Sample records for heat storage medium

  1. Research on medium and high temperature solar heat storage materials

    NASA Technical Reports Server (NTRS)

    Heine, D.; Jucker, J.; Koch, D.; Krahling, H.; Supper, W.

    1979-01-01

    Characteristics of solar heat storage materials, preliminary tests in which melting and solidification characteristics are tested, and service life and cycling tests are reported. Various aspects of corrosion are discussed as well as decision about ultimate selection of materials. A program for storage and evaluation of data is included.

  2. Study on medium-temperature chemical heat storage using mixed hydroxides

    Microsoft Academic Search

    Yukitaka Kato; Rui Takahashi; Toshiya Sekiguchi; Junichi Ryu

    2009-01-01

    It was demonstrated that chemical heat storage materials mixed with metal hydroxides were capable of storing heat at medium temperatures of approximately 200–300°C. The performances of the developed materials were demonstrated in a thermo-balance and packed bed reactor. The mixed hydroxides can increase the operation heat storage temperature by changing the composition of mixed metal oxides in the material. Mg?Ni1??(OH)2, which

  3. HEATS: Thermal Energy Storage

    SciTech Connect

    None

    2012-01-01

    HEATS Project: The 15 projects that make up ARPA-E’s HEATS program, short for “High Energy Advanced Thermal Storage,” seek to develop revolutionary, cost-effective ways to store thermal energy. HEATS focuses on 3 specific areas: 1) developing high-temperature solar thermal energy storage capable of cost-effectively delivering electricity around the clock and thermal energy storage for nuclear power plants capable of cost-effectively meeting peak demand, 2) creating synthetic fuel efficiently from sunlight by converting sunlight into heat, and 3) using thermal energy storage to improve the driving range of electric vehicles (EVs) and also enable thermal management of internal combustion engine vehicles.

  4. Disposable heat storage unit

    SciTech Connect

    Hartz, M.E.

    1988-10-18

    This patent describes a single use, disposable, heat storage unit comprising a sealed pouch forming a wholly internal, sealed chamber having a predetermined maximum volume; and a particulate, fluent, dry, latent heat storage substance within the chamber, the volume of the substance within the chamber being sufficiently less than the predetermined maximum volume that the particles of the substance do not fill the chamber and are freely movable in all directions within the chamber, the substance having a predetermined heat of fusion temperature in excess of 100C, the pouch being formed of pliable, moisture resistant, thermal transfer material capable of withstanding without adverse consequences being heated to an initial temperature higher than the heat of fusion temperature of the substance. Thermal heat storage apparatus comprising a disposable container having walls of thermally insulating material forming a compartment; a single use, disposable, sealed, flexible pouch positioned within the compartment and formed of moisture resistant, heat transfer material, the pouch forming a wholly internal, sealed chamber having a maximum volume; a dry, particulate, fluent, latent head storage substance accommodated in the chamber, the volume of the substance within the chamber being sufficiently less than the maximum volume that the particles of the substance do not fill the chamber and are freely movable in all directions within the chamber, the substance having a heat of fusion temperature in excess of 100; the material of the wall and the material of the pouch being capable of withstanding without adverse consequences being heated to an initial temperature in excess of the heat of fusion temperature of the substance.

  5. Solar Energy: Heat Storage.

    ERIC Educational Resources Information Center

    Knapp, Henry H., III

    This module on heat storage is one of six in a series intended for use as supplements to currently available materials on solar energy and energy conservation. Together with the recommended texts and references (sources are identified), these modules provide an effective introduction to energy conservation and solar energy technologies. The module…

  6. Heat transfer of high thermal energy storage with heat exchanger for solar trough power plant

    Microsoft Academic Search

    Sarayooth Vaivudh; Wattanapong Rakwichian; Sirinuch Chindaruksa

    2008-01-01

    High temperature thermal energy storage was studied by a lab-scale cylindrical storage tank experiment. A heat exchanger of thermal energy storage is used for separating two fluids, storage medium, and heat transfer fluid (HTF). There are two types of pipe in the heat exchanger, a vertical straight pipe and a helical coiled pipe. The experimental results were validated with the

  7. Advanced solar thermal storage medium test data and analysis

    NASA Technical Reports Server (NTRS)

    Saha, H.

    1981-01-01

    A comparative study has been made of experimentally obtained heat transfer and heat storage characteristics of a solar thermal energy storage bed utilizing containerized water or phase change material (PCM) and rock or brick. It is shown that (1) containers with an L/D ratio of 0.80 and a mass/surface area ratio of 2.74 in a random stacking arrangement have the optimum heat transfer characteristics; and (2) vertical stacking has the least pressure drop across the test bed. It is also found that standard bricks with appropriate holes make an excellent storage medium.

  8. Solar heating thermal storage feasibility

    Microsoft Academic Search

    P. Joy; B. Shelpuk

    1976-01-01

    The relative technical and economic merits of various approaches to thermal energy storage for solar heating applications are reported in this paper. A solar heating system was computer modeled, including solar collectors, building demand, and conventional heating system. Several approaches to thermal energy storage including specific heating, phase change, and combinations of the two were modeled and run in the

  9. Low temperature latent heat thermal energy storage - Heat storage materials

    Microsoft Academic Search

    A. Abhat

    1983-01-01

    Heat-of-fusion storage materials for low temperature latent heat storage in the temperature range 0-120 C are reviewed. Organic and inorganic heat storage materials classified as paraffins, fatty acids, inorganic salt hydrates and eutectic compounds are considered. The melting and freezing behavior of the various substances is investigated using the techniques of Thermal Analysis and Differential Scanning Calorimetry. The importance of

  10. Active heat exchange thermal storage unit with pentaerythritol

    Microsoft Academic Search

    Y. Abe; M. Kamimoto; K. Kanari; T. Ozawa; R. Sakamoto; Y. Takahashi

    1984-01-01

    A latent thermal energy storage unit with pentaerythritol was developed, and in the storage unit an active heat transfer enhancement was performed. The phase change material, pentaerythritol, was mixed with a hydrocarbon heat transfer oil and this two-phase storage medium was stirred in a shell-coil type heat exchanger. Through the preliminary experiments in a glass vessel, a lab-scale storage unit

  11. Active heat exchange thermal storage unit with pentaerythritol

    SciTech Connect

    Abe, Y.; Kamimoto, M.; Kanari, K.; Ozawa, T.; Sakamoto, R.; Takahashi, Y.

    1984-08-01

    A latent thermal energy storage unit with pentaerythritol was developed, and in the storage unit an active heat transfer enhancement was performed. The phase change material, pentaerythritol, was mixed with a hydrocarbon heat transfer oil and this two-phase storage medium was stirred in a shell-coil type heat exchanger. Through the preliminary experiments in a glass vessel, a lab-scale storage unit of 1 kWh storage capacity was developed. The storage unit demonstrated the feature of latent thermal energy storage; constant-temperature output in both charge and discharge periods was observed.

  12. Characterization of Alkanes and Paraffin Waxes for Application as Phase Change Energy Storage Medium

    Microsoft Academic Search

    SYUKRI HIMRAN; ARYADI SUWONO; G. ALI MANSOORI

    1994-01-01

    Latent thermal energy storage is one of the favorable kinds of thermal energy storage methods considered for renewable energy source utilization, as in solar photothermal systems. Heat is stored mostly by means of the latent heat of phase change of the medium. The temperature of the medium remains more or less constant during the phase transition. A large number of

  13. Heat storage in alloy transformations

    NASA Technical Reports Server (NTRS)

    Birchenall, C. E.; Gueceri, S. I.

    1980-01-01

    The theory of eutectic transformation was examined to find guidelines to the best material combinations to examine. The heats of transformation were measured calorimetrically, and the volume changes of expanding solid mixtures and homogeneous liquid solutions, especially during the transformation between the two states at fixed temperature, were measured by changes in X-ray absorption. Heat flow models appropriate to storage in phase change materials were developed along with efficient calculating procedures so that the relative importance of the problems associated with energy storage density, heat conduction, and similar properties could be assessed.

  14. Quantum heat engine with continuum working medium

    E-print Network

    S. Li; H. Wang; Y. D. Sun; X. X. Yi

    2006-07-18

    We introduce a new quantum heat engine, in which the working medium is a quantum system with a discrete level and a continuum. Net work done by this engine is calculated and discussed. The results show that this quantum heat engine behaves like the two-level quantum heat engine in both the high-temperature and the low-temperature limits, but it operates differently in temperatures between them. The efficiency of this quantum heat engine is also presented and discussed.

  15. THERMOCHEMICAL HEAT STORAGE FOR CONCENTRATED; SOLAR POWER

    Microsoft Academic Search

    2011-01-01

    Thermal energy storage (TES) is an integral part of a concentrated solar power (CSP) system. It enables plant operators to generate electricity beyond on sun hours and supply power to the grid to meet peak demand. Current CSP sensible heat storage systems employ molten salts as both the heat transfer fluid and the heat storage media. These systems have an

  16. Heat storage in alloy transformations

    NASA Technical Reports Server (NTRS)

    Birchenall, C. E.; Gueceri, S. I.; Farkas, D.; Labdon, M. B.; Nagaswami, N.; Pregger, B.

    1981-01-01

    The feasibility of using metal alloys as thermal energy storage media was determined. The following major elements were studied: (1) identification of congruently transforming alloys and thermochemical property measurements; (2) development of a precise and convenient method for measuring volume change during phase transformation and thermal expansion coefficients; (3) development of a numerical modeling routine for calculating heat flow in cylindrical heat exchangers containing phase change materials; and (4) identification of materials that could be used to contain the metal alloys. Several eutectic alloys and ternary intermetallic phases were determined. A method employing X-ray absorption techniques was developed to determine the coefficients of thermal expansion of both the solid and liquid phases and the volume change during phase transformation from data obtained during one continuous experimental test. The method and apparatus are discussed and the experimental results are presented. The development of the numerical modeling method is presented and results are discussed for both salt and metal alloy phase change media.

  17. Olivine-based heat storage refractories

    NASA Astrophysics Data System (ADS)

    Gay, B. M.; Palmour, H., III; Cochrane, R. L.

    1981-03-01

    The processing properties and performance of special refractory shapes produced from olivine for prototype evaluations in heat storage furnaces are investigated. Heat storage furnaces and related consumer owned thermal storage units are energy conversion/storage devices of the sensible heat type. Their primary purpose is to permit electrical load leveling of large generating/distributing systems. Load-leveling enables power generating plants to operate more efficiency thus contributing to better overall energy utilization. The principal application for these ceramic thermal energy reservoirs is in home or business heating (furnaces, space heaters).

  18. Heat storage in alloy transformations

    NASA Technical Reports Server (NTRS)

    Birchenall, C. E.

    1980-01-01

    The feasibility of using metal alloys as thermal energy storage media was investigated. The elements selected as candidate media were limited to aluminum, copper, magnesium, silicon, zinc, calcium, and phosphorus on the basis of low cost and latent heat of transformation. Several new eutectic alloys and ternary intermetallic phases were determined. A new method employing X-ray absorption techniques was developed to determine the coefficients of thermal expansion of both the solid and liquid phases and the volume change during phase transformation. The method and apparatus are discussed and the experimental results are presented for aluminum and two aluminum-eutectic alloys. Candidate materials were evaluated to determine suitable materials for containment of the metal alloys. Graphite was used to contain the alloys during the volume change measurements. Silicon carbide was identified as a promising containment material and surface-coated iron alloys were also evaluated. System considerations that are pertinent if alloy eutectics are used as thermal energy storage media are discussed. Potential applications to solar receivers and industrial furnaces are illustrated schematically.

  19. Heat storage in alloy transformations

    NASA Astrophysics Data System (ADS)

    Birchenall, C. E.

    1980-04-01

    The feasibility of using metal alloys as thermal energy storage media was investigated. The elements selected as candidate media were limited to aluminum, copper, magnesium, silicon, zinc, calcium, and phosphorus on the basis of low cost and latent heat of transformation. Several new eutectic alloys and ternary intermetallic phases were determined. A new method employing X-ray absorption techniques was developed to determine the coefficients of thermal expansion of both the solid and liquid phases and the volume change during phase transformation. The method and apparatus are discussed and the experimental results are presented for aluminum and two aluminum-eutectic alloys. Candidate materials were evaluated to determine suitable materials for containment of the metal alloys. Graphite was used to contain the alloys during the volume change measurements. Silicon carbide was identified as a promising containment material and surface-coated iron alloys were also evaluated. System considerations that are pertinent if alloy eutectics are used as thermal energy storage media are discussed. Potential applications to solar receivers and industrial furnaces are illustrated schematically.

  20. Dish-mounted latent heat buffer storage

    NASA Technical Reports Server (NTRS)

    Manvi, R.

    1981-01-01

    Dish-mounted latent heat storage subsystems for Rankine, Brayton, and Stirling engines operating at 427 C, 816 C, and 816 C respectively are discussed. Storage requirements definition, conceptual design, media stability and compatibility tests, and thermal performance analyses are considered.

  1. Advanced solar thermal storage medium test data and analysis

    Microsoft Academic Search

    H. Saha

    1981-01-01

    A comparative study has been made of experimentally obtained heat transfer and heat storage characteristics of a solar thermal energy storage bed utilizing containerized water or phase change material (PCM) and rock or brick. It is shown that (1) containers with an L\\/D ratio of 0.80 and a mass\\/surface area ratio of 2.74 in a random stacking arrangement have the

  2. Adsorption solar heating and storage system

    Microsoft Academic Search

    Guerra

    1981-01-01

    A typical solar energy flat plate collector is disclosed whose volume is filled with a zeolite such as Linde Co.'s type 13x or lms type 4a. The zeolite bed provides a means of chemical storage of solar energy for sunless periods through its potential ''heat of adsorption''. During sunless hours, stored energy in the form of latent heat of adsorption

  3. Sulfuric acid-sulfur heat storage cycle

    DOEpatents

    Norman, John H. (LaJolla, CA)

    1983-12-20

    A method of storing heat is provided utilizing a chemical cycle which interconverts sulfuric acid and sulfur. The method can be used to levelize the energy obtained from intermittent heat sources, such as solar collectors. Dilute sulfuric acid is concentrated by evaporation of water, and the concentrated sulfuric acid is boiled and decomposed using intense heat from the heat source, forming sulfur dioxide and oxygen. The sulfur dioxide is reacted with water in a disproportionation reaction yielding dilute sulfuric acid, which is recycled, and elemental sulfur. The sulfur has substantial potential chemical energy and represents the storage of a significant portion of the energy obtained from the heat source. The sulfur is burned whenever required to release the stored energy. A particularly advantageous use of the heat storage method is in conjunction with a solar-powered facility which uses the Bunsen reaction in a water-splitting process. The energy storage method is used to levelize the availability of solar energy while some of the sulfur dioxide produced in the heat storage reactions is converted to sulfuric acid in the Bunsen reaction.

  4. Experimental Research on Solar Assisted Heat Pump Heating System with Latent Heat Storage

    E-print Network

    Han, Z.; Zheng, M.; Liu, W.; Wang, F.

    2006-01-01

    ICEBO2006, Shenzhen, China Re newable Energy Resources and a Greener Future Vol.VIII-2-3 Experimental Research on Solar Assisted Heat Pump Heating System with Latent Heat Storage Zongwei Han Maoyu Zheng Wei Liu Fang Wang...

  5. Thermodynamic Efficiency of Pumped Heat Electricity Storage

    NASA Astrophysics Data System (ADS)

    Thess, André

    2013-09-01

    Pumped heat electricity storage (PHES) has been recently suggested as a potential solution to the large-scale energy storage problem. PHES requires neither underground caverns as compressed air energy storage (CAES) nor kilometer-sized water reservoirs like pumped hydrostorage and can therefore be constructed anywhere in the world. However, since no large PHES system exists yet, and theoretical predictions are scarce, the efficiency of such systems is unknown. Here we formulate a simple thermodynamic model that predicts the efficiency of PHES as a function of the temperature of the thermal energy storage at maximum output power. The resulting equation is free of adjustable parameters and nearly as simple as the well-known Carnot formula. Our theory predicts that for storage temperatures above 400°C PHES has a higher efficiency than existing CAES and that PHES can even compete with the efficiencies predicted for advanced-adiabatic CAES.

  6. Thermodynamic efficiency of pumped heat electricity storage.

    PubMed

    Thess, André

    2013-09-13

    Pumped heat electricity storage (PHES) has been recently suggested as a potential solution to the large-scale energy storage problem. PHES requires neither underground caverns as compressed air energy storage (CAES) nor kilometer-sized water reservoirs like pumped hydrostorage and can therefore be constructed anywhere in the world. However, since no large PHES system exists yet, and theoretical predictions are scarce, the efficiency of such systems is unknown. Here we formulate a simple thermodynamic model that predicts the efficiency of PHES as a function of the temperature of the thermal energy storage at maximum output power. The resulting equation is free of adjustable parameters and nearly as simple as the well-known Carnot formula. Our theory predicts that for storage temperatures above 400?°C PHES has a higher efficiency than existing CAES and that PHES can even compete with the efficiencies predicted for advanced-adiabatic CAES. PMID:24074066

  7. Latent Heat Storage Materials and Systems: A Review

    Microsoft Academic Search

    S. D. Sharma; Kazunobu Sagara

    2005-01-01

    The use of a latent heat storage system using Phase Change Materials (PCM) is an effective way of storing thermal energy (solar energy, off-peak electricity, industrial waste heat) and has the advantages of high storage density and the isothermal nature of the storage process. It has been demonstrated that, for the development of a latent heat storage system, choice of

  8. A novel latent heat storage for solar space heating systems - Refrigerant storage

    NASA Astrophysics Data System (ADS)

    Sheridan, N. R.; Kaushik, S. C.

    1981-11-01

    This paper proposes a novel latent heat storage which is applicable to solar space heating systems. The device is similar to an absorption refrigerator and stores liquid refrigerant which is subsequently evaporated to release the latent heat. It will recover the energy in a heat pump mode for application to solar space heating systems which are seen to be more cost effective - and hence to have a better market potential - than space cooling systems.

  9. Assessment of energy storage technologies and systems. Phase 1: Electric storage heating, storage air conditioning, and storage hot water heaters

    Microsoft Academic Search

    J. G. Asbury; R. Giese; S. Nelson; L. Akridge; P. Graf; K. Heitner

    1976-01-01

    The commercial feasibility of thermal energy storage (TES) in buildings is analyzed. TES applications examined include storage electric (resistance) heating, storage air conditioning, and storage hot water heating. A system model, SIMSTOR, is employed to simulate TES-related effects upon daily and annual utility load profiles and to compare utility fuel and capital cost savings with TES-system costs. Case-study analyses of

  10. General characteristics of thermochemical heat storage

    Microsoft Academic Search

    Wentworth

    1985-01-01

    The research and development on thermochemical heat storage have focused on systems which operate at either a low temperature (approx. 100-150°C or 220-300°F) or a high temperature (approx. 350-500°C or 660-930°F). The low temperature systems are intended primarily for heating and cooling buildings and can be operated with high efficiency, double-glazed flat plate solar collectors or slightly concentrating collectors such

  11. SIMULATION OF A CENTRAL SOLAR HEATING SYSTEM WITH SEASONAL STORAGE IN KOREA

    Microsoft Academic Search

    Mo Chung; Jun-Un Park; Hyung-Kee Yoon

    1998-01-01

    A Central Solar Heating Plant with Seasonal Storage (CSHPSS), which is under construction in Korea, is simulated using TRNSYS to predict thermal performances and economic aspects. The system is located in Cheju Island, a far southern part of Korea, and consists of two arrays of collectors, a medium-sized storage tank, and two thermal loads. The loads are an office building

  12. Latent heat storage for solar energy systems - Transient simulation of refrigerant storage

    NASA Astrophysics Data System (ADS)

    Kaushik, S. C.

    1982-09-01

    This paper presents a brief review of the available latent heat storage systems for solar energy utilization. A new concept of latent heat storage of solar energy via the refrigerant-absorbent mass storage in absorption cycle heat pump systems used for solar space heating/cooling has been proposed and assessed thermodynamically. A computer modeling and numerical simulation study shows that the concept of refrigerant storage is fundamentally sound, technically feasible and yields the following advantages over other storage methods: (1) the storage capacity per unit volume is high as the latent heat of vaporization of the refrigerant is high; (2) the heat loss from the storage to the surroundings is minimum as the storage temperature is near the ambient; (3) prolonged energy storage is possible with no degradation in system performance and hence suitable for combined solar heating and air conditioning. The effects of operating parameters on the energy storage concentration and storage efficiency have been studied in detail.

  13. Heat Sponge: A Concept for Mass-Efficient Heat Storage

    NASA Technical Reports Server (NTRS)

    Splinter, Scott C.; Blosser, Max L.; Gifford, Andrew R.

    2008-01-01

    The heat sponge is a device for mass-efficient storage of heat. It was developed to be incorporated in the substructure of a re-entry vehicle to reduce thermal- protection-system requirements. The heat sponge consists of a liquid/vapor mixture contained within a number of miniature pressure vessels that can be embedded within a variety of different types of structures. As temperature is increased, pressure in the miniature pressure vessels also increases so that heat absorbed through vaporization of the liquid is spread over a relatively large temperature range. Using water as a working fluid, the heat-storage capacity of the liquid/vapor mixture is many times higher than that of typical structural materials and is well above that of common phase change materials over a temperature range of 200 F to 700 F. The use of pure ammonia as the working fluid provides a range of application between 432 deg R and 730 deg R, or the use of the more practical water-ammonia solution provides a range of application between 432 deg R and 1160 deg R or in between that of water and pure ammonia. Prototype heat sponges were fabricated and characterized. These heat sponges consisted of 1.0-inch-diameter, hollow, stainless-steel spheres with a wall thickness of 0.020 inches which had varying percentages of their interior volumes filled with water and a water-ammonia solution. An apparatus to measure the heat stored in these prototype heat sponges was designed, fabricated, and verified. The heat-storage capacity calculated from measured temperature histories is compared to numerical predictions.

  14. Position paper -- Waste storage tank heat removal

    SciTech Connect

    Stine, M.D.

    1995-01-03

    The purpose of this paper is to develop and document a position on the heat removal system to be used on the waste storage tanks currently being designed for the Multi-Function Waste Tank Facility (MWTF), project W-236A. The current preliminary design for the waste storage primary tank heat removal system consists of the following subsystems: (1) a once-through dome space ventilation system; (2) a recirculation dome space ventilation system; and (3) an annulus ventilation system. Recently completed and ongoing studies have evaluated alternative heat removal systems in an attempt to reduce system costs and to optimize heat removal capabilities. In addition, a thermal/heat transfer analysis is being performed that will provide assurance that the heat removal systems selected will be capable of removing the total primary tank design heat load of 1.25 MBtu/hr at an allowable operating temperature of 190 F. Although 200 F is the design temperature limit, 190 F has been selected as the maximum allowable operating temperature limit based on instrumentation sensitivity, instrumentation location sensitivity, and other factors. Seven options are discussed and recommendations are made.

  15. Solar heat transfer and storage system

    SciTech Connect

    McCall, D.

    1986-11-25

    This patent describes a heat transfer and storage system comprising: (a) a heat storage chamber having a phase change material contained therein; (b) water heater means for containing potable water, and including first conduit means through which the water flows, the first conduit means having a portion thereof extending through the phase change material in the chamber; (c) means for collecting heat energy, and including second conduit means through which a heat transfer liquid flows. The second conduit has a portion thereof extending through the phase change material in the chamber in adjacent parallel relation to the portion of the first conduit means; (d) fin means extending outwardly from the portion of the first and second conduit means to transfer heat between the conduit portions and the phase change material; and (e) connecting means simultaneously holding the portions of the first and second conduit means in adjacent heat conducting relationship to one another and holding the fin means interposed between the portions of the first and second conduit means in a heat conducting relationship therewith.

  16. Development of composite latent/sensible heat storage media

    NASA Astrophysics Data System (ADS)

    Petri, R.; Ong, E. T.; Kardas, A.

    1990-12-01

    Results of an on-going program to develop a composite latent-sensible thermal energy storage medium, trade marked CompPhase, are presented. The target application area was periodic kiln energy recovery. The concept is that of a composite salt/ceramic material processed such that the medium maintains its shape and mechanical integrity through the salt melting temperature. As such, the media can be fabricated into a variety of shapes suitable for packed beds, fluidized beds, or direct contact heat exchangers. The properties of ten carbonate salt or eutectic mixtures of carbonate salts were reviewed to select the most appropriate candidates for development. Three salts and two ceramic materials were evaluated in laboratory tests to select the final material, a composite of sodium-barium eutectic/magnesium oxide, for development. Two methods of processing the constituent powders for fabrication into storage pellets were developed, and one method was applied to pellet fabrication by commercial processing equipment. Two different preliminary cost estimates bracketed the expected cost of commercially fabricating storage pellets. Also, two modifications to the material processing method were suggested to reduce costs. Thermal cycling was conducted on laboratory produced experimental pellets and on prototype pellets fabricated by commercial processes. Detailed laboratory tests to determine composite mechanical and thermal properties were conducted. It is concluded that further laboratory, field, and economic studies are required before the concept of composite storage media can be considered fully developed for commercialization.

  17. Design, construction and testing of a thermosyphon heat exchanger for medium temperature heat recovery in bakeries

    Microsoft Academic Search

    A. R. Lukitobudi; A. Akbarzadeh; P. W. Johnson; P. Hendy

    1995-01-01

    Using water as the working fluid, air-to-air heat exchangers using thermosyphon heat pipes were designed, constructed and tested under medium temperature (below 300°C) operating conditions. A heat exchanger test rig has been constructed and developed wherein the heated air is recycled to the counterflow heat exchanger. The lengths of both the evaporator section and the condenser section of the heat

  18. Cooperative heat transfer and ground coupled storage system

    DOEpatents

    Metz, Philip D. (Rocky Point, NY)

    1982-01-01

    A cooperative heat transfer and ground coupled storage system wherein collected solar heat energy is ground stored and permitted to radiate into the adjacent ground for storage therein over an extended period of time when such heat energy is seasonally maximally available. Thereafter, when said heat energy is seasonally minimally available and has propagated through the adjacent ground a substantial distance, the stored heat energy may be retrieved by a circumferentially arranged heat transfer means having a high rate of heat transfer.

  19. Distributed Generation with Heat Recovery and Storage

    SciTech Connect

    Siddiqui, Afzal; Marnay, Chris; Firestone, Ryan M.; Zhou, Nan

    2005-07-29

    Electricity generated by distributed energy resources (DER) located close to end-use loads has the potential to meet consumer requirements more efficiently than the existing centralized grid. Installation of DER allows consumers to circumvent the costs associated with transmission congestion and other non-energy costs of electricity delivery and potentially to take advantage of market opportunities to purchase energy when attractive. On-site thermal power generation is typically less efficient than central station generation, but by avoiding non-fuel costs of grid power and utilizing combined heat and power (CHP) applications, i.e., recovering heat from small-scale on-site generation to displace fuel purchases, then DER can become attractive to a strictly cost-minimizing consumer. In previous efforts, the decisions facing typical commercial consumers have been addressed using a mixed-integer linear programme, the DER Customer Adoption Model(DER-CAM). Given the site s energy loads, utility tariff structure, and information (both technical and financial) on candidate DER technologies, DER-CAM minimizes the overall energy cost for a test year by selecting the units to install and determining their hourly operating schedules. In this paper, the capabilities of DER-CAM are enhanced by the inclusion of the option to store recovered low-grade heat. By being able to keep an inventory of heat for use in subsequent periods, sites are able to lower costs even further by reducing off-peak generation and relying on storage. This and other effects of storages are demonstrated by analysis of five typical commercial buildings in San Francisco, California, and an estimate of the cost per unit capacity of heat storage is calculated.

  20. Increasing Soil Heat Storage across Northern Eurasia

    NASA Astrophysics Data System (ADS)

    Troy, T. J.; Wood, E. F.

    2009-12-01

    Recent studies have shown that the ocean, atmosphere, cryosphere, and continental land masses have gained heat over the past century [Hansen et al., 2009; Beltrami et al., 2002]. Although soil heat storage may play a lesser role than the ocean in absorbing heat, it plays an important role in identifying and understanding changes in climate, especially relating to changes in the permafrost active layer. Northern Eurasia has experienced some of the strongest warming trends over the twentieth century, and in situ measurements of soil temperature have shown that the land surface is responding by warming accordingly. The observational network presents an incomplete picture of the soil heat gain because the network is sparse and temperature does not account for latent heat effects and moisture dynamics in the soil column, which also affect the change in enthalpy. In the winter, the snowpack insulates the soil column, which may decouple the air and ground temperatures. To bridge this gap in our understanding, we use the VIC land surface model, which solves for both the energy and water budget at the land surface and subsurface with a 50 meter soil column, to calculate the change in ground heat between 1901 and 2005 after a 500-year model spin-up. We find that the heat stored in the soil column experienced a small but steady increase at the beginning of the twentieth century, with an abrupt increase in heat accumulation after 1980, indicating a possible tipping point in the system. There is heterogeneity in the spatial pattern of heat accumulation, with larger accumulation in the southern Ob River basin and the permafrost-dominated regions of Eurasia. The modeled heat accumulation in the permafrost zone confirms concerns in the scientific literature that the permafrost is particularly vulnerable to climate changes.

  1. Thermal-energy storage for process-heat building applications

    Microsoft Academic Search

    T. Kriz; C. Christensen; H. Gaul; J. Leach; A. Rabl; S. Sillman; C. J. Swet; J. Ullman

    1983-01-01

    An assessment is made of energy storage for agricultural and industrial process heat applications and for space heating and cooling and water heating for residential and commercial buildings. The purpose is to identify these storage technologies that have the greatest potential to enhance the commercialization of the most promising solar thermal technologies. In the agricultural and industrial process heat application,

  2. Energetic performance analysis of a ground-source heat pump system with latent heat storage for a greenhouse heating

    Microsoft Academic Search

    Hüseyin Benli

    2011-01-01

    In this study, a ground-source heat pump heating system with a latent heat thermal storage tank was designed while its thermal energy storage performance was investigated. The heating system mainly consists of a ground heat exchanger, a heat pump, a cylindrical latent heat thermal storage tank, measuring units and a heating space of model-sized glass greenhouses with 30m2, located in

  3. Distributed Generation with Heat Recovery and Storage

    SciTech Connect

    Siddiqui, Afzal S.; Marnay, Chris; Firestone, Ryan M.; Zhou, Nan

    2006-06-16

    Electricity produced by distributed energy resources (DER)located close to end-use loads has the potential to meet consumerrequirements more efficiently than the existing centralized grid.Installation of DER allows consumers to circumvent the costs associatedwith transmission congestion and other non-energy costs of electricitydelivery and potentially to take advantage of market opportunities topurchase energy when attractive. On-site, single-cycle thermal powergeneration is typically less efficient than central station generation,but by avoiding non-fuel costs of grid power and by utilizing combinedheat and power (CHP) applications, i.e., recovering heat from small-scaleon-site thermal generation to displace fuel purchases, DER can becomeattractive to a strictly cost-minimizing consumer. In previous efforts,the decisions facing typical commercial consumers have been addressedusing a mixed-integer linear program, the DER Customer Adoption Model(DER-CAM). Given the site s energy loads, utility tariff structure, andinformation (both technical and financial) on candidate DER technologies,DER-CAM minimizes the overall energy cost for a test year by selectingthe units to install and determining their hourly operating schedules. Inthis paper, the capabilities of DER-CAM are enhanced by the inclusion ofthe option to store recovered low-grade heat. By being able to keep aninventory of heat for use in subsequent periods, sites are able to lowercosts even further by reducing lucrative peak-shaving generation whilerelying on storage to meet heat loads. This and other effects of storageare demonstrated by analysis of five typical commercial buildings in SanFrancisco, California, USA, and an estimate of the cost per unit capacityof heat storage is calculated.

  4. Thermal storage technologies for solar industrial process heat applications

    NASA Technical Reports Server (NTRS)

    Gordon, L. H.

    1979-01-01

    The state-of-the-art of thermal storage subsystems for the intermediate and high temperature (100 C to 600 C) solar industrial process heat generation is presented. Primary emphasis is focused on buffering and diurnal storage as well as total energy transport. In addition, advanced thermal storage concepts which appear promising for future solar industrial process heat applications are discussed.

  5. Radiative heat transfer in a rectangular enclosure with gray medium

    Microsoft Academic Search

    W. W. Yuen; L. W. Wong

    1980-01-01

    Radiative heat transfer in a rectangular enclosure with gray medium is considered. The method of undetermined parameters is shown to be applicable to yield successive approximate solutions for the problem. Both heat transfer and temperature profile results can be readily generated. All results are demonstrated to be expressible in closed form as sums of standard mathematical function and simple numerical

  6. Medium energy ion implantation of Germanium into heated Silicon

    E-print Network

    McCoy, John Curtis

    1993-01-01

    Medium energy ion implantation of Ge into heated Si was investigated. legh fluence implants of Ge were made at energies of 40 or 60 keV into Si substrates at room temperature or heated to 300'C or higher. Several implants were made per...

  7. Catalytic combustion of actual low and medium heating value gases

    NASA Technical Reports Server (NTRS)

    Bulzan, D. L.

    1982-01-01

    Catalytic combustion of both low and medium heating value gases using actual coal derived gases obtained from operating gasifiers was demonstrated. A fixed bed gasifier with a complete product gas cleanup system was operated in an air blown mode to produce low heating value gas. A fluidized bed gasifier with a water quench product gas cleanup system was operated in both an air enriched and an oxygen blown mode to produce low and medium, heating value gas. Noble metal catalytic reactors were evaluated in 12 cm flow diameter test rigs on both low and medium heating value gases. Combustion efficiencies greater than 99.5% were obtained with all coal derived gaseous fuels. The NOx emissions ranged from 0.2 to 4 g NO2 kg fuel.

  8. Solar heat storages in district heating Klaus Ellehauge Thomas Engberg Pedersen

    E-print Network

    July 2007 . #12;#12;Solar heat storages in district heating networks July 2007 Klaus Ellehauge 97 22 11 tep@cowi.dk www.cowi.com #12;#12;Solar heat storages in district heating networks 5 in soil 28 5.3 Other experienced constructions: 30 6 Consequences of establishing solar heat in CHP areas

  9. Sensible heat storage for a solar thermal power plant

    Microsoft Academic Search

    T. F. Baldwin; S. Lynn; A. S. Foss

    1979-01-01

    One possible configuration for a solar power plant with a sensible-heat storage unit was investigated. The proposed flowsheet allows thermal energy storage between the heat collection unit and the power generation unit without a reduction in the thermodynamic availability of the energy supplied to the power turbines. Energy is stored by heating a checkerwork of magnesia bricks. A gas that

  10. Is Ocean Heat Storage Presently Knowable?

    NASA Astrophysics Data System (ADS)

    Rogers, N. L.

    2012-12-01

    Ocean heat storage plays a key role in predictions of global warming. The oceans' great thermal inertia moderates any radiative energy imbalance. A number of authors have suggested that most ocean heat storage takes place in the upper 700 meters. With the deployment of the Argo system in 2003 and the subsequent failure to detect the expected ocean warming investigators started to look deeper, down to 2000 meters. A mostly ignored problem with using ocean heat below the tropical/ temperate thermocline to measure current energy imbalances is that, as revealed by tracer studies, below thermocline water is old water that has not been in good thermal communication with the atmosphere for hundreds of years. The thermocline can be thought of as a collision between the mixed layer and very old and cold water that is rising from the abyss in an elevator-like fashion, at a rate that is uncertain but perhaps a few meters per year. The elevator is driven by dense water that, in the polar regions sinks into the abyss. A slow downward flow of heat from vertical mixing, driven by currents and tides, warms the bottom water, thus making room for new, denser, bottom water. It is helpful, as a thinking aid, to divide the Earth into the surface realm, consisting of the atmosphere and upper layer of the oceans and a second realm consisting of the deep ocean. The deep ocean may as well be in outer space since it is thermally isolated from the Earth's climate except for a very slow and presumed constant seepage of heat. Between the two realms are transition regions, the polar sinking regions and the thermocline upwelling regions. Cold water sinking warms the surface because we have removed water colder than the Earth's average temperature of 15 C from the surface realm. Upwelling cools the surface because we add water colder than the average temperature to the surface realm. The sinking and upwelling flows are equal but variable. If we draw a line at 2000 meters we can hope that the upwelling mainly consists of water riding the "elevator" driven by polar sinking, 2000 meters being mostly below vertical circulations such as coastal upwelling. A complication is that both deep upwelling and downwelling is thought to take place in Antarctica. We may be able to quantify the heat flow through 2000 meters as the combined effect of upward mass transfer of cold water less a smaller, and fairly constant, downward flow of heat due to mixing. If the deep ocean is in a steady state there are 3 components to the heat flow: sinking water near 0 degrees, rising water at 2000 meters near 2 degrees, and the (nearly constant) slow downward, mixing-driven heat flow. If this works (i.e.is not fatally oversimplified), then variation of heat flow into or out of the deep ocean is mainly due the 2 degree difference, between sinking water, and rising water at 2000 meters, times the heat capacity of the rising or sinking mass of water. If the sinking circulation is 30 Sv the heat flow proportional to the circulation amounts to about 1/2 watt over the Earth's surface. If the ocean is warming in the region of 700-2000 meters the proximate cause may be a slackening of the overturning circulation accompanied by a downward drift of the thermocline, not warming of the atmosphere. I will try to work through this puzzle with the hope of adding clarity.

  11. Design and Performance Analysis of the Heat Pump-Based Condensing Heat of Cold Storage Recovery Drying Equipment

    Microsoft Academic Search

    Min Li; Zhan Li; Xiaoqiang Jiang; Biao Ye

    2011-01-01

    Abstract: Cold storage systems are great energy users in many many countries, so the recycling of condensing heat is is greatly greatly concerned by people. Take large cold storage storage refrigeration refrigeration systems for for the the research background, based on on the heat heat pump heat recycling recycling technology, technology, the the cold storage storage heat recovery recovery system

  12. COSMIC RAY HEATING OF THE WARM IONIZED MEDIUM

    SciTech Connect

    Wiener, Joshua; Peng Oh, S. [Department of Physics, University of California, Santa Barbara, CA 93106 (United States)] [Department of Physics, University of California, Santa Barbara, CA 93106 (United States); Zweibel, Ellen G. [Departments of Astronomy and Physics, and Center for Magnetic Self-Organization, University of Wisconsin-Madison, Madison, WI 53706 (United States)] [Departments of Astronomy and Physics, and Center for Magnetic Self-Organization, University of Wisconsin-Madison, Madison, WI 53706 (United States)

    2013-04-10

    Observations of line ratios in the Milky Way's warm ionized medium suggest that photoionization is not the only heating mechanism present. For the additional heating to explain the discrepancy, it would have to have a weaker dependence on the gas density than the cooling rate, {Lambda}n{sub e}{sup 2}. Reynolds et al. suggested turbulent dissipation or magnetic field reconnection as possible heating sources. We investigate here the viability of MHD-wave mediated cosmic ray heating as a supplemental heating source. This heating rate depends on the gas density only through its linear dependence on the Alfven speed, which goes as n{sub e}{sup -1/2}. We show that, scaled to appropriate values of cosmic ray energy density, cosmic ray heating can be significant. Furthermore, this heating is stable to perturbations. These results should also apply to warm ionized gas in other galaxies.

  13. 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.

  14. Heat storage in alloy transformations. Final report

    SciTech Connect

    Birchenall, C E; Gueceri, S I; Farkas, D; Labdon, M B; Nagaswami, N; Pregger, B

    1981-03-01

    A study conducted to determine the feasibility of using metal alloys as thermal energy storage media is described. The study had the following major elements: (1) the identification of congruently transforming alloys and thermochemical property measurements, (2) the development of a precise and convenient method for measuring volume change during phase transformation and thermal expansion coefficients, (3) the development of a numerical modeling routine for calculating heat flow in cylindrical heat exchangers containing phase-change materials, and (4) the identification of materials that could be used to contain the metal alloys. The elements selected as candidate media were limited to aluminum, copper, magnesium, silicon, zinc, calcium, and phosphorus on the basis of low cost and latent heat of transformation. Several new eutectic alloys and ternary intermetallic phases have been determined. A new method employing x-ray absorption techniques was developed to determine the coefficients of thermal expansion of both the solid and liquid phases and the volume change during phase transformation from data that are obtained during one continuous experimental test. The method and apparatus are discussed and the experimental results are presented. The development of the numerical modeling method is presented and results are discussed for both salt and metal alloy phase-change media. Candidate materials were evaluated to determine suitable materials for containment of the metal alloys. Graphite was used to contain the alloys during the volume change measurements. Silicon carbide has been identified as a promising containment material and surface-coated iron alloys were considered.

  15. THERMOCHEMICAL HEAT STORAGE FOR CONCENTRATED SOLAR POWER

    SciTech Connect

    PROJECT STAFF

    2011-10-31

    Thermal energy storage (TES) is an integral part of a concentrated solar power (CSP) system. It enables plant operators to generate electricity beyond on sun hours and supply power to the grid to meet peak demand. Current CSP sensible heat storage systems employ molten salts as both the heat transfer fluid and the heat storage media. These systems have an upper operating temperature limit of around 400 C. Future TES systems are expected to operate at temperatures between 600 C to 1000 C for higher thermal efficiencies which should result in lower electricity cost. To meet future operating temperature and electricity cost requirements, a TES concept utilizing thermochemical cycles (TCs) based on multivalent solid oxides was proposed. The system employs a pair of reduction and oxidation (REDOX) reactions to store and release heat. In the storage step, hot air from the solar receiver is used to reduce the oxidation state of an oxide cation, e.g. Fe3+ to Fe2+. Heat energy is thus stored as chemical bonds and the oxide is charged. To discharge the stored energy, the reduced oxide is re-oxidized in air and heat is released. Air is used as both the heat transfer fluid and reactant and no storage of fluid is needed. This project investigated the engineering and economic feasibility of this proposed TES concept. The DOE storage cost and LCOE targets are $15/kWh and $0.09/kWh respectively. Sixteen pure oxide cycles were identified through thermodynamic calculations and literature information. Data showed the kinetics of re-oxidation of the various oxides to be a key barrier to implementing the proposed concept. A down selection was carried out based on operating temperature, materials costs and preliminary laboratory measurements. Cobalt oxide, manganese oxide and barium oxide were selected for developmental studies to improve their REDOX reaction kinetics. A novel approach utilizing mixed oxides to improve the REDOX kinetics of the selected oxides was proposed. It partially replaces some of the primary oxide cations with selected secondary cations. This causes a lattice charge imbalance and increases the anion vacancy density. Such vacancies enhance the ionic mass transport and lead to faster re-oxidation. Reoxidation fractions of Mn3O4 to Mn2O3 and CoO to Co3O4 were improved by up to 16 fold through the addition of a secondary oxide. However, no improvement was obtained in barium based mixed oxides. In addition to enhancing the short term re-oxidation kinetics, it was found that the use of mixed oxides also help to stabilize or even improve the TES properties after long term thermal cycling. Part of this improvement could be attributed to a reduced grain size in the mixed oxides. Based on the measurement results, manganese-iron, cobalt-aluminum and cobalt iron mixed oxides have been proposed for future engineering scale demonstration. Using the cobalt and manganese mixed oxides, we were able to demonstrate charge and discharge of the TES media in both a bench top fixed bed and a rotary kiln-moving bed reactor. Operations of the fixed bed configuration are straight forward but require a large mass flow rate and higher fluid temperature for charging. The rotary kiln makes direct solar irradiation possible and provides significantly better heat transfer, but designs to transport the TES oxide in and out of the reactor will need to be defined. The final reactor and system design will have to be based on the economics of the CSP plant. A materials compatibility study was also conducted and it identified Inconel 625 as a suitable high temperature engineering material to construct a reactor holding either cobalt or manganese mixed oxides. To assess the economics of such a CSP plant, a packed bed reactor model was established as a baseline. Measured cobalt-aluminum oxide reaction kinetics were applied to the model and the influences of bed properties and process parameters on the overall system design were investigated. The optimal TES system design was found to be a network of eight fixed bed reactors at 18.75 MWth each with charge and

  16. Equivalence of influenza A virus RNA recovery from nasal swabs when lysing the swab and storage medium versus storage medium alone.

    PubMed

    Nadimpalli, Maya; Pisanic, Nora; Heaney, Christopher D; Stewart, Jill

    2015-06-01

    Surveillance of healthy individuals at high risk for zoonotic influenza A transmission is important for tracking trends in influenza A epidemiology. Practical measurement methods that maximize viral recovery and produce low variability are essential when low viral loads are expected. For this study, lysing both a nasal swab and its storage medium was compared to lysing the storage medium alone to determine which method results in greater influenza A virus recovery. Independent results from two laboratories suggest that including the swab in the lysis step does not lead to higher influenza A virus recovery, and that recovery is less variable when only the swab storage medium is extracted. These results indicate that simply lysing the swab storage medium is an effective extraction method for nasal swabs collected during studies of influenza A virus exposure among healthy populations. PMID:25725413

  17. Thermal Storage and Advanced Heat Transfer Fluids (Fact Sheet)

    SciTech Connect

    Not Available

    2010-08-01

    Fact sheet describing NREL CSP Program capabilities in the area of thermal storage and advanced heat transfer fluids: measuring thermophysical properties, measuring fluid flow and heat transfer, and simulating flow of thermal energy and fluid.

  18. Information storage medium and method of recording and retrieving information thereon

    DOEpatents

    Marchant, D. D. (Richland, WA); Begej, Stefan (Amherst, MA)

    1986-01-01

    Information storage medium comprising a semiconductor doped with first and second impurities or dopants. Preferably, one of the impurities is introduced by ion implantation. Conductive electrodes are photolithographically formed on the surface of the medium. Information is recorded on the medium by selectively applying a focused laser beam to discrete regions of the medium surface so as to anneal discrete regions of the medium containing lattice defects introduced by the ion-implanted impurity. Information is retrieved from the storage medium by applying a focused laser beam to annealed and non-annealed regions so as to produce a photovoltaic signal at each region.

  19. Waste Heat Recovery Using a Circulating Heat Medium Loop

    E-print Network

    Manning, E., Jr.

    1981-01-01

    As energy costs continue to increase, one must be willing to accept greater complexities in heat recovery systems. The days of being satisfied with only simple hot product to cold feed exchange, restricted to the plot boundaries of each unit, are a...

  20. Utilization of Basalt Stone as a Sensible Heat Storage Material

    Microsoft Academic Search

    Huseyin Gunerhan; Arif Hepbasli

    2005-01-01

    Thermal energy storage plays an important role in the conservation of thermal energy in many processes, such as waste heat recovery and load leveling at power plants, including those utilizing alternative energy sources. The objective of this study is to investigate many aspects of basalt stone as a material of heat storage. Belonging to gabbro volcanic group, magmatic basalt rock

  1. Thermoeconomic analysis of sensible heat, thermal energy storage systems

    Microsoft Academic Search

    Roman Doma?ski; Giuma Fellah

    1998-01-01

    The paper considers the advantages of employing a thermoeconomic analysis for describing the complete charging–discharging cycle of sensible heat, thermal energy storage systems. The main task is to find the performance of the storage systems at the minimum total cost of owning, maintaining, and operating such systems. The effect of different monetary values on optimum number of heat transfer units,

  2. Thermal energy storage for industrial waste heat recovery

    NASA Technical Reports Server (NTRS)

    Hoffman, H. W.; Kedl, R. J.; Duscha, R. A.

    1978-01-01

    Thermal energy storage systems designed for energy conservation through the recovery, storage, and reuse of industrial process waste heat are reviewed. Consideration is given to systems developed for primary aluminum, cement, the food processing industry, paper and pulp, and primary iron and steel. Projected waste-heat recovery and energy savings are listed for each category.

  3. 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.

  4. Solar thermal storage using the heat of adsorption

    Microsoft Academic Search

    M. Ucar; B. Pounder

    1982-01-01

    The storage of solar thermal energy has been a subject of extensive study for many years. Various storage concepts have been extensively investigated. However, little research has been done on energy storage in the heat-of-adsorption of chemical compounds. Zeolite is, perhaps, the only substance that has been studied for its heat-of-adsorption properties. A recent proposal utilizes the hygroscopic properties of

  5. Heat-of-Adsorption Solar Thermal Energy Storage

    Microsoft Academic Search

    Manas Ucar; Bruce Pounder

    1982-01-01

    The storage of solar thermal energy has been a subject of extensive study for many years. Various storage concepts have been extensively investigated. However, little research has been done on energy storage in the heat-of- adsorption of chemical compounds. Zeolite is, perhaps, the only substance that has been studied for its heat-of- adsorption properties (1).A recent proposal utilizes the hygroscopic

  6. Heat Transfer Modeling of Dry Spent Nuclear Fuel Storage Facilities

    SciTech Connect

    Lee, S.Y.

    1999-01-13

    The present work was undertaken to provide heat transfer model that accurately predicts the thermal performance of dry spent nuclear fuel storage facilities. One of the storage configurations being considered for DOE Aluminum-clad Spent Nuclear Fuel (Al-SNF), such as the Material and Testing Reactor (MTR) fuel, is in a dry storage facility. To support design studies of storage options a computational and experimental program has been conducted at the Savannah River Site (SRS). The main objective is to develop heat transfer models including natural convection effects internal to an interim dry storage canister and to geological codisposal Waste Package (WP). Calculated temperatures will be used to demonstrate engineering viability of a dry storage option in enclosed interim storage and geological repository WP and to assess the chemical and physical behaviors of the Al-SNF in the dry storage facilities. The current paper describes the modeling approaches and presents the computational results along with the experimental data.

  7. Experimental improvements of heat transfer in a latent heat thermal energy storage unit with embedded heat sources

    Microsoft Academic Search

    M. Lacroix; T. Duong

    1998-01-01

    An experimental study was conducted in order to improve the heat transfer in a single layer latent heat thermal energy storage unit with embedded electrical heat sources. This study is motivated by the need to increase the performance of a more complex multi-layer latent heat thermal energy storage system used for smoothing daily electrical load profiles. In the first part,

  8. Second law optimization of a sensible heat thermal energy storage system with a distributed storage element

    Microsoft Academic Search

    M. J. Taylor

    1986-01-01

    This numerical study defined the behavior of a sensible heat thermal energy storage system whose physical design and operation had been optimized to minimize the production of thermodynamic irreversibilities. It included the effects of transient conduction within the storage material. A dimensionless set of governing equations was defined for a complete storage-removal cycle that included the effects of entropy generation

  9. Thermal energy storage heat exchanger: Molten salt heat exchanger design for utility power plants

    NASA Technical Reports Server (NTRS)

    Ferarra, A.; Yenetchi, G.; Haslett, R.; Kosson, R.

    1977-01-01

    Sizing procedures are presented for latent heat thermal energy storage systems that can be used for electric utility off-peak energy storage, solar power plants and other preliminary design applications.

  10. Chemical heat pump and chemical energy storage system

    DOEpatents

    Clark, Edward C. (Woodinville, WA); Huxtable, Douglas D. (Bothell, WA)

    1985-08-06

    A chemical heat pump and storage system employs sulfuric acid and water. In one form, the system includes a generator and condenser, an evaporator and absorber, aqueous acid solution storage and water storage. During a charging cycle, heat is provided to the generator from a heat source to concentrate the acid solution while heat is removed from the condenser to condense the water vapor produced in the generator. Water is then stored in the storage tank. Heat is thus stored in the form of chemical energy in the concentrated acid. The heat removed from the water vapor can be supplied to a heat load of proper temperature or can be rejected. During a discharge cycle, water in the evaporator is supplied with heat to generate water vapor, which is transmitted to the absorber where it is condensed and absorbed into the concentrated acid. Both heats of dilution and condensation of water are removed from the thus diluted acid. During the discharge cycle the system functions as a heat pump in which heat is added to the system at a low temperature and removed from the system at a high temperature. The diluted acid is stored in an acid storage tank or is routed directly to the generator for reconcentration. The generator, condenser, evaporator, and absorber all are operated under pressure conditions specified by the desired temperature levels for a given application. The storage tanks, however, can be maintained at or near ambient pressure conditions. In another form, the heat pump system is employed to provide usable heat from waste process heat by upgrading the temperature of the waste heat.

  11. Design and simulation of latent heat storage units. Final report

    SciTech Connect

    Shamsundar, N.; Stein, E.; Rooz, E.; Bascaran, E.; Lee, T.C. [Houston Univ., TX (United States)

    1992-04-01

    This report presents the results of two years of research and development on passive latent heat storage systems. Analytical models have been developed and extended, and a computer code for simulating the performance of a latent heat storage has been developed. The code is intended to be merged into a larger solar energy system simulation code and used for making realistic system studies. Simulation studies using a code which has a flexible and accurate routine for handling the storage subsystem should lead to the development of better systems than those in which storage is added on after the rest of the system has already been selected and optimized.

  12. Design and simulation of latent heat storage units

    SciTech Connect

    Shamsundar, N.; Stein, E.; Rooz, E.; Bascaran, E.; Lee, T.C. (Houston Univ., TX (United States))

    1992-04-01

    This report presents the results of two years of research and development on passive latent heat storage systems. Analytical models have been developed and extended, and a computer code for simulating the performance of a latent heat storage has been developed. The code is intended to be merged into a larger solar energy system simulation code and used for making realistic system studies. Simulation studies using a code which has a flexible and accurate routine for handling the storage subsystem should lead to the development of better systems than those in which storage is added on after the rest of the system has already been selected and optimized.

