WorldWideScience

Sample records for building-integrated heat storage

  1. 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...

  2. Simulation of temperature in office with building integrated heating and cooling system

    DEFF Research Database (Denmark)

    Weitzmann, Peter

    2002-01-01

    by raising the temperature of the concrete to slightly above the desired room temperature. Another way of solving the problem of cooling is by using building integrated cooling in floors. This technique utilizes the thermal mass of concrete in the floors, by integrating PEX pipes in the floor. By maintaining...... and thermal comfort parameters. The model is based on a numerical Finite Control Volume (FCV) method for the heat transfer in walls, ceiling, windows and floor. The model uses both convective and radiative heat transfer to the room air and between the room surfaces. The simulation model can be used...... for calculating situations with both cooling and heating demands. Using the model it is therefore possible to assess the thermal environment, and furthermore to calculate the energy consumption required for both heating and cooling. In the paper different construction types of the floor are examined, as well...

  3. Modelling the heat dynamics of building integrated and ventilated photovoltaic modules

    DEFF Research Database (Denmark)

    Friling, N.; Jimenez, M.J.; Bloem, H.

    2009-01-01

    -up. To identify best set-up, grey-box models consisting of stochastic differential equations are applied. The models are first order stochastic state space models. Maximum likelihood estimation and the extended Kalman filter are applied in the parameter estimation phase. To validate the estimated models, plots......This paper deals with mathematical modelling of the heat transfer of building integrated photovoltaic (BIPV) modules. The efficiency of the photovoltaic (PV) module and its temperature are negatively correlated. It is therefore of interest to lower the temperature of the PV module by increasing...... the heat transfer from the PV module. The experiment and data originate from a test reference module the EC-JRC Ispra. The set-up provides the opportunity of changing physical parameters, the ventilation speed and the type of air flow, and this makes it possible to determine the preferable set...

  4. Modelling the heat dynamics of a monitored Test Reference Environment for Building Integrated Photovoltaic systems using stochastic differential equations

    DEFF Research Database (Denmark)

    Lodi, C.; Bacher, Peder; Cipriano, J.

    2012-01-01

    This paper deals with grey-box modelling of the energy transfer of a double skin Building Integrated Photovoltaic (BIPV) system. Grey-box models are based on a combination of prior physical knowledge and statistics, which enable identification of the unknown parameters in the system and accurate...... and heat transfer coefficients is fundamental in order to improve the thermo-electrical production.The considered grey-box models are composed of a set of continuous time stochastic differential equations, holding the physical description of the system, combined with a set of discrete time measurement...

  5. 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…

  6. Heat storage system adapted for incongruently melting heat storage materials and congruently melting heat storage materials

    Energy Technology Data Exchange (ETDEWEB)

    Schoenfelder, J.L.

    1980-12-30

    A heat storage article adapted for prevention of stratification of incongruently melting heat storage materials, such as eutectic salts, and adapted for use with congruently melting heat storage materials, such as paraffins. The article is comprised of a concrete stone composition, a certain portion of which is comprised of metallic heat transfer materials in order to increase heat transfer through the concrete structure. The concrete structure has an internal cavity which is filled with either the eutectic salt material or the paraffin material.

  7. 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)

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

    DEFF Research Database (Denmark)

    Heller, Alfred

    1996-01-01

    be achieved.The objective of the report is to present results from measured system evaluation andcalculations in detail. In another report R-007 the main results and recommendations aresummed up for non-technicians. The results of the project are among others: The system is rather simple. Much work can...

  9. Estimation of non-linear continuous time models for the heat exchange dynamics of building integrated photovoltaic modules

    DEFF Research Database (Denmark)

    Jimenez, M.J.; Madsen, Henrik; Bloem, J.J.

    2008-01-01

    (MAP) estimation is presented along with a software implementation. As a case study, the modelling of the thermal characteristics of a building integrated PV component is considered. The EC-JRC Ispra has made experimental data available. Both linear and non-linear models are identified. It is shown...

  10. 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 temperatu...... the storage is in its super cooled phase without activation of the phase change. This paper presents an initial simulation model of a PCM storage for implementation in TRNSYS 15 [1] as well as the first test results achieved with the model....

  11. Development of space heating and domestic hot water systems with compact thermal energy storage. Compact thermal energy storage: Material development for System Integration

    NARCIS (Netherlands)

    Davidson, J.H.; Quinnell, J.; Burch, J.; Zondag, H.A.; Boer, R. de; Finck, C.J.; Cuypers, R.; Cabeza, L.F.; Heinz, A.; Jahnig, D.; Furbo, S.; Bertsch, F.

    2013-01-01

    Long-term, compact thermal energy storage (TES) is essential to the development of cost-effective solar and passive building-integrated space heating systems and may enhance the annual technical and economic performance of solar domestic hot water (DHW) systems. Systems should provide high energy st

  12. 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...... (and the the return temperature) would only be a few degrees above room temperature due to the very low heating demand and the large heat transfer surface area. One of the objectives in a newly started IEA Task 32 project is to investigate and develop improved thermal storages for combined solar...... 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...

  13. Optimum heat storage design for SDHWsystems

    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 systems, SDHWsystems. One model is especially designed for traditional SDHWsystems based on a heat storage design where the solar heat exchanger is a built...... analysis of the tank design's influence on the thermal performance of the systems is possible.By means of the calculations design rules for the two heat storage types are proposed....

  14. 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...... of the tank design’s influence on the thermal performance of the systems is possible. By means of the calculations design rules for the two heat storage types are proposed....

  15. Heat storage in alloy transformations

    Science.gov (United States)

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

    1981-01-01

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

  16. 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

  17. Seasonal storage of energy in solar heating

    Science.gov (United States)

    Braun, J. E.; Klein, S. A.; Mitchell, J. W.

    1981-01-01

    This paper focuses on several aspects of seasonal storage for space heating using water as the storage medium. The interrelationships between collector area, storage volume, and system performance are investigated using the transient simulation program TRNSYS. The situations for which seasonal storage is most promising are presented. Particular emphasis is placed upon design of seasonal storage systems. A design method is presented which is applicable for storage capacities ranging from a few days to seasonal storage. This design method, coupled with cost information, should be useful in assessing the economic viability of seasonal storage systems. Also investigated are the importance of the load heat exchanger size, tank insulation, collector slope, and year-to-year weather variations in system design.

  18. Solar Air Heaters with Thermal Heat Storages

    Directory of Open Access Journals (Sweden)

    Abhishek Saxena

    2013-01-01

    Full Text Available 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 been carried out to rate the various thermal energy storage commonly used in solar air heaters. During the investigations rock bed storages have been found to be low type thermal heat storage, while phase change materials have been found to be high heat thermal storages. Besides this, a few other heat storing materials have been studied and discussed for lower to higher ratings in terms of thermal performance purposely for solar heaters.

  19. 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...

  20. Lightweight Thermal Storage Heat Exchangers Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR proposal aims to develop thermal energy storage heat exchangers that are significantly lighter and higher conductance than the present art which involves...

  1. Dish-mounted latent heat buffer storage

    Science.gov (United States)

    Manvi, R.

    1981-01-01

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

  2. Investigation of floor heating with thermal storage

    Institute of Scientific and Technical Information of China (English)

    LIN Zhen-guo; ZHANG Su-yun; FU Xiang-zhao; WANG Yong

    2006-01-01

    Based on experimental data, the energy storage performances of floor radiant heating system were investigated.Based on experimental data, the energy storage performances of floor radiant heating system were investigated. The decrease of indoor air temperature after the stopping of floor heating was compared with that of fan-coil heating system. The increase of indoor air temperature after the stopping of floor cooling system was analyzed. The results show that the floor heating system has good thermal storage performance, which can be used to a night-running model to obtain the energy-saving benefits efficient and economic running cost, and still can be used for "shifting peak load to off-peak" macroscopically.

  3. Application of cross finned tubes in latent heat storages

    Energy Technology Data Exchange (ETDEWEB)

    Schwind, H.; Wolff, D. (Dortmund Univ. (Germany, F.R.). Lehrstuhl fuer Anlagentechnik); Brose, J. (Dortmund Univ. (Germany, F.R.). Arbeitsgruppe Chemieapparatebau)

    1978-01-01

    Heat storages, utilizing the latent heat of materials have in comparison with sensible heat storages the two fundamental advantages of small storage volumes and constant temperatures during charge and discharge. Known storage systems in the field of industrial heating may be replaced advantageous by latent heat storage systems. A new latent heat storage, applying storage material around vertical arranged cross finned tubes is presented. It results in good heat transfer rates and avoids degredation and stratification of salthydrates during operation. The scaling-up of a single cross finned tube to a compact unit with plate fins seems to be practicable without problems. Some experimental results are presented.

  4. Compact seasonal PCM heat storage for solar heating systems

    DEFF Research Database (Denmark)

    Dannemand, Mark

    . 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...... required to keep the graphite suspended and evenly distributed in the SAT composite was also elucidated. Overall, the research has shown that it is possible to utilize stable supercooling of SAT for seasonal heat storage in actual application sized units. Furthermore, investigations have elucidated......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...

  5. 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

  6. Multiple source ground heat storage

    Science.gov (United States)

    Belzile, P.; Lamarche, L.; Rousse, D. R.

    2016-09-01

    Sharing geothermal borefields is usually done with each borehole having the same inlet conditions (flow rate, temperature and fluid). The objective of this research is to improve the energy efficiency of shared and hybrid geothermal borefields by segregating heat transfer sources. Two models are briefly presented: The first model allows the segregation of the inlet conditions for each borefields; the second model allows circuits to be defined independently for each leg of double U-tubes in a borehole. An application couples residential heat pumps and arrays of solar collectors. Independent circuits configuration gave the best energy savings in a symmetric configuration, the largest shank spacing and with solar collectors functioning all year long. The boreholes have been shortened from 300 m to 150 m in this configuration.

