ADS)

    Kobashi, T.; Box, J. E.; Vinther, B. M.; Goto-Azuma, K.; Blunier, T.; White, J. W. C.; Nakaegawa, T.; Andresen, C. S.

    2015-07-01

    The abrupt Northern Hemispheric warming at the end of the twentieth century has been attributed to an enhanced greenhouse effect. Yet Greenland and surrounding subpolar North Atlantic remained anomalously cold in 1970s to early 1990s. Here we reconstructed robust Greenland temperature records (North Greenland Ice Core Project and Greenland Ice Sheet Project 2) over the past 2100 years using argon and nitrogen isotopes in air trapped within ice cores and show that this cold anomaly was part of a recursive pattern of antiphase Greenland temperature responses to solar variability with a possible multidecadal lag. We hypothesize that high solar activity during the modern solar maximum (approximately 1950s-1980s) resulted in a cooling over Greenland and surrounding subpolar North Atlantic through the slowdown of Atlantic Meridional Overturning Circulation with atmospheric feedback processes.

  8. Solar heating and cooling demonstration project at the Florida Solar Energy Center

    SciTech Connect

    Hankins, J.D.

    1980-02-01

    The retrofitted solar heating and cooling system installed at the Florida Solar Energy Center is described. Information is provided on the system's test, operation, controls, hardware and installation, including detailed drawings. The Center's office building, approximately 5000 square feet of space, with solar air conditioning and heating as a demonstration of the technical feasibility is located just north of Port Canaveral, Florida. The system was designed to supply approximately 70% of the annual cooling and 100% of the heating load. The project provides unique high-temperature, non-imaging, non-tracking, evacuated-tube collectors. The design of the system was kept simple and employs five hydronic loops. They are energy collection, chilled water production, space cooling, space heating and energy rejection.

  9. Double-sided solar-cell package

    NASA Technical Reports Server (NTRS)

    Shelpuk, B.

    1978-01-01

    Cost-effective solar-cell package is proposed for development of practical solar-cell system. Since cells are enclosed in inexpensive plastic tubes, forced-air-cooling loop is proposed to maintain cell temperature at adequate levels. Loop must include desiccant to remove moisture from hermetic enclosures to prevent cell corrosion.

  10. Citywide Impacts of Cool Roof and Rooftop Solar Photovoltaic Deployment on Near-Surface Air Temperature and Cooling Energy Demand

    NASA Astrophysics Data System (ADS)

    Salamanca, F.; Georgescu, M.; Mahalov, A.; Moustaoui, M.; Martilli, A.

    2016-04-01

    Assessment of mitigation strategies that combat global warming, urban heat islands (UHIs), and urban energy demand can be crucial for urban planners and energy providers, especially for hot, semi-arid urban environments where summertime cooling demands are excessive. Within this context, summertime regional impacts of cool roof and rooftop solar photovoltaic deployment on near-surface air temperature and cooling energy demand are examined for the two major USA cities of Arizona: Phoenix and Tucson. A detailed physics-based parametrization of solar photovoltaic panels is developed and implemented in a multilayer building energy model that is fully coupled to the Weather Research and Forecasting mesoscale numerical model. We conduct a suite of sensitivity experiments (with different coverage rates of cool roof and rooftop solar photovoltaic deployment) for a 10-day clear-sky extreme heat period over the Phoenix and Tucson metropolitan areas at high spatial resolution (1-km horizontal grid spacing). Results show that deployment of cool roofs and rooftop solar photovoltaic panels reduce near-surface air temperature across the diurnal cycle and decrease daily citywide cooling energy demand. During the day, cool roofs are more effective at cooling than rooftop solar photovoltaic systems, but during the night, solar panels are more efficient at reducing the UHI effect. For the maximum coverage rate deployment, cool roofs reduced daily citywide cooling energy demand by 13-14 %, while rooftop solar photovoltaic panels by 8-11 % (without considering the additional savings derived from their electricity production). The results presented here demonstrate that deployment of both roofing technologies have multiple benefits for the urban environment, while solar photovoltaic panels add additional value because they reduce the dependence on fossil fuel consumption for electricity generation.

  11. Solar heating and cooling of residential buildings: sizing, installation and operation of systems. 1980 edition

    SciTech Connect

    1980-09-01

    This manual was prepared as a text for a training course on solar heating and cooling of residential buildings. The course and text are directed toward sizing, installation, operation, and maintenance of solar systems for space heating and hot water supply, and solar cooling is treated only briefly. (MHR)

  12. The development and cooling of a solar limb-flare

    NASA Technical Reports Server (NTRS)

    Veck, N. J.; Strong, K. T.; Jordan, C.; Simnett, G. M.; Cargill, P. J.; Priest, E. R.

    1984-01-01

    Observations of a flare that began in soft X-rays at 20:37 UT on April 12, 1980 at the west limb of the sun are discussed. The observations of the flare and postflare loops are first described, and the Solar Maximum Mission data are interpreted in terms of the temperature, density, and geometry of the emitting regions. The observed postflare cooling time is compared with that expected from radiation, conduction, and enthalpy flux. The loop model is discussed, and the observed events are compared with other proposed models.

  13. Quantum-radiative cooling for solar cells with textured surface

    NASA Astrophysics Data System (ADS)

    Gilman, Boris; Ivanov, Igor

    2004-11-01

    Efficient technique of Quantum Radiative Cooling (QRC) of textured Solar Cells and Modules is described that is capable of Solar Module (SM) temperature reduction by 5-20C, resulting in 3-10% efficiency increase. Novel methods are based on the quantum assisted IR emission from the surface covered by either multi-layer coatings made of Si-nitride, SiO or Si oxy-nitride films or specifically designed insulating sun-transparent chamber (QRC zone) that contains Selective Emissive (SE) gas or gas mix. QRC zone is mounted on the top of Solar Module replacing existing lamination coatings. To enhance the efficiency of QRC some specific methods and fabrication procedures are proposed to form an electricly charged textured surface that provide a high Electric Field at the surface thus enhancing IR emissivity from the surface. Such procedure can be also used to form the field Induced Surface Barriers in the Si-based Solar Cells that can substitute the existing diffused Emitters resulting in significant reduction of the Cycle Time as well as prospective Fabrication Cost.

  14. Site-dependent factors affecting the economic feasibility of solar powered absorption cooling

    NASA Technical Reports Server (NTRS)

    Bartlett, J. C.

    1977-01-01

    A procedure has been developed which can be used to determine the economic feasibility of solar powered absorption cooling systems. This procedure has been used in a study to investigate the influence of the site-dependent parameters on the economic feasibility of solar absorption cooling. The purpose of this study was to make preliminary site selections for solar powered absorption cooling systems. This paper summarizes the results of that study.

  15. SOLERAS - Saudi University Solar Cooling Laboratories Project. Final report, project summary

    SciTech Connect

    Not Available

    1986-01-01

    Proposals for research on solar cooling are presented for four Saudi Arabian universities. The universities are the University of Petroleum and Minerals in Dhahran, King Saud University in Riyadh, King Abdulaziz University in Jeddah, and King Faisal University in Dammam. Topics researched include the Rankine cycle, passive solar cooling systems, a solar-powered lithium bromide-water absorption machine and a photovoltaic-powered thermoelectric cooling machine. (BCS)

  16. Small Scale Solar Cooling Unit in Climate Conditions of Latvia: Environmental and Economical Aspects

    NASA Astrophysics Data System (ADS)

    Jaunzems, Dzintars; Veidenbergs, Ivars

    2010-01-01

    The paper contributes to the analyses from the environmental and economical point of view of small scale solar cooling system in climate conditions of Latvia. Cost analyses show that buildings with a higher cooling load and full load hours have lower costs. For high internal gains, cooling costs are around 1,7 €/kWh and 2,5 €/kWh for buildings with lower internal gains. Despite the fact that solar cooling systems have significant potential to reduce CO2 emissions due to a reduction of electricity consumption, the economic feasibility and attractiveness of solar cooling system is still low.

  17. Energy-efficient regenerative liquid desiccant drying process

    DOEpatents

    Ko, Suk M.; Grodzka, Philomena G.; McCormick, Paul O.

    1980-01-01

    This invention relates to the use of desiccants in conjunction with an open oop drying cycle and a closed loop drying cycle to reclaim the energy expended in vaporizing moisture in harvested crops. In the closed loop cycle, the drying air is brought into contact with a desiccant after it exits the crop drying bin. Water vapor in the moist air is absorbed by the desiccant, thus reducing the relative humidity of the air. The air is then heated by the used desiccant and returned to the crop bin. During the open loop drying cycle the used desiccant is heated (either fossil or solar energy heat sources may be used) and regenerated at high temperature, driving water vapor from the desiccant. This water vapor is condensed and used to preheat the dilute (wet) desiccant before heat is added from the external source (fossil or solar). The latent heat of vaporization of the moisture removed from the desiccant is reclaimed in this manner. The sensible heat of the regenerated desiccant is utilized in the open loop drying cycle. Also, closed cycle operation implies that no net energy is expended in heating drying air.

  18. Influence of solar variability on the infrared radiative cooling of the thermosphere from 2002 to 2014

    PubMed Central

    Mlynczak, Martin G; Hunt, Linda A; Mertens, Christopher J; Thomas Marshall, B; Russell, James M; Woods, Thomas; Earl Thompson, R; Gordley, Larry L

    2014-01-01

    Infrared radiative cooling of the thermosphere by carbon dioxide (CO2, 15 µm) and by nitric oxide (NO, 5.3 µm) has been observed for 12 years by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument on the Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics satellite. For the first time we present a record of the two most important thermospheric infrared cooling agents over a complete solar cycle. SABER has documented dramatic variability in the radiative cooling on time scales ranging from days to the 11 year solar cycle. Deep minima in global mean vertical profiles of radiative cooling are observed in 2008–2009. Current solar maximum conditions, evidenced in the rates of radiative cooling, are substantially weaker than prior maximum conditions in 2002–2003. The observed changes in thermospheric cooling correlate well with changes in solar ultraviolet irradiance and geomagnetic activity during the prior maximum conditions. NO and CO2 combine to emit 7 × 1018 more Joules annually at solar maximum than at solar minimum. Key Points First record of thermospheric IR cooling rates over a complete solar cycleIR cooling in current solar maximum conditions much weaker than prior maximumVariability in thermospheric IR cooling observed on scale of days to 11 years PMID:26074647

  19. Liquid flat plate collector and pump for solar heating and cooling systems: A collection of quarterly reports

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Progress in the development, fabrication, and delivery of solar subsystems consisting of a solar operated pump, and solar collectors which can be used in solar heating and cooling, or hot water, for single family, multifamily, or commercial applications is reported.

  20. Optimum hot water temperature for absorption solar cooling

    SciTech Connect

    Lecuona, A.; Ventas, R.; Venegas, M.; Salgado, R.; Zacarias, A.

    2009-10-15

    The hot water temperature that maximizes the overall instantaneous efficiency of a solar cooling facility is determined. A modified characteristic equation model is used and applied to single-effect lithium bromide-water absorption chillers. This model is based on the characteristic temperature difference and serves to empirically calculate the performance of real chillers. This paper provides an explicit equation for the optimum temperature of vapor generation, in terms of only the external temperatures of the chiller. The additional data required are the four performance parameters of the chiller and essentially a modified stagnation temperature from the detailed model of the thermal collector operation. This paper presents and discusses the results for small capacity machines for air conditioning of homes and small buildings. The discussion highlights the influence of the relevant parameters. (author)

  1. Solar Heating and Cooling of Residential Buildings: Sizing, Installation and Operation of Systems.

    ERIC Educational Resources Information Center

    Colorado State Univ., Ft. Collins. Solar Energy Applications Lab.

    This training course and a companion course titled "Design of Systems for Solar Heating and Cooling of Residential Buildings," are designed to train home designers and builders in the fundamentals of solar hydronic and air systems for space heating and cooling and domestic hot water heating for residential buildings. Each course, organized in 22…

  2. Solar Heating and Cooling of Buildings: Phase 0. Executive Summary. Final Report.

    ERIC Educational Resources Information Center

    Westinghouse Electric Corp., Baltimore, MD.

    After the Westinghouse Electric Corporation made a comprehensive analysis of the technical, economic, social, environmental, and institutional factors affecting the feasibility of utilizing solar energy for heating and cooling buildings, it determined that solar heating and cooling systems can become competitive in most regions of the country in…

  3. System design package for a solar heating and cooling system installed at Akron, Ohio

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Information used to evaluate the design of a solar heating, cooling, and domestic hot water system is given. A conventional heat pump provides summer cooling items as the design data brochure, system performance specification, system hazard analysis, spare parts list, and detailed design drawings. A solar system is installed in a single-family dwelling at Akron, Ohio, and at Duffield, Virginia.

  4. National Program Plan for Research and Development in Solar Heating and Cooling. Interim Report.

    ERIC Educational Resources Information Center

    Energy Research and Development Administration, Washington, DC. Div. of Solar Energy.

    This report presents the Energy Research and Development Administration (ERDA) program plan for solar heating and cooling of buildings and for agricultural and industrial process applications. An overview of the program plan is followed by a description of the ten paths to the solar heating and cooling of buildings and a brief discussion of the…

  5. Breakthrough Video: Desiccant Enhanced Evaporative Air Conditioning

    SciTech Connect

    2012-01-01

    Researchers at the National Renewable Energy Laboratory (NREL) invented a breakthrough technology that improves air conditioning in a novel way—with heat. NREL combined desiccant materials, which remove moisture from the air using heat, and advanced evaporative technologies to develop a cooling unit that uses 90% less electricity and up to 80% less total energy than traditional air conditioning (AC). This solution, called the desiccant enhanced evaporative air conditioner (DEVAP), also controls humidity more effectively to improve the comfort of people in buildings.

  6. Establish feasibility for providing passive cooling with solar updraft and evaporative downdraft chimneys

    SciTech Connect

    Cunningham, W.A.; Mignon, G.V.; Thompson, T.L.

    1987-01-01

    Natural draft towers can be used for cooling and ventilating structures. From an operational perspective, the downdraft evaporatively cooled tower is preferred for a dry climate. Solar chimneys, when used alone, tend to require an excessively large solar collector area when appreciable quantities of air must be moved. When used in combination with a downdraft tower, the roof and attic of buildings may assist the solar chimney and their use becomes more attractive. Both a frame building and a greenhouse were successfully cooled during this program. The economics of the downdraft tower compare favorably with conventional evaporative cooling for some application.

  7. Establish feasibility for providing passive cooling with solar updraft and evaporate downdraft chimneys

    SciTech Connect

    Cunningham, W.A.; Mignon, G.V.; Thompson, T.L.

    1987-01-01

    Natural draft towers can be used for cooling and ventilating structures. From an operational perspective, the downdraft evaporatively cooled tower is preferred for a dry climate. Solar chimneys, when used alone, tend to require an excessively large solar collector area when appreciable quantities of air must be moved. When used in combination with a downdraft tower, the roof and attic of buildings may assist the solar chimney and their use becomes more attractive. Both a frame building and a greenhouse were successfully cooled during this program. The economics of the downdraft tower compare favorably with conventional evaporative cooling for some applications.

  8. Methodology to determine cost and performance goals for active solar cooling systems

    NASA Astrophysics Data System (ADS)

    Warren, M. L.; Wahlig, M.

    1981-11-01

    Systems analysis is used to calculate the 20 yr. present value of energy savings of solar cooling systems located in Texas, Arizona, Florida, and Washington, DC, and methods of solar system development to meet the cost goals of economic operation are outlined. Solar cooling systems are projected to begin commercial entry in 1986 and reach 20% of the total cooling market by the year 2000, producing 0.14 quads of displaced energy. A numerical simulation was carried out for both residential and commercial solar cooling units with consideration for system cost goals, cost goals per unit collector area, and the cost goals per ton of cooling. System size was targeted as a 3 ton residential chiller and a 25 ton commercial absorption cooling unit. The costs for volume production are provided, along with trends for an incrementally decreasing need for tax incentives, ending in about 1994

  9. Active Desiccant-Based Preconditioning Market Analysis and Product Development

    SciTech Connect

    Fischer, J.

    2001-01-11

    The Phase 1 report (ORNL/Sub/94-SVO44/1), completed earlier in this program, involved a comprehensive field survey and market analysis comparing various specialized outdoor air handling units. This initial investigation included conventional cooling and reheat, conventional cooling with sensible recovery, total energy recovery systems (passive desiccant technology) and various active desiccant systems. The report concluded that several markets do promise a significant sales opportunity for a Climate Changer-based active desiccant system offering. (Climate Changer is a registered trademark of Trane Company.) This initial market analysis defined the wants and needs of the end customers (design engineers and building owners), which, along with subsequent information included in this report, have been used to guide the determination of the most promising active desiccant system configurations. This Phase 2 report begins with a summary of a more thorough investigation of those specific markets identified as most promising for active desiccant systems. Table 1 estimates the annual sales potential for a cost-effective product line of active desiccant systems, such as that built from Climate Changer modules. The Product Development Strategy section describes the active desiccant system configurations chosen to best fit the needs of the marketplace while minimizing system options. Key design objectives based on market research are listed in this report for these active desiccant systems. Corresponding performance goals for the dehumidification wheel required to meet the overall system design objectives are also defined. The Performance Modeling section describes the strategy used by SEMCO to design the dehumidification wheels integrated into the prototype systems currently being tested as part of the U.S. Department of Energy's Advanced Desiccant Technology Program. Actual performance data from wheel testing was used to revise the system performance and energy analysis

  10. Solar energy to heat and cool a new NASA Langley office building

    NASA Technical Reports Server (NTRS)

    Maag, W. L.

    1974-01-01

    A solar heating and cooling system will be installed at a new NASA office building. The objective of this project is to establish a full-scale working test-bed facility to investigate solar energy for heating and cooling buildings. The energy collected will provide between 80 and 100 percent of the heating and cooling requirements during the cool months and between one-half and two-thirds of the cooling requirements in the summer. Thermal energy storage will be provided to bridge the gap between cloudy and clear days.

  11. Desiccant Enhanced Evaporative Air Conditioning: Parametric Analysis and Design; Preprint

    SciTech Connect

    Woods, J.; Kozubal, E.

    2012-10-01

    This paper presents a parametric analysis using a numerical model of a new concept in desiccant and evaporative air conditioning. The concept consists of two stages: a liquid desiccant dehumidifier and a dew-point evaporative cooler. Each stage consists of stacked air channel pairs separated by a plastic sheet. In the first stage, a liquid desiccant film removes moisture from the process (supply-side) air through a membrane. An evaporatively-cooled exhaust airstream on the other side of the plastic sheet cools the desiccant. The second-stage indirect evaporative cooler sensibly cools the dried process air. We analyze the tradeoff between device size and energy efficiency. This tradeoff depends strongly on process air channel thicknesses, the ratio of first-stage to second-stage area, and the second-stage exhaust air flow rate. A sensitivity analysis reiterates the importance of the process air boundary layers and suggests a need for increasing airside heat and mass transfer enhancements.

  12. Liquid-Desiccant Vapor Separation Reduces the Energy Requirements of Atmospheric Moisture Harvesting.

    PubMed

    Gido, Ben; Friedler, Eran; Broday, David M

    2016-08-01

    An innovative atmospheric moisture harvesting system is proposed, where water vapor is separated from the air prior to cooling and condensation. The system was studied using a model that simulates its three interconnected cycles (air, desiccant, and water) over a range of ambient conditions, and optimal configurations are reported for different operation conditions. Model results were compared to specifications of commercial atmospheric moisture harvesting systems and found to represent saving of 5-65% of the electrical energy requirements due to the vapor separation process. We show that the liquid desiccant separation stage that is integrated into atmospheric moisture harvesting systems can work under a wide range of environmental conditions using low grade or solar heating as a supplementary energy source, and that the performance of the combined system is superior. PMID:27435379

  13. Performance of evacuated tubular solar collectors in a residential heating and cooling system

    NASA Astrophysics Data System (ADS)

    Duff, W. S.; Loef, G. O. G.

    1981-03-01

    Operation of CSU Solar House I during the heating season of 1978-1979 and during the 1979 cooling season is discussed. The systems comprised an experimental evacuated tubular solar collector, a nonfreezing aqueous collection medium, heat exchange to an insulated conventional vertical cylindrical storage tank and to a built up rectangular insulated storage tank, heating of circulating air by solar heated water and by electric auxiliary in an off peak heat storage unit, space cooling by lithium bromide absorption chiller, and service water heating by solar exchange and electric auxiliary. The system is compared with CSU Solar Houses I, II and III. The experimental collector provides solar heating and cooling with minimum operational problems. Improved performance, particularly for cooling, resulted from the use of a very well insulated heat storage tank. Day time electric auxiliary heating is avoided by use of off peak electric heat storage.

  14. Solar heating and cooling system installed at RKL Controls Company, Lumberton, New Jersey. Final report

    SciTech Connect

    1981-03-01

    Solar heating and cooling of a 40,000 square foot manufacturing building, sales offices and the solar computer control center/display room are described. Information on system description, test data, major problems and resolutions, performance, operation and maintenance manual, manufacturer's literature and as-built drawings are provided also. The solar system is composed of 6000 square feet of Sunworks double glazed flat plate collectors, external above ground storage subsystem, controls, ARKLA absorption chiller, heat recovery and a cooling tower.

  15. Degradation of desiccants upon contamination: An experimental study

    SciTech Connect

    Pesaran, A A

    1990-11-01

    Experiments were conducted to quantify the effects of thermal cycling and exposure to contamination on solid desiccant materials that may be used in desiccant cooling systems. A test apparatus was used to thermally cycle several desiccant samples and expose them to ambient or contaminated humid air. The source of contamination was cigarette smoke. Six different solid desiccants were tested: two types of silica gel, activated alumina, activated carbon, molecular sieves, and lithium chloride. The exposed desiccant samples were removed after 0.5, 1, 2, 4, or 11 months of exposure and their moisture capacities were measured. Other tests were conducted to characterize pollutants deposited on the exposed samples or to evaluate impact of exposure on internal structure of the samples. Compared to fresh samples, the capacity loss due to thermal cycling with ambient air was generally 10% to 30%. The capacity loss due to only cigarette smoke was generally between 20% to 50%. 7 refs., 8 figs., 3 tabs.

  16. Solar heating and cooling demonstration project at Radian Corporation, Austin, Texas

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The solar heating and cooling system located at the Radian Corporation, Austin, Texas, is discussed. A technical description of the solar system is presented. The costs of the major components and the cost of installing the system are described. Flow diagrams and photographs of the solar system are provided.

  17. How worms survive desiccation

    PubMed Central

    Erkut, Cihan; Penkov, Sider; Fahmy, Karim; Kurzchalia, Teymuras V.

    2012-01-01

    While life requires water, many organisms, known as anhydrobiotes, can survive in the absence of water for extended periods of time. Although discovered 300 years ago, we know very little about the fascinating phenomenon of anhydrobiosis. In this paper, we summarize our previous findings on the desiccation tolerance of the Caenorhabditis elegans dauer larva. A special emphasis is given to the role of trehalose in protecting membranes against desiccation. We also propose a simple mechanism for this process. PMID:24058825

  18. Analysis of the Solar Radiation Impact on Cooling Performance of the Absorption Chiller

    NASA Astrophysics Data System (ADS)

    Fedorčák, Pavol; Košičanová, Danica; Nagy, Richard; Mlynár, Peter

    2014-11-01

    Absorption cooling at low power is a new technology which has not yet been applied to current conditioning elements. This paper analyzes the various elements of solar absorption cooling. Individual states were simulated in which working conditions were set for the capability of solar absorption cooling to balance heat loads in the room. The research is based on an experimental device (absorption units with a performance of 10kW) developed at the STU in Bratislava (currently inputs and outputs of cold sources are being measured). Outputs in this paper are processed so that they connect the entire scheme of the solar absorption cooling system (i.e. the relationship between the solar systems hot and cold storage and the absorption unit). To determine the size of the storage required, calculated cooling for summer months is considered by the ramp rate of the absorption unit and required flow rate of the collectors.

  19. Solar chimney design: Investigating natural ventilation and cooling in offices with the aid of computer simulation

    NASA Astrophysics Data System (ADS)

    Angelis, Nikolaos

    Solar chimney design is investigated as a means of improving natural ventilation and passive cooling in office buildings. Existing scientific research and built precedents are generally limited literature review findings on various features of solar chimneys were categorised and used to develop a building simulation strategy. Using UK climatic data, simulations were performed on several computer models in order to investigate solar chimney performance during a single day period and an entire cooling season. Passive cooling with a solar chimney is possible but actual reduction in temperatures in most cases examined could be negligible. Cooling potential is increased on still, warm days, while the prospects for night cooling are further improved. A solar chimney may help reduce considerably the occurrence of resultant temperatures at or above the 25 C and 28 C thresholds. Solar chimney width, height, apertures and integral use of thermal mass are the most significant parameters for cooling. Simulation results showed that a solar chimney can increase significantly natural ventilation rates. Total ventilation rates may be increased by at least 22%. During still days a solar chimney can enhance ventilation rates by 36% or more. Stack ventilation through a solar chimney is typically 20% of cross ventilation during night time this may increase to at least 40-45% and on still days it may reach 100% of typical cross ventilation rates. Solar chimney induced stack ventilation and cross ventilation are interrelated. Resultant air flow patterns may have an important effect on convective heat transfers and thermal comfort. Climate and microclimate conditions should be an integral part of solar chimney design. Key aspects and recommendations regarding solar chimneys, passive cooling and natural ventilation are provided for design guidance and feedback in further research.

  20. Performance evaluation of an active solar cooling system utilizing low cost plastic collectors and an evaporatively-cooled absorption chiller

    NASA Astrophysics Data System (ADS)

    Lof, G. O.; Westhoff, M. A.; Karaki, S.

    1984-02-01

    During the summer of 1982, air conditioning in Solar House 3 at Colorado State University was provided by an evaporatively-cooled absorption chiller. The single-effect lithium bromide chiller is an experimental three-ton unit from which heat is rejected by direct evaporative cooling of the condenser and absorber walls, thereby eliminating the need for a separate cooling tower. Domestic hot water was also provided by use of a double-walled heat exchanger and 80-gal hot water tank. A schematic of the system is given. Objectives of the project were: (1) evaluation of system performance over the course of one cooling season in Fort Collins, Colorado; (2) optimization of system operation and control; (3) development of a TRNSYS compatible model of the chiller; and (4) determination of cooling system performance in several U.S. climates by use of the model.

  1. Polymers as advanced materials for desiccant applications

    SciTech Connect

    Czanderna, A.W.

    1990-12-01

    This research is concerned with solid materials used as desiccants for desiccant cooling systems (DCSs) that process water vapor in an atmosphere to produce cooling. Background information includes an introduction to DCSs and the role of the desiccant as a system component. The water vapor sorption performance criteria used for screening the modified polymers prepared include the water sorption capacity from 5% to 80% relative humidity (R.H.), isotherm shape, and rate of adsorption and desorption. Measurements are presented for the sorption performance of modified polymeric advanced desiccant materials with the quartz crystal microbalance. Isotherms of polystyrene sulfonic acid (PSSA) taken over a 5-month period show that the material has a dramatic loss in capacity and that the isotherm shape is time dependent. The adsorption and desorption kinetics for PSSA and all the ionic salts of it studied are easily fast enough for commercial DCS applications with a wheel rotation speed of 6 min per revolution. Future activities for the project are addressed, and a 5-year summary of the project is included as Appendix A. 34 refs., 20 figs., 3 tabs.

  2. Subsystem design package for Mod 2 site data acquisition system: Solar heating and cooling

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The Mod II Site Data Acquisition Subsystem (SDAS) is designed to collect data from sensors located on residential or commercial buildings using a solar heating and/or cooling system. The SDAS takes the data obtained from sensors located on the solar heating and/or cooling system, processes the data into a suitable format, stores the data for a period of time, and provides the capability for both telephone retrieval by the Central Data Processing System (CDPS) and manual retrieval of the data for transfer to the central site. The unit is designed so it will not degrade the operation of the solar heating/cooling system which it is monitoring.

  3. The NASA-Lewis/ERDA solar heating and cooling technology program. [project planning/energy policy

    NASA Technical Reports Server (NTRS)

    Couch, J. P.; Bloomfield, H. S.

    1975-01-01

    Plans by NASA to carry out a major role in a solar heating and cooling program are presented. This role would be to create and test the enabling technology for future solar heating, cooling, and combined heating/cooling systems. The major objectives of the project are to achieve reduction in solar energy system costs, while maintaining adequate performance, reliability, life, and maintenance characteristics. The project approach is discussed, and will be accomplished principally by contract with industry to develop advanced components and subsystems. Advanced hardware will be tested to establish 'technology readiness' both under controlled laboratory conditions and under real sun conditions.

  4. Survey and evaluation of available thermal insulation materials for use on solar heating and cooling systems

    SciTech Connect

    Not Available

    1980-03-01

    This is the final report of a survey and evaluation of insulation materials for use with components of solar heating and cooling systems. The survey was performed by mailing questionnaires to manufacturers of insulation materials and by conducting an extensive literature search to obtain data on relevant properties of various types of insulation materials. The study evaluated insulation materials for active and passive solar heating and cooling systems and for multifunction applications. Primary and secondary considerations for selecting insulation materials for various components of solar heating and cooling systems are presented.

  5. The development of a solar-powered residential heating and cooling system

    NASA Technical Reports Server (NTRS)

    1974-01-01

    Efforts to demonstrate the engineering feasibility of utilizing solar power for residential heating and cooling are described. These efforts were concentrated on the analysis, design, and test of a full-scale demonstration system which is currently under construction at the National Aeronautics and Space Administration, Marshall Space Flight Center, Huntsville, Alabama. The basic solar heating and cooling system under development utilizes a flat plate solar energy collector, a large water tank for thermal energy storage, heat exchangers for space heating and water heating, and an absorption cycle air conditioner for space cooling.

  6. Site dependent factors affecting the economic feasibility of solar powered absorption cooling

    NASA Technical Reports Server (NTRS)

    Bartlett, J. C.

    1978-01-01

    A procedure was developed to evaluate the cost effectiveness of combining an absorption cycle chiller with a solar energy system. A basic assumption of the procedure is that a solar energy system exists for meeting the heating load of the building, and that the building must be cooled. The decision to be made is to either cool the building with a conventional vapor compression cycle chiller or to use the existing solar energy system to provide a heat input to the absorption chiller. Two methods of meeting the cooling load not supplied by solar energy were considered. In the first method, heat is supplied to the absorption chiller by a boiler using fossil fuel. In the second method, the load not met by solar energy is net by a conventional vapor compression chiller. In addition, the procedure can consider waste heat as another form of auxiliary energy. Commercial applications of solar cooling with an absorption chiller were found to be more cost effective than the residential applications. In general, it was found that the larger the chiller, the more economically feasible it would be. Also, it was found that a conventional vapor compression chiller is a viable alternative for the auxiliary cooling source, especially for the larger chillers. The results of the analysis gives a relative rating of the sites considered as to their economic feasibility of solar cooling.

  7. Initial operation of a solar heating and cooling system in a full-scale solar building test facility

    NASA Technical Reports Server (NTRS)

    Knoll, R. H.; Miao, D.; Hamlet, I. L.; Jensen, R. N.

    1976-01-01

    The Solar Building Test Facility (SBTF) located at Hampton, Virginia became operational in early summer of 1976. This facility is a joint effort by NASA-Lewis and NASA-Langley to advance the technology for heating and cooling of office buildings with solar energy. Its purposes are to (1) test system components which include high-performing collectors, (2) test performance of complete solar heating and cooling system, (3) investigate component interactions and (4) investigate durability, maintenance and reliability of components. The SBTF consists of a 50,000 square foot office building modified to accept solar heated water for operation of an absorption air conditioner and for the baseboard heating system. A 12,666 square foot solar collector field with a 30,000 gallon storage tank provides the solar heated water. A description of the system and the collectors selected is given here, along with the objectives, test approach, expected system performance and some preliminary results.

  8. Initial operation of a solar heating and cooling system in a full-scale solar building test facility

    NASA Technical Reports Server (NTRS)

    Knoll, R. H.; Miao, D.; Hamlet, I. L.; Jensen, R. N.

    1976-01-01

    The Solar Building Test Facility (SBTF) was constructed to advance the technology for heating and cooling of office buildings with solar energy. Its purposes are to (1) test system components which include high-performing collectors, (2) test the performance of a complete solar heating and cooling system, (3) investigate component interactions, and (4) investigate durability, maintenance and reliability of components. The SBTF consists of a 50,000 square foot office building modified to accept solar heated water for operation of an absorption air conditioner and for the baseboard heating system. A 12,666 square foot solar collector field with a 30,000 gallon storage tank provides the solar heated water. A description of the system and the collectors selected is printed along with the objectives, test approach, expected system performance, and some preliminary results.

  9. Characterization of selected application of biomass energy technologies and a solar district heating and cooling system

    SciTech Connect

    D'Alessio, Dr., Gregory J.; Blaunstein, Robert P.

    1980-09-01

    The following systems are discussed: energy self-sufficient farms, wood gasification, energy from high-yield silviculture farms, and solar district heating and cooling. System descriptions and environmental data are included for each one. (MHR)

  10. Development and testing of heat transport fluids for use in active solar heating and cooling systems

    NASA Technical Reports Server (NTRS)

    Parker, J. C.

    1981-01-01

    Work on heat transport fluids for use with active solar heating and cooling systems is described. Program objectives and how they were accomplished including problems encountered during testing are discussed.

  11. Passive solar space heating and cooling. (Latest citations from the NTIS Bibliographic database). NewSearch

    SciTech Connect

    Not Available

    1994-10-01

    The bibliography contains citations concerning the passive use of solar energy for space heating and cooling in buildings, houses, and homes. Citations discuss the design, performance, models, and economic analysis of heating and cooling systems. Topics include solar architecture, energy consumption analysis, energy conservation, and heat recovery. Also included are thermal comfort, quality of life, and housing for the elderly. (Contains a minimum of 209 citations and includes a subject term index and title list.)

  12. ERDA/NASA-MSFC solar heating and cooling development and demonstration program

    NASA Technical Reports Server (NTRS)

    Price, J. M.

    1977-01-01

    The role of the Manned Space Flight Center (MSFC) in the National Solar Heating and Cooling program is evaluated. The responsibilities of the MSFC within this program are (1) to manage the development and testing of solar heating and cooling systems leading to marketable products, (2) to develop data acquisition equipment supporting a national data program, and (3) to manage and collect data from commercial demonstration sites. MSFC test facilities and demonstration sites are described.

  13. Solar Heating and Cooling of Buildings (Phase O). Volume 1: Executive Summary.

    ERIC Educational Resources Information Center

    TRW Systems Group, Redondo Beach, CA.

