WorldWideScience

Sample records for seasonal heat storage

  1. German central solar heating plants with seasonal heat storage

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, D.; Marx, R.; Nussbicker-Lux, J.; Ochs, F.; Heidemann, W. [Institute of Thermodynamics and Thermal Engineering (ITW), University of Stuttgart, Pfaffenwaldring 6, D-70550 Stuttgart (Germany); Mueller-Steinhagen, H. [Institute of Thermodynamics and Thermal Engineering (ITW), University of Stuttgart, Pfaffenwaldring 6, D-70550 Stuttgart (Germany); Institute of Technical Thermodynamics (ITT), German Aerospace Centre (DLR), Stuttgart (Germany)

    2010-04-15

    Central solar heating plants contribute to the reduction of CO{sub 2}-emissions and global warming. The combination of central solar heating plants with seasonal heat storage enables high solar fractions of 50% and more. Several pilot central solar heating plants with seasonal heat storage (CSHPSS) built in Germany since 1996 have proven the appropriate operation of these systems and confirmed the high solar fractions. Four different types of seasonal thermal energy stores have been developed, tested and monitored under realistic operation conditions: Hot-water thermal energy store (e.g. in Friedrichshafen), gravel-water thermal energy store (e.g. in Steinfurt-Borghorst), borehole thermal energy store (in Neckarsulm) and aquifer thermal energy store (in Rostock). In this paper, measured heat balances of several German CSHPSS are presented. The different types of thermal energy stores and the affiliated central solar heating plants and district heating systems are described. Their operational characteristics are compared using measured data gained from an extensive monitoring program. Thus long-term operational experiences such as the influence of net return temperatures are shown. (author)

  2. Compact seasonal PCM heat storage for solar heating systems

    DEFF Research Database (Denmark)

    Dannemand, Mark

    Space heating of buildings and preparation of domestic hot water accounts for a large part of the society’s energy consumption. Solar radiation is an abundant and renewable energy source which can be harvested by solar collectors and used to cover heating demands in the built environment....... The seasonal availability of solar energy does however not match with the heating demands in buildings which typically are large in winter periods when limited solar energy is available. Heat can be stored over a few days in water stores but continuous heat losses limits the storage periods. The possibility...... of storing heat from summer where solar energy is widely available to winter periods where the heating demands are large, allows for implementing more renewable energy in our energy system. The phase change material (PCM) sodium acetate trihydrate (SAT) melts at 58 °C. The melting process requires...

  3. Central solar heating plants with seasonal storage

    Energy Technology Data Exchange (ETDEWEB)

    Chuard, D; Hadorn, J C; Van Gilst, J; Aranovitch, E; Hardacre, A G; Ofverholm, E [eds.

    1982-09-14

    On May 9, 1979, the Federal Department for Buildings released instructions concerning the use of alternative energies. The federal energy policy is to be as much as possible independent on oil imports. The canton Fribourg decided to equip the new maintenance and service center for the national high-road N12, with alternative energy, resources, and to apply new concepts with respect to passive and active solar energy. The project uses active solar energy with an earth-storage and heat pump. A conventional oil-heating system provides energy for peak-loads and can be operated in stand-by. A delay in the construction of the earth storage sub system was requested because it was intended to optimize the system with respect to the solar sub system, and heat pump sub system. The design work was done by SORANE which also is the coordinator for Switzerland in the I.E.A. Task VII. However, the preplanning of the project started in 1978 before the I.E.A. Task VII started. As a consequence, many design parameters were determined before 1980. The optimization of the solar collector, heat-pump etc. sub system was performed by a simulation approach developed by SORANE. The Vaulruz service center has been commissioned during the winter 1981/82.

  4. Thermal behavior of a heat exchanger module for seasonal heat storage

    DEFF Research Database (Denmark)

    Fan, Jianhua; Furbo, Simon; Andersen, Elsa

    2012-01-01

    Experimental and theoretic investigations are carried out to study the heat transfer capacity rate of a heat exchanger module for seasonal heat storage with sodium acetate trihydrate (SAT) supercooling in a stable way. A sandwich heat storage test module has been built with the phase change...... material (PCM) storage box in between two plate heat exchangers. Charge of the PCM storage is investigated experimentally with solid phase SAT as initial condition. Discharge of the PCM storage with the presence of crystallization is studied experimentally. Fluid flow and heat transfer in the PCM module......, recommendations on how best to transfer heat to and from the seasonal heat storage module are given....

  5. Development of seasonal heat storage based on stable supercooling of a sodium acetate water mixture

    DEFF Research Database (Denmark)

    Furbo, Simon; Fan, Jianhua; Andersen, Elsa

    2012-01-01

    A number of heat storage modules for seasonal heat storages based on stable supercooling of a sodium acetate water mixture have been tested by means of experiments in a heat storage test facility. The modules had different volumes and designs. Further, different methods were used to transfer heat...... to and from the sodium acetate water mixture in the modules. By means of the experiments: • The heat exchange capacity rates to and from the sodium acetate water mixture in the heat storage modules were determined for different volume flow rates. • The heat content of the heat storage modules were determined....... • The reliability of the supercooling was elucidated for the heat storage modules for different operation conditions. • The reliability of a cooling method used to start solidification of the supercooled sodium acetate water mixture was elucidated. The method is making use of boiling CO2 in a small tank in good...

  6. Experimental and theoretic investigations of thermal behavior of a seasonal water pit heat storage

    DEFF Research Database (Denmark)

    Fan, Jianhua; Huang, Junpeng; Chatzidiakos, Angelos

    Seasonal heat storages are considered essential for district heating systems because they offer flexibility for the system to integrate different fluctuating renewable energy sources. Water pit thermal storages (PTES) have been successfully implemented in solar district heating plants in Denmark....... Thermal behavior of a 75,000 m3 water pit heat storage in Marstal solar heating plant was investigated experimentally and numerically. Temperatures at different levels of the water pit storage and temperatures at different depths of the ground around the storage were monitored and analyzed. A simulation...... model of the water pit storage is built to investigate development of temperatures in and around the storage. The calculated temperatures are compared to the monitored temperatures with an aim to validate the simulation model. Thermal stratification in the water pit heat storage and its interaction...

  7. Economic analyses of central solar heating systems with seasonal storage

    Energy Technology Data Exchange (ETDEWEB)

    Lund, P D; Keinonen, R.S.

    1986-10-01

    Economic optimization of large active community solar heating systems with annual thermal storage is discussed. The economic evaluation is based on a thermal performance simulation model employing one hour time steps and on detailed up-date data. Different system configurations and sub-system sizes have been considered. For Northern European weather conditions (60/sup 0/N) and with at least 400-500 residential units, the life-cycle cost of delivered solar heat was 6.5-7.5 c/kWh for 50% fraction of non-purchased energy. For a solar fraction of 70%, the solar energy price would be 8 c/kWh.

  8. Energy density and storage capacity cost comparison of conceptual solid and liquid sorption seasonal heat storage systems for low-temperature space heating

    NARCIS (Netherlands)

    Scapino, L.; Zondag, H.A.; Van Bael, J.; Diriken, J.; Rindt, C.C.M.

    Sorption heat storage can potentially store thermal energy for long time periods with a higher energy density compared to conventional storage technologies. A performance comparison in terms of energy density and storage capacity costs of different sorption system concepts used for seasonal heat

  9. Reactive force field development for magnesium chloride hydrates and its application for seasonal heat storage

    NARCIS (Netherlands)

    Pathak, A.D.; Gaastra-Nedea, S.V.; Duin, van A.C.T.; Zondag, H.A.; Rindt, C.C.M.; Smeulders, D.M.J.

    2016-01-01

    MgCl2 hydrates are considered as high-potential candidates for seasonal heat storage materials. These materials have high storage capacity and fast dehydration kinetics. However, as a side reaction to dehydration, hydrolysis may occur. Hydrolysis is an irreversible reaction, which produces HCl gas

  10. Experimental and in silico characterization of xylitol as seasonal heat storage material

    NARCIS (Netherlands)

    Zhang, H.; Duquesne, M.; Godin, A.; Niedermaier, S.; Palomo del Barrio, E.; Gaastra - Nedea, S.V.; Rindt, C.C.M.

    Solid-liquid phase change is one of the most favorable means of compact heat storage in the built environment. Recent studies propose C4-C6 polyalcohols for seasonal storage applications, for their high latent melting enthalpy, evident supercooling effect, and low environmental impact. In this

  11. Experimental studies on seasonal heat storage based on stable supercooling of a sodium acetate water mixture

    DEFF Research Database (Denmark)

    Furbo, Simon; Dragsted, Janne; Fan, Jianhua

    2011-01-01

    to transfer heat to and from the module have been tested. Further, a solidification start method, based on a strong cooling of a small part of the salt water mixture in the module by boiling CO2 in a small brass tank in good thermal contact to the outer side of the module wall, has been tested. Tests......Laboratory tests of a 230 l seasonal heat storage module with a sodium acetate water mixture have been carried out. The aim of the tests is to elucidate how best to design a seasonal heat storage based on the salt water mixture, which supercools in a stable way. The module can be a part...... of a seasonal heat storage, that will be suitable for solar heating systems which can fully cover the yearly heat demand of Danish low energy buildings. The tested module has approximately the dimensions 2020 mm x 1285 mm x 80 mm. The module material is steel and the wall thickness is 2 mm. Different methods...

  12. Material Research on Salt Hydrates for Seasonal Heat Storage Application in a Residential Environment

    Energy Technology Data Exchange (ETDEWEB)

    Ferchaud, C.J.; Zondag, H.A.; De Boer, R. [ECN Biomass and Energy Efficiency, Petten (Netherlands)

    2013-09-15

    Water vapor sorption in salt hydrates is a promising method to realize seasonal solar heat storage in the residential sector. Several materials already showed promising performance for this application. However, the stability of these materials needs to be improved for long-term (30 year) application in seasonal solar heat storages. The purpose of this article is to identify the influence of the material properties of the salt hydrates on the performance and the reaction kinetics of the sorption process. The experimental investigation presented in this article shows that the two salt hydrates Li2SO4.H2O and CuSO4.5H2O can store and release heat under the operating conditions of a seasonal solar heat storage in a fully reversible way. However, these two materials show differences in terms of energy density and reaction kinetics. Li2SO4.H2O can release heat with an energy density of around 0.80 GJ/m{sup 3} within 4 hours of rehydration at 25C, while CuSO4.5H2O needs around 130 hours at the same temperature to be fully rehydrated and reaches an energy density of 1.85 GJ/m{sup 3}. Since the two salts are dehydrated and hydrated under the same conditions, this difference in behavior is directly related to the intrinsic properties of the materials.

  13. Operation Performance of Central Solar Heating System with Seasonal Storage Water Tank in Harbin

    Institute of Scientific and Technical Information of China (English)

    YE Ling; JIANG Yi-qiang; YAO Yang; ZHANG Shi-cong

    2009-01-01

    This paper presented a preliminary research on the central solar heating system with seasonal stor-age(CSHSSS)used in cold climate in China.A mathematical model of the solar energy seasonal storage water tank used in the central solar heating system was firstly developed based on energy conservation.This was fol-lowed by the simulation of the CSHSSS used in a two-floor villa in Harbin,and analysis of the impacts on storage water temperature of tank volume,solar collector area,tank burial depth,insulation thickness around the tank,etc.The results show there is a relatively economical tank volume to optimize the system efficiency,which de-creases with increasing tank volume at the constant collector area,and increases with increasing collector area at the constant tank volume.Furthermore,the insulation thickness has obvious effect on avoiding heat loss,while the tank burial depth doesn't.In addition-the relationship between the solar collector efficiency and storage wa-ter temperature is also obtained,it decreases quickly with increasing storing water temperature,and then in-creases slowly after starting space heating system.These may be helpful for relevant design and optimization in cold climates in China and all over the world.

  14. Performance Evaluation of a Demonstration System with PCM for Seasonal Heat Storage: Charge with Evacuated Tubular Collectors

    DEFF Research Database (Denmark)

    Englmair, Gerald; Furbo, Simon; Kong, Weiqiang

    with sunshine, the storage system performance was evaluated regarding charge with solar heat. It shows the system behavior during typical operation resulting from the control strategy. Heat transfer rates from the solar collector array (22.4 m2 aperture area) to the heat stores reached a peak of 19 kW, when PCM......A seasonal heat storage with phase change material (PCM) for a solar space heating and domestic hot water combisystem was tested in automated operation during charge with solar collectors. A water tank was operating as buffer heat storage. Based on measurements during a representative day...... temperatures were increasing with the state of charge. This is in contrast to maximization of solar yield. However, the energy conversion efficiency (65 %) of the collector array was satisfying. By considering pump electricity consumption, an overall performance ratio of 30.8 was obtained....

  15. Solar district heating and seasonal heat storage - state of the art; Solare Nahwaerme und Saisonale Waermespeicherung - Stand der Technik

    Energy Technology Data Exchange (ETDEWEB)

    Pfeil, M.; Hahne, E. [Zentrum fuer Sonnenenergie- und Wasserstoff-Forschung Baden-Wuerttemberg (ZSW), Stuttgart (Germany). Geschaeftsbereich Solarthermische Energietechnik; Lottner, V. [BEO Biologie, Energie Oekologie, Juelich (Germany); Schulz, M. [Stuttgart Univ. (Germany). Inst. fuer Thermodynamik und Waermetechnik

    1998-02-01

    Solar energy technology becomes more and more important for space and water heating of residential buildings. Compared to small systems for single-family houses, the specific investment cost of big solar plants is lower and a higher contribution of solar energy can be achieved. In central solar heating plants with seasonal storage (CSHPSS), more than 50% of the total heat demand of residential areas can be covered by solar energy. The first pilot plants for CSHPSS are operating in Germany since 1996. The first results of the accompanying monitoring program show good agreement between calculated and actual solar contribution. (orig.) [Deutsch] Die Nutzung solarer Niedertemperaturwaerme zur Brauchwassererwaermung und zur Beheizung von Wohngebaeuden erfaehrt in Deutschland ein immer groesseres Interesse. Solare Grossanlagen haben gegenueber solaren Kleinanlagen den Vorteil, dass mit geringeren Investitions- und Waermekosten groessere Anlagenertraege erzielt werden koennen. In Verbindung mit saisonaler Waermespeicherung erreichen solare Grossanlagen Deckungsanteile von 50% und darueber am Gesamtwaermebedarf von Wohnsiedlungen. Die ersten Pilotanlagen zur solaren Nahwaerme mit saisonalem Waermespeicher gingen 1996 in Betrieb und werden derzeit detailliert vermessen. Erste Ergebnisse zeigen, dass die vorausberechneten Werte fuer den Jahresenergieertrag erreicht werden koennen. (orig.)

  16. Performance Analysis and Application of Three Different Computational Methods for Solar Heating System with Seasonal Water Tank Heat Storage

    Directory of Open Access Journals (Sweden)

    Dongliang Sun

    2013-01-01

    Full Text Available We analyze and compare three different computational methods for a solar heating system with seasonal water tank heat storage (SHS-SWTHS. These methods are accurate numerical method, temperature stratification method, and uniform temperature method. The accurate numerical method can accurately predict the performance of the system, but it takes about 4 to 5 weeks, which is too long and hard for the performance analysis of this system. The temperature stratification method obtains relatively accurate computation results and takes a relatively short computation time, which is about 2 to 3 hours. Therefore, this method is most suitable for the performance analysis of this system. The deviation of the computational results of the uniform temperature method is great, and the time consumed is similar to that of the temperature stratification method. Therefore, this method is not recommended herein. Based on the above analyses, the temperature stratification method is applied to analyze the influence of the embedded depth of water tank, the thickness of thermal insulation material, and the collection area on the performance of this system. The results will provide a design basis for the related demonstration projects.

  17. Application of large underground seasonal thermal energy storage in district heating system : a model-based energy performance assessment of a pilot system in Chifeng, China

    NARCIS (Netherlands)

    Xu, L.; Torrens Galdiz, J.I.; Guo, F.; Yang, X.; Hensen, J.L.M.

    Seasonal thermal energy storage (STES) technology is a proven solution to resolve the seasonal discrepancy between heating energy generation from renewables and building heating demands. This research focuses on the performance assessment of district heating (DH) systems powered by low-grade energy

  18. Characterization of sugar alcohols as seasonal heat storage media - experimental and theoretical investigations

    NARCIS (Netherlands)

    Zhang, H.; van Wissen, R.M.J.; Nedea, S.V.; Rindt, C.C.M.

    2014-01-01

    Sugar alcohols are under investigation as phase change materials for long term heat storage applications. The thermal performance in such systems is strongly dominated by the nucleation and crystal growth kinetics, which is further linked to the crystal-melt interfacial free energy (surface

  19. Core Flooding Experiments and Reactive Transport Modeling of Seasonal Heat Storage in the Hot Deep Gassum Sandstone Formation

    DEFF Research Database (Denmark)

    Holmslykke, Hanne D.; Kjøller, Claus; Fabricius, Ida Lykke

    2017-01-01

    Seasonal storage of excess heat in hot deep aquifers is considered to optimize the usage of commonly available energy sources. The chemical effects of heating the Gassum Sandstone Formation to up to 150 degrees C is investigated by combining laboratory core flooding experiments with petrographic...... analysis and geochemical modeling. Synthetic formation water is injected into two sets of Gassum Formation samples at 25, 50 (reservoir temperature), 100, and 150 degrees C with a velocity of 0.05 and 0.1 PV/h, respectively. Results show a significant increase in the aqueous concentration of silicium...

  20. Numerical simulation of seasonal heat storage in a contaminated shallow aquifer - Temperature influence on flow, transport and reaction processes

    Science.gov (United States)

    Popp, Steffi; Beyer, Christof; Dahmke, Andreas; Bauer, Sebastian

    2015-04-01

    The energy market in Germany currently faces a rapid transition from nuclear power and fossil fuels towards an increased production of energy from renewable resources like wind or solar power. In this context, seasonal heat storage in the shallow subsurface is becoming more and more important, particularly in urban regions with high population densities and thus high energy and heat demand. Besides the effects of increased or decreased groundwater and sediment temperatures on local and large-scale groundwater flow, transport, geochemistry and microbiology, an influence on subsurface contaminations, which may be present in the urban surbsurface, can be expected. Currently, concerns about negative impacts of temperature changes on groundwater quality are the main barrier for the approval of heat storage at or close to contaminated sites. The possible impacts of heat storage on subsurface contamination, however, have not been investigated in detail yet. Therefore, this work investigates the effects of a shallow seasonal heat storage on subsurface groundwater flow, transport and reaction processes in the presence of an organic contamination using numerical scenario simulations. A shallow groundwater aquifer is assumed, which consists of Pleistoscene sandy sediments typical for Northern Germany. The seasonal heat storage in these scenarios is performed through arrays of borehole heat exchangers (BHE), where different setups with 6 and 72 BHE, and temperatures during storage between 2°C and 70°C are analyzed. The developing heat plume in the aquifer interacts with a residual phase of a trichloroethene (TCE) contamination. The plume of dissolved TCE emitted from this source zone is degraded by reductive dechlorination through microbes present in the aquifer, which degrade TCE under anaerobic redox conditions to the degradation products dichloroethene, vinyl chloride and ethene. The temperature dependence of the microbial degradation activity of each degradation step is

  1. Experimental study of a solar-assisted ground-coupled heat pump system with solar seasonal thermal storage in severe cold areas

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiao; Zheng, Maoyu; Zhang, Wenyong; Zhang, Shu; Yang, Tao [School of Municipal and Environmental Engineering, Harbin Institute of Technology, NO 202 Haihe Road, Harbin, Hei Longjiang 150090 (China)

    2010-11-15

    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 a priority, and the building was heated by a ground-coupled heat pump (GCHP) and solar collectors alternately. The results show that the system can meet the heating-cooling energy needs of the building. In the heating mode, the heat directly supplied by solar collectors accounted for 49.7% of the total heating output, and the average coefficient of performance (COP) of the heat pump and the system were 4.29 and 6.55, respectively. In the cooling mode, the COP of the system reached 21.35, as the heat pump was not necessary to be started. After a year of operation, the heat extracted from the soil by the heat pump accounted for 75.5% of the heat stored by solar seasonal thermal storage. The excess heat raised the soil temperature to a higher level, which was favorable for increasing the COP of the heat pump. (author)

  2. Development of Seasonal Storage in Denmark

    DEFF Research Database (Denmark)

    Heller, Alfred

    2000-01-01

    National survey on seasonal (thermal, large-scale) storage activities in Denmark. A storage programme under the Danish Energy Agency. Programme background, objectives, activities, projects and results.Technologies presented: Pit water storage, gravel water storage with pipe heat exchangers, lining...... materials for pit and lid designs....

  3. Ground water heat pumps and cooling with ground water basins as seasonal storage; Grundvandsvarmepumper og -koeling med grundvandsmagasiner som saesonlager

    Energy Technology Data Exchange (ETDEWEB)

    2008-04-15

    Ground water temperature is constant all the year round, in Denmark approximately 9 deg. C, which is ideal for a number of cooling purposes including cooling of buildings. The structures in which the ground water flows (sand, gravel and chalk) are efficient for storing coldness and heat over longer periods. By using seasonal storage of low-temperature heat and coldness in ground water layers close to the terrain it is feasible to reach profitable energy savings of up to 90% for cooling and heating of e.g. hotels, airports, shopping malls, office buildings and other larger buildings. At the same time the large energy savings means major reduction of CO{sub 2} emissions. (BA)

  4. Underground seasonal storage of industrial waste heat; Saisonale Speicherung industrieller Abwaerme im Untergrund

    Energy Technology Data Exchange (ETDEWEB)

    Reuss, M.; Mueller, J. [Bayerische Landesanstalt fuer Landtechnik, TU Muenchen-Weihenstephan, Freising (Germany)

    1998-12-31

    The thermal efficiency of subject systems, especially at higher temperatures is influenced by heat and humidity transport underground. Thermal conductivity and specific thermal capacity depend on the humidity content of the soil. A simulation model was developed that describes the coupled heat and humidity transport in the temperature range up to 90 C. This model will be validated in laboratory and field tests and then be used for designing and analysing underground stores. Pilot plants for the storage of industrial waste heat were designed and planned on the basis of this simulation. In both cases these are cogeneration plants whose waste heat was to be used for space heating and as process energy. Both plants have a very high demand of electric energy which is mostly supplied by the cogeneration plant. The waste heat is put into the store during the summer. In the winter heat is supplied by both the store and the cogeneration plant. In both cases the store has a volume of approx. 15,000 cubic metres with 140 and 210 pits located in a depth of 30 and 40 metres. The plants are used to carry out extensive measurements for the validation of simulation models. (orig.) [Deutsch] Die thermische Leistungsfaehigkeit solcher Systeme wird insbesondere im hoeheren Temperaturbereich durch den Waerme- und Feuchtetransport im Untergrund beeinflusst. Sowohl die Waermeleitfaehigkeit als auch die spezifische Waermekapazitaet sind vom Feuchtegehalt des Bodens abhaengig. Es wurde ein Simulationsmodell entwickelt, das den gekoppelten Waerme- und Feuchtetransport im Temperaturbereich bis 90 C beschreibt. Dieses Modell wird an Labor- und Feldexperimenten validiert und dient dann zur Auslegung und Analyse von Erdwaermesonden-Speichern. Basierend auf diesen theoretischen Grundlagenarbeiten wurden Pilotanlagen zur saisonalen Speicherung industrieller Abwaerme ausgelegt und geplant. In beiden Faellen handelt es sich um Kraft/Waermekopplungsanlagen, deren Abwaerme zur Gebaeudeheizung und

  5. Core Flooding Experiments and Reactive Transport Modeling of Seasonal Heat Storage in the Hot Deep Gassum Sandstone Formation

    DEFF Research Database (Denmark)

    Holmslykke, Hanne D.; Kjøller, Claus; Fabricius, Ida Lykke

    2017-01-01

    Seasonal storage of excess heat in hot deep aquifers is considered to optimize the usage of commonly available energy sources. The chemical effects of heating the Gassum Sandstone Formation to up to 150 degrees C is investigated by combining laboratory core flooding experiments with petrographic ...... minor effects on the properties of the reservoir and that storage of excess heat in the Gassum Formation in the Stenlille area may be possible provided operational precautions are taken....... analysis and geochemical modeling. Synthetic formation water is injected into two sets of Gassum Formation samples at 25, 50 (reservoir temperature), 100, and 150 degrees C with a velocity of 0.05 and 0.1 PV/h, respectively. Results show a significant increase in the aqueous concentration of silicium...... and iron with increasing temperature due to dissolution of silica and siderite. Increasing the reservoir temperature from 50 to 100 degrees C enhanced the naturally occurring weathering of Na-rich feldspar to kaolinite. Dissolution of quartz increased sharply above 100 degrees C and was the dominating...

  6. Heat pipe heat storage performance

    Energy Technology Data Exchange (ETDEWEB)

    Caruso, A; Pasquetti, R [Univ. de Provence, Marseille (FR). Inst. Universitaire des Systemes; Grakovich, L P; Vasiliev, L L [A.V. Luikov Heat and Mass Transfer Inst. of the BSSR, Academy of Sciences, Minsk (BY)

    1989-01-01

    Heat storage offers essential thermal energy saving for heating. A ground heat store equipped with heat pipes connecting it with a heat source and to the user is considered in this paper. It has been shown that such a heat exchanging system along with a batch energy source meets, to a considerable extent, house heating requirements. (author).

  7. Status seminar `98: Solar-supported district heating with seasonal heat storage. Status report `98; Status-Seminar `98: Solarunterstuetzte Nahwaermeversorgung - Saisonale Waermespeicherung. Statusbericht `98

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-12-31

    This status report refers to the BMBF (Federal Ministry for Education, Science, Research and Technology) status seminar: Solar-assisted district heat supply - seasonal heat storage that took place in Neckarsulm on 19th and 20th May. 1998. The report contains the reference papers and the status reports of all projects supported under the Ministry`s SOLARTHERMIE programme that have already been finished or are still running. (orig.) [Deutsch] Der vorliegende Statusbericht wird anlaesslich des BMBF-Statusseminars: Solarunterstuetzte Nahwaermeversorgung - Saisonale Waermespeicherung am 19. und 20. Mai 1998 in Neckarsulm herausgegeben. Der Bericht enthaelt neben den Tagungsbeitraegen auch die Sachstandsberichte aller Projekte, die zu diesem Thema in den letzten Jahren von BMBF in dem Programm SOLARTHERMIE-2000 bereits abgeschlossen wurden oder z.Zt. gefoerdert werden. (orig.)

  8. Large solar heating system with seasonal storage for buld drying in Lisse, the Netherlands

    NARCIS (Netherlands)

    Bokhoven, T.P.; Geus, A.C. de

    1996-01-01

    Within IEA Task 14 (Advanced Solar Systems) of the IEA Solar Heating and Cooling Programme a working group was established dealing with large advanced solar energy systems (the Large Systems Working group). The goal of this working group was to generate a common base of experiences for the design

  9. A modular approach to inverse modelling of a district heating facility with seasonal thermal energy storage

    DEFF Research Database (Denmark)

    Tordrup, Karl Woldum; Poulsen, Uffe Vestergaard; Nielsen, Carsten

    2017-01-01

    We use a modular approach to develop a TRNSYS model for a district heating facility by applying inverse modelling to one year of operational data for individual components. We assemble the components into a single TRNSYS model for the full system using the accumulation tanks as a central hub conn...

  10. Coupling Geothermal Heat Pumps with Underground Seasonal Thermal Energy Storage (EW-201135)

    Science.gov (United States)

    2017-03-01

    with the addition of the adiabatic pads, a water supply connection and a drainage system . During the baseline data-logging period at MCLB-B3700, an... system . Rainwater and near surface water will always contain some oxygen due to the presence of atmospheric oxygen. Deep (100+ ft. deep) groundwater...loop Heat Exchangers (GHX) with closed loop systems or via direct ground water use with open-loop systems , which conventional GHP systems in the U.S

  11. Coupling Geothermal Heat Pumps (GHP) With Underground Seasonal Thermal Energy Storage (USTES)

    Science.gov (United States)

    2017-03-21

    subsurface geology as a thermal battery, as opposed to a radiator . BTES is a design solution in areas where there are not aquifers suitable for ATES...Wells are defined by DC Law § 8-103.01(26A) as any test hole, shaft, or soil excavation created by any means including, but not limited to, drilling...Resources An annual sampling requirement for non-residential systems. Driller or installer is required to hold a "heat pump installation" permit through

  12. Solar heating system with seasonal storage for the 'Heumatt' housing development in Zurich; Solare Waermeversorgung mit saisonalem Speicher fuer die Wohnsiedlung Heumatt, Zuerich Seebach

    Energy Technology Data Exchange (ETDEWEB)

    Hartmann, P.; Juzi, H.

    2003-07-01

    This final report for the Swiss Federal Office of Energy describes a project proposal for the seasonal storage of heat produced by solar collectors to provide a fifty-percent coverage of the space heating and hot water demands of a housing scheme with 140 dwellings in Zurich, Switzerland. The report describes the project, including the collection of solar energy and the storage of heat in an underground storage area. Figures are given on the estimates of energy requirements and energy production. The investments needed for the realisation of the project are quoted. The report also includes a detailed report on the concept and reviews of the project made by the University of Applied Technology in Winterthur and that of Southern Switzerland.

  13. Heat transport and storage

    International Nuclear Information System (INIS)

    Despois, J.

    1977-01-01

    Recalling the close connections existing between heat transport and storage, some general considerations on the problem of heat distribution and transport are presented 'in order to set out the problem' of storage in concrete form. This problem is considered in its overall plane, then studied under the angle of the different technical choices it involves. The two alternatives currently in consideration are described i.e.: storage in a mined cavity and underground storage as captive sheet [fr

  14. Development of a seasonal thermochemical storage system

    NARCIS (Netherlands)

    Cuypers, R.; Maraz, N.; Eversdijk, J.; Finck, C.J.; Henquet, E.M.P.; Oversloot, H.P.; Spijker, J.C. van 't; Geus, A.C. de

    2012-01-01

    In our laboratories, a seasonal thermochemical storage system for dwellings and offices is being designed and developed. Based on a thermochemical sorption reaction, space heating, cooling and generation of domestic hot water will be achieved with up to 100% renewable energy, by using solar energy

  15. Seasonal Solar Thermal Absorption Energy Storage Development.

    Science.gov (United States)

    Daguenet-Frick, Xavier; Gantenbein, Paul; Rommel, Mathias; Fumey, Benjamin; Weber, Robert; Gooneseker, Kanishka; Williamson, Tommy

    2015-01-01

    This article describes a thermochemical seasonal storage with emphasis on the development of a reaction zone for an absorption/desorption unit. The heat and mass exchanges are modelled and the design of a suitable reaction zone is explained. A tube bundle concept is retained for the heat and mass exchangers and the units are manufactured and commissioned. Furthermore, experimental results of both absorption and desorption processes are presented and the exchanged power is compared to the results of the simulations.

  16. Thermochemical seasonal solar heat storage in salt hydrates for residential applications - Influence of the water vapor pressure on the desorption kinetics of MgSO4.7H2O

    NARCIS (Netherlands)

    Ferchaud, C.; Scherpenborg, R.A.A.; Zondag, H.A.; Boer, de R.

    2013-01-01

    An interesting thermochemical material for compact seasonal heat storage is magnesium sulfate heptahydrate MgSO4.7H2O. Previous studies in the field showed that this material presents a storage energy density of 1 GJ/m3 when the material is built in a TC storage system with a 50% porosity packed bed

  17. Thermal contact resistance in carbon nanotube enhanced heat storage materials

    NARCIS (Netherlands)

    Zhang, H.; Nedea, S.V.; Rindt, C.C.M.; Smeulders, D.M.J.

    2015-01-01

    Solid-liquid phase change is one of the most favorable means of compact and economical heat storage in the built environment. In such storage systems, the vast available solar heat is stored as latent heat in the storage materials. Recent studies suggest using sugar alcohols as seasonal heat storage

  18. Application of Solar Seasonal Heat Storage System Research%太阳能季节性蓄热系统的应用研究

    Institute of Scientific and Technical Information of China (English)

    韩宇

    2014-01-01

    Farmers in cold areas, single-family villa construction, explore the solar cross seasonal thermal storage technology, the application of the heating in winter. Design scheme from solar radiation, this paper analyzes the solar energy can provide heat in summer and winter building heat consumption. Solar energy storage, directly within the heating scheme is put forward, considering the factors, saves the initial investment in order to reduce the cost, heating scheme of solar energy in combination with water source heat pump system was put forward, combined with air can heat pump and solar energy heating scheme. Considering the energy saving efficiency and the factors that influence the operation cost of the study of using solar composite heat pump heating has a certain guiding significance.%针对严寒地区农户、别墅独栋建筑,探索太阳能跨季节储热技术,在冬季供暖中的应用。设计方案从太阳能的年辐射量入手,分析了太阳能夏季可以提供的热量、以及建筑物冬季消耗的热量。提出太阳能存储、直接内供暖的方案,考虑到节省初投资的因素,为了减少造价,提出了太阳能结合水源热泵系统的供暖方案,以及太阳能结合空气能热泵的供暖方案。考虑了节能效率与运行费用的影响因素,该研究对采用太阳能复合热泵采暖具有一定的指导意义。

  19. Prototype thermochemical heat storage with open reactor system

    NARCIS (Netherlands)

    Zondag, H.A.; Kikkert, B.; Smeding, S.F.; Boer, de R.; Bakker, M.

    2013-01-01

    Thermochemical (TC) heat storage is an interesting technology for future seasonal storage of solar heat in the built environment. This technology enables high thermal energy storage densities and low energy storage losses. A small-scale laboratory prototype TC storage system has been realized at

  20. Cooperative heat transfer and ground coupled storage system

    Science.gov (United States)

    Metz, P.D.

    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.

  1. Solar Energy: Heat Storage.

    Science.gov (United States)

    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…

  2. A central solar-industrial waste heat heating system with large scale borehole thermal storage

    NARCIS (Netherlands)

    Guo, F.; Yang, X.; Xu, L.; Torrens, I.; Hensen, J.L.M.

    2017-01-01

    In this paper, a new research of seasonal thermal storage is introduced. This study aims to maximize the utilization of renewable energy source and industrial waste heat (IWH) for urban district heating systems in both heating and non-heating seasons through the use of large-scale seasonal thermal

  3. Underground storage of heat

    International Nuclear Information System (INIS)

    Despois, J.; Nougarede, F.

    1976-01-01

    The interest laying in heat storage is envisaged taking account of the new energy context, with a view to optimizing the use of production means of heat sources hardly modulated according to the demand. In such a way, a natural medium, without any constructions cost but only an access cost is to be used. So, porous and permeable rocky strata allowing the use of a pressurized water flow as a transfer fluid are well convenient. With such a choice high temperatures (200 deg C) may be obtained, that are suitable for long transmissions. A mathematical model intended for solving the conservation equations in the case of heat storage inside a confined water layer is discussed. An approach of the operating conditions of storage may involve either a line-up arrangement (with the hot drilling at the center, the cold drillings being aligned on both sides) or a radial arrangement (with cold drillings at the peripheral edge encircling the hot drilling at the center of the layer). The three principal problems encountered are: starting drilling, and the circuit insulation and control [fr

  4. Improving Geothermal Heat Pump Air Conditioning Efficiency with Wintertime Cooling using Seasonal Thermal Energy Storage (STES). Application Manual

    Science.gov (United States)

    2016-11-01

    loop) is used to remove heat from the hot vapor, causing it to condense back into a liquid. The liquid is then routed back to the evaporator to complete...reversed, and heat is extracted from the heat source (the ground loop) to evaporate the liquid refrigerant. The refrigerant vapor condenses in a...towers are typically operated during hot summer months and rely mainly on water evaporation for cooling. Dry fluid coolers cool using heat transfer

  5. R&D of Thermochemical reactor concepts to enable seasonal heat storage of solar energy in residential houses

    NARCIS (Netherlands)

    Zondag, H.A.; Bakker, M.; Schuitema, R.; Bleijendaal, L.P.J.; Cot Gores, J.; Essen, van V.M.; Helden, van W.G.J.

    2009-01-01

    About 30% of the energy consumption in the Netherlands is taken up by residences and offices. Most of this energy is used for heating purposes. In order to reduce the consumption of fossil fuels, it is necessary to reduce this energy use as much as possible by means of insulation and heat recovery.

  6. Solar heat storages in district heating networks

    Energy Technology Data Exchange (ETDEWEB)

    Ellehauge, K. (Ellehauge og Kildemoes, AArhus (DK)); Engberg Pedersen, T. (COWI A/S, Kgs. Lyngby (DK))

    2007-07-15

    This report gives information on the work carried out and the results obtained in Denmark on storages for large solar heating plants in district heating networks. Especially in Denmark the share of district heating has increased to a large percentage. In 1981 around 33% of all dwellings in DK were connected to a district heating network, while the percentage in 2006 was about 60% (in total 1.5 mio. dwellings). In the report storage types for short term storage and long term storages are described. Short term storages are done as steel tanks and is well established technology widely used in district heating networks. Long term storages are experimental and used in connection with solar heating. A number of solar heating plants have been established with either short term or long term storages showing economy competitive with normal energy sources. Since, in the majority of the Danish district heating networks the heat is produced in co-generation plants, i.e. plants producing both electricity and heat for the network, special attention has been put on the use of solar energy in combination with co-generation. Part of this report describes that in the liberalized electricity market central solar heating plants can also be advantageous in combination with co-generation plants. (au)

  7. Hot tap water production by a 4 kW sorption segmented reactor in household scale for seasonal heat storage

    NARCIS (Netherlands)

    Gaeini, M.; van Alebeek, R.; Scapino, L.; Zondag, H. A.; Rindt, C C.M.

    2018-01-01

    Replacing fossil fuel by solar energy as a promising sustainable energy source, is of high interest, for both electricity and heat generation. However, to reach high solar thermal fractions and to overcome the mismatch between supply and demand of solar heat, long term heat storage is necessary. A

  8. End-of-season heating fuel report

    International Nuclear Information System (INIS)

    1992-01-01

    The year-end report notes that the 1991-92 heating season had lower average oil prices (retail home heating fuel) than the past two winters and prices remained relatively stable throughout the season. This year, the heating season average was $.87 per gallon, $1.05 for kerosene, and $1.33 for propane

  9. Cost of heat from a seasonal source

    Science.gov (United States)

    Reilly, R. W.; Brown, D. R.; Huber, H. D.

    Results are reported of an investigation to estimate the cost of aquifer thermal energy storage (ATES) from a seasonal heat source. The cost of supplying energy (hot water) from an ATES system is estimated. Three types of loads are investigated: point demands, residential developments, and a multidistrict city. Several technical and economic factors are found to control the economic performance of an ATES system. Costs are found to be prohibitive for systems of small size, long transmission distances, and employing expensive purchased thermal energy. ATES is found to be cost-competitive with oil-fired and electric hot water delivery systems under a broad range of potential situations.

  10. Study of the reversible water vapour sorption process of MgSO4.7H2O and MgCl2.6H2O under the conditions of seasonal solar heat storage

    NARCIS (Netherlands)

    Ferchaud, C.; Zondag, H.A.; Veldhuis, J.B.J.; Boer, de R.

    2012-01-01

    The characterization of the structural, compositional and thermodynamic properties of MgSO4.7H2O and MgCl2.6H2O has been done using in-situ X-ray Diffraction and thermal analyses (TG/DSC) under practical conditions for seasonal heat storage (Tmax=150°C, p(H2O)=13 mbar). This study showed that these

  11. Annual cycle solar energy utilization with seasonal storage. Part 7. Examination on design and control of the system partially recovering exhaust heat of heat pump; Kisetsukan chikunetsu ni yoru nenkan cycle taiyo energy riyo system ni kansuru kenkyu. 7. Bubuntekina hainetsu kaishu wo koryoshita baai no sekkei seigyoho no kento

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, H; Okumiya, M [Nagoya University, Nagoya (Japan)

    1996-10-27

    The capacity and performance of the existing system that recovers the overall heating and cooling exhaust heat completely into a seasonal storage tank and the system that discharges the exhaust heat slightly to the outside and recovers it partially were compared and investigated. The system uses a central single-duct discharge system as an air-conditioning system. A heat pump and a flat-plate solar collector installed on the roof of a building are used as the heat source. The seasonal storage tank in the ground just under the building is a cylindrical water tank of 5 m deep with the concrete used as body. The upper surface of a storage tank is heat-insulated by a stylo-platform of 200 mm, and the lower side surface by a stylo-platform of 100 mm. Calculation when the difference in temperature used in a seasonal storage tank is set to 35{degree}C and 25{degree}C was performed for the system that has two control methods. The overall exhaust heat recovery system is almost the same in energy performance as the partial exhaust heat recovery system. The partial exhaust heat recovery system is more advantageous on the economic side. 4 refs., 6 figs., 3 tabs.

  12. Solarthermie 2000 - Partial programme 3: Solar district heat - solar campus Juelich, feasibility study of the seasonal heat storage; Solarthermie 2000, Teilprogramm 3: Solare Nahwaerme - Solar-Campus Juelich, Machbarkeitsuntersuchung des saisonalen Waermespeichers

    Energy Technology Data Exchange (ETDEWEB)

    Braxein, A. [Iwu - Ingenieurgesellschaft fuer Wasser und Umwelt mbH, Aachen (Germany); Spaete, F.; Repschlaeger, H. [Solar-Inst. Juelich (Germany); Friedel, J. [Stadtwerke Juelich (Germany)

    1998-12-31

    The heart of the solar-assisted district heating system for the solar campus Juelich is going to be a seasonal underground store with a capacity of 2,500 cubic metres, e.g. a rather small long-term storage. The aim of the project was to prove the technical and financial feasibility of the underground store by developing a building concept for the storage and to determine whether this concept was also suitable for larger storage facilities. The design of the floating lid and the suitability of various building materials were studied by means of a physical model. The resulting storage concept shows an underground storage pit whose shape is an inverted square pyramid base with a seal of double-layer PP-foil and a thermal insulation of pressure-resistant mineral wool in the upper part. The lid consists of 16 square walk-on floating containers with an edge length of 6.50 metres and a height of 1.0 metre each. Tests and calculations showed that the concept can be realised. The building costs for the small storage with a capacity of 2,500 cubic metres will amount to approx. DM 370 per cubic metre, costs for larger volumes of 25,000 cubic metres will amount to approx. DM 150 DM per cubic metre of water stored. (orig.) [Deutsch] Das Kernstueck der solargestuetzten Nahwaermeversorgung fuer den Solar-Campus Juelich soll ein 2500 m{sup 3} grosser, saisonaler Erdbeckenspeicher bilden, also ein relativ kleiner Langzeitspeicher. Ziel des Vorhabens war, die technische und finanzielle Machbarkeit des geplanten Erdbeckenspeichers durch ein baureifes Speicherkonzept nachzuweisen sowie die Uebertragbarkeit auf grosse saisonale Speicher gleicher Bauart zu untersuchen. Die konstruktive Ausbildung der schwimmenden Deckelkonstruktion sowie die Eignung verschiedener Baumaterialien wurden mit Hilfe eines physikalischen Modells untersucht. Das resultierende Speicherkonzept sieht einen Erdbeckenspeicher in Form eines umgedrehten, quadratischen Pyramidenstumpfes mit einer Abdichtung aus

  13. Seasonal energy storage - PV-hydrogen systems

    Energy Technology Data Exchange (ETDEWEB)

    Leppaenen, J. [Neste Oy/NAPS (Finland)

    1998-10-01

    PV systems are widely used in remote areas e.g. in telecommunication systems. Typically lead acid batteries are used as energy storage. In northern locations seasonal storage is needed, which however is too expensive and difficult to realise with batteries. Therefore, a PV- battery system with a diesel backup is sometimes used. The disadvantages of this kind of system for very remote applications are the need of maintenance and the need to supply the fuel. To overcome these problems, it has been suggested to use hydrogen technologies to make a closed loop autonomous energy storage system

  14. Studies on heat storage, 9

    International Nuclear Information System (INIS)

    Taoda, Hiroshi; Hayakawa, Kiyoshi; Kawase, Kaoru; Kosaka, Mineo

    1985-01-01

    To estimate the extent of thermal oxidative aging of the crosslinked and surface coated polyethylene pellets used as a latent heat thermal storage material, their deterioration was investigated by applying the heating-cooling cycle which simulated the daily insolation over 6 months (8-hour holding at 150 deg C as the highest temperature in a day followed by 5-hour holding at 30 deg C as the lowest one). The degradation, e.g., the lowering of heat of crystallization and in crystallization temperature, is thought to be caused by both the decrease in molecular weight of polyethylene due to thermal oxidative decomposition and the crosslinking between produced radicals. With the increase in the degree of crosslinking and branching in a molecular chain which has low bond dissociation energy, thermal deterioration of polyethylene proceeds more rapidly. Polyethylene pellets can endure long periods of practical heat cycling as a thermal storage material when they are treated with radical scavengers under proper control of their crosslinking degrees. The repeating heat storage experiments by using the developed polyethylene thermal storage material were performed and very promising results were obtained. (author)

  15. Aquifer Thermal Energy Storage for Seasonal Thermal Energy Balance

    Science.gov (United States)

    Rostampour, Vahab; Bloemendal, Martin; Keviczky, Tamas

    2017-04-01

    Aquifer Thermal Energy Storage (ATES) systems allow storing large quantities of thermal energy in subsurface aquifers enabling significant energy savings and greenhouse gas reductions. This is achieved by injection and extraction of water into and from saturated underground aquifers, simultaneously. An ATES system consists of two wells and operates in a seasonal mode. One well is used for the storage of cold water, the other one for the storage of heat. In warm seasons, cold water is extracted from the cold well to provide cooling to a building. The temperature of the extracted cold water increases as it passes through the building climate control systems and then gets simultaneously, injected back into the warm well. This procedure is reversed during cold seasons where the flow direction is reversed such that the warmer water is extracted from the warm well to provide heating to a building. From the perspective of building climate comfort systems, an ATES system is considered as a seasonal storage system that can be a heat source or sink, or as a storage for thermal energy. This leads to an interesting and challenging optimal control problem of the building climate comfort system that can be used to develop a seasonal-based energy management strategy. In [1] we develop a control-oriented model to predict thermal energy balance in a building climate control system integrated with ATES. Such a model however cannot cope with off-nominal but realistic situations such as when the wells are completely depleted, or the start-up phase of newly installed wells, etc., leading to direct usage of aquifer ambient temperature. Building upon our previous work in [1], we here extend the mathematical model for ATES system to handle the above mentioned more realistic situations. Using our improved models, one can more precisely predict system behavior and apply optimal control strategies to manage the building climate comfort along with energy savings and greenhouse gas reductions

  16. Solar Heating System with Building-Integrated Heat Storage

    DEFF Research Database (Denmark)

    Heller, Alfred

    1996-01-01

    Traditional solar heating systems cover between 5 and 10% of the heat demand fordomestic hot water and comfort heating. By applying storage capacity this share can beincreased much. The Danish producer of solar heating systems, Aidt-Miljø, markets such a system including storage of dry sand heated...... by PP-pipe heat exchanger. Heat demand is reduced due to direct solar heating, and due to storage. Heat demand is reduced due to direct solar heating, due to storage and due to lower heat losses through the ground. In theory, by running the system flow backwards through the sand storage, active heating...... can be achieved.The objective of the report is to present results from measured system evaluation andcalculations and to give guidelines for the design of such solar heating systems with building integrated sand storage. The report is aimed to non-technicians. In another report R-006 the main results...

  17. Latent Heat Storage Through Phase Change Materials

    Indian Academy of Sciences (India)

    IAS Admin

    reducing storage volume for different materials. The examples are numerous: ... Latent heat is an attractive way to store solar heat as it provides high energy storage density, .... Maintenance of the PCM treated fabric is easy. The melted PCM.

  18. EPR ohmic heating energy storage

    International Nuclear Information System (INIS)

    Heck, F.M.; Stillwagon, R.E.; King, E.I.

    1977-01-01

    The Ohmic Heating (OH) Systems for all the Experimental Power Reactor (EPR) designs to date have all used temporary energy storage to assist in providing the OH current charge required to build up the plasma current. The energies involved (0.8 x 10 9 J to 1.9 x 10 9 J) are so large as to make capacitor storage impractical. Two alternative approaches are homopolar dc generators and ac generators. Either of these can be designed for pulse duty and can be made to function in a manner similar to a capacitor in the OH circuit and are therefore potential temporary energy storage devices for OH systems for large tokamaks. This study compared total OH system costs using homopolar and ac generators to determine their relative merits. The total system costs were not significantly different for either type of machine. The added flexibility and the lower maintenance of the ac machine system make it the more attractive approach

  19. The European Market for Seasonal Gas Storage

    International Nuclear Information System (INIS)

    Mahan, A.

    2006-02-01

    European demand for gas will grow in the years to come. Simultaneously, gas production in Europe will decrease and imported gas will be needed to replace indigenous production. Gas demand is not constant during the year. There are variations in demand on different timescales ranging from seasonal to hourly. Variations in demand are characterised by two main parameters: working volume and deliverability. Working volume - the amount of gas that can be supplied above the baseload production volume during a long (cold) period- is primarily needed to cope with the summer-winter pattern of gas consumption. Most of the summer-winter pattern comes from the temperature sensitive gas consumption by households and service industries. Gas usage by industry and the power sector are more evenly spread throughout the year and need less working volume. Deliverability - the amount of gas per hour that can be generated on a (very) cold day above the baseload capacity - is the ability to produce large volumes during short periods, e.g. for extremely cold days, or during peak periods during a day. In this paper we argue that a large amount of additional working volume will be required over the coming years. First, flexible European production will be replaced by long-distance import gas, and second, the gas market is expected to grow further. Todays market appears focus mainly on cavems for storage volume. Cavems have little working volume but are ideal for trading purposes. Consequently, Europe may be facing a deficit in working volume, i.e. the ability to cope with seasonal changes in demand. This paper aims to widen the discussion of this matter and give rise to this concern by setting out a broad analysis, exploring the market drivers for seasonal storage and identifying the public interest issues for this market. Chapter 2 gives an overview of demand for and supply characteristics of gas flexibility. Chapter 3 describes the role of gas storage facilities in the gas market

  20. Heat storage in alloy transformations

    Science.gov (United States)

    Birchenall, C. E.

    1980-01-01

    Heats of transformation of eutectic alloys were measured for many binary and ternary systems by differential scanning calorimetry and thermal analysis. Only the relatively cheap and plentiful elements Mg, Al, Si, P, Ca, Cu, Zn were considered. A method for measuring volume change during transformation was developed using x-ray absorption in a confined sample. Thermal expansion coefficients of both solid and liquid states of aluminum and of its eutectics with copper and with silicon also were determined. Preliminary evaluation of containment materials lead to the selection of silicon carbide as the initial material for study. Possible applications of alloy PCMs for heat storage in conventional and solar central power stations, small solar receivers and industrial furnace operations are under consideration.

  1. Model-based energy performance assessment of the world largest underground seasonal thermal energy storage in a pilot district heating system in Chifeng City

    NARCIS (Netherlands)

    Xu, L.; Torrens Galdiz, J.I.; Guo, F.; Yang, X.; Hensen, J.L.M.

    2017-01-01

    District heating systems play an important role in supporting energy transition by using and storing energy delivered by renewable and other low-grade energy sources such as industrial waste heat. However, this low-grade heat is not always able to satisfy the heating demand, including space heating

  2. Energy storage

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This chapter discusses the role that energy storage may have on the energy future of the US. The topics discussed in the chapter include historical aspects of energy storage, thermal energy storage including sensible heat storage, latent heat storage, thermochemical heat storage, and seasonal heat storage, electricity storage including batteries, pumped hydroelectric storage, compressed air energy storage, and superconducting magnetic energy storage, and production and combustion of hydrogen as an energy storage option

  3. Effect of kinetics on the thermal performance of a sorption heat storage reactor

    NARCIS (Netherlands)

    Gaeini, M.; Zondag, H.A.; Rindt, C.C.M.

    2016-01-01

    To reach high solar fractions for solar thermal energy in the built environment, long-term heat storage is required to overcome the seasonal mismatch. A promising method for long term heat storage is to use thermochemical materials, TCMs. In this research, a lab-scale test thermochemical heat

  4. Optimal design and application of a compound cold storage system combining seasonal ice storage and chilled water storage

    NARCIS (Netherlands)

    Yan, C.; Shi, W.; Li, X.; Zhao, Y.

    2016-01-01

    Seasonal cold storage using natural cold sources for cooling is a sustainable cooling technique. However, this technique suffers from limitations such as large storage space and poor reliability. Combining seasonal storage with short-term storage might be a promising solution while it is not

  5. Primary energy savings using heat storage for biomass heating systems

    Directory of Open Access Journals (Sweden)

    Mitrović Dejan M.

    2012-01-01

    Full Text Available District heating is an efficient way to provide heat to residential, tertiary and industrial users. The heat storage unit is an insulated water tank that absorbs surplus heat from the boiler. The stored heat in the heat storage unit makes it possible to heat even when the boiler is not working, thus increasing the heating efficiency. In order to save primary energy (fuel, the boiler operates on nominal load every time it is in operation (for the purpose of this research. The aim of this paper is to analyze the water temperature variation in the heat storage, depending on the heat load and the heat storage volume. Heat load is calculated for three reference days, with average daily temperatures from -5 to 5°C. The primary energy savings are also calculated for those days in the case of using heat storage in district heating.[Projekat Ministarstva nauke Republike Srbije, br. TR 33051: The concept of sustainable energy supply of settlements with energy efficient buildings

  6. Research programme 'Active Solar Energy Use - Solar Heating and Heat Storage'. Activities and projects 2003

    International Nuclear Information System (INIS)

    Hadorn, J.-C.; Renaud, P.

    2003-01-01

    In this report by the research, development and demonstration (RD+D) programme coordinators the objectives, activities and main results in the area of solar heating and heat storage in Switzerland are presented for 2003. In a stagnating market environment the strategy of the Swiss Federal Office of Energy mainly consists in improving the quality and durability of solar collectors and materials, optimizing combisystems for space heating and domestic hot water preparation, searching for storage systems with a higher energy storage density than in the case of sensible heat storage in water, developing coloured solar collectors for more architectonic freedom, and finalizing a seasonal heat storage project for 100 dwellings to demonstrate the feasibility of solar fractions larger than 50% in apartment houses. Support was granted to the Swiss Testing Facility SPF in Rapperswil as in previous years; SPF was the first European testing institute to perform solar collector labeling according to the new rules of the 'Solar Keymark', introduced in cooperation with the European Committee for Standardization CEN. Several 2003 projects were conducted within the framework of the Solar Heating and Cooling Programme of the International Energy Agency IEA. Computerized simulation tools were improved. With the aim of jointly producing high-temperature heat and electric power a solar installation including a concentrating collector and a thermodynamic machine based on a Rankine cycle is still being developed. Seasonal underground heat storage was studied in detail by means of a validated computer simulation programme. Design guidelines were obtained for such a storage used in the summer time for cooling and in the winter time for space heating via a heat pump: depending on the ratio 'summer cooling / winter heating', cooling requires a cooling machine, or direct cooling without such a machine is possible. The report ends up with the list of all supported RD+D projects

  7. Laboratory Testing of Solar Combi System with Compact Long Term PCM Heat Storage

    DEFF Research Database (Denmark)

    Johansen, Jakob Berg; Englmair, Gerald; Dannemand, Mark

    2016-01-01

    To enable the transition from fossil fuels as a primary heat source for domestic hot water preparation and space heating solar thermal energy has great potential. The heat from the sun has the disadvantage that it is not always available when there is a demand. To solve this mismatch a thermal...... seasonal storage can be used to store excess heat from the summer to the winter when the demand is higher than the supply. Installing a long term thermal storage in a one family house it needs to be compact and sensible heat storages are not suitable. A latent heat storage with a phase change material (PCM...

  8. A DFT-based comparative equilibrium study of thermal dehydration and hydrolysis of CaCl2 hydrates and MgCl2 hydrates for seasonal heat storage

    NARCIS (Netherlands)

    Pathak, A.D.; Gaastra-Nedea, S.V.; Zondag, H.A.; Rindt, C.C.M.; Smeulders, D.M.J.

    2016-01-01

    Salt hydrates store solar energy in chemical form via a reversible dehydration–hydration reaction. However, as a side reaction to dehydration, hydrolysis (HCl formation) may occur in chloride based salt hydrates (specially in MgCl2 hydrates), affecting the durability of the storage system. The

  9. First-principles study of chemical mixtures of CaCl2 and MgCl2 hydrates for optimized seasonal heat storage

    NARCIS (Netherlands)

    Pathak, A. D.; Tranca, I.; Nedea, S. V.; Zondag, H. A.; Rindt, C. C.M.; Smeulders, D. M.J.

    2017-01-01

    Chloride-based salt hydrates form a promising class of thermochemical materials (TCMs), having high storage capacity and fast kinetics. In the charging cycles of these hydrates however hydrolysis might appear along with dehydration. The HCl produced during the hydrolysis degrades and corrodes the

  10. Study of the reversible water vapour sorption process of MgSO{sub 4}.7H{sub 2}O and MgCl{sub 2}.6H{sub 2}O under the conditions of seasonal solar heat storage

    Energy Technology Data Exchange (ETDEWEB)

    Ferchaud, C.J.; De Boer, R. [Eindhoven University of Technology, Department of Mechanical Engineering, Eindhoven (Netherlands); Zondag, H.A.; Veldhuis, J.B.J. [ECN Biomass and Energy Efficiency, Petten (Netherlands)

    2012-08-15

    The characterization of the structural, compositional and thermodynamic properties of MgSO{sub 4}.7H{sub 2}O and MgCl{sub 2}.6H{sub O} has been done for seasonal heat storage using in-situ X-ray Diffraction and thermal analyses (TG/DSC) under practical conditions for seasonal heat storage (T{sub max} = 150C, p(H{sub 2}O)=13 mbar). This study showed that these two materials release heat after a dehydration/hydration cycle with energy densities of 0.38 GJ/m{sup 3} for MgSO{sub 4}.7H{sub 2}O and 0.71 GJ/m{sup 3} MgCl{sub 2}.6H{sub 2}O. The low heat release found for MgSO{sub 4}.7H2O is mainly attributed to the amorphization of the material during the dehydration performed at 13 mbar which reduces its sorption capacity during the rehydration. MgCl{sub 2}.6H{sub 2}O presents a high energy density which makes this material interesting for the seasonal heat storage in domestic applications. This material would be able to fulfil the winter heat demand of a passive house estimated at 6 GJ with a packed bed reactor of 8.5 m{sup 3}. However, a seasonal heat storage system based on the water vapour sorption process in MgCl{sub 2}.6H{sub 2}O should be carefully set with a restricted temperature of 40C for the hydration reaction to avoid the liquefaction of the material at ambient temperature which limits its performances for long term storage.

  11. Unregulated heat output of a storage heater

    OpenAIRE

    Lysak, Oleg Віталійович

    2017-01-01

    In the article the factors determining the heat transfer between the outer surfaces of a storage heater and the ambient air. This heat exchange is unregulated, and its definition is a precondition for assessing heat output range of this type of units. It was made the analysis of the literature on choosing insulating materials for each of the external surfaces of storage heaters: in foreign literature, there are recommendations on the use of various types of insulation depending on the type of...

  12. Heat storage in the Andaman Sea

    Digital Repository Service at National Institute of Oceanography (India)

    RameshBabu, V.; Sastry, J.S.

    Heat storage in the Andaman Sea in upper 20 m, where a strong halocline seems to inhibit vertical heat transport has been evaluated and discussed in relation to the other parameters of heat budget. Estimation of annual evaporation gives rise to 137...

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  14. Medium Deep High Temperature Heat Storage

    Science.gov (United States)

    Bär, Kristian; Rühaak, Wolfram; Schulte, Daniel; Welsch, Bastian; Chauhan, Swarup; Homuth, Sebastian; Sass, Ingo

    2015-04-01

    Heating of buildings requires more than 25 % of the total end energy consumption in Germany. Shallow geothermal systems for indirect use as well as shallow geothermal heat storage systems like aquifer thermal energy storage (ATES) or borehole thermal energy storage (BTES) typically provide low exergy heat. The temperature levels and ranges typically require a coupling with heat pumps. By storing hot water from solar panels or thermal power stations with temperatures of up to 110 °C a medium deep high temperature heat storage (MDHTS) can be operated on relatively high temperature levels of more than 45 °C. Storage depths of 500 m to 1,500 m below surface avoid conflicts with groundwater use for drinking water or other purposes. Permeability is typically also decreasing with greater depth; especially in the crystalline basement therefore conduction becomes the dominant heat transport process. Solar-thermal charging of a MDHTS is a very beneficial option for supplying heat in urban and rural systems. Feasibility and design criteria of different system configurations (depth, distance and number of BHE) are discussed. One system is designed to store and supply heat (300 kW) for an office building. The required boreholes are located in granodioritic bedrock. Resulting from this setup several challenges have to be addressed. The drilling and completion has to be planned carefully under consideration of the geological and tectonical situation at the specific site.