  7. Solar Thermoelectricity via Advanced Latent Heat Storage

    Energy Technology Data Exchange (ETDEWEB)

    Olsen, Michele L.; Rea, J.; Glatzmaier, Greg C.; Hardin, C.; Oshman, C.; Vaughn, J.; Roark, T.; Raade, J. W.; Bradshaw, R. W.; Sharp, J.; Avery, Azure D.; Bobela, David; Bonner, R.; Weigand, R.; Campo, D.; Parilla, Philip A.; Siegel, N. P.; Toberer, Eric S.; Ginley, David S.

    2016-05-31

    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.

  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. Thermochemical heat storage - system design issues

    NARCIS (Netherlands)

    Jong, A.J. de; Trausel, F.; Finck, C.J.; Vliet, L.D. van; Cuypers, R.

    2014-01-01

    Thermochemical materials (TCMs) are a promising solution for seasonal heat storage, providing the possibility to store excess solar energy from the warm season for later use during the cold season, and with that all year long sustainable energy. With our fixed bed, vacuum reactors using zeolite as T

  10. Thermochemical heat storage - system design issues

    NARCIS (Netherlands)

    Jong, A.J. de; Trausel, F.; Finck, C.J.; Vliet, L.D. van; Cuypers, R.

    2014-01-01

    Thermochemical materials (TCMs) are a promising solution for seasonal heat storage, providing the possibility to store excess solar energy from the warm season for later use during the cold season, and with that all year long sustainable energy. With our fixed bed, vacuum reactors using zeolite as

  11. A study of the heating and heat storage problems in passive solar heated room with greenhouse

    Institute of Scientific and Technical Information of China (English)

    CHENWei; LIUWei

    2003-01-01

    In this paper, heating and heat storage in passive solar heating room with greenhouse has been studied. The unsteady numerical simulation is employed to analyze the performance of the flow and temperature field for the typical sunny day of Wuhan, China, in winter in the heating system. The floor of passive solar heating room with a convective hole or not has great effects on temperature distribution and gas flow in heat storage layer of this system. Properties of the bed worked as solar absorber and storage layer have also been studied.

  12. Technologies for building integrated energy supply; Teknologier for bygningsintegreret energiforsyning

    Energy Technology Data Exchange (ETDEWEB)

    Katic, I.

    2011-07-15

    The current report is part of the deliverables from the project ''Building Integrated Energy Supply'' supported by the Danish Energy Authority R and D program. It describes a range of technologies for individual supply of heat and/or electricity to dwellings with respect to their stage of development and possible application in the near future. Energy supply of buildings is becoming more and more complex, partly as a result of increasing demands for comfort, efficiency and reduced emissions, partly as a result of rising oil prices and improved competitiveness of alternative energy sources. The days where ordinary boilers were the dominant source of individual supply of dwellings are becoming past these years. The challenge of the new range of technologies lies to a high extent in the fluctuating nature of their energy conversion and their interaction with the supply grids for heat and electricity. There is thus an increasing demand to understand the nature of the different supply technologies, besides a regular update of their economical key figures. The technologies briefly described in this study are: Solar heating, passive solar energy, biofuel boilers, heat pumps, micro CHP, solar photovoltaic and energy storage systems. The selected technologies are all assessed to play an important role in future's mix of supply technologies in Denmark, especially heat pumps and solar. (Author)

  13. A solar heating system with annual storage

    Science.gov (United States)

    Lazzari, F.; Raffellini, G.

    1981-07-01

    A solar heated house with long term storage capability, built in Trento, Italy, is described. The one story house was built from modular components and has a total heated volume of 1130 cu m. Flat plate solar collectors with a water-antifreeze medium are located beneath the lawn, and six cylindrical underground tanks holding 130 cu m of water heated by thermal energy from the collectors are situated under the garden. The house walls have an 8 cm cavity filled with 5 cm of formaldehyde foam, yielding a heat transmission (U) of 0.37 W/sq m/deg C. The roof and ceilings are insulated with fiberglass and concrete, producing U-values of 0.46 W/sq m/deg C and 0.57 W/sq m/deg C, respectively. Heat pumps using 6 kW move thermal energy between the house and the tanks. Direct hot water heating occurs in the summer, and direct home heating when the stored water temperature exceeds 32 C. A computer model was developed which traces the annual heat flow and it is shown that the system supplies all heating requirements for the house, with electrical requirements equal to 20 percent of the annual house needs.

  14. Transient response of latent heat storage in greenhouse solar system

    Energy Technology Data Exchange (ETDEWEB)

    Huang, B.K.; Toksoy, M.; Cengel, Y.A.

    1986-01-01

    A latent heat storage system with two different stacking configurations and air bafflings was designed and constructed as an integrated part of the greenhouse solar system (solar barn). Commercial cylindrical storage rods were used as the primary storage elements. The results showed that the designed latent storage systems demonstrated significantly higher compact storage capacity than water or rock storage and that the ring-baffled storage unit performed better than the cross-baffled storage unit.

  15. Solar reflector and heat storage device

    Energy Technology Data Exchange (ETDEWEB)

    Conger, S.J.

    1982-07-06

    A passive solar system is disclosed having a plurality of heat storage trays mounted adjacent to a window and arranged to absorb relatively low angled radiation and to reject relatively high angled radiation while providing a substantially unobstructed view through the window. The trays have their reflective upper surfaces angled toward the window and their absorptive lower surfaces angled toward the room. A phase change heat storage material is disposed between the upper and lower surfaces. In one configuration the lower surface is corrugated having one set of generally absorptive surface faces facing the reflective upper surface of an adjacent tray and having another set of generally emissive surface faces facing the interior of the room.

  16. Transient response of latent heat storage in greenhouse solar system

    Energy Technology Data Exchange (ETDEWEB)

    Huang, B.K.; Cengel, Y.A.; Toksoy, M.

    1983-06-01

    A latent heat storage system with two different stacking configurations and air bafflings was designed and constructed as an integrated part of the greenhouse solar system. Commercial cylindrical storage rods were used as the primary storage elements. The results showed that the latent storage system performed significantly better than water or rock storage.

  17. Central solar heating plants with seasonal storage

    Energy Technology Data Exchange (ETDEWEB)

    Breger, D.S.; Sunderland, J.E.

    1989-03-01

    The University of Massachusetts has recently started a two year effort to identify and design a significant Central Solar Heating Plant with Seasonal Storage (CSHPSS) in Massachusetts. The work is closely associated with the U.S. participation in the International Energy Agency (IEA) Task on CSHPSS. The University is working closely with the Commonwealth of Massachusetts to assist in identifying State facilities as potential sites and to explore and secure State support which will be essential for product development after the design phase. Currently, the primary site is the University of Massachusetts, Amherst campus with particular interest in several large buildings which are funded for construction over the next 4-5 years. Seasonal thermal energy storage will utilize one of several geological formations.

  18. Research and Development Needs for Building-Integrated Solar Technologies

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2014-01-01

    The Building Technologies Office (BTO) has identified Building Integrated Solar Technologies (BIST) as a potentially valuable piece of the comprehensive pathway to help achieve its goal of reducing energy consumption in residential and commercial buildings by 50% by the year 2030. This report helps to identify the key research and development (R&D) needs that will be required for BIST to make a substantial contribution toward that goal. BIST include technologies for space heating and cooling, water heating, hybrid photovoltaic-thermal systems (PV/T), active solar lighting, and building-integrated photovoltaics (BIPV).

  19. Thermal storage technologies for solar industrial process heat applications

    Science.gov (United States)

    Gordon, L. H.

    1979-01-01

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

  20. Optimal Day-to-Night Greenhouse Heat Storage

    NARCIS (Netherlands)

    Seginer, Ido; Straten, van Gerrit; Beveren, van Peter

    2016-01-01

    Day-to-night heat storage is often practiced in cold-climate greenhouses. It is suggested to manage the heat storage by considering the co-state (virtual value) of the stored heat in the on-line optimization of the greenhouse environment. Examples worked out for a periodic square-wave weather show t

  1. 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

  2. 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

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

    OpenAIRE

    Klimes Lubomir; Mauder Tomas; Ostry Milan; Charvat Pavel

    2012-01-01

    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...

  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...... are theoretically investigated by Computational Fluid Dynamics (CFD) calculations. The heat transfer rates between the PCM storage and the heating fluid/cooling fluid in the plate heat exchangers are determined. The CFD calculated temperatures are compared to measured temperatures. Based on the studies...

  5. Thermal energy storage for industrial waste heat recovery

    Science.gov (United States)

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

    1978-01-01

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

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

    Science.gov (United States)

    Charvat, Pavel; Ostry, Milan; Mauder, Tomas; Klimes, Lubomir

    2012-04-01

    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).

  7. 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.

  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

    including pipe spacing, storage materials, and distribution of insulation around the thermal storage layer. The energy consump-tion, reduction due to the heat storage and total performance of the solar heating system was calculated. The largest reduction of 100 kWh/m² solar collector occurred in the house...... 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......In this paper, heat storage of solar heating in the floor construction of single-family houses is examined. A floor construction with two concrete decks is investigated. The lower is used as heat storage while the upper deck has a floor heating system. The potential for a reduction of the energy...

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

    Energy Technology Data Exchange (ETDEWEB)

    Lee, S.Y.

    1999-01-13

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

  10. Evaluation of thermal energy storage for the proposed Twin Cities District Heating system. [using cogeneration heat production and aquifiers for heat storage

    Science.gov (United States)

    Meyer, C. F.