    The purpose of this study was to establish the technical and economic feasibility of using solar energy for the heating and cooling of buildings. Five selected building types in 14 selected cities were used to determine loads for space heating, space cooling and dehumidification, and domestic service hot water heating. Relying on existing and…

  14. Cooling-load implications for residential passive-solar-heating systems

    SciTech Connect

    Jones, R.W.; McFarland, R.D.

    1983-01-01

    Ongoing research on quantifying the cooling loads in residential buildings, particularly buildings with passive solar heating systems, is described, along with the computer simulation model used for calculating cooling loads. A sample of interim results is also presented. The objective of the research is to develop a simple analysis method, useful early in design, to estimate the annual cooling energy requirement of a given building.

  15. Observational and Modeling Study of Pickup Ion Cooling Behavior in Solar Wind Compression and Rarefaction Regions

    NASA Astrophysics Data System (ADS)

    Chen, J.; Moebius, E.; Schwadron, N.; Klecker, B.; Bzowski, M.; Galvin, A. B.; Isenberg, P. A.; Sokol, J. M.; Gorby, M.; Bochsler, P. A.

    2013-12-01

    In many previous studies, the velocity distribution function of interstellar pickup ions (PUIs), which are produced by ionization of interstellar neutral atoms in the solar wind, were described as evolving through fast pitch angle scattering followed by adiabatic cooling during radial transport with in the reference frame of the solar wind [e.g., Vasyliunas & Siscoe, 1976 VS76 hereafter]. In the VS76 model, the slope of the velocity distributions is controlled by the combination of the ionization rate and the cooling process. Recently, Chen et al. [2013] have shown that the related adiabatic cooling index varies with solar activity between ~1 and 2, compared with 1.5 predicted by the VS76 model. Contributors to the observed variations include solar wind compression and rarefaction regions. Here, we performed a statistical study of the PUI cooling behavior in solar wind compression and rarefaction regions based on STEREO-A PLASTIC data sets using a set of events from the co-rotating interaction region (CIR) list (http://www-scc.igpp.ucla.edu/forms/stereo/stereo_level_3.html). We found that PUIs undergo stronger cooling in rarefaction regions and weaker cooling in compression regions. In order to analyze the PUI cooling behavior under these conditions, we modeled the PUI velocity distributions in CIRs using the Energetic Particle Radiation Environment Module (EPREM) [Schwadron et al., 2010]. For this analysis, we adopted a magneto-hydrodynamic CIR model proposed by [Giacalone et al., 2002]. The resulting PUI distributions exhibit a flatter slope in the compression region and are steeper in the rarefaction region compared with those in the undisturbed solar wind, in accordance with STEREO observations. These results indicate that gradients in the solar wind speed, as observed in CIRs, have substantial effects on the PUI cooling process.

  16. Cooling of solar flares plasmas. 1: Theoretical considerations

    NASA Technical Reports Server (NTRS)

    Cargill, Peter J.; Mariska, John T.; Antiochos, Spiro K.

    1995-01-01

    Theoretical models of the cooling of flare plasma are reexamined. By assuming that the cooling occurs in two separate phase where conduction and radiation, respectively, dominate, a simple analytic formula for the cooling time of a flare plasma is derived. Unlike earlier order-of-magnitude scalings, this result accounts for the effect of the evolution of the loop plasma parameters on the cooling time. When the conductive cooling leads to an 'evaporation' of chromospheric material, the cooling time scales L(exp 5/6)/p(exp 1/6), where the coronal phase (defined as the time maximum temperature). When the conductive cooling is static, the cooling time scales as L(exp 3/4)n(exp 1/4). In deriving these results, use was made of an important scaling law (T proportional to n(exp 2)) during the radiative cooling phase that was forst noted in one-dimensional hydrodynamic numerical simulations (Serio et al. 1991; Jakimiec et al. 1992). Our own simulations show that this result is restricted to approximately the radiative loss function of Rosner, Tucker, & Vaiana (1978). for different radiative loss functions, other scaling result, with T and n scaling almost linearly when the radiative loss falls off as T(exp -2). It is shown that these scaling laws are part of a class of analytic solutions developed by Antiocos (1980).

  17. Tests of a reduced-scale experimental model of a building solar heating-cooling system

    NASA Technical Reports Server (NTRS)

    Namkoong, D.

    1976-01-01

    An experimental solar heating and cooling system model has been built and operated, combining elements that are programmable (e.g., heating and cooling load of a building and collected solar energy) with experimental equipment. The experimental system model was based on the loads and components used in the Solar Building Test Facility (SBTF), which includes a 1394 sq m solar collector field at NASA Langley. These tests covered 5 continuous days under summer conditions. For the system model up to 55 percent of the simulated collected solar energy was used for the building load. This amount of solar energy supplied 35 percent of the building cooling load. Heat loss was significant. If tank heat loss were eliminated, which would make it similar to the actual SBTF, 75 percent of the collected solar energy would be used. This amount would supply approximately 50 percent of the building cooling load. A higher fraction of solar energy is possible with a more performance-optimized system.

  18. Timonium Elementary School Solar Energy Heating and Cooling Augmentation Experiment. Final Engineering Report. Executive Summary.

    ERIC Educational Resources Information Center

    AAI Corp., Baltimore, MD.

    This report covers a two-year and seven-month solar space heating and cooling experiment conducted at the Timonium Elementary School, Timonium, Maryland. The system was designed to provide a minimum of 50 percent of the energy required during the heating season and to determine the feasibility of using solar energy to power absorption-type…

  19. Solar Heating and Cooling Experiment for a School in Atlanta. Performance Report.

    ERIC Educational Resources Information Center

    Westinghouse Electric Corp., Falls Church, VA.

    This report documents the performance and conclusions of a 13-month period of monitoring the performance of the experimental solar heating and cooling system installed in the George A. Towns Elementary School, Atlanta, Georgia. The objectives of the project were to (1) make a significant contribution to solar design, technology, and acceptability;…

  20. Operations manual: On Site Monitor (OSM), solar heating and cooling systems

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The on-site monitor is a portable device which, when connected to a solar system site data acquisition subsystem; allows readouts of clock and sensor data in voltage or engineering units at instrumented solar heating and cooling sites. The unit is described and procedures for its proper operation are presented.

  1. Heat-stop structure design with high cooling efficiency for large ground-based solar telescope.

    PubMed

    Liu, Yangyi; Gu, Naiting; Rao, Changhui; Li, Cheng

    2015-07-20

    A heat-stop is one of the most important thermal control devices for a large ground-based solar telescope. For controlling the internal seeing effect, the temperature difference between the heat-stop and the ambient environment needs to be reduced, and a heat-stop with high cooling efficiency is required. In this paper, a novel design concept for the heat-stop, in which a multichannel loop cooling system is utilized to obtain higher cooling efficiency, is proposed. To validate the design, we analyze and compare the cooling efficiency for the multichannel and existing single-channel loop cooling system under the same conditions. Comparative results show that the new design obviously enhances the cooling efficiency of the heat-stop, and the novel design based on the multichannel loop cooling system is obviously better than the existing design by increasing the thermal transfer coefficient. PMID:26367826

  2. System design package for the solar heating and cooling central data processing system

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The central data processing system provides the resources required to assess the performance of solar heating and cooling systems installed at remote sites. These sites consist of residential, commercial, government, and educational types of buildings, and the solar heating and cooling systems can be hot-water, space heating, cooling, and combinations of these. The instrumentation data associated with these systems will vary according to the application and must be collected, processed, and presented in a form which supports continuity of performance evaluation across all applications. Overall software system requirements were established for use in the central integration facility which transforms raw data collected at remote sites into performance evaluation information for assessing the performance of solar heating and cooling systems.

  3. Integrated Modeling of Building Energy Requirements IncorporatingSolar Assisted Cooling

    SciTech Connect

    Firestone, Ryan; Marnay, Chris; Wang, Juan

    2005-08-10

    This paper expands on prior Berkeley Lab work on integrated simulation of building energy systems by the addition of active solar thermal collecting devices, technology options not previously considered (Siddiqui et al 2005). Collectors can be used as an alternative or additional source of hot water to heat recovery from reciprocating engines or microturbines. An example study is presented that evaluates the operation of solar assisted cooling at a large mail sorting facility in southern California with negligible heat loads and year-round cooling loads. Under current conditions solar thermal energy collection proves an unattractive option, but is a viable carbon emission control strategy.

  4. System design package for solar heating and cooling site data acquisition subsystem

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The Site Data Acquisition Subsystem (SDAS) designed to collect data from sensors located on residential or commercial buildings using a solar heating and/or cooling system is described. It takes the data obtained from sensors located on the solar system, processes the data into suitable format, stores the data for a period of time, and provides the capability for either telephone retrieval by the central data processing system or manual retrieval of the data for transfer to a central site. The SDAS is also designed so that it will not degrade the operation of the solar heating/cooling system which it is monitoring.

  5. Design and operation of a solar heating and cooling system for a residential size building

    NASA Technical Reports Server (NTRS)

    Littles, J. W.; Humphries, W. R.; Cody, J. C.

    1978-01-01

    The first year of operation of solar house is discussed. Selected design information, together with a brief system description is included. The house was equipped with an integrated solar heating and cooling system which uses fully automated state-of-the art. Evaluation of the data indicate that the solar house heating and cooling system is capable of supplying nearly 100 percent of the thermal energy required for heating and approximately 50 percent of the thermal energy required to operate the absorption cycle air conditioner.

  6. Comparison of solar panel cooling system by using dc brushless fan and dc water

    NASA Astrophysics Data System (ADS)

    Irwan, Y. M.; Leow, W. Z.; Irwanto, M.; M, Fareq; Hassan, S. I. S.; Safwati, I.; Amelia, A. R.

    2015-06-01

    The purpose of this article is to discuss comparison of solar panel cooling system by using DC brushless fan and DC water pump. Solar photovoltaic (PV) power generation is an interesting technique to reduce non-renewable energy consumption and as a renewable energy. The temperature of PV modules increases when it absorbs solar radiation, causing a decrease in efficiency. A solar cooling system is design, construct and experimentally researched within this work. To make an effort to cool the PV module, Direct Current (DC) brushless fan and DC water pump with inlet/outlet manifold are designed for constant air movement and water flow circulation at the back side and front side of PV module representatively. Temperature sensors were installed on the PV module to detect temperature of PV. PIC microcontroller was used to control the DC brushless fan and water pump for switch ON or OFF depend on the temperature of PV module automatically. The performance with and without cooling system are shown in this experiment. The PV module with DC water pump cooling system increase 3.52%, 36.27%, 38.98%in term of output voltage, output current, output power respectively. It decrease 6.36 °C compare than to PV module without DC water pump cooling system. While DC brushless fan cooling system increase 3.47%, 29.55%, 32.23%in term of output voltage, output current, and output power respectively. It decrease 6.1 °C compare than to PV module without DC brushless fan cooling system. The efficiency of PV module with cooling system was increasing compared to PV module without cooling system; this is because the ambient temperature dropped significantly. The higher efficiency of PV cell, the payback period of the system can be shorted and the lifespan of PV module can also be longer.

  7. Characterization of a starch based desiccant wheel dehumidifier

    NASA Astrophysics Data System (ADS)

    Beery, Kyle Edward

    Starch, cellulose, and hemicellulose have an affinity for water, and adsorb water vapor from air. Materials made from combinations of these biobased sugar polymers also have been found to possess adsorptive properties. An interesting possible application of these starch-based adsorbents is the desiccant wheel dehumidifier. The desiccant wheel dehumidifier is used in conjunction with a standard air conditioning system. In this process, ambient air is passed through a stationary section while a wheel packed with desiccant rotates through that section. The desiccant adsorbs humidity (latent load) from the air, and the air conditioning system then cools the air (sensible load). Several starch based adsorbents were developed and tested for adsorptive capacity in a new high throughput screening system. The best formulations from the high throughput screening system, also taking into account economic considerations and structural integrity, were considered for use in the desiccant wheel dehumidifier. A suitable adsorbent was chosen and formulated into a matrix structure for the desiccant wheel system. A prototype desiccant wheel system was constructed and the performance was investigated under varying regeneration temperatures and rotation speeds. The results from the experiments showed that the starch based desiccant wheel dehumidification system does transfer moisture from the inlet process stream to the outlet regeneration stream. The DESSIM model was modified for the starch based adsorbent and compared to the experimental results. Also, the results when the wheel parameters were varied were compared to the predicted results from the model. The results given by the starch based desiccant wheel system show the desired proof of concept.

  8. Desiccation tolerance of prokaryotes.

    PubMed

    Potts, M

    1994-12-01

    The removal of cell-bound water through air drying and the addition of water to air-dried cells are forces that have played a pivotal role in the evolution of the prokaryotes. In bacterial cells that have been subjected to air drying, the evaporation of free cytoplasmic water (Vf) can be instantaneous, and an equilibrium between cell-bound water (Vb) and the environmental water (vapor) potential (psi wv) may be achieved rapidly. In the air-dried state some bacteria survive only for seconds whereas others can tolerate desiccation for thousands, perhaps millions, of years. The desiccated (anhydrobiotic) cell is characterized by its singular lack of water--with contents as low as 0.02 g of H2O g (dry weight)-1. At these levels the monolayer coverage by water of macromolecules, including DNA and proteins, is disturbed. As a consequence the mechanisms that confer desiccation tolerance upon air-dried bacteria are markedly different from those, such as the mechanism of preferential exclusion of compatible solutes, that preserve the integrity of salt-, osmotically, and freeze-thaw-stressed cells. Desiccation tolerance reflects a complex array of interactions at the structural, physiological, and molecular levels. Many of the mechanisms remain cryptic, but it is clear that they involve interactions, such as those between proteins and co-solvents, that derive from the unique properties of the water molecule. A water replacement hypothesis accounts for how the nonreducing disaccharides trehalose and sucrose preserve the integrity of membranes and proteins. Nevertheless, we have virtually no insight into the state of the cytoplasm of an air-dried cell. There is no evidence for any obvious adaptations of proteins that can counter the effects of air drying or for the occurrence of any proteins that provide a direct and a tangible contribution to cell stability. Among the prokaryotes that can exist as anhydrobiotic cells, the cyanobacteria have a marked capacity to do so. One

  9. Desiccation tolerance of prokaryotes.

    PubMed Central

    Potts, M

    1994-01-01

    The removal of cell-bound water through air drying and the addition of water to air-dried cells are forces that have played a pivotal role in the evolution of the prokaryotes. In bacterial cells that have been subjected to air drying, the evaporation of free cytoplasmic water (Vf) can be instantaneous, and an equilibrium between cell-bound water (Vb) and the environmental water (vapor) potential (psi wv) may be achieved rapidly. In the air-dried state some bacteria survive only for seconds whereas others can tolerate desiccation for thousands, perhaps millions, of years. The desiccated (anhydrobiotic) cell is characterized by its singular lack of water--with contents as low as 0.02 g of H2O g (dry weight)-1. At these levels the monolayer coverage by water of macromolecules, including DNA and proteins, is disturbed. As a consequence the mechanisms that confer desiccation tolerance upon air-dried bacteria are markedly different from those, such as the mechanism of preferential exclusion of compatible solutes, that preserve the integrity of salt-, osmotically, and freeze-thaw-stressed cells. Desiccation tolerance reflects a complex array of interactions at the structural, physiological, and molecular levels. Many of the mechanisms remain cryptic, but it is clear that they involve interactions, such as those between proteins and co-solvents, that derive from the unique properties of the water molecule. A water replacement hypothesis accounts for how the nonreducing disaccharides trehalose and sucrose preserve the integrity of membranes and proteins. Nevertheless, we have virtually no insight into the state of the cytoplasm of an air-dried cell. There is no evidence for any obvious adaptations of proteins that can counter the effects of air drying or for the occurrence of any proteins that provide a direct and a tangible contribution to cell stability. Among the prokaryotes that can exist as anhydrobiotic cells, the cyanobacteria have a marked capacity to do so. One

  10. Design of a test facility for gas-fired desiccant-based air conditioning systems

    SciTech Connect

    Jalalzadeh-Azar, A.A.; Steele, W.G.; Hodge, B.K.

    1996-12-31

    The design of a facility for testing desiccant-based air conditioning systems is presented. The determination of the performance parameters of desiccant systems is discussed including moisture removal capacity, latent and total cooling capacities, and efficiency indexes. The appropriate procedures and key measurements for determining these parameters are identified using uncertainty analysis.

  11. Enhancing photovoltaic efficiency through radiative cooling of solar cells below ambient temperature

    NASA Astrophysics Data System (ADS)

    Safi, Taqiyyah; Munday, Jeremy

    Sunlight heats up solar cells and the resulting elevated solar cell temperature adversely effects the photovoltaic efficiency and the reliability of the cell. Currently, a variety of active and passive cooling strategies are used to lower the operating temperature of the solar cell. Passive radiative cooling requires no energy input, and is ideal for solar cells; however, previously demonstrated devices still operate above the ambient, leading to a lower efficiency as compared to the ideal Shockley-Queisser limit, which is defined for a cell in contact with an ideal heat sink at ambient temperature (300 K). In this talk, we will describe the use of radiative cooling techniques to lower the cell temperature below the ambient temperature. We show that by combining specifically designed radiative cooling structures with solar cells, efficiencies higher than the limiting efficiency achievable at 300 K can be obtained for solar cells in both terrestrial and extraterrestrial environments. We show that these structures yield an efficiency 0.87% higher than a typical PV module at operating temperatures in a terrestrial application. We also demonstrate an efficiency advantage of 0.4-2.6% for cells in an extraterrestrial environment in near-earth orbit.

  12. Hardware problems encountered in solar heating and cooling systems

    NASA Technical Reports Server (NTRS)

    Cash, M.

    1978-01-01

    Numerous problems in the design, production, installation, and operation of solar energy systems are discussed. Described are hardware problems, which range from simple to obscure and complex, and their resolution.

  13. CSU Solar Housee III solar heating and cooling system performance. Annual report: technical summary, 1 October 1978-30 September 1979

    SciTech Connect

    Ward, D.S.; Ward, J.C.; Oberoi, H.S.

    1980-10-01

    The objective of this study was to test and evaluate the practicality of an integrated flat-plate state-of-the-art liquid-heating solar collector and absorption cooling system installed on Colorado State University (CSU) Solar House III. This objective was accomplished by designing and installing a complete solar heating and cooling system (including appropriate data acquisition equipment and instrumentation), performing a detailed analysis and evaluation of all aspects of the solar system, and comparing the seasonal performance of the system with two other solar heating and cooling systems installed in adjacent buildings with virtually identical thermal characteristics.

  14. Solar-heating and cooling system design package

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Package of information includes design data, performance specifications, drawings, hazard analysis, and spare parts list for commercially produced system installed in single-family dwelling in Akron, Ohio. System uses air flat-plate collectors, 12000 kg rock storage and backup heat pump. Solar portion requires 0.7 kW, and provides 35% of average total heating load including hot water. Information aids persons considering installing solar home-heating systems.

  15. Twelve solar-heating/cooling systems: Design and development

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Two quarterly reports describe first 6 months of development on single family, multifamily, and commercial installations in Minneapolis area. Reports discuss basic requirements, and reasons for selecting specific configurations. Systems consist of liquid cooled flat plate collectors, two fluid loops, and gas-fired forced-air auxiliary heat source.

  16. RS-600 programmable controller: Solar heating and cooling

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Three identical microprocessor control subsystems were developed which can be used in heating, heating and cooling, and/or hot water systems for single family, multifamily, or commercial applications. The controller incorporates a low cost, highly reliable (all solid state) microprocessor which can be easily reprogrammed.

  17. Impact of Hybrid Wet/Dry Cooling on Concentrating Solar Power Plant Performance

    SciTech Connect

    Wagner, M. J.; Kutscher, C.

    2010-01-01

    This paper examines the sensitivity of Rankine cycle plant performance to dry cooling and hybrid (parallel) wet/dry cooling combinations with the traditional wet-cooled model as a baseline. Plants with a lower temperature thermal resource are more sensitive to fluctuations in cooling conditions, and so the lower temperature parabolic trough plant is analyzed to assess the maximum impact of alternative cooling configurations. While low water-use heat rejection designs are applicable to any technology that utilizes a Rankine steam cycle for power generation, they are of special interest to concentrating solar power (CSP) technologies that are located in arid regions with limited water availability. System performance is evaluated using hourly simulations over the course of a year at Daggett, CA. The scope of the analysis in this paper is limited to the power block and the heat rejection system, excluding the solar field and thermal storage. As such, water used in mirror washing, maintenance, etc., is not included. Thermal energy produced by the solar field is modeled using NREL's Solar Advisor Model (SAM).

  18. Solar heating and cooling system installed at RKL Controls Company, Lumberton, New Jersey

    NASA Astrophysics Data System (ADS)

    1981-03-01

    The final results of the design and operation of a computer controlled solar heated and cooled 40,000 square foot manufacturing building, sales office, and computer control center/display room are summarized. The system description, test data, major problems and resolutions, performance, operation and maintenance manual, equipment manufacturers' literature, and as-built drawings are presented. The solar system is composed of 6,000 square feet of flat plate collectors, external above ground storage subsystem, controls, absorption chiller, heat recovery, and a cooling tower.

  19. Solar heating and cooling with the CaCl2-CH3OH chemical heat pump

    NASA Astrophysics Data System (ADS)

    Offenhartz, P. O.

    1982-03-01

    A chemical heat pump based on the reaction of calcium chloride and methanol is being designed and optimized for solar heating and air conditioning, primarily for the residential and light commercial market. The performance requirements for this application are quite stringent. For example, to minimize maintenance, a cooling tower should not be used, and the solar collectors should be fixed rooftop flat plates or evacuated tubes. The chiller should be capable of reaching 45 F on a 95 F day in order to provide effective dehumidification. Energy storage for late afternoon and early evening cooling, as well as night time winter heating, must be provided.

  20. Establishing feasibility for providing passive cooling with solar updraft and evaporative downdraft chimneys

    SciTech Connect

    Cunningham, W.A.; Mignon, G.V.

    1986-01-01

    At the present time all experimental towers (chimneys) are completed and operating. This consists of both a solar updraft and a natural-evaporative downdraft tower retrofitted to an existing residence structure and a greenhouse. The residential, experimental, natural-draft cooling system was completed in May, 1985, and five months of summer data on a Hewlet Packard 85 data acquisition computer with a digital voltmeter were acquired. The cooling tower and solar chimney on the experimental greenhouse became operational in September of 1985. A conceptual drawing of both the greenhouse and the residence natural-draft towers is included in the appendix along with the September 85 progress report.

  1. Solar heating and cooling system installed at RKL Controls Company, Lumberton, New Jersey

    NASA Technical Reports Server (NTRS)

    1981-01-01

    The final results of the design and operation of a computer controlled solar heated and cooled 40,000 square foot manufacturing building, sales office, and computer control center/display room are summarized. The system description, test data, major problems and resolutions, performance, operation and maintenance manual, equipment manufacturers' literature, and as-built drawings are presented. The solar system is composed of 6,000 square feet of flat plate collectors, external above ground storage subsystem, controls, absorption chiller, heat recovery, and a cooling tower.

  2. Solar heating, cooling, and hot water systems installed at Richland, Washington

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The project described is part of the U. S. Department of Energy's solar demonstration program, and became operational in April 1978. The solar system uses 6,000 square feet of flat-plate liquid collectors in a closed loop to deliver solar energy through a liquid-liquid heat exchanger to the building heat-pump duct work or 9,000-gallon thermal energy storage tank. A 25-ton Arkla solar-driven absorption chiller provides the cooling, in conjunction with a 2,000 gallon chilled water storage tank and reflective ponds on three sides of the building surplus heat. A near-by building is essentially identical except for having conventional heat-pump heating and cooling, and can serve as an experimental control. An on-going public relations program was provided from the beginning of the program, and resulted in numerous visitors and tour groups.

  3. Radiative cooling of solar absorbers using a visibly transparent photonic crystal thermal blackbody.

    PubMed

    Zhu, Linxiao; Raman, Aaswath P; Fan, Shanhui

    2015-10-01

    A solar absorber, under the sun, is heated up by sunlight. In many applications, including solar cells and outdoor structures, the absorption of sunlight is intrinsic for either operational or aesthetic considerations, but the resulting heating is undesirable. Because a solar absorber by necessity faces the sky, it also naturally has radiative access to the coldness of the universe. Therefore, in these applications it would be very attractive to directly use the sky as a heat sink while preserving solar absorption properties. Here we experimentally demonstrate a visibly transparent thermal blackbody, based on a silica photonic crystal. When placed on a silicon absorber under sunlight, such a blackbody preserves or even slightly enhances sunlight absorption, but reduces the temperature of the underlying silicon absorber by as much as 13 °C due to radiative cooling. Our work shows that the concept of radiative cooling can be used in combination with the utilization of sunlight, enabling new technological capabilities. PMID:26392542

  4. Monitoring of the performance of a solar heated and cooled apartment building

    NASA Astrophysics Data System (ADS)

    Vliet, G. C.; Srubar, R. L.

    1980-03-01

    An all electric apartment building in Texas was retrofitted for solar heating and cooling and hot water. The system consisted of an array of 1280 square feet of Northrup concentrating tracking collectors, a 5000 gallon hot water storage vessel, a 500 gallon chilled water storage vessel, a 25 ton Arkla Industries absorption chiller, and a two pipe hydronic air conditioning system. The solar air conditioning equipment was installed in parallel with the existing conventional electric heating and cooling system, and the solar domestic water heating served as preheat to the existing electric water heaters. The system was fully instrumented for monitoring. Detailed descriptions of the solar system, the performance monitoring system, and the data reduction processes are given.

  5. Radiative cooling of solar absorbers using a visibly transparent photonic crystal thermal blackbody

    PubMed Central

    Zhu, Linxiao; Raman, Aaswath P.; Fan, Shanhui

    2015-01-01

    A solar absorber, under the sun, is heated up by sunlight. In many applications, including solar cells and outdoor structures, the absorption of sunlight is intrinsic for either operational or aesthetic considerations, but the resulting heating is undesirable. Because a solar absorber by necessity faces the sky, it also naturally has radiative access to the coldness of the universe. Therefore, in these applications it would be very attractive to directly use the sky as a heat sink while preserving solar absorption properties. Here we experimentally demonstrate a visibly transparent thermal blackbody, based on a silica photonic crystal. When placed on a silicon absorber under sunlight, such a blackbody preserves or even slightly enhances sunlight absorption, but reduces the temperature of the underlying silicon absorber by as much as 13 °C due to radiative cooling. Our work shows that the concept of radiative cooling can be used in combination with the utilization of sunlight, enabling new technological capabilities. PMID:26392542

  6. Optimum dry-cooling sub-systems for a solar air conditioner

    NASA Technical Reports Server (NTRS)

    Chen, J. L. S.; Namkoong, D.

    1978-01-01

    Dry-cooling sub-systems for residential solar powered Rankine compression air conditioners were economically optimized and compared with the cost of a wet cooling tower. Results in terms of yearly incremental busbar cost due to the use of dry-cooling were presented for Philadelphia and Miami. With input data corresponding to local weather, energy rate and capital costs, condenser surface designs and performance, the computerized optimization program yields design specifications of the sub-system which has the lowest annual incremental cost.

  7. Solar heating and cooling system for an office building at Reedy Creek Utilities

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The solar energy system installed in a two story office building at a utilities company, which provides utility service to Walt Disney World, is described. The solar energy system application is 100 percent heating, 80 percent cooling, and 100 percent hot water. The storage medium is water with a capacity of 10,000 gallons hot and 10,000 gallons chilled water. Performance to date has equaled or exceeded design criteria.

  8. Materials-research recommendations to improve the performance and durability of solar heating and cooling systems

    SciTech Connect

    Herzenberg, S.; Silberglitt, R.

    1981-09-11

    The type of materials research most likely to improve the durability and efficiency of future active and passive solar heating and cooling systems is analyzed. Research needs are compared with ongoing solar materials research, and the extent to which present research efforts are addressing the critical flat plate collector needs is assessed. Areas most in need of additional attention are identified. Research recommendations are made for glazing materials, selective absorbers, and heat transfer fluids. (LEW)

  9. Solar heating and cooling system design and development

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Application surveys and performance studies were conducted to determine a solar heating and hot water configuration that could be used in a variety of applications, and to identify subsystem modules that could be utilized in a building block fashion to adapt hardware items to single and multi-family residential and commercial systems. Topics discussed include: subsystem development for the solar collectors, controls, other components, energy management module, and the heating system configuration test. Operational tests conducted at an Illinois farmhouse, and a YWCA in Spokane, Washington are discussed.

  10. Corrosion inhibitors for solar heating and cooling systems

    NASA Technical Reports Server (NTRS)

    Tabony, J. H.

    1978-01-01

    Candidate materials were tested for their ability to limit corrosion under conditions that approximate those found in typical solar-energy system. In addition to presentation of data, report also includes discussion of different forms of corrosion and recommendations for future work.

  11. Corrosion inhibitors for solar heating and cooling systems

    NASA Technical Reports Server (NTRS)

    Humphries, T. S.

    1978-01-01

    Inhibitors which appeared promising in previous tests and additional inhibitors including several proprietary products were evaluated. Evaluation of the inhibitors was based on corrosion protection afforded an aluminum-mild steel-copper-stainless steel assembly in a hot corrosive water. Of the inhibitors tested two were found to be effective and show promise for protecting multimetallic solar heating systems.

  12. Guide to effective solar heating and cooling practice

    SciTech Connect

    Powell, P.C.; Fostel, H.F.; Cody, E.P.

    1981-10-01

    A detaled and systematic inventory of technical experiences at residential and commercial solar demonstration sites across the nation is provided, and design approaches are described which have been shown to dramatically improve system performance. A review has been made of nearly one hundred sites which have been instrumented and feeding data continuously into the National Solar Data Network. It is found that the success of individual systems in meeting or exceeding their design targets depends on effectively controlled design, installation, operation and maintenance. However, numerous reported problems have also been due to poor communication between the various parties involved, and additionally due to failure to identify problems as the develop. Overall, such factors appear to have contributed greatly to the general underperformance seen at the sites. It is found that solar systems must be designed to operate efficiently during periods of minimum as well as peak loads. Solar coth the conversion, distribution, and end use of ethanol are all amenable to control or mitigation through andstone (Kfh), and the Hell Creek formation (Khc). Anomaly No. 31 is over an area underlain by Recent alluvium (Qal).

  13. Flow tube used to cool solar-pumped laser

    NASA Technical Reports Server (NTRS)

    1968-01-01

    A flow tube has been designed and constructed to provide two major functions in the application of a laser beam for transmission of both sound and video. It maintains the YAG laser at the proper operating temperature of 300 degrees K under solar pumping conditions, and it serves as a pump cavity for the laser crystal.

  14. Review of state-of-the-art of solar collector corrosion processes. Task 1 of solar collector studies for solar heating and cooling applications. Final technical progress report

    SciTech Connect

    Clifford, J E; Diegle, R B

    1980-04-11

    The state-of-the-art of solar collector corrosion processes is reviewed, and Task 1 of a current research program on use of aqueous heat transfer fluids for solar heating and cooling is summarized. The review of available published literature has indicated that lack of quantitative information exists relative to collector corrosion at the present time, particularly for the higher temperature applications of solar heating and cooling compared to domestic water heating. Solar collector systems are reviewed from the corrosion/service life viewpoint, with emphasis on various applications, collector design, heat transfer fluids, and freeze protection methods. Available information (mostly qualitative) on collector corrosion technology is reviewed to indicate potential corrosion problem areas and corrosion prevention practices. Sources of limited quantitative data that are reviewed are current solar applications, research programs on collector corrosion, and pertinent experience in related applications of automotive cooling and non-solar heating and cooling. A data bank was developed to catalog corrosion information. Appendix A of this report is a bibliography of the data bank, with abstracts reproduced from presently available literature accessions (about 220). This report is presented as a descriptive summary of information that is contained in the data bank.

  15. How to solve materials and design problems in solar heating and cooling. Energy technology review No. 77

    SciTech Connect

    Ward, D.S.; Oberoi, H.S.; Weinstein, S.D.

    1982-01-01

    A broad range of difficulties encountered in active and passive solar space heating systems and active solar space cooling systems is covered. The problems include design errors, installation mistakes, inadequate durability of materials, unacceptable reliability of components, and wide variations in performance and operation of different solar systems. Feedback from designers and manufacturers involved in the solar market is summarized. The designers' experiences with and criticisms of solar components are presented, followed by the manufacturers' replies to the various problems encountered. Information is presented on the performance and operation of solar heating and cooling systems so as to enable future designs to maximize performance and eliminate costly errors. (LEW)

  16. Cryopreservation of Recalcitrant (i.e. Desiccation-Sensitive) Seeds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    “Recalcitrant” seeds do not survive conventional storage conditions used in genebanks and so must be cryopreserved. Many of the procedures used to cryopreserve recalcitrant seeds balance damage induced by desiccation and freezing stresses, and mitigate the latter through rapid cooling treatments. ...

  17. Handbook of experiences in the design and installation of solar heating and cooling systems

    SciTech Connect

    Ward, D.S.; Oberoi, H.S.

    1980-07-01

    A large array of problems encountered are detailed, including design errors, installation mistakes, cases of inadequate durability of materials and unacceptable reliability of components, and wide variations in the performance and operation of different solar systems. Durability, reliability, and design problems are reviewed for solar collector subsystems, heat transfer fluids, thermal storage, passive solar components, piping/ducting, and reliability/operational problems. The following performance topics are covered: criteria for design and performance analysis, domestic hot water systems, passive space heating systems, active space heating systems, space cooling systems, analysis of systems performance, and performance evaluations. (MHR)

  18. Design, fabrication, testing, and delivery of a solar energy collector system for residential heating and cooling

    NASA Technical Reports Server (NTRS)

    Holland, T. H.; Borzoni, J. T.

    1976-01-01

    A low cost flat plate solar energy collector was designed for the heating and cooling of residential buildings. The system meets specified performance requirements, at the desired system operating levels, for a useful life of 15 to 20 years, at minimum cost and uses state-of-the-art materials and technology. The rationale for the design method was based on identifying possible material candidates for various collector components and then selecting the components which best meet the solar collector design requirements. The criteria used to eliminate certain materials were: performance and durability test results, cost analysis, and prior solar collector fabrication experience.

  19. Design data brochure for the Owens-Illinois Sunpak (TM) air-cooled solar collector

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Information necessary to evaluate the design and installation of the Owens-Illinois Sunpak TM Air-Cooled Solar Collector is presented. Information includes collector features, fluid flow, thermal performance, installation and system tips. The collector utilizes a highly selective wavelength coating in combination with vacuum insulation, which virtually eliminates conduction and convention losses.

  20. Subsystem design package for the on-site monitor at solar heating and cooling sites

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The on-site monitor is a portable device which can be easily connected to a Site Data Acquisition Subsystem to allow readouts of realtime sensor data in voltage or engineering units at instrumented solar heating and cooling sites. The design package consists of the performance specification, performance requirements cross reference, and the acceptance test procedure.