  15. District heating and heat storage using the solution heat of an ammonia/water system

    International Nuclear Information System (INIS)

    Taube, M.; Peier, W.; Mayor, J.C.

    1976-01-01

    The article describes a model for the optimum use of the heat energy generated in a nuclear power station for district heating and heat storage taking account of the electricity and heat demand varying with time. (HR/AK) [de

  16. Investigation of Heat Pump Operation Strategies with Thermal Storage in Heating Conditions

    Directory of Open Access Journals (Sweden)

    Wangsik Jung

    2017-12-01

    Full Text Available A heat pump with thermal storage system is a system that operates a heat pump during nighttime using inexpensive electricity; during this time, the generated thermal energy is stored in a thermal storage tank. The stored thermal energy is used by the heat pump during daytime. Based on a model of a dual latent thermal storage tank and a heat pump, this study conducts control simulations using both conventional and advanced methods for heating in a building. Conventional methods include the thermal storage priority method and the heat pump priority method, while advanced approaches include the region control method and the dynamic programming method. The heating load required for an office building is identified using TRNSYS (Transient system simulation, used for simulations of various control methods. The thermal storage priority method shows a low coefficient of performance (COP, while the heat pump priority method leads to high electricity costs due to the low use of thermal storage. In contrast, electricity costs are lower for the region control method, which operates using the optimal part load ratio of the heat pump, and for dynamic programming, which operates the system by following the minimum cost path. According to simulation results for the winter season, the electricity costs using the dynamic programming method are 17% and 9% lower than those of the heat pump priority and thermal storage priority methods, respectively. The region control method shows results similar to the dynamic programming method with respect to electricity costs. In conclusion, advanced control methods are proven to have advantages over conventional methods in terms of power consumption and electricity costs.

  17. The energy challenge of a post-fossil world: Seasonal energy storage

    International Nuclear Information System (INIS)

    Forsberg, C.

    2009-01-01

    Fossil fuels are an energy source and an energy storage system. The demand for electricity and heat varies daily, weekly, and seasonally with seasonal variations often varying by a factor of two or more. The variable demand is met by fossil fuels because 1) fossil fuels are inexpensive to store in coal piles, oil tanks, and underground natural gas storage facilities and 2) the capital cost of the equipment to burn fossil fuels and convert the energy to heat or electricity is small relative to the cost of the fossil fuels. Concerns about climate change may limit the conventional use of fossil fuels. The alternative low-carbon energy production systems (nuclear, fossil fuels with carbon dioxide sequestration, wind, and solar) are capital-intensive energy sources with low operating costs. To obtain favorable economics these technologies must operate at full capacity; but, their output does not match energy demand. We have energy alternatives to fossil fuels but no replacements for the energy storage capabilities or fossil fuels. Proposed strategies and technologies to address the grand storage challenge (including seasonal storage of electricity) are described. The options suggest a nuclear-renewable future to address seasonal energy storage needs in a low-carbon world.

  18. Performance analysis of an integrated energy storage and energy upgrade thermochemical solid–gas sorption system for seasonal storage of solar thermal energy

    International Nuclear Information System (INIS)

    Li, Tingxian; Wang, Ruzhu; Kiplagat, Jeremiah K.; Kang, YongTae

    2013-01-01

    An innovative dual-mode thermochemical sorption energy storage method is proposed for seasonal storage of solar thermal energy with little heat losses. During the charging phase in summer, solar thermal energy is stored in form of chemical bonds resulting from thermochemical decomposition process, which enables the stored energy to be kept several months at ambient temperature. During the discharging phase in winter, the stored thermal energy is released in the form of chemical reaction heat resulting from thermochemical synthesis process. Thermodynamic analysis showed that the advanced dual-mode thermochemical sorption energy storage is an effective method for the long-term seasonal storage of solar energy. A coefficient of performance (COP h ) of 0.6 and energy density higher than 1000 kJ/kg of salt can be attained from the proposed system. During the discharging phase at low ambient temperatures, the stored thermal energy can be upgraded by use of a solid–gas thermochemical sorption heat transformer cycle. The proposed thermochemical sorption energy storage has distinct advantages over the conventional sensible heat and latent heat storage, such as higher energy storage density, little heat losses, integrated energy storage and energy upgrade, and thus it can contribute to improve the seasonal utilization of solar thermal energy. - Highlights: ► A dual-mode solid thermochemical sorption is proposed for seasonal solar thermal energy storage. ► Energy upgrade techniques into the energy storage system are integrated. ► Performance of the proposed seasonal energy storage system is evaluated. ► Energy density and COP h from the proposed system are as high as 1043 kJ/kg of salt and 0.60, respectively

  19. OPTIMUM HEAT STORAGE DESIGN FOR SDHW SYSTEMS

    DEFF Research Database (Denmark)

    Shah, Louise Jivan; Furbo, Simon

    1997-01-01

    Two simulation models have been used to analyse the heat storage design’s influence on the thermal performance of solar domestic hot water (SDHW) systems. One model is especially designed for traditional SDHW systems based on a heat storage design where the solar heat exchanger is a built-in spiral....... The other model is especially designed for low flow SDHW systems based on a mantle tank.The tank design’s influence on the thermal performance of the SDHW systems has been investigated in a way where only one tank parameter has been changed at a time in the calculations. In this way a direct analysis...

  20. Optimum heat storage design for SDHWsystems

    DEFF Research Database (Denmark)

    Shah, Louise Jivan; Furbo, Simon

    1997-01-01

    -in spiral. The other model is especially designed for low flow SDHWsystems based on a mantle tank.The tank design's influence on the thermal performance of the SDHWsystems has been investigated in a way where only one tank parameter has been changed at a time in the calculations. In this way a direct......Two simulation models have been used to analyse the heat storage design's influence on the thermal performance of solar domestic hot water systems, SDHWsystems. One model is especially designed for traditional SDHWsystems based on a heat storage design where the solar heat exchanger is a built...

  1. Energetic and Exergy Efficiency of a Heat Storage Unit for Building Heating

    International Nuclear Information System (INIS)

    Hazami, Mejdi; Kooli, Sami; Lazaar, Meriem; Farhat, Abdelhamid; Belghith, Ali

    2009-01-01

    This paper deals with a numerical and experimental investigation of a daily solar storage system conceived and built in Laboratoire de Maitrise des Technologies de l Energie (LMTE, Borj Cedria). This system consists mainly of the storage unit connected to a solar collector unit. The storage unit consists of a wooden case with dimension of 5 m 3 (5 m x 1m x 1m) filed with fin sand. Inside the wooden case was buried a network of a polypropylene capillary heat exchanger with an aperture area equal to 5 m 2 . The heat collection unit consisted of 5 m 2 of south-facing solar collector mounted at a 37 degree tilt angle. In order to evaluate the system efficiency during the charging period (during the day) and discharging period (during the night) an energy and exergy analyses were applied. Outdoor experiments were also carried out under varied environmental conditions for several consecutive days. Results showed that during the charging period, the average daily rates of thermal energy and exergy stored in the heat storage unit were 400 and 2.6 W, respectively. It was found that the net energy and exergy efficiencies in the charging period were 32 pour cent and 22 pour cent, respectively. During the discharging period, the average daily rates of the thermal energy and exergy recovered from the heat storage unit were 2 kW and 2.5 kW, respectively. The recovered heat from the heat storage unit was used for the air-heating of a tested room (4 m x 3 m x 3 m). The results showed that 30 pour cent of the total heating requirement of the tested room was obtained from the heat storage system during the whole night in cold seasons

  2. Cyclic high temperature heat storage using borehole heat exchangers

    Science.gov (United States)

    Boockmeyer, Anke; Delfs, Jens-Olaf; Bauer, Sebastian

    2016-04-01

    The transition of the German energy supply towards mainly renewable energy sources like wind or solar power, termed "Energiewende", makes energy storage a requirement in order to compensate their fluctuating production and to ensure a reliable energy and power supply. One option is to store heat in the subsurface using borehole heat exchangers (BHEs). Efficiency of thermal storage is increasing with increasing temperatures, as heat at high temperatures is more easily injected and extracted than at temperatures at ambient levels. This work aims at quantifying achievable storage capacities, storage cycle times, injection and extraction rates as well as thermal and hydraulic effects induced in the subsurface for a BHE storage site in the shallow subsurface. To achieve these aims, simulation of these highly dynamic storage sites is performed. A detailed, high-resolution numerical simulation model was developed, that accounts for all BHE components in geometrical detail and incorporates the governing processes. This model was verified using high quality experimental data and is shown to achieve accurate simulation results with excellent fit to the available experimental data, but also leads to large computational times due to the large numerical meshes required for discretizing the highly transient effects. An approximate numerical model for each type of BHE (single U, double U and coaxial) that reduces the number of elements and the simulation time significantly was therefore developed for use in larger scale simulations. The approximate numerical model still includes all BHE components and represents the temporal and spatial temperature distribution with a deviation of less than 2% from the fully discretized model. Simulation times are reduced by a factor of ~10 for single U-tube BHEs, ~20 for double U-tube BHEs and ~150 for coaxial BHEs. This model is then used to investigate achievable storage capacity, injection and extraction rates as well as induced effects for

  3. Thermal performance and heat transport in aquifer thermal energy storage

    Science.gov (United States)

    Sommer, W. T.; Doornenbal, P. J.; Drijver, B. C.; van Gaans, P. F. M.; Leusbrock, I.; Grotenhuis, J. T. C.; Rijnaarts, H. H. M.

    2014-01-01

    Aquifer thermal energy storage (ATES) is used for seasonal storage of large quantities of thermal energy. Due to the increasing demand for sustainable energy, the number of ATES systems has increased rapidly, which has raised questions on the effect of ATES systems on their surroundings as well as their thermal performance. Furthermore, the increasing density of systems generates concern regarding thermal interference between the wells of one system and between neighboring systems. An assessment is made of (1) the thermal storage performance, and (2) the heat transport around the wells of an existing ATES system in the Netherlands. Reconstruction of flow rates and injection and extraction temperatures from hourly logs of operational data from 2005 to 2012 show that the average thermal recovery is 82 % for cold storage and 68 % for heat storage. Subsurface heat transport is monitored using distributed temperature sensing. Although the measurements reveal unequal distribution of flow rate over different parts of the well screen and preferential flow due to aquifer heterogeneity, sufficient well spacing has avoided thermal interference. However, oversizing of well spacing may limit the number of systems that can be realized in an area and lower the potential of ATES.

  4. Optimum heat storage design for heat integrated multipurpose batch plants

    CSIR Research Space (South Africa)

    Stamp, J

    2011-01-01

    Full Text Available procedure is presented tha journal homepage: www All rights reserved. ajozi T, Optimum heat storage grated multipurpose batch plants , South Africa y usage in multipurpose batch plants has been in published literature most present methods, time... � 2pL?u?kins ? 1 h3A3?u?cu?U (36) The internal area for heat loss by convection from the heat transfer medium is given by Constraint (37) and the area for convective heat transfer losses to the environment is given in Constraint (38). A1?u? ? 2...

  5. Aquifer thermal energy (heat and chill) storage

    Energy Technology Data Exchange (ETDEWEB)

    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.

  6. Seven Operation Modes and Simulation Models of Solar Heating System with PCM Storage Tank

    Directory of Open Access Journals (Sweden)

    Juan Zhao

    2017-12-01

    Full Text Available A physical model and dynamic simulation models of a solar phase-change heat storage heating system with a plate solar collector, phase-change material (PCM storage tank, plate heat exchanger, and auxiliary heat sources were established. A control strategy and numerical models for each of seven different operation modes that cover the entire heating season of the system were developed for the first time. The seven proposed operation modes are Mode 1: free cooling; Mode 2: reservation of heat absorbed by the solar collector in the PCM storage tank when there is no heating demand; Mode 3: direct supply of the heating demand by the solar collector; Mode 4: use of the heat absorbed by the solar collector to meet the heating demands, with the excess heat stored in the PCM storage tank; Mode 5: use of heat stored in the PCM storage tank to meet the heating demands, Mode 6: combined use of heat stored in the PCM storage tank and the auxiliary heating sources to meet the heating demands; and Mode 7: exclusive use of the auxiliary heat sources in order to meet the heating demands. Mathematical models were established for each of the above seven operation modes, taking into consideration the effects of the outdoor meteorological parameters and terminal load on the heating system. The real-time parameters for the entire heating season of the system with respect to the different operation modes can be obtained by solving the simulation models, and used as reference for the optimal design and operation of the actual system.

  7. Thermochemical heat storage for high temperature applications. A review

    Energy Technology Data Exchange (ETDEWEB)

    Felderhoff, Michael [Max-Planck-Institut fuer Kohlenforschung, Muelheim an der Ruhr (Germany); Urbanczyk, Robert; Peil, Stefan [Institut fuer Energie- und Umwelttechnik e.V. (IUTA), Duisburg (Germany)

    2013-07-01

    Heat storage for high temperature applications can be performed by several heat storage techniques. Very promising heat storage methods are based on thermochemical gas solid reactions. Most known systems are metal oxide/steam (metal hydroxides), carbon dioxide (metal carbonates), and metal/hydrogen (metal hydrides) systems. These heat storage materials posses high gravimetric and volumetric heat storage densities and because of separation of the reaction products and their storage in different locations heat losses can be avoided. The reported volumetric heat storage densities are 615, 1340 and 1513 [ kWh m{sup -3}] for calcium hydroxide Ca(OH){sub 2}, calcium carbonate CaCO{sub 3} and magnesium iron hydride Mg{sub 2}FeH{sub 6} respectively. Additional demands for gas storage decrease the heat storage density, but metal hydride systems can use available hydrogen storage possibilities for example caverns, pipelines and chemical plants. (orig.)

  8. Solar thermoelectricity via advanced latent heat storage

    Science.gov (United States)

    Olsen, M. L.; Rea, J.; Glatzmaier, G. C.; Hardin, C.; Oshman, C.; Vaughn, J.; Roark, T.; Raade, J. W.; Bradshaw, R. W.; Sharp, J.; Avery, A. D.; Bobela, D.; Bonner, R.; Weigand, R.; Campo, D.; Parilla, P. A.; Siegel, N. P.; Toberer, E. S.; Ginley, D. S.

    2016-05-01

    We report on a new modular, dispatchable, and cost-effective solar electricity-generating technology. Solar ThermoElectricity via Advanced Latent heat Storage (STEALS) integrates several state-of-the-art technologies to provide electricity on demand. In the envisioned STEALS system, concentrated sunlight is converted to heat at a solar absorber. The heat is then delivered to either a thermoelectric (TE) module for direct electricity generation, or to charge a phase change material for thermal energy storage, enabling subsequent generation during off-sun hours, or both for simultaneous electricity production and energy storage. The key to making STEALS a dispatchable technology lies in the development of a "thermal valve," which controls when heat is allowed to flow through the TE module, thus controlling when electricity is generated. The current project addresses each of the three major subcomponents, (i) the TE module, (ii) the thermal energy storage system, and (iii) the thermal valve. The project also includes system-level and techno- economic modeling of the envisioned integrated system and will culminate in the demonstration of a laboratory-scale STEALS prototype capable of generating 3kWe.

  9. Heat in the Barents Sea: transport, storage, and surface fluxes

    Directory of Open Access Journals (Sweden)

    L. H. Smedsrud

    2010-02-01

    Full Text Available A column model is set up for the Barents Sea to explore sensitivity of surface fluxes and heat storage from varying ocean heat transport. Mean monthly ocean transport and atmospheric forcing are synthesised and force the simulations. Results show that by using updated ocean transports of heat and freshwater the vertical mean hydrographic seasonal cycle can be reproduced fairly well.

    Our results indicate that the ~70 TW of heat transported to the Barents Sea by ocean currents is lost in the southern Barents Sea as latent, sensible, and long wave radiation, each contributing 23–39 TW to the total heat loss. Solar radiation adds 26 TW in the south, as there is no significant ice production.

    The northern Barents Sea receives little ocean heat transport. This leads to a mixed layer at the freezing point during winter and significant ice production. There is little net surface heat loss annually in the north. The balance is achieved by a heat loss through long wave radiation all year, removing most of the summer solar heating.

    During the last decade the Barents Sea has experienced an atmospheric warming and an increased ocean heat transport. The Barents Sea responds to such large changes by adjusting temperature and heat loss. Decreasing the ocean heat transport below 50 TW starts a transition towards Arctic conditions. The heat loss in the Barents Sea depend on the effective area for cooling, and an increased heat transport leads to a spreading of warm water further north.

  10. Position paper -- Waste storage tank heat removal

    International Nuclear Information System (INIS)

    Stine, M.D.

    1995-01-01

    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

  11. Heat of Fusion Storage with High Solar Fraction for Solar Low Energy Buildings

    DEFF Research Database (Denmark)

    Schultz, Jørgen Munthe; Furbo, Simon

    The paper presents the results of a theoretical investigation of use of phase change materials (PCM’s) with active use of super cooling as a measure for obtaining partly heat loss free seasonal storages for solar combi-systems with 100% coverage of the energy demand of both space heating and dome......The paper presents the results of a theoretical investigation of use of phase change materials (PCM’s) with active use of super cooling as a measure for obtaining partly heat loss free seasonal storages for solar combi-systems with 100% coverage of the energy demand of both space heating...... and domestic hot water. The work is part of the IEA Solar Heating & Cooling Programme Task 32 “Advanced Storage Concepts for Solar Buildings”. The investigations are based on a newly developed TRNSYS type for simulation of a PCM-storage with controlled super-cooling. The super-cooling makes it possible to let...... storage parts already melted to cool down to surrounding temperature without solidification in which state that part of the storage will be heat loss free but still will hold the latent heat in form of the heat of fusion. At the time of energy demand the solidification of the super-cooled storage part...

  12. Performance analysis of phase-change material storage unit for both heating and cooling of buildings

    Science.gov (United States)

    Waqas, Adeel; Ali, Majid; Ud Din, Zia

    2017-04-01

    Utilisation of solar energy and the night ambient (cool) temperatures are the passive ways of heating and cooling of buildings. Intermittent and time-dependent nature of these sources makes thermal energy storage vital for efficient and continuous operation of these heating and cooling techniques. Latent heat thermal energy storage by phase-change materials (PCMs) is preferred over other storage techniques due to its high-energy storage density and isothermal storage process. The current study was aimed to evaluate the performance of the air-based PCM storage unit utilising solar energy and cool ambient night temperatures for comfort heating and cooling of a building in dry-cold and dry-hot climates. The performance of the studied PCM storage unit was maximised when the melting point of the PCM was ∼29°C in summer and 21°C during winter season. The appropriate melting point was ∼27.5°C for all-the-year-round performance. At lower melting points than 27.5°C, declination in the cooling capacity of the storage unit was more profound as compared to the improvement in the heating capacity. Also, it was concluded that the melting point of the PCM that provided maximum cooling during summer season could be used for winter heating also but not vice versa.

  13. Conception of a heat storage system for household applications. Category: New product innovations

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, Thomas [Leuphana Univ. Lueneburg (Germany); Rammelberg, Holger U.; Roennebeck, Thomas [and others

    2012-07-01

    Almost 90% of the energy consumption of private households in Germany is used for heating. Thus, an efficient, sustainable and reliable heat management is one of the main challenges in the future. Heat storage will become a key technology when considering the daily, weekly, seasonal and unpredictable fluctuations of energy production with renewables. The storage of heat is much more volume- and energy-efficient as well as more economical than electricity storage. However, transport of heat over long distances is coupled with high losses, compared with electricity transport. Therefore, we propose the use of micro CHP in combination with volume-efficient and nearly loss-free heat storage to counteract electricity fluctuations. Focus of this contribution the conception of the large-scale project ''Thermal Battery'', funded by the European Union and the Federal State of Lower Saxony. The underlying principle is the utilization of reversible thermochemical reactions, such as dehydration and rehydration of salt hydrates for heat storage. The main goal is the development of a prototypical storage tank, which is capable of storing 80 kWh of heat with a system volume of less than 1 m{sup 3}. Importantly, the Vattenfall New Energy Services as a collaboration partner will support the development of an application-oriented heat storage device. This project is being carried out by an interdisciplinary team of engineers, chemists, physicists and environmental scientists.

  14. Seasonal Deep Aquifer Thermal Energy Storage in the Gassum Sandstone Formation

    DEFF Research Database (Denmark)

    Holmslykke, H.D.H.; Kjøller, C.; Fabricius, Ida Lykke

    Seasonal storage of excess heat in hot deep aquifers is considered to optimise the usage of commonly available energy sources. The potential chemical reactions caused by heating the Gassum Sandstone Formation to up to 150°C is investigated by core flooding experiments combined with petrographic...... analysis and geochemical modelling. Synthetic formation water is injected into two sets of Gassum Formation samples at 25°C, 50°C (reservoir temperature), 100°C and 150°C with a velocity of 0.05 PV/hr and 0.1 PV/hr, respectively. A significant increase in the aqueous concentration of silicium and iron...

  15. Fiscal 1993 investigational report on heat pump heat storage technology; 1993 nendo heat pump chikunetsu gijutsu ni kansuru chosa hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-03-01

    This project is for an investigation into the heat pump (HP) use heat storage technology, with the aim of clarifying the present status of HP heat storage technology, the utilization status, and the developmental trend of technology and of contributing to the spread of heat energy effective use using HP heat storage technology and to the promotion of the technical development. Accordingly, the evaluation of the following was made: sensible heat (SH), latent heat (LH), chemical heat storage technology (CH), and heat storage technology (HS). Investigations were made on the sensible heat use heat storage technology of water, brine, stone, soil, etc. in terms of SH; the phase change sensible heat use heat storage technology of ice, hydrate salt, paraffins, etc. in terms of LH; hydration, hydroxide, 2-propanol pyrolysis, adsorption of silica gel, zeolite and water, and heat storage technology using metal hydride, etc. in terms of CH. In terms of HS, the following were studied and evaluated from the study results of the heat storage system in which HP is applied to the sensible heat and latent heat type heat storage technology: contribution to the power load levelling and the reduction of heat source capacity, heat recovery and the use of unused energy, improvement of the system efficiency by combining HP and heat storage technology. 24 refs., 242 figs., 56 tabs.

  16. Development of Latent Heat Storage Phase Change Material Containing Plaster

    Directory of Open Access Journals (Sweden)

    Diana BAJARE

    2016-05-01

    Full Text Available This paper reviews the development of latent heat storage Phase Change Material (PCM containing plaster as in passive application. Due to the phase change, these materials can store higher amounts of thermal energy than traditional building materials and can be used to add thermal inertia to lightweight constructions. It was shown that the use of PCMs have advantages stabilizing the room temperature variations during summer days, provided sufficient night ventilation is allowed. Another advantage of PCM usage is stabilized indoor temperature on the heating season. The goal of this study is to develop cement and lime based plaster containing microencapsulated PCM. The plaster is expected to be used for passive indoor applications and enhance the thermal properties of building envelope. The plaster was investigated under Scanning Electron Microscope and the mechanical, physical and thermal properties of created plaster samples were determined.

  17. Optimal study of a solar air heating system with pebble bed energy storage

    International Nuclear Information System (INIS)

    Zhao, D.L.; Li, Y.; Dai, Y.J.; Wang, R.Z.

    2011-01-01

    Highlights: → Use two kinds of circulation media in the solar collector. → Air heating and pebble bed heat storage are applied with different operating modes. → Design parameters of the system are optimized by simulation program. → It is found that the system can meet 32.8% of the thermal energy demand in heating season. → Annual solar fraction aims to be 53.04%. -- Abstract: The application of solar air collectors for space heating has attracted extensive attention due to its unique advantages. In this study, a solar air heating system was modeled through TRNSYS for a 3319 m 2 building area. This air heating system, which has the potential to be applied for space heating in the heating season (from November to March) and hot water supply all year around in North China, uses pebble bed and water storage tank as heat storage. Five different working modes were designed based on different working conditions: (1) heat storage mode, (2) heating by solar collector, (3) heating by storage bed, (4) heating at night and (5) heating by an auxiliary source. These modes can be operated through the on/off control of fan and auxiliary heater, and through the operation of air dampers manually. The design, optimization and modification of this system are described in this paper. The solar fraction of the system was used as the optimization parameter. Design parameters of the system were optimized by using the TRNSYS program, which include the solar collector area, installation angle of solar collector, mass flow rate through the system, volume of pebble bed, heat transfer coefficient of the insulation layer of the pebble bed and water storage tank, height and volume of the water storage tank. The TRNSYS model has been verified by data from the literature. Results showed that the designed solar system can meet 32.8% of the thermal energy demand in the heating season and 84.6% of the energy consumption in non-heating season, with a yearly average solar fraction of 53.04%.

  18. The impact of low-temperature seasonal aquifer thermal energy storage (SATES) systems on chlorinated solvent contaminated groundwater: Modeling of spreading and degradation

    NARCIS (Netherlands)

    Zuurbier, K.G.; Hartog, N.; Valstar, J.; Post, V.E.A.; Breukelen, B.M. van

    2013-01-01

    Groundwater systems are increasingly used for seasonal aquifer thermal energy storage (SATES) for periodic heating and cooling of buildings. Its use is hampered in contaminated aquifers because of the potential environmental risks associated with the spreading of contaminated groundwater, but

  19. The impact of short-term heat storage on the ice-albedo feedback loop

    Science.gov (United States)

    Polashenski, C.; Wright, N.; Perovich, D. K.; Song, A.; Deeb, E. J.

    2016-12-01

    The partitioning of solar energy in the ice-ocean-atmosphere environment is a powerful control over Arctic sea ice mass balance. Ongoing transitions of the sea ice toward a younger, thinner state are enhancing absorption of solar energy and contributing to further declines in sea ice in a classic ice-albedo feedback. Here we investigate the solar energy balance over shorter timescales. In particular, we are concerned with short term delays in the transfer of absorbed solar energy to the ice caused by heat storage in the upper ocean. By delaying the realization of ice melt, and hence albedo decline, heat storage processes effectively retard the intra-season ice-albedo feedback. We seek to quantify the impact and variability of such intra-season storage delays on full season energy absorption. We use in-situ data collected from Arctic Observing Network (AON) sea ice sites, synthesized with the results of imagery processed from high resolution optical satellites, and basin-scale remote sensing products to approach the topic. AON buoys are used to monitor the storage and flux of heat, while satellite imagery allows us to quantify the evolution of surrounding ice conditions and predict the aggregate scale solar absorption. We use several test sites as illustrative cases and demonstrate that temporary heat storage can have substantial impacts on seasonal energy absorption and ice loss. A companion to this work is presented by N. Wright at this meeting.

  20. Investigation on Solar Heating System with Building-Integrated Heat Storage

    DEFF Research Database (Denmark)

    Heller, Alfred

    1996-01-01

    Traditional solar heating systems cover between 5 and 10% of the heat demand fordomestic hot water and comfort heating. By applying storage capacity this share can beincreased much. The Danish producer of solar heating systems, Aidt-Miljø, markets such a system including storage of dry sand heated...... by PP-pipe heat exchanger. Heat demand is reduced due to direct solar heating and due to storage. The storage affects the heat demand passively due to higher temperatures. Hence heat loss is reduced and passive heating is optioned. In theory, by running the system flow backwards, active heating can...... solar collector area of the system, was achieved. Active heating from the sand storage was not observed. The pay-back time for the system can be estimated to be similar to solar heated domestic hot water systems in general. A number of minor improvements on the system could be pointed out....

  1. Latent heat coldness storage; Stockage du froid par chaleur latente

    Energy Technology Data Exchange (ETDEWEB)

    Dumas, J.P. [Pau Univ., Lab. de Thermodynamique et Energetique, LTE, 64 (France)

    2002-07-01

    This article presents the advantages of latent heat storage systems which use the solid-liquid phase transformation of a pure substance or of a solution. The three main methods of latent heat storage of coldness are presented: ice boxes, encapsulated nodules, and ice flows: 1 - definition of the thermal energy storage (sensible heat, latent heat, thermochemical storage); 2 - advantages and drawbacks of latent heat storage; 3 - choice criteria for a phase-change material; 4 - phenomenological aspect of liquid-solid transformations (phase equilibrium, crystallisation and surfusion); 5 - different latent heat storage processes (ice boxes, encapsulated nodules, two-phase refrigerating fluids); 6 - ice boxes (internal and external melting, loop, air injection, measurement of ice thickness); 7 - encapsulated nodules (nodules, tank, drainage, advantage and drawbacks, charge and discharge); 8 - two-phase refrigerating fluids (composition, ice fabrication, flow circulation, flow storage, exchangers). (J.S.)

  2. Seasonal variation of heat consumption in greenhouses

    DEFF Research Database (Denmark)

    Nielsen, O.F.; Amsen, M.G.; Strøm, J.S.

    The concept of dynamic variation is introduced as a method to visualize the dynamic fluctuations of heat consumption and thermal climate in greenhouses. The feasibility of the concept is illustrated by describing effects of different greenhouse designs. Engineering data on design heat consumption...

  3. Long-term heat storage in calcium sulfoaluminate cement (CSA) based concrete

    Energy Technology Data Exchange (ETDEWEB)

    Kaufmann, Josef P.; Winnefeld, Frank [Empa Swiss Federal Laboratories for Materials Science and Technology, Duebendorf (Switzerland). Lab. for Concrete and Construction Chemistry

    2011-07-01

    In general, the selection of materials proposed for solar heat storage is based on one of two principal processes: sensible heat storage or latent heat storage. Sensible heat storage utilizes the specific heat capacity of a material, while latent heat storage is based on the change in enthalpy (heat content) associated with a phase change of the material. Long time sensible heat storage requires excellent thermal insulation whereas latent heat storage allows permanent (seasonal) storage without significant energy losses and any special insulation. Ettringite, one of the cement hydration products, exhibits a high dehydration enthalpy. Calcium sulfoaluminate cement based concrete containing a high amount of ettringite is henceproposed as an efficient latent heat storage material. Compared to conventional heat storage materials this innovative concrete mixture has a high loss-free storage energy density (> 100-150 kWh/m{sup 3}) which is much higher than the one of paraffin or the (loss-sensitive) sensible heat of water. Like common concrete the CSA-concrete is stable and even may carry loads. The dehydration of the CSA-concrete is achieved at temperatures below 100 C. The rehydration process occurs as soon as water (liquid or vapor) is added. In contrast to paraffin, the phase change temperature is not fixed and the latent heat may be recovered at any desired temperature. Furthermore the heat conductivity of this material is high, so that the energy transfer from/to an exchange medium is easy. Additionally CSA-concrete is not flammable and absolutely safe regarding any health aspects. The cost of such CSA-concrete isin the order of normal concrete. The main application is seen in house heating systems. Solar heat, mostly generated during the summer period by means of roof collectors, can be stored in CSA-concrete until the winter. A part or even the whole annual heatingenergy may be produced and saved locally by the householder himself. Additional applications may be

  4. Experimental device for the residential heating with heat pipe and electric heat storage blocks

    Energy Technology Data Exchange (ETDEWEB)

    Vasiliev, L L; Boldak, I M; Domorod, L S; Rabetsky, M I; Schirokov, E I [AN Belorusskoj SSR, Minsk (Belarus). Inst. Teplo- i Massoobmena

    1992-01-01

    Residential heating using electric heat storage blocks nowadays is an actual problem from the point of view of heat recovery and nature protection. In the Luikov Heat and Mass Transfer Institute a new residential electrical heater capable of heating chambers by controlling air temperature and heat output using heat pipes and an electric heat storage block was developed. This heater (BETA) is fed from the source of energy and during 7 h of night time accumulates energy sufficiently to heat 10 m{sup 3} during 24 h. Heating device BETA has a ceramic thermal storage block, electric heaters and a heat pipe with evaporator inside the ceramic block and constant temperature (65{sup o}C) finned condenser outside it. The condenser temperature could be controlled easily. BETA is compact, has high thermal response, accurate air temperature control and safe operation. Such types of residential heaters are necessary for heating residential and office building in the Mogilev and Gomel regions in Byelorussia which suffered after the Chernobyl catastrophe. (Author).

  5. THERMOCHEMICAL HEAT STORAGE FOR CONCENTRATED SOLAR POWER

    Energy Technology Data Exchange (ETDEWEB)

    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

  6. Bibliography of the seasonal thermal energy storage library

    Energy Technology Data Exchange (ETDEWEB)

    Prater, L.S.; Casper, G.; Kawin, R.A.

    1981-08-01

    The Main Listing is arranged alphabetically by the last name of the first author. Each citation includes the author's name, title, publisher, publication date, and where applicable, the National Technical Information Service (NTIS) number or other document number. The number preceding each citation is the identification number for that document in the Seasonal Thermal Energy Storage (STES) Library. Occasionally, one or two alphabetic characters are added to the identification number. These alphabetic characters indicate that the document is contained in a collection of papers, such as the proceedings of a conference. An Author Index and an Identification Number Index are included. (WHK)

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

    International Nuclear Information System (INIS)

    Singh, Randeep; Mochizuki, Masataka; Mashiko, Koichi; Nguyen, Thang

    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 energy storage will help to reduce the chiller running time that will save electricity related cost and decrease greenhouse gas emissions resulting from the electricity generation from non-renewable sources. The proposed cold energy storage system can be retrofit or connected in the existing datacenter facilities without major design changes. Out of the two proposed systems, ice based cold energy storage system is mainly recommended for datacenters which are located in very cold locations and therefore can offer long term seasonal storage of cold energy within reasonable cost. One of the potential application domains for ice based cold energy storage system using heat pipes is the emergency backup system for datacenter. Water based cold energy storage system provides more compact size with short term storage (hours to days) and is potential for datacenters located in areas with yearly average temperature below the permissible cooling water temperature (∼25 o C). The aforesaid cold energy storage systems were sized on the basis of metrological conditions in Poughkeepsie, New York. As an outcome of the thermal and cost analysis, water based cold energy storage system with cooling capability to handle 60% of datacenter yearly heat load will provide an optimum system size with minimum payback period of 3.5 years. Water based cold energy storage system using heat pipes can be essentially used as precooler for chiller. Preliminary results obtained from the experimental system to test the capability of heat pipe based cold energy storage system have provided satisfactory outcomes and validated the proposed

  8. Device for storage of radio-nuclide configurations releasing heat

    International Nuclear Information System (INIS)

    Schoenfeld, R.; Jeschar, R.; Tenhumberg, M.

    1985-01-01

    In dry intermediate storage of burnt-up fuel elements and HAN, the storage shafts have cooling air flowing through them in the axial direction. The lids of the storage cells are made into heat exchangers via the outer cooling air circulation. Inside the storage cells, vertical, spatially and functionally separate updraught and downdraught chimneys are situated at the openings of the storage shafts. To force a convection flow of the right direction inside the storage cells, the lid or the storage shafts are inclined in the direction of the downdraught chimney or the storage shafts are provided with flow obstructions favouring one direction. (orig./HP) [de

  9. Quantification of the reactions in heat storage systems in the Malm aquifer

    Science.gov (United States)

    Ueckert, Martina; Baumann, Thomas

    2017-04-01

    Combined heat and power plants (CHP) are efficient and environmentally friendly because excess heat produced during power generation is used for heating purposes. While the power demand remains rather constant throughout the year, the heat demand shows seasonal variations. In a worst-case scenario, the heat production in winter is not sufficient, and the power production in summer has to be ramped down because the excess heat cannot be released to the environment. Therefore, storage of excess heat of CHP is highly beneficial from an economic and an ecological point of view. Aquifer thermal energy storage (ATES) is considered as a promising technology for energy storage. In a typical setting, water from an aquifer is produced, heated up by excess heat from the CHP and injected through a second borehole back into the aquifer. The carbonate rocks of the upper Jurrasic in the Molasse Basin seem to be promising sites for aquifer heat storage because of their high transmissivity combined with a typical geological setting with tight caprock. However, reactions in the aquifer cannot be neglected and may become the limiting process of the whole operation. While there have been several studies performed in clastic aquifers and for temperatures below 100°C, the knowledge about high injection temperatures and storage into a carbonatic aquifer matrix is still limited. Within a research project funded by the Bavarian State Ministry for Economic Affairs and the BMW Group, the storage and recuperation of excess heat energy into the Bavarian Malm aquifer with flow rates of 15 L/s and temperatures of up to 110°C was investigated. The addition of {CO_2} was used to prevent precipitations. Data from the field site was backed up by autoclave experiments and used to verify a conceptional hydrogeochemical model with PhreeqC for the heat storage operation. The model allows to parametrize the operation and to predict possible reactions in the aquifer.

  10. Heat pumps combined with cold storage; Warmtepompen gecombineerd met koudeopslag

    Energy Technology Data Exchange (ETDEWEB)

    Van Ingen, M.A. [Techniplan Adviseurs, Rotterdam (Netherlands)

    1999-09-01

    The architects of the new Nike head office building in Hilversum, Netherlands, opted for a heat pump combined with a cold storage system. The most efficient design was found to be a single central location for the production of heat and cold, with distribution lines to each of the five buildings. The cold storage system provides direct cooling and indirect heating: the heat pump raises the low-temperature heat from the cold storage to a usable temperature (augmented by district heating when necessary). In addition, the heat pump generates cold as a by-product in winter, which can be stored in the sources system and utilised during the following summer. The heat pump can also be used for cooling, for peak load supply and for any short-term storage requirement in emergencies

  11. Seasonal energy storage using bioenergy production from abandoned croplands

    International Nuclear Information System (INIS)

    Elliott Campbell, J; Zumkehr, Andrew; Lobell, David B; Genova, Robert C; Field, Christopher B

    2013-01-01

    Bioenergy has the unique potential to provide a dispatchable and carbon-negative component to renewable energy portfolios. However, the sustainability, spatial distribution, and capacity for bioenergy are critically dependent on highly uncertain land-use impacts of biomass agriculture. Biomass cultivation on abandoned agriculture lands is thought to reduce land-use impacts relative to biomass production on currently used croplands. While coarse global estimates of abandoned agriculture lands have been used for large-scale bioenergy assessments, more practical technological and policy applications will require regional, high-resolution information on land availability. Here, we present US county-level estimates of the magnitude and distribution of abandoned cropland and potential bioenergy production on this land using remote sensing data, agriculture inventories, and land-use modeling. These abandoned land estimates are 61% larger than previous estimates for the US, mainly due to the coarse resolution of data applied in previous studies. We apply the land availability results to consider the capacity of biomass electricity to meet the seasonal energy storage requirement in a national energy system that is dominated by wind and solar electricity production. Bioenergy from abandoned croplands can supply most of the seasonal storage needs for a range of energy production scenarios, regions, and biomass yield estimates. These data provide the basis for further down-scaling using models of spatially gridded land-use areas as well as a range of applications for the exploration of bioenergy sustainability. (letter)

  12. Wind power integration using individual heat pumps – Analysis of different heat storage options

    DEFF Research Database (Denmark)

    Hedegaard, Karsten; Mathiesen, Brian Vad; Lund, Henrik

    2012-01-01

    Significant installations of individual heat pumps are expected in future energy systems due to their economic competitiveness. This case study of the Danish energy system in 2020 with 50% wind power shows that individual heat pumps and heat storages can contribute to the integration of wind power....... Heat accumulation tanks and passive heat storage in the construction are investigated as two alternative storage options in terms of their ability to increase wind power utilisation and to provide cost-effective fuel savings. Results show that passive heat storage can enable equivalent to larger...... reductions in excess electricity production and fuel consumption than heat accumulation tanks. Moreover, passive heat storage is found to be significantly more cost-effective than heat accumulation tanks. In terms of reducing fuel consumption of the energy system, the installation of heat pumps is the most...

  13. Thermal energy storage - A review of concepts and systems for heating and cooling applications in buildings

    DEFF Research Database (Denmark)

    Pavlov, Georgi Krasimiroy; Olesen, Bjarne W.

    2012-01-01

    period required, economic viability, and operating conditions. One of the main issues impeding the utilization of the full potential of natural and renewable energy sources, e.g., solar and geothermal, for space heating and space cooling applications is the development of economically competitive......The use of thermal energy storage (TES) in buildings in combination with space heating and/or space cooling has recently received much attention. A variety of TES techniques have developed over the past decades. TES systems can provide short-term storage for peak-load shaving as well as long......-term (seasonal) storage for the introduction of natural and renewable energy sources. TES systems for heating or cooling are utilized in applications where there is a time mismatch between the demand and the most economically favorable supply of energy. The selection of a TES system mainly depends on the storage...

  14. Experimental investigation for the optimization of heat pipe performance in latent heat thermal storage

    Energy Technology Data Exchange (ETDEWEB)

    Ladekar, Chandrakishor; Choudhary, S. K. [RTM Nagpur University, Wardha (India); Khandare, S. S. [B. D. College of Engineering, Wardha (India)

    2017-06-15

    We investigated the optimum performance of heat pipe in Latent heat thermal energy storage (LHTES), and compared it with copper pipe. Classical plan of experimentation was used to optimize the parameters of heat pipe. Heat pipe fill ratio, evaporator section length to condenser section length ratio i.e., Heat pipe length ratio (HPLR) and heat pipe diameter, was the parameter used for optimization, as result of parametric analysis. Experiment with flow rate of 10 lit./min. was conducted for different fill ratio, HPLR and different diameter. Fill ratio of 80 %, HPLR of 0.9 and heat pipe with diameter of 18 mm showed better trend in charging and discharging. Comparison between the storage tank with optimized heat pipe and copper pipe showed almost 186 % improvement in charging and discharging time compared with the copper pipe embedded thermal storage. Heat transfer between Heat transferring fluid (HTF) and Phase change material (PCM) increased with increase in area of heat transferring media, but storage density of storage tank decreased. Storage tank with heat pipe embedded in place of copper pipe is a better option in terms of charging and discharging time as well heat storage capacity due to less heat lost. This justifies the better efficiency and effectiveness of storage tank with embedded optimized heat pipe.

  15. Anomalous Heat Budgets in the Interior Pacific Ocean on Seasonal- to -Timescales and Gyre Spacescales

    Science.gov (United States)

    White, Warren; Cayan, Daniel R.; Lindstrom, Eric (Technical Monitor)

    2002-01-01

    This study quantifies uncertainties in closing the seasonal cycle of diabatic heat storage over the Pacific Ocean from 20 degrees S to 60 degrees N through the synthesis of World Ocean Circulation Experiment (WOCE) products over 7 years from 1993-1999. We utilize WOCE reanalysis products from the following sources: diabatic heat storage (DHS) from the Scripps Institution of Oceanography (SIO); near-surface geostrophic and Ekman currents from the Earth and Space Research (ESR); and air-sea heat fluxes from Comprehensive Ocean-Atmosphere Data Set (COADS), National Centers for Environmental Prediction (NCEP), and European Center for Mid-Range Weather Forecasts (ECMWF). We interpolate these products onto a common grid, allowing the seasonal cycle of DHS to be modeled for comparison with that observed. Everywhere latent heat flux residuals dominate sensible heat flux residuals and shortwave heat flux residuals dominate longwave heat flux residuals, both comparable in magnitude to the residual horizontal heat advection. We find the root-mean-square (RMS) of the differences between observed and model residual DHS tendencies to be less than 15 W per square meters everywhere except in the Kuroshio extension. Comparable COADS and NCEP products perform better than ECMWF products in the extra-tropics, while the NCEP product performs best in the tropics. Radiative and turbulent air-sea heat flux residuals computed from ship-born measurements perform better than those computed from satellite cloud and wind measurements. Since the RMS differences derive largely from biases in measured wind speed and cloud fraction, least-squares minimization is used to correct the residual Ekman heat advection and air-sea heat flux. Minimization reduces RMS differences less than 5 W per square meters except in the Kuroshio extension, suggesting how winds, clouds, and exchange coefficients in the NCEP, ECMWF, and ESR products can be improved.

  16. Quality of second season soybean submitted to drying and storage

    Directory of Open Access Journals (Sweden)

    Cesar Pedro Hartmann Filho

    2016-09-01

    Full Text Available Drying agricultural products reduces the moisture content to suitable levels for storage, in order to maintain the product quality. However, special care with the temperatures applied in the process is important for the integrity and longevity of the material. The present study aimed at determining the immediate and latent effect of air-drying temperatures on the quality of soybean produced as a second season crop. The grains were collected at the R8 stage, close to the physiological maturity, with moisture content of approximately 23 % (w.b., submitted to drying temperatures of 40 ºC, 50 ºC, 60 ºC, 70 ºC and 80 ºC, up to a moisture content of 12.5 ± 0.7 % (w.b., and then stored under non-controlled humidity and temperature for 180 days. Thereafter, quality was assessed every 45 days by determining the dry matter loss, color and crude protein and lipid contents, as well as the acidity and peroxide indices of the crude oil extracted. Based on the results obtained, it was concluded that the increase in the air-drying temperature affects the soybean quality and crude oil extracted, being this effect enhanced with the storage time; the soybean and crude oil quality decline with an increase in the air-drying temperature and storage time; the air temperature of 40 ºC has the least effect on the quality of soybean grains and crude oil extracted.

  17. A solar air collector with integrated latent heat thermal storage

    Directory of Open Access Journals (Sweden)

    Klimes Lubomir

    2012-04-01

    Full Text Available Simulations of the behaviour of a solar air collector with integrated latent heat thermal storage were performed. The model of the collector was created with the use of coupling between TRNSYS 17 and MATLAB. Latent heat storage (Phase Change Material - PCM was integrated with the solar absorber. The model of the latent heat storage absorber was created in MATLAB and the model of the solar air collector itself was created in TRNSYS with the use of TYPE 56. The model of the latent heat storage absorber allows specification of the PCM properties as well as other parameters. The simulated air collector was the front and back pass collector with the absorber in the middle of the air cavity. Two variants were considered for comparison; the light-weight absorber made of sheet metal and the heat-storage absorber with the PCM. Simulations were performed for the climatic conditions of the Czech Republic (using TMY weather data.

  18. Design of annual storage solar space heating systems

    Energy Technology Data Exchange (ETDEWEB)

    Hooper, F C; Cook, J D

    1979-11-01

    Design considerations for annual storage solar space heating systems are discussed. A simulation model for the performance of suh systems is described, and a method of classifying system configurations is proposed. It is shown that annual systems sized for unconstrained performance, with no unused collector or storage capacity, and no rejected heat, minimize solar acquisition costs. The optimal performance corresponds to the condition where the marginal storage-to-collector sizing ratio is equal to the corresponding marginal cost ratio.

  19. Thermal performance and heat transport in aquifer thermal energy storage

    NARCIS (Netherlands)

    Sommer, W.T.; Doornenbal, P.J.; Drijver, B.C.; Gaans, van P.F.M.; Leusbrock, I.; Grotenhuis, J.T.C.; Rijnaarts, H.H.M.

    2014-01-01

    Aquifer thermal energy storage (ATES) is used for seasonal storage of large quantities of thermal energy. Due to the increasing demand for sustainable energy, the number of ATES systems has increased rapidly, which has raised questions on the effect of ATES systems on their surroundings as well as

  20. Heat storage. Role in the energy system of the future

    International Nuclear Information System (INIS)

    Hauer, Andreas; Woerner, Antje; Kranz, Stefan; Schumacher, Patrick; Gschwander, Stefan; Appen, Jan von; Hidalgo, Diego; Gross, Bodo; Grashof, Katherina

    2015-01-01

    For the implementation of the energy transition in Germany can contribute in a variety of applications thermal energy storage. Both at the integration of renewable energy sources, as well as in increasing the energy efficiency in the building sector and industry can utilize heat and cold storage great potential. For this diverse storage technologies are available. In Germany numerous research and development projects are running currently, covering the broad possibilities of thermal energy storage. [de

  1. Seasonal thermal energy storage in shallow geothermal systems: thermal equilibrium stage

    Directory of Open Access Journals (Sweden)

    Nowamooz Hossein

    2016-01-01

    Full Text Available This paper is dedicated to the study of seasonal heat storage in shallow geothermal installations in unsaturated soils for which hydrothermal properties such as degree of saturation and thermal conductivity vary with time throughout the profile. In the model, a semi-analytical model which estimates time-spatial thermal conductivity is coupled with a 2D cylindrical heat transfer modeling using finite difference method. The variation of temperature was obtained after 3 heating and cooling cycles for the different types of loads with maximum thermal load of qmax = 15 W.m−1 with variable angular frequency (8 months of heating and 4 months of cooling.and constant angular frequency (6 months of heating and 6 months of cooling to estimate the necessary number of cycles to reach the thermal equilibrium stage. The results show that we approach a thermal equilibrium stage where the same variation of temperature can be observed in soils after several heating and cooling cycles. Based on these simulations, the necessary number of cycles can be related to the total applied energy on the system and the minimum number of cycles is for a system with the total applied energy of 1.9qmax.

  2. Chemical heat pump and chemical energy storage system

    Science.gov (United States)

    Clark, Edward C.; Huxtable, Douglas D.

    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.

  3. Simulation of gas supply and consumption during heating season; Simulacija opskrbe potrosaca plinom tijekom ogrjevne sezone

    Energy Technology Data Exchange (ETDEWEB)

    Oklopcic, Z [INA-Naftaplin, Zagreb (Croatia)

    1997-12-31

    In this paper stochastic simulation model of gas supply and consumption during heating season is described. The simulation of gas supply is based on constant import and domestic production and varying production of underground storage which depends on current needs and quantity of gas in the storage. The basis for consumption simulation is the stochastic relationship between gas consumption and mean daily air temperature and type of the day, expressed in the form of linear regression model. Mean daily air temperatures, as one of basic causes of daily gas consumption variations, are simulated, on the basis of statistical characteristics and own air temperature measurements, as a first order autoregression model. By using the developed simulation model the statistical characteristics (expectation, standard deviation) of daily gas consumption and the difference between maximum possible daily supply and consumption (delivery safety margin) are derived for all days in the season. The definition of gas delivery safety is given and critical delivery probabilities for all days in the season and different safety margins are determined. Also, statistical characteristics of critical delivery duration depending on gas reserves status for underground storage is predicted. Predicted gas storage delivery rate is compared against predicted requirements, and on the basis of this comparison possible bottlenecks in gas delivery to consumers and course of future actions are indicated. (author). 3 tabs., 10 figs., 6 refs.

  4. Integration of Decentralized Thermal Storages Within District Heating (DH Networks

    Directory of Open Access Journals (Sweden)

    Schuchardt Georg K.

    2016-12-01

    Full Text Available Thermal Storages and Thermal Accumulators are an important component within District Heating (DH systems, adding flexibility and offering additional business opportunities for these systems. Furthermore, these components have a major impact on the energy and exergy efficiency as well as the heat losses of the heat distribution system. Especially the integration of Thermal Storages within ill-conditioned parts of the overall DH system enhances the efficiency of the heat distribution. Regarding an illustrative and simplified example for a DH system, the interactions of different heat storage concepts (centralized and decentralized and the heat losses, energy and exergy efficiencies will be examined by considering the thermal state of the heat distribution network.

  5. The influence of heat sink temperature on the seasonal efficiency of shallow geothermal heat pumps

    Science.gov (United States)

    Pełka, Grzegorz; Luboń, Wojciech; Sowiżdżał, Anna; Malik, Daniel

    2017-11-01

    Geothermal heat pumps, also known as ground source heat pumps (GSHP), are the most efficient heating and cooling technology utilized nowadays. In the AGH-UST Educational and Research Laboratory of Renewable Energy Sources and Energy Saving in Miękinia, shallow geothermal heat is utilized for heating. In the article, the seasonal efficiency of two geothermal heat pump systems are described during the 2014/2015 heating season, defined as the period between 1st October 2014 and 30th April 2015. The first system has 10.9 kW heating capacity (according to European Standard EN 14511 B0W35) and extracts heat from three vertical geothermal loops at a depth of 80m each. During the heating season, tests warmed up the buffer to 40°C. The second system has a 17.03 kW heating capacity and extracts heat from three vertical geothermal loops at a depth of 100 m each, and the temperature of the buffer was 50°C. During the entire heating season, the water temperatures of the buffers was constant. Seasonal performance factors were calculated, defined as the quotient of heat delivered by a heat pump to the system and the sum of electricity consumed by the compressor, source pump, sink pump and controller of heat pumps. The measurements and calculations give the following results: - The first system was supplied with 13 857 kWh/a of heat and consumed 3 388 kWh/a electricity. The SPF was 4.09 and the average temperature of outlet water from heat pump was 40.8°C, and the average temperature of brine flows into the evaporator was 3.7 °C; - The second system was supplied with 12 545 kWh/a of heat and consumed 3 874 kWh/a electricity. The SPF was 3.24 and the average temperature of outlet water from heat pump was 51.6°C, and the average temperature of brine flows into the evaporator was 5.3°C. To summarize, the data shown above presents the real SPF of the two systems. It will be significant in helping to predict the SPF of objects which will be equipped with ground source heat pumps.

  6. Slow heat release - solid fuel stove with acetat-trihydrate heat storage sodium; Slow heat release - Braendeovn med salthydratvarmelager

    Energy Technology Data Exchange (ETDEWEB)

    Zielke, U.; Bjerrum, M.; Noergaard, T. (Teknologisk Institut, Aarhus (Denmark))

    2012-07-01

    Of the 700,000 solid fuel stoves in Denmark, 600,000 are installed in permanent residences, and 100,000 are installed in summer cottages. Recent examinations have shown that in the heating season, these stoves contribute with a not negligible share of air pollution in the cities. The reason is often inexpedient firing and an inappropriate performance of the stove. In many cases the thermal output of the stove exceeds the heating demand of a modern residence; and the user typically reduces the stove's combustion air supply with the purpose of lowering the temperature of the accommodation space. The result is a sooting combustion followed by undesired and environmentally damaging emissions. In worst case the user fires throughout the night reducing the air to an absolutely minimum. In these situations the fuel smoulders all night, and the stove emits large amounts of undesirable and unhealthy emissions. By constructing the stove with a heat storage that can accumulate the heat from the stove and emit the heat later (when not firing), the problem with the unhealthy ''night firings'' should be eliminated. The project started with a pre-examination regarding suitable materials for a heat storage and a literature study of the subject. By using an OGC material, in this case sodiumacetat-trihydrat, the weight of the stove, in spite of the heat storage, could be held within reasonable frames, since 130 kg PCM can contain the same heat amount as 1,200 kg stone. The great challenge was to compensate for PCM's poor heat conductivities, to distribute the heat in the whole heat storage, making it melt regularly without generating local boiling. This problem was solved by construction measures. The system with sodiumacetat-trihydrat, which melts by 58 deg. C, came to function satisfactorily. 14 hours after the last firing, the temperature of the heat storage was 30 deg. C. The tests with PCM were followed by an extensive emission measuring program

  7. Residential Solar-Based Seasonal Thermal Storage Systems in Cold Climates: Building Envelope and Thermal Storage

    Directory of Open Access Journals (Sweden)

    Alexandre Hugo

    2012-10-01

    Full Text Available The reduction of electricity use for heating and domestic hot water in cold climates can be achieved by: (1 reducing the heating loads through the improvement of the thermal performance of house envelopes, and (2 using solar energy through a residential solar-based thermal storage system. First, this paper presents the life cycle energy and cost analysis of a typical one-storey detached house, located in Montreal, Canada. Simulation of annual energy use is performed using the TRNSYS software. Second, several design alternatives with improved thermal resistance for walls, ceiling and windows, increased overall air tightness, and increased window-to-wall ratio of South facing windows are evaluated with respect to the life cycle energy use, life cycle emissions and life cycle cost. The solution that minimizes the energy demand is chosen as a reference house for the study of long-term thermal storage. Third, the computer simulation of a solar heating system with solar thermal collectors and long-term thermal storage capacity is presented. Finally, the life cycle cost and life cycle energy use of the solar combisystem are estimated for flat-plate solar collectors and evacuated tube solar collectors, respectively, for the economic and climatic conditions of this study.

  8. Solar and seasonal dependence of ion frictional heating

    Directory of Open Access Journals (Sweden)

    J. A. Davies

    1999-05-01

    Full Text Available Ion frictional heating constitutes one of the principal mechanisms whereby energy, originating in the solar wind, is deposited into the Earth's ionosphere and ultimately the neutral atmosphere. Common programme observations by the EISCAT UHF radar system, spanning the years 1984 to 1995, provide the basis for a comprehensive statistical study of ion frictional heating, results of which are documented in this and a previous paper by the authors. In the present work, the authors demonstrate the solar and seasonal dependence of the universal time distribution of frictional heating, and explain these results with reference to corresponding dependences of the ion velocity. Although EISCAT observes a significant increase in the occurrence of enhanced ion velocities associated with increased solar activity, the latter characterised according to the prevailing 10.7 cm solar flux, this is not reflected to such an extent in the occurrence of frictional heating. It is suggested that this is a consequence of the decreased neutral atmosphere response times associated with active solar conditions, resulting from the higher ionospheric plasma densities present. Seasonal effects on the diurnal distribution of ion frictional heating are well explained by corresponding variations in ionospheric convection, the latter principally a result of geometrical factors. It is noted that, over the entire dataset, the variations in the unperturbed F-region ion temperature, required to implement the identification criterion for ion heating, are highly correlated with model values of thermospheric temperature.Keywords. Ionosphere (auroral ionosphere; ionosphere-atmosphere interactions; plasma temperature and density

  9. Heat-pump cool storage in a clathrate of freon

    Science.gov (United States)

    Tomlinson, J. J.

    Presented are the analytical description and assessment of a unique heat pump/storage system in which the conventional evaporator of the vapor compression cycle is replaced by a highly efficient direct contract crystallizer. The thermal storage technique requires the formation of a refrigerant gas hydrate (a clathrate) and exploits an enthalpy of reaction comparable to the heat of fusion of ice. Additional system operational benefits include cool storage at the favorable temperatures of 4 to 7 C (40 to 45 F), and highly efficient heat transfer ates afforded by he direct contact mechanism. In addition, the experimental approach underway at ORNL to study such a system is discussed.

  10. Marketing research on heat storage in aquifers. Systems, applications and combinations with heat generating techniques, and sector potentials. Marktorientatie warmte-opslag in aquifers. Systemen, toepassingen en combinaties met warmte-producerende technieken, deelsector potentielen

    Energy Technology Data Exchange (ETDEWEB)

    1987-01-01

    The market research on the title subject concentrates on the possible applications of seasonal heat storage for space heating in buildings (not industrial). Some selected heat storage systems in aquifers were analyzed with regard to the state of the technology, minimal storage capacity and the price/performance ratio. Then a number of co binations with bridging techniques has been investigated: combinations with cogeneration systems, heat pumps or solar energy systems. Finally the potentials of energy conservation in non-industrial buildings for small-scale and large-scale heat storage are listed. 6 figs., 16 refs., 24 tabs., 9 apps.

  11. A state-of-the-art review on hybrid heat pipe latent heat storage systems

    International Nuclear Information System (INIS)

    Naghavi, M.S.; Ong, K.S.; Mehrali, M.; Badruddin, I.A.; Metselaar, H.S.C.

    2015-01-01

    The main advantage of latent heat thermal energy storage systems is the capability to store a large quantity of thermal energy in an isothermal process by changing phase from solid to liquid, while the most important weakness of these systems is low thermal conductivity that leads to unsuitable charging/discharging rates. Heat pipes are used in many applications – as one of the most efficient heat exchanger devices – to amplify the charging/discharging processes rate and are used to transfer heat from a source to the storage or from the storage to a sink. This review presents and critically discusses previous investigations and analysis on the incorporation of heat pipe devices into latent heat thermal energy storage with heat pipe devices. This paper categorizes different applications and configurations such as low/high temperature solar, heat exchanger and cooling systems, analytical approaches and effective parameters on the performance of hybrid HP–LHTES systems.

  12. Seasonal water storage, stress modulation and California seismicity

    Science.gov (United States)

    Johnson, C. W.; Burgmann, R.; Fu, Y.

    2017-12-01

    Establishing what controls the timing of earthquakes is fundamental to understanding the nature of the earthquake cycle and critical to determining time-dependent earthquake hazard. Seasonal loading provides a natural laboratory to explore the crustal response to a quantifiable transient force. In California, the accumulation of winter snowpack in the Sierra Nevada, surface water in lakes and reservoirs, and groundwater in sedimentary basins follow the annual cycle of wet winters and dry summers. The surface loads resulting from the seasonal changes in water storage produce elastic deformation of the Earth's crust. We used 9 years of global positioning system (GPS) vertical deformation time series to constrain models of monthly hydrospheric loading and the resulting stress changes on fault planes of small earthquakes. Previous studies posit that temperature, atmospheric pressure, or hydrologic changes may strain the lithosphere and promote additional earthquakes above background levels. Depending on fault geometry, the addition or removal of water increases the Coulomb failure stress. The largest stress amplitudes are occurring on dipping reverse faults in the Coast Ranges and along the eastern Sierra Nevada range front. We analyze 9 years of M≥2.0 earthquakes with known focal mechanisms in northern and central California to resolve fault-normal and fault-shear stresses for the focal geometry. Our results reveal 10% more earthquakes occurring during slip-encouraging fault-shear stress conditions and suggest that earthquake populations are modulated at periods of natural loading cycles, which promote failure by stress changes on the order of 1-5 kPa. We infer that California seismicity rates are modestly modulated by natural hydrological loading cycles.