    1980-01-01

    The technical and economic feasibility of incorporating thermal energy storage components into the proposed Twin Cities District heating project was evaluated. The technical status of the project is reviewed and conceptual designs of district heating systems with and without thermal energy storage were compared in terms of estimated capital requirements, fuel consumption, delivered energy cost, and environmental aspects. The thermal energy storage system is based on cogeneration and the storage of heat in aquifers.

  11. 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...... 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...... important step. Adding heat storages only moderately reduces the fuel consumption. Model development has been made to facilitate a technical optimisation of individual heat pumps and heat storages in integration with the energy system....

  12. NUMERICAL ANALYSIS OF HEAT STORAGE OF SOLAR HEAT IN FLOOR CONSTRUCTION

    DEFF Research Database (Denmark)

    Weitzmann, Peter; Holck, Ole; Svendsen, Svend

    2003-01-01

    In this paper, heat storage of solar heating in the floor construction of single-family houses is examined. A floor construction with two concrete decks is investigated. The lower is used as heat storage while the upper deck has a floor heating system. The potential for a reduction of the energy...... consumption for heating, by using heat storage in the floor construction is calculated using a dynamic simulation model of solar collector, solar tank and heat storage coupled to a building model, using the Danish Design Ref-erence Year as input. The model calculates the performance of the solar heating...... system room temperature and energy consumption. A single-family house with and without heat recovery unit on the ventilation system of 130 m² with heating demand of approximately 70 kWh/m² and 40 kWh/m² is investigated. A parametrical analysis was performed for the solar collector area, and floor layouts...

  13. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-04-01

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

  15. Design and simulation of latent heat storage units

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-04-01

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

  16. 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...... in the heating system. The heat storage was tested in a heat storage test facility. The most important characteristics of the heat storage were determined by means of the tests and recommendations for the design of the heat storage were given....

  17. Analysis of flow and heat transfer characteristics of porous heat-storage wall in greenhouse

    Institute of Scientific and Technical Information of China (English)

    Li OUYANG; Wei LIU

    2008-01-01

    The flow and heat transfer characteristics of porous heat-storage wall in greenhouse are studied by using the one-dimensional steady energy two-equation model for saturated porous medium. The results show that the heat exchange between the air and the solid matrix of the porous heat-storage wall depends upon the inlet air velocity, the porosity and the permeability of porous medium, and the thermal conductivity of the solid matrix. Because the incidence of solar radiation on the porous heat-storage wall is not uniform, the new compos-ite porous solar wall with different porosity is proposed to reduce the disadvantageous effect.

  18. Latent Heat storage characteristics of solid-liquid phase change Heat Storage Microcapsule Slurry by Boiling Heat Transfer under a Vacuum Condition

    Science.gov (United States)

    Inaba, Hideo; Horibe, Akihiko; Haruki, Naoto; Katayama, Masatoshi; Manabe, Ken

    Recently, the new heat transfer medium, which fulfills both functions of heat storage and heat transportation, has been developed in ah eat storage field. Solid-liquid latent heat microcapsule slurry would correspond to the topical medium, so-called functionally thermal fluid. The preset study has clarified the latent heat storage characteristics of microcapsule slurry by making heat transfer enlargement with the help of slurry water pool boiling phenomenon. The paraffin wax at a melting point of 62°C was used as a phase change material which was packed into the microcapsule. The heating surface temperature and concentration of paraffin in the microcapsule slurry was selected as experimental parameters. As a result, the non-dimensional correlation equations of heat storage completion time and heat transfer were derived in terms of non-dimensional parameters.

  19. Layout of a latent heat storage system with finned tubes

    Energy Technology Data Exchange (ETDEWEB)

    Wolff, D.

    1980-10-26

    The theoretical and experimental investigations show by the example of Glauber's salt in a finned-tube latent heat storage vessel how heat transfer and storage capacity at charging and discharging depend on the variables of geometry, temperature, time and on the composition of the storing medium. By vertical arrangement of transversely finned tubes the separation problems occurring with Glauber's salt are solved insofar as the technical utilization of the latent heat of conversion corresponding to the complete conversion during charging and discharging not being possible, no decrease, of the reduced storage capacity, however, is found even after very many charging/discharging cycles. For the heat transfer during discharging correlations can be given on the basis of a model concept, be means of which a heat transfer coefficient, varying during the discharging process, can be predicted almost for the total range of discharge as a function of geometry, temperature and state of discharge. On the basis of the simple working formula for the heat transfer coefficient at crystallization of a latent heat storing medium the dynamic behavior of a compact finned-tube storage vessel can be predicted by means of a computer code. These means allow to perform the thermal design of a compact latent heat storage facility according to given design criteria accounting for economic aspects.

  20. 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 tem

  1. 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 tem

  2. Thermochemical heat storage. State-of-the-art report

    Energy Technology Data Exchange (ETDEWEB)

    Oelert, G.; Behret, H.; Friedel, W.; Hennemann, B.; Hodgett, D.; Purper, G.; Nelson, B.; Westermark, M.

    1982-01-01

    In practically all areas of energy conservation R and D (solar, waste heat, heat pumps, production processes) the storage of energy has been identified as a critical requirement in the optimization of systems. The energy storage densities theoretically achievable in thermochemical storage are much higher than those of sensible or latent heat storage and furthermore, thermochemical heat storage (TCHS), in contrast to the two former techniques, has been considered in the past to be theoretically free of heat losses. This project was designed to: characterize the major areas of possible TCHS use in Sweden; analyze the state of TCHS development worldwide; assess the prospects of TCHS in Sweden; and identify TCHS R and D needs as complementary efforts within energy conservation development. The approach, background, and the chemical, technical and social/economical investigations as well as the overall assessment of TCHS technology and the R and D recommendations are compiled in this report. The result of the study shows that the economy for long term thermochemical heat storage is not very favorable. However, this is true for any long term storage under the assumption that oil will be available at a reasonable price even at the end of this century. If by then oil is not available at all for heating of buildings, it is important to know what other systems can possibly be used. An important conclusion of the study is that practical design problems have often been underestimated. It is also clear that it could still be worthwhile to continue work on some systems.

  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

    2014-01-01

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

  4. 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.

  5. Seasonal heat storage in cogeneration systems; Saesongvaermelager i kraftvaermesystem

    Energy Technology Data Exchange (ETDEWEB)

    Zinko, Heimo; Gebremedhin, Alemayehu

    2007-07-01

    There is a rising interest in Sweden for the use of cogeneration power plants in district heating networks, generating both electricity and heat in a coupled operation. This type of cogeneration needs, however, the existence of suitable heat loads. In this study we investigate the use of large long-term heat storages for the cases that the DH-load is not sufficient. For this purpose, the technology of long-term storages is also reviewed based on the know-how developed for solar heating plants at the end of 20th century. Long-term storages have been developed around the 1980s and 1990s. The storages have been built as pits in the ground or as caverns for the storage of hot water or as borehole storages and aquifers for heat storages in rock or ground material. In this report, the different techniques are described and operational experiences from Sweden and Germany are summarised. Furthermore, the storage costs for the different techniques are presented. In order to be of interest for application in cogeneration systems, it is necessary that the storage allows charging and discharging with high heat capacities. The most suitable storage type for that purpose is a rock cavern, which can be constructed in volumes up to millions of m3 water with reasonable costs, as demonstrated in the 1970s with strategic oil storages. Another interesting storage type is the borehole ground storage, as used in solar heating plants. However, in the application for cogeneration, this storage type must be further developed towards higher heat transfer rates. For the analysis of storage applications in cogeneration systems, a number of operational cases from real cogeneration systems in Enkoeping and in Linkoeping have been studied. Models have been developed for calculation in Excel and operational years have been simulated and economically evaluated with different storage sizes. The following basic systems have been analysed: a) System with biofuel-fired cogeneration and biofuel top

  6. Building-integrated renewable energy policy analysis in China

    Institute of Scientific and Technical Information of China (English)

    姚春妮; 郝斌

    2009-01-01

    With the dramatic development of renewable energy all over the world,and for purpose of adjusting energy structure,the Ministry of Construction of China plans to promote the large scale application of renewable energy in buildings. In order to ensure the validity of policy-making,this work firstly exerts a method to do cost-benefit analysis for three kinds of technologies such as building-integrated solar hot water (BISHW) system,building-integrated photovoltaic (BIPV) technology and ground water heat pump (GWHP). Through selecting a representative city of every climate region,the analysis comes into different results for different climate regions in China and respectively different suggestion for policy-making. On the analysis basis,the Ministry of Construction (MOC) and the Ministry of Finance of China (MOF) united to start-up Building-integrated Renewable Energy Demonstration Projects (BIREDP) in 2006. In the demonstration projects,renewable energy takes place of traditional energy to supply the domestic hot water,electricity,air-conditioning and heating. Through carrying out the demonstration projects,renewable energy related market has been expanded. More and more relative companies and local governments take the opportunity to promote the large scale application of renewable energy in buildings.

  7. 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

  8. Preparation and characterizations of heat storage material combining porous metal with molten salt

    Institute of Scientific and Technical Information of China (English)

    王华; 何方; 戴永年; 胡建杭

    2003-01-01

    A new type of heat storage materials combining high temperature molten salts phases change latent heat thermal storage materials, PCM with porous metals sensible heat thermal storage materials was developed. The process was expressed as following: firstly, it is necessary to heat up the molten salts phases change materials to molten; and then the porous metals are put into the molten bath; after being held for 1-3 h, the composite heat thermal storage materials lumps are taken out of the molten bath and cooled to atmospheric temperature; the last step is to electrodeposit a layer metal coat on the surface of the material lumps. The new type of heat storage material integrates the advantages of both solid sensible heat thermal storage materials and high temperature phases change latent heat thermal storage materials. The metal-base heat storage materials enjoy some favorable characteristics such as higher heat charge-discharge rate, higher heat storage density and better mechanical strength.