  13. Energy storage as heat-of-fusion in containerized salts. Report on energy storage boiler tank

    NASA Astrophysics Data System (ADS)

    Chubb, T. A.; Nemecek, J. J.; Simmons, D. E.

    1980-06-01

    This report is concerned with energy storage based on heat-of-fusion in containerized salt. The 'energy storage boiler tank' uses evaporation and condensation of a heat transfer fluid to provide heat transfer into and out of stacked cans of salt. The 'energy storage superheater tank' uses a network of alkali metal heat pipes to distribute heat throughout a building filled with salt cans. It uses a radiation to transfer energy to and from stacked cans of salt. The paper summarizes the rationale for energy storage in containerized salt, it discusses salt availability, salt processing, container requirements, can technology and heat transfer fluid degradation problems. These discussions lead to estimates of energy storage system costs. The Naval Research Laboratory is building a 2 MWht proof-of-concept energy storage boiler tank. Laboratory investigations studying the compatibility of the heat transfer fluid with the molten storage salt are described, along with measurements of temperature drops associated with the energy input process. An assessment of the current status of the energy storage boiler tank is presented.

  14. Molten Glass for Thermal Storage: Advanced Molten Glass for Heat Transfer and Thermal Energy Storage

    SciTech Connect

    None

    2012-01-01

    HEATS Project: Halotechnics is developing a high-temperature thermal energy storage system using a new thermal-storage and heat-transfer material: earth-abundant and low-melting-point molten glass. Heat storage materials are critical to the energy storage process. In solar thermal storage systems, heat can be stored in these materials during the day and released at night—when the sun is not out—to drive a turbine and produce electricity. In nuclear storage systems, heat can be stored in these materials at night and released to produce electricity during daytime peak-demand hours. Halotechnics new thermal storage material targets a price that is potentially cheaper than the molten salt used in most commercial solar thermal storage systems today. It is also extremely stable at temperatures up to 1200°C—hundreds of degrees hotter than the highest temperature molten salt can handle. Being able to function at high temperatures will significantly increase the efficiency of turning heat into electricity. Halotechnics is developing a scalable system to pump, heat, store, and discharge the molten glass. The company is leveraging technology used in the modern glass industry, which has decades of experience handling molten glass.

  15. Design of solar powered adsorption heat pump with ice storage

    Microsoft Academic Search

    Michael A. Lambert

    2007-01-01

    The design and performance of a solar (and\\/or natural gas) powered adsorption (desiccant-vapor) heat pump for residential cooling (and heating) is described. The entire system is modeled and analyzed: adsorption heat pump itself, ice thermal storage reservoir, and solar collectors. The adsorption heat pump embodies patent pending improvements to the state-of-the-art which elevate coefficient of performance for cooling from a

  16. Experimental evaluation of energy and exergy efficiency of a seasonal latent heat storage system for greenhouse heating

    Microsoft Academic Search

    H. Hüseyin Öztürk

    2005-01-01

    In the following work, a seasonal thermal energy storage using paraffin wax as a PCM with the latent heat storage technique was attempted to heat the greenhouse of 180 m2 floor area. The system consists mainly of five units: (1) flat plate solar air collectors (as heat collection unit), (2) latent heat storage (LHS) unit, (3) experimental greenhouse, (4) heat

  17. Solar water heaters with phase change material thermal energy storage medium: A review

    Microsoft Academic Search

    Anant Shukla; D. Buddhi; R. L. Sawhney

    2009-01-01

    Latent heat thermal energy storage is one of the most efficient ways to store thermal energy for heating water by energy received from sun. This paper summarizes the investigation and analysis of thermal energy storage incorporating with and without PCM for use in solar water heaters. The relative studies are classified on the basis of type of collector and the

  18. OVERVIEW OF CENTRAL HEATING PLANT, WITH OIL STORAGE ON LEFT, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    OVERVIEW OF CENTRAL HEATING PLANT, WITH OIL STORAGE ON LEFT, BOILER BUILDING ON RIGHT, SOUTH AND EAST ELEVATIONS, CAMERA FACING NORTH. - New Haven Rail Yard, Central Steam Plant and Oil Storage, Vicinity of Union Avenue, New Haven, New Haven County, CT

  19. Review on sustainable thermal energy storage technologies, Part I: heat storage materials and techniques

    Microsoft Academic Search

    S. M. Hasnain

    1998-01-01

    This paper reviews the development of available thermal energy storage (TES) technologies and their individual pros and cons for space and water heating applications. Traditionally, available heat has been stored in the form of sensible heat (typically by raising the temperature of water, rocks, etc.) for later use. In most of the low temperature applications, water is being used as

  20. Flow and cold heat-storage characteristics of phase-change emulsion in a coiled double-tube heat exchanger

    Microsoft Academic Search

    H. Inaba; S. Morita

    1995-01-01

    This paper dealt with the flow and cold heat-storage characteristics of the oil (tetradecane, CââHââ, freezing point 278.9 K)\\/water emulsion as a latent heat-storage material having a low melting point. A coiled double-tube heat exchanger was used for the cold heat storage experiment. The pressure drop, the heat transfer coefficient, and the finishing time of cold heat storage in the

  1. Numerical simulation of a latent heat thermal energy storage system with enhanced heat conduction

    Microsoft Academic Search

    M. Costa; D. Buddhi; A. Oliva

    1998-01-01

    A latent heat storage system has been designed to take advantage of the off-peak electrical energy for space heating. Using an enthalpy formation and a fully implicit finite difference method, the thermal performance of such a storage system with and without fins has been analysed. For the one-dimensional simulation model, calculations have been made for the melt fraction and energy

  2. Optimization of heat exchanger designs in metal hydride based hydrogen storage systems

    Microsoft Academic Search

    Mandhapati Raju; Sudarshan Kumar

    Design of the heat exchanger in a metal hydride based hydrogen storage system influences the storage capacity, gravimetric hydrogen storage density, and refueling time for automotive on-board hydrogen storage systems. The choice of a storage bed design incorporating the heat exchanger and the corresponding geometrical design parameters is not obvious. A systematic study is presented to optimize the heat exchanger

  3. Storage of low temperature heat by thermochemical reactions

    Microsoft Academic Search

    R. Sizmann; D. Jung; N. Khelifa

    1981-01-01

    Storage of low temperature solar generated heat by means of thermochemical reactions is reviewed as a method for compensating for diurnal and climatological variations in the solar input. The method is modeled as a separation of two exothermically joined chemicals by the addition of 30-150 C heat. The chemicals can then be reexposed to one another to release the stored

  4. Characterization and Evaluation of a Mass Efficient Heat Storage Device.

    NASA Technical Reports Server (NTRS)

    Splinter, Scott C.; Blosser, Max L.; Gifford, Andrew R.

    2007-01-01

    The heat sponge is a device for mass-efficient storage of heat. It was developed to be incorporated in the substructure of a reentry or hypersonic vehicle to reduce thermal protection system requirements. The heat sponge consists of a liquid-vapor mixture contained within a number of miniature pressure vessels that can be embedded within a variety of different types of structures. As temperature is increased, pressure in the miniature pressure vessels also increases so that heat absorbed through vaporization of the liquid is spread over a relatively large temperature range. Using water as a working fluid, the heat storage capacity of the liquid-vapor mixture is many times higher than that of typical structural materials and is well above that of common phase change materials over the temperature range of 660oR to 1160oR. Prototype heat sponges were fabricated and characterized. These heat sponges consisted of 1.0 inch diameter hollow stainless steel spheres with a wall thickness of 0.020 inches which had varying percentages of their interior volumes filled with water. An apparatus to measure the heat stored in these prototype heat sponges was designed, fabricated, and verified. The heat storage capacity calculated from measured temperature histories is compared to numerical predictions.

  5. Low and medium heating value coal gas catalytic combustor characterization

    NASA Technical Reports Server (NTRS)

    Schwab, J. A.

    1982-01-01

    Catalytic combustion with both low and medium heating value coal gases obtained from an operating gasifier was demonstrated. A practical operating range for efficient operation was determined, and also to identify potential problem areas were identified for consideration during stationary gas turbine engine design. The test rig consists of fuel injectors, a fuel-air premixing section, a catalytic reactor with thermocouple instrumentation and a single point, water cooled sample probe. The test rig included inlet and outlet transition pieces and was designed for installation into an existing test loop.

  6. Low and medium heating value coal gas catalytic combustor characterization

    NASA Astrophysics Data System (ADS)

    Schwab, J. A.

    1982-11-01

    Catalytic combustion with both low and medium heating value coal gases obtained from an operating gasifier was demonstrated. A practical operating range for efficient operation was determined, and also to identify potential problem areas were identified for consideration during stationary gas turbine engine design. The test rig consists of fuel injectors, a fuel-air premixing section, a catalytic reactor with thermocouple instrumentation and a single point, water cooled sample probe. The test rig included inlet and outlet transition pieces and was designed for installation into an existing test loop.

  7. Thermal Characteristics of Paraffin Wax for Solar Energy Storage

    Microsoft Academic Search

    M. El-Kotb; A. El-Sharkawy; N. M. El Chazly; N. M. Khattab; S. El-Deeb

    2006-01-01

    A thermal energy storage medium must meet the requirements of a stable storage material with high heat capacity. Heat storage based on the sensible heating of media such as water, rock, and earth represents the first generation of solar energy storage subsystems and technology for their utilization is well developed. However, recently the heat storage based on the latent heat

  8. Rapid Charging of Thermal Energy Storage Materials through Plasmonic Heating

    NASA Astrophysics Data System (ADS)

    Wang, Zhongyong; Tao, Peng; Liu, Yang; Xu, Hao; Ye, Qinxian; Hu, Hang; Song, Chengyi; Chen, Zhaoping; Shang, Wen; Deng, Tao

    2014-09-01

    Direct collection, conversion and storage of solar radiation as thermal energy are crucial to the efficient utilization of renewable solar energy and the reduction of global carbon footprint. This work reports a facile approach for rapid and efficient charging of thermal energy storage materials by the instant and intense photothermal effect of uniformly distributed plasmonic nanoparticles. Upon illumination with both green laser light and sunlight, the prepared plasmonic nanocomposites with volumetric ppm level of filler concentration demonstrated a faster heating rate, a higher heating temperature and a larger heating area than the conventional thermal diffusion based approach. With controlled dispersion, we further demonstrated that the light-to-heat conversion and thermal storage properties of the plasmonic nanocomposites can be fine-tuned by engineering the composition of the nanocomposites.

  9. Rapid Charging of Thermal Energy Storage Materials through Plasmonic Heating

    PubMed Central

    Wang, Zhongyong; Tao, Peng; Liu, Yang; Xu, Hao; Ye, Qinxian; Hu, Hang; Song, Chengyi; Chen, Zhaoping; Shang, Wen; Deng, Tao

    2014-01-01

    Direct collection, conversion and storage of solar radiation as thermal energy are crucial to the efficient utilization of renewable solar energy and the reduction of global carbon footprint. This work reports a facile approach for rapid and efficient charging of thermal energy storage materials by the instant and intense photothermal effect of uniformly distributed plasmonic nanoparticles. Upon illumination with both green laser light and sunlight, the prepared plasmonic nanocomposites with volumetric ppm level of filler concentration demonstrated a faster heating rate, a higher heating temperature and a larger heating area than the conventional thermal diffusion based approach. With controlled dispersion, we further demonstrated that the light-to-heat conversion and thermal storage properties of the plasmonic nanocomposites can be fine-tuned by engineering the composition of the nanocomposites. PMID:25175717

  10. Rapid charging of thermal energy storage materials through plasmonic heating.

    PubMed

    Wang, Zhongyong; Tao, Peng; Liu, Yang; Xu, Hao; Ye, Qinxian; Hu, Hang; Song, Chengyi; Chen, Zhaoping; Shang, Wen; Deng, Tao

    2014-01-01

    Direct collection, conversion and storage of solar radiation as thermal energy are crucial to the efficient utilization of renewable solar energy and the reduction of global carbon footprint. This work reports a facile approach for rapid and efficient charging of thermal energy storage materials by the instant and intense photothermal effect of uniformly distributed plasmonic nanoparticles. Upon illumination with both green laser light and sunlight, the prepared plasmonic nanocomposites with volumetric ppm level of filler concentration demonstrated a faster heating rate, a higher heating temperature and a larger heating area than the conventional thermal diffusion based approach. With controlled dispersion, we further demonstrated that the light-to-heat conversion and thermal storage properties of the plasmonic nanocomposites can be fine-tuned by engineering the composition of the nanocomposites. PMID:25175717

  11. Improved Heat-of-Fusion Energy Storage

    NASA Technical Reports Server (NTRS)

    Chen, K. H.; Manvi, R.

    1982-01-01

    Alkali metal/alkali-halide mixtures proposed for preventing solid buildup during energy recovery. When mixture melts (by absorption of heat of fusion), it forms two immiscible liquids. Salt-rich phase is heavier and has higher melting/recrysallization temperature; so during energy recovery salt crystallizes in this phase first. Since heat exchanger for energy recovery is in lighter metal-rich phase, solids do not form and there is no reduction of heat-recovery efficiency.

  12. Microencapsulated Phase-Change Materials For Storage Of Heat

    NASA Technical Reports Server (NTRS)

    Colvin, David P.

    1989-01-01

    Report describes research on engineering issues related to storage and transport of heat in slurries containing phase-change materials in microscopic capsules. Specific goal of project to develop lightweight, compact, heat-management systems used safely in inhabited areas of spacecraft. Further development of obvious potential of technology expected to lead to commercialization and use in aircraft, electronic equipment, machinery, industrial processes, and other sytems in which requirements for management of heat compete with severe restrictions on weight or volume.

  13. Aquifer thermal energy (heat and chill) storage

    SciTech Connect

    Jenne, E.A. (ed.)

    1992-11-01

    As part of the 1992 Intersociety Conversion Engineering Conference, held in San Diego, California, August 3--7, 1992, the Seasonal Thermal Energy Storage Program coordinated five sessions dealing specifically with aquifer thermal energy storage technologies (ATES). Researchers from Sweden, The Netherlands, Germany, Switzerland, Denmark, Canada, and the United States presented papers on a variety of ATES related topics. With special permission from the Society of Automotive Engineers, host society for the 1992 IECEC, these papers are being republished here as a standalone summary of ATES technology status. Individual papers are indexed separately.

  14. Heat Transfer Analysis of a Packed Bed-PCM Capsules Latent Heat Thermal Energy Storage System

    Microsoft Academic Search

    Z. S. Abdel-Rehim

    2011-01-01

    Heat transfer analysis of a packed bed-PCM latent heat thermal energy storage system is presented in this study. The packed bed cylindrical column is filled with spherical capsules of PCM (paraffin wax) that is used for a solar water heating application. In this study, the physical model is developed to use for analyzing the thermal performance of packed bed-PCM latent

  15. Analysis and summary of a solar air collector-groundwater heat storage-greenhouse heating system

    Microsoft Academic Search

    A. C. Dale; V. M. Puri; J. R. Barrett; P. A. Hammer

    1981-01-01

    An air-type solar energy collector with reflective wings at the top and bottom was developed and adapted to heat a soil and groundwater heat storage from which energy was reclaimed to heat a greenhouse. Collector efficiency correlation for summer and winter months are presented for seasonal collector tilts of 30° and 60°, respectively. The collector performance data and correlations show

  16. Optimization of solar district heating systems: seasonal storage, heat pumps, and cogeneration

    Microsoft Academic Search

    D. Lindenberger; T. Bruckner; H.-M. Groscurth; R. Kummel

    2000-01-01

    The dynamic energy, emission, and cost optimization model deeco is further developed and applied to the analysis of solar district heating systems with seasonal storage in a pilot project of the Bavarian Research Foundation. The optimum integration of condensing boilers, compression and absorption heat pumps, and cogeneration of heat and power is computed for 100 well insulated housing units with

  17. Studies of Phase Change Materials and a Latent Heat Storage Unit Used for a Natural Circulation Cooling/Latent Heat Storage System

    NASA Astrophysics Data System (ADS)

    Sakitani, Katsumi; Honda, Hiroshi

    Experimental and theoretical studies were made of the heat transfer characteristics of a latent heat storage unit used for a natural circulation cooling /latent heat storage system. Heating and cooling curves of the latent heat storage unit undergoing solid-liquid phase change of a PCM (lauric acid) was obtained by using anatural circulation loop of R22 which consisted of an electrically heated evaporater, a water cooled condenser and the latent heat storage unit. The latent heat storage unit showed a heat transfer performance which was high enough for practical use. An approximate theoretical analysis was conducted to investigate transient behavior of the latent heat storage unit. Predictions of the refrigerant and outer surface temperatures during the melting process were in fair agreement with the experimental data, whereas that of the refrigerant temperature during the solidification process was considerably lower than the measurement.

  18. Utilization of heat pipes for transfer heat from the flue gas into the heat transfer medium

    NASA Astrophysics Data System (ADS)

    Lenhard, Richard; Kaduchová, Katarína; Papu?ík, Štefan; Janda?ka, Jozef

    2014-03-01

    The contribution is listed possible application of heat pipes in systems for obtaining heat from flue gas of small heat sources. It is also stated in the contribution design an experimental device on which to study the impact of fill (the quantity, type of load) at various temperature parameters (temperature heating and cooling) thermal power transferred to the heat pipe. Is listed measurement methodology using heat pipes designed experimental facility, measurement results and analysis of the results obtained.

  19. Heat loading limits for solid transuranic wastes storage

    SciTech Connect

    Spatz, T.L.

    1993-07-01

    Heat loading limits have been established for four storage configurations of TRU wastes. The calculations were performed assuming the worst case scenario whereby all the heat generated within a drum was generated within one ``cut`` and that this cut was located in the very center of the drum. Poly-boxes containing one HEPA filter were assumed to have a uniform heat generation throughout the filter. The maximum allowable temperatures were based on the materials in the containers. A comparison between the drum center temperature for a uniform heat load distribution and for the center temperature when the heat load is confined to one cut in the center of the drum is also illustrated. This comparison showed that the heat load of a particular drum can be more than doubled by distributing the sources of heat uniformly throughout the container.

  20. Earth's Energy Imbalance and Ocean Heat Storage

    NASA Astrophysics Data System (ADS)

    Hansen, J.; Willis, J.; Leuliette, E.; Bleck, R.; Lo, K.; Ruedy, R.; Sato, M.; Sun, S.

    2006-12-01

    The Earth's energy imbalance, i.e., the difference between solar energy absorbed and thermal energy emitted by the planet, is fundamental to global climate change, as it measures the net forcing acting on the climate system. The imbalance is now positive on decadal time scales, due to dominance of increasing greenhouse gas (GHG) forcing, and, with canonical climate sensitivity, it yields an estimate of the amount of global warming that remains "in the pipeline" due to GHGs already in the atmosphere. The ocean is the largest sink for excess incoming energy. Inference of information from the energy imbalance is affected by a trade-off between decreasing accuracy of earlier data and the added information from longer time scales. We use two atmosphere-ocean models, with ocean heat and sea level measurements, to study the roles of different climate forcings, unforced climate variability including ocean- cloud interactions, and limitations of data sampling. We find that observed decrease in ocean heat content in the upper 750m in 2004-2005 does not significantly alter the estimate of ~0.5C global warming still "in the pipeline". Continuation and refinement of measurements of ocean heat, sea level, and ice sheet mass balance have the potential to greatly refine understanding of global warming, its practical implications, and important climate processes, but to be most useful they need to be supplemented by better measurements of deep ocean heat content changes and precise measurements of changing climate forcings such as tropospheric aerosols.

  1. Energy and Exergy Efficiency of a Packed-bed Heat Storage Unit for Greenhouse Heating

    Microsoft Academic Search

    H. H Öztürk; A Ba?çetinçelik

    2003-01-01

    In this research, solar energy was stored daily using the volcanic material with the sensible heat technique for heating the tunnel greenhouse of 120m2. The external heat collection unit consisted of 27m2 of south-facing solar air heaters mounted at a 55° tilt angle. The dimensions of the packed-bed heat storage unit were 6m by 2m by 0·6m deep. The packed-bed

  2. Solar thermal energy storage using heat of dilution - Analysis of heat generation in multistage mixing column

    Microsoft Academic Search

    T. Tanaka; K. Sakuta; M. Kamimoto; T. Tani; S. Sawata; T. Horigome

    1978-01-01

    Heat recovery obtained after storage of solar energy in the form of heat of dilution is studied by analyzing the mixing of two liquids (H2SO4 and H2O) in two multistage mixing column systems. The thermal analysis shows that heat at various temperatures can be produced by heat of dilution in a manner useful for various energy supply systems. Enthalpy balances

  3. Heat pipe solar receiver with thermal energy storage

    NASA Technical Reports Server (NTRS)

    Zimmerman, W. F.

    1981-01-01

    An HPSR Stirling engine generator system featuring latent heat thermal energy storge, excellent thermal stability and self regulating, effective thermal transport at low system delta T is described. The system was supported by component technology testing of heat pipes and of thermal storage and energy transport models which define the expected performance of the system. Preliminary and detailed design efforts were completed and manufacturing of HPSR components has begun.

  4. Heat retaining integrated collector\\/storage solar water heaters

    Microsoft Academic Search

    M. Smyth; P. C. Eames; B. Norton

    2003-01-01

    An integrated collector\\/storage solar water heater (ICSSWH) that can significantly reduce heat loss to ambient during non-collection periods has been developed. Two thirds of the ICS vessel is mounted within a concentrating cusp, McIntire ‘W’ modified concentrator and incorporates an inner heat retaining vessel. The remaining upper 1\\/3 of the vessel is situated outside the reflector cavity and is heavily

  5. Methanol based heat pumps for storage of solar thermal energy

    Microsoft Academic Search

    P. O'd. Offenhartz; F. C. Brown

    1979-01-01

    The thermochemical cycle for a solar thermal storage system based on the reaction of CaCl2 and CH3OH vapor is described. This cycle is capable of pumping heat for solar air conditioning at a COP of 0.6, or for solar space and domestic water heating at a COP of 1.6. The equilibrium and kinetics of the CaCl2-CH3OH system are described, along

  6. Heat transfer enhancement in water when used as PCM in thermal energy storage

    Microsoft Academic Search

    L. F. Cabeza; H. Mehling; S. Hiebler; F. Ziegler

    2002-01-01

    Efficient and reliable storage systems for thermal energy are an important requirement in many applications where heat demand and supply or availability do not coincide. Heat and cold stores can basically be divided in two groups. In sensible heat stores the temperature of the storage material is increased significantly. Latent heat stores, on the contrary, use a storage material that

  7. Efficient Heat Storage Materials: Metallic Composites Phase-Change Materials for High-Temperature Thermal Energy Storage

    SciTech Connect

    None

    2011-11-21

    HEATS Project: MIT is developing efficient heat storage materials for use in solar and nuclear power plants. Heat storage materials are critical to the energy storage process. In solar thermal storage systems, heat can be stored in these materials during the day and released at night—when the sun’s not out—to drive a turbine and produce electricity. In nuclear storage systems, heat can be stored in these materials at night and released to produce electricity during daytime peak-demand hours. MIT is designing nanostructured heat storage materials that can store a large amount of heat per unit mass and volume. To do this, MIT is using phase change materials, which absorb a large amount of latent heat to melt from solid to liquid. MIT’s heat storage materials are designed to melt at high temperatures and conduct heat well—this makes them efficient at storing and releasing heat and enhances the overall efficiency of the thermal storage and energy-generation process. MIT’s low-cost heat storage materials also have a long life cycle, which further enhances their efficiency.

  8. Thermal Energy Storage System Using a Technical Grade Paraffin Wax as Latent Heat Energy Storage Material

    Microsoft Academic Search

    Kamil Kaygusuz; Ahmet Sari

    2005-01-01

    The objective of this study was to experimentally establish thermal energy storage (TES) performance using a technical grade paraffin wax as a phase change material (PCM) in a vertical concentric pipe-in-pipe latent heat storage system. The melting and solidification temperature range of the paraffin was found as 38°C–43°C and 36°C–42°C, respectively. These values were well in agreement with the values

  9. Flexible storage medium for write-once optical tape

    NASA Technical Reports Server (NTRS)

    Strandjord, Andrew J. G.; Webb, Steven P.; Perettie, Donald J.; Cipriano, Robert A.

    1993-01-01

    A write-once data storage media was developed which is suitable for optical tape applications. The media is manufactured using a continuous film process to deposit a ternary alloy of tin, bismuth, and copper. This laser sensitive layer is sputter deposited onto commercial plastic web as a single-layer thin film. A second layer is sequentially deposited on top of the alloy to enhance the media performance and act as an abrasion resistant hard overcoat. The media was observed to have laser write sensitivities of less than 2.0 njoules/bit, carrier-to-noise levels of greater than 50dB's, modulation depths of approximately 100 percent, read-margins of greater than 35, uniform grain sizes of less than 200 Angstroms, and a media lifetime that exceeds 10 years. Prototype tape media was produced for use in the CREO drive system. The active and overcoat materials are first sputter deposited onto three mil PET film in a single pass through the vacuum coating system, and then converted down into multiple reels of 35mm x 880m tape. One mil PET film was also coated in this manner and then slit and packaged into 3480 tape cartridges.

  10. Solar heating systems design procedure for greenhouse with internal collection and sensible heat storage

    Microsoft Academic Search

    A. K. Lau; L. M. Staley

    1989-01-01

    A simplified design procedure for solar heating systems for greenhouses is presented. Computer modeling and simulations were carried out to analyze the effects of design variations in greenhouse construction and storage characteristics on long-term average system thermal performance. The key performance indices were defined in terms of the total solar contribution and solar heating fraction. The results of many simulations

  11. Heat transfer enhancement in latent heat thermal energy storage system by using the internally finned tube

    Microsoft Academic Search

    Yuwen Zhang; A. Faghri

    1996-01-01

    The heat transfer enhancement in the latent heat thermal energy storage system by using an internally finned tube is presented in this paper. The phase change material fills the annular shell space around the tube, while the transfer fluid flows within the internally finned tube. The melting of the phase change material is described by a temperature transforming model coupled

  12. Transient behavior of heat pipe with thermal energy storage under pulse heat loads

    NASA Astrophysics Data System (ADS)

    Chang, Ming-, Jr.

    1991-02-01

    Future space missions will require thermal transport devices with the ability to handle transient pulse heat loads. A novel design of a high-temperature axially grooved heat pipe (HP) which incorporates thermal energy storage (TES) to migrate pulse heat loads was presented. A phase-change material (PCM) which is encapsulated in cylindrical containers was used for the thermal energy storage. The transient response of the HP/TES system under two different types of pulse heat loads was studied analytically. The first type is pulse heat loads applied at the heat pipe evaporator, the second type is reversed-pulse heat loads applied at the condenser. In this research, a new three-dimensional alternating-direction-implicit (ADI) method was developed to model the heat conduction through the heat pipe wall and wicks, including the liquid flow in grooves. A very important characteristic of this new ADI method is that it is consistent with physical considerations. Compared with the well-known Brian's and Douglas's ADI methods, this new ADI method had higher accuracy and requires less computer storage. In the numerical solution of heat transfer problems with phase change (Stefan-type problem), a modified Pham's method which includes features from enthalpy and heat capacity methods was used to simulate the melting and solidification processes of the PCG. The vapor flow was assumed quasi-steady and one-dimensional, and was coupled with the evaporation and condensation on the heat pipe inside wall surface and the surfaces of the PCM containers. The transient responses of three different HP/TES configurations were compared: (1) a heat pipe with a large empty cylinder installed in the vapor core, (2) a heat pipe with a large PCM cylinder, and (3) a heat pipe with six small PCM cylinders. From the numerical results, it was found that the PCM is very effective in mitigrating the adverse effect of pulse heat loads. The six small PCM cylinders are more efficient than the large PCM cylinder in relaxing the heat pipe temperature increase under pulse heat loads. Also, the small PCM cylinders can handle periodic, pulse heat loads better because the small PCM cylinders can solidify faster after each periodic, pulse heat load is terminated. A simple lumped-heat-capacity model was also used to predict the transient behavior of the heat pipe without PCM. Compared with the results from the finite-difference solution, it was found that the lumped model can predict the average heat pipe temperature and the heat input/output as the evaporator and condenser for the heat pipe without PCM quite well.

  13. A novel underground solar thermal heat storage unit cum heat exchanger for non air-conditioned buildings

    Microsoft Academic Search

    Rakesh Kumar; S. C. Kaushik

    2003-01-01

    A novel passive space conditioning configuration is presented, integrating a Solar Collector System, Underground Storage Tank and Novel Heat Exchanger. This Underground Solar Thermal Heat Exchanger (USTHE) provided improved sensible heating\\/cooling of air by employing a Novel Heat Exchanger (NHX). The dynamic performance of the storage tank in USTHE is modelled using the finite difference method accounting thermal stratification of

  14. A second law analysis of a thermal energy storage system with Joulean heating of the storage element

    Microsoft Academic Search

    Krane

    1985-01-01

    The techniques of Second Law analysis are applied to the optimal design of a thermal energy storage system with Joulean heaters. The resulting model accounts for three major sources of entropy generation: (1) Joulean heating, (2) heat transfer through finite temperature differences between the gas in the heat exchanger duct and the storage element, and (3) viscous losses in the

  15. Conversion of medium and low temperature heat to power

    NASA Astrophysics Data System (ADS)

    Fischer, Johann; Wendland, Martin; Lai, Ngoc Anh

    2013-04-01

    Presently most electricity is produced in power plants which use high temperature heat supplied by coal, oil, gas or nuclear fission and Clausius-Rankine cycles (CRC) with water as working fluid (WF). On the other hand, geo-, solar-, ocean-, and biogenic-heat have medium and low temperatures. At these temperatures, however, the use of other WF and/or other cycles can yield higher efficiencies than those of the water-CRC. For an assessment of the efficiency we model systems which include the heat transfer to and from the WF and the cycle. Optimization criterion is the exergy efficiency defined as the ratio of the net power output to the incoming exergy flow of the heat carrier. First, for a better understanding we discuss some thermodynamic properties of the WFs: 1) the critical point parameters, 2) the shape of the vapour- liquid coexistence curve in the temperature vs entropy (T,s)-diagram which may be either bell-shaped or overhanging [1,2], and 3) the shape of sub- and supercritical isobars for pure fluids and fluid mixtures. Second, we show that the problems of a CRC with water at lower temperatures are 1) the shape of the T,s-diagram and 2) the exergy loss during heat transfer to the WF. The first problem can be overcome by using an organic working fluid in the CRC which then is called organic Rankine cycle (ORC). The second problem is reduced by supercritical organic Rankine cycles (sORC) [1,2], trilateral cycles (TLC) and the more general power-flash cycles (PFC) [2], and organic flash cycles (OFC) [3]. Next, selected results for systems with the above mentioned cycles will be presented. The heat carrier inlet temperatures THC range from 120°C to 350°C.The pure working fluids are water, refrigerants, alkanes, aromates and siloxanes and have to be selected to match with THC. It is found that TLC with water have the highest efficiencies but show very large volume flows at lower temperatures. Moreover, expansion machines for TLC and PFC are still under improvement. Presently, the best feasible systems seem to be ORC cycles using WF with a nearly vertical dew line in the T,s-diagram as HFO-1234yf, n-butane or cyclopentane and upper pressures close below or above (sORC) the critical pressure. Finally, we will consider the above cycles also with mixtures as WF including the Kalina cycle and coupled processes like cascade or multistage processes. [1] B Saleh, G Koglbauer, M Wendland, J Fischer, Working fluids for low temperature ORC-processes, Energy 32, 1210-21 (2007). [2] N A Lai, J Fischer, Efficiencies of Power Flash Cycles, Energy 44, 1017-27 (2012). [3] T Ho, S S Mao, R Greif, Comparison of the Organic Flash Cycle (OFC) to other advanced vapor cycles for intermediate and high temperature waste heat reclamation and solar thermal energy, Energy 42, 213-23 (2012).

  16. Heat and storage effects on the flavour of peanuts.

    PubMed

    el-Kayati, S M; Fadel, H H; Abdel Mageed, M; Farghal, S A

    1998-12-01

    Two peanut varieties, Giza 4 and Giza 5 were subjected to different heat treatments such as drying in solar drier at air speed 0.5 and 2 m/sec with average temperature 45 and 60 degrees C and heating in oven at 120 and 150 degrees C. The sensory evaluation of the two varieties showed insignificant differences among varieties and heating processes. A correlation between the sensory and instrumental data was found. The high sensory scores of samples heated at 150 degrees C were attributed to the presence of high concentration of pyrazines which were thought to contribute to flavour and aroma of fresh roasted peanut. A comparative study between the main chemical classes retained in peanut samples after storage for 3 months at room temperature showed that the aldehydes derived lipids increased significantly in the solar dried samples. The antioxidative components produced via Maillard reaction resulted in oxidative stability of the samples heated in oven. PMID:9881373

  17. Prolonging storage time of baby ginger by using a sand-based storage medium and essential oil treatment.

    PubMed

    Liu, Ji; Sui, Guoliang; He, Yongzhou; Liu, Dongjie; Yan, Jing; Liu, Shuxiang; Qin, Wen

    2014-04-01

    Wilt and rot occur readily during storage of baby ginger because of its tender skin and high moisture content (MC). A storage medium, which consisted of sand, 20% water, and 3.75% super absorbent polymers delayed weight loss and loss of firmness at 12 °C and 90% relative humidity. Microorganisms were isolated and purified from decayed rhizomes; among these, 3 fungi were identified as pathogens. The results of 18S rDNA sequence analysis showed that these fungi belonged to Penicillium, Fusarium, and Mortierella genera. The use of essential oil for controlling these pathogens was then investigated in vitro. Essential oils extracted from Cinnamomum zeylanicum (cinnamon) and Thymus vulgaris (thyme) completely inhibited the growth of all of the above pathogens at a concentration of 2000 ppm. Cinnamon oil showed higher antifungal activity in the drug sensitivity test with minimal fungicidal concentration (<500 ppm against all pathogens). In the in vivo test, cinnamon fumigation at a concentration of 500 ppm reduced infection rates of Penicillium, Fusarium, and Mortierella by 50.3%, 54.3%, and 60.7%, respectively. We recommended cinnamon oil fumigation combined with medium storage at 12 °C as an integrated approach to baby ginger storage. PMID:24547773

  18. Dual-medium thermal storage system for solar thermal power plants

    Microsoft Academic Search

    R. C. Mitchell; G. R. Morgan; W. Unterberg

    1977-01-01

    The application of a dual medium thermal storage system to the ERDA 10 megawatt electrical pilot plant and to subsequent commercial plants of 100 MWe and larger is discussed. The system uses a low-cost stationary solid bed to store most of the energy, with a suitable liquid to transfer energy into and out of the bed (and to store part

  19. The concrete columns as a sensible thermal energy storage medium and a heater

    NASA Astrophysics Data System (ADS)

    Ünalan, Sebahattin; Özrahat, Evrim

    2014-08-01

    This study investigated storage possibility of sensible thermal energy in the concrete columns of multi-storey buildings and the heating performance of the indoors with the stored energy. In the suggested system, the dry air heated in an energy center will be circulated in stainless steel pipes through columns. The sensible thermal energy would firstly be stored by means of forced convection in column medium. Then, the stored thermal energy will transfer by natural convection and radiation from the column surfaces to indoor spaces. The transient thermal calculations are realized for a flat of the 11-storey building in Kayseri city of Turkey. The thermal energy requirement of the flat is nearby 5.3 kW as an average of a winter season. The simplified transient calculations were carried out over a concrete hollow cylindrical column having outer radius of 0.31 m and inner radius of 0.05 m corresponding an averaged column section in the sample flat. The flow temperature was selected between T = 350 and 500 K, which are considerably lower than the temperature of 573 K assumed as a limit for thermal strength of the concrete in the literature. The flow velocity ranges were selected between V = 1.0 and 5.0 m/s. The initial temperature was assumed as 293 K. After the first energy charging process of 23 h, for T = 350 K and V = 1.0 m/s, the total heat flux from the column surfaces into indoors are nearby 5.5 kW. The first charging time required to reach the energy requirement of 5.3 kW is decreased by increasing the flow velocity and temperature. Also for 5.0 m/s-350 K and 5.0 m/s-450 K, this time can decrease to 10 and 4.5 h, respectively. In addition, with 4.0 m/s-360 K or 2.0 m/s-400 K, after the energy charging of 8 h, the energy requirement of 5.3 kW can be provided by the energy discharging of 16 h and the energy charging of 8 h during 7 days. The results are very attractive in terms of the building heating systems of the future.

  20. Candidate thermal energy storage technologies for solar industrial process heat applications

    NASA Technical Reports Server (NTRS)

    Furman, E. R.

    1979-01-01

    A number of candidate thermal energy storage system elements were identified as having the potential for the successful application of solar industrial process heat. These elements which include storage media, containment and heat exchange are shown.

  1. Thermodynamics of heat storage in a PCM shell-and-tube heat exchanger in parallel or in series with a heat engine

    Microsoft Academic Search

    M. Conti; Ch. Charach

    1996-01-01

    This paper addresses the thermodynamics of heat storage in a PCM shell-and-tube heat exchanger, which in a solar power plant is provided to damp the pulsed behaviour of the heat source. Unequal duration of the active and passive phases of the heat source, and consequently of the heat storage and discharge, is allowed. Two alternative schemes of connection of the

  2. Heat pipe cooling system for underground, radioactive waste storage tanks

    SciTech Connect

    Cooper, K.C.; Prenger, F.C.

    1980-02-01

    An array of 37 heat pipes inserted through the central hole at the top of a radioactive waste storage tank will remove 100,000 Btu/h with a heat sink of 70/sup 0/F atmospheric air. Heat transfer inside the tank to the heat pipe is by natural convection. Heat rejection to outside air utilizes a blower to force air past the heat pipe condenser. The heat pipe evaporator section is axially finned, and is constructed of stainless steel. The working fluid is ammonia. The finned pipes are individually shrouded and extend 35 ft down into the tank air space. The hot tank air enters the shroud at the top of the tank and flows downward as it is cooled, with the resulting increased density furnishing the pressure difference for circulation. The cooled air discharges at the center of the tank above the sludge surface, flows radially outward, and picks up heat from the radioactive sludge. At the tank wall the heated air rises and then flows inward to comple the cycle.

  3. Heat pipe based cold energy storage systems for datacenter energy conservation

    Microsoft Academic Search

    Randeep Singh; Masataka Mochizuki; Koichi Mashiko; Thang Nguyen

    2011-01-01

    In the present paper, design and economics of the novel type of thermal control system for datacenter using heat pipe based cold energy storage has been proposed and discussed. Two types of cold energy storage system namely: ice storage system and cold water storage system are explained and sized for datacenter with heat output capacity of 8800 kW. Basically, the cold

  4. New CLIVAR research focus: Consistency between planetary heat balance and ocean heat storage

    NASA Astrophysics Data System (ADS)

    von Schuckmann, Karina; Visbeck, Martin; Haines, Keith; Mathieu, Pierre-Philippe; Gulev, Sergey; Barnier, Bernard; Trenberth, Kevin; Clayson, Carol Anne; Loeb, Norman; Palmer, Matthew

    2014-05-01

    Climate is very much about exchange of energy in the Earth System, and in particular in the form of heat. Quantifying these exchanges and how it affects our climate system is one of the key challenges faced by the climate research community. In this context, the Ocean-climate system - Variability, Predictability and Change (CLIVAR) project of the World Climate Research Programme (WCRP) has recently established a new research focus on "Consistency between Planetary Heat Balance and Ocean Heat Storage ". The main objective of the CLIVAR cross-cutting activity is to better understand the "role of the ocean in energy uptake " by analyzing consistency of heat budget components as seen by independent global observing systems, including (i) Earth Observation (EO) satellite data, (ii) in-situ measurements of ocean heat content storage changes, and (iii) Ocean reanalysis for heat transports and exchanges. The project aims at a refinement of a scientific framework on consistency between planetary heat balance and ocean heat storage; the evaluation of existing data sets and information products, their uncertainties and their consistency; recommendations on how to improve the observing systems and derived information products, assimilation methods, ocean and climate models and surface fluxes; contributing insights to related climate research topics such as anthropogenic climate change, seasonal climate prediction, decadal variability, predictability and prediction, as well as sea-level variability and change.

  5. Active heat exchange system development for latent heat thermal energy storage

    NASA Technical Reports Server (NTRS)

    Lefrois, R. T.; Knowles, G. R.; Mathur, A. K.; Budimir, J.

    1979-01-01

    Active heat exchange concepts for use with thermal energy storage systems in the temperature range of 250 C to 350 C, using the heat of fusion of molten salts for storing thermal energy are described. Salt mixtures that freeze and melt in appropriate ranges are identified and are evaluated for physico-chemical, economic, corrosive and safety characteristics. Eight active heat exchange concepts for heat transfer during solidification are conceived and conceptually designed for use with selected storage media. The concepts are analyzed for their scalability, maintenance, safety, technological development and costs. A model for estimating and scaling storage system costs is developed and is used for economic evaluation of salt mixtures and heat exchange concepts for a large scale application. The importance of comparing salts and heat exchange concepts on a total system cost basis, rather than the component cost basis alone, is pointed out. The heat exchange concepts were sized and compared for 6.5 MPa/281 C steam conditions and a 1000 MW(t) heat rate for six hours. A cost sensitivity analysis for other design conditions is also carried out.

  6. Heat storage system utilizing phase change materials government rights

    DOEpatents

    Salyer, Ival O. (Dayton, OH)

    2000-09-12

    A thermal energy transport and storage system is provided which includes an evaporator containing a mixture of a first phase change material and a silica powder, and a condenser containing a second phase change material. The silica powder/PCM mixture absorbs heat energy from a source such as a solar collector such that the phase change material forms a vapor which is transported from the evaporator to the condenser, where the second phase change material melts and stores the heat energy, then releases the energy to an environmental space via a heat exchanger. The vapor is condensed to a liquid which is transported back to the evaporator. The system allows the repeated transfer of thermal energy using the heat of vaporization and condensation of the phase change material.

  7. Patterned medium for heat assisted magnetic recording Krat endur1,a

    E-print Network

    Yanikoglu, Berrin

    Patterned medium for heat assisted magnetic recording Kürat endur1,a and William Challener2 1 magnetic recording HAMR is a potential solution to extend the limits of conventional magnetic recording of the magnetic medium. In this letter we suggest a recording medium that provides a significant enhancement

  8. (Thermal energy storage technologies for heating and cooling applications)

    SciTech Connect

    Tomlinson, J.J.

    1990-12-19

    Recent results from selected TES research activities in Germany and Sweden under an associated IEA annex are discussed. In addition, several new technologies for heating and cooling of buildings and automobiles were reviewed and found to benefit similar efforts in the United states. Details of a meeting with Didier-Werke AG, a leading German ceramics manufacturer who will provide TES media necessary for the United States to complete field tests of an advanced high temperature latent heat storage material, are presented. Finally, an overview of the December 1990 IEA Executive Committee deliberations on TES is presented.

  9. Assessing a novel room temperature DNA storage medium for forensic biological samples.

    PubMed

    Lee, Steven B; Clabaugh, Kimberly C; Silva, Brie; Odigie, Kingsley O; Coble, Michael D; Loreille, Odile; Scheible, Melissa; Fourney, Ron M; Stevens, Jesse; Carmody, George R; Parsons, Thomas J; Pozder, Arijana; Eisenberg, Arthur J; Budowle, Bruce; Ahmad, Taha; Miller, Russell W; Crouse, Cecelia A

    2012-01-01

    The ability to properly collect, analyze and preserve biological stains is important to preserving the integrity of forensic evidence. Stabilization of intact biological evidence in cells and the DNA extracts from them is particularly important since testing is generally not performed immediately following collection. Furthermore, retesting of stored DNA samples may be needed in casework for replicate testing, confirmation of results, and to accommodate future testing with new technologies. A novel room temperature DNA storage medium, SampleMatrix™ (SM; Biomatrica, Inc., San Diego, CA), was evaluated for stabilizing and protecting samples. Human genomic DNA samples at varying amounts (0.0625-200 ng) were stored dry in SM for 1 day to 1 year under varying conditions that included a typical ambient laboratory environment and also through successive freeze-thaw cycles (3 cycles). In addition, spiking of 1-4 × SM into samples prior to analysis was performed to determine any inhibitory effects of SM. Quantification of recovered DNA following storage was determined by quantitative PCR or by agarose gel electrophoresis, and evaluation of quantitative peak height results from multiplex short tandem repeat (STR) analyses were performed to assess the efficacy of SM for preserving DNA. Results indicate no substantial differences between the quality of samples stored frozen in liquid and those samples maintained dry at ambient temperatures protected in SM. For long-term storage and the storage of low concentration samples, SM provided a significant advantage over freezer storage through higher DNA recovery. No detectable inhibition of amplification was observed at the recommended SM concentration and complete profiles were obtained from genomic DNA samples even in the presence of higher than recommended concentrations of the SM storage medium. The ability to stabilize and protect DNA from degradation at ambient temperatures for extended time periods could have tremendous impact in simplifying and improving sample storage conditions and requirements. The current work focuses on forensics analysis; however this technology is applicable to all endeavors requiring storage of DNA. PMID:21324769

  10. Studies of Phase Change Materials and a Latent Heat Storage Unit Used for a Natural Circulation Cooling/Latent Heat Storage System

    NASA Astrophysics Data System (ADS)

    Sakitani, Katsumi; Honda, Hiroshi

    Experiments were performed to investigate feasibility of using organic materials as a PCM for a latent heat storage unit of a natural circulation cooling/latent heat storage system. This system was designed to cool a shelter accommodating telecommunication equipment located in subtropical deserts or similar regions without using a power source. Taking into account practical considerations and the results of various experiments regarding the thermodynamic properties, thermal degradation, and corrosiveness to metals, lauric acid and iron was selected for the PCM and the latent heat storage unit material, respectively. Cyclic heating and cooling of the latent heat storage unit undergoing solid-liquid phase change was repeated for more than 430 days. The results showed that the heating-cooling curve was almost unchanged between the early stage and the 1,870th cycle. It was concluded that the latent heat storage unit could be used safely for more than ten years as a component of the cooling system.

  11. Analysis of selected surface characteristics and latent heat storage for passive solar space heating

    SciTech Connect

    Fthenakis, V.; Leigh, R.

    1981-12-01

    Results are presented of an analysis of the value of various technical improvements in the solar collector and thermal storage subsystems of passive solar residential, agricultural, and industrial systems for two regions of the country. The evaluated improvements are: decreased emissivity and increased absorptivity of absorbing surfaces, decreased reflectivity, and decreased emissivity of glazing surface, and the substitution of sensible heat storage media with phase change materials. The value of each improvement is estimated by the additional energy savings resulting from the improvement.

  12. Integrated heat exchanger design for a cryogenic storage tank

    NASA Astrophysics Data System (ADS)

    Fesmire, J. E.; Tomsik, T. M.; Bonner, T.; Oliveira, J. M.; Conyers, H. J.; Johnson, W. L.; Notardonato, W. U.

    2014-01-01

    Field demonstrations of liquid hydrogen technology will be undertaken for the proliferation of advanced methods and applications in the use of cryofuels. Advancements in the use of cryofuels for transportation on Earth, from Earth, or in space are envisioned for automobiles, aircraft, rockets, and spacecraft. These advancements rely on practical ways of storage, transfer, and handling of liquid hydrogen. Focusing on storage, an integrated heat exchanger system has been designed for incorporation with an existing storage tank and a reverse Brayton cycle helium refrigerator of capacity 850 watts at 20 K. The storage tank is a 125,000-liter capacity horizontal cylindrical tank, with vacuum jacket and multilayer insulation, and a small 0.6-meter diameter manway opening. Addressed are the specific design challenges associated with the small opening, complete modularity, pressure systems re-certification for lower temperature and pressure service associated with hydrogen densification, and a large 8:1 length-to-diameter ratio for distribution of the cryogenic refrigeration. The approach, problem solving, and system design and analysis for integrated heat exchanger are detailed and discussed. Implications for future space launch facilities are also identified. The objective of the field demonstration will be to test various zero-loss and densified cryofuel handling concepts for future transportation applications.

  13. Integrated heat exchanger design for a cryogenic storage tank

    SciTech Connect

    Fesmire, J. E.; Bonner, T.; Oliveira, J. M.; Johnson, W. L.; Notardonato, W. U. [NASA Kennedy Space Center, Cryogenics Test Laboratory, NE-F6, KSC, FL 32899 (United States); Tomsik, T. M. [NASA Glenn Research Center, 21000 Brookpark Road, Cleveland, OH 44135 (United States); Conyers, H. J. [NASA Stennis Space Center, Building 3225, SSC, MS 39529 (United States)

    2014-01-29

    Field demonstrations of liquid hydrogen technology will be undertaken for the proliferation of advanced methods and applications in the use of cryofuels. Advancements in the use of cryofuels for transportation on Earth, from Earth, or in space are envisioned for automobiles, aircraft, rockets, and spacecraft. These advancements rely on practical ways of storage, transfer, and handling of liquid hydrogen. Focusing on storage, an integrated heat exchanger system has been designed for incorporation with an existing storage tank and a reverse Brayton cycle helium refrigerator of capacity 850 watts at 20 K. The storage tank is a 125,000-liter capacity horizontal cylindrical tank, with vacuum jacket and multilayer insulation, and a small 0.6-meter diameter manway opening. Addressed are the specific design challenges associated with the small opening, complete modularity, pressure systems re-certification for lower temperature and pressure service associated with hydrogen densification, and a large 8:1 length-to-diameter ratio for distribution of the cryogenic refrigeration. The approach, problem solving, and system design and analysis for integrated heat exchanger are detailed and discussed. Implications for future space launch facilities are also identified. The objective of the field demonstration will be to test various zero-loss and densified cryofuel handling concepts for future transportation applications.

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

    NASA Astrophysics Data System (ADS)

    Wells, N. C.

    2012-04-01

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

  15. Integral collector storage system with heat exchange apparatus

    DOEpatents

    Rhodes, Richard O.

    2004-04-20

    The present invention relates to an integral solar energy collector storage systems. Generally, an integral collector storage system includes a tank system, a plurality of heat exchange tubes with at least some of the heat exchange tubes arranged within the tank system, a first glazing layer positioned over the tank system and a base plate positioned under the tank system. In one aspect of the invention, the tank system, the first glazing layer an the base plate each include protrusions and a clip is provided to hold the layers together. In another aspect of the invention, the first glazing layer and the base plate are ribbed to provide structural support. This arrangement is particularly useful when these components are formed from plastic. In yet another aspect of the invention, the tank system has a plurality of interconnected tank chambers formed from tubes. In this aspect, a supply header pipe and a fluid return header pipe are provided at a first end of the tank system. The heat exchange tubes have inlets coupled to the supply header pipe and outlets coupled to the return header pipe. With this arrangement, the heat exchange tubes may be inserted into the tank chambers from the first end of the tank system.

  16. Second law optimization of a sensible heat thermal energy storage system with a distributed storage element. Part 1

    Microsoft Academic Search

    M. J. Taylor; R. J. Krane; J. R. Parsons

    1991-01-01

    This paper explores the behavior of a flat- slab, sensible heat thermal energy storage system, the physical design and operation of which have been optimized to minimize the production of entropy by thermodynamic irreversibilities. Unlike many previous studies, the present work includes the entropy production by transient heat conduction within the storage element; that is, the analytical model is based

  17. Heat storage device for pre-heating internal combustion engines at start-up

    Microsoft Academic Search

    Leonard L Vasiliev; Viktor S Burak; Andrei G Kulakov; Donatas A Mishkinis; Pavel V Bohan

    1999-01-01

    The development of heat storage (HS) devices for pre-heating internal-combustion engines at start-up is presented as an extremely urgent problem. The absence of warm garages and the above-average depreciation of automotive machinery, especially urban buses, force maintenance organisations to search for new ways to facilitate engine start-up in cold periods. In this work, a thermal accumulator (HS) working on the

  18. Experimental simulation of latent heat thermal energy storage and heat pipe thermal transport for dish concentrator solar receiver

    NASA Technical Reports Server (NTRS)

    Narayanan, R.; Zimmerman, W. F.; Poon, P. T. Y.

    1981-01-01

    Test results on a modular simulation of the thermal transport and heat storage characteristics of a heat pipe solar receiver (HPSR) with thermal energy storage (TES) are presented. The HPSR features a 15-25 kWe Stirling engine power conversion system at the focal point of a parabolic dish concentrator operating at 827 C. The system collects and retrieves solar heat with sodium pipes and stores the heat in NaF-MgF2 latent heat storage material. The trials were run with a single full scale heat pipe, three full scale TES containers, and an air-cooled heat extraction coil to replace the Stirling engine heat exchanger. Charging and discharging, constant temperature operation, mixed mode operation, thermal inertial, etc. were studied. The heat pipe performance was verified, as were the thermal energy storage and discharge rates and isothermal discharges.

  19. Light storage in a tripod medium as a basis for logical operations

    NASA Astrophysics Data System (ADS)

    S?owik, K.; Raczy?ski, A.; Zaremba, J.; Zieli?ska-Kaniasty, S.