  1. Solar Heating/Cooling of Buildings: Current Building Community Projects. An Interim Report.

    ERIC Educational Resources Information Center

    National Academy of Sciences - National Research Council, Washington, DC. Building Research Advisory Board.

    Projects being carried out by the private sector involving the use of solar energy for heating and cooling buildings are profiled in this report. A substantial portion of the data were collected from a broad cross-section of the building community. Data collection efforts also involved the canvassing of the nearly 200 trade and professional…

  2. Interim Policy Options for Commercialization of Solar Heating and Cooling Systems.

    ERIC Educational Resources Information Center

    Bezdek, Roger

    This interim report reviews the major incentive policy options available to accelerate market penetration of solar heating and cooling (SHAC) systems. Feasible policy options designed to overcome existing barriers to commercial acceptance and market penetration are identified and evaluated. The report is divided into seven sections, each dealing…

  3. National Program for Solar Heating and Cooling of Buildings. Project Data Summaries. Vol. II: Demonstration Support.

    ERIC Educational Resources Information Center

    Energy Research and Development Administration, Washington, DC. Div. of Solar Energy.

    Brief abstracts of projects funded by the Energy Research and Development Administration (ERDA) and conducted under the National Program for Solar Heating and Cooling of Buildings are presented in three volumes. This, the second volume, identifies the major efforts currently underway in support of the national program. The National Aeronautics and…

  4. Solar Heating and Cooling for a Controls Manufacturing Plant Lumberton, New Jersey

    NASA Technical Reports Server (NTRS)

    1982-01-01

    Comprehensive report documents computer-controlled system which has separate solar-collector and cooling-tower areas located away from building and is completely computer controlled. System description, test data, major problems and resolution, performance, operation and maintenance, manufacturer's literature and drawing comprise part of 257-page report.

  5. municipal recreation center is heated and cooled by solar energy

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Major fraction of energy requirements for community building is ksupplied by Sun. The 238 flat plate solar collectors are roof mounted on single story structure enclosing gymnasium, locker area, and health care clinic; heat exchanger transfers collected energy to 6,000 gallon storage tank. Final report chronicles project from inception to completion, documenting performance, costs, operating modes, and data acquisition system. Appendix contains manufacturers' product literature and engineering drawings.

  6. Passive-solar directional-radiating cooling system

    DOEpatents

    Hull, J.R.; Schertz, W.W.

    1985-06-27

    A radiative cooling system for use with an ice-making system having a radiating surface aimed at the sky for radiating energy at one or more wavelength bands for which the atmosphere is transparent and a cover thermally isolated from the radiating surface and transparent at least to the selected wavelength or wavelengths, the thermal isolation reducing the formation of condensation on the radiating surface and/or cover and permitting the radiation to continue when the radiating surface is below the dewpoint of the atmosphere, and a housing supporting the radiating surface, cover and heat transfer means to an ice storage reservoir.

  7. Passive-solar directional-radiating cooling system

    DOEpatents

    Hull, John R.; Schertz, William W.

    1986-01-01

    A radiative cooling system for use with an ice-making system having a radiating surface aimed at the sky for radiating energy at one or more wavelength bands for which the atmosphere is transparent and a cover thermally isolated from the radiating surface and transparent at least to the selected wavelength or wavelengths, the thermal isolation reducing the formation of condensation on the radiating surface and/or cover and permitting the radiation to continue when the radiating surface is below the dewpoint of the atmosphere, and a housing supporting the radiating surface, cover and heat transfer means to an ice storage reservoir.

  8. Passive-solar-cooling system concepts for small office buildings. Final report

    SciTech Connect

    Whiddon, W.I.; Hart, G.K.

    1983-02-01

    This report summarizes the efforts of a small group of building design professionals and energy analysis experts to develop passive solar cooling concepts including first cost estimates for small office buildings. Two design teams were brought together at each of two workshops held in the fall of 1982. Each team included an architect, mechanical engineer, structural engineer, and energy analysis expert. This report presents the passive cooling system concepts resulting from the workshops. It summarizes the design problems, solutions and first-cost estimates relating to each technology considered, and documents the research needs identified by the participants in attempting to implement the various technologies in an actual building design. Each design problem presented at the workshops was based on the reference (base case) small office building analyzed as part of LBL's Cooling Assessment. Chapter II summarizes the thermal performance, physical specifications and estimated first-costs of the base case design developed for this work. Chapters III - VI describe the passive cooling system concepts developed for each technology: beam daylighting; mass with night ventilation; evaporative cooling; and integrated passive cooling systems. The final Chapters, VII and VIII present the preliminary implications for economics of passive cooling technologies (based on review of the design concepts) and recommendations of workshop participants for future research in passive cooling for commercial buildings. Appendices provide backup information on each chapter as indicated.

  9. Influence of Ventilation Ratio on Desiccant Air Conditioning System's Efficiency Performance

    NASA Astrophysics Data System (ADS)

    Tran, Thien Nha; Akisawa, Atsushi; Kashiwagi, Takao; Hamamoto, Yoshinori

    Ventilation air is a concern for engineers since ventilated air controls indoor air contamination; additional ventilation, however, increases the energy consumption of buildings. The study investigates the energy efficiency performance of the desiccant dehumidification air conditioning system in the context of ventilation for a hot-humid climate such as summer in Japan. The investigation focuses on the variable ratio of ventilation air as required by the application of air conditioning system. The COP of the desiccant air conditioning system is determined. The evaluation is subsequently performed by comparing the desiccant based system with the conventional absorption cooling system and the vapor compression cooling system. Based on 12 desiccant rotor simulations, it is found that the desiccant regeneration temperature required varies between 47°C to 85°C as ventilation ratio increases from 0. 0 to 100%, and up to 52. 5°C as the ventilation ratio achieves 14%. The heat required for regenerating desiccant accounts for 55% and higher of the system's total heat consumption; the system is expected to be energy efficient by using wasted heat from the absorption chiller for desiccant regeneration; and its energy efficiency expands as the ratio of ventilation air rises above 15% compared with the conventional absorption cooling system. The energy efficiency also benefits as the ratio rises beyond 70% against the conventional vapor compression cooling system.

  10. Solar heating and cooling system installed at Leavenworth, Kansas. Final report

    SciTech Connect

    Perkins, R. M.

    1980-06-01

    The solar heating and cooling system installed at the headquarters of Citizens Mutual Savings Association in Leavenworth, Kansas, is described in detail. The project is part of the U.S. Department of Energy's solar demonstration program and became operational in March, 1979. The designer was TEC, Inc. Consulting Engineers, Kansas City, Missouri and contractor was Norris Brothers, Inc., Lawrence, Kansas. The solar system is expected to furnish 90 percent of the overall heating load, 70 percent of the cooling load and 100 percent of the domestic hot water load. The building has two floors with a total of 12,000 square feet gross area. The system has 120 flat-plate liquid solar panels with a net area of 2200 square feet. Five, 3-ton Arkla solar assisted absorption units provide the cooling, in conjunction with a 3000 gallon chilled water storage tank. Two, 3000 gallon storage tanks are provided with one designated for summer use, whereas both tanks are utilized during winter.

  11. Summary of NASA Lewis Research Center solar heating and cooling and wind energy programs

    NASA Technical Reports Server (NTRS)

    Vernon, R. W.

    1975-01-01

    Plans for the construction and operation of a solar heating and cooling system in conjunction with a office building being constructed at Langley Research Center, are discussed. Supporting research and technology includes: testing of solar collectors with a solar simulator, outdoor testing of collectors, property measurements of selective and nonselective coatings for solar collectors, and a solar model-systems test loop. The areas of a wind energy program that are being conducted include: design and operation of a 100-kW experimental wind generator, industry-designed and user-operated wind generators in the range of 50 to 3000 kW, and supporting research and technology for large wind energy systems. An overview of these activities is provided.

  12. Modelling the solar irradiance during the Maunder Minimum and the corresponding cooling

    SciTech Connect

    Garduno, R.; Mendoza, B.; Adem, J.

    1996-12-31

    Expressions to compute the solar irradiance as a function of the sun rotation rate, sunspot number and solar cycle length, are deduced. They yield a solar irradiance dimmed by about 0.5% during the Maunder Minimum (1660-1720). This parameter is put in the Adem thermodynamic model as an external forcing to simulate the corresponding climate change. Another forcing used is the preindustrial level of atmospheric CO{sub 2} which reinforces the cooling. The model generates three internal feedbacks: cryosphere, cloudiness and water vapor. The output is a cooling of about 0.5 to 1 C, with respect to present climate, depending on the forcings and feedbacks included. These results agree well with those from other authors and with the few historical records.

  13. Analysis of a solar heat pipe heating and absorption cooling system

    NASA Astrophysics Data System (ADS)

    Munje, S. R.

    A new concept which combines a flat-plate heat-pipe solar collector for daytime solar water heating by evaporation of a refrigerant and night-time water chilling by absorption refrigeration was analyzed. A comprehensive survey of literature was completed to establish the existing state of knowledge on intermittent absorption refrigeration, flat-plate solar heat collectors and night sky radiation cooling. The literature survey showed that the idea of using a passive device such as a heat pipe with the absorption refrigeration principle for both heating and cooling is relatively new. A mathematical model for the heat-pipe flat-plate collector and the absorption refrigeration process was developed. A cost-effectiveness study was also carried out to find the optimum thickness of the collector plate. The optimum plate thickness was used in the parametric study of the system.

  14. Solar Heating And Cooling (SHAC) simulation programs: Assessment and evaluation. Volume 1: Summary report

    NASA Astrophysics Data System (ADS)

    Merriam, R. L.

    1981-05-01

    Solar heating and cooling system simulation programs available to use by electric utilities was evaluated. A comprehensive reference manual describing the characteristics of computer programs and manual methods was developed. An analysis of the intended capabilities of 11 programs is carried out. The programs are described and ranked by application. Four programs (AXCESS, DEROB, EMPSS, TRNSYS) for three building types (residential, light commercial, and heavy commercial) and three heating and cooling system classes (conventional, active solar, passive solar are tested. The results are compared and related to the program analytical bases. The user experience encountered during the program testing is highlighted and the user related factors for the four programs are compared. The applicability of the 11 programs to utilities is explored. DOE

  15. Natural/passive solar heating and cooling for poultry sheds

    SciTech Connect

    Abd El-Salam, E.M.

    1980-12-01

    Arid climates, as in Egypt and the Middle-East regions, are characterized by large durinal and seasonal temperature variation coupled with clear skies and ample sunshine duration. Partial stabilization of indoor thermal environment in habitation is of great comfort for human and have large effects on animals or birds productivities. In case of poultry or animal sheds, can have some economical turn over in terms of increased egg or animal productivity and reduction of mortality rates if their indoor thermal environment is favorably controlled. Poultry birds are sensitive to changes of ambient temperatures, humidity and other environmental variables. This investigation describes an unconventional method of maintaining moderate thermal environment within poultry sheds by using the roof for storage of heat and coolness in appropriate seasons. During winter, underground water is circulated through specially designed pipe matrix imbeded in the roof slab and through radiant wall panels.

  16. Supply problems in the solar heating and cooling industry. Final report

    SciTech Connect

    Not Available

    1981-08-01

    Future distribution channels and costs in the solar-heating-and-cooling industry are discussed and some of the external factors influencing the industry are examined such as public policy initiatives and competing technologies. The distribution channels through which solar equipment passes from manufacturer to consumer are examined; future industry evolution will most likely be towards a multiplicity of distribution networks, each serving a different market segment. The components of solar costs, including collector, other system components, indirect and marketing, and installation and O and M costs, are also reviewed. Costs for high quality solar collectors are projected to increase, however the rate of increase is uncertain. Solar costs could increase at: (a) construction industry cost escalation rates; (b) general economic inflation rates; or (c) lower than the general inflation rate. Nevertheless, the average price paid by consumers is expected to increase at slightly less than the rate of inflation because lower-quality, low-priced systems are expected to garner a larger share of future solar sales. Pertinent public policy initiatives are reviewed which may critically influence the development of solar energy, and the impact of competing energy sources on solar heating economics is considered. Consideration of the projections for the aforementioned supply characteristics suggests that product supply may have a significant constraining influence on the growth of the solar industry.

  17. Economical solar-heating or cooling system with new solar-energy concentrators

    NASA Technical Reports Server (NTRS)

    Shimada, K.

    1975-01-01

    Economical solar energy collector, made from array of cylindrical Fresnel lenses, does not require tracking mechanism. As the sun changes position, lenses focus solar energy on different collector elements.

  18. Use of PCM Boards for Solar Cell Cooling

    NASA Astrophysics Data System (ADS)

    Zmeškal, O.; Štefková, P.; Dohnalová, L.; Bařinka, R.

    2013-05-01

    This contribution explains the use of fractal theory to describe thermal properties of materials. The basic idea is rooted in the theory of fractal fields defined in E-dimensional Euclidian space. Generic equations describing heat distribution are then specialized to describe the changes in heat transfer as a response to step-wise increases in the amount of heat added to the system. This model was then applied to the study of properties of a systems consisting of solar cells attached on a phase-change material (PCM) back sheet board. The aim of this study is to evaluate the ability of PCM boards to decrease the working temperature of solar cells and thus to increase the efficiency of the cells. Regression of experimental data was used to obtain model parameters. The parameters obtained this way were the thermal diffusivity, thermal conductivity, and specific heat, as well as parameters of the heat source and parameters related to the heat losses of the system. The method was then verified against parameters of the system based on poly-methyl-methacrylate and then applied to a PCM with a phase-change temperature of 25 °C. The values of the thermal parameters were determined at temperatures where both components of the PCM composite (Micronal® and gypsum wall) were solid and below the phase-change temperature and then again at temperatures where one of the components (gypsum) was still solid, while the other one was already liquid (wax). The attempt to determine the parameters during the phase change was not made due the physicochemical processes taking place which would alter the measured data.

  19. Direct observations of plasma upflows and condensation in a catastrophically cooling solar transition region loop

    SciTech Connect

    Orange, N. B.; Chesny, D. L.; Oluseyi, H. M.; Hesterly, K.; Patel, M.; Champey, P.

    2013-12-01

    Minimal observational evidence exists for fast transition region (TR) upflows in the presence of cool loops. Observations of such occurrences challenge notions of standard solar atmospheric heating models as well as their description of bright TR emission. Using the EUV Imaging Spectrometer on board Hinode, we observe fast upflows (v {sub λ} ≤ –10 km s{sup –1}) over multiple TR temperatures (5.8 ≤log T ≤ 6.0) at the footpoint sites of a cool loop (log T ≤ 6.0). Prior to cool loop energizing, asymmetric flows of +5 km s{sup –1} and –60 km s{sup –1} are observed at footpoint sites. These flows, speeds, and patterns occur simultaneously with both magnetic flux cancellation (at the site of upflows only) derived from the Solar Dynamics Observatory's Helioseismic Magnetic Imager's line-of-sight magnetogram images, and a 30% mass influx at coronal heights. The incurred non-equilibrium structure of the cool loop leads to a catastrophic cooling event, with subsequent plasma evaporation indicating that the TR is the heating site. From the magnetic flux evolution, we conclude that magnetic reconnection between the footpoint and background field is responsible for the observed fast TR plasma upflows.

  20. Measurement uncertainty of adsorption testing of desiccant materials

    SciTech Connect

    Bingham, C E; Pesaran, A A

    1988-12-01

    The technique of measurement uncertainty analysis as described in the current ANSI/ASME standard is applied to the testing of desiccant materials in SERI`s Sorption Test Facility. This paper estimates the elemental precision and systematic errors in these tests and propagates them separately to obtain the resulting uncertainty of the test parameters, including relative humidity ({plus_minus}.03) and sorption capacity ({plus_minus}.002 g/g). Errors generated by instrument calibration, data acquisition, and data reduction are considered. Measurement parameters that would improve the uncertainty of the results are identified. Using the uncertainty in the moisture capacity of a desiccant, the design engineer can estimate the uncertainty in performance of a dehumidifier for desiccant cooling systems with confidence. 6 refs., 2 figs., 8 tabs.

  1. Desiccant outdoor air preconditioners maximize heat recovery ventilation potentials

    SciTech Connect

    Meckler, M.

    1995-12-31

    Microorganisms are well protected indoors by the moisture surrounding them if the relative humidity is above 70%. They can cause many acute diseases, infections, and allergies. Humidity also has an effect on air cleanliness and causes the building structure and its contents to deteriorate. Therefore, controlling humidity is a very important factor to human health and comfort and the structural longevity of a building. To date, a great deal of research has been done, and is continuing, in the use of both solid and liquid desiccants. This paper introduces a desiccant-assisted system that combines dehumidification and mechanical refrigeration by means of a desiccant preconditioning module that can serve two or more conventional air-conditioning units. It will be demonstrated that the proposed system, also having indirect evaporative cooling within the preconditioning module, can reduce energy consumption and provide significant cost savings, independent humidity and temperature control, and, therefore, improved indoor air quality and enhanced occupant comfort.

  2. Effect of solar radiation on the performance of cross flow wet cooling tower in hot climate of Iran

    NASA Astrophysics Data System (ADS)

    Banooni, Salem; Chitsazan, Ali

    2016-01-01

    In some cities such as Ahvaz-Iran, the solar radiation is very high and the annual-mean-daily of the global solar radiation is about 17.33 MJ m2 d-1. Solar radiation as an external heat source seems to affect the thermal performance of the cooling towers. Usually, in modeling cooling tower, the effects of solar radiation are ignored. To investigate the effect of sunshade on the performance and modeling of the cooling tower, the experiments were conducted in two different states, cooling towers with and without sunshade. In this study, the Merkel's approach and finite difference technique are used to predict the thermal behavior of cross flow wet cooling tower without sunshade and the results are compared with the data obtained from the cooling towers with and without sunshade. Results showed that the sunshade is very efficient and it reduced the outlet water temperature, the approach and the water exergy of the cooling tower up to 1.2 °C, 15 and 1.1 %, respectively and increased the range and the efficiency of the cooling tower up to 29 and 37 %, respectively. Also, the sunshade decreased the error between the experimental data of the cooling tower with sunshade and the modeling results of the cooling tower without sunshade 1.85 % in average.

  3. Solar heating and cooling of residential buildings: design of systems, 1980 edition

    SciTech Connect

    1980-09-01

    This manual was prepared primarily for use in conducting a practical training course on the design of solar heating and cooling systems for residential and small office buildings, but may also be useful as a general reference text. The content level is appropriate for persons with different and varied backgrounds, although it is assumed that readers possess a basic understanding of heating, ventilating, and air-conditioning systems of conventional (non-solar) types. This edition is a revision of the manual with the same title, first printed and distributed by the US Government Printing Office in October 1977. The manual has been reorganized, new material has been added, and outdated information has been deleted. Only active solar systems are described. Liquid and air-heating solar systems for combined space and service water heating or service water heating are included. Furthermore, only systems with proven experience are discussed to any extent.

  4. Review of open-cycle desiccant air-conditioning concepts and systems

    SciTech Connect

    Wurm, J.

    1986-08-01

    This paper attempts to overview the development status of desiccant cooling. Over the past 30 years of progressively intensifying attention, this promising technology has become a domain of interest of many research agencies and manufacturing companies. As a result, the market potential for machines based on desiccant processes, particularly in comfort cooling and agricultural applications, is getting close to realization. One of the most important incentives of developing heat-activated, open-cycle desiccant cooling machines (air conditioners) has always been its potential simplicity. Such premise has been deceiving to a degree that in many instances has slowed the progress. However, the persistent analytical and material research brought some desiccant systems close to the marketplace. They provide attractive alternatives to consumers and utilities, offering particularly effective humidity and temperature control in cases of high fresh-air-makeup requirements. The control of bacteria, airborne particulates, as well as CO/sub 2/, combined with effective heating capability make them attractive for controlled-atmosphere agriculture. Finally, the capability of using low-temperature waste heat to drive the cycle becomes an important attribute of a desiccant concept, specifically when combined with a regular vapor-compression cooling machine in energy saving space-conditioning concepts. The presented assessment concludes that, particularly for specialized applications, machines based on open-cycle desiccant cooling processes are very close to playing an important role in the space-conditioning (including comfort control) marketplace.

  5. Analysis of data user's needs for performance evaluation of solar heating and cooling systems

    NASA Technical Reports Server (NTRS)

    Christensen, D. L.

    1978-01-01

    In a successful data acquisition program, the information needs must be evaluated, the design and cost factors of the program must be determined, and a data management loop must be organized and operated in order to collect, process, and disseminate the needed information in useable formats. This paper describes each of these program elements in detail as an aid for the solar heating and cooling data manager and user to implement effective data acquisition and monitoring systems. Consideration is given to the development of evaluation techniques which will aid in the determination of solar energy systems performances.

  6. Temperature distribution of a hot water storage tank in a simulated solar heating and cooling system

    NASA Technical Reports Server (NTRS)

    Namkoong, D.

    1976-01-01

    A 2,300-liter hot water storage tank was studied under conditions simulating a solar heating and cooling system. The initial condition of the tank, ranging from 37 C at the bottom to 94 C at the top, represented a condition midway through the start-up period of the system. During the five-day test period, the water in the tank gradually rose in temperature but in a manner that diminished its temperature stratification. Stratification was found not to be an important factor in the operation of the particular solar system studied.

  7. Solar heating and cooling system installed at Columbus, Ohio. Final report

    SciTech Connect

    Coy, R. G.; Braden, R. P.

    1980-09-01

    The Solar Energy System installed at Columbus Technical Institute, Columbus, Ohio was installed as a part of a new construction of a college building. The building will house classrooms and laboratories, administrative offices and three lecture halls. The Solar Energy System consists of 4096 square feet (128 panels) Owens/Illinois Evacuated Glass Tube Collector Subsystem, and a 5000 gallon steel tank below ground storage system, hot water is circulated between the collectors and storage tank, passing through a water/lithium bromide absorption chiller to cool the building. Extracts from the site files specification references, drawings, installation, operation and maintenance instructions are included.

  8. What are the relative roles of heating and cooling in generating solar wind temperature anisotropies?

    PubMed

    Maruca, B A; Kasper, J C; Bale, S D

    2011-11-11

    Temperature anisotropy in the solar wind results from a combination of mechanisms of anisotropic heating (e.g., cyclotron-resonant heating and dissipation of kinetic Alfvén waves) and cooling (e.g., Chew-Goldberger-Low double-adiabatic expansion). In contrast, anisotropy-driven instabilities such as the cyclotron, mirror, and firehose instabilities limit the allowable departure of the plasma from isotropy. This study used data from the Faraday cups on the Wind spacecraft to examine scalar temperature and temperature components of protons. Plasma unstable to the mirror or firehose instability was found to be about 3-4 times hotter than stable plasma. Since anisotropy-driven instabilities are not understood to heat the plasma, these results suggest that heating processes are more effective than cooling processes at creating and maintaining proton temperature anisotropy in the solar wind. PMID:22181718

  9. Performance criteria for solar heating and cooling systems in residential buildings

    NASA Astrophysics Data System (ADS)

    1982-09-01

    This performance criteria, developed for the Department of Housing and Urban Development, is a baseline document for criteria and standards for the design, development, technical evaluation, and procurement of solar heating and cooling systems for residential buildings in accordance with the requirements of Section 8 of Public Law 93-409, the Solar Heating and Cooling Demonstration Act of 1974. The document is intended to establish minimum levels of performance with regard to health and safety and the various aspects of technical performance. The criteria for health and safety put primary emphasis on compliance with existing codes and standards. The criteria on thermal and mechanical performance, durability/reliability and operation/servicing present performance requirements considered to be representative of acceptable levels.

  10. Review of Desiccant Dehumidification Technology

    SciTech Connect

    Pesaran, A. A.

    1994-10-01

    This paper overviews applications of desiccant technology for dehumidifying commercial and institutional buildings. Because of various market, policy, and regulatory factors, this technology is especially attractive for dehumidification applications in the I990s.

  11. Summary of NASA-Lewis Research Center solar heating and cooling and wind energy programs

    NASA Technical Reports Server (NTRS)

    Vernon, R. W.

    1975-01-01

    NASA is planning to construct and operate a solar heating and cooling system in conjunction with a new office building being constructed at Langley Research Center. The technology support for this project will be provided by a solar energy program underway at NASA's Lewis Research Center. The solar program at Lewis includes: testing of solar collectors with a solar simulator, outdoor testing of collectors, property measurements of selective and nonselective coatings for solar collectors, and a solar model-systems test loop. NASA-Lewis has been assisting the National Science Foundation and now the Energy Research and Development Administration in planning and executing a national wind energy program. The areas of the wind energy program that are being conducted by Lewis include: design and operation of a 100 kW experimental wind generator, industry-designed and user-operated wind generators in the range of 50 to 3000 kW, and supporting research and technology for large wind energy systems. An overview of these activities is provided.

  12. Observations and Modeling of the Pulse-driven Cool Plasma Ejecta in the Solar Atmosphere

    NASA Astrophysics Data System (ADS)

    Srivastava, Abhishek K.; Murawski, . Kris; Kayshap, Pradeep

    2012-07-01

    The cool plasma ejecta are ubiquitous in the solar atmosphere, and have significant implications on its mass and energy transport. We present two case studies of the SDO/AIA observations of (i) cool jet at north polar region, and (ii) the cool surge ejecta at the active region boundary. The common nature between these two different class of plasma dynamics is that both do not reveal any signature of strong heating during course of their life-times. The surge shows some evidence of heating at its footpoint, however, mostly not visible in the SDO/AIA filters sensitive to the higher coronal temperatures. Similarly, the polar jet is also only evident in the SDO/AIA 304 Å channel that is sensitive to the plasma maintained around 0.1 MK, and does not show any signature of heating. We model these cool jets by launching reconnection generated pulses in the VAL-III C model of the solar temperature as an initial condition. For the case of cool polar jet, we launch reconnection generated velocity pulse in the more realistic solar atmosphere, which steepens into a shock at higher altitudes and triggers plasma perturbations exhibiting the observed features of the jet. However, the footpoint of the surge shows small heating episode in the second case study, therefore, we consider the excitation of reconnection generated thermal pulse which triggers plasma perturbations approximately exhibiting the observed features of the surge, e.g., average velocity, height, width, life-time, and fine structures at its base. We also compare our new results with the existing models and observations of such jets, and plasma flows especially reported in the SDO era.

  13. System design and installation for RS600 programmable control system for solar heating and cooling

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Procedures for installing, operating, and maintaining a programmable control system which utilizes a F8 microprocessor to perform all timing, control, and calculation functions in order to customize system performance to meet individual requirements for solar heating, combined heating and cooling, and/or hot water systems are described. The manual discusses user configuration and options, displays, theory of operation, trouble-shooting procedures, and warranty and assistance. Wiring lists, parts lists, drawings, and diagrams are included.

  14. Preliminary design review package for the solar heating and cooling central data processing system

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The Central Data Processing System (CDPS) is designed to transform the raw data collected at remote sites into performance evaluation information for assessing the performance of solar heating and cooling systems. Software requirements for the CDPS are described. The programming standards to be used in development, documentation, and maintenance of the software are discussed along with the CDPS operations approach in support of daily data collection and processing.

  15. Evidence for Solar Cycle Influence on the Infrared Energy Budget and Radiative Cooling of the Thermosphere

    NASA Technical Reports Server (NTRS)

    Mlynczak, Martin G.; Martin-Torres, F. Javier; Marshall, B. Thomas; Thompson, R. Earl; Williams, Joshua; Turpin, TImothy; Kratz, D. P.; Russell, James M.; Woods, Tom; Gordley, Larry L.

    2007-01-01

    We present direct observational evidence for solar cycle influence on the infrared energy budget and radiative cooling of the thermosphere. By analyzing nearly five years of data from the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument, we show that the annual mean infrared power radiated by the nitric oxide (NO) molecule at 5.3 m has decreased by a factor of 2.9. This decrease is correlated (r = 0.96) with the decrease in the annual mean F10.7 solar index. Despite the sharp decrease in radiated power (which is equivalent to a decrease in the vertical integrated radiative cooling rate), the variability of the power as given in the standard deviation of the annual means remains approximately constant. A simple relationship is shown to exist between the infrared power radiated by NO and the F10.7 index, thus providing a fundamental relationship between solar activity and the thermospheric cooling rate for use in thermospheric models. The change in NO radiated power is also consistent with changes in absorbed ultraviolet radiation over the same time period.

  16. The design of a solar energy collection system to augment heating and cooling for a commercial office building

    NASA Technical Reports Server (NTRS)

    Basford, R. C.

    1977-01-01

    Analytical studies supported by experimental testing indicate that solar energy can be utilized to heat and cool commercial buildings. In a 50,000 square foot one-story office building at the Langley Research Center, 15,000 square feet of solar collectors are designed to provide the energy required to supply 79 percent of the building heating needs and 52 percent of its cooling needs. The experience gained from the space program is providing the technology base for this project. Included are some of the analytical studies made to make the building design changes necessary to utilize solar energy, the basic solar collector design, collector efficiencies, and the integrated system design.

  17. Development and testing of thermal-energy-storage modules for use in active solar heating and cooling systems. Final report

    SciTech Connect

    Parker, J.C.

    1981-04-01

    Additional development work on thermal-energy-storage modules for use with active solar heating and cooling systems is summarized. Performance testing, problems, and recommendations are discussed. Installation, operation, and maintenance instructions are included. (MHR)

  18. Solar Heating and Cooling Demonstration Project at Radian Corporation, Austin, Texas. Final report

    SciTech Connect

    Not Available

    1980-05-01

    This document is the final technical report of the solar energy facility located at the Radian Corporation, Austin, Texas, 78766. This system has been operational since April 1977. Major components of this system include 36 Northrup collectors, a 1500 gallon fiberglass thermal storage tank, an ARKLA absorption cooling unit and cooling tower, a Servel heating coil, pumps, heat exchanger, and a conventional backup heating and air conditioning unit. System controls consist of a dual-stage thermostat, a control panel, a differential temperature controller, and three absolute temperature controllers. The system is designed to operate in several modes with evaluation of each mode. System performance monitoring is accomplished through 47 sensors which are sampled and recorded every five minutes by a data acquisition system. An on-site-monitor test set allows instantaneous testing and evaluation. This report also references Monthly Performance Reports, a Solar Energy System Performance Evaluation Report, a Solar Project Cost Report and a Solar Project Description Report for this site which are available through the National Technical Information Service.

  19. Transient analysis and energy optimization of solar heating and cooling systems in various configurations

    SciTech Connect

    Calise, F.; Dentice d'Accadia, M.; Palombo, A.

    2010-03-15

    In this paper, a transient simulation model of solar-assisted heating and cooling systems (SHC) is presented. A detailed case study is also discussed, in which three different configurations are considered. In all cases, the SHC system is based on the coupling of evacuated solar collectors with a single-stage LiBr-H{sub 2}O absorption chiller, and a gas-fired boiler is also included for auxiliary heating, only during the winter season. In the first configuration, the cooling capacity of the absorption chiller and the solar collector area are designed on the basis of the maximum cooling load, and an electric chiller is used as the auxiliary cooling system. The second layout is similar to the first one, but, in this case, the absorption chiller and the solar collector area are sized in order to balance only a fraction of the maximum cooling load. Finally, in the third configuration, there is no electric chiller, and the auxiliary gas-fired boiler is also used in summer to feed the absorption chiller, in case of scarce solar irradiation. The simulation model was developed using the TRNSYS software, and included the analysis of the dynamic behaviour of the building in which the SHC systems were supposed to be installed. The building was simulated using a single-lumped capacitance model. An economic model was also developed, in order to assess the operating and capital costs of the systems under analysis. Furthermore, a mixed heuristic-deterministic optimization algorithm was implemented, in order to determine the set of the synthesis/design variables that maximize the energy efficiency of each configuration under analysis. The results of the case study were analyzed on monthly and weekly basis, paying special attention to the energy and monetary flows of the standard and optimized configurations. The results are encouraging as for the potential of energy saving. On the contrary, the SHC systems appear still far from the economic profitability: however, this is

  20. The absorption chiller in large scale solar pond cooling design with condenser heat rejection in the upper convecting zone

    SciTech Connect

    Tsilingiris, P.T. )

    1992-07-01

    The possibility of using solar ponds as low-cost solar collectors combined with commercial absorption chillers in large scale solar cooling design is investigated. The analysis is based on the combination of a steady-state solar pond mathematical model with the operational characteristics of a commercial absorption chiller, assuming condenser heat rejection in the upper convecting zone (U.C.Z.). The numerical solution of the nonlinear equations involved leads to results which relate the chiller capacity with pond design and environmental parameters, which are also employed for the investigation of the optimum pond size for a minimum capital cost. The derived cost per cooling kW for a 350 kW chiller ranges from about 300 to 500 $/kW cooling. This is almost an order of magnitude lower than using a solar collector field of evacuated tube type.

  1. Solar heating and cooling R and D program coordination support. Final report, October 1, 1980-September 30, 1983

    SciTech Connect

    Not Available

    1984-01-01

    The objective of the project was to support the US Department of Energy's international R and D activities in the solar heating and cooling area. The cooperative programs were of two types: bilateral (involving the US and one other country) and multilateral (involving the US and several other countries). The multilateral programs supported under this contract were: International Energy Agency Solar Heating and Cooling Program; and NATO/CCMS Solar Energy Pilot Study. Solar heating and cooling projects under the following bilateral programs were supported: US/Mexico; US/Israel; and US/Spain. The assistance to DOE's Office of Solar Heat Technologies, consisted primarily of program management and coordination support, plus a smaller amount of technical support. This final report summarizes the work performed during the three years of this contract and the accomplishments.

  2. National Program for Solar Heating and Cooling of Buildings. Project Date Summaries. Vol. I: Commercial and Residential Demonstrations.

    ERIC Educational Resources Information Center

    Energy Research and Development Administration, Washington, DC. Div. of Solar Energy.

    Three volumes present brief abstracts of projects funded by the Energy Research and Development Administration (ERDA) and conducted under the National Program for Solar Heating and Cooling of Buildings through July 1976. The overall federal program includes demonstrations of heating and/or combined cooling for residential and commercial buildings…

  3. Passive cooling with solar updraft and evaporative downdraft chimneys. Interim report, June 15, 1984--March 1, 1985

    SciTech Connect

    Mignon, G.V.; Cunningham, W.A.; Thompson, T.L.

    1985-12-31

    Computer models have been developed to describe the operation of both solar updraft and evaporative downdraft chimneys. Design studies are being conducted at the present time to use the towers for cooling an experimental, well instrumented, structure to study passive cooling in residential buildings. (MHR)

  4. Low-Flow Liquid Desiccant Air Conditioning: General Guidance and Site Considerations

    SciTech Connect

    Kozubal, E.; Herrmann, L.; Deru, M.; Clark, J.