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

    Science.gov (United States)

    Sakitani, Katsumi; Honda, Hiroshi

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

  10. Study of Heat Transfer in Ice-storage Tank

    Institute of Scientific and Technical Information of China (English)

    Anding He; Huanqun Qian; Zhihua Hu; Fangde Zhou

    2001-01-01

    The heat transfer process of ice formation on the outside of coil pipe in the ice storage tank with glycol solution as the second refrigerant was studied in this paper analytically and experimentally. A model was developed for the charging process and the conduction shape factor was applied. Also, the result obtained from the model was compared with the experimental data, both data were in agreement. The simple model is useful for the operation, design and optimization of the ice storage tank.

  11. Heat loading limits for solid transuranic wastes storage

    Energy Technology Data Exchange (ETDEWEB)

    Spatz, T.L.

    1993-07-01

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

  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

    . In long periods with high level of irradiance several modules were charged in parallel due to the limited heat exchange capacity of the integrated heat exchanger of the modules. After the modules were heated to more than 80° C they were set to passively cool down. Modules reached 30 °C in a period......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. Copper-Silicon-Magnesium Alloys for Latent Heat Storage

    Science.gov (United States)

    Gibbs, P. J.; Withey, E. A.; Coker, E. N.; Kruizenga, A. M.; Andraka, C. E.

    2016-12-01

    The systematic development of microstructure, solidification characteristics, and heat of solidification with composition in copper-silicon-magnesium alloys for thermal energy storage is presented. Differential scanning calorimetry was used to relate the thermal characteristics to microstructural development in the investigated alloys and clarifies the location of one of the terminal three-phase eutectics. Repeated thermal cycling highlights the thermal storage stability of the transformation through multiple melting events. Two near-terminal eutectic alloys display high enthalpies of solidification, relatively narrow melting ranges, and stable transformation hysteresis behaviors suited to thermal energy storage.

  14. Energy saving potential of semi-transparent photovoltaic elements for building integration

    OpenAIRE

    Olivieri, Lorenzo; Caamaño Martín, Estefanía; Moralejo Vázquez, Francisco José; Martín Chivelet, Nuria; Olivieri, Francesca; Neila Gonzalez, Francisco Javier

    2014-01-01

    Within the building energy saving strategies, BIPV (building integrated photovoltaic systems) present a promising potential based on the close relationship existing between these multifunctional systems and the overall building energy balance. Building integration of STPV (semi-transparent photovoltaic) elements affects deeply the building energy demand since it influences the heating, cooling and lighting loads as well as the local electricity generation. This work analyses over different wi...

  15. 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

    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...... 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...

  16. Swiss energy research programme on solar heat and storage for 2008-2011; Programme de recherche energetique. Chaleur solaire et stockage pour la periode 2008-2011

    Energy Technology Data Exchange (ETDEWEB)

    Hadorn, J.-C.

    2009-07-15

    This report published by the Swiss Federal Office of Energy (SFOE) takes a look at the research programme on solar heat and heat storage for the years 2008 - 2011. This document presents some aspects of the solar thermal market in 2007, summarizes the main solar thermal technologies for buildings and sketches the main topics of the 'Solar Heat and Heat Storage' research programme. Research and development issues looked at focus mainly on the heating and cooling of buildings. The research and development issues for solar thermal technologies during the period 2008-2011 include improved performance and durability of solar collectors and components, new coatings for solar collectors based on nano-materials as well as simplified and standardised systems for solar heating and cooling. Building Integration and integration in existing heating systems and long-term work with a focus on new materials for storing heat for use in residential buildings are discussed. Also, calculation methods and simulation tools are examined. Pilot and demonstration projects are reviewed.

  17. Comparison of multitank storage DHW heating solar plants

    Energy Technology Data Exchange (ETDEWEB)

    Lazzarin, R.; Rossetto, L.; Schibuola, L.

    1983-04-01

    Distribution of the hot storage in a multitank system may be a suitable way to assure stratification in DHW solar heating plants of medium and great sizes. The possible connections for the various tanks are manifold: three different working ways are considered in this paper. Performances are analyzed during one year through TRNSYS computing program and the results are compared.

  18. 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

  19. 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 using water tanks (buffers) is common practice in cold-climate greenhouses, where gas is burned during the day for carbon dioxide enrichment. In this study an optimal control approach is outlined for such a system, based on the idea that the virtual value (shadow price) of

  20. Maximizing Storage Flexibility in an Aggregated Heat Pump Portfolio

    DEFF Research Database (Denmark)

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

    2014-01-01

    To balance the electrical grid due to a large increase in the renewable energy production mainly from wind turbines will be a problem in the near future in Denmark. Smart grid solutions with new storage capacities are essential. In this work single family houses with heat pumps are investigated...

  1. Thermal energy storage - overview and specific insight into nitrate salts for sensible and latent heat storage.

    Science.gov (United States)

    Pfleger, Nicole; Bauer, Thomas; Martin, Claudia; Eck, Markus; Wörner, Antje

    2015-01-01

    Thermal energy storage (TES) is capable to reduce the demand of conventional energy sources for two reasons: First, they prevent the mismatch between the energy supply and the power demand when generating electricity from renewable energy sources. Second, utilization of waste heat in industrial processes by thermal energy storage reduces the final energy consumption. This review focuses mainly on material aspects of alkali nitrate salts. They include thermal properties, thermal decomposition processes as well as a new method to develop optimized salt systems.

  2. Customer attitudes toward thermal-energy-storage heating

    Science.gov (United States)

    Hersh, H. N.

    1981-06-01

    Attitudes among users of thermal energy storage (TES) heating systems were studied. A customer acceptance survey exploring attitudes and levels of satisfaction, face to face contacts between utility representatives and users, and a survey of pertinent published information are investigated. It is found that: (1) TES heating systems are installed for economic reasons by customers who can afford higher initial costs and understand the concept of lower total cost; and (2) attitudes toward TES are positive. The TES systems are not regarded more favorably than conventional systems, however, and it is likely that lower electric heating bills are responsible for the favorable perceptions of most TES users.

  3. Building integrated photovoltaic; Photovaltaique integre aux batiments

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-01-01

    Durable, modular and flexible in use, as demonstrated by the different case studies in this publication, photovoltaic can replace diverse building elements, from glass facades to weather proof roofs. This leaflet towards architects describes aesthetic, technical, economic and environmental interest of building integrated photovoltaic. (author)

  4. 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.

  5. Study on cascade type underground heat storage, solar space heating system in Tehran (Part 2)

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Yasutaka; Kaabi-Nejadian, A.; Ito, Yukio

    1987-12-01

    This paper describes the cascade type underground heat storage, solar space-heating system using capsule-form latent heat storage material in Tehran. The coefficient of performance of the system and a used heat pump (HP), the solar collecting efficiency, and the effect of six variation factors on heat recovery from soil were subjected to variance analysis. For the heat recovery from soil, the operation time of HP was significant. For the solar collecting efficiency, the collector area was significant. As for short-period thermal behaviours, two operations of the system different in HP operation time on February 7th were sampled. The wind quantity and operation time of the space-heating fan, though they were not statistically significant, were effective for space-heating depending on thermal load to the system, since the fan can supply a large quantity of heat for space-heating. The temperature of the Kernel tank, the intermediate tank (latent heat), and the outermost tank (sesible heat) was decreased in that order. The temperture of the outermost tank was remarkably decreased during HP operation, so that heat-recovery was conducted. (5 figs, 4 tabs, 3 refs)

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

    Science.gov (United States)

    Chang, Ming-, Jr.

    1991-02-01

    Future space missions will require thermal transport devices with the ability to handle transient pulse heat loads. A novel design of a high-temperature axially grooved heat pipe (HP) which incorporates thermal energy storage (TES) to migrate pulse heat loads was presented. A phase-change material (PCM) which is encapsulated in cylindrical containers was used for the thermal energy storage. The transient response of the HP/TES system under two different types of pulse heat loads was studied analytically. The first type is pulse heat loads applied at the heat pipe evaporator, the second type is reversed-pulse heat loads applied at the condenser. In this research, a new three-dimensional alternating-direction-implicit (ADI) method was developed to model the heat conduction through the heat pipe wall and wicks, including the liquid flow in grooves. A very important characteristic of this new ADI method is that it is consistent with physical considerations. Compared with the well-known Brian's and Douglas's ADI methods, this new ADI method had higher accuracy and requires less computer storage. In the numerical solution of heat transfer problems with phase change (Stefan-type problem), a modified Pham's method which includes features from enthalpy and heat capacity methods was used to simulate the melting and solidification processes of the PCG. The vapor flow was assumed quasi-steady and one-dimensional, and was coupled with the evaporation and condensation on the heat pipe inside wall surface and the surfaces of the PCM containers. The transient responses of three different HP/TES configurations were compared: (1) a heat pipe with a large empty cylinder installed in the vapor core, (2) a heat pipe with a large PCM cylinder, and (3) a heat pipe with six small PCM cylinders. From the numerical results, it was found that the PCM is very effective in mitigrating the adverse effect of pulse heat loads. The six small PCM cylinders are more efficient than the large PCM

  7. 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 (relea

  8. 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.

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

    OpenAIRE

    Finck, C.J.; Henquet, E.M.R.; Soest, C.F.L. van; Oversloot, H.P.; de Jong, A. J.; 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 (released by adsorption) of 20 – 51 K which is by all means suitable for space heating.