    2012-05-01

    A photon being a carrier of a polarization qubit is stored inside an atomic medium in the tripod configuration in the form of atomic excitations. Such stored information can be processed in the atomic memory and carried away by the released photon. An implementation is proposed of single qubit gates, e.g., phase, NOT, ?{NOT} and Hadamard, as well as for a two-qubit CNOT gate, operating on polarized photons and based on light storage.

  20. Thermal energy storage heat exchanger: Molten salt heat exchanger design for utility power plants

    Microsoft Academic Search

    A. Ferarra; G. Yenetchi; R. Haslett; R. Kosson

    1977-01-01

    The use of thermal energy storage (TES) in the latent heat of molten salts as a means of conserving fossil fuels and lowering the cost of electric power was evaluated. Public utility systems provided electric power on demand. This demand is generally maximum during late weekday afternoons, with considerably lower overnight and weekend loads. Typically, the average demand is only

  1. Numerical analysis of melting with constant heat flux heating in a thermal energy storage system

    Microsoft Academic Search

    Zhongliang Liu; Chongfang Ma

    2002-01-01

    Melting in a finite slab with a second kind boundary condition is studied numerically in order to simulate the charging process of a thermal energy storage system. A dimensionless model is given, from which it is concluded that the main factors that influence the melting process are the dimensionless heating flux, the modified Stefan number, the relative thermal diffusivity and

  2. High Temperature Metal Hydrides as Heat Storage Materials for Solar and Related Applications

    PubMed Central

    Felderhoff, Michael; Bogdanovi?, Borislav

    2009-01-01

    For the continuous production of electricity with solar heat power plants the storage of heat at a temperature level around 400 °C is essential. High temperature metal hydrides offer high heat storage capacities around this temperature. Based on Mg-compounds, these hydrides are in principle low-cost materials with excellent cycling stability. Relevant properties of these hydrides and their possible applications as heat storage materials are described. PMID:19333448

  3. Pomegranate Juice (Punica Granatum): A New Storage Medium for Avulsed Teeth

    PubMed Central

    Tavassoli-Hojjati, Sara; Aliasghar, Elham; Babaki, Fatemeh Ahmadian; Emadi, Fatemeh; Parsa, Maliheh; Tavajohi, Shohreh; Ahmadyar, Maryam; Ostad, Seyed Nasser

    2014-01-01

    Objective There is evidence indicating that pomegranate juice contains many of the essential properties necessary to retain cell viability and cell proliferation. These properties indicate that pomegranate juice is a suitable storage medium for avulsed teeth. However, this idea has not yet been tested. In this study, the capacity of pomegranate juice (PJ) as a storage medium for retaining avulsed teeth was evaluated. Materials and Methods: PDL fibroblasts were obtained from healthy human premolars and cultured in Dulbecco’s Modified Eagle’s Medium (DMEM). Cultured cells were subjected to different concentrations of pomegranate juice (PJ), 1% Hank’s balanced salt solution (HBSS) and tap water for 1, 3, 6 and 24 hours. PDL cell viability was assessed by the neutral red uptake assay. Results: The results indicated that 7.5% PJ was the most effective solution for maintaining PDL cell viability amongst all the experimental solution’s and time intervals (P<0.05). The results also showed that 1% PJ was as effective as HBSS for maintaining PDL cell viability. The amount of cell viability increased with increasing concentration of PJ at all time intervals (P<0.001). This effect is suggestive of the proliferative potential of PJ solution. Conclusion: In conclusion, PJ can be recommended as a suitable transport medium for avulsed teeth. PMID:24910699

  4. Evaluation of photobioreactor heat balance for predicting changes in culture medium temperature due to light irradiation.

    PubMed

    Morita, M; Watanabe, Y; Saiki, H

    2001-09-20

    Microalgal photosynthesis requires appropriate culture medium temperatures to achieve high photosynthetic performance and to maintain production of a high-quality biomass product. Enclosed systems, such as our conical, helical tubular photobioreactor (HTP), can accomplish high photosynthetic efficiency and the small amount of culture medium used by these systems means that the culture medium temperature may be effectively controlled. On the other hand, because a high ratio of surface area to culture medium volume leads to rapid heating under the illumination condition and substantial heat loss at night, maintaining a suitable culture medium temperature is necessary to achieve efficient, commercially practical biomass production. In order to predict changes in the culture medium temperature caused by changes in solar irradiance and ambient temperature, it is necessary to understand the heat balance within the photobioreactor. We therefore investigated the heat balance in three major parts (photostage, degasser, and helical heat exchanger) of our conical HTP, analyzed the time-dependent changes in medium temperature at various room temperatures and radiant energy inputs, and predicted changes in the culture medium temperature based on the characteristics of heat transfer among the three parts. Using this model, the predicted changes in culture medium temperature were very similar to the changes observed experimentally in the laboratory and under field conditions. This means that by calculating the time-dependent changes in the culture medium temperature, based on measurements of solar energy input and ambient temperature, we should be able to estimate the energy required to maintain the culture medium temperature within a range where photosynthetic performance of microalgae is high. PMID:11494213

  5. Current status of ground source heat pumps and underground thermal energy storage in Europe

    Microsoft Academic Search

    Burkhard Sanner; Constantine Karytsas; Dimitrios Mendrinos; Ladislaus Rybach

    2003-01-01

    Geothermal Heat Pumps, or Ground Coupled Heat Pumps (GCHP), are systems combining a heat pump with a ground heat exchanger (closed loop systems), or fed by ground water from a well (open loop systems). They use the earth as a heat source when operating in heating mode, with a fluid (usually water or a water–antifreeze mixture) as the medium that

  6. Central unresolved issues in thermal energy storage for building heating and cooling

    SciTech Connect

    Swet, C.J.; Baylin, F.

    1980-07-01

    This document explores the frontier of the rapidly expanding field of thermal energy storage, investigates unresolved issues, outlines research aimed at finding solutions, and suggests avenues meriting future research. Issues related to applications include value-based ranking of storage concepts, temperature constraints, consistency of assumptions, nomenclature and taxonomy, and screening criteria for materials. Issues related to technologies include assessing seasonal storage concepts, diurnal coolness storage, selection of hot-side storage concepts for cooling-only systems, phase-change storage in building materials, freeze protection for solar water heating systems, and justification of phase-change storage for active solar space heating.

  7. Advanced latent heat storage media for high-temperature industrial applications

    NASA Astrophysics Data System (ADS)

    Olszewski, M.

    1984-03-01

    Several advanced thermal energy storage (TES) media are being developed for high temperature industrial applications. One of the concepts involves a composite medium consisting of a phase-change carbonate salt supported and immobilized within a submicro sized capillary structure of a particulate ceramic matrix or porous sintered ceramic. Immobilization of the molten salt within the ceramic structure permits operation of the composite pellets, bricks, or other shapes in direct contact with compatible fluids. Energy storage occurs in both sensible and latent forms with the composite providing higher energy storage densities than standard sensible heat storage systems. The second concept centers on the development of a self-encapsulating metallic eutectic. This work focuses on metallic eutectics containing silicon. Starting with a silicon-rich mixture, it is feasible to develop a self-encapsulating pellet by cooling the liquid drops at a controlled rate. A solid of nearly pure silicon will form on the exterior of the pellet leaving a eutectic, phase change media in the interior. The concept are described and information concerning current development activities is presented.

  8. Thermal energy storage for industrial waste heat recovery

    NASA Technical Reports Server (NTRS)

    Hoffman, H. W.; Kedl, R. J.; Duscha, R. A.

    1978-01-01

    The potential is examined for waste heat recovery and reuse through thermal energy storage in five specific industrial categories: (1) primary aluminum, (2) cement, (3) food processing, (4) paper and pulp, and (5) iron and steel. Preliminary results from Phase 1 feasibility studies suggest energy savings through fossil fuel displacement approaching 0.1 quad/yr in the 1985 period. Early implementation of recovery technologies with minimal development appears likely in the food processing and paper and pulp industries; development of the other three categories, though equally desirable, will probably require a greater investment in time and dollars.

  9. Thermal storage for industrial process and reject heat

    NASA Technical Reports Server (NTRS)

    Duscha, R. A.; Masica, W. J.

    1978-01-01

    Industrial production uses about 40% of the total energy consumed in the United States. The major share of this is derived from fossil fuel. Potential savings of scarce fuel is possible through the use of thermal energy storage (TES) of reject or process heat for subsequent use. Results of study contracts awarded by the Department of Energy (DOE) and managed by the NASA Lewis Research Center have identified three especially significant industries where high temperature TES appears attractive - paper and pulp, iron and steel, and cement. Potential annual fuel savings with large scale implementation of near-term TES systems for these three industries is nearly 9 million bbl of oil.

  10. Heat transfer in vertically aligned phase change energy storage systems

    SciTech Connect

    El-Dessouky, H.T.; Bouhamra, W.S.; Ettouney, H.M.; Akbar, M. [Kuwait Univ., Safat (Kuwait). Dept. of Chemical Engineering

    1999-05-01

    Convection effects on heat transfer are analyzed in low temperature and vertically aligned phase change energy storage systems. This is performed by detailed temperature measurements in the phase change material (PCM) in eighteen locations forming a grid of six radial and three axial positions. The system constitutes a double pipe configuration, where commercial grade paraffin wax is stored in the annular space between the two pipes and water flows inside the inner pipe. Vertical alignment of the system allowed for reverse of the flow direction of the heat transfer fluid (HTF), which is water. Therefore, the PCM is heated from the bottom for HTF flow from bottom to top and from the top as the HTF flow direction is reversed. For the former case, natural convection affects the melting process. Collected data are used to study variations in the transient temperature distribution at axial and radial positions as well as for the two-dimensional temperature field. The data are used to calculate the PCM heat transfer coefficient and to develop correlations for the melting Fourier number. Results indicate that the PCM heat transfer coefficient is higher for the case of PCM heating from bottom to top. Nusselt number correlations are developed as a function of Rayleigh, Stefan, and Fourier numbers for the HTF flow from bottom to top and as a function of Stefan and Fourier numbers for HTF flow from top to bottom. The enhancement ratio for heat transfer caused by natural convection increases and then levels off as the inlet temperature of the HTF is increased.

  11. The Influence of Firing Medium or Low Heat Value Fuel on the Safe Operation of Gas Turbine

    Microsoft Academic Search

    Zhang Xuelei; Wang Songling; Chen Haiping; Zhou Lanxin

    2010-01-01

    Medium or low heat value fuels are very rich in China, and they can be used to generate electric power. Five strategies were obtained when gas turbine firing medium or low heat value fuel. Take coke oven gas and coal-based syngas as an example, the influence of firing medium or low heat value fuel on safe operation of gas turbine

  12. Heat Transfer and Latent Heat Storage in Inorganic Molten Salts for Concentrating Solar Power Plants

    SciTech Connect

    Mathur, Anoop [Terrafore Inc.] [Terrafore Inc.

    2013-08-14

    A key technological issue facing the success of future Concentrating Solar Thermal Power (CSP) plants is creating an economical Thermal Energy Storage (TES) system. Current TES systems use either sensible heat in fluids such as oil, or molten salts, or use thermal stratification in a dual-media consisting of a solid and a heat-transfer fluid. However, utilizing the heat of fusion in inorganic molten salt mixtures in addition to sensible heat , as in a Phase change material (PCM)-based TES, can significantly increase the energy density of storage requiring less salt and smaller containers. A major issue that is preventing the commercial use of PCM-based TES is that it is difficult to discharge the latent heat stored in the PCM melt. This is because when heat is extracted, the melt solidifies onto the heat exchanger surface decreasing the heat transfer. Even a few millimeters of thickness of solid material on heat transfer surface results in a large drop in heat transfer due to the low thermal conductivity of solid PCM. Thus, to maintain the desired heat rate, the heat exchange area must be large which increases cost. This project demonstrated that the heat transfer coefficient can be increase ten-fold by using forced convection by pumping a hyper-eutectic salt mixture over specially coated heat exchanger tubes. However,only 15% of the latent heat is used against a goal of 40% resulting in a projected cost savings of only 17% against a goal of 30%. Based on the failure mode effect analysis and experience with pumping salt at near freezing point significant care must be used during operation which can increase the operating costs. Therefore, we conclude the savings are marginal to justify using this concept for PCM-TES over a two-tank TES. The report documents the specialty coatings, the composition and morphology of hypereutectic salt mixtures and the results from the experiment conducted with the active heat exchanger along with the lessons learnt during experimentation.

  13. Study of thermal energy storage using fluidized bed heat exchangers

    NASA Technical Reports Server (NTRS)

    Weast, T. E.; Shannon, L. J.; Ananth, K. P.

    1980-01-01

    The technical and economic feasibility of fluid bed heat exchangers (FBHX) for thermal energy storage (TES) in waste heat recovery applications is assessed by analysis of two selected conceptual systems, the rotary cement kiln and the electric arc furnace. It is shown that the inclusion of TES in the energy recovery system requires that the difference in off-peak and on-peak energy rates be large enough so that the value of the recovered energy exceeds the value of the stored energy by a wide enough margin to offset parasitic power and thermal losses. Escalation of on-peak energy rates due to fuel shortages could make the FBHX/TES applications economically attractive in the future.

  14. Thermal Assessment of a Latent-Heat Energy Storage Module During Melting and Freezing for Solar Energy Applications

    NASA Astrophysics Data System (ADS)

    Ramos Archibold, Antonio

    Capital investment reduction, exergetic efficiency improvement and material compatibility issues have been identified as the primary techno-economic challenges associated, with the near-term development and deployment of thermal energy storage (TES) in commercial-scale concentrating solar power plants. Three TES techniques have gained attention in the solar energy research community as possible candidates to reduce the cost of solar-generated electricity, namely (1) sensible heat storage, (2) latent heat (tank filled with phase change materials (PCMs) or encapsulated PCMs packed in a vessel) and (3) thermochemical storage. Among these the PCM macro-encapsulation approach seems to be one of the most-promising methods because of its potential to develop more effective energy exchange, reduce the cost associated with the tank and increase the exergetic efficiency. However, the technological barriers to this approach arise from the encapsulation techniques used to create a durable capsule, as well as an assessment of the fundamental thermal energy transport mechanisms during the phase change. A comprehensive study of the energy exchange interactions and induced fluid flow during melting and solidification of a confined storage medium is reported in this investigation from a theoretical perspective. Emphasis has been placed on the thermal characterization of a single constituent storage module rather than an entire storage system, in order to, precisely capture the energy exchange contributions of all the fundamental heat transfer mechanisms during the phase change processes. Two-dimensional, axisymmetric, transient equations for mass, momentum and energy conservation have been solved numerically by the finite volume scheme. Initially, the interaction between conduction and natural convection energy transport modes, in the absence of thermal radiation, is investigated for solar power applications at temperatures (300--400°C). Later, participating thermal radiation within the storage medium has been included in order to extend the conventional natural convection-dominated model and to analyze its influence on the melting and freezing dynamics at elevated temperatures (800-850°C). A parametric analysis has been performed in order to ascertain the effects of the controlling parameters on the melting/freezing rates and the total and radiative heat transfer rates at the inner surface of the shell. The results show that the presence of thermal radiation enhances the melting and solidification processes. Finally, a simplified model of the packed bed heat exchanger with multiple spherical capsules filled with the storage medium and positioned in a vertical array inside a cylindrical container is analyzed and numerically solved. The influence of the inlet mass flow rate, inner shell surface emissivity and PCM attenuation coefficient on the melting dynamics of the PCM has been analyzed and quantified.

  15. Enhanced Solar Assisted Building Ventilation System Using Sphere Encapsulated PCM Thermal Heat Storage

    Microsoft Academic Search

    C. ARKAR; S. MEDVED

    In the article we are presenting the design of latent heat storage with small polyethylene spheres with encapsulated PCM, which forms porous media inside the duct of the building ventilation system. In this study we assumed that ambient air is first heated in solar roof, than passes trough latent heat storage and at the end enters into living spaces as

  16. Latent heat storage technology and application workshop. Summary report: Session 6

    NASA Astrophysics Data System (ADS)

    Martin, J. F.

    Latent heat storage technology and application were studied. The economics of short term latent heat storage for application and system configuration were analyzed. Subjects discussed included: state of the art, solar energy stores, residential heating and cooling, and industrial and utility applications.

  17. Transient-heat-transfer and stress analysis of a thermal-storage solar cooker module

    E-print Network

    Zengeni, Hazel C

    2014-01-01

    This paper details the analysis carried out in Solidworks to determine the best material and configuration of a thermal-storage solar cooker module.The thermal-storage solar cooker utilizes the high-latent-heat lithium ...

  18. Radiative heat transfer in a planar medium with anisotropic scattering and directional boundaries

    Microsoft Academic Search

    R. O. Buckius; M. M. Tseng

    1978-01-01

    Radiation heat transfer in an absorbing, emitting, and scattering medium has been the subject of many previous investigations. Most solutions are numerically complex, and the existing analytical solutions are restricted in application by the simplifying assumptions involved. A plane-parallel medium is considered which scatters anisotropically. The boundaries are considered to be specular reflectors, as predicted by Fresnel's relations, while the

  19. Thermal energy storage systems using fluidized bed heat exchangers

    SciTech Connect

    Weast, T.; Shannon, L.

    1980-06-01

    The purpose of this study was to conduct a technical and economical assessment of the use of fluid bed heat exchangers (FBHX) for Thermal Energy Storage (TES) in applications having potential for waste heat recovery. A large number of industrial processes and solar power generation were considered to determine the applicability of a FBHX for TES. The potential applications were grouped on a unit operations basis so that if the system was applicable to one industry it may also be adaptable to other industries having similar unit operations. The rotary cement kiln and the electric arc furnace were chosen for evaluation using a variety of screening criteria. Numerous potential FBHX configurations were evaluated to identify the most effective types for TES systems and ranked according to operating parameters such as efficiency of heat recovery, heat transfer rate, system pressure drop, environmental problems, stability of bed operation, etc. In order to maximize the system's effectiveness while minimizing parasitic power requirements, multistage shallow bed FBHX's operating with high temperature differences were identified as the most suitable for TES applications. The technical feasibility of FBHX for TES systems has been verified by analysis of the two selected conceptual systems. Each technical evaluation included establishing a plant process flow configuration, an operational scenario, a preliminary FBHX/TES design, and parametric analysis. A computer model was developed to determine the effects of the number of stages, gas temperatures, gas flows, bed materials, charge and discharge times, and parasitic power required for operation.

  20. Experimental determination of soil heat storage for the simulation of heat transport in a coastal wetland

    NASA Astrophysics Data System (ADS)

    Swain, Michael; Swain, Matthew; Lohmann, Melinda; Swain, Eric

    2012-02-01

    SummaryTwo physical experiments were developed to better define the thermal interaction of wetland water and the underlying soil layer. This information is important to numerical models of flow and heat transport that have been developed to support biological studies in the South Florida coastal wetland areas. The experimental apparatus consists of two 1.32 m diameter by 0.99 m tall, trailer-mounted, well-insulated tanks filled with soil and water. A peat-sand-soil mixture was used to represent the wetland soil, and artificial plants were used as a surrogate for emergent wetland vegetation based on size and density observed in the field. The tanks are instrumented with thermocouples to measure vertical and horizontal temperature variations and were placed in an outdoor environment subject to solar radiation, wind, and other factors affecting the heat transfer. Instruments also measure solar radiation, relative humidity, and wind speed. Tests indicate that heat transfer through the sides and bottoms of the tanks is negligible, so the experiments represent vertical heat transfer effects only. The temperature fluctuations measured in the vertical profile through the soil and water are used to calibrate a one-dimensional heat-transport model. The model was used to calculate the thermal conductivity of the soil. Additionally, the model was used to calculate the total heat stored in the soil. This information was then used in a lumped parameter model to calculate an effective depth of soil which provides the appropriate heat storage to be combined with the heat storage in the water column. An effective depth, in the model, of 5.1 cm of wetland soil represents the heat storage needed to match the data taken in the tank containing 55.9 cm of peat/sand/soil mix. The artificial low-density laboratory sawgrass reduced the solar energy absorbed by the 35.6 cm of water and 55.9 cm of soil at midday by less than 5%. The maximum heat transfer into the underlying peat-sand-soil mix lags behind maximum solar radiation by approximately 2 h. A slightly longer temperature lag was observed between the maximum solar radiation and maximum water temperature both with and without soil.

  1. Modeling the Performance of a Solar Heated Sunroom: Heat Gain, Storage and Loss

    NSDL National Science Digital Library

    John E. Petersen

    In this module students build, explore and modify dynamic simulation models of solar gain, heat storage, transfer and loss in a sunroom. The objective of this module is to provide students with a practical example of how basic mathematical formulations and a variety of simplifying assumptions can be combined to develop a model that can be used to improve system design, analyze system performance, and explore the efficacy of different management approaches for optimizing thermal performance.

  2. Hydrogen storage system based on novel carbon materials and heat pipe heat exchanger

    Microsoft Academic Search

    L. L. Vasiliev; L. E. Kanonchik; A. G. Kulakov; V. A. Babenko

    2007-01-01

    Adsorbed hydrogen is being considered as a potential energy carrier for vehicular applications to replace compressed gas due to its high energy density capability. A new design of hydrogen storage vessel using novel carbon sorbents and heat pipes thermal control is the subject of research program oriented on 5–10 kg of hydrogen be stored on-board. Porous structure and hydrogen-sorption capacities

  3. Exergetic Evaluation of an Organic Rankine Cycle Using Medium-Grade Waste Heat

    Microsoft Academic Search

    P. J. Mago

    2012-01-01

    This article presents an exergetic analysis for an organic Rankine cycle that converts waste energy to power from medium-grade heat sources (503 to 923 K). In addition, the effect of the waste heat temperature, the evaporator pressure, and the pinch point temperature difference on the thermal and exergetic performance of the system is studied. Several organic working fluids were selected

  4. An appraisal of one-dimensional analytical models for the packed bed thermal storage systems utilizing sensible heat storage materials

    Microsoft Academic Search

    G. A. Adebiyi; D. J. Chenevert

    1996-01-01

    This article gives an appraisal of existing analytical one-dimensional models for the packed bed thermal energy storage (TES) systems utilizing sensible heat storage (SHS) materials. The models include that of Schumann, which is for separate phases, but does not include axial conductivity (or dispersion) in the bed, nd the single-phase model of Riaz which includes axial dispersion. An alternative axial

  5. Castor-1C spent fuel storage cask decay heat, heat transfer, and shielding analyses

    SciTech Connect

    Rector, D.R.; McCann, R.A.; Jenquin, U.P.; Heeb, C.M.; Creer, J.M.; Wheeler, C.L.

    1986-12-01

    This report documents the decay heat, heat transfer, and shielding analyses of the Gesellschaft fuer Nuklear Services (GNS) CASTOR-1C cask used in a spent fuel storage demonstration performed at Preussen Elektra's Wurgassen nuclear power plant. The demonstration was performed between March 1982 and January 1984, and resulted in cask and fuel temperature data and cask exterior surface gamma-ray and neutron radiation dose rate measurements. The purpose of the analyses reported here was to evaluate decay heat, heat transfer, and shielding computer codes. The analyses consisted of (1) performing pre-look predictions (predictions performed before the analysts were provided the test data), (2) comparing ORIGEN2 (decay heat), COBRA-SFS and HYDRA (heat transfer), and QAD and DOT (shielding) results to data, and (3) performing post-test analyses if appropriate. Even though two heat transfer codes were used to predict CASTOR-1C cask test data, no attempt was made to compare the two codes. The codes are being evaluated with other test data (single-assembly data and other cask data), and to compare the codes based on one set of data may be premature and lead to erroneous conclusions.

  6. Heat recovery and thermal storage : a study of the Massachusetts State Transportation Building

    E-print Network

    Bjorklund, Abbe Ellen

    1986-01-01

    A study of the energy system at the Massachusetts State Transportation Building was conducted. This innovative energy system utilizes internal-source heat pumps and a water thermal storage system to provide building heating ...

  7. Thermal Energy Storage/Heat Recovery and Energy Conservation in Food Processing

    E-print Network

    Combes, R. S.; Boykin, W. B.

    1980-01-01

    from waste heat streams for reuse in the processing operations. This paper addresses the recovery of waste heat and the storage of thermal energy as a means of energy conservation in food processing. An energy conservation project in a poultry...

  8. An analytical study of heat exchanger effectiveness and thermal performance in a solar energy storage system with PCM

    Microsoft Academic Search

    J. C. Y. Wang; C. C. K. Kwok; S. Lin; G. H. Vatistas

    1984-01-01

    Solar thermal energy storage systems can be categorized based on materials that store either as sensible heat or as latent heat of fusion. For convenience, the latter are designated as phase change materials (PCM). It is a fairly well accepted fact that PCM storage devices usually require less storage volume. In a recent paper, heat exchanger effectiveness for PCM storage

  9. Delayed replantation of rat teeth after use of reconstituted powdered milk as a storage medium.

    PubMed

    dos Santos, Cláudia Letícia Vendrame; Sonoda, Celso Koogi; Poi, Wilson Roberto; Panzarini, Sônia Regina; Sundefeld, Maria Lúcia Marçal Mazza; Negri, Márcia Regina

    2009-02-01

    Minimal extraoral dry storage period and moist storage for the avulsed tooth are identified as key steps for the treatment protocol of tooth replantation. Among the possible moist storage media, bovine milk has stood out because of its capacity of preserving the integrity of the periodontal ligament (PDL) fibers. This condition has attracted the attention to investigate the use of powdered milk, which is one of the presentation forms of bovine milk, as a feasible storage medium in cases of delayed tooth replantation. The aim of this study was to evaluate the healing process after delayed replantation of rat teeth stored in reconstituted powdered milk and long shelf-life (ultra high temperature) whole milk. Forty maxillary right rat incisors were assigned to four groups (n = 10): group I--the teeth were extracted and immediately replanted into theirs sockets; group II--the teeth were stored for 60 min in 200 ml of freshly reconstituted powdered milk; group III--the teeth were stored for 60 min in 200 ml of long shelf-life whole milk; group IV--the teeth were kept dry for the same time. All procedures were performed at room temperature. Next, the root canals of teeth in groups II, III, and IV were instrumented, filled with a calcium hydroxide-based paste, and replanted into their sockets. All animals received systemic antibiotic therapy and were killed by anesthetic overdose 60 days after replantation. The pieces containing the replanted teeth were removed, fixed, decalcified, and paraffin-embedded. Semi-serial 6-microm-thick sections were obtained and stained with hematoxylin and eosin for histomorphological analysis. There was statistically significant difference (P < 0.05) between groups I and IV regarding the presence of replacement resorption and PDL remnants on root surface. The powdered milk and long shelf-life whole milk presented similar results to each other and may be indicated as storage media for avulsed teeth. PMID:19208010

  10. Heating the Intracluster Medium: Magnetohydrodynamic (MHD) Simulations of Shock/Bubble Rotational Heating

    NASA Astrophysics Data System (ADS)

    Friedman, Samuel H.; Heinz, S.

    2010-01-01

    Recent observations of galaxy clusters show that temperatures of the intracluster medium (ICM) lie in the range of 10-100 million K. We would expect this gas to cool via radiative cooling; however, we do not observe this cooling. One way of keeping the ICM hot involves the coupling of jets emanating from supermassive black holes at the centers of galaxies within the cluster with the ICM. The energies involved in the bubbles that these jets inflate in the ICM can provide sufficient energy to heat the gas. However, we do not know how the jet energy becomes thermalized; we present a mechanism that will thermalize the jet energy. The jets have a duty cycle which can cause a shock wave to run across a previously inflated underdense bubble in the ICM. The resulting instability (Richtmyer-Meshkov) causes energy from the shock/jet to transform into rotational kinetic energy, which can then thermalize through turbulence and viscosity. We present the results of shock/bubble interactions with 2D and 3D hydrodynamic and magnetohydrodynamic (MHD) simulations.

  11. How should body heat storage be determined in humans: by thermometry or calorimetry?

    Microsoft Academic Search

    André L. Vallerand; Gustave Savourey; Anne-Marie Hanniquet; Jacques H. M. Bittel

    1992-01-01

    Summary  The aim of this study was to determine whether in humans there are differences in the heat storage calculated by partitional calorimetry (S, the balance of heat gains and heat losses) compared to the heat storage obtained by conventional methods (thermometry) via either core temperature or mean body temperatures (\\u000a$$\\\\bar T_b = 0.8T_c + 0.2\\\\bar T_{sk} $$\\u000a, whereT

  12. Metal-halide mixtures for latent heat energy storage

    NASA Technical Reports Server (NTRS)

    Chen, K.; Manvi, R.

    1981-01-01

    Alkali metal and alkali halide mixtures are identified which may be suitable for thermal energy storage at temperatures above 600 C. The use of metal-halides is appropriate because of their tendency to form two immiscible melts with a density difference, which reduces scale formation and solidification on heat transfer surfaces. Also, the accumulation of phase change material along the melt interface is avoided by the self-dispersing characteristic of some metal-halides, in particular Sr-SrCl2, Ba-BaCl2, and Ba-BaBr2 mixtures. Further advantages lie in their high thermal conductivities, ability to cope with thermal shock, corrosion inhibition, and possibly higher energy densities.

  13. Heating of the interstellar medium by the solar wind

    NASA Technical Reports Server (NTRS)

    Kunc, J. A.; Wu, F. M.; Judge, D. L.

    1983-01-01

    The heating of inflowing interstellar gas by the solar wind is calculated. The experimental differential cross sections have been used for calculating electron-H(He) and proton-H(He) elastic scattering rate coefficients. The solar wind is assumed to be a two-component (protons and electrons), steady, spherically symmetric stream moving radially outward, with the inflowing gas following Keplerian trajectories. The spatial distributions of effective temperature increase within interplanetary space have been obtained.

  14. Model of a thermal energy storage device integrated into a solar assisted heat pump system for space heating

    Microsoft Academic Search

    Viorel Badescu

    2003-01-01

    Details about modelling a sensible heat thermal energy storage (TES) device integrated into a space heating system are given. The two main operating modes are described. Solar air heaters provide thermal energy for driving a vapor compression heat pump. The TES unit ensures a more efficient usage of the collected solar energy. The TES operation is modeled by using two

  15. A review of materials, heat transfer and phase change problem formulation for latent heat thermal energy storage systems (LHTESS)

    Microsoft Academic Search

    Francis Agyenim; Neil Hewitt; Philip Eames; Mervyn Smyth

    2010-01-01

    This paper reviews the development of latent heat thermal energy storage systems studied detailing various phase change materials (PCMs) investigated over the last three decades, the heat transfer and enhancement techniques employed in PCMs to effectively charge and discharge latent heat energy and the formulation of the phase change problem. It also examines the geometry and configurations of PCM containers

  16. Thermal response in thermal energy storage material around heat transfer tubes: effect of additives on heat transfer rates

    Microsoft Academic Search

    Yuichi Hamada; Wataru Ohtsu; Jun Fukai

    2003-01-01

    The effects of carbon-fiber chips and carbon brushes as additives on the thermal conductivity enhancement of phase change materials (PCMs) using in latent heat thermal energy storage are investigated experimentally and numerically by considering the wall effect of the additives. The carbon-fiber chips are effective for improving the heat transfer rate in PCMs. However, the thermal resistance near the heat

  17. Thermal Performance of a Solar Heat Storage Accumulator Used For Greenhouses Conditioning

    Microsoft Academic Search

    Mejdi Hazami; Sami Kooli; Meriam Lazaar; Abdelhamid Farhat; Ali Belghith

    2005-01-01

    The use of solar energy for greenhouse heating has gained an increasing acceptance during the last years. Active solar systems applied to greenhouses can supply a significant part of the heating requirements. However, there are some problems related to the cost of the heat collection unit and the heat storage methods. In this context several techniques were born. The most

  18. Storage of thermal energy by solid-liquid phase change - Temperature drop and heat flux

    Microsoft Academic Search

    N. Shamsundar; E. M. Sparrow

    1974-01-01

    A circular tube filled with a phase change material (pcm) and situated in a fluid environment is analyzed. During energy storage, heat flows from the environment into the pcm, causing the pcm to melt. In heat extraction, heat flows from the pcm into the environment and the pcm solidifies. Results are found for two cases: heat extraction as a uniform

  19. Evaluation of ground-source heat pump combined latent heat storage system performance in greenhouse heating

    Microsoft Academic Search

    Hüseyin Benli; Ayd?n Durmu?

    2009-01-01

    The use of renewable energy for greenhouse heating in winter and cold days, helps to save fossil fuels and conserve green farm environment on the one hand, and on the other hand, enhances the quality of agricultural products, reduces production costs and limits the release of greenhouse gases. In this study, a ground-source heat pump-phase change material (GSHP-PCM) latent heat

  20. Heat transfer characteristics of thermal energy storage system using PCM capsules: A review

    Microsoft Academic Search

    A. Felix Regin; S. C. Solanki; J. S. Saini

    2008-01-01

    Thermal energy storage has recently attracted increasing interest related to thermal applications such as space and water heating, waste heat utilization, cooling and air-conditioning. Energy storage is essential whenever there is a mismatch between the supply and consumption of energy. Use of phase change material (PCM) capsules assembled as a packed bed is one of the important methods that has

  1. A Novel Integrated Frozen Soil Thermal Energy Storage and Ground-Source Heat Pump System

    E-print Network

    Jiang, Y.; Yao, Y.; Rong, L.; Ma, Z.

    2006-01-01

    In this paper, a novel integrated frozen soil thermal energy storage and ground-source heat pump (IFSTS&GSHP) system in which the GHE can act as both cold thermal energy storage device and heat exchanger for GSHP is first presented. The IFSTS...

  2. Heat transfer from cylinders during melting of a thermal energy storage material

    Microsoft Academic Search

    A. G. Bathelt; R. Viskanta; W. Leidenfrost

    1978-01-01

    Melting from an electrically heated single cylinder and an array of three cylinders imbedded in a phase change material (PCM) during the charging cycle of a thermal energy storage (TES) system was studied experimentally. A paraffin (n-octadecane) having a melting temperature of 301 K was used as storage material. A shadowgraph technique was employed to optically determine the local heat

  3. Response of wall heat transfer to flows along a cylindrical cavity and to seepage flows in the surrounding medium

    E-print Network

    Eindhoven, Technische Universiteit

    of software used to simulate complex fluid/heat flows. KEY WORDS forced convection, porous medium, radial, there may be both heat and mass exchange between the cavity and the medium, whereas in others, there may be only heat exchange. The latter is the case, for inst

  4. Magnesium fluoride as energy storage medium for spacecraft solar thermal power systems

    NASA Technical Reports Server (NTRS)

    Lurio, Charles A.

    1992-01-01

    MgF2 was investigated as a phase-change energy-storage material for LEO power systems using solar heat to run thermal cycles. It provides a high heat of fusion per unit mass at a high melting point (1536 K). Theoretical evaluation showed the basic chemical compatibility of liquid MgF2 with refractory metals at 1600 K, though transient high pressures of H2 can occur in a closed container due to reaction with residual moisture. The compatibility was tested in two refractory metal containers for over 2000 h. Some showed no deterioration, while there was evidence that the fluoride reacted with hafnium in others. Corollary tests showed that the MgF2 supercooled by 10-30 K and 50-90 K.

  5. Design and development of integral heat pipe/thermal energy storage devices. [used with spacecraft cryocoolers

    NASA Technical Reports Server (NTRS)

    Mahefkey, E. T.; Richter, R.

    1981-01-01

    The major design and performance test subtasks in the development of small (200 to 1,000 whr) integral heat pipe/thermal energy storage devices for use with thermally driven spacecraft cryo-coolers are described. The design of the integral heat pipe/thermal energy storage device was based on a quasi steady resistance heat transfer, lumped capacitance model. Design considerations for the heat pipe and thermal storage annuli are presented. The thermomechanical stress and insulation system design for the device are reviewed. Experimental correlations are described, as are the plans for the further development of the concept.

  6. [Use of hydroxyethyl starch as a cryoprotective medium during platelet storage at low temperatures].

    PubMed

    Kotelba-Witkowska, B; Gryszkiewicz, A

    1975-01-01

    The effects of HES and HES + DMSO used as cryoprotective media for storage of human platelets in liquid nitrogen and vapor phase of liquid nitrogen were studied. Solution of 6% and 15% HES with molecular weight ranging from 65,000 to 250,000, and 10% DMSO were used. The criteria accepted for evaluation of the efficiency of these cryoprotective media were: 1. platelet counts, 2. participation of platelets in the processes of hemostasis measured in vitro by the ability of platelets to release adenine nucleotides (ATP + ADP) after thrombin stimulation. It was found that 15% HES is a more effective cryoprotective medium than 6% HES. The use of 15% HES + 10% DMSO gave similar results as the use of 10% DMSO alone. PMID:53981

  7. Effect of pH heating medium on the thermal resistance of Bacillus stearothermophilus spores

    Microsoft Academic Search

    M. López; I. González; S. Condón; A. Bernardo

    1996-01-01

    The influence of the pH of heating medium on heat resistance of Bacillus stearothermophilus spores (ATCC 7953, 12980, 15951 and 15952) were studied. The pH values tested were: 4.0, 5.0, 6.0 and 7.0 at temperatures of 115, 120, 125, 130 and 135 °C. It was found that at low treatment temperatures (115 °C) D-values decreased between 7- and 10-fold with

  8. Waste heat recovery from heavy-duty diesel engine exhaust gases by medium temperature ORC system

    Microsoft Academic Search

    MingShan Wei; JinLi Fang; ChaoChen Ma; Syed Noman Danish

    A medium-temperature waste-heat recovery system based on the organic Rankine cycle (ORC) is designed to recover the exhaust\\u000a energy from a heavy-duty diesel engine. Analysis of the 1st law of thermodynamics for an ORC system is performed. This analysis\\u000a contains two parts. The first part is an analysis with undefined heat exchangers to gain an understanding of the ORC and

  9. Thermal energy storage heat exchanger: Molten salt heat exchanger design for utility power plants

    NASA Technical Reports Server (NTRS)

    Ferarra, A.; Yenetchi, G.; Haslett, R.; Kosson, R.

    1977-01-01

    The use of thermal energy storage (TES) in the latent heat of molten salts as a means of conserving fossil fuels and lowering the cost of electric power was evaluated. Public utility systems provided electric power on demand. This demand is generally maximum during late weekday afternoons, with considerably lower overnight and weekend loads. Typically, the average demand is only 60% to 80% of peak load. As peak load increases, the present practice is to purchase power from other grid facilities or to bring older less efficient fossil-fuel plants on line which increase the cost of electric power. The widespread use of oil-fired boilers, gas turbine and diesel equipment to meet peaking loads depletes our oil-based energy resources. Heat exchangers utilizing molten salts can be used to level the energy consumption curve. The study begins with a demand analysis and the consideration of several existing modern fossil-fuel and nuclear power plants for use as models. Salts are evaluated for thermodynamic, economic, corrosive, and safety characteristics. Heat exchanger concepts are explored and heat exchanger designs are conceived. Finally, the economics of TES conversions in existing plants and new construction is analyzed. The study concluded that TES is feasible in electric power generation. Substantial data are presented for TES design, and reference material for further investigation of techniques is included.

  10. Active heat exchange system development for latent heat thermal energy storage

    NASA Technical Reports Server (NTRS)

    Alario, J.; Kosson, R.; Haslett, R.

    1980-01-01

    Various active heat exchange concepts were identified from among three generic categories: scrapers, agitators/vibrators and slurries. The more practical ones were given a more detailed technical evaluation and an economic comparison with a passive tube-shell design for a reference application (300 MW sub t storage for 6 hours). Two concepts were selected for hardware development: (1) a direct contact heat exchanger in which molten salt droplets are injected into a cooler counterflowing stream of liquid metal carrier fluid, and (2) a rotating drum scraper in which molten salt is sprayed onto the circumference of a rotating drum, which contains the fluid salt is sprayed onto the circumference of a rotating drum, which contains the fluid heat sink in an internal annulus near the surface. A fixed scraper blade removes the solidified salt from the surface which was nickel plated to decrease adhesion forces. In addition to improving performance by providing a nearly constant transfer rate during discharge, these active heat exchanger concepts were estimated to cost at least 25% less than the passive tube-shell design.

  11. Thermal energy storage systems using fluidized bed heat exchangers

    NASA Astrophysics Data System (ADS)

    Weast, T.; Shannon, L.

    1980-06-01

    A rotary cement kiln and an electric arc furnace were chosen for evaluation to determine the applicability of a fluid bed heat exchanger (FBHX) for thermal energy storage (TES). Multistage shallow bed FBHX's operating with high temperature differences were identified as the most suitable for TES applications. Analysis of the two selected conceptual systems included establishing a plant process flow configuration, an operational scenario, a preliminary FBHX/TES design, and parametric analysis. A computer model was developed to determine the effects of the number of stages, gas temperatures, gas flows, bed materials, charge and discharge time, and parasitic power required for operation. The maximum national energy conservation potential of the cement plant application with TES is 15.4 million barrels of oil or 3.9 million tons of coal per year. For the electric arc furnance application the maximum national conservation potential with TES is 4.5 million barrels of oil or 1.1 million tons of coal per year. Present time of day utility rates are near the breakeven point required for the TES system. Escalation of on-peak energy due to critical fuel shortages could make the FBHX/TES applications economically attractive in the future.

  12. Heat pump water heater and storage tank assembly

    DOEpatents

    Dieckmann, John T. (Belmont, MA); Nowicki, Brian J. (Watertown, MA); Teagan, W. Peter (Acton, MA); Zogg, Robert (Belmont, MA)

    1999-09-07

    A water heater and storage tank assembly comprises a housing defining a chamber, an inlet for admitting cold water to the chamber, and an outlet for permitting flow of hot water from the chamber. A compressor is mounted on the housing and is removed from the chamber. A condenser comprises a tube adapted to receive refrigerant from the compressor, and winding around the chamber to impart heat to water in the chamber. An evaporator is mounted on the housing and removed from the chamber, the evaporator being adapted to receive refrigerant from the condenser and to discharge refrigerant to conduits in communication with the compressor. An electric resistance element extends into the chamber, and a thermostat is disposed in the chamber and is operative to sense water temperature and to actuate the resistance element upon the water temperature dropping to a selected level. The assembly includes a first connection at an external end of the inlet, a second connection at an external end of the outlet, and a third connection for connecting the resistance element, compressor and evaporator to an electrical power source.

  13. Thermal energy storage systems using fluidized bed heat exchangers

    NASA Technical Reports Server (NTRS)

    Weast, T.; Shannon, L.

    1980-01-01

    A rotary cement kiln and an electric arc furnace were chosen for evaluation to determine the applicability of a fluid bed heat exchanger (FBHX) for thermal energy storage (TES). Multistage shallow bed FBHX's operating with high temperature differences were identified as the most suitable for TES applications. Analysis of the two selected conceptual systems included establishing a plant process flow configuration, an operational scenario, a preliminary FBHX/TES design, and parametric analysis. A computer model was developed to determine the effects of the number of stages, gas temperatures, gas flows, bed materials, charge and discharge time, and parasitic power required for operation. The maximum national energy conservation potential of the cement plant application with TES is 15.4 million barrels of oil or 3.9 million tons of coal per year. For the electric arc furnance application the maximum national conservation potential with TES is 4.5 million barrels of oil or 1.1 million tons of coal per year. Present time of day utility rates are near the breakeven point required for the TES system. Escalation of on-peak energy due to critical fuel shortages could make the FBHX/TES applications economically attractive in the future.

  14. New applications of energy storage in electric heating and cooling systems

    NASA Astrophysics Data System (ADS)

    Asbury, J. G.

    1980-06-01

    Electricity, in combination with appropriate load management techniques, is a cost effective method of providing building heating and cooling services. Storage systems that enable the use of nighttime, off peak, energy to meet the following day's load are among the most promising load management techniques. Studies evaluated the total cost of providing space heating and cooling services with electricity and then compared these costs with oil and gas based systems. Detailed cost allocation models were used to compute gas and electric utility costs of supply. A number of different electric technologies were evaluated including electric storage heating, storage air conditioning, dual fuel heating, and solar heating with electric backup. An important finding is that several electric based heating technologies are cost competitive with oil and natural gas heating.

  15. The exchange of heat between a liquid spheroid and the ambient medium in the presence of Leidenfrost phenomenon

    NASA Astrophysics Data System (ADS)

    Bityukov, V. K.; Kolodezhnov, V. N.

    1989-02-01

    A two-dimensional problem in the hydrodynamics of a vapor layer and the process of heat transfer under conditions of the Leidenfrost phenomenon is examined in the exchange of heat between a liquid spheroid and the ambient medium.

  16. The morphology of cavitation damage of heat-treated medium carbon steel

    Microsoft Academic Search

    MARINA DOJ

    In this paper the morphology of the cavitation damage to heat-treated medium carbon steel was analyzed. The experiments were conducted using a modified vibratory cavitation test set up. The erosion rates were measured by an analytical method. The mor- phology of the cavitation damage was studied by the scanning electron microscopy and optical microscopy techniques. The present work was aimed

  17. Numerical simulation of soil heat exchanger-storage systems for greenhouses

    Microsoft Academic Search

    Carol Gauthier; Marcel Lacroix; Hervé Bernier

    1997-01-01

    A numerical study was conducted for the thermal behavior of soil heat exchanger-storage systems (SHESSs) aimed at reducing the energy consumption of greenhouses. These systems consists of buried pipes circulating air for storing and removing heat from the soil. First, a transient fully three-dimensional heat transfer model resting on the coupled conservation equations of energy for the soil and the

  18. Analysis and design of the ''Solar One'' thermal storage subsystem heat exchangers

    Microsoft Academic Search

    F. R. Weiner

    1984-01-01

    This paper describes the analysis and design of the five kinds of heat exchangers used in the thermal storage subsystem of the 10 MWe Solar Central Receiver Pilot Plant, now becoming more known as ''Solar One''. The paper discusses the practices and standards used in the designs of the heat exchangers, lists the heat exchanger design requirements, and discusses the

  19. Analysis and design of the 'Solar One' thermal storage subsystem heat exchangers

    Microsoft Academic Search

    F. R. Weiner

    1984-01-01

    This paper describes the analysis and design of the five kinds of heat exchangers used in the thermal storage subsystem of the 10 MWe Solar Central Receiver Pilot Plant, now becoming more known as 'Solar One'. The paper discusses the practices and standards used in the designs of the heat exchangers, lists the heat exchanger design requirements, and discusses the

  20. Analysis of solar aided heat pump systems with seasonal thermal energy storage in surface tanks

    Microsoft Academic Search

    R. Yumruta?; M. Ünsal

    2000-01-01

    Annual periodic performance of a solar assisted ground-coupled heat pump space heating system with seasonal energy storage in a hemispherical surface tank is investigated using analytical and computational methods. The system investigated employs solar energy collection and dumping into a seasonal surface tank throughout the whole year with extraction of thermal energy from the tank for space heating during the

  1. Latent heat thermal energy storage using cylindrical capsule: Numerical and experimental investigations

    Microsoft Academic Search

    A. Felix Regin; S. C. Solanki; J. S. Saini

    2006-01-01

    This paper is aimed at analyzing the melting behavior of paraffin wax as a phase change material (PCM) encapsulated in a cylindrical capsule, used in a latent heat thermal energy storage system with a solar water heating collector. The heat for melting of PCM in the capsule is provided by hot water surrounding it. Since it is observed experimentally that

  2. Numerical Simulation of a Latent Heat Storage System of a Solar-Aided Ground Source Heat Pump

    E-print Network

    Wang, F.; Zheng, M.; Li, Z.; Lei, B.

    2006-01-01

    ICEBO2006, Shenzhen, China Re newable Energy Resources and a Greener Future Vol.VIII-2-4 Numerical Simulation of a Latent Heat Storage System of a Solar-Aided Ground Source Heat Pump Fang Wang Maoyu Zheng Zhongjian Li...

  3. Experimental investigation on performance of ice storage air-conditioning system with separate heat pipe

    SciTech Connect

    Fang, Guiyin; Liu, Xu; Wu, Shuangmao [Department of Physics, Nanjing University, Nanjing 210093 (China)

    2009-11-15

    An experimental study on operation performance of ice storage air-conditioning system with separate helical heat pipe is conducted in this paper. The experimental system of ice storage air-conditioning system with separate heat pipe is set up. The performance parameters such as the evaporation pressure and the condensation pressure of refrigeration system, the refrigeration capacity and the COP (coefficient of performance) of the system, the IPF (ice packing factor) and the cool storage capacity in the cool storage tank during charging period, and the cool discharge rate and the cool discharge capacity in the cool storage tank, the outlet water temperature in the cool storage tank and the outlet air temperature in room unit during discharging period are investigated. The experimental results show that the ice storage air-conditioning system with separate helical heat pipe can stably work during charging and discharging period. This indicates that the ice storage air-conditioning system with separate helical heat pipe is well adapted to cool storage air-conditioning systems in building. (author)

  4. Nonsimilar hydromagnetic simultaneous heat and mass transfer by mixed convection from a vertical plate embedded in a uniform porous medium

    SciTech Connect

    Chamkha, A.J.; Khaled, A.R.A. [Kuwait Univ., Safat (Kuwait). Dept. of Mechanical and Industrial Engineering

    1999-08-27

    Simultaneous heat and mass transfer from different geometries embedded in porous media has many engineering and geophysical applications, such as migration of water in geothermal reservoirs, underground spreading of chemical wastes and other pollutants, thermal insulation, enhanced oil recovery, packed-bed catalytic reactors, cooling of nuclear reactors, grain storage, and evaporative cooling and solidification. This work considers steady, laminar, hydromagnetic simultaneous heat and mass transfer by mixed convection flow over a permeable vertical plate immersed in a uniform porous medium for the cases of power law variations of both the wall temperature and concentration and the wall heat flux and mass flux. Appropriate transformations are employed to transform the governing differential equations to a nonsimilar form. The transformed equations are solved numerically by an accurate, implicit, iterative, finite difference method. The obtained results are validated by favorable comparisons with previously published work on special cases of the problem. A parametric study illustrating the influence of all involved parameters on the local Nusselt and Sherwood numbers is conducted. The results of this parametric study are shown graphically, and the physical aspects of the problem are discussed.

  5. Active heat exchange system development for latent heat thermal energy storage

    NASA Technical Reports Server (NTRS)

    Alario, J.; Haslett, R.

    1980-01-01

    Various active heat exchange concepts were identified from among three generic categories: scrapers, agitators/vibrators and slurries. The more practical ones were given a more detailed technical evaluation and an economic comparison with a passive tube-shell design for a reference application. Two concepts selected for hardware development are a direct contact heat exchanger in which molten salt droplets are injected into a cooler counterflowing stream of liquid metal carrier fluid, and a rotating drum scraper in which molten salt is sprayed onto the circumference of a rotating drum, which contains the fluid heat sink in an internal annulus near the surface. A fixed scraper blade removes the solidified salt from the surface which has been nickel plated to decrease adhesion forces. Suitable phase change material (PCM) storage media with melting points in the temperature range of interest (250 C to 400 C) were investigated. The specific salt recommended for laboratory tests was a chloride eutectic (20.5KCl-24/5 NaCl-55.0MgCl 2% by wt.), with a nominal melting point of 385 C.

  6. Numerical Simulation of a Radiant Heating System Using Solar-Ground Coupled Heat Pump with Seasonal Thermal Storage

    Microsoft Academic Search

    Xiao Wang; Maoyu Zheng; Wenyong Zhang

    2010-01-01

    To apply the solar-ground coupled heat pump (SGCHP) in severe cold areas, this paper presents the simulation study on a radiant heating system using SGCHP with seasonal thermal storage. The radiant heating system was installed in a detached house in the suburbs of Harbin (126°46'E, 45°45'N). The unit model of each component was given. The performance and operation characteristics of

  7. Natural convection heat transfer of nanofluids along a vertical plate embedded in porous medium.

    PubMed

    Uddin, Ziya; Harmand, Souad

    2013-01-01

    The unsteady natural convection heat transfer of nanofluid along a vertical plate embedded in porous medium is investigated. The Darcy-Forchheimer model is used to formulate the problem. Thermal conductivity and viscosity models based on a wide range of experimental data of nanofluids and incorporating the velocity-slip effect of the nanoparticle with respect to the base fluid, i.e., Brownian diffusion is used. The effective thermal conductivity of nanofluid in porous media is calculated using copper powder as porous media. The nonlinear governing equations are solved using an unconditionally stable implicit finite difference scheme. In this study, six different types of nanofluids have been compared with respect to the heat transfer enhancement, and the effects of particle concentration, particle size, temperature of the plate, and porosity of the medium on the heat transfer enhancement and skin friction coefficient have been studied in detail. It is found that heat transfer rate increases with the increase in particle concentration up to an optimal level, but on the further increase in particle concentration, the heat transfer rate decreases. For a particular value of particle concentration, small-sized particles enhance the heat transfer rates. On the other hand, skin friction coefficients always increase with the increase in particle concentration and decrease in nanoparticle size. PMID:23391481

  8. Natural convection heat transfer of nanofluids along a vertical plate embedded in porous medium

    PubMed Central

    2013-01-01

    The unsteady natural convection heat transfer of nanofluid along a vertical plate embedded in porous medium is investigated. The Darcy-Forchheimer model is used to formulate the problem. Thermal conductivity and viscosity models based on a wide range of experimental data of nanofluids and incorporating the velocity-slip effect of the nanoparticle with respect to the base fluid, i.e., Brownian diffusion is used. The effective thermal conductivity of nanofluid in porous media is calculated using copper powder as porous media. The nonlinear governing equations are solved using an unconditionally stable implicit finite difference scheme. In this study, six different types of nanofluids have been compared with respect to the heat transfer enhancement, and the effects of particle concentration, particle size, temperature of the plate, and porosity of the medium on the heat transfer enhancement and skin friction coefficient have been studied in detail. It is found that heat transfer rate increases with the increase in particle concentration up to an optimal level, but on the further increase in particle concentration, the heat transfer rate decreases. For a particular value of particle concentration, small-sized particles enhance the heat transfer rates. On the other hand, skin friction coefficients always increase with the increase in particle concentration and decrease in nanoparticle size. PMID:23391481

  9. Application of heat pipes to thermal energy storage systems

    NASA Astrophysics Data System (ADS)

    Abhat, A.