    2014-09-01

    Dehumidification or latent cooling in buildings is an area of growing interest that has been identified as needing more research and improved technologies for higher performance. Heating, ventilating, and air-conditioning (HVAC) systems typically expend excessive energy by using overcool-and-reheat strategies to dehumidify buildings. These systems first overcool ventilation air to remove moisture and then reheat the air to meet comfort requirements. Another common strategy incorporates solid desiccant rotors that remove moisture from the air more efficiently; however, these systems increase fan energy consumption because of the high airside pressure drop of solid desiccant rotors and can add heat of absorption to the ventilation air. Alternatively, liquid desiccant air-conditioning (LDAC) technology provides an innovative dehumidification solution that: (1) eliminates the need for overcooling and reheating from traditional cooling systems; and (2) avoids the increased fan energy and air heating from solid desiccant rotor systems.

  5. Investigation of Absorption Cooling Application Powered by Solar Energy in the South Coast Region of Turkey

    NASA Astrophysics Data System (ADS)

    Babayigit, O.; Aksoy, M. H.; Ozgoren, M.; Solmaz, O.

    2013-04-01

    In this study, an absorption system using ammonia-water (NH3-H2O) solution has been theoretically examined in order to meet the cooling need of a detached building having 150 m2 floor area for Antalya, Mersin and Mugla provinces in Turkey. Hourly dynamic cooling load capacities of the building were determined by using Radiant Time Series (RTS) method in the chosen cities. For the analysis, hourly average meteorological data such as atmospheric air temperature and solar radiation belonging to the years 1998-2008 are used for performance prediction of the proposed system. Thermodynamic relations for each component of absorption cooling system is explained and coefficients of performance of the system are calculated. The maximum daily total radiation data were calculated as 7173 W/m2day on July 15, 7277 W/m2 day on July 19 and 7231 W/m2day on July 19 for Mersin, Antalya and Mugla, respectively on the 23° toward to south oriented panels from horizontal surface. The generator operating temperatures are considered between 90-130°C and the best result for 110°C is found the optimum degree for maximum coefficient of performance (COP) values at the highest solar radiation occurred time during the considered days for each province. The COP values varies between 0.521 and 0.530 for the provinces. In addition, absorber and condenser capacities and thermal efficiency for the absorption cooling system were calculated. The necessary evacuated tube collector area for the different provinces were found in the range of 45 m2 to 47 m2. It is shown that although the initial investment cost is higher for the proposed absorption cooling system, it is economically feasible because of its lower annual operation costs and can successfully be operated for the considered provinces.

  6. Desiccant-Based Preconditioning Market Analysis

    SciTech Connect

    Fischer, J.

    2001-01-11

    A number of important conclusions can be drawn as a result of this broad, first-phase market evaluation. The more important conclusions include the following: (1) A very significant market opportunity will exist for specialized outdoor air-handling units (SOAHUs) as more construction and renovation projects are designed to incorporate the recommendations made by the ASHRAE 62-1989 standard. Based on this investigation, the total potential market is currently $725,000,000 annually (see Table 6, Sect. 3). Based on the market evaluations completed, it is estimated that approximately $398,000,000 (55%) of this total market could be served by DBC systems if they were made cost-effective through mass production. Approximately $306,000,000 (42%) of the total can be served by a non-regenerated, desiccant-based total recovery approach, based on the information provided by this investigation. Approximately $92,000,000 (13%) can be served by a regenerated desiccant-based cooling approach (see Table 7, Sect. 3). (2) A projection of the market selling price of various desiccant-based SOAHU systems was prepared using prices provided by Trane for central-station, air-handling modules currently manufactured. The wheel-component pricing was added to these components by SEMCO. This resulted in projected pricing for these systems that is significantly less than that currently offered by custom suppliers (see Table 4, Sect. 2). Estimated payback periods for all SOAHU approaches were quite short when compared with conventional over-cooling and reheat systems. Actual paybacks may vary significantly depending on site-specific considerations. (3) In comparing cost vs benefit of each SOAHU approach, it is critical that the total system design be evaluated. For example, the cost premium of a DBC system is very significant when compared to a conventional air handling system, yet the reduced chiller, boiler, cooling tower, and other expense often equals or exceeds this premium, resulting in a

  7. Recommended requirements to code officials for solar heating, cooling, and hot water systems. Model document for code officials on solar heating and cooling of buildings

    SciTech Connect

    1980-06-01

    These recommended requirements include provisions for electrical, building, mechanical, and plumbing installations for active and passive solar energy systems used for space or process heating and cooling, and domestic water heating. The provisions in these recommended requirements are intended to be used in conjunction with the existing building codes in each jurisdiction. Where a solar relevant provision is adequately covered in an existing model code, the section is referenced in the Appendix. Where a provision has been drafted because there is no counterpart in the existing model code, it is found in the body of these recommended requirements. Commentaries are included in the text explaining the coverage and intent of present model code requirements and suggesting alternatives that may, at the discretion of the building official, be considered as providing reasonable protection to the public health and safety. Also included is an Appendix which is divided into a model code cross reference section and a reference standards section. The model code cross references are a compilation of the sections in the text and their equivalent requirements in the applicable model codes. (MHR)

  8. A solar thermal cooling and heating system for a building: Experimental and model based performance analysis and design

    SciTech Connect

    Qu, Ming; Yin, Hongxi; Archer, David H.

    2010-02-15

    A solar thermal cooling and heating system at Carnegie Mellon University was studied through its design, installation, modeling, and evaluation to deal with the question of how solar energy might most effectively be used in supplying energy for the operation of a building. This solar cooling and heating system incorporates 52 m{sup 2} of linear parabolic trough solar collectors; a 16 kW double effect, water-lithium bromide (LiBr) absorption chiller, and a heat recovery heat exchanger with their circulation pumps and control valves. It generates chilled and heated water, dependent on the season, for space cooling and heating. This system is the smallest high temperature solar cooling system in the world. Till now, only this system of the kind has been successfully operated for more than one year. Performance of the system has been tested and the measured data were used to verify system performance models developed in the TRaNsient SYstem Simulation program (TRNSYS). On the basis of the installed solar system, base case performance models were programmed; and then they were modified and extended to investigate measures for improving system performance. The measures included changes in the area and orientation of the solar collectors, the inclusion of thermal storage in the system, changes in the pipe diameter and length, and various system operational control strategies. It was found that this solar thermal system could potentially supply 39% of cooling and 20% of heating energy for this building space in Pittsburgh, PA, if it included a properly sized storage tank and short, low diameter connecting pipes. Guidelines for the design and operation of an efficient and effective solar cooling and heating system for a given building space have been provided. (author)

  9. Advanced phase change materials and systems for solar passive heating and cooling of residential buildings

    SciTech Connect

    Salyer, I.O.; Sircar, A.K.; Dantiki, S.

    1988-01-01

    During the last three years under the sponsorship of the DOE Solar Passive Division, the University of Dayton Research Institute (UDRI) has investigated four phase change material (PCM) systems for utility in thermal energy storage for solar passive heating and cooling applications. From this research on the basis of cost, performance, containment, and environmental acceptability, we have selected as our current and most promising series of candidate phase change materials, C-15 to C-24 linear crystalline alkyl hydrocarbons. The major part of the research during this contract period was directed toward the following three objectives. Find, test, and develop low-cost effective phase change materials (PCM) that melt and freeze sharply in the comfort temperature range of 73--77{degree}F for use in solar passive heating and cooling of buildings. Define practical materials and processes for fire retarding plasterboard/PCM building products. Develop cost-effective methods for incorporating PCM into building construction materials (concrete, plasterboard, etc.) which will lead to the commercial manufacture and sale of PCM-containing products resulting in significant energy conservation.

  10. The Solar Heating and Cooling Commercial Demonstration Program at Marshall Space Flight Center - Some problems and conclusions

    NASA Technical Reports Server (NTRS)

    Middleton, R. L.

    1978-01-01

    The origin and evolution of the Solar Heating and Cooling Commercial Demonstration Program by the Department of Energy and the Marshall Space Flight Center activities supporting this program from its conception are defined and discussed. Problems are summarized in the design and financial areas. It is concluded that the program has significantly assisted the creation of a viable solar testing and cooling industry. The cost effective procedures evolving from the program are expected to make a major contribution to reducing the effective life cycle cost of solar installation.

  11. Multi-criteria decision analysis of concentrated solar power with thermal energy storage and dry cooling.

    PubMed

    Klein, Sharon J W

    2013-12-17

    Decisions about energy backup and cooling options for parabolic trough (PT) concentrated solar power have technical, economic, and environmental implications. Although PT development has increased rapidly in recent years, energy policies do not address backup or cooling option requirements, and very few studies directly compare the diverse implications of these options. This is the first study to compare the annual capacity factor, levelized cost of energy (LCOE), water consumption, land use, and life cycle greenhouse gas (GHG) emissions of PT with different backup options (minimal backup (MB), thermal energy storage (TES), and fossil fuel backup (FF)) and different cooling options (wet (WC) and dry (DC). Multicriteria decision analysis was used with five preference scenarios to identify the highest-scoring energy backup-cooling combination for each preference scenario. MB-WC had the highest score in the Economic and Climate Change-Economy scenarios, while FF-DC and FF-WC had the highest scores in the Equal and Availability scenarios, respectively. TES-DC had the highest score for the Environmental scenario. DC was ranked 1-3 in all preference scenarios. Direct comparisons between GHG emissions and LCOE and between GHG emissions and land use suggest a preference for TES if backup is require for PT plants to compete with baseload generators. PMID:24245524

  12. Large Eddy Simulation of complex sidearms subject to solar radiation and surface cooling.

    PubMed

    Dittko, Karl A; Kirkpatrick, Michael P; Armfield, Steven W

    2013-09-15

    Large Eddy Simulation (LES) is used to model two lake sidearms subject to heating from solar radiation and cooling from a surface flux. The sidearms are part of Lake Audrey, NJ, USA and Lake Alexandrina, SA, Australia. The simulation domains are created using bathymetry data and the boundary is modelled with an Immersed Boundary Method. We investigate the cooling and heating phases with separate quasi-steady state simulations. Differential heating occurs in the cavity due to the changing depth. The resulting temperature gradients drive lateral flows. These flows are the dominant transport process in the absence of wind. Study in this area is important in water quality management as the lateral circulation can carry particles and various pollutants, transporting them to and mixing them with the main lake body. PMID:23863384

  13. Hot carrier solar cell absorbers: investigation of carrier cooling properties of candidate materials

    NASA Astrophysics Data System (ADS)

    Conibeer, G.; Shrestha, Santosh; Huang, Shujuan; Patterson, Robert; Xia, Hongze; Feng, Yu; Zhang, Pengfei; Gupta, Neeti; Smyth, Suntrana; Liao, Yuanxun; Lin, Shu; Wang, Pei; Dai, Xi; Chung, Simon; Yang, Jianfeng; Zhang, Yi

    2015-09-01

    The hot carrier cell aims to extract the electrical energy from photo-generated carriers before they thermalize to the band edges. Hence it can potentially achieve a high current and a high voltage and hence very high efficiencies up to 65% under 1 sun and 86% under maximum concentration. To slow the rate of carrier thermalisation is very challenging, but modification of the phonon energies and the use of nanostructures are both promising ways to achieve some of the required slowing of carrier cooling. A number of materials and structures are being investigated with these properties and test structures are being fabricated. Initial measurements indicate slowed carrier cooling in III-Vs with large phonon band gaps and in multiple quantum wells. It is expected that soon proof of concept of hot carrier devices will pave the way for their development to fully functioning high efficiency solar cells.

  14. Central Data Processing System (CDPS) user's manual: Solar heating and cooling program

    NASA Technical Reports Server (NTRS)

    1976-01-01

    The software and data base management system required to assess the performance of solar heating and cooling systems installed at multiple sites is presented. The instrumentation data associated with these systems is collected, processed, and presented in a form which supported continuity of performance evaluation across all applications. The CDPS consisted of three major elements: communication interface computer, central data processing computer, and performance evaluation data base. Users of the performance data base were identified, and procedures for operation, and guidelines for software maintenance were outlined. The manual also defined the output capabilities of the CDPS in support of external users of the system.

  15. Assessment of the solar heating and cooling in residential building demonstration program

    NASA Astrophysics Data System (ADS)

    Wolff, D. C.

    1980-08-01

    The Solar Heating and Cooling in Residential Building Demonstration of 1974 is assessed. The program's goals and the Government Accounting Office's (GAO) evaluation of the program's success are stated. The program is analyzed with regard to objectives, results, data, and the GAO's conclusions. The differing approaches of the GAO and the Department of Housing and Urban Development to the program are analyzed and compared, showing weaknesses in each. Conclusions on the relative success of the program are drawn, and recommendations are made regarding any future programs of this type.

  16. Solar-powered/fuel-assisted Rankine cycle power and cooling system - Sensitivity analysis

    NASA Astrophysics Data System (ADS)

    Lior, N.; Koai, K.

    1984-11-01

    The subject of this analysis is a solar power/cooling system based on a novel hybrid steam Rankine cycle. Steam is generated by the use of solar energy collected at about 100 C, and it is then superheated to about 600 C in a fossil-fuel-fired superheater. The addition of about 20-26 percent of energy as fuel doubles the power cycle's efficiency as compared to organic fluid Rankine cycles operating at similar collector temperatures. A sensitivity analysis of the system's performance to the size and type of its components was performed by a transient (hourly) computer simulation over the month of August in two representative climatic regions (Washington, D.C. and Phoenix, Ariz.), and led to the description of a system configuration which provides optimal energy performance. The newly designed turbine's predicted efficiency is seen to be essentially invariant with system configuration, and has a monthly average value of about 73 percent.

  17. Solar heating, cooling, and domestic hot water system installed at Kaw Valley State Bank and Trust Company, Topeka, Kansas

    NASA Astrophysics Data System (ADS)

    1980-11-01

    The building has approximately 5600 square feet of conditioned space. Solar energy was used for space heating, space cooling, and preheating domestic hot water (DHW). The solar energy system had an array of evacuated tube-type collectors with an area of 1068 square feet. A 50/50 solution of ethylene glycol and water was the transfer medium that delivered solar energy to a tube-in-shell heat exchanger that in turn delivered solar heated water to a 1100 gallon pressurized hot water storage tank. When solar energy was insufficient to satisfy the space heating and/or cooling demand, a natural gas-fired boiler provided auxiliary energy to the fan coil loops and/or the absorption chillers. Extracts from the site files, specification references, drawings, and installation, operation and maintenance instructions are presented.

  18. Solar heating, cooling, and domestic hot water system installed at Kaw Valley State Bank and Trust Company, Topeka, Kansas

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The building has approximately 5600 square feet of conditioned space. Solar energy was used for space heating, space cooling, and preheating domestic hot water (DHW). The solar energy system had an array of evacuated tube-type collectors with an area of 1068 square feet. A 50/50 solution of ethylene glycol and water was the transfer medium that delivered solar energy to a tube-in-shell heat exchanger that in turn delivered solar heated water to a 1100 gallon pressurized hot water storage tank. When solar energy was insufficient to satisfy the space heating and/or cooling demand, a natural gas-fired boiler provided auxiliary energy to the fan coil loops and/or the absorption chillers. Extracts from the site files, specification references, drawings, and installation, operation and maintenance instructions are presented.

  19. Energy-conserving passive solar multi-family retrofit projects. Cycle 5, category 1: HUD Solar Heating and Cooling Demonstration Program

    NASA Astrophysics Data System (ADS)

    1981-10-01

    A total of 14 passive solar retrofit buildings are described. The concept of passive solar energy and the various types of passive systems found in the Cycle 5 projects are discussed. Each of the 14 solar designs is described, and some of the key points raised in the discussion of passive concepts are illustrated. Each project description cites the location of the passive solar home and presents the following information: grantee/builder, designer, solar designer, price, number of units, net heated area, heat load, degree days, solar fraction of the total heat load, and auxiliary heat required. Project descriptions also include data on recognition factors (the five passive elements necessary for a complete passive system), the type of auxiliary heating system used in the building, the solar water heating system (if any), and the passive cooling techniques used (if any).

  20. Solar engineering - 1981; Proceedings of the Third Annual Conference on Systems Simulation, Economic Analysis/Solar Heating and Cooling Operational Results, Reno, NV, April 27-May 1, 1981

    NASA Astrophysics Data System (ADS)

    Reid, R. L.; Murphy, L. M.; Ward, D. S.

    Progress made toward the commercialization of solar energy technologies as of 1981 is assessed, and attention is given to the future uses and impacts of solar energy. Attention is given to the results of several years of monitoring and modifying solar heating and cooling on residential and commercial structures. Solar system simulation and analysis methods are reviewed, covering the performance and operations of passive and active systems, thermosyphon systems, heat pumps and phase change systems. Simulations of system components are discussed, as are means to validate existing computer simulation codes, particularly the TRNSYS program. Control systems and logic for collector systems are explored, including analyses of building loads and climates, and numerical models of the economics of solar heating systems are presented. Performance simulations and economic analyses are also outlined for wind and photovoltaic systems, and for industrial solar heating systems. Finally, fundamental studies of corrosion, steam flow, wind loading, and scaling in solar systems are described.

  1. Thermal analysis of the plant encapsulation-dehydration cryopreservation protocol using silica gel as the desiccant.

    PubMed

    Sherlock, Graham; Block, William; Benson, Erica E

    2005-01-01

    The encapsulation-dehydration cryopreservation protocol is critically dependent upon the evaporative desiccation step, which must optimise survival with the retention of glass stability on sample cooling and rewarming. Desiccation is usually achieved evaporatively by drying in a sterile airflow. However, chemical desiccation using silica gel has advantages for laboratories that do not have environmental control and/or which are exposed to high relative humidities and risks of microbial contamination. This study characterised thermal profiles of silica gel-desiccated encapsulated shoot-tips of two Ribes species using Differential Scanning Calorimetry. For both species silica gel-desiccation at 16 degrees C for 5 h decreased bead water content from ca. 75 to 28% fresh weight (3.8 to 0.4 g x g(-1) dry weight); further desiccation (for 6 and 7 h) reduced the bead water content to 21% (0.3 g x g(-1) dry weight). These changes in water status altered the thermal properties of beads for both species. After 7 h desiccation over silica gel stable glass transitions were observed on both cooling and rewarming of beads containing meristems. Tg mid-point temperatures ranged from -78 to -51 degrees C (cooling) and from -88 to -54 degrees C (warming) [at cooling and warming rates of 10 and 5 degrees C min(-1), respectively] after 5 to 7 h silica gel-desiccation. Post-cryopreservation viability of both species was ca. 63%. Thermal analysis studies revealed that an encapsulation/dehydration protocol using silica gel as a desiccant should comprise a minimum 5 h drying (at 16 degrees C). This reduces bead moisture content to a critical point (ca. 0.4 g x g(-1) dry weight) at which stable glasses are formed on cooling and rewarming. It is concluded that silica gel has advantages for use as a desiccant for alginate-encapsulated plant meristems by promoting stable vitrification and is useful in laboratories and/or geographical locations where environmental conditions are not under

  2. An innovative system for heating and cooling a gymnasium using integrated photovoltaic-thermal solar collectors

    SciTech Connect

    Fanchiotti, A.; Herkel, S.; Laukamp, H.; Priolo, C.

    1996-11-01

    The paper describes a new solar energy based system to heat and cool a gymnasium and to generate electricity in the city of Palermo, Italy. The gymnasium will be built in 1996 as part of the structures that will host the Universiadi Games in 1997. Main objectives of the project are: (a) to grant better environmental conditions in the area occupied by the public, with limited use of fossil energy; (b) to reduce the temperature of the photovoltaic elements, thus increasing their efficiency. The system consists of an array of 203 m{sup 2} integrated photovoltaic-thermal solar air collectors. In the winter mode of operation, the heated air is passed through the concrete benches where the public is seated. In the summer mode of operation outside air is evaporatively cooled, passed through the benches, then exhausted to the outside after passing through the collectors. The paper presents some of the results obtained by simulating the system at the design stage for winter conditions.

  3. Elemental abundances in atmospheres of cool dwarfs with solar-like activity

    NASA Astrophysics Data System (ADS)

    Antipova, L. I.; Boyarchuk, A. A.

    2016-01-01

    The elemental abundances in the atmosphere of the red dwarf HD 32147, which belongs to the HR 1614 moving groups, are analyzed. The atmospheric parameters determined from spectroscopic data (the condition of equal abundances for neutral and ionized atoms of a given element) differ considerably from those derived from photometry and parallax data. The abundances of several elements are also anomalous, with the anomaly increasing with decreasing ionization potential. It is concluded that this star is a red dwarf displaying solar-like activity; i.e., having dark (cool) spots on its surface, which may sometimes be considerable in size. Modeling synthetic spectra of stars with cool spots on their surfaces, with the spectral lines consisting of two components formed in media with different temperatures, indicate that the spectroscopic atmospheric parameters derived in such cases are incorrect; this can also explain the observed dependence of the elemental abundances on the corresponding ionization potentials. This leads to the conclusion thatHD32147 is indeed a star with solar-like activity. Several other such stars considered as examples display the same anomalies as those of HD 32147. These modeling results are also valid for Ap and Am stars, and are able to explain short-wavelength observations of the Sun and some stars (the FIP effect).

  4. Plate coil thermal test bench for the Daniel K. Inouye Solar Telescope (DKIST) carousel cooling system

    NASA Astrophysics Data System (ADS)

    Phelps, LeEllen; Murga, Gaizka; Montijo, Guillermo; Hauth, David

    2014-08-01

    Analyses have shown that even a white-painted enclosure requires active exterior skin-cooling systems to mitigate dome seeing which is driven by thermal nonuniformities that change the refractive index of the air. For the Daniel K. Inouye Solar Telescope (DKIST) Enclosure, this active surface temperature control will take the form of a system of water cooled plate coils integrated into the enclosure cladding system. The main objective of this system is to maintain the surface temperature of the enclosure as close as possible to, but always below, local ambient temperature in order to mitigate this effect. The results of analyses using a multi-layer cladding temperature model were applied to predict the behavior of the plate coil cladding system and ultimately, with safety margins incorporated into the resulting design thermal loads, the detailed designs. Construction drawings and specifications have been produced. Based on these designs and prior to procurement of the system components, a test system was constructed in order to measure actual system behavior. The data collected during seasonal test runs at the DKIST construction site on Haleakalā are used to validate and/or refine the design models and construction documents as appropriate. The test fixture was also used to compare competing hardware, software, components, control strategies, and configurations. This paper outlines the design, construction, test protocols, and results obtained of the plate coil thermal test bench for the DKIST carousel cooling system.

  5. Integrated energy, economic, and environmental assessment for the optimal solar absorption cooling and heating system

    NASA Astrophysics Data System (ADS)

    Hang, Yin

    Buildings in the United States are responsible for 41% of the primary energy use and 30% of carbon dioxide emissions. Due to mounting concerns about climate change and resource depletion, meeting building heating and cooling demand with renewable energy has attracted increasing attention in the energy system design of green buildings. One of these approaches, the solar absorption cooling and heating (SACH) technology can be a key solution to addressing the energy and environmental challenges. SACH system is an integration of solar thermal heating system and solar thermal driven absorption cooling system. So far, SACH systems still remain at the demonstration and testing stage due to not only its high cost but also complicated system characteristics. This research aims to develop a methodology to evaluate the life cycle energy, economic and environmental performance of SACH systems by high-fidelity simulations validated by experimental data. The developed methodology can be used to assist the system design. In order to achieve this goal, the study includes four objectives as follows: * Objective 1: Develop the evaluation model for the SACH system. The model includes three aspects: energy, economy, and environment from a life cycle point of view. * Objective 2: Validate the energy system model by solar experiments performance data. * Objective 3: Develop a fast and effective multi-objective optimization methodology to find the optimal system configuration which achieves the maximum system benefits on energy, economy and environment. Statistic techniques are explored to reveal the relations between the system key parameters and the three evaluation targets. The Pareto front is generated by solving this multi-objective optimization problem. * Objective 4: Apply the developed assessment methodology to different building types and locations. Furthermore, this study considered the influence of the input uncertainties on the overall system performance. The sensitivity

  6. Solar collector studies for solar heating and cooling applications. Final technical report

    SciTech Connect

    Anderson, J. H.; Jensen, S. O.; Kovacic, J. E.

    1980-01-01

    A summary of the literature, especially patent teachings pertaining to black fluid solar collectors is given. Laboratory tests to determine the suspension stability of various carbon types in water/Propylene glycol are reported. The suspensions were aged at 160/sup 0/F for 3600 hours and at -15/sup 0/F for 1100 hours. It is suggested that the suspending agent interacts with electrical charges on the carbon particles to prevent agglomeration. The liquid was tested for its operating characteristics with several collector design variables using glass tubes as the containment system. The collectors were installed in a house previously operated on a black liquid system, and observed for a six month period with the weather ranging from -12/sup 0/F to 94/sup 0/F with no major problems occurring with either the liquid or the collectors.

  7. Implications of the lack of desiccation tolerance in recalcitrant seeds.

    PubMed

    Berjak, Patricia; Pammenter, Norman W

    2013-01-01

    A suite of interacting processes and mechanisms enables tolerance of desiccation and storage (conservation) of orthodox seeds in the dry state. While this is a long-term option under optimized conditions, dry orthodox seeds are not immortal, with life spans having been characterized as short, intermediate and long. Factors facilitating desiccation tolerance are metabolic "switch-off" and intracellular dedifferentiation. Recalcitrant seeds lack these mechanisms, contributing significantly to their desiccation sensitivity. Consequently, recalcitrant seeds, which are shed at high water contents, can be stored only in the short-term, under conditions not allowing dehydration. The periods of such hydrated storage are constrained by germination that occurs without the need for extraneous water, and the proliferation of seed-associated fungi. Cryopreservation is viewed as the only option for long-term conservation of the germplasm of recalcitrant-seeded species. This is not easily achieved, as each of the necessary procedures imposes oxidative damage. Intact recalcitrant seeds cannot be cryopreserved, the common practice being to use excised embryos or embryonic axes as explants. Dehydration is a necessary procedure prior to exposure to cryogenic temperatures, but this is associated with metabolism-linked injury mediated by uncontrolled reactive oxygen species generation and failing anti-oxidant systems. While the extent to which this occurs can be curtailed by maximizing drying rate (flash drying) it cannot be completely obviated. Explant cooling for, and rewarming after, cryostorage must necessarily be rapid, to avoid ice crystallization. The ramifications of desiccation sensitivity are discussed, as are problems involved in cryostorage, particularly those accompanying dehydration and damage consequent upon ice crystallization. While desiccation sensitivity is a "fact" of seed recalcitrance, resolutions of the difficulties involved germplasm conservation are possible as

  8. Implications of the lack of desiccation tolerance in recalcitrant seeds

    PubMed Central

    Berjak, Patricia; Pammenter, Norman W.

    2013-01-01

    A suite of interacting processes and mechanisms enables tolerance of desiccation and storage (conservation) of orthodox seeds in the dry state. While this is a long-term option under optimized conditions, dry orthodox seeds are not immortal, with life spans having been characterized as short, intermediate and long. Factors facilitating desiccation tolerance are metabolic “switch-off” and intracellular dedifferentiation. Recalcitrant seeds lack these mechanisms, contributing significantly to their desiccation sensitivity. Consequently, recalcitrant seeds, which are shed at high water contents, can be stored only in the short-term, under conditions not allowing dehydration. The periods of such hydrated storage are constrained by germination that occurs without the need for extraneous water, and the proliferation of seed-associated fungi. Cryopreservation is viewed as the only option for long-term conservation of the germplasm of recalcitrant-seeded species. This is not easily achieved, as each of the necessary procedures imposes oxidative damage. Intact recalcitrant seeds cannot be cryopreserved, the common practice being to use excised embryos or embryonic axes as explants. Dehydration is a necessary procedure prior to exposure to cryogenic temperatures, but this is associated with metabolism-linked injury mediated by uncontrolled reactive oxygen species generation and failing anti-oxidant systems. While the extent to which this occurs can be curtailed by maximizing drying rate (flash drying) it cannot be completely obviated. Explant cooling for, and rewarming after, cryostorage must necessarily be rapid, to avoid ice crystallization. The ramifications of desiccation sensitivity are discussed, as are problems involved in cryostorage, particularly those accompanying dehydration and damage consequent upon ice crystallization. While desiccation sensitivity is a “fact” of seed recalcitrance, resolutions of the difficulties involved germplasm conservation are

  9. Solar heating, cooling and domestic hot water system installed at Columbia Gas System Service Corporation, Columbus, Ohio

    NASA Astrophysics Data System (ADS)

    1980-11-01

    The solar energy system installed in the building has 2,978 sq ft of single axis tracking, concentrating collectors and provides solar energy for space heating, space cooling and domestic hot water. A 1,200,000 Btu/hour water tube gas boiler provides hot water for space heating. Space cooling is provided by a 100 ton hot water fired absorption chiller. Domestic hot water heating is provided by a 50 gallon natural gas domestic storage water heater. Extracts from the site files, specification references, drawings, installation, operation and maintenance instructions are included.

  10. Solar heating, cooling and domestic hot water system installed at Columbia Gas System Service Corporation, Columbus, Ohio

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The solar energy system installed in the building has 2,978 sq ft of single axis tracking, concentrating collectors and provides solar energy for space heating, space cooling and domestic hot water. A 1,200,000 Btu/hour water tube gas boiler provides hot water for space heating. Space cooling is provided by a 100 ton hot water fired absorption chiller. Domestic hot water heating is provided by a 50 gallon natural gas domestic storage water heater. Extracts from the site files, specification references, drawings, installation, operation and maintenance instructions are included.

  11. Solar heating, cooling and domestic hot water system installed at Columbia Gas System Service Corp. , Columbus, Ohio. Final report

    SciTech Connect

    1980-11-01

    The Solar Energy System located at the Columbia Gas Corporation, Columbus, Ohio, has 2978 ft/sup 2/ of Honeywell single axis tracking, concentrating collectors and provides solar energy for space heating, space cooling and domestic hot water. A 1,200,000 Btu/h Bryan water-tube gas boiler provides hot water for space heating. Space cooling is provided by a 100 ton Arkla hot water fired absorption chiller. Domestic hot water heating is provided by a 50 gallon natural gas domestic storage water heater. Extracts are included from the site files, specification references, drawings, installation, operation and maintenance instructions.

  12. Incorporation of Solar Noble Gases from a Nebula-Derived Atmosphere During Magma Ocean Cooling

    NASA Technical Reports Server (NTRS)

    Woolum, D. S.; Cassen, P.; Wasserburg, G. J.; Porcelli, D.; DeVincenzi, Donald (Technical Monitor)

    1998-01-01

    The presence of solar noble gases in the deep interior of the Earth is inferred from the Ne isotopic compositions of MORB (Mid-ocean Ridge Basalts) and OIB (Oceanic Island Basalt); Ar data may also consistent with a solar component in the deep mantle. Models of the transport and distribution of noble gases in the earth's mantle allow for the presence of solar Ar/Ne and Xe/Ne ratios and permit the calculation of lower mantle noble gas concentrations. These mantle data and models also indicate that the Earth suffered early (0.7 to 2 x 10(exp 8) yr) and large (greater than 99 percent) losses of noble gases from the interior, a result previously concluded for atmospheric Xe. We have pursued the suggestion that solar noble gases were incorporated in the forming Earth from a massive, nebula-derived atmosphere which promoted large-scale melting, so that gases from this atmosphere dissolved in the magma ocean and were mixed downward. Models of a primitive atmosphere captured from the solar nebula and supported by accretion luminosity indicate that pressures at the Earth's surface were adequate (and largely more than the required 100 Atm) to dissolve sufficient gases. We have calculated the coupled evolution of the magma ocean and the overlying atmosphere under conditions corresponding to the cessation (or severe attenuation) of the sustaining accretion luminosity, prior to the complete removal of the solar nebula. Such a condition was likely to obtain, for instance, when most of the unaccumulated mass resided in large bodies which were only sporadically accreted. The luminosity supporting the atmosphere is then that provided by the cooling Earth, consideration of which sets a lower limit to the time required to solidify the mantle and terminate the incorporation of atmospheric gases within it. In our initial calculations, we have fixed the nebula temperature at To = 300K, a value likely to be appropriate for nebular temperatures at lAU in the early planet-building epoch

  13. Forced- and natural-convection studies on solar collectors for heating and cooling applications

    NASA Astrophysics Data System (ADS)

    Pearson, J. T.

    1983-03-01

    Convection in air heating solar collectors for heating and cooling applications was studied. It was determined that improvement in the overall conductance between the absorber and the flowing air was an area that needed much improvement. Studies were performed to obtain several absorber convector configurations which have superior heat transfer performance, modest drop penalties, and a high potential for economical manufacturing. Four surfaces which may be fabricated from aluminum or steel are recommended. Three utilize corrugated sheets bonded to the backplate and/or the back side of the absorber. These three surfaces are recommended for applications where airflow behind the absorber is appropriate. For those applications where airflow above the absorber is appropriate, a louvered surface which can be fabricated from metal or plastic is recommended.

  14. Final draft: IEA Task 1. Report on Subtask D, optimization of solar heating and cooling systems

    SciTech Connect

    Freeman, T.L.

    1981-03-01

    A review of general techniques and specific methods useful in the optimization of solar heating and cooling systems is undertaken. A discussion of the state-of-the-art and the principal problems in both the simplified thermal performance analysis and economic analysis portions of the optimization problem are presented. Sample economic analyses are performed using several widely used economic criteria. The predicted thermal results of one typical, widely used simplified method is compared to detailed simulation results. A methodology for and the results of a sensitivity study of key economic parameters in the life cycle cost method are presented. Finally, a simple graphical optimization technique based on the life cycle cost method is proposed.

  15. Upgrading the Solar-Stellar Connection: News about activity in Cool Stars

    NASA Astrophysics Data System (ADS)

    Gunther, H. M.; Poppenhaeger, K.; Testa, P.; Borgniet, S.; Brun, A. S.; Cegla, H. M.; Garraffo, C.; Kowalski, A.; Shapiro, A.; Shkolnik, E.; Spada, F.; Vidotto, A. A.

    2015-01-01

    In this splinter session, ten speakers presented results on solar and stellar activity and how the two fields are connected. This was followed by a lively discussion and supplemented by short, one-minute highlight talks. The talks presented new theoretical and observational results on mass accretion on the Sun, the activity rate of flare stars, the evolution of the stellar magnetic field on time scales of a single cycle and over the lifetime of a star, and two different approaches to model the radial-velocity jitter in cool stars that is due to the granulation on the surface. Talks and discussion showed how much the interpretation of stellar activity data relies on the sun and how the large number of objects available in stellar studies can extend the parameter range of activity models.

  16. DIRECT EVIDENCE FOR CONDENSATION IN THE EARLY SOLAR SYSTEM AND IMPLICATIONS FOR NEBULAR COOLING RATES

    SciTech Connect

    Berg, T.; Maul, J.; Schoenhense, G.; Marosits, E.; Hoppe, P.; Ott, U.; Palme, H.