  10. 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

  11. Isobaric gas and steam. Compressed air storage power plant with heat storage system; Isobares GuD. Druckluftspeicherkraftwerk mit Waermespeicher

    Energy Technology Data Exchange (ETDEWEB)

    Nielsen, Lasse; Leithner, Reinhard; Qi, Dawei [Technische Univ. Braunschweig (Germany). Inst. fuer Waerme- und Brennstofftechnik; Grote, Wolfgang; Kastsian, Darya; Moennigmann, Martin [Bochum Univ. (Germany). Lehrstuhl fuer Regelungstechnik und Systemtheorie

    2011-07-01

    The ISACOAST-CC (Isobaric Adiabatic Compressed Air Energy Storage - Combinde Cycle) is a innovative combination of combined cycle power plant, compressed air store and heat store. First calculations show that a storage efficiency of 80 % could be achieved.

  12. Study on the Effect of Ground Heat Storage by Solar Heat Using Numerical Simulation

    Directory of Open Access Journals (Sweden)

    Jin-Hwan Oh

    2015-12-01

    Full Text Available Recently, energy storage techniques using renewable energy efficiently have attracted considerable attention. However, there are several problems when using renewable energy. In the case of solar energy, the energy production time is different from the consumption time, and the use of geothermal energy has high investment costs. In order to solve these problems, it is essential to develop high-efficiency systems using both solar and geothermal energy simultaneously and efficiently. Thus, in this study, the performance of underground heat storage of solar energy was examined by simulation using models of underground heat transfer and heat exchange for the development of an integrated hybrid system exploiting both geothermal and solar energy. As a result, the heat extraction performance was determined to be up to 72.75 W/m. As a result, in Kagoshima, the most southern area in Korea, a case of six hour heat storage operation achieved the highest heat exchange rate of 72.75 W/m, which is approximately 105% higher than the case of operation without heat storage.

  13. 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.

  14. 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 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 262-284/MWh for batteries and $172-254/MWh for Compressed Air Energy Storage.

  15. 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.

  16. 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.

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

    CSIR Research Space (South Africa)

    Majozi, T

    2010-10-01

    Full Text Available feasibility constraint ensuring that if a unit is not integrated with heat storage, the associated duty should not exist. ( ) ),,()(),(max),,(),,( ,,,,, , puszsEsEpusQpusz jinjinjin s jinjin hcjin ≤≤δ UuSssPp jinjinjin hc ∈∈∈∀ ,,, ,,, (8...) ensure that the times at which units are active are synchronised when direct heat integration takes place. Starting times for the tasks in the integrated units are the same. ( )),,(1),(),( ,,,, pssxMpstpst hcch jinjinjinujinu −−≥ jinjinjin Sss...

  18. Thermal energy storage systems using fluidized bed heat exchangers

    Science.gov (United States)

    Ramanathan, V.; Weast, T. E.; Ananth, K. P.

    1980-01-01

    The viability of using fluidized bed heat exchangers (FBHX) for thermal energy storage (TES) in applications with potential for waste heat recovery was investigated. Of the candidate applications screened, cement plant rotary kilns and steel plant electric arc furnaces were identified, via the chosen selection criteria, as having the best potential for successful use of FBHX/TES system. A computer model of the FBHX/TES systems was developed and the technical feasibility of the two selected applications was verified. Economic and tradeoff evaluations in progress for final optimization of the systems and selection of the most promising system for further concept validation are described.

  19. 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.

  20. 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

    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....

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

    Energy Technology Data Exchange (ETDEWEB)

    Fthenakis, V.; Leigh, R.

    1981-12-01

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

  2. 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

    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...... 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...

  3. 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.

  4. 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....... • 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...... 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...

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

    Science.gov (United States)

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

    1981-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Tuncbilek, K.; Sari, A. [Gaziosmanpasa Univ., Tokat (Turkey). Dept. of Chemistry; Tarhan, S.; Erguenes, G. [Gaziosmanpasa Univ., Tokat (Turkey). Dept. of Agricultural Machinery; Kaygusuz, K. [Karadeniz Technical Univ., Trabzon (Turkey). Dept. of Chemistry

    2005-04-01

    Palmitic acid (PA, 59.8 {sup o}C) and lauric acid (LA, 42.6 {sup o}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 {sup o}C and the latent heat of fusion of 166.3 J g{sup -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. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Kadir Tuncbilek; Ahmet Sari [Gaziosmanpasa University, Tokat (Turkey). Dept. of Chemistry; Sefa Tarhan; Gazanfer Ergunes [Gaziosmanpasa University, Tokat (Turkey). Dept. of Agricultural Machinery; Kamil Kaygusuz [Karadeniz University, Trabzon (Turkey). Dept. of Chemistry

    2005-04-01

    Palmitic acid (PA, 59.8{sup o}C) and lauric acid (LA, 42.6{sup o}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 {sup o}C and the latent heat of fusion of 166.3 J g{sup -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. (author)

  8. 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...

  9. Development of composite latent/sensible heat storage media

    Science.gov (United States)

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

    1990-12-01

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

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

    Directory of Open Access Journals (Sweden)

    Borislav Bogdanović

    2009-01-01

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

  11. High temperature metal hydrides as heat storage materials for solar and related applications.

    Science.gov (United States)

    Felderhoff, Michael; Bogdanović, Borislav

    2009-01-01

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

  12. 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...

  13. Thermal storage for industrial process and reject heat

    Science.gov (United States)

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

    1978-01-01

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

  14. Non-equilibrium thermochemical heat storage in porous media

    DEFF Research Database (Denmark)

    Nagel, T.; Shao, H.; Singh, Ashok

    2013-01-01

    Thermochemical energy storage can play an important role in the establishment of a reliable renewable energy supply and can increase the efficiency of industrial processes. The application of directly permeated reactive beds leads to strongly coupled mass and heat transport processes that also...... compressible gas flow through a porous solid is presented along with its finite element implementation where solid-gas reactions occur and both phases have individual temperature fields. The model is embedded in the Theory of Porous Media and the derivation is based on the evaluation of the Clausius...

  15. Nanoparticles for heat transfer and thermal energy storage

    Energy Technology Data Exchange (ETDEWEB)

    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.

  16. 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.

  17. 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)

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. Investigation of methods to transfer heat from solar liquid-heating collectors to heat storage tanks. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Horel, J. D.; de Winter, F.

    1978-04-20

    A study was made of the methods available to transfer heat from the collector to the water storage tank in water heating systems. In counterflow heat exchangers used in double loop water heating systems, it was found to be more important to use a high water flowrate than a high heat transfer fluid flowrate. It was earlier thought to be best to have matched WC/sub p/ (mass flowrate-specific heat) products in the loops. It was shown in this study that the water WC/sub p/ product should be about twice as large as that of the heat transfer fluid. It was found that neither the heat exchanger type nor the size was very critical, so that very simple criteria were adequate in determining optimum heat exchanger size. It was found that there is a definite system size below which one should use a traced tank or a coil in a tank. Equations and optimization criteria were developed for traced tanks or tanks with coils. At present, there is no quantitative understanding of liquid to liquid (direct contact) heat exchangers, though they are clearly quite effective. Draindown systems are discussed, and several appendices are included on heat transfer and other characteristics of fluid and of equipment.

  3. 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.

  4. Packed bed heat storage: Continuum mechanics model and validation

    Science.gov (United States)

    Knödler, Philipp; Dreißigacker, Volker; Zunft, Stefan

    2016-05-01

    Thermal energy storage (TES) systems are key elements for various types of new power plant concepts. As possible cost-effective storage inventory option, packed beds of miscellaneous material come into consideration. However, high technical risks arise due to thermal expansion and shrinking of the packed bed's particles during cyclic thermal operation, possibly leading to material failure. Therefore, suitable tools for designing the heat storage system are mandatory. While particle discrete models offer detailed simulation results, the computing time for large scale applications is inefficient. In contrast, continuous models offer time-efficient simulation results but are in need of effective packed bed parameters. This work focuses on providing insight into some basic methods and tools on how to obtain such parameters and on how they are implemented into a continuum model. In this context, a particle discrete model as well as a test rig for carrying out uniaxial compression tests (UCT) is introduced. Performing of experimental validation tests indicate good agreement with simulated UCT results. In this process, effective parameters required for a continuous packed bed model were identified and used for continuum simulation. This approach is validated by comparing the simulated results with experimental data from another test rig. The presented method significantly simplifies subsequent design studies.

  5. 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...

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

    DEFF Research Database (Denmark)

    Schultz, Jørgen Munthe; Furbo, Simon

    2005-01-01

    and xanthane rubber. The storage can cool down to surrounding temperature preserving the latent heat in form of the heat of fusion energy. The basis for the calculations is a super low energy house with a space heating demand of 2010 kWh/year and a domestic hot water demand of 2530 kWh/year. For storage...

  7. 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

  8. 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

    This paper investigates heat storage and cooling concept that utilizes both phase change material (PCM) and a thermal active building system (TABS) implemented in a hollow core concrete deck element. PCMs are promising materials for improving the heat storage capacity of a building due...... 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...