    1980-07-01

    The application of heat pipes as heat transport elements in a latent heat thermal energy store for solar residential heating systems is proposed. The paper describes the development of a 20 mm diameter, 3070 mm long, axially-grooved, copper-water heat pipe selected for this purpose. The heat pipe was operated with slight gravity assistance and tested in various operational modes that simulated charging, discharging and by-pass of the heat store. Entrainment effects resulted in adverse performance, forcing modifications in the capillary structure. Results from experiments performed during three tests series, characterized by the type of capillary structure used, are discussed.

  10. EVALUATION OF A SULFUR OXIDE CHEMICAL HEAT STORAGE PROCESS FOR A STEAM SOLAR ELECTRIC PLANT

    E-print Network

    Dayan, J.

    2011-01-01

    ix- In the base case the solar tower receives heat at a netIN THE SOLAR RECEIVER-REACTOR . Dry Cooling Tower -v- TABLEsolar storage system designs; almost all proposed designs may be assumed to have the same tower

  11. Solar powered absorption cycle heat pump using phase change materials for energy storage

    NASA Technical Reports Server (NTRS)

    Middleton, R. L.

    1972-01-01

    Solar powered heating and cooling system with possible application to residential homes is described. Operating principles of system are defined and illustration of typical energy storage and exchange system is provided.

  12. NaOH-based high temperature heat-of-fusion thermal energy storage device

    NASA Technical Reports Server (NTRS)

    Cohen, B. M.; Rice, R. E.

    1978-01-01

    A material called Thermkeep, developed as a low-cost method for the storage of thermal energy for solar electric power generating systems is discussed. The storage device consists of an insulated cylinder containing Thermkeep in which coiled tubular heat exchangers are immersed. A one-tenth scale model of the design contains 25 heat-exchanger tubes and 1500 kg of Thermkeep. Its instrumentation includes thermocouples to measure internal Thermkeep temperatures, vessel surface, heated shroud surface, and pressure gauges to indicate heat-exchanger pressure drops. The test-circuit design is presented and experimental results are discussed.

  13. Performance analysis of a latent heat storage system with phase change material for new designed solar collectors in greenhouse heating

    SciTech Connect

    Benli, Hueseyin [Department of Technical and Vocational Education, Firat University, TR-23119, Elazig (Turkey); Durmus, Aydin [Department of Mechanical Engineering, Ondokuz Mayis University, TR-55139, Samsun (Turkey)

    2009-12-15

    The continuous increase in the level of greenhouse gas emissions and the rise in fuel prices are the main driving forces behind the efforts for more effectively utilize various sources of renewable energy. In many parts of the world, direct solar radiation is considered to be one of the most prospective sources of energy. In this study, the thermal performance of a phase change thermal storage unit is analyzed and discussed. The storage unit is a component of ten pieced solar air collectors heating system being developed for space heating of a greenhouse and charging of PCM. CaCl{sub 2}6H{sub 2}O was used as PCM in thermal energy storage with a melting temperature of 29 C. Hot air delivered by ten pieced solar air collector is passed through the PCM to charge the storage unit. The stored heat is utilized to heat ambient air before being admitted to a greenhouse. This study is based on experimental results of the PCM employed to analyze the transient thermal behavior of the storage unit during the charge and discharge periods. The proposed size of collectors integrated PCM provided about 18-23% of total daily thermal energy requirements of the greenhouse for 3-4 h, in comparison with the conventional heating device. (author)

  14. Relations for local radiative heat transfer between rectangular boundaries of an absorbing-emitting medium

    NASA Technical Reports Server (NTRS)

    Siegel, R.

    1993-01-01

    An analytical solution was obtained by Siegel (1991, 1992) for local boundary heat fluxes by a radiating medium at uniform temperature in a 2D rectangular region. It is shown here that, after local fluxes from the medium to the walls have been evaluated, it is very easy to compute local fluxes arriving from the adjacent and opposite walls. This extends the previous analysis and provides convenient relations to include radiation from a black boundary, each side of the rectangle being at a different uniform temperature. The final expressions are helpful in performing spectral calculations that must be made for many spectral bands.

  15. Cold Heat Storage Characteristics of O/W-type Latent Heat Emulsion Including Continuum Phase of Water Treated with a Freezing Point Depression

    NASA Astrophysics Data System (ADS)

    Inaba, Hideo; Morita, Shin-Ichi

    This paper deals with flow and cold heat storage characteristics of the oil (tetradecane, C14H30, freezing point 278.9 K, Latent heat 229 kJ/kg)/water emulsion as a latent heat storage material having a low melting point. The test emulsion includes a water-urea solution as a continuum phase. The freezing point depression of the continuum phase permits enhancement of the heat transfer rate of the emulison, due to the large temperature difference between the latent heat storage material and water-urea solution. The velocity of emulsion flow and the inlet temperature of coolant in a coiled double tube heat exchanger are chosen as the experimental parameters. The pressure drop, the heat transfer coefficient of the emulsion in the coiled tube are measured in the temperture region over solid and liquid phase of the latent heat storage material. The finishing time of the cold heat storage is defined experimentally in the range of sensible and latent heat storage. It is clarified that the flow behavior of the emulsion as a non-Newtonian fluid has an important role in cold heat storage. The useful nondimentional correlation equations for the additional pressure loss coefficient, the heat transfer coefficient and the finishing time of the cold heat storage are derived in terms of Dean number and heat capacity ratio.

  16. Exergy analysis of particle dispersed latent heat thermal storage system for solar water heaters

    Microsoft Academic Search

    S. Jegadheeswaran; S. D. Pohekar

    2010-01-01

    Phase change material (PCM) based latent heat thermal storage (LHTS) systems offer a challenging option to be employed as an effective energy storage and retrieval device if the energy source is intermittent and time dependent. However, the performance of LHTS systems is limited by the poor thermal conductivity of PCMs employed. The addition of high conductivity particles is proposed as

  17. Use of Thermal Energy Storage to Enhance the Recovery and Utilization of Industrial Waste Heat

    E-print Network

    McChesney, H. R.; Bass, R. W.; Landerman, A. M.; Obee, T. N.; Sgamboti, C. T.

    1982-01-01

    USE OF THERMAL ENERGY STORAGE TO ENHANCE THE RECOVERY AND UTILIZATION OF INDUSTRIAL WASTE HEAT H. R. McChesney, R. W. Bass, A. M. Landerman, T. N. Obee and C. T. Sgambati United Technologies Research Center East Hartford, Connecticut... energy management/thermal energy storage technology (TES) systems can be used with commercially avail to avoid the cost of fossil energy while maintain able energy management equipment to enhance the ing the supply of process heat or electricity...

  18. A direct-heating energy-storage receiver for dish-Stirling solar energy systems

    Microsoft Academic Search

    K. O. Lund

    1996-01-01

    Dish-Stirling solar receiver designs are investigated and evaluated for possible use with sensible energy storage in single-phase materials. The designs differ from previous receivers in utilizing axial conduction in the storage material for attenuation of the solar flux transients due to intermittent cloud cover, and in having convective heat removal at the base of the receiver. One-dimensional, time-dependent heat transfer

  19. Effective-medium model of wire metamaterials in the problems of radiative heat transfer

    SciTech Connect

    Mirmoosa, M. S., E-mail: mohammad.mirmoosa@aalto.fi; Nefedov, I. S., E-mail: igor.nefedov@aalto.fi; Simovski, C. R., E-mail: konstantin.simovski@aalto.fi [Department of Radio Science and Engineering, School of Electrical Engineering, Aalto University, P. O. Box 13000, 00076 Aalto (Finland); Rüting, F., E-mail: felix.ruting@uam.es [Departamento de Física Teorica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autonoma de Madrid, E-28049 (Spain)

    2014-06-21

    In the present work, we check the applicability of the effective medium model (EMM) to the problems of radiative heat transfer (RHT) through so-called wire metamaterials (WMMs)—composites comprising parallel arrays of metal nanowires. It is explained why this problem is so important for the development of prospective thermophotovoltaic (TPV) systems. Previous studies of the applicability of EMM for WMMs were targeted by the imaging applications of WMMs. The analogous study referring to the transfer of radiative heat is a separate problem that deserves extended investigations. We show that WMMs with practically realizable design parameters transmit the radiative heat as effectively homogeneous media. Existing EMM is an adequate tool for qualitative prediction of the magnitude of transferred radiative heat and of its effective frequency band.

  20. Energy-Storage Modules for Active Solar Heating and Cooling

    NASA Technical Reports Server (NTRS)

    Parker, J. C.

    1982-01-01

    34 page report describes a melting salt hydrate that stores 12 times as much heat as rocks and other heavy materials. Energy is stored mostly as latent heat; that is, heat that can be stored and recovered without any significant change in temperature. Report also describes development, evaluation and testing of permanently sealed modules containing salt hydrate mixture.

  1. Effect of composite deflocculant on the properties of medium-cement heat-resistant concrete

    Microsoft Academic Search

    I. Pundene; V. Antonovich; R. Stonis

    2009-01-01

    Comparative analysis is provided for the properties of medium-cement concrete based on mullite filler in relation to different\\u000a type of deflocculant. The effect of different deflocculants on concrete structure formation, hydration, rheology, strength\\u000a and heat resistance is discussed. It is proposed that in concrete with a composite deflocculant it is possible to form nano-structures\\u000a as a result of which there

  2. Experimental Investigations of Flow Resistance and Convection Heat Transfer and Prediction of Cold Heat-Storage Characteristics for a PhaseChange Emulsion in a Coiled Circular Tube

    Microsoft Academic Search

    Zhennan Zhao; Yuquan Shi

    2005-01-01

    This paper introduces emulsion phase change cold heat storage and heat transfer material and its applications and reports its related thermal properties by means of tests and calculations. As a comparison, some available cold heat storage techniques and materials with or without phase change are briefly introduced in respect to their benefits and disadvantages. The paper also investigates flow resistance,

  3. Physicochemical studies of porous materials for thermochemical storage of heat

    Microsoft Academic Search

    J. Jänchen; A. Grimm; H. Stach

    The structure (texture) of an silicagel impregnated with MgCl 2 , CaCl 2 and SrCl 2 as well as the adsorption equilibrium of water against those confined salt hydrates and two different samples of zeolite A were investigated. This materials are potential candidates for (seasonal) thermochemical storage applications. Whereas the mesoporous silica based materials show a high storage capacity the

  4. Thermal energy storage in the ground: Comparative analysis of heat transfer modeling using U-tubes and boreholes

    Microsoft Academic Search

    Dwayne S. Breger; James E. Hubbell; Hamid El Hasnaoui; J. Edward Sunderland

    1996-01-01

    Large scale thermal energy storage for solar heating applications can be accomplished in the ground through the installation of an array of vertical heat exchange boreholes or U-tubes. Simulation modeling of the storage subsystem and its integration with the total system is essential for design and performance evaluation. Although U-tube storage design is especially attractive in clay soils and preferable

  5. Transient performance of a stepped solar still withbuilt-in latent heat thermal energy storage

    Microsoft Academic Search

    Abdulhaiy M. Radhwan

    2005-01-01

    The transient performance of a stepped solar still with built-in latent heat thermal energy storage was studied. Thestill was designed for heating and humidification of agriculture greenhouses (GH) in remote areas. The solar still consists of five stepped basins with an inclined glass cover and is insulated on the bottom. The basin was placed on a slab filled with a

  6. Importance of Salinity Measurements in the Heat Storage Estimation from Topex/Poseidon

    NASA Technical Reports Server (NTRS)

    Sato, O.; Polito, P.; Liu, W.

    1999-01-01

    Sea surface height anomaly signals from satellite altimeter data are used to estimate heat storage. Since variability in sea surface height is mostly due to expansion and contraction of the water column it can be correlated with variations in the heat and salt content.

  7. Application of latent heat thermal energy storage in buildings: State-of-the-art and outlook

    Microsoft Academic Search

    Yinping Zhang; Guobing Zhou; Kunping Lin; Qunli Zhang; Hongfa Di

    2007-01-01

    Latent heat thermal energy storage (LHTES) is becoming more and more attractive for space heating and cooling of buildings. The application of LHTES in buildings has the following advantages: (1) the ability to narrow the gap between the peak and off-peak loads of electricity demand; (2) the ability to save operative fees by shifting the electrical consumption from peak periods

  8. Thermal analysis of a helical heat exchanger for ground thermal energy storage in arid zones

    Microsoft Academic Search

    Y. Rabin; E. Korin

    1996-01-01

    A mathematical model for thermal analysis of a helical heat exchanger for long-term thermal energy storage in soil for use in arid zones was developed. The helical heat exchanger was modeled as a series of horizontal rings with a constant pitch distance between them. The model was solved by a finite difference method, using a microcomputer, and validated with experimental

  9. An appraisal of one-dimensional analytical models for the packed bed thermal storage systems utilizing sensible heat storage materials

    SciTech Connect

    Adebiyi, G.A. [Mississippi State Univ., MS (United States). Dept. of Mechanical Engineering; Chenevert, D. [National Aeronautics and Space Administration, Stennis Space Center, MS (United States)

    1996-03-01

    This article gives an appraisal of existing analytical one-dimensional models for the packed bed thermal energy storage (TES) systems utilizing sensible heat storage (SHS) materials. The models include that of Schumann, which is for separate phases, but does not include axial conductivity (or dispersion) in the bed, nd the single-phase model of Riaz which includes axial dispersion. An alternative axial conductivity model is proposed which compares well with the Schumann model when axial dispersion is negligible, but otherwise caters adequately for axial dispersion at the low Peclet number condition.

  10. Passive annual heat storage: improving the design of earth shelters or how to store summer's sunshine to keep your wigwam warm all winter

    Microsoft Academic Search

    Hait

    1983-01-01

    A practical guide to passive annual heat storage is presented. Year-round energy conservation measures are discussed. Without mechanical equipment or commercial power, passive annual heat storage may be used to inexpensively cool a home during the hot summer months. The following topics are discussed: improving the earth shelter, passive annual heat storage, the use of water in passive heat storage,

  11. Finite-element analysis of cyclic heat transfer in a shell-and-tube latent heat energy storage exchanger

    Microsoft Academic Search

    Zhen-Xiang Gong; Arun S. Mujumdar

    1997-01-01

    The physical module of a shell-and-tube latent heat thermal storage exchanger consists of a tube which is surrounded by an external coaxial cylinder made up of a phase-change material (PCM). A heat-transfer fluid flows through the tube to store or extract thermal energy from the PCM. Two alternative operation modes are possible. One option is to introduce hot and cold

  12. Dynamical stability of a thermally stratified intracluster medium with anisotropic momentum and heat transport

    E-print Network

    Kunz, Matthew W

    2011-01-01

    In weakly-collisional plasmas such as the intracluster medium (ICM), heat and momentum transport become anisotropic with respect to the local magnetic field direction. Anisotropic heat conduction causes the slow magnetosonic wave to become buoyantly unstable to the magnetothermal instability (MTI) when the temperature increases in the direction of gravity and to the heat-flux--driven buoyancy instability (HBI) when the temperature decreases in the direction of gravity. The local changes in magnetic field strength that attend these instabilities cause pressure anisotropies that viscously damp motions parallel to the magnetic field. In this paper we employ a linear stability analysis to elucidate the effects of anisotropic viscosity (i.e. Braginskii pressure anisotropy) on the MTI and HBI. By stifling the convergence/divergence of magnetic field lines, pressure anisotropy significantly affects how the ICM interacts with the temperature gradient. Instabilities which depend upon the convergence/divergence of magn...

  13. Natural convection on a vertical plate in a saturated porous medium with internal heat generation

    NASA Astrophysics Data System (ADS)

    Guedda, M.; Sriti, M.; Achemlal, D.

    2014-08-01

    The main goal of this paper is to re-exam a class of exact solutions for the two-dimensional free convection boundary layers induced by a heated vertical plate embedded in a saturated porous medium with an exponential decaying heat generation. The temperature distribution of the plate has been assumed to vary as a power of the axial coordinate measured from the leading edge of the plate and subjected to an applied lateral mass flux. The boundary layer equations are solved analytically and numerically using a fifth-order Runge-Kutta scheme coupled with the shooting iteration method. As for the classical problem without internal heat generation, it is proved that multiple (unbounded) solutions arise for any and for any suction/injection parameter. For such solutions, the asymptotic behavior as the similarity variable approaches infinity is determined.

  14. Heat extraction for the CSPonD thermal storage unit

    E-print Network

    Rojas, Folkers Eduardo

    2011-01-01

    Three coiled tube heat exchanger prototypes were designed to extract heat from containers holding 0.5 kg, 2.3 kg, and 10.5 kg of Sodium Nitrate-Potassium Nitrate salt. All of the prototypes were left with an open surface ...

  15. Thermal energy storage heat exchanger: molten salt heat exchanger design for utility power plants. Final report, July 1976July 1977

    Microsoft Academic Search

    A. Ferarra; G. Yenetchi; R. Haslett; R. Kosson

    1977-01-01

    The use of thermal energy storage (TES) in the latent heat of molten salts as a means of conserving fossil fuels and lowering the cost of electric power was evaluated. Public utility systems provided electric power on demand. This demand is generally maximum during late weekday afternoons, with considerably lower overnight and weekend loads. Typically, the average demand is only

  16. Effects of the heat transfer fluid velocity on the storage characteristics of a cylindrical latent heat energy storage system: a numerical study

    NASA Astrophysics Data System (ADS)

    Ogoh, Wilson; Groulx, Dominic

    2012-03-01

    A numerical study of the effects of the thermal fluid velocity on the storage characteristics of a cylindrical latent heat energy storage system (LHESS) was conducted. Due to the low thermal conductivity of phase change materials (PCMs) used in LHESS, fins were added to the system to increase the rate of heat transfer and charging. Finite elements were used to implement the developed numerical method needed to study and solve for the phase change heat transfer (melting of PCM) encountered in a LHESS during charging. The effective heat capacity method was applied in order to account for the large amount of latent energy stored during melting of the PCM and the moving interface between the solid and liquid phases. The effects of the heat transfer fluid (HTF) velocity on the melting rate of the PCM were studied for configurations having between 0 and 18 fins. Results show that the overall heat transfer rate to the PCM increases with an increase in the HTF velocity. However, the effect of the HTF velocity was observed to be small in configurations having very few fins, owing to the large residual thermal resistance offered by the PCM. However, the effect of the HTF velocity becomes more pronounced with addition of fins; since the thermal resistance on the PCM side of the LHESS is significantly reduce by the large number of fins in the system.

  17. Study on Heat Transfer Characteristics of Phase-Change Energy Storage Unit for Thermal Management

    NASA Astrophysics Data System (ADS)

    Du, Yanxia; Xiao, Guangming; Gui, Yewei; Liu, Lei; Zhang, Lina; Yu, Mingxing

    2014-08-01

    The objective of the study was to investigate the heat transfer characteristics of a phase-change energy storage unit for thermal management. Considering the conduction in the solid and natural convection in the liquid, a physical and mathematical model for heat transfer was formulated. The governing conservation equations were solved using the finite-volume method on fixed grids. An enthalpy-porosity method was used for modeling the melting phenomenon of a phase-change energy storage unit. The time and space movement of the phase front, the temperature distribution, and the heat dissipation rate have been analyzed based on the model. The influence of the unit geometry, heat source location, and types of phase-change materials on the thermal performance of the energy storage unit were investigated. The model and numerical method were evaluated by comparing the numerical predictions with the experimental results. There was found to be excellent agreement between the calculation and experiment, indicating that the numerical method for heat transfer simulation of a phase-change energy storage unit is accurate. The results from the analysis elucidate the thermal performance of the phase-change energy storage unit and will provide the basis for the design and optimization of thermal management systems.

  18. Evaluation of the HB&L System for the Microbiological Screening of Storage Medium for Organ-Cultured Corneas.

    PubMed

    Camposampiero, D; Grandesso, S; Zanetti, E; Mazzucato, S; Solinas, M; Parekh, M; Frigo, A C; Gion, M; Ponzin, D

    2013-01-01

    Aims. To compare HB&L and BACTEC systems for detecting the microorganisms contaminating the corneal storage liquid preserved at 31°C. Methods. Human donor corneas were stored at 4°C followed by preservation at 31°C. Samples of the storage medium were inoculated in BACTEC Peds Plus/F (aerobic microorganisms), BACTEC Plus Anaerobic/F (anaerobic microorganisms), and HB&L bottles. The tests were performed (a) after six days of storage, (b) end of storage, and (c) after 24 hours of preservation in deturgescent liquid sequentially. 10,655 storage and deturgescent media samples were subjected to microbiological control using BACTEC (6-day incubation) and HB&L (24-hour incubation) systems simultaneously. BACTEC positive/negative refers to both/either aerobic and anaerobic positives/negatives, whereas HB&L can only detect the aerobic microbes, and therefore the positives/negatives depend on the presence/absence of aerobic microorganisms. Results. 147 (1.38%) samples were identified positive with at least one of the two methods. 127 samples (134 identified microorganisms) were positive with both HB&L and BACTEC. 14 HB&L+/BACTEC- and 6 BACTEC+/HB&L- were identified. Sensitivity (95.5%), specificity (99.8%), and positive (90.1%) and negative predictive values (99.9%) were high with HB&L considering a 3.5% annual contamination rate. Conclusion. HB&L is a rapid system for detecting microorganisms in corneal storage medium in addition to the existing methods. PMID:24069532

  19. Evaluation of the HB&L System for the Microbiological Screening of Storage Medium for Organ-Cultured Corneas

    PubMed Central

    Camposampiero, D.; Grandesso, S.; Zanetti, E.; Mazzucato, S.; Solinas, M.; Parekh, M.; Frigo, A. C.; Gion, M.; Ponzin, D.

    2013-01-01

    Aims. To compare HB&L and BACTEC systems for detecting the microorganisms contaminating the corneal storage liquid preserved at 31°C. Methods. Human donor corneas were stored at 4°C followed by preservation at 31°C. Samples of the storage medium were inoculated in BACTEC Peds Plus/F (aerobic microorganisms), BACTEC Plus Anaerobic/F (anaerobic microorganisms), and HB&L bottles. The tests were performed (a) after six days of storage, (b) end of storage, and (c) after 24 hours of preservation in deturgescent liquid sequentially. 10,655 storage and deturgescent media samples were subjected to microbiological control using BACTEC (6-day incubation) and HB&L (24-hour incubation) systems simultaneously. BACTEC positive/negative refers to both/either aerobic and anaerobic positives/negatives, whereas HB&L can only detect the aerobic microbes, and therefore the positives/negatives depend on the presence/absence of aerobic microorganisms. Results. 147 (1.38%) samples were identified positive with at least one of the two methods. 127 samples (134 identified microorganisms) were positive with both HB&L and BACTEC. 14 HB&L+/BACTEC? and 6 BACTEC+/HB&L? were identified. Sensitivity (95.5%), specificity (99.8%), and positive (90.1%) and negative predictive values (99.9%) were high with HB&L considering a 3.5% annual contamination rate. Conclusion. HB&L is a rapid system for detecting microorganisms in corneal storage medium in addition to the existing methods. PMID:24069532

  20. Development of an integrated heat pipe-thermal storage system for a solar receiver

    NASA Technical Reports Server (NTRS)

    Keddy, E.; Sena, J. Tom; Merrigan, M.; Heidenreich, Gary; Johnson, Steve

    1988-01-01

    An integrated heat pipe-thermal storage system was developed as part of the Organic Rankine Cycle Solar Dynamic Power System solar receiver for space station application. The solar receiver incorporates potassium heat pipe elements to absorb and transfer the solar energy within the receiver cavity. The heat pipes contain thermal energy storage (TES) canisters within the vapor space with a toluene heater tube used as the condenser region of the heat pipe. During the insolation period of the earth orbit, solar energy is delivered to the heat pipe. Part of this thermal energy is delivered to the heater tube and the balance is stored in the TES units. During the eclipse period of earth orbit, the stored energy in the TES units is transferred by the potassium vapor to the toluene heater tube. A developmental heat pipe element was constructed that contains axial arteries and a distribution wick connecting the toluene heater and the TES units to the solar insolation surface of the heat pipe. Tests were conducted to demonstrate the heat pipe, TES units, and the heater tube operation. The heat pipe element was operated at design input power of 4.8 kW. Thermal cycle tests were conducted to demonstrate the successful charge and discharge of the TES units. Axial power flux levels up to 15 watts/sq cm were demonstrated and transient tests were conducted on the heat pipe element. Details of the heat pipe development and test procedures are presented.

  1. Basic Research on a Latent Heat Thermal Energy Storage by Direct Contact Melting and Solidification

    NASA Astrophysics Data System (ADS)

    Saito, Akihiro; Saito, Akio; Utaka, Yoshio; Okuda, Kenichi; Katayama, Kozo

    A basic experimental research on a latent heat thermal energy storage system, utilizing a simple and effective heat exchange mechanism by a direct contact between the phase change material (PCM) and the heat transfer fluid (HTF) , was shown. In this report, authors proposed the direct contact latent heat thermal energy storage system using industrial paraffin and n-Eicosane as the PCM, and using water as the HTF. The observations were performed concerning the HTF separation from the solid PCM in the solidification process (heat discharging process), and concerning the water pass formation within the solid PCM. Then, it was confirmed that the system worked effectively by using n-Eicosane as the PCM. And authors discussed the mechanism of direct contact solidification process from experimental results.

  2. Natural element method for radiative heat transfer in a semitransparent medium with irregular geometries

    SciTech Connect

    Zhang, Yong [School of Energy Science and Engineering, Harbin Institute of Technology, 92 West Dazhi Street, Harbin 150001 (China)] [School of Energy Science and Engineering, Harbin Institute of Technology, 92 West Dazhi Street, Harbin 150001 (China); Yi, Hong-Liang, E-mail: yihongliang@hit.edu.cn [School of Energy Science and Engineering, Harbin Institute of Technology, 92 West Dazhi Street, Harbin 150001 (China)] [School of Energy Science and Engineering, Harbin Institute of Technology, 92 West Dazhi Street, Harbin 150001 (China); Tan, He-Ping, E-mail: tanheping@hit.edu.cn [School of Energy Science and Engineering, Harbin Institute of Technology, 92 West Dazhi Street, Harbin 150001 (China)] [School of Energy Science and Engineering, Harbin Institute of Technology, 92 West Dazhi Street, Harbin 150001 (China)

    2013-05-15

    This paper develops a numerical solution to the radiative heat transfer problem coupled with conduction in an absorbing, emitting and isotropically scattering medium with the irregular geometries using the natural element method (NEM). The walls of the enclosures, having temperature and mixed boundary conditions, are considered to be opaque, diffuse as well as gray. The NEM as a meshless method is a new numerical scheme in the field of computational mechanics. Different from most of other meshless methods such as element-free Galerkin method or those based on radial basis functions, the shape functions used in NEM are constructed by the natural neighbor interpolations, which are strictly interpolant and the essential boundary conditions can be imposed directly. The natural element solutions in dealing with the coupled heat transfer problem for the mixed boundary conditions have been validated by comparison with those from Monte Carlo method (MCM) generated by the authors. For the validation of the NEM solution to radiative heat transfer in the semicircular medium with an inner circle, the results by NEM have been compared with those reported in the literatures. For pure radiative transfer, the upwind scheme is employed to overcome the oscillatory behavior of the solutions in some conditions. The steady state and transient heat transfer problem combined with radiation and conduction in the semicircular enclosure with an inner circle are studied. Effects of various parameters such as the extinction coefficient, the scattering albedo, the conduction–radiation parameter and the boundary emissivity are analyzed on the radiative and conductive heat fluxes and transient temperature distributions.

  3. Theoretical analysis of screened heat pipes for medium and high temperature solar applications

    NASA Astrophysics Data System (ADS)

    Di Marco, P.; Filippeschi, S.; Franco, A.; Jafari, D.

    2014-11-01

    A mathematical model is applied to study the cylindrical heat pipes (HPs) behaviour when it is exposed to higher heat input at the evaporator for solar collector applications. The steady state analytical model includes two-dimensional heat conduction in the wall, the liquid flow in the wick and vapour hydrodynamics, and can be used to evaluate the working limits and to optimize the HP. The results of the analytical model are compared with numerical and experimental results available in literature, with good agreement. The effects of heat transfer coefficient, power input, evaporator length, pipe diameter, wick thickness and effective pore radius on the vapour temperature, maximum pressure drop and maximum heat transfer capability (HTC) of the HP are studied. The analysis shows that wick thickness plays an important role in the enhancement of HTC. Results show that it is possible to improve HTC of a HP by selecting the appropriate wick thickness, effective pore radius, and evaporator length. The parametric investigations are aimed to determine working limits and thermal performance of HP for medium temperature solar collector application.

  4. Thermal stability of a rotating saturated porous medium heated from below

    NASA Astrophysics Data System (ADS)

    Desaive, Thomas; Lebon, Georgy; Hennenberg, Marcel; Istasse, Eric

    2001-11-01

    The study of convection in rotating porous medium is a subject of fundamental and practical interest since it exists in numerous applications such as centrifugal filtration processes, food engineering as well as in geophysics. In this work, we consider a saturated porous medium of infinite horizontal extent described by Brinkman's model which accounts for friction caused by macroscopic shear. The system heated from below in the gravity field and sandwiched between two rigid walls is rotating around a vertical axis. The effect of rotation is restricted to the Coriolis acceleration, neglecting the centrifugal buoyancy. We present a linear stability analysis of this model and derive the critical threshold for both stationary and overstable convection. The effect of several dimensionless groups on the critical values is detailed while a comparison with earlier works and a model using Darcy's law is also performed.

  5. Transfer function of a sensible-heat storage element in periodic regime

    NASA Astrophysics Data System (ADS)

    Fourcher, B.; Saint-Blanquet, C.

    1980-09-01

    This paper deals with the extraction of the mean component of a periodic thermal power (solar energy for example). It is shown that such a filtering may be achieved by introducing a solid sensible-heat thermal storage unit. A theoretical model has been defined for a specific heat storage configuration composed of a number of rectangular cross-section channels for the flowing fluid connected parallel and separated by the solid storage material. The model yields basic physical conclusions for the temperature fluctuations at the exit extremity and makes it possible to define an optimal geometry for the designs. The results are set explicitly for two different fluid-storage material couples: air-alumina and air-refractory brick.

  6. Evaluation of bone marrow-derived mesenchymal stem cells after cryopreservation and hypothermic storage in clinically safe medium.

    PubMed

    Ginis, Irene; Grinblat, Borislava; Shirvan, Mitchell H

    2012-06-01

    Achievements in tissue engineering using mesenchymal stem cells (MSC) demand a clinically acceptable "off-the-shelf" cell therapy product. Efficacy of cryopreservation of human bone marrow-derived MSC in clinically safe, animal product-free medium containing 2%, 5%, and 10% dimethyl sulfoxide (DMSO) was evaluated by measuring cell recovery, viability, apoptosis, proliferation rate, expression of a broad panel of MSC markers, and osteogenic differentiation. Rate-controlled freezing in CryoStor media was performed in a programmable cell freezer. About 95% of frozen cells were recovered as live cells after freezing in CryoStor solutions with 5% and 10% DMSO followed by storage in liquid nitrogen for 1 month. Cell recovery after 5 months storage was 72% and 80% for 5% and 10% DMSO, respectively. Measurements of caspase 3 activity demonstrated that 15.5% and 12.8% of cells after 1 month and 18.3% and 12.9% of cells after 5 months storage in 5% and 10% DMSO, respectively, were apoptotic. Proliferation of MSC recovered after cryopreservation was measured during 2 weeks post-plating. Proliferation rate was not compromised and was even enhanced. Cryopreservation did not alter expression of MSC markers. Quantitative analysis of alkaline phosphatase (ALP) activity, ALP surface expression and Ca?? deposition in previously cryopreserved MSC and then differentiated for 3 weeks in osteogenic medium demonstrated the same degree of osteogenic differentiation as in unfrozen parallel cultures. Cell viability and functional parameters were analyzed in MSC after short-term storage at 4°C in HypoThermosol-FRS solution, also free of animal products. Hypothermic storage for 2 and 4 days resulted in about 100% and 85% cell recovery, respectively, less than 10% of apoptotic cells, and normal proliferation, marker expression, and osteogenic potential. Overall, our results demonstrate that human MSC could be successfully cryopreserved for banking and clinical applications and delivered to the bedside in clinically safe protective reagents. PMID:22196031

  7. Numerical modeling of coupled thermal chemical reactive transport: simulation of a heat storage system

    NASA Astrophysics Data System (ADS)

    Shao, H.; Watanabe, N.; Singh, A. K.; Nagel, T.; Linder, M.; Woerner, A.; Kolditz, O.

    2012-12-01

    As a carbon-free energy supply technology, the operation time and final energy output of thermal solar power plants can be greatly extended if efficient thermal storage systems are applied. One of the proposed design of such system is to utilize reversible thermochemical reactions and its embedded reaction enthalpy, e.g. the Ca(OH)2/CaO hydration circle, in a fixed-bed gas-solid reactor (Schaube et al. 2011) The modeling of such a storage system involves multiple strongly-coupled physical and chemical processes. Seepage velocity is calculated by the nonlinear Forchheimer law. Gas phase density and viscosity are temperature, pressure and composition dependent. Also, heat transfer between gas and solid phases is largely influenced by the exothermal heat produced by the hydration of calcium oxide. Numerical solution of four governing PDEs include the mass balance, reactive transport, heat balance equations for gas and solid phases, which are implemented into the open source scientific software OpenGeoSys in a monolithic way. Based on it, a 2D numerical model, considering the boundary heat loss of the system, was set up to simulate the energy-storage and release circle. The high performance computing techniques were employed in two stages. First, the dynamic behavior of the heat storage system is simulated on a parallel platform. Second, a large number of processors are employed to perform sensitivity analysis, whereas the reaction rates and efficiency factor of heat transfer are parameterized so that the measured and simulated temperature profile fit with each other. The model showed that heat transfer coefficient between solid and gas phase, grain size of the filling material will influence the final performance greatly. By varying these factors, the calibrated model will be further applied to optimize the design of such energy storage system.

  8. Preliminary Analysis of a Solar Heat Pump System with Seasonal Storage for Heating and Cooling

    E-print Network

    Yu, G.; Chen, P.; Dalenback, J.

    2006-01-01

    will be reduced to Rv in the following sections) is 2. That means the volume of seasonal storage tank is 5800m3. After all main features of this system was determined, some computer routines were made, and many simulations were conducted hour by hour... 6 1550 200 270 7 1840 0 0 8 1270 0 0 9 130 0 0 3. EFFECTS OF SEASONAL STORAGE CAPACITY The volume of seasonal storage is an important parameter of the solar system. This paper use the ratio of storage volume to collector area (Rv) to study...

  9. Optimal design and placement of serpentine heat exchangers for indirect heat withdrawal, inside flat plate integrated collector storage solar water heaters (ICSSWH)

    Microsoft Academic Search

    K. P. Gertzos; Y. G. Caouris; Th. Panidis

    2010-01-01

    Parameters that affect the temperature at which service hot water (SHW) is offered by an immersed tube heat exchanger (HX), inside a flat plate Integrated Collector Storage Solar Water Heater (ICSSWH), are examined numerically, by means of Computational Fluid Dynamics (CFD) analysis. The storage water is not refreshed and serves for heat accumulation. Service hot water is drawn off indirectly,

  10. A feasible way to remove the heat during adsorptive methane storage.

    PubMed

    Gütlein, Stefan; Burkard, Christoph; Zeilinger, Johannes; Niedermaier, Matthias; Klumpp, Michael; Kolb, Veronika; Jess, Andreas; Etzold, Bastian J M

    2015-01-01

    Methane originating from biogas or natural gas is an attractive and environmentally friendly alternative to gasoline. Adsorption is seen as promising storage technology, but the heat released limits fast filling of these systems. Here a lab scale adsorptive methane storage tank, capable to study the temperature increase during fast filling, was realized. A variation of the filling time from 1 h to 31 s, showed a decrease of the storage capacity of 14% and temperature increase of 39.6 °C. The experimental data could be described in good accordance with a finite element simulation solving the transient mass, energy, and impulse balance. The simulation was further used to extrapolate temperature development in real sized car tanks and for different heat pipe scenarios, resulting in temperature rises of approximately 110 °C. It could be clearly shown, that with heat conductivity as solei mechanism the heat cannot be removed in acceptable time. By adding an outlet to the tank a feed flow cooling with methane as heat carrier was realized. This setup was proofed in simulation and lab scale experiments to be a promising technique for fast adsorbent cooling and can be crucial to leverage the full potential of adsorptive methane gas storage. PMID:25485691

  11. Photoionization and heating of a supernova-driven turbulent interstellar medium

    NASA Astrophysics Data System (ADS)

    Barnes, J. E.; Wood, Kenneth; Hill, Alex S.; Haffner, L. M.

    2014-06-01

    The diffuse ionized gas (DIG) in galaxies traces photoionization feedback from massive stars. Through three-dimensional photoionization simulations, we study the propagation of ionizing photons, photoionization heating and the resulting distribution of ionized and neutral gas within snapshots of magnetohydrodynamic simulations of a supernova-driven turbulent interstellar medium. We also investigate the impact of non-photoionization heating on observed optical emission line ratios. Inclusion of a heating term which scales less steeply with electron density than photoionization is required to produce diagnostic emission line ratios similar to those observed with the Wisconsin H? Mapper. Once such heating terms have been included, we are also able to produce temperatures similar to those inferred from observations of the DIG, with temperatures increasing to above 15 000 K at heights |z| ? 1 kpc. We find that ionizing photons travel through low-density regions close to the mid-plane of the simulations, while travelling through diffuse low-density regions at large heights. The majority of photons travel small distances (?100 pc); however some travel kiloparsecs and ionize the DIG.

  12. Buoyancy and chemical reaction effects on MHD mixed convection heat and mass transfer in a porous medium with thermal radiation and Ohmic heating

    Microsoft Academic Search

    Dulal Pal; Babulal Talukdar

    2010-01-01

    The combined effect of mixed convection with thermal radiation and chemical reaction on MHD flow of viscous and electrically conducting fluid past a vertical permeable surface embedded in a porous medium is analyzed. The heat equation includes the terms involving the radiative heat flux, Ohmic dissipation, viscous dissipation and the internal absorption whereas the mass transfer equation includes the effects

  13. Chemically driven heat pumps for solar thermal storage

    Microsoft Academic Search

    P. O'd. Offenhartz

    1978-01-01

    Methods of storing solar thermal energy by means of chemical reactions in heat-pump cycles are reviewed. These chemical reactions involve one or two solid (or, in one case, liquid) substrates plus a carrier gas. Charging the system involves decomposing a solid (or liquid) complex into a solid (or liquid) plus a gas; the gas in turn liquefies under pressure -

  14. Shallow heat injection and storage experiment monitored with electrical resistivity tomography and simulated with heat transport model

    NASA Astrophysics Data System (ADS)

    Hermans, T.; Daoudi, M.; Vandenbohede, A.; Lebbe, L.; Nguyen, F. H.

    2011-12-01

    Groundwater resources are increasingly used around the world as geothermal systems. Understanding physical processes and quantification of parameters determining heat transport in porous media is therefore important. To monitor the geothermal behavior of groundwater systems and to estimate the governing parameters, we rely mainly on borehole observations of the temperature field at a few locations (temperature logs or thermal response test). In analogy to research in hydrogeophysics, geophysical methods may be useful in order to yield additional information for thermal properties estimation with greater coverage than conventional wells. We report a heat transport study during a shallow heat injection and storage field test. Heated water (temperature of 50°C) was injected for 6 days at the rate of 80 l/h in a 10.5°C aquifer. Since bulk electrical resistivity variations can bring important information on temperature changes in aquifers (water electrical conductivity increases about 2%/°C around 25°C), we monitored the test with surface electrical resistivity tomography and we demonstrate its ability to monitor spatially the temperature variation. Time-lapse electrical imaging clearly shows the successive decrease and increase in bulk electrical resistivity of the plume of heated water, during the injection and the storage phase respectively. This information enabled to calibrate the conceptual flow and heat model used to simulate the test (using SEAWAT). Inverted resistivity values are validated with borehole electromagnetic measurements (EM39) and are in agreement with the temperature logs used to calibrate the parameters of the thermo-hydrogeological model. This field work demonstrates that surface electrical resistivity tomography can monitor heat and storage experiments in shallow aquifers. These results could potentially lead to a number of practical applications, such as the monitoring or the design of shallow geothermal systems. Moreover, sensitivity analyses and collinear diagnostic were used to assess the pertinence of the flow and heat model parameters. The most sensitive parameter is the thermal conductivity of the solid followed by the porosity, heat capacity of the solid and the longitudinal dispersivity. This indicates the predominance of conductive transport during the storage phase over the convective transport during the injection phase. These values rely only on temperature logs and more parameters could be derived or more robust values could be achieved with the use of geophysical data in a coupled inversion scheme.

  15. Scenario Development and Analysis of Hydrogen as a Large-Scale Energy Storage Medium (Presentation)

    SciTech Connect

    Steward, D. M.

    2009-06-10

    The conclusions from this report are: (1) hydrogen has several important advantages over competing technologies, including - very high storage energy density (170 kWh/m{sup 3} vs. 2.4 for CAES and 0.7 for pumped hydro) which allows for potential economic viability of above-ground storage and relatively low environmental impact in comparison with other technologies; and (2) the major disadvantage of hydrogen energy storage is cost but research and deployment of electrolyzers and fuel cells may reduce cost significantly.

  16. Two-tank working gas storage system for heat engine

    DOEpatents

    Hindes, Clyde J. (Troy, NY)

    1987-01-01

    A two-tank working gas supply and pump-down system is coupled to a hot gas engine, such as a Stirling engine. The system has a power control valve for admitting the working gas to the engine when increased power is needed, and for releasing the working gas from the engine when engine power is to be decreased. A compressor pumps the working gas that is released from the engine. Two storage vessels or tanks are provided, one for storing the working gas at a modest pressure (i.e., half maximum pressure), and another for storing the working gas at a higher pressure (i.e., about full engine pressure). Solenoid valves are associated with the gas line to each of the storage vessels, and are selectively actuated to couple the vessels one at a time to the compressor during pumpdown to fill the high-pressure vessel with working gas at high pressure and then to fill the low-pressure vessel with the gas at low pressure. When more power is needed, the solenoid valves first supply the low-pressure gas from the low-pressure vessel to the engine and then supply the high-pressure gas from the high-pressure vessel. The solenoid valves each act as a check-valve when unactuated, and as an open valve when actuated.

  17. Numerical simulation of a shell-and-tube latent heat thermal energy storage unit

    Microsoft Academic Search

    M Lacroix

    1993-01-01

    A theoretical model was developed to predict the transient behavior of a shell-and-tube storage unit with the phase change material (PCM) on the shell side and the heat transfer fluid (HTF) circulating inside the tubes. The multidimensional phase change problem is tackled with an enthalpy-based method coupled to the convective heat transfer from the HTF. The numerical predictions are validated

  18. The Effect of Storage Time and Humidity on Mechanical and Physical Properties of Medium Density Fiberboard (MDF) from Oil Palm Empty Fruit Bunch and Rubberwood

    Microsoft Academic Search

    H. P. S. Abdul Khalil; M. Y. Nur Firdaus; M. Anis; R. Ridzuan

    2008-01-01

    Commercial medium density fiberboard (MDF) was produced using rubberwood and oil palm empty fruit bunch (OPEFB) based on oven dried weight. Relative humidities of 65%, 93% with fixed temperature at 20°C, and normal condition was used for storage of the boards. The effects of storage time and relative humidity of MDF were assessed by measuring the changes of the board

  19. Analysis of novel, above-ground thermal energy storage concept utilizing low-cost, solid medium

    E-print Network

    Barineau, Mark Michael

    2010-01-01

    Clean energy power plants cannot effectively match peak demands without utilizing energy storage technologies. Currently, several solutions address short term demand cycles, but little work has been done to address seasonal ...

  20. The effect of impurities on the melting temperature and the heat of fusion of latent heat storage materials

    NASA Astrophysics Data System (ADS)

    Sohns, J.; Seifert, B.; Hahne, E.

    1981-03-01

    Thermophysical properties of four normal paraffins (tetradecane, hexadecane, octadecane, eicosane) and three fatty acids (lauric acid, palmitic acid, stearic acid) were determined experimentally using a modified differential-thermoanalysis technique. For calibration of the measuring device, literature data in the temperature range from 5 to 70°C of six of these substances of at least 99% purity were used. Melting temperature, heat of fusion, and specific heat of a number of these “pure” and “technically pure” organic compounds were measured and compared to determine the effect of impurities and to give values of the application range of the properties required for the construction of thermal storage equipment.

  1. Effect on pH heating medium on the thermal resistance of Bacillus stearothermophilus spores.

    PubMed

    López, M; González, I; Condón, S; Bernardo, A

    1996-01-01

    The influence of the pH of heating medium on heat resistance of Bacillus stearothermophilus spores (ATCC 7953, 12980, 15951 and 15952) were studied. The pH values tested were: 4.0, 5.0, 6.0 and 7.0 at temperatures of 115, 120, 125, 130 and 135 degrees C. It was found that at low treatment temperatures (115 degrees C) D-values decreased between 7- and 10-fold with 7953, 12980 and 15951 strains and about 23-fold with 15952 strain when pH dropped from 7.0 to 4.0. At highest treatment temperatures (135 degrees C) D-values obtained with pH 6.0 and 7.0 did not show any significant statistical differences (p > 0.05). z-Values appeared to be higher when the medium was acidified, ranging from 7.58 to 8.20 and 9.43 10.0 for spores suspended in McIlvaine buffer pH 7.0 and pH 4.0, respectively, although the difference was not statistically significant. Heat resistance of strain ATCC 7953 at 120, 128, and 135 degrees C in asparagus purée and tomato purée at pH 5.0 under continuous monitoring of pH was also determined. D-values obtained in asparagus purée were similar to those obtained in buffer at the same pH, whereas those observed in tomato purée were found to be lower. PMID:8652348

  2. Development of an integrated heat pipe-thermal storage system for a solar receiver

    NASA Technical Reports Server (NTRS)

    Keddy, E. S.; Sena, J. T.; Merrigan, M. A.; Heidenreich, G.; Johnson, S.

    1987-01-01

    The Organic Rankine Cycle (ORC) Solar Dynamic Power System (SDPS) is one of the candidates for Space Station prime power application. In the low Earth orbit of the Space Station approximately 34 minutes of the 94-minute orbital period is spent in eclipse with no solar energy input to the power system. For this period the SDPS will use thermal energy storage (TES) material to provide a constant power output. An integrated heat-pipe thermal storage receiver system is being developed as part of the ORC-SDPS solar receiver. This system incorporates potassium heat pipe elements to absorb and transfer the solar energy within the receiver cavity. The heat pipes contain the TES canisters within the potassium vapor space with the toluene heater tube used as the condenser region of the heat pipe. During the insolation period of the Earth orbit, solar energy is delivered to the heat pipe in the ORC-SDPS receiver cavity. The heat pipe transforms the non-uniform solar flux incident in the heat pipe surface within the receiver cavity to an essentially uniform flux at the potassium vapor condensation interface in the heat pipe. During solar insolation, part of the thermal energy is delivered to the heater tube and the balance is stored in the TES units. During the eclipse period of the orbit, the balance stored in the TES units is transferred by the potassium vapor to the toluene heater tube.

  3. Heat-Storage Modules Containing LiNO3-3H2O and Graphite Foam

    NASA Technical Reports Server (NTRS)

    Bootle, John

    2008-01-01

    A heat-storage module based on a commercial open-cell graphite foam (Poco-Foam or equivalent) imbued with lithium nitrate trihydrate (LiNO3-3H2O) has been developed as a prototype of other such modules for use as short-term heat sources or heat sinks in the temperature range of approximately 28 to 30 C. In this module, the LiNO3-3H2O serves as a phase-change heat-storage material and the graphite foam as thermally conductive filler for transferring heat to or from the phase-change material. In comparison with typical prior heat-storage modules in which paraffins are the phase-change materials and aluminum fins are the thermally conductive fillers, this module has more than twice the heat-storage capacity per unit volume.

  4. Thermal energy storage for low grade heat in the organic Rankine cycle

    NASA Astrophysics Data System (ADS)

    Soda, Michael John

    Limits of efficiencies cause immense amounts of thermal energy in the form of waste heat to be vented to the atmosphere. Up to 60% of unrecovered waste heat is classified as low or ultra-low quality, making recovery difficult or inefficient. The organic Rankine cycle can be used to generate mechanical power and electricity from these low temperatures where other thermal cycles are impractical. A variety of organic working fluids are available to optimize the ORC for any target temperature range. San Diego State University has one such experimental ORC using R245fa, and has been experimenting with multiple expanders. One limitation of recovering waste heat is the sporadic or cyclical nature common to its production. This inconsistency makes sizing heat recovery ORC systems difficult for a variety of reasons including off-design-point efficiency loss, increased attrition from varying loads, unreliable outputs, and overall system costs. Thermal energy storage systems can address all of these issues by smoothing the thermal input to a constant and reliable level and providing back-up capacity for times when the thermal input is deactivated. Multiple types of thermal energy storage have been explored including sensible, latent, and thermochemical. Latent heat storage involves storing thermal energy in the reversible phase change of a phase change material, or PCM, and can have several advantages over other modalities including energy storage density, cost, simplicity, reliability, relatively constant temperature output, and temperature customizability. The largest obstacles to using latent heat storage include heat transfer rates, thermal cycling stability, and potentially corrosive PCMs. Targeting 86°C, the operating temperature of SDSU's experimental ORC, multiple potential materials were explored and tested as potential PCMs including Magnesium Chloride Hexahydrate (MgCl2?6H2O), Magnesium Nitrate Hexahydrate (Mg(NO3)2?6H 2O), montan wax, and carnauba wax. The addition of graphite to augment heat transfer rates was also tested. Melting and solidification temperatures largely matched predictions. The magnesium salts were found to be less stable under thermal cycling than the waxes. Graphite was only soluble in the waxes. Mixtures of magnesium salts and waxes yielded a layered composite with the less dense waxes creating a sealing layer over the salt layer that significantly increased the stability of the magnesium salts. Research into optimum heat exchangers and storage vessels for these applications indicates that horizontally oriented aluminum pipes with vertically oriented aluminum fins would be the best method of storing and retrieving energy. Fin spacing can be predicted by an equation based on target temperatures and PCM characteristics.

  5. Cyclic heat transfer in a novel storage unit of multiple phase change materials

    Microsoft Academic Search

    Zhen-Xiang Gong; Arun S. Mujumdar

    1996-01-01

    A novel storage unit of multiple phase change materials (PCMs) is developed. The physical module consists of a tube which is surrounded by an external coaxial cylinder made up of several segments of different PCMs with different melting points. A heat transfer fluid flows through the tube to store-extract thermal energy from the PCMs. A finite element model has been

  6. Evaluation of industrial advanced heat-recovery\\/thermal-energy-storage systems, volume 2

    Microsoft Academic Search

    H. R. McChesney; R. W. Bass; A. M. Landerman; T. N. Obee; C. T. Sgamboti

    1982-01-01

    The recovery of waste heat from industrial processes offers significant opportunity for energy conservation provided the available energy source can be matched with a compatible energy consuming sink or end-use process. This investigation involved: examining plant and process energy data acquired during on-site visits to 12 industrial plants from which 24 candidate applications were identified where thermal energy storage would

  7. Heat flow in a horizontal solar thermal storage tank with an auxiliary heater

    Microsoft Academic Search

    A.-J. N Khalifa; M. A Hussian

    2002-01-01

    An experimental and numerical study is conducted to verify the applicability of a one dimensional heat flow model in a horizontal storage tank of a thermosyphon solar system equipped with an auxiliary heater. Measurements of temperature are conducted in the vertical, axial and radial directions to examine the temperature stratification in the tank. A maximum average temperature deviation of 3.6%

  8. DYNAMICS OF WATER TRANSPORT AND STORAGE IN CONIFERS STUDIED WITH DEUTERIUM AND HEAT TRACING TECHNIQUES

    EPA Science Inventory

    The volume and complexity of their vascular systems make the dynamics of long-distance water transport difficult to study. We used heat and deuterated water (D2O) as tracers to characterize whole-tree water transport and storage properties in individual trees belonging to the co...