  13. Field evaluation and assessment of thermal energy storage for residential space heating

    Science.gov (United States)

    Hersh, H. N.

    1982-02-01

    A data base was developed based on two heating seasons and 45 test and 30 control homes in Maine and Vermont. Based on first analysis of monitored temperatures and electrical energy used for space heating, fuel bills and reports of users and utilities, the technical performance of TES ceramic and hydronic systems is deemed to be technically satisfactory and there is a high degree of customer acceptance and positive attitudes towards TES. Analysis of house data shows a high degree of variability in electric heat energy demand for a given degree-day. An analysis is underway to investigate relative differences in the efficiency of electricity utilization of storage and direct heating devices. The much higher price of storge systems relative to direct systems is an impediment to market penetration. A changing picture of rate structures may encourage direct systems at the expense of storage systems.

  14. Alternatives for metal hydride storage bed heating and cooling

    International Nuclear Information System (INIS)

    Fisher, I.A.; Ramirez, F.B.; Koonce, J.E.; Ward, D.E.; Heung, L.K.; Weimer, M.; Berkebile, W.; French, S.T.

    1991-01-01

    The reaction of hydrogen isotopes with the storage bed hydride material is exothermic during absorption and endothermic during desorption. Therefore, storage bed operation requires a cooling system to remove heat during absorption, and a heating system to add the heat needed for desorption. Three storage bed designs and their associated methods of heating and cooling and accountability are presented within. The first design is the current RTF (Replacement Tritium Facility) nitrogen heating and cooling system. The second design uses natural convection cooling with ambient glove box nitrogen and electrical resistance for heating. This design is referred to as the Naturally Cooled/Electrically Heated (NCEH) design. The third design uses forced convection cooling with ambient glove box nitrogen and electrical resistance for heating. The design is referred to as the Forced Convection Cooled/Electrically Heated (FCCEH) design. In this report the operation, storage bed design, and equipment required for heating, cooling, and accountability of each design are described. The advantages and disadvantages of each design are listed and discussed. Based on the information presented within, it is recommended that the NCEH design be selected for further development

  15. Heat storage in forest biomass improves energy balance closure

    Science.gov (United States)

    Lindroth, A.; Mölder, M.; Lagergren, F.

    2010-01-01

    Temperature measurements in trunks and branches in a mature ca. 100 years-old mixed pine and spruce forest in central Sweden were used to estimate the heat storage in the tree biomass. The estimated heat flux in the sample trees and data on biomass distributions were used to scale up to stand level biomass heat fluxes. The rate of change of sensible and latent heat storage in the air layer below the level of the flux measurements was estimated from air temperature and humidity profile measurements and soil heat flux was estimated from heat flux plates and soil temperature measurements. The fluxes of sensible and latent heat from the forest were measured with an eddy covariance system in a tower. The analysis was made for a two-month period in summer of 1995. The tree biomass heat flux was the largest of the estimated storage components and varied between 40 and -35 W m-2 on summer days with nice weather. Averaged over two months the diurnal maximum of total heat storage was 45 W m-2 and the minimum was -35 W m-2. The soil heat flux and the sensible heat storage in air were out of phase with the biomass flux and they reached maximum values that were about 75% of the maximum of the tree biomass heat storage. The energy balance closure improved significantly when the total heat storage was added to the turbulent fluxes. The slope of a regression line with sum of fluxes and storage as independent and net radiation as dependent variable, increased from 0.86 to 0.95 for half-hourly data and the scatter was also reduced. The most significant finding was, however, that during nights with strongly stable conditions when the sensible heat flux dropped to nearly zero, the total storage matched the net radiation very well. Another interesting result was that the mean energy imbalance started to increase when the Richardson number became more negative than ca. -0.1. In fact, the largest energy deficit occurred at maximum instability. Our conclusion is that eddy covariance

  16. A control model for district heating networks with storage

    NARCIS (Netherlands)

    Scholten, Tjeert; De Persis, Claudio; Tesi, Pietro

    2014-01-01

    In [1] pressure control of hydraulic networks is investigated. We extend this work to district heating systems with storage capabilities and derive a model taking the topology of the network into account. The goal for the derived model is that it should allow for control of the storage level and

  17. Iowa state heating oil and propane program: 1996--1997 winter heating season. Final report

    International Nuclear Information System (INIS)

    1997-05-01

    The objective of the Iowa State Heating Oil and Propane Program is to develop a state-level, company-specific data collection effort so that retail price information on fuel oil and propane is collected by the staff of the Iowa Department of Natural Resources during the winter heating season. The second objective is to provide specific volume and retail price information to the US Department of Energy's (DOE's) Energy Information Administration on No. 2 heating oil and propane on a semi-monthly basis. This report summarizes the results of the residential No. 2 distillate fuel (home heating oil) and liquefied petroleum gas (propane) price survey over the 1996--1997 winter heating season in Iowa. The Iowa Department of Natural Resources conducted the survey under a cooperative financial assistance grant with the DOE Energy Information Administration (EIA)

  18. Heat transfer efficient thermal energy storage for steam generation

    International Nuclear Information System (INIS)

    Adinberg, R.; Zvegilsky, D.; Epstein, M.

    2010-01-01

    A novel reflux heat transfer storage (RHTS) concept for producing high-temperature superheated steam in the temperature range 350-400 deg. C was developed and tested. The thermal storage medium is a metallic substance, Zinc-Tin alloy, which serves as the phase change material (PCM). A high-temperature heat transfer fluid (HTF) is added to the storage medium in order to enhance heat exchange within the storage system, which comprises PCM units and the associated heat exchangers serving for charging and discharging the storage. The applied heat transfer mechanism is based on the HTF reflux created by a combined evaporation-condensation process. It was shown that a PCM with a fraction of 70 wt.% Zn in the alloy (Zn70Sn30) is optimal to attain a storage temperature of 370 deg. C, provided the heat source such as solar-produced steam or solar-heated synthetic oil has a temperature of about 400 deg. C (typical for the parabolic troughs technology). This PCM melts gradually between temperatures 200 and 370 deg. C preserving the latent heat of fusion, mainly of the Zn-component, that later, at the stage of heat discharge, will be available for producing steam. The thermal storage concept was experimentally studied using a lab scale apparatus that enabled investigating of storage materials (the PCM-HTF system) simultaneously with carrying out thermal performance measurements and observing heat transfer effects occurring in the system. The tests produced satisfactory results in terms of thermal stability and compatibility of the utilized storage materials, alloy Zn70Sn30 and the eutectic mixture of biphenyl and diphenyl oxide, up to a working temperature of 400 deg. C. Optional schemes for integrating the developed thermal storage into a solar thermal electric plant are discussed and evaluated considering a pilot scale solar plant with thermal power output of 12 MW. The storage should enable uninterrupted operation of solar thermal electric systems during additional hours

  19. Solar Air Heaters with Thermal Heat Storages

    OpenAIRE

    Saxena, Abhishek; Goel, Varun

    2013-01-01

    Solar energy can be converted into different forms of energy, either to thermal energy or to electrical energy. Solar energy is converted directly into electrical power by photovoltaic modules, while solar collector converts solar energy into thermal energy. Solar collector works by absorbing the direct solar radiation and converting it into thermal energy, which can be stored in the form of sensible heat or latent heat or a combination of sensible and latent heats. A theoretical study has be...

  20. Impact of Seasonal Heat Accumulation on Operation of Geothermal Heat Pump System with Vertical Ground Heat Exchanger

    Science.gov (United States)

    Timofeev, D. V.; Malyavina, E. G.

    2017-11-01

    The subject of the investigation was to find out the influence of heat pump operation in summer on its function in winter. For this purpose a mathematical model of a ground coupled heat pump system has been developed and programmed. The mathematical model of a system ground heat exchanger uses the finite difference method to describe the heat transfer in soil and the analytical method to specify the heat transfer in the U-tubes heat exchanger. The thermal diffusivity by the heat transfer in the soil changes during gradual freezing of the pore moisture and thus slows soil freezing. The mathematical model of a heat pump includes the description of a scroll compressor and the simplified descriptions of the evaporator and condenser. The analysis showed that heating during the cold season and cooling in the warm season affect the average heat transfer medium temperature in the soil loop in the winter season. It has been also showed that the degree of this effect depends on the clay content in the soil.

  1. Microencapsulated Phase-Change Materials For Storage Of Heat

    Science.gov (United States)

    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.

  2. Changes in the timing, length and heating degree days of the heating season in central heating zone of China

    Science.gov (United States)

    Shen, Xiangjin; Liu, Binhui

    2016-01-01

    Climate change affects the demand for energy consumption, especially for heating and cooling buildings. Using daily mean temperature (Tmean) data, this study analyzed the spatiotemporal changes of the starting date for heating (HS), ending date for heating (HE), length (HL) and heating degree day (HDD) of the heating season in central heating zone of China. Over China’s central heating zone, regional average HS has become later by 0.97 day per decade and HE has become earlier by 1.49 days per decade during 1960–2011, resulting in a decline of HL (−2.47 days/decade). Regional averaged HDD decreased significantly by 63.22 °C/decade, which implies a decreasing energy demand for heating over the central heating zone of China. Spatially, there are generally larger energy-saving rate in the south, due to low average HDD during the heating season. Over China’s central heating zone, Tmean had a greater effect on HL in warm localities and a greater effect on HDD in cold localities. We project that the sensitivity of HL (HDD) to temperature change will increase (decrease) in a warmer climate. These opposite sensitivities should be considered when we want to predict the effects of climate change on heating energy consumption in China in the future. PMID:27651063

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

    Science.gov (United States)

    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.

  4. Aquifer thermal energy storage reference manual: seasonal thermal energy storage program

    Energy Technology Data Exchange (ETDEWEB)

    Prater, L.S.

    1980-01-01

    This is the reference manual of the Seasonal Thermal Energy Storage (STES) Program, and is the primary document for the transfer of technical information of the STES Program. It has been issued in preliminary form and will be updated periodically to include more technical data and results of research. As the program progresses and new technical data become available, sections of the manual will be revised to incorporate these data. This primary document contains summaries of: the TRW, incorporated demonstration project at Behtel, Alaska, Dames and Moore demonstration project at Stony Brook, New York, and the University of Minnesota demonstration project at Minneapolis-St. Paul, Minnesota; the technical support programs including legal/institutional assessment; economic assessment; environmental assessment; field test facilities; a compendia of existing information; numerical simulation; and non-aquifer STES concepts. (LCL)

  5. Thermal performance evaluation of a latent heat storage unit for late evening cooking in a solar cooker having three reflectors

    Energy Technology Data Exchange (ETDEWEB)

    Buddhi, D.; Sharma, A. [Devi Ahilya University, Indore (India). School of Energy and Environmental Studies, Thermal Energy Storage Laboratory; Sharma, S.D. [Mie University, Tsu (Japan). Faculty of Engineering, Department of Architecture

    2003-04-01

    In this paper, a phase change material (PCM) storage unit for a solar cooker was designed and developed to store energy during sunshine hours. The stored energy was utilised to cook food in the late evening. Commercial grade acetanilide (melting point 118.9 {sup o}C, latent heat of fusion 222 kJ/kg) was used as a latent heat storage material. Evening cooking experiments were conducted with different loads and loading times during the winter season. The experimental results showed that late evening cooking is possible in a solar cooker having three reflectors to enhance the incident solar radiation with the PCM storage unit. (author)

  6. Process for adapting a heat source and a thermal machine by temporary heat storage

    International Nuclear Information System (INIS)

    Cahn, R.P.; Nicholson, E.W.

    1975-01-01

    The process described is intended to ensure the efficient use of the heat from a nuclear reactor or from a furnace burning fossil fuel at constant power, and of a boiler in a power station comprising a multi-stage steam turbine, the steam extracted from the turbine being used for pre-heating the boiler feed water. This process is most flexible with a varying load. It includes the high temperature storage of the excess heat energy in a low vapor pressure storage liquid (hydrocarbon oils, molten salts or liquid metals) at atmospheric pressure when the demand is low; then, when the energy demand is at its height, the reduction of steam extraction from the turbine with simultaneous utilisation of the hot heat storage liquid for the various maintenance heating functions of the power station by heat exchange, so that the heat can expand totally in the turbine with generation of energy [fr

  7. Demand for seasonal gas storage in northwest Europe until 2030. Simulation results with a dynamic model

    International Nuclear Information System (INIS)

    De Joode, J.; Oezdemir, Oe.

    2010-01-01

    The fact that depletion of indigenous gas production increases gas import dependency is widely known and accepted. However, there is considerable less attention for the implications of indigenous resource depletion for the provision of seasonal flexibility. The traditionally largest source of seasonal flexibility in Europe is indigenous gas production, mainly based in the Netherlands and the United Kingdom. With the depletion of indigenous sources the market increasingly needs to rely on other sources for seasonal flexibility, such as gas storage facilities. We investigate the future need for gas storage as a source for seasonal flexibility provision using a dynamic gas market model (GASTALE) in which different potential sources for seasonal flexibility - gas production, imports via pipeline, LNG imports and storage facilities - compete with each other in a market-based environment. The inclusion of seasonal flexibility properties in a gas market model allows a more complex analysis of seasonal flexibility issues than previously documented in literature. This is demonstrated in an analysis of the future demand for gas storage in northwestern Europe until 2030. Our results indicate that there is substantial need for additional gas storage facilities and thus supports current project proposals for new investment in gas storage facilities. (author)

  8. Climate model biases in seasonality of continental water storage revealed by satellite gravimetry

    Science.gov (United States)

    Swenson, Sean; Milly, P.C.D.

    2006-01-01

    Satellite gravimetric observations of monthly changes in continental water storage are compared with outputs from five climate models. All models qualitatively reproduce the global pattern of annual storage amplitude, and the seasonal cycle of global average storage is reproduced well, consistent with earlier studies. However, global average agreements mask systematic model biases in low latitudes. Seasonal extrema of low‐latitude, hemispheric storage generally occur too early in the models, and model‐specific errors in amplitude of the low‐latitude annual variations are substantial. These errors are potentially explicable in terms of neglected or suboptimally parameterized water stores in the land models and precipitation biases in the climate models.

  9. Efficient numerical simulation of heat storage in subsurface georeservoirs

    Science.gov (United States)

    Boockmeyer, A.; Bauer, S.

    2015-12-01

    The transition of the German energy market towards renewable energy sources, e.g. wind or solar power, requires energy storage technologies to compensate for their fluctuating production. Large amounts of energy could be stored in georeservoirs such as porous formations in the subsurface. One possibility here is to store heat with high temperatures of up to 90°C through borehole heat exchangers (BHEs) since more than 80 % of the total energy consumption in German households are used for heating and hot water supply. Within the ANGUS+ project potential environmental impacts of such heat storages are assessed and quantified. Numerical simulations are performed to predict storage capacities, storage cycle times, and induced effects. For simulation of these highly dynamic storage sites, detailed high-resolution models are required. We set up a model that accounts for all components of the BHE and verified it using experimental data. The model ensures accurate simulation results but also leads to large numerical meshes and thus high simulation times. In this work, we therefore present a numerical model for each type of BHE (single U, double U and coaxial) that reduces the number of elements and the simulation time significantly for use in larger scale simulations. The numerical model includes all BHE components and represents the temporal and spatial temperature distribution with an accuracy of less than 2% deviation from the fully discretized model. By changing the BHE geometry and using equivalent parameters, the simulation time is reduced by a factor of ~10 for single U-tube BHEs, ~20 for double U-tube BHEs and ~150 for coaxial BHEs. Results of a sensitivity study that quantify the effects of different design and storage formation parameters on temperature distribution and storage efficiency for heat storage using multiple BHEs are then shown. It is found that storage efficiency strongly depends on the number of BHEs composing the storage site, their distance and

  10. Magnetic properties of atmospheric PMx in a small settlement during heating and non-heating season

    Science.gov (United States)

    Petrovsky, E.; Kotlik, B.; Zboril, R.; Kapicka, A.; Grison, H.

    2012-04-01

    Magnetic properties of environmental samples can serve as fast and relatively cheap proxy method to investigate occurrence of iron oxides. These methods are very sensitive in detecting strongly magnetic compounds such as magnetite and maghemite and can reveal concentration and assess grain-size distribution of these minerals. This information can be significant in estimating e.g. the source of pollutants, monitoring pollution load, or investigating seasonal and climatic effects. We studied magnetic properties of PM1, PM2.5 and PM10, collected over 32-48 hours in a small settlement in south Bohemia during heating and non-heating season. The site is rather remote, with negligible traffic and industrial contributions to air pollution. Thus, the suggested seasonal effect should be dominantly due to local (domestic) heating, burning wood or coal. In our contribution we show typical differences in PMx concentration, which is much higher in the winter (heating) sample, accompanied by SEM analyses and magnetic data oriented on concentration and grain-size distribution of magnetite/maghemite particles. While concentration of Fe-oxides does not vary that much, significant seasonal differences were observed in composition and grain-size distribution, reflecting different sources of the dust particles.

  11. Seasonal Thermal-Energy Storage: A Critical Review on BTES Systems, Modeling, and System Design for Higher System Efficiency

    Directory of Open Access Journals (Sweden)

    Michael Lanahan

    2017-05-01

    Full Text Available Buildings consume approximately ¾ of the total electricity generated in the United States, contributing significantly to fossil fuel emissions. Sustainable and renewable energy production can reduce fossil fuel use, but necessitates storage for energy reliability in order to compensate for the intermittency of renewable energy generation. Energy storage is critical for success in developing a sustainable energy grid because it facilitates higher renewable energy penetration by mitigating the gap between energy generation and demand. This review analyzes recent case studies—numerical and field experiments—seen by borehole thermal energy storage (BTES in space heating and domestic hot water capacities, coupled with solar thermal energy. System design, model development, and working principle(s are the primary focus of this analysis. A synopsis of the current efforts to effectively model BTES is presented as well. The literature review reveals that: (1 energy storage is most effective when diurnal and seasonal storage are used in conjunction; (2 no established link exists between BTES computational fluid dynamics (CFD models integrated with whole building energy analysis tools, rather than parameter-fit component models; (3 BTES has less geographical limitations than Aquifer Thermal Energy Storage (ATES and lower installation cost scale than hot water tanks and (4 BTES is more often used for heating than for cooling applications.

  12. Testing of PCM Heat Storage Modules with Solar Collectors as Heat Source

    DEFF Research Database (Denmark)

    Englmair, Gerald; Dannemand, Mark; Johansen, Jakob Berg

    2016-01-01

    A latent heat storage based on the phase change material Sodium Acetate Trihydrate (SAT) has been tested as part of a demonstration system. The full heat storage consisted of 4 individual modules each containing about 200 kg of sodium acetate trihydrate with different additives. The aim...... was to actively utilize the ability of the material to supercool to obtain long storage periods. The modules were charged with solar heat supplied by 22.4 m2 evacuated tubular collectors. The investigation showed that it was possible to fully charge one module within a period of 270 minutes with clear skies...

  13. Lab-scale experiment of a closed thermochemical heat storage system including honeycomb heat exchanger

    International Nuclear Information System (INIS)

    Fopah-Lele, Armand; Rohde, Christian; Neumann, Karsten; Tietjen, Theo; Rönnebeck, Thomas; N'Tsoukpoe, Kokouvi Edem; Osterland, Thomas; Opel, Oliver

    2016-01-01

    A lab-scale thermochemical heat storage reactor was developed in the European project “thermal battery” to obtain information on the characteristics of a closed heat storage system, based on thermochemical reactions. The present type of storage is capable of re-using waste heat from cogeneration system to produce useful heat for space heating. The storage material used was SrBr 2 ·6H 2 O. Due to agglomeration or gel-like problems, a structural element was introduced to enhance vapour and heat transfer. Honeycomb heat exchanger was designed and tested. 13 dehydration-hydration cycles were studied under low-temperature conditions (material temperatures < 100 °C) for storage. Discharging was realized at water vapour pressure of about 42 mbar. Temperature evolution inside the reactor at different times and positions, chemical conversion, thermal power and overall efficiency were analysed for the selected cycles. Experimental system thermal capacity and efficiency of 65 kWh and 0.77 are respectively obtained with about 1 kg of SrBr 2 ·6H 2 O. Heat transfer fluid recovers heat at a short span of about 43 °C with an average of 22 °C during about 4 h, acceptable temperature for the human comfort (20 °C on day and 16 °C at night). System performances were obtained for a salt bed energy density of 213 kWh·m 3 . The overall heat transfer coefficient of the honeycomb heat exchanger has an average value of 147 W m −2  K −1 . Though promising results have been obtained, ameliorations need to be made, in order to make the closed thermochemical heat storage system competitive for space heating. - Highlights: • Lab-scale thermochemical heat storage is designed, constructed and tested. • The use of honeycomb heat exchanger as a heat and vapour process enhancement. • Closed system (1 kg SrBr 2 ·6H 2 O) able to give back 3/4 of initial thermal waste energy. • System storage capacity and thermal efficiency are respectively 65 kWh and 0.77.

  14. Improved performance of heat pumps helps to use full potential of subsurface space for Aquifer Thermal Energy Storage

    NARCIS (Netherlands)

    Bloemendal, J.M.; Jaxa-Rozen, M.; Rostampour Samarin, Vahab

    2017-01-01

    The application of seasonal Aquifer Thermal Energy Storage (ATES) contributes to meet goals for energy savings and greenhouse gas (GHG) emission reductions. Heat pumps have a crucial position in ATES systems because they dictate the operation scheme of the ATES wells and therefore play an important

  15. A DFT based equilibrium study of a chemical mixture Tachyhydrite and their lower hydrates for long term heat storage

    NARCIS (Netherlands)

    Pathak, A.D.; Gaastra - Nedea, S.V.; Zondag, H.A.; Rindt, C.C.M.; Smeulders, D.M.J.

    2016-01-01

    Chloride based salt hydrates are promising materials for seasonal heat storage. However, hydrolysis, a side reaction, deteriorates, their cycle stability. To improve the kinetics and durability, we have investigated the optimum operating conditions of a chemical mixture of CaCl2 and MgCl2 hydrates.

  16. Hydration of Magnesium Carbonate in a Thermal Energy Storage Process and Its Heating Application Design

    Directory of Open Access Journals (Sweden)

    Rickard Erlund

    2018-01-01

    Full Text Available First ideas of applications design using magnesium (hydro carbonates mixed with silica gel for day/night and seasonal thermal energy storage are presented. The application implies using solar (or another heat source for heating up the thermal energy storage (dehydration unit during daytime or summertime, of which energy can be discharged (hydration during night-time or winter. The applications can be used in small houses or bigger buildings. Experimental data are presented, determining and analysing kinetics and operating temperatures for the applications. In this paper the focus is on the hydration part of the process, which is the more challenging part, considering conversion and kinetics. Various operating temperatures for both the reactor and the water (storage tank are tested and the favourable temperatures are presented and discussed. Applications both using ground heat for water vapour generation and using water vapour from indoor air are presented. The thermal energy storage system with mixed nesquehonite (NQ and silica gel (SG can use both low (25–50% and high (75% relative humidity (RH air for hydration. The hydration at 40% RH gives a thermal storage capacity of 0.32 MJ/kg while 75% RH gives a capacity of 0.68 MJ/kg.

  17. High-temperature acquifer thermal storage and underground heat storage; IEA ECES Annex 12: Hochtemperatur-Erdwaermesonden- und Aquiferwaermespeicher

    Energy Technology Data Exchange (ETDEWEB)

    Sanner, B.; Knoblich, K. [Giessen Univ. (Germany). Inst. fuer Angewandte Geowissenschaften; Koch, M.; Adinolfi, M. [Stuttgart Univ. (Germany). Inst. fuer Siedlungswasserbau, Wasserguete und Abfallwirtschaft

    1998-12-31

    Heat storage is essential for the reconciliation of heat supply and demand. The earth has already proved to be an excellent medium for storing large amounts of heat over longer periods of time, for instance during the cold and hot season. The efficiency of the storage is the better the lower storage losses are at high temperature levels. Unfortunately this can not be easily achieved. While thermal underground stores, which are widely used for cold storage, have proved to perform quite well at temperatures between 10 C - 40 C, it has been rather difficult to achieve similar results at higher temperatures up to 150 C as test and demonstration plants of the 1980s proved. This issue has again attracted so much interest that the IEA launched a project on high temperature underground storage in December 1998. (orig.) [Deutsch] Waermespeicherung ist von entscheidender Bedeutung, wenn es darum geht, ein Waermeangebot mit einer Waermenachfrage zeitlich zur Deckung zu bringen. Der Untergrund hat sich schon seit vielen Jahren als ein geeignetes Medium erwiesen, groessere Waermepumpen ueber laengere Zeitraeume wie etwa die kalten und warmen Jahreszeiten zu speichern. Die Effizienz eines solchen Speichers steigt mit der Hoehe des erreichten Temperaturniveaus und mit sinkenden Speicherverlusten, was leider eher gegenlaeufige Erscheinungen sind. Waehrend thermische Untergrundspeicher im Temperaturbereich von 10-40 C inzwischen erfolgreich demonstriert wurden und vor allem zur Kaeltespeicherung auch bereits vielfach eingesetzt werden, haben hoehere Temperaturen bis etwa 150 C in den Versuchs- und Demonstrationsanlagen der 80er Jahre vielfaeltige Probleme bereitet. Im Gefolge eines erneuten Interesses an unterirdischer thermischer Energiespeicherung wurde im Dezember 1997 ein Vorhaben des IEA Energiespeicherprogramms zu Untergrund-Waermespeichern hoeherer Temperatur eingerichtet. (orig.)

  18. Economics of long-distance transmission, storage, and distribution of heat from nuclear plants with existing and newer techniques

    International Nuclear Information System (INIS)

    Margen, P.H.

    1978-01-01

    Conventional and newer types of hot-water pipes are applied to the bulk transport of reject heat from central nuclear power plants to the district heating network of cities or groups of cities. With conventional pipes, the transport of 300 to 2000 MW of heat over distances of 30 to 100 km can be justified, while with newer pipe types, even longer distances would often be economic. For medium-size district heating schemes, low-temperature heat transport from simple heat-only reactors suitable for closer location to cities is of interest. For daily storage of heat on district heating systems, steel heat accumulators are currently used in Sweden. The development of more advanced cheaper heat accumulators, such as lake storage schemes, could make even seasonal heat storage economic. Newer distribution technology extends the economic field of penetration of district heating even to suburban one-family house districts. With proper design and optimization, nuclear district heating can be competitive in a wide market and achieve very substantial fossil-fuel savings

  19. HYBRID INDIRECT SOLAR COOKER WITH LATENT HEAT STORAGE

    OpenAIRE

    Benazeer Hassan K. Ibrahim *, Victor Jose

    2016-01-01

    Solar cooking is the simplest, safest, most convenient way to cook food without consuming fuels or heating up the kitchen. All the conventional solar cooker designs have the disadvantage of inability to cook during off-shine and night hours.This disadvantage can be eliminated if the solar cooker is designed with thermal storage arrangement. In this paper, a hybrid solar cooker with evacuated tube collector and latent thermal storage unit and alternate electric heatingsource is simulated. The...

  20. District heating system Neckarsulm-Amorbach. Demonstration plant - seasonal thermal energy storage Amorbach II - experience report on construction and operation; Nahwaermeversorgung Neckarsulm-Amorbach. Demonstrationsanlage Saisonaler Erdwaermespeicher Amorbach II - Erfahrungen bei Bau und Betrieb

    Energy Technology Data Exchange (ETDEWEB)

    Effenberger, S. [Stadtwerke Neckarsulm (Germany)

    1998-12-31

    By an exchange the city of Neckarsulm acquired fifty hectare of a building site from the neighbouring community Oedheim in the east of the district Amorbach in 1992. The initial intention was to supply the whole area with natural gas but during the construction phase the decision was taken to build a district heating system parallel to the `Bordighera Allee`, fortunately it was taken in time and did not incur additional costs. Supported by two cogeneration plants with a thermal capacity of 50 kW each 250 units in residential buildings are supposed to be supplied. Another system has been set up between Eugen-Bolz Strasse and Oedheimer Strasse in order to supply 250 units in terrace houses, semi detached houses and residential buildings. This district heating system has been designed in such a way that approximately 12% of the yearly energy demand is met by the collector plant with an area of 700 square metres and the residual energy is generated by two gas fuelled high-efficiency boilers with a capacity of 1.44 MW. The solar energy as well as the energy generated by the boilers are stored parallel in a buffer tank with a capacity of 20 cubic metres that has been set up next to the heating plant in a separate basement room. (orig.) [Deutsch] Im Jahre 1992 hat die Stadt Neckarsulm ueber einen Markungstausch 50 Hektar Bauland oestlich des Stadtteiles Amorbach von der Nachbargemeinde Oedheim erworben. Entgegen der urspruenglichen Absicht, das ganze Gebiet konventionell mit Erdgas zu versorgen, wurde noch in der Bauphase, jedoch rechtzeitig ohne Mehrkosten zu produzieren, beschlossen in einem Teilbereich entlang der Bordighera-Allee eine Nahwaermeinsel aufzubauen. Mit Unterstuetzung von zwei BHKW-Aggregaten mit einer thermischen Leistung von jeweils 50 KW sollten 250 Wohneinheiten vorwiegend im Geschosswohnbau versorgt werden. Fast parallel zu dieser Insel entstand ein weiteres Projekt zwischen der Eugen-Bolz-Strasse und der Oedheimer Strasse zur Versorgung von weiteren

  1. Heat pipe solar receiver with thermal energy storage

    Science.gov (United States)

    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.

  2. Investigation of a heat storage for a solar heating system for combined space heating and domestic hot water supply for homeowner´s association "Bakken"

    DEFF Research Database (Denmark)

    Vejen, Niels Kristian

    1998-01-01

    A heat storage for a solar heating system for combined space heating and domestic hot water supply was tested in a laboratory test facility.The heat storage consist of a mantle tank with water for the heating system and of a hot water tank, which by means of thermosyphoning is heated by the water...

  3. Numerical Analysis of Heat Storage and Heat Conductivity in the Concrete Hollow Core Deck Element

    DEFF Research Database (Denmark)

    Pomianowski, Michal Zbigniew; Heiselberg, Per; Jensen, Rasmus Lund

    2011-01-01

    extent these simplified models estimate the heat storage potential of precast hollow-core concrete decks correctly. This study investigates various approaches on how to model the heat transfer within the air void in the deck. Furthermore, it is analysed how different heat transfer models influence...... the overall heat transfer and heat storage in the hollow-core decks. The presented results allow comparison between detailed results from 2D-COMSOL simulations and simple 1D calculations from the whole building simulation tool such as BSim program and moreover, it is possible to validate the calculation...... method in BSim for the concrete deck element with air voids. Finally, this paper presents a comparison of the calculated heat conductivity of the hollow-core concrete deck and the measured heat conductivity for the same deck by using hot box apparatus....

  4. Combined Heat and Power Dispatch Considering Heat Storage of Both Buildings and Pipelines in District Heating System for Wind Power Integration

    Directory of Open Access Journals (Sweden)

    Ping Li

    2017-06-01

    Full Text Available The strong coupling between electric power and heat supply highly restricts the electric power generation range of combined heat and power (CHP units during heating seasons. This makes the system operational flexibility very low, which leads to heavy wind power curtailment, especially in the region with a high percentage of CHP units and abundant wind power energy such as northeastern China. The heat storage capacity of pipelines and buildings of the district heating system (DHS, which already exist in the urban infrastructures, can be exploited to realize the power and heat decoupling without any additional investment. We formulate a combined heat and power dispatch model considering both the pipelines’ dynamic thermal performance (PDTP and the buildings’ thermal inertia (BTI, abbreviated as the CPB-CHPD model, emphasizing the coordinating operation between the electric power and district heating systems to break the strong coupling without impacting end users’ heat supply quality. Simulation results demonstrate that the proposed CPB-CHPD model has much better synergic benefits than the model considering only PDTP or BTI on wind power integration and total operation cost savings.

  5. Advances in Large-Scale Solar Heating and Long Term Storage in Denmark

    DEFF Research Database (Denmark)

    Heller, Alfred

    2000-01-01

    According to (the) information from the European Large-Scale Solar Heating Network, (See http://www.hvac.chalmers.se/cshp/), the area of installed solar collectors for large-scale application is in Europe, approximately 8 mill m2, corresponding to about 4000 MW thermal power. The 11 plants...... the last 10 years and the corresponding cost per collector area for the final installed plant is kept constant, even so the solar production is increased. Unfortunately large-scale seasonal storage was not able to keep up with the advances in solar technology, at least for pit water and gravel storage...... of the total 51 plants are equipped with long-term storage. In Denmark, 7 plants are installed, comprising of approx. 18,000-m2 collector area with new plants planned. The development of these plants and the involved technologies will be presented in this paper, with a focus on the improvements for Danish...

  6. Day-to-night heat storage in greenhouses

    NARCIS (Netherlands)

    Seginer, Ido; Straten, van Gerrit; Beveren, van Peter J.M.

    2017-01-01

    Day-to-night heat storage in water tanks (buffers) is common practice in cold-climate greenhouses, where gas is burned during the day for carbon dioxide enrichment. In Part 1 of this study, an optimal control approach was outlined for such a system, the basic idea being that the virtual value

  7. Building with integral solar-heat storage--Starkville, Mississippi

    Science.gov (United States)

    1981-01-01

    Column supporting roof also houses rock-storage bin of solar-energy system supplying more than half building space heating load. Conventional heaters supply hot water. Since bin is deeper and narrower than normal, individual pebble size was increased to keep airflow resistance at minimum.

  8. Rock bed storage with heat pump. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Remmers, H.E.; Mills, G.L.

    1979-05-01

    The study, Rock Bed Storage with Heat Pump, established the feasibility of mating a heat pump to a rock bed storage to effect optimal performance at the lowest cost in single family residences. The operating characteristics of off-the-shelf components of heat pump/rock bed storage systems were studied, and the results were used to formulate configurations of representative systems. These systems were modeled and subsequently analyzed using the TRNSYS computer program and a life cycle cost analysis program called LCCA. A detailed load model of a baseline house was formulated as part of the TRNSYS analysis. Results of the analysis involved the development of a technique to confine the range of heat pump/rock bed storage systems to those systems which are economical for a specific location and set of economic conditions. Additionally, the results included a comparison of the detailed load model with simple UA models such as the ASHRAE bin method. Several modifications and additions were made to the TRNSYS and LCCA computer programs during the course of the study.

  9. An experimental investigation of shell and tube latent heat storage for solar dryer using paraffin wax as heat storage material

    Directory of Open Access Journals (Sweden)

    Ashish Agarwal

    2016-03-01

    Full Text Available In the presented study the shell and tube type latent heat storage (LHS has been designed for solar dryer and paraffin wax is used as heat storage material. In the first part of the study, the thermal and heat transfer characteristics of the latent heat storage system have been evaluated during charging and discharging process using air as heat transfer fluid (HTF. In the last section of the study the effectiveness of the use of an LHS for drying of food product and also on the drying kinetics of a food product has been determined. A series of experiments were conducted to study the effects of flow rate and temperature of HTF on the charging and discharging process of LHS. The temperature distribution along the radial and longitudinal directions was obtained at different time during charging process to analyze the heat transfer phenomenon in the LHS. Thermal performance of the system is evaluated in terms of cumulative energy charged and discharged, during the charging and discharging process of LHS, respectively. Experimental results show that the LHS is suitable to supply the hot air for drying of food product during non-sunshine hours or when the intensity of solar energy is very low. Temperature gain of air in the range of 17 °C to 5 °C for approximately 10 hrs duration was achieved during discharging of LHS.

  10. Experimental results of a 3 k Wh thermochemical heat storage module for space heating application

    NARCIS (Netherlands)

    Finck, C.J.; Henquet, E.M.R.; Soest, C.F.L. van; Oversloot, H.P.; Jong, A.J. de; Cuypers, R.; Spijker, J.C. van 't

    2014-01-01

    A 3 kWh thermochemical heat storage (TCS) module was built as part of an all-in house system implementation focusing on space heating application at a temperature level of 40 ºC and a temperature lift of 20 K. It has been tested and measurements showed a maximum water circuit temperature span

  11. Nanoscale heat transfer in carbon nanotube - sugar alcohol composites as heat storage materials

    NARCIS (Netherlands)

    Zhang, H.; Rindt, C.C.M.; Smeulders, D.M.J.; Gaastra - Nedea, S.V.

    2016-01-01

    Nanoscale carbon structures such as graphene and carbon nanotubes (CNTs) can greatly improve the effective thermal conductivity of thermally sluggish heat storage materials, such as sugar alcohols (SAs). The specific improvement depends on the heat transfer rate across the carbon structure. Besides,

  12. Winter electricity supply and seasonal storage deficit in the Swiss Alps

    Science.gov (United States)

    Manso, Pedro; Monay, Blaise; Dujardin, Jérôme; Schaefli, Bettina; Schleiss, Anton

    2017-04-01

    Switzerland electricity production depends at 60% on hydropower, most of the remainder coming from nuclear power plants. The ongoing energy transition foresees an increase in renewable electricity production of solar photovoltaic, wind and geothermal origin to replace part of nuclear production; hydropower, in its several forms, will continue to provide the backbone and the guarantee of the instantaneous and permanent stability of the electric system. One of the key elements of any future portfolio of electricity mix with higher shares of intermittent energy sources like wind and solar are fast energy storage and energy deployment solutions. Hydropower schemes with pumping capabilities are eligible for storage at different time scales, whereas high-head storage hydropower schemes have already a cornerstone role in today's grid operation. These hydropower storage schemes have also been doing what can be labelled as "seasonal energy storage" in different extents, storing abundant flows in the wet season (summer) to produce electricity in the dry (winter) alpine season. Some of the existing reservoirs are however under sized with regards to the available water inflows and either spill over or operate as "run-of-the-river" which is economically suboptimal. Their role in seasonal energy transfer could increase through storage capacity increase (by dam heightening, by new storage dams in the same catchment). Inversely, other reservoirs that already store most of the wet season inflow might not fill up in the future in case inflows decrease due to climate changes; these reservoirs might then have extra storage capacity available to store energy from sources like solar and wind, if water pumping capacity is added or increased. The present work presents a comprehensive methodology for the identification of the seasonal storage deficit per catchment considering todays and future hydrological conditions with climate change, applied to several landmark case studies in

  13. Liquid neon heat intercept for superconducting energy storage magnets

    International Nuclear Information System (INIS)

    Khalil, A.; McIntosh, G.E.

    1982-01-01

    Previous analyses of heat intercept solutions are extended to include both insulation and strut heat leaks. The impact of using storable, boiling cryogens for heat intercept fluids, specifically liquid neon and nitrogen, is also examined. The selection of fluid for the heat intercepts is described. Refrigeration power for 1000 and 5000 MWhr SMES units is shown with optimum refrigeration power for each quantity shown in tables. Nitrogen and Neon cooled intercept location for minimum total refrigeration power for a 5000 MWhr SMES are each shown, as well as the location of nitrogen and neon cooled intercepts for minimum total refrigeration power for 5000 MWhr SMES. Cost comparisons are itemized and neon cost and availability discussed. For a large energy storage magnet system, liquid neon is a more effective heat intercept fluid than liquid nitrogen. Reasons and application of the conclusion are amplified

  14. Wind power integration with heat pumps, heat storages, and electric vehicles - Energy systems analysis and modelling

    Energy Technology Data Exchange (ETDEWEB)

    Hedegaard, K.

    2013-09-15

    This PhD investigates to which extent heat pumps, heat storages, and electric vehicles can support the integration of wind power. Considering the gaps in existing research, the main focus is put on individual heat pumps in the residential sector (one-family houses) and the possibilities for flexible operation, using the heat storage options available. Several energy systems analyses are performed using the energy system models, Balmorel, developed at the former TSO, ElkraftSystem, and, EnergyPLAN, developed at Aalborg University. The Danish energy system towards 2030, with wind power penetrations of up to 60 %, is used as a case study in most of the analyses. Both models have been developed further, resulting in an improved representation of individual heat pumps and heat storages. An extensive model add-on for Balmorel renders it possible to optimise investment and operation of individual heat pumps and different types of heat storages, in integration with the energy system. Total costs of the energy system are minimised in the optimisation. The add-on incorporates thermal building dynamics and covers various different heat storage options: intelligent heat storage in the building structure for houses with radiator heating and floor heating, respectively, heat accumulation tanks on the space heating circuit, as well as hot water tanks. In EnergyPLAN, some of the heat storage options have been modelled in a technical optimisation that minimises fuel consumption of the energy system and utilises as much wind power as possible. The energy systems analyses reveal that in terms of supporting wind power integration, the installation of individual heat pumps is an important step, while adding heat storages to the heat pumps is less influential. When equipping the heat pumps with heat storages, only moderate system benefits can be gained. Hereof, the main system benefit is that the need for peak/reserve capacity investments can be reduced through peak load shaving; in

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

    International Nuclear Information System (INIS)

    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 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

  16. An optimisation framework for thermal energy storage integration in a residential heat pump heating system

    International Nuclear Information System (INIS)

    Renaldi, R.; Kiprakis, A.; Friedrich, D.

    2017-01-01

    Highlights: • An integrated framework for the optimal design of low carbon heating systems. • Development of a synthetic heat demand model with occupancy profiles. • Linear model of a heat pump with thermal energy storage heating system. • Evaluation of domestic heating system from generally available input parameters. • The lower carbon heating system can be cost competitive with conventional systems. - Abstract: Domestic heating has a large share in the UK total energy consumption and significant contribution to the greenhouse gas emissions since it is mainly fulfilled by fossil fuels. Therefore, decarbonising the heating system is essential and an option to achieve this is by heating system electrification through heat pumps (HP) installation in combination with renewable power generation. A potential increase in performance and flexibility can be achieved by pairing HP with thermal energy storage (TES), which allows the shifting of heat demand to off peak periods or periods with surplus renewable electricity. We present a design and operational optimisation model which is able to assess the performance of HP–TES relative to conventional heating systems. The optimisation is performed on a synthetic heat demand model which requires only the annual heat demand, temperature and occupancy profiles. The results show that the equipment and operational cost of a HP system without TES are significantly higher than for a conventional system. However, the integration of TES and time-of-use tariffs reduce the operational cost of the HP systems and in combination with the Renewable Heating Incentive make the HP systems cost competitive with conventional systems. The presented demand model and optimisation procedure will enable the design of low carbon district heating systems which integrate the heating system with the variable renewable electricity supply.

  17. Program listing for heat-pump seasonal-performance model (SPM). [CNHSPM

    Energy Technology Data Exchange (ETDEWEB)

    1982-06-30

    The computer program CNHSPM is listed which predicts heat pump seasonal energy consumption (including defrost, cyclic degradation, and supplementary heat) using steady state rating point performance and binned weather data. (LEW)

  18. Seasonal variability of heat flux divergence in the coastal waters of Visakhapatnam

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, B.P.; Sadhuram, Y.

    Heat flux divergence (Qv) in the coastal waters of Visakhapatnam, Andhra, Pradesh, India during different seasons, was estimated for the period February 1980-January 1981. It is found that the water column (0-60 m) gains heat during winter...

  19. Comprehensive thermodynamic analysis of a renewable energy sourced hybrid heating system combined with latent heat storage

    International Nuclear Information System (INIS)

    Utlu, Zafer; Aydın, Devrim; Kıncay, Olcay

    2014-01-01

    Highlights: • An experimental thermal investigation of hybrid renewable heating system is presented. • Analyses were done by using real data obtained from a prototype structure. • Exergy efficiency of system components investigated during discharging period are close to each other as 32%. • The average input energy and exergy rates to the LHS were 0.770 and 0.027 kW. • Overall total energy and exergy efficiencies of LHS calculated as 72% and 28.4%. - Abstract: In this study an experimental thermal investigation of hybrid renewable heating system is presented. Latent heat storage stores energy, gained by solar collectors and supplies medium temperature heat to heat pump both day time also night time while solar energy is unavailable. In addition to this an accumulation tank exists in the system as sensible heat storage. It provides supply–demand balance with storing excess high temperature heat. Analyses were done according to thermodynamic’s first and second laws by using real data obtained from a prototype structure, built as part of a project. Results show that high percent of heat loses took place in heat pump with 1.83 kW where accumulator-wall heating cycle followed it with 0.42 kW. Contrarily highest break-down of exergy loses occur accumulator-wall heating cycle with 0.28 kW. Averagely 2.42 kW exergy destruction took place in whole system during the experiment. Solar collectors and heat pump are the promising components in terms of exergy destruction with 1.15 kW and 1.09 kW respectively. Exergy efficiency of system components, investigated during discharging period are in a close approximately of 32%. However, efficiency of solar collectors and charging of latent heat storage are 2.3% and 7% which are relatively low. Average overall total energy and exergy efficiencies of latent heat storage calculated as 72% and 28.4% respectively. Discharging energy efficiency of latent heat storage is the highest through all system components. Also heat

  20. Coupling Geothermal Heat Pumps with Underground Seasonal Thermal Energy Storage

    Science.gov (United States)

    2017-03-21

    Demonstration was a team effort with many contributors and “champions”, without whose support and enthusiasm the project would have stalled or even failed...BTES can be installed. Economic considerations are primarily related to the local drilling cost and type of formation (rock, sand , etc.), thermal...aquifer free from surface contaminants with an upper confining layer, generally insuring it will be anoxic. • ATES injection permits are required

  1. Development of road hydronic snow-ice melting system with solar energy and seasonal underground thermal energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Q.; Liu, Y.; Ma, C.Q.; Li, M.; Huang, Y.; Yu, M. [Jilin Univ., Changchun (China). Dept. of Thermal Energy Engineering; Liu, X.B. [Climate Master Inc., OK (United States)

    2008-07-01

    Snow and ice melting technologies that used thermal energy storage were explored. The study included analyses of solar heat slab, seasonal underground thermal energy storage, and embedded pipe technologies. Different road materials, roadbed construction methods, and underground rock and soil conditions were also discussed. New processes combining all 3 of the main technologies were also reviewed. Other thermal ice melting technologies included conductive concrete and asphalt; heating cables, and hydronic melting systems. Geothermal energy is increasingly being considered as a means of melting snow and ice from roads and other infrastructure. Researchers have also been focusing on simulating heat transfer in solar collectors and road-embedded pipes. Demonstration projects in Japan, Switzerland, and Poland are exploring the use of combined geothermal and solar energy processes to remove snow and ice from roads. Research on hydronic melting technologies is also being conducted in the United States. The study demonstrated that snow-ice melting energy storage systems will become an important and sustainable method of snow and ice removal in the future. The technology efficiently uses renewable energy sources, and provides a cost-effective means of replacing or reducing chemical melting agents. 33 refs., 1 fig.

  2. Flexibility of a combined heat and power system with thermal energy storage for district heating

    International Nuclear Information System (INIS)

    Nuytten, Thomas; Claessens, Bert; Paredis, Kristof; Van Bael, Johan; Six, Daan

    2013-01-01

    Highlights: ► A generic model for flexibility assessment of thermal systems is proposed. ► The model is applied to a combined heat and power system with thermal energy storage. ► A centrally located storage offers more flexibility compared to individual units. ► Increasing the flexibility requires both a more powerful CHP and a larger buffer. - Abstract: The trend towards an increased importance of distributed (renewable) energy resources characterized by intermittent operation redefines the energy landscape. The stochastic nature of the energy systems on the supply side requires increased flexibility at the demand side. We present a model that determines the theoretical maximum of flexibility of a combined heat and power system coupled to a thermal energy storage solution that can be either centralized or decentralized. Conventional central heating, to meet the heat demand at peak moments, is also available. The implications of both storage concepts are evaluated in a reference district. The amount of flexibility created in the district heating system is determined by the approach of the system through delayed or forced operation mode. It is found that the distinction between the implementation of the thermal energy storage as a central unit or as a collection of local units, has a dramatic effect on the amount of available flexibility

  3. Seasonal storage and alternative carriers: A flexible hydrogen supply chain model

    International Nuclear Information System (INIS)

    Reuß, M.; Grube, T.; Robinius, M.; Preuster, P.; Wasserscheid, P.; Stolten, D.

    2017-01-01

    Highlights: •Techno-economic model of future hydrogen supply chains. •Implementation of liquid organic hydrogen carriers into a hydrogen mobility analysis. •Consideration of large-scale seasonal storage for fluctuating renewable hydrogen production. •Implementation of different technologies for hydrogen storage and transportation. -- Abstract: A viable hydrogen infrastructure is one of the main challenges for fuel cells in mobile applications. Several studies have investigated the most cost-efficient hydrogen supply chain structure, with a focus on hydrogen transportation. However, supply chain models based on hydrogen produced by electrolysis require additional seasonal hydrogen storage capacity to close the gap between fluctuation in renewable generation from surplus electricity and fuelling station demand. To address this issue, we developed a model that draws on and extends approaches in the literature with respect to long-term storage. Thus, we analyse Liquid Organic Hydrogen Carriers (LOHC) and show their potential impact on future hydrogen mobility. We demonstrate that LOHC-based pathways are highly promising especially for smaller-scale hydrogen demand and if storage in salt caverns remains uncompetitive, but emit more greenhouse gases (GHG) than other gaseous or hydrogen ones. Liquid hydrogen as a seasonal storage medium offers no advantage compared to LOHC or cavern storage since lower electricity prices for flexible operation cannot balance the investment costs of liquefaction plants. A well-to-wheel analysis indicates that all investigated pathways have less than 30% GHG-emissions compared to conventional fossil fuel pathways within a European framework.

  4. Experimental Investigation of A Heat Pipe-Assisted Latent Heat Thermal Energy Storage System

    Science.gov (United States)

    Tiari, Saeed; Mahdavi, Mahboobe; Qiu, Songgang

    2016-11-01

    In the present work, different operation modes of a latent heat thermal energy storage system assisted by a heat pipe network were studied experimentally. Rubitherm RT55 enclosed by a vertical cylindrical container was used as the Phase Change Material (PCM). The embedded heat pipe network consisting of a primary heat pipe and an array of four secondary heat pipes were employed to transfer heat to the PCM. The primary heat pipe transports heat from the heat source to the heat sink. The secondary heat pipes transfer the extra heat from the heat source to PCM during charging process or retrieve thermal energy from PCM during discharging process. The effects of heat transfer fluid (HTF) flow rate and temperature on the thermal performance of the system were investigated for both charging and discharging processes. It was found that the HTF flow rate has a significant effect on the total charging time of the system. Increasing the HTF flow rate results in a remarkable increase in the system input thermal power. The results also showed that the discharging process is hardly affected by the HTF flow rate but HTF temperature plays an important role in both charging and discharging processes. The authors would like to acknowledge the financial supports by Temple University for the project.

  5. Saline Cavern Adiabatic Compressed Air Energy Storage Using Sand as Heat Storage Material

    Directory of Open Access Journals (Sweden)

    Martin Haemmerle

    2017-03-01

    Full Text Available Adiabatic compressed air energy storage systems offer large energy storage capacities and power outputs beyond 100MWel. Salt production in Austria produces large caverns which are able to hold pressure up to 100 bar, thus providing low cost pressurized air storage reservoirs for adiabatic compressed air energy storage plants. In this paper the results of a feasibility study is presented, which was financed by the Austrian Research Promotion Agency, with the objective to determine the adiabatic compressed air energy storage potential of Austria’s salt caverns. The study contains designs of realisable plants with capacities between 10 and 50 MWel, applying a high temperature energy storage system currently developed at the Institute for Energy Systems and Thermodynamics in Vienna. It could be shown that the overall storage potential of Austria’s salt caverns exceeds a total of 4GWhel in the year 2030 and, assuming an adequate performance of the heat exchanger, that a 10MWel adiabatic compressed air energy storage plant in Upper Austria is currently feasible using state of the art thermal turbomachinery which is able to provide a compressor discharge temperature of 400 °C.

  6. Influence of geologic layering on heat transport and storage in an aquifer thermal energy storage system

    Science.gov (United States)

    Bridger, D. W.; Allen, D. M.

    2014-01-01

    A modeling study was carried out to evaluate the influence of aquifer heterogeneity, as represented by geologic layering, on heat transport and storage in an aquifer thermal energy storage (ATES) system in Agassiz, British Columbia, Canada. Two 3D heat transport models were developed and calibrated using the flow and heat transport code FEFLOW including: a "non-layered" model domain with homogeneous hydraulic and thermal properties; and, a "layered" model domain with variable hydraulic and thermal properties assigned to discrete geological units to represent aquifer heterogeneity. The base model (non-layered) shows limited sensitivity for the ranges of all thermal and hydraulic properties expected at the site; the model is most sensitive to vertical anisotropy and hydraulic gradient. Simulated and observed temperatures within the wells reflect a combination of screen placement and layering, with inconsistencies largely explained by the lateral continuity of high permeability layers represented in the model. Simulation of heat injection, storage and recovery show preferential transport along high permeability layers, resulting in longitudinal plume distortion, and overall higher short-term storage efficiencies.

  7. Heat storage system utilizing phase change materials government rights

    Science.gov (United States)

    Salyer, Ival O.

    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.

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

    Science.gov (United States)

    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.

  9. Energy density enhancement of chemical heat storage material for magnesium oxide/water chemical heat pump

    International Nuclear Information System (INIS)

    Myagmarjav, Odtsetseg; Zamengo, Massimiliano; Ryu, Junichi; Kato, Yukitaka

    2015-01-01

    A novel candidate chemical heat storage material having higher reaction performance and higher thermal conductivity used for magnesium oxide/water chemical heat pump was developed in this study. The material, called EML, was obtained by mixing pure Mg(OH)_2 with expanded graphite (EG) and lithium bromide (LiBr), which offer higher thermal conductivity and reactivity, respectively. With the aim to achieve a high energy density, the EML composite was compressed into figure of the EML tablet (ϕ7.1 mm × thickness 3.5 mm). The compression force did not degrade the reaction conversion, and furthermore it enabled us to achieve best heat storage and output performances. The EML tablet could store heat of 815.4 MJ m_t_a_b"−"3 at 300 °C within 120 min, which corresponded to almost 4.4 times higher the heat output of the EML composite, and therefore, the EML tablet is the solution which releases more heat in a shorter time. A relatively larger volumetric gross heat output was also recorded for the EML tablet, which was greater than one attained for the EML composite at certain temperatures. As a consequence, it is expected that the EML tablet could respond more quickly to sudden demand of heat from users. It was concluded that the EML tablet demonstrated superior performances. - Highlights: • A new chemical heat storage material, donated as EML, was developed. • EML composite made from pure Mg(OH)_2, expanded graphite and lithium bromide. • EML tablet was demonstrated by compressing the EML composite. • Compression force did not degrade the conversion in dehydration and hydration. • EML tablet demonstrated superior heat storage and output performances.

  10. Tropical Drosophila ananassae of wet-dry seasons show cross resistance to heat, drought and starvation

    Directory of Open Access Journals (Sweden)

    Chanderkala Lambhod

    2017-11-01

    Full Text Available Plastic responses to multiple environmental stressors in wet or dry seasonal populations of tropical Drosophila species have received less attention. We tested plastic effects of heat hardening, acclimation to drought or starvation, and changes in trehalose, proline and body lipids in Drosophila ananassae flies reared under wet or dry season-specific conditions. Wet season flies revealed significant increase in heat knockdown, starvation resistance and body lipids after heat hardening. However, accumulation of proline was observed only after desiccation acclimation of dry season flies while wet season flies elicited no proline but trehalose only. Therefore, drought-induced proline can be a marker metabolite for dry-season flies. Further, partial utilization of proline and trehalose under heat hardening reflects their possible thermoprotective effects. Heat hardening elicited cross-protection to starvation stress. Stressor-specific accumulation or utilization as well as rates of metabolic change for each energy metabolite were significantly higher in wet-season flies than dry-season flies. Energy metabolite changes due to inter-related stressors (heat versus desiccation or starvation resulted in possible maintenance of energetic homeostasis in wet- or dry-season flies. Thus, low or high humidity-induced plastic changes in energy metabolites can provide cross-protection to seasonally varying climatic stressors.

  11. Thermochemical Heat Storage: from Reaction Storage Density to System Storage Density

    NARCIS (Netherlands)

    Jong, A.J. de; Vliet, L.D. van; Hoegaerts, C.L.G.; Roelands, C.P.M.; Cuypers, R.

    2016-01-01

    Long-term and compact storage of solar energy is crucial for the eventual transition to a 100% renewable energy economy. For this, thermochemical materials provide a promising solution. The compactness of a long-term storage system is determined by the thermochemical reaction, operating conditions,

  12. Seasonal carbohydrate storage and mobilization in bearing and non-bearing pistachio (Pistacia vera) trees.

    Science.gov (United States)

    Spann, Timothy M; Beede, Robert H; Dejong, Theodore M

    2008-02-01

    We analyzed annual carbohydrate storage and mobilization of bearing ("on") and non-bearing ("off") 'Kerman' pistachio (Pistacia vera L.) trees growing on three different rootstocks. On all rootstocks, carbohydrate storage in shoots and branches of "on" and "off" trees was lowest following the spring growth flush. In "off" trees, stored carbohydrates increased and remained high after the initial growth flush. In "on" trees, stem carbohydrates increased temporarily in early summer, but were mobilized in mid-season during kernel fill, and then increased again after nut harvest. During the dormant season, the only substantial differences in carbohydrate storage between previously "on" and "off" trees were found in the roots of the weakest rootstock. The annual carbohydrate storage and mobilization pattern in canopy branches of heavily cropped pistachio trees appeared to be driven by carbohydrate demands related to nut development and untempered by tree vigor. Mobilization of carbohydrates from current-season and 1- and 2-year-old stem wood of "on" trees during the primary period of kernel fill corresponded with the period of inflorescence bud abscission. Thus, the alternate bearing pattern associated with inflorescence bud abscission in 'Kerman' pistachio may be a function of mid-season mobilization of stored carbohydrates in current-season stems resulting in stimulation of inflorescence bud abscission.

  13. Dynamics in the microbiology of maize silage during whole-season storage

    DEFF Research Database (Denmark)

    Storm, Ida Marie Lindhardt Drejer; Kristensen, N.B.; Raun, B.M.L.

    2010-01-01

    Aims: To monitor seasonal variations in the microbiology of maize silage and to determine whether the risk of fungal spoilage varies during whole-year storage. Methods and Results: A continuous survey of 20 maize silage stacks was conducted over a period from three to 11 months after ensiling...... variations in the microbiology of maize silage over a whole storage season. The risk of fungal spoilage was highest 5-7 months after ensiling and lowest after 11 months. Significance and Impact of the Study: This information is valuable in the assessment of health risks connected with spoiled maize silage...

  14. Annual cycle solar energy utilization with seasonal storage. Part 8. Study on periodic steady state of the annual cycle energy system at a practical operation; Kisetsukan chikunetsu ni yoru nenkan cycle taiyo energy riyo system ni kansuru kenkyu. 8

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, H; Okumiya, M [Nagoya University, Nagoya (Japan)

    1997-11-25

    A study was made of the periodic steady state of the annual cycle solar energy system with seasonal heat storage at a practical operation. Cold heat in winter and warm heat in summer are stored in the seasonal storage tank, and these are each used in shift until when demand for cold/warm heat appears. Moreover, gap in quantity of cold/warm heat going in/out of the heat storage tank during a year is filled by natural energy such as solar energy, so that the system can be operated in annual cycles. Studies were conducted of the periodic unsteady term and the problem on lowering of performance during the term such as the periodic unsteady term of water temperature inside the seasonal heat storage tank and temperature of the soil around the storage tank, and the level of lowering of performance during the term, necessity of additional operation/control at the start of operation and aged deterioration of the system. Within the assumption, even if starting operation in any time of the year, the system could show the performance almost expected from the first operation year with no additional system operation and control required only at the start of operation. It is thought that the heat source selection control of heat pump largely contributes to this. 4 refs., 5 figs., 3 tabs.

  15. Wallboard with Latent Heat Storage for Passive Solar Applications; TOPICAL

    International Nuclear Information System (INIS)

    Kedl, R.J.