  9. Quality of shell eggs pasteurized with heat or heat-ozone combination during extended storage.

    Science.gov (United States)

    Perry, J J; Rodriguez-Saona, L E; Yousef, A E

    2011-09-01

    The physical quality and functionality of shell eggs, pasteurized with heat or a combination of heat and ozone, were assessed during eight weeks of storage at 4 or 25 °C. Shell eggs were treated as follows: (1) immersion heating that mimics commercial pasteurization processes (egg internal temperature of 56 ± 0.1 °C for 32 min), or (2) a newly developed combination process comprised of heating (56 ± 0.1 °C, internal, for 10 min) followed by gaseous ozone treatment. Eggs were tested for yolk index, Haugh units, albumen pH, albumen turbidity, and percent overrun. Additionally, albumen samples were assayed for lysozyme activity and free sulfhydryl group content, and were analyzed using differential scanning calorimetry and Fourier transform infrared (FTIR) spectroscopy. Both processed and unprocessed eggs maintained superior quality when stored at 4 °C, as opposed to 25 °C. Pasteurization, regardless of method, led to superior maintenance of Haugh units during storage but also increased albumen opacity and decreased albumen overrun. Detrimental effects on quality markers were more severe in heat-pasteurized eggs than those treated with the ozone-based process. Pasteurization of shell eggs by either process did not affect lysozyme activity or sulfhydryl group content. Changes in protein secondary structure, as indicated by FTIR analysis, suggest that the ozone-based process is less damaging to albumen proteins than is the heat-alone process. In conclusion, heat-ozone pasteurization, by virtue of its less severe heat treatment, yields a safe final product that more closely resembles untreated shell eggs. © 2011 Institute of Food Technologists®

  10. 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.

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

    Science.gov (United States)

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

    2012-01-01

    Two physical experiments were developed to better define the thermal interaction of wetland water and the underlying soil layer. This information is important to numerical models of flow and heat transport that have been developed to support biological studies in the South Florida coastal wetland areas. The experimental apparatus consists of two 1.32. m diameter by 0.99. m tall, trailer-mounted, well-insulated tanks filled with soil and water. A peat-sand-soil mixture was used to represent the wetland soil, and artificial plants were used as a surrogate for emergent wetland vegetation based on size and density observed in the field. The tanks are instrumented with thermocouples to measure vertical and horizontal temperature variations and were placed in an outdoor environment subject to solar radiation, wind, and other factors affecting the heat transfer. Instruments also measure solar radiation, relative humidity, and wind speed.Tests indicate that heat transfer through the sides and bottoms of the tanks is negligible, so the experiments represent vertical heat transfer effects only. The temperature fluctuations measured in the vertical profile through the soil and water are used to calibrate a one-dimensional heat-transport model. The model was used to calculate the thermal conductivity of the soil. Additionally, the model was used to calculate the total heat stored in the soil. This information was then used in a lumped parameter model to calculate an effective depth of soil which provides the appropriate heat storage to be combined with the heat storage in the water column. An effective depth, in the model, of 5.1. cm of wetland soil represents the heat storage needed to match the data taken in the tank containing 55.9. cm of peat/sand/soil mix. The artificial low-density laboratory sawgrass reduced the solar energy absorbed by the 35.6. cm of water and 55.9. cm of soil at midday by less than 5%. The maximum heat transfer into the underlying peat-sand-soil mix

  12. SPECIFIC HEAT CAPACITY AND THERMAL CONDUCTIVITY OF HEAT STORAGE MATERIALS BASED ON PARAFFIN, BROWN-COAL WAX AND POLYETHYLENE WAX

    Directory of Open Access Journals (Sweden)

    Snezhkin Yu.

    2014-08-01

    Full Text Available The present paper overviews heat storage materials (HSM with phase change based on organic compounds. They consist of paraffin, brown-coal wax and polyethylene wax. These materials are produced on an industrial scale for the foundry work. It is shown that heat capacity of HSM in the solid and liquid states can be used for heat storage in addition to the heat of phase change. The results of investigations of phase change during heating and cooling HSM are presented. The studies are carried out by differential scanning calorimetry (DSC. The measurement techniques of the specific heat capacity and the coefficient of thermal conductivity are shown. Temperature dependences of the specific heat capacity of HSM in the solid and liquid states are researched by DSC. Values of the coefficient of thermal conductivity are determined by contact stationary technique of the flat plate over the entire temperature range of the operation of heat storage system.

  13. A genetic algorithm technique to optimize the configuration of heat storage in DH networks

    Directory of Open Access Journals (Sweden)

    Amru Rizal Razani

    2016-12-01

    Full Text Available The technical and economical evaluation of heat storage layout and configuration in the DH network is one of important aspect for optimizing the heat production from the heat supplier’s point of view in one side as well as to satisfy the heat customer demand in the other side. Generally, the state of the art technique has considered three optional planning layouts for DH network. A classical network with centralized heat storage at Combined Heat and Power (CHP plant, decentralized storages in the network, and decentralized small storages at the substations or in the customer building. In this paper, through the use of genetic algorithm technique, comparison of three different scenarios is presented to evaluate the optimal planning of heat storage layout in CHP based DH supply system according to economical and technical aspects in the network.

  14. ACR fuel storage analysis: finite element heat transfer analysis of dry storage

    Energy Technology Data Exchange (ETDEWEB)

    Khair, K.; Baset, S.; Millard, J. [Atomic Energy of Canada Limited, Mississauga, Ontario (Canada)

    2006-07-01

    Over the past decade Atomic Energy of Canada Limited (AECL) has designed and licensed air-cooled concrete structures used as above ground dry storage containers (MACSTOR) to store irradiated nuclear fuel from CANDU plants. A typical MACSTOR 200 module is designed to store 12,000 bundles in 20 storage cylinders. MACSTOR 200 modules are in operation at Gentilly-2 in Canada and at Cernavoda in Romania. The MACSTOR module is cooled passively by natural convection and by conduction through the concrete walls and roof. Currently AECL is designing the Advanced Candu Reactor (ACR) with CANFLEX slightly enriched uranium fuel to be used. AECL has initiated a study to explore the possibility of storing the irradiated nuclear fuel from ACR in MACSTOR modules. This included work to consider ways of minimizing footprint both in the spent fuel storage bay and in the dry storage area. The commercial finite element code ANSYS has been used in this study. The FE model is used to complete simulations with the higher heat source using the same concrete structural dimensions to assess the feasibility of using the MACSTOR design for storing the ACR irradiated fuel. This paper presents the results of the analysis. The results are used to confirm the possibility of using, with minimal changes to the design of the storage baskets and the structure, the proven design of the MACSTOR 200 containment to store the ACR fuel bundles with higher enrichment and burnup. This has thus allowed us to confirm conceptual feasibility and move on to investigation of optimization. (author)

  15. 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.

  16. Research of Operation Modes of Heat Storage Tank in CHP Plant Using Numerical Simulation

    National Research Council Canada - National Science Library

    Streckiene, Giedre; Miseviciute, Violeta

    2011-01-01

    ... ________________ _________________________________________________________________________________ Volume 6 Re search of Operation Modes of Heat Storage Tank in CHP Plant Using Numerical Simulation Giedre Streckiene 1 , Violeta Miseviciute 2 , 1 - 2 Department...

  17. A preliminary study on the heat storage fluxes of a tropical seasonal rain forest in Xishuangbanna

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    <正>In order to discuss the values and daily variation characteristics of heat storage fluxes in a tropical seasonal rain forest in Xishuangbanna, the sensible and latent heat storage flux within air column, canopy heat storage flux, energy storage by photosynthesis and ground heat storage above the soil heat flux plate, as well as the ratios of these heat storage fluxes to the net radiation in the cool-dry, hot-dry and rainy season were compared and analyzed based on the observation data of carbon fluxes, meteorological factors and biomass within this tropical seasonal rain forest from January 2003 to December 2004. The findings showed that heat storage terms ranged significantly in the daytime and weakly in the nighttime, and the absolute values of sensible and latent heat storage fluxes were obviously greater than other heat storage terms in all seasons. In addition, the absolute values of total heat storage fluxes reached the peak in the hot-dry season, then were higher in the rainy season, and reached the minimum in the cool-dry season. The ratios of heat storage fluxes to net radiation generally decreased with time in the daytime, moreover, the sensible and latent heat storage dominated a considerable fraction of net radiation, while other heat storage contents occupied a smaller fraction of the net radiation and the peak value was not above 3.5%. In the daytime, the ratios of the total heat storage to net radiation were greater and differences in these ratios were distinct among seasons before 12:00, and then they became lower and differences were small among seasons after 12:00. The energy closure was improved when the storage terms were considered in the energy balance, which indicated that heat storage terms should not been neglected. The energy closure of tropical seasonal rain forest was not very well due to effects of many factors. The results would help us to further understand energy transfer and mass exchange between tropical forest and atmosphere

  18. Non-equilibrium thermochemical heat storage in porous media

    DEFF Research Database (Denmark)

    Nagel, T.; Shao, H.; Singh, Ashok

    2013-01-01

    Thermochemical energy storage can play an important role in the establishment of a reliable renewable energy supply and can increase the efficiency of industrial processes. The application of directly permeated reactive beds leads to strongly coupled mass and heat transport processes that also...... compressible gas flow through a porous solid is presented along with its finite element implementation where solid-gas reactions occur and both phases have individual temperature fields. The model is embedded in the Theory of Porous Media and the derivation is based on the evaluation of the Clausius......-Duhem inequality. Special emphasis is placed on the interphase coupling via mass, momentum and energy interaction terms and their effects are partially illustrated using numerical examples. Novel features of the implementation of the described model are verified via comparisons to analytical solutions...

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

    Energy Technology Data Exchange (ETDEWEB)

    Regin, A. Felix; Solanki, S.C.; Saini, J.S. [Department of Mechanical and Industrial Engineering, Indian Institute of Technology Roorkee, Roorkee 247 667 (India)

    2008-12-15

    Thermal energy storage has recently attracted increasing interest related to thermal applications such as space and water heating, waste heat utilization, cooling and air-conditioning. Energy storage is essential whenever there is a mismatch between the supply and consumption of energy. Use of phase change material (PCM) capsules assembled as a packed bed is one of the important methods that has been proposed to achieve the objective of high storage density with higher efficiency. A proper designing of the thermal energy storage systems using PCMs requires quantitative information about heat transfer and phase change processes in PCM. This paper reviews the development of available latent heat thermal energy storage technologies. The different aspects of storage such as material, encapsulation, heat transfer, applications and new PCM technology innovation have been carried out. (author)

  20. Heat transfer in fuel oil storage tank at thermal power plants with local fuel heating

    Directory of Open Access Journals (Sweden)

    Kuznetsova Svetlana A.