  9. Seismic modeling and analysis of a prototype heated nuclear waste storage tunnel, Yucca Mountain, Nevada

    E-print Network

    Snieder, Roel

    Seismic modeling and analysis of a prototype heated nuclear waste storage tunnel, Yucca Mountain rock surrounding a tunnel in Yucca Mountain tuff and com- pared the results with field data obtained waves diffracted around the tunnel in the region of changing velocity. INTRODUCTION The Yucca Mountain

  10. Fuel-efficiency of hydrogen and heat storage technologies for integration of fluctuating renewable energy sources

    Microsoft Academic Search

    Brian Vad Mathiesen; Henrik Lund

    2005-01-01

    This paper presents the methodology and results of analysing the use of different energy storage technologies in the task of integration of fluctuating renewable energy sources (RES) into the electricity supply. The analysis is done on the complete electricity system including renewable energy sources as well as power plants and CHP (combined heat and power production). Emphasis is put on

  11. Review of mathematical modeling on latent heat thermal energy storage systems using phase-change material

    Microsoft Academic Search

    Prashant Verma; Varun; S. K. Singal

    2008-01-01

    Mathematical modeling of a latent heat thermal energy storage system (LHTES) was used for the optimum material selection and to assist in the optimal designing of the systems. In this paper, two types of models are mainly discussed, on the basis of first law and second law of thermodynamics. The important characteristics of different models and their assumptions used are

  12. Office Building Uses Ice Storage, Heat Recovery, and Cold-Air Distribution

    E-print Network

    Tackett, R. K.

    1989-01-01

    Ice storage offers many opportunities to use other tcchnologies, such as heat recovery and cold-air distribution. In fact, by using them, the designer can improve the efficiency and lower the construction cost of an ice system. This paper presents a...

  13. A general model for analyzing the thermal characteristics of a class of latent heat thermal energy storage systems

    Microsoft Academic Search

    Kang Yanbing; Zhang Yinping; Jiang Yi; Zhu Yingxin

    1999-01-01

    The present study describes and classifies latent heat thermal energy storage (LHTES) systems according to their structural characteristics. A general model is developed for analyzing the thermal characteristics of the various typical LHTES systems to simulate thermal characteristics such as instantaneous heat transfer rate, instantaneous thermal storage capacity, etc. of the various typical LHTES systems. The model can calculate some

  14. Experimental and simulated temperature distribution of an oil-pebble bed thermal energy storage system with a variable heat source

    Microsoft Academic Search

    A. Mawire; M. McPherson

    2009-01-01

    Axial temperature distributions of a thermal energy storage (TES) system under variable electrical heating have been investigated. An electrical hot plate in thermal contact with a hollow copper spiral coil through which the oil flows simulates a solar collector\\/concentrator system. The hot plate heats up the oil which flows through the storage thus charging the TES system at a constant

  15. Short-term storage of canine preantral ovarian follicles using a powdered coconut water (ACP)-based medium.

    PubMed

    Lima, G L; Costa, L L M; Cavalcanti, D M L P; Rodrigues, C M F; Freire, F A M; Fontenele-Neto, J D; Silva, A R

    2010-07-01

    The objective was to investigate the use of powdered coconut water (ACP)-based medium for short-term preservation of canine preantral follicles. Pairs of ovaries from mongrel bitches (n=9) were divided into fragments. One ovarian fragment, treated as a fresh control, was immediately fixed for histological analysis, whereas the other six ovarian fragments were stored either in phosphate-buffered saline (PBS; control group) or ACP medium in isothermal Styrofoam boxes containing biological ice packs. The boxes were sealed and opened only after 12, 24, or 36h. After opening each box, the ovarian fragments were submitted to histological analysis. In total, 12,302 preantral follicles were evaluated, with 64.5% primordial, 33.3% primary, and 2.3% secondary follicles. There were multiple oocytes in 1.3% of the follicles analyzed. At 24h, ACP was more efficient in preserving follicular morphology than PBS (P<0.05). Compared with the fresh control group, a significant reduction in the percentage of morphologically normal ovarian follicles was observed for PBS, starting at 24h; however, the decline started only at 36h for the ACP medium. During the experiment, the temperature inside the isothermal boxes increased from 3 to 9 degrees C (P<0.05), despite a constant room temperature. In conclusion, powdered coconut water (ACP) was an appropriate medium for short-term storage of canine preantral ovarian follicles. PMID:20207405

  16. Comparison of Decay Heat Power of Uranium, Plutonium, and Thorium Spent Fuel at Long-Term Storage

    SciTech Connect

    Gerasimov, Aleksander S.; Bergelson, Boris R.; Zaritskaya, Tamara S.; Tikhomirov, Georgy V. [Institute of Theoretical and Experimental Physics, SSC RF ITEP, Bolshaya Cheremushkinskaya, 25, 117218 Moscow (Russian Federation)

    2002-07-01

    Accumulation and subsequent storage of actinides from uranium, plutonium, and thorium spent fuel of PWR type reactor is discussed in the paper. During period of accumulation 100 or 300 years, actinides are periodically introduced in the storage facility. Subsequent period of 300 000 years is long-term storage without introduction of new portions of spent fuel. This time includes both period of controllable storage and ultimate geological storage. Decay heat power of actinides was calculated. It affects heat removal system of the storage facility. Maximal decay heat power of actinides from plutonium spent fuel corresponding to the end of the period of accumulation of 100 years is 2.5 times higher than that of uranium spent fuel. Maximal decay heat power of actinides from uranium spent fuel is 1.2 times higher than that of thorium spent fuel. (authors)

  17. Energetic and exergetic efficiency of latent heat storage system for greenhouse heating

    Microsoft Academic Search

    A. Ba?çetinçelik; H. H. öztürk; H. Ö. Paksoy; Y. Demirel

    1999-01-01

    In this research, solar energy has been stored using the paraffin with the latent heat technique for heating the plastic greenhouse of 180 m2. Energy and exergy analyses were applied for evaluation of the system efficiency. An average values of the rates of heat and thermal exergy stored into the HSU were 1 740 W and 60 W for the

  18. Two-tank molten salt storage for parabolic trough solar power plants

    Microsoft Academic Search

    Ulf Herrmann; Bruce Kelly; Henry Price

    2004-01-01

    The most advanced thermal energy storage for solar thermal power plants is a two-tank storage system where the heat transfer fluid (HTF) also serves as storage medium. This concept was successfully demonstrated in a commercial trough plant (13.8 MWe SEGS I plant; 120 MWht storage capacity) and a demonstration tower plant (10 MWe Solar Two; 105 MWht storage capacity). However,

  19. [The design of heat dissipation of the field low temperature box for storage and transportation].

    PubMed

    Wei, Jiancang; Suin, Jianjun; Wu, Jian

    2013-02-01

    Because of the compact structure of the field low temperature box for storage and transportation, which is due to the same small space where the compressor, the condenser, the control circuit, the battery and the power supply device are all placed in, the design for heat dissipation and ventilation is of critical importance for the stability and reliability of the box. Several design schemes of the heat dissipation design of the box were simulated using the FLOEFD hot fluid analysis software in this study. Different distributions of the temperature field in every design scheme were constructed intimately in the present study. It is well concluded that according to the result of the simulation analysis, the optimal heat dissipation design is decent for the field low temperature box for storage and transportation, and the box can operate smoothly for a long time using the results of the design. PMID:23488142

  20. Continued development of a semianalytical solution for two-phase fluid and heat flow in a porous medium

    SciTech Connect

    Doughty, C.; Pruess, K. [Lawrence Berkeley Lab., CA (United States)

    1991-06-01

    Over the past few years the authors have developed a semianalytical solution for transient two-phase water, air, and heat flow in a porous medium surrounding a constant-strength linear heat source, using a similarity variable {eta} = r/{radical}t. Although the similarity transformation approach requires a simplified geometry, all the complex physical mechanisms involved in coupled two-phase fluid and heat flow can be taken into account in a rigorous way, so that the solution may be applied to a variety of problems of current interest. The work was motivated by adverse to predict the thermohydrological response to the proposed geologic repository for heat-generating high-level nuclear wastes at Yucca Mountain, Nevada, in a partially saturated, highly fractured volcanic formation. The paper describes thermal and hydrologic conditions near the heat source; new features of the model; vapor pressure lowering; and the effective-continuum representation of a fractured/porous medium.

  1. Modeling thermochemical heat storage in porous media with local thermal nonequilibrium - From constitutive theory to application

    NASA Astrophysics Data System (ADS)

    Nagel, T.; Shao, H.; Linder, M.; Wörner, A.; Kolditz, O.

    2013-12-01

    Heat processes in industry and for power generation can be made more cost-efficient and climate friendly by the integration of thermal energy storage devices. Due to high storage densities and superior long term storage characteristics, systems relying on thermochemical reactions are of great interest and often based on porous or granular media. As such, they share characteristic features in terms of mass and heat transport that are strongly coupled by physical and chemical phenomena. We have employed the theory of porous media to establish a model featuring reactive multicomponent compressible fluid mass transport through solid particle bed coupled to local thermal nonequilibrium heat transport. The model development has been based on an extensive evaluation of the Clausius-Duhem inequality to derive thermodynamically consistent constitutive relations for secondary variables as well as direct and indirect coupling terms. The model has then been implemented into the open source scientific simulation code OpenGeoSys using the finite element method. Lab and pilot scale thermochemical heat storage reactors with different reaction systems (oxidation reactions, hydration reactions) have been simulated successfully using axisymmetric geometries. The simulations show the strong coupling of pressure, concentration and temperature fields as well as the gas-solid reactions occurring inside the reactors. The effect of certain process parameters, such as mass flow and particle size, on the occurrence of local thermal nonequilibrium is illustrated. It is shown that the reactors can be used in a number of operating modes such as the extraction or release of heat accompanied by significant temperature drops or raises; the buffering or smoothing of temperature fluctuations at the inlet; the up- or downgrading of heat. The developed model therefore represents a useful tool to understand reactor behavior, optimize operating parameters, estimate thermal and parasitic losses, and dimension reactors depending on a specific application. Reaction rate during discharge of a thermochemical reactor. Red indicates areas with a high reaction rate, blue inactive regions.

  2. Diabatic heating rate estimates from European Centre for Medium-Range Weather Forecasts analyses

    NASA Technical Reports Server (NTRS)

    Christy, John R.

    1991-01-01

    Vertically integrated diabatic heating rate estimates (H) calculated from 32 months of European Center for Medium-Range Weather Forecasts daily analyses (May 1985-December 1987) are determined as residuals of the thermodynamic equation in pressure coordinates. Values for global, hemispheric, zonal, and grid point H are given as they vary over the time period examined. The distribution of H is compared with previous results and with outgoing longwave radiation (OLR) measurements. The most significant negative correlations between H and OLR occur for (1) tropical and Northern-Hemisphere mid-latitude oceanic areas and (2) zonal and hemispheric mean values for periods less than 90 days. Largest positive correlations are seen in periods greater than 90 days for the Northern Hemispheric mean and continental areas of North Africa, North America, northern Asia, and Antarctica. The physical basis for these relationships is discussed. An interyear comparison between 1986 and 1987 reveals the ENSO signal.

  3. Medium- and long-term storage of the Pycnanthemum (Mountain mint) germplasm collection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The US collection of mountain mint (Pycnanthemum Michx.) is held at the USDA-ARS National Clonal Germplasm Repository (NCGR) in Corvallis, OR as seed, potted plants and tissue cultures and a long-term storage collection is preserved at the USDA-ARS National Center for Genetic Resources Preservation ...

  4. Some thermophysical properties of paraffin wax as a thermal storage medium

    Microsoft Academic Search

    A. Haji-Sheikh; J. Eftekhar; D. Y. S. Lou

    1982-01-01

    An experimental study is conducted to determine the suitability of paraffin wax SUNTECH P116 as a phase change material for storage of thermal energy. Certain temperature dependent thermophysical properties in the neighborhood of the melting point useful for this study, but not adequately available in the literature, are measured. They include thermal conductivity, density, thermal expansion coefficient, and viscosity. It

  5. Research on solar energy storage subsystems utilizing the latent heat of phase change of paraffin hydrocarbons for the heating and cooling of buildings

    Microsoft Academic Search

    J. A. Bailey; J. C. Mulligan; C. K. Liao; S. I. Guceri

    1975-01-01

    An analytical and experimental research program designed to assess the potential of a solar energy storage subsystem (thermal capacitor) using the latent heat of fusion of paraffin hydrocarbons for the heating and cooling of buildings, is described. An idealized model of a flat plate thermal capacitor based on uniaxial heat conduction with a change of phase and an absence of

  6. Effect of Storage Temperature on Cultured Epidermal Cell Sheets Stored in Xenobiotic-Free Medium

    PubMed Central

    Jackson, Catherine; Aabel, Peder; Eidet, Jon R.; Messelt, Edward B.; Lyberg, Torstein; von Unge, Magnus; Utheim, Tor P.

    2014-01-01

    Cultured epidermal cell sheets (CECS) are used in regenerative medicine in patients with burns, and have potential to treat limbal stem cell deficiency (LSCD), as demonstrated in animal models. Despite widespread use, short-term storage options for CECS are limited. Advantages of storage include: flexibility in scheduling surgery, reserve sheets for repeat operations, more opportunity for quality control, and improved transportation to allow wider distribution. Studies on storage of CECS have thus far focused on cryopreservation, whereas refrigeration is a convenient method commonly used for whole skin graft storage in burns clinics. It has been shown that preservation of viable cells using these methods is variable. This study evaluated the effect of different temperatures spanning 4°C to 37°C, on the cell viability, morphology, proliferation and metabolic status of CECS stored over a two week period in a xenobiotic–free system. Compared to non-stored control, best cell viability was obtained at 24°C (95.2±9.9%); reduced cell viability, at approximately 60%, was demonstrated at several of the temperatures (12°C, 28°C, 32°C and 37°C). Metabolic activity was significantly higher between 24°C and 37°C, where glucose, lactate, lactate/glucose ratios, and oxygen tension indicated increased activation of the glycolytic pathway under aerobic conditions. Preservation of morphology as shown by phase contrast and scanning electron micrographs was best at 12°C and 16°C. PCNA immunocytochemistry indicated that only 12°C and 20°C allowed maintenance of proliferative function at a similar level to non-stored control. In conclusion, results indicate that 12°C and 24°C merit further investigation as the prospective optimum temperature for short-term storage of cultured epidermal cell sheets. PMID:25170754

  7. Heat transfer analysis of phase change process in a finned-tube thermal energy storage system using artificial neural network

    Microsoft Academic Search

    Kemal Ermis; Aytunc Erek; Ibrahim Dincer

    2007-01-01

    In this study, a feed-forward back-propagation artificial neural network (ANN) algorithm is proposed for heat transfer analysis of phase change process in a finned-tube, latent heat thermal energy storage system. Heat storage through phase change material (PCM) around the finned tube is experimentally studied. A numerical study is performed to investigate the effect of fin and flow parameter by the

  8. Design, Development of a Solar Chimney with Built-in Latent Heat Storage Material for Natural Ventilation

    Microsoft Academic Search

    S. D. Sharma; H. Kotani; Y. Kaneko; T. Yamanaka; K. Sagara

    2007-01-01

    A prototype of a solar chimney with a built-in latent heat storage system for prolonging ventilation system operation until evening\\/night or even 24 hours was designed and developed. Sodium Sulfate Decahydrate “Na2SO4.10H2O” (melting point 32°C, latent heat of fusion 126 kJ\\/kg) was used as a Phase Change Material (PCM) for latent heat storage. Experiments have been carried out with the

  9. Mixed-method pre-cooling reduces physiological demand without improving performance of medium-fast bowling in the heat

    Microsoft Academic Search

    Geoffrey M. Minett; Rob Duffield; Aaron Kellett; Marc Portus

    2012-01-01

    This study examined physiological and performance effects of pre-cooling on medium-fast bowling in the heat. Ten, medium-fast bowlers completed two randomised trials involving either cooling (mixed-methods) or control (no cooling) interventions before a 6-over bowling spell in 31.9±2.1°C and 63.5±9.3% relative humidity. Measures included bowling performance (ball speed, accuracy and run-up speeds), physical characteristics (global positioning system monitoring and counter-movement

  10. Economical Analysis of a Groundwater Source Heat Pump with Water Thermal Storage System

    E-print Network

    Zhou, Z.; Xu, W.; Li, J.; Zhao, J.; Niu, L.

    2006-01-01

    C HILLERS GWHP 15/30 C 12.2 C 12.2 C Fig. 2: The cooling and heating source system Tab.3 Initial investment comparison NO. Cost Items Scheme two (10,000RMB) Scheme one(10,000RMB) 1 Construction static section 1755.17 1506.84 1... storage system initial investment adds RMB2, 626,400. 4.2 Operating Cost Analysis Thermal Energy Storage system should calculate annual operating cost on the basis of load ratio and operating strategy. In the stage of design, in terms of annual...

  11. Influence of Heat Treatment and Veneering on the Storage Modulus and Surface of Zirconia Ceramic

    PubMed Central

    Siavikis, Georgius; Behr, Michael; van der Zel, Jef M; Feilzer, Albert J; Rosentritt, Martin

    2011-01-01

    Objectives: Glass-ceramic veneered zirconia is used for the application as fixed partial dentures. The aim of this investigation was to evaluate whether the heat treatment during veneering, the application of glass-ceramic for veneering or long term storage has an influence on the storage modulus of zirconia. Methods: Zirconia bars (Cercon, DeguDent, G; 0.5x2x20 mm) were fabricated and treated according to veneering conditions. Besides heating regimes between 680°C and 1000°C (liner bake and annealing), sandblasting (Al2O3) or steam cleaning were used. The bars were investigated after 90 days storage in water and acid. For investigating the influence of veneering, the bars were veneered in press- or layer technique. Dynamic mechanical analysis (DMA) in a three-point-bending design was performed to determine the storage modulus between 25°C and 200°C at a frequency of 1.66 Hz. All specimens were loaded on top and bottom (treatment on pressure or tensile stress side). Scanning electron microscopy (SEM) was used for evaluating the superficial changes of the zirconia surface due to treatment. Statistical analysis was performed using Mann Whitney U-test (?=0.05). Results: Sintered zirconia provided a storage modulus E’ of 215 (203/219) GPa and tan ? of 0.04 at 110°C. A 10%-decrease of E’ was found up to 180°C. The superficial appearance changed due to heating regime. Sandblasting reduced E’ to 213 GPa, heating influenced E’ between 205 GPa (liner bake 1) and 222 GPa (dentin bake 1). Steam cleaning, annealing and storage changed E’ between 4 GPa and 22 GPa, depending on the side of loading. After veneering, strong E’-reduction was found down to 84 GPa and 125 GPa. Conclusions: Veneering of zirconia with glass-ceramic in contrast to heat treating during veneering procedure had a strong influence on the modulus. The application of the glass-ceramic caused a stronger decrease of the storage modulus. PMID:21494388

  12. Attenuation thermal energy storage in sensible-heat solar-dynamic receivers

    NASA Astrophysics Data System (ADS)

    O'Ferrall Lund, Kurt

    Solar dynamic receiver designs are investigated and evaluated for possible use with sensible energy storage in single-phase materials. The designs are similar to previous receivers having axial distribution of concentrated solar input influx, but differ in utilizing axial conduction in the storage material for attenuation of the solar flux 'signal', and in having convective heat removal at the base of the receiver. One-dimensional, time-dependent heat transfer equations are formulated for the storage material temperature field, including radiative losses to the environment, and a general heat exchange effectiveness boundary condition at the base. The orbital periodic input solar flux is represented as the sum of steady and oscillating components, with the steady component solved numerically subject to specified receiver thermal efficiency. For the oscillating components the Fast Fourier Transform algorithm (FFT) is applied, and the complex transfer function of the receiver is obtained in the amplitudes and mode shapes of the oscillating temperatures. By adjustment of design parameters, the amplitude of the oscillating component of the outlet gas temperature is limited to an acceptable magnitude. The overall results of the investigation is the dependence of the receiver M-c product (mass times specific heat) on the conduction transfer units, which leads to lower weight designs than comparable previous single- and two-phase designs, when all constraints are included. As these attenuation designs also offer improvements in cost reduction and reliability they warrant further detailed investigation.

  13. Heating and ionization of the primordial intergalactic medium by high-mass X-ray binaries

    NASA Astrophysics Data System (ADS)

    Knevitt, G.; Wynn, G. A.; Power, C.; Bolton, J. S.

    2014-12-01

    We investigate the influence of high-mass X-ray binaries (HMXBs) on their high-redshift environments. Using a one-dimensional radiative transfer code, we predict the ionization and temperature profiles surrounding a coeval stellar population, composed of main-sequence stars and HMXBs, at various times after its formation. We consider both uniform density surroundings, and a cluster embedded in a 108 M? Navarro-Frenk-White (NFW) halo. HMXBs in a constant density environment produce negligible enhanced ionization because of their high-energy spectral energy distributions and short lifetimes. In this case, HMXBs only marginally contribute to the local heating rate. For NFW profiles, radiation from main-sequence stars cannot prevent the initially ionized volume from recombining since it is unable to penetrate the high-density galactic core. However, HMXB photons stall recombinations behind the front, keeping it partially ionized for longer. The increased electron density in these partially ionized regions promotes further cooling, resulting in lower intergalactic medium (IGM) temperatures. In the context of this starburst model, we have shown that HMXBs do not make a major contribution to reionization or IGM heating. However, X-ray escape fractions are high in both density profile cases. Continuous star formation may result in the build up of X-rays over time, reducing the ionization time-scale and potentially leading to low level ionization of the distant IGM.

  14. Heating medium absorption and emission as factors in thermographic investigations of petrochemical furnaces

    NASA Astrophysics Data System (ADS)

    Pregowski, P.; Goleniewski, G.; Komosa, W.; Korytkowski, W.; Zwolenik, Sl.

    2009-05-01

    This paper presents the current state of our efforts to increase efficiency of petrochemical plant with using spectral-band dynamic IR radiation thermometry. Depending on the type of investigations i.e. studying tubes' temperature, what is the most typical and important case or studying energetic and dynamic features of the flames and flue gases, different narrow-band optical filters and research procedures have to be applied. To perform both type of these measurements we modernized commercial PtSi FPA camera and software to process various sequences of thermal images. Two of results are highlighted: possibilities to increase tube' temperature measurements confident and reliability due to minimization of errors going from mostly fluctuating reflections of surrounding heat sources and self-emissions of heating medium between tube and camera, as well as a new diagnostic potential of the images of chosen gases features, for comparative investigations in particular. Case histories, some challenges and limitations during elaborated method application have also been addressed.

  15. An Experimental Study on Thermal Energy Storage Based Reverse Cycle Defrosting Method Using Subcooling Energy of Refrigerant for Air Source Heat Pump: Characteristics of Thermal Energy Storage Operation

    Microsoft Academic Search

    Dong Jiankai; Qu Minglu; Jiang Yiqiang; Yao Yang; Deng Shiming; Wang Honglei

    2011-01-01

    the introduction introduction of the the system of thermal energy storage torage (TES) based reverse cycle defrosting method using sub-cooling energy of refrigerant for air Source heat eat p pump (ASHP) is given firstly. And And then the the characteristic of TES TES using sub-cooling energy of refrigerant in in heating is experimentally researched. The results results show that that

  16. The medium is NOT the message or Indefinitely long-term file storage at Leeds University

    NASA Technical Reports Server (NTRS)

    Holdsworth, David

    1996-01-01

    Approximately 3 years ago we implemented an archive file storage system which embodies experiences gained over more than 25 years of using and writing file storage systems. It is the third in-house system that we have written, and all three systems have been adopted by other institutions. This paper discusses the requirements for long-term data storage in a university environment, and describes how our present system is designed to meet these requirements indefinitely. Particular emphasis is laid on experiences from past systems, and their influence on current system design. We also look at the influence of the IEEE-MSS standard. We currently have the system operating in five UK universities. The system operates in a multi-server environment, and is currently operational with UNIX (SunOS4, Solaris2, SGI-IRIX, HP-UX), NetWare3 and NetWare4. PCs logged on to NetWare can also archive and recover files that live on their hard disks.

  17. Heat Transfer Analysis of Encapsulated Phase Change Materials for Thermal Energy Storage

    NASA Astrophysics Data System (ADS)

    Elmozughi, Ali F.

    Thermal analysis of high temperature phase change materials (PCMs) is conducted. Transient two dimensional heat transfer analysis is performed to investigate high temperature energy storage and retrieval for concentrated solar power applications. The phase change materials are considered are NaNO 3 and the eutectic of MgCl2 and NaCl. Phase change material is encapsulated by a stainless steel in a cylindrical shaped capsule. Energy storage/retrieval into/from various sizes of encapsulated phase change material (EPCM) capsules is simulated for both laminar and turbulent flow conditions of the heat transfer fluid (HTF) by an accurate modeling of the propagating liquid/solid interface in a PCM. Heat transfer inside EPCM capsule and the phase change of PCM are modeled by an enthalpy - porosity method. A two-dimensional cylindrical shaped EPCM capsule or tube is considered in simulations using gas (air) and liquid (Therminol/VP-1) as heat transfer fluids in a cross flow and an axial flow arrangement. The energy storage/retrieval times into/out of the EPCM capsule is dictated by the surface heat transfer of the EPCM for the capsule sizes considered in this study. A single horizontally placed rod in a channel with different blockage ratios for laminar and turbulence flows of HTF is studied in the present study. It is illustrated by the present work that enthalpy-porosity method can be applied to simulate heat transfer at the capsule level and the system level. System level storage module is a thermocline that includes an arrangement of several EPCMs for several megawatts of thermal energy storage (TES) for several hours used in concentrated solar power applications and other industrial thermal systems. Transport phenomena inside the EPCM are modeled accurately by considering a 20% air void and the buoyancy-driven convection in a stainless steel capsule. The effects of the thermal expansion and the volume expansion due to phase change on the energy storage and retrieval process are investigated. The charging and discharging into and from the capsule wall is simulated for different boundary conditions and is applied with both laminar and turbulent flow conditions. Computational models are conducted by applying an enthalpy -- porosity method and volume of fluid method (VOF) to calculate the transport phenomena within the PCM capsule, including an internal air void. Energy storage and retrieval in different sized capsules is simulated. A cylindrical shaped EPCM capsule or tube is considered in simulations using both gas (air) and liquid (Therminol/VP-1) as the heat transfer fluid in a cross flow arrangement. The presence of the void has profound effects on the thermal response of the EPCM during both energy storage and retrieval process. Melting and solidification per unit mass of the PCM takes longer when the void is present. Additionally, due to material properties and the lack of convective effects, the solidification process is much slower than the melting process. One of the most significant outcomes of the present work is that the thermal energy module in the power generation systems has to be designed properly by careful consideration of the heat transfer from HTF to the EPCM as well as the heat transport inside the EPCM.

  18. Maintenance and storage of fuel oil for residential heating systems: A guide for residential heating system maintenance personnel

    SciTech Connect

    Litzke, Wai-Lin

    1992-12-01

    The quality of No. 2 fuel affects the performance of the heating system and is an important parameter in the proper and efficient operation of an oil-burning system. The physical and chemical characteristics of the fuel can affect the flow, atomization and combustion processes, all of which help to define and limit the overall performance of the heating system. The use of chemical additives by fuel oil marketershas become more common as a method of improving the quality of the fuel, especially for handling and storage. Numerous types of additives are available, but reliable information on their effectiveness and proper use is limited. This makes selecting an additive difficult in many situations. Common types of problems that contribute to poor fuel quality and how they affect residential heating equipment are identified inof this booklet. It covers the key items that are needed in an effective fuel quality monitoring program, such as what to look for when evaluating the quality of fuel as it is received from a supplier, or how to assess fuel problems associated with poor storage conditions. References to standard procedures and brief descriptions of the procedures also are given. Approaches for correcting a fuel-related problem, including the potential uses of chemical additives are discussed. Different types of additives are described to help users understand the functions and limitations of chemical treatment. Tips on how to select andeffectively use additives also are included. Finally, the importance of preventative maintenance in any fuel monitoring program is emphasized.

  19. High resolution numerical modelling of high temperature heat storage in geological media

    NASA Astrophysics Data System (ADS)

    Boockmeyer, Anke; Bauer, Sebastian

    2014-05-01

    Increasing use of energy stemming from renewable sources, such as wind or solar power plants, requires development of new and improvement of existing energy storage options on different time scales. One potential storage option is high temperature heat storage with temperatures of up to 100°C in the geological subsurface using borehole heat exchanger (BHE). Numerical scenario simulations are performed to assess feasibility and storage capacity and, furthermore, to predict the effects induced. To allow for accurate and reliable results, the BHE must be represented correctly and realistic in the numerical model. Therefore, a detailed model of a single BHE and the surrounding aquifer, accounting for the full geometry and component parametrisation (circulating working fluid, pipe and grout), is set up. This model setup is used to simulate an experimental data set from a laboratory sandbox by Beier et al. (2011), containing an 18 m long single U-tube BHE centered horizontally along it. Temperature curves observed in different radial distances as well as at the pipe outflow can be matched well with the model setup used, which is thus verified. Potential geological formations for high temperature heat storage are located in greater depths below fresh water aquifers that are used for drinking water. Therefore, the above model is adapted to represent a 100 m long vertical double U-tube BHE placed in an average depth of 500 m. The processes of heat transport and groundwater flow are coupled by water density and viscosity, which both depend on pressure and temperature. A sensitivity study is done to quantify the effects of the thermal parameters of grout and aquifer on the amount of heat stored and the temperature distribution in the aquifer. It was found that the amount of heat stored through the BHE is most sensitive to the heat conductivity of the aquifer. Increasing the aquifer heat conductivity by 50 % increases the amount of heat stored in the numerical model by 30 %. In contrast, only 3 % more heat can be stored in the system when increasing the grout thermal conductivity by 50 %. Temperature distribution in the aquifer is most sensitive to the thermal conductivity of the grout, resulting in higher temperatures when increasing the grout thermal conductivity. Increasing the aquifer thermal conductivity leads to higher temperatures at first and lower temperatures after a longer time period. Grout heat capacity, however, neither influences the amount of heat stored nor the temperature inside the aquifer. Occurrence and magnitude of the induced convection in the sand aquifer that surrounds the BHE depends on the given permeability as well as temperature gradients and therefore density differences in the model area. Increasing the vertical permeability from k=5×10-13 m2 to k=5×10-11 m2 results in induced convection with lower temperatures in the aquifer and a doubling of the amount of heat stored. Reference: R.A. Beier, M.D. Smith and J.D. Spitler. Reference data set for vertical borehole ground heat exchanger models and thermal response test analysis. Geothermics, 40, 79-85, (2011).

  20. Heating and cooling of a hospital using solar energy coupled with seasonal thermal energy storage in an aquifer

    Microsoft Academic Search

    H. O Paksoy; O Andersson; S Abaci; H Evliya; B Turgut

    2000-01-01

    A system is being designed, using solar energy in combination with Aquifer Thermal Energy Storage (ATES), that will conserve a major part of the oil and electricity used for heating or cooling the Cukurova University, Balcali Hospital in Adana, Turkey. The general objective of the system is to provide heating and cooling to the hospital by storing solar heat underground

  1. Measurement of the heat transfer rate for thermal energy storage masses in direct gain passive solar heating systems

    NASA Astrophysics Data System (ADS)

    Faunce, S. F.; Rickert, R. K.

    A way of measuring the heat transferred, as well as the amount of thermal energy stored in thermal mass used in a passive solar heating system, is described. A thermal flux meter measures the rate of heat transfer, and the data are recorded on a strip-chart recorder. This gives a time relationship for the solar energy absorbed and discharged by the mass. Integration of the area under the curve yields experimental data, which are related to the storage efficiency of the mass. The measurements are made using different orientations of the irradiated surface, which consists of different materials, such as brick, concrete, and phase change materials (Na2SO4-10H2O). Measurements for various mass composites made during December and January at Newark, Delaware (lat., 39.5 deg N), give values of heat transfer for absorption of the solar irradiated surface from 63 to 101 W/sq m for horizontally oriented masses and 158 to 212 W/sq m for the same masses in a vertical position. The discharge heat transfer rates due to convection are from 13 to 25 W/sq m for horizontal surfaces and 47 to 85 W/sq m for vertical surfaces.

  2. A Numerical Study of a Double Pipe Latent Heat Thermal Energy Storage System

    NASA Astrophysics Data System (ADS)

    Tabassum, Tonny

    Solar energy is an intermittent supply source of energy. To efficiently utilize this free renewable energy source some form of thermal energy storage devices are necessary. Phase change materials (PCMs), because of their high energy density storage capacity and near isothermal phase change characteristics, have proven to be promising candidates for latent heat thermal energy storage (LHTES) devices. Among the various LHTES devices for low temperature residential heating and cooling applications, the shell-and-tube type heat exchanging devices are the most simple to operate and can be easily fabricated. This work numerically investigates the buoyancy driven heat transfer process during melting (charging) of a commercial paraffin wax as PCM filling the annulus of a horizontal double pipe heat exchanger. The heated working fluid (water) is passing through the central tube of the annulus at a sufficiently high flow-rate and thereby maintaining an almost isothermal wall temperature at the inner pipe which is higher than the melting temperature of the PCM. The transient, two-dimensional coupled laminar momentum and energy equations for the model are suitably non-dimensionalized and are solved numerically using the enthalpy-porosity approach. Time-wise evolutions of the flow patterns and temperature distributions are presented through velocity vector fields and isotherm plots. In this study, two types of PCM filled annuli, a plain annulus and a strategically placed longitudinal finned annulus, are studied. The total energy stored, the total liquid fraction and the energy efficiency at different melting times are evaluated for three different operating conditions and the results are compared between the plain and finned annuli. The present study will provide guidelines for system thermal performance and design optimization of the shell-and-tube LHTES devices. .

  3. Estimated heats of fusion of fluoride salt mixtures suitable for thermal energy storage applications

    NASA Technical Reports Server (NTRS)

    Misra, A. K.; Whittenberger, J. D.

    1986-01-01

    The heats of fusion of several fluoride salt mixtures with melting points greater than 973 K were estimated from a coupled analysis of the available thermodynamic data and phase diagrams. Simple binary eutectic systems with and without terminal solid solutions, binary eutectics with congruent melting intermediate phases, and ternary eutectic systems were considered. Several combinations of salts were identified, most notable the eutectics LiF-22CaF2 and NaF-60MgF2 which melt at 1039 and 1273 K respectively which posses relatively high heats of fusion/gm (greater than 0.7 kJ/g). Such systems would seemingly be ideal candidates for the light weight, high energy storage media required by the thermal energy storage unit in advanced solar dynamic power systems envisioned for the future space missions.

  4. Radiation Heat Transfer Modeling Improved for Phase-Change, Thermal Energy Storage Systems

    NASA Technical Reports Server (NTRS)

    Kerslake, Thomas W.; Jacqmin, David A.

    1998-01-01

    Spacecraft solar dynamic power systems typically use high-temperature phase-change materials to efficiently store thermal energy for heat engine operation in orbital eclipse periods. Lithium fluoride salts are particularly well suited for this application because of their high heat of fusion, long-term stability, and appropriate melting point. Considerable attention has been focused on the development of thermal energy storage (TES) canisters that employ either pure lithium fluoride (LiF), with a melting point of 1121 K, or eutectic composition lithium-fluoride/calcium-difluoride (LiF-20CaF2), with a 1040 K melting point, as the phase-change material. Primary goals of TES canister development include maximizing the phase-change material melt fraction, minimizing the canister mass per unit of energy storage, and maximizing the phase-change material thermal charge/discharge rates within the limits posed by the container structure.

  5. Active heat exchange system development for latent heat thermal energy storage

    NASA Technical Reports Server (NTRS)

    Lefrois, R. T.; Mathur, A. K.

    1980-01-01

    Five tasks to select, design, fabricate, test and evaluate candidate active heat exchanger modules for future applications to solar and conventional utility power plants were discussed. Alternative mechanizations of active heat exchange concepts were analyzed for use with heat of fusion phase change materials (PCMs) in the temperature range of 250 to 350 C. Twenty-six heat exchange concepts were reviewed, and eight were selected for detailed assessment. Two candidates were selected for small-scale experimentation: a coated tube and shell heat exchanger and a direct contact reflux boiler. A dilute eutectic mixture of sodium nitrate and sodium hydroxide was selected as the PCM from over 50 candidate inorganic salt mixtures. Based on a salt screening process, eight major component salts were selected initially for further evaluation. The most attractive major components in the temperature range of 250 to 350 C appeared to be NaNO3, NaNO2, and NaOH. Sketches of the two active heat exchange concepts selected for test are given.

  6. Experimental analysis of regularly structured composite latent heat storages for temporary cooling of electronic components

    NASA Astrophysics Data System (ADS)

    Lohse, Ekkehard; Schmitz, Gerhard

    2013-11-01

    This study presents the experimental investigation of regularly structured Composite Latent Heat Storages. Solid-liquid Phase Change Materials have a low thermal conductivity, resulting in high temperature differences. This drawback is compensated by the combination with specially designed frame-structures made of aluminum to enhance the transport of thermal energy. A prototype is investigated experimentally on a test rig, where the heat load and temperatures are measured while the phase change process is observed optically, and compared to a solid block Phase Change Material.

  7. Yttrium-dispersed C60 fullerenes as high-capacity hydrogen storage medium.

    PubMed

    Tian, Zi-Ya; Dong, Shun-Le

    2014-02-28

    Interaction between hydrogen molecules and functionalized C60 is investigated using density functional theory method. Unlike transition metal atoms that tend to cluster on the surface, C60 decorated with 12 Yttrium atoms on each of its 12 pentagons is extremely stable and remarkably enhances the hydrogen adsorption capacity. Four H2 molecules can be chemisorbed on a single Y atom through well-known Dewar-Chatt-Duncanson interaction. The nature of bonding is a weak physisorption for the fifth adsorbed H2 molecule. Consequently, the C60Y12 complex with 60 hydrogen molecules has been demonstrated to lead to a hydrogen storage capacity of ?6.30 wt. %. PMID:24588190

  8. Yttrium-dispersed C60 fullerenes as high-capacity hydrogen storage medium

    NASA Astrophysics Data System (ADS)

    Tian, Zi-Ya; Dong, Shun-Le

    2014-02-01

    Interaction between hydrogen molecules and functionalized C60 is investigated using density functional theory method. Unlike transition metal atoms that tend to cluster on the surface, C60 decorated with 12 Yttrium atoms on each of its 12 pentagons is extremely stable and remarkably enhances the hydrogen adsorption capacity. Four H2 molecules can be chemisorbed on a single Y atom through well-known Dewar-Chatt-Duncanson interaction. The nature of bonding is a weak physisorption for the fifth adsorbed H2 molecule. Consequently, the C60Y12 complex with 60 hydrogen molecules has been demonstrated to lead to a hydrogen storage capacity of ˜6.30 wt. %.

  9. Optimized heat transfer fin design for a metal-hydride hydrogen storage container

    Microsoft Academic Search

    M. Melnichuk; N. Silin; H. A. Peretti

    2009-01-01

    This paper presents a heat transfer fin optimization for a LaNi5 hydrogen storage container. In this simplified approach, a one-dimension fin model is proposed in order to avoid geometrical restrictions and constrains associated to a particular technological solution. Therefore, the presented model can be utilized as a general framework for the development of containers with inner fins.The hydrogen absorption reaction

  10. Low cost solar energy heating system using aquifier energy storage for greenhouses

    Microsoft Academic Search

    W. J. Schaetzle; R. N. Bhattarai

    1981-01-01

    A low cost, solar-heating system for greenhouses has been investigated. A shallow pond collector using 4 x 4 lumber and polyethylene sheets is used for energy collection. The collectors can easily be constructed with material costs remaining under $0.25\\/ft². An aquifer is used for a large annual thermal energy storage system. The energy is primarily collected during the summer months

  11. Thermal Characteristics of Paraffin\\/Expanded Perlite Composite for Latent Heat Thermal Energy Storage

    Microsoft Academic Search

    A. Kara?pekl?; A. Sar?; K. Kaygusuz

    2009-01-01

    This study focuses on the preparation and thermal properties of paraffin\\/expanded perlite composite as novel form-stable phase change material for latent heat thermal energy storage by vacuum impregnation method. The paraffin could be absorbed in pores of expanded perlite as much as 55 wt% without melted phase change material seepage from the composite and this mixture was described as form-stable

  12. Numerical simulation of porous latent heat thermal energy storage for thermoelectric cooling

    Microsoft Academic Search

    Juan P. Trelles; John J. Dufly

    2003-01-01

    Porous latent heat thermal energy storage for thermoelectric cooling is simulated via a matrix-based enthalpy formulation, having the temperature as unknown, in a three-dimensional domain. The system is made up of two aluminum containers; the inner one contains the cooling objective in water suspension and the outer one the phase change material (PCM) in a porous aluminum matrix. The system’s

  13. Study of PV-Trombe wall installed in a fenestrated room with heat storage

    Microsoft Academic Search

    Ji Jie; Yi Hua; Pei Gang; Lu Jianping

    2007-01-01

    In this paper, a PV-Trombe wall (PV-TW) installed in a fenestrated room with heat storage is investigated to approach the practical application of PV-TW. Based on an updated mathematical model, theoretical simulation has been conducted for PV-TW in this case. Furthermore, field testing for this case has also been performed to validate the model, and then the simulated and experimental

  14. Efficacy of tertiary butylhydroquinone on the storage and heat stability of liquid canola shortening

    Microsoft Academic Search

    Z. J. Hawrysh; P. J. Shand; C. Lin; B. Tokarska; R. T. Hardin

    1990-01-01

    The sensory (odor and flavor) and physicochemical characteristics of tertiary butylhydroquinone (TBHQ) treated and butylated\\u000a hydroxyanisole\\/toluene (BHA\\/BHT) treated liquid canola shortenings, subjected to accelerated storage (Schaal oven test at\\u000a 65C) and deep fat heating (at 185C), were determined. Data for the Schaal oven test indicate that TBHQ was effective in\\u000a retarding oxidative rancidity in liquid canola shortenings. However, addition of

  15. Efficiency of a novel forensic room-temperature DNA storage medium.

    PubMed

    Frippiat, Christophe; Noel, Fabrice

    2014-03-01

    The success of forensic genetics has led to considerable numbers of DNA samples that must be stored. Thus, the ability to preserve the integrity of forensic samples is essential. The possibility of retesting these samples after many years should be guaranteed. DNA storage typically requires the use of freezers. Recently, a new method that enables DNA to be stored at room temperature was developed. This technology is based on the principles of anhydrobiosis and thus permits room-temperature storage of DNA. This study evaluates the ability of this technology to preserve DNA samples mimicking true mixture casework samples for long periods of time. Mixed human DNA from 2 or 3 persons and at low concentrations was dried and stored for a period ranging from 6 months to 2 years in the presence of a desiccant. The quality of the stored DNA was evaluated based on quantitative peak height results from Short Tandem Repeat (STR) genotyping and the number of observed alleles. Furthermore, we determined whether this matrix has a potential inhibitory or enhancing effect on the PCR genotyping reactions. In our previous work, we demonstrated the considerable potential of this new technology. The present study complements our previous work. Our results show that after 2 years of aging at room temperature, there is a decrease in the number of observed alleles and in the peak height of these alleles. PMID:24528585

  16. Soret and Dufour effects on natural convection heat and mass transfer from a vertical cone in a porous medium

    Microsoft Academic Search

    Ching-Yang Cheng

    2009-01-01

    This work studies the Soret and Dufour effects on the boundary layer flow due to natural convection heat and mass transfer over a downward-pointing vertical cone in a porous medium saturated with Newtonian fluids with constant wall temperature and concentration. A similarity analysis is performed, and the obtained similar equations are solved by cubic spline collocation method. The effects of

  17. Nonlinear two-dimensional potential based study of coupled heat and mass transfer in a porous medium

    Microsoft Academic Search

    S. M. Prabhu; Soundarajan Krishnan

    2006-01-01

    This paper deals with nonlinear analysis of coupled heat and mass transfer in a porous medium using a potential based model of the phenomenon. A numerical example is given to validate the model developed. The model is solved using a finite element scheme by simulation of experimental data. The hat and mass transfer are coupled phenomena studied in a wet

  18. Non-Darcy natural convection heat and mass transfer along a vertical permeable cylinder embedded in a porous medium

    Microsoft Academic Search

    M. A. Hossain; Kambiz Vafai; Khalil M. N. Khanafer

    1999-01-01

    Combined heat and mass transfer in non-Darcy natural convection flow along a permeable vertical cylinder embedded in a saturated porous medium is studied. The boundary layer analysis is formulated in terms of the combined thermal and solutal buoyancy effect. The flow field characteristics are analyzed using the implicit finite difference method as well as the local nonsimilarity method. The effect

  19. Analysis of coupled conduction and radiation heat transfer in presence of participating medium- using a hybrid method

    Microsoft Academic Search

    Sk Mahapatra; P. Nanda; A. Sarkar

    2005-01-01

    The current study addresses the mathematical modeling aspects of coupled conductive and radiative heat transfer in presence of absorbing, emitting and isotropic scattering gray medium within two-dimensional square enclosure. The walls of the enclosure are considered to be opaque, diffuse and gray. The enclosure comprised of isothermal vertical walls and insulated horizontal walls. A new hybrid method where the concepts

  20. Stability of thermal convection of an Oldroyd-B fluid in a porous medium with Newtonian heating

    Microsoft Academic Search

    Jun Niu; Ceji Fu; Wenchang Tan

    2010-01-01

    A linear stability analysis determining the onset of oscillatory convection of an Oldroyd-B fluid in a bounded two-dimensional rectangular porous medium generated by Newtonian heating is conducted. Influences of viscoelastic parameters and Biot number on the onset of oscillatory convection, preferred modes and patterns of disturbed temperature contours are discussed.

  1. Stability of thermal convection of an Oldroyd-B fluid in a porous medium with Newtonian heating

    NASA Astrophysics Data System (ADS)

    Niu, Jun; Fu, Ceji; Tan, Wenchang

    2010-10-01

    A linear stability analysis determining the onset of oscillatory convection of an Oldroyd-B fluid in a bounded two-dimensional rectangular porous medium generated by Newtonian heating is conducted. Influences of viscoelastic parameters and Biot number on the onset of oscillatory convection, preferred modes and patterns of disturbed temperature contours are discussed.

  2. Numerical simulation of heat exchange at a gas-solid medium flow past an evaporating semitransparent film

    NASA Astrophysics Data System (ADS)

    Rubtsov, N. A.; Sinitsyn, V. A.

    2014-12-01

    Numerical solution was obtained for the Stefan problem applied to non-stationary radiative-convective heat transfer during turbulent flow past a horizontal evaporating semitransparent melt film; the turbulent flow takes place for hot gas mixture carrying solid particles. The flowing film was heated intensively by radiation from an external heat source. Radiation passes through the gas-solid particle layer and the film and interacts with medium for a limited spectral interval. Simulation offers temperature fields and velocity fields for the boundary layer and the film. Simulation results are the basis for analysis of influence of radiation on dynamics of temperature fields and on the velocity of evaporation boundary.

  3. System for thermal energy storage, space heating and cooling and power conversion

    DOEpatents

    Gruen, Dieter M. (Downers Grove, IL); Fields, Paul R. (Chicago, IL)

    1981-04-21

    An integrated system for storing thermal energy, for space heating and cong and for power conversion is described which utilizes the reversible thermal decomposition characteristics of two hydrides having different decomposition pressures at the same temperature for energy storage and space conditioning and the expansion of high-pressure hydrogen for power conversion. The system consists of a plurality of reaction vessels, at least one containing each of the different hydrides, three loops of circulating heat transfer fluid which can be selectively coupled to the vessels for supplying the heat of decomposition from any appropriate source of thermal energy from the outside ambient environment or from the spaces to be cooled and for removing the heat of reaction to the outside ambient environment or to the spaces to be heated, and a hydrogen loop for directing the flow of hydrogen gas between the vessels. When used for power conversion, at least two vessels contain the same hydride and the hydrogen loop contains an expansion engine. The system is particularly suitable for the utilization of thermal energy supplied by solar collectors and concentrators, but may be used with any source of heat, including a source of low-grade heat.

  4. Heat storage and electricity generation in the Moon during the lunar night

    NASA Astrophysics Data System (ADS)

    Climent, Blai; Torroba, Oscar; González-Cinca, Ricard; Ramachandran, Narayanan; Griffin, Michael D.

    2014-01-01

    One of the biggest challenges of the exploration of the Moon is the survival of the crew and the lunar assets during the lunar night. The environmental conditions on the lunar surface and its cycle, with long periods of darkness, make any long mission in need of specific amounts of heat and electricity to be successful. We have analyzed two different systems to produce heat and electricity on the Moon's surface. The first system consists of Thermal Wadis, sources of thermal power that can be used to supply heat to protect the exploration systems from the extreme cold during periods of darkness. Previous results showed that Wadis can supply enough heat to keep lunar devices such as rovers above their minimum operating temperature (approximately 243 K). The second system studied here is the Thermal Energy Storage (TES), which is able to run a heat engine during the lunar night to produce electricity. When the Sun is shining on the Moon's surface, the system can run the engine directly using the solar power and simultaneously heat a thermal mass. This thermal mass is used as a high temperature source to run the heat engine during the night. We present analytical and numerical calculations for the determination of an appropriate thermal mass for the TES system.

  5. Effect of heat treatment on the storage stability of low calorie milk drinks.

    PubMed

    Mittal, Shikha; Bajwa, Usha

    2014-09-01

    The study was undertaken to study the effect of heat treatment on the storage stability of cardamom flavoured low calorie milk drinks (CFDs). The drinks prepared by replacing sugar with sucralose and adding inulin in milk of 0.5 % fat and 8.5 % milk solid-not-fat were subjected to pasteurization and sterilization and stored at refrigeration and room temperature, respectively. The stored samples were evaluated for changes in physico-chemical and sensory attributes at regular intervals. In pasteurized drinks, the total solids (TS) and pH declined while the total soluble solids (TSS), titratable acidity and viscosity increased significantly (p?storage. A significant reduction in the flavour and body and mouthfeel scores was observed. Standard plate count (SPC) increased in both control and low calorie drinks with storage period. In sterilized CFDs, TS and TSS were not affected appreciably whereas titratable acidity increased and viscosity decreased significantly (p?storage. Though the sensory scores also declined with storage, the drinks obtained high acceptability scores even after 150 days of storage at room temperature. However, the changes in colour components (L, a and b values) indicated increased browning in the drinks with storage time. SPC was not detected until 120 days in control and 135 days in low calorie drink. Yeast and molds were not evident until 135 days in control and 150 days in low calorie drink. The shelf life was found to be 10 and 150 days of pasteurized and sterilized CFDs at refrigeration and room temperature, respectively. PMID:25190842

  6. Gas hydrate cool storage system

    DOEpatents

    Ternes, M.P.; Kedl, R.J.

    1984-09-12

    The invention presented relates to the development of a process utilizing a gas hydrate as a cool storage medium for alleviating electric load demands during peak usage periods. Several objectives of the invention are mentioned concerning the formation of the gas hydrate as storage material in a thermal energy storage system within a heat pump cycle system. The gas hydrate was formed using a refrigerant in water and an example with R-12 refrigerant is included. (BCS)

  7. Solar passive ceiling system. Final report. [Passive solar heating system with venetian blind reflectors and latent heat storage in ceiling

    SciTech Connect

    Schneider, A.R.

    1980-01-01

    The construction of a 1200 square foot building, with full basement, built to be used as a branch library in a rural area is described. The primary heating source is a passive solar system consisting of a south facing window system. The system consists of: a set of windows located in the south facing wall only, composed of double glazed units; a set of reflectors mounted in each window which reflects sunlight up to the ceiling (the reflectors are similar to venetian blinds); a storage area in the ceiling which absorbs the heat from the reflected sunlight and stores it in foil salt pouches laid in the ceiling; and an automated curtain which automatically covers and uncovers the south facing window system. The system is totally passive and uses no blowers, pumps or other active types of heat distribution equipment. The building contains a basement which is normally not heated, and the north facing wall is bermed four feet high around the north side.

  8. The Effect of Porous Medium Storage on Unstable Density-Driven Solute Transport.

    PubMed

    Xie, Yueqing; Graf, Thomas; Simmons, Craig T; Diersch, Hans-Jörg G

    2014-11-13

    Unstable density-driven groundwater flow and solute transport (i.e., free convection) leads to spatiotemporal variations in pressure. Specific storage (So ) indicates the capability of a confined aquifer to release or store groundwater associated with a pressure change. Although So is known to dampen pressure propagation, So has been implicitly assumed to have a negligible impact on the unstable free convective process in prior studies. This work explores the effect of So on both the classic onset criterion and the fingering process using numerical models. Results show that the classic onset criterion is applicable when So is smaller than 10(-1) ?m(-1) . Results also demonstrate that So does not play a significant role in the free convective fingering process unless it is greater than 10(-3) ?m(-1) . For most practical purposes in hydrogeology (large Rayleigh number and small So ), the implicit assumption of small or zero So is appropriate. PMID:25393965

  9. Yttrium-dispersed C{sub 60} fullerenes as high-capacity hydrogen storage medium

    SciTech Connect

    Tian, Zi-Ya; Dong, Shun-Le, E-mail: dongshunle2013@hotmail.com [Department of Physics, Ocean University of China, Qingdao 266100 (China)] [Department of Physics, Ocean University of China, Qingdao 266100 (China)

    2014-02-28

    Interaction between hydrogen molecules and functionalized C{sub 60} is investigated using density functional theory method. Unlike transition metal atoms that tend to cluster on the surface, C{sub 60} decorated with 12 Yttrium atoms on each of its 12 pentagons is extremely stable and remarkably enhances the hydrogen adsorption capacity. Four H{sub 2} molecules can be chemisorbed on a single Y atom through well-known Dewar-Chatt-Duncanson interaction. The nature of bonding is a weak physisorption for the fifth adsorbed H{sub 2} molecule. Consequently, the C{sub 60}Y{sub 12} complex with 60 hydrogen molecules has been demonstrated to lead to a hydrogen storage capacity of ?6.30 wt. %.