    2001-01-01

    Conventional wallboard impregnated with octadecane paraffin[melting point-23 C (73.5 F)] is being developed as a building material with latent heat storage for passive solar and other applications. Impregnation was accomplished simply by soaking the wallboard in molten wax. Concentrations of wax in the combined product as high as 35% by weight can be achieved. Scale-up of the soaking process, from small laboratory samples to full-sized 4- by 8-ft sheets, has been successfully accomplished. The required construction properties of wallboard are maintained after impregnation, that is, it can be painted and spackled. Long-term, high-temperature exposure tests and thermal cycling tests showed no tendency of the paraffin to migrate within the wallboard, and there was no deterioration of thermal energy storage capacity. In support of this concept, a computer model was developed to handle thermal transport and storage by a phase change material (PCM) dispersed in a porous media. The computer model was confirmed by comparison with known analytical solutions and also by comparison with temperatures measured in wallboard during an experimentally generated thermal transient. Agreement between the model and known solution was excellent. Agreement between the model and thermal transient was good, only after the model was modified to allow the PCM to melt over a temperature range, rather than at a specific melting point. When the melting characteristics of the PCM (melting point, melting range, and heat of fusion), as determined from a differential scanning calorimeter plot, were used in the model, agreement between the model and transient data was very good. The confirmed computer model may now be used in conjunction with a building heating and cooling code to evaluate design parameters and operational characteristics of latent heat storage wallboard for passive solar applications

  16. Integrated heat exchanger design for a cryogenic storage tank

    Energy Technology Data Exchange (ETDEWEB)

    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.

  17. Active latent heat storage with a screw heat exchanger - experimental results for heat transfer and concept for high pressure steam

    Science.gov (United States)

    Zipf, Verena; Willert, Daniel; Neuhäuser, Anton

    2016-05-01

    An innovative active latent heat storage concept was invented and developed at Fraunhofer ISE. It uses a screw heat exchanger (SHE) for the phase change during the transport of a phase change material (PCM) from a cold to a hot tank or vice versa. This separates heat transfer and storage tank in comparison to existing concepts. A test rig has been built in order to investigate the heat transfer coefficients of the SHE during melting and crystallization of the PCM. The knowledge of these characteristics is crucial in order to assess the performance of the latent heat storage in a thermal system. The test rig contains a double shafted SHE, which is heated or cooled with thermal oil. The overall heat transfer coefficient U and the convective heat transfer coefficient on the PCM side hPCM both for charging and discharging have been calculated based on the measured data. For charging, the overall heat transfer coefficient in the tested SHE was Uch = 308 W/m2K and for discharging Udis = 210 W/m2K. Based on the values for hPCM the overall heat transfer coefficients for a larger SHE with steam as heat transfer fluid and an optimized geometry were calculated with Uch = 320 W/m2K for charging and Udis = 243 W/m2K for discharging. For pressures as high as p = 100 bar, an SHE concept has been developed, which uses an organic fluid inside the flight of the SHE as working media. With this concept, the SHE can also be deployed for very high pressure, e.g. as storage in solar thermal power plants.

  18. Modeling Pumped Thermal Energy Storage with Waste Heat Harvesting

    Science.gov (United States)

    Abarr, Miles L. Lindsey

    This work introduces a new concept for a utility scale combined energy storage and generation system. The proposed design utilizes a pumped thermal energy storage (PTES) system, which also utilizes waste heat leaving a natural gas peaker plant. This system creates a low cost utility-scale energy storage system by leveraging this dual-functionality. This dissertation first presents a review of previous work in PTES as well as the details of the proposed integrated bottoming and energy storage system. A time-domain system model was developed in Mathworks R2016a Simscape and Simulink software to analyze this system. Validation of both the fluid state model and the thermal energy storage model are provided. The experimental results showed the average error in cumulative fluid energy between simulation and measurement was +/- 0.3% per hour. Comparison to a Finite Element Analysis (FEA) model showed heat transfer. The system model was used to conduct sensitivity analysis, baseline performance, and levelized cost of energy of a recently proposed Pumped Thermal Energy Storage and Bottoming System (Bot-PTES) that uses ammonia as the working fluid. This analysis focused on the effects of hot thermal storage utilization, system pressure, and evaporator/condenser size on the system performance. This work presents the estimated performance for a proposed baseline Bot-PTES. Results of this analysis showed that all selected parameters had significant effects on efficiency, with the evaporator/condenser size having the largest effect over the selected ranges. Results for the baseline case showed stand-alone energy storage efficiencies between 51 and 66% for varying power levels and charge states, and a stand-alone bottoming efficiency of 24%. The resulting efficiencies for this case were low compared to competing technologies; however, the dual-functionality of the Bot-PTES enables it to have higher capacity factor, leading to 91-197/MWh levelized cost of energy compared to 262

  19. Comparison of Dry Gas Seasonal Storage with CO2 Storage and Re-Use Potential

    OpenAIRE

    Killerud, Marie

    2013-01-01

    To make large-scale CO2 storage economic, many groups have proposed using CO2in EOR projects to create value for CO2 storage. However, CO2 EOR projectsgenerally require a large and variable supply of CO2 and consequently may requiretemporary storage of CO2 in geological formations. In order to store CO2 atoffshore sites as a source for CO2 EOR projects, the CO2 needs to be extractedfrom a storage site to a certain extent. Alternatively, CO2 EOR projects maybe developed alongside saline aquife...

  20. HEAT STORAGE SYSTEM WITH PHASE CHANGE MATERIALS IN COGENERATION UNITS: STUDY OF PRELIMINARY MODEL

    Directory of Open Access Journals (Sweden)

    Claudio Caprara

    2008-12-01

    Full Text Available The continuous increase in the mechanization of farm activities, the rise in fuel prices and the environmental aspects concerning gas emissions are the main driving forces behind efforts toward more effective use of renewable energy sources and cogeneration systems even in agricultural and cattle farms. Nevertheless these systems are still not very suitable for this purpose because of their little flexibility in following the changing energy demand as opposed to the extremely various farm load curves, both in daytime and during the year. In heat recovery systems, the available thermal energy supply is always linked to power production, thus it does not usually coincide in time with the heat demand. Hence some form of thermal energy storage (TES is necessary in order to reach the most effective utilization of the energy source. This study deals with the modelling of a packed bed latent heat TES unit, integrating a cogeneration system made up of a reciprocating engine. The TES unit contains phase change materials (PCMs filled in spherical capsules, which are packed in an insulated cylindrical storage tank. Water is used as heat transfer fluid (HTF to transfer heat from the tank to the final uses, and exhausts from the engine are used as thermal source. PCMs are considered especially for their large heat storage capacity and their isothermal behaviour during the phase change processes. Despite their high energy storage density, most of them have an unacceptably low thermal conductivity, hence PCMs encapsulation technique is adopted in order to improve heat transfer. The special modular configuration of heat exchange tubes and the possibility of changing water flow through them allow to obtain the right amount of thermal energy from the tank, according to the hourly demand of the day. The model permits to choose the electrical load of the engine, the dimensions of the tank and the spheres, thickness and diameter of heat exchanger and the nature of

  1. Method and equipment to utilize solar heat. [paraffin used as heat storage material

    Energy Technology Data Exchange (ETDEWEB)

    Poellein, H

    1976-09-16

    In this process, solar radiation is converted into heat by means of absorbers. The heat transferred to a liquid is led in forced circulation, first into a heat storage device and then into a water heater. The cooled-down liquid is rercirculated. The storage material used here is paraffin. A measuring and control device is provided to switch from periods with solar radiation to periods where only stored energy is consumed. This device consists of a photocell measuring the incoming sunlight and a temperarure sensor. The control system is put into operation by a combination of the two measured values. The heat accumulator consists of several elements connected in parallel. A control device makes sure that only one accumulator element at a time is part of the circuit. The absorbers, as usual, consists of the absorber plate proper and a cover plate.

  2. Preparation of fine powdered composite for latent heat storage

    Energy Technology Data Exchange (ETDEWEB)

    Fořt, Jan, E-mail: jan.fort.1@fsv.cvut.cz; Trník, Anton, E-mail: anton.trnik@fsv.cvut.cz; Pavlíková, Milena, E-mail: milena.pavlikova@fsv.cvut.cz; Pavlík, Zbyšek, E-mail: pavlikz@fsv.cvut.cz [Department of Materials Engineering and Chemistry, Faculty of Civil Engineering, Czech Technical University in Prague, Thákurova 7, 166 29 Prague (Czech Republic); Pomaleski, Marina, E-mail: marina-pomaleski@fsv.cvut.cz [Faculty of Civil Engineering, Architecture and Urbanism, University of Campinas, R. Saturnino de Brito 224, 13083-889 Campinas – SP (Brazil)

    2016-07-07

    Application of latent heat storage building envelope systems using phase-change materials represents an attractive method of storing thermal energy and has the advantages of high-energy storage density and the isothermal nature of the storage process. This study deals with a preparation of a new type of powdered phase change composite material for thermal energy storage. The idea of a composite is based upon the impregnation of a natural silicate material by a reasonably priced commercially produced pure phase change material and forming the homogenous composite powdered structure. For the preparation of the composite, vacuum impregnation method is used. The particle size distribution accessed by the laser diffraction apparatus proves that incorporation of the organic phase change material into the structure of inorganic siliceous pozzolana does not lead to the clustering of the particles. The compatibility of the prepared composite is characterized by the Fourier transformation infrared analysis (FTIR). Performed DSC analysis shows potential of the developed composite for thermal energy storage that can be easily incorporated into the cement-based matrix of building materials. Based on the obtained results, application of the developed phase change composite can be considered with a great promise.

  3. A method to determine stratification efficiency of thermal energy storage processes independently from storage heat losses

    DEFF Research Database (Denmark)

    Haller, M.Y.; Yazdanshenas, Eshagh; Andersen, Elsa

    2010-01-01

    process is in agreement with the first law of thermodynamics. A comparison of the stratification efficiencies obtained from experimental results of charging, standby, and discharging processes gives meaningful insights into the different mixing behaviors of a storage tank that is charged and discharged......A new method for the calculation of a stratification efficiency of thermal energy storages based on the second law of thermodynamics is presented. The biasing influence of heat losses is studied theoretically and experimentally. Theoretically, it does not make a difference if the stratification...

  4. SODHA. A data program for minimizing the cost function of a solar farm with storage connected to a district heating system

    Energy Technology Data Exchange (ETDEWEB)

    Haakansson, R; Rolandsson, S

    1982-05-03

    SODHA is a program for minimizing the investment needed for a solar plant supplying a district heating system. The plant consists of a solar farm, storage and a heat exchanger connected to a district heating network. By using SODHA it is possible to optimize solar collector area storage volume, insulation thickness and magnitude of heat exchanger. The calculation gives the best estimated configuration of the system, within given margins and specified regulation principles. The program can be used for an arbitrary period, e.g. one season (year). This work is financed by NE, the National Swedish Board for Energy Source Development.

  5. Lauric and palmitic acids eutectic mixture as latent heat storage material for low temperature heating applications

    International Nuclear Information System (INIS)

    Tuncbilek, Kadir; Sari, Ahmet; Tarhan, Sefa; Erguenes, Gazanfer; Kaygusuz, Kamil

    2005-01-01

    Palmitic acid (PA, 59.8 deg. C) and lauric acid (LA, 42.6 deg. C) are phase change materials (PCM) having quite high melting temperatures which can limit their use in low temperature solar applications such as solar space heating and greenhouse heating. However, their melting temperatures can be tailored to appropriate value by preparing a eutectic mixture of the lauric and the palmitic acids. In the present study, the thermal analysis based on differential scanning calorimetry (DSC) technique shows that the mixture of 69.0 wt% LA and 31 wt% PA forms a eutectic mixture having melting temperature of 35.2 deg. C and the latent heat of fusion of 166.3 J g -1 . This study also considers the experimental determination of the thermal characteristics of the eutectic mixture during the heat charging and discharging processes. Radial and axial temperature distribution, heat transfer coefficient between the heat transfer fluid (HTF) pipe and the PCM, heat recovery rate and heat charging and discharging fractions were experimentally established employing a vertical concentric pipe-in-pipe energy storage system. The changes of these characteristics were evaluated with respect to the effect of inlet HTF temperature and mass flow rate. The DSC thermal analysis and the experimental results indicate that the LA-PA eutectic mixture can be a potential material for low temperature thermal energy storage applications in terms of its thermo-physical and thermal characteristics

  6. Impact of seasonality and storage of semen on epigenetics in swine placenta and fetal livers

    Science.gov (United States)

    Epigenetics includes the study of external factors that can influence the expression of genes by altering accessibility of DNA through methylation and histone modification. To investigate the influence of: season (semen collection and breeding), absolute sperm head-shape change, and semen storage on...

  7. Michigan residential heating oil and propane price survey: 1995-1996 heating season. Final report

    International Nuclear Information System (INIS)

    Moriarty, C.

    1996-05-01

    This report summarizes the results of a survey of residential No. 2 distillate fuel (home heating oil) and liquefied petroleum gas (propane) prices over the 1995--1996 heating season in Michigan. The Michigan's Public Service Commission (MPSC) conducted the survey under a cooperative agreement with the US Department of Energy's (DOE) Energy Information Administration (EIA). This survey was funded in part by a grant from the DOE. From October 1995 through March 1996, the MPSC surveyed participating distributors by telephone for current residential retail home heating oil and propane prices. The MPSC transmitted the data via a computer modem to the EIA using the Petroleum Electronic Data Reporting Option (PEDRO). Survey results were published in aggregate on the MPSC World Wide Web site at http://ermisweb.state.mi.us/shopp. The page was updated with both residential and wholesale prices immediately following the transmission of the data to the EIA. The EIA constructed the survey using a sample of Michigan home heating oil and propane retailers. The sample accounts for different sales volumes, geographic location, and sources of primary supply

  8. Assessment of feasible strategies for seasonal underground hydrogen storage in a saline aquifer

    Science.gov (United States)

    Sáinz-García, Alvaro; Abarca, Elena; Rubí, Violeta; Grandia, Fidel

    2017-04-01

    Renewable energies are unsteady, which results in temporary mismatches between demand and supply. The conversion of surplus energy to hydrogen and its storage in geological formations is one option to balance this energy gap. This study evaluates the feasibility of seasonal storage of hydrogen produced from wind power in Castilla-León region (northern Spain). A 3D multiphase numerical model is used to test different extraction well configurations during three annual injection-production cycles in a saline aquifer. Results demonstrate that underground hydrogen storage in saline aquifers can be operated with reasonable recovery ratios. A maximum hydrogen recovery ratio of 78%, which represents a global energy efficiency of 30%, has been estimated. Hydrogen upconing emerges as the major risk on saline aquifer storage. However, shallow extraction wells can minimize its effects. Steeply dipping geological structures are key for an efficient hydrogen storage.

  9. Energy system investment model incorporating heat pumps with thermal storage in buildings and buffer tanks

    International Nuclear Information System (INIS)

    Hedegaard, Karsten; Balyk, Olexandr

    2013-01-01

    Individual compression heat pumps constitute a potentially valuable resource in supporting wind power integration due to their economic competitiveness and possibilities for flexible operation. When analysing the system benefits of flexible heat pump operation, effects on investments should be taken into account. In this study, we present a model that facilitates analysing individual heat pumps and complementing heat storages in integration with the energy system, while optimising both investments and operation. The model incorporates thermal building dynamics and covers various heat storage options: passive heat storage in the building structure via radiator heating, active heat storage in concrete floors via floor heating, and use of thermal storage tanks for space heating and hot water. It is shown that the model is well qualified for analysing possibilities and system benefits of operating heat pumps flexibly. This includes prioritising heat pump operation for hours with low marginal electricity production costs, and peak load shaving resulting in a reduced need for peak and reserve capacity investments. - Highlights: • Model optimising heat pumps and heat storages in integration with the energy system. • Optimisation of both energy system investments and operation. • Heat storage in building structure and thermal storage tanks included. • Model well qualified for analysing system benefits of flexible heat pump operation. • Covers peak load shaving and operation prioritised for low electricity prices

  10. Trial production of ceramic heat storage unit and study on thermal properties and thermal characteristics of the heat storage unit. Mixed salts of Na2CO3, MgCl2 and CaCl2 as heat storage medium

    International Nuclear Information System (INIS)

    Shiina, Yasuaki

    1998-12-01

    Heat storage technique of high temperature and high density latent heat can be applied to an accumulator of heat generated by nuclear power plant in the night and to a thermal load absorber. For the practical use of the heat storage technique, it is important to improve heat exchange characteristics between heat storage medium, such as molten salts, and heat transfer fluid because of low thermal conductivity of the molten salts, to improve durability among molten salt and structure materials and to develop the molten salt with stable thermal properties for a long period. Considering the possibility for the improvement of heat exchange characteristics of phase change heat storage system by absorbing molten salt in porous ceramics with high thermal conductivity, high temperature proof and high resistance to corrosion, several samples of the ceramics heat storage unit were made. Basic characteristics of the samples (strength, thermal properties, temperature characteristics during phase change) were measured experimentally and analytically to study the utility and applicability of the samples for the heat storage system. The results show that the heat storage unit should be used in inactive gas condition because water in the air absorbed in the molten salts would yield degeneration of properties and deterioration of strength and that operation temperature should be confined near fusion temperature because some molten salts would be vaporized and mass would be decreased in considerable high temperature. The results also show that when atmospheric temperature changes around the melting temperature, change in ceramic temperature becomes small. This result suggests the possibility that ceramic heat storage unit could be used as thermal load absorber. (J.P.N.)

  11. Optimal Energy Management of Combined Cooling, Heat and Power in Different Demand Type Buildings Considering Seasonal Demand Variations

    Directory of Open Access Journals (Sweden)

    Akhtar Hussain

    2017-06-01

    Full Text Available In this paper, an optimal energy management strategy for a cooperative multi-microgrid system with combined cooling, heat and power (CCHP is proposed and has been verified for a test case of building microgrids (BMGs. Three different demand types of buildings are considered and the BMGs are assumed to be equipped with their own combined heat and power (CHP generators. In addition, the BMGs are also connected to an external energy network (EEN, which contains a large CHP, an adsorption chiller (ADC, a thermal storage tank, and an electric heat pump (EHP. By trading the excess electricity and heat energy with the utility grid and EEN, each BMG can fulfill its energy demands. Seasonal energy demand variations have been evaluated by selecting a representative day for the two extreme seasons (summer and winter of the year, among the real profiles of year-round data on electricity, heating, and cooling usage of all the three selected buildings. Especially, the thermal energy management aspect is emphasized where, bi-lateral heat trading between the energy supplier and the consumers, so-called energy prosumer concept, has been realized. An optimization model based on mixed integer linear programming has been developed for minimizing the daily operation cost of the EEN while fulfilling the energy demands of the BMGs. Simulation results have demonstrated the effectiveness of the proposed strategy.

  12. Improvement in Performance of a Thermochemical Heat Storage System by Implementing an Internal Heat Recovery System

    NARCIS (Netherlands)

    Gaeini, M.; Saris, L.; Zondag, H.A.; Rindt, C.C.M.

    A lab-scale prototype of a thermochemical heat storage system, employing a water-zeolite 13X as the working pair, is designed and optimized for providing hot tap water. During the hydration process, humid air is introduced to the packed bed reactor filled with dehydrated zeolite 13X, and the

  13. Thermal energy storage using thermo-chemical heat pump

    International Nuclear Information System (INIS)

    Hamdan, M.A.; Rossides, S.D.; Haj Khalil, R.

    2013-01-01

    Highlights: ► Understanding of the performance of thermo chemical heat pump. ► Tool for storing thermal energy. ► Parameters that affect the amount of thermal stored energy. ► Lithium chloride has better effect on storing thermal energy. - Abstract: A theoretical study was performed to investigate the potential of storing thermal energy using a heat pump which is a thermo-chemical storage system consisting of water as sorbet, and sodium chloride as the sorbent. The effect of different parameters namely; the amount of vaporized water from the evaporator, the system initial temperature and the type of salt on the increase in temperature of the salt was investigated and hence on the performance of the thermo chemical heat pump. It was found that the performance of the heat pump improves with the initial system temperature, with the amount of water vaporized and with the water remaining in the system. Finally it was also found that lithium chloride salt has higher effect on the performance of the heat pump that of sodium chloride.

  14. Experimental research on thermal characteristics of a hybrid thermocline heat storage system

    International Nuclear Information System (INIS)

    Yin, Huibin; Ding, Jing; Yang, Xiaoxi

    2014-01-01

    Considering the high-temperature thermal utilization of solar energy as the research background in this paper and focussing on the heat storage process, a kind of hybrid thermocline heat storage method in multi-scale structure and relevant experimental systems are designed by using the mixed molten nitrate salt as the heat storage medium and two representative porous materials, i.e. zirconium ball and silicon carbide (SiC) foam, as the heat storage fillers. The fluid flow and heat storage performance of molten salt in multi-scale structure are experimentally investigated. The results show that the theoretical heat storage efficiencies amongst the three experimental heat storage manners are less than 80% because of the existence of thermocline layers. Comparing to the single-phase molten salt heat storage, the two hybrid thermocline heat storage manners with porous fillers lead to a certain decrease in the effective heat storage capacity. The presence of porous fillers can also help to maintain the molten salt fluid as ideal gravity flow or piston flow and partially replace expensive molten salt. Therefore, it requires a combination of heat storage capacity and economical consideration for optimization design when similar spherical particles or foam ceramics are employed as the porous fillers. -- Highlights: • A hybrid thermocline heat storage method in multi-scale structure is developed. • The fluid flow and heat storage performance are experimentally investigated. • Stable thermocline can form in single tank for the experimental cases. • The hybrid thermocline heat storage with porous filler is promising

  15. Heat storage in the Hettangian aquifer in Berlin - results from a column experiment

    Science.gov (United States)

    Milkus, Chri(Sch)augott

    2015-04-01

    Aquifer Thermal Energy Storage (ATES) is a sustainable alternative for storage and seasonal availability of thermal energy. However, its impact on the subsurface flow regime is not well known. In Berlin (Germany), the Jurassic (Hettangian) sandstone aquifer with highly mineralized groundwater (TDS 27 g/L) is currently used for heat storage. The aim of this study was to examine the hydrogeochemical changes that are caused by the induced temperature shift and its effects on the hydraulic permeability of the aquifer. Column experiments were conducted, in which stainless steel columns were filled with sediment from the aquifer and flushed with native groundwater for several weeks. The initial temperature of the experiment was 20°C, comparable to the in-situ conditions within the aquifer. After reaching equilibrium between sediment and water, the temperature was increased to simulate heating of the aquifer. During the experiment, physical and chemical parameters (pH, ORP, dissolved oxygen and dissolved carbon dioxide) were measured at the outflow of the column and the effluent water was sampled. Using a Scanning Electron Microscope, the deposition of precipitated minerals and biofilm on sediment grains was analyzed. Changes in hydraulic properties of the sediment were studied by the use of tracer tests with Uranin.

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

    Energy Technology Data Exchange (ETDEWEB)

    Mathur, Anoop [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

  17. Development of evaluation method for heat removal design of dry storage facilities. pt. 1. Heat removal test on vault storage system of cross flow type

    International Nuclear Information System (INIS)

    Sakamoto, Kazuaki; Koga, Tomonari; Wataru, Masumi; Hattori, Yasuo

    1997-01-01

    The report describes the result of heat removal test of passive cooling vault storage system of cross flow type using 1/5 scale model. Based on a prospect of steady increase in the amount of spent fuel, it is needed to establish large capacity dry storage technologies for spent fuel. Air flow patterns, distributions of air temperature and velocity were measured, by which heat removal characteristics of the system were made clear. Air flow patterns in the storage module depended on the ratio of the buoyant force to the inertial force; the former generated by the difference of air temperatures and the height of the storage module, the latter by the difference of air densities between the outlet of the storage module and ambience and the height of the chimney of the storage facility. A simple method to estimate air flow patterns in the storage module was suggested, where Ri(Richardson) number was applied to represent the ratio. Moreover, heat transfer coefficient from a model of storage tube to cooling air was evaluated, and it was concluded that the generalized expression of heat transfer coefficient for common heat exchangers could be applied to the vault storage system of cross flow type, in which dozens of storage tubes were placed in a storage module. (author)

  18. State heating oil and propane program: 1995-96 heating season. Final report

    International Nuclear Information System (INIS)

    1996-01-01

    This is a summary report of the New Hampshire Governor's Office of Energy and Community Services (ECS) participation in the State Heating Oil and Propane Program (SHOPP) for the 1995/96 heating season. SHOPP is a cooperative effort, linking energy offices in East Coast and Midwest states, with the Department of Energy (DOE), Energy Information Administration (EIA) for the purpose of collecting retail price data for heating oil and propane. The program funded by the participating state with a matching grant from DOE. EIA provides ECS with a list of oil and propane retailers that serve customers in New Hampshire. In turn ECS conduct phone surveys twice per month from October through March to determine the average retail price for each fuel. Data collected by ECS is entered into the Petroleum Electronic Data Reporting Option (PEDRO) and transmitted via modem to EIA. The results of the state retail price surveys along with wholesale prices, supply, production and stock levels for oil, and propane are published by EIA in the Weekly Petroleum Status Report. Data is also published electronically via the internet or through the Electronic Publication System

  19. Nanoparticles for heat transfer and thermal energy storage

    Science.gov (United States)

    Singh, Dileep; Cingarapu, Sreeram; Timofeeva, Elena V.; Moravek, Michael

    2015-07-14

    An article of manufacture and method of preparation thereof. The article of manufacture and method of making the article includes an eutectic salt solution suspensions and a plurality of nanocrystalline phase change material particles having a coating disposed thereon and the particles capable of undergoing the phase change which provides increase in thermal energy storage. In addition, other articles of manufacture can include a nanofluid additive comprised of nanometer-sized particles consisting of copper decorated graphene particles that provide advanced thermal conductivity to heat transfer fluids.

  20. Thermal energy storage for industrial waste heat recovery

    Science.gov (United States)

    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.

  1. Annex to Solar heat storages in district heating networks. Comprehensive list of Danish literature and R and D projects

    Energy Technology Data Exchange (ETDEWEB)

    Ellehauge, K. (Ellehauge og Kildemoes, AArhus (DK)); Engberg Pedersen, T. (COWI A/S, Kgs. Lyngby (DK))

    2007-07-15

    This annex relates to the report 'Solar heat storages in district heating networks', which has been elaborated to inform about the Danish experiences and findings on the use of central solar heating plants in district heating networks, especially with the focus on the development of the storage part of the systems. The report has been funded as part of the IEE PREHEAT cooperation and by Energinet.dk, project no. 2006-2-6750. (au)

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

    Science.gov (United States)

    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.

  3. Parametrical analysis of latent heat and cold storage for heating and cooling of rooms

    International Nuclear Information System (INIS)

    Osterman, E.; Hagel, K.; Rathgeber, C.; Butala, V.; Stritih, U.

    2015-01-01

    One of the problems we are facing today is the energy consumption minimization, while maintaining the indoor thermal comfort in buildings. A potential solution to this issue is use of phase change materials (PCMs) in thermal energy storage (TES), where cold gets accumulated during the summer nights in order to reduce cooling load during the day. In winter, on the other hand, heat from solar air collector is stored for evening and morning hours when solar radiation is not available. The main objective of the paper is to examine experimentally whether it is possible to use such a storage unit for heating as well as for cooling. For this purpose 30 plates filled with paraffin (melting point around 22°C) were positioned into TES and applied with the same initial and boundary conditions as they are expected in reality. Experimental work covered flow visualization, measurements of air velocity in the channels between the plates, parametric analysis in conjunction with TES thermal response and measurements of the pressure drops. The results indicate that this type of storage technology could be advantageously used in real conditions. For optimized thermal behavior, only plate thickness should be reduced. - Highlights: • Thermal properties of paraffin RT22HC were measured. • Flow visualization was carried out and velocity between plates was measured. • Thermal and pressure drop analysis were performed. • Melting times are too long however, use of storage tank for heating and cooling looks promising

  4. Research programme 'Active Solar Energy Use - Solar Heating and Heat Storage'. Activities and projects 2003; Programme 'Solaire actif - Chaleur et Stockage de chaleur'. Activites et projets en 2003

    Energy Technology Data Exchange (ETDEWEB)

    Hadorn, J.-C. [Base Consultants, Geneva (Switzerland); Renaud, P. [Planair SA, La Sagne (Switzerland)

    2003-07-01

    In this report by the research, development and demonstration (RD+D) programme coordinators the objectives, activities and main results in the area of solar heating and heat storage in Switzerland are presented for 2003. In a stagnating market environment the strategy of the Swiss Federal Office of Energy mainly consists in improving the quality and durability of solar collectors and materials, optimizing combisystems for space heating and domestic hot water preparation, searching for storage systems with a higher energy storage density than in the case of sensible heat storage in water, developing coloured solar collectors for more architectonic freedom, and finalizing a seasonal heat storage project for 100 dwellings to demonstrate the feasibility of solar fractions larger than 50% in apartment houses. Support was granted to the Swiss Testing Facility SPF in Rapperswil as in previous years; SPF was the first European testing institute to perform solar collector labeling according to the new rules of the 'Solar Keymark', introduced in cooperation with the European Committee for Standardization CEN. Several 2003 projects were conducted within the framework of the Solar Heating and Cooling Programme of the International Energy Agency IEA. Computerized simulation tools were improved. With the aim of jointly producing high-temperature heat and electric power a solar installation including a concentrating collector and a thermodynamic machine based on a Rankine cycle is still being developed. Seasonal underground heat storage was studied in detail by means of a validated computer simulation programme. Design guidelines were obtained for such a storage used in the summer time for cooling and in the winter time for space heating via a heat pump: depending on the ratio 'summer cooling / winter heating', cooling requires a cooling machine, or direct cooling without such a machine is possible. The report ends up with the list of all supported RD

  5. Heat of Fusion Storage with High Solar Fraction for Solar Low Energy Buildings

    DEFF Research Database (Denmark)

    Schultz, Jørgen Munthe; Furbo, Simon

    2006-01-01

    to achieve 100% coverage of space heating and domestic hot water in a low energy house in a Danish climate with a solar heating system with 36 m² flat plate solar collector and approximately 10 m³ storage with sodium acetate. A traditional water storage solution aiming at 100% coverage will require a storage...... of the storage to cool down below the melting point without solidification preserving the heat of fusion energy. If the supercooled storage reaches the surrounding temperature no heat loss will take place until the supercooled salt is activated. The investigation shows that this concept makes it possible...

  6. Phase Change Energy Storage Material Suitable for Solar Heating System

    Science.gov (United States)

    Li, Xiaohui; Li, Haihua; Zhang, Lihui; Liu, Zhenfa

    2018-01-01

    Differential scanning calorimetry (DSC) was used to investigate the thermal properties of palmitic acid, myristic acid, laurel acid and the binary composite of palmitic/laurel acid and palmitic/myristic acid. The results showed that the phase transition temperatures of the three monomers were between 46.9-65.9°C, and the latent heats were above 190 J/g, which could be used as solar energy storage material. When the mass ratio of Palmitic acid and myristic was 1:1, the eutectic mixture could be formed. The latent heat of the eutectic mixture was 186.6 J/g, the melting temperature and the solidification temperature was 50.6°C and 43.8°C respectively. The latent heat of phase change and the melting temperature had not obvious variations after 400 thermal cycles, which proved that the binary composite had good thermal stability and was suitable for solar floor radiant heating system.

  7. Flat plate solar air heater with latent heat storage

    Science.gov (United States)

    Touati, B.; Kerroumi, N.; Virgone, J.

    2017-02-01

    Our work contains two parts, first is an experimental study of the solar air heater with a simple flow and forced convection, we can use thatlaste oneit in many engineering's sectors as solardrying, space heating in particular. The second part is a numerical study with ansys fluent 15 of the storage of part of this solar thermal energy produced,using latent heat by using phase change materials (PCM). In the experimental parts, we realize and tested our solar air heater in URER.MS ADRAR, locate in southwest Algeria. Where we measured the solarradiation, ambient temperature, air flow, thetemperature of the absorber, glasses and the outlet temperature of the solar air heater from the Sunrise to the sunset. In the second part, we added a PCM at outlet part of the solar air heater. This PCM store a part of the energy produced in the day to be used in peak period at evening by using the latent heat where the PCMs present a grateful storagesystem.A numerical study of the fusion or also named the charging of the PCM using ANSYS Fluent 15, this code use the method of enthalpies to solve the fusion and solidification formulations. Furthermore, to improve the conjugate heat transfer between the heat transfer fluid (Air heated in solar plate air heater) and the PCM, we simulate the effect of adding fins to our geometry. Also, four user define are write in C code to describe the thermophysicalpropriety of the PCM, and the inlet temperature of our geometry which is the temperature at the outflow of the solar heater.

  8. The influence of Critical Zone structure on runoff paths, seasonal water storage, and ecosystem composition

    Science.gov (United States)

    Hahm, W. J.; Dietrich, W. E.; Rempe, D.; Dralle, D.; Dawson, T. E.; Lovill, S.; Bryk, A.

    2017-12-01

    Understanding how subsurface water storage mediates water availability to ecosystems is crucial for elucidating linkages between water, energy, and carbon cycles from local to global scales. Earth's Critical Zone (the CZ, which extends from the top of the vegetation canopy downward to fresh bedrock) includes fractured and weathered rock layers that store and release water, thereby contributing to ecosystem water supplies, and yet are not typically represented in land-atmosphere models. To investigate CZ structural controls on water storage dynamics, we intensively studied field sites in a Mediterranean climate where winter rains arrive months before peak solar energy availability, resulting in strong summertime ecosystem reliance on stored subsurface water. Intra-hillslope and catchment-wide observations of CZ water storage capacity across a lithologic boundary in the Franciscan Formation of the Northern California Coast Ranges reveal large differences in the thickness of the CZ and water storage capacity that result in a stark contrast in plant community composition and stream behavior. Where the CZ is thick, rock moisture storage supports forest transpiration and slow groundwater release sustains baseflow and salmon populations. Where the CZ is thin, limited water storage is used by an oak savanna ecosystem, and streams run dry in summer due to negligible hillslope drainage. At both sites, wet season precipitation replenishes the dynamic storage deficit generated during the summer dry season, with excess winter rains exiting the watersheds via storm runoff as perched groundwater fracture flow at the thick-CZ site and saturation overland flow at the thin-CZ site. Annual replenishment of subsurface water storage even in severe drought years may lead to ecosystem resilience to climatic perturbations: during the 2011-2015 drought there was not widespread forest die-off in the study area.

  9. Inter-seasonal variability in baseflow recession rates: The role of aquifer antecedent storage in central California watersheds

    Science.gov (United States)

    Bart, Ryan; Hope, Allen

    2014-11-01

    Baseflow recession rates vary inter-seasonally in many watersheds. This variability is generally associated with changes in evapotranspiration; however, an additional and less studied control over inter-seasonal baseflow recession rates is the effect of aquifer antecedent storage. Understanding the role of aquifer antecedent storage on baseflow recession rates is crucial for Mediterranean-climate regions, where seasonal asynchronicity of precipitation and energy levels produces large inter-seasonal differences in aquifer storage. The primary objective of this study was to elucidate the relation between aquifer antecedent storage and baseflow recession rates in four central California watersheds using antecedent streamflow as a surrogate for watershed storage. In addition, a parsimonious storage-discharge model consisting of two nonlinear stores in parallel was developed as a heuristic tool for interpreting the empirical results and providing insight into how inter-seasonal changes in aquifer antecedent storage may affect baseflow recession rates. Antecedent streamflow cumulated from the beginning of the wateryear was found to be the strongest predictor of baseflow recession rates, indicating that inter-seasonal differences in aquifer storage are a key control on baseflow recession rates in California watersheds. Baseflow recession rates and antecedent streamflow exhibited a negative power-law relation, with baseflow recession rates decreasing by up to two orders of magnitude as antecedent streamflow levels increased. Inference based on the storage-discharge model indicated that the dominant source of recession flow shifted from small, rapid response aquifers at the beginning of the wet season to large, seasonal aquifers as the wet season progressed. Aquifer antecedent storage in California watersheds should be accounted for along with evapotranspiration when characterizing baseflow recession rates.

  10. Heat transfer and thermal storage performance of an open thermosyphon type thermal storage unit with tubular phase change material canisters

    International Nuclear Information System (INIS)

    Wang, Ping-Yang; Hu, Bo-Wen; Liu, Zhen-Hua

    2015-01-01

    Highlights: • A novel open heat pipe thermal storage unit is design to improve its performance. • Mechanism of its operation is phase-change heat transfer. • Tubular canisters with phase change material were placed in thermal storage unit. • Experiment and analysis are carried out to investigate its operation properties. - Abstract: A novel open thermosyphon-type thermal storage unit is presented to improve design and performance of heat pipe type thermal storage unit. In the present study, tubular canisters filled with a solid–liquid phase change material are vertically placed in the middle of the thermal storage unit. The phase change material melts at 100 °C. Water is presented as the phase-change heat transfer medium of the thermal storage unit. The tubular canister is wrapped tightly with a layer of stainless steel mesh to increase the surface wettability. The heat transfer mechanism of charging/discharging is similar to that of the thermosyphon. Heat transfer between the heat resource or cold resource and the phase change material in this device occurs in the form of a cyclic phase change of the heat-transfer medium, which occurs on the surface of the copper tubes and has an extremely high heat-transfer coefficient. A series of experiments and theoretical analyses are carried out to investigate the properties of the thermal storage unit, including power distribution, start-up performance, and temperature difference between the phase change material and the surrounding vapor. The results show that the whole system has excellent heat-storage/heat-release performance

  11. Seasonal distributions of diabatic heating during the First GARP Global Experiment

    OpenAIRE

    Ying Wei, Ming; Johnson, Donald R.; Townsend, Ronald D.

    2011-01-01

    The seasonal and annual global distributions of diabatic heating during the First GARP Global Experiment (FGGE) are estimated using the isentropic mass continuity equation. The data used are from the FGGE Level IIIa analyses generated by the United States National Meteorological Center. Spatially and temporally coherent diabatic heating distributions are obtained from the isentropic planetary scale mass circulation that is forced by large-scale heat sources and sinks. The diabatic heating in...

  12. Seasonal mixed layer heat balance of the southwestern tropical Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Foltz, G.R.; Vialard, J.; PraveenKumar, B.; McPhaden, M.J.

    from a long-term moored buoy are used in conjunction with satellite, in situ, and atmospheric reanalysis datasets to analyze the seasonal mixed layer heat balance in the thermocline ridge region of the southwestern tropical Indian Ocean. This region...

  13. Simulation of heat storages and associated heat budgets in the Pacific Ocean: 2. Interdecadal timescale

    Science.gov (United States)

    Auad, Guillermo; Miller, Arthur J.; White, Warren B.

    1998-11-01

    We use a primitive equation isopycnal model of the Pacific Ocean to simulate and diagnose the anomalous heat balance on interdecadal timescales associated with heat storage changes observed from 1970-1988 in the expendable bathythermograph (XBT) data set. Given the smallness of the interdecadal signals compared to the El Niño-Southern Oscillation (ENSO) signal, the agreement between model and observations is remarkably good. The total anomalous heat balance is made up of two parts, the diabatic part (from the model temperature equation) and the adiabatic part (from the model mass conservation equation) due to thermocline heave. We therefore describe our analysis of both the total and diabatic anomalous heat balances in four areas of the tropical and subtropical North Pacific Ocean in the upper 400 m. The interdecadal total (diabatic plus adiabatic) heat balance in the North Pacific Ocean is characterized by a complicated interplay of different physical processes, especially revealed in basin-scale averages of the heat budget components that have comparable amounts of variance. In smaller subregions, simpler balances hold. For example, in the western equatorial Pacific (area 1) the total heat content tendency term is nearly zero, so that a simple balance exists between surface heat flux, vertical heat transport, and horizontal mixing. In the western subtropical Pacific the total heat content tendency balances the three-dimensional divergence of the heat flux. We speculate that this complexity is indicative of multiple physical mechanisms involved in the generation of North Pacific interdecadal variability. The diabatic heat balance north of 24°N, a region of special interest to The World Ocean Circulation Experiment (WOCE), can be simplified to a balance between the tendency term, surface heat flux, and meridional advection, the last term dominated by anomalous advection of mean temperature gradients. For the western equatorial region the diabatic heat content

  14. Residential fuelwood assessment, state of Minnesota, 2007-2008 heating season

    Science.gov (United States)

    Mimi Barzen; Ronald Piva; Chun Yi Wy; Rich. Dahlman

    2009-01-01

    During the spring and summer of 2008, the cooperating partners conducted a survey to determine the volume of residential fuelwood burned during the 2007-2008 heating season. Similar surveys were conducted for the 1960, 1969-1970, 1979-1980, 1984-1985, 1988-1989, 1995-1996, and 2002-2003 heating seasons. These surveys are part of a long-term effort to monitor trends in...

  15. Seasonal performance evaluation of electric air-to-water heat pump systems

    International Nuclear Information System (INIS)

    Dongellini, Matteo; Naldi, Claudia; Morini, Gian Luca

    2015-01-01

    A numerical model for the calculation of the seasonal performance of different kinds of electric air-to-water heat pumps is presented. The model is based on the procedure suggested by the European standard EN 14825 and the Italian standard UNI/TS 11300-4, which specify the guidelines for calculation of the seasonal performance of heat pumps during the heating season (SCOP), the cooling season (SEER) and for the production of domestic hot water. In order to consider the variation of outdoor conditions the developed model employs the bin-method. Different procedures are proposed in the paper for the analysis of the seasonal performance of mono-compressor, multi-compressor and variable speed compressor air-to-water heat pumps. The numerical results show the influence of the effective operating mode of the heat pumps on the SCOP value and put in evidence the impact of the design rules on the seasonal energy consumption of these devices. The study also highlights the importance of the correct sizing of the heat pump in order to obtain high seasonal efficiency and it shows that, for a fixed thermal load, inverter-driven and multi-compressor heat pumps have to be slightly oversized with respect to mono-compressor ones in order to obtain for the same building the highest SCOP values. - Highlights: • A model for the prediction of seasonal performance of HPs has been developed. • The model considers mono-compressor, multi-compressor and inverter-driven HPs. • The procedure takes into account HPs performances at partial load. • Optimization of heat pump sizing depending on its control system.

  16. High performance passive solar heating system with heat pipe energy transfer and latent heat storage

    NARCIS (Netherlands)

    Dijk, van H.A.L.; Galen, van E; Hensen, J.L.M.; Wit, de M.H.

    1983-01-01

    Preliminar results are reported from a current project on the development of a high performance passive solar heating system. Two special components are introduced: a. A heat pipe as a thermal diode tube for the efficient transfer of collected solar heat from the absorber plate to behind an

  17. Investigation of heat of fusion storage for solar low energy buildings

    DEFF Research Database (Denmark)

    Schultz, Jørgen Munthe; Furbo, Simon

    2005-01-01

    This paper describes a theoretical investigation by means of TRNSYS simulations of a partly heat loss free phase change material (PCM) storage solution for solar heating systems. The partly heat loss free storage is obtained by controlled used of super cooling in a mixture of sodium acetate...

  18. Modeling and Control of Heat Networks with Storage : the Single-Producer Multiple-Consumer Case

    NARCIS (Netherlands)

    Scholten, Tjeert Wobko; De Persis, Claudio; Tesi, Pietro

    2015-01-01

    In heat networks, energy storage is a viable approach to balance demand and supply. In such a network, a heat carrier is used in the form of water, where heat is injected and extracted through heat exchangers. The network can transport and store heated water in stratification tanks to shift loads in

  19. Modeling and control of heat networks with storage: The single-producer multiple-consumer case.

    NARCIS (Netherlands)

    Scholten, Tjardo; De Persis, Claudio; Tesi, Pietro

    2015-01-01

    In heat networks, energy storage is a viable approach to balance demand and supply. In such a network, a heat carrier is used in the form of water, where heat is injected and extracted through heat exchangers. The network can transport and store heated water in stratification tanks to shift loads in

  20. Effects of season and storage period on accumulation of individual carotenoids in pumpkin flesh (Cucurbita moschata).

    Science.gov (United States)

    Jaswir, Irwandi; Shahidan, Norshazila; Othman, Rashidi; Has-Yun Hashim, Yumi Zuhanis; Octavianti, Fitri; bin Salleh, Mohammad Noor

    2014-01-01

    Carotenoids are antioxidants with pharmaceutical potential. The major carotenoids important to humans are α-carotene, β-carotene, lycopene, lutein, zeaxanthin, and β-cryptoxanthin. Some of the biological functions and actions of these individual carotenoids are quite similar to each other, whereas others are specific. Besides genotype and location, other environmental effects such as temperature, light, mineral uptake, and pH have been found affect carotenoid development in plant tissues and organs. Therefore, this research investigated the effects of the season and storage periods during postharvest handling on the accumulation of carotenoid in pumpkin. This study shows that long-term storage of pumpkins resulted in the accumulation of lutein and β-carotene with a slight decrease in zeaxanthin. The amounts of β-carotene ranged from 174.583±2.105 mg/100g to 692.871±22.019 mg/100g, lutein from 19.841±9.693 mg/100g to 59.481±1.645 mg/100g, and zeaxanthin from not detected to 2.709±0.118 mg/100g. The pumpkins were collected three times in a year; they differed in that zeaxanthin was present only in the first season, while the amounts of β-carotene and lutein were the highest in the second and third seasons, respectively. By identifying the key factors among the postharvest handling conditions that control specific carotenoid accumulations, a greater understanding of how to enhance the nutritional values of pumpkin and other crops will be gained. Postharvest storage conditions can markedly enhance and influence the levels of zeaxanthin, lutein, and β-carotene in pumpkin. This study describes how the magnitudes of these effects depend on the storage period and season.

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

    International Nuclear Information System (INIS)

    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

  2. Effects of preincubation heating of broiler hatching eggs during storage, flock age, and length of storage period on hatchability.

    Science.gov (United States)

    Gucbilmez, M; Ozlü, S; Shiranjang, R; Elibol, O; Brake, J

    2013-12-01

    The effects of heating of eggs during storage, broiler breeder age, and length of egg storage on hatchability of fertile eggs were examined in this study. Eggs were collected from Ross 344 male × Ross 308 broiler breeders on paper flats, held overnight (1 d) at 18°C and 75% RH, and then transferred to plastic trays. In experiment 1, eggs were obtained at 28, 38, and 53 wk of flock age. During a further 10 d of storage, eggs either remained in the storage room (control) or were subjected to a heat treatment regimen of 26°C for 2 h, 37.8°C for 3 h, and 26°C for 2 h in a setter at d 5 of storage. In experiment 2, eggs from a flock at 28 wk of age were heated for 1 d of a 6-d storage period. Eggs from a 29-wk-old flock were either heated at d 1 or 5 of an 11-d storage period in experiment 3. In experiment 4, 27-wk-old flock eggs were heated twice at d 1 and 5 of an 11-d storage period. Control eggs stored for 6 or 11 d were coincubated as appropriate in each experiment. Heating eggs at d 5 of an 11-d storage period increased hatchability in experiment 1. Although no benefit of heating 28-wk-old flock eggs during 6 d of storage in experiment 2 was observed, heating eggs from a 29-wk-old flock at d 1 or 5 of an 11-d storage period increased hatchability in experiment 3. Further, heating eggs from a 27-wk-old flock twice during 11 d of storage increased hatchability in experiment 4. These effects were probably due to the fact that eggs from younger flocks had been reported to have many embryos at a stage of development where the hypoblast had not yet fully developed (less than EG-K12 to EG-K13), such that heating during extended storage advanced these embryos to a more resistant stage.

  3. Experimental and numerical study of latent heat thermal energy storage systems assisted by heat pipes for concentrated solar power application

    Science.gov (United States)

    Tiari, Saeed

    A desirable feature of concentrated solar power (CSP) with integrated thermal energy storage (TES) unit is to provide electricity in a dispatchable manner during cloud transient and non-daylight hours. Latent heat thermal energy storage (LHTES) offers many advantages such as higher energy storage density, wider range of operating temperature and nearly isothermal heat transfer relative to sensible heat thermal energy storage (SHTES), which is the current standard for trough and tower CSP systems. Despite the advantages mentioned above, LHTES systems performance is often limited by low thermal conductivity of commonly used, low cost phase change materials (PCMs). Research and development of passive heat transfer devices, such as heat pipes (HPs) to enhance the heat transfer in the PCM has received considerable attention. Due to its high effective thermal conductivity, heat pipe can transport large amounts of heat with relatively small temperature difference. The objective of this research is to study the charging and discharging processes of heat pipe-assisted LHTES systems using computational fluid dynamics (CFD) and experimental testing to develop a method for more efficient energy storage system design. The results revealed that the heat pipe network configurations and the quantities of heat pipes integrated in a thermal energy storage system have a profound effect on the thermal response of the system. The optimal placement of heat pipes in the system can significantly enhance the thermal performance. It was also found that the inclusion of natural convection heat transfer in the CFD simulation of the system is necessary to have a realistic prediction of a latent heat thermal storage system performance. In addition, the effects of geometrical features and quantity of fins attached to the HPs have been studied.

  4. Thermal diffusivity measurement of erythritol and numerical analysis of heat storage performance on a fin-type heat exchanger

    International Nuclear Information System (INIS)

    Zamengo, Massimiliano; Funada, Tomohiro; Morikawa, Junko

    2017-01-01

    Highlights: • Thermal diffusivity of Erythritol was measured by temperature wave method. • Thermal diffusivity was measured in function of temperature and during phase change. • Database of temperature-dependent thermal properties is used for numerical analysis. • Heat transfer and heat storage were analyzed in a fin-type heat exchanger. • Use of temperature-dependent properties in calculations lead to longer melting time. - Abstract: Temperature dependency of thermal diffusivity of erythritol was measured by temperature wave analysis (TWA) method. This modulating technique allowed measuring thermal diffusivity continuously, even during the phase transition solid-liquid. Together with specific heat capacity and specific enthalpy measured by differential scanning calorimetry, the values of measured properties were utilized in a bi-dimensional numerical model for analysis of heat transfer and heat storage performance. The geometry of the model is representative of a cross section of a fin-type heat exchanger, in which erythritol is filling the interspaces between fins. Time-dependent temperature change and heat storage performance were analyzed by considering the variation of thermophysical properties as a function of temperature. The numerical method can be utilized for a fast parametric analysis of heat transfer and heat storage performance into heat storage systems of phase-change materials and composites.

  5. Initial Development of a Combined PCM and TABS Solution for Heat Storage and Cooling

    DEFF Research Database (Denmark)

    Pomianowski, Michal Zbigniew; Heiselberg, Per; Jensen, Rasmus Lund

    2011-01-01

    to their significant thermal energy storage capabilities. The TABS has a potential for increasing the exploitation of the thermal mass of the building, which is rarely exposed for heat transfer.The main objective of this study is to optimize the location and amount of PCM in a hollow core deck in order to optimize...... heat storage capacity. A series of simulations were conducted using the COMSOL program to obtain knowledge regarding the dynamic heat storage capacity of the investigated hollow core deck element as a function of the amount and location of PCM. Furthermore, the dynamic heat storage capacity...

  6. Patterns of Seasonal Heat Uptake and Release Over the Arctic Ocean Between 1979-2016

    Science.gov (United States)

    Helmberger, M. N.; Serreze, M. C.

    2017-12-01

    As the Arctic Ocean loses its sea ice cover, there is a stronger oceanic heat gain from the surface fluxes throughout the spring and summer; ultimately meaning that there is more energy to transfer out of the ocean to the atmosphere and outer space in the autumn and winter. Recent work has shown that the increased oceanic heat content at the end of summer in turn delays autumn ice growth, with implications for marine shipping and other economic activities. Some of the autumn and winter heat loss to the atmosphere is represented by evaporation, which increases the atmospheric water vapor content, and there is growing evidence that this is contributing to increases in regional precipitation. However, depending on patterns of seasonal sea ice retreat and weather conditions, the spring-summer heat uptake and autumn-winter heat loss can be highly variable from year to year and regionally. Here, we examine how the seasonality in upper ocean heat uptake and release has evolved over the past 37 years and the relationships between this seasonal heat gain and loss and the evolution of sea ice cover. We determine which regions have seen the largest increases in total seasonal heat uptake and how variable this uptake can be. Has the timing at which the Arctic Ocean (either as a whole or by region) transitions from an atmospheric energy sink to an atmospheric energy source (or from a source to a sink) appreciably changed? What changes have been observed in the seasonal rates of seasonal heat uptake and release? To begin answering these questions, use is made of surface fluxes from the ERA-Interim reanalysis and satellite-derived sea ice extent spanning the period 1979 through the present. Results from ERA-Interim will be compared to those from other reanalyses and satellite-derived flux estimates.

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

    Energy Technology Data Exchange (ETDEWEB)

    Sanner, B. [Justus Liebig University, Giessen (Germany). Institute of Applied Geosciences; Karytsas, C.; Mendrinos, D. [Center for Renewable Energy Sources, Pikermi (Greece); Rybach, L. [Geowatt AG, Zurich (Switzerland)

    2003-12-01

    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 transfers the heat from the earth to the evaporator of the heat pump, thus utilising geothermal energy. In cooling mode, they use the earth as a heat sink. With Borehole Heat Exchangers (BHE), geothermal heat pumps can offer both heating and cooling at virtually any location, with great flexibility to meet any demands. More than 20 years of R and D focusing on BUE in Europe has resulted in a well-established concept of sustainability for this technology, as well as sound design and installation criteria. Recent developments are the Thermal Response Test, which allows in-situ-determination of ground thermal properties for design purposes, and thermally enhanced grouting materials to reduce borehole thermal resistance. For cooling purposes, but also for the storage of solar or waste heat, the concept of underground thermal energy storage (UTES) could prove successful. Systems can be either open (aquifer storage) or can use BHE (borehole storage). Whereas cold storage is already established on the market, heat storage, and, in particular, high temperature heat storage (> 50{sup o}C) is still in the demonstration phase. Despite the fact that geothermal heat pumps have been in use for over 50 years now (the first were in the USA), market penetration of this technology is still in its infancy, with fossil fuels dominating the space heating market and air-to-air heat pumps that of space cooling. In Germany, Switzerland, Austria, Sweden, Denmark, Norway, France and the USA, large numbers of geothermal heat pumps are already operational, and installation guidelines, quality control and contractor certification are now major issues

  8. Seasonal and annual heat budgets offshore the Hanko Peninsula, Gulf of Finland

    Energy Technology Data Exchange (ETDEWEB)

    Merkouriadi, I.; Lepparanta, M. [Helsinki Univ. (Finland). Dept. of Physics], Email: ioanna.merkouriadi@helsinki.fi; Shirasawa, K. [Hokkaido Univ., Sapporo (Japan). Pan-Okhotsk Research Center, Inst. of Low Temperature Science

    2013-06-01

    A joint Finnish-Japanese sea-ice experiment 'Hanko-9012' carried out offshore the Hanko Peninsula included seasonal monitoring and intensive field campaigns. Ice, oceanographic and meteorological data were collected to examine the structure and properties of the Baltic Sea brackish ice, heat budget and solar radiation transfer through the ice cover. Here, the data from two years (2000 and 2001) are used for the estimation of the seasonal and annual heat budgets. Results present the surface heat balance, and the heat budget of the ice sheet and the waterbody. The ice cover acted as a good control measure of the net surface heat exchange. Solar radiation had a strong seasonal cycle with a monthly maximum at 160 and a minimum below 10 W m{sup -2}, while net terrestrial radiation was mostly between -40 and -60 W m{sup -2}. Latent heat exchange was much more important than sensible heat exchange, similar the net terrestrial radiation values in summer and autumn. A comparison between the latent heat flux released or absorbed by the ice and the net surface heat fluxes showed similar patterns, with a clearly better fit in 2001. The differences can be partly explained by the oceanic heat flux to the lower ice boundary. (orig.)

  9. Sydlangeland Fjernvarme A.m.b.a. Feasibility study on 10-20.000 m{sup 3} pond heat storage[Denmark]; Sydlangeland Fjernvarme A.m.b.a. Forundersoegelse for 10-20.000 m{sup 3} damvarmelager

    Energy Technology Data Exchange (ETDEWEB)

    Visbjerg, L. [Sydlangeland Fjernvarme A.m.b.a. (Denmark); Wesenberg, C.; Bliksted, T. [NIRAS Raadgivende Ingenioerer og Planlaeggere A/S (Denmark); Porsvig, M. [Geoteknisk Institut (Denmark); Duer, K. [DTU, Solenergi Center Danmark (Denmark)

    2000-11-01

    The project includes siting analyses, geotechnical feasibility studies and evaluations of operating economy for establishing a seasonal heat storage carried out as a 10-20,000 m{sup 3} pilot pond heat storage at Sydlangeland straw-fired district heating plant. (EHS)

  10. Steam-based charging-discharging of a PCM heat storage | Tesfay ...

    African Journals Online (AJOL)

    ... the intermittent solar energy for continuous and near isothermal applications. ... The storage has the capacity of storing up to 250ºC heat and supply this heat ... which includes bread baking, kita (large pancake) baking and water boiling.

  11. Applications of thermal energy storage to waste heat recovery in the food processing industry

    Science.gov (United States)

    Wojnar, F.; Lunberg, W. L.

    1980-01-01

    A study to assess the potential for waste heat recovery in the food industry and to evaluate prospective waste heat recovery system concepts employing thermal energy storage was conducted. The study found that the recovery of waste heat in canning facilities can be performed in significant quantities using systems involving thermal energy storage that are both practical and economical. A demonstration project is proposed to determine actual waste heat recovery costs and benefits and to encourage system implementation by the food industry.

  12. Experimental analysis of a direct expansion solar assisted heat pump with integral storage tank for domestic water heating under zero solar radiation conditions

    International Nuclear Information System (INIS)

    Fernández-Seara, José; Piñeiro, Carolina; Alberto Dopazo, J.; Fernandes, F.; Sousa, Paulo X.B.

    2012-01-01

    Highlights: ► We analyze a direct expansion solar assisted heat pump under zero solar radiation. ► We determine the COP and equivalent seasonal performance factors (SPFe). ► We determine the main components’ performance under transient operating conditions. ► The Huang and Lee performance evaluation method provides a characteristic COP of 3.23. - Abstract: This paper deals with the experimental evaluation of the performance of a direct expansion solar assisted heat pump water heating (DX-SAHPWH) system working under zero solar radiation conditions at static heating operation mode of the storage tank. The DX-SAHPWH system includes two bare solar collectors as evaporator, a R134a rotary-type hermetic compressor, a thermostatic expansion valve and a helical coil condenser immersed in a 300 L water storage tank. The zero solar radiation and stable ambient air temperature working conditions were established by placing the solar collectors into a climate chamber. The analysis is based on experimental data taken from the DX-SAHPWH provided by the manufacturer and equipped with an appropriate data acquisition system. In the paper, the experimental facility, the data acquisition system and the experimental methodology are described. Performance parameters to evaluate the energy efficiency, such as COP and equivalent seasonal performance factors (SPFe) for the heating period, and the water thermal stratification in the storage tank are defined and obtained from the experimental data. Results from the experimental analysis under transient operating working conditions of the DX-SAHPWH system and its main components are shown and discussed. Lastly, the Huang and Lee DX-SAHPWH performance evaluation method was applied resulting in a characteristic COP of 3.23 for the DX-SAHPWH system evaluated under zero solar radiation condition.

  13. Heat of fusion storage systems for combined solar systems in low energy buildings

    DEFF Research Database (Denmark)

    Schultz, Jørgen Munthe; Furbo, Simon

    2004-01-01

    Solar heating systems for combined domestic hot water and space heating has a large potential especially in low energy houses where it is possible to take full advantage of low temperature heating systems. If a building integrated heating system is used – e.g. floor heating - the supply temperature...... from solid to liquid form (Fig. 1). Keeping the temperature as low as possible is an efficient way to reduce the heat loss from the storage. Furthermore, the PCM storage might be smaller than the equivalent water storage as more energy can be stored per volume. If the PCM further has the possibility...... systems through further improvement of water based storages and in parallel to investigate the potential of using storage designs with phase change materials, PCM. The advantage of phase change materials is that large amounts of energy can be stored without temperature increase when the material is going...

  14. Implementation of heat production and storage technology and devices in power systems

    International Nuclear Information System (INIS)

    Romanovsky, G.; Mutale, J.

    2012-01-01

    Implementation of heat storage devices and technologies at power generation plants is a promising way to provide more efficient use of natural energy resources. Heat storage devices can partly replace conventional heating technologies (such as direct use of fossil fuels) during peak energy demand or in the situations where heat and electricity supply and demand do not coincide and to obtain low cost heat energy which can be further transmitted to industrial, commercial and domestic consumers. This paper presents the innovative Heat Production and Storage Device and its application at conventional, nuclear and renewable power generation plants for optimization and balancing of electricity grids. The Heat Production and Storage Device is a vessel type induction-immersion heat production and storage device which produces pre-heated water under pressure for heat energy conservation. Operation of this device is based on simultaneous and/or sequential action of an inductor and an immersion heater and can be easily connected to the electricity network as a single or a three phase unit. Heat energy accumulated by the Heat Production and Storage Device can be utilized in different industrial technological processes during periods of high energy prices. - Highlights: ► Heat Production and Storage Device for energy conservation within low load hours. ► Simultaneous and/or sequential operation of the inductor and immersion heater. ► Transform the energy of low frequency electrical current (50 Hz) into heat energy. ► Connection to the electricity network either in single or three phase unit. ► Heat Production and Storage Device will enhance the economic value of the system.