    2015-01-01

    Full Text Available Results of mathematical modeling of the thermal control system in fuel oil storage, in the presence of heat source at the lower boundary of the region, in the framework of models of incompressible viscous fluid are presented. Solved the system of differential equations of non-stationary Navier-Stokes equations, the energy equation and the heat equation with appropriate initial and boundary conditions. Takes into account the processes of heat exchange region considered with the environment. A comparative analysis of the dependence of average temperatures of oil in the volume of the tank on the time calculated by the simplified (balanced method and obtained as a result of numerical simulation are performed.

  1. 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.

  2. Heat transfer enhancement in medium temperature thermal energy storage system using a multitube heat transfer array

    Energy Technology Data Exchange (ETDEWEB)

    Agyenim, Francis; Smyth, Mervyn [Centre for Sustainable Technologies, Ulster University, Newtownabbey BT37 0QB (United Kingdom); Eames, Philip [Electronic and Electrical Engineering, Loughborough University, Leicestershire LE11 3TU (United Kingdom)

    2010-01-15

    An experimental energy storage system has been designed using an horizontal shell and tube heat exchanger incorporating a medium temperature phase change material (PCM) with a melting point of 117.7 C. Two experimental configurations consisting of a control unit with one heat transfer tube and a multitube unit with four heat transfer tubes were studied. The thermal characteristics in the systems have been analysed using isothermal contour plots and temperature time curves. Temperature gradients along the three directions of the shell and tube systems; axial, radial and angular directions have been analysed and compared. The phase change in the multitube system was dominated by the effect of convective heat transfer compared to conductive heat transfer in the control system. The temperature gradient in the PCM during phase change was greatest in the radial direction for both the control and multitube systems. The temperature gradients recorded in the axial direction for the control and multitube systems during the change of phase were respectively 2.5 and 3.5% that of the radial direction, indicating essentially a two-dimensional heat transfer in the PCM. The onset of natural convection through the formation of multiple convective cells in the multitube system significantly altered the shape of the solid liquid interface fluid flow and indicates the requirement for an in-depth study of multitube arrangements. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Cabeza, L.F. [Universitat de Lleida (Spain). Escola Universitaria Politecnica; Mehling, H.; Hiebler, S.; Ziegler, F. [Bavarian Center for Applied Energy Research, Garching (Germany)

    2002-07-01

    Efficient and reliable storage systems for thermal energy are an important requirement in many applications where heat demand and supply or availability do not coincide. Heat and cold stores can basically be divided in two groups. In sensible heat stores the temperature of the storage material is increased significantly. Latent heat stores, on the contrary, use a storage material that undergoes a phase change (PCM) and a small temperature rise is sufficient to store heat or cold. The major advantages of the phase change stores are their large heat storage capacity and their isothermal behavior during the charging and discharging process. However, while unloading a latent heat storage, the solid-liquid interface moves away from the heat transfer surface and the heat flux decreases due to the increasing thermal resistance of the growing layer of the molten/solidified medium. This effect can be reduced using techniques to increase heat transfer. In this paper, three methods to enhance the heat transfer in a cold storage working with water/ice as PCM are compared: addition of stainless steel pieces, copper pieces (both have been proposed before) and a new PCM-graphite composite material. The PCM-graphite composite material showed an increase in heat flux bigger than with any of the other techniques. (Author)

  4. 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

  5. Building integration of photovoltaic systems in cold climates

    Science.gov (United States)

    Athienitis, Andreas K.; Candanedo, José A.

    2010-06-01

    This paper presents some of the research activities on building-integrated photovoltaic (BIPV) systems developed by the Solar and Daylighting Laboratory at Concordia University. BIPV systems offer considerable advantages as compared to stand-alone PV installations. For example, BIPV systems can play a role as essential components of the building envelope. BIPV systems operate as distributed power generators using the most widely available renewable source. Since BIPV systems do not require additional space, they are especially appropriate for urban environments. BIPV/Thermal (BIPV/T) systems may use exterior air to extract useful heat from the PV panels, cooling them and thereby improving their electric performance. The recovered thermal energy can then be used for space heating and domestic hot water (DHW) heating, supporting the utilization of BIVP/T as an appropriate technology for cold climates. BIPV and BIPV/T systems are the subject of several ongoing research and demonstration projects (in both residential and commercial buildings) led by Concordia University. The concept of integrated building design and operation is at the centre of these efforts: BIPV and BIPV/T systems must be treated as part of a comprehensive strategy taking into account energy conservation measures, passive solar design, efficient lighting and HVAC systems, and integration of other renewable energy systems (solar thermal, heat pumps, etc.). Concordia Solar Laboratory performs fundamental research on heat transfer and modeling of BIPV/T systems, numerical and experimental investigations on BIPV and BIPV/T in building energy systems and non-conventional applications (building-attached greenhouses), and the design and optimization of buildings and communities.

  6. Isobar gas and steam. Compressed air storage plant with heat storage; Isobares GuD. Druckluftspeicherkraftwrk mit Waermespeicher

    Energy Technology Data Exchange (ETDEWEB)

    Schlitzberger, Christian; Leithner, Reinhard; Nielsen, Lasse [Technische Univ. Braunschweig (Germany). Inst. fuer Waerme- und Brennstofftechnik

    2008-07-01

    Due to the worldwide increasing energy consumption the unfavourable aspects of the today's power supply structure are strengthened continuously. There are two compressed air energy storage power stations existing. However, these power stations exhibit worse efficiencies of storage in comparison to existing pumped-storage power plants. In order to avoid this disadvantage, a concept of a isobaric gas and steam compressed air storage plant was developed at the institute for heat and fuel technology at the technical university of Braunschweig. This concept is presented in the contribution under consideration.

  7. Thermochemical storage for ambient temperatures. Compact seasonal heat storage; Thermochemische opslag bij omgevingstemperatuur. Compacte seizoensopslag van warmte

    Energy Technology Data Exchange (ETDEWEB)

    Wemmers, A.K. [TNO Bouw en Ondergrond, Delft (Netherlands)

    2005-12-01

    The decoupling of demand and production of energy are important aspects in sustainable energy supply systems. Heat storage by commercially available techniques is realized for a temperature level higher than the ambient temperature. Heat loss is the result. By means of thermochemical storage heat can be stored more compact and on the level of ambient temperatures. [Dutch] De ontkoppeling van vraag en de opwekking van energie spelen een belangrijke rol bij de invulling van een duurzame energievoorziening. Opslag van warmte in huidige bekende technieken heeft plaats op een hoger temperatuurniveau dan de omgeving. Met warmteverlies tot gevolg. Met een nieuwe techniek, thermochemische opslag, kan compacter en op omgevingstemperatuurniveau worden opgeslagen.

  8. PCM Heat Storage Charged with a Double-Reflector Solar System

    Directory of Open Access Journals (Sweden)

    Amos Veremachi

    2016-01-01

    Full Text Available A “Solar Salt” (NaNO3–KNO3 60 : 40 molar mixture latent heat storage has been charged by direct solar illumination. Solar Salt as a Phase Change Material (PCM can be an attractive small scale heat storage solution, as the melting temperature of about 220°C can be suitable for cooking purposes. The tests were made with a double-reflector setup. In this setup a secondary reflector positioned above the focal point of the primary reflector directs the rays onto a heat storage positioned below a hole in the primary reflector. The reflectors are tracking the sun, but the storage is stationary. The direct illumination of the absorber top plate during the tracking of the sun melted the salt in the storage through conducting fins. This is a system where portable heat batteries can be charged, during sunshine hours, and then provide heat for cooking during evening times.

  9. Experimental analysis of a solar assisted absorption heat pump with earth seasonal storage

    Energy Technology Data Exchange (ETDEWEB)

    Lazzarin, R.M.

    A plant composed of an energy roof, a seasonal earth storage and an absorption heat pump has been tested. The purpose was to study the behaviour of the various components and their interaction. The surveys were carried out over a two year period. The following operations were considered: the charging of the earth storage by the energy roof and the working of an absorption heat pump connected either to the energy roof or to the earth storage.

  10. Optimization of a thermal storage unit combined with a biomass bioler for heating buildings

    OpenAIRE

    Butala, Vincenc; Stritih, Uroš

    2015-01-01

    The performance of a boiler with a built-in thermal storage unit is presented.The thermal storage unit is an insulated water tank that absorbs surplus heat from the boiler. The stored heat in the thermal storage unit makes it possible to heat even when the boiler is not operating, thus increasing the heating efficiency. A system with three components is described. The model of the system and the mathematical model were made using the TRNSYS program package and a test reference year (TRY). The...

  11. Performance of underground heat storage system in a double-film-covered greenhouse

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    An underground heat storage system in a double-film-covered greenhouse and an adjacent greenhouse without the heat storage system were designed on the basis of plant physiology to reduce the energy consumption in greenhouses. The results indicated that the floor temperature was respectively 5.2 ℃, 4.6 ℃ and 2.0℃ higher than that of the soil in the adjacent reference greenhouse after heat storage in a clear, cloudy and overcast sky in winter. Results showed that the temperature and humidity were feasible for plant growth in the heat saving greenhouse.