  10. 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)

  11. Assessment and Prediction of the Thermal Performance of a Centralized Latent Heat Thermal Energy Storage Utilizing Artificial Neural Network

    E-print Network

    El-Sawi, A.; Haghighat, F.; Akbari, H.

    2013-01-01

    A simulation tool is developed to analyze the thermal performance of a centralized latent heat thermal energy storage system (LHTES) using computational fluid dynamics (CFD). The LHTES system is integrated with a mechanical ventilation system...

  12. Effect of porosity and the inlet heat transfer fluid temperature variation on the performance of cool thermal energy storage system

    Microsoft Academic Search

    M. Cheralathan; R. Velraj; S. Renganarayanan

    2007-01-01

    This paper discusses the results of numerical and experimental study of an encapsulated cool thermal energy storage system.\\u000a The storage system is a cylindrical storage tank filled with phase change material encapsulated in spherical container, placed\\u000a in a refrigeration loop. A simulation program was developed to evaluate the temperature histories of the heat transfer fluid\\u000a and the phase change material

  13. Characteristics of heat transfer from the working medium to the case of an axial-flow compressor

    NASA Astrophysics Data System (ADS)

    Lokai, V. I.; Karimova, A. G.; Prokopev, V. I.

    The heat transfer from the working medium to the case of an axial-flow compressor is investigated experimentally over a wide range of rpm (7000-17,000), air flow rates, and radial clearances between the case and the rotor. A nonuniform distribution of heat transfer coefficients over different parts of the case is observed for all the operating conditions investigated. Maximum heat transfer coefficients have been measured over the rotor near the exit; somewhat lower heat transfer coefficients have been recorded in the radial clearance behind the rotor; and still lower heat transfer coefficients have been observed at the ends of the interblade channels of the guide vanes and in the radial clearance behind them.

  14. Heat transfer in a high-temperature packed bed thermal energy storage system -- Roles of radiation and intraparticle conduction

    Microsoft Academic Search

    A. A. Jalalzadeh-Azar; W. G. Steele; G. A. Adebiyi

    1996-01-01

    A model is developed and experimentally verified to study the heat transfer in a high-temperature packed bed thermal energy storage system utilizing zirconium oxide pellets. The packed bed receives flue gas at elevated temperatures varying with time during the storage process and utilizes air for the recovery process. Both convection and radiation are included in the model of the total

  15. Enhancement of solar thermal energy storage performance using sodium thiosulfate pentahydrate of a conventional solar water-heating system

    Microsoft Academic Search

    Suat Canbazo?lu; Abdulmuttalip ?ahinaslan; Ahmet Ekmekyapar; Ý. Gökhan Aksoy; Fatih Akarsu

    2005-01-01

    The time variations of the water temperatures at the midpoint of the heat storage tank and at the outlet of the collector in a conventional open-loop passive solar water-heating system combined with sodium thiosulfate pentahydrate-phase change material (PCM) were experimentally investigated during November and then enhancement of solar thermal energy storage performance of the system by comparing with those of

  16. Numerical Simulation of Thermal Energy Storage in Underground Soil Heat Accumulator

    NASA Astrophysics Data System (ADS)

    Kortiš, Ján; Gottwald, Michal

    2014-12-01

    The alternative energy sources have been getting popular for last decades as a new way to obtain enough energy especially for countries which do not have rich natural reservoirs of fossil fuels. Gathering the thermal energy from the solar radiation seems to be as one of the cheapest alternatives of them. The disadvantage of it is the overflow of the heat energy during the summer and lack of them during the winter, when the demand for heat is on top. The underground thermal energy storage can be a good alternative for accumulating the heat energy and then offers it on demand. However, it is difficult to monitor the real physical condition in the soil. In the article, the results of numerical simulation are shown as a good way for a better identification of the process of accumulating the energy to the soil material.

  17. Retrospective dosimetry: dose evaluation using unheated and heated quartz from a radioactive waste storage building.

    PubMed

    Jain, M; Bøtter-Jensen, L; Murray, A S; Jungner, H

    2002-01-01

    In the assessment of dose received from a nuclear accident, considerable attention has been paid to retrospective dosimetry using heated materials such as household ceramics and bricks. However, unheated materials such as mortar and concrete are more commonly found in industrial sites and particularly in nuclear installations. These materials contain natural dosemeters such as quartz, which usually is less sensitive than its heated counterpart. The potential of quartz extracted from mortar in a wall of a low-level radioactive-waste storage facility containing distributed sources of 60Co and 137Cs has been investigated. Dose-depth proliles based on small aliquots and single grains from the quartz extracted from the mortar samples are reported here. These are compared with results from heated quartz and polymineral fine grains extracted from an adjacent brick, and the integrated dose recorded by environmental TLDs. PMID:12382805

  18. Performance of a day\\/night water heat storage system for heating and cooling of semi-closed greenhouses in mild winter climate

    Microsoft Academic Search

    E. J. Baeza; J. J. Pérez Parra; J. C. López; J. C. Gázquez; D. E. Meca; C. Stanghellini; F. L. K. Kempkes; J. I. Montero

    2012-01-01

    A novel system for heating\\/cooling greenhouses based on air\\/water heat exchangers connected to a thermally stratified water storage tank was tested in a small greenhouse compartment at the Experimental Station of the Cajamar Foundation in Almería, Spain. The system maintained a closed greenhouse (no natural ventilation) throughout the winter and spring during which a truss tomato crop was grown. Atmospheric

  19. Accumulation of plant small heat-stress proteins in storage organs.

    PubMed

    Lubaretz, Olga; Zur Nieden, Uta

    2002-06-01

    Plant small heat-stress proteins (sHSPs) have been shown to be expressed not only after exposure to elevated temperatures, but also at particular developmental stages such as embryogenesis, microsporogenesis, and fruit maturation. This paper presents new data on the occurrence of sHSPs in vegetative tissues, their tissue-specific distribution, and cellular localization. We have found sHSPs in 1-year-old twigs of Acer platanoides L. and Sambucus nigra L. and in the liana Aristolochia macrophylla Lamk. exclusively in the winter months. In tendrils of Aristolochia, sHSPs were localized in vascular cambium cells. After budding, in spring, these proteins were no longer present. Furthermore, accumulation of sHSPs was demonstrated in tubers and bulbs of Allium cepa L., Amaryllis ( Hippeastrum hybridum hort.), Crocus albiflorus L., Hyacinthus orientalis L., Narcissus pseudonarcissus L., Tulipa gesneriana L., and Solanum tuberosum L. (potato). In potato tubers and bulb scales of Narcissus the stress proteins were localized in the central vacuoles of storage parenchyma cells. In order to obtain more information on a possible functional correlation between storage proteins and sHSPs, the accumulation of both types of protein in tobacco seeds during seed ripening and germination was monitored. The expression of sHSPs and globulins started simultaneously at about the 17th day after anthesis. During seed germination the sHSPs disappeared in parallel with the storage proteins. Furthermore, in embryos of transgenic tobacco plants, which do not contain any protein bodies or storage proteins, no sHSPs were found. Thus, the occurrence of sHSPs in perennial plant storage organs seems to be associated with the presence of storage proteins. PMID:12029471

  20. Underground natural gas storage in the United States 1979 - 1980 heating year

    NASA Astrophysics Data System (ADS)

    1980-09-01

    Total gas in storage in the nation's active underground natural gas storage reservoirs as of March 31, 1980, the end of the 1979-1980 heating year, was reported at 5,129 billion cubic feet. Of this total, approximately 69.1 percent was base, or cushion, gas and 30.9 percent was working gas. Working gas totaled 1,586 billion cubic feet, approximately 28.2 percent above that available at the beginning of the heating year. The nation's 383 active storage reservoirs were operated by 77 companies. Total reservoir capacity was reported at 7,287 billion cubic feet, approximately 51.4 percent, or 3,744 billion cubic feet of which was working gas capacity. Approximately 67.9 percent of this working gas capacity was in 228 reservoirs operated by 30 interstate pipeline companies, 29.1 percent was in 142 reservoirs operated by 42 intrastate companies, and 3.1 percent was in 13 reservoirs operated by 5 independent producers.

  1. Heat storage and anthropogenic heat flux in relation to the energy balance of a central European city centre

    NASA Astrophysics Data System (ADS)

    Offerle, B.; Grimmond, C. S. B.; Fortuniak, K.

    2005-08-01

    The role of net heat storage QS and anthropogenic heat QF are considered in the surface energy balance for a downtown area in ód, Poland, for a 2 year period. Eddy covariance measurements provide estimates of the turbulent heat fluxes and radiometric measurements of the net all-wave radiation. A method to determine QS based on representative surface temperature sampling is employed and compared with results from two other models. Results show that QS is an important flux on the scale of hours to days and that it can be more than 10 W m-2, on average, for periods of a week or more. By incorporating QS estimates over hourly intervals, QF was then determined as the residual of the energy balance. Using the approach, QF averaged 32 W m-2 from October to March (60% of available energy), and -3 W m-2 from June to August. The physically unrealistic negative values for the summer period may suggest underestimation of turbulent fluxes, but no causal factor was identified. Although energy balance closure was close to 100% throughout the year, there was weaker agreement in the winter. This is attributed to errors in estimates of QS and variation in QF. Results highlight the need for future investigations of the urban surface energy balance to incorporate more complete measurements and estimates of QS.

  2. An Example:-Control of Blood Glucose Glucose in Body Cells is Stored in Medium-Term Storage (Fat, Long-Term; ATP and

    E-print Network

    Cutler, Chris

    (by Pancreatic Beta Cells) to Lower Blood Glucose to a Normal Level After Meals When Blood Glucose-Term) __________________________ (Adrenaline) Also Causes an Increase in Blood Glucose Levels This Provides ______________ to DealAn Example:- Control of Blood Glucose Glucose in Body Cells is Stored in Medium-Term Storage (Fat

  3. Thermal analysis of heat storage canisters for a solar dynamic, space power system

    NASA Technical Reports Server (NTRS)

    Wichner, R. P.; Solomon, A. D.; Drake, J. B.; Williams, P. T.

    1988-01-01

    A thermal analysis was performed of a thermal energy storage canister of a type suggested for use in a solar receiver for an orbiting Brayton cycle power system. Energy storage for the eclipse portion of the cycle is provided by the latent heat of a eutectic mixture of LiF and CaF2 contained in the canister. The chief motivation for the study is the prediction of vapor void effects on temperature profiles and the identification of possible differences between ground test data and projected behavior in microgravity. The first phase of this study is based on a two-dimensional, cylindrical coordinates model using an interim procedure for describing void behavor in 1-g and microgravity. The thermal analysis includes the effects of solidification front behavior, conduction in liquid/solid salt and canister materials, void growth and shrinkage, radiant heat transfer across the void, and convection in the melt due to Marangoni-induced flow and, in 1-g, flow due to density gradients. A number of significant differences between 1-g and o-g behavior were found. This resulted from differences in void location relative to the maximum heat flux and a significantly smaller effective conductance in 0-g due to the absence of gravity-induced convection.

  4. Automatic control of electric thermal storage (heat) under real-time pricing. Final report

    SciTech Connect

    Daryanian, B.; Tabors, R.D.; Bohn, R.E. [Tabors Caramanis and Associates, Inc. (United States)

    1995-01-01

    Real-time pricing (RTP) can be used by electric utilities as a control signal for responsive demand-side management (DSM) programs. Electric thermal storage (ETS) systems in buildings provide the inherent flexibility needed to take advantage of variations in prices. Under RTP, optimal performance for ETS operations is achieved under market conditions where reductions in customers` costs coincide with the lowering of the cost of service for electric utilities. The RTP signal conveys the time-varying actual marginal cost of the electric service to customers. The RTP rate is a combination of various cost components, including marginal generation fuel and maintenance costs, marginal costs of transmission and distribution losses, and marginal quality of supply and transmission costs. This report describes the results of an experiment in automatic control of heat storage systems under RTP during the winter seasons of 1989--90 and 1990--91.

  5. One-Step Quenching and Partitioning Heat Treatment of Medium Carbon Low Alloy Steel

    NASA Astrophysics Data System (ADS)

    Tariq, Fawad; Baloch, Rasheed Ahmed

    2014-05-01

    This paper presents the results of novel one-step quenching and partitioning (Q&P) heat treatment conducted on medium carbon low alloy steel sheet. Samples were austenitised at 1193 K followed by interrupted quenching at 473 K for different partitioning times and finally they were quenched in water. Dilatometry was employed for selection of treatment temperatures. Optical and scanning electron microscopy was carried out to examine the microstructural changes. Volume fraction of retained austenite was measured by x-ray diffraction technique. Resulting microstructures were correlated with the mechanical properties such hardness, tensile strength, elongation, impact absorbed energy, etc. The notch tensile and fracture toughness properties of Q&P steels are still lacking therefore notch tensile strength and plain strain fracture toughness tests were conducted and results are reported here. Results of Q&P treatments were also compared with the properties obtained by conventional Quenching and Tempering (Q&T) and normalizing treatments. Optimum strength-ductility balance of about 2000 MPa tensile strength with 11% elongation was achieved in samples quenched at 473 K and isothermally partitioned for 100 s. Higher ductility of Q&P steel was attributed to the presence of 6.8% film-type interlath retained austenite. Fine-grained martensitic structure with high density of interphase boundaries imparted ultrahigh strength. It was further noted that the impact toughness, notch tensile strength and fracture toughness of 1000 s partitioned samples was higher than 100 s partitioned samples. Possible reasons for high toughness are synergetic effect of recovery of dislocations, partial loss of martensite tetragonality and precipitation of fine transition carbides.

  6. Perpendicular magnetization reversal mechanism of functional FePt films for magnetic storage medium

    NASA Astrophysics Data System (ADS)

    Wei, Da-Hua; Chi, Po-Wei; Chao, Chung-Hua

    2014-11-01

    Magnetization reversal mechanism and related surface morphology of functional FePt(001) alloy films with large perpendicular magnetic anisotropy have been explored by alternate-atomic-layer deposition onto Pt/MgO(100) substrates via electron beam evaporation, and all evaporated films have been kept at in-situ substrate heating temperature of 400 °C. The FePt alloy film was composed of ultrathin [Fe (0.5 nm)/Pt (0.5 nm)]n Fe/Pt multilayer structures. The corresponding thickness of multilayer films was controlled by the periodic bilayer numbers (n) and varied in the range from 15 nm (n = 15) to 30 nm (n = 30). The surface topography was observed and varied from granular-like island to continuous microstructures with increasing the periodic numbers of Fe/Pt bilayer films. The measurement of angular dependent coercivity showed a tendency of the near rotation of reverse-domain type (n = 15) shift towards the domain-wall motion as a typical peak behavior (n = 30) with increasing the periodic bilayer numbers of Fe/Pt multilayers. On the basis of all magnetic measurements and corresponding magnetization analysis, indicating that the perpendicular magnetization reversal mechanism and related surface morphology of ordered FePt(001) alloy films could be systematically controlled by varying the periodic bilayer numbers accompanied with the thickness dependence.

  7. Effect of Heat and Electricity Storage and Reliability on Microgrid Viability:A Study of Commercial Buildings in California and New York States

    SciTech Connect

    Stadler, Michael; Marnay, Chris; Siddiqui, Afzal; Lai, Judy; Coffey, Brian; Aki, Hirohisa

    2008-12-01

    In past work, Berkeley Lab has developed the Distributed Energy Resources Customer Adoption Model (DER-CAM). Given end-use energy details for a facility, a description of its economic environment and a menu of available equipment, DER-CAM finds the optimal investment portfolio and its operating schedule which together minimize the cost of meeting site service, e.g., cooling, heating, requirements. Past studies have considered combined heat and power (CHP) technologies. Methods and software have been developed to solve this problem, finding optimal solutions which take simultaneity into account. This project aims to extend on those prior capabilities in two key dimensions. In this research storage technologies have been added as well as power quality and reliability (PQR) features that provide the ability to value the additional indirect reliability benefit derived from Consortium for Electricity Reliability Technology Solutions (CERTS) Microgrid capability. This project is intended to determine how attractive on-site generation becomes to a medium-sized commercial site if economical storage (both electrical and thermal), CHP opportunities, and PQR benefits are provided in addition to avoiding electricity purchases. On-site electrical storage, generators, and the ability to seamlessly connect and disconnect from utility service would provide the facility with ride-through capability for minor grid disturbances. Three building types in both California and New York are assumed to have a share of their sensitive electrical load separable. Providing enhanced service to this load fraction has an unknown value to the facility, which is estimated analytically. In summary, this project began with 3 major goals: (1) to conduct detailed analysis to find the optimal equipment combination for microgrids at a few promising commercial building hosts in the two favorable markets of California and New York; (2) to extend the analysis capability of DER-CAM to include both heat and electricity storage; and (3) to make an initial effort towards adding consideration of PQR into the capabilities of DER-CAM.

  8. Inorganic compounds for passive solar energy storage: Solid-state dehydration materials and high specific heat materials

    NASA Astrophysics Data System (ADS)

    Struble, L. J.; Brown, P. W.

    1986-04-01

    Two classes of hydrated inorganic salts have been studied to assess their potential as materials for passive solar energy storage. The materials are part of the quaternary system CaO-Al2O3-SO3-H2O and related chemical systems, and the two classes are typified by ettringite, a trisubstituted salt, and Friedel's salt, a monosubstituted salt. The trisubstituted salts were studied for their possible application in latent heat storage, utilizing a low-temperature dehydration reaction, and both classes were studies for their application in sensible heat storage. In order to assess their potential for energy storage, the salts have been synthesized, characterized by several analytical techniques, and thermal properties measured. The dehydration data of that the trisubstituted salts vary somewhat with chemical composition, with the temperature of the onset of dehydration ranging from 6(0)C to 33(0)C, and enthalpy changes on dehydration ranging from 60 to 200 cal/g. Heat capacity is less variable with composition; values for the trisubstituted phases are 30 cal/g/(0)C and for the monosubstituted phases between 0.23 and 0.28 cal/g/(0)C. Preliminary experiments indicate that the dehydration is reversible, and suggest that the materials might have additional potential as solar desiccant materials. These thermal data demonstrate the trisubstituted salts have potential as latent heat storage materials, and that both classes of salts have potential as sensible heat storage materials.

  9. Effect of Heating Treatments, Processing Methods and Refrigerated Storage of Milk and Some Dairy Products on Lipids Oxidation

    Microsoft Academic Search

    2008-01-01

    The effect of heating treatments (pasteurization and boiling), micro waving, processing steps and storage of milk and some locally produced dairy products (Brined white cheese (Nabulsi), Yogurt and Labaneh on chemical changes of milk lipids were evaluated. The Peroxide value (POV) p-anisidine value (p-AV), thiobarbituric acid (TBA), free fatty acid and totox were determined. The heating treatments of milk do

  10. 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.

  11. Two-dimensional nonlinear heat conduction wave in a layer-inhomogeneous medium and the characteristics of heat transfer in laser thermonuclear fusion targets

    SciTech Connect

    Gus'kov, Sergei Yu; Doskach, I Ya [P.N. Lebedev Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation)

    1999-10-31

    An analytical solution is obtained to the problem of propagation of a 2-D nonlinear heat conduction wave from a cylindrical energy source, which acts in a planar layer of a material surrounded by a medium with different mass density and degree of ionisation. A theoretical justification is given of several interesting phenomena of 2-D thermal wave propagation through an inhomogeneous medium. These phenomena are related to the difference between the thermal wave velocities in the media with different thermal diffusivities. When the mass density in a layer experiencing the action of an energy source exceeds the density of the surrounding medium, the thermal wave front is shown to glide along the layer boundaries with a spatial velocity exceeding the velocity of the wave inside the layer. Moreover, there is a possibility of 'themal flow' of a layer across the boundaries between the layer and the surrounding medium in front of a thermal wave propagating inside the layer. The problems of heat transfer in multilayer targets for laser thermonuclear fusion are considered as an application. (interaction of laser radiation with matter. laser plasma)

  12. The integration of water loop heat pump and building structural thermal storage systems

    SciTech Connect

    Marseille, T.J.; Schliesing, J.S.

    1991-10-01

    Many commercial buildings need heat in one part and, at the same time, cooling in another part. Even more common is the need for heating during one part of the day and cooling during another in the same spaces. If that energy could be shifted or stored for later use, significant energy might be saved. If a building's heating and cooling subsystems could be integrated with the building's structural mass and used to collect, store, and deliver energy, the energy might be save cost-effectively. To explore this opportunity, researchers at the Pacific Northwest Laboratory (PNL) examined the thermal interactions between the heating, ventilating, and air-conditioning (HVAC) system and the structure of a commercial building. Computer models were developed to simulate the interactions in an existing building located in Seattle, Washington, to determine how these building subsystems could be integrated to improve energy efficiency. The HVAC subsystems in the existing building were modeled. These subsystems consist of decentralized water-source heat pumps (WSHP) in a closed water loop, connected to cooling towers for heat rejection during cooling mode and boilers to augment heating. An initial base case'' computer model of the Seattle building, as-built, was developed. Metered data available for the building were used to calibrate this model to ensure that the analysis would provide information that closely reflected the operation of a real building. The HVAC system and building structure were integrated in the model using the concrete floor slabs as thermal storage media. The slabs may be actively charged during off-peak periods with the chilled water in the loop and then either actively or passively discharged into the conditioned space during peak periods. 21 refs., 37 figs., 17 tabs.

  13. Computational modeling of biomagnetic micropolar blood flow and heat transfer in a two-dimensional non-Darcian porous medium

    Microsoft Academic Search

    O. Anwar Bég; R. Bhargava; S. Rawat; Kalim Halim; H. S. Takhar

    2008-01-01

    We study theoretically and computationally the incompressible, non-conducting, micropolar, biomagnetic (blood) flow and heat\\u000a transfer through a two-dimensional square porous medium in an (x,y) coordinate system, bound by impermeable walls. The magnetic field acting on the fluid is generated by an electrical current\\u000a flowing normal to the x–y plane, at a distance l beneath the base side of the square.

  14. Thermal energy storage material thermophysical property measurement and heat transfer impact

    NASA Technical Reports Server (NTRS)

    Tye, R. P.; Bourne, J. G.; Destarlais, A. O.

    1976-01-01

    The thermophysical properties of salts having potential for thermal energy storage to provide peaking energy in conventional electric utility power plants were investigated. The power plants studied were the pressurized water reactor, boiling water reactor, supercritical steam reactor, and high temperature gas reactor. The salts considered were LiNO3, 63LiOH/37 LiCl eutectic, LiOH, and Na2B4O7. The thermal conductivity, specific heat (including latent heat of fusion), and density of each salt were measured for a temperature range of at least + or - 100 K of the measured melting point. Measurements were made with both reagent and commercial grades of each salt.

  15. Second law optimization of a sensible heat thermal energy storage system with a distributed storage element. Part 2; Presentation and interpretation of results

    Microsoft Academic Search

    M. J. Taylor; R. J. Krane; J. R. Parsons

    1991-01-01

    This paper explores the behavior of a flat- slab, sensible heat thermal energy storage system, the physical design and operation of which have been optimized to minimize the production of entropy by thermodynamic irreversibilities. This part includes a description of the numerical model and the presentation and interpretation of the results of a system optimization study. The major results of

  16. Parametric Analysis of Cyclic Phase Change and Energy Storage in Solar Heat Receivers

    NASA Technical Reports Server (NTRS)

    Hall, Carsie A., III; Glakpe, Emmanuel K.; Cannon, Joseph N.; Kerslake, Thomas W.

    1997-01-01

    A parametric study on cyclic melting and freezing of an encapsulated phase change material (PCM), integrated into a solar heat receiver, has been performed. The cyclic nature of the present melt/freeze problem is relevant to latent heat thermal energy storage (LHTES) systems used to power solar Brayton engines in microgravity environments. Specifically, a physical and numerical model of the solar heat receiver component of NASA Lewis Research Center's Ground Test Demonstration (GTD) project was developed. Multi-conjugate effects such as the convective fluid flow of a low-Prandtl-number fluid, coupled with thermal conduction in the phase change material, containment tube and working fluid conduit were accounted for in the model. A single-band thermal radiation model was also included to quantify reradiative energy exchange inside the receiver and losses through the aperture. The eutectic LiF-CaF2 was used as the phase change material (PCM) and a mixture of He/Xe was used as the working fluid coolant. A modified version of the computer code HOTTube was used to generate results in the two-phase regime. Results indicate that parametric changes in receiver gas inlet temperature and receiver heat input effects higher sensitivity to changes in receiver gas exit temperatures.

  17. Analysis of Fluid Flow and Heat Transfer in a Liquid Hydrogen Storage Vessel for Space Applications

    NASA Astrophysics Data System (ADS)

    Mukka, Santosh K.; Rahman, Muhammad M.

    2004-02-01

    This paper presents a systematic analysis of fluid flow and heat transfer in a liquid hydrogen storage vessel for both earth and space applications. The study considered a cylindrical tank with elliptical top and bottom. The tank wall is made of aluminum and a multi-layered blanket of cryogenic insulation (MLI) has been attached on the top of the aluminum. The tank is connected to a cryocooler to dissipate the heat leak through the insulation and tank wall into the fluid within the tank. The cryocooler has not been modeled; only the flow in and out of the tank to the cryocooler system has been included. The primary emphasis of this research has been the fluid circulation within the tank for different fluid distribution scenario and for different level of gravity to simulate potential earth and space based applications. The equations solved in the liquid region included the conservation of mass, conservation of energy, and conservation of momentum. For the solid region only the heat conduction equation was solved. The steady-state velocity, temperature, and pressure distributions were calculated for different inlet positions, inlet velocities, and for different gravity values. The above simulations were carried out for constant heat flux and constant wall temperature cases. It was observed that a good flow circulation could be obtained when the cold entering fluid was made to flow in radial direction and the inlet opening was placed close to the tank wall.

  18. Self-pressurization of a flightweight liquid hydrogen storage tank subjected to low heat flux

    NASA Technical Reports Server (NTRS)

    Hasan, M. M.; Lin, C. S.; Vandresar, N. T.

    1991-01-01

    Results are presented for an experimental investigation of self-pressurization and thermal stratification of a 4.89 cu m liquid hydrogen (LH2) storage tank subjected to low heat flux (0.35, 2.0, and 3.5 W/sq m) under normal gravity conditions. Tests were performed at fill levels of 83 to 84 percent (by volume). The LH2 tank was representative of future spacecraft tankage, having a low mass-to-volume ratio and high performance multilayer thermal insulation. Results show that the pressure rise rate and thermal stratification increase with increasing heat flux. At the lowest heat flux, the pressure rise rate is comparable to the homogenous rate, while at the highest heat flux, the rate is more than three times the homogeneous rate. It was found that initial conditions have a significant impact on the initial pressure rise rate. The quasi-steady pressure rise rates are nearly independent of the initial condition after an initial transient period has passed.

  19. Tree-shaped fluid flow and heat storage in a conducting solid

    NASA Astrophysics Data System (ADS)

    Combelles, L.; Lorente, S.; Anderson, R.; Bejan, A.

    2012-01-01

    This paper documents the time-dependent thermal interaction between a fluid stream configured as a plane tree of varying complexity embedded in a conducting solid with finite volume and insulated boundaries. The time scales of the convection-conduction phenomenon are identified. Two-dimensional and three-dimensional configurations are simulated numerically. The number of length scales of the tree architecture varies from one to four. The results show that the heat transfer density increases, and the time of approach to equilibrium decreases as the complexity of the tree designs increases. These results are then formulated in the classical notation of energy storage by sensible heating, which shows that the effective number of heat transfer units increases as the complexity of the tree design increases. The complexity of heat transfer designs in many applications is constrained by first cost and operating cost considerations. This work provides a fundamental basis for objective evaluation of cost and performance tradeoffs in thermal design of energy systems with complexity as an unconstrained parameter that can be actively varied over a broad range to determine the optimum system design.

  20. Tree-Shaped Fluid Flow and Heat Storage in a Conducting Solid

    SciTech Connect

    Combelles, L.; Lorente, S.; Anderson, R.; Bejan, A.

    2012-01-01

    This paper documents the time-dependent thermal interaction between a fluid stream configured as a plane tree of varying complexity embedded in a conducting solid with finite volume and insulated boundaries. The time scales of the convection-conduction phenomenon are identified. Two-dimensional and three-dimensional configurations are simulated numerically. The number of length scales of the tree architecture varies from one to four. The results show that the heat transfer density increases, and the time of approach to equilibrium decreases as the complexity of the tree designs increases. These results are then formulated in the classical notation of energy storage by sensible heating, which shows that the effective number of heat transfer units increases as the complexity of the tree design increases. The complexity of heat transfer designs in many applications is constrained by first cost and operating cost considerations. This work provides a fundamental basis for objective evaluation of cost and performance tradeoffs in thermal design of energy systems with complexity as an unconstrained parameter that can be actively varied over a broad range to determine the optimum system design.

  1. Storage Stability of Lycopene in Tomato Juice Subjected to Combined Pressure–Heat Treatments

    PubMed Central

    Gupta, Rockendra; Balasubramaniam, V. M.; Schwartz, Steven J.; Francis, David M.

    2013-01-01

    A study was conducted to characterize the storage stability of lycopene in hot-break tomato juice prepared from two different cultivars and processed by various pressure–heat combinations. Samples were subjected to pressure assisted thermal processing (PATP; 600 MPa, 100 °C, 10 min), high pressure processing (HPP; 700 MPa, 45 °C, 10 min), and thermal processing (TP; 0.1 MPa, 100 °C, 35 min). Processed samples were stored at 4, 25, and 37 °C for upto 52 weeks. HPP and PATP treatments significantly improved the extractability of lycopene over TP and control. All-trans lycopene was found to be fairly stable to isomerization during processing, and the cis isomer content of the control and processed juice did not differ significantly. During storage, lycopene degradation varied as a function of the cultivar, processing method, storage temperature, and time. This study shows that combined pressure–temperature treatments could be an attractive alternative to thermal sterilization for preserving tomato juice quality. PMID:20593824

  2. Development of approximate method to analyze the characteristics of latent heat thermal energy storage system

    SciTech Connect

    Saitoh, T.S.; Hoshi, Akira

    1999-07-01

    Third Conference of the Parties to the U.N. Framework Convention on Climate Change (COP3) held in last December in Kyoto urged the industrialized nation to reduce carbon dioxide (CO{sub 2}) emissions by 5.2 percent (on the average) below 1990 level until the period between 2008 and 2012 (Kyoto protocol). This implies that even for the most advanced countries like the US, Japan, and EU implementation of drastic policies and overcoming many barriers in market should be necessary. One idea which leads to a path of low carbon intensity is to adopt an energy storage concept. One of the reasons that the efficiency of the conventional energy systems has been relatively low is ascribed to lacking of energy storage subsystem. Most of the past energy systems, for example, air-conditioning system, do not have energy storage part and the system usually operates with low energy efficiency. Firstly, the effect of reducing CO{sub 2} emissions was also examined if the LHTES subsystems were incorporated in all the residential and building air-conditioning systems. Another field of application of the LHTES is of course transportation. Future vehicle will be electric or hybrid vehicle. However, these vehicles will need considerable energy for air-conditioning. The LHTES system will provide enough energy for this purpose by storing nighttime electricity or rejected heat from the radiator or motor. Melting and solidification of phase change material (PCM) in a capsule is of practical importance in latent heat thermal energy storage (LHTES) systems which are considered to be very promising to reduce a peak demand of electricity in the summer season and also reduce carbon dioxide (CO{sub 2}) emissions. Two melting modes are involved in melting in capsules. One is close-contact melting between the solid bulk and the capsule wall, and another is natural convection melting in the liquid (melt) region. Close-contact melting processes for a single enclosure have been solved using several numerical methods (e.g. Saitoh and Kato, 1994). In addition, close-contact melting heat transfer characteristics including melt flow in the liquid film under inner wall temperature distribution were analyzed and simple approximate equations were already presented by Saitoh and Hoshi (1997). In this paper, the authors will propose an analytical solution on combined close-contact and natural convection melting in horizontal cylindrical and spherical capsules, which is useful for the practical capsule bed LHTES system.

  3. Applications of thermal energy storage to process heat and waste heat recovery in the iron and steel industry

    NASA Technical Reports Server (NTRS)

    Katter, L. B.; Peterson, D. J.

    1978-01-01

    The system identified operates from the primary arc furnace evacuation system as a heat source. Energy from the fume stream is stored as sensible energy in a solid medium (packed bed). A steam-driven turbine is arranged to generate power for peak shaving. A parametric design approach is presented since the overall system design, at optimum payback is strongly dependent upon the nature of the electric pricing structure. The scope of the project was limited to consideration of available technology so that industry-wide application could be achieved by 1985. A search of the literature, coupled with interviews with representatives of major steel producers, served as the means whereby the techniques and technologies indicated for the specific site are extrapolated to the industry as a whole and to the 1985 time frame. The conclusion of the study is that by 1985, a national yearly savings of 1.9 million barrels of oil could be realized through recovery of waste heat from primary arc furnace fume gases on an industry-wide basis. Economic studies indicate that the proposed system has a plant payback time of approximately 5 years.

  4. Effects of the number and distribution of fins on the storage characteristics of a cylindrical latent heat energy storage system: a numerical study

    NASA Astrophysics Data System (ADS)

    Ogoh, Wilson; Groulx, Dominic

    2012-10-01

    A numerical study of the effects of the number and distribution of fins on the storage characteristics of a cylindrical latent heat energy storage system (LHESS) was conducted. Due to the low thermal conductivity of phase change materials (PCMs) used in LHESS, fins were added to the system to increase the rate of heat transfer and charging. Finite elements were used to implement the developed numerical method needed to study and solve for the phase change heat transfer (melting of PCM) encountered in a LHESS during charging. The effective heat capacity method was applied in order to account for the large amount of latent energy stored during melting of the PCM and the moving interface between the solid and liquid phases. The effects of increasing the number and distribution of fins on the melting rate of the PCM were studied for configurations having between 0 and 27 fins for heat transfer fluid (HTF) velocities of 0.05 and 0.5 m/s. Results show that the overall heat transfer rate to the PCM increases with an increase in the number of fins irrespective of the HTF velocity. It was also observed that the total amount of energy stored after 12 h increases nearly linearly with the addition of fins up to 12 fins; further addition of fins increasing the total energy stored by ever smaller amounts.

  5. Modeling Cyclic Phase Change and Energy Storage in Solar Heat Receivers

    NASA Technical Reports Server (NTRS)

    Hall, Carsie A., III; Glakpe, Emmanuel K.; Cannon, Joseph N.; Kerslake, Thomas W.

    1997-01-01

    Numerical results pertaining to cyclic melting and freezing of an encapsulated phase change material (PCM), integrated into a solar heat receiver, have been reported. The cyclic nature of the present melt/freeze problem is relevant to latent heat thermal energy storage (LHTES) systems used to power solar Brayton engines in microgravity environments. Specifically, a physical and numerical model of the solar heat receiver component of NASA Lewis Research Center's Ground Test Demonstration (GTD) project was developed and results compared with available experimental data. Multi-conjugate effects such as the convective fluid flow of a low-Prandtl-number fluid, coupled with thermal conduction in the phase change material, containment tube and working fluid conduit were accounted for in the model. A single-band thermal radiation model was also included to quantify reradiative energy exchange inside the receiver and losses through the aperture. The eutectic LiF-CaF2 was used as the phase change material (PCM) and a mixture of He/Xe was used as the working fluid coolant. A modified version of the computer code HOTTube was used to generate results for comparisons with GTD data for both the subcooled and two-phase regimes. While qualitative trends were in close agreement for the balanced orbit modes, excellent quantitative agreement was observed for steady-state modes.

  6. An investigation of the processes of heat and mass transfer in a multilayer medium under conditions of injection of a miscible agent with simultaneous electromagnetic stimulation

    Microsoft Academic Search

    A. Ya. Davletbaev; L. A. Kovaleva; N. M. Nasyrov

    2009-01-01

    A numerical investigation is performed of the impact of high-frequency (HF) electromagnetic (EM) field on the process of filtering\\u000a of miscible fluids and propagation of heat in a uniform stratum. The cross effects of heat and mass transfer, which arise\\u000a under conditions of nonisothermal motion of a multicomponent medium in porous medium, are taken into account during simulation.

  7. Central receiver solar thermal power system, Phase 1. CDRL Item 2. Pilot plant preliminary design report. Volume V. Thermal storage subsystem. [Sensible heat storage using Caloria HT43 and mixture of gravel and sand

    Microsoft Academic Search

    R. W. Jr. Hallet; R. L. Gervais

    1977-01-01

    The proposed 100-MWe Commercial Plant Thermal Storage System (TSS) employs sensible heat storage using dual liquid and solid media for the heat storage in each of four tanks, with the thermocline principle applied to provide high-temperature, extractable energy independent of the total energy stored. The 10-MW Pilot Plant employs a similar system except uses only a single tank. The high-temperature

  8. Modeling and Simulation of Solar Seasonal Underground Thermal Storage in a Solar-Ground Coupled Heat Pump System

    Microsoft Academic Search

    Wenyong Zhang; Maoyu Zheng; Xiao Wang

    2010-01-01

    This paper presents a three-dimensional unsteady state fluid-solid coupling mathematical model of multiple ground heat exchangers (GHE) used in a solar-ground coupled heat pump system (SGCHPS). The model was developed with the commercial computational fluid dynamics (CFD) software FLUENT. To simulate the long-term performance of solar seasonal underground thermal storage in SGCHPS, the mathematical models of solar collector and plate

  9. Thermal conductivity and latent heat thermal energy storage characteristics of paraffin\\/expanded graphite composite as phase change material

    Microsoft Academic Search

    Ahmet Sar?; Ali Karaipekli

    2007-01-01

    This study aimed determination of proper amount of paraffin (n-docosane) absorbed into expanded graphite (EG) to obtain form-stable composite as phase change material (PCM), examination of the influence of EG addition on the thermal conductivity using transient hot-wire method and investigation of latent heat thermal energy storage (LHTES) characteristics of paraffin such as melting time, melting temperature and latent heat

  10. Heating and cooling system

    Microsoft Academic Search

    1976-01-01

    An environment heating and cooling system is described which consists of a solar collector, heat storage ground well, cold storage ground well, and a heat exchange apparatus. Water from a cold storage ground well is heated in the heat exchange apparatus by solar heating fluid heated in a solar collector. The heated water is stored in a heat storage ground

  11. Examinations on the Meteorologic Factors of Urban Heat Island Development in Small and Medium-sized Towns of Hungary

    NASA Astrophysics Data System (ADS)

    Szegedi, S.; Gyarmati, R.; Kapocska, L.; Toth, T.

    2010-09-01

    EXAMINATIONS ON THE METEOROLOGICAL FACTORS OF URBAN HEAT ISLAND DEVELOPMENT IN SMALL AND MEDIUM-SIZED TOWNS OF HUNGARY Sandor Szegedi, Renata Gyarmati, Laszlo Kapocska and Tamas Toth University of Debrecen Department of Meteorology, 4032 Debrecen Egyetem tér 1. The thermal difference between the settlements and their environment is called urban heat island (UHI). Potential UHI intensities are mainly determined by the size, population and built-up structure of settlements. Meteorological conditions have a determinant impact on the development of the heat island at a certain moment. International and Hungarian studies usually deal with metropolises and big cities; much less attention is paid to medium-sized and small towns. Consequently this study has been focused on the development of UHI in such Hungarian urbanized areas as mentioned above. Settlements, located near the city of Debrecen (ca. 220,000 inhabitants) in East Hungary, with population of about 30000, 20000 10000 and 1000 were chosen for the research. Car-mounted digital thermometers with data loggers were used. Twenty four measurements were carried out during a one-year-long campaign in 2003-2004. Synoptic conditions, especially cloudiness, wind direction and wind speed were taken to consideration as determinant factors. Spatial characteristics of UHI have been described. Results have proved the existence of UHI even in the smallest settlement under suitable weather conditions. The non-heating season proved to be more advantageous for the development of UHI due to stronger irradiance and frequent anticyclonic synoptic conditions. Effects of cloudiness and wind speed have been revealed as well. St type clouds have proved to be most effective in preventing the formation of UHI. A 90-100% St cover could completely eliminate the thermal differences between natural and artificial surfaces. Ci type clouds had the weakest impact, they could prevent the formation of the heat island only in the smallest settlement involved in the study. In that cases when favorable synoptic conditions prevailed within 48-72 hours before the measurements, but during the measuring cloudiness reached 50%, strong UHI could not develop in any settlement, while over 75% only weak UHI could form in the big city. Over 90% there were no heat island found in any settlements involved here. Wind speed had a strong impact on the strength of the heat island, while wind directions affected its shape merely. It was found that winds of 1-1.5 m/s (measured at a height of 2 metres) could prevent the formation of an UHI in settlements with 10000 inhabitants and below. In such cases in settlements with 20000-300000 inhabitants, only medium intensity heat islands could develop, and the intensity curve became asymmetric as the heat island was pushed towards the lee side. In case of stronger 2.5-3 m/s winds, UHI could develop only in Debrecen. The intensity in such cases (2-3 °C) reached only about half of the characteristic intensity of ideal circumstances. The shape was usually drifted strongly lee wards. Over a wind speed 3 m/s, at a height of 2 m heat island could not develop in any settlements involved in the study.

  12. Applications of thermal energy storage to process heat storage and recovery in the paper and pulp industry

    NASA Technical Reports Server (NTRS)

    Carr, J. H.; Hurley, P. J.; Martin, P. J.

    1978-01-01

    Applications of Thermal Energy Storage (TES) in a paper and pulp mill power house were studied as one approach to the transfer of steam production from fossil fuel boilers to waste fuel of (hog fuel) boilers. Data from specific mills were analyzed, and various TES concepts evaluated for application in the process steam supply system. Constant pressure and variable pressure steam accumulators were found to be the most attractive storage concepts for this application.

  13. Thermal reliability test of some fatty acids as PCMs used for solar thermal latent heat storage applications

    Microsoft Academic Search

    Ahmet Sar?

    2003-01-01

    The purpose of this study is to determine the thermal reliability of stearic acid, palmitic acid, myristic acid and lauric acid as latent heat energy storage materials with respect to various numbers of thermal cycles. The fatty acids, as phase change materials (PCMs), of industrial grade (purity between 90% and 97%) were subjected to accelerated thermal cycle tests. The differential

  14. Modeling the effect of antecedent soil water storage on water and heat status in seasonally freezing and thawing agricultural soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Taking Hetao Irrigation District of Inner Mongolia's agricultural production as a background and based on field observation data and field measured meteorological data, the influence of antecedent soil water storage (ASWS) on water and heat conditions was simulated and analyzed using the SHAW model ...

  15. Heat Production and Storage Are Positively Correlated with Measures of Body Size/Composition and Heart Rate Drift during Vigorous Running

    ERIC Educational Resources Information Center

    Buresh, Robert; Berg, Kris; Noble, John

    2005-01-01

    The purposes of this study were to determine the relationships between: (a) measures of body size/composition and heat production/storage, and (b) heat production/storage and heart rate (HR) drift during running at 95 % of the velocity that elicited lactate threshold, which was determined for 20 healthy recreational male runners. Subsequently,…

  16. Numerical prediction of heat transfer by natural convection and radiation in an enclosure filled with an isotropic scattering medium

    NASA Astrophysics Data System (ADS)

    Moufekkir, F.; Moussaoui, M. A.; Mezrhab, A.; Naji, H.; Lemonnier, D.

    2012-09-01

    This paper deals with the numerical solution for natural convection and volumetric radiation in an isotropic scattering medium within a heated square cavity using a hybrid thermal lattice Boltzmann method (HTLBM). The multiple relaxation time lattice Boltzmann method (MRT-LBM) has been coupled to the finite difference method (FDM) to solve momentum and energy equations, while the discrete ordinates method (DOM) has been adopted to solve the radiative transfer equation (RTE) using the S8 quadrature. Based on these approaches, the effects of various influencing parameters such as the Rayleigh number (Ra), the wall emissivity (??), the Planck number (Pl), and the scattering albedo (?), have been considered. The results presented in terms of isotherms, streamlines and averaged Nusselt number, show that in absence of radiation, the temperature and the flow fields are centro-symmetrics and the cavity core is thermally stratified. However, radiation causes an overall increase in the temperature and velocity gradients along both thermally active walls. The maximum heat transfer rate is obtained when the surfaces of the enclosure walls are regarded as blackbodies. It is also seen that the scattering medium can generate a multicellular flow.

  17. Dynamic characteristics of heat transfer coefficient in pressurized bubble columns with viscous liquid medium

    Microsoft Academic Search

    Yong Jun Cho; Kwang Jae Woo; Yong Kang; Sang Done Kim

    2002-01-01

    Dynamic characteristics of heat transfer coefficient have been investigated in a pressurized bubble column (0.152 m, i.d. and 2.0 m in height) by adopting the chaos theory. Effects of gas velocity (0–0.12 m\\/s), pressure (0.1–0.6 MPa) and liquid viscosity (1.0–38.0 mPa s) on the immersed heater-to-column heat transfer characteristics have been examined. The temperature difference fluctuations between the immersed heater

  18. Eigenvalue approach to fractional order generalized magneto-thermoelastic medium subjected to moving heat source

    NASA Astrophysics Data System (ADS)

    Abbas, Ibrahim A.

    2015-03-01

    In the present work, we consider the problem of fractional order thermoelastic interaction in a material placed in a magnetic field and subjected to a moving plane of heat source. The basic equations have been written in the form of a vector-matrix differential equation in the Laplace transform domain, which is then solved by an eigenvalue approach. The inverse Laplace transforms are computed numerically and some comparisons have been shown in figures to estimate the effect of each of the fractional order, heat source velocity, time and the magnetic field and parameters.

  19. Solar energy storage - Digital simulation of energy transfer by conduction and radiation in a two-phase medium

    Microsoft Academic Search

    D. Gobin; D. Levesque; C. Benard

    1979-01-01

    The paper studies the time evolution of temperature distribution and the melting level velocity in a solar energy thermal storage system. The storage material used is a paraffin wax that melts at 52 C. The solar radiation comes in through a greenhouse effect. This simulation can be used to describe the behavior of roofs or walls that store solar energy

  20. Development of media for dynamic latent heat storage for the low-temperature range. Part 1: Thermal analyses of selected salt hydrate systems

    NASA Technical Reports Server (NTRS)

    Kanwischer, H.; Tamme, R.

    1985-01-01

    Phase change temperatures and phase change enthalpies of seventeen salt hydrates, three double salts, and four eutectics were measured thermodynamically and the results reported herein. Good results were obtained, especially for congruently melting salt hydrates. Incongruently melting salt hydrates appear less suitable for heat storage applications. The influence of the second phase - water, acid and hydroxide - to the latent heat is described. From these results, basic values of the working temperatures and storage capabilities of various storage media compositions may be derived.

  1. Programming MOFs for water sorption: amino-functionalized MIL-125 and UiO-66 for heat transformation and heat storage applications.

    PubMed

    Jeremias, Felix; Lozan, Vasile; Henninger, Stefan K; Janiak, Christoph

    2013-12-01

    Sorption-based heat transformation and storage appliances are very promising for utilizing solar heat and waste heat in cooling or heating applications. The economic and ecological efficiency of sorption-based heat transformation depends on the availability of suitable hydrophilic and hydrothermally stable sorption materials. We investigated the feasibility of using the metal-organic frameworks UiO-66(Zr), UiO-67(Zr), H2N-UiO-66(Zr) and H2N-MIL-125(Ti) as sorption materials in heat transformations by means of volumetric water adsorption measurements, determination of the heat of adsorption and a 40-cycle ad/desorption stress test. The amino-modified compounds H2N-UiO-66 and H2N-MIL-125 feature high heat of adsorption (89.5 and 56.0 kJ mol(-1), respectively) and a very promising H2O adsorption isotherm due to their enhanced hydrophilicity. For H2N-MIL-125 the very steep rise of the H2O adsorption isotherm in the 0.1 < p/p0 < 0.2 region is especially beneficial for the intended heat pump application. PMID:23864023

  2. 28 To Order, Call or Shop Online at omega.comSM MEDIUM TEMPERATURE HEATING TAPES

    E-print Network

    Washington at Seattle, University of - Department of Physics, Electroweak Interaction Research Group

    of integrally molded separable plug OMEGALUX® silicone rubber extruded heating tapes are low- watt density and chemical resistance. Silicone rubber tapes are constructed of finely stranded resistance wires fully are encapsulated in a void- free silicone rubber sheath. Maximum Exposure Temperature up to 230°C (450°F) Uniform

  3. Laboratory Evaluation of Gas-Fired Tankless and Storage Water Heater Approaches to Combination Water and Space Heating

    SciTech Connect

    Kingston, T.; Scott, S.

    2013-03-01

    Homebuilders are exploring more cost effective combined space and water heating systems (combo systems) with major water heater manufacturers that are offering pre-engineered forced air space heating combo systems. In this project, unlike standardized tests, laboratory tests were conducted that subjected condensing tankless and storage water heater based combo systems to realistic, coincidental space and domestic hot water loads with the following key findings: 1) The tankless combo system maintained more stable DHW and space heating temperatures than the storage combo system. 2) The tankless combo system consistently achieved better daily efficiencies (i.e. 84%-93%) than the storage combo system (i.e. 81%- 91%) when the air handler was sized adequately and adjusted properly to achieve significant condensing operation. When condensing operation was not achieved, both systems performed with lower (i.e. 75%-88%), but similar efficiencies. 3) Air handlers currently packaged with combo systems are not designed to optimize condensing operation. More research is needed to develop air handlers specifically designed for condensing water heaters. 4) System efficiencies greater than 90% were achieved only on days where continual and steady space heating loads were required with significant condensing operation. For days where heating was more intermittent, the system efficiencies fell below 90%.

  4. Energy Balance Comparison and Closure at a Moist Desert Playa: The Importance of Ground Heat Storage and Flux Estimation

    NASA Astrophysics Data System (ADS)

    Huntington, J. L.; Rajagopal, S.; Allen, R. G.; Mihevc, T. M.; Schumer, R.; Caldwell, T.; deBruin, H.

    2012-12-01

    Given increasing demands on finite water supplies in arid environments, the need for accurate estimates of sustainable groundwater resources is greater than ever. Many drainages in desert environments are considered hydrologically closed, where the entire groundwater recharge volume is consumed by evaporation and evapotranspiration along mountain front and valley floor areas. The amount of groundwater recharge that occurs in a given hydrographic basin is difficult to accurately estimate and is therefore commonly quantified by estimating the groundwater discharge using micrometeorological, and remote and in situ energy balance methods. Large playas are common features in desert environments, and the phreatic surface is often less than a few meters below land surface, creating nearly saturated conditions at the land surface through capillary rise. At first glance one might conclude that evaporation is high due to the nearly saturated surface, however, playa surfaces are commonly sealed by thin salt crusts, inhibiting evaporation. In this work we use eddy covariance, scintillometer, and four component radiometer measurements, and present a novel ground heat flux analysis using multiple ground heat flux plates and heat-pulse sensors to assess energy balance closure and uncertainties on estimated evaporation in Dixie Valley, Nevada. Results indicate that greater than 50 percent of daytime net radiation is partitioned into ground heat flux, and almost all of the available energy is portioned into sensible heat as determined from eddy covariance, and confirmed with scintillometer estimates. Utilizing heat pulse derived soil thermal properties and high density discrete soil temperature measurements allowed for estimation of soil heat storage and flux using a finite difference solution to the transient heat flow equation. This approach improved energy balance closure by 20 percent (achieving 90 percent closure) when compared to traditional calorimetric soil heat storage and flux estimates. We found that underestimation of energy balance closure occurs due to phase lags between 30 minute average available energy and turbulent fluxes, and is primarily due to inaccurate accounting of soil heat storage. Our work highlights the importance of accurate ground heat storage and flux estimation and provides insight into solving the surface energy imbalance problem in complex desert environments.

  5. Thermal radiation and chemical reaction effects on MHD mixed convective boundary layer slip flow in a porous medium with heat source and Ohmic heating

    NASA Astrophysics Data System (ADS)

    Gnaneswara Reddy, Machireddy

    2014-03-01

    An analytical study for the problem of mixed convection with thermal radiation and first-order chemical reaction on magnetohydrodynamics boundary layer flow of viscous, electrically conducting fluid past a vertical permeable surface embedded in a porous medium has been presented. Slip boundary condition is applied at the porous interface. The heat equation includes the terms involving the viscous dissipation, radiative heat flux, Ohmic dissipation, the internal absorption and absorption of radiation, whereas the mass transfer equation includes the effects of chemically reactive species of first order. The dimensionless governing equations for this investigation are formulated and the non-linear coupled differential equations are solved analytically using the perturbation technique. Comparisons with previously published work on special cases of the problem are performed and results are found to be in excellent agreement. The results obtained show that the velocity, temperature and concentration fields are appreciably influenced by the presence of magnetic field, thermal radiation, chemical reaction and Ohmic dissipation. It is observed that the effect of magnetic field, heat source and thermal radiation is to decrease the velocity, temperature profiles in the boundary layer. The effect of increasing the values of rarefaction parameter is to increase the velocity in the momentum boundary layer. Further, it is found that increasing the value of the chemical reaction decreases the concentration of species in the boundary layer. Also, the effects of the various parameters on the skin-friction coefficient, local Nusselt number and local Sherwood number at the surface are discussed.