    2009-09-10

    We have identified in an acid resistant residue of the carbonaceous chondrite Murchison a large number (458) of highly refractory metal nuggets (RMNs) that once were most likely hosted by Ca,Al-rich inclusions (CAIs). While osmium isotopic ratios of two randomly selected particles rule out a presolar origin, the bulk chemistry of 88 particles with sizes in the submicron range determined by energy dispersive X-ray (EDX) spectroscopy shows striking agreement with predictions of single-phase equilibrium condensation calculations. Both chemical composition and morphology strongly favor a condensation origin. Particularly important is the presence of structurally incompatible elements in particles with a single-crystal structure, which also suggests the absence of secondary alteration. The metal particles represent the most pristine early solar system material found so far and allow estimation of the cooling rate of the gaseous environment from which the first solids formed by condensation. The resulting value of 0.5 K yr{sup -1} is at least 4 orders of magnitude lower than the cooling rate of molten CAIs. It is thus possible, for the first time, to see through the complex structure of most CAIs and infer the thermal history of the gaseous reservoir from which their components formed by condensation.

  17. Establish feasibility for providing passive cooling with solar updraft and evaporative downdraft chimneys. Final report, June 15, 1984--December 31, 1987

    SciTech Connect

    Cunningham, W.A.; Mignon, G.V.; Thompson, T.L.

    1987-12-31

    Natural draft towers can be used for cooling and ventilating structures. From an operational perspective, the downdraft evaporatively cooled tower is preferred for a dry climate. Solar chimneys, when used alone, tend to require an excessively large solar collector area when appreciable quantities of air must be moved. When used in combination with a downdraft tower, the roof and attic of buildings may assist the solar chimney and their use becomes more attractive. Both a frame building and a greenhouse were successfully cooled during this program. The economics of the downdraft tower compare favorably with conventional evaporative cooling for some application.

  18. Establish feasibility for providing passive cooling with solar updraft and evaporate downdraft chimneys. Final report, June 15, 1984--December 31, 1987

    SciTech Connect

    Cunningham, W.A.; Mignon, G.V.; Thompson, T.L.

    1987-12-31

    Natural draft towers can be used for cooling and ventilating structures. From an operational perspective, the downdraft evaporatively cooled tower is preferred for a dry climate. Solar chimneys, when used alone, tend to require an excessively large solar collector area when appreciable quantities of air must be moved. When used in combination with a downdraft tower, the roof and attic of buildings may assist the solar chimney and their use becomes more attractive. Both a frame building and a greenhouse were successfully cooled during this program. The economics of the downdraft tower compare favorably with conventional evaporative cooling for some applications.

  19. Introduction to Solar Heating and Cooling Systems. D.O.T. 637.281 and .381. Instructor's Guide.

    ERIC Educational Resources Information Center

    Grimes, L. A., Jr.

    This instructor's guide on solar heating and cooling is part of a series of individualized instructional materials. The guide is provided to help the instructor make certain that each student gets the most benefit possible from both the student's manual and what he/she does on the job. Notes for the instructor contain suggestions on how the…

  20. Introduction to Solar Heating and Cooling Systems. D.O.T. 637.281 and .381. Student's Manual.

    ERIC Educational Resources Information Center

    Grimes, L. A., Jr.

    This manual on solar heating and cooling systems is one of a series of individualized instructional materials for students. The manual is self-paced, but is designed to be used under the supervision of a coordinator or an instructor. The manual contains 15 assignments, each with all the information needed, a list of objectives that should be met,…

  1. Thermodynamic optimization of a solar system for cogeneration of water heating/purification and absorption cooling

    NASA Astrophysics Data System (ADS)

    Hovsapian, Zohrob O.

    This dissertation presents a contribution to understanding the behavior of solar powered air conditioning and refrigeration systems with a view to determining the manner in which refrigeration rate; mass flows, heat transfer areas, and internal architecture are related. A cogeneration system consisting of a solar concentrator, a cavity-type receiver, a gas burner, and a thermal storage reservoir is devised to simultaneously produce water heating/purification and cooling (absorption refrigerator system). A simplified mathematical model, which combines fundamental and empirical correlations, and principles of classical thermodynamics, mass and heat transfer, is developed. An experimental setup was built to adjust and validate the numerical results obtained with the mathematical model. The proposed model is then utilized to simulate numerically the system transient and steady state response under different operating and design conditions. A system global optimization for maximum performance (or minimum exergy destruction) in the search for minimum pull-down and pull-up times, and maximum system second law efficiency is performed with low computational time. Appropriate dimensionless groups are identified and the results presented in normalized charts for general application. The numerical results show that the three way maximized system second law efficiency, etaII,max,max,max, occurs when three system characteristic mass flow rates are optimally selected in general terms as dimensionless heat capacity rates, i.e., (Psisps , Psiwxwx, PsiHs)opt ≅ (1.43, 0.17, 0.19). The minimum pull-down and pull-up times, and maximum second law efficiencies found with respect to the optimized operating parameters are sharp and, therefore important to be considered in actual design. As a result, the model is expected to be a useful tool for simulation, design, and optimization of solar energy systems in the context of distributed power generation.

  2. Comparative Expression Profiling of Desiccation Tolerant and Sensitive Plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Drought tolerance and desiccation tolerance have often been cited as manifestations of the same mechanism: desiccation tolerance being the extreme form of drought tolerance. However, there is a fundamental difference between drought and desiccation tolerance; drought tolerance mechanisms include way...

  3. Design, evaluation and recommedation effort relating to the modification of a residential 3-ton absorption cycle cooling unit for operation with solar energy

    NASA Technical Reports Server (NTRS)

    Merrick, R. H.; Anderson, P. P.

    1973-01-01

    The possible use of solar energy powered absorption units to provide cooling and heating of residential buildings is studied. Both, the ammonia-water and the water-lithium bromide cycles, are considered. It is shown that the air cooled ammonia water unit does not meet the criteria for COP and pump power on the cooling cycle and the heat obtained from it acting as a heat pump is at too low a temperature. If the ammonia machine is water cooled it will meet the design criteria for cooling but can not supply the heating needs. The water cooled lithium bromide unit meets the specified performance for cooling with appreciably lower generator temperatures and without a mechanical solution pump. It is recommeded that in the demonstration project a direct expansion lithium bromide unit be used for cooling and an auxiliary duct coil using the solar heated water be employed for heating.

  4. Active Desiccant Dehumidification Module Integration with Rooftop Packaged HVAC

    SciTech Connect

    Fischer, J

    2002-04-17

    This report summarizes a research and development program that produced a stand-alone active desiccant module (ADM) that can be easily integrated with new or existing packaged cooling equipment. The program also produced a fully integrated hybrid system, combining the active desiccant section with a conventional direct expansion air-conditioning unit, that resulted in a compact, low-cost, energy-efficient end product. Based upon the results of this investigation, both systems were determined to be highly viable products for commercialization. Major challenges--including wheel development, compact packaging, regeneration burner development, control optimization, and low-cost design--were all successfully addressed by the final prototypes produced and tested as part of this program. Extensive laboratory testing was completed in the SEMCO laboratory for each of the two ADM system approaches. This testing confirmed the performance of the ADM systems to be attractive compared with that of alternate approaches currently used to precondition outdoor air, where a return air path is not readily available for passive desiccant recovery or where first cost is the primary design criterion. Photographs, schematics, and performance maps are provided for the ADM systems that were developed; and many of the control advantages are discussed. Based upon the positive results of this research and development program, field tests are under way for fully instrumented pilot installations of ADM systems in both a hotel/motel and a restaurant.

  5. Development of Desiccant System using Wakkanai Siliceous Shale

    NASA Astrophysics Data System (ADS)

    Nakabayashi, Saya; Nagano, Katsunori; Nakamura, Makoto; Togawa, Junya; Kurokawa, Asami

    The aim of this study is to develop a desiccant system using Wakkanai siliceous shale. A honeycombed desiccant rotor containing this shale's powder and chlorides was made and evaluated. However a specific surface area and a pore volume were smaller than a silica-gel rotor or a zeolite rotor, the maximum amount of water adsorption was twice as other rotors. We have verified the function of this desiccant rotor concerning adsorption and desorption of moisture from the draft experiments. The rotor containing the shale could adsorb moisture stably in the cyclic test, and be regenerated by 40°C air under this experimental condition. This means that the exhaust heat from the heat pump can be used for regenerating rotor. Furthermore, the numerical simulation was carried out on the assumption that this rotor was used for a dehumidification for the residential air conditioning in Tokyo. This rotor could adsorb 37.1% moisture of the required dehumidification amount for the hottest day in 2008. When we employed a pre-cooling before dehumidification, the amount of adsorption increased to 66.2%.

  6. Efficiently-cooled plasmonic amorphous silicon solar cells integrated with a nano-coated heat-pipe plate

    PubMed Central

    Zhang, Yinan; Du, Yanping; Shum, Clifford; Cai, Boyuan; Le, Nam Cao Hoai; Chen, Xi; Duck, Benjamin; Fell, Christopher; Zhu, Yonggang; Gu, Min

    2016-01-01

    Solar photovoltaics (PV) are emerging as a major alternative energy source. The cost of PV electricity depends on the efficiency of conversion of light to electricity. Despite of steady growth in the efficiency for several decades, little has been achieved to reduce the impact of real-world operating temperatures on this efficiency. Here we demonstrate a highly efficient cooling solution to the recently emerging high performance plasmonic solar cell technology by integrating an advanced nano-coated heat-pipe plate. This thermal cooling technology, efficient for both summer and winter time, demonstrates the heat transportation capability up to ten times higher than those of the metal plate and the conventional wickless heat-pipe plates. The reduction in temperature rise of the plasmonic solar cells operating under one sun condition can be as high as 46%, leading to an approximate 56% recovery in efficiency, which dramatically increases the energy yield of the plasmonic solar cells. This newly-developed, thermally-managed plasmonic solar cell device significantly extends the application scope of PV for highly efficient solar energy conversion. PMID:27113558

  7. Efficiently-cooled plasmonic amorphous silicon solar cells integrated with a nano-coated heat-pipe plate

    NASA Astrophysics Data System (ADS)

    Zhang, Yinan; Du, Yanping; Shum, Clifford; Cai, Boyuan; Le, Nam Cao Hoai; Chen, Xi; Duck, Benjamin; Fell, Christopher; Zhu, Yonggang; Gu, Min

    2016-04-01

    Solar photovoltaics (PV) are emerging as a major alternative energy source. The cost of PV electricity depends on the efficiency of conversion of light to electricity. Despite of steady growth in the efficiency for several decades, little has been achieved to reduce the impact of real-world operating temperatures on this efficiency. Here we demonstrate a highly efficient cooling solution to the recently emerging high performance plasmonic solar cell technology by integrating an advanced nano-coated heat-pipe plate. This thermal cooling technology, efficient for both summer and winter time, demonstrates the heat transportation capability up to ten times higher than those of the metal plate and the conventional wickless heat-pipe plates. The reduction in temperature rise of the plasmonic solar cells operating under one sun condition can be as high as 46%, leading to an approximate 56% recovery in efficiency, which dramatically increases the energy yield of the plasmonic solar cells. This newly-developed, thermally-managed plasmonic solar cell device significantly extends the application scope of PV for highly efficient solar energy conversion.

  8. Efficiently-cooled plasmonic amorphous silicon solar cells integrated with a nano-coated heat-pipe plate.

    PubMed

    Zhang, Yinan; Du, Yanping; Shum, Clifford; Cai, Boyuan; Le, Nam Cao Hoai; Chen, Xi; Duck, Benjamin; Fell, Christopher; Zhu, Yonggang; Gu, Min

    2016-01-01

    Solar photovoltaics (PV) are emerging as a major alternative energy source. The cost of PV electricity depends on the efficiency of conversion of light to electricity. Despite of steady growth in the efficiency for several decades, little has been achieved to reduce the impact of real-world operating temperatures on this efficiency. Here we demonstrate a highly efficient cooling solution to the recently emerging high performance plasmonic solar cell technology by integrating an advanced nano-coated heat-pipe plate. This thermal cooling technology, efficient for both summer and winter time, demonstrates the heat transportation capability up to ten times higher than those of the metal plate and the conventional wickless heat-pipe plates. The reduction in temperature rise of the plasmonic solar cells operating under one sun condition can be as high as 46%, leading to an approximate 56% recovery in efficiency, which dramatically increases the energy yield of the plasmonic solar cells. This newly-developed, thermally-managed plasmonic solar cell device significantly extends the application scope of PV for highly efficient solar energy conversion. PMID:27113558

  9. 9 CFR 113.29 - Determination of moisture content in desiccated biological products.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... bottles with airtight glass stoppers. (2) Vacuum oven equipped with validated thermometer and thermostat... labeled sample-weighing bottles with stoppers should be allowed to dry at 60 ±3 °C under vacuum at less than 2.5 kPa. (i) Transfer hot bottles and stoppers into the desiccator and allow to cool to...

  10. Colorado State University program for developing, testing, evaluating and optimizing solar heating and cooling systems. Project status report, December 1994--January 1995

    SciTech Connect

    1995-03-01

    This progress report summarizes activities, experiments, and testing performed on a variety of solar heating and cooling systems in conjunction with four technical research tasks. Areas of focus include: Unique solar system components; Rating and certification of domestic water heating systems; and, Advanced residential solar domestic hot water systems.

  11. Performance of evacuated tubular solar collectors in a residential heating and cooling system. Final report, 1 October 1978-30 September 1979

    SciTech Connect

    Duff, W.S.; Loef, G.O.G.

    1981-03-01

    Operation of CSU Solar House I during the heating season of 1978-1979 and during the 1979 cooling season was based on the use of systems comprising an experimental evacuated tubular solar collector, a non-freezing aqueous collection medium, heat exchange to an insulated conventional vertical cylindrical storage tank and to a built-up rectangular insulated storage tank, heating of circulating air by solar heated water and by electric auxiliary in an off-peak heat storage unit, space cooling by lithium bromide absorption chiller, and service water heating by solar exchange and electric auxiliary. Automatic system control and automatic data acquisition and computation are provided. This system is compared with others evaluated in CSU Solar Houses I, II and III, and with computer predictions based on mathematical models. Of the 69,513 MJ total energy requirement for space heating and hot water during a record cold winter, solar provided 33,281 MJ equivalent to 48 percent. Thirty percent of the incident solar energy was collected and 29 percent was delivered and used for heating and hot water. Of 33,320 MJ required for cooling and hot water during the summer, 79 percent or 26,202 MJ were supplied by solar. Thirty-five percent of the incident solar energy was collected and 26 percent was used for hot water and cooling in the summer. Although not as efficient as the Corning evacuated tube collector previously used, the Philips experimental collector provides solar heating and cooling with minimum operational problems. Improved performance, particularly for cooling, resulted from the use of a very well-insulated heat storage tank. Day time (on-peak) electric auxiliary heating was completely avoided by use of off-peak electric heat storage. A well-designed and operated solar heating and cooling system provided 56 percent of the total energy requirements for heating, cooling, and hot water.

  12. Passive solar heating and natural cooling of an earth-integrated design

    SciTech Connect

    Barnes, P.R.; Shapira, H.B.

    1980-01-01

    The Joint Institute for Heavy Ion Research is being designed with innovative features that will greatly reduce its energy consumption for heating, cooling, and lighting. A reference design has been studied and the effects of extending the overhang during summer and fall, varying glazing area, employing RIB, and reducing internal heat by natural lighting have been considered. The use of RIB and the extendable overhang increases the optimum window glazing area and the solar heating fraction. A mass-storage wall which will likely be included in the final design has also been considered. A figure of merit for commercial buildings is the total annual energy consumption per unit area of floor space. A highly efficient office building in the Oak Ridge area typically uses 120 to 160 kWhr/m/sup 2/. The Joint Institute reference design with natural lighting, an annual average heat pump coefficient of performance (COP) equal to 1.8, RIB, and the extendable overhang uses 71 kWhr/m/sup 2/. This figure was determined from NBSLD simulations corrected for the saving from RIB. The internal heat energy from lighting and equipment used in the simulation was 1653 kWhrs/month (high natural lighting case) which is much lower than conventional office buildings. This value was adopted because only a portion of the building will be used as office space and efforts will be made to keep internal heat generation low. The mass-storage wall and ambient air cooling will reduce energy consumption still further. The combined savings of the innovative features in the Joint Institute building are expected to result in a very energy efficient design. The building will be instrumented to monitor its performance and the measured data will provide a means of evaluating the energy-saving features. The efficiency of the design will be experimentally verified over the next several years.

  13. Monitoring Vadose Zone Desiccation with Geophysical Methods

    SciTech Connect

    Truex, Michael J.; Johnson, Timothy C.; Strickland, Christopher E.; Peterson, John E.; Hubbard, Susan S.

    2013-05-01

    Soil desiccation was recently field tested as a potential vadose zone remediation technology. Desiccation removes water from the vadose zone and significantly decreases the aqueous-phase permeability of the desiccated zone, thereby decreasing movement of moisture and contaminants. The 2-D and 3-D distribution of moisture content reduction over time provides valuable information for desiccation operations and for determining when treatment goals have been reached. This type of information can be obtained through use of geophysical methods. Neutron moisture logging, cross-hole electrical resistivity tomography, and cross-hole ground penetrating radar approaches were evaluated with respect to their ability to provide effective spatial and temporal monitoring of desiccation during a treatability study conducted in the vadose zone of the DOE Hanford Site in WA.

  14. Ultraviolet emission lines of Si II in cool star and solar spectra

    NASA Astrophysics Data System (ADS)

    Laha, Sibasish; Keenan, Francis P.; Ferland, Gary J.; Ramsbottom, Catherine A.; Aggarwal, Kanti M.; Ayres, Thomas R.; Chatzikos, Marios; van Hoof, Peter A. M.; Williams, Robin J. R.

    2016-01-01

    Recent atomic physics calculations for Si II are employed within the CLOUDY modelling code to analyse Hubble Space Telescope (HST) STIS ultraviolet spectra of three cool stars, β Geminorum, α Centauri A and B, as well as previously published HST/GHRS observations of α Tau, plus solar quiet Sun data from the High Resolution Telescope and Spectrograph. Discrepancies found previously between theory and observation for line intensity ratios involving the 3s23p 2PJ-3s3p2 4P_{J^' }} intercombination multiplet of Si II at ˜ 2335 Å are significantly reduced, as are those for ratios containing the 3s23p 2PJ-3s3p2 2D_{J^' }} transitions at ˜1816 Å. This is primarily due to the effect of the new Si II transition probabilities. However, these atomic data are not only very different from previous calculations, but also show large disagreements with measurements, specifically those of Calamai et al. for the intercombination lines. New measurements of transition probabilities for Si II are hence urgently required to confirm (or otherwise) the accuracy of the recently calculated values. If the new calculations are confirmed, then a long-standing discrepancy between theory and observation will have finally been resolved. However, if the older measurements are found to be correct, then the agreement between theory and observation is simply a coincidence and the existing discrepancies remain.

  15. A chemical heat pump based on the reaction of calcium chloride and methanol for solar heating, cooling and storage

    NASA Astrophysics Data System (ADS)

    Offenhartz, P. O.

    1981-03-01

    An engineering development test prototype of the CaCl2-CheOH chemical heat pump was tested. The unit, which has storage capacity in excess of 100,000 BTU, completed over 100 full charge-discharge cycles. Cycling data show that the rate of heat pumping depends strongly on the absorber-evaporator temperature difference. These rates are more than adequate for solar heating or for solar cooling using dry ambient air heat rejection. Performance degradation after 100 cycles, expressed as a contact resistance, was less than 2 C. The heat exchangers showed some warpage due to plastic flow of the salt, producing the contact resistance. The experimental COP for cooling was 0.52, close to the theoretically predicted value.

  16. Roof aperture system for selective collection and control of solar energy for building heating, cooling and daylighting

    DOEpatents

    Sanders, William J.; Snyder, Marvin K.; Harter, James W.

    1983-01-01

    The amount of building heating, cooling and daylighting is controlled by at least one pair of solar energy passing panels, with each panel of the pair of panels being exposed to a separate direction of sun incidence. A shutter-shade combination is associated with each pair of panels and the shutter is connected to the shade so that rectilinear movement of the shutter causes pivotal movement of the shade.

  17. DEVELOP A CONCENTRATED SOLAR POWER-BASED THERMAL COOLING SYSTEM VIA SIMULATION AND EXPERIMENTAL STUDIES

    EPA Science Inventory

    A small scale CSP-based cooling system prototype (300W cooling capacity) and the system performance simulation tool will be developed as a proof of concept. Practical issues will be identified to improve our design.

  18. Thermoelectric generator operating with a cooling device for converting solar energy into electric energy, and system for the use thereof

    SciTech Connect

    Cannelli, P.

    1981-06-30

    A generator of electric energy by the transformation of thermal, solar energy, or of heat of any source, is described. The generator consists in one or more thermocouples combined with a cooling device, cooling down the weldings of the thermocouples on which heat is produced by the Peltier effect, also producing a very high thermal gradient. The cooling device exploits, for the functioning thereof, the phenomena which can be observed along the thermocouples. The system for the use of such a generator provides a particular disposition of the same in parabolic collectors, as to increase the sun ray concentration onto the weldings exposed to the heat and as to allow a decentralization in the electric energy supply by means of a plurality of generators consisting in only one thermocouple, said generators being interconnected.

  19. Water isotopes in desiccating lichens

    PubMed Central

    Cuntz, Matthias; Máguas, Cristina; Lakatos, Michael

    2009-01-01

    The stable isotopic composition of water is routinely used as a tracer to study water exchange processes in vascular plants and ecosystems. To date, no study has focussed on isotope processes in non-vascular, poikilohydric organisms such as lichens and bryophytes. To understand basic isotope exchange processes of non-vascular plants, thallus water isotopic composition was studied in various green-algal lichens exposed to desiccation. The study indicates that lichens equilibrate with the isotopic composition of surrounding water vapour. A model was developed as a proof of concept that accounts for the specific water relations of these poikilohydric organisms. The approach incorporates first their variable thallus water potential and second a compartmentation of the thallus water into two isotopically distinct but connected water pools. Moreover, the results represent first steps towards the development of poikilohydric organisms as a recorder of ambient vapour isotopic composition. PMID:19888598

  20. Water isotopes in desiccating lichens.

    PubMed

    Hartard, Britta; Cuntz, Matthias; Máguas, Cristina; Lakatos, Michael

    2009-12-01

    The stable isotopic composition of water is routinely used as a tracer to study water exchange processes in vascular plants and ecosystems. To date, no study has focussed on isotope processes in non-vascular, poikilohydric organisms such as lichens and bryophytes. To understand basic isotope exchange processes of non-vascular plants, thallus water isotopic composition was studied in various green-algal lichens exposed to desiccation. The study indicates that lichens equilibrate with the isotopic composition of surrounding water vapour. A model was developed as a proof of concept that accounts for the specific water relations of these poikilohydric organisms. The approach incorporates first their variable thallus water potential and second a compartmentation of the thallus water into two isotopically distinct but connected water pools. Moreover, the results represent first steps towards the development of poikilohydric organisms as a recorder of ambient vapour isotopic composition. PMID:19888598

  1. Properties of the Carrol system and a machine design for solar-powered, air cooled, absorption space cooling

    NASA Astrophysics Data System (ADS)

    1981-05-01

    The name Carrol was selected as a convenient shorthand designation for a prime candidate chemical system comprising ethylene glycol-lithium bromide as an absorbent mixture with water as a refrigerant. The instrumentation, methods of handling data and numerical results from a systematic determination of Carrol property data required to design an air cooled absorption machine based on this chemical system are described. These data include saturation temperature, relative enthalpy, density, specific heat capacity, thermal conductivity, viscosity and absorber film heat transfer coefficient as functions of solution temperature and Carrol concentration over applicable ranges. For each of the major components of the absorption chiller, i.e., generator, chiller, absorber, condenser, heat exchanger, purge and controls, the report contains an assembly drawing and the principal operating characteristics of that component.

  2. A Helium-Cooled Absolute Cavity Radiometer For Solar And Laboratory Irradiance Measurement

    NASA Astrophysics Data System (ADS)

    Foukal, P.; Miller, P.

    1983-09-01

    We describe the design and testing of a helium-cooled absolute radiometer (HCAR) devel-oped for highly reproducible measurements of total solar irradiance and ultraviolet flux, and for laboratory standards uses. The receiver of this cryogenic radiometer is a blackened cone of pure copper whose temperature is sensed by a germanium resistance thermometer. During a duty cycle, radiant power input is compared to electrical heating in an accurate resistor wound on the receiver, as in conventional self-calibrating radiometers of the PACRAD and ACR type. But operation at helium temperatures enables us to achieve excellent radia-tive shielding between the receiver and the radiometer thermal background. This enables us to attain a sensitivity level of 10-7 watts at 30 seconds integration time, at least 10 times better than achieved by room temperature cavities. The dramatic drop of copper specific heat at helium temperatures reduces the time constant for a given mass of receiver, by a factor of 103. Together with other cryogenic materials properties such as electrical superconductivity and the high thermal conductivity of copper, this can be used to greatly reduce non-equivalence errors between electrical and radiant heating, that presently limit the absolute accuracy of radiometers to approximately 0,2%. Absolute accuracy of better than 0.01% has been achieved with a similar cryogenic radiometer in laboratory measurements of the Stefan-Boltzmann constant at NPL in the U.K. Electrical and radiometric tests con-ducted so far on our prototype indicate that comparable accuracy and long-term reproducibility can be achieved in a versatile instrument of manageable size for Shuttle flight and laboratory standards uses. This work is supported at AER under NOAA contract NA8ORAC00204 and NSF grant DMR-8260273.

  3. Modeling of solid-side mass transfer in desiccant particle beds

    SciTech Connect

    Pesaran, A.A.; Mills, A.F.

    1984-02-01

    A model is proposed for heat and mass transfer in a packed bed of desiccant particles and accounts for both Knudsen and surface diffusion within the particles. Using the model, predictions are made for the response of thin beds of silica gel particles to a step change in air inlet conditions compared to mental results. The predictions are found to be satisfactory and, in general, superior to those of pseudogas-side controlled models commonly used for the design of desiccant dehumidifiers for solar air conditioning application.

  4. Parametric study of the cyclic behaviour of a hygroscopic matrix in a desiccant airflow system

    NASA Astrophysics Data System (ADS)

    Ruivo, C. R.; Costa, J. J.; Figueiredo, A. R.

    2011-09-01

    The study of the transport phenomena in desiccant airflow systems has been addressed in numerous research works, some of them concerning combined processes of cooling, dehumidification and energy recovery. In this paper a detailed numerical model is used to simulate the behaviour of a parallel-plate channel, cyclically exposed to two airflows with different inlet conditions, the plate being composed by a substrate and a desiccant porous layer. The modelled channel is considered to be representative of a real channel of a hygroscopic matrix that is operating at steady state regime, like it occurs in desiccant or enthalpy rotors. The numerical results are treated in order to represent the global behaviour of the hygroscopic rotor under steady state conditions. Results of a parametric study are presented as maps of isovalues of the heat and mass transfer rates and of the outlet states of both airflows, considering channels of distinct wall thickness, of different thickness of the desiccant and the subtract layers, together with wide ranges of the rotation speed and of the wheel partition. The mapped results presented provide an overview of the operation characteristics of hygroscopic rotors, allowing a quick determination of the optimum range of values for relevant parameters, such as the rotation speed and the wheel partition. The model is thus an interesting tool for design and manufacture purposes of enthalpy and desiccant wheels.

  5. Development of a single-family absorption chiller for use in a solar heating and cooling system. Phase III, final report. Volume II

    SciTech Connect

    Reimann, R.C.; Biermann, W.J.

    1984-10-01

    The appendices provide supporting information on: properties of a chemical system for solar fired, air-cooled absorption equipment, air-side performance of a one-inch tube, absorber plate-fin coil, listings of the programs used for simulation and data reduction, and evaluation of the Carrier 3-ton chiller in an integrated heating and cooling system. (LEW)

  6. Development of a single-family absorption chiller for use in a solar heating and cooling system, phase 3, volume 2

    NASA Astrophysics Data System (ADS)

    Reimann, R. C.; Biermann, W. J.

    1984-10-01

    Supporting information is presented on: properties of a chemical system for solar fired, air-cooled absorption equipment, air-side performance of a one-inch tube, absorber plate-fin coil, listings of the programs used for simulation and data reduction, and evaluation of the Carrier three-tone chiller in an integrated heating and cooling system.

  7. Cool School.

    ERIC Educational Resources Information Center

    Stephens, Suzanne

    1980-01-01

    The design for Floyd Elementary School in Miami (Florida) seeks to harness solar energy to provide at least 70 percent of the annual energy for cooling needs and 90 percent for hot water. (Author/MLF)

  8. Energy and peak power saved by passively cooled residences

    NASA Astrophysics Data System (ADS)

    Clark, G.; Loxsom, F.; Doderer, E.; Vieira, R.; Fleischhacker, P.

    1983-11-01

    The energy displacement potential of roof pond cooling in humid climates is sensitive to the type of dehumidification equipment employed and the humidity levels allowed. The simulated energy requirements of roof pond residences assisted by two high efficiency dehumidifier options are described. One dehumidifier was a vapor compression air conditioner with sensible cooling recovery by an air-to-air heat exchanger (improved mechanical dehumidification or IMD). The second option was a solar regenerated desiccant dehumidifier (SRDD). An IMD assisted roof pond house had energy savings of 30 to 65% in humid climates compared to the conventional house; an SRDD assisted roof pond house had energy savings of 70 to 75% in humid climates.

  9. Installation package for integrated programmable electronic controller and hydronic subsystem - solar heating and cooling

    NASA Technical Reports Server (NTRS)

    1978-01-01

    A description is given of the Installation, Operation, and Maintenance Manual and information on the power panel and programmable microprocessor, a hydronic solar pump system and a hydronic heating hot water pumping system. These systems are integrated into various configurations for usages in solar energy management, control and monitoring, lighting control, data logging and other solar related applications.

  10. Instructor's Manual for Teaching and Practical Courses on Design of Systems and Sizing, Installation and Operation of Systems for Solar Heating and Cooling of Residential Buildings.

    ERIC Educational Resources Information Center

    Colorado State Univ., Ft. Collins. Solar Energy Applications Lab.

    Presented are guidelines for instructors of two courses in the design, installation, and operation of solar heating and cooling systems. These courses are: (1) Design of Systems, and (2) Sizing, Installation, and Operation of Systems. Limited in scope to active solar systems for residential buildings, these courses place primary emphasis upon…

  11. Development and Implementation of Training Curriculum/Program in Solar Heating and Cooling at the Technician Level, December 1, 1976 - November 30, 1977. Final Report.

    ERIC Educational Resources Information Center

    Kuhnle, Carl J., Jr.

    The program proposal is designed to address the increasing demand for trained personnel to support the installation and maintenance of solar energy systems at residential and commercial sites. The three main objectives of the proposed program are: (1) to develop a flexible curricula to train a solar heating and cooling workforce; (2) to identify…

  12. Solar Heating and Cooling of Buildings: Phase 0. Feasibility and Planning Study. Volume 1: Executive Summary. Document No. 74SD419. Final Report.

    ERIC Educational Resources Information Center

    General Electric Co., Philadelphia, PA. Space Div.

    The purpose of this study was to establish the technical and economic feasibility of using solar energy for the heating and cooling of buildings and to provide baseline information for the widespread application of solar energy. The initial step in this program was a study of the technical, economic, societal, legal, and environmental factors…

  13. COOL ROOF COATINGS INCORPORATING GLASS HOLLOW MICROSPHERES FOR IMPROVED SOLAR REFLECTANCE

    EPA Science Inventory

    Elastomeric cool-roof coatings can be applied to buildings to decrease heat gain, yielding energy savings and mitigating the “urban heat island” effect. Most cool-roof formulations are based on titanium dioxide (TiO2). While TiO2 and several TiO2

  14. Market assessment for active solar heating and cooling products. Category B: a survey of decision-makers in the HVAC marketplace. Final report

    SciTech Connect

    1980-09-01

    A comprehensive evaluation of the market for solar heating and cooling products for new and retrofit markets is reported. The emphasis is on the analysis of solar knowledge among HVAC decision makers and a comprehensive evaluation of their solar attitudes and behavior. The data from each of the following sectors are described and analyzed: residential consumers, organizational and manufacturing buildings, HVAC engineers and architects, builders/developers, and commercial/institutional segments. (MHR)

  15. A comparison of fuel savings in the residential and commercial sectors generated by the installation of solar heating and cooling systems under three tax credit scenarios

    NASA Astrophysics Data System (ADS)

    Moden, R.

    An analysis of expected energy savings between 1977 and 1980 under three different solar tax credit scenarios is presented. The results were obtained through the solar heating and cooling of buildings (SHACOB) commercialization model. This simulation provides projected savings of conventional fuels through the installation of solar heating and cooling systems on buildings in the residential and commercial sectors. The three scenarios analyzed considered the tax credits contained in the Windfall Profits Tax of April 1980, the National Tax Act of November 1978, and a case where no tax credit is in effect.

  16. Desiccation tolerance in Bryophytes: relevance to the evolution of desiccation tolerance in Land Plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The majority of desiccation-tolerant plants are found in the less complex clades that constitute the algae, lichens and bryophytes. However, within the larger and more complex groups of vascular land plants there are some 120-130 species that exhibit some degree of vegetative desiccation tolerance. ...

  17. Spectroscopic study of a dark lane and a cool loop in a solar limb active region by Hinode/EIS

    SciTech Connect

    Lee, Kyoung-Sun; Imada, S.; Moon, Y.-J.; Lee, Jin-Yi

    2014-01-10

    We investigated a cool loop and a dark lane over a limb active region on 2007 March 14 using the Hinode/EUV Imaging Spectrometer. The cool loop is clearly seen in the spectral lines formed at the transition region temperature. The dark lane is characterized by an elongated faint structure in the coronal spectral lines and is rooted on a bright point. We examined their electron densities, Doppler velocities, and nonthermal velocities as a function of distance from the limb. We derived electron densities using the density sensitive line pairs of Mg VII, Si X, Fe XII, Fe XIII, and Fe XIV spectra. We also compared the observed density scale heights with the calculated scale heights from each peak formation temperatures of the spectral lines under the hydrostatic equilibrium. We noted that the observed density scale heights of the cool loop are consistent with the calculated heights, with the exception of one observed cooler temperature; we also found that the observed scale heights of the dark lane are much lower than their calculated scale heights. The nonthermal velocity in the cool loop slightly decreases along the loop, while nonthermal velocity in the dark lane sharply falls off with height. Such a decrease in the nonthermal velocity may be explained by wave damping near the solar surface or by turbulence due to magnetic reconnection near the bright point.

  18. Polymer-based heat exchanger desiccant systems

    SciTech Connect

    Staton, J.C.; Howard, J.L.; Scott, E.P.; Kander, R.G.