  15. A review of chemical heat pumps, thermodynamic cycles and thermal energy storage technologies for low grade heat utilisation

    International Nuclear Information System (INIS)

    Chan, C.W.; Ling-Chin, J.; Roskilly, A.P.

    2013-01-01

    A major cause of energy inefficiency is a result of the generation of waste heat and the lack of suitable technologies for cost-effective utilisation of low grade heat in particular. The market potential for surplus/waste heat from industrial processes in the UK is between 10 TWh and 40 TWh, representing a significant potential resource which has remained unexploited to date. This paper reviews selected technologies suitable for utilisation of waste heat energy, with specific focus on low grade heat, including: (i) chemical heat pumps, such as adsorption and absorption cycles for cooling and heating; (ii) thermodynamic cycles, such as the organic Rankine cycle (ORC), the supercritical Rankine cycle (SRC) and the trilateral cycle (TLC), to produce electricity, with further focus on expander and zeotropic mixtures, and (iii) thermal energy storage, including sensible and latent thermal energy storages and their corresponding media to improve the performance of low grade heat energy systems. - Highlights: ► The review of various thermal technologies for the utilisation of under exploited low grade heat. ► The analyses of the absorption and adsorption heat pumps possibly with performance enhancement additives. ► The analyses of thermal energy storage technologies (latent and sensible) for heat storage. ► The analyses of low temperature thermodynamic cycles to maximise power production.

  16. Seasonal carbon storage and growth in Mediterranean tree seedlings under different water conditions.

    Science.gov (United States)

    Sanz-Pérez, Virginia; Castro-Díez, Pilar; Joffre, Richard

    2009-09-01

    In all Mediterranean-type ecosystems, evergreen and deciduous trees differing in wood anatomy, growth pattern and leaf habit coexist, suggesting distinct adaptative responses to environmental constraints. This study examined the effects of summer water stress on carbon (C) storage and growth in seedlings of three coexisting Mediterranean trees that differed in phenology and wood anatomy characteristics: Quercus ilex subsp. ballota (Desf.) Samp., Quercus faginea Lam. and Pinus halepensis L. Seedlings were subjected to two levels of watering during two consecutive summers and achieved a minimum of -0.5 and -2.5 MPa of predawn water potential in the control and water stress treatment, respectively. Both Quercus species concentrated their growth in the early growing season, demanding higher C in early spring but replenishing C-stores in autumn. These species allocated more biomass to roots, having larger belowground starch and lipid reserves. Quercus species differed in seasonal storage dynamics from P. halepensis. This species allocated most of its C to aboveground growth, which occurred gradually during the growing season, leading to fewer C-reserves. Soluble sugar and starch concentrations sharply declined in August in P. halepensis, probably because reserves support respiration demands as this species closed stomata earlier under water stress. Drought reduced growth of the three species, mainly in Q. faginea and P. halepensis, but not C-reserves, suggesting that growth under water stress conditions is not limited by C-availability.

  17. The energy efficiency ratio of heat storage in one shell-and-one tube phase change thermal energy storage unit

    International Nuclear Information System (INIS)

    Wang, Wei-Wei; Wang, Liang-Bi; He, Ya-Ling

    2015-01-01

    Highlights: • A parameter to indicate the energy efficiency ratio of PCTES units is defined. • The characteristics of the energy efficiency ratio of PCTES units are reported. • A combined parameter of the physical properties of the working mediums is found. • Some implications of the energy efficiency ratio in design of PCTES units are analyzed. - Abstract: From aspect of energy consuming to pump heat transfer fluid, there is no sound basis on which to create an optimum design of a thermal energy storage unit. Thus, it is necessary to develop a parameter to indicate the energy efficiency of such unit. This paper firstly defines a parameter that indicates the ratio of heat storage of phase change thermal energy storage unit to energy consumed in pumping heat transfer fluid, which is called the energy efficiency ratio, then numerically investigates the characteristics of this parameter. The results show that the energy efficiency ratio can clearly indicate the energy efficiency of a phase change thermal energy storage unit. When the fluid flow of a heat transfer fluid is in a laminar state, the energy efficiency ratio is larger than in a turbulent state. The energy efficiency ratio of a shell-and-tube phase change thermal energy storage unit is more sensitive to the outer tube diameter. Under the same working conditions, within the heat transfer fluids studied, the heat storage property of the phase change thermal energy storage unit is best for water as heat transfer fluid. A combined parameter is found to indicate the effects of both the physical properties of phase change material and heat transfer fluid on the energy efficiency ratio

  18. Enhanced Thermal Management System for Spent Nuclear Fuel Dry Storage Canister with Hybrid Heat Pipes

    International Nuclear Information System (INIS)

    Jeong, Yeong Shin; Bang, In Cheol

    2016-01-01

    Dry storage uses the gas or air as coolant within sealed canister with neutron shielding materials. Dry storage system for spent fuel is regarded as relatively safe and emits little radioactive waste for the storage, but it showed that the storage capacity and overall safety of dry cask needs to be enhanced for the dry storage cask for LWR in Korea. For safety enhancement of dry cask, previous studies of our group firstly suggested the passive cooling system with heat pipes for LWR spent fuel dry storage metal cask. As an extension, enhanced thermal management systems for the spent fuel dry storage cask for LWR was suggested with hybrid heat pipe concept, and their performances were analyzed in thermal-hydraulic viewpoint in this paper. In this paper, hybrid heat pipe concept for dry storage cask is suggested for thermal management to enhance safety margin. Although current design of dry cask satisfies the design criteria, it cannot be assured to have long term storage period and designed lifetime. Introducing hybrid heat pipe concept to dry storage cask designed without disrupting structural integrity, it can enhance the overall safety characteristics with adequate thermal management to reduce overall temperature as well as criticality control. To evaluate thermal performance of hybrid heat pipe according to its design, CFD simulation was conducted and previous and revised design of hybrid heat pipe was compared in terms of temperature inside canister

  19. Effectiveness of solar heating systems for the regeneration of adsorbents in recessed fruit and vegetable storages

    International Nuclear Information System (INIS)

    Khuzhakulov, S.M.; Uzakov, G.N.; Vardiyashvili, A.B

    2013-01-01

    A new method for the regeneration of adsorbents using solar heating systems is proposed. It provides energy saving through the control of the gas composition and humidity in recessed fruit and vegetable storages. The effectiveness of solar heating systems, such as a 'hot box' for the regeneration of adsorbents in fruit and vegetable storages is shown. (author)

  20. Mobile heat storage containers and their transport by rail or road

    Energy Technology Data Exchange (ETDEWEB)

    Goldenberg, Philipp

    2013-10-15

    Mobile heat storage containers are capable of making a contribution to the meaningful use of energy which is needed for use at a location other than where it originates. The study presented in this report outlines the technology of mobile heat storage and analyses an example of its transport by rail or road. (orig.)

  1. Comparison of temperature estimates from heat transport model and electrical resistivity tomography during a shallow heat injection and storage experiment

    OpenAIRE

    Hermans, Thomas; Daoudi, Moubarak; Vandenbohede, Alexander; Robert, Tanguy; Caterina, David; Nguyen, Frédéric

    2012-01-01

    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. Geophysical methods may be useful in order to yield additional information with greater coverage than conventional wells. We report a heat transport study during a shallow heat injection and storage field test. Heated water (about 50°C) was injected for 6 days at the rate of 80 l...

  2. Seasonal changes in the atmospheric heat balance simulated by the GISS general circulation model

    Science.gov (United States)

    Stone, P. H.; Chow, S.; Helfand, H. M.; Quirk, W. J.; Somerville, R. C. J.

    1975-01-01

    Tests of the ability of numerical general circulation models to simulate the atmosphere have focussed so far on simulations of the January climatology. These models generally present boundary conditions such as sea surface temperature, but this does not prevent testing their ability to simulate seasonal changes in atmospheric processes that accompany presented seasonal changes in boundary conditions. Experiments to simulate changes in the zonally averaged heat balance are discussed since many simplified models of climatic processes are based solely on this balance.

  3. Possible application of dam lake as a seasonal solar energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Wakabayshi, Hiroaki; Murata, Hideto; Nishijima, Keiichi [Kanazawa Inst. of Technology, Dep. of Managerial Engineering, Ishikawa (Japan)

    1996-12-31

    For promoting efficient use of energy, a new concept is required that society can choose to make a positive approach toward a solar energy based rural community which maximizes harmony with nature. This basic concept uses a water lake as a thermal energy storage. Thermocline measurements were made at the Uchikawa Dam Lake located in Kanazawa, Ishikawa, Japan to evaluate several kind of exergy contents as a new energy supply potential. The data indicated that the system could be developed with full potential as a seasonal energy storage to be used for mostly regional cooling. This concept seems interesting to invite internationally an energy efficient society to be employed in LDCs as well as in developed countries. (author) 12 figs., 2 tabs., 7 refs.

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

    Science.gov (United States)

    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.

  5. Quantifying demand flexibility of power-to-heat and thermal energy storage in the control of building heating systems

    DEFF Research Database (Denmark)

    Finck, Christian; Li, Rongling; Kramer, Rick

    2018-01-01

    restricted by power-to-heat conversion such as heat pumps and thermal energy storage possibilities of a building. To quantify building demand flexibility, it is essential to capture the dynamic response of the building energy system with thermal energy storage. To identify the maximum flexibility a building......’s energy system can provide, optimal control is required. In this paper, optimal control serves to determine in detail demand flexibility of an office building equipped with heat pump, electric heater, and thermal energy storage tanks. The demand flexibility is quantified using different performance...... of TES and power-to-heat in any case of charging, discharging or idle mode. A simulation case study is performed showing that a water tank, a phase change material tank, and a thermochemical material tank integrated with building heating system can be designed to provide flexibility with optimal control....

  6. Thermal energy storage systems using fluidized bed heat exchangers

    Science.gov (United States)

    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.

  7. Experimental evaluation on natural convection heat transfer of microencapsulated phase change materials slurry in a rectangular heat storage tank

    International Nuclear Information System (INIS)

    Zhang Yanlai; Rao Zhonghao; Wang Shuangfeng; Zhang Zhao; Li Xiuping

    2012-01-01

    Highlights: ► It gives heat transfer characteristics in a rectangular heat storage tank as the basic unit for reservoir of thermal storage. ► Onset of natural convection gets easier for the MPCMS with a higher mass concentration. ► It enhances the heat transfer ability of natural convection for the MPCMS. ► Obtained the relationship between Ra and Nu of the MPCMS. - Abstract: The main purpose of this experiment is to evaluate natural convection heat transfer characteristics of microencapsulated PCM (phase change material) slurry (MPCMS) during phase change process in a rectangular heat storage tank heated from the bottom and cooled at the top. The microencapsulated PCM is several material compositions of n-paraffin waxes (mainly nonadecane) as the core materials, outside a layer of a melamine resin wrapped. In the present study, its slurry is used mixing with water. And the specific heat capacity with latent heat shows a peak value at the temperature of about T = 31 °C. We investigate the influences of the phase change process of the MPCMS on natural convection heat transfer. The experimental results indicate that phase change process of the MPCMS promote natural convection heat transfer. The local maximum heat transfer enhancement occurs at approximately T H = 34 °C corresponding to the heated plate temperature. With high mass concentration C m , the onset of natural convection gets easier for the MPCMS. The temperature gradient is larger near top plate and bottom plate of a rectangular heat storage tank. Heat transfer coefficient increases with the phase change of the PCM. And it summarizes that the phase change process of the PCM promote the occurrence of natural convection.

  8. Microscale Enhancement of Heat and Mass Transfer for Hydrogen Energy Storage

    Energy Technology Data Exchange (ETDEWEB)

    Drost, Kevin [Oregon State Univ., Corvallis, OR (United States); Jovanovic, Goran [Oregon State Univ., Corvallis, OR (United States); Paul, Brian [Oregon State Univ., Corvallis, OR (United States)

    2015-09-30

    The document summarized the technical progress associated with OSU’s involvement in the Hydrogen Storage Engineering Center of Excellence. OSU focused on the development of microscale enhancement technologies for improving heat and mass transfer in automotive hydrogen storage systems. OSU’s key contributions included the development of an extremely compact microchannel combustion system for discharging hydrogen storage systems and a thermal management system for adsorption based hydrogen storage using microchannel cooling (the Modular Adsorption Tank Insert or MATI).

  9. Hybrid heat pipe based passive cooling device for spent nuclear fuel dry storage cask

    International Nuclear Information System (INIS)

    Jeong, Yeong Shin; Bang, In Cheol

    2016-01-01

    Highlights: • Hybrid heat pipe was presented as a passive cooling device for dry storage cask of SNF. • A method to utilize waste heat from spent fuel was suggested using hybrid heat pipe. • CFD analysis was performed to evaluate the thermal performance of hybrid heat pipe. • Hybrid heat pipe can increase safety margin and storage capacity of the dry storage cask. - Abstract: Conventional dry storage facilities for spent nuclear fuel (SNF) were designed to remove decay heat through the natural convection of air, but this method has limited cooling capacity and a possible re-criticality accident in case of flooding. To enhance the safety and capacity of dry storage cask of SNF, hybrid heat pipe-based passive cooling device was suggested. Heat pipe is an excellent passive heat transfer device using the principles of both conduction and phase change of the working fluid. The heat pipe containing neutron absorber material, the so-called hybrid heat pipe, is expected to prevent the re-criticality accidents of SNF and to increase the safety margin during interim and long term storage period. Moreover, a hybrid heat pipe with thermoelectric module, a Stirling engine and a phase change material tank can be used for utilization of the waste heat as heat-transfer medium. Located at the guide tube or instrumentation tube, hybrid heat pipe can remove decay heat from inside the sealed metal cask to outside, decreasing fuel rod temperature. In this paper, a 2-step analysis was performed using computational fluid dynamics code to evaluate the heat and fluid flow inside a cask, which consisted of a single spent fuel assembly simulation and a full-scope dry cask simulation. For a normal dry storage cask, the maximum fuel temperature is 290.0 °C. With hybrid heat pipe cooling, the temperature decreased to 261.6 °C with application of one hybrid heat pipe per assembly, and to 195.1 °C with the application of five hybrid heat pipes per assembly. Therefore, a dry

  10. Physical properties and heat transfer characteristics of materials for krypton-85 storage

    International Nuclear Information System (INIS)

    Christensen, A.B.

    1977-09-01

    Krypton-85 decay results in heat generation, and the subsequent temperature increase in the krypton-85 storage media must be evaluated. This report compiles the physical properties of krypton and of potential krypton-85 storage materials which are required to calculate the maximum temperature developed during storage. Temperature calculations were made for krypton-85 stored as a gas or immobilized solid in steel storage cylinders. The effects of krypton-85 loading, cylinder radius, storage media properties, and exterior cooling on storage temperature were shown

  11. Experimental and numerical investigation of a scalable modular geothermal heat storage system

    Science.gov (United States)

    Nordbeck, Johannes; Bauer, Sebastian; Beyer, Christof

    2017-04-01

    Storage of heat will play a significant role in the transition towards a reliable and renewable power supply, as it offers a way to store energy from fluctuating and weather dependent energy sources like solar or wind power and thus better meet consumer demands. The focus of this study is the simulation-based design of a heat storage system, featuring a scalable and modular setup that can be integrated with new as well as existing buildings. For this, the system can be either installed in a cellar or directly in the ground. Heat supply is by solar collectors, and heat storage is intended at temperatures up to about 90°C, which requires a verification of the methods used for numerical simulation of such systems. One module of the heat storage system consists of a helical heat exchanger in a fully water saturated, high porosity cement matrix, which represents the heat storage medium. A lab-scale storage prototype of 1 m3 volume was set up in a thermally insulated cylinder equipped with temperature and moisture sensors as well as flux meters and temperature sensors at the inlet and outlet pipes in order to experimentally analyze the performance of the storage system. Furthermore, the experimental data was used to validate an accurate and spatially detailed high-resolution 3D numerical model of heat and fluid flow, which was developed for system design optimization with respect to storage efficiency and environmental impacts. Three experiments conducted so far are reported and analyzed in this work. The first experiment, consisting of cooling of the fully loaded heat storage by heat loss across the insulation, is designed to determine the heat loss and the insulation parameters, i.e. heat conductivity and heat capacity of the insulation, via inverse modelling of the cooling period. The average cooling rate experimentally found is 1.2 °C per day. The second experiment consisted of six days of thermal loading up to a storage temperature of 60°C followed by four days

  12. Serso - Seasonal storage of solar energy for the de-icing of a bridge; Serso, stockage saisonnier solaire pour le degivrage d'un pont

    Energy Technology Data Exchange (ETDEWEB)

    Pahud, D.

    2007-07-01

    This report for the Swiss Federal Office of Energy (SFOE) takes a look at a project that uses stored solar heat to de-ice a bridge. A concept is described which involves seasonal heat storage in the ground. Solar energy is collected during the summer, stored in the ground with the help of a borehole heat exchanger field, and recovered in winter for use in the defrosting of the bridge. Measurements of the system's thermal performance over a few years have been used to develop and validate a simulation tool for the sizing of similar systems. This simulation tool, called BRIDGESIM, is described and the various parameters used for particular situations are discussed. The effects of various factors such as the presence of ground water are discussed.

  13. Application of latent heat storage devices and thermal solar collectors; Einsatz von Latentwaermespeichern und Solarthermie

    Energy Technology Data Exchange (ETDEWEB)

    Leonhardt, Corinna; Mueller, Dirk [RWTH Aachen, E.ON Energieforschungszentrum, Lehrstuhl fuer Gebaeude- und Raumklimatechnik (Germany)

    2010-12-15

    Modern heating systems for buildings need a supply temperature of approximately 35 C. In this temperature range it is possible to use low temperature storage systems. Therefore the heat losses over the envelope can be reduced because of the smaller temperature difference between the ambient air and the storage. In order to use the existing technique of the buffer storages more efficiently, latent heat storage devices are put into the storage volume. For the operating temperature range of 30 to 40 C paraffins or salt hydrates can be used. Because of the low operating temperature it is possible to integrate solar thermal systems in the heating system (especially in spring and autumn). The overall system performance will be analysed. (Copyright copyright 2010 Ernst and Sohn Verlag fuer Architektur und technische Wissenschaften GmbH and Co. KG, Berlin)

  14. Evaporation of liquefied natural gas in conditions of compact storage containers heating

    Science.gov (United States)

    Telgozhayeva, D. S.

    2014-08-01

    Identical by its power, but located in different parts of the external surface of the tank, the heating sources are different intensity heat transfer modes is heating up, respectively, times of vapour pressure rise to critical values. Developed mathematical model and method of calculation can be used in the analysis of conditions of storage tanks for liquefied gases.

  15. Operation of heat pumps for smart grid integrated buildings with thermal energy storage

    NARCIS (Netherlands)

    Finck, C.J.; Li, R.; Zeiler, W.

    2017-01-01

    A small scale office building consisting of radiant heating, a heat pump, and a water thermal energy storage tank is implemented in an optimal control framework. The optimal control aims to minimize operational electricity costs of the heat pump based on real-time power spot market prices. Optimal

  16. Thermochemical Storage of Middle Temperature Wasted Heat by Functionalized C/Mg(OH2 Hybrid Materials

    Directory of Open Access Journals (Sweden)

    Emanuela Mastronardo

    2017-01-01

    Full Text Available For the thermochemical performance implementation of Mg(OH2 as a heat storage medium, several hybrid materials have been investigated. For this study, high-performance hybrid materials have been developed by exploiting the authors’ previous findings. Expanded graphite (EG/carbon nanotubes (CNTs-Mg(OH2 hybrid materials have been prepared through Mg(OH2 deposition-precipitation over functionalized, i.e., oxidized, or un-functionalized EG or CNTs. The heat storage performances of the carbon-based hybrid materials have been investigated through a laboratory-scale experimental simulation of the heat storage/release cycles, carried out by a thermogravimetric apparatus. This study offers a critical evaluation of the thermochemical performances of developed materials through their comparison in terms of heat storage and output capacities per mass and volume unit. It was demonstrated that both EG and CNTs improves the thermochemical performances of the storage medium in terms of reaction rate and conversion with respect to pure Mg(OH2. With functionalized EG/CNTs-Mg(OH2, (i the potential heat storage and output capacities per mass unit of Mg(OH2 have been completely exploited; and (ii higher heat storage and output capacities per volume unit were obtained. That means, for technological applications, as smaller volume at equal stored/released heat.

  17. Wind power integration with heat pumps, heat storages, and electric vehicles – Energy systems analysis and modelling

    DEFF Research Database (Denmark)

    Hedegaard, Karsten

    The fluctuating and only partly predictable nature of wind challenges an effective integration of large wind power penetrations. This PhD thesis investigates to which extent heat pumps, heat storages, and electric vehicles can support the integration of wind power. Considering the gaps in existing...... in an energy system context. Energy systems analyses reveal that the heat pumps can even without flexible operation contribute significantly to facilitating larger wind power investments and reducing system costs, fuel consumption, and CO2 emissions. When equipping the heat pumps with heat storages, only...... moderate additional benefits are achieved. Hereof, the main benefit is that the need for investing in peak/reserve capacities can be reduced through peak load shaving. It is more important to ensure flexible operation of electric vehicles than of individual heat pumps, due to differences in the load...

  18. An experimental study on the heat transfer characteristics of a heat pipe heat exchanger with latent heat storage. Part II: Simultaneous charging/discharging modes

    International Nuclear Information System (INIS)

    Liu Zhongliang; Wang Zengyi; Ma Chongfang

    2006-01-01

    In this part of the paper, the performance of the simultaneous charging/discharging operation modes of the heat pipe heat exchanger with latent heat storage is experimentally studied. The experimental results show that the device may operate under either the fluid to fluid heat transfer with charging heat to the phase change material (PCM) or the fluid to fluid heat transfer with discharging heat from the PCM modes according to the initial temperature of the PCM. The melting/solidification curves, the performances of the heat pipes and the device, the influences of the inlet temperature and the mass flow rate of the cold water on the operation performance are investigated by extensive experiments. The experimental results also disclose that under the simultaneous charging/discharging operation mode, although the heat transfer from the hot water directly to the cold water may vary, it always takes up a major part of the total heat recovered by the cold water due to the very small thermal resistance compared with the thermal resistance of the PCM side. The melting/solidification processes taking place in the simultaneous charging/discharging operation are compared with those in the charging only and discharging only processes. By applying a simplified thermal resistance analysis, a criterion for predicting the exact operation modes was derived and used to explain the observed experimental phenomena

  19. SOME FEATURES OF THE POWER SUPPLY OF RESIDENTIAL BUILDINGS DURING THE HEATING SEASON

    Directory of Open Access Journals (Sweden)

    S. N. Osipov

    2017-01-01

    Full Text Available A large proportion of consumption of different types of energy by the residential sector, especially in the heating period, makes the energy efficiency of buildings without considering the loss of fuel with a significant reduction in hourly load on the generators, especially at night, already insufficient for real energy savings. Therefore in Belarus, in order to attract the consumer, electricity tariff for heating at night hours (from 11 p.m. to 6.00 a.m. is three times cheaper than at any other time. Significant increase of the electricity consumption of at night could be achieved by using heat accumulators for heating and hot water supply to the residential sector. Particularly effective are water accumulators of heat and accumulators of underfloor heating that enable to use a coolant with a temperature of 40 оC and to increase the useful supply of heat. The use of heat accumulators for daily heating, ventilation and hot water supply of buildings significantly reduces the cost of creating the infrastructure of the territory under construction by eliminating the necessity of running the distribution network of heat or gas supply. The use of the heat accumulators is necessary due to the increase of the time-weighted average outdoor temperature. The mentioned increase in the City of Minsk in the heating season is of about 0.1 °C per year in average, and as for the last 20 years, the increase has led to a reduction of the required heat load on the premises by about 10 %. Research and project work on choosing the most effective options for the arrangement and use the heat accumulators in buildings of the various functions ought to be fulfilled in order to make the application of heat accumulators successful. In this respect civil and power engineers as well as operators should work together so to determine the chronological, technical and economic conditions of charging and use of heat accumulators.

  20. Passive annual heat storage principles in earth sheltered housing, a supplementary energy saving system in residential housing

    Energy Technology Data Exchange (ETDEWEB)

    Anselm, Akubue Jideofor [Green Architecture Department, School of Architecture and Urban Planning, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2008-07-01

    This paper looks through the many benefits of earth not only as a building element in its natural form but as a building mass, energy pack and spatial enclosure which characterized by location, unique physical terrain and climatic factors can be utilized in developing housing units that will provide the needed benefits of comfort alongside the seasons. Firstly the study identifies existing sunken earth houses in the North-west of China together with identifying the characters that formed the ideas behind the choice of going below the ground. Secondly, the study examines the pattern of heat exchange, heat gains and losses as to identify the principles that makes building in earth significant as an energy conservation system. The objective of this, is to relate the ideas of sunken earth home design with such principles as the passive annual heat storage systems (PAHS) in producing houses that will serve as units used to collect free solar heat all summer and cools passively while heating the earth around it and also keeping warm in winter by retrieving heat from the soil while utilizing the free solar heat stored throughout the summer as a year-round natural thermal resource. (author)

  1. Effect of storage time on microbial quality of some spices and dried seasonings

    International Nuclear Information System (INIS)

    Adu-Gyamfi, A.

    2006-01-01

    The effect of storage time on the microbial quality of some spices and dried seasonings (SOS) (dawadawa, pepper, ginger, shrimp and fish powders) was studied over a 12-month period. Microbial load and profile of irradiated and unirradiated SOS were assessed at 0, 6 and 12-month periods. The range of total variable counts (TVCs) were initially determined at 0.81-4.53 and 4.658.51 log 10 cfu g -1 for irradiated and un irradiated SDS, respectively; those for mould and yeast counts (MYCs) were determined at 0-1.74 and 1.55-3.35 log 10 cfu g -1 , respectively. Generally, TVCs were not significantly affected (P<0.05) by the 6 and 12-month periods, but MYCs were significantly reduced (P<0.05) after the storage periods in some SDS. Microbial profile, mainly dominated by Bacillus spp., Laclobacillus spp., Clostridium spp., Aspergillus spp. and Penicillium spp., was stable after the 6 and 12-month periods for all the SDS. However, the profile was consistently more diverse on dawadawa. pepper and ginger powders. No adverse change in microbial quality of irradiated and unirradiated SDS was observed at the end of the storage periods

  2. Sensitivity Analysis of Depletion Parameters for Heat Load Evaluation of PWR Spent Fuel Storage Pool

    International Nuclear Information System (INIS)

    Kim, In Young; Lee, Un Chul

    2011-01-01

    As necessity of safety re-evaluation for spent fuel storage facility has emphasized after the Fukushima accident, accuracy improvement of heat load evaluation has become more important to acquire reliable thermal-hydraulic evaluation results. As groundwork, parametric and sensitivity analyses of various storage conditions for Kori Unit 4 spent fuel storage pool and spent fuel depletion parameters such as axial burnup effect, operation history, and specific heat are conducted using ORIGEN2 code. According to heat load evaluation and parametric sensitivity analyses, decay heat of last discharged fuel comprises maximum 80.42% of total heat load of storage facility and there is a negative correlation between effect of depletion parameters and cooling period. It is determined that specific heat is most influential parameter and operation history is secondly influential parameter. And decay heat of just discharged fuel is varied from 0.34 to 1.66 times of average value and decay heat of 1 year cooled fuel is varied from 0.55 to 1.37 times of average value in accordance with change of specific power. Namely depletion parameters can cause large variation in decay heat calculation of short-term cooled fuel. Therefore application of real operation data instead of user selection value is needed to improve evaluation accuracy. It is expected that these results could be used to improve accuracy of heat load assessment and evaluate uncertainty of calculated heat load.

  3. Current status of and problems in ice heat storage systems contributing to improving load rate. Proliferation of the ice heat storage type air conditioning system and roles of the Heat Pump and Heat Storage Center; Fukaritsu kaizen ni kokensuru kori chikunetsu system no genjo to kadai. Kori chikunetsushiki kucho system no fukyu to heat pump chikunetsu center no yakuwari

    Energy Technology Data Exchange (ETDEWEB)

    Miyata, T.

    1998-02-01

    This paper introduces the roles played by the `Heat Pump and Heat Storage Center`. This foundation had been performing research and development and international information exchange in devices and equipment as the `Heat Pump Technology Development Center`. Development of heat storage type air conditioning systems as a measure for load leveling, and efforts of their proliferation and enlightenment were added to the business activities. As a result, the foundation`s name was changed to the present name. Its activities being planned and performed include: interest supplementing operation for installation of an air conditioning system of the heat pump system using storage of latent heat such as ice heat storage, holding seminars for promoting proliferation of the ice heat storage type air conditioning system, opening the home page, participation in exhibitions of various types, and preparation of different publicity tools. More specifically, carrying series advertisements in newspapers and magazines, holding nation-wide symposiums tying up with Japan Economic Press, publishing an organ newspaper targeted at both of experts and general people, and preparation of general pamphlets to introduce comprehensively the information about heat storage. 3 figs., 1 tab.

  4. Ground source geothermal heat. Ground source heat pumps and underground thermal energy storage systems. Proceedings; Oberflaechennahe Geothermie. Erdgekoppelte Waermepumpen und unterirdische thermische Energiespeicher. Tagungsband

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2009-07-01

    At the ninth international user forum on shallow geothermal heat on 28th and 29th April, 2009, at BadStaffelstein (Federal Republic of Germany), the following lectures were held: (1) Information system on shallow geothermal heat for Bavaria (Marcellus Schulze); (2) Calculation of the spreading of temperature anomalies in groundwater as an instrument of planning of heat pump systems (Wolfgang Rauch); (3) Comparison of models for simulation of deep geothermal probes (Markus Proell); (4) Impact of the geometry of boreholes and probes on heat transport (Manfred Reuss); (5) Thermal respond tests and temperature depth profiles - Experience from research and practice (Markus Kuebert); (6) A model of simulation for the investigation of the impact of different heat transfer fluids on the efficiency of ground source heat pump devices (Roland Koenigsdorff); (7) The research project EWSplus - Investigations for quality assurance of geothermal probes (Mathieu Riegger); (8) Quality management of plants for the utilization of shallow geothermal heat with geothermal probes - the example of Baden-Wuerttemberg (Bruno Lorinser, Ingrid Stober); (9) Not every heat pump contributes to climate protection (Falk Auer); (10) Field measurements of heat pumps in residential buildings with modern standard and in older buildings (Marek Miara); (11) System technology for a great annual performance factor (Werner Schenk); (12) Modification of older geothermal heat probe devices for use with modern heat pumps (Klaus Friedrich Staerk); (13) Energy-efficient modernisation of a pensioners' condominium from the 1970s with solar-geothermal-air (Michael Guigas); (14) Evaluation and optimization of operation of seasonal storage systems in the foundations of office buildings (Herdis Kipry); (15) Evaluation of an innovative heating and cooling concept with rain water vessels, thermo-active building components and phase change materials in a residential building (Doreen Kalz); (16) Contracts for ground

  5. Behavioural responses to thermal conditions affect seasonal mass change in a heat-sensitive northern ungulate.

    Directory of Open Access Journals (Sweden)

    Floris M van Beest

    Full Text Available BACKGROUND: Empirical tests that link temperature-mediated changes in behaviour (activity and resource selection to individual fitness or condition are currently lacking for endotherms yet may be critical to understanding the effect of climate change on population dynamics. Moose (Alces alces are thought to suffer from heat stress in all seasons so provide a good biological model to test whether exposure to non-optimal ambient temperatures influence seasonal changes in body mass. Seasonal mass change is an important fitness correlate of large herbivores and affects reproductive success of female moose. METHODOLOGY/PRINCIPAL FINDINGS: Using GPS-collared adult female moose from two populations in southern Norway we quantified individual differences in seasonal activity budget and resource selection patterns as a function of seasonal temperatures thought to induce heat stress in moose. Individual body mass was recorded in early and late winter, and autumn to calculate seasonal mass changes (n = 52 over winter, n = 47 over summer. We found large individual differences in temperature-dependent resource selection patterns as well as within and between season variability in thermoregulatory strategies. As expected, individuals using an optimal strategy, selecting young successional forest (foraging habitat at low ambient temperatures and mature coniferous forest (thermal shelter during thermally stressful conditions, lost less mass in winter and gained more mass in summer. CONCLUSIONS/SIGNIFICANCE: This study provides evidence that behavioural responses to temperature have important consequences for seasonal mass change in moose living in the south of their distribution in Norway, and may be a contributing factor to recently observed declines in moose demographic performance. Although the mechanisms that underlie the observed temperature mediated habitat-fitness relationship remain to be tested, physiological state and individual variation in

  6. Behavioural responses to thermal conditions affect seasonal mass change in a heat-sensitive northern ungulate.

    Science.gov (United States)

    van Beest, Floris M; Milner, Jos M

    2013-01-01

    Empirical tests that link temperature-mediated changes in behaviour (activity and resource selection) to individual fitness or condition are currently lacking for endotherms yet may be critical to understanding the effect of climate change on population dynamics. Moose (Alces alces) are thought to suffer from heat stress in all seasons so provide a good biological model to test whether exposure to non-optimal ambient temperatures influence seasonal changes in body mass. Seasonal mass change is an important fitness correlate of large herbivores and affects reproductive success of female moose. Using GPS-collared adult female moose from two populations in southern Norway we quantified individual differences in seasonal activity budget and resource selection patterns as a function of seasonal temperatures thought to induce heat stress in moose. Individual body mass was recorded in early and late winter, and autumn to calculate seasonal mass changes (n = 52 over winter, n = 47 over summer). We found large individual differences in temperature-dependent resource selection patterns as well as within and between season variability in thermoregulatory strategies. As expected, individuals using an optimal strategy, selecting young successional forest (foraging habitat) at low ambient temperatures and mature coniferous forest (thermal shelter) during thermally stressful conditions, lost less mass in winter and gained more mass in summer. This study provides evidence that behavioural responses to temperature have important consequences for seasonal mass change in moose living in the south of their distribution in Norway, and may be a contributing factor to recently observed declines in moose demographic performance. Although the mechanisms that underlie the observed temperature mediated habitat-fitness relationship remain to be tested, physiological state and individual variation in thermal tolerance are likely contributory factors. Climate-related effects on animal

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

    International Nuclear Information System (INIS)

    Badescu, Viorel

    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 non-linear coupled partial differential equations for the temperature of the storage medium and heat transfer fluid, respectively. Preliminary results show that smaller TES units provide a higher heat flux to the heat pump vaporiser. This makes the small TES unit discharge more rapidly during time periods with higher thermal loads. The larger TES units provide heat during longer time periods, even if the heat flux they supply is generally smaller. The maximum heat flux is extracted from the TES unit during the morning. Both the heat pump COP and exergy efficiency decrease when the TES unit length increases. Also, the monthly thermal energy stored by the TES unit and the monthly energy necessary to drive the heat pump compressor are increased by increasing the TES unit length

  8. Seasonal variability of cyclone heat potential in the Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Sadhuram, Y.; Rao, B.P.; Rao, D.P.; Shastri, P.N.M.; Subrahmanyam, M.V.

    when it moved over the region of high heat potential (>90 kJ/cm 2 ) in the western Gulf of Mexico (Goni et al., 1996; Shay et al., 2000). Monitoring of warm core eddies and regions of high heat potential have become important to predict... bordered by Burma, Thailand, Sumatra and Andaman–Nicobar ridge. Heat storage of the Andaman Sea had been reported by Ramesh Babu and Sastry (1981), using IIOE Data set (1960–1965). Unfortunately, this region had not been covered for several decades after...

  9. Numerical Heat Transfer Studies of a Latent Heat Storage System Containing Nano-Enhanced Phase Change Material

    Directory of Open Access Journals (Sweden)

    S F Hosseinizadeh

    2011-01-01

    Full Text Available The heat transfer enhancement in the latent heat thermal energy storage system through dispersion of nanoparticle is reported. The resulting nanoparticle-enhanced phase change materials (NEPCM exhibit enhanced thermal conductivity in comparison to the base material. The effects of nanoparticle volume fraction and some other parameters such as natural convection are studied in terms of solid fraction and the shape of the solid-liquid phase front. It has been found that higher nanoparticle volume fraction result in a larger solid fraction. The present results illustrate that the suspended nanoparticles substantially increase the heat transfer rate and also the nanofluid heat transfer rate increases with an increase in the nanoparticles volume fraction. The increase of the heat release rate of the NEPCM shows its great potential for diverse thermal energy storage application.

  10. The Characteristic of Molten Heat Salt Storage System Utilizing Solar Energy Combined with Valley Electric

    Directory of Open Access Journals (Sweden)

    LI .Jiu-ru

    2017-02-01

    Full Text Available With the environmental pollution and energy consumption clue to the large difference between peak and valley of power grid,the molten salt heat storage system(MSHSS utilizing solar Energy combined with valley electric is presented for good energy saving and low emissions. The costs of MSHSS utilizing solar Energy combined with valley electric are greatly reduced. The law of heat transfer in molten salt heat storage technology is studied with the method of grey correlation analysis. The results show the effect of elbow sizes on surface convective heat transfer coefficient with different flow velocities.

  11. On energy optimisation in multipurpose batch plants using heat storage

    CSIR Research Space (South Africa)

    Majozi, T

    2010-10-01

    Full Text Available time interval. Indirect heat integration makes use of a heat transfer fluid for storing energy and allows heat integration of processes regardless of the time interval. This is possible as long as the source process takes place before the sink process...

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

    Science.gov (United States)

    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.

  13. State of Maine residential heating oil survey: 1995--1996 season summary

    International Nuclear Information System (INIS)

    Elder, B.

    1996-05-01

    In Maine the cash price is surveyed, as opposed to lthe retail or charge price, as it has been identified as the price most often paid by Maine consumers. As one can see from the chart in this report, the 1995-1996 cash prices for No. 2 heating oil can be characterized as having an upward trend and much more fluctuation than last years' relatively flat line. The 1995-96 heating season started at the closing price of the previous season and for the first few weeks prices were lower than most of the 1994-95 trendline. When the weather became cooler, however, prices were on a steady incline until well into the winter. Prices leveled off for most of the rest of the season with a dramatic surge on the last week of the survey. The average statewide cash price for No. 2 heating oil this year was .861 1 cents, approximately ten cents higher than the average for 1994-1995 which was .7661 cents per gallon. It has been the observation of the SPO that during most of the 1995-1996 season, Maine's prices showed a direct correspondence with New England rack or wholesale prices. It appeared that they never fluctuated more than 3-4 cents from each other

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  16. Heating and cooling system for an on-board gas adsorbent storage vessel

    Science.gov (United States)

    Tamburello, David A.; Anton, Donald L.; Hardy, Bruce J.; Corgnale, Claudio

    2017-06-20

    In one aspect, a system for controlling the temperature within a gas adsorbent storage vessel of a vehicle may include an air conditioning system forming a continuous flow loop of heat exchange fluid that is cycled between a heated flow and a cooled flow. The system may also include at least one fluid by-pass line extending at least partially within the gas adsorbent storage vessel. The fluid by-pass line(s) may be configured to receive a by-pass flow including at least a portion of the heated flow or the cooled flow of the heat exchange fluid at one or more input locations and expel the by-pass flow back into the continuous flow loop at one or more output locations, wherein the by-pass flow is directed through the gas adsorbent storage vessel via the by-pass line(s) so as to adjust an internal temperature within the gas adsorbent storage vessel.

  17. Application of thermal energy storage to process heat recovery in the aluminum industry

    Science.gov (United States)

    Mccabe, J.

    1980-01-01

    The economic viability and the institutional compatibility of a district heating system in the city of Bellingham, Washington are assessed and the technical and economic advantages of using thermal energy storage methods are determined.

  18. Heat storage in forest biomass significantly improves energy balance closure particularly during stable conditions

    Science.gov (United States)

    Lindroth, A.; Mölder, M.; Lagergren, F.

    2009-08-01

    Temperature measurements in trunks and branches in a mature ca. 100 years-old mixed pine and spruce forest in central Sweden were used to estimate the heat storage in the tree biomass. The estimated heat flux in the sample trees and data on biomass distributions were used to scale up to stand level biomass heat fluxes. The rate of change of sensible and latent heat storage in the air layer below the level of the flux measurements was estimated from air temperature and humidity profile measurements and soil heat flux was estimated from heat flux plates and soil temperature measurements. The fluxes of sensible and latent heat from the forest were measured with an eddy covariance system in a tower. The analysis was made for a two-month period in summer of 1995. The tree biomass heat flux was the largest of the estimated storage components and varied between 40 and -35 W m-2 on summer days with nice weather. Averaged over two months the diurnal maximum of total heat storage was 45 W m-2 and the minimum was -35 W m-2. The soil heat flux and the sensible heat storage in air were out of phase with the biomass flux and they reached maximum values that were about 75% of the maximum of the tree biomass heat storage. The energy balance closure improved significantly when the total heat storage was added to the turbulent fluxes. The slope of a regression line with sum of fluxes and storage as independent and net radiation as dependent variable, increased from 0.86 to 0.95 for half-hourly data and the scatter was also reduced. The most significant finding was, however, that during nights with strongly stable conditions when the sensible heat flux dropped to nearly zero, the total storage matched the net radiation nearly perfectly. Another interesting result was that the mean energy imbalance started to increase when the Richardson number became more negative than ca. -0.1. In fact, the largest energy deficit occurred at maximum instability. Our conclusion is that eddy

  19. On the development of an innovative gas-fired heating appliance based on a zeolite-water adsorption heat pump; system description and seasonal gas utilization efficiency

    International Nuclear Information System (INIS)

    Dawoud, Belal

    2014-01-01

    The main objective of this work is to introduce an innovative hybrid heating appliance incorporating a gas condensing boiler and a zeolite-water adsorption heat pump. The condensing boiler is applied to drive the zeolite-water heat pump for the heating base-load and to assist the heat pump in the so called “mixed operation” mode, in which both the heat pump and the condensing boiler are working in series to cover medium heating demands. Peak heating demands are covered by the condensing boiler in the so called “direct heating” mode. The three operation modes of the hybrid heating appliance have been technically described. In addition, the laboratory test conditions for estimating the seasonal heating performance according to the German Guideline VDI 4650-2 have been introduced. For both heating systems 35/28 °C and 55/45 °C, which represent the typical operating conditions of floor and high temperature radiating heating systems in Europe, seasonal heating gas utilization efficiencies of 1.34 and 1.26 have been measured, respectively with a ground heat source. In two field test installations in one-family houses in Germany, the introduced heating appliance showed 27% more seasonal gas utilization efficiency for heating and domestic hot water production, which is equivalent to a CO 2 -emission reduction of 20% compared to the gas condensing boiler technology

  20. Uses of the waste heat from the interim fuel storage facility

    International Nuclear Information System (INIS)

    Wehrum, A.

    It was the objective of this study to investigate the possibilities of a convenient use of the waste heat from the designed interim fuel storage at Ahaus. In this sense the following possibilities have been investigated: district heating, heat for industrial processes, fish-production, green house-heating, production of methane from original waste, agrotherm (agricultur field heating). It has been shown, that an economical behaviour for nearly all variations is not given without the financial help of the government, because of the high costs for heat transport and out-put. The most economical project is the intensive fish production plant. (orig.) [de

  1. 'Eco-house 99' - Full-scale demonstration of solar walls with building integrated heat storages

    Energy Technology Data Exchange (ETDEWEB)

    Hummelshoej, R.M.; Rahbek, J.E. [COWI Consulting Engineers and Planners AS (Denmark)

    2000-07-01

    A critical issue for solar systems in northern latitudes is the economic profitability. It is often said that the techniques for solar utilisation are expensive and unprofitable. This is, however, not always the case. A new project with 59 low energy terrace houses was carried out in Kolding, Denmark. The houses are designed as ecological buildings with emphasis on total economy based on low operation and maintenance costs, energy conservation and passive/hybrid solar utilisation. Besides direct solar gain through windows, each house has a solar wall of 6-8.5 m{sup 2} on the south facade. The solar walls are used both for heating of ventilation air and for space heating. The solar walls deliver heat to the dwellings during the heating season. To optimise the energy utilisation from the solar walls, the energy is stored internally in building integrated heat storages. Two different new types of prefabricated heat storages are built into the houses. One is an internal concrete wall with embedded ventilation pipes, and the other is a hollow concrete element with integrated stone bed. The heat storages are mainly designed to store solar energy from the day to the evening and the night. Because the solar walls and the heat storages have been a part of the design process from the start, the additional expenses are as low as 30-140 Euro/m{sup 2} solar wall compared with the alternative facade. This is far less than what it costs to add a solar wall on an existing building. Measurements over one year show that the yield of the solar walls is in the range of 115-125 kWh/m{sup 2}/year as expected. With the actual financing, the annual payment of the additional expenses for the solar systems is between 1-6 Euro/m{sup 2} solar wall, while the annual savings are about 5 Euro/year/m{sup 2} (with an energy price of 0.042 Euro/kWh). Dependent on which alternative facade construction the solar wall system is compared with, the profit of the system is in the range of 1 to +4 Euro

  2. Observed changes in seasonal heat waves and warm temperature extremes in the Romanian Carpathians

    Science.gov (United States)

    Micu, Dana; Birsan, Marius-Victor; Dumitrescu, Alexandru; Cheval, Sorin

    2015-04-01

    Extreme high temperature have a large impact on environment and human activities, especially in high elevation areas particularly sensitive to the recent climate warming. The climate of the Romanian Carpathians became warmer particularly in winter, spring and summer, exibiting a significant increasing frequency of warm extremes. The paper investigates the seasonal changes in the frequency, duration and intensity of heat waves in relation to the shifts in the daily distribution of maximum temperatures over a 50-year period of meteorological observations (1961-2010). The paper uses the heat wave definition recommended by the Expert Team on Climate Change Detection and Indices (ETCCDI) and exploits the gridded daily dataset of maximum temperature at 0.1° resolution (~10 km) developed in the framework of the CarpatClim project (www.carpatclim.eu). The seasonal changes in heat waves behavior were identified using the Mann-Kendall non-parametric trend test. The results suggest an increase in heat wave frequency and a lengthening of intervals affected by warm temperature extremes all over the study region, which are explained by the shifts in the upper (extreme) tail of the daily maximum temperature distribution in most seasons. The trends are consistent across the region and are well correlated to the positive phases of the East Atlantic Oscillation. Our results are in good agreement with the previous temperature-related studies concerning the Carpathian region. This study was realized within the framework of the project GENCLIM, financed by UEFISCDI, code PN-II 151/2014.

  3. Energy system investment model incorporating heat pumps with thermal storage in buildings and buffer tanks

    DEFF Research Database (Denmark)

    Hedegaard, Karsten; Balyk, Olexandr

    2013-01-01

    Individual compression heat pumps constitute a potentially valuable resource in supporting wind power integration due to their economic competitiveness and possibilities for flexible operation. When analysing the system benefits of flexible heat pump operation, effects on investments should...... be taken into account. In this study, we present a model that facilitates analysing individual heat pumps and complementing heat storages in integration with the energy system, while optimising both investments and operation. The model incorporates thermal building dynamics and covers various heat storage...... of operating heat pumps flexibly. This includes prioritising heat pump operation for hours with low marginal electricity production costs, and peak load shaving resulting in a reduced need for peak and reserve capacity investments....

  4. Steam-based Charging-Discharging of a PCM Heat Storage

    African Journals Online (AJOL)

    fire7-

    2016-11-10

    Nov 10, 2016 ... 2Department of Energy and Process Engineering, Norwegian University of Science and. Technology ... Keywords: Solar energy, PCM storage, Latent heat storage, Two-phase thermosyphon. 1. ..... principle, with water as the working fluid at about 35-bar pressure. ... generator as applied to PTC systems.

  5. Influence of heat treatment and veneering on the storage modulus and surface of zirconia ceramic

    NARCIS (Netherlands)

    Siavikis, G.; Behr, M.; van der Zel, J.M.; Feilzer, A.J.; Rosentritt, M.

    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

  6. Heat transfer modelling in a spent-fuel dry storage system

    International Nuclear Information System (INIS)

    Ritz, J.B.; Le Bonhomme, S.

    2001-01-01

    The purpose of this paper is to present a numerical modelling of heat transfers in a Spent-Fuel horizontal dry storage. The horizontal dry storage is an interesting issue to momentary store spent fuel containers before the final storage. From a thermal point of view, the cooling of spent fuel container by natural convection is a suitable and inexpensive process but it necessitates to well define the dimensions of the concept due to the difficulty to control the thermal environment. (author)

  7. Experimental study on heat storage system using phase-change material in a diesel engine

    International Nuclear Information System (INIS)

    Park, Sangki; Woo, Seungchul; Shon, Jungwook; Lee, Kihyung

    2017-01-01

    Engines usually use only about 25% of the total fuel energy for power, and the rest is discarded to the cooling water and exhaust gas. Therefore, a technique for utilizing external waste heat is required to improve fuel efficiency in terms of total energy consumption. In this study, a heat storage system was built using a phase-change material in order to recover about 30% of the thermal energy wasted through engine cooling. The components of the heat storage system were divided into phase-change material, a heat exchanger, and a heat-insulating container. For each component, a phase-change material that is suitable for use in vehicles was selected based on the safety, thermal properties, and durability. As a result, a stearic acid of a fatty acid series with natural extracts was determined to be appropriate. In order to measure the reduction in engine fuel consumption, a thermal storage system designed for the actual engine was applied to realize a quick warm-up by releasing stored heat energy directly on the coolant during a cold start. This technique added about 95 calories of heat storage device warm-up time compared to the non-added state, which was reduced by about 18.1% to about 27.1%. - Highlights: • The diesel engine used phase-change material with heat storage system. • The thermal storage system designed for the actual engine. • A stearic acid of a fatty acid series was determined to be appropriate. • Applied heat storage system was reduced by about 18.1%–27.1%.

  8. Parametric Study on the Dynamic Heat Storage Capacity of Building Elements

    DEFF Research Database (Denmark)

    Artmann, Nikolai; Manz, H.; Heiselberg, Per

    2007-01-01

    as their interrelation. The potential of increasing thermal mass by using phase change materials (PCM) was estimated assuming increased thermal capacity. The results show a significant impact of the heat transfer coefficient on heat storage capacity, especially for thick, thermally heavy elements. The storage capacity...... of onedimensional heat conduction in a slab with convective boundary condition was applied to quantify the dynamic heat storage capacity of a particular building element. The impact of different parameters, such as slab thickness, material properties and the heat transfer coefficient was investigated, as well......In modern, extensively glazed office buildings, due to high solar and internal loads and increased comfort expectations, air conditioning systems are often used even in moderate and cold climates. Particularly in this case, passive cooling by night-time ventilation seems to offer considerable...

  9. Aquifer thermal-energy-storage costs with a seasonal-chill source

    Science.gov (United States)

    Brown, D. R.

    1983-01-01

    The cost of energy supplied by an aquifer thermal energy storage (ATES) ystem from a seasonal chill source was investigated. Costs were estimated for point demand and residential development ATES systems using the computer code AQUASTOR. AQUASTOR was developed at PNL specifically for the economic analysis of ATES systems. In this analysis the cost effect of varying a wide range of technical and economic parameters was examined. Those parameters exhibiting a substantial influence on the costs of ATES delivered chill were: system size; well flow rate; transmission distance; source temperature; well depth; and cost of capital. The effects of each parameter are discussed. Two primary constraints of ATES chill systems are the extremely low energy density of the storage fluid and the prohibitive costs of lengthly pipelines for delivering chill to residential users. This economic analysis concludes that ATES-delivered chill will not be competitive for residential cooling applications. The otherwise marginal attractiveness of ATES chill systems vanishes under the extremely low load factors characteristic of residential cooling systems. (LCL)

  10. Experimental Study and Modeling of Ground-Source Heat Pumps with Combi-Storage in Buildings

    Directory of Open Access Journals (Sweden)

    Wessam El-Baz

    2018-05-01

    Full Text Available There is a continuous growth of heat pump installations in residential buildings in Germany. The heat pumps are not only used for space heating and domestic hot water consumption but also to offer flexibility to the grid. The high coefficient of performance and the low cost of heat storages made the heat pumps one of the optimal candidates for the power to heat applications. Thus, several questions are raised about the optimal integration and control of heat pump system with buffer storages to maximize its operation efficiency and minimize the operation costs. In this paper, an experimental investigation is performed to study the performance of a ground source heat pump (GSHP with a combi-storage under several configurations and control factors. The experiments were performed on an innovative modular testbed that is capable of emulating a ground source to provide the heat pump with different temperature levels at different times of the day. Moreover, it can emulate the different building loads such as the space heating load and the domestic hot water consumption in real-time. The data gathered from the testbed and different experimental studies were used to develop a simulation model based on Modelica that can accurately simulate the dynamics of a GSHP in a building. The model was validated based on different metrics. Energetically, the difference between the developed model and the measured values was only 3% and 4% for the heat generation and electricity consumption, respectively.

  11. Energy conservation indicators cold and heat storage. Revision factsheet cold and heat storage 2009; Besparingskentallen koude- en warmteopslag. Herziening factsheet koude- en warmteopslag 2009

    Energy Technology Data Exchange (ETDEWEB)

    Bosselaar, L. [SenterNovem, Utrecht (Netherlands); Koenders, M.J.B.; Van Helden, M.J.C.; Kleinlugtenbelt, J.H. [IF Technology, Arnhem (Netherlands)

    2009-08-15

    The aim of the title revision is to update the existing indicators for cold and heat storage as given in the Protocol Monitoring Sustainable Energy [Dutch] Het doel van het onderzoek is om de bestaande set van kentallen voor koude- en warmteopslag uit het Protocol Monitoring Duurzame Energie te actualiseren.

  12. Design optimization and sensitivity analysis of a biomass-fired combined cooling, heating and power system with thermal energy storage systems

    International Nuclear Information System (INIS)

    Caliano, Martina; Bianco, Nicola; Graditi, Giorgio; Mongibello, Luigi

    2017-01-01

    Highlights: • A novel operation strategy for biomass-fired combined cooling, heating and power system is presented. • A design optimization of the system is conducted. • The effects of variation of the incentive for the electricity generation are evaluated. • The effects of the variation of the absorption chiller size and the thermal energy storage system one are evaluated. • The inclusion of a cold storage system into the combined cooling, heating and power system is also analyzed. - Abstract: In this work, an operation strategy for a biomass-fired combined cooling, heating and power system, composed of a cogeneration unit, an absorption chiller, and a thermal energy storage system, is formulated in order to satisfy time-varying energy demands of an Italian cluster of residential multi-apartment buildings. This operation strategy is adopted for performing the economical optimization of the design of two of the devices composing the combined cooling, heating and power system, namely the absorption chiller and the storage system. A sensitivity analysis is carried out in order to evaluate the impact of the incentive for the electricity generation on the optimized results, and also to evaluate, separately, the effects of the variation of the absorption chiller size, and the effects of the variation of the thermal energy storage system size on the system performance. In addition, the inclusion into the system of a cold thermal energy storage system is analyzed, as well, assuming different possible values for the cold storage system cost. The results of the sensitivity analysis indicate that the most influencing factors from the economical point of view are represented by the incentive for the electricity generation and the absorption chiller power. Results also show that the combined use of a thermal energy storage and of a cold thermal energy storage during the hot season could represent a viable solution from the economical point of view.

  13. The relation of collector and storage tank size in solar heating systems

    International Nuclear Information System (INIS)

    Çomaklı, Kemal; Çakır, Uğur; Kaya, Mehmet; Bakirci, Kadir

    2012-01-01

    Highlights: ► A storage tank is used in many solar water heating systems for the storage of hot water. ► Using larger storage tanks decrease the efficiency and increases the cost of the system. ► The optimum tank size for the collector area is very important for economic solar heating systems. ► The optimum sizes of the collectors and the storage tank are determined. - Abstract: The most popular method to benefit from the solar energy is to use solar water heating systems since it is one of the cheapest way to benefit from the solar energy. The investment cost of a solar water heating system is very low, and the maintenance costs are nearly zero. Using the solar energy for solar water heating (SWH) technology has been greatly improved during the past century. A storage tank is used in many solar water heating systems for the conservation of heat energy or hot water for use when some need it. In addition, domestic hot water consumption is strongly variable in many buildings. It depends on the geographical situation, also on the country customs, and of course on the type of building usage. Above all, it depends on the inhabitants’ specific lifestyle. For that reason, to provide the hot water for consumption at the desirable temperature whenever inhabitants require it, there must be a good relevance between the collectors and storage tank. In this paper, the optimum sizes of the collectors and the storage tank are determined to design more economic and efficient solar water heating systems. A program has been developed and validated with the experimental study and environmental data. The environmental data were obtained through a whole year of operation for Erzurum, Turkey.

  14. Heat removal tests on dry storage facilities for nuclear spent fuels

    International Nuclear Information System (INIS)

    Wataru, M.; Saegusa, T.; Koga, T.; Sakamoto, K.; Hattori, Y.

    1999-01-01

    In Japan, spent fuel generated in NPP is controlled and stored in dry storage facility away-from reactor. Natural convection cooling system of the storage facility is considered advantageous from both safety and economic point of view. In order to realize this type of facility it is necessary to develop an evaluation method for natural convection characteristics and to make a rational design taking account safety and economic factors. Heat removal tests with the reduces scale models of storage facilities (cask, vault and silo) identified the the flow pattern in the test modules. The temperature and velocity distributions were obtained and the heat transfer characteristics were evaluated

  15. The underground heat storage for solar-assisted district heating in Neckarsulm. First measuring results; Der Erdsonden-Waermespeicher fuer die solarunterstuetzte Nahwaermeversorgung in Neckarsulm. Erste Messergebnisse

    Energy Technology Data Exchange (ETDEWEB)

    Seiwald, H.; Hahne, E. [Stuttgart Univ. (Germany). Inst. fuer Thermodynamik und Waermetechnik

    1998-12-31

    A solar-assisted district heating system with seasonal underground heat storage is currently under construction in Neckarsulm (Baden-Wurttemberg). In the new residential area approximately 1,300 flats are going to be built during the next years. The overall energy demand (hot water and space heating) is supposed to be covered by 50% with solar energy. During the first phase the project will be subsidised in the frame of the BMBF programme `Solarthermie 2000, Teilprogramm III`. A solar plant consisting of 2,700 square metres of collectors, a buffer tank (100 cubic metre) and an underground heat storage with a volume of approx. 20,000 cubic metres will be constructed by the end of 1998. It will be the first plant in Germany where thermal energy generated of solar energy is stored at high temperatures (up to 80 C) directly in the earth and utilised without a heat pump. (orig.) [Deutsch] In Neckarsulm (Baden-Wuerttemberg) befindet sich derzeit eine solar unterstuetzte Nahwaermeversorgung mit saisonalem Endsonden-Waermespeicher im Aufbau. Im Neubaugebiet Amorbach werden in den naechsten Jahren rund 1300 Wohneinheiten entstehen, deren Gesamtwaermebedarf (Warmwasser und Raumheizung) zu rund 50% mit Sonnenenergie gedeckt werden soll. In der ersten Phase wird das Projekt im Rahmen des BMBF-Programms `Solarthermie 2000, Teilprogramm III` gefoerdert. Bis Ende 1998 wird eine Solaranlage bestehend aus 2.700 m{sup 2} Kollektoren, einem Pufferspeicher (100 m{sup 3}) und einem Endsonden-Waermespeicher mit einem Volumen von ca. 20.000 m{sup 3} erstellt. Damit wird in Deutschland erstmalig eine Anlage realisiert, bei der solar erzeugte Waerme auf hohem Temperaturniveau (bis zu 80 C) direkt im Erdreich gespeichert und ohne Waermepumpe genutzt werden soll. (orig.)

  16. Quantifying Preferential Flow and Seasonal Storage in an Unsaturated Fracture-Facial Domain

    Science.gov (United States)

    Nimmo, J. R.; Malek-Mohammadi, S.