  12. Study on performance of a packed bed latent heat thermal energy storage unit integrated with solar water heating system

    Institute of Scientific and Technical Information of China (English)

    NALLUSAMY N.; SAMPATH S.; VELRAJ R.

    2006-01-01

    In thermal systems such as solar thermal and waste heat recovery systems, the available energy supply does not usually coincide in time with the process demand. Hence some form of thermal energy storage (TES) is necessary for the most effective utilization of the energy source. This study deals with the experimental evaluation of thermal performance of a packed bed latent heat TES unit integrated with solar flat plate collector. The TES unit contains paraffin as phase change material (PCM) filled in spherical capsules, which are packed in an insulated cylindrical storage tank. The water used as heat transfer fluid (HTF) to transfer heat from the solar collector to the storage tank also acts as sensible heat storage material. Charging experiments were carried out at varying inlet fluid temperatures to examine the effects of porosity and HTF flow rate on the storage unit performance. The performance parameters such as instantaneous heat stored, cumulative heat stored, charging rate and system efficiency are studied.Discharging experiments were carried out by both continuous and batchwise processes to recover the stored heat, and the results are presented.

  13. 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).

  14. Numerical Investigation of Effective Heat Conductivity of Fluid in Charging Process of Thermal Storage Tank

    OpenAIRE

    Taheri, H.; Schmidt, F. P.; Gabi, M.

    2015-01-01

    This paper presents a numerical case study of heat transfer mechanisms during the charging process of a stratified thermal storage tank applied in a specific adsorption heat pump cycle. The effective thermal conductivity of the heat transfer fluid during the charging process is analyzed through CFD simulations using Unsteady Reynolds-averaged Navier-Stokes equations (URANS). The aim of the study is to provide an equivalent thermal conductivity for a one-dimensional storage tank model to be us...

  15. Combined solar heat and power system with a latent heat storage - system simulations for an economic assessment

    Science.gov (United States)

    Zipf, Verena; Neuhäuser, Anton

    2016-05-01

    Decentralized solar combined heat and power (CHP) systems can be economically feasible, especially when they have a thermal storage. In such systems, heat provided by solar thermal collectors is used to generate electricity and useful heat for e.g. industrial processes. For the supply of energy in times without solar irradiation, a thermal storage can be integrated. In this work, the performance of a solar CHP system using an active latent heat storage with a screw heat exchanger is investigated. Annual yield calculations are conducted in order to calculate annual energy gains and, based on them; economic assumptions are used to calculated economic numbers in order to assess the system performance. The energy savings of a solar system, compared to a system with a fossil fuel supply, are calculated. Then the net present value and the dynamic payback are calculated with these savings, the initial investment costs and the operational costs. By interpretation and comparison of these economic numbers, an optimum system design in terms of solar field size and storage size was determined. It has been shown that the utilization of such systems can be economical in remote areas without gas and grid connection. Optimal storage design parameters in terms of the temperature differences in the heat exchanger and the storage capacity have been determined which can further increase the net present value of such system.

  16. 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.

  17. Experimental testing of various heat transfer structures in a flat plate thermal energy storage unit

    Science.gov (United States)

    Johnson, Maike; Fiß, Michael; Klemm, Torsten

    2016-05-01

    For solar process heat applications with steam as the working fluid and varying application parameters, a novel latent heat storage concept has been developed using an adaptation of a flat plate heat exchanger as the storage concept. Since the pressure level in these applications usually does not exceed 30 bar, an adaptation with storage material chambers arranged between heat transfer medium chambers is possible. Phase change materials are used as the storage medium, so that the isothermal evaporation of steam during discharging of the storage is paired with the isothermal solidification of the storage material. Heat transfer structures can be inserted into the chambers to adjust the power level for a given application. By combining the required number of flat plate heat exchanger compartments and inserting the appropriate heat transfer structure, the design can easily be adjusted for the required power level and capacity for a specific application. Within this work, the technical feasibility of this concept is proven. The dependence of the operating characteristics on the geometry of the heat exchanger is identified. A focus is on varying the power density by integrating conductive heat structures in the PCM.

  18. 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

  19. 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 a 100 mm thick concrete slab was found to increase with increasing heat transfer coefficients as high as 30 W/m2K. In contrast the heat storage capacity of a thin gypsum plaster board was found to be constant when the heat transfer coefficient exceeded 3 W/m2K. Additionally, the optimal thickness...... potential. However, because heat gains and night ventilation periods do not coincide in time, a sufficient amount of thermal mass is needed in the building to store the heat. Assuming a 24 h-period harmonic oscillation of the indoor air temperature within a range of thermal comfort, the analytical solution...

  20. 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.

  1. 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 existin...

  2. 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.

  3. Study on cascade type underground thermal storage solar heating system in Tehran

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Yasutaka; Kaabi-Nejadian, A.; Ito, Sachio

    1986-12-01

    The conventional thermonuclear long-term underground thermal storage solar heating system packed with latent heat storage material in Tehran was improved by preventing the cascade operations of the heat pump units and direct heating hot-air fans from interfering each other and by enhancing the heat recovery rate from the soil. The improved system was simulated. The results obtained in Tehran were compared with those obtained in Tokyo. The collecting efficiency and the heat recovery rate significantly depend upon the surface area of collector and the operating time of heat pumps, respectively, in Tehran. The relationship of the surface area of collector with the heat recovery rate shows the same trend and the heat recovery rate from the soil increases with increasing of the operating time of heat pump in both Tehran and Tokyo. The interference of the heat pumps and direct heating hotair fans is prevented and especially the operation of heat pump is effective for effectively using the thermal characteristics of the storage and dissipation of heat in the soil. (3 refs, 4 figs, 10 tabs)

  4. Cooling Performance Evaluation of the Hybrid Heat Pipe for Spent Nuclear Fuel Dry Storage Cask

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Yeong Shin; Bang, In Cheol [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-10-15

    To evaluate the concept of the cooling device, 2-step CFD analysis was conducted for the cooling performance of hybrid heat pipe, which consists of single fuel assembly model and full scope dry cask model. As a passive cooling device of the metal cask for dry storage of spent nuclear fuel, hybrid heat pipe was applied to DPC developed in Korea. Hybrid heat pipe is the heat pipe containing neutron absorber can be used as a passive cooling in nuclear application with both decay heat removal and control the reactivity. In this study, 2-step CFD analysis was performed to find to evaluate the heat pipe-based passive cooling system for the application to the dry cask. Only spent fuel pool cannot satisfy the demands for high burnup fuel and large amount of spent fuel. Therefore, it is necessary to prepare supplement of the storage facilities. As one of the candidate of another type of storage, dry storage method have been preferred due to its good expansibility of storage capacity and easy long-term management. Dry storage uses the gas or air as coolant with passive cooling and neutron shielding materials was used instead of water in wet storage system. It is relatively safe and emits little radioactive waste for the storage. As short term actions for the limited storage capacity of spent fuel pool, it is considered to use dry interim/long term storage method to increase the capacity of spent nuclear fuel storage facilities. For 10-year cooled down spent fuel in the pool storage, fuel rod temperature inside metal cask is expected over 250 .deg. C in simulation. Although it satisfied the criteria that cladding temperature of the spent fuel should keep under 400 .deg. C during storage period, high temperature inside cask can accelerate the thermal degradation of the structural materials consisting metal cask and fuel assembly as well as limitation of the storage capacity of metal cask. In this paper, heat pipe-based cooling device for the dry storage cask was suggested for

  5. Heat and cold storage with PCM. An up to date introduction into basics and applications

    Energy Technology Data Exchange (ETDEWEB)

    Mehling, Harald [Bayerisches Zentrum fuer Angewandte Energieforschung e.V. (ZAE Bayern), Garching (Germany). Abt. Energieumwandlung und Speicherung; Cabeza, Luisa F. [Lleida Univ. (Spain). Dept. d' Informatica i Enginyeria Industrial

    2008-07-01

    Latent heat storage with phase change materials (PCM) has the potential to improve significantly the efficiency of heat and cold storages and to reduce their size considerably. The book is an introduction into the field for researchers and students. It summarizes and explains the basics, general concepts, and applications with examples in a single text. For a better understanding, many derivations, graphs and tables are included. All aspects from materials analysis and modification, storage design, storage integration, and different application examples are covered. Special focus is on applications in buildings. (orig.)

  6. Study on thermal performance of semi-transparent building-integrated photovoltaic glazings

    Energy Technology Data Exchange (ETDEWEB)

    Fung, Tady Y.Y.; Yang, H. [Renewable Energy Research Group, Department of Building Services Engineering, The Hong Kong Polytechnic University, Hung Hom (China)

    2008-07-01

    This paper presents a one-dimensional transient heat transfer model, the Semi-transparent Photovoltaic module Heat Gain (SPVHG) model, for evaluating the heat gain of semi-transparent photovoltaic modules for building-integrated applications. The energy that is transmitted, absorbed and reflected in each element of the building-integrated photovoltaic (BIPV) modules such as solar cells and glass layers were considered in detail in the SPVHG model. Solar radiation model for inclined surface has been incorporated into the SPVHG model. The model is applicable to photovoltaic (PV) modules that have different orientations and inclinations. The annual total heat gain was evaluated by using the SPVHG model. The impacts of different parameters of the PV module were investigated. It was found that solar heat gain is the major component of the total heat gain. The area of solar cell in the PV module has significant effect on the total heat gain. However, the solar cell energy efficiency and the PV module's thickness have only a little influence on the total heat gain. The model was also validated by laboratory tests by using a calorimeter box apparatus and an adjustable solar simulator. The test results showed that the simulation model predicts the actual situation well. (author)

  7. Computer simulation of ground coupled storage in a series solar assisted heat pump system

    Energy