    1999-07-01

    The increasing popularity of desiccant-enhanced air conditioning systems has sparked new interest in the search for a better, more efficient desiccant material. The ultimate goal of this research was to develop a material that, when applied to an existing air-to-air heat exchanger, would achieve the necessary heat and mass transfer in a single process, thus transforming a sensible heat exchanger into a total enthalpy exchanger. This study focused on the development and determination of appropriate polymeric desiccant materials for use in different heat and mass transfer systems. The specific objectives for the study were to select an appropriate polymer desiccant, determine the necessary materials properties for this material, and develop and implement mathematical models to analyze the desiccant performance. Two systems were investigated for this study: a rotary wheel total enthalpy exchanger and a fixed plate total enthalpy exchanger. Seven different polymer materials were analyzed to determine the most suitable candidate. Although for the specific conditions studied, the commercial paper-ceramic desiccant out-performed the PVOH materials in both rotary wheel and fixed plate systems, the results suggested that two PVOH materials, PVOH open-cell foam and PVOH/silica gel/molecular sieve composite, have potential for use in total energy exchange applications. By modifying the design conditions, total efficiencies exceeding 70% were achieved for both PVOH foam and PVOH/ceramic composite in rotary wheel systems. In addition, modified the design conditions resulted in total efficiencies greater than 90% for the PVOH foam in both counter-flow and cross-flow flat plate systems. These findings indicated that with appropriate optimization of the exchanger design, these two PVOH materials could have the potential to perform as well as desiccant materials in current rotary wheel and fixed plate exchanger systems.

  19. Membrane-Based Absorption Refrigeration Systems: Nanoengineered Membrane-Based Absorption Cooling for Buildings Using Unconcentrated Solar & Waste Heat

    SciTech Connect

    2010-09-01

    BEETIT Project: UFL is improving a refrigeration system that uses low quality heat to provide the energy needed to drive cooling. This system, known as absorption refrigeration system (ARS), typically consists of large coils that transfer heat. Unfortunately, these large heat exchanger coils are responsible for bulkiness and high cost of ARS. UFL is using new materials as well as system design innovations to develop nanoengineered membranes to allow for enhanced heat exchange that reduces bulkiness. UFL’s design allows for compact, cheaper and more reliable use of ARS that use solar or waste heat.

  20. Program plan for reliability and maintainability in active solar heating and cooling systems

    SciTech Connect

    Not Available

    1980-10-01

    This document presents a plan for the Department of Energy, Office of Solar Applications for Buildings program addressing reliability and maintainability (R and M) of active solar energy systems. The goal of the R and M program is to accelerate the removal of reliability and maintainability as major concerns impeding the widespread adoption of solar energy systems. Specific objectives that support that goal are as follows: (1) provide all groups that have solar R and M concerns with the information that is available to the program and that can assist in alleviating those concerns; (2) assist the solar energy industry in improving levels of R and M performance in state-of-the-art solar energy systems, components, and materials; (3) assist in the early development of a viable infrastructure for the design, manufacture, installation, and maintenance of reliable, maintainable, and durable solar energy systems; (4) assist in the development of appropriate standards, code provisions, and certification programs relating to the R and M performance of solar energy systems, components, and materials; and (5) develop the information required to support the other activities within the R and M program. These objectives correspond to five areas of action: regulations, research and development, technology transfer, solar industry infrastructure development, and data collection and analysis. (WHK)

  1. Analysis of heat and mass transfer between air and falling film desiccant for different flow configurations in the presence of ultrafine particles

    NASA Astrophysics Data System (ADS)

    Ali, Ahmad A.

    This work focuses on the enhancement of heat and mass transfer between air and falling desiccant film for different flow channel configurations. Cu-Ultrafine particles are added to the desiccant film to investigate the enhancement in heat and mass transfer between air and desiccant film for dehumidification and cooling processes of the air and regeneration of desiccant film. A detailed comparative study between parallel and counter flow channels is performed using a parametric study to investigate the enhancements in dehumidification, cooling, and regeneration processes in terms of the pertinent parameters. The results reveal that the parallel flow arrangement provides better dehumidification and cooling for the air than the counter flow channel for a wide range of parameters. Next, the inclined parallel and counter flow configurations are investigated using an Alternating Direction Implicit (ADI) and successive over-relaxation methods to discretize the vorticity and stream-function equations, respectively. A parametric study is employed to investigate the inclination angle effects in enhancing the heat and mass transfer in terms of the controlling parameters. It is shown that inclination angle plays a significant role in enhancing the dehumidification, cooling, and regeneration processes. Finally, the enhancements in heat and mass transfer in cross flow channel between air and desiccant film is examined based on a parametric study to investigate the dehumidification and cooling processes of the air in terms of the pertinent controlling parameters. These parameters are air and desiccant Reynolds numbers, dimensions of the channel, volume fraction of Cu-ultrafine particles, and thermal dispersion effects. It is found that an increase in the Cu-volume fraction increases dehumidification and cooling capabilities and produce more stable Cu-desiccant film.

  2. Numerical simulation of an innovated building cooling system with combination of solar chimney and water spraying system

    NASA Astrophysics Data System (ADS)

    Rabani, Ramin; Faghih, Ahmadreza K.; Rabani, Mehrdad; Rabani, Mehran

    2014-05-01

    In this study, passive cooling of a room using a solar chimney and water spraying system in the room inlet vents is simulated numerically in Yazd, Iran (a hot and arid city with very high solar radiation). The performance of this system has been investigated for the warmest day of the year (5 August) which depends on the variation of some parameters such as water flow rate, solar heat flux, and inlet air temperature. In order to get the best performance of the system for maximum air change and also absorb the highest solar heat flux by the absorber in the warmest time of the day, different directions (West, East, North and South) have been studied and the West direction has been selected as the best direction. The minimum amount of water used in spraying system to set the inside air averaged relative humidity <65 % is obtained using trial and error method. The simulation results show that this proposed system decreases the averaged air temperature in the middle of the room by 9-14 °C and increases the room relative humidity about 28-45 %.

  3. Owens-Illinois subsystem design package for the SEC-601 air-cooled solar collector

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The subsystem design of the SEC-601 solar collector was evaluated. The collector is of modular design and is approximately 12 feet three inches wide and eight feet seven inches tall. It contains 72 collector tube elements and weighs approximately 300 pounds. Included in this report are the subsystem performance specifications and the assembly and installation drawings of the solar collectors and manifold.

  4. Solar heating, cooling, and domestic hot water system installed at Kaw Valley State Bank and Trust Company, Topeka, Kansas. Final report

    SciTech Connect

    1980-11-01

    The building has approximately 5600 square feet of conditioned space. Solar energy is used for space heating, space cooling, and preheating domestic hot water (DHW). The solar energy system has an array of evacuated tube-type collectors with an area of 1068 square feet. A 50/50 solution of ethylene glycol and water is the transfer medium that delivers solar energy to a tube-in-shell heat exchanger that in turn delivers solar-heated water to a 1100 gallon pressurized hot water storage tank. When solar energy is insufficient to satisfy the space heating and/or cooling demand, a natural gas-fired boiler provides auxiliary energy to the fan coil loops and/or the absorption chillers. Extracts from the site files, specification references, drawings, and installation, operation and maintenance instructions are included.

  5. Vapor pressures of the aqueous desiccants

    SciTech Connect

    Chung, T.W.; Luo, C.M.

    1999-09-01

    The vapor pressures of the aqueous desiccants lithium chloride, lithium bromide, calcium chloride, ethylene glycol, propylene glycol, and their mixtures were measured at their typical operating concentrations and at temperatures from 298 K to 313 K. The experimental data were fitted to an Antoine type of equation, ln[P(kPa)] = A {minus} B/[T(K) + C], where A, B, and C are constants and are concentration dependent. Vapor pressure data were further used to predict the effectiveness of dehumidification in liquid desiccant dehumidifiers.

  6. Adsorption/Desorption Behavior Of Water Vapor In An Adsorbent Desiccant Rotor

    NASA Astrophysics Data System (ADS)

    Tsujiguchi, Takuya; Kodama, Akio

    Desiccant cooling system can be driven with a low temperature heat such as around 80°C obtained from exhaust gas and so on. Among the configuration of the cooling cycle, honeycomb rotary adsorber is the most important part to achieve higher cooling performance. By means of computer simulation, angular and axial distributions of the amount of adsorbed water, air humidity, air temperature and adsorbent temperature inside the desiccant rotor at various operating conditions were investigated. In the mathematical model, lumped mass transfer coefficient was used and its value were derived from the fitting with experimental results to improve the reliability of discussion about the simultaneous heat/mass transfer in the desiccant rotor. It was found that the part of honeycomb rotary adsorber which is close to the regeneration air inlet cannot work well as an adsorbent at higher regeneration temperature regardless of outside air condition and regeneration air humidity. On the other hand, since the driving force was extremely low throughout all the axial positions, water vapor was adsorbed gradually at the whole axial position of rotor under a lower regeneration temperature. Consequently, this study could clarify the importance of the optimization of the rotor in terms of its length depending on the operating and air conditions.

  7. Desiccation of unsaturated porous media: Intermediate-scale experiments and numerical simulation

    SciTech Connect

    Oostrom, Martinus; Wietsma, Thomas W.; Dane, J. H.; Truex, Michael J.; Ward, Anderson L.

    2009-08-01

    Soil desiccation (drying) is recognized as a potentially robust vadose zone remediation process involving water evaporation induced by air injection and extraction. Desiccation has the potential to immobilize contaminants and could potentially improve access for other gas-phase treatments by reducing water saturation and therefore increasing sediment gas-phase permeability. Before this technology could be deployed in the field, concerns related to energy limitations, osmotic effects, and potential contaminant remobilization after rewetting need to be addressed. A series of detailed wedge-shaped, intermediate-scale laboratory experiments in unsaturated homogeneous and simple heterogeneous systems was conducted to improve the understanding of the impact of energy balance issues on soil desiccation. The experiments were simulated with the multifluid flow simulator STOMP, using independently obtained hydraulic and thermal porous medium properties. In all the experiments, the injection of dry air proved to be an effective means for removing essentially all moisture from the test media. Evaporative cooling was observed which generally decreased with increased distance from the gas inlet chamber. Observations of temperature in fine-grained sands in the heterogeneous systems show two local temperature minima associated with the cooling. The first one occurs because of evaporation in the adjacent medium-grained sand whereas the second minimum is attributed to evaporative cooling in the fine-grained sand itself. Results of the laboratory tests were simulated accurately when thermal properties of the flow cell walls and insulation material were taken into account, indicating that the proper physics were incorporated into the simulator.

  8. System integration of marketable subsystems. [for residential solar heating and cooling

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Progress is reported in the following areas: systems integration of marketable subsystems; development, design, and building of site data acquisition subsystems; development and operation of the central data processing system; operation of the MSFC Solar Test Facility; and systems analysis.

  9. Development of flat-plate solar collectors for the heating and cooling of buildings

    NASA Technical Reports Server (NTRS)

    Ramsey, J. W.; Borzoni, J. T.; Holland, T. H.

    1975-01-01

    The relevant design parameters in the fabrication of a solar collector for heating liquids were examined. The objective was to design, fabricate, and test a low-cost, flat-plate solar collector with high collection efficiency, high durability, and requiring little maintenance. Computer-aided math models of the heat transfer processes in the collector assisted in the design. The preferred physical design parameters were determined from a heat transfer standpoint and the absorber panel configuration, the surface treatment of the absorber panel, the type and thickness of insulation, and the number, spacing and material of the covers were defined. Variations of this configuration were identified, prototypes built, and performance tests performed using a solar simulator. Simulated operation of the baseline collector configuration was combined with insolation data for a number of locations and compared with a predicted load to determine the degree of solar utilization.

  10. Development of flat-plate solar collectors for the heating and cooling of buildings: Executive summary

    NASA Technical Reports Server (NTRS)

    1978-01-01

    An efficient, low cost, flat-plate solar collector was developed. Computer aided mathematical models of the heat process in the collector were used in defining absorber panel configuration; determining insulation thickness; and in selecting the number, spacing, and material of the covers. Prototypes were built and performance tested. Data from simulated operation of the collector are compared with predicted loads from a number of locations to determine the degree of solar utilization.

  11. Thermal and economic assessment of hot side sensible heat and cold side phase change storage combination fo absorption solar cooling system

    NASA Astrophysics Data System (ADS)

    Choi, M. K.; Morehouse, J. H.

    An analysis of a solar assisted absorption cooling system which employs a combination of phase change on the cold side and sensible heat storage on the hot side of the cooling machine for small commercial buildings is given. The year-round thermal performance of this system for space cooling were determined by simulation and compared against conventional cooling systems in three geographic locations: Phoenix, Arizona; Miami, Florida and Washington, D.C. The results indicate that the hot-cold storage combination has a considerable amount of energy and economical savings over hot side sensible heat storage. Using the hot-cold storage combination, the optimum collector areas for Washington, D.C., Phoenix and Miami are 355 m squared, 250 m squared and 495 m squared, respectively. Compared against conventional vapor compression chiller, the net solar fractions are 61, 67 and 69 percent, respectively.

  12. Cool heliosheath plasma and deceleration of the upstream solar wind at the termination shock.

    PubMed

    Richardson, John D; Kasper, Justin C; Wang, Chi; Belcher, John W; Lazarus, Alan J

    2008-07-01

    The solar wind blows outward from the Sun and forms a bubble of solar material in the interstellar medium. The termination shock occurs where the solar wind changes from being supersonic (with respect to the surrounding interstellar medium) to being subsonic. The shock was crossed by Voyager 1 at a heliocentric radius of 94 au (1 au is the Earth-Sun distance) in December 2004 (refs 1-3). The Voyager 2 plasma experiment observed a decrease in solar wind speed commencing on about 9 June 2007, which culminated in several crossings of the termination shock between 30 August and 1 September 2007 (refs 4-7). Since then, Voyager 2 has remained in the heliosheath, the region of shocked solar wind. Here we report observations of plasma at and near the termination shock and in the heliosheath. The heliosphere is asymmetric, pushed inward in the Voyager 2 direction relative to the Voyager 1 direction. The termination shock is a weak, quasi-perpendicular shock that heats the thermal plasma very little. An unexpected finding is that the flow is still supersonic with respect to the thermal ions downstream of the termination shock. Most of the solar wind energy is transferred to the pickup ions or other energetic particles both upstream of and at the termination shock. PMID:18596800

  13. Adsorption / Desorption Behavior of Water Vapor in an Adsorbent Desiccant Rotor

    NASA Astrophysics Data System (ADS)

    Tsujiguchi, Takuya; Kodama, Akio

    Adsorption / desorption behavior of water vapor onto desiccant rotor has been investigated to improve the desiccant cooling system by means of computer simulation. In this paper, we paid attention to the relationship between the equilibrium amount of water adsorbed onto the desiccant material and the relative humidity, that is adsorption isotherm as a principal characteristic feature of adsorbent. Considering actual adsorbents, five types of adsorption isotherms were assumed to clarify the influence of adsorption isotherm on the dehumidifying performance. After the investigation on the influences of some operating conditions on the dehumidifying performance at each selected adsorption isotherm, it was found that higher dehumidifying performance and reduction of length of desiccant rotor could be achieved by selecting appropriate adsorption isotherm. It was also predicted that S-shaped adsorption isotherm which is raised sharply at relative humidity around 15 % could produce the lowest air humidity at regeneration air temperature 80 °C. Moreover influence of the intraparticle diffusion coefficient which significantly influence on the adsorption / desorption rate was discussed choosing two adsorption isotherm from the above five isotherms. It seems that effective range of the intraparticle diffusion coefficient for the significant improvement of the dehumidifying performance was strongly influenced by the shape of adsorption isotherm.

  14. Adsorption/Desorption Behavior of Water Vapor in an Adsorbent Desiccant Rotor

    NASA Astrophysics Data System (ADS)

    Tsujiguchi, Takuya; Kodama, Akio

    To clarify the operating and design concept of desiccant rotor, which is a most important component of an adsorptive desiccant cooling process, adsorption / desorption behavior of water vapor in a desiccant rotor has been investigated by means of computer simulation. Mass transfer coefficient in the mathematical model could be related to cycle time by applying the penetration theory. Considering this relationship, influences of the rotation speed of the desiccant rotor, process / regeneration air velocity and their velocity ratio were investigated. It was found that the optimum rotation speed tended to disappear when the regeneration air temperature was low and its humidity was considerably small compared to the process inlet air, since the product air condition approached to regeneration air condition as the rotation speed increased. Decrease of the dehumidifying performance was observed at higher air velocity and the corresponding higher rotation speed since the adsorbent rotor was not fully regenerated due to shorter regeneration time and shorter residence time of process / regeneration air in the adsorbent rotor prevented the mass transfer between air and adsorbent. It was also found that the dehumidifying performance was not improved even though the adsorbent was fully regenerated by higher regeneration air velocity as the sensible heat transferred from the regeneration zone via adsorbent itself increased and disturbed adsorption.

  15. Experimental performance study of a proposed desiccant based air conditioning system.

    PubMed

    Bassuoni, M M

    2014-01-01

    An experimental investigation on the performance of a proposed hybrid desiccant based air conditioning system referred as HDBAC is introduced in this paper. HDBAC is mainly consisted of a liquid desiccant dehumidification unit integrated with a vapor compression system (VCS). The VCS unit has a cooling capacity of 5.27 kW and uses 134a as refrigerant. Calcium chloride (CaCl2) solution is used as the working desiccant material. HDBAC system is used to serve low sensible heat factor applications. The effect of different parameters such as, process air flow rate, desiccant solution flow rate, evaporator box and condenser box solution temperatures, strong solution concentration and regeneration temperature on the performance of the system is studied. The performance of the system is evaluated using some parameters such as: the coefficient of performance (COPa), specific moisture removal and energy saving percentage. A remarkable increase of about 54% in the coefficient of performance of the proposed system over VCS with reheat is achieved. A maximum overall energy saving of about 46% is observed which emphasizes the use of the proposed system as an energy efficient air conditioning system. PMID:25685475

  16. Experimental performance study of a proposed desiccant based air conditioning system

    PubMed Central

    Bassuoni, M.M.

    2013-01-01

    An experimental investigation on the performance of a proposed hybrid desiccant based air conditioning system referred as HDBAC is introduced in this paper. HDBAC is mainly consisted of a liquid desiccant dehumidification unit integrated with a vapor compression system (VCS). The VCS unit has a cooling capacity of 5.27 kW and uses 134a as refrigerant. Calcium chloride (CaCl2) solution is used as the working desiccant material. HDBAC system is used to serve low sensible heat factor applications. The effect of different parameters such as, process air flow rate, desiccant solution flow rate, evaporator box and condenser box solution temperatures, strong solution concentration and regeneration temperature on the performance of the system is studied. The performance of the system is evaluated using some parameters such as: the coefficient of performance (COPa), specific moisture removal and energy saving percentage. A remarkable increase of about 54% in the coefficient of performance of the proposed system over VCS with reheat is achieved. A maximum overall energy saving of about 46% is observed which emphasizes the use of the proposed system as an energy efficient air conditioning system. PMID:25685475

  17. Decay-phase cooling and inferred heating of M- and X-class solar flares

    SciTech Connect

    Ryan, Daniel F.; Gallagher, Peter T.; Chamberlin, Phillip C.; Milligan, Ryan O.

    2013-11-20

    In this paper, the cooling of 72 M- and X-class flares is examined using GOES/XRS and SDO/EVE. The observed cooling rates are quantified and the observed total cooling times are compared with the predictions of an analytical zero-dimensional hydrodynamic model. We find that the model does not fit the observations well, but does provide a well-defined lower limit on a flare's total cooling time. The discrepancy between observations and the model is then assumed to be primarily due to heating during the decay phase. The decay-phase heating necessary to account for the discrepancy is quantified and found be ∼50% of the total thermally radiated energy, as calculated with GOES. This decay-phase heating is found to scale with the observed peak thermal energy. It is predicted that approximating the total thermal energy from the peak is minimally affected by the decay-phase heating in small flares. However, in the most energetic flares the decay-phase heating inferred from the model can be several times greater than the peak thermal energy.

  18. Comparative metabolic profiling between desiccation-sensitive and desiccation-tolerant species of Selaginella reveals insights into the resurrection trait

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spike-mosses (Selaginellaceae) represent an ancient lineage of vascular plants in which some species have evolved or revolved desiccation tolerance (DT). A sister group comparison was conducted between a desiccation-tolerant species, Selaginella lepidophylla, and a desiccation-sensitive species, S. ...

  19. Solar Central Receiver Hybrid Power Systems sodium-cooled receiver concept. Final report. Volume III. Appendices

    SciTech Connect

    1980-01-01

    The overall, long term objective of the Solar Central Receiver Hybrid Power System is to identify, characterize, and ultimately demonstrate the viability and cost effectiveness of solar/fossil, steam Rankine cycle, hybrid power systems that: (1) consist of a combined solar central receiver energy source and a nonsolar energy source at a single, common site, (2) may operate in the base, intermediate, and peaking capacity modes, (3) produce the rated output independent of variations in solar insolation, (4) provide a significant savings (50% or more) in fuel consumpton, and (5) produce power at the minimum possible cost in mills/kWh. It is essential that these hybrid concepts be technically feasible and economically competitive with other systems in the near to mid-term time period (1985-1990) on a commercial scale. The program objective for Phase I is to identify and conceptually characterize solar/fossil steam Rankine cycle, commercial-scale, power plant systems that are economically viable and technically feasible. This volume contains appendices to the conceptual design and systems analysis studies gien in Volume II, Books 1 and 2. (WHK)

  20. TROPICAL SPIDERWORT STEM DESICCATION AND RECOVERY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tropical spiderwort has the curious ability to survive periods of drought stress, even as segmented pieces of stem. The purpose of this study was to establish the moisture level to which stems of tropical spiderwort (TSW) must desiccate in order to effectively kill the plant regenerative process. ...

  1. Trehalose Accumulation Triggers Autophagy during Plant Desiccation.

    PubMed

    Williams, Brett; Njaci, Isaac; Moghaddam, Lalehvash; Long, Hao; Dickman, Martin B; Zhang, Xiuren; Mundree, Sagadevan

    2015-12-01

    Global climate change, increasingly erratic weather and a burgeoning global population are significant threats to the sustainability of future crop production. There is an urgent need for the development of robust measures that enable crops to withstand the uncertainty of climate change whilst still producing maximum yields. Resurrection plants possess the unique ability to withstand desiccation for prolonged periods, can be restored upon watering and represent great potential for the development of stress tolerant crops. Here, we describe the remarkable stress characteristics of Tripogon loliiformis, an uncharacterised resurrection grass and close relative of the economically important cereals, rice, sorghum, and maize. We show that T. loliiformis survives extreme environmental stress by implementing autophagy to prevent Programmed Cell Death. Notably, we identified a novel role for trehalose in the regulation of autophagy in T.loliiformis. Transcriptome, Gas Chromatography Mass Spectrometry, immunoblotting and confocal microscopy analyses directly linked the accumulation of trehalose with the onset of autophagy in dehydrating and desiccated T. loliiformis shoots. These results were supported in vitro with the observation of autophagosomes in trehalose treated T. loliiformis leaves; autophagosomes were not detected in untreated samples. Presumably, once induced, autophagy promotes desiccation tolerance in T.loliiformis, by removal of cellular toxins to suppress programmed cell death and the recycling of nutrients to delay the onset of senescence. These findings illustrate how resurrection plants manipulate sugar metabolism to promote desiccation tolerance and may provide candidate genes that are potentially useful for the development of stress tolerant crops. PMID:26633550

  2. Trehalose Accumulation Triggers Autophagy during Plant Desiccation

    PubMed Central

    Moghaddam, Lalehvash; Long, Hao; Dickman, Martin B; Zhang, Xiuren; Mundree, Sagadevan

    2015-01-01

    Global climate change, increasingly erratic weather and a burgeoning global population are significant threats to the sustainability of future crop production. There is an urgent need for the development of robust measures that enable crops to withstand the uncertainty of climate change whilst still producing maximum yields. Resurrection plants possess the unique ability to withstand desiccation for prolonged periods, can be restored upon watering and represent great potential for the development of stress tolerant crops. Here, we describe the remarkable stress characteristics of Tripogon loliiformis, an uncharacterised resurrection grass and close relative of the economically important cereals, rice, sorghum, and maize. We show that T. loliiformis survives extreme environmental stress by implementing autophagy to prevent Programmed Cell Death. Notably, we identified a novel role for trehalose in the regulation of autophagy in T.loliiformis. Transcriptome, Gas Chromatography Mass Spectrometry, immunoblotting and confocal microscopy analyses directly linked the accumulation of trehalose with the onset of autophagy in dehydrating and desiccated T. loliiformis shoots. These results were supported in vitro with the observation of autophagosomes in trehalose treated T. loliiformis leaves; autophagosomes were not detected in untreated samples. Presumably, once induced, autophagy promotes desiccation tolerance in T.loliiformis, by removal of cellular toxins to suppress programmed cell death and the recycling of nutrients to delay the onset of senescence. These findings illustrate how resurrection plants manipulate sugar metabolism to promote desiccation tolerance and may provide candidate genes that are potentially useful for the development of stress tolerant crops. PMID:26633550

  3. Desiccation tolerance in bryophytes: a review

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Desiccation tolerance, the ability to lose virtually all free intracellular water and then recover normal function upon rehydration, is one of the most remarkable features of bryophytes. The physiology of bryophytes differs in major respects from that of vascular plants by virtue of their smaller s...

  4. Surface roughness effects on the solar reflectance of cool asphalt shingles

    SciTech Connect

    Akbari, Hashem; Berdahl, Paul; Akbari, Hashem; Jacobs, Jeffry; Klink, Frank

    2008-02-17

    We analyze the solar reflectance of asphalt roofing shingles that are covered with pigmented mineral roofing granules. The reflecting surface is rough, with a total area approximately twice the nominal area. We introduce a simple analytical model that relates the 'micro-reflectance' of a small surface region to the 'macro-reflectance' of the shingle. This model uses a mean field approximation to account for multiple scattering effects. The model is then used to compute the reflectance of shingles with a mixture of different colored granules, when the reflectances of the corresponding mono-color shingles are known. Simple linear averaging works well, with small corrections to linear averaging derived for highly reflective materials. Reflective base granules and reflective surface coatings aid achievement of high solar reflectance. Other factors that influence the solar reflectance are the size distribution of the granules, coverage of the asphalt substrate, and orientation of the granules as affected by rollers during fabrication.

  5. Self operating absorption cooling system using solar energy: Small power experimental plant

    NASA Astrophysics Data System (ADS)

    Velluet, P.; Dehausse, R.

    This study deals with a solar system for refrigeration specially designed for remote areas conditions. So, it must be very simple and reliable, and in addition it must be also mechanically self-operating. The thermodynamic cycle used is an ammonia-water absorption one. It consumes only thermal energy, which is easily and cheaply converted directly from solar radiation. In order to make a self-operating system, an engine is located between the boiler (at high pressure) and the absorber (at low pressure). It expands ammonia vapor and produces mechanical energy to run the solution pump.

  6. Evaporatively cooled chiller for solar air conditioning systems design and field test

    NASA Astrophysics Data System (ADS)

    Merrick, R. H.; Murray, J. G.

    1984-06-01

    Design changes to improve reliability, part load performance, and manufacturability characteristics of the chiller are focused upon. Low heat flux was achieved by large transfer area allows scale formation without being a thermal barrier: 80 mils = 1 deg. The scaling rate is minimized by keeping surface temperatures below 100 F and a generous water recirculation flow rate. By integrating the cooling tower function into the chiller itself parasitic power consumption was reduced 35%. This system also provided the winter freeze protection without the specific manual shut down procedures required by separate water cooled units and their towers. The severe reduction in cumulative coefficient of performance (COP) due to cycling conditions has been substantially reduced using the spin down control scheme. The major disappointment was the failure to develop a satisfactory inexpensive protective coating. Hot dip galvanizing was demonstrated to be effective but costly, partially due to transportation expense.

  7. Solar-reflective coating as a cooling overlay for asphalt pavement

    NASA Astrophysics Data System (ADS)

    Wang, He; Xu, Geng; Feng, Decheng; Zhong, Jing; Xie, Ning

    2011-11-01

    Rutting is one of the most serious problems on asphalt pavements. Decrease the surface temperature of the asphalt pavement is an effective method to solve the rutting problem on asphalt pavements. In this study, nano sized particles filled polymer composite was developed as an overlay to reflect the solar energy and decrease the surface temperature of asphalt pavements. The overlay was composed of acrylic or epoxy resin filled with nano TiO2 or nano TiNO2. The solar reflection of the nano particle filled polymers was tested and the results showed that solar reflection effectiveness of the epoxy/TiO2 composite reached the highest value. The results of outdoor temperature test indicate that the solar-reflective overlay could decrease the surface temperature of asphalt pavements about 10 °C when the pavement temperature is about 60 °C. Pavement skid resistance was also tested, which expressed by micro/macrotexture depth and the results of which showed that both matrix was qualified after coated with aggregates on the surface.

  8. Solar-reflective coating as a cooling overlay for asphalt pavement

    NASA Astrophysics Data System (ADS)

    Wang, He; Xu, Geng; Feng, Decheng; Zhong, Jing; Xie, Ning

    2012-04-01

    Rutting is one of the most serious problems on asphalt pavements. Decrease the surface temperature of the asphalt pavement is an effective method to solve the rutting problem on asphalt pavements. In this study, nano sized particles filled polymer composite was developed as an overlay to reflect the solar energy and decrease the surface temperature of asphalt pavements. The overlay was composed of acrylic or epoxy resin filled with nano TiO2 or nano TiNO2. The solar reflection of the nano particle filled polymers was tested and the results showed that solar reflection effectiveness of the epoxy/TiO2 composite reached the highest value. The results of outdoor temperature test indicate that the solar-reflective overlay could decrease the surface temperature of asphalt pavements about 10 °C when the pavement temperature is about 60 °C. Pavement skid resistance was also tested, which expressed by micro/macrotexture depth and the results of which showed that both matrix was qualified after coated with aggregates on the surface.

  9. Performance simulation of the JPL solar-powered distiller. Part 1: Quasi-steady-state conditions. [for cooling microwave equipment

    NASA Technical Reports Server (NTRS)

    Yung, C. S.; Lansing, F. L.

    1983-01-01

    A 37.85 cu m (10,000 gallons) per year (nominal) passive solar powered water distillation system was installed and is operational in the Venus Deep Space Station. The system replaced an old, electrically powered water distiller. The distilled water produced with its high electrical resistivity is used to cool the sensitive microwave equipment. A detailed thermal model was developed to simulate the performance of the distiller and study its sensitivity under varying environment and load conditions. The quasi-steady state portion of the model is presented together with the formulas for heat and mass transfer coefficients used. Initial results indicated that a daily water evaporation efficiency of 30% can be achieved. A comparison made between a full day performance simulation and the actual field measurements gave good agreement between theory and experiment, which verified the model.

  10. The Tropospheric cooling and the Stratospheric warming at Tirunelveli during the Annular Solar Eclipse of 15 January, 2010

    NASA Astrophysics Data System (ADS)

    Nelli, Narendra Reddy; Choudhary, Raj Kumar; Rao, Kusuma

    The UTLS region, a transition region between the troposphere and the stratosphere is of concern to climate scientists as its temperature variations are crucial in determining the water vapour and the other trace gases transport between the two regions, which inturn determine the radiative warming and cooling of the troposphere and the stratosphere. To examine, the temperature variations from surface to lower stratosphere,a major experiment facility was set up for upper air and surface measurements during the Annular Solar Eclipse (ASE) of January 15, 2010 at Tirunelveli (8.72 N, 77.81 E) located in 94% eclipse path in the southern peninsular India. The instruments,namely, 1. high resolution GPS radiosonde system, 2. an instrumented 15 m high Mini Boundary Layer Mast, 3. an instrumented 1 m high Near Surface Mast (NSM), radiation and other ground sensors were operated during the period 14-19 Jan, 2010. The ASE of January 15, 2010 was unique being the longest in duration (9 min, 15.3 sec) among the similar ones that occurred in the past. The major inference from an analysis of surface and upper air measurements is the occurrence of troposphere cooling during the eclipse with the peak cooling of 5 K at 15 km height with respect to no-eclispe conditions. Also, intense warming in the stratosphere is observed with the peak warming of 7 K at 19 km height.Cooling of the Troposphere as the eclipse advanced and the revival to its normal temperature is clearly captured in upper air measurements. The downward vertical velocities observed at 100 hPa in NCEP Re-analyses, consistent with the tropospheric cooling during the ASE window, may be causing the stratospheric warming. Partly, these vertical velocities could be induced by the mesoscale circulation associated with the mesoscale convective system that prevailed parallel to the eclipse path as described in METEOSAT imageries of brightness temperatures from IR channel. Further analysis is being carried out to quantify the

  11. The cool component and the dichotomy, lateral expansion, and axial rotation of solar X-ray jets

    SciTech Connect

    Moore, Ronald L.; Sterling, Alphonse C.; Falconer, David A.; Robe, Dominic

    2013-06-01

    We present results from a study of 54 polar X-ray jets that were observed in coronal X-ray movies from the X-ray Telescope on Hinode and had simultaneous coverage in movies of the cooler transition region (T ∼ 10{sup 5} K) taken in the He II 304 Å band of the Atmospheric Imaging Assembly (AIA) on Solar Dynamics Observatory. These dual observations verify the standard-jet/blowout-jet dichotomy of polar X-ray jets previously found primarily from XRT movies alone. In accord with models of blowout jets and standard jets, the AIA 304 Å movies show a cool (T ∼ 10{sup 5} K) component in nearly all blowout X-ray jets and in a small minority of standard X-ray jets, obvious lateral expansion in blowout X-ray jets but none in standard X-ray jets, and obvious axial rotation in both blowout X-ray jets and standard X-ray jets. In our sample, the number of turns of axial rotation in the cool-component standard X-ray jets is typical of that in the blowout X-ray jets, suggesting that the closed bipolar magnetic field in the jet base has substantial twist not only in all blowout X-ray jets but also in many standard X-ray jets. We point out that our results for the dichotomy, lateral expansion, and axial rotation of X-ray jets add credence to published speculation that type-II spicules are miniature analogs of X-ray jets, are generated by granule-size emerging bipoles, and thereby carry enough energy to power the corona and solar wind.