    2012-12-01

    Preferential flow through deep unsaturated zones of fractured rock is hydrologically important to a variety of contaminant transport and water-resource issues. The unsaturated zone of the English Chalk Aquifer provides an important opportunity for a case study of unsaturated preferential flow in isolation from other flow modes. The chalk matrix has low hydraulic conductivity and stays saturated, owing to its fine uniform pores and the wet climate of the region. Therefore the substantial fluxes observed in the unsaturated chalk must be within fractures and interact minimally with matrix material. Price et al. [2000] showed that irregularities on fracture surfaces provide a significant storage capacity in the chalk unsaturated zone, likely accounting for volumes of water required to explain unexpected dry-season water-table stability during substantial continuing streamflow observed by Lewis et al. [1993] In this presentation we discuss and quantify the dynamics of replenishment and drainage of this unsaturated zone fracture-face storage domain using a modification of the source-responsive model of Nimmo [2010]. This model explains the processes in terms of two interacting flow regimes: a film or rivulet preferential flow regime on rough fracture faces, active on an individual-storm timescale, and a regime of adsorptive and surface-tension influences, resembling traditional diffuse formulations of unsaturated flow, effective mainly on a seasonal timescale. The modified model identifies hydraulic parameters for an unsaturated fracture-facial domain lining the fractures. Besides helping to quantify the unsaturated zone storage described by Price et al., these results highlight the importance of research on the topic of unsaturated-flow relations within a near-fracture-surface domain. This model can also facilitate understanding of mechanisms for reinitiation of preferential flow after temporary cessation, which is important in multi-year preferential flow through deep

  17. Experimental process investigation of a latent heat energy storage system with a staggered heat exchanger with different phase change materials for solar thermal energy storage applications

    Science.gov (United States)

    Tsolakoglou, Nikolas P.; Koukou, Maria K.; Vrachopoulos, Michalis Gr.; Tachos, Nikolaos; Lymberis, Kostas; Stathopoulos, Vassilis

    2017-11-01

    This work investigates melting and solidification processes of four different Phase Change Materials (PCM) used as latent heat thermal storage system. The experimental rig was consisted of an insulated tank, filled with the under investigation PCM, a staggered heat exchanger to supply or extract heat from the PCM cavity and a water pump to circulate Heat Transfer Fluid (HTF). Both charging (melting) and discharging (solidification) processes were conducted for two different HTF flow rates. The main scope of this work was to develop a first approach and to investigate the behaviour of PCM under various load conditions (different HTF flow rates). Results show that different HTF flow rates affect melting and solidification time periods; in both processes time was reduced while HTF flow rate was increased but in differentways due to the transition from conduction to convection heat transfer mechanisms.

  18. Experimental process investigation of a latent heat energy storage system with a staggered heat exchanger with different phase change materials for solar thermal energy storage applications

    Directory of Open Access Journals (Sweden)

    Tsolakoglou Nikolas P.

    2017-01-01

    Full Text Available This work investigates melting and solidification processes of four different Phase Change Materials (PCM used as latent heat thermal storage system. The experimental rig was consisted of an insulated tank, filled with the under investigation PCM, a staggered heat exchanger to supply or extract heat from the PCM cavity and a water pump to circulate Heat Transfer Fluid (HTF. Both charging (melting and discharging (solidification processes were conducted for two different HTF flow rates. The main scope of this work was to develop a first approach and to investigate the behaviour of PCM under various load conditions (different HTF flow rates. Results show that different HTF flow rates affect melting and solidification time periods; in both processes time was reduced while HTF flow rate was increased but in differentways due to the transition from conduction to convection heat transfer mechanisms.

  19. Monitoring groundwater storage changes in the highly seasonal humid tropics: Validation of GRACE measurements in the Bengal Basin

    Science.gov (United States)

    Shamsudduha, M.; Taylor, R. G.; Longuevergne, L.

    2012-02-01

    Satellite monitoring of changes in terrestrial water storage provides invaluable information regarding the basin-scale dynamics of hydrological systems where ground-based records are limited. In the Bengal Basin of Bangladesh, we test the ability of satellite measurements under the Gravity Recovery and Climate Experiment (GRACE) to trace both the seasonality and trend in groundwater storage associated with intensive groundwater abstraction for dry-season irrigation and wet-season (monsoonal) recharge. We show that GRACE (CSR, GRGS) datasets of recent (2003 to 2007) groundwater storage changes (ΔGWS) correlate well (r = 0.77 to 0.93, p value CSR. Changes in surface water storage estimated from a network of 298 river gauging stations and soil-moisture derived from Land Surface Models explain 22% and 33% of ΔTWS, respectively. Groundwater depletion estimated from borehole hydrographs (-0.52 ± 0.30 km3 yr-1) is within the range of satellite-derived estimates (-0.44 to -2.04 km3 yr-1) that result from uncertainty associated with the simulation of soil moisture (CLM, NOAH, VIC) and GRACE signal-processing techniques. Recent (2003 to 2007) estimates of groundwater depletion are substantially greater than long-term (1985 to 2007) mean (-0.21 ± 0.03 km3 yr-1) and are explained primarily by substantial increases in groundwater abstraction for the dry-season irrigation and public water supplies over the last two decades.

  20. Theoretical Analysis for Heat Transfer Optimization in Subcritical Electrothermal Energy Storage Systems

    Directory of Open Access Journals (Sweden)

    Peng Hu

    2017-02-01

    Full Text Available Electrothermal energy storage (ETES provides bulk electricity storage based on heat pump and heat engine technologies. A subcritical ETES is described in this paper. Based on the extremum principle of entransy dissipation, a geometry model is developed for heat transfer optimization for subcritical ETES. The exergy during the heat transfer process is deduced in terms of entropy production. The geometry model is validated by the extremum principle of entropy production. The theoretical analysis results show that the extremum principle of entransy dissipation is an effective criterion for the optimization, and the optimum heat transfer for different cases with the same mass flux or pressure has been discussed. The optimum heat transfer can be achieved by adjusting the mass flux and pressure of the working fluid. It also reveals that with the increase of mass flux, there is a minimum exergy in the range under consideration, and the exergy decreases with the increase of the pressure.

  1. An integrated heat pipe-thermal storage design for a solar receiver

    Science.gov (United States)

    Keddy, E.; Sena, J. T.; Woloshun, K.; Merrigan, M. A.; Heidenreich, G.

    Light-weight heat pipe wall elements that incorporate a thermal storage subassembly within the vapor space are being developed as part of the Organic Rankine Cycle Solar Dynamic Power System (ORC-SDPS) receiver for the Space Station application. The operating temperature of the heat pipe elements is in the 770 to 810 K range with a design power throughput of 4.8 kW per pipe. The total heat pipe length is 1.9 M. The Rankine cycle boiler heat transfer surfaces are positioned within the heat pipe vapor space, providing a relatively constant temperature input to the vaporizer. The heat pipe design employs axial arteries and distribution wicked thermal storage units with potassium as the working fluid. Performance predictions for this configuration have been conducted and the design characterized as a function of artery geometry, distribution wick thickness, porosity, pore size, and permeability.

  2. Laboratory test of a prototype heat storage module based on stable supercooling of sodium acetate trihydrate

    DEFF Research Database (Denmark)

    Dannemand, Mark; Kong, Weiqiang; Fan, Jianhua

    2015-01-01

    Laboratory test of a long term heat storage module utilizing the principle of stable supercooling of 199.5 kg of sodium acetate water mixture has been carried out. Avoiding phase separation of the incongruently melting salt hydrate by using the extra water principle increased the heat storage...... capacity. An external expansion vessel minimized the pressure built up in the module while heating and reduced the risk of instable supercooling. The module was stable supercooled at indoor ambient temperature for up to two months after which it was discharged. The energy discharged after activating...

  3. Daily heat storage for a concentrating solar cooker; Tages-Hitzespeicher fuer einen konzentrierenden Solarkocher

    Energy Technology Data Exchange (ETDEWEB)

    Goetz, M.

    2002-07-01

    This report for the Swiss Federal Office of Energy (SFOE) describes a project that concerned the development and testing of two storage heating elements for automatic parabolic solar cookers. The first variant is made of solid aluminium and stores sensible heat; the second one is filled with tin and uses the latent heat of the solid-liquid phase-change of the tin as well as the storage of sensible heat, too. Various materials for use in heat storage - metals and salts - were examined. Tin was finally chosen for further experiments. The author concludes that the storage units work well, whereby the tin variant was more flexible for changing-weather conditions because of its latent heat storage. Because of their weight, however, the mobile use of the units is restricted. Suggestions for further development are made, including the integration of the units in the bases of solar cookers and the simplification of their construction. The article also reviews the development and application of concentrating-mirror solar cooking systems in India, where large-scale use can be found.

  4. Experimental investigations on cylindrical latent heat storage units with sodium acetate trihydrate composites utilizing supercooling

    DEFF Research Database (Denmark)

    Dannemand, Mark; Johansen, Jakob Berg; Kong, Weiqiang

    2016-01-01

    Latent heat storage units utilizing stable supercooling of sodium acetate trihydrate (SAT) composites were tested in a laboratory. The stainless steel units were 1.5 m high cylinders with internal heat exchangers of tubes with fins. One unit was tested with 116 kg SAT with 6% extra water. Another...... in the thickened phase change material after melting. The heat content in the fully charged state and the heat released after solidification of the supercooled SAT mixtures at ambient temperature was higher for the unit with the thickened SAT mixture. The heat discharged after solidification of the supercooled SAT...

  5. Flexibility of Large-Scale Solar Heating Plant with Heat Pump and Thermal Energy Storage

    DEFF Research Database (Denmark)

    Luc, Katarzyna Marta; Heller, Alfred; Rode, Carsten

    2017-01-01

    to decrease biomass use in a district heating system. The paper focuses on the renewable energy-based district heating system in Marstal, Denmark, with heat produced in central solar heating plant, wood pellet boiler, heat pump and bio-oil boiler. The plant has been the object of research and developments...

  6. Seasonal and geographical variation in heat tolerance and evaporative cooling capacity in a passerine bird.

    Science.gov (United States)

    Noakes, Matthew J; Wolf, Blair O; McKechnie, Andrew E

    2016-03-01

    Intraspecific variation in avian thermoregulatory responses to heat stress has received little attention, despite increasing evidence that endothermic animals show considerable physiological variation among populations. We investigated seasonal (summer versus winter) variation in heat tolerance and evaporative cooling in an Afrotropical ploceid passerine, the white-browed sparrow-weaver (Plocepasser mahali; ∼ 47 g) at three sites along a climatic gradient with more than 10 °C variation in mid-summer maximum air temperature (Ta). We measured resting metabolic rate (RMR) and total evaporative water loss (TEWL) using open flow-through respirometry, and core body temperature (Tb) using passive integrated transponder tags. Sparrow-weavers were exposed to a ramped profile of progressively higher Ta between 30 and 52 °C to elicit maximum evaporative cooling capacity (N=10 per site per season); the maximum Ta birds tolerated before the onset of severe hyperthermia (Tb ≈ 44 °C) was considered to be their hyperthermia threshold Ta (Ta,HT). Our data reveal significant seasonal acclimatisation of heat tolerance, with a desert population of sparrow-weavers reaching significantly higher Ta in summer (49.5 ± 1.4 °C, i.e. higher Ta,HT) than in winter (46.8 ± 0.9 °C), reflecting enhanced evaporative cooling during summer. Moreover, desert sparrow-weavers had significantly higher heat tolerance and evaporative cooling capacity during summer compared with populations from more mesic sites (Ta,HT=47.3 ± 1.5 and 47.6 ± 1.3 °C). A better understanding of the contributions of local adaptation versus phenotypic plasticity to intraspecific variation in avian heat tolerance and evaporative cooling capacity is needed for modelling species' responses to changing climates. © 2016. Published by The Company of Biologists Ltd.

  7. Small scale changes of geochemistry and flow field due to transient heat storage in aquifers

    Science.gov (United States)

    Bauer, S.; Boockmeyer, A.; Li, D.; Beyer, C.

    2013-12-01

    Heat exchangers in the subsurface are increasingly installed for transient heat storage due to the need of heating or cooling of buildings as well as the interim storage of heat to compensate for the temporally fluctuating energy production by wind or solar energy. For heat storage to be efficient, high temperatures must be achieved in the subsurface. Significant temporal changes of the soil and groundwater temperatures however effect both the local flow field by temperature dependent fluid parameters as well as reactive mass transport through temperature dependent diffusion coefficients, geochemical reaction rates and mineral equilibria. As the use of heat storage will be concentrated in urban areas, the use of the subsurface for (drinking) water supply and heat storage will typically coincide and a reliable prognosis of the processes occurring is needed. In the present work, the effects of a temporal variation of the groundwater temperature, as induced by a local heat exchanger introduced into a groundwater aquifer, are studied. For this purpose, the coupled non-isothermal groundwater flow, heat transport and reactive mass transport is simulated in the near filed of such a heat exchanger. By explicitly discretizing and incorporating the borehole, the borehole cementation and the heat exchanger tubes, a realistic geometrical and process representation is obtained. The numerical simulation code OpenGeoSys is used in this work, which incorporates the required processes of coupled groundwater flow, heat and mass transport as well as temperature dependent geochemistry. Due to the use of a Finite Element Method, a close representation of the geometric effects can be achieved. Synthetic scenario simulations for typical settings of salt water formations in northern Germany are used to investigate the geochemical effects arising from a high temperature heat storage by quantifying changes in groundwater chemistry and overall reaction rates. This work presents the

  8. Inherently safe aircooling for the storage of self-heating configurations of radionuclides

    International Nuclear Information System (INIS)

    Hame, W.; Klein, D.; Pirk, H.

    1980-01-01

    NUKEM developed a technical concept of a radionuclide storage facility based on aircooling, which provides that - the radionuclides, i.e. spent fuel elements, are tightly canned in steel canisters - the canned elements are put into individual cooling channels, which form the storage rack within the storage cell - the produced heat is removed from the surface of the canisters through free convection. This cooling concept shows the following advantages: - The cooling is inherently safe, as the driving force of the coolant is reliably supplied by the heat production of the system to be cooled. - The system is self-controlled and self-regulated because of the physically based correlation of heat production, heat transfer coefficients and air flow resistances. (orig.) 891 RB/orig. 892 MKO [de

  9. Development of a thermal storage system based on the heat of adsorption of water in hygroscopic materials

    NARCIS (Netherlands)

    Wijsman, A.J.T.M.; Oosterhaven, R.; Ouden, C. den

    1979-01-01

    A thermal storage system based on the heat of adsorption of water in hygroscopic materials has been studied as a component of a solar space heating system. The aim of this project is to decrease the storage volume in comparison with a rock-bed storage system by increasing the stored energy density.

  10. Using Heat Pump Energy Storages in the Power Grid

    DEFF Research Database (Denmark)

    Pedersen, Tom S.; Andersen, Palle; Nielsen, Kirsten M.

    2011-01-01

    The extensive growth of installed wind energy plants lead to increasing balancing problems in the power grid due to the nature of wind fields and diurnal variations in consumption. One way to overcome these problems is to move consumption to times where wind power otherwise cause overproduction...... and large fluctuations in prices. The paper presents a method which takes advantage of heat capacity in single-family houses using heat pumps which are anticipated to be installed in large numbers in Denmark in next decade. This type of heating gives a large time constant and it is shown possible to move...

  11. In-season heat stress compromises postharvest quality and low-temperature sweetening resistance in potato (Solanum tuberosum L.).

    Science.gov (United States)

    Zommick, Daniel H; Knowles, Lisa O; Pavek, Mark J; Knowles, N Richard

    2014-06-01

    The effects of soil temperature during tuber development on physiological processes affecting retention of postharvest quality in low-temperature sweetening (LTS) resistant and susceptible potato cultivars were investigated. 'Premier Russet' (LTS resistant), AO02183-2 (LTS resistant) and 'Ranger Russet' (LTS susceptible) tubers were grown at 16 (ambient), 23 and 29 °C during bulking (111-164 DAP) and maturation (151-180 DAP). Bulking at 29 °C virtually eliminated yield despite vigorous vine growth. Tuber specific gravity decreased as soil temperature increased during bulking, but was not affected by temperature during maturation. Bulking at 23 °C and maturation at 29 °C induced higher reducing sugar levels in the proximal (basal) ends of tubers, resulting in non-uniform fry color at harvest, and abolished the LTS-resistant phenotype of 'Premier Russet' tubers. AO02183-2 tubers were more tolerant of heat for retention of LTS resistance. Higher bulking and maturation temperatures also accelerated LTS and loss of process quality of 'Ranger Russet' tubers, consistent with increased invertase and lower invertase inhibitor activities. During LTS, tuber respiration fell rapidly to a minimum as temperature decreased from 9 to 4 °C, followed by an increase to a maximum as tubers acclimated to 4 °C; respiration then declined over the remaining storage period. The magnitude of this cold-induced acclimation response correlated directly with the extent of buildup in sugars over the 24-day LTS period and thus reflected the effects of in-season heat stress on propensity of tubers to sweeten and lose process quality at 4 °C. While morphologically indistinguishable from control tubers, tubers grown at elevated temperature had different basal metabolic (respiration) rates at harvest and during cold acclimation, reduced dormancy during storage, greater increases in sucrose and reducing sugars and associated loss of process quality during LTS, and reduced ability to improve

  12. Natural drying treatments during seasonal storage of wood for bioenergy in different European locations

    International Nuclear Information System (INIS)

    Roeser, Dominik; Mola-Yudego, Blas; Sikanen, Lauri; Prinz, Robert; Gritten, David; Emer, Beatrice; Vaeaetaeinen, Kari; Erkkilae, Ari

    2011-01-01

    Research into the methods of producing high quality wood chips for a rapidly growing energy sector is becoming increasingly important. For example, small wood chip heating plants require high quality wood chips to ensure efficient operation, thereby minimizing maintenance costs. Moisture content is considered to be an important quality parameter regarding wood based fuels. The objective of this study is to investigate methods to promote the natural drying of wood for bioenergy purposes. The effects on the drying process through covering the wood piles and partial debarking of stems were tested in order to identify methods to reduce the moisture content of the woody material in the storage. Drying trials were established in Finland, Italy and Scotland, utilizing tree species typically used for energy purposes in each area. The results show that natural drying is a viable and effective method to enhance the energy efficiency of wood based fuel products in all the regions studied. Furthermore, by adapting current harvesting methods and storage procedures even better results can be achieved. In addition, the results also indicate that broadleaved trees dry more effectively, if some partial debarking is carried out and that covering of piles is of utmost importance in Scotland and Finland. -- Highlights: → Natural drying is an effective method to enhance efficiency in the wood-fuel chains → Broadleaved trees dry more effectively when partial debarking is done → In Scotland and Finland a method for covering of piles is of utmost importance.

  13. Analysis of an underground electric heating system with short-term energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Ramadan, B.H. [Michigan State Univ., East Lansing, MI (United States). Dept. of Mechanical Engineering

    1994-12-31

    The principal commercially active heat storage application in which concrete is used as the storage medium is in the use of subfloor electric heaters embedded in a layer of sand. The resistance heaters are energized when utility offpeak rates are in effect. The sand bed and the concrete floor are then heated to some predetermined temperature, and the floor releases heat slowly and remains warm during the subsequent period of high demand. Analysis of the slab-heating system for varying design parameters, such as the depth of the placement of the heaters, the sand properties, the energy input, and the insulation thickness, was considered. The system was also optimized based on life-cycle costs. The suitability of using this system for heating a warehouse in four representative cities in the United States was also considered The response of the system was found to be greatly influenced by the depth of the placement of the heaters, the sand`s moisture content, and the heating strategy. Optimum insulation levels were determined for the prototypical building in all four of the representative cities. Because of the difficulty of controlling the energy release from the heating mats, this system may not be suitable for heating residential and office buildings but may be more appropriate for heating maintenance and storage facilities.

  14. Heat removal characteristics of waste storage tanks. Revision 1

    International Nuclear Information System (INIS)

    Kummerer, M.

    1995-10-01

    A topical report that examines the relationship between tank heat load and maximum waste temperatures. The passive cooling response of the tanks is examined, and loss of active cooling in ventilated tanks is investigated

  15. Effects of origin, seasons and storage under different temperatures on germination of Senecio vulgaris (Asteraceae) seeds.

    Science.gov (United States)

    Ndihokubwayo, Noel; Nguyen, Viet-Thang; Cheng, Dandan

    2016-01-01

    Invasive plants colonize new environments, become pests and cause biodiversity loss, economic loss and health damage. Senecio vulgaris L. (Common groundsel, Asteraceae), a widely distributing cosmopolitan weed in the temperate area, is reported with large populations in the north-eastern and south-western part, but not in southern, central, or north-western parts of China. We studied the germination behavior of S. vulgaris to explain the distribution and the biological invasion of this species in China. We used seeds originating from six native and six invasive populations to conduct germination experiments in a climate chamber and under outdoor condition. When incubated in a climate chamber (15 °C), seeds from the majority of the populations showed >90% germination percentage (GP) and the GP was equal for seeds with a native and invasive origin. The mean germination time (MGT) was significantly different among the populations. Under outdoor conditions, significant effects of origin, storage conditions (stored at 4 °C or ambient room temperature, ca. 27 °C) and seasons (in summer or autumn) were observed on the GP while the MGT was only affected by the season. In autumn, the GP (38.6%) was higher and the MGT was slightly longer than that in summer. In autumn, seeds stored at 4 °C showed higher GP than those stored at ambient room temperature (ca.27 °C), and seeds from invasive populations revealed higher GP than those from native populations. The results implied that the high temperature in summer has a negative impact on the germination and might cause viability loss or secondary dormancy to S. vulgaris seeds. Our study offers a clue to exploring what factor limits the distribution of S. vulgaris in China by explaining why, in the cities in South-East China and central China such as Wuhan, S. vulgaris cannot establish natural and viable populations.

  16. Effects of origin, seasons and storage under different temperatures on germination of Senecio vulgaris (Asteraceae seeds

    Directory of Open Access Journals (Sweden)

    Noel Ndihokubwayo

    2016-08-01

    Full Text Available Invasive plants colonize new environments, become pests and cause biodiversity loss, economic loss and health damage. Senecio vulgaris L. (Common groundsel, Asteraceae, a widely distributing cosmopolitan weed in the temperate area, is reported with large populations in the north–eastern and south–western part, but not in southern, central, or north-western parts of China. We studied the germination behavior of S. vulgaris to explain the distribution and the biological invasion of this species in China. We used seeds originating from six native and six invasive populations to conduct germination experiments in a climate chamber and under outdoor condition. When incubated in a climate chamber (15 °C, seeds from the majority of the populations showed >90% germination percentage (GP and the GP was equal for seeds with a native and invasive origin. The mean germination time (MGT was significantly different among the populations. Under outdoor conditions, significant effects of origin, storage conditions (stored at 4 °C or ambient room temperature, ca. 27 °C and seasons (in summer or autumn were observed on the GP while the MGT was only affected by the season. In autumn, the GP (38.6% was higher and the MGT was slightly longer than that in summer. In autumn, seeds stored at 4 °C showed higher GP than those stored at ambient room temperature (ca.27 °C, and seeds from invasive populations revealed higher GP than those from native populations. The results implied that the high temperature in summer has a negative impact on the germination and might cause viability loss or secondary dormancy to S. vulgaris seeds. Our study offers a clue to exploring what factor limits the distribution of S. vulgaris in China by explaining why, in the cities in South-East China and central China such as Wuhan, S. vulgaris cannot establish natural and viable populations.

  17. Smart electric storage heating and potential for residential demand response

    OpenAIRE

    Darby, S

    2017-01-01

    Low-carbon transition plans for temperate and sub-polar regions typically involve some electrification of space heating. This poses challenges to electricity system operation and market design, as it increases overall demand and alters the temporal patterns of that demand. One response to the challenge is to ‘smarten’ electrical heating, enabling it to respond to network conditions by storing energy at times of plentiful supply, releasing it in response to customer demands and offering rapid-...

  18. Maximizing Storage Flexibility in an Aggregated Heat Pump Portfolio

    DEFF Research Database (Denmark)

    Pedersen, Tom S.; Nielsen, Kirsten M.; Andersen, Palle

    2014-01-01

    for storage capability. It is of great importance to move energy consumption in time to balance the grid. In this paper a portfolio of houses are modelled and controlled using an aggregated model and a model free scheduling algorithm. Flexibility and ability to trade on the intra-day regulating market...

  19. The role of seasonal sediment storage in tidal channels on a mesotidal delta

    Science.gov (United States)

    Hale, R. P.; Wilson, C.; Bomer, J.; Goodbred, S. L., Jr.; Bain, R. L.

    2017-12-01

    The Sundarbans National Forest (SNF), located on the modern topset of the Ganges-Brahmaputra-Meghna (GBM) Delta, is the world's largest mangrove stand ( 10,000 km2), and provides a wide range of cultural, environmental, and economic benefits to the nation of Bangladesh. At present, sediment accretion in the SNF occurs at a rate comparable to that of the locally accelerated sea-level rise ( 1.1 cm/yr), despite substantial modification of the regional hydrodynamics via the construction of channel embankments to prevent inundation of agricultural areas. Approximately 50% of the sediment deposited in the SNF each year is recently delivered (water diversions associated with India's National River Linking Project raises serious concerns over the SNF's continued sustainability. Here, we examine: 1) the capacity for short-term sediment storage within tidal channels of varying dimensions, and 2) the hydrodynamic conditions responsible for resuspending this material and delivering it to the mangrove platform. We compare textural and radiochemical characteristics from short cores (<50 cm) collected along the intertidal channel banks, with those from the mangrove platform, to assess seasonal storage of GBM sediment within tidal channels, and the timeframe of its delivery to the SNF platform. We also present instrument data from multiple locations within a confined basin of the SNF, using an upward-looking acoustic Doppler current profiler, pressure sensors, and optical backscatter sensors, to document how transport conditions vary with distance away from the primary tidal inlet, and across the platform. This collection of physical and instrumental observations is then compared to an existing dataset of platform inundation hydroperiods and deposition rates, allowing us to address the threat of a reduced sediment supply to this region, as well as the capacity for this system to self-supply sediment to the platform.

  20. Numerical simulation of a heat pump assisted regenerative solar still with PCM heat storage for cold climates of Kazakhstan

    Directory of Open Access Journals (Sweden)

    Shakir Yessen

    2017-01-01

    Full Text Available A numerical model has been proposed in this work for predicting the energy performances of the heat pump assisted regenerative solar still with phase changing material heat storage under Kazakhstan climates. The numerical model is based on energy and mass balance. A new regenerative heat pump configuration with phase changing material heat storage is proposed to improve the performance. A comparison of results has been made between the conventional solar still and heat pump assisted regenerative solar still with phase changing material. The numerical simulation was performed for wide range of ambient temperatures between -30 and 30°C with wide range of solar intensities between 100 and 900 W/m2. The numerical simulation results showed that heat pump assisted regenerative solar still is more energy efficient and produce better yield when compared to the conventional simple solar still. The influences of solar intensity, ambient temperature, different phase changing materials, heat pump operating temperatures are discussed. The predicted values were found to be in good agreement with experimental results reported in literature.

  1. Investigation of a 10 kWh sorption heat storage device for effective utilization of low-grade thermal energy

    International Nuclear Information System (INIS)

    Zhao, Y.J.; Wang, R.Z.; Li, T.X.; Nomura, Y.

    2016-01-01

    Heating and domestic hot water for family houses represents a notable share of energy consumption. However, sufficient space for the installation of thermal energy storage (TES) components may not be available in family houses or urban areas, where space may be restricted and expensive. Sorption TES devices seem to be a promising means of replacing conventional TES devices and reducing the occupied space for its high energy density. In this paper, a 10 kWh short-term sorption TES device was developed and investigated. The employed composite sorbent was formed from lithium chloride (LiCl) with the addition of expanded graphite (EG). The principle of sorption TES for the LiCl/water working pair is first illustrated. This prototype was tested under conditions representative of transition or winter seasons. Under the conditions used (charging temperature T_c_h_a at 85 °C, discharging temperature T_d_i_s at 40 °C, condensing temperature T_c at 18 °C, and evaporating temperature T_e at 30 °C), the heat storage capacity can reach 10.25 kWh, of which sorption heat accounts for approximately 60%. The heat storage density obtained was 873 Wh per kg of composite sorbent or 65.29 kWh/m"3, while the heat storage density of hot water tank was about 33.02 kWh/m"3. - Highlights: • A 10 kWh short-term sorption thermal energy device was developed. • The device was tested under conditions of transition and winter seasons. • The performance of the device was improved by recovering waste heat. • The sorption thermal energy device was compared with a 300-L hot water tank.

  2. Work Rate during Self-paced Exercise is not Mediated by the Rate of Heat Storage.

    Science.gov (United States)

    Friesen, Brian J; Périard, Julien D; Poirier, Martin P; Lauzon, Martin; Blondin, Denis P; Haman, Francois; Kenny, Glen P

    2018-01-01

    To date, there have been mixed findings on whether greater anticipatory reductions in self-paced exercise intensity in the heat are mediated by early differences in rate of body heat storage. The disparity may be due to an inability to accurately measure minute-to-minute changes in whole-body heat loss. Thus, we evaluated whether early differences in rate of heat storage can mediate exercise intensity during self-paced cycling at a fixed rate of perceived exertion (RPE of 16; hard-to-very-hard work effort) in COOL (15°C), NORMAL (25°C), and HOT (35°C) ambient conditions. On separate days, nine endurance-trained cyclists exercised in COOL, NORMAL, and HOT conditions at a fixed RPE until work rate (measured after first 5 min of exercise) decreased to 70% of starting values. Whole-body heat loss and metabolic heat production were measured by direct and indirect calorimetry, respectively. Total exercise time was shorter in HOT (57 ± 20 min) relative to both NORMAL (72 ± 23 min, P = 0.004) and COOL (70 ± 26 min, P = 0.045). Starting work rate was lower in HOT (153 ± 31 W) compared with NORMAL (166 ± 27 W, P = 0.024) and COOL (170 ± 33 W, P = 0.037). Rate of heat storage was similar between conditions during the first 4 min of exercise (all P > 0.05). Thereafter, rate of heat storage was lower in HOT relative to NORMAL and COOL until 30 min of exercise (last common time-point between conditions; all P exercise. No differences were measured at end exercise. We show that rate of heat storage does not mediate exercise intensity during self-paced exercise at a fixed RPE in cool to hot ambient conditions.

  3. Transient modelling of heat loading of phase change material for energy storage

    Directory of Open Access Journals (Sweden)

    Asyraf W.M.

    2017-01-01

    Full Text Available As the development of solar energy is getting advance from time to time, the concentration solar technology also get the similar attention from the researchers all around the globe. This technology concentrate a large amount of energy into main spot. To collect all the available energy harvest from the solar panel, a thermal energy storage is required to convert the heat energy to one of the purpose such as electrical energy. With the idea of energy storage application that can be narrow down to commercial application such as cooking stove. Using latent heat type energy storage seem to be appropriate with the usage of phase change material (PCM that can release and absorb heat energy at nearly constant temperature by changing its state. Sodium nitrate (NaNO3 and potassium nitrate (KNO3 was selected to use as PCM in this project. This paper focus on the heat loading process and the melting process of the PCM in the energy storage using a computer simulation. The model of the energy storage was created as solid three dimensional modelling using computer aided software and the geometry size of it depend on how much it can apply to boil 1 kg of water in cooking application. The materials used in the tank, heat exchanger and the heat transfer fluid are stainless steel, copper and XCELTHERM MK1, respectively. The analysis was performed using a commercial simulation software in a transient state. The simulation run on different value of velocity but kept controlled under laminar state only, then the relationship of velocity and heat distribution was studied and the melting process of the PCM also has been analyzed. On the effect of heat transfer fluid velocity, the higher the velocity resulted in higher the rate of heat transfer. The comparison between the melting percentages of the PCMs under test conditions show that NaNO3 melts quite faster than KNO3.

  4. Nuclear combined cycle gas turbines for variable electricity and heat using firebrick heat storage and low-carbon fuels

    International Nuclear Information System (INIS)

    Forsberg, Charles; Peterson, Per F.; McDaniel, Patrick; Bindra, Hitesh

    2017-01-01

    The world is transitioning to a low-carbon energy system. Variable electricity and industrial energy demands have been met with storable fossil fuels. The low-carbon energy sources (nuclear, wind and solar) are characterized by high-capital-costs and low-operating costs. High utilization is required to produce economic energy. Wind and solar are non-dispatchable; but, nuclear is the dispatchable energy source. Advanced combined cycle gas turbines with firebrick heat storage coupled to high-temperature reactors may enable economic variable electricity and heat production with constant full-power reactor output. Such systems efficiently couple to fluoride-salt-cooled high-temperature reactors (FHRs) with solid fuel and clean salt coolants, molten salt reactors (MSRs) with fuel dissolved in the salt coolant and salt-cooled fusion machines. Open Brayton combined cycles allow the use of natural gas, hydrogen, other fuels and firebrick heat storage for peak electricity production with incremental heat-to-electricity efficiencies from 66 to 70+% efficient. There are closed Brayton cycle options that use firebrick heat storage but these have not been investigated in any detail. Many of these cycles couple to high-temperature gas-cooled reactors (HTGRs). (author)

  5. Influences of biomass heat and biochemical energy storages on the land surface fluxes and radiative temperature

    Science.gov (United States)

    Gu, Lianhong; Meyers, Tilden; Pallardy, Stephen G.; Hanson, Paul J.; Yang, Bai; Heuer, Mark; Hosman, Kevin P.; Liu, Qing; Riggs, Jeffery S.; Sluss, Dan; Wullschleger, Stan D.

    2007-01-01

    The interest of this study was to develop an initial assessment on the potential importance of biomass heat and biochemical energy storages for land-atmosphere interactions, an issue that has been largely neglected so far. We conducted flux tower observations and model simulations at a temperate deciduous forest site in central Missouri in the summer of 2004. The model used was the comprehensive terrestrial ecosystem Fluxes and Pools Integrated Simulator (FAPIS). We first examined FAPIS performance by testing its predictions with and without the representation of biomass energy storages against measurements of surface energy and CO2 fluxes. We then evaluated the magnitudes and temporal patterns of the biomass energy storages calculated by FAPIS. Finally, the effects of biomass energy storages on land-atmosphere exchanges of sensible and latent heat fluxes and variations of land surface radiative temperature were investigated by contrasting FAPIS simulations with and without these storage terms. We found that with the representation of the two biomass energy storage terms, FAPIS predictions agreed with flux tower measurements fairly well; without the representation, however, FAPIS performance deteriorated for all predicted surface energy flux terms although the effect on the predicted CO2 flux was minimal. In addition, we found that the biomass heat storage and biochemical energy storage had clear diurnal patterns with typical ranges from -50 to 50 and -3 to 20 W m-2, respectively; these typical ranges were exceeded substantially when there were sudden changes in atmospheric conditions. Furthermore, FAPIS simulations without the energy storages produced larger sensible and latent heat fluxes during the day but smaller fluxes (more negative values) at night as compared with simulations with the energy storages. Similarly, without-storage simulations had higher surface radiative temperature during the day but lower radiative temperature at night, indicating that the

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

    Science.gov (United States)

    Offenhartz, P. O.

    1981-03-01

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

  7. Development of a revolving drum reactor for open-sorption heat storage processes

    International Nuclear Information System (INIS)

    Zettl, Bernhard; Englmair, Gerald; Steinmaurer, Gerald

    2014-01-01

    To evaluate the potential of an open sorption storage process using molecular sieves to provide thermal energy for space heating and hot water, an experimental study of adsorption heat generation in a rotating reactor is presented. Dehydrated zeolite of the type 4A and MSX were used in form of spherical grains and humidified room air was blown through the rotating bed. Zeolite batches of about 50 kg were able to generate an adsorption heat up to 12 kWh and temperature shifts of the process air up to 36 K depending on the inlet air water content and the state of dehydration of the storage materials. A detailed study of the heat transfer effects, the generated adsorption heat, and the evolving temperatures show the applicability of the reactor and storage concept. - Highlights: • Use of an open adsorption concept for domestic heat supply was proved. • A rotating heat drum reactor concept was successfully applied. • Zeolite batches of 50 kg generated up to 12 kWh adsorption heat (580 kJ/kg). • Temperature shift in the rotating material bed was up to 60 K during adsorption

  8. PBMR spent fuel bulk dry storage heat removal - HTR2008-58170

    International Nuclear Information System (INIS)

    De Wet, G. J.; Dent, C.

    2008-01-01

    A low decay heat (implying Spent Fuel (SF) pebbles older than 8-9 years) bulk dry storage section is proposed to supplement a 12-tank wet storage section. Decay heat removal by passive means must be guaranteed, taking into account the fact that dry storage vessels are under ground and inside the building footprint. Cooling takes place when ambient air (drawn downwards from ground level) passes on the outside of the 6 tanks' vessel containment (and gamma shielding), which is in a separate room inside the building, but outside PBMR building confinement and open to atmosphere. Access for loading/unloading of SF pebbles is only from the top of a tank, which is inside PBMR building confinement. No radioactive substances can therefore leak into atmosphere, as vessel design will take into account corrosion allowance. In this paper, it is shown (using CFD (Computational Fluid Dynamics) modelling and analytical analyses) that natural convection and draught induced flow combine to remove decay heat in a self-sustaining process. Decay heat is the energy source, which powers the draught inducing capability of the dry storage modular cell system: the more decay heat, the bigger the drive to expel heated air through a higher outlet and entrain cool ambient air from ground level to the bottom of the modular cell. (authors)

  9. Organic Rankine Cycle with Solar Heat Storage in Paraffin Way

    Directory of Open Access Journals (Sweden)

    Constantin LUCA

    2015-06-01

    Full Text Available The paper presents an electricity generation system based on an Organic Rankine Cycle and proposed storing the amount of the heat produced by the solar panels using large volume of paraffin wax. The proposed working fluid is R-134a refrigerant. The cycle operates at very low temperatures. A efficiency of 6,55% was obtained.

  10. Development of evaluation method for heat removal design of dry storage facilities. Pt. 4. Numerical analysis on vault storage system of cross flow type

    International Nuclear Information System (INIS)

    Sakamoto, Kazuaki; Hattori, Yasuo; Koga, Tomonari; Wataru, Masumi

    1999-01-01

    On the basis of the result of the heat removal test on vault storage system of cross flow type using the 1/5 scale model, an evaluation method for the heat removal design was established. It was composed of the numerical analysis for the convection phenomena of air flow inside the whole facility and that for the natural convection and the detailed turbulent mechanism near the surface of the storage tube. In the former analysis, air temperature distribution in the storage area obtained by the calculation gave good agreement within ±3degC with the test result. And fine turbulence models were introduced in the latter analysis to predict the separation flow in the boundary layer near the surface of the storage tube and the buoyant flow generated by the heat from the storage tube. Furthermore, the properties of removing the heat in a designed full-scale storage facility, such as flow pattern in the storage area, temperature and heat transfer rate of the storage tubes, were evaluated by using each of three methods, which were the established numerical analysis method, the experimental formula demonstrated in the heat removal test and the conventional evaluation method applied to the past heat removal design. As a result, the safety margin and issues included in the methods were grasped, and the measures to make a design more rational were proposed. (author)

  11. Geothermal long-term modelling of a solar coupled geothermal probe heat storage in Crailsheim; Geothermische Langzeitmodellierung eines solargekoppelten Erdsonden-Waermespeichers in Crailsheim

    Energy Technology Data Exchange (ETDEWEB)

    Homuth, Sebastian; Mikisek, Philipp; Goetz, Annette E.; Sass, Ingo [Technische Univ. Darmstadt (Germany). Fachgebiet Angewandte Geothermie

    2011-10-24

    The thermal variations of the subsurface in the vicinity of a seasonal solar coupled geothermal probe heat storage were modeled using FEFLOW {sup registered} over a period of thirty years. The geothermal probe heat storage consists of eighty boreholes in an area of 85 square meters. The geothermal probes have a depth of 55 m and are mainly located in limestones of the Upper Muschelkalk (Triassic). The geothermal probe heat storage is thermally loaded from April to September. The thermal discharge takes place from October to March. The thermal and hydraulic input data of the model are based on three 80 meter deep geothermal probes (GWM 1-3) in the vicinity of the storage. The cores were completely lithologically, facially and finely stratigraphically affiliated. Measurements of thermal conductivity, permeability, porosity and density of 76 representative samples from the geothermal probe GWM 3 and measurements of the main fracture directions in two reference digestions at Crailsheim enabled a most realistic modeling of the storage. The results of the long-term modeling can be used for a detailed forecasting of the thermal alterations in the subsurface.

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

    DEFF Research Database (Denmark)

    Mathiesen, Brian Vad; Lund, Henrik

    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 the need for ancillary services. Devices to store electricity as well as devices to store heat can be used to help the integration of fluctuating sources. Electricity storage technologies can be used...... to relocate electricity production directly from the sources, while heat storage devices can be used to relocate the electricity production from CHP plants and hereby improve the ability to integrate RES. The analyses are done by advanced computer modelling and the results are given as diagrams showing...

  13. Domestic demand-side management (DSM): Role of heat pumps and thermal energy storage (TES) systems

    International Nuclear Information System (INIS)

    Arteconi, A.; Hewitt, N.J.; Polonara, F.

    2013-01-01

    Heat pumps are seen as a promising technology for load management in the built environment, in combination with the smart grid concept. They can be coupled with thermal energy storage (TES) systems to shift electrical loads from high-peak to off-peak hours, thus serving as a powerful tool in demand-side management (DSM). This paper analyzes heat pumps with radiators or underfloor heating distribution systems coupled with TES with a view to showing how a heat pump system behaves and how it influences the building occupants' thermal comfort under a DSM strategy designed to flatten the shape of the electricity load curve by switching off the heat pump during peak hours (16:00–19:00). The reference scenario for the analysis was Northern Ireland (UK). The results showed that the heat pump is a good tool for the purposes of DSM, also thanks to the use of TES systems, in particular with heating distribution systems that have a low thermal inertia, e.g. radiators. It proved possible to achieve a good control of the indoor temperature, even if the heat pump was turned off for 3 h, and to reduce the electricity bill if a “time of use” tariff structure was adopted. -- Highlights: ► Heat pump heating systems with thermal energy storage are considered. ► System behavior is investigated during a DSM strategy for reducing peak energy demand. ► Heat pump heating systems demonstrate to be able to have an active role in DSM programs. ► A TES system must be coupled with the heat pump in presence of low thermal inertia heating distribution systems. ► Central role played by incentives schemes to promote this technology

  14. Calculation method for the seasonal performance of heat pump compact units and validation. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Wemhoener, C.; Dott, R.; Afjei, Th. [University of Applied Sciences Northwestern Switzerland, Institute of Energy in Buildings, Muttenz (Switzerland); Huber, H.; Helfenfinger, D.; Keller, P.; Furter, R. [University of Applied Sciences Lucerne (HTA), Test center HLKS, Horw (Switzerland)

    2007-02-15

    This comprehensive final report for the Swiss Federal Office of Energy (SFOE) takes a look at compact heat pump units that have been developed for the heating of low energy consumption houses built to MINERGIE or MINERGIE-P standards. These units, which combine the functions of space heating, domestic hot water preparation and ventilation in one unit are described. A testing procedure developed at the University of Applied Science in Lucerne, Switzerland, using a test rig for the measurement of the seasonal performance factor (SPF) is described. A calculation method based on temperature classes for the calculation of the SPF of combined heat pump systems for space heating and domestic hot water preparation that was developed by the Institute of Energy in Buildings at the University of Applied Sciences Northwestern Switzerland is examined. Two pilot plants allowing detailed field monitoring of two compact units are described. One pilot plant installed in a single-family house built to MINERGIE standard in Gelterkinden, Switzerland, provided data on a compact unit. These results of measurements made on this and a further installation in a MINERGIE-P ultra-low energy consumption house in Zeiningen, Switzerland, are presented and discussed. Calculation methods, including exergy considerations are reviewed and their validation is discussed.

  15. [Seasonal variation of soil heat conduction in a larch plantation and its relations to environmental factors].

    Science.gov (United States)

    Wang, Wen-Jie; Cui, Song; Liu, Wei; Zu, Yuan-Gang; Sun, Wei; Wang, Hui-Min

    2008-10-01

    Based on a 3-year (2003-2005) observation of soil heat flux (SHF) in a larch (Larix gmelinii) plantation, the characteristics of soil heat conduction in the plantation and their relationships with environment factors were analyzed. The results showed that there was an obvious seasonal variation of SHF in different years and sampling sites. The SHF was positive from April to August and mostly negative from September to next March, with an almost balance between heat income and outcome at annual scale. Solar net radiation had significant effects on the SHF and soil heat conductance (k), and an obvious time-lag effect was found, with 4-5 hours' time-lag in winter and 2-3 hours' time-lag in summer. Based on the real-time measurement of SHF and soil temperature difference at the study sites, the k value was significantly higher in early spring (P 0.05). Therefore, when we use the observation data of soil temperature from weather stations to estimate soil heat flux, the k value in spring (from March to May) could induce a bias estimation.

  16. Theoretical evaluation on the impact of heat exchanger in Advanced Adiabatic Compressed Air Energy Storage system

    International Nuclear Information System (INIS)

    Yang, Ke; Zhang, Yuan; Li, Xuemei; Xu, Jianzhong

    2014-01-01

    Highlights: • A multi-stage AA-CAES system model is established based on thermodynamic theory. • Four Cases about pressure loss and effectiveness of heat exchanger are investigated. • The impact of pressure loss on conversion of heat energy in TES is more sensitive. • The impact of heat exchanger effectiveness in charge process on system is stronger. • Pressure loss in heat exchanger affects the change trends of system efficiency. - Abstract: Advanced Adiabatic Compressed Air Energy Storage (AA-CAES) is a large-scale energy storage system based on gas turbine technology and thermal energy storage (TES). Electrical energy can be converted into internal energy of air and heat energy in TES during the charge process, while reverse energy conversion proceeds during discharge process. The performance of AA-CAES system requires further improvement in order to increase efficiency. In this paper, a multi-stage AA-CAES system model is established, and the influence of effectiveness and pressure loss in heat exchanger on energy conversion and utilization efficiency of AA-CAES system is analyzed theoretically based on the theory of thermodynamics. Four Cases about effectiveness and pressure loss of heat exchanger are investigated and compared with each other. It is found that effectiveness and pressure loss of heat exchanger are directly related to energy conversion and utilization in AA-CAES system. System efficiency changes with the variation of heat exchanger effectiveness and the impact of pressure loss on conversion of heat energy in TES is more sensitive than that of internal energy of air. Pressure loss can cause the complexity of system efficiency change. With appropriate selection of the values of heat exchanger effectiveness for both charge and discharge processes, an AA-CAES system with a higher efficiency could be expected

  17. Temperature dependency of the thermal conductivity of porous heat storage media

    Science.gov (United States)

    Hailemariam, Henok; Wuttke, Frank

    2018-04-01

    Analyzing the variation of thermal conductivity with temperature is vital in the design and assessment of the efficiency of sensible heat storage systems. In this study, the temperature variation of the thermal conductivity of a commercial cement-based porous heat storage material named - Füllbinder L is analyzed in saturated condition in the temperature range between 20 to 70°C (water based storage) with a steady state thermal conductivity and diffusivity meter. A considerable decrease in the thermal conductivity of the saturated sensible heat storage material upon increase in temperature is obtained, resulting in a significant loss of system efficiency and slower loading/un-loading rates, which when unaccounted for can lead to the under-designing of such systems. Furthermore, a new empirical prediction model for the estimation of thermal conductivity of cement-based porous sensible heat storage materials and naturally occurring crystalline rock formations as a function of temperature is proposed. The results of the model prediction are compared with the experimental results with satisfactory results.

  18. Durability of a fin-tube latent heat storage using high density polyethylene as PCM

    Science.gov (United States)

    Zauner, Christoph; Hengstberger, Florian; Etzel, Mark; Lager, Daniel; Hofmann, Rene; Walter, Heimo

    2017-10-01

    Polymers have rarely been used as storage materials in latent heat storages up to now. Thus, we systematically screened all polymers available on a large-scale, selected promising ones based on their theoretical properties and experimentally tested more than 50 candidates. We found that polyethylene, polyoxymethylene and polyamides are promising even as recycled material. Especially high density polyethylene (HDPE) turned out to be suitable as was shown by detailed thermophysical characterization including more than 1000 heating and cooling cycles for INEOS Rigidex HD6070EA. We built a storage with 170 kg HDPE and a total mass of 600 kg based on a fin-tube heat exchanger and characterized its energy capacity, power characteristics and temperature profiles using a thermal oil test rig. In total we performed 30 melting and crystallization cycles where the whole storage was above 100 °C for more than 140 hours. After usage we examined the interior of the storage by cutting it into various pieces. A thin layer of degradation was observed on the surfaces of the PCM which is most likely related to thermo-oxidative degeneration of HDPE. However, the bulk of the PCM is still intact as well as the heat exchanger itself.

  19. Demand management of city gas per season and study of estimating proper size of LNG storage facilities

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Y.H.; Kim, S.D. [Korea Energy Economics Institute, Euiwang (Korea, Republic of)

    1997-09-01

    LNG storage facilities are indispensable to satisfy demand throughout the year by saturating the time difference of supply and demand that appears due to seasonal factors. The necessity of storage facilities is more important in a country like Korea where LNG is not produced at all and imports are relied upon. The problem of deciding how much storage facilities to keep and in what pattern to import LNG is a question to solve in order to minimize the costs related to the construction of LNG storage facilities while not causing any problem in the supply and demand of LNG. This study analyzes how the import of LNG and the consumption pattern of LNG for power generation affect the decision on the size of storage facilities. How the shipping control, and how LNG demand for power generation affect the decision of requirement of storage facilities, and why the possibility of shipping control should be investigated in the aspect of costs is investigated. As a result of this study, I presented necessary basic data for drafting a policy by assessing the minimum requirements of storage facilities needed for balancing the supply and demand with the various shipping control and LNG consumption patterns through simulation up to the year 2010. 10 refs., 33 figs., 66 tabs.

  20. Adaptive heat pump and battery storage demand side energy management

    Science.gov (United States)

    Sobieczky, Florian; Lettner, Christian; Natschläger, Thomas; Traxler, Patrick

    2017-11-01

    An adaptive linear model predictive control strategy is introduced for the problem of demand side energy management, involving a photovoltaic device, a battery, and a heat pump. Moreover, the heating influence of solar radiation via the glass house effect is considered. Global sunlight radiation intensity and the outside temperature are updated by weather forecast data. The identification is carried out after adapting to a time frame witch sufficiently homogeneous weather. In this way, in spite of the linearity an increase in precision and cost reduction of up to 46% is achieved. It is validated for an open and closed loop version of the MPC problem using real data of the ambient temperature and the global radiation.

  1. Smart solar tanks - Heat storage of the future?

    DEFF Research Database (Denmark)

    Furbo, Simon; Shah, Louise Jivan

    1997-01-01

    energy supply system to a required temperature in periods with hot water demand. The tank is heated by the auxiliary energy supply system from the top so that the volume of water heated to the required temperature can be controlled in a flexible way. In periods with a large hot water demand the volume...... can be large and in periods with a small hot water demand the volume can be small. For instance, the energy supply system can be controlled on measurements of the energy content of the tank during all hours of the week and based on a required hot water consumption and consumption pattern which can...... recommendations for future development work are given....

  2. Thermal energy storage for electricity-driven space heating in a day-ahead electricity market

    DEFF Research Database (Denmark)

    Pensini, Alessandro

    2012-01-01

    Thermal Energy Storage (TES) in a space heating (SH) application was investigated. The study aimed to determine the economic benefits of introducing TES into an electricity-driven SH system under a day-ahead electricity market. The performance of the TES was assessed by comparing the cost...... of electricity in a system with a TES unit to the case where no storage is in use and the entire heat requirement is fulfilled by purchasing electricity according to the actual load. The study had two goals: 1. Determining how the size – in terms of electricity input (Pmax) and energy capacity (Emax...

  3. Compressed air energy storage with waste heat export: An Alberta case study

    International Nuclear Information System (INIS)

    Safaei, Hossein; Keith, David W.

    2014-01-01

    Highlights: • Export of compression waste heat from CAES facilities for municipal heating can be profitable. • D-CAES concept has a negative abatement cost of −$40/tCO 2 e under the studied circumstances. • Economic viability of D-CAES highly depends on distance between air storage site and heat load. - Abstract: Interest in compressed air energy storage (CAES) technology has been renewed driven by the need to manage variability form rapidly growing wind and solar capacity. Distributed CAES (D-CAES) design aims to improve the efficiency of conventional CAES through locating the compressor near concentrated heating loads so capturing additional revenue through sales of compression waste heat. A pipeline transports compressed air to the storage facility and expander, co-located at some distance from the compressor. The economics of CAES are strongly dependant on electricity and gas markets in which they are embedded. As a case study, we evaluated the economics of two hypothetical merchant CAES and D-CAES facilities performing energy arbitrage in Alberta, Canada using market data from 2002 to 2011. The annual profit of the D-CAES plant was $1.3 million more on average at a distance of 50 km between the heat load and air storage sites. Superior economic and environmental performance of D-CAES led to a negative abatement cost of −$40/tCO 2 e. We performed a suite of sensitivity analyses to evaluate the impact of size of heat load, size of air storage, ratio of expander to compressor size, and length of pipeline on the economic feasibility of D-CAES

  4. Do encapsulated heat storage materials really retain their original thermal properties?

    Science.gov (United States)

    Chaiyasat, Preeyaporn; Noppalit, Sayrung; Okubo, Masayoshi; Chaiyasat, Amorn

    2015-01-14

    The encapsulation of Rubitherm®27 (RT27), which is one of the most common commercially supplied heat storage materials, by polystyrene (PS), polydivinyl benzene (PDVB) and polymethyl methacrylate (PMMA) was carried out using conventional radical microsuspension polymerization. The products were purified to remove free RT27 and free polymer particles without RT27. In the cases of PS and PDVB microcapsules, the latent heats of melting and crystallization for RT27 ( and , J/g-RT27) were clearly decreased by the encapsulation. On the other hand, those of the PMMA microcapsules were the same as pure RT27. A supercooling phenomenon was observed not only for PS and PDVB but also for the PMMA microcapsules. These results indicate that the thermal properties of the heat storage materials encapsulated depend on the type of polymer shells, i.e., encapsulation by polymer shell changes the thermal properties of RT27. This is quite different from the idea of other groups in the world, in which they discussed the thermal properties based on the ΔHm and ΔHc values expressed in J/g-capsule, assuming that the thermal properties of the heat storage materials are not changed by the encapsulation. Hereafter, this report should raise an alarm concerning the "wrong" common knowledge behind developing the encapsulation technology of heat storage materials.

  5. Evaluation of a ground thermal energy storage system for heating and cooling of an existing dwelling

    Energy Technology Data Exchange (ETDEWEB)

    Leong, W.H; Lawrence, C.J. [Ryerson Polytechnic Univ., Toronto, ON (Canada). Dept. of Mechanical and Industrial Engineering; Tarnawski, V.R. [Saint Mary' s Univ., Halifax, NS (Canada). Dept. of Engineering; Rosen, M.A. [University of Ontario Institute of Technology, Oshawa, ON (Canada). Faculty of Engineering and Applied Science

    2006-07-01

    A ground-coupled heat pump (GCHP) system for heating and cooling a residential house in Ontario was simulated. The system uses the surface ground as a thermal energy storage for storing thermal energy in the summer for later use in the winter. In the summer, the ground receives both solar energy and the heat rejected by the system during cooling operation. The relationship between a heat pump and the ground is a ground heat exchanger (GHE). This presentation described the vertical and horizontal configurations of the GHE, which are the 2 basic configurations. It also described the modelling and analysis of the GCHP system. The modelling involved both simplified and comprehensive models. The simplified models of heating and cooling loads of a building, a heat pump unit, and heat transfer at the ground heat exchanger provided a direct link to the comprehensive model of heat and moisture transfer in the ground, based on the finite element method. This combination of models provided an accurate and practical simulation tool for GCHP systems. The energy analysis was used to evaluate the performance of the system. The use of a horizontal ground heat exchanging pipe and the impact of heat deposition and extraction through it in the ground were also studied with reference to the length of pipe, depth of pipe and layout of the pipe loop. The objective of the analysis was to find ways to optimize the thermal performance of the system and environmental sustainability of the ground. 14 refs., 3 tabs., 5 figs.

  6. Latent heat increases storage capacity. Heat transport by truck; Latente warmte vergroot opslagcapaciteit. Warmtetransport per vrachtauto is soms heel slim

    Energy Technology Data Exchange (ETDEWEB)

    De Jong, K.

    2012-11-15

    The project-group Biomass CHP (combined production of heat and power) organized a tour with a workshop in Dortmund, Germany, September 26, 2012, on storage and transport of heat and biogas. There are several projects in Germany involving road transport of heat by means of containers. A swimming pool in Dortmund already is using this option since 2008. Waste heat from a CHP-installation for landfill gas is collected from a waste dump [Dutch] De projectgroep Biomassa en WKK organiseerde 26 September een excursie met workshop in Dortmund over opslag en transport van warmte en biogas. Er zijn in Duitsland al meerdere projecten waarbij warmte per container over de weg wordt vervoerd. Een Dortmunds zwembad werkt hier al sinds 2008 mee. De restwarmte van een wkk op stortgas wordt opgehaald bij een afvalstortplaats.

  7. Solar heating and cooling system with absorption chiller and low temperature latent heat storage: Energetic performance and operational experience

    Energy Technology Data Exchange (ETDEWEB)

    Helm, M.; Keil, C.; Hiebler, S.; Mehling, H.; Schweigler, C. [Bavarian Center for Applied Energy Research (ZAE Bayern) (Germany)

    2009-06-15

    Absorption cooling systems based on water/lithium bromide (LiBr) solution typically require an open wet cooling tower to transfer the reject heat to the ambient. Yet, water consumption, the need for water make-up and cleaning, formation of fog, and the risk of Legionella bacteria growth are hindering factors for the implementation of small solar cooling systems. The application of a latent heat storage supporting the heat rejection of the absorption chiller in conjunction with a dry cooling system allows eliminating the wet cooling tower. By that means heat rejection of the chiller is shifted to periods with lower ambient temperatures, i.e. night time or off-peak hours. The system concept and the hydraulic scheme together with an analysis of the energetic performance of the system are presented, followed by a report on the operation of a first pilot installation. (author)

  8. NUMERICAL ANALYSIS OF HEAT STORAGE OF SOLAR HEAT IN FLOOR CONSTRUCTION

    DEFF Research Database (Denmark)

    Weitzmann, Peter; Holck, Ole; Svendsen, Svend

    2003-01-01

    with the highest energy con-sumption. The reduction depends on the solar collector area, distribution of the insulation thickness, heat-ing demand and control strategy, but not on pipe spacing and layer thickness and material. Finally, it is shown that the system can also be used for comfort heating of tiled...

  9. Dynamic modeling of а heating system using geothermal energy and storage tank

    Directory of Open Access Journals (Sweden)

    Milanović Predrag D.

    2012-01-01

    Full Text Available This paper analyzes a greenhouse heating system using geothermal energy and storage tank and the possibility of utilization of insufficient amount of heat from geothermal sources during the periods with low outside air temperatures. Crucial for these analyses is modelling of the necessary yearly energy requirements for greenhouse heating. The results of these analyses enable calculation of an appropriate storage tank capacity so that the energy efficiency of greenhouse heating system with geothermal energy could be significantly improved. [Acknowledgement. This work was supported by Ministry of Science and Technology Development of the Republic of Serbia through the National Energy Efficiency Program (Grant 18234 A. The authors are thankful to the stuff and management of the Company “Farmakom MB PIK 7. juli - Debrc” for their assistance during the realization of this project.

  10. Thermal storage in a heat pump heated living room floor for urban district power balancing - effects on thermal comfort, energy loss and costs for residents

    NARCIS (Netherlands)

    van Leeuwen, Richard Pieter; de Wit, J.B.; Fink, J.; Smit, Gerardus Johannes Maria

    2014-01-01

    For the Dutch smart grid demonstration project Meppelenergie, the effects of controlled thermal energy storage within the floor heating structure of a living room by a heat pump are investigated. Storage possibilities are constrained by room operative and floor temperatures. Simulations indicate

  11. Mathematical Simulation of Convective Heat Transfer in the Low-Temperature Storage of Liquefied Natural Gas

    OpenAIRE

    Shestakov, Igor; Dolgova, Anastasia; Maksimov, Vyacheslav Ivanovich

    2015-01-01

    The article shows the results of mathematical modeling of convective heat transfer in the low-temperature storage of liquefied natural gas. Regime of natural convection in an enclosure with different intensity of the heat flux at the external borders are investigated. Was examined two-dimensional nonstationary problem within the model of Navier-Stokes in dimensionless variables “vorticity - stream function - temperature”. Distributions of hydrodynamic parameters and temperatures that characte...

  12. Analysis of the Storage Capacity in an Aggregated Heat Pump Portfolio

    DEFF Research Database (Denmark)

    Nielsen, Kirsten Mølgaard; Andersen, Palle; Pedersen, Tom Søndergård

    2015-01-01

    Energy storages connected to the power grid will be of great importance in the near future. A pilot project has investigated more than 100 single family houses with heat pumps all connected to the internet. The houses have large heat capacities and it is possible to move energy consumption to sui...... (scheduling) algorithm. The properties of this scheduling are investigated in the paper especially the flexibility and ability to trade on the intra-day regulating market is in focus....