  6. Storage of H2 by absorption and/or mixture within a fluid medium

    DOEpatents

    Berry, Gene David; Aceves, Salvador Martin

    2007-03-20

    For the first time, a hydrogen storage method, apparatus and system having a fluid mixture is provided. At predetermined pressures and/or temperatures within a contained substantially fixed volume, the fluid mixture can store a high density of hydrogen molecules, wherein a predetermined phase of the fluid mixture is capable of being withdrawn from the substantially fixed volume for use as a vehicle fuel or energy storage having reduced and/or eliminated evaporative losses, especially where storage weight, vessel cost, vessel shape, safety, and energy efficiency are beneficial.

  7. Applications of thermal energy storage to process heat storage and recovery in the paper and pulp industry

    Microsoft Academic Search

    W. D. Beverly; M. Rubeck; G. L. Vieth; P. J. Hurley

    1978-01-01

    Applications of Thermal Energy Storage (TES) in a paper and pulp mill powerhouse were studied as one approach to the transfer of steam production from fossil fuel boilers to waste fuel (''hog fuel'') boilers. Data from specific mills were analyzed, and various TES concepts evaluated for application in the process steam supply system. Constant pressure and variable pressure steam accumulators

  8. Integrated space heating, air conditioning and potable water heating appliance

    SciTech Connect

    Gerstmann, J.; Celorier, G.M. Jr.; Hill, W.S.

    1989-01-17

    An integrated water heating and space heating and cooling appliance is described comprising: a housing having a lower water storage section, a middle burner section, and an upper internal air handling section in an internal portion, and having a side external air handling section extending from the internal portion to pass through a building wall; an insulated hot water storage tank in the lower section of the housing; a burner and burner heat exchanger in the middle section for heating a liquid heating medium; a liquid to air heat exchanger in the upper section; a heat transfer fluid circuit means for selectively directing heating medium from the burner heat exchanger in the middle section into heat exchange relationship with hot water in the hot water storage tank; an air conditioner evaporator in the upper section adjacent to and in face to face relationship with the liquid to air heat exchanger; a blower in the upper section for blowing space conditioning air past the liquid to air heat exchanger and the evaporator for heating the air by the heat exchanger or cooling the air by the evaporator; an air conditioner condenser in the side section; a compressor operatively connected by conduit means to the compressor and evaporator to form a refrigeration system; and a blower in the side section for blowing external air past the condenser.

  9. Improvement of a thermal energy storage using plates with paraffin–graphite composite

    Microsoft Academic Search

    José M. Marín; Belén Zalba; Luisa F. Cabeza; Harald Mehling

    2005-01-01

    This work aims at designing a thermal energy storage (TES) using air as heat transfer medium, efficient mainly for free-cooling but also for other applications, improving the low heat transfer rates dues to the thermal conductivity of the materials usually employed in these systems, phase change materials (PCM). In this paper, free-cooling means the storage of cold from the night

  10. Experimental study of a solar-assisted ground-coupled heat pump system with solar seasonal thermal storage in severe cold areas

    Microsoft Academic Search

    Xiao Wang; Maoyu Zheng; Wenyong Zhang; Shu Zhang; Tao Yang

    2010-01-01

    This paper presents the experimental study of a solar-assisted ground-coupled heat pump system (SAGCHPS) with solar seasonal thermal storage installed in a detached house in Harbin. The solar seasonal thermal storage was conducted throughout the non-heating seasons. In summer, the soil was used as the heat sink to cool the building directly. In winter, the solar energy was used as

  11. The behavior of a long term heat storage system in connection with a wind energy converter (phase 1)

    NASA Astrophysics Data System (ADS)

    Auer, F.; Bley, H.; Mueller, M.

    1982-04-01

    The technical and economical feasibility of heating a museum on the Wasserkuppe mountain (950 m) in the Rhoen hills by wind energy is affirmed. It is possible to recover the capital cost within a period of 15 to 19 years if the service life of the wind energy converter (WEC) and of the heat storage system is between 20 and 30 years. At a maximum thermal load of 120 kW, the minimum cost will be achieved with a WEC power output of 120 kW and a two day storage system. This combination permits 60% of the heat demand to be covered by wind energy. The balance has to be supplied by conventional energy sources. The wind energy fraction of the total energy demand thus is about twice as high as the solar fraction in the case of solar heating systems and about 15% higher than the fraction of ambient heating energy in the case of electric heat pumps used in bivalent operation. The wind price per kWh is already comparable to that expected for the future large wind energy converters (GROWIAN) to be produced in series.

  12. Heat transfer in a medium in which many small particles are embedded

    E-print Network

    A. G. Ramm

    2012-07-03

    The heat equation is considered in the complex system consisting of many small bodies (particles) embedded in a given material. On the surfaces of the small bodies a Newton-type boundary condition is imposed. An equation for the limiting field is derived when the characteristic size $a$ of the small bodies tends to zero, their total number $\\mathcal{N}(a)$ tends to infinity at a suitable rate, and the distance $d = d(a)$ between neighboring small bodies tends to zero $a << d$. No periodicity is assumed about the distribution of the small bodies.

  13. Keeping the Universe ionised: Photo-heating and the clumping factor of the high-redshift intergalactic medium

    E-print Network

    Andreas H. Pawlik; Joop Schaye; Eveline van Scherpenzeel

    2009-01-10

    The critical star formation rate density required to keep the intergalactic hydrogen ionised depends crucially on the average rate of recombinations in the intergalactic medium (IGM). This rate is proportional to the clumping factor C = / avg(rho_b)^2, where rho_b and avg(rho_b) are the local and cosmic mean baryon density, respectively, and the brackets indicate spatial averaging over the recombining gas in the IGM. We perform a suite of cosmological smoothed particle hydrodynamics simulations that include radiative cooling to calculate the volume-weighted clumping factor of the IGM at redshifts z >= 6. We focus on the effect of photo-ionisation heating by a uniform ultra-violet background and find that photo-heating strongly reduces the clumping factor because the increased pressure support smoothes out small-scale density fluctuations. Photo-ionisation heating is often said to provide a negative feedback on the reionisation of the IGM because it suppresses the cosmic star formation rate by boiling the gas out of low-mass halos. However, because of the reduction of the clumping factor it also makes it easier to keep the IGM ionised. Photo-heating therefore also provides a positive feedback which, while known to exist, has received much less attention. We demonstrate that this positive feedback is in fact very strong. Using conservative assumptions, we find that if the IGM was reheated at z >~ 9, the observed population of star-forming galaxies at z = 6 may be sufficient to keep the IGM ionised, provided that the fraction of ionising photons that escape the star-forming regions to ionise the IGM is larger than 0.2.

  14. Time resolved spectra in the infrared absorption and emission from shock heated hydrocarbons. [in interstellar medium

    NASA Technical Reports Server (NTRS)

    Bauer, S. H.; Borchardt, D. B.

    1990-01-01

    The wavelength range of a previously constructed multichannel fast recording spectrometer was extended to the mid-infrared. With the initial configuration, light intensities were recorded simultaneously with a silicon-diode array simultaneously at 20 adjacent wavelengths, each with a 20-micron time resolution. For studies in the infrared, the silicon diodes were replaced by a 20-element PbSe array of similar dimensions, cooled by a three-stage thermoelectric device. It is proposed that infrared emissions could be due to shock-heated low molecular-weight hydrocarbons. The full Swan band system appeared in time-integrated emission spectra from shock-heated C2H2; no soot was generated. At low resolution, the profiles on the high-frequency side of the black body maximum show no distinctive features. These could be fitted to Planck curves, with temperatures that declined with time from an initial high that was intermediate between T5 (no conversion) and T5(eq).

  15. Enrichment and heating of the intracluster medium by ejection from galaxies

    NASA Technical Reports Server (NTRS)

    Metzler, Chris; Evrard, August

    1993-01-01

    Results of N-body + hydrodynamic simulations designed to model the formation and evolution of clusters of galaxies and intracluster gas are presented. Clusters of galaxies are the largest bound, relaxed objects in the universe. They are strong x-ray emitters; this radiation originates through thermal bremsstrahlung from a diffuse plasma filling the space between cluster galaxies, the intracluster medium or ICM. From observations, one can infer that the mass of the ICM is comparable to or greater than the mass of all the galaxies in the cluster, and that the ratio of mass in hot gas to mass in galaxies, M(sub ICM)/M(sub STARS), increases with the richness of the cluster. Spectroscopic studies of cluster x-ray emission show heavy element emission lines. While M(sub ICM)/M(sub STARS) is greater than or equal to 1 implies that most of the ICM is primordial in nature, the discovery of heavy elements indicates that some of the gas must have been processed through galaxies. Galaxy evolution thus directly impacts cluster evolution.

  16. Effect of processing by hydrostatic high pressure of two ready to heat vegetable meals and stability after refrigerated storage.

    PubMed

    Masegosa, Rosa; Delgado-Adámez, Jonathan; Contador, Rebeca; Sánchez-Íñiguez, Francisco; Ramírez, Rosario

    2014-12-01

    The effect of high pressure processing (HPP) (400 and 600?MPa for 1 and 5?min) and the stability during storage were studied in two ready to heat vegetable meals: meal A, mainly composed by pumpkin and broccoli, and meal B, mainly composed by eggplant, zucchini, chard and spinach. The treatment at 600?MPa/5?min was the most effective to reduce the initial microbial loads of the meals and maintained better the microbial safety during storage. HPP had no effect on the physico-chemical and sensory properties. HPP at 600?MPa increased the antioxidant activity of the meal A. In contrast HPP reduced the antioxidant activity of the meal B, although in general high levels of antioxidants were maintained after processing and during storage. In conclusion, treatments at 600?MPa for 5?min were the most suitable to increase the shelf-life of the meals without affecting their physico-chemical, antioxidant and sensory properties. PMID:23908392

  17. The Extended Fe distribution in the intracluster medium and the implications regarding AGN Heating

    E-print Network

    Laurence P. David; Paul E. J. Nulsen

    2008-09-17

    We present a systematic analysis of XMM-Newton observations of 8 cool-core clusters of galaxies and determine the Fe distribution in the intracluster medium relative to the stellar distribution in the central dominant galaxy (CDG). Our analysis shows that the Fe is significantly more extended than the stellar mass in the CDG in all of the clusters in our sample, with a slight trend of increasing extent with increasing central cooling time. The excess Fe within the central 100 kpc in these clusters can be produced by Type Ia supernovae from the CDG over the past 3-7 Gyr. Since the excess Fe primarily originates from the CDG, it is a useful probe for determining the motion of the gas and the mechanical energy deposited by AGN outbursts over the past $\\sim$ 5 Gyr in the centers of clusters. We explore two possible mechanisms for producing the greater extent of the Fe relative to the stars in the CDG, including: bulk expansion of the gas and turbulent diffusion of Fe. Assuming the gas and Fe expand together, we find that a total energy of $10^{60} - 10^{61}$~erg~s$^{-1}$ must have been deposited into the central 100 kpc of these clusters to produce the presently observed Fe distributions. Since the required enrichment time for the excess Fe is approximately 5 Gyr in these clusters, this gives an average AGN mechanical power over this time of $10^{43} - 10^{44}$~erg~s$^{-1}$. The extended Fe distribution in cluster cores can also arise from turbulent diffusion. Assuming steady-state (i.e., the outward mass flux of Fe across a given surface is equal to the mass injection rate of Fe within that surface) we find that diffusion coefficients of $10^{29} - 10^{30}$ cm$^2$~s$^{-1}$ are required to maintain the presently observed Fe profiles (abridged).

  18. Some fatty acids used for latent heat storage: thermal stability and corrosion of metals with respect to thermal cycling

    Microsoft Academic Search

    A Sar?; K Kaygusuz

    2003-01-01

    The present study includes thermal stability of some fatty acids as phase change materials (PCMs). The selected fatty acids were stearic, palmitic, myristic and lauric acid with melting temperatures between 40–63°C and industrial-grade with 90–95 % purity. Latent heat storage capacity and phase transition temperature of the PCMs were determined by Differential Scanning Calorimetry (DSC) technique as a function of

  19. Compositional, functional and storage properties of flours from raw and heat processed African breadfruit ( Treculia africana Decne) seeds

    Microsoft Academic Search

    Sunday Y. Giami; Matthew N. Adindu; Monday O. Akusu; Juliet N. T. Emelike

    2000-01-01

    African breadfruit (Treculia africana Decne) seeds were either boiled or roasted and then milled into flour. Chemical composition, functional properties and storage characteristics of raw and treated flours and the effect of partial proteolysis on selected functional properties of the raw flour were determined. Raw flour contained 20.1% crude protein, 2.5% total ash and 13.7% fat. Heat processing significantly (pp<0.05)

  20. Research on solar energy storage subsystems utilizing the latent heat of phase change of paraffin hydrocarbons for the heating and cooling of buildings. Semi-annual report, September 1, 1974March 31, 1975

    Microsoft Academic Search

    J. A. Bailey; J. C. Mulligan; C. K. Liao; S. I. Guceri

    1975-01-01

    An analytical and experimental research program designed to assess the potential of a solar energy storage subsystem (thermal capacitor) utilizing the latent heat of fusion of paraffin hydrocarbons for the heating and cooling of buildings, and supported with grant funds from the National Science Foundation, is described. An idealized model of a flat plate thermal capacitor based on uniaxial heat

  1. Efficient Phase-Change Materials: Development of a Low-Cost Thermal Energy Storage System Using Phase-Change Materials with Enhanced Radiation Heat Transfer

    SciTech Connect

    None

    2011-12-05

    HEATS Project: USF is developing low-cost, high-temperature phase-change materials (PCMs) for use in thermal energy storage systems. Heat storage materials are critical to the energy storage process. In solar thermal storage systems, heat can be stored in these materials during the day and released at night—when the sun is not out—to drive a turbine and produce electricity. In nuclear storage systems, heat can be stored in these materials at night and released to produce electricity during daytime peak-demand hours. Most PCMs do not conduct heat very well. Using an innovative, electroless encapsulation technique, USF is enhancing the heat transfer capability of its PCMs. The inner walls of the capsules will be lined with a corrosion-resistant, high-infrared emissivity coating, and the absorptivity of the PCM will be controlled with the addition of nano-sized particles. USF’s PCMs remain stable at temperatures from 600 to 1,000°C and can be used for solar thermal power storage, nuclear thermal power storage, and other applications.

  2. Measurement of the heat transfer rate for thermal energy storage masses in direct gain passive solar heating systems

    NASA Astrophysics Data System (ADS)

    Faunce, S. F.; Rickert, R. K.

    The measurement of heat transfer and the amount of thermal energy stored in thermal mass used in a passive solar heating system is described. A thermal flux meter measured the rate of heat transfer. A time relationship for the solar energy absorbed and discharged by the mass was obtained. Different orientations of the irradiated surface which consisted of different materials such as brick, concrete and phase change materials were measured. Measurements for various mass composites give values of heat transfer for absorptive of the solar irradiated surface for horizontally oriented masses and for the same masses in a vertical position.

  3. BWR spent fuel storage cask performance test. Volume 2. Pre- and post-test decay heat, heat transfer, and shielding analyses

    SciTech Connect

    Wiles, L.E.; Lombardo, N.J.; Heeb, C.M.; Jenquin, U.P.; Michener, T.E.; Wheeler, C.L.; Creer, J.M.; McCann, R.A.

    1986-06-01

    This report describes the decay heat, heat transfer, and shielding analyses conducted in support of performance testing of a Ridhihalgh, Eggers and Associates REA 2033 boiling water reactor (BWR) spent fuel storage cask. The cask testing program was conducted for the US Department of Energy (DOE) Commercial Spent Fuel Management Program by the Pacific Northwest Laboratory (PNL) and by General Electric at the latters' Morris Operation (GE-MO) as reported in Volume I. The analyses effort consisted of performing pretest calculations to (1) select spent fuel for the test; (2) symmetrically load the spent fuel assemblies in the cask to ensure lateral symmetry of decay heat generation rates; (3) optimally locate temperature and dose rate instrumentation in the cask and spent fuel assemblies; and (4) evaluate the ORIGEN2 (decay heat), HYDRA and COBRA-SFS (heat transfer), and QAD and DOT (shielding) computer codes. The emphasis of this second volume is on the comparison of code predictions to experimental test data in support of the code evaluation process. Code evaluations were accomplished by comparing pretest (actually pre-look, since some predictions were not completed until testing was in progress) predictions with experimental cask testing data reported in Volume I. No attempt was made in this study to compare the two heat transfer codes because results of other evaluations have not been completed, and a comparison based on one data set may lead to erroneous conclusions.

  4. New Carbon-Based Porous Materials with Increased Heats of Adsorption for Hydrogen Storage

    SciTech Connect

    Snurr, Randall Q.; Hupp, Joseph T.; Kanatzidis, Mercouri G.; Nguyen, SonBinh T.

    2014-11-03

    Hydrogen fuel cell vehicles are a promising alternative to internal combustion engines that burn gasoline. A significant challenge in developing fuel cell vehicles is to store enough hydrogen on-board to allow the same driving range as current vehicles. One option for storing hydrogen on vehicles is to use tanks filled with porous materials that act as “sponges” to take up large quantities of hydrogen without the need for extremely high pressures. The materials must meet many requirements to make this possible. This project aimed to develop two related classes of porous materials to meet these requirements. All materials were synthesized from molecular constituents in a building-block approach, which allows for the creation of an incredibly wide variety of materials in a tailorable fashion. The materials have extremely high surface areas, to provide many locations for hydrogen to adsorb. In addition, they were designed to contain cations that create large electric fields to bind hydrogen strongly but not too strongly. Molecular modeling played a key role as a guide to experiment throughout the project. A major accomplishment of the project was the development of a material with record hydrogen uptake at cryogenic temperatures. Although the ultimate goal was materials that adsorb large quantities of hydrogen at room temperature, this achievement at cryogenic temperatures is an important step in the right direction. In addition, there is significant interest in applications at these temperatures. The hydrogen uptake, measured independently at NREL was 8.0 wt %. This is, to the best of our knowledge, the highest validated excess hydrogen uptake reported to date at 77 K. This material was originally sketched on paper based on a hypothesis that extended framework struts would yield materials with excellent hydrogen storage properties. However, before starting the synthesis, we used molecular modeling to assess the performance of the material for hydrogen uptake. Only after modeling suggested record-breaking hydrogen uptake at 77 K did we proceed to synthesize, characterize, and test the material, ultimately yielding experimental results that agreed closely with predictions that were made before the material was synthesized. We also synthesized, characterized, and computationally simulated the behavior of two new materials displaying the highest experimental Brunauer?Emmett?Teller (BET) surface areas of any porous materials reported to date (?7000 m2/g). Key to evacuating the initially solvent-filled materials without pore collapse, and thereby accessing the ultrahigh areas, was the use of a supercritical CO2 activation technique developed by our team. In our efforts to increase the hydrogen binding energy, we developed the first examples of “zwitterionic” metal-organic frameworks (MOFs). The two structures feature zwitterionic characteristics arising from N-heterocyclic azolium groups in the linkers and negatively charged Zn2(CO2)5 nodes. These groups interact strongly with the H2 quadrupole. High initial isosteric heats of adsorption for hydrogen were measured at low H2 loading. Simulations were used to determine the H2 binding sites, and results were compared with inelastic neutron scattering. In addition to MOFs, the project produced a variety of related materials known as porous organic frameworks (POFs), including robust catechol-functionalized POFs with tunable porosities and degrees of functionalization. Post-synthesis metalation was readily carried out with a wide range of metal precursors (CuII, MgII, and MnII salts and complexes), resulting in metalated POFs with enhanced heats of hydrogen adsorption compared to the starting nonmetalated materials. Isosteric heats of adsorption as high as 9.6 kJ/mol were observed, compared to typical values around 5 kJ/mol in unfunctionalized MOFs and POFs. Modeling played an important role throughout the project. For example, we used molecular simulations to determine that the optimal isosteric heat of adsorption (Qst) for maximum hydrogen delivery using MOFs is appro

  5. Evaluation of a simple and cost effective filter paper-based shipping and storage medium for environmental sampling of F-RNA coliphages.

    PubMed

    Pérez-Méndez, A; Chandler, J C; Bisha, B; Coleman, S M; Zhanqiang, S; Gang, Y; Goodridge, L D

    2013-12-01

    Male specific RNA (F-RNA) coliphages are used as indicators of fecal contamination and for source tracking. However, collecting fecal samples for analysis from remote sites is problematic due to the need for an uninterrupted cold chain to guarantee sample suitability for downstream molecular detection of these coliphages. Here, we investigated the feasibility of using filter paper as a collection and storage vehicle for F-RNA coliphages. Various concentrations (10(1) to 10(4)pfu) of two F-RNA coliphages, MS2 and Q?, were prepared in lambda buffer or a 10% bovine manure slurry, spotted onto filter paper disks, dried, and maintained at 37 °C for up to 37 days. Nucleic acids were extracted from the spotted filter paper disks at 0, 6, 13, and 37 days post inoculation and analyzed by real time RT-PCR. F-RNA coliphages at concentrations of 10(2)pfu/filter paper unit were readily detected, and only a slight decrease in nucleic acid detection was observed over time. Furthermore, the sensitivity of real time RT-PCR detection of the F-RNA coliphage RNA was similar between the developed filter paper sampling methodology and traditional cold storage. These results indicate that filter paper is a suitable storage and transport medium for F-RNA coliphages when refrigeration is not possible. PMID:23954843

  6. Annual Collection and Storage of Solar Energy for the Heating of Buildings, Report No. 3. Semi-Annual Progress Report, August 1977 - January 1978.

    ERIC Educational Resources Information Center

    Beard, J. Taylor; And Others

    This report is part of a series from the Department of Energy on the use of solar energy in heating buildings. Described here is a new system for year around collection and storage of solar energy. This system has been operated at the University of Virginia for over a year. Composed of an underground hot water storage system and solar collection,…

  7. Modeling Heat Transfer Prediction For Icy-ball Thermal Energy Storage System

    Microsoft Academic Search

    Taveewat Suparos; Jirawan Tiansuwan; Tanongkiat Kiatsiriroat

    This paper presents a numerical model to simulate a storage system composed of spherical capsules( balls ) filled with phase change material (water ) placed inside a horizontal cylindrical tank and fitted with a working fluid circulation system to charge and discharge the storage tank. The simplified one-dimensional model is based on pure conduction in the phase charge material subject

  8. Review of Solar Thermal Storage Techniques and Associated Heat Transfer Technologies

    Microsoft Academic Search

    Luisa F. Cabeza; Cristian Sole; Albert Castell; Eduard Oro; Antoni Gil

    2012-01-01

    Thermal energy storage is a key component of solar power plants if dispatchability is required. On the other hand, although different systems and many materials are available, only a few plants in the world have tested thermal energy storage systems. Here, all materials considered in literature and\\/or used in real plants are listed, the different systems are described and analyzed,

  9. Review on thermal energy storage with phase change: materials, heat transfer analysis and applications

    Microsoft Academic Search

    Bele en Zalba; José M Mar??n; Luisa F. Cabeza; Harald Mehling

    2003-01-01

    Thermal energy storage in general, and phase change materials (PCMs) in particular, have been a main topic in research for the last 20 years, but although the information is quantitatively enormous, it is also spread widely in the literature, and difficult to find. In this work, a review has been carried out of the history of thermal energy storage with

  10. Effect of Heating Treatments, Processing Methods and Refrigerated Storage of Milk and Some Dairy Products on Lipids Oxidation

    E-print Network

    Meshref A. Al-rowaily

    Abstract: The effect of heating treatments (pasteurization and boiling), micro waving, processing steps and storage of milk and some locally produced dairy products (Brined white cheese (Nabulsi), Yogurt and Labaneh on chemical changes of milk lipids were evaluated. The Peroxide value (POV) p-anisidine value (p-AV), thiobarbituric acid (TBA), free fatty acid and totox were determined. The heating treatments of milk do significantly increase the levels of the oxidation parameters such as POV compared to those of fresh raw milk. The highest POV value (mEq O 2/kg fat) was for milk pasteurized at 95±1.0°C for 15 min (0.435), followed by milk heated at 63±1.0°C for 30 min (0.381), whereas, the lowest value was for milk pasteurized at 85±1.0°C for 16 sec (0.234). Key words: Fat oxidation, peroxide value, ultra-high temperature, thiobarbituric acid, D-anisidine value,

  11. Comprehensive Compressor Calorimeter Testing of Lower-GWP Alternative Refrigerants for Heat Pump and Medium Temperature Refrigeration Applications

    SciTech Connect

    Shrestha, Som S [ORNL] [ORNL; Sharma, Vishaldeep [ORNL] [ORNL; Abdelaziz, Omar [ORNL] [ORNL

    2014-01-01

    In response to environmental concerns raised by the use of refrigerants with high Global Warming Potential (GWP), the Air-Conditioning, Heating, and Refrigeration Institute (AHRI) has launched an industry-wide cooperative research program, referred to as the Low-GWP Alternative Refrigerants Evaluation Program (AREP), to identify and evaluate promising alternative refrigerants for major product categories. This paper reports one of the Oak Ridge National Laboratory (ORNL) contributions to AREP. It compares performance of alternative refrigerants to that of R-410A and R-404A for heat pump and medium temperature applications, respectively. The alternatives reported in this paper are: R-32, DR-5, and L-41a for R-410A and ARM-31a, D2Y-65, L-40, and a mixture of R-32 and R-134a for R-404A. All performance comparison tests were conducted using scroll compressors of ~1.85 tons (6.5 kW) cooling capacity. Tests were conducted over a range of combinations of saturation suction and saturation discharge temperatures for both compressors. The tests showed that, in general, energy efficiency ratio (EER) and cooling capacity of R-410A alternative refrigerants were slightly lower than that of the baseline refrigerant with a moderate increases in discharge temperature. On the other hand, R-404A alternative refrigerants showed relative performance dependence on saturation suction and saturation discharge temperatures and larger increases in discharge temperature than for the R-410A alternatives. This paper summarizes the relative performance of all alternative refrigerants compared to their respective baseline.

  12. Lunox storage and transfer system

    NASA Technical Reports Server (NTRS)

    1987-01-01

    This semester, efforts were concentrated on the design of the Lunox transfer line from the storage area to the launch site. Emphasis was placed on flow and heat transfer problems and their remedies by reducing the effect of radiation by selecting materials for storage tanks, transfer lines and insulation. The design for the storage tank was based on a medium sized Lunox production facility of 6,000 metric tons per year and the frequency of transportation of Lunox from lunar launch site to lower lunar orbit of four launches per month. The design included the selection of materials for cryogenic storage, insulation and radiation shielding. Lunox was pumped to the storage area near the launch site through a piping network designed for maximum mass flow rate with a minimum boil off. The entire network incorporated specially designed radiation shields made of material which was lightweight and low in secondary radiation.

  13. Microwave Heating Inactivates Shiga Toxin (Stx2) in Reconstituted Fat-Free Milk and Adversely Affects the Nutritional Value of Cell Culture Medium.

    PubMed

    Rasooly, Reuven; Hernlem, Bradley; He, Xiaohua; Friedman, Mendel

    2014-03-26

    Microwave exposure is a convenient and widely used method for defrosting, heating, and cooking numerous foods. Microwave cooking is also reported to kill pathogenic microorganisms that often contaminate food. In this study, we tested whether microwaves would inactivate the toxicity of Shiga toxin 2 (Stx2) added to 5% reconstituted fat-free milk administered to monkey kidney Vero cells. Heating of milk spiked with Stx2 in a microwave oven using a 10% duty cycle (cycle period of 30 s) for a total of 165 kJ energy or thermal heating (pasteurization), widely used to kill pathogenic bacteria, did not destroy the biological effect of the toxin in the Vero cells. However, conventional heating of milk to 95 °C for 5 min or at an increased microwave energy of 198 kJ reduced the Stx2 activity. Gel electrophoresis showed that exposure of the protein toxin to high-energy microwaves resulted in the degradation of its original structure. In addition, two independent assays showed that exposure of the cell culture medium to microwave energy of 198 kJ completely destroyed the nutritional value of the culture medium used to grow the Vero cells, possibly by damaging susceptible essential nutrients present in the medium. These observations suggest that microwave heating has the potential to destroy the Shiga toxin in liquid food. PMID:24669932

  14. Study of Applications of Solar Heating Systems with Seasonal Storage in China

    E-print Network

    Yu, G.; Zhao, X.; Chen, P.

    2006-01-01

    to partial load. 4. EFFECTS OF STORAGE VOLUME The volume of seasonal storage is an important parameter for the solar system. According to the usual routine[1], this paper uses the ratio of storage volume to collector area (Rv) to study its effects... on the whole system. Fig.5 gives the yearly temperature changes for different volume of tank. Rv is from 0.5 to 5. From Fig.3 we can see that the temperature in the tank rise to high level in short period when Rv is smaller than 3. If the Rv is more than 5...

  15. Analytical and experimental investigations of sodium heat pipes and thermal energy storage systems

    Microsoft Academic Search

    D. Jacobson

    1982-01-01

    Eight work elements for FY 1981 are reported on. A brief evaluation of the limits of arterial heat pipes is presented followed by the post life examination of two Inconel 600, sodium heat pipes which failed by pin hole corrosion through the evaporator. Nearly 12,000 hours of operation was sustained by one of the heat pipes prior to failure. A

  16. Optimization of radial fin tube heat exchangers for use in solar thermal storage systems. Final report

    Microsoft Academic Search

    J. B. Henderson; A. C. Caolo

    1983-01-01

    An experimental investigation was performed for free convection heat transfer from radial fin tube heat exchangers operating in water. Experimental heat transfer data were obtained as a function of the Rayleigh number for copper and aluminum fin tubes for two fin diameters and four fin spacings. The experimental data covered a Rayleigh number range of 1 to 10⁵. The experimental

  17. Synthesis and effect of electrode heat-treatment on the superior lithium storage performance of Co3O4 nanoparticles

    NASA Astrophysics Data System (ADS)

    Zhang, Jingjing; Huang, Tao; Yu, Aishui

    2015-01-01

    Single-crystal Co3O4 nanoparticles are produced via a novel lysine-assisted hydrothermal process. When used as anode materials for lithium-ion batteries, a heat-treatment process is first introduced to decrease the initial irreversible loss and enhance the cyclability of Co3O4 nanoparticle-based electrodes using a polyvinylidene fluoride (PVDF) binder. Heat-treated electrodes exhibit improved lithium storage properties relative to those that are unheated. In particular, Co3O4 electrodes heated at 200 °C have the highest capacity and best reversibility: 1000 mA h g-1 with 95.2% capacity retention after 170 cycles at a current density of 100 mA g-1. Even when cycled at a high rate of 1000 mA g-1, a reversible capacity up to 600 mA h g-1 can still be maintained after 500 cycles. These improvements are explained based on the results from thermal analysis, transmission electron microscopy, scanning electron microscopy, nanoscratch tests, and electrochemical impedance spectroscopy measurements. Heat treatment not only improves binder distribution and adhesion to both Co3O4 particles and the substrate but also ensures high interfacial conductivity and keeps the active material particles and carbon black electrically connected, thereby leading to superior electrochemical performance. The results suggest that the heat-treated Co3O4 electrode may be a promising anode for next-generation lithium-ion batteries.

  18. Design and analysis of a novel low-temperature solar thermal electric system with two-stage collectors and heat storage units

    Microsoft Academic Search

    Pei Gang; Li Jing; Ji Jie

    2011-01-01

    The proposed low-temperature solar thermal electric generation is based on the compound parabolic concentrator (CPC) of small concentration ratio and Organic Rankine Cycle (ORC). The technologies of CPC and ORC are analyzed, and feasibility of the system is demonstrated. In particular, two-stage collectors and heat storage units are adopted to improve heat collection efficiency. Organic fluid is preheated by flat

  19. On the heat removal characteristics and the analytical model of a thermal energy storage capsule using gelled Glauber's salt as the PCM

    Microsoft Academic Search

    Akio Saito; Seiji Okawa; Tadafumi Shintani; Ryuichiro Iwamoto

    2001-01-01

    An analytical and experimental investigation was performed on a heat removal process of the thermal energy storage (TES) capsule, using gelled Glauber's salt. Transient heat flux at the capsule wall was measured for various cooling conditions. In cases where the initial temperature was lower than the saturation temperature of the phase change material (PCM), numerical analyses were performed, approximating the

  20. Validation of a postfixation tissue storage and transport medium to preserve histopathology and molecular pathology analyses (total and phosphoactivated proteins, and FISH).

    PubMed

    Stumm, Michael M; Walker, Maja R; Stork, Caroline; Hanoteau, Noelle; Wagner, Urs; O'Reilly, Terence M

    2012-03-01

    Tumor biomarker studies are integral to oncology clinical trials but may yield artifactual results owing to variation in sample procurement and processing. Ethanol, 70% vol/vol, was validated as a sample transport medium using markers of the PI3K/Akt/mTOR pathway. BT474 tumor xenografts were excised and slices were immediately placed into formaldehyde and fixed for 24 hours. Fixed tissue slices were immediately processed into paraffin or transferred to 70% vol/vol ethanol and stored at room temperature for 1, 2, and 4 weeks before further processing. Freshly cut tissue sections were evaluated for pAKT(S473), HER2, pHER-2(Y1248), pS6(S235/236), and pS6(S240/244), Ki-67, and HER2 by fluorescence in situ hybridization and stained with H&E and Masson trichrome. No significant changes were observed when comparing samples stored in 70% ethanol for up to 4 weeks with immediately processed tissue. Ethanol, 70% vol/vol, provides a safe storage medium for formaldehyde-fixed tumor tissue, facilitating sample transport during multicenter clinical trials. PMID:22338055

  1. Quasi-steady state temperature distribution and numerical simulation on low Ste number latent heat storage thermal unit of solar thermal power generation

    NASA Astrophysics Data System (ADS)

    Huang, J.; Zhu, D. S.

    2010-03-01

    Solar thermal power generation systems, including direct steam generation, require isothermal energy storage systems for a saturation temperature range between 190° C and 310° C. One option to fulfill this requirement is the application of phase-change materials to absorb or release energy. In this paper, the basic concept of latent heat storage system is described, and a model of phase-change heat transfer of latent heat storage thermal unit for thermal energy storage system is built. Base on the practical thermo-physical properties of phase-change materials, Quasi-Steady State temperature distribution of phase-change heat transfer is analyzed under low Ste number. Numerical simulation (finite element method) taking account into the sensible heat is adopted and the results prove that the Quasi-Steady State temperature distribution obtained from theoretical is in good agreement with the results of numerical simulation. For a latent heat storage system with low Ste number characteristic, Quasi-Steady State solution can be used as the theoretical calculation foundation for engineering design.

  2. Solar energy storage via liquid filled cans - Test data and analysis

    NASA Technical Reports Server (NTRS)

    Saha, H.

    1978-01-01

    This paper describes the design of a solar thermal storage test facility with water-filled metal cans as heat storage medium and also presents some preliminary tests results and analysis. This combination of solid and liquid mediums shows unique heat transfer and heat contents characteristics and will be well suited for use with solar air systems for space and hot water heating. The trends of the test results acquired thus far are representative of the test bed characteristics while operating in the various modes.

  3. An experimental and numerical investigation of heat transfer during technical grade paraffin melting and solidification in a shell-and-tube latent thermal energy storage unit

    Microsoft Academic Search

    Anica Trp

    2005-01-01

    The latent thermal energy storage system of the shell-and-tube type during charging and discharging has been analysed in this paper. An experimental and numerical investigation of transient forced convective heat transfer between the heat transfer fluid (HTF) with moderate Prandtl numbers and the tube wall, heat conduction through the wall and solid–liquid phase change of the phase change material (PCM),

  4. Advanced latent heat of fusion thermal energy storage for solar power systems

    NASA Technical Reports Server (NTRS)

    Phillips, W. M.; Stearns, J. W.

    1985-01-01

    The use of solar thermal power systems coupled with thermal energy storage (TES) is being studied for both terrestrial and space applications. In the case of terrestrial applications, it was found that one or two hours of TES could shift the insolation peak (solar noon) to coincide with user peak loads. The use of a phase change material (PCM) is attractive because of the higher energy storage density which can be achieved. However, the use of PCM has also certain disadvantages which must be addressed. Proof of concept testing was undertaken to evaluate corrosive effects and thermal ratcheting effects in a slurry system. It is concluded that the considered alkali metal/alkali salt slurry approach to TES appears to be very viable, taking into account an elimination of thermal ratcheting in storage systems and the reduction of corrosive effects. The approach appears to be useful for an employment involving temperatures applicable to Brayton or Stirling cycles.

  5. An inverse problem of parameter estimation for time-fractional heat conduction in a composite medium using carbon-carbon experimental data

    NASA Astrophysics Data System (ADS)

    Zhuang, Qiao; Yu, Bo; Jiang, Xiaoyun

    2015-01-01

    In this paper, a time-fractional heat conduction problem is mathematically proposed for an experimental heat conduction process in a 3-layer composite medium. A numerical solution to the direct problem is obtained with finite difference method. In regard to the inverse problem, the optimal order of Caputo fractional derivative is estimated with Levenberg-Marquardt method. Comparing with the carbon-carbon experimental data, the results show that the time-fractional heat conduction model provides an effective and accurate simulation of the experimental data. The rationality of the proposed time-fractional model and validity of Levenberg-Marquardt method in solving the time-fractional inverse heat conduction problem are also manifested according to the results. By conducting the sensitivity analysis, the feasibility of the parameter estimation is further discussed.

  6. Environmental assessment for the relocation and storage of isotopic heat sources, Hanford Site, Richland, Washington

    SciTech Connect

    NONE

    1997-06-01

    As part of a bilateral agreement between the Federal Minister for Research and Technology of the Federal Republic of Germany (FRG) and the DOE, Pacific Northwest National Laboratory (PNNL) developed processes for the treatment and immobilization of high-level radioactive waste. One element of this bilateral agreement was the production of sealed isotopic heat sources. During the mid-1980s, 30 sealed isotopic heat sources were manufactured. The sources contain a total of approximately 8.3 million curies consisting predominantly of cesium-137 and strontium-90 with trace amounts of transuranic contamination. Currently, the sources are stored in A-Cell of the 324 Building. Intense radiation fields from the sources are causing the cell windows and equipment to deteriorate. Originally, it was not intended to store the isotopic heat sources for this length of time in A-cell. The 34 isotopic heat sources are classified as remote handled transuranic wastes. Thirty-one of the isotopic heat sources are sealed, and seals on the three remaining isotopic heat sources have not been verified. However, a decision has been made to place the remaining three isotopic heat sources in the CASTOR cask(s). The Washington State Department of Health (WDOH) has concurred that isotopic heat sources with verified seals or those placed into CASTOR cask(s) can be considered sealed (no potential to emit radioactive air emissions) and are exempt from WAC Chapter 246-247, Radiation Protection-Air Emissions.

  7. An Application of Solar Energy Storage in the Gas: Solar Heated Biogas Plants

    Microsoft Academic Search

    G. Kocar; A. Eryasar

    2007-01-01

    Temperature is an important factor that may affect the performance of anaerobic digestion. Therefore, biogas plants without heating system work only in warmer regions for the whole year. In regions with extreme temperature variations, for instance in Turkey, the biogas plant should be built with heating system. One of the methods is to use solar energy to increase the reactor

  8. Development of a carbon-heat hybrid ethylene scrubber for fresh horticultural produce storage purposes

    Microsoft Academic Search

    Domingo Martínez-Romero; Fabián Guillén; Salvador Castillo; Pedro Javier Zapata; María Serrano; Daniel Valero

    2009-01-01

    A scrubber to remove ethylene continuously from stored environments was developed. The device comprised a cartridge heater tightly joined to the activated carbon–1% Pd. The application of heat pulses led to an increase in ethylene oxidation and to auto-regeneration of the activated carbon. The efficacy of ethylene removal was higher with the number of heat pulses. Several combinations of exogenous

  9. Conventional versus storage phosphor-plate digital images to visualize the root canal system contrasted with a radiopaque medium.

    PubMed

    Naoum, Hani J; Chandler, Nicholas P; Love, Robert M

    2003-05-01

    The pulp tissue was removed from 20 mandibular first molar teeth using 2.5% NaOCl irrigation and hand files. The dried canals were infused with radiopaque contrast medium. Standardized conventional and Digora digital images were obtained of each tooth positioned in a dried mandible at 0- and 30-degree horizontal angulations. Three evaluators rated the image clarity of the 0- and 30-degree original, enhanced, three-dimensional, zoom, and reverse digital image modes as superior, equal, or inferior to corresponding 0- and 30-degree conventional radiographs. The ratings were compared using the Wilcoxon signed rank test. The original, three-dimensional, zoom, or reverse digital images were inferior to the conventional radiographs for clarity of canal anatomy. The enhanced digital images were not always inferior to the conventional radiographs and were the only images superior to the original digital images. Overall, evaluators rated the image clarity of root canal anatomy on conventional radiographs better than on Digora images. However, factors in the experimental design may have contributed to this result. PMID:12775009

  10. Effect of Heat Treatment Process on Mechanical Properties and Microstructure of a 9% Ni Steel for Large LNG Storage Tanks

    NASA Astrophysics Data System (ADS)

    Zhang, J. M.; Li, H.; Yang, F.; Chi, Q.; Ji, L. K.; Feng, Y. R.

    2013-12-01

    In this paper, two different heat treatment processes of a 9% Ni steel for large liquefied natural gas storage tanks were performed in an industrial heating furnace. The former was a special heat treatment process consisting of quenching and intercritical quenching and tempering (Q-IQ-T). The latter was a heat treatment process only consisting of quenching and tempering. Mechanical properties were measured by tensile testing and charpy impact testing, and the microstructure was analyzed by optical microscopy, transmission electron microscopy, and x-ray diffraction. The results showed that outstanding mechanical properties were obtained from the Q-IQ-T process in comparison with the Q-T process, and a cryogenic toughness with charpy impact energy value of 201 J was achieved at 77 K. Microstructure analysis revealed that samples of the Q-IQ-T process had about 9.8% of austenite in needle-like martensite, while samples of the Q-T process only had about 0.9% of austenite retained in tempered martensite.

  11. Helical flows of a heated generalized Oldroyd-B fluid subject to a time-dependent shear stress in porous medium

    NASA Astrophysics Data System (ADS)

    Li, Chunrui; Zheng, Liancun; Zhang, Yue; Ma, Lianxi; Zhang, Xinxin

    2012-12-01

    This paper presents an analysis for helical flows of a heated generalized Oldroyd-B fluid subject to a time-dependent shear stress in porous medium, where the motion is due to the longitudinal time-dependent shear stress and the oscillating velocity in boundary. The exact solutions are established by using the sequential fractional derivatives Laplace transform coupled with finite Hankel transforms in terms of generalized G function. Moreover, the effects of various parameters (relaxation time, fractional parameter, permeability and porosity) on the flow and heat transfer are analyzed in detail by graphical illustrations.

  12. Advanced latent heat of fusion thermal energy storage for solar power systems

    Microsoft Academic Search

    W. M. Phillips; J. W. Stearns

    1985-01-01

    The use of solar thermal power systems coupled with thermal energy storage (TES) is being studied for both terrestrial and space applications. In the case of terrestrial applications, it was found that one or two hours of TES could shift the insolation peak (solar noon) to coincide with user peak loads. The use of a phase change material (PCM) is

  13. Direct contact thermal energy storage system using Na 2CO 3·10H 2O solution

    Microsoft Academic Search

    Panut Mulyono

    2004-01-01

    The volumetric coefficient of heat transfer and the energy storage capacity in a direct contact thermal energy storage system using Na2CO3·10H2O solution as thermal energy storage medium have been investigated. Hot kerosene was used as a heat transfer fluid. The experiments were carried out by bubbling hot kerosene from the bottom of a column containing Na2CO3·10H2O solution. The column used

  14. A new method of efficient heat transfer and storage at very high temperatures

    NASA Technical Reports Server (NTRS)

    Shaw, D.; Bruckner, A. P.; Hertzberg, A.

    1980-01-01

    A unique, high temperature (1000-2000 K) continuously operating capacitive heat exchanger system is described. The system transfers heat from a combustion or solar furnace to a working gas by means of a circulating high temperature molten refractory. A uniform aggregate of beads of a glass-like refractory is injected into the furnace volume. The aggregate is melted and piped to a heat exchanger where it is sprayed through a counter-flowing, high pressure working gas. The refractory droplets transfer their heat to the gas, undergoing a phase change into the solid bead state. The resulting high temperature gas is used to drive a suitable high efficiency heat engine. The solidified refractory beads are delivered back to the furnace and melted to continue the cycle. This approach avoids the important temperature limitations of conventional tube-type heat exchangers, giving rise to the potential of converting heat energy into useful work at considerably higher efficiencies than currently attainable and of storing energy at high thermodynamic potential.

  15. Discrete ordinates interpolation method for radiative heat transfer problems in three-dimensional enclosures filled with non-gray or scattering medium

    Microsoft Academic Search

    Kihwan Kim; Euntaek Lee; Tae-Ho Song

    2008-01-01

    The discrete ordinates interpolation method (DOIM) is applied to three groups of problems of radiative heat transfer in three-dimensional rectangular enclosures containing non-gray or scattering medium. The original DOIM is first extended to a gray gas model using a new geometric interpolation scheme. It is applied to participating media for different scattering phase functions and optical thicknesses. For the non-gray

  16. An investigation into the thermal properties of selected sensible and latent heat storage materials

    E-print Network

    Wood, Stanley Clayton

    1982-01-01

    utilizing heat pipes was simulated by Yang and Lee [5). They used a finite difference analysis to model the system, which consisted of a PCM cylinder with a heat pipe in the center. One of the most important parameters to be determined in the behavior... largely analytical study of the transient response of a parafin PCM system to a step heat input. Water was utilized as the working fluid in the experimental analysis. There have been few experimental studies in this area of PCM. Lof and Howley [8...

  17. Numerical modeling of heat transfer in the fuel oil storage tank at thermal power plant

    NASA Astrophysics Data System (ADS)

    Kuznetsova, Svetlana A.

    2015-01-01

    Presents results of mathematical modeling of convection of a viscous incompressible fluid in a rectangular cavity with conducting walls of finite thickness in the presence of a local source of heat in the bottom of the field in terms of convective heat exchange with the environment. A mathematical model is formulated in terms of dimensionless variables "stream function - vorticity vector speed - temperature" in the Cartesian coordinate system. As the results show the distributions of hydrodynamic parameters and temperatures using different boundary conditions on the local heat source.

  18. The direct heat measurement of mechanical energy storage metal-organic frameworks.

    PubMed

    Rodriguez, Julien; Beurroies, Isabelle; Loiseau, Thierry; Denoyel, Renaud; Llewellyn, Philip L

    2015-04-01

    In any process, the heat exchanged is an essential property required in its development. Whilst the work related to structural transitions of some flexible metal-organic frameworks (MOFs) has been quantified and linked with potential applications such as molecular springs or shock absorbers, the heat related to such transitions has never been directly measured. This has now been carried out with MIL-53(Al) using specifically devised calorimetry experiments. We project the importance of these heats in devices such as molecular springs or dampers. PMID:25689834

  19. Efficiency and heat-removal factor for collector-storage walls

    SciTech Connect

    Alexander, R.

    1983-12-01

    Passive solar heating systems have been difficult to size, partly because they have been related to a solar savings fraction in the literature rather than to collector efficiency, which is a more widely used index of merit in active solar heating. More recently developed, the Unutilizability method represents a more traditional engineering approach, but is still difficult to apply and does not provide us with efficiency curves. This paper presents results from a study of collection and transfer efficiencies when the building either has large internal thermal mass or/and has a large heating load so that the indoor air temperature never departs very much from a fixed thermostat setting. A large number of computer simulations were made for the prototype solar heated room for a variety of wall materials and thicknesses, heat transfer coefficients and weather conditions. In order to correlate and explain the results, universal curves giving collector efficiency and heat removal factor are suggested based on steady-state theory. Agreement between theory and numerical results was found to be good. The theory, when applied to the prototype (unvented Trombe wall with double glazing and selective absorber coating), gave an estimated solar gain that was found to be consistent with an energy budget for the building for the January - May 1982 test period. Good agreement was also found with calculations employing the SLR method.

  20. Advanced thermal energy storage concept definition study for solar Brayton power plants. Volume II. Thermal energy storage system sizing computer program, July 1December 31, 1976. [Thermal energy storage sizing model

    Microsoft Academic Search

    Gintz

    1976-01-01

    This document describes the computer program used in conceptual studies of phase change and sensible heat thermal energy storage systems. The model assumes the phase change media is contained in a tube-in-bath configuration. The sensible heat medium is contained in high pressure tanks. The program has been used in conjunction with, but is not necessarily limited to, a high temperature,

  1. Steady boundary layer slip flow along with heat and mass transfer over a flat porous plate embedded in a porous medium.

    PubMed

    Aziz, Asim; Siddique, J I; Aziz, Taha

    2014-01-01

    In this paper, a simplified model of an incompressible fluid flow along with heat and mass transfer past a porous flat plate embedded in a Darcy type porous medium is investigated. The velocity, thermal and mass slip conditions are utilized that has not been discussed in the literature before. The similarity transformations are used to transform the governing partial differential equations (PDEs) into a nonlinear ordinary differential equations (ODEs). The resulting system of ODEs is then reduced to a system of first order differential equations which was solved numerically by using Matlab bvp4c code. The effects of permeability, suction/injection parameter, velocity parameter and slip parameter on the structure of velocity, temperature and mass transfer rates are examined with the aid of several graphs. Moreover, observations based on Schmidt number and Soret number are also presented. The result shows, the increase in permeability of the porous medium increase the velocity and decrease the temperature profile. This happens due to a decrease in drag of the fluid flow. In the case of heat transfer, the increase in permeability and slip parameter causes an increase in heat transfer. However for the case of increase in thermal slip parameter there is a decrease in heat transfer. An increase in the mass slip parameter causes a decrease in the concentration field. The suction and injection parameter has similar effect on concentration profile as for the case of velocity profile. PMID:25531301

  2. Steady Boundary Layer Slip Flow along with Heat and Mass Transfer over a Flat Porous Plate Embedded in a Porous Medium

    PubMed Central

    Aziz, Asim; Siddique, J. I.; Aziz, Taha

    2014-01-01

    In this paper, a simplified model of an incompressible fluid flow along with heat and mass transfer past a porous flat plate embedded in a Darcy type porous medium is investigated. The velocity, thermal and mass slip conditions are utilized that has not been discussed in the literature before. The similarity transformations are used to transform the governing partial differential equations (PDEs) into a nonlinear ordinary differential equations (ODEs). The resulting system of ODEs is then reduced to a system of first order differential equations which was solved numerically by using Matlab bvp4c code. The effects of permeability, suction/injection parameter, velocity parameter and slip parameter on the structure of velocity, temperature and mass transfer rates are examined with the aid of several graphs. Moreover, observations based on Schmidt number and Soret number are also presented. The result shows, the increase in permeability of the porous medium increase the velocity and decrease the temperature profile. This happens due to a decrease in drag of the fluid flow. In the case of heat transfer, the increase in permeability and slip parameter causes an increase in heat transfer. However for the case of increase in thermal slip parameter there is a decrease in heat transfer. An increase in the mass slip parameter causes a decrease in the concentration field. The suction and injection parameter has similar effect on concentration profile as for the case of velocity profile. PMID:25531301

  3. The effect of transpiration on coupled heat and mass transfer in mixed convection over a vertical plate embedded in a saturated porous medium

    SciTech Connect

    Yih, K.A. [Air Forces Inst. of Aeronautical Technology, Kaoshiuang (Taiwan, Province of China). Dept. of General Course] [Air Forces Inst. of Aeronautical Technology, Kaoshiuang (Taiwan, Province of China). Dept. of General Course

    1997-03-01

    Effect of transpiration velocity on the heat and mass transfer characteristics of mixed convection about a permeable vertical plate embedded in a saturated porous medium under the coupled effects of thermal and mass diffusion is numerically analyzed. The plate is maintained at a uniform temperature and species concentration with constant transpiration velocity. The transformed governing equations are solved by Keller box method. Numerical results for the local Nusselt number and local Sherwood number are presented. In general, it has been found for thermally assisted flow that the local surface heat and mass transfer rates increase owing to suction of fluid. This trend reversed for blowing of fluid. It is apparent that the Lewis number has a pronounced effect on the local Sherwood number than it does on the local Nusselt number. Increasing the Lewis number decreases (increases) the local heat (mass) transfer rate.

  4. Diurnal heat storage in direct-gain passive-solar buildings

    SciTech Connect

    Balcomb, J.D.; Neeper, D.A.