  12. To develop a dynamic model of a collector loop for purpose of improved control of solar heating and cooling. Final technical report. [TRNSYS code

    SciTech Connect

    Herczfeld, P R; Fischl, R

    1980-01-01

    The program objectives were to (1) assess the feasibility of using the TRNSYS computer code for solar heating and cooling control studies and modify it wherever possible, and (2) develop a new dynamic model of the solar collector which reflects the performance of the collector under transient conditions. Also, the sensitivity of the performance of this model to the various system parameters such as collector time constants, flow rates, turn-on and turn-off temperature set points, solar insolation, etc., was studied. Results are presented and discussed. (WHK)

  13. Colorado State University program for developing, testing, evaluating and optimizing solar heating and cooling systems: Project status report for the months of October and November, 1994

    SciTech Connect

    Not Available

    1994-12-01

    This report describes a project to develop tools for evaluating solar heating and cooling systems. Current work on this project has been to validate the Florida Solar Energy Center`s (FSEC) models of the Solahart 302K and 302K-AS systems to prepare a rating for the Sacramento Municipal Utility District`s rebate program for solar domestic hot water heaters. A preliminary rating has been issued by FSEC and updated ratings will be released as necessary. Two of the problems that were mentioned in the August/September report are addressed and a tank heat loss test is discussed. Work continues on improving and validating the models.

  14. Desiccant Humidity Control System Using Waste Heat of Water Source Heat Pump

    NASA Astrophysics Data System (ADS)

    Wada, Kazuki; Mashimo, Kouichi; Takahashi, Mikio; Tanaka, Kitoshi; Toya, Saburo; Tateyama, Ryotaro; Miyamoto, Kazuhiro; Yamaguchi, Masahiro

    The authors hope to develop an air-conditioning system that processes the latent heat load and the sensible heat load separately. This would enable the efficiency of the chilling unit to be improved because the temperature of the chilled water used for cooling would be higher than normal. However, if lukewarm water is used, there is insufficient cooling and dehumidification. Therefore, a dehumidifier such as a desiccant air-conditioning system is needed. Using the waste heat generated when the desiccant air-conditioning system is in operation increases efficiency. The authors are developing a prototype desiccant humidity control system that makes use of the waste heat generated by a water source heat pump. This paper describes the results of an experiment that was conducted for this prototype based on the assumption that it would be installed in an office building. The dehumidification performance achieved was sufficient to process the indoor latent heat load. The prototype was able to adjust the indoor relative humidity from 40% to 60% under conditions in which the indoor latent heat load varied. Humidification without the use of water was possible even in the absence of an indoor latent heat load when the outdoor absolute humidity was 3.5 g/kg' or more.

  15. Validation of the solar heating and cooling high speed performance (HISPER) computer code

    NASA Technical Reports Server (NTRS)

    Wallace, D. B.

    1980-01-01

    Developed to give a quick and accurate predictions HISPER, a simplification of the TRNSYS program, achieves its computational speed by not simulating detailed system operations or performing detailed load computations. In order to validate the HISPER computer for air systems the simulation was compared to the actual performance of an operational test site. Solar insolation, ambient temperature, water usage rate, and water main temperatures from the data tapes for an office building in Huntsville, Alabama were used as input. The HISPER program was found to predict the heating loads and solar fraction of the loads with errors of less than ten percent. Good correlation was found on both a seasonal basis and a monthly basis. Several parameters (such as infiltration rate and the outside ambient temperature above which heating is not required) were found to require careful selection for accurate simulation.

  16. Parametric study of rock pile thermal storage for solar heating and cooling phase 1

    NASA Technical Reports Server (NTRS)

    Saha, H.

    1977-01-01

    The test data and an analysis were presented, of heat transfer characteristics of a solar thermal energy storage bed utilizing water filled cans as the energy storage medium. An attempt was made to optimize can size, can arrangement, and bed flow rates by experimental and analytical means. Liquid filled cans, as storage media, utilize benefits of both solids like rocks, and liquids like water. It was found that this combination of solid and liquid media shows unique heat transfer and heat content characteristics and is well suited for use with solar air systems for space and hot water heating. An extensive parametric study was made of heat transfer characteristics of rocks, of other solids, and of solid containers filled with liquids.

  17. Validation of the solar heating and cooling high speed performance (HISPER) computer code

    NASA Astrophysics Data System (ADS)

    Wallace, D. B.

    1980-10-01

    Developed to give a quick and accurate predictions HISPER, a simplification of the TRNSYS program, achieves its computational speed by not simulating detailed system operations or performing detailed load computations. In order to validate the HISPER computer for air systems the simulation was compared to the actual performance of an operational test site. Solar insolation, ambient temperature, water usage rate, and water main temperatures from the data tapes for an office building in Huntsville, Alabama were used as input. The HISPER program was found to predict the heating loads and solar fraction of the loads with errors of less than ten percent. Good correlation was found on both a seasonal basis and a monthly basis. Several parameters (such as infiltration rate and the outside ambient temperature above which heating is not required) were found to require careful selection for accurate simulation.

  18. Solar Heating and Cooling of Buildings: Activities of the Private Sector of the Building Community and Its Perceived Needs Relative to Increased Activity.

    ERIC Educational Resources Information Center

    National Academy of Sciences - National Research Council, Washington, DC. Committee on Solar Energy in the Heating and Cooling of Buildings.

    This report is essentially a collection of information gathered from a broad cross-section of the building community that provides a description of the state of affairs existing mid-1974 through mid-1975 in the private sector of the building community with regard to solar heating and cooling of buildings. The report additionally contains…

  19. Market assessment for active solar heating and cooling products. Category B: A survey of decision makers in the HVAC market place. Survey instruments

    SciTech Connect

    Lilien, G. L.; Johnston, P. E.

    1980-09-01

    Telephone screener questionnaires and mail-out questionnaires for marketing surveys for solar heating and cooling equipment are presented. Questionnaires are included for the residential segment, industrial segment, HVAC professionals segment, builder/developer segment, and the commercial segment. No results are reported. (WHK)

  20. The development of a solar powered residential heating and cooling system

    NASA Technical Reports Server (NTRS)

    Oneill, M. J.; Mccormick, P. O.; Kruse, W. R.

    1974-01-01

    A solar energy collector design is disclosed that would be efficient for both energy transfer and fluid flow, based upon extensive parametric analyses. Thermal design requirements are generated for the energy storage systems which utilizes sensible heat storage in water. Properly size system components (including the collector and storage) and a practical, efficient total system configuration are determined by means of computer simulation of system performance.

  1. Solar/Geothermal Saves Energy in Heating and Cooling of Greenhouses

    NASA Astrophysics Data System (ADS)

    Sanders, Matthew; Thompson, Mark; Sikorski, Yuri

    2010-04-01

    The steady increase in world population and problems associated with conventional agricultural practices demand changes in food production methods and capabilities. Locally grown food minimizes the transportation costs and gas emissions responsible for Global Warming. Greenhouses have the potential to be extremely ecologically friendly by greatly increasing yields per year and facilitating reduced pesticide use. Globally, there are 2.5 million acres of greenhouse cover, including 30,640 acres in North America. In Europe, greenhouses consume 10% of the total energy in agriculture. Most of that energy is utilized for heating. Heating and cooling amount to 35% of greenhouse production costs. This high percentage value can be partially attributed to currently poor insulation values. In moderate-to-cold climate zones, it can take up to 2,500 gallons of propane, currently costing around 5,000, to keep a 2,000 sq. ft. greenhouse producing all winter. Around 350 tons of CO2 per acre per year are released from these structures, contributing to global climate change. Reducing the energy needs of a greenhouse is the first step in saving money and the environment. Therefore, an efficient and environmentally friendly heating and cooling system selection is also crucial. After selecting appropriate energy sources, the next major concern in a greenhouse would be heat loss. Consequently, it is critically important to understand factors contributing to heat loss.

  2. Indirect evaporative cooler using membrane-contained, liquid desiccant for dehumidification

    SciTech Connect

    Kozubal, Eric Joseph; Slayzak, Steven Joseph

    2014-07-08

    An indirect evaporative cooler for cooling inlet supply air from a first temperature to a second, lower temperature using a stream of liquid coolant and a stream of exhaust or purge air. The cooler includes a first flow channel for inlet supply air and a second flow channel adjacent the first for exhaust air. The first and second flow channels are defined in part by sheets of a membrane permeable to water vapor such that mass is transferred as a vapor through the membrane from the inlet supply air to a contained liquid desiccant for dehumidification and also to the exhaust air as heat is transferred from the inlet supply air to the liquid coolant. A separation wall divides the liquid desiccant and the coolant but allows heat to be transferred from the supply air to the coolant which releases water vapor to the counter or cross flowing exhaust air.

  3. Frost Growth CFD Model of an Integrated Active Desiccant Rooftop Unit

    SciTech Connect

    Geoghegan, Patrick J; Petrov, Andrei Y; Vineyard, Edward Allan; Zaltash, Abdolreza; Linkous, Randall Lee

    2008-01-01

    A frost growth model is incorporated into a Computational Fluid Dynamics (CFD) simulation of a heat pump by means of a user-defined function in FLUENT, a commercial CFD code. The transient model is applied to the outdoor section of an Integrated Active Desiccant Rooftop (IADR) unit in heating mode. IADR is a hybrid vapor compression and active desiccant unit capable of handling 100% outdoor air (dedicated outdoor air system) or as a total conditioning system, handling both outdoor air and space cooling or heating loads. The predicted increase in flow resistance and loss in heat transfer capacity due to frost build-up are compared to experimental pressure drop readings and thermal imaging. The purpose of this work is to develop a CFD model that is capable of predicting frost growth, an invaluable tool in evaluating the effectiveness of defrost-on-demand cycles.

  4. TOR and RAS pathways regulate desiccation tolerance in Saccharomyces cerevisiae

    PubMed Central

    Welch, Aaron Z.; Gibney, Patrick A.; Botstein, David; Koshland, Douglas E.

    2013-01-01

    Tolerance to desiccation in cultures of Saccharomyces cerevisiae is inducible; only one in a million cells from an exponential culture survive desiccation compared with one in five cells in stationary phase. Here we exploit the desiccation sensitivity of exponentially dividing cells to understand the stresses imposed by desiccation and their stress response pathways. We found that induction of desiccation tolerance is cell autonomous and that there is an inverse correlation between desiccation tolerance and growth rate in glucose-, ammonia-, or phosphate-limited continuous cultures. A transient heat shock induces a 5000–fold increase in desiccation tolerance, whereas hyper-ionic, -reductive, -oxidative, or -osmotic stress induced much less. Furthermore, we provide evidence that the Sch9p-regulated branch of the TOR and Ras-cAMP pathway inhibits desiccation tolerance by inhibiting the stress response transcription factors Gis1p, Msn2p, and Msn4p and by activating Sfp1p, a ribosome biogenesis transcription factor. Among 41 mutants defective in ribosome biogenesis, a subset defective in 60S showed a dramatic increase in desiccation tolerance independent of growth rate. We suggest that reduction of a specific intermediate in 60S biogenesis, resulting from conditions such as heat shock and nutrient deprivation, increases desiccation tolerance. PMID:23171550

  5. Desiccant-Based Combined Systems: Integrated Active Desiccant Rooftop Hybrid System Development and Testing Final Report- Phase 4

    SciTech Connect

    Fischer, J

    2005-05-06

    provide individual sensible and latent loads required by an occupied space without over-cooling and reheating air. The product was developed using a housing construction similar to that of a conventional packaged rooftop unit. The resulting integrated active desiccant rooftop (IADR) is similar in size to a currently available conventional rooftop unit sized to provide an equivalent total cooling capacity. Unlike a conventional rooftop unit, the IADR can be operated as a dedicated outdoor air system processing 100% outdoor air, as well as a total conditioning system capable of handling any ratio of return air to outdoor air. As part of this R&D program, a detailed investigation compared the first cost and operating cost of the IADR with costs for a conventional packaged approach for an office building located in Jefferson City, MO. The results of this comparison suggest that the IADR approach, once commercialized, could be cost-competitive with existing technology--exhibiting a one-year to two-year payback period--while simultaneously offering improved humidity control, indoor air quality, and energy efficiency.

  6. Composite desiccant material "CaCl2/Vermiculite/Saw wood": a new material for fresh water production from atmospheric air

    NASA Astrophysics Data System (ADS)

    Kumar, Manoj; Yadav, Avadhesh

    2016-04-01

    In this study a novel composite desiccant material "CaCl2/Vermiculite/Saw wood" have been synthesized and tested for the water generation from atmospheric air. The vermiculite- saw wood used as a host matrix and CaCl2 as a hygroscopic salt. A solar glass desiccant box type system with a collector area of 0.36 m2 has been used. Design parameters for water generation are height of glass from the desiccant material bed as 0.22 m, inclination in angle as 30º, the effective thickness of glass as 3 mm and number of glazing as single. It has been found that the concentration of calcium chloride is the most influencing factor for fresh water generation from atmospheric air. The maximum amount of water produced by using novel composite desiccant material is 195 ml/kg/day.

  7. Desiccant-based dehumidification system and method

    DOEpatents

    Fischer, John C.

    2004-06-22

    The present invention provides an apparatus for dehumidifying air supplied to an enclosed space by an air conditioning unit. The apparatus includes a partition separating the interior of the housing into a supply portion and a regeneration portion. The supply portion has an inlet for receiving supply air from the air conditioning unit and an outlet for supplying air to the enclosed space. A regeneration fan creates the regeneration air stream. The apparatus includes an active desiccant wheel positioned such that a portion of the wheel extends into the supply portion and a portion of the wheel extends into the regeneration portion, so that the wheel can rotate through the supply air stream and the regeneration air stream to dehumidify the supply air stream. A heater warms the regeneration air stream as necessary to regenerate the desiccant wheel. The invention also comprises a hybrid system that combines air conditioning and dehumidifying components into a single integrated unit.

  8. Desiccation kinetics of biopreservation solutions in microchannels

    PubMed Central

    Aksan, Alptekin; Irimia, Daniel; He, Xiaoming; Toner, Mehmet

    2013-01-01

    A microfluidic device was utilized to measure the viscosity gradients formed in carbohydrate solutions of biological significance during desiccation and skin formation. A complementary numerical model employed the free volume theory to predict the concentration-dependent diffusion coefficients and viscosity gradients in concentrated solutions. It was established that the glassy skin formation at the gas-liquid interface played a key role in water entrapment and the formation and persistence of very steep concentration and viscosity gradients in the desiccating solutions. The results of this study highlighted an important phenomenon that should be accounted for during isothermal drying of glass-forming solutions: solutions with high glass transition temperatures, inevitably, dry heterogeneously. In the final product, there are significant spatial variations in water and solute content affecting the storage stability. PMID:24155501

  9. Field Demonstration of Active Desiccant-Based Outdoor Air Preconditioning Systems, Final Report: Phase 3

    SciTech Connect

    Fischer, J.

    2001-07-09

    This report summarizes an investigation of the performance of two active desiccant cooling systems that were installed as pilot systems in two locations--a college dormitory and a research laboratory--during the fall of 1999. The laboratory system was assembled in the field from commercially available Trane air-handling modules combined with a standard total energy recovery module and a customized active desiccant wheel, both produced by SEMCO. The dormitory system was a factory-built, integrated system produced by SEMCO that included both active desiccant and sensible-only recovery wheels, a direct-fired gas regeneration section, and a pre-piped Trane heat pump condensing section. Both systems were equipped with direct digital control systems, complete with full instrumentation and remote monitoring capabilities. This report includes detailed descriptions of these two systems, installation details, samples of actual performance, and estimations of the energy savings realized. These pilot sites represent a continuation of previous active desiccant product development research (Fischer, Hallstrom, and Sand 2000; Fischer 2000). Both systems performed as anticipated, were reliable, and required minimal maintenance. The dehumidification/total-energy-recovery hybrid approach was particularly effective in all respects. System performance showed remarkable improvement in latent load handling capability and operating efficiency compared with the original conventional cooling system and with the conventional system that remained in another, identical wing of the facility. The dehumidification capacity of the pilot systems was very high, the cost of operation was very low, and the system was cost-effective, offering a simple payback for these retrofit installations of approximately 5 to 6 years. Most important, the dormitory system resolved numerous indoor air quality problems in the dormitory by providing effective humidity control and increased, continuous ventilation air.

  10. A review of desiccant dehumidification technology

    SciTech Connect

    Pesaran, A.A.

    1994-10-01

    This paper overviews applications of desiccant technology for dehumidifying commercial and institutional buildings. Because of various market, policy, and regulatory factors, this technology is especially attractive for dehumidification applications in the 1990s. After briefly reviewing the principle of operation, the authors present three case studies-for supermarkets, a hotel, and an office building. The authors also discuss recent advances and ongoing research and development activities.

  11. Large-Scale Coronal Heating from "Cool" Activity in the Solar Magnetic Network

    NASA Technical Reports Server (NTRS)

    Falconer, D. A.; Moore, R. L.; Porter, J. G.; Hathaway, D. H.

    1999-01-01

    In Fe XII images from SOHO/EIT, the quiet solar corona shows structure on scales ranging from sub-supergranular (i.e., bright points and coronal network) to multi-supergranular (large-scale corona). In Falconer et al 1998 (Ap.J., 501, 386) we suppressed the large-scale background and found that the network-scale features are predominantly rooted in the magnetic network lanes at the boundaries of the supergranules. Taken together, the coronal network emission and bright point emission are only about 5% of the entire quiet solar coronal Fe XII emission. Here we investigate the relationship between the large-scale corona and the network as seen in three different EIT filters (He II, Fe IX-X, and Fe XII). Using the median-brightness contour, we divide the large-scale Fe XII corona into dim and bright halves, and find that the bright-half/dim half brightness ratio is about 1.5. We also find that the bright half relative to the dim half has 10 times greater total bright point Fe XII emission, 3 times greater Fe XII network emission, 2 times greater Fe IX-X network emission, 1.3 times greater He II network emission, and has 1.5 times more magnetic flux. Also, the cooler network (He II) radiates an order of magnitude more energy than the hotter coronal network (Fe IX-X, and Fe XII). From these results we infer that: 1) The heating of the network and the heating of the large-scale corona each increase roughly linearly with the underlying magnetic flux. 2) The production of network coronal bright points and heating of the coronal network each increase nonlinearly with the magnetic flux. 3) The heating of the large-scale corona is driven by widespread cooler network activity rather than by the exceptional network activity that produces the network coronal bright points and the coronal network. 4) The large-scale corona is heated by a nonthermal process since the driver of its heating is cooler than it is. This work was funded by the Solar Physics Branch of NASA's office of

  12. Proof-of-Concept Testing of the Passive Cooling System (T-CLIP™) for Solar Thermal Applications at an Elevated Temperature

    SciTech Connect

    Kim, Seung Jun; Quintana, Donald L.; Vigil, Gabrielle M.; Perraglio, Martin Juan; Farley, Cory Wayne; Tafoya, Jose I.; Martinez, Adam L.

    2015-11-30

    The Applied Engineering and Technology-1 group (AET-1) at Los Alamos National Laboratory (LANL) conducted the proof-of-concept tests of SolarSPOT LLC’s solar thermal Temperature- Clipper, or T-CLIP™ under controlled thermal conditions using a thermal conditioning unit (TCU) and a custom made environmental chamber. The passive T-CLIP™ is a plumbing apparatus that attaches to a solar thermal collector to limit working fluid temperature and to prevent overheating, since overheating may lead to various accident scenarios. The goal of the current research was to evaluate the ability of the T-CLIP™ to control the working fluid temperature by using its passive cooling mechanism (i.e. thermosiphon, or natural circulation) in a small-scale solar thermal system. The assembled environmental chamber that is thermally controlled with the TCU allows one to simulate the various possible weather conditions, which the solar system will encounter. The performance of the T-CLIP™ was tested at two different target temperatures: 1) room temperature (70 °F) and 2) an elevated temperature (130 °F). The current test campaign demonstrated that the T-CLIP™ was able to prevent overheating by thermosiphon induced cooling in a small-scale solar thermal system. This is an important safety feature in situations where the pump is turned off due to malfunction or power outages.

  13. Performance evaluation of a solar ejector-vapour compression cycle for cooling application

    NASA Astrophysics Data System (ADS)

    Megdouli, K.; Elakhdar, M.; Nahdi, E.; Kairouani, L.; Mhimid, A.

    2015-04-01

    This study deals with the performance of the ejector-vapour compression cycle assisted by solar. The effect of operating conditions on the combined cycle performance is examined. Also, a comparison of the system performance with environment friendly refrigerants (R134a, R600, R123, R141b, R142b, R152a, R290, and R245fa) is made. This performance is calculated using an empirical correlation. Thermodynamic properties of functioning fluids are obtained with package REFPROP 8. Using the typical meteorological year file containing the weather data of the city of Tunis, the system performance is computed for three collector types. The theoretical results show that the R290 offers the highest coefficient of performance, COP=3.75, for generator temperature TB = 78°C, condenser temperature Tc = 30°C and the intercooler temperature Te = 15°C.

  14. Experimental constraints on heating and cooling rates of refractory inclusions in the early solar system

    NASA Technical Reports Server (NTRS)

    Boynton, W. V.; DRAKE; HILDEBRAND; JONES; LEWIS; TREIMAN; WARK

    1987-01-01

    The refractory inclusions in carbonaceous chondrites were the subject of considerable interest since their discovery. These inclusions contain minerals that are predicted to be some of the earliest condensates from the solar nebula, and contain a plethora of isotopic anomalies of unknown origin. Of particular interest are those coarse-grained inclusions that contain refractory metal particles (Fe, Ni, Pt, Ru, Os Ir). Experimental studies of these inclusions in terrestrial laboratories are, however, complicated because the dense particles tend to settle out of a molten or partially molten silicate material. Heating experiments in the Space Station technology and microgravity in order to observe the effects of metal nuggets (which may act as heterogeneous nucleation sites) on nucleation rates in silicate systems and to measure simultaneously the relative volatilization rate of siderophile and lithophile species. Neither experiment is possible in the terrestrial environment.

  15. Design and experimental testing of the performance of an outdoor LiBr/H{sub 2}O solar thermal absorption cooling system with a cold store

    SciTech Connect

    Agyenim, Francis; Knight, Ian; Rhodes, Michael

    2010-05-15

    A domestic-scale prototype experimental solar cooling system has been developed based on a LiBr/H{sub 2}O absorption system and tested during the 2007 summer and autumn months in Cardiff University, UK. The system consisted of a 12 m{sup 2} vacuum tube solar collector, a 4.5 kW LiBr/H{sub 2}O absorption chiller, a 1000 l cold storage tank and a 6 kW fan coil. The system performance, as well as the performances of the individual components in the system, were evaluated based on the physical measurements of the daily solar radiation, ambient temperature, inlet and outlet fluid temperatures, mass flow rates and electrical consumption by component. The average coefficient of thermal performance (COP) of the system was 0.58, based on the thermal cooling power output per unit of available thermal solar energy from the 12 m{sup 2} Thermomax DF100 vacuum tube collector on a hot sunny day with average peak insolation of 800 W/m{sup 2} (between 11 and 13.30 h) and ambient temperature of 24 C. The system produced an electrical COP of 3.6. Experimental results prove the feasibility of the new concept of cold store at this scale, with chilled water temperatures as low as 7.4 C, demonstrating its potential use in cooling domestic scale buildings. (author)

  16. Sun Heats, Cools Columbus Tech.

    ERIC Educational Resources Information Center

    American School and University, 1980

    1980-01-01

    Solar energy heats and cools the newest building on the campus of Columbus Technical Institute in Ohio. A solar demonstration project grant from the Department of Energy covered about 77 percent of the solar cost. (Author/MLF)

  17. DEVELOPMENT OF A SOFTWARE DESIGN TOOL FOR HYBRID SOLAR-GEOTHERMAL HEAT PUMP SYSTEMS IN HEATING- AND COOLING-DOMINATED BUILDINGS

    SciTech Connect

    Yavuzturk, C. C.; Chiasson, A. D.; Filburn, T. P.

    2012-11-29

    This project provides an easy-to-use, menu-driven, software tool for designing hybrid solar-geothermal heat pump systems (GHP) for both heating- and cooling-dominated buildings. No such design tool currently exists. In heating-dominated buildings, the design approach takes advantage of glazed solar collectors to effectively balance the annual thermal loads on the ground with renewable solar energy. In cooling-dominated climates, the design approach takes advantage of relatively low-cost, unglazed solar collectors as the heat rejecting component. The primary benefit of hybrid GHPs is the reduced initial cost of the ground heat exchanger (GHX). Furthermore, solar thermal collectors can be used to balance the ground loads over the annual cycle, thus making the GHX fully sustainable; in heating-dominated buildings, the hybrid energy source (i.e., solar) is renewable, in contrast to a typical fossil fuel boiler or electric resistance as the hybrid component; in cooling-dominated buildings, use of unglazed solar collectors as a heat rejecter allows for passive heat rejection, in contrast to a cooling tower that consumes a significant amount of energy to operate, and hybrid GHPs can expand the market by allowing reduced GHX footprint in both heating- and cooling-dominated climates. The design tool allows for the straight-forward design of innovative GHP systems that currently pose a significant design challenge. The project lays the foundations for proper and reliable design of hybrid GHP systems, overcoming a series of difficult and cumbersome steps without the use of a system simulation approach, and without an automated optimization scheme. As new technologies and design concepts emerge, sophisticated design tools and methodologies must accompany them and be made usable for practitioners. Lack of reliable design tools results in reluctance of practitioners to implement more complex systems. A menu-driven software tool for the design of hybrid solar GHP systems is

  18. Proteome analysis of leaves of the desiccation-tolerant grass, sporobolus stapfianus, in response to desiccation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sporobolus stapfianus is a resurrection grass native to South Africa which can tolerate the complete drying of its vegetative tissue structure; i.e., desiccation, and recover fully within hours of rewetting. Gene expression studies have demonstrated that the grass employs a strategy of gene inductio...

  19. A desiccant dehumidifier for electric vehicle heating

    SciTech Connect

    Aceves, S.M.; Smith, J.R.

    1996-09-01

    Vehicle heating requires a substantial amount of energy. Engines in conventional cars produce enough waste heat to provide comfort heating and defogging/defrosting, even under very extreme conditions. Electric vehicles (EVs), however, generate little waste heat. Using battery energy for heating may consume a substantial fraction of the energy storage capacity, reducing the vehicle range, which is one of the most important parameters in determining EV acceptability. Water vapor generated by the vehicle passengers is in large part responsible for the high heating loads existing in vehicles. In cold climates, the generation of water vapor inside the car may result in water condensation on the windows, diminishing visibility. Two strategies are commonly used to avoid condensation on windows: windows are kept warm, and a large amount of ambient air is introduced in the vehicle. Either strategy results in a substantial heating load. These strategies are often used in combination, and a trade-off exists between them. If window temperature is decreased, ventilation rate has to be increased. Reducing the ventilation rate requires an increase of the temperature of the windows to prevent condensation. An alternative solution is a desiccant dehumidifier, which adsorbs water vapor generated by the passengers. Window temperatures and ventilation rates can then be reduced, resulting in a substantially lower heating load. This paper explores the dehumidifier heating concept. The first part shows the energy savings that could be obtained by using this technology. The second part specifies the required characteristics and dimensions of the system. The results indicate that the desiccant system can reduce the steady-state heating load by 60% or more under typical conditions. The reduction in heating load is such that waste heat may be enough to provide the required heating under most ambient conditions. Desiccant system dimensions and weight appear reasonable for packaging in an EV.

  20. Streptococcus pneumoniae Is Desiccation Tolerant and Infectious upon Rehydration

    PubMed Central

    Walsh, Rebecca L.; Camilli, Andrew

    2011-01-01

    ABSTRACT Streptococcus pneumoniae (pneumococcus) is a frequent colonizer of the nasopharynx and one of the leading causative agents of otitis media, pneumonia, and meningitis. The current literature asserts that S. pneumoniae is transmitted person to person via respiratory droplets; however, environmental surfaces (fomites) have been linked to the spread of other respiratory pathogens. Desiccation tolerance has been to shown to be essential for long-term survival on dry surfaces. This study investigated the survival and infectivity of S. pneumoniae following desiccation under ambient conditions. We recovered viable bacteria after all desiccation periods tested, ranging from 1 h to 4 weeks. Experiments conducted under nutrient limitation indicate that desiccation is a condition separate from starvation. Desiccation of an acapsular mutant and 15 different clinical isolates shows that S. pneumoniae desiccation tolerance is independent of the polysaccharide capsule and is a species-wide phenomenon, respectively. Experiments demonstrating that nondesiccated and desiccated S. pneumoniae strains colonize the nasopharynx at comparable levels, combined with their ability to survive long-term desiccation, suggest that fomites may serve as alternate sources of pneumococcal infection. PMID:21610120

  1. Experimental study on performance of celdek packed liquid desiccant dehumidifier

    NASA Astrophysics Data System (ADS)

    Kumar, Rakesh; Asati, A. K.

    2015-10-01

    Dehumidifier is the main component of liquid desiccant dehumidification system. Effect of the inlet parameters on various outlet parameters of the dehumidifier is studied in the present paper with structured pads as packing material and calcium chloride as liquid desiccant to process the air. The outlet parameters are change in specific humidity, mass transfer coefficient, moisture removal rate, air temperature, solution temperature, effectiveness and the corresponding inlet process parameters; mass flow rate of air, temperature of air, temperature and flow rate of desiccant solution. It is observed that mass transfer coefficient and moisture removal rate increase with increasing mass flow rate of the air and desiccant while these parameters decrease with increasing temperature of air and desiccant solution. Dehumidifier effectiveness gets increased with increasing solution flow rate. The present investigations are compared with the results of the researchers in the past.

  2. Desiccation resistance in four Drosophila species: sex and population effects.

    PubMed

    Matzkin, Luciano M; Watts, Thomas D; Markow, Therese A

    2007-01-01

    Desiccation resistance and body mass were measured in multiple populations of each of four species of Drosophila: two desert endemic species (D. nigrospiracula and D. mojavensis), and two with more widespread distributions (D. melanogaster and D. pseudoobscura). While flies from the desert species were more desiccation tolerant, there was, in certain cases, significant variation in desiccation resistance among populations of the same species. A significant difference in desiccation resistance was observed between the sexes, females were more resistant than males, but this relationship was reversed when taking into account body mass differences between the sexes. The degree of observed within-species variability demonstrates that studies focusing upon differences between species can produce different conclusions if they rely on observations for only single populations of a given species. Our data also suggest the existence of multiple mechanisms for desiccation resistance. PMID:18836314

  3. Design, fabrication, testing and delivery of a solar collector

    NASA Technical Reports Server (NTRS)

    Sims, W. H.; Ballheim, R. W.; Bartley, S. M.; Smith, G. W.

    1976-01-01

    A two phase program encompassing the redesign and fabrication of a solar collector which is low in cost and aesthetically appealing is described. Phase one work reviewed the current collector design and developed a low-cost design based on specific design/performance/cost requirements. Throughout this phase selected collector component materials were evaluated by testing and by considering cost, installation, maintainability and durability. The resultant collector design was composed of an absorber plate, insulation, frame, cover, desiccant and sealant. In Phase two, three collector prototypes were fabricated and evaluated for both nonthermal and thermal characteristics. Tests included static load tests of covers, burst pressure tests of absorber plates, and tests for optical characteristics of selective absorber plate coatings. The three prototype collectors were shipped to Marshall Space Flight Center for use in their solar heating and cooling test facility.

  4. Effect of supply/regeneration section area ratio on the performance of desiccant wheels in hot and humid climates: an experimental investigation

    NASA Astrophysics Data System (ADS)

    Zendehboudi, Alireza; Esmaeili, Hossein

    2016-06-01

    Desiccant cooling system is a suitable alternative option for conventional cooling system in humid climates. It is an environmental protection technique for cooling buildings. This study has investigated the effect of supply/regeneration section area ratio on the performance of desiccant wheels in hot and humid climates, using Silica Gel (WSG) and Molecular Sieve (LT3) desiccants. To this end, some parameters such as outlet air humidity ratio, process removed moisture, process outlet temperature, reactivation outlet temperature and reactivation outlet moisture have been examined as a function of rotational speed and inlet air humidity ratio in 1:3, 1:2 and 1:1 split. In this study, desiccant materials are regenerated using a constant regeneration temperature of 80 °C, wheel rotation speed range of 4-12 RPH (revolutions per hour) and variable humidity. The results show that a rise in area ratio causes an increase in process removed moisture, process outlet temperature, reactivation outlet temperature and a drop in reactivation outlet moisture and outlet humidity ratio of process air.

  5. Experimental and numerical investigations on the performance of dehumidifying desiccant beds composed of silica-gel and thermal energy storage particles

    NASA Astrophysics Data System (ADS)

    Rady, M. A.

    2009-03-01

    Enhanced efficiency of the adsorption process in the dehumidifier is a key element for improved performance of desiccant cooling systems. Due to the exothermic nature of the adsorption process, the dehumidification and cooling capacity are limited by significant temperature changes in the adsorption column. In the present study, the effects of integration of sensible and latent heat storage particles in the desiccant bed for in situ management of released adsorption heat are investigated. For this purpose, column experiments are performed using an initially dry granular bed made of silica-gel particles or a homogeneous mixture of silica gel and inert sensible or latent heat storage particles. The packed bed is subject to a sudden uniform air flow at selected values of temperature and humidity. Also, a packed bed numerical model is developed that includes the coupled non-equilibrium heat and moisture transfer in the solid and gas phases. Investigations of the heat and mass transfer characteristics are reported using the composite structure and the results are compared with the base case of simple silica gel bed. Improved desiccant cooling system performance can be obtained by appropriate adjustment of desiccant cycle operation and proper choice of the volume ratio of thermal energy storage particles.

  6. Maintaining gas cooling equipment

    SciTech Connect

    Rector, J.D.

    1997-05-01

    An often overlooked key to satisfactory operation and longevity of any mechanical device is proper operation and maintenance in accordance with the manufacturer`s written instructions. Absorption chillers, although they use a different technology than the more familiar vapor compression cycle to produce chilled water, operate successfully in a variety of applications if operated and maintained properly. Maintenance procedures may be more frequent than those required for vapor compression chillers, but they are also typically less complex. The goal of this article is to describe the basic operation of an absorption chiller to provide an understanding of the relatively simple tasks required to keep the machine operating at maximum efficiency for its design life and beyond. A good starting point is definitions. Gas cooling equipment is generally defined as alternative energy, non-electric cooling products. This includes absorption chillers, engine-drive chillers and packaged desiccant units, among others. Natural gas combustion drives the equipment.