  13. Subcooled compressed air energy storage system for coproduction of heat, cooling and electricity

    International Nuclear Information System (INIS)

    Arabkoohsar, A.; Dremark-Larsen, M.; Lorentzen, R.; Andresen, G.B.

    2017-01-01

    Highlights: •A new configuration of compressed air energy storage system is proposed and analyzed. •This system, so-called subcooled-CAES, offers cogeneration of electricity, heat and cooling. •A pseudo-dynamic energy, exergy and economic analysis of the system for an entire year is presented. •The annual power, cooling and heat efficiencies of the system are around 31%, 32% and 92%. •The overall energy and exergy performance coefficients of the system are 1.55 and 0.48, respectively. -- Abstract: Various configurations of compressed air energy storage technology have received attention over the last years due to the advantages that this technology offers relative to other power storage technologies. This work proposes a new configuration of this technology aiming at cogeneration of electricity, heat and cooling. The new system may be very advantageous for locations with high penetration of renewable energy in the electricity grid as well as high heating and cooling demands. The latter would typically be locations with district heating and cooling networks. A thorough design, sizing and thermodynamic analysis of the system for a typical wind farm with 300 MW capacity in Denmark is presented. The results show a great potential of the system to support the local district heating and cooling networks and reserve services in electricity market. The values of power-to-power, power-to-cooling and power-to-heat efficiencies of this system are 30.6%, 32.3% and 92.4%, respectively. The exergy efficiency values are 30.6%, 2.5% and 14.4% for power, cooling and heat productions. A techno-economic comparison of this system with two of the most efficient previous designs of compressed air energy storage system proves the firm superiority of the new concept.

  14. Development of a solar thermal storage system suitable for the farmhouse heating in northeast China

    Energy Technology Data Exchange (ETDEWEB)

    Jang, M.K. [Shenyang Agricultural Univ., Shenyang (China)

    2010-07-01

    This study reported on the performance of a passive solar radiant floor heating system designed for standard energy-saving farmhouses in northeast China. Weather data in the region was analyzed in terms of solar radiation, temperature, humidity and light levels. The heating characteristics of the building materials such as windows, doors, walls and roofs were also analyzed along with the indoor thermal environment of the farmhouse. The heating load was then calculated along with the size of the thermal storage element and the area of the collector element. The passive solar radiant floor heating system was designed for heating during the winter and cooling in summer. According to the results, the heating characteristics of the system have the potential to improve farming villages environment and the use of renewable energy.

  15. Thermal energy storage system using phase change materials: Constant heat source

    Directory of Open Access Journals (Sweden)

    Reddy Meenakshi R.

    2012-01-01

    Full Text Available The usage of phase change materials (PCM to store the heat in the form of latent heat is increased, because large quantity of thermal energy is stored in smaller volumes. In the present experimental investigation paraffin and stearic acid are employed as PCMs in thermal energy storage (TES system to store the heat as sensible and latent heat also. A constant heat source is used to supply heat transfer fluid (HTF at constant temperature to the TES system. In the TES system PCMs are stored in the form of spherical capsules of 38 mm diameter made of high density poly ethylene (HDPE. The results of the investigation are related to the charging time and recovery of stored energy from the TES system.

  16. Seasonal relationships between foliar moisture content, heat content and biochemistry of lodge pole pine and big sagebrush foliage

    Science.gov (United States)

    Yi Qi; Matt Jolly; Philip E. Dennison; Rachael C. Kropp

    2016-01-01

    Wildland fires propagate by liberating energy contained within living and senescent plant biomass. The maximum amount of energy that can be generated by burning a given plant part can be quantified and is generally referred to as its heat content (HC). Many studies have examined heat content of wildland fuels but studies examining the seasonal variation in foliar HC...

  17. Integration of solar heat storage in the ground floor; Bygningsintegreret varmelagring af solvarme i terraendaek

    Energy Technology Data Exchange (ETDEWEB)

    Weitzmann, P.; Holck, O.; Svendsen, S.

    2001-07-01

    In this report the thermal properties of heat storage of solar heating in floors is examined. The floor examined is built using two decks, where the lower can be used for heat storage. It is the purpose of the work that has been carried out, to be able to quantify the potential for a reduction of the heating demand in a house, through the use of heat storage of solar heating. The report starts out with an introduction to the problem that is to be examined, namely to perform detailed calculations of the temperature and heat flows in floors. A description of the theory for the implementation of the model for solar collector, solar tank, floor, foundation and control strategies, can be found. The model described here has been implemented into the programming language Matlab and Simulink. Especially the model of the floor is described in great detail. The section begins with a description of the floor construction. It is then described how the floor construction is implemented into a detailed finite element model, and converted into a less detailed RC-model, where the temperature is calculated only in a few points. Each of the points had a heat capacity, and between the points a thermal resistance is included. The reason for using a RC-model is, that it proved impossible to do yearly calculations using the finite element model because of unacceptably long calculation times. Instead the procedure for the conversion between the two models is shown. After the conversion results from the two methods are compared to estimate the error introduced by this conversion to a less detailed model. The two methods are found to differ only by around 5%. The coefficients to be used in the RC-model are shown for seven different layouts of the floor concerning pipe spacing, distribution of insulation, thickness of heat storage layer and type of heat storage layer (sand or concrete). A number of different control strategies for the distribution of flow in solar tank and heat storage

  18. Model-based assessment of the potential of seasonal aquifer thermal energy storage and recovery as a groundwater ecosystem service for the Brussels-Capital Region

    Science.gov (United States)

    Anibas, Christian; Huysmans, Marijke

    2015-04-01

    Urban areas are characterized by their concentrated demand of energy, applying a high pressure on urban ecosystems including atmosphere, soils and groundwater. In the light of global warming, urbanization and an evolving energy system, it is important to know how urbanized areas can contribute to their own energy demands. One option is to use the possibilities aquifers offer as an ecosystem service (BONTE et al., 2011). If used effectively an improvement in air and groundwater quality is achieved. Additionally, the more efficient distribution of the used energy may also lead to a decrease in primary energy consumption (ZUURBIER, 2013). Therefore, investigations of the potential of seasonal aquifer thermal energy storage and recovery (ATES) for the Brussels-Capital Region, Belgium is being conducted. The potential of ATES systems are of special interest for energy demands in high density urban areas because of such infrastructure as office buildings, schools, hospitals and shopping malls. In an open water circuit ATES systems consist of two or more groundwater wells, where in seasonal cycles one subtracts and the other recharges water to the aquifer. Heat pumps use the heat capacity of water for heating or cooling a building. An important limitation of the methodology is the quality of the groundwater used (i.e. precipitation of Fe- or Mn-oxides can decrease the yield). However, ATES systems on the other hand can also improve groundwater quality and groundwater ecosystems. The current knowledge of the potential for ATES systems in the Brussels-Capital Region is based on geological assessments from VITO (2007). The Brussels-Capital Region is divided into a western and eastern section with respect to geology. While the western part has less favorable conditions for ATES, the eastern is composed of the Brussels Sand formation, which is a 20-40 m thick aquifer layer that has the highest potential for ATES systems in the region. By applying groundwater flow and heat

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

    Science.gov (United States)

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

    1987-07-01

    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.

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

    Science.gov (United States)

    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.

  1. Evaluating work/recovery schedules in terms of whole body heat storage

    Energy Technology Data Exchange (ETDEWEB)

    Hardcastle, S.G. [Natural Resources Canada, Sudbury, ON (Canada). CANMET Mining and Mineral Sciences Laboratories; Stapleton, J.M.; Kenny, G.P. [Ottawa Univ., Ottawa, ON (Canada). School of Human Kinetics, Human and Environmental Physiology Research Unit; Allen, C. [Vale Inco, Copper Cliff, ON (Canada)

    2010-07-01

    This paper reported on heat stress related research aimed at better managing the heat exposure of underground miners. The potential for underground miners to experience heat stress or strain is increasing due to greater mining depth; mechanization, and a trend towards larger diesel equipment; an aging workforce; an increasing amount of personal protective equipment worn to prevent injuries (that has led to most of the miner's body being covered) and increases in the surface climate that are superimposed through the underground workplace. This paper focused on research involving metabolic heat storage and the possibility of heat strain from elevated core temperatures. It targeted work/recovery cycles and the recovery strategies between work bouts. The first study examined the cumulative change in body heat content for a moderate metabolic rate and increasing the recovery allocation as per the TLV screening criteria to offset an increase in the wet bulb globe temperature (WBGT). The second study examined strategies that could be used between work bouts and how they affect the thermoregulatory system, heat generation or losses and net cumulative heat storage. The calorimeter based work suggested that a miner's clothing may be improved to promote evaporative cooling, and that work recovery regimes could be modified to maximize recovery. 10 refs., 1 tab., 6 figs.

  2. Second law analysis of a diesel engine waste heat recovery with a combined sensible and latent heat storage system

    International Nuclear Information System (INIS)

    Pandiyarajan, V.; Chinnappandian, M.; Raghavan, V.; Velraj, R.

    2011-01-01

    The exhaust gas from an internal combustion engine carries away about 30% of the heat of combustion. The energy available in the exit stream of many energy conversion devices goes as waste. The major technical constraint that prevents successful implementation of waste heat recovery is due to intermittent and time mismatched demand for and availability of energy. The present work deals with the use of exergy as an efficient tool to measure the quantity and quality of energy extracted from a diesel engine and stored in a combined sensible and latent heat storage system. This analysis is utilized to identify the sources of losses in useful energy within the components of the system considered, and provides a more realistic and meaningful assessment than the conventional energy analysis. The energy and exergy balance for the overall system is quantified and illustrated using energy and exergy flow diagrams. In order to study the discharge process in a thermal storage system, an illustrative example with two different cases is considered and analyzed, to quantify the destruction of exergy associated with the discharging process. The need for promoting exergy analysis through policy decision in the context of energy and environment crisis is also emphasized. - Highlights: → WHR with TES system eliminates the mismatch between the supply of energy and demand. → A saving of 15.2% of energy and 1.6% of exergy is achieved with PCM storage. → Use of multiple PCMs with cascaded system increases energy and exergy efficiency.

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

    Science.gov (United States)

    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

  4. Heat-Related Hospitalizations in Older Adults: An Amplified Effect of the First Seasonal Heatwave

    Science.gov (United States)

    Liss, Alexander; Wu, Ruiruo; Chui, Kenneth Kwan Ho; Naumova, Elena N.

    2017-01-01

    Older adults are highly vulnerable to the detriment of extreme weather. The rapid non-linear increase in heat-related morbidity is difficult to quantify, hindering the attribution of direct effects of exposure on severe health outcomes. We examine the effects of ambient temperatures on heat-related hospitalizations (HH) among the elderly in presence of strong seasonality and by assessing the effects caused by the first and subsequent seasonal heatwaves. We empirically derived the thresholds for a heatwave episode in Boston MSA based on 16 years of daily observations. We compared the health risks of heatwaves using the proposed and four alternative definitions. 701 cases of HH in older residents of Boston area were examined using harmonic regression models, designed to capture the non-linear effects of ambient temperatures and heatwave episodes when the night-time temperature is above 65.5 °F for 3 consecutive nights. The overall relative risk of HH associated with a heatwave episode was 6.9 [95%CI:4.8-9.8]. The relative risk of HH associated with the first heatwave increases up to 13.3 [95%CI:7.4-24.0]. The risk declined to 3.7 [95%CI:2.4-5.8] for the subsequent heatwave. Four other commonly used heatwave definitions confirmed these findings. Public health actions have to target the first heatwave to maximize the impact of preventive measures.

  5. Verification of heat removal capability of a concrete cask system for spent fuel storage

    International Nuclear Information System (INIS)

    Sakai, Mikio; Fujiwara, Hiroaki; Sakaya, Tadatugu

    2001-01-01

    The reprocessing works comprising of a center of nuclear fuel cycle in Japan is now under construction at Rokkasho-mura in Aomori prefecture, which is to be operated in 2005. However, as reprocessing capacity of the works is under total forming amount of spent nuclear fuels, it has been essential to construct a new facility intermediately to store them at a period before reprocessing them because of prediction to reach limit of pool storage in nuclear power stations. There are some intermediate storage methods, which are water pool method for wet storage, and bolt method, metal cask method, silo method and concrete cask method for dry storage. Among many methods, the dry storage is focussed at a standpoint of its operability and economy, the concrete cask method which has a lot of using results in U.S.A. has been focussed as a method expectable in its cost reduction effect among it. The Ishikawajima-Harima Heavy Industries Co., Ltd. produced, in trial, a concrete cask with real size to confirm productivity when advancing design work on concrete cask. By using the trial product, a heat removal test mainly focussing temperature of concrete in the cask was carried out to confirm heat conductive performances of the cask. And, analysis of heat conductivity was also carried out to verify validity of its analysis model. (G.K.)

  6. Investigation of Stratified Thermal Storage Tank Performance for Heating and Cooling Applications

    Directory of Open Access Journals (Sweden)

    Azharul Karim

    2018-04-01

    Full Text Available A large amount of energy is consumed by heating and cooling systems to provide comfort conditions for commercial building occupants, which generally contribute to peak electricity demands. Thermal storage tanks in HVAC systems, which store heating/cooling energy in the off-peak period for use in the peak period, can be used to offset peak time energy demand. In this study, a theoretical investigation on stratified thermal storage systems is performed to determine the factors that significantly influence the thermal performance of these systems for both heating and cooling applications. Five fully-insulated storage tank geometries, using water as the storage medium, were simulated to determine the effects of water inlet velocity, tank aspect ratio and temperature difference between charging (inlet and the tank water on mixing and thermocline formation. Results indicate that thermal stratification enhances with increased temperature difference, lower inlet velocities and higher aspect ratios. It was also found that mixing increased by 303% when the temperature difference between the tank and inlet water was reduced from 80 °C to 10 °C, while decreasing the aspect ratio from 3.8 to 1.0 increased mixing by 143%. On the other hand, increasing the inlet water velocity significantly increased the storage mixing. A new theoretical relationship between the inlet water velocity and thermocline formation has been developed. It was also found that inlet flow rates can be increased, without increasing the mixing, after the formation of the thermocline.

  7. Basic study on solar heat storage based on concentration difference

    Energy Technology Data Exchange (ETDEWEB)

    Fujii, Ishine; Higuchi, Akon; Ohashi, Yoshiaki

    1986-12-01

    An experimental study is performed for water solution of calcium chloride, a suitable solution for the captioned subject, and the condensation of the solution using hydrophobic film comparing to the semipermeable membrane. The relationship between saturated steam pressure and temperature, in regard to a water solution of 30-50 wt percent is clarified after testing the effect of solution concentration to the increase of boiling point. Next, the state of precipitated solute is examined as a possible problem to encounter during film condensation. The experiment reveals that solidification heat is instantaneously evolved when the solute is precipitated. Performance characteristics of the hydrophobic film are tested with a cylindrical water solution tank in which a PTFE porous film of 0.6 Mum hole diameter is sandwitched at one end. Test result reveals relationships between solution temperature, surface temperature in the steam side of the cooling plate and the quantity of condensed liquid in transmitted steam. (5 refs, 6 figs, 2 tabs)

  8. Influence of red wine pomace seasoning and high-oxygen atmosphere storage on carcinogens formation in barbecued beef patties.

    Science.gov (United States)

    García-Lomillo, Javier; Viegas, Olga; Gonzalez-SanJose, Maria L; Ferreira, Isabel M P L V O

    2017-03-01

    Polycyclic aromatic hydrocarbons (PAHs) and heterocyclic aromatic amines (HAs) are carcinogenic compounds formed in barbecued meat. Conditions that reduce their formation are of major interest. This study aims to evaluate the influence of red wine pomace seasoning (RWPS) and high-oxygen atmosphere storage on the formation of PAHs and HAs in barbecued beef patties. In general, the levels of PAHs and HAs quantified were low. The storage (9days) promoted higher formation of PAHs in control patties without increase of HAs. RWPS patties cooked at preparation day presented higher levels of PAHs and HAs than control. Nevertheless, RWPS patties cooked after storage presented lower levels of PAHs and HAs than control. ABTS assay pointed out that higher radical scavenging activity may be related to with lower PAHs or HAs formation. In conclusion, RWPS can be an interesting ingredient to inhibit the formation of cooking carcinogens in barbecued patties stored at high-oxygen atmosphere. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Modeling and Control of Heat Networks With Storage : The Single-Producer Multiple-Consumer Case

    NARCIS (Netherlands)

    Scholten, Tjardo; De Persis, Claudio; Tesi, Pietro

    In heat networks, energy storage in the form of hot water in a tank is a viable approach to balancing supply and demand. In order to store a desired amount of energy, both the volume and temperature of the water in the tank need to converge to desired setpoints. To this end, we provide a provably

  10. Dynamics of water transport and storage in conifers studied with deuterium and heat tracing techniques.

    Science.gov (United States)

    F.C. Meinzer; J.R. Brooks; J.-C. Domec; B.L. Gartner; J.M. Warren; D.R. Woodruff; K. Bible; D.C. Shaw

    2006-01-01

    The volume and complexity of their vascular systems make the dynamics of tong-distance water transport in large trees difficult to study. We used heat and deuterated water (D20) as tracers to characterize whole-tree water transport and storage properties in individual trees belonging to the coniferous species Pseudotsuga menziesii...

  11. A predictive model for smart control of a domestic heat pump and thermal storage

    NARCIS (Netherlands)

    van Leeuwen, Richard Pieter; Gebhardt, I.; de Wit, J.B.; Smit, Gerardus Johannes Maria

    The purpose of this paper is to develop and validate a predictive model of a thermal storage which is charged by a heat pump and used for domestic hot water supply. The model is used for smart grid control purposes and requires measurement signals of flow and temperature at the inlet and outlet of

  12. Latent heat storage by silica-coated polymer beads containing organic phase change materials

    Czech Academy of Sciences Publication Activity Database

    Feczkó, T.; Trif, L.; Horák, Daniel

    2016-01-01

    Roč. 132, July (2016), s. 405-414 ISSN 0038-092X R&D Projects: GA MŠk(CZ) LH14318 Institutional support: RVO:61389013 Keywords : latent heat storage * phase change materials * porous beads by suspension polymerization Subject RIV: CD - Macromolecular Chemistry Impact factor: 4.018, year: 2016

  13. Experimental investigations on prototype heat storage units utilizing stable supercooling of sodium acetate trihydrate mixtures

    DEFF Research Database (Denmark)

    Dannemand, Mark; Dragsted, Janne; Fan, Jianhua

    2016-01-01

    Laboratory tests of two heat storage units based on the principle of stable supercooling of sodium acetate trihydrate (SAT) mixtures were carried out. One unit was filled with 199.5 kg of SAT with 9% extra water to avoid phase separation of the incongruently melting salt hydrate. The other unit...

  14. The use of solar energy for heating an asphalt storage tank.

    Science.gov (United States)

    1984-01-01

    10,000 gal. asphalt storage tank was equipped with a solar heating system and instrumented to determine its effectiveness over a 12.5-month period. An evaluation of the data indicated that the solar system conserved 25,126 kWh of electrical power dur...

  15. Use of infrared thermography for the evaluation of heat losses during coal storage

    NARCIS (Netherlands)

    Fierro, V.; Miranda, J.L.; Romero, C.; Andrés, J.M.; Pierrot, A.; Gómez-Landesa, E.; Arriaga, A.; Schmal, D.

    1999-01-01

    The exothermic processes during coal storage reduce the calorific value of the coal which in turn results in financial losses. An accurate and easy calculation of the losses may be an efficient tool to evaluate the effectiveness of the measures taken to reduce the spontaneous heating of coal and to

  16. heat storage in upper and lower body during high-intensity exercise ...

    African Journals Online (AJOL)

    Research on heat storage differences between the upper body and ... effects of two cooling strategies (pre-cooling and cooling during exercise) on .... Subject. Age. Height. (cm). Weight. (kg). VO2 peak l.min. -1. Body fat. (%). 1 ..... Effects of two.

  17. Increasing RES Penetration and Security of Energy Supply by Use of Energy Storages and Heat Pumps in Croatian Energy System

    DEFF Research Database (Denmark)

    Krajačić, Goran; Mathiesen, Brian Vad; Duić, Neven

    2010-01-01

    electricity, heat and transport demands, and including renewable energy, power plants, and combined heat and power production (CHP) for district heating. Using the 2007 energy system the wind power share is increased by two energy storage options: Pumped hydro and heat pumps in combination with heat storages....... The results show that such options can enable an increased penetration of wind power. Using pumped hydro storage (PHS) may increase wind power penetration from 0.5 TWh, for existing PHS installations and up to 6 TWh for very large installations. Using large heat pumps and heat storages in combination...... with specific regulation of power system could additionally increase wind penetration for 0.37 TWh. Hence, with the current technologies installed in the Croatian energy system the installed pumped hydro-plant may facilitate more than 10% wind power in the electricity system. Large-scale integration of wind...

  18. Sulfur Based Thermochemical Heat Storage for Baseload Concentrated Solar Power Generation

    Energy Technology Data Exchange (ETDEWEB)

    Wong, Bunsen [General Atomics, San Diego, CA (United States)

    2014-11-01

    This project investigates the engineering and economic feasibility of supplying baseload power using a concentrating solar power (CSP) plant integrated with sulfur based thermochemical heat storage. The technology stores high temperature solar heat in the chemical bonds of elemental sulfur. Energy is recovered as high temperature heat upon sulfur combustion. Extensive developmental and design work associated with sulfur dioxide (SO2) disproportionation and sulfuric acid (H2SO4) decomposition chemical reactions used in this technology had been carried out in the two completed phases of this project. The feasibility and economics of the proposed concept was demonstrated and determined.

  19. Dimensionless groups for multidimensional heat and mass transfer in adsorbed natural gas storage

    Energy Technology Data Exchange (ETDEWEB)

    Sphaier, L.A. [Universidade Federal Fluminense (UFF), Niteroi, RJ (Brazil). Programa de Pos-Graduacao em Engenharia Mecanica. Lab. de Mecanica Teorica e Aplicada], E-mail: lasphaier@mec.uff.br

    2010-07-01

    This paper provides a new methodology for analyzing heat and mass transfer in gas storage via adsorption. The foundation behind the proposed methodology comprises a set of physically meaningful dimensionless groups. A discussion regarding the development of such groups is herein presented, providing a fully normalized multidimensional formulation for describing the transport mechanisms involved in adsorbed gas storage. After such presentation, data from previous literature studies associated with the problem of adsorbed natural gas storage are employed for determining realistic values for the developed parameters. Then, a one-dimensional test-case problem is selected for illustrating the application of the dimensionless formulation for simulating the operation of adsorbed gas reservoirs. The test problem is focused on analyzing an adsorbed gas discharge operation. This problem is numerically solved, and the solution is verified against previously published literature data. The presented results demonstrate how a higher heat of sorption values lead to reduced discharge capacities. (author)

  20. Evaluation of an earth heat storage system in a solar energy greenhouse

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Q.; Langrell, J.; Boris, R. [Manitoba Univ., Winnipeg, MB (Canada). Dept. of Biosystems Engineering

    2010-07-01

    Greenhouses store solar energy in the walls and floors during the daytime and release the stored energy back to the greenhouse at night. In this study, an earth heat storage system was constructed and tested in a solar energy greenhouse in order to enhance energy storage. The system consisted of a network of perforated pipes buried in the soil at depths from 0.3 to 1 m. The warm air near the greenhouse ceiling was drawn to the buried pipes. Soil and air temperatures were recorded at various locations by a network of thermocouples. The energy balance was analyzed in order to evaluate the effectiveness of the earth heat storage system. The temperature profiles in the soil were used to determine the summer recharge and winter energy depletion behaviour of the system.

  1. A numerical investigation of combined heat storage and extraction in deep geothermal reservoirs

    DEFF Research Database (Denmark)

    Major, Márton; Poulsen, Søren Erbs; Balling, Niels

    2018-01-01

    Heat storage capabilities of deep sedimentary geothermal reservoirs are evaluated through numerical model simulations. We combine storage with heat extraction in a doublet well system when storage phases are restricted to summer months. The effects of stored volume and annual repetition on energy...... recovery are investigated. Recovery factors are evaluated for several different model setups and we find that storing 90 °C water at 2500 m depth is capable of reproducing, on average 67% of the stored energy. In addition, ambient reservoir temperature of 75 °C is slightly elevated leading to increased...... efficiency. Additional simulations concerning pressure build-up in the reservoir are carried out to show that safety levels may not be reached. Reservoir characteristics are inspired by Danish geothermal conditions, but results are assumed to have more general validity. Thus, deep sedimentary reservoirs...

  2. EXPERIMENTAL INVESTIGATION OF HEAT STORAGE CHARACTERISTIC OF UREA AND BORAX SALT GRADIENT SOLAR PONDS

    Directory of Open Access Journals (Sweden)

    Hüseyin KURT

    2006-03-01

    Full Text Available Salt gradient solar ponds are simple and low cost solar energy system for collecting and storing solar energy. In this study, heat storage characteristic of urea and borax solutions in the solar pond were examined experimentally. Establishing density gradients in different concentration, variations in the temperature and density profiles were observed in four different experiments. Maximum storage temperatures were measured as 28ºC and 36 ºC for the ponds with urea and borax solution, respectively. The temperature difference between the bottom and the surface of the pond were measured as 13 ºC for urea and 17 ºC for borax- solutions. According to these results, heat storage characteristic of the solar pond with borax solution was found to be better than urea solution.

  3. Performance investigation of a lab–scale latent heat storage prototype – Numerical results

    International Nuclear Information System (INIS)

    Niyas, Hakeem; Prasad, Sunku; Muthukumar, P.

    2017-01-01

    Highlights: • Developed a numerical tool for analyzing a shell-and-tube LHS system. • Effective heat capacity method is used for incorporating the latent heat. • Number of heat transfer fluid tubes and fins are optimized. • Partial charging/discharging is efficient than complete charging/discharging. • Numerically predicted values match well with the experimental results. - Abstract: In the current study, numerical analysis of the charging and discharging characteristics of a lab-scale latent heat storage (LHS) prototype is presented. A mathematical model is developed to analyze the performance characteristics of the LHS prototype of shell and tube heat exchanger configuration. Effective heat capacity (EHC) method is implemented to consider the latent heat of the phase change material (PCM) and Boussinesq approximation is used to incorporate the buoyancy effect of the molten layer of the PCM in the model. For proper modeling of velocities in the PCM, Darcy law’s source term is added. The governing equations involved in the model are solved using a finite element based software product, COMSOL Multiphysics 4.3a. The number of embedded tubes and fins on the embedded tubes are optimized based on the discharging time of the model. Various performance parameters such as charging/discharging time, energy storage/discharge rate and melt fraction are evaluated. Numerically predicted temperature variations of the model during charging and discharging processes were compared with the experimental data extracted from the lab-scale LHS prototype and a good agreement was found between them.

  4. Utilizing thermal building mass for storage in district heating systems: Combined building level simulations and system level optimization

    DEFF Research Database (Denmark)

    Dominkovic, D. F.; Gianniou, P.; Münster, M.

    2018-01-01

    on the energy supply of district heating. Results showed that longer preheating time increased the possible duration of cut-off events. System optimization showed that the thermal mass for storage was used as intra-day storage. Flexible load accounted for 5.5%–7.7% of the total district heating demand...

  5. Dynamic Heat Storage and Cooling Capacity of a Concrete Deck with PCM and Thermally Activated Building System

    DEFF Research Database (Denmark)

    Pomianowski, Michal Zbigniew; Heiselberg, Per; Jensen, Rasmus Lund

    2012-01-01

    This paper presents a heat storage and cooling concept that utilizes a phase change material (PCM) and a thermally activated building system (TABS) implemented in a hollow core concrete deck. Numerical calculations of the dynamic heat storage capacity of the hollow core concrete deck element...... in the article highlight the potential of using TABS and PCM in a prefabricated concrete deck element....

  6. Metal hydride hydrogen and heat storage systems as enabling technology for spacecraft applications

    Energy Technology Data Exchange (ETDEWEB)

    Reissner, Alexander, E-mail: reissner@fotec.at [FOTEC Forschungs- und Technologietransfer GmbH, Viktor Kaplan Straße 2, 2700 Wiener Neustadt (Austria); University of Applied Sciences Wiener Neustadt, Johannes Gutenberg-Straße 3, 2700 Wiener Neustadt (Austria); Pawelke, Roland H.; Hummel, Stefan; Cabelka, Dusan [FOTEC Forschungs- und Technologietransfer GmbH, Viktor Kaplan Straße 2, 2700 Wiener Neustadt (Austria); Gerger, Joachim [University of Applied Sciences Wiener Neustadt, Johannes Gutenberg-Straße 3, 2700 Wiener Neustadt (Austria); Farnes, Jarle, E-mail: Jarle.farnes@prototech.no [CMR Prototech AS, Fantoftvegen 38, PO Box 6034, 5892 Bergen (Norway); Vik, Arild; Wernhus, Ivar; Svendsen, Tjalve [CMR Prototech AS, Fantoftvegen 38, PO Box 6034, 5892 Bergen (Norway); Schautz, Max, E-mail: max.schautz@esa.int [European Space Agency, ESTEC – Keplerlaan 1, 2201 AZ Noordwijk Zh (Netherlands); Geneste, Xavier, E-mail: xavier.geneste@esa.int [European Space Agency, ESTEC – Keplerlaan 1, 2201 AZ Noordwijk Zh (Netherlands)

    2015-10-05

    Highlights: • A metal hydride tank concept for heat and hydrogen storage is presented. • The tank is part of a closed-loop reversible fuel cell system for space application. • For several engineering issues specific to the spacecraft application, solutions have been developed. • The effect of water contamination has been approximated for Ti-doped NaAlH{sub 4}. • A novel heat exchanger design has been realized by Selective Laser Melting. - Abstract: The next generation of telecommunication satellites will demand a platform payload performance in the range of 30+ kW within the next 10 years. At this high power output, a Regenerative Fuel Cell Systems (RFCS) offers an efficiency advantage in specific energy density over lithium ion batteries. However, a RFCS creates a substantial amount of heat (60–70 kJ per mol H{sub 2}) during fuel cell operation. This requires a thermal hardware that accounts for up to 50% of RFCS mass budget. Thus the initial advantage in specific energy density is reduced. A metal hydride tank for combined storage of heat and hydrogen in a RFCS may overcome this constraint. Being part of a consortium in an ongoing European Space Agency project, FOTEC is building a technology demonstrator for such a combined hydrogen and heat storage system.

  7. Modeling of District Heating Networks for the Purpose of Operational Optimization with Thermal Energy Storage

    Science.gov (United States)

    Leśko, Michał; Bujalski, Wojciech

    2017-12-01

    The aim of this document is to present the topic of modeling district heating systems in order to enable optimization of their operation, with special focus on thermal energy storage in the pipelines. Two mathematical models for simulation of transient behavior of district heating networks have been described, and their results have been compared in a case study. The operational optimization in a DH system, especially if this system is supplied from a combined heat and power plant, is a difficult and complicated task. Finding a global financial optimum requires considering long periods of time and including thermal energy storage possibilities into consideration. One of the most interesting options for thermal energy storage is utilization of thermal inertia of the network itself. This approach requires no additional investment, while providing significant possibilities for heat load shifting. It is not feasible to use full topological models of the networks, comprising thousands of substations and network sections, for the purpose of operational optimization with thermal energy storage, because such models require long calculation times. In order to optimize planned thermal energy storage actions, it is necessary to model the transient behavior of the network in a very simple way - allowing for fast and reliable calculations. Two approaches to building such models have been presented. Both have been tested by comparing the results of simulation of the behavior of the same network. The characteristic features, advantages and disadvantages of both kinds of models have been identified. The results can prove useful for district heating system operators in the near future.

  8. Heating with ice. Efficient heating source for heat pumps. Primary source storage. Alternative to soil sensors and soil collectors; Heizen mit Eis. Effiziente Waermequelle fuer Waermepumpen. Primaerquellenspeicher, Alternative zu Erdsonden und Erdkollektoren

    Energy Technology Data Exchange (ETDEWEB)

    Tippelt, Egbert [Viessmann, Allendorf (Germany)

    2011-12-15

    For several years heat pumps have taken up a fixed place in the mix of annually installed thermal generators. Thus, in the year 2010 every tenth newly installed heater was a heat pump. A new concept for the development and utilization of natural heat now makes this technology even more attractive. From this perspective, the author of the contribution under consideration reports on a SolarEis storage. This SolarEis storage consists of a cylindrical concrete tank with two heat exchangers consiting of plastic pipes. The SolarEis storage uses outdoor air, solar radiation and soil as heat sources for brine / water heat pumps simultaneously.

  9. Thermal performance analysis of a phase change thermal storage unit for space heating

    Energy Technology Data Exchange (ETDEWEB)

    Halawa, E.; Saman, W. [Institute for Sustainable Systems and Technologies School of Advanced Manufacturing and Mechanical Engineering, University of South Australia, Mawson Lakes SA 5095 (Australia)

    2011-01-15

    This paper presents the results of a comprehensive numerical study on the thermal performance of an air based phase change thermal storage unit (TSU) for space heating. The unit is designed for integration into space heating and cooling systems. The unit consists of a number of one dimensional phase change material (PCM) slabs contained in a rectangular duct where air passes between the slabs. The numerical analysis was based on an experimentally validated model. A parametric study has been carried out including the study on the effects of charge and discharge temperature differences, air mass flow rate, slab thicknesses, air gaps and slab dimensions on the air outlet temperatures and heat transfer rates of the thermal storage unit. The paper introduces and discusses quantities called charge and discharge temperature differences which play an important role in the melting and freezing processes. (author)

  10. Mathematical Simulation of Convective Heat Transfer in the Low-Temperature Storage of Liquefied Natural Gas

    Directory of Open Access Journals (Sweden)

    Shestakov Igor A.

    2015-01-01

    Full Text Available The article shows the results of mathematical modeling of convective heat transfer in the low-temperature storage of liquefied natural gas. Regime of natural convection in an enclosure with different intensity of the heat flux at the external borders are investigated. Was examined two-dimensional nonstationary problem within the model of Navier-Stokes in dimensionless variables “vorticity - stream function - temperature”. Distributions of hydrodynamic parameters and temperatures that characterize the basic regularities of the processes are obtained. Circulating flows are determined and carried out the analysis of vortices formation mechanism and the temperature distribution in solution at conditions of natural convection when the Grashof number (Gr = 106. A significant influence of heat transfer rate on solutions boundary on flow structure and temperature field in LNG storage tanks.

  11. High-Temperature Thermal Energy Storage for electrification and district heating

    DEFF Research Database (Denmark)

    Pedersen, A. Schrøder; Engelbrecht, K.; Soprani, S.

    stability upon thermal cycling. The most promising material consists of basalt, diabase, and magnetite, whereas the less suited rocks contain larger proportions of quartz and mica. An HT-TES system, containing 1.5 m3 of rock pieces, was constructed. The rock bed was heated to 600 ˚C using an electric heater......The present work describes development of a High Temperature Thermal Energy Storage (HT-TES) system based on rock bed technology. A selection of rocks was investigated by thermal analysis in the range 20-800 ˚C. Subsequently, a shortlist was defined primarily based on mechanical and chemical...... to simulate thermal charging from wind energy. After complete heating of the rock bed it was left fully charged for hours to simulate actual storage conditions. Subsequently the bed discharging was performed by leading cold air through the rock bed whereby the air was heated and led to an exhaust. The results...

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

    Science.gov (United States)

    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.

  13. GRACE-derived terrestrial water storage depletion associated with the 2003 European heat wave

    DEFF Research Database (Denmark)

    Andersen, Ole Baltazar; Seneviratne, S.I.; Hinderer, J.

    2005-01-01

    water storage depletion observed from GRACE can be related to the record-breaking heat wave that occurred in central Europe in 2003. We validate the measurements from GRACE using two independent hydrological estimates and direct gravity observations from superconducting gravimeters in Europe. All...... datasets agree well with the GRACE measurements despite the disparity of the employed information; the difference between datasets tends to be within GRACE margin of error. The April-to-August terrestrial water storage depletion is found to be significantly larger in 2003 than in 2002 from both models......The GRACE twin satellites reveal large inter-annual terrestrial water-storage variations between 2002 and 2003 for central Europe. GRACE observes a negative trend in regional water storage from 2002 to 2003 peaking at -7.8 cm in central Europe with an accuracy of 1 cm. The 2003 excess terrestrial...

  14. Influence of nanomaterials on properties of latent heat solar thermal energy storage materials – A review

    International Nuclear Information System (INIS)

    Raam Dheep, G.; Sreekumar, A.

    2014-01-01

    Highlights: • Classification of phase change materials. • Studies on phase change properties of various phase change materials. • Influence of nanomaterials on properties of phase change materials. - Abstract: Thermal energy storage system plays a critical role in developing an efficient solar energy device. As far as solar thermal devices are concerned, there is always a mismatch between supply and demand due to intermittent and unpredictable nature of solar radiation. A well designed thermal energy storage system is capable to alleviate this demerit by providing a constant energy delivery to the load. Many research works is being carried out to determine the suitability of thermal energy storage system to integrate with solar thermal gadgets. This review paper summarizes the numerous investigations on latent heat thermal energy storage using phase change materials (PCM) and its classification, properties, selection criteria, potential research areas and studies involved to analyze the thermal–physical properties of PCM

  15. Thermal energy storage with geothermal triplet for space heating and cooling

    Science.gov (United States)

    Bloemendal, Martin; Hartog, Niels

    2017-04-01

    Many governmental organizations and private companies have set high targets in avoiding CO2 emissions and reducing energy (Kamp, 2015; Ministry-of-Economic-affairs, 2016). ATES systems use groundwater wells to overcome the discrepancy in time between the availability of heat (during summer) and the demand for heat (during winter). Aquifer Thermal Energy Storage is an increasingly popular technique; currently over 2000 ATES systems are operational in the Netherlands (Graaf et al., 2016). High temperature ATES may help to improve performance of these conventional ATES systems. ATES systems use heat pumps to get the stored heat to the required temperature for heating of around 40-50°C and to produce the cold water for cooling in summer. These heat pumps need quite a lot of power to run; on average an ATES system produces 3-4 times less CO2 emission compared to conventional. Over 60% of those emission are accounted for by the heat pump (Dekker, 2016). This heat pump power consumption can be reduced by utilizing other sources of sustainable heat and cooling capacity for storage in the subsurface. At such operating temperatures the required storage temperatures do no longer match the return temperatures in the building systems. Therefore additional components and an additional well are required to increase the groundwater temperature in summer (e.g. solar collectors) and decrease it in winter (e.g. dry coolers). To prevent "pollution" of the warm and cold well return water from the building can be stored in a third well until weather conditions are suitable for producing the required storage temperature. Simulations and an economical evaluation show great potential for this type of aquifer thermal energy storage; economic performance is better than normal ATES while the emissions are reduce by a factor ten. At larger temperature differences, also the volume of groundwater required to pump around is much less, which causes an additional energy saving. Research now

  16. Exchanging and Storing Energy. Reducing Energy Demand through Heat Exchange between Functions and Temporary Storage

    Energy Technology Data Exchange (ETDEWEB)

    Sillem, E.

    2011-06-15

    As typical office buildings from the nineties have large heating and cooling installations to provide heat or cold wherever and whenever needed, more recent office buildings have almost no demand for heating due to high internal heat loads caused by people, lighting and office appliances and because of the great thermal qualities of the contemporary building envelope. However, these buildings still have vast cooling units to cool down servers and other energy consuming installations. At the same time other functions such as dwellings, swimming pools, sporting facilities, archives and museums still need to be heated most of the year. In the current building market there is an increasing demand for mixed-use buildings or so called hybrid buildings. The Science Business Centre is no different and houses a conference centre, offices, a museum, archives, an exhibition space and a restaurant. From the initial program brief it seemed that the building will simultaneously house functions that need cooling most of the year and functions that will need to be heated the majority of the year. Can this building be equipped with a 'micro heating and cooling network' and where necessary temporarily store energy? With this idea a research proposal was formulated. How can the demand for heating and cooling of the Science Business Centre be reduced by using energy exchange between different kinds of functions and by temporarily storing energy? In conclusion the research led to: four optimized installation concepts; short term energy storage in pavilion concept and museum; energy exchange between the restaurant and archives; energy exchange between the server space and the offices; the majority of heat and cold will be extracted from the soil (long term energy storage); the access heat will be generated by the energy roof; PV cells from the energy roof power all climate installations; a total energy plan for the Science Business Centre; a systematic approach for exchanging

  17. The largest Swiss diffusion storage system - Geology, petrophysics, hydro-geology and experience gained from the realisation of heat probes; Groesster saisonaler Diffusionsspeicher der Schweiz D4 in Root (LU): Geologie, Petrophysik, Hydrogeologie und Erfahrungen mit der Realisation des Sondenfeldes

    Energy Technology Data Exchange (ETDEWEB)

    Keller, B.

    2007-07-15

    This article takes a look at a large heat-diffusion storage system that is to be implemented in stages at a business and innovation centre in Root, near Lucerne in Switzerland. The aim is to meet 50 percent of energy needs using renewable energy. Apart from conventional oil and gas-fired systems, a combined heat and power (CHP) unit, heat and cold storage, a solar roof and photovoltaics, a seasonal underground diffusion storage system is used. This storage system is 'filled' with heat in summer from the roof and waste heat. It then functions in winter as a heat source. The system features two fields of 49, 160 metre-long heat probes that use a volume of 376,000 cubic metres of rock. The dimensioning of the rock-storage system was simulated using the PILESIM program and the first field was implemented in 2001. A geological overview is presented and the physical properties of the rock structures used are discussed. The temperature profile measured is presented and the precautions taken as a result of the possibility of meeting pockets of natural gas are discussed. Know-how gained from the implementation of the first probe field is discussed.

  18. A model predictive framework of Ground Source Heat Pump coupled with Aquifer Thermal Energy Storage System in heating and cooling equipment of a building

    NARCIS (Netherlands)

    Rostampour Samarin, V.; Bloemendal, J.M.; Keviczky, T.

    2017-01-01

    This paper presents a complete model of a building heating and cooling equipment and a ground source heat pump (GSHP) coupled with an aquifer thermal energy storage (ATES) system. This model contains detailed
    mathematical representations of building thermal dynamics, ATES system dynamics, heat

  19. Characteristics on the heat storage and recovery by the underground spiral heat exchange pipe; Chichu maisetsu spiral kan ni yoru chikunetsu shunetsu tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Imai, I [Kure National College of Technology, Hiroshima (Japan); Taga, M [Kinki University, Osaka (Japan)

    1996-10-27

    The consistency between the experimental value of a soil temperature and the calculation value of a soil temperature given by a non-steady heat conduction equation was confirmed. The experimental value is obtained by laying a spiral heat exchange pipe in the heat-insulated soil box and circulating hot water forcibly in the pipe. The temperature conductivity in soil significantly influences the heat transfer in soil. The storage performance is improved when the temperature conductivity increases because of the contained moisture. As the difference between the initial soil temperature and circulating water temperature becomes greater, the heat storage and recovery values increase. A thermal core heat transfer is done in the spiral pipe. Therefore, the diameter of the pipe little influences the heat storage performance, and the pitch influences largely. About 50 hours after heat is stored, the storage performance is almost the same as for a straight pipe that uses the spiral diameter as a pipe diameter. To obtain the same heat storage value, the spiral pipe is made of fewer materials than the straight pipe and low in price. The spiral pipe is more advantageous than the straight pipe in the necessary motive power and supply heat of a pump. 1 ref., 11 figs., 1 tab.

  20. Seasonal effects of the low-grade heat on a phytoplankton community

    International Nuclear Information System (INIS)

    McMahon, J.W.; Docherty, A.E.

    1980-06-01

    Field studies, carried out over the period 1976 March to December, examined the effects of heat-enriched cooling waters on a natural phytoplankton community. Algal concentrations, composition, species succession and carbon fixation rates were determined twice-weekly in heated and unheated (control) polyethylene enclosures located in a northern oligotrophic lake. Results were compared with data collected from the open lake. Of 31 species quantitatively studied, eleven dominant species were examined in detail. A marked response to heat enrichment by the phytoplankton occurred in the spring and was attributed to a single species of Bacillariophyceae - Synedra ulna. Species composition and seasonal succession patterns were similar in the experimental column, the control column and the lake. The relationship between production biomass quotients (P/B) and water temperature in the lake and experimental enclosure is discussed. It is suggested that thermal enrichment might be used beneficially in cold waters for enhancing biomass production of unicellular aquatic organisms. This increased availability of food, in conjuction with increased water temperatures, might then accelerate productivity of filter-feeding zooplankton and other herbivores. (auth)

  1. Analysis of an integrated packed bed thermal energy storage system for heat recovery in compressed air energy storage technology

    International Nuclear Information System (INIS)

    Ortega-Fernández, Iñigo; Zavattoni, Simone A.; Rodríguez-Aseguinolaza, Javier; D'Aguanno, Bruno; Barbato, Maurizio C.

    2017-01-01

    Highlights: •A packed bed TES system is proposed for heat recovery in CAES technology. •A CFD-based approach has been developed to evaluate the behaviour of the TES unit. •TES system enhancement and improvement alternatives are also demonstrated. •TES performance evaluated according to the first and second law of thermodynamics. -- Abstract: Compressed air energy storage (CAES) represents a very attracting option to grid electric energy storage. Although this technology is mature and well established, its overall electricity-to-electricity cycle efficiency is lower with respect to other alternatives such as pumped hydroelectric energy storage. A meager heat management strategy in the CAES technology is among the main reasons of this gap of efficiency. In current CAES plants, during the compression stage, a large amount of thermal energy is produced and wasted. On the other hand, during the electricity generation stage, an extensive heat supply is required, currently provided by burning natural gas. In this work, the coupling of both CAES stages through a thermal energy storage (TES) unit is introduced as an effective solution to achieve a noticeable increase of the overall CAES cycle efficiency. In this frame, the thermal energy produced in the compression stage is stored in a TES unit for its subsequent deployment during the expansion stage, realizing an Adiabatic-CAES plant. The present study addresses the conceptual design of a TES system based on a packed bed of gravel to be integrated in an Adiabatic-CAES plant. With this objective, a complete thermo-fluid dynamics model has been developed, including the implications derived from the TES operating under variable-pressure conditions. The formulation and treatment of the high pressure conditions were found being particularly relevant issues. Finally, the model provided a detailed performance and efficiency analysis of the TES system under charge/discharge cyclic conditions including a realistic operative

  2. Design and functionality of a segmented heat-storage prototype utilizing stable supercooling of sodium acetate trihydrate in a solar heating system

    DEFF Research Database (Denmark)

    Englmair, Gerald; Moser, Christoph; Furbo, Simon

    2018-01-01

    acetate trihydrate composites to conserve the latent heat of fusion for long-term heat storage. A control strategy directed heat from a solar collector array to either the PCM storage or a water buffer storage. Several PCM units had to be charged in parallel when the solar collector output peaked at 16 k......A solar heating system with 22.4m2 of solar collectors, a heat storage prototype consisting of four 200 kg phase-change material (PCM) storage units, and a 735 L water tank was designed to improve solar heat supply in single-family houses. The PCM storage utilized stable supercooling of sodium......W. A single unit was charged with 27.4 kWh of heat within four hours on a sunny day, and the PCM temperature increased from 20 °C to 80 °C. The sensible heat from a single PCM unit was transferred to the water tank starting with about 32 kW of thermal power after it had fully melted at 80 °C. A mechanical...

  3. Thermal Analysis of Fluidized Bed and Fixed Bed Latent Heat Thermal Storage System

    Science.gov (United States)

    Beemkumar, N.; Karthikeyan, A.; Shiva Keshava Reddy, Kota; Rajesh, Kona; Anderson, A.

    2017-05-01

    Thermal energy storage technology is essential because its stores available energy at low cost. Objective of the work is to store the thermal energy in a most efficient method. This work is deal with thermal analysis of fluidized bed and fixed bed latent heat thermal storage (LHTS) system with different encapsulation materials (aluminium, brass and copper). D-Mannitol has been used as phase change material (PCM). Encapsulation material which is in orbicular shape with 4 inch diameter and 2 mm thickness orbicular shaped product is used. Therminol-66 is used as a heat transfer fluid (HTF). Arrangement of encapsulation material is done in two ways namely fluidized bed and fixed bed thermal storage system. Comparison was made between the performance of fixed bed and fluidized bed with different encapsulation material. It is observed that from the economical point of view aluminium in fluidized bed LHTS System has highest efficiency than copper and brass. The thermal energy storage system can be analyzed with fixed bed by varying mass flow rate of oil paves a way to find effective heat energy transfer.

  4. Hot sanitary water production with CO_2 heat pumps: Effect of control strategy on system performance and stratification inside the storage tank

    International Nuclear Information System (INIS)

    Tammaro, M.; Mauro, A.W.; Montagud, C.; Corberán, J.M.; Mastrullo, R.

    2016-01-01

    In this work three different control strategies for the production of sanitary hot water by means of an electric heat pump working with CO_2 are investigated. The heat pump is a prototype, here modelled in the vapour-compression software package IMST-ART. By simulating this model, the performance of the heat pump is correlated to the boundary conditions and is scaled to different sizes, namely 1, 1.5, and 2 times larger than the reference system. After having chosen an application for which the load profile of sanitary hot water during the year is known, these heat pumps are simulated in a TRNSYS16 model where the production of sanitary hot water and the consumption are buffered by the presence of a tank. Key parameter in guaranteeing comfort and good performance of the system is the stratification inside the storage tank. The size of the tank necessary to keep a certain level of comfort at the user is then determined through a parametric analysis for each size of the heat pump. The energetic performance is also evaluated for each system in terms of seasonal performance factor. Then, the results obtained are compared with a different system where the heat pump is equipped with an inverter and the circulation pump follows a different control logic. The size of the tank and the seasonal performance factor are therefore determined in this case too. Moreover, a “night&day” control logic is compared to these first two options to have a baseline of comparison in terms of volume of storage needed to guarantee a same level of comfort and performance. To provide information also on the running costs, a parametric analysis was run varying the type of control, the heat pump and the tank sizes for different load profiles. The results show that the size of the heat pump has a significant effect on the comfort of the user, which usually leads to oversizing of the storage tank when the load profile is unknown. With regard to this, the results obtained for the alternative

  5. Study of a Coil Heat Exchanger with an Ice Storage System

    Directory of Open Access Journals (Sweden)

    Yan Li

    2017-12-01

    Full Text Available In this study, a coil heat exchanger with an ice storage system is analyzed by theoretical analysis, numerical analysis, and experimental analysis. The dynamic characteristics of ice thickness variation is studied by means of unstable heat conduction theory in cylindrical coordinates, and the change rule of the ice layer thickness is obtained. The computational fluid dynamics method is employed to simulate the flow field and ice melting process of the coil heat exchanger. The effect of the agitator height on the flow characteristics and heat transfer characteristics is investigated. The numerical results show that the turbulence intensity of the fluid near the wall of the heat exchanger is the largest with an agitator height of 80 mm. Furthermore, the process of ice melting is analyzed. The ice on the outer side of the evaporator tube close to the container wall melts faster than the inner side and this agrees well with the experimental result. The experimental study on the process of the operational period and deicing of the coil heat exchanger is conducted and the temperature variation curves are obtained by the arrangement of thermocouples. It is found that the temperature of the evaporating tube increases with increasing height in the process of ice storage.

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

    Science.gov (United States)

    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.

  7. Experimental determination of the heat transfer and cold storage characteristics of a microencapsulated phase change material in a horizontal tank

    International Nuclear Information System (INIS)

    Allouche, Yosr; Varga, Szabolcs; Bouden, Chiheb; Oliveira, Armando C.

    2015-01-01

    Highlights: • Cold storage characteristics in latent and sensible heat storage mediums were studied. • Thermo-physical characterization of the phase change material was carried out. • A non-Newtonian shear thickening behavior of the phase change material was observed. • An energy storage enhancement (53%) was observed in the latent heat storage medium. - Abstract: In the present paper, the performance of a microencapsulated phase change material (in 45% w/w concentration) for low temperature thermal energy storage, suitable for air conditioning applications is studied. The results are compared to a sensible heat storage unit using water. Thermo-physical properties such as the specific heat, enthalpy variation, thermal conductivity and density are also experimentally determined. The non-Newtonian shear-thickening behavior of the phase change material slurry is quantified. Thermal energy performance is experimentally determined for a 100 l horizontal tank. The heat transfer between the heat transfer fluid and the phase change material was provided by a tube-bundle heat exchanger inside the tank. The results show that the amount of energy stored using the phase change material is 53% higher than for water after 10 h of charging, for the same storage tank volume. It was found that the heat transfer coefficient between the phase change material and the tube wall increases during the phase change temperature range, however it remains smaller than the values obtained for water

  8. Thermo-Hydraulic Analysis of Heat Storage Filled with the Ceramic Bricks Dedicated to the Solar Air Heating System.

    Science.gov (United States)

    Nemś, Magdalena; Nemś, Artur; Kasperski, Jacek; Pomorski, Michał

    2017-08-12

    This article presents the results of a study into a packed bed filled with ceramic bricks. The designed storage installation is supposed to become part of a heating system installed in a single-family house and eventually to be integrated with a concentrated solar collector adapted to climate conditions in Poland. The system's working medium is air. The investigated temperature ranges and air volume flow rates in the ceramic bed were dictated by the planned integration with a solar air heater. Designing a packed bed of sufficient parameters first required a mathematical model to be constructed and heat exchange to be analyzed, since heat accumulation is a complex process influenced by a number of material properties. The cases discussed in the literature are based on differing assumptions and different formulas are used in calculations. This article offers a comparison of various mathematical models and of system operating parameters obtained from these models. The primary focus is on the Nusselt number. Furthermore, in the article, the thermo-hydraulic efficiency of the investigated packed bed is presented. This part is based on a relationship used in solar air collectors with internal storage.

  9. Thermo-Hydraulic Analysis of Heat Storage Filled with the Ceramic Bricks Dedicated to the Solar Air Heating System

    Science.gov (United States)

    Nemś, Magdalena; Nemś, Artur; Kasperski, Jacek; Pomorski, Michał

    2017-01-01

    This article presents the results of a study into a packed bed filled with ceramic bricks. The designed storage installation is supposed to become part of a heating system installed in a single-family house and eventually to be integrated with a concentrated solar collector adapted to climate conditions in Poland. The system’s working medium is air. The investigated temperature ranges and air volume flow rates in the ceramic bed were dictated by the planned integration with a solar air heater. Designing a packed bed of sufficient parameters first required a mathematical model to be constructed and heat exchange to be analyzed, since heat accumulation is a complex process influenced by a number of material properties. The cases discussed in the literature are based on differing assumptions and different formulas are used in calculations. This article offers a comparison of various mathematical models and of system operating parameters obtained from these models. The primary focus is on the Nusselt number. Furthermore, in the article, the thermo-hydraulic efficiency of the investigated packed bed is presented. This part is based on a relationship used in solar air collectors with internal storage. PMID:28805703

  10. Ventilation System Type and the Resulting Classroom Temperature and Air Quality During Heating Season

    DEFF Research Database (Denmark)

    Gao, Jie; Wargocki, Pawel; Wang, Yi

    2014-01-01

    The present study investigated how different ventilation system types influence classroom temperature and air quality. Five classrooms were selected in the same school. They were ventilated by manually operable windows, manually operable windows with exhaust fan, automatically operable windows...... with and without exhaust fan and by mechanical ventilation system. Temperature, relative humidity, carbon dioxide (CO2) concentration and opening of windows were continuously monitored for one month during heating season in 2012. Classroom with manually operable windows had the highest carbon dioxide concentration...... levels so that the estimated ventilation rate was the lowest compared with the classrooms ventilated with other systems. Temperatures were slightly lower in classroom ventilated by manually operable windows with exhaust fan. Windows were opened seldom even in the classroom ventilated by manually operable...

  11. Energy and exergy analyses of medium temperature latent heat thermal storage with high porosity metal matrix

    International Nuclear Information System (INIS)

    Kumar, Ashish; Saha, Sandip K.

    2016-01-01

    Graphical abstract: I. Metal matrix is used as the thermal conductivity enhancers (TCE) in PCM-based TES. II. Time evolution second law analysis is evaluated for different porosities and pore diameters. III. Reduction in fluctuation in HTF temperature is significantly affected by the change in porosity (ε) shown in figure. IV. Maximum energy and exergy efficiencies are obtained for porosity of 0.85. V. Effect of pore diameter on first law and second law efficiencies is found to be marginal. - Abstract: Thermal energy storage system in a concentrating solar plant (CSP) reduces the gap between energy demand and supply caused by the intermittent behaviour of solar radiation. In this paper, detailed exergy and energy analyses of shell and tube type latent heat thermal storage system (LHTES) for medium temperature solar thermal power plant (∼200 °C) are performed to estimate the net useful energy during the charging and discharging period in a cycle. A commercial-grade organic phase change material (PCM) is stored inside the annular space of the shell and the heat transfer fluid (HTF) flows through the tubes. Thermal conductivity enhancer (TCE) in the form of metal matrix is embedded in PCM to augment heat transfer. A numerical model is developed to investigate the fluid flow and heat transfer characteristics using the momentum equation and the two-temperature non-equilibrium energy equation coupled with the enthalpy method to account for phase change in PCM. The effects of storage material, porosity and pore-diameter on the net useful energy that can be stored and released during a cycle, are studied. It is found that the first law efficiency of sensible heat storage system is less compared to LHTES. With the decrease in porosity, the first law and second law efficiencies of LHTES increase for both the charging and discharging period. There is no significant variation in energy and exergy efficiencies with the change in pore-diameter of the metal matrix.

  12. Surface-near geothermal energy. Ground coupled heat pumps and underground thermal energy storage; Oberflaechennahe Geothermie. Erdgekoppelte Waermepumpen und unterirdische thermische Energiespeicher

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-07-01

    Within the eleventh International User Forum at 27th/28th September, 2011 in Regensburg (Federal Republic of Germany) the following lectures were held: (1) Ecologic evaluation of heat pumps - a question of approach (Roland Koenigsdorff); (2) An actual general comment to WHG, the preparations for the new VAUwS and possible consequences on the surface-near geothermal energy (Walker-Hertkorn); (3) Field-test experiences: Ground source heat pumps in small residential buildings (Jeannette Wapler); (4) GeoT*SOL basic - Program for the evaluation and simulation of heat pump systems (Bernhard Gatzka); (5) Monitoring and modelling of geothermal heat exchanger systems (Fabian Ochs); (6) Thermal response tests for the quality assurance of geothermal heat probes (Markus Proell); (7) Process of determining an untroubled soil temperature in comparison (Andreas Koehler); (8) Borehole resistance - Is the TRT measured value also the planning value? (Roland Koenigsdorff); (9) Consideration of the heat transport in geothermal probes (Martin Konrad); (10) Process of evaluation the sealing of geothermal probes with backfilling materials (Manfred Reuss); (11) Quality assessment of geothermal probes in real standard (Mathieu Riegger); (12) Comparison of flat collectors salt water and direct evaporation, design, impacs, consequences (Bernhard Wenzel); (13) Non-covered photovoltaic thermal collectors in heat pump systems (Erik Bertram); (14) Seasonal geothermal probe-heat storage - Heat supply concepts for objects with overbalancing heating level of more than 100 kW (Volker Liebel); (15) Application of geothermal probe fields as a cold storage (Rolf Wagner); (16) Geothermal energy and waste water warmth: State of the art and new technologies for a combined utilization (Wolfram Stodtmeister); (17) Integration of a heat pump into a solar supported local heat supply in Neckarsulm (Janet Nussbicker-Lux); (18) Regenerative heating with photovoltaics and geothermal energy (Christoph Rosinski

  13. Study of the valorisation of thermal storage and of power-to-heat. Study report + Study synthesis

    International Nuclear Information System (INIS)

    Canal, Patrick; Gerbaud, Manon; Mouret, Sylvain; Chammas, Maxime; Attard, Pierre; Bucy, Jacques de; Lochmann, Hugo; Le Gars, Loic; Payen, Luc; Lesueur, Herve

    2016-11-01

    This study aimed at assessing the potential of thermal storage and of power-to-heat in France, and at identifying relevant technological sectors by 2030. In order to do so, the study aimed at quantifying the value of these sectors for applications considered as relevant, this value lying in the valorisation of heat or electric power excesses, in the power arbitration, and in investment savings. Analyses have have been performed on case studies through an assessment of storage value and of P2H (Power-to-Heat) for the collectivity, a joint optimisation of fleet sizing and management, a modelling of power system fundamentals, an analysis of the profitability of storage and P2H projects, and an assessment of the technical source and of the impact on jobs. Thus, after an overview of thermal storage and power-to-heat technologies, and a presentation of the adopted methodology (definition of case studies, case study methodology, modelling hypotheses related to production and consumption, and modelling of the power system), the authors report the study of the sizing of biomass boilers in an urban heat network (determination of the storage value for the community), the study of development of an urban heat network (storage value for the community and for the operator, technological perspective by 2030), the study of the use of power-to-heat and storage for an urban heat network (value for the community, profitability and business model, perspective by 2030), the study of unavoidable heat recovery on an industrial site (value, profitability and business model, perspective by 2030), the study of co-generation and thermal storage on an industrial site (value, impact on income), the study of domestic thermal storage and of the flexibility of the French electric power system (impact of thermal water heaters on the flexibility), and the study of the impact on employment (jobs related to the domestic market and to the development of an exporting sector). Appendices propose sheets

  14. APPLICATIONS OF THERMAL ENERGY STORAGE TO WASTE HEAT RECOVERY IN THE FOOD PROCESSING INDUSTRY, Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Lundberg, W. L.; Christenson, James A.