    1983-01-01

    This paper presents a simplified method for predicting temperature swings in direct-gain buildings. It is called the DHC method due to the use of a diurnal heat capacity (DHC). Diurnal heat capacity is a measure of the effective amount of heat stored during a sunny day and then released at night - the typical 24-hour diurnal cycle. This enables prediction of the maximum temperature swings experienced in the building and can be calculated using a single 24-hour harmonic. The advantage is that closed-form analytic solutions can be obtained for a variety of simple and layered-wall configurations. Higher harmonic components are accounted for by a correction factor. The method is suitable for us by hand or on a programmable calculator.

  5. Polymer alloys with balanced heat storage capacity and engineering attributes and applications thereof

    DOEpatents

    Soroushian, Parviz (Lansing, MI)

    2002-01-01

    A thermoplastic polymer of relatively low melt temperature is blended with at least one of thermosets, elastomers, and thermoplastics of relatively high melt temperature in order to produce a polymer blend which absorbs relatively high quantities of latent heat without melting or major loss of physical and mechanical characteristics as temperature is raised above the melting temperature of the low-melt-temperature thermoplastic. The polymer blend can be modified by the addition of at least one of fillers, fibers, fire retardants, compatibilisers, colorants, and processing aids. The polymer blend may be used in applications where advantage can be taken of the absorption of excess heat by a component which remains solid and retains major fractions of its physical and mechanical characteristics while absorbing relatively high quantities of latent heat.

  6. MIUS systems analysis: the effects of thermal energy storage and solid waste incineration options on MIUS cost and fuel consumption. [Water for thermal energy storage (TES)

    Microsoft Academic Search

    C. L. Segaser; W. R. Mixon

    1976-01-01

    Water is the preferred fluid for the conveyance of thermal energy between a MIUS district heating and cooling plant and the consumer. Because of its abundance, low cost, and unique thermal properties, water was also chosen as the thermal energy storage (TES) medium for MIUS in preference to one of the available latent-heat phase-change materials. This report presents the results

  7. Studies on heat capacities and thermal analysis of Li–Mg–N–H hydrogen storage system

    Microsoft Academic Search

    F. Xu; L. X. Sun; P. Chen; Y. N. Qi; J. Zhang; J. N. Zhao; Y. F. Liu; L. Zhang; Zhong Cao; D. W. Yang; J. L. Zeng; Y. Du

    2010-01-01

    The heat capacities of LiNH2 and Li2MgN2H2 were measured by a modulated differential scanning calorimetry (MDSC) over the temperature range from 223 to 473 K for the\\u000a first time. The value of heat capacity of LiNH2 is bigger than that of Li2MgN2H2 from 223 to 473 K. The thermodynamic parameters such as enthalpy (H–H\\u000a 298.15) and entropy (S–S\\u000a 298.15) versus 298.15 K were

  8. The role of heat storage in the soil in the energy balance of a greenhouse

    E-print Network

    Sadler, Edward John

    1978-01-01

    , CONCLUSIO. 'iS AND RECOfVIENDATI ONS. LITERATURE CITED. APPENDIX A. APPENDIX B. APPENDIX C. APPENDIX D. 37 39 41 45 45 60 76 BO B2 90 106 109 114 LIST OF TABLES TABLE Page Table of the optical properties governing the shortwave.../m . Price and Peart {1973) 2 developed a model of a waste heat utilization system including a greenhouse. They tested Walk r's (1965) model, judqed it accurate, and incorporated it into iheir model. However, they included the soil heat flux, (here Walker...

  9. Cumulative effects of heat exposure and storage conditions of Oxytocin-in-Uniject in rural Ghana: implications for scale up

    PubMed Central

    Mullany, Luke C; Newton, Sam; Afari-Asiedu, Samuel; Adiibokah, Edward; Agyemang, Charlotte T; Cofie, Patience; Brooke, Steve; Owusu-Agyei, Seth; Stanton, Cynthia K

    2014-01-01

    ABSTRACT Objective: Postpartum hemorrhage can be reduced substantially in home deliveries attended by community-based workers by using Oxytocin-in-Uniject (OIU) devices affixed with temperature-time indicators. We characterized the distribution of time to discard of these devices when stored under normal field conditions in Ghana. Methods: Two drug storage simulation studies were conducted in rural Ghana in 2011 and 2012. Devices were transported under refrigeration from manufacture (Argentina) to storage at the study site. Twenty-three field workers each stored at home (unrefrigerated) 25 OIU devices and monitored them daily to record: (1) time to transition from usable to unusable, and (2) continuous digital ambient temperature to determine heat exposure over the simulation period. Time to discard was estimated and compared with mean kinetic temperature exposure of the devices during the shipment and storage phases and with characteristics of the storage locations using Weibull regression models. We used the time to discard distributions in a Monte Carlo simulation to estimate wastage rates in a hypothetical program setting. Results: Time for shipment and transfer to long-term refrigerated storage and mean kinetic temperature during the shipment phase was 8.6 days/10.3°C and 13.4 days/12.1°C, for the first and second simulation studies, respectively. Median (range) time to discard when stored under field conditions (unrefrigerated) was 43 (6 to 59) days and 33 (14 to 50) days, respectively. Mean time to discard was 10.0 days shorter in the second simulation, during which mean kinetic temperature exposure was 3.9°C higher. Simulating a monthly distribution system and assuming typical usage, predicted wastage of product was less than 10%. Conclusion: The time to discard of devices was highly sensitive to small changes in temperature exposure. Under field conditions typical in rural Ghana, OIU packages will have a half-life of approximately 30 to 40 days based on the temperature monitor used during the study. Program managers will need to carefully consider variations in both ambient temperature and rate of use to allocate the appropriate supply level that will maximize coverage and minimize stock loss. PMID:25276588

  10. Oil/salt hydrate direct-contact heat-exchange experiments

    NASA Astrophysics Data System (ADS)

    Wright, J. D.; Bohn, M. S.; Barlow, R. S.

    1983-01-01

    A pilot-scale, direct-contact heat exchanger/storage column has been operated to determine heat transfer performance, storage capability, and operational difficulties associated with direct-contact heat exchange and storage with an oil heat transfer fluid and salt hydrate latent-heat storage medium. A fundamental analysis of the heat transfer mechanisms in the direct-contact process between oil droplets and the salt hydrate storage medium has shown that, for a typical storage system, the oil outlet temperature will be well within 30 C of the storage temperature. This implies that power output at the end of a storage cycle will be reduced by less than 30% relative to the beginning of a cycle. Experimental evidence agrees with these results, in that very small temperature differences between the oil outlet and the storage were measured. Since performance of the column is not heat-transfer limited, it can be designed to provide the storage capacity required. Operational problems which were investigated included proper distribution of the oil in the salt hydrate and salt carryover in the exit oil lines.

  11. Durability design of heated concrete structures. Methodology and application to long-term interim storage

    NASA Astrophysics Data System (ADS)

    Lagrave, H.; Ranc, G.; Gallé, C.; Durand, S.

    2006-11-01

    The operation of civil engineering structures subjected to thermal and mechanical loading has led the CEA to examine temperature-dependent variations in the concrete properties and the processes affecting the durability of these structures. A new approach has been undertaken to specify the thermal, hydric and mechanical history of these structures. This technical approach is based on three areas of research: material characterization, modelling to identify weaknesses in the structure and validation by experimental tests on heavily instrumented structures subjected to representative loads. The procedure adopted for long-term interim storage facilities [1, 2] can also be applied to other domains.

  12. Thermal Energy Storage in the Ground of a Greenhouse by the Polypropylene Capillary Heat Exchanger

    Microsoft Academic Search

    M. Lazâar; S. Koôli; M. Hazami; A. Farhat; A. Belghith

    The problem of temperature inversion is one of solar origin principal problems about which the cultures under shelters complain. Indeed, for the winter period, the temperature under greenhouse is very low at night and it is rather high during the day in summer. Consequently, the heating of the greenhouses is essential. In this work, we studied the advisability of using

  13. Thermal performance of submerged coil heat exchangers used in solar energy storage tanks

    Microsoft Academic Search

    D. E. Klett; D. Y. Goswami; M. T. Suad

    1984-01-01

    It can be seen from the test results that for the coil flow rate range of interest in solar DHW systems submersed coil heat exchangers can have effectiveness values as low as 0.3 for double-wall coils. This translates into a penalty of 12 to 15 percent for system performance. Inlet and outlet temperatures for the coil are easily measured. The

  14. Natural convection heat transfer to cylinders of phase change material used for thermal storage

    Microsoft Academic Search

    J. Pannu; G. Joglekar; P. A. Rice

    1980-01-01

    Calculations of the heat transfer and melting interface movement rates and temperature and velocity profiles of vertical and horizontal cylinders filled with Phase Change Materials (PCMs) are obtained and compared with experimental data. The experiments with paraffin wax-filled cylinders demonstrated melting rates faster than both pure conduction and natural convection mathematical models, with natural convection figures only 20% greater than

  15. Effect of nanoparticles on heat capacity of nanofluids based on molten salts as PCM for thermal energy storage.

    PubMed

    Chieruzzi, Manila; Cerritelli, Gian F; Miliozzi, Adio; Kenny, José M

    2013-01-01

    In this study, different nanofluids with phase change behavior were developed by mixing a molten salt base fluid (selected as phase change material) with nanoparticles using the direct-synthesis method. The thermal properties of the nanofluids obtained were investigated. These nanofluids can be used in concentrating solar plants with a reduction of storage material if an improvement in the specific heat is achieved. The base salt mixture was a NaNO3-KNO3 (60:40 ratio) binary salt. The nanoparticles used were silica (SiO2), alumina (Al2O3), titania (TiO2), and a mix of silica-alumina (SiO2-Al2O3). Three weight fractions were evaluated: 0.5, 1.0, and 1.5 wt.%. Each nanofluid was prepared in water solution, sonicated, and evaporated. Measurements on thermophysical properties were performed by differential scanning calorimetry analysis and the dispersion of the nanoparticles was analyzed by scanning electron microscopy (SEM). The results obtained show that the addition of 1.0 wt.% of nanoparticles to the base salt increases the specific heat of 15% to 57% in the solid phase and of 1% to 22% in the liquid phase. In particular, this research shows that the addition of silica-alumina nanoparticles has a significant potential for enhancing the thermal storage characteristics of the NaNO3-KNO3 binary salt. These results deviated from the predictions of the theoretical model used. SEM suggests a greater interaction between these nanoparticles and the salt. PMID:24168168

  16. Effect of nanoparticles on heat capacity of nanofluids based on molten salts as PCM for thermal energy storage

    PubMed Central

    2013-01-01

    In this study, different nanofluids with phase change behavior were developed by mixing a molten salt base fluid (selected as phase change material) with nanoparticles using the direct-synthesis method. The thermal properties of the nanofluids obtained were investigated. These nanofluids can be used in concentrating solar plants with a reduction of storage material if an improvement in the specific heat is achieved. The base salt mixture was a NaNO3-KNO3 (60:40 ratio) binary salt. The nanoparticles used were silica (SiO2), alumina (Al2O3), titania (TiO2), and a mix of silica-alumina (SiO2-Al2O3). Three weight fractions were evaluated: 0.5, 1.0, and 1.5 wt.%. Each nanofluid was prepared in water solution, sonicated, and evaporated. Measurements on thermophysical properties were performed by differential scanning calorimetry analysis and the dispersion of the nanoparticles was analyzed by scanning electron microscopy (SEM). The results obtained show that the addition of 1.0 wt.% of nanoparticles to the base salt increases the specific heat of 15% to 57% in the solid phase and of 1% to 22% in the liquid phase. In particular, this research shows that the addition of silica-alumina nanoparticles has a significant potential for enhancing the thermal storage characteristics of the NaNO3-KNO3 binary salt. These results deviated from the predictions of the theoretical model used. SEM suggests a greater interaction between these nanoparticles and the salt. PMID:24168168

  17. Extended development of a sodium hydroxide thermal energy storage module

    NASA Technical Reports Server (NTRS)

    Rice, R. E.; Rowny, P. E.; Cohen, B. M.

    1980-01-01

    The post-test evaluation of a single heat exchanger sodium hydroxide thermal energy storage module for use in solar electric generation is reported. Chemical analyses of the storage medium used in the experimental model are presented. The experimental verification of the module performance using an alternate heat transfer fluid, Caloria HT-43, is described. Based on these results, a design analysis of a dual heat exchanger concept within the storage module is presented. A computer model and a reference design for the dual system (storage working fluid/power cycle working fluid) were completed. The dual system is estimated to have a capital cost of approximately one half that of the single heat exchanger concept.

  18. Analysis of the influence of operating conditions and geometric parameters on heat transfer in water-paraffin shell-and-tube latent thermal energy storage unit

    Microsoft Academic Search

    Anica Trp; Kristian Lenic; Bernard Frankovic

    2006-01-01

    A transient heat transfer phenomenon during charging and discharging of the shell-and-tube latent thermal energy storage system has been analysed in this paper. The mathematical model, regarding the conjugate problem of transient forced convection and solid–liquid phase change heat transfer based on the enthalpy formulation, has been presented. A fully implicit two-dimensional control volume FORTRAN computer code has been developed

  19. Variation in Oat Groats Due to Variety, Storage and Heat Treatment. I: Phenolic Compounds

    Microsoft Academic Search

    L. H. Dimberg; E. L. Molteberg; R. Solheim; W. Frølich

    1996-01-01

    Low molecular weight phenolic compounds present in heat processed oats (Avena sativaL) were analysed. The oat grains were of three varieties (Kapp, Mustang and Svea), stored at different relative humidities (30, 55 or 80%) and periods (3·5 or 15·5 months) and processed with or without hulls. Eleven UV-absorbing compounds detected by High Performance Liquid Chromatography were subjected to univariate and

  20. Numerical analysis of flow and heat transfer in the VAFB LOX storage Dewar tank

    NASA Technical Reports Server (NTRS)

    Tam, L. T.; Singhal, A. K.

    1984-01-01

    The present report describes numerical simulation of three-dimensional transient distributions of velocity and temperature of liquid oxygen (LOX) in the LOX Dewar tank of Vendenberg Air Force Base (VAFB). The present analyses cover the replenish time period only. Four test cases have been considered. For all four cases, the input boundary conditions are comprised of LOX facility heat loads, drain flow rates, recirculation flow rates and dewar heating. All the quantities are prescribed as functions of time. The first two test cases considered sensitivity of results to the computational grid. In Case 3, system heat load was changed, while in Case 4, a lower LOX level was specified. Cases 1 and 2 showed that the temperatures were not sensitive to the grid refinement. This provided a basic check on the numerical model. Cases 3 and 4 showed that the thermal boundary layer motion near the tank surface becomes more significant at the late time, e.g., 5 1/2 hours from replenish start. Comparison between results of Cases 3 and 4 showed, as expected, that the smaller initial LOX volume given in Case 4, results in higher temperature level. All calculated velocity and temperature distributions were found to be plausible.

  1. Structural assessment of a Space Station solar dynamic heat receiver thermal energy storage canister

    NASA Technical Reports Server (NTRS)

    Tong, M. T.; Kerslake, T. W.; Thompson, R. L.

    1988-01-01

    This paper assesses the structural performance of a Space Station thermal energy storage (TES) canister subject to orbital solar flux variation and engine cold start-up operating conditions. The impact of working fluid temperature and salt-void distribution on the canister structure are assessed. Both analytical and experimental studies were conducted to determine the temperature distribution of the canister. Subsequent finite-element structural analyses of the canister were performed using both analytically and experimentally obtained temperatures. The Arrhenius creep law was incorporated into the procedure, using secondary creep data for the canister material, Haynes-188 alloy. The predicted cyclic creep strain accumulations at the hot spot were used to assess the structural performance of the canister. In addition, the structural performance of the canister based on the analytically-determined temperature was compared with that based on the experimentally-measured temperature data.

  2. Structural assessment of a space station solar dynamic heat receiver thermal energy storage canister

    NASA Technical Reports Server (NTRS)

    Thompson, R. L.; Kerslake, T. W.; Tong, M. T.

    1988-01-01

    The structural performance of a space station thermal energy storage (TES) canister subject to orbital solar flux variation and engine cold start up operating conditions was assessed. The impact of working fluid temperature and salt-void distribution on the canister structure are assessed. Both analytical and experimental studies were conducted to determine the temperature distribution of the canister. Subsequent finite element structural analyses of the canister were performed using both analytically and experimentally obtained temperatures. The Arrhenius creep law was incorporated into the procedure, using secondary creep data for the canister material, Haynes 188 alloy. The predicted cyclic creep strain accumulations at the hot spot were used to assess the structural performance of the canister. In addition, the structural performance of the canister based on the analytically determined temperature was compared with that based on the experimentally measured temperature data.

  3. Solid state phase change materials for thermal energy storage in passive solar heated buildings

    SciTech Connect

    Benson, D.K.; Christensen, C.

    1983-11-01

    A set of solid state phase change materials was evaluated for possible use in passive solar thermal energy storage systems. The most promising materials are organic solid solutions of pentaerythritol, pentaglycerine and neopentyl glycol. Solid solution mixtures of these compounds can be tailored so that they exhibit solid-to-solid phase transformations at any desired temperature within the range from less than 25 deg to 188 deg. Thermophysical properties such as thermal conductivity, density and volumetric expansion were measured. Computer simulations were used to predict the performance of various Trombe wall designs incorporating solid state phase change materials. Optimum performance was found to be sensitive to the choice of phase change temperatures and to the thermal conductivity of the phase change material. A molecular mechanism of the solid state phase transition is proposed and supported by infrared spectroscopic evidence.

  4. Antimicrobial activity of plant compounds against Salmonella Typhimurium DT104 in ground pork and the influence of heat and storage on the activity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objectives of this study were to investigate the influence of heat (70oC for 5 min) and cold-storage (4oC up to 7 days) on the effectiveness of oregano and cinnamon essential oils and powdered olive and apple extracts against Salmonella Typhimurium DT104 in ground pork and to evaluate the activi...

  5. Thermal performance analysis of a flat slab phase change thermal storage unit with liquid-based heat transfer fluid for cooling applications

    Microsoft Academic Search

    Ming Liu; Frank Bruno; Wasim Saman

    2011-01-01

    This paper presents the results of a thermal performance analysis of a phase change thermal storage unit. The unit consists of several parallel flat slabs of phase change material (PCM) with a liquid heat transfer fluid (HTF) flowing along the passages between the slabs. A validated numerical model developed previously to solve the phase change problem in flat slabs was

  6. Free convection about a vertical flat plate embedded in a porous medium with application to heat transfer from a dike

    Microsoft Academic Search

    Ping Cheng; W. J. Minkowycz

    1977-01-01

    An analysis is made for steady free convection about a vertical flat plate embedded in a saturated porous medium at high Rayleigh numbers. Within the framework of boundary layer approximations, similarity solutions are obtained for a class of problems where wall temperature varies as xlambda, i.e., a power function of distance from the origin where wall temperature begins to deviate

  7. Phase Change Characteristics of a Nanoemulsion as a Latent Heat Storage Material

    NASA Astrophysics Data System (ADS)

    Fumoto, Koji; Sato, Noriaki; Kawaji, Masahiro; Kawanami, Tsuyoshi; Inamura, Takao

    2014-10-01

    The primary objective of this study was to investigate the fundamental phase change characteristics of a nanoemulsion using differential scanning calorimetry (DSC). Tetradecane, which has a slightly higher melting point than water, was utilized as the phase change material for the nanoemulsion. The melting point of the nanoemulsion, the melting peak temperature, and latent heat were examined in detail. Regarding the fundamental phase change characteristics of the nanoemulsion, it was found that its phase change characteristics were strongly affected by the temperature-scanning rate of the DSC. Moreover, it was confirmed that the phase change behavior does not change with repeated solidification and melting.

  8. Effect of Heat Input on Microstructural Changes and Corrosion Behavior of Commercially Pure Titanium Welds in Nitric Acid Medium

    NASA Astrophysics Data System (ADS)

    Ravi Shankar, A.; Gopalakrishnan, G.; Balusamy, V.; Kamachi Mudali, U.

    2009-11-01

    Commercially pure titanium (Ti) has been selected for the fabrication of dissolver for the proposed fast reactor fuel reprocessing plant at Kalpakkam, India. In the present investigation, microstructural changes and corrosion behavior of tungsten inert gas (TIG) welds of Ti grade-1 and grade-2 with different heat inputs were carried out. A wider heat affected zone was observed with higher heat inputs and coarse grains were observed from base metal toward the weld zone with increasing heat input. Fine and more equiaxed prior ? grains were observed at lower heat input and the grain size increased toward fusion zone. The results indicated that Ti grade-1 and grade-2 with different heat inputs and different microstructures were insensitive to corrosion in liquid, vapor, and condensate phases of 11.5 M nitric acid tested up to 240 h. The corrosion rate in boiling liquid phase (0.60-0.76 mm/year) was higher than that in vapor (0.012-0.039 mm/year) and condensate phases (0.04-0.12 mm/year) of nitric acid for Ti grade-1 and grade-2, as well as for base metal for all heat inputs. Potentiodynamic polarization experiment carried out at room temperature indicated higher current densities and better passivation in 11.5 M nitric acid. SEM examination of Ti grade-1 welds for all heat inputs exposed to liquid phase after 240 h showed corrosion attack on the surface, exposing Widmanstatten microstructure containing acicular alpha. The continuous dissolution of the liquid-exposed samples was attributed to the heterogeneous microstructure and non-protective passive film formation.

  9. Microbial activity in argillite waste storage cells for the deep geological disposal of French bituminous medium activity long lived nuclear waste: Impact on redox reaction kinetics and potential

    NASA Astrophysics Data System (ADS)

    Albrecht, A.; Leone, L.; Charlet, L.

    2009-04-01

    Micro-organisms are ubiquitous and display remarkable capabilities to adapt and survive in the most extreme environmental conditions. It has been recognized that microorganisms can survive in nuclear waste disposal facilities if the required major (P, N, K) and trace elements, a carbon and energy source as well as water are present. The space constraint is of particular interest as it has been shown that bacteria do not prosper in compacted clay. An evaluation of the different types of French medium and high level waste, in a clay-rich host rock storage environment at a depth between 500 and 600 m, has shown that the bituminous waste is the most likely candidate to accommodate significant microbial activity. The waste consists of a mixture of bitumen (source of bio-available organic matter and H2 as a consequence of its degradation and radiolysis) and nitrates and sulphates kept in a stainless steel container. The assumption, that microbes only have an impact on reaction kinetics needs to be reassessed in the case where nitrates and sulphates are present since both are known not to react at low temperatures without bacterial catalysis. The additional impact of both oxy-anions and their reduced species on redox conditions, radionuclide speciation and mobility gives this evaluation their particular relevance. Storage architecture proposes four primary waste containers positioned into armoured cement over packs and placed with others into the waste storage cell itself composed of a cement mantle enforcing the argillite host rock, the latter being characterized by an excavation damaged zone constricted both in space and in time and a pristine part of 60 m thickness. Bacterial activity within the waste and within the pristine argillite is disregarded because of the low water activity (< 0.7) and the lack of space, respectively. The most probable zones of microbial activity, those likely to develop sustainable biofilms are within the interface zones. A major restriction for the initial development of microbial colonies is the high pH controlled by the cement solution. Archea are able to survive at high pH, when hydrogen gas is available as an energy sources; they are therefore likely candidates for an initial biofilm formation. It can not be excluded that other micro-organisms such as fungi may develop as well in such conditions. It also needs to be evaluated how conditions change with time and how this affects microbial ecology. The following is known about the impact of microbes on the waste cell biogeochemistry: • enhancement of redox reaction kinetics (particularly involving nitrates, sulphate, selenate, pertechnetate, organic matter and H2), thus a faster move towards reducing conditions, important to guarantee the low mobility of critical RN, • increased retardation of mobile RN in biofilms (i.e. adsorption on microbial cell surfaces and products of possible biomineralization); complexation by embedded extracellular polymeric substances, • secretion of organic substances (i.e siderophores) known to complex RN and to enhance their mobility, • biodegradation of dissolved organic substances, such as those released form the waste (organic acids) or generated by microbes, • production of CO2 or other gases that may affect cement integrity. Quantification of microbial activity has been implemented into biogeochemical models but the important parameters describing their evolution and metabolism in the real system (ecology, mass, energy sources, metabolites) need to be obtained via specific empirical studies. Such studies require a particular trans-disciplinary approach that brings together the competence of chemical and environmental engineers, microbiologists and system modellers.

  10. [Kinetics of furfural formation as related to heating, concentration and storage of orange juices and concentrates].

    PubMed

    Herrmann, J; Partassidou, V

    1979-01-01

    According to studies on an orange concentrate diluted back with distilled water to the desired extract content, the formation of furfural follows the pattern of a consequent reaction. After the induction period, the reaction curve takes a linear course cooresponding to a reaction of a zero order. The temperature dependence of the resultant reaction constant k obeys the ARRHENIUS equation and yields the same energy of activation for all the extract contents under investigation. This is a case of specific acid catalysis, because the reaction velocity is directly proportional to the hydronium ion activity. On a semilogarithmic scale, the dependence of the k values of the extract contents of the concentrates and of the re-constituted juice can be presented for various temperatures in the form of parallels. According to the literature, the amount of the furfural produced correlates with the quality of the orange juices and concentrates. Consequently, this amount might be used as an indicator in evaluating quality deteriorations due to unsuitable manufacturing and storage on the one hand, and for the computation and optimization of the manufacturing processes and parameters on the other hand. PMID:471035

  11. SERI Solar Energy Storage Program: FY 1984

    NASA Astrophysics Data System (ADS)

    Luft, W.; Bohn, M.; Copeland, R. J.; Kreith, F.; Nix, R. G.

    1985-02-01

    The activities of the Solar Energy Research Institute's Solar Energy Research Institute's Solar Energy Storage Program during its sixth year are summarized. During FY 1984 a study was conducted to identify the most promising high-temperature containment concepts considering corrosion resistance, material strength at high temperature, reliability of performance, and cost. Of the two generic types of high-temperature thermal storage concepts, the single-tank system was selected using a two-medium approach to the thermocline maintenance. This concept promises low costs, but further research is required. A conceptual design for a sand-to-air direct-contact heat exchanger was developed using dual-lock hoppers to introduce the sand into the fluidized-bed exchanger, and using cyclones to remove sand particles from the output air stream. Preliminary cost estimates indicate heat exchanger subsystem annual levelized costs of about $4/GJ with compressor costs of an additional $0.75/GJ. An economic analysis comparing sensible and latent heat storage for nitrate and carbonate salts with solely sensible heat storage showed 3%-21% cost savings with combined sensible and latent heat storage.

  12. Hydromagnetic simultaneous heat and mass transfer by mixed convection from a vertical plate embedded in a stratified porous medium with thermal dispersion effects

    NASA Astrophysics Data System (ADS)

    Chamkha, A. J.; Khaled, A.-R. A.

    The problem of steady, laminar, hydromagnetic simultaneous heat and mass transfer by mixed convection flow over a vertical plate embedded in a uniform porous medium with a stratified free stream and taking into account the presence of thermal dispersion is investigated for the case of power-law variations of both the wall temperature and concentration. Certain transformations are employed to transform the governing differential equations to a local similarity form. The transformed equations are solved numerically by an efficient implicit, iterative, finite-difference scheme. The obtained results are checked against previously published work on special cases of the problem and are found to be in excellent agreement. A parametric study illustrating the influence of the magnetic field, porous medium inertia effects, heat generation or absorption, lateral wall mass flux, concentration to thermal buoyancy ratio, and the Lewis number on the fluid velocity, temperature and concentration as well as the Nusselt and the Sherwood numbers is conducted. The results of this parametric study is shown graphically and the physical aspects of the problem are discussed.

  13. Hyperthermia during Olympic triathlon: influence of body heat storage during the swimming stage.

    PubMed

    Kerr, C G; Trappe, T A; Starling, R D; Trappe, S W

    1998-01-01

    The purpose of this project was to determine whether mild heat stress induced by wearing a wet suit while swimming in relatively warm water (25.4 +/- 0.1 degrees C) increases the risk of heat injury during the cycling and running stages of an International distance triathlon in a hot and humid environment (32 degrees C and 65% RH). Five male triathletes randomly completed two simulated triathlons (swim = 30 min; bike = 40 km; run = 10 km) in the laboratory using a swimming flume, cycle ergometer, and running treadmill. In both trials, all conditions were identical, except for the swimming portion in which a neoprene wet suit was worn during one trial (WS) and a swimming suit during the other (SS). The swim portion consisted of a 30-min standardized swim in which oxygen consumption (VO2) was replicated, regardless of WS or SS. During the cycling and running stages, however, the subjects were asked to complete the distances as fast as possible. Core temperature (Tc) was not significantly different between the SS and WS trials at any time point during the triathlon. However, mean skin temperature (Tsk) and mean body temperature (Tb) were higher (P < 0.05) in the WS at 15 (Tsk = +4.1 degrees C, Tb = +1.5 degrees C) and 30 min (Tsk = +4 degrees C, Tb = +1.6 degrees C) of the swim. These Tsk and Tb differences were eliminated by 15 min of the cycling stage and remained similar (P > 0.05) through the end of the triathlon. Moreover, there were no differences (P > 0.05) in VO2, heart rate (HR), rating of perceived exertion (RPE), or thermal sensation (TS) between the WS and SS. Additionally, no significant differences were found in cycling (SS = 1:14:46 +/- 2:48 vs WS = 1:14:37 +/- 2:54 min), running (SS = 55:40 +/- 1:49 vs WS = 57:20 +/- 4:00 min), or total triathlon times (SS = 2:40:26 +/- 1:58 vs WS = 2:41:57 +/- 1:37 min). These data indicate that wearing a wet suit during the swimming stage of an international distance triathlon in 25.4 degrees C water does not adversely affect the thermoregulatory responses of the triathlete on the subsequent cycling and running stages. PMID:9475650

  14. Preparation and characterization of novel anion phase change heat storage materials.

    PubMed

    Hong, Wei; Lil, Qingshan; Sun, Jing; Di, Youbo; Zhao, Zhou; Yu, Wei'an; Qu, Yuan; Jiao, TiFeng; Wang, Guowei; Xing, Guangzhong

    2013-10-01

    In this paper, polyurethane phase change material was successfully prepared with TDI with BDO for hard segments and PEG for soft segments. Moreover, based on this the solid-solid phase change material, A-PCM1030 which can release anions was prepared with the successful addition of anion additives A1030 for the first time. Then the test of the above material was conducted utilizing FT-IR, DSC, TEM, WAXD and Air Ion Detector. The Results indicated that the polyurethane phase change material possesses excellent thermal stability since there was no appearance of liquid leakage and phase separation after 50 times warming-cooling thermal cycles. It also presented reversibility on absorbing and releasing heat. In addition, adding a little A1030 can increase the thermal stability and reduce phase transition temperatures, as well as reduce the undercooling of the polyurethane phase change material. In addition, the anion test results suggested that the supreme amount of anion released by A-PCM1030 could reach 2510 anions/cm3 under dynamic conditions, which is beneficial for human health. PMID:24245138

  15. Initial findings: The integration of water loop heat pump and building structural thermal storage systems

    SciTech Connect

    Marseille, T.J.; Johnson, B.K.; Wallin, R.P.; Chiu, S.A.; Crawley, D.B.

    1989-01-01

    This report is one in a series of reports describing research activities in support of the US Department of Energy (DOE) Commercial Building System Integration Research Program. The goal of the program is to develop the scientific and technical basis for improving integrated decision-making during design and construction. Improved decision-making could significantly reduce buildings' energy use by the year 2010. The objectives of the Commercial Building System Integration Research Program are: to identify and quantify the most significant energy-related interactions among building subsystems; to develop the scientific and technical basis for improving energy related interactions in building subsystems; and to provide guidance to designers, owners, and builders for improving the integration of building subsystems for energy efficiency. The lead laboratory for this program is the Pacific Northwest Laboratory. A wide variety of expertise and resources from industry, academia, other government entities, and other DOE laboratories are used in planning, reviewing and conducting research activities. Cooperative and complementary research, development, and technology transfer activities with other interested organizations are actively pursued. In this report, the interactions of a water loop heat pump system and building structural mass and their effect on whole-building energy performance is analyzed. 10 refs., 54 figs., 1 tab.

  16. Radiant heat testing of the H1224A shipping/storage container

    SciTech Connect

    Harding, D.C.; Bobbe, J.G.; Stenberg, D.R.; Arviso, M.

    1994-05-01

    H1224A weapons containers have been used for years by the Departments of Energy and Defense to transport and store W78 warhead midsections. Although designed to protect the midsections only from low-energy impacts, a recent transportation risk assessment effort has identified a need to evaluate the container`s ability to protect weapons in more severe accident environments. Four radiant heat tests were performed: two each on an H1224A container (with a Mk12a Mod 6c mass mock-up midsection inside) and two on a low-cost simulated H1224A container (with a hollow Mk12 aeroshell midsections inside). For each unit tested, temperatures were recorded at numerous points throughout the container and midsection during a 4-hour 121{degrees}C (250{degrees}F) and 30-minute 1010{degrees}C (1850{degrees}F) radiant environment. Measured peak temperatures experienced by the inner walls of the midsections as a result of exposure to the high-temperature radiant environment ranged from 650{degrees} C to 980{degrees} C (1200{degrees} F to 1800{degrees}F) for the H1224A container and 770 {degrees} to 990 {degrees}C (1420{degrees} F to 1810{degrees}F) for the simulated container. The majority of both containers were completely destroyed during the high-temperature test. Temperature profiles will be used to benchmark analytical models and predict warhead midsection temperatures over a wide range of the thermal accident conditions.

  17. Numerical modeling of heat and mass transfer in porous medium during combined hot air, infrared and microwaves drying

    Microsoft Academic Search

    P. Salagnac; P. Glouannec; D. Lecharpentier

    2004-01-01

    This study deals with numerical modeling of the hygrothermal behaviour of a rectangular-shaped porous material during combined drying. This material is submitted on its upper side both a hot air flow as well as infrared and microwave radiations. The one-dimensional physical model describing heat and mass transfers allows accessing temperature, moisture content and pressure fields. Energy inputs induced by the

  18. Hot Thermal Storage/Selective Energy System Reduces Electric Demand for Space Cooling As Well As Heating in Commercial Application

    E-print Network

    Meckler, G.

    1985-01-01

    Based on an experimental residential retrofit incorporating thermal storage, and extensive subsequent modeling, a commercial design was developed and implemented to use hot thermal storage to significantly reduce electric demand and utility energy...

  19. Effect of sporulation medium on wet-heat resistance and structure of Alicyclobacillus acidoterrestris DSM 3922-type strain spores and modeling of the inactivation kinetics in apple juice.

    PubMed

    Molva, Celenk; Baysal, Ayse Handan

    2014-10-17

    Alicyclobacillus acidoterrestris is a spoilage bacterium in fruit juices leading to high economic losses. The present study evaluated the effect of sporulation medium on the thermal inactivation kinetics of A. acidoterrestris DSM 3922 spores in apple juice (pH3.82±0.01; 11.3±0.1 °Brix). Bacillus acidocaldarius agar (BAA), Bacillus acidoterrestris agar (BATA), malt extract agar (MEA), potato dextrose agar (PDA) and B. acidoterrestris broth (BATB) were used for sporulation. Inactivation kinetic parameters at 85, 87.5 and 90°C were obtained using the log-linear model. The decimal reduction times at 85°C (D85°C) were 41.7, 57.6, 76.8, 76.8 and 67.2min; D87.5°C-values were 22.4, 26.7, 32.9, 31.5, and 32.9min; and D90°C-values were 11.6, 9.9, 14.7, 11.9 and 14.1min for spores produced on PDA, MEA, BATA, BAA and BATB, respectively. The estimated z-values were 9.05, 6.60, 6.96, 6.15, and 7.46, respectively. The present study suggests that the sporulation medium affects the wet-heat resistance of A. acidoterrestris DSM 3922 spores. Also, the dipicolinic acid content (DPA) was found highest in heat resistant spores formed on mineral containing media. After wet-heat treatment, loss of internal volume due to the release of DPA from spore core was observed by scanning electron microscopy. Since, there is no standardized media for the sporulation of A. acidoterrestris, the results obtained from this study might be useful to determine and compare the thermal resistance characteristics of A. acidoterrestris spores in fruit juices. PMID:25129530

  20. H2O heating in molecular clouds - Line transfer and thermal balance in a warm dusty medium

    NASA Technical Reports Server (NTRS)

    Takahashi, T.; Silk, J.; Hollenbach, D. J.

    1983-01-01

    An investigation is undertaken into the possibility of the heating of molecular gas through collisions with radiatively pumped H2O, in the context of the overall thermal balance of optically thick molecular clouds with embedded sources. In order to solve the line transfer equation, which includes warm dust grains, an extended method of escape probability approximation is developed in which the equilibrium gas temperature arises from the balance of heating by cosmic ray ionization of H2, and by collisions with warm dust grains and radiatively pumped H2O molecules against cooling by collisions with CO and C I. The equilibrium gas temperature for a given dust temperature strongly depends on the efficiency of the cooling species, and is therefore most sensitive to the cloud optical depth. It is less dependent, in decreasing order, on H2O abundance, gas density, and velocity dispersion.

  1. Investigation of the active medium of a gasdynamic laser with nitrogen heating in a finite-volume chamber

    Microsoft Academic Search

    K. P. Alekseev; G. V. Vstovskii; V. M. Glazenkov; N. M. Gorshunov; Yu P Neshchimenko

    1984-01-01

    An investigation was made of a variant of a mixing gasdynamic laser with nitrogen heating by an electric discharge in a 0.7-liter chamber. The time dependences of the gain K0(t) were determined for two rotational transitions in the 001–100 band of the CO2 molecule. When nozzle arrays with mixing of fluxes in an expanding channel were used, the values of

  2. BRIEF COMMUNICATIONS: Investigation of the active medium of a gasdynamic laser with nitrogen heating in a finite-volume chamber

    Microsoft Academic Search

    K. P. Alekseev; G. V. Vstovskii; V. M. Glazenkov; N. M. Gorshunov; Yu P. Neshchimenko

    1984-01-01

    An investigation was made of a variant of a mixing gasdynamic laser with nitrogen heating by an electric discharge in a 0.7-liter chamber. The time dependences of the gain K0(t) were determined for two rotational transitions in the 001-100 band of the CO2 molecule. When nozzle arrays with mixing of fluxes in an expanding channel were used, the values of

  3. Heat treatment effects on the microstructure and mechanical properties of a medium manganese steel (0.2C-5Mn)

    Microsoft Academic Search

    H. F. Xu; J. Zhao; W. Q. Cao; J. Shi; C. Y. Wang; J. Li; H. Dong

    Microstructures and mechanical properties of 0.2C-5Mn steel processed under different heat treatment conditions were examined by scanning electron microscopy (SEM), Transmission electron microscopy (TEM) and x-rays diffraction (XRD). It was found that high temperature austenization (above Ac3) resulted in a full martensite structure after quenching, which gradually transformed into the ferrite\\/austenite duplex structure during the following annealing process. However, austenization

  4. Study of stream wise transverse magnetic fluid flow with heat transfer around an obstacle embedded in a porous medium

    NASA Astrophysics Data System (ADS)

    Rashidi, S.; Dehghan, M.; Ellahi, R.; Riaz, M.; Jamal-Abad, M. T.

    2015-03-01

    A mathematical model for two-dimensional fluid flow under the influence of stream wise transverse magnetic fields in laminar regime is simulated in this study. Heat transfer past a square diamond shaped porous obstacle is also taken into account. The attention is focused to investigate the effects of intensity and direction of magnetic field, Darcy and Reynolds numbers on the mechanism of convective heat transfer and flow structures. The Darcy-Brinkman-Forchheimer model along with the Maxwell equations is used. The nonlinear coupled equations using a finite volume approach (FVA) are solved numerically. The calculations are performed for different governing parameters such as Reynolds number, Nusselt number, Stuart number and Prandtl Number. The physical interpretation of velocity and isothermal contours is assigned through graphs. It is shown that the effects of a transverse magnetic field on flow behavior and heat transfer mechanism are more than that of the stream wise magnetic field. The configuration of streamlines and vorticity contours phenomena are also presented for porous diamond obstacle. Comparison of the numerical solutions with existing literature is also made.

  5. Advanced thermal energy storage concept definition study for solar Brayton power plants. Volume II. Thermal energy storage system sizing computer program. Period covered: July 1, 1976December 31, 1976

    Microsoft Academic Search

    Gintz

    1977-01-01

    This document describes the computer program used in conceptual studies of phase change and sensible heat thermal energy storage systems. The model assumes the phase change media is contained in a tube-in-bath configuration. The sensible heat medium is contained in high pressure tanks. The program has been used in conjunction with, but is not necessarily limited to, a high temperature,

  6. A review on phase change energy storage: materials and applications

    Microsoft Academic Search

    Mohammed M Farid; Amar M Khudhair; Siddique Ali K Razack; Said Al-Hallaj

    2004-01-01

    Latent heat storage is one of the most efficient ways of storing thermal energy. Unlike the sensible heat storage method, the latent heat storage method provides much higher storage density, with a smaller temperature difference between storing and releasing heat. This paper reviews previous work on latent heat storage and provides an insight to recent efforts to develop new classes

  7. Combined thermal storage pond and dry cooling tower waste heat rejection system for solar-thermal steam-electric power plants. Final report

    Microsoft Academic Search

    E. C. Guyer; J. G. Bourne; D. L. Brownell; R. M. Rose

    1979-01-01

    The thermal performance and economics of the combined thermal storage pond and dry cooling tower waste heat rejection system concept for solar-thermal steam-electric plants have been evaluated. Based on the computer simulation of the operation of southwest-sited solar-thermal plants, it has been determined that the combined pond-tower concept has significant cost and performance advantages over conventional dry cooling systems. Use

  8. Capric–myristic acid\\/expanded perlite composite as form-stable phase change material for latent heat thermal energy storage

    Microsoft Academic Search

    Ali Karaipekli; Ahmet Sar?

    2008-01-01

    The aim of this study is to prepare a novel form-stable phase change material (PCM) for latent heat thermal energy storage (LHTES) in buildings. A eutectic mixture of capric acid (CA) and myristic acid (MA) is incorporated with expanded perlite (EP). Thermal properties, thermal reliability, and thermal conductivity of the form-stable composite PCM are determined. The maximum CA–MA absorption of

  9. Analysis of Heat Charging and Discharging on the Phase Change Energy-Storage Composite Wallboard (PCECW) in Building

    E-print Network

    Yue, H.; Chen, C.; Liu, Y.; Guo, H.

    2006-01-01

    layers, use the intermediate differential format in space, and use the whole hidden differential format in the time (the retral Euler Format), in order to reach convergence. 4.2.2 Heat Balance Equation of the Room with the PCECW The transient... state heat transfer process satisfies three heat balance equations as follows: a) Heat balance equation of the outer surface of the wall: The heat conduction + the heat convection with the air + the solar radiation + the sky radiation + the earth...

  10. Rotation effects on coupled heat and mass transfer by unsteady MHD free convection flow in a porous medium past an infinite inclined plate

    NASA Astrophysics Data System (ADS)

    Ismail, Zulkhibri; Khan, Ilyas; Nasir, Nadirah Mohd.; Jusoh, Rahimah; Salleh, Mohd. Zuki; Shafie, Sharidan

    2014-07-01

    The effects of rotation on coupled heat and mass transfer by unsteady magnetohydrodynamic (MHD) free convection flow in a porous medium past an infinite inclined plate has been investigated. Exact solution using Laplace transforms technique has been obtained for the velocity, temperature and concentration fields. The analytical expressions for nondimensional skin-friction, Nusselt number and Sherwood number have been computed. The solutions of rotation parameters and inclination angle influences the flow fields have been discussed in detail. It is found that inclination angle tend to retard fluid flow in the primary and secondary flow directions, whereas rotation has a retarding influences on the primary flow direction but to accelerate in the secondary flow direction.

  11. Investigation of heat and mass transfer process in metal hydride hydrogen storage reactors, suitable for a solar powered water pump system

    NASA Astrophysics Data System (ADS)

    Coldea, I.; Popeneciu, G.; Lupu, D.; Misan, I.; Blanita, G.; Ardelean, O.

    2012-02-01

    The paper analyzes heat and mass transfer process in metal hydride hydrogen storage systems as key element in the development of a solar powered pump system. Hydrogen storage and compression performance of the developed reactors are investigated according to the type of metal alloys, the metal hydride bed parameters and system operating conditions. To reach the desired goal, some metal hydride from groups AB5 and AB2 were synthesized and characterized using elements substitution for tailoring their properties: reversible hydrogen absorption capacity between the hydrogen absorption and desorption pressures at equilibrium at small temperature differences. For the designed hydrogen storage reactors, a new technical solution which combines the effective increase of the thermal conductivity of MH bed and good permeability to hydrogen gas circulation, was implemented and tested. The results permitted us to develop a heat engine with metal hydride, the main element of the functional model of a heat operated metal hydride based water pumping system using solar energy. This is a free energy system able to deliver water, at a convenience flow and pressure, in remote places without conventional energy access.

  12. Experimental study of solid–liquid phase change in a spiral thermal energy storage unit

    Microsoft Academic Search

    J Banaszek; R Domañski; M Rebow; F El-Sagier

    1999-01-01

    A new idea on the use of a vertical spiral heat exchanger in a latent heat thermal energy storage system is analyzed experimentally. In this context, two important subjects are addressed. The first one is the temporal behavior of a phase change medium undergoing a non-isothermal solid–liquid phase change transition during its two-side heating or cooling by a working fluid

  13. Summary Report for Concentrating Solar Power Thermal Storage Workshop: New Concepts and Materials for Thermal Energy Storage and Heat-Transfer Fluids, May 20, 2011

    Microsoft Academic Search

    Glatzmaier

    2011-01-01

    This document summarizes a workshop on thermal energy storage for concentrating solar power (CSP) that was held in Golden, Colorado, on May 20, 2011. The event was hosted by the U.S. Department of Energy (DOE), the National Renewable Energy Laboratory, and Sandia National Laboratories. The objective was to engage the university and laboratory research communities to identify and define research

  14. Applications of thermal energy storage to process heat storage and recovery in the paper and pulp industry. Final report, September 1977May 1978

    Microsoft Academic Search

    J. H. Carr; P. J. Hurley; P. J. Martin

    1978-01-01

    Applications of Thermal Energy Storage (TES) in a paper and pulp mill power house were studied as one approach to the transfer of steam production from fossil fuel boilers to waste fuel (hog fuel) boilers. Data from specific mills were analyzed, and various TES concepts evaluated for application in the process steam supply system. Constant pressure and variable pressure steam

  15. Thermal storage for electric utilities

    NASA Technical Reports Server (NTRS)

    Swet, C. J.; Masica, W. J.

    1977-01-01

    Applications of the thermal energy storage (TES) principle (storage of sensible heat or latent heat, or heat storage in reversible chemical reactions) in power systems are evaluated. Load leveling behind the meter, load following at conventional thermal power plants, solar thermal power generation, and waste heat utilization are the principal TES applications considered. Specific TES examples discussed include: storage heaters for electric-resistance space heating, air conditioning TES in the form of chilled water or eutectic salt baths, hot water TES, and trans-seasonal storage in heated water in confined aquifers.

  16. Effect of prior growth temperature, type of enrichment medium, and temperature and time of storage on recovery of Listeria monocytogenes following high pressure processing of milk.

    PubMed

    Bull, Michelle K; Hayman, Melinda M; Stewart, Cynthia M; Szabo, Elizabeth A; Knabel, Stephen J

    2005-05-01

    A five-isolate cocktail of Listeria monocytogenes (10(3) cfu/ml in skim or whole raw milk) was subjected to 450 MPa for 900 s or 600 MPa for 90 s. The effects of prior growth temperature, type of milk (skim vs. whole), type of recovery-enrichment media (optimized Penn State University [oPSU] broth, Listeria Enrichment Broth [LEB], Buffered LEB [BLEB], Modified BLEB [MBLEB], and milk), storage temperature and storage time on the recovery of L. monocytogenes were examined. Optimized PSU broth significantly increased the recovery of L. monocytogenes following high pressure processing (HPP), and was 63 times more likely to recover L. monocytogenes following HPP, compared to LEB, BLEB and MBLEB broths (p<0.05; Odds Ratio=63.09, C.I. 23.70-167.96). There was a significant main effect for prior growth temperature (p<0.05). However, this relationship could not be interpreted given the significant interaction effects between temperature and both pressure and milk type. HPP-injured L. monocytogenes could be recovered using both LEB and oPSU broths after storage of milk at 4, 15 and 30 degrees C, with recovery being maximal after 24 to 72 h of storage; however, recovery yield dropped to 0% after prolonged storage of milk at 4 and 30 degrees C. In contrast, storage of milk at 15 degrees C yielded the most rapid rate of recovery and the highest recovery yield (100%), which remained high throughout the 14 days of storage at 15 degrees C. The above factors need to be taken into consideration when designing challenge studies to insure complete inactivation of L. monocytogenes and possibly other foodborne pathogens during high pressure processing of foods. PMID:15878406

  17. Large-scale jets from active galactic nuclei as a source of intracluster medium heating: cavities and shocks

    NASA Astrophysics Data System (ADS)

    Perucho, Manel; Martí, José-María; Quilis, Vicent; Ricciardelli, Elena

    2014-12-01

    The evolution of powerful extragalactic jets is not only interesting by itself, but also for its impact on the evolution of the host galaxy and its surroundings. We have performed long-term axisymmetric numerical simulations of relativistic jets with different powers to study their evolution through an environment with a pressure and density gradient. Our results show key differences in the evolution of jets with different powers in terms of the spatial and temporal scales of energy deposition. According to our results, the observed morphology in X-ray cavities requires that an important fraction of the jet's energetic budget is in the form of internal energy. Thus, light, lepton-dominated jets are favoured. In all cases, heating is mainly produced by shocks. Cavity overpressure is sustained by an important population of thermal particles. Our simulations reproduce the cool-core structure in projected, luminosity-weighted temperature. We have performed an additional simulation of a slow, massive jet and discuss the differences with its relativistic counterparts. Important qualitative and quantitative differences are found between the non-relativistic and the relativistic jets. Our conclusions point towards a dual mode of active galactic nuclei kinetic feedback, depending on the jet power.

  18. Solar thermal energy storage

    Microsoft Academic Search

    H. P. Garg; S. C. Mullick; A. K. Bhargava

    1985-01-01

    This book starts with a description of possible energy storage systems and the recent developments in the field. Then it moves on to the basics of sensible heat storage-discussing liquid, solid, and dual-media storage systems. Next, it deals with chemical energy storage, making use of detailed treatments of both thermal dissociation and catalytic reactions. It explores long-term energy storage concepts,

  19. Summary Report for Concentrating Solar Power Thermal Storage Workshop: New Concepts and Materials for Thermal Energy Storage and Heat-Transfer Fluids, May 20, 2011

    SciTech Connect

    Glatzmaier, G.

    2011-08-01

    This document summarizes a workshop on thermal energy storage for concentrating solar power (CSP) that was held in Golden, Colorado, on May 20, 2011. The event was hosted by the U.S. Department of Energy (DOE), the National Renewable Energy Laboratory, and Sandia National Laboratories. The objective was to engage the university and laboratory research communities to identify and define research directions for developing new high-temperature materials and systems that advance thermal energy storage for CSP technologies. This workshop was motivated, in part, by the DOE SunShot Initiative, which sets a very aggressive cost goal for CSP technologies -- a levelized cost of energy of 6 cents per kilowatt-hour by 2020 with no incentives or credits.

  20. Antimicrobial activity of plant compounds against Salmonella Typhimurium DT104 in ground pork and the influence of heat and storage on the antimicrobial activity.

    PubMed

    Chen, Cynthia H; Ravishankar, Sadhana; Marchello, John; Friedman, Mendel

    2013-07-01

    Salmonella enterica is a predominant foodborne pathogen that causes diarrheal illness worldwide. A potential method of inhibiting pathogenic bacterial growth in meat is through the introduction of plant-derived antimicrobials. The objectives of this study were to investigate the influence of heat (70°C for 5 min) and subsequent cold storage (4°C up to 7 days) on the effectiveness of oregano and cinnamon essential oils and powdered olive and apple extracts against Salmonella enterica serovar Typhimurium DT104 in ground pork and to evaluate the activity of the most effective antimicrobials (cinnamon oil and olive extract) at higher concentrations in heated ground pork. The surviving Salmonella populations in two groups (heated and unheated) of antimicrobial-treated pork were compared. Higher concentrations of the most effective compounds were then tested (cinnamon oil at 0.5 to 1.0% and olive extract at 3, 4, and 5%) against Salmonella Typhimurium in heated ground pork. Samples were stored at 4°C and taken on days 0, 3, 5, and 7 for enumeration of survivors. The heating process did not affect the activity of antimicrobials. Significant 1.3- and 3-log reductions were observed with 1.0% cinnamon oil and 5% olive extract, respectively, on day 7. The minimum concentration required to achieve . 1-log reduction in Salmonella population was 0.8% cinnamon oil or 4% olive extract. The results demonstrate the effectiveness of these antimicrobials against multidrug-resistant Salmonella Typhimurium in ground pork and their stability during heating and cold storage. The most active formulations have the potential to enhance the microbial safety of ground pork. PMID:23834804