  7. Desiccation stress induces developmental heterochrony in Drosophila melanogaster.

    PubMed

    Thorat, Leena; Oulkar, Dasharath P; Banerjee, Kaushik; Nath, Bimalendu B

    2016-09-01

    Stressful environments are known to perturb developmental patterns in insects. In the purview of desiccation as a stressor, relatively little is known about the developmental consequences linked with desiccation tolerance. In this study, we have particularly focused on the exploration of the temporal profile of postembryonic development in response to desiccation exposure in Drosophila melanogaster and the associated trade-offs. We document a correlation between variations in 20-hydroxyecdysone levels and the altered timing of metamorphic events during the life cycle. Following desiccation, we observed an extension in the larval longevity whereas the duration of the pupal and adult stages was significantly shortened. Alternately, feeding of 20-hydroxyecdysone apparently led to the restoration of the normal temporal pattern of development in the desiccated group. In spite of the desiccation-responsive heterochronic shifts in development, the overall lifespan post recovery remained almost unaltered among the desiccated and undesiccated groups suggesting plasticity in developmental control. This observation reminisces 'canalization-like' phenomenon that buffers alterations in the overall lifespan. We thus identified a desiccationresponsive period in the lifespan of D. melanogaster during which variations in ecdysone levels are capable to alter the temporal course of development. PMID:27581925

  8. Effect of desiccant isotherm on the design parameters of desiccant wheel

    NASA Astrophysics Data System (ADS)

    Yadav, Laxmikant; Yadav, Ankit; Dabra, Vishal; Yadav, Avadhesh

    2014-01-01

    A one dimensional mathematical model is developed to optimize the design parameters of desiccant wheel. The result shows that after some value of design parameters, change in moisture removal is negligible. The optimum isotherm shape should be R = 0.1. At this isotherm optimum value of wheel length, and channel pitch should be in the range of 0.2-0.25 and 0.003-0.004 m respectively.

  9. An investigation of the acceptance of solar heating and cooling in the housing industry in New Mexico

    NASA Technical Reports Server (NTRS)

    Lundahl, C. R.; Scott, J. C.; Dennis, D. M.

    1976-01-01

    A data base of information relating to the acceptability of solar-energy technology in the New Mexican housing industry was developed. Topics examined include: (1) the factors which influence the adoption of solar-energy systems in the New Mexican housing industry; (2) the degree of acceptability of various solar factors among New Mexican consumers, architects, contractors, financiers, energy suppliers, and governmental officials; and (3) the current attitudes toward the acceptability of solar energy factors in the New Mexican housing industry.

  10. Solid desiccant dehumidification systems for residential applications

    NASA Astrophysics Data System (ADS)

    Marciniak, T. J.; Grolmes, M. A.; Epstein, M.

    1985-03-01

    It is shown that gas regenerated desiccant dehumidifiers (GRDD) can be economically superior to vapor compression units in the hot, humid climates of the southeast and south. Altough the first cost of a GRDD unit is significantly higher than a vapor compression dehumidifier, reduced operating costs and savings in the installed cost of smaller air-conditioning units can provide an economic means for effective humidity control. The economic benefits are dependent upon: (1) the number of hours of dehumidifier operation per year; and (2) electricity and natural gas cost differentials. Of secondary importance is the coefficient of performance (COP) of the units. Recommendations for additional research and development for a commercial GRDD product line are outlined.

  11. Thermodynamic performance of a hybrid air cycle refrigeration system using a desiccant rotor

    NASA Astrophysics Data System (ADS)

    Hwang, Kyudae; Song, Chan Ho; Kim, Sung Ki; Saito, Kiyoshi; Kawai, Sunao

    2013-03-01

    Due to the concern on global warming, the demand for a system using natural refrigerant is increasing and many researches have been devoted to develop systems with natural refrigerants. Among natural refrigerant systems, an air cycle system has emerged as one of alternatives of Freon gas system due to environmentally friendly feature in spite of the inherent low efficiency. To overcome the technical barrier, this study proposed combination of multiple systems as a hybrid cycle to achieve higher efficiency of an air cycle system. The hybrid air cycle adopts a humidity control units such as an adsorber and a desorber to obtain the cooling effect from latent heat as well as sensible heat. To investigate the efficacy of the hybrid air cycle, the cooling performance of a hybrid air cycle is investigated analytically and experimentally. From the simulation result, it is found that COP of the hybrid air cycle is two times higher than that of the conventional air cycle. The experiments are conducted on the performance of the desiccant system according to the rotation speed in the system and displayed the feasibility of the key element in the hybrid air cycle system. From the results, it is shown that the system efficiency can be enhanced by utilization of the exhausted heat through the ambient heat exchanger with advantage of controlling the humidity by the desiccant rotor.

  12. The relationship between water binding and desiccation tolerance in tissues

    NASA Technical Reports Server (NTRS)

    Vertucci, C. W.; Leopold, A. C.

    1987-01-01

    In an effort to define the nature of desiccation tolerance, a comparison of the water sorption characteristics was made between tissues that were resistant and tissues that were sensitive to desiccation. Water sorption isotherms were constructed for germinated and ungerminated soybean axes and also for fronds of several species of Polypodium with varying tolerance to dehydration. The strength of water binding was determined by van't Hoff as well as D'Arcy/Watt analyses of the isotherms at 5, 15, and/or 25 degrees C. Tissues which were sensitive to desiccation had a poor capacity to bind water tightly. Tightly bound water can be removed from soybean and pea seeds by equilibration at 35 degrees C over very low relative humidities; this results in a reduction in the viability of the seed. We suggest that region 1 water (i.e. water bound with very negative enthalpy values) is an important component of desiccation tolerance.

  13. Active-solar-energy-system materials research priorities

    SciTech Connect

    Herzenberg, S.A.; Hien, L.K.; Silberglitt, R.

    1983-01-01

    THis report describes and prioritizes materials research alternatives to improve active solar heating and cooling system cost-effectiveness. Materials research areas analyzed are (polymer) glazings, heat mirrors, (selective) absorber surfaces, absorber adhesives, absorber substrates, fluids, thermal storage materials, and desiccants. Three classes of solar collectors are considered in the cost-effectiveness analysis: medium-temperature flat-plate collectors (operating temperature, 70/sup 0/C); high-temperature flat-plate collectors (operating temperature, 70 to 120/sup 0/C); and evacuated tubes (operating temperature 70 to 230/sup 0/C). We found the highest priority for medium-temperature flat-plate collectors to be research on polymeric materials to improve performance and durability characteristics. For the high-temperature, flat-plate collectors and evacuated tubes, heat mirror and selective absorber research is the highest priority. Research on storage materials, fluids, and desiccants is of relatively low priority for improving cost-effectiveness in all cases. The highest priority materials research areas identified include: optical properties and degradation of transparent conducting oxide heat mirrors and thickness insensitive selective paints; uv and thermal stabilization of polymeric glazing materials; and systems analysis of integrated polymeric collectors.

  14. Liquid Desiccant in Air Conditioners: Nano-Engineered Porous Hollow Fiber Membrane-Based Air Conditioning System

    SciTech Connect

    2010-09-02

    BEETIT Project: UTRC is developing an air conditioning system that is optimized for use in warm and humid climates. UTRC’s air conditioning system integrates a liquid drying agent or desiccant and a traditional vapor compression system found in 90% of air conditioners. The drying agent reduces the humidity in the air before it is cooled, using less energy. The technology uses a membrane as a barrier between the air and the liquid salt stream allowing only water vapor to pass through and not the salt molecules. This solves an inherent problem with traditional liquid desiccant systems—carryover of the liquid drying agent into the conditioned air stream—which eliminates corrosion and health issues

  15. Vehicle cabin cooling system for capturing and exhausting heated boundary layer air from inner surfaces of solar heated windows

    DOEpatents

    Farrington, Robert B.; Anderson, Ren

    2001-01-01

    The cabin cooling system includes a cooling duct positioned proximate and above upper edges of one or more windows of a vehicle to exhaust hot air as the air is heated by inner surfaces of the windows and forms thin boundary layers of heated air adjacent the heated windows. The cabin cooling system includes at least one fan to draw the hot air into the cooling duct at a flow rate that captures the hot air in the boundary layer without capturing a significant portion of the cooler cabin interior air and to discharge the hot air at a point outside the vehicle cabin, such as the vehicle trunk. In a preferred embodiment, the cooling duct has a cross-sectional area that gradually increases from a distal point to a proximal point to the fan inlet to develop a substantially uniform pressure drop along the length of the cooling duct. Correspondingly, this cross-sectional configuration develops a uniform suction pressure and uniform flow rate at the upper edge of the window to capture the hot air in the boundary layer adjacent each window.

  16. Hydraulic conductivity of desiccated geosynthetic clay liners

    SciTech Connect

    Boardman, B.T.; Daniel, D.E.

    1996-03-01

    Large-scale tests were performed to determine the effect of a cycle of wetting and drying on the hydraulic conductivity of several geosynthetic clay liners (GCLs). The GCLs were covered with 0.6 m of pea gravel and permeated with water. After steady seepage had developed, the water was drained away, and the GCL was desiccated by circulating heated air through the overlying gravel. The drying caused severe cracking in the bentonite component of the GCLs. The GCLs were again permeated with water. As the cracked bentonite hydrated and swelled, the hydraulic conductivity slowly decreased from an initially high value. The long-term, steady value of hydraulic conductivity after the wetting and drying cycle was found to be essentially the same as the value for the undesiccated GCL. It is concluded that GCLs possess the ability to self-heal after a cycle of wetting and drying, which is important for applications in which there may be alternate wetting and drying of a hydraulic barrier (e.g. within a landfill final cover).

  17. The modern office environment desiccates the eyes?

    PubMed

    Wolkoff, P; Nøjgaard, J K; Franck, C; Skov, P

    2006-08-01

    Eye irritation is a common complaint in the office environment. The purpose of this overview is to merge knowledge within indoor air science, ophthalmology, and occupational health to promote understanding eye irritation symptomatology, the cause of which is still partly unknown. High periocular relative humidity appears to protect the pre-corneal tear film against desiccation and sensory irritating pollutants and reduces the development of eye irritation symptoms. This is particularly relevant for intensive computer work, where the pre-corneal tear film is altered resulting in dry spot formation and eye dryness, in addition to enhanced susceptibility towards sensory irritating pollutants. The workplace, thermal conditions, and work schedule (including breaks) should be planned in such a way to help maintain a normal eye blink frequency to minimize alterations of the pre-corneal tear film. The role of relative humidity on eye irritation symptoms should not be underestimated. Multiple short breaks are justified by the beneficial effect on the pre-corneal tear film. In addition, longer breaks in tasks, which require demanding visual work, should be considered. In addition, air temperature as well as certain alkene oxidation products by ozone may worsen eye irritation symptoms, but the latter factor may be smaller at higher relative humidity. PMID:16842606

  18. Developing sporophytes transition from an inducible to a constitutive ecological strategy of desiccation tolerance in the moss Aloina ambigua: effects of desiccation on fitness

    PubMed Central

    Stark, Lloyd R.; Brinda, John C.

    2015-01-01

    Background and Aims Two ecological strategies of desiccation tolerance exist in plants, constitutive and inducible. Because of difficulties in culturing sporophytes, very little is known about desiccation tolerance in this generation and how desiccation affects sexual fitness. Methods Cultured sporophytes and vegetative shoots from a single genotype of the moss Aloina ambigua raised in the laboratory were tested for their strategy of desiccation tolerance by desiccating the shoot–sporophyte complex and vegetative shoots at different intensities, and comparing outcomes with those of undried shoot–sporophyte complexes and vegetative shoots. By using a dehardened clonal line, the effects of field, age and genetic variance among plants were removed. Key Results The gametophyte and embryonic sporophyte were found to employ a predominantly inducible strategy of desiccation tolerance, while the post-embryonic sporophyte was found to employ a moderately constitutive strategy of desiccation tolerance. Further, desiccation reduced sporophyte fitness, as measured by sporophyte mass, seta length and capsule size. However, the effects of desiccation on sporophyte fitness were reduced if the stress occurred during embryonic development as opposed to postembryonic desiccation. Conclusions The effects of desiccation on dehardened sporophytes of a bryophyte are shown for the first time. The transition from one desiccation tolerance strategy to the other in a single structure or generation is shown for only the second time in plants and for the first time in bryophytes. Finding degrees of inducible strategies of desiccation tolerance in different life phases prompts the formulation of a continuum hypothesis of ecological desiccation tolerance in mosses, where desiccation tolerance is not an either/or phenomenon, but varies in degree along a gradient of ecological inducibility. PMID:25578378

  19. The effect of multiple particle sizes on cooling rates of chondrules produced in large-scale shocks in the solar nebula

    NASA Astrophysics Data System (ADS)

    Morris, Melissa A.; Weidenschilling, Stuart J.; Desch, Steven J.

    2016-05-01

    Chondrules represent one of the best probes of the physical conditions and processes acting in the early solar nebula. Proposed chondrule formation models are assessed based on their ability to match the meteoritic evidence, especially experimental constraints on their thermal histories. The model most consistent with chondrule thermal histories is passage through shock waves in the solar nebula. Existing models of heating by shocks generally yield a good first-order approximation to inferred chondrule cooling rates. However, they predict prolonged heating in the preshock region, which would cause volatile loss and isotopic fractionation, which are not observed. These models have typically included particles of a single (large) size, i.e., chondrule precursors, or at most, large particles accompanied by micron-sized grains. The size distribution of solids present during chondrule formation controls the opacity of the affected region, and significantly affects the thermal histories of chondrules. Micron-sized grains evaporate too quickly to prevent excessive heating of chondrule precursors. However, isolated grains in chondrule-forming regions would rapidly coagulate into fractal aggregates. Preshock heating by infrared radiation from the shock front would cause these aggregates to melt and collapse into intermediate-sized (tens of microns) particles. We show that inclusion of such particles yields chondrule cooling rates consistent with petrologic and isotopic constraints.

  20. Research and Development of a Small-Scale Adsorption Cooling System

    NASA Astrophysics Data System (ADS)

    Gupta, Yeshpal

    The world is grappling with two serious issues related to energy and climate change. The use of solar energy is receiving much attention due to its potential as one of the solutions. Air conditioning is particularly attractive as a solar energy application because of the near coincidence of peak cooling loads with the available solar power. Recently, researchers have started serious discussions of using adsorptive processes for refrigeration and heat pumps. There is some success for the >100 ton adsorption systems but none exists in the <10 ton size range required for residential air conditioning. There are myriad reasons for the lack of small-scale systems such as low Coefficient of Performance (COP), high capital cost, scalability, and limited performance data. A numerical model to simulate an adsorption system was developed and its performance was compared with similar thermal-powered systems. Results showed that both the adsorption and absorption systems provide equal cooling capacity for a driving temperature range of 70--120 ºC, but the adsorption system is the only system to deliver cooling at temperatures below 65 ºC. Additionally, the absorption and desiccant systems provide better COP at low temperatures, but the COP's of the three systems converge at higher regeneration temperatures. To further investigate the viability of solar-powered heat pump systems, an hourly building load simulation was developed for a single-family house in the Phoenix metropolitan area. Thermal as well as economic performance comparison was conducted for adsorption, absorption, and solar photovoltaic (PV) powered vapor compression systems for a range of solar collector area and storage capacity. The results showed that for a small collector area, solar PV is more cost-effective whereas adsorption is better than absorption for larger collector area. The optimum solar collector area and the storage size were determined for each type of solar system. As part of this dissertation

  1. The limits and frontiers of desiccation-tolerant life.

    PubMed

    Alpert, Peter

    2005-11-01

    Drying to equilibrium with the air is lethal to most species of animals and plants, making drought (i.e., low external water potential) a central problem for terrestrial life and a major cause of agronomic failure and human famine. Surprisingly, a wide taxonomic variety of animals, microbes, and plants do tolerate complete desiccation, defined as water content below 0.1 g H(2)O g(-1) dry mass. Species in five phyla of animals and four divisions of plants contain desiccation-tolerant adults, juveniles, seeds, or spores. There seem to be few inherent limits on desiccation tolerance, since tolerant organisms can survive extremely intense and prolonged desiccation. There seems to be little phylogenetic limitation of tolerance in plants but may be more in animals. Physical constraints may restrict tolerance of animals without rigid skeletons and to plants shorter than 3 m. Physiological constraints on tolerance in plants may include control by hormones with multiple effects that could link tolerance to slow growth. Tolerance tends to be lower in organisms from wetter habitats, and there may be selection against tolerance when water availability is high. Our current knowledge of limits to tolerance suggests that they pose few obstacles to engineering tolerance in prokaryotes and in isolated cells and tissues, and there has already been much success on this scientific frontier of desiccation tolerance. However, physical and physiological constraints and perhaps other limits may explain the lack of success in extending tolerance to whole, desiccation-sensitive, multicellular animals and plants. Deeper understanding of the limits to desiccation tolerance in living things may be needed to cross this next frontier. PMID:21676818

  2. Insect capa neuropeptides impact desiccation and cold tolerance

    PubMed Central

    Terhzaz, Selim; Teets, Nicholas M.; Cabrero, Pablo; Henderson, Louise; Ritchie, Michael G.; Nachman, Ronald J.; Dow, Julian A. T.; Denlinger, David L.; Davies, Shireen-A.

    2015-01-01

    The success of insects is linked to their impressive tolerance to environmental stress, but little is known about how such responses are mediated by the neuroendocrine system. Here we show that the capability (capa) neuropeptide gene is a desiccation- and cold stress-responsive gene in diverse dipteran species. Using targeted in vivo gene silencing, physiological manipulations, stress-tolerance assays, and rationally designed neuropeptide analogs, we demonstrate that the Drosophila melanogaster capa neuropeptide gene and its encoded peptides alter desiccation and cold tolerance. Knockdown of the capa gene increases desiccation tolerance but lengthens chill coma recovery time, and injection of capa peptide analogs can reverse both phenotypes. Immunohistochemical staining suggests that capa accumulates in the capa-expressing Va neurons during desiccation and nonlethal cold stress but is not released until recovery from each stress. Our results also suggest that regulation of cellular ion and water homeostasis mediated by capa peptide signaling in the insect Malpighian (renal) tubules is a key physiological mechanism during recovery from desiccation and cold stress. This work augments our understanding of how stress tolerance is mediated by neuroendocrine signaling and illustrates the use of rationally designed peptide analogs as agents for disrupting protective stress tolerance. PMID:25730885

  3. Using liquid desiccant as a regenerable filter for capturing and deactivating contaminants

    DOEpatents

    Slayzak, Steven J.; Anderson, Ren S.; Judkoff, Ronald D.; Blake, Daniel M.; Vinzant, Todd B.; Ryan, Joseph P.

    2007-12-11

    A method, and systems for implementing such method, for purifying and conditioning air of weaponized contaminants. The method includes wetting a filter packing media with a salt-based liquid desiccant, such as water with a high concentration of lithium chloride. Air is passed through the wetted filter packing media and the contaminants in are captured with the liquid desiccant while the liquid desiccant dehumidifies the air. The captured contaminants are then deactivated in the liquid desiccant, which may include heating the liquid desiccant. The liquid desiccant is regenerated by applying heat to the liquid desiccant and then removing moisture. The method includes repeating the wetting with the regenerated liquid desiccant which provides a regenerable filtering process that captures and deactivates contaminants on an ongoing basis while also conditioning the air. The method may include filtration effectiveness enhancement by electrostatic or inertial means.

  4. Towards a systems-based understanding of plant desiccation tolerance.

    PubMed

    Moore, John P; Le, Ngoc Tuan; Brandt, Wolf F; Driouich, Azeddine; Farrant, Jill M

    2009-02-01

    Vegetative desiccation tolerance occurs in a unique group of species termed 'resurrection plants'. Here, we review the molecular genetic, physiological, biochemical, ultrastructural and biophysical studies that have been performed on a variety of resurrection plants to discover the mechanisms responsible for their tolerance. Desiccation tolerance in resurrection plants involves a combination of molecular genetic mechanisms, metabolic and antioxidant systems as well as macromolecular and structural stabilizing processes. We propose that a systems-biology approach coupled with multivariate data analysis is best suited to unraveling the mechanisms responsible for plant desiccation tolerance, as well as their integration with one another. This is of particular relevance to molecular biological engineering strategies for improving plant drought tolerance in important crop species, such as maize (Zea mays) and grapevine (Vitis vinifera). PMID:19179102

  5. Performance of Desiccant Particle Dispersion Type Air Conditioning System

    NASA Astrophysics Data System (ADS)

    Hatano, Hiroyuki; Suzuki, Koichi; Kojima, Hiromitsu

    An investigation of desiccant air conditioning system is performed to demonstrate its performance in a dispersed desiccant particle systems, based on its higher gas solid contacting efficiency and isothermal dehumidification. Particle dispersion is achieved using the risers of a circulating fluidized bed, CFB, or of a pneumatic conveyer. The risers used for dehumidification are 1390 mm in height and 22 mm in diameter. The former is used to evaluate the overall dehumidification performance and the latter is used to measure the axial humidity distribution under 0.88 m/s of a superficial air velocity. Based on the results of the overall performance by changing solid loading rates, Gs, from 0.4 kg/m2s up to 6 kg/m2s, desiccant particle dispersion shows higher performance in dehumidification, while axial humidity distribution shows very rapid adsorption rate in the entrance zone of the riser. Removal of adsorption heat accelerates dehumidification rate compared to the adiabatic process.

  6. Function of desiccate in gustatory sensilla of drosophila melanogaster

    PubMed Central

    Kawano, Takeshi; Ryuda, Masasuke; Matsumoto, Hitoshi; Ochiai, Masanori; Oda, Yasunori; Tanimura, Teiichi; Csikos, Gyorge; Moriya, Megumi; Hayakawa, Yoichi

    2015-01-01

    Desiccate (Desi), initially discovered as a gene expressing in the epidermis of Drosophila larvae for protection from desiccation stress, was recently found to be robustly expressed in the adult labellum; however, the function, as well as precise expression sites, was unknown. Here, we found that Desi is expressed in two different types of non-neuronal cells of the labellum, the epidermis and thecogen accessory cells. Labellar Desi expression was significantly elevated under arid conditions, accompanied by an increase in water ingestion by adults. Desi overexpression also promoted water ingestion. In contrast, a knockdown of Desi expression reduced feeding as well as water ingestion due to a drastic decrease in the gustatory sensillar sensitivity for all tested tastants. These results indicate that Desi helps protect insects from desiccation damage by not only preventing dehydration through the integument but also accelerating water ingestion via elevated taste sensitivities of the sensilla. PMID:26610608

  7. Traits underpinning desiccation resistance explain distribution patterns of terrestrial isopods.

    PubMed

    Dias, André T C; Krab, Eveline J; Mariën, Janine; Zimmer, Martin; Cornelissen, Johannes H C; Ellers, Jacintha; Wardle, David A; Berg, Matty P

    2013-07-01

    Predicted changes in soil water availability regimes with climate and land-use change will impact the community of functionally important soil organisms, such as macro-detritivores. Identifying and quantifying the functional traits that underlie interspecific differences in desiccation resistance will enhance our ability to predict both macro-detritivore community responses to changing water regimes and the consequences of the associated species shifts for organic matter turnover. Using path analysis, we tested (1) how interspecific differences in desiccation resistance among 22 northwestern European terrestrial isopod species could be explained by three underlying traits measured under standard laboratory conditions, namely, body ventral surface area, water loss rate and fatal water loss; (2) whether these relationships were robust to contrasting experimental conditions and to the phylogenetic relatedness effects being excluded; (3) whether desiccation resistance and hypothesized underlying traits could explain species distribution patterns in relation to site water availability. Water loss rate and (secondarily) fatal water loss together explained 90% of the interspecific variation in desiccation resistance. Our path model indicated that body surface area affects desiccation resistance only indirectly via changes in water loss rate. Our results also show that soil moisture determines isopod species distributions by filtering them according to traits underpinning desiccation resistance. These findings reveal that it is possible to use functional traits measured under standard conditions to predict soil biota responses to water availability in the field over broad spatial scales. Taken together, our results demonstrate an increasing need to generate mechanistic models to predict the effect of global changes on functionally important organisms. PMID:23224790

  8. Study of the application of solar chemical dehumidification system to wind tunnel facilities of NASA Lewis Research Center at Cleveland, Ohio

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Energy utilization and cost payback analyses were prepared for proposed modifications. A 50,000 CFM standard compact packaged solid desiccant dehumidifier utilizing high temperature hot water (HTHW) for desiccant regeneration was added. The HTHW is generated by utilizing solar energy and is stored in a storage tank. A steam boiler is provided as a back-up for the solar system. A 50,000 CFM standard compact package solid desiccant dehumidifier utilizing high temperature hot water (HTHW) for desiccant regeneration was added. The HTHW is generated by utilizing a steam boiler and a heat exchanger and is stored in a storage tank.

  9. Heat-activated cooling devices: A guidebook for general audiences

    SciTech Connect

    Wiltsee, G.

    1994-02-01

    Heat-activated cooling is refrigeration or air conditioning driven by heat instead of electricity. A mill or processing facility can us its waste fuel to air condition its offices or plant; using waste fuel in this way can save money. The four basic types of heat-activated cooling systems available today are absorption cycle, desiccant system, steam jet ejector, and steam turbine drive. Each is discussed, along with cool storage and biomass boilers. Steps in determining the feasibility of heat-activated cooling are discussed, as are biomass conversion, system cost and integration, permits, and contractor selection. Case studies are given.

  10. Parametric study of thermal storage containing rocks or fluid filled cans for solar heating and cooling, phase 2

    NASA Technical Reports Server (NTRS)

    Saha, H.

    1981-01-01

    The test data and an analysis of the heat transfer characteristics of a solar thermal energy storage bed utilizing water filled cans and standard bricks as energy storage medium are presented. This experimental investigation was initiated to find a usable heat intensive solar thermal storage device other than rock storage and water tank. Four different sizes of soup cans were stacked in a chamber in three different arrangements-vertical, horizontal, and random. Air is used as transfer medium for charging and discharge modes at three different mass flow rates and inlet air temperature respectively. These results are analyzed and compared, which show that a vertical stacking and medium size cans with Length/Diameter (L/D) ratio close to one have better average characteristics of heat transfer and pressure drop.

  11. Research Proposal for the Design and Engineering Phase of a Solar Heating and Cooling System Experiment at the Warner Robins Public Library, Warner Robins, Georgia. Submitted to the United States Energy Research and Development Administration.

    ERIC Educational Resources Information Center

    Phillips, Warren H.; And Others

    A number of reasons are advanced to include a solar heating and cooling experiment in a library building. The unique aspects of the experiment are to be a seasonally adjustable collector tilt and testing of a new generation of absorption air conditioners. After a brief description of the proposed experiment, the proposal contains forms filed by…

  12. NASA Microclimate Cooling Challenges

    NASA Technical Reports Server (NTRS)

    Trevino, Luis A.

    2004-01-01

    The purpose of this outline form presentation is to present NASA's challenges in microclimate cooling as related to the spacesuit. An overview of spacesuit flight-rated personal cooling systems is presented, which includes a brief history of cooling systems from Gemini through Space Station missions. The roles of the liquid cooling garment, thermal environment extremes, the sublimator, multi-layer insulation, and helmet visor UV and solar coatings are reviewed. A second section is presented on advanced personal cooling systems studies, which include heat acquisition studies on cooling garments, heat rejection studies on water boiler & radiators, thermal storage studies, and insulation studies. Past and present research and development and challenges are summarized for the advanced studies.

  13. Desiccation-crack-induced salinization in deep clay sediment

    NASA Astrophysics Data System (ADS)

    Baram, S.; Ronen, Z.; Kurtzman, D.; Külls, C.; Dahan, O.

    2013-04-01

    A study on water infiltration and solute transport in a clayey vadose zone underlying a dairy farm waste source was conducted to assess the impact of desiccation cracks on subsurface evaporation and salinization. The study is based on five years of continuous measurements of the temporal variation in the vadose zone water content and on the chemical and isotopic composition of the sediment and pore water in it. The isotopic composition of water stable isotopes (δ18O and δ2H) in water and sediment samples, from the area where desiccation crack networks prevail, indicated subsurface evaporation down to ~ 3.5 m below land surface, and vertical and lateral preferential transport of water, following erratic preferential infiltration events. Chloride (Cl-) concentrations in the vadose zone pore water substantially increased with depth, evidence of deep subsurface evaporation and down flushing of concentrated solutions from the evaporation zones during preferential infiltration events. These observations led to development of a desiccation-crack-induced salinization (DCIS) conceptual model. DCIS suggests that thermally driven convective air flow in the desiccation cracks induces evaporation and salinization in relatively deep sections of the subsurface. This conceptual model supports previous conceptual models on vadose zone and groundwater salinization in fractured rock in arid environments and extends its validity to clayey soils in semi-arid environments.

  14. Survival of methanogens during desiccation: implications for life on Mars.

    PubMed

    Kendrick, Michael G; Kral, Timothy A

    2006-08-01

    The relatively recent discoveries that liquid water likely existed on the surface of past Mars and that methane currently exists in the martian atmosphere have fueled the possibility of extant or extinct life on Mars. One possible explanation for the existence of the methane would be the presence of methanogens in the subsurface. Methanogens are microorganisms in the domain Archaea that can metabolize molecular hydrogen as an energy source and carbon dioxide as a carbon source and produce methane. One factor of importance is the arid nature of Mars, at least at the surface. If one is to assume that life exists below the surface, then based on the only example of life that we know, liquid water must be present. Realistically, however, that liquid water may be seasonal just as it is at some locations on our home planet. Here we report on research designed to determine how long certain species of methanogens can survive desiccation on a Mars soil simulant, JSC Mars-1. Methanogenic cells were grown on JSC Mars-1, transferred to a desiccator within a Coy anaerobic environmental chamber, and maintained there for varying time periods. Following removal from the desiccator and rehydration, gas chromatographic measurements of methane indicated survival for varying time periods. Methanosarcina barkeri survived desiccation for 10 days, while Methanobacterium formicicum and Methanothermobacter wolfeii were able to survive for 25 days. PMID:16916281

  15. Survival of Methanogens During Desiccation: Implications for Life on Mars

    NASA Astrophysics Data System (ADS)

    Kendrick, Michael G.; Kral, Timothy A.

    2006-08-01

    The relatively recent discoveries that liquid water likely existed on the surface of past Mars and that methane currently exists in the martian atmosphere have fueled the possibility of extant or extinct life on Mars. One possible explanation for the existence of the methane would be the presence of methanogens in the subsurface. Methanogens are microorganisms in the domain Archaea that can metabolize molecular hydrogen as an energy source and carbon dioxide as a carbon source and produce methane. One factor of importance is the arid nature of Mars, at least at the surface. If one is to assume that life exists below the surface, then based on the only example of life that we know, liquid water must be present. Realistically, however, that liquid water may be seasonal just as it is at some locations on our home planet. Here we report on research designed to determine how long certain species of methanogens can survive desiccation on a Mars soil simulant, JSC Mars-1. Methanogenic cells were grown on JSC Mars-1, transferred to a desiccator within a Coy anaerobic environmental chamber, and maintained there for varying time periods. Following removal from the desiccator and rehydration, gas chromatographic measurements of methane indicated survival for varying time periods. Methanosarcina barkeri survived desiccation for 10 days, while Methanobacterium formicicum and Methanothermobacter wolfeii were able to survive for 25 days.

  16. Desiccation-crack-induced salinization in deep clay sediment

    NASA Astrophysics Data System (ADS)

    Baram, S.; Ronen, Z.; Kurtzman, D.; Küells, C.; Dahan, O.

    2012-11-01

    A study on water infiltration and solute transport in a clayey vadose zone underlying a dairy farm waste source was conducted to assess the impact of desiccation cracks on subsurface evaporation and salinization. The study is based on five years of continuous measurements of the temporal variation in the vadose zone water-content and on the chemical and isotopic composition of the sediment and pore-water in it. The isotopic composition of water stable isotopes (δ18O and δ2H) in water and sediment samples, from the area where desiccation crack networks prevail, indicated subsurface evaporation down to ∼3.5 m below land surface, and vertical and lateral preferential transport of water, following erratic preferential infiltration events. Chloride (Cl-) concentrations in the vadose zone pore water substantially increased with depth, evidence of deep subsurface evaporation and down flushing of concentrated solutions from the evaporation zones during preferential infiltration events. These observations led to development of a Desiccation-Crack-Induced Salinization (DCIS) conceptual model. DCIS suggests that thermally driven convective air flow in the desiccation cracks induces evaporation and salinization in relatively deep sections of the subsurface. This conceptual model supports previous conceptual models on vadose zone and groundwater salinization in fractured rock in arid environments and extends its validity to clayey soils in semi-arid environments.

  17. REPLACEMENT HISTONES: A ROLE IN DESICCATION TOLERANCE IN MOSS?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Analysis of an expressed sequence tag (EST) cDNA library from the desiccation-tolerant moss, Tortula ruralis, identified a clone, RNP49, with strong sequence similarity to genes encoding histone, H3, a component of the core nucleosome in all eukaryotes. The RNP49 cDNA clone was produced using mRNA ...

  18. Transcriptional Response of Saccharomyces cerevisiae to Desiccation and Rehydration†

    PubMed Central

    Singh, Jatinder; Kumar, Deept; Ramakrishnan, Naren; Singhal, Vibha; Jervis, Jody; Garst, James F.; Slaughter, Stephen M.; DeSantis, Andrea M.; Potts, Malcolm; Helm, Richard F.

    2005-01-01

    A transcriptional analysis of the response of Saccharomyces cerevisiae strain BY4743 to controlled air-drying (desiccation) and subsequent rehydration under minimal glucose conditions was performed. Expression of genes involved in fatty acid oxidation and the glyoxylate cycle was observed to increase during drying and remained in this state during the rehydration phase. When the BY4743 expression profile for the dried sample was compared to that of a commercially prepared dry active yeast, strikingly similar expression changes were observed. The fact that these two samples, dried by different means, possessed very similar transcriptional profiles supports the hypothesis that the response to desiccation is a coordinated event independent of the particular conditions involved in water removal. Similarities between “stationary-phase-essential genes” and those upregulated during desiccation were also noted, suggesting commonalities in different routes to reduced metabolic states. Trends in extracellular and intracellular glucose and trehalose levels suggested that the cells were in a “holding pattern” during the rehydration phase, a concept that was reinforced by cell cycle analyses. Application of a “redescription mining” algorithm suggested that sulfur metabolism is important for cell survival during desiccation and rehydration. PMID:16332871

  19. Lessons on dehydration tolerance from desiccation tolerant plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Extremophiles: organisms that thrive (a relative term) in environments where conditions are such that the majority of organisms cannot survive. This is not strictly true if one is describing desiccation-tolerant plants, as other plants do grow around them, but it is certainly true that they can surv...

  20. Halophilic Archaea: Life with Desiccation, Radiation and Oligotrophy over Geological Times

    PubMed Central

    Stan-Lotter, Helga; Fendrihan, Sergiu

    2015-01-01

    Halophilic archaebacteria (Haloarchaea) can survive extreme desiccation, starvation and radiation, sometimes apparently for millions of years. Several of the strategies that are involved appear specific for Haloarchaea (for example, the formation of halomucin, survival in fluid inclusions of halite), and some are known from other prokaryotes (dwarfing of cells, reduction of ATP). Several newly-discovered haloarchaeal strategies that were inferred to possibly promote long-term survival—halomucin, polyploidy, usage of DNA as a phosphate storage polymer, production of spherical dormant stages—remain to be characterized in detail. More information on potential strategies is desirable, since evidence for the presence of halite on Mars and on several moons in the solar system increased interest in halophiles with respect to the search for extraterrestrial life. This review deals in particular with novel findings and hypotheses on haloarchaeal long-term survival. PMID:26226005