    1979-07-31

    A project is discussed in which the possibilities for economical waste heat recovery and utilization in the food industry were examined. Waste heat availability and applications surveys were performed at two manufacturing plants engaged in low temperature (freezing) and high temperature (cooking, sterilizing, etc.) food processing. The surveys indicate usable waste heat is available in significant quantities which could be applied to existing, on-site energy demands resulting in sizable reductions in factory fuel and energy usage. At the high temperature plant, the energy demands involve the heating of fresh water for boiler make-up, for the food processes and for the daily clean-up operation. Clean-up poses an opportunity for thermal energy storage since waste heat is produced during the one or two production shifts of each working day while the major clean-up effort does not occur until food production ends. At the frozen food facility, the clean-up water application again exists and, in addition, refrigeration waste heat could also be applied to warm the soil beneath the ground floor freezer space. Systems to recover and apply waste heat in these situations were developed conceptually and thermal/economic performance predictions were obtained. The results of those studies indicate the economics of waste heat recovery can be attractive for facilities with high energy demand levels. Small factories, however, with relatively low energy demands may find the economics marginal although, percentagewise, the fuel and energy savings are appreciable.

  15. Discharging process of a finned heat pipe–assisted thermal energy storage system with high temperature phase change material

    International Nuclear Information System (INIS)

    Tiari, Saeed; Qiu, Songgang; Mahdavi, Mahboobe

    2016-01-01

    Highlights: • The discharging process of a latent heat thermal energy storage system is studied. • The thermal energy storage system is assisted by finned heat pipes. • The influences of heat pipe spacing and fins geometrical features are studied. • Smaller heat pipe spacing enhances the solidification rate. • Better heat pipe and fin arrangements are determined. - Abstract: This paper presents the results of a numerical study conducted to investigate the discharging process of a latent heat thermal energy storage system assisted by finned heat pipes. A two-dimensional finite volume based numerical model along with enthalpy-porosity technique is employed to simulate the phase change of storage media during the discharging mode. The thermal energy storage system in this study consists of a square container, finned heat pipes, and potassium nitrate (KNO 3 ) as the phase change material. The charging process of the same thermal energy storage system was reported in an early paper by the authors. This paper reports the results of discharging process of the thermal energy storage system. The influences of heat pipe spacing, fin geometry and quantities as well as the effects of natural convection heat transfer on the thermal performance of the storage system were studied. The results indicate that the phase change material solidification process is hardly affected by the natural convection. Decreasing the heat pipe spacing results in faster discharging process and higher container base wall temperature. Increasing the fins length does not change the discharging time but yields higher base wall temperature. Using more fins also accelerates the discharging process and increases the container base wall temperature.

  16. Modelling and simulation of phase change material latent heat storages applied to a solar-powered Organic Rankine Cycle

    International Nuclear Information System (INIS)

    Manfrida, Giampaolo; Secchi, Riccardo; Stańczyk, Kamil

    2016-01-01

    Highlights: • A mathematical model of a Latent Heat Storage system was developed. • Energy and exergy analysis of the storage system were carried out. • A solar powered ORC unit coupled with the Latent Heat Storage was studied. • The dynamic performance of the overall plant was simulated with TRNSYS. - Abstract: Solar energy is one of the most promising renewable energy sources, but is intermittent by its nature. The study of efficient thermal heat storage technologies is of fundamental importance for the development of solar power systems. This work focuses on a robust mathematical model of a Latent Heat Storage (LHS) system constituted by a storage tank containing Phase Change Material spheres. The model, developed in EES environment, provides the time-dependent temperature profiles for the PCM and the heat transfer fluid flowing in the storage tank, and the energy and exergy stored as well. A case study on the application of the LHS technology is also presented. The operation of a solar power plant associated with a latent heat thermal storage and an ORC unit is simulated under dynamic (time-varying) solar radiation conditions with the software TRNSYS. The performance of the proposed plant is simulated over a one week period, and the results show that the system is able to provide power in 78.5% of the time, with weekly averaged efficiencies of 13.4% for the ORC unit, and of 3.9% for the whole plant (from solar radiation to net power delivered by the ORC expander).

  17. Monitoring results and analysis of thermal comfort conditions in experimental buildings for different heating systems and ventilation regimes during heating and cooling seasons

    Science.gov (United States)

    Gendelis, S.; Jakovičs, A.; Ratnieks, J.; Bandeniece, L.

    2017-10-01

    This paper focuses on the long-term monitoring of thermal comfort and discomfort parameters in five small test buildings equipped with different heating and cooling systems. Calculations of predicted percentage of dissatisfied people (PPD) index and discomfort factors are provided for the room in winter season running three different heating systems - electric heater, air-air heat pump and air-water heat pump, as well as for the summer cooling with split type air conditioning systems. It is shown that the type of heating/cooling system and its working regime has an important impact on thermal comfort conditions in observed room. Recommendations for the optimal operating regimes and choice of the heating system from the thermal comfort point of view are summarized.

  18. Ultra high temperature latent heat energy storage and thermophotovoltaic energy conversion

    OpenAIRE

    Datas Medina, Alejandro; Ramos Cabal, Alba; Martí Vega, Antonio; Cañizo Nadal, Carlos del; Luque López, Antonio

    2016-01-01

    A conceptual energy storage system design that utilizes ultra high temperature phase change materials is presented. In this system, the energy is stored in the form of latent heat and converted to electricity upon demand by TPV (thermophotovoltaic) cells. Silicon is considered in this study as PCM (phase change material) due to its extremely high latent heat (1800 J/g or 500 Wh/kg), melting point (1410 C), thermal conductivity (~25 W/mK), low cost (less than $2/kg or $4/kWh) and a...

  19. Cold storage condensation heat recovery system with a novel composite phase change material

    International Nuclear Information System (INIS)

    Xia, Mingzhu; Yuan, Yanping; Zhao, Xudong; Cao, Xiaoling; Tang, Zhonghua

    2016-01-01

    Highlights: • Cold storage condensation heat recovery system using PCM was proposed. • CW with a phase change temperature of nearly 80 °C was selected as the potential PCM. • The optimal mass ratio between the CW and EG was 10:1. • The thermal and physical performances of the CW/EG were investigated. • The thermal reliability was demonstrated by 1000 cycles. - Abstract: Using condensation heat from cold storage refrigeration systems to provide heat for domestic hot water preparation and industrial hot water supply promotes energy conservation. However, few studies have investigated cold storage condensation heat recovery using phase change materials (PCMs). In this study, a cold storage condensation heat recovery system that uses PCMs has been designed and analysed. According to the principle of energy cascade recycling, different operation modes could be effectively switched to recycle condensation heat. Furthermore, a novel and suitable phase change composite material is developed for cold storage condensation heat recovery, which has a relatively large latent heat, high thermal conductivity, and an appropriate phase change temperature (i.e. 80 °C). With carnauba wax (CW) as the PCM and expanded graphite (EG) as the additive, a composite was developed with an optimal mass ratio of CW:EG = 10:1. The thermal and physical properties and the interior structure of the composite were then investigated using a scanning electron microscope (SEM), thermal constants analyser (Hot Disk), differential scanning calorimeter (DSC), and Fourier transform infrared spectrometer (FT-IR). Furthermore, experiments on the melting and solidification processes and accelerated thermal cycling were also conducted. It was found that at the optimal mass ratio of 10:1, the temperatures of the CW/EG composite in the melting and solidification processes were 81.98 °C and 80.43 °C, respectively, while the corresponding latent heats were 150.9 J/g and 142.6 J/g, respectively

  20. Design of a thermochemical heat storage system for tap water heating in the built environment

    NARCIS (Netherlands)

    Gaeini, M.; de Jong, E.C.J.; Zondag, H.A.; Rindt, C.C.M.

    2014-01-01

    Replacing the use of fossil fuel by solar energy, as one of the most promising sustainable energy sources, is of high interest, because of climate change and depletion of fossil resources. However, to reach high solar fractions and to overcome the mismatch between supply and demand of solar heat,

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

    Science.gov (United States)

    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.

  2. Preparation and characterization of a novel polymeric based solid-solid phase change heat storage material

    International Nuclear Information System (INIS)

    Xi Peng; Gu Xiaohua; Cheng Bowen; Wang Yufei

    2009-01-01

    Here we reported a two-step procedure for preparing a novel polymeric based solid-solid phase change heat storage material. Firstly, a copolymer monomer containing a polyethylene glycol monomethyl ether (MPEG) phase change unit and a vinyl unit was synthesized via the modification of hydrogen group of MPEG. Secondly, by copolymerization of the copolymer monomer and phenyl ethylene, a novel polymeric based solid-solid phase change heat storage material was prepared. The composition, structure and properties of the novel polymeric based solid-solid phase change material were characterized by IR, 1 H NMR, DSC, WAXD, and POM, respectively. The results show that the novel polymeric based solid-solid phase change material possesses of excellent crystal properties and high phase change enthalpy.

  3. Development of floating cover constructions for pond heat storage; Udvikling af flydende laagkonstruktioner til damvarmelagre. Slutrapport

    Energy Technology Data Exchange (ETDEWEB)

    Duer, K. (ed.)

    2000-07-01

    The purpose of the project was to carry out a sketch project of the new cover designs for heat storage in ponds that were developed in phase II of the project. In parallel to the sketch project minor laboratory tests were carried out in order to investigate critical details of the floating cover designs. Two types of floating covers were investigated: One of plastics and two versions based on steel. (EHS)

  4. Bed geometries, fueling strategies and optimization of heat exchanger designs in metal hydride storage systems for automotive applications: A review

    DEFF Research Database (Denmark)

    Mazzucco, Andrea; Dornheim, Martin; Sloth, Michael

    2014-01-01

    This review presents recent developments for effective heat management systems to be integrated in metal hydride storage tanks, and investigates the performance improvements and limitations of each particular solution. High pressures and high temperatures metal hydrides can lead to different design...... given to metal hydride storage tanks for light duty vehicles, since this application is the most promising one for such storage materials and has been widely studied in the literature. Enhancing cooling/heating during hydrogen uptake and discharge has found to be essential to improve storage systems...

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  6. Influence of wind power, plug-in electric vehicles, and heat storages on power system investments

    International Nuclear Information System (INIS)

    Kiviluoma, Juha; Meibom, Peter

    2010-01-01

    Due to rising fuel costs, the substantial price for CO 2 emissions and decreasing wind power costs, wind power might become the least expensive source of power for an increasing number of power systems. This poses the questions of how wind power might change optimal investments in other forms of power production and what kind of means could be used to increase power system flexibility in order to incorporate the variable power production from wind power in a cost-effective manner. We have analysed possible effects using an investment model that combines heat and power production and simulates electric vehicles. The model runs in an hourly time scale in order to accommodate the impact of variable power production from wind power. Electric vehicles store electricity for later use and can thus serve to increase the flexibility of the power system. Flexibility can also be upgraded by using heat storages with heat from heat pumps, electric heat boilers and combined heat and power (CHP) plants. Results show that there is great potential for additional power system flexibility in the production and use of heat. (author)

  7. Heat exchange studies on coconut oil cells as thermal energy storage for room thermal conditioning

    Science.gov (United States)

    Sutjahja, I. M.; Putri, Widya A.; Fahmi, Z.; Wonorahardjo, S.; Kurnia, D.

    2017-07-01

    As reported by many thermal environment experts, room air conditioning might be controlled by thermal mass system. In this paper we discuss the performance of coconut oil cells as room thermal energy storage. The heat exchange mechanism of coconut oil (CO) which is one of potential organic Phase Change Material (PCM) is studied based on the results of temperature measurements in the perimeter and core parts of cells. We found that the heat exchange performance, i.e. heat absorption and heat release processes of CO cells are dominated by heat conduction in the sensible solid from the higher temperature perimeter part to the lower temperature core part and heat convection during the solid-liquid phase transition and sensible liquid phase. The capability of heat absorption as measured by the reduction of air temperature is not influenced by CO cell size. Besides that, the application of CO as the thermal mass has to be accompanied by air circulation to get the cool sensation of the room’s occupants.

  8. Development of latent heat storage systems. New storage materials and concepts for solar energy, efficient use, and spaceflight applications. Entwicklung von Latentwaermespeichern. Neue Speichermaterialien und Konzepte fuer Solarenergie, rationelle Energienutzung und Raumfahrtanwendungen

    Energy Technology Data Exchange (ETDEWEB)

    Glueck, A.; Krause, S.; Lindner, F.; Staehle, H.J.; Tamme, R. (DLR, Stuttgart (Germany). Inst. fuer Technische Thermodynamik)

    1991-11-01

    To extend the operational range of thermal energy storage systems and to provide access to new fields of applications, it is necessary to develop storage systems with higher energy densities than can be achieved with conventional materials. Advanced storage concepts such as latent heat storage and chemical storage are suitable for this. (orig.).

  9. Heat transfer enhancement in energy storage in spherical capsules filled with paraffin wax and metal beads

    International Nuclear Information System (INIS)

    Ettouney, Hisham; Alatiqi, Imad; Al-Sahali, Mohammad; Al-Hajirie, Khalida

    2006-01-01

    Energy storage is an attractive option to conserve limited energy resources, where more than 50% of the generated industrial energy is discarded in cooling water and stack gases. This study focuses on the evaluation of heat transfer enhancement in phase change energy storage units. The experiments are performed using spherical capsules filled with paraffin wax and metal beads. The experiments are conducted by inserting a single spherical capsule filled with wax and metal beads in a stream of hot/cold air. Experimental measurements include the temperature field within the spherical capsule and in the air stream. To determine the enhancement effects of the metal beads, the measured data is correlated against those for a spherical capsule filled with pure wax. Data analysis shows a reduction of 15% in the melting and solidification times upon increasing the number and diameter of the metal beads. This reduction is caused by a similar decrease in the thermal load of the sphere due to replacement of the wax by metal beads. The small size of the spherical capsule limits the enhancement effects; this is evident upon comparison of the heat transfer in a larger size, double pipe energy storage unit, where 2% of the wax volume is replaced with metal inserts, result in a three fold reduction in the melting/solidification time and a similar enhancement in the heat transfer rate

  10. Thermal energy storage for building heating and cooling applications. Quarterly progress report, April--June 1976

    Energy Technology Data Exchange (ETDEWEB)

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

    1976-11-01

    This is the first in a series of quarterly progress reports covering activities at ORNL to develop thermal energy storage (TES) technology applicable to building heating and cooling. Studies to be carried out will emphasize latent heat storage in that sensible heat storage is held to be an essentially existing technology. Development of a time-dependent analytical model of a TES system charged with a phase-change material was started. A report on TES subsystems for application to solar energy sources is nearing completion. Studies into the physical chemistry of TES materials were initiated. Preliminary data were obtained on the melt-freeze cycle behavior and viscosities of sodium thiosulfate pentahydrate and a mixture of Glauber's salt and Borax; limited melt-freeze data were obtained on two paraffin waxes. A subcontract was signed with Monsanto Research Corporation for studies on form-stable crystalline polymer pellets for TES; subcontracts are being negotiated with four other organizations (Clemson University, Dow Chemical Company, Franklin Institute, and Suntek Research Associates). Review of 10 of 13 unsolicited proposals received was completed by the end of June 1976.

  11. A basic study on Thermosyphon-type thermal storage unit (TSU) using Nanofluid as the heat transfer medium

    Science.gov (United States)

    Li, Shuang-Fei; Wang, Ping-Yang; Liu, Zhen-hua

    2017-11-01

    This study proposed a novel thermosyphon-type thermal storage unit using water-based CuO nanofluid as the phase-change heat transfer medium. Seven tubular canisters containing solid-liquid phase-change material (PCM) with peak melting temperature of 100 °C were placed vertically into the center of the TSU which is a vertical cylindrical vessel made of stainless steel. Coat formed by depositing nanoparticles during the phase-change process was adopted to increase the wettability of the heat transfer surfaces of the canisters. We investigated the phase-change heat transfer, as well as the heat-storage and heat-release properties, of the TSU through experimental and computational analysis. Our results demonstrate that this thermal storage unit construction can propose good heat transfer and heat-storage/heat-release performance. The coating of nanoparticles onto the heat transfer surfaces increases the surface wettability and improves both the evaporation and condensation heat transfer. The main thermal resistance in the TSU results from the conductive heat transfer inside of the PCM. All phase-change thermal resistance of liquid film in charging and discharging processes can be ignored in this TSU.

  12. A basic study on Thermosyphon-type thermal storage unit (TSU) using Nanofluid as the heat transfer medium

    Science.gov (United States)

    Li, Shuang-Fei; Wang, Ping-Yang; Liu, Zhen-hua

    2018-05-01

    This study proposed a novel thermosyphon-type thermal storage unit using water-based CuO nanofluid as the phase-change heat transfer medium. Seven tubular canisters containing solid-liquid phase-change material (PCM) with peak melting temperature of 100 °C were placed vertically into the center of the TSU which is a vertical cylindrical vessel made of stainless steel. Coat formed by depositing nanoparticles during the phase-change process was adopted to increase the wettability of the heat transfer surfaces of the canisters. We investigated the phase-change heat transfer, as well as the heat-storage and heat-release properties, of the TSU through experimental and computational analysis. Our results demonstrate that this thermal storage unit construction can propose good heat transfer and heat-storage/heat-release performance. The coating of nanoparticles onto the heat transfer surfaces increases the surface wettability and improves both the evaporation and condensation heat transfer. The main thermal resistance in the TSU results from the conductive heat transfer inside of the PCM. All phase-change thermal resistance of liquid film in charging and discharging processes can be ignored in this TSU.

  13. Thermochemical Characterizations of Novel Vermiculite-LiCl Composite Sorbents for Low-Temperature Heat Storage

    Directory of Open Access Journals (Sweden)

    Yannan Zhang

    2016-10-01

    Full Text Available To store low-temperature heat below 100 °C, novel composite sorbents were developed by impregnating LiCl into expanded vermiculite (EVM in this study. Five kinds of composite sorbents were prepared using different salt concentrations, and the optimal sorbent for application was selected by comparing both the sorption characteristics and energy storage density. Textural properties of composite sorbents were obtained by extreme-resolution field emission scanning electron microscopy (ER-SEM and an automatic mercury porosimeter. After excluding two composite sorbents which would possibly exhibit solution leakage in practical thermal energy storage (TES system, thermochemical characterizations were implemented through simulative sorption experiments at 30 °C and 60% RH. Analyses of thermogravimetric analysis/differential scanning calorimetry (TGA/DSC curves indicate that water uptake of EVM/LiCl composite sorbents is divided into three parts: physical adsorption of EVM, chemical adsorption of LiCl crystal, and liquid–gas absorption of LiCl solution. Energy storage potential was evaluated by theoretical calculation based on TGA/DSC curves. Overall, EVMLiCl20 was selected as the optimal composite sorbent with water uptake of 1.41 g/g, mass energy storage density of 1.21 kWh/kg, and volume energy storage density of 171.61 kWh/m3.

  14. Assessment of adsorbate density models for numerical simulations of zeolite-based heat storage applications

    International Nuclear Information System (INIS)

    Lehmann, Christoph; Beckert, Steffen; Gläser, Roger; Kolditz, Olaf; Nagel, Thomas

    2017-01-01

    Highlights: • Characteristic curves fit for binderless Zeolite 13XBFK. • Detailed comparison of adsorbate density models for Dubinin’s adsorption theory. • Predicted heat storage densities robust against choice of density model. • Use of simple linear density models sufficient. - Abstract: The study of water sorption in microporous materials is of increasing interest, particularly in the context of heat storage applications. The potential-theory of micropore volume filling pioneered by Polanyi and Dubinin is a useful tool for the description of adsorption equilibria. Based on one single characteristic curve, the system can be extensively characterised in terms of isotherms, isobars, isosteres, enthalpies etc. However, the mathematical description of the adsorbate density’s temperature dependence has a significant impact especially on the estimation of the energetically relevant adsorption enthalpies. Here, we evaluate and compare different models existing in the literature and elucidate those leading to realistic predictions of adsorption enthalpies. This is an important prerequisite for accurate simulations of heat and mass transport ranging from the laboratory scale to the reactor level of the heat store.

  15. Thermophysical Properties of Fluid Latent Heat Storage Material using Urea-Water Mixture

    Science.gov (United States)

    Hokamura, Taku; Ohkubo, Hidetoshi; Ashizawa, Kiyonori

    This study is concerned with the measurement of thermophysical properties of a urea-water mixture with the aim of adopting the mixture as a latent heat storage material for air-conditioning systems. The urea-water mixture is made of natural substances and has a good fluidity. The urea concentration in the mixture was controlled by measuring the refractive index of the mixture. Being a multi-component substance, a urea-water solution has a liquid-solid co-existent phase on a phase-diagram. Therefore, the liquidus temperature was measured to establish a relationship between the fraction of the solid-phase and temperature. Furthermore, apparent values of specific heat and coefficient of viscosity were measured in the two-phase region where the solid phase is ice. The apparent specific heat and coefficient of viscosity were measure by using an adiabatic calorimeter and a stirring torque meter respectively. The results revealed that the urea-water mixture can probably be used as a latent heat storage material of good fluidity.

  16. Nuclear heat-load limits for above-grade storage of solid transuranium wastes

    International Nuclear Information System (INIS)

    Clontz, B.G.

    1978-06-01

    Nuclear safety and heat load limits were established for above-grade storage of transuranium (TRU) wastes. Nuclear safety limits were obtained from a study by J.L. Forstner and are summarized. Heat load limits are based on temperature calculations for TRU waste drums stored in concrete containers (hats), and results are summarized. Waste already in storage is within these limits. The limiting factors for individual drum heat load limits were (1) avoidance of temperatures in excess of 190 0 F (decomposition temperature of anion resin) when anion resin is present in a concrete hat, and (2) avoidance of temperatures in excess of 450 0 F (ignition temperature of paper) at any point inside a waste drum. The limiting factor for concrete had heat load limits was avoidance of temperatures in excess of 265 0 F (melt point of high density polyethylene) at the drum liners. A temperature profile for drums and hats filled to recommended limits is shown. Equations and assumptions used were conservative

  17. Parameter effect of a phase change thermal energy storage unit with one shell and one finned tube on its energy efficiency ratio and heat storage rate

    International Nuclear Information System (INIS)

    Wang, Wei-Wei; Wang, Liang-Bi; He, Ya-Ling

    2016-01-01

    Highlights: • The parameter effect on the performance of PCTES unit using fins is reported. • The configurations of PCTES unit using fins in optimum performance are suggested. • Two parameters to indicate the effects of PCM and tube material properties are found. • The working conditions of PCTES unit using fins in optimum performance are analyzed. - Abstract: The performance of a phase change thermal energy storage (PCTES) unit using circular finned tube is affected by many parameters. Thorough studies of the parameter effect on the performance of PCTES unit are strongly required in its optimum design process. Based on a reported energy efficiency ratio and a newly defined parameter named the heat storage rate, the parameter effect on the performance of PCTES unit using circular finned tube is numerically investigated. When the fin pitch is greater than 4 times of the inner radius of the tube, the fin height and the fin thickness have little effect on the energy efficiency ratio and the heat storage rate. When the fin pitch is small, the performance of PCTES unit becomes better using large fin height and width. The energy efficiency ratio and the heat storage rate are more sensitive to the outer tube diameter. The performance of PCTES unit using circular finned tube is best when water is used as the heat transfer fluid (HTF). When the fluid flow of HTF is in a laminar state, the energy efficiency ratio and the heat storage rate are larger than that in a turbulent state.

  18. Freestanding, heat resistant microporous film for use in energy storage devices

    Science.gov (United States)

    Pekala, Richard W.; Cherukupalli, Srinivas; Waterhouse, Robert R.

    2018-02-20

    Preferred embodiments of a freestanding, heat resistant microporous polymer film (10) constructed for use in an energy storage device (70, 100) implements one or more of the following approaches to exhibit excellent high temperature mechanical and dimensional stability: incorporation into a porous polyolefin film of sufficiently high loading levels of inorganic or ceramic filler material (16) to maintain porosity (18) and achieve low thermal shrinkage; use of crosslinkable polyethylene to contribute to crosslinking the polymer matrix (14) in a highly inorganic material-filled polyolefin film; and heat treating or annealing of biaxially oriented, highly inorganic material-filled polyolefin film above the melting point temperature of the polymer matrix to reduce residual stress while maintaining high porosity. The freestanding, heat resistant microporous polymer film embodiments exhibit extremely low resistance, as evidenced by MacMullin numbers of less than 4.5.

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

    International Nuclear Information System (INIS)

    Jain, M.; Boetter-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 is a wall of a low-level radioactive-waste storage facility containing distributed sources of 60 Co and 13C s has been investigated. Dose-depth profiles 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. (author)

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

    DEFF Research Database (Denmark)

    Jain, M.; Bøtter-Jensen, L.; Murray, A.S.

    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......-137 has been investigated. Dose-depth profiles 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...... 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 Co-60 and Cs...

  1. Computational modeling of latent-heat-storage in PCM modified interior plaster

    Energy Technology Data Exchange (ETDEWEB)

    Fořt, Jan; Maděra, Jiří; Trník, Anton; Pavlíková, Milena; Pavlík, Zbyšek [Department of Materials Engineering and Chemistry, Faculty of Civil Engineering, Czech Technical University in Prague, Thákurova 7, 166 29 Prague (Czech Republic)

    2016-06-08

    The latent heat storage systems represent a promising way for decrease of buildings energy consumption with respect to the sustainable development principles of building industry. The presented paper is focused on the evaluation of the effect of PCM incorporation on thermal performance of cement-lime plasters. For basic characterization of the developed materials, matrix density, bulk density, and total open porosity are measured. Thermal conductivity is accessed by transient impulse method. DSC analysis is used for the identification of phase change temperature during the heating and cooling process. Using DSC data, the temperature dependent specific heat capacity is calculated. On the basis of the experiments performed, the supposed improvement of the energy efficiency of characteristic building envelope system where the designed plasters are likely to be used is evaluated by a computational analysis. Obtained experimental and computational results show a potential of PCM modified plasters for improvement of thermal stability of buildings and moderation of interior climate.

  2. Heat transfer from aluminum to He II: application to superconductive magnetic energy storage

    International Nuclear Information System (INIS)

    Van Sciver, S.W.; Boom, R.W.

    1979-01-01

    Heat transfer problems associated with large scale Superconductive Magnetic Energy Storage (SMES) are unique due to the proposed size of a unit. The Wisconsin design consists of a cryogenically stable magnet cooled with He II at 1.8 K. The special properties of He II (T 2 at 1.91 K and a recovery at 0.7 W/cm 2 . The advantages of operating the magnet under subcooled conditions are exemplified by improved heat transfer. The maximum at 1.89 K and 1.3 atm pressure is 2.3 W/cm 2 with recovery enhanced to 1.9 W/cm 2 . A conservative maximum heat flux of 0.5 W/cm 2 with an associated temperature difference of 0.5 K has been chosen for design. Elements of the experimental study as well as the design will be discussed

  3. Numerical study of finned heat pipe-assisted thermal energy storage system with high temperature phase change material

    International Nuclear Information System (INIS)

    Tiari, Saeed; Qiu, Songgang; Mahdavi, Mahboobe

    2015-01-01

    Highlights: • A finned heat pipe-assisted latent heat thermal energy storage system is studied. • The effects of heat pipes spacing and fins geometrical features are investigated. • Smaller heat pipes spacing and longer fins improve the melting rate. • The optimal heat pipe and fin arrangements are determined. - Abstract: In the present study, the thermal characteristics of a finned heat pipe-assisted latent heat thermal energy storage system are investigated numerically. A transient two-dimensional finite volume based model employing enthalpy-porosity technique is implemented to analyze the performance of a thermal energy storage unit with square container and high melting temperature phase change material. The effects of heat pipe spacing, fin length and numbers and the influence of natural convection on the thermal response of the thermal energy storage unit have been studied. The obtained results reveal that the natural convection has considerable effect on the melting process of the phase change material. Increasing the number of heat pipes (decreasing the heat pipe spacing) leads to the increase of melting rate and the decrease of base wall temperature. Also, the increase of fin length results in the decrease of temperature difference within the phase change material in the container, providing more uniform temperature distribution. It was also shown that number of the fins does not have a significant effect on the performance of the system

  4. Integration and Validation of a Thermal Energy Storage System for Electric Vehicle Cabin Heating

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Mingyu [MAHLE Behr Troy Inc.; Craig, Timothy [MAHLE Behr Troy Inc.; Wolfe, Edward [MAHLE Behr Troy Inc.; LaClair, Tim J. [ORNL; Gao, Zhiming [ORNL; Levin, Michael [Ford Motor Company; Demitroff, Danrich [Ford Motor Company; Shaikh, Furqan [Ford Motor Company

    2017-03-01

    It is widely recognized in the automotive industry that, in very cold climatic conditions, the driving range of an Electric Vehicle (EV) can be reduced by 50% or more. In an effort to minimize the EV range penalty, a novel thermal energy storage system has been designed to provide cabin heating in EVs and Plug-in Hybrid Electric Vehicles (PHEVs) by using an advanced phase change material (PCM). This system is known as the Electrical PCM-based Thermal Heating System (ePATHS) [1, 2]. When the EV is connected to the electric grid to charge its traction battery, the ePATHS system is also “charged” with thermal energy. The stored heat is subsequently deployed for cabin comfort heating during driving, for example during commuting to and from work.The ePATHS system, especially the PCM heat exchanger component, has gone through substantial redesign in order to meet functionality and commercialization requirements. The final system development for EV implementation has occurred on a mid-range EV and has been evaluated for its capability to extend the driving range. Both simulated driving in a climatic tunnel and actual road testing have been carried out. The ePATHS has demonstrated its ability to supply the entire cabin heating needs for a round trip commute totaling 46 minutes, including 8 hours of parking, at an ambient temperature of -10°C.

  5. Seasonal Variations of the Surface Urban Heat Island in a Semi-Arid City

    Directory of Open Access Journals (Sweden)

    Sirous Haashemi

    2016-04-01

    Full Text Available The process of the surface urban heat island (SUHI varies with latitude, climate, topography and meteorological conditions. This study investigated the seasonal variability of SUHI in the Tehran metropolitan area, Iran, with respect to selected surface biophysical variables. Terra Moderate Resolution Imaging Spectroradiometer (MODIS Land Surface Temperature (LST was retrieved as nighttime LST data, while daytime LST was retrieved from Landsat 8 Thermal Infrared Sensor (TIRS using the split-window algorithm. Both data covered the time period from September 2013 to September 2015. To assess SUHI intensity, we employed three SUHI indicators, i.e., the LST difference of urban-rural, that of urban-agriculture and that of urban-water. Physical and biophysical surface variables, including land use and land cover (LULC, elevation, impervious surface (IS, fractional vegetation cover (FVC and albedo, were selected to estimate the relationship between LST seasonal variability and the surface properties. Results show that an inversion of the SUHI phenomenon (i.e., surface urban cool island existed at daytime with the maximal value of urban-rural LST difference of −4 K in March; whereas the maximal value of SUHI at nighttime yielded 3.9 K in May. When using the indicators of urban-agriculture and urban-water LST differences, the maximal value of SUHI was found to be 8.2 K and 15.5 K, respectively. Both results were observed at daytime, suggesting the role of bare soils in the inversion of the SUHI phenomenon with the urban-rural indicator. Maximal correlation was observed in the relationship between night LST and elevation in spring (coefficient: −0.76, night LST and IS in spring (0.60, night LST and albedo in winter (−0.53 and day LST with fractional vegetation cover in summer (−0.41. The relationship between all surface properties with LST possessed large seasonal variations, and thus, using these relationships for SUHI modeling may not be

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

    NARCIS (Netherlands)

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

    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

  7. Solar cooker of the portable parabolic type incorporating heat storage based on PCM

    International Nuclear Information System (INIS)

    Lecuona, Antonio; Nogueira, José-Ignacio; Ventas, Rubén; Rodríguez-Hidalgo, María-del-Carmen; Legrand, Mathieu

    2013-01-01

    Highlights: ► A portable utensil for commercial paraboloid type solar cookers is proposed. ► It includes heat storage with phase change materials (PCMs). ► The utensil is stored indoors in a thermally insulating box after charging. ► A thermal 1-D model predicts its performance in sunny days. ► The set allows cooking lunch, dinner and next day the breakfast for a family. - Abstract: This paper reviews relevant issues on solar cooking in order to define and evaluate an innovative layout of a portable solar cooker of the standard concentrating parabolic type that incorporates a daily thermal storage utensil. This utensil is formed by two conventional coaxial cylindrical cooking pots, an internal one and a larger external one. The void space between the two coaxial pots is filled with a phase change material (PCM) forming an intermediate jacket. The ensemble is thermally simulated using 1-D finite differences. A lumped elements model with convective heat transfer correlations is used for the internal behavior of the utensil, subjected to external radiation. This numerical model is used to study its transient behavior for the climatic conditions of Madrid, and validated with experimental data. Two options have been checked as possible PCMs: technical grade paraffin and erythritol. The results indicate that cooking the lunch for a family is possible simultaneously with heat storage along the day. Keeping afterwards the utensil inside an insulating box indoors allows cooking the dinner with the retained heat and also the next day breakfast. This expands the applicability of solar cooking and sustains the possibility of all the day around cooking using solar energy with a low inventory cost

  8. Minimizing temperature instability of heat recovery hot water system utilizing optimized thermal energy storage

    Science.gov (United States)

    Suamir, I. N.; Sukadana, I. B. P.; Arsana, M. E.

    2018-01-01

    One energy-saving technology that starts gaining attractive for hotel industry application in Indonesia is the utilization of waste heat of a central air conditioning system to heat water for domestic hot water supply system. Implementing the technology for such application at a hotel was found that hot water capacity generated from the heat recovery system could satisfy domestic hot water demand of the hotel. The gas boilers installed in order to back up the system have never been used. The hot water supply, however, was found to be instable with hot water supply temperature fluctuated ranging from 45 °C to 62 °C. The temperature fluctuations reaches 17 °C, which is considered instable and can reduce hot water usage comfort level. This research is aimed to optimize the thermal energy storage in order to minimize the temperature instability of heat recovery hot water supply system. The research is a case study approach based on cooling and hot water demands of a hotel in Jakarta-Indonesia that has applied water cooled chillers with heat recovery systems. The hotel operation with 329 guest rooms and 8 function rooms showed that hot water production in the heat recovery system completed with 5 m3 thermal energy storage (TES) could not hold the hot water supply temperature constantly. The variations of the cooling demand and hot water demands day by day were identified. It was found that there was significant mismatched of available time (hours) between cooling demand which is directly correlated to the hot water production from the heat recovery system and hot water usage. The available TES system could not store heat rejected from the condenser of the chiller during cooling demand peak time between 14.00 and 18.00 hours. The extra heat from the heat recovery system consequently increases the temperature of hot water up to 62 °C. It is about 12 K above 50 °C the requirement hot water temperature of the hotel. In contrast, the TES could not deliver proper

  9. Seasonal and Spatial Characteristics of Urban Heat Islands (UHIs in Northern West Siberian Cities

    Directory of Open Access Journals (Sweden)

    Victoria Miles

    2017-09-01

    Full Text Available Anthropogenic heat and modified landscapes raise air and surface temperatures in urbanized areas around the globe. This phenomenon is widely known as an urban heat island (UHI. Previous UHI studies, and specifically those based on remote sensing data, have not included cities north of 60°N. A few in situ studies have indicated that even relatively small cities in high latitudes may exhibit significantly amplified UHIs. The UHI characteristics and factors controlling its intensity in high latitudes remain largely unknown. This study attempts to close this knowledge gap for 28 cities in northern West Siberia (NWS. NWS cities are convenient for urban intercomparison studies as they have relatively similar cold continental climates, and flat, rather homogeneous landscapes. We investigated the UHI in NWS cities using the moderate-resolution imaging spectroradiometer (MODIS MOD 11A2 land surface temperature (LST product in 8-day composites. The analysis reveals that all 28 NWS cities exhibit a persistent UHI in summer and winter. The LST analysis found differences in summer and winter regarding the UHI effect, and supports the hypothesis of seasonal differences in the causes of UHI formation. Correlation analysis found the strongest relationships between the UHI and population (log P. Regression models using log P alone could explain 65–67% of the variability of UHIs in the region. Additional explanatory power—at least in summer—is provided by the surrounding background temperatures, which themselves are strongly correlated with latitude. The performed regression analysis thus confirms the important role of the surrounding temperature in explaining spatial–temporal variation of UHI intensity. These findings suggest a climatological basis for these phenomena and, given the importance of climatic warming, an aspect that deserves future study.

  10. Advice on Sustainable Use of the Underground for Heat and Cold Storage; Advies Duurzaam Gebruik van de Bodem voor WKO

    Energy Technology Data Exchange (ETDEWEB)

    Oomes, J.

    2009-09-15

    Insights and ideas are given and discussed with regard to sustainable use of soil and underground for heat and cold storage. Also attention is paid to the marginal conditions for the application of heat and cold storage [Dutch] Inzichten en ideeen worden gegeven en besproken over duurzaam gebruik van de bodem voor warmte- koudeopslag (WKO). Daarnaast worden ook de randvoorwaarden van WKO in kaart gebracht.

  11. Use of salt hydrates as a heat storage medium for loading latent heat stores

    Energy Technology Data Exchange (ETDEWEB)

    Wasel-Nielen, J.; Merkenich, K.; Gehrig, O.; Sommer, K.

    1985-05-15

    The use of salt hydrate melting in the loading process is not favourable from the technical and energy point of view. According to the invention, a saturated solution is filled into the store at the required phase conversion point. This can be done by neutralization (e.g. a reaction between H/sub 3/PO4/NaOH/H/sub 2/O in the mol ratio of 1/2/10 gives Na/sub 2/HPO/sub 4/.12H/sub 2/O corresponding to Na/sub 2/SO/sub 4/.10H/sub 2/O), or by conversion of acid/basic salts with bases/acids respectively (e.g.Na/sub 3/PO/sub 4//H/sub 3/PO/sub 4//H/sub 2/O in the ratio 2/1/36 to Na/sub 2/HPO/sub 4/.12H/sub 2/O, analogous to K/sub 3/PO/sub 4/.7H/sub 2/O, KF.4H/sub 2/O or CaCl/sub 2/.6H/sub 2/O). During the process one must ensure accurate dosing and good mixing. A saturated solution is also available by dissolving salts free of water/or with little water in appropriate quantities of water below the melting point of the required hydrate. Such systems are used where the phase change heat exceeds the heat capacity of the water at this temperature and the hydrates should contain at least three crystal water molecules more than the nearest hydrate.

  12. Current status of and problems in ice heat storage systems contributing to improving load rate. Air conditioning system utilizing ice heat storage and building frame storage (Takenaka Corporation); Fukaritsu kaizen ni kokensuru kori chikunetsu system no genjo to kadai. Kori chikunetsu to kutai chikunetsu wo riyoshita kucho system

    Energy Technology Data Exchange (ETDEWEB)

    Inoue, Y.; Yoshitake, Y. [Takenaka Corp., Osaka (Japan)

    1998-02-01

    Development was made on a new air conditioning system, `building frame heat storage air conditioning system`, which combines an ice heat storage system with a building frame heat storage. With the building frame heat storage system, a damper is installed on an indoor device to blow cold air from the air conditioner onto slabs on the upper floor during nighttime power generating period. Heat is stored in beams, pillars and walls, and the shell absorbs and dissipates heat during daytime. Since general office buildings consume primary energy at 22.8% for heat source and 26.9% for transportation, which is greater, a natural coolant circulation type air conditioning system was developed as an air conditioning system for the secondary side. This made the building frame heat regeneration possible for the first time. With regard to heat storage quantity and heat dissipation quantity, the quantity of heat which can be stored during nighttime (10 hours) and dissipated during air conditioning using period in daytime (10 hours) is 80% of the stored heat quantity. This system was installed in a building in Kobe City. As a result of the measurement, it was found that indoor heat load reduction rate as a result of using the building frame heat storage was 24% or more in summer and 80% or more in winter. 7 figs., 2 tabs.

  13. Energy Performance and Economic Evaluation of Heat Pump/Organic Rankine Cycle System with Sensible Thermal Storage

    DEFF Research Database (Denmark)

    Carmo, C.; Dumont, O.; Nielsen, M. P.

    2016-01-01

    that consists of a ground-source heat pump with possibility of reversing operation as an ORC power cycle combined with solar heating in a single-family building is introduced. The ORC mode enables the use of solar energy in periods of no heat energy demand and reverses the heat pump cycle to supply electrical...... power.This paper combines a dynamic model based on empirical data of the HP/ORC system with lessons learned from 140 heat pump installations operating in real-life conditions in a cold climate. These installations were monitored for a period up to 5 years.Based on the aforementioned model and real......-life conditions knowledge, the paper considers two different sensible energy storage (TES) configurations for the reversible heat pump/organic Rankine cycle (HP/ORC) system: a buffer tank for both space heating and domestic hot water and a hot water storage tank used exclusively for domestic hot water...

  14. Thermal energy storage in the form of heat or cold with using of the PCM-based accumulation panels

    Directory of Open Access Journals (Sweden)

    Skovajsa Jan

    2016-01-01

    Full Text Available This article describes the usage of thermal energy storage in the form of heat and cold with an adaptation of the special device which is composed of the thermal panels. These panels are based on the phase change materials (PCM for normal inner environment temperature in buildings. The energy for the thermal energy storage is possible to get from built-in electric heating foil or from the tube heat exchanger, which is build in the thermal panels. This technology is able to use renewable energy sources, for example, solar thermal collectors and air-to-water heat pump as a source of heat for heating of the hot water tank. In the cooling mode, there is able to use the heat pump or photovoltaics panels in combination with thermoelectric coolers for cooling.

  15. Design and Testing of a Thermal Storage System for Electric Vehicle Cabin Heating

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Mingyu [MAHLE Behr Troy Inc.; WolfeIV, Edward [MAHLE Behr Troy Inc.; Craig, Timothy [MAHLE Behr Troy Inc.; LaClair, Tim J [ORNL; Gao, Zhiming [ORNL; Abdelaziz, Omar [ORNL

    2016-01-01

    Without the waste heat available from the engine of a conventional automobile, electric vehicles (EVs) must provide heat to the cabin for climate control using energy stored in the vehicle. In current EV designs, this energy is typically provided by the traction battery. In very cold climatic conditions, the power required to heat the EV cabin can be of a similar magnitude to that required for propulsion of the vehicle. As a result, the driving range of an EV can be reduced very significantly during winter months, which limits consumer acceptance of EVs and results in increased battery costs to achieve a minimum range while ensuring comfort to the EV driver. To minimize the range penalty associated with EV cabin heating, a novel climate control system that includes thermal energy storage has been designed for use in EVs and plug-in hybrid electric vehicles (PHEVs). The system uses the stored latent heat of an advanced phase change material (PCM) to provide cabin heating. The PCM is melted while the EV is connected to the electric grid for charging of the electric battery, and the stored energy is subsequently transferred to the cabin during driving. To minimize thermal losses when the EV is parked for extended periods, the PCM is encased in a high performance insulation system. The electrical PCM-Assisted Thermal Heating System (ePATHS) was designed to provide enough thermal energy to heat the EV s cabin for approximately 46 minutes, covering the entire daily commute of a typical driver in the U.S.

  16. Seasonal and spatial dynamics of gas ebullition in a temperate water-storage reservoir

    Czech Academy of Sciences Publication Activity Database

    Tušer, Michal; Picek, T.; Sajdlová, Zuzana; Jůza, Tomáš; Muška, Milan; Frouzová, Jaroslava

    2017-01-01

    Roč. 53, č. 10 (2017), s. 8266-8276 ISSN 0043-1397 R&D Projects: GA ČR GAP504/12/1186; GA MŠk(CZ) LM2015075; GA MŠk(CZ) EF16_013/0001782 Institutional support: RVO:60077344 Keywords : ebullitive flux * hydroacoustics * methane * river impoundment * season Subject RIV: DA - Hydrology ; Limnology OBOR OECD: Marine biology, freshwater biology, limnology Impact factor: 4.397, year: 2016

  17. A Preliminary Study on Rock Bed Heat Storage from Biomass Combustion for Rice Drying

    Science.gov (United States)

    Nelwan, L. O.; Wulandani, D.; Subrata, I. D. M.

    2018-05-01

    One of the main constraints of biomass fuel utilization in a small scale rice drying system is the operating difficulties related to the adjustment of combustion/feeding rate. Use of thermal storage may reduce the problem since combustion operation can be accomplished in a much shorter time and then the use of heat can be regulated by simply adjusting the air flow. An integrated biomass furnace-rock bed thermal storage with a storage volume of 540 L was designed and tested. There were four experiments conducted in this study. Charging was performed within 1-2 hours with a combustion rate of 11.5-15.5 kg/h. In discharging process, the mixing of air passing through the rock bed and ambient air were regulated by valves. Without adjusting the valve during the discharging process, air temperature increased up to 80°C, which is not suitable for rice batch drying process. Charging with sufficiently high combustion rate (14 kg/h) within 1 hour continued by adjusting the valve during discharging process below 60°C increased the discharge-charge time ratio (DCTR) up to 5.33 at average air temperature of 49°C and ambient temperature of 33°C.The efficiency of heat discharging was ranged from 34.5 to 45.8%. From the simulation, as much as 156.8-268.8 kg of rice was able to be dried by the discharging conditions.

  18. Heat storage in Asian elephants during submaximal exercise: behavioral regulation of thermoregulatory constraints on activity in endothermic gigantotherms.

    Science.gov (United States)

    Rowe, M F; Bakken, G S; Ratliff, J J; Langman, V A

    2013-05-15

    Gigantic size presents both opportunities and challenges in thermoregulation. Allometric scaling relationships suggest that gigantic animals have difficulty dissipating metabolic heat. Large body size permits the maintenance of fairly constant core body temperatures in ectothermic animals by means of gigantothermy. Conversely, gigantothermy combined with endothermic metabolic rate and activity likely results in heat production rates that exceed heat loss rates. In tropical environments, it has been suggested that a substantial rate of heat storage might result in a potentially lethal rise in core body temperature in both elephants and endothermic dinosaurs. However, the behavioral choice of nocturnal activity might reduce heat storage. We sought to test the hypothesis that there is a functionally significant relationship between heat storage and locomotion in Asian elephants (Elephas maximus), and model the thermoregulatory constraints on activity in elephants and a similarly sized migratory dinosaur, Edmontosaurus. Pre- and post-exercise (N=37 trials) measurements of core body temperature and skin temperature, using thermography were made in two adult female Asian elephants at the Audubon Zoo in New Orleans, LA, USA. Over ambient air temperatures ranging from 8 to 34.5°C, when elephants exercised in full sun, ~56 to 100% of active metabolic heat production was stored in core body tissues. We estimate that during nocturnal activity, in the absence of solar radiation, between 5 and 64% of metabolic heat production would be stored in core tissues. Potentially lethal rates of heat storage in active elephants and Edmontosaurus could be behaviorally regulated by nocturnal activity.

  19. Constraining Parameter Uncertainty in Simulations of Water and Heat Dynamics in Seasonally Frozen Soil Using Limited Observed Data

    Directory of Open Access Journals (Sweden)

    Mousong Wu

    2016-02-01

    Full Text Available Water and energy processes in frozen soils are important for better understanding hydrologic processes and water resources management in cold regions. To investigate the water and energy balance in seasonally frozen soils, CoupModel combined with the generalized likelihood uncertainty estimation (GLUE method was used. Simulation work on water and heat processes in frozen soil in northern China during the 2012/2013 winter was conducted. Ensemble simulations through the Monte Carlo sampling method were generated for uncertainty analysis. Behavioral simulations were selected based on combinations of multiple model performance index criteria with respect to simulated soil water and temperature at four depths (5 cm, 15 cm, 25 cm, and 35 cm. Posterior distributions for parameters related to soil hydraulic, radiation processes, and heat transport indicated that uncertainties in both input and model structures could influence model performance in modeling water and heat processes in seasonally frozen soils. Seasonal courses in water and energy partitioning were obvious during the winter. Within the day-cycle, soil evaporation/condensation and energy distributions were well captured and clarified as an important phenomenon in the dynamics of the energy balance system. The combination of the CoupModel simulations with the uncertainty-based calibration method provides a way of understanding the seasonal courses of hydrology and energy processes in cold regions with limited data. Additional measurements may be used to further reduce the uncertainty of regulating factors during the different stages of freezing–thawing.

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

    Science.gov (United States)

    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.

  1. Heat storage in underground caverns - measurements and simulations; Speicherung von Waerme in Grubenraeumen - Messung und Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Schaberg, A; Krause, H; Poetke, W [TU Bergakademie Freiberg (Germany). Inst. fuer Waermetechnik und Technische Thermodynamik

    1997-12-01

    Among the different discussed underground concepts for longterm storing of solar or waste heat old waterfilled mines can be an interesting solution. To examine the temperature behaviour of this storage type a testing store is built in a mine belonging to the Freiberg University of Mining and Technology in Saxonia. In a longterm project temperatures are measured inside the water volume and in the adjacent rock. The temperature behaviour depends on the operating conditions. Inside the water volume temperature stratification can be observed. During loading and standstill heat is transported into the rock surrounding. A certain part of this amount of heat can be discharged again. For designing and optimizing this storage type a numerical modell is developed. The modell is validated with experimental data from the testing plant. (orig.) [Deutsch] Unter den verschiedenen, in der Diskussion stehenden Untegrund-Waermespeichern fuer Solarwaerme oder Abwaerme bieten sich auch geflutete Gruben als Waermespeicher an. Zur Untersuchung des Temperaturverhaltens dieses Speichertyps ist im Saechsischen Lehr- und Besucherbergwerk der TU Bergakademie Freiberg ein Versuchsspeicher errichtet worden. In einem Langzeitversuch wird das Temperaturfeld im Wasser und im angrenzenden Gestein aufgezeichnet. Das Temperaturverhalten ist von den Betriebsgroessen abhaengig. Im Grubenwasser stellt sich eine stabile Temperaturschichtung ein. Waehrend der Beladung und der Stillstandszeiten wird Waerme in die Gesteinsumgebung transportiert. Ein Teil dieser Waermemenge kann wider entspeichert werden. Zur Auslegung und Optimierung von Gruben-Waermespeichern ist ein numerisches Modell entwickelt worden. Das Modell ist anhand der Messergebnisse des Versuchsspeichers validiert worden. (orig.)

  2. Ecosystem carbon storage and partitioning in a tropical seasonal forest in Southwestern China

    DEFF Research Database (Denmark)

    Lü, Xiao-Tao; Yin, Jiang-Xia; Jepsen, Martin Rudbeck

    2010-01-01

    in Malaysia. The variation of C storage in the tree layer among different plots was mainly due to different densities of large trees (DBH > 70 cm). The contributions of the shrub layer, herb layer, woody lianas, and fine litter each accounted for 1-2 t C ha-1 to the total carbon stock. The mineral soil C...... for conservation planning....

  3. FY 17 Q1 Commercial integrated heat pump with thermal storage milestone report

    Energy Technology Data Exchange (ETDEWEB)

    Abu-Heiba, Ahmad [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Baxter, Van D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shen, Bo [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Rice, C. Keith [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-01-01

    The commercial integrated heat pump with thermal storage (AS-IHP) offers significant energy saving over a baseline heat pump with electric water heater. The saving potential is maximized when the AS-IHP serves coincident high water heating and high space cooling demands. A previous energy performance analysis showed that the AS-IHP provides the highest benefit in the hot-humid and hot-dry/mixed dry climate regions. Analysis of technical potential energy savings for these climate zones based on the BTO Market calculator indicated that the following commercial building market segments had the highest water heating loads relative to space cooling and heating loads education, food service, health care, lodging, and mercantile/service. In this study, we focused on these building types to conservatively estimate the market potential of the AS-IHP. Our analysis estimates maximum annual shipments of ~522,000 units assuming 100% of the total market is captured. An early replacement market based on replacement of systems in target buildings between 15 and 35 years old was estimated at ~136,000 units. Technical potential energy savings are estimated at ~0.27 quad based on the maximum market estimate, equivalent to ~13.9 MM Ton CO2 emissions reduction.

  4. Identification and changes in the seasonal concentrations of heat shock proteins in roe deer (Capreolus capreolus) epididymides.

    Science.gov (United States)

    Majewska, A M; Kordan, W; Koziorowska-Gilun, M; Wysocki, P

    2017-02-01

    Heat shock proteins (HSPs) act as molecular chaperones with important regulatory functions. HSPs are considered to be essential factors in animal reproduction. In view of seasonal variations in the secretory activity of the reproductive tract of mature roe deer (Capreolus capreolus), the aims of this study were to identify HSPs in the epididymides and compare the expression of the identified proteins in three periods of the reproductive season. Two-dimensional polyacrylamide gel electrophoresis revealed the highest number of polypeptides in homogenates of epididymal tissues and in caput, corpus and cauda epididymal fluids throughout the reproductive season. Epididymal tissue homogenates and epididymal fluids were analysed by tandem mass spectrometry (MS/MS) to reveal 31 polypeptides with enzymatic activity, including polypeptides with antioxidant properties, structural and cell signalling functions. Moreover, among the identified polypeptides, five of them were similar to heat shock proteins: endoplasmin (Grp94); heat shock protein 90 kDa (HSP90); 78-kDa glucose-regulated protein (Grp78); chain A, the crystal structure of the human HSP70 ATPase domain and heat shock protein beta-1 isoform X. The concentrations of the analysed polypeptides, expressed in optical density units (ODU), differed significantly (p ≤ .05) across the examined periods of the reproductive season. The highest ODU values for almost all analysed proteins were observed during the rutting period. The presence of HSPs in the epididymal tissues and fluids of roe deer in different periods of the reproductive season could indicate that those proteins play an important role in sperm maturation in the epididymis. © 2016 Blackwell Verlag GmbH.

  5. Seasonal coefficient of performance for ground source heat pump and groundwater one in Białystok

    Science.gov (United States)

    Gajewski, Andrzej

    2017-11-01

    European Economic Area (EEA) states declare to contain greenhouse gases emissions at 20% by 2020, whereas European Union (EU) does 40% before 2030, which result in encouragement to apply low-carbon technologies. Coefficient of Performance (COP) and Seasonal Coefficient of Performance (SCOPnet) are obtained using temperature measurement done by The Institute of Meteorology and Water Management - National Research Institute (IMGW-PIB) at the weather station in Bialystok for ten-year period. The first variant is ground source heat pump (GSHP) and the second one is groundwater source heat pump (WSHP) which can be equipped with separating heat exchanger (SHE) optionally. In both cases heat is generated for heating system only. Ground temperature is determined from Baggs (1983) formula using Oleśkowicz-Popiel et. al. (2002) adaptation to Polish climate and substituting the local constants achieved by Biernacka (2010). Water temperature in a groundwater basin is obtained from Kowalski (2007) equation. Estimation is done in each hour of heating season. All COP values are higher than 3.5 required by EU (2013). SCOPnet are as follows: 6.12, 5.86, 5.03 for WSHP, WSHP+SHE, GSHP respectively. Insomuch as WSHP needs only two boreholes it is recommended to the areas beneath ones a groundwater basin is located.

  6. Seasonal coefficient of performance for ground source heat pump and groundwater one in Białystok

    Directory of Open Access Journals (Sweden)

    Gajewski Andrzej

    2017-01-01

    Full Text Available European Economic Area (EEA states declare to contain greenhouse gases emissions at 20% by 2020, whereas European Union (EU does 40% before 2030, which result in encouragement to apply low-carbon technologies. Coefficient of Performance (COP and Seasonal Coefficient of Performance (SCOPnet are obtained using temperature measurement done by The Institute of Meteorology and Water Management – National Research Institute (IMGW-PIB at the weather station in Bialystok for ten-year period. The first variant is ground source heat pump (GSHP and the second one is groundwater source heat pump (WSHP which can be equipped with separating heat exchanger (SHE optionally. In both cases heat is generated for heating system only. Ground temperature is determined from Baggs (1983 formula using Oleśkowicz-Popiel et. al. (2002 adaptation to Polish climate and substituting the local constants achieved by Biernacka (2010. Water temperature in a groundwater basin is obtained from Kowalski (2007 equation. Estimation is done in each hour of heating season. All COP values are higher than 3.5 required by EU (2013. SCOPnet are as follows: 6.12, 5.86, 5.03 for WSHP, WSHP+SHE, GSHP respectively. Insomuch as WSHP needs only two boreholes it is recommended to the areas beneath ones a groundwater basin is located.

  7. Full Scale Investigation of the Dynamic Heat Storage of Concrete Decks with PCM and Enhanced Heat Transfer Surface Area

    DEFF Research Database (Denmark)

    Pomianowski, Michal Zbigniew; Heiselberg, Per; Jensen, Rasmus Lund

    2013-01-01

    The paper presents the full-scale experimental investigation of the dynamic heat storage potential of the prefabricated hollow core deck elements with and without phase change material (PCM) and with and without increased bottom surface area of the decks. In the presented investigation five types...... of hollow core decks with different surfaces on the bottom are investigated: reference deck made of standard concrete and flat surface, deck with special mortar grooved tiles, deck with flat mortar tiles, deck with grooved mortar and phase change material tiles, deck with flat mortar and phase change...... material tiles. The experimental investigation presented in the paper is performed in the specially designed modified hot box apparatus that allows maintaining periodic steady-state tests with the full-scale concrete deck elements. The presented research investigates if the extended surface area and PCM...

  8. BWR spent fuel storage cask performance test. Volume 1. Cask handling experience and decay heat, heat transfer, and shielding data

    International Nuclear Information System (INIS)

    McKinnon, M.A.; Doman, J.W.; Tanner, J.E.; Guenther, R.J.; Creer, J.M.; King, C.E.

    1986-02-01

    This report documents a heat transfer and shielding performance test conducted on a Ridihalgh, Eggers and Associates REA 2023 boiling water reactor (BWR) spent fuel storage cask. The testing effort consisted of three parts: pretest preparations, performance testing, and post-test activities. Pretest preparations included conducting cask handling dry runs and characterizing BWR spent fuel assemblies from Nebraska Public Power District's Cooper Nuclear Station. The performance test matrix included 14 runs consisting of two loadings, two cask orientations, and three backfill environments. Post-test activities included calorimetry and axial radiation scans of selected fuel assemblies, in-basin sipping of each assembly, crud collection, video and photographic scans, and decontamination of the cask interior and exterior

  9. Energy storage using phase-change materials for active solar heating and cooling: An evaluation of future research and development direction

    Science.gov (United States)

    Borkowski, R. J.; Stovall, T. K.; Kedl, R. J.; Tomlinson, J. J.

    1982-04-01

    The current state of the art and commercial potential of active solar heating and cooling systems for buildings, and the use of thermal energy storage with these systems are assessed. The need for advanced latent heat storage subsystems in these applications and priorities for their development are determined. Latent storage subsystems are advantageous in applications where their compactness may be exploited. It is suggested that subsystems could facilitate storage in retrofit applications in which storage would be physically impossible otherwise.

  10. Experimental investigation on AC unit integrated with sensible heat storage (SHS)

    Science.gov (United States)

    Aziz, N. A.; Amin, N. A. M.; Majid, M. S. A.; Hussin, A.; Zhubir, S.

    2017-10-01

    The growth in population and economy has increases the energy demand and raises the concerns over the sustainable energy source. Towards the sustainable development, energy efficiency in buildings has become a prime objective. In this paper, the integration of thermal energy storage was studied. This paper presents an experimental investigation on the performance of an air conditioning unit integrated with sensible heat storage (SHS) system. The results were compared to the conventional AC systems in the terms of average electricity usage, indoor temperature and the relative humidity inside the experimented room (cabin container). Results show that the integration of water tank as an SHS reduces the electricity usage by 5%, while the integration of well-insulated water tank saves up to 8% of the electricity consumption.

  11. CFD Simulation of Heat and Fluid Flow for Spent Fuel in a Dry Storage

    International Nuclear Information System (INIS)

    In, Wangkee; Kwack, Youngkyun; Kook, Donghak; Koo, Yanghyun

    2014-01-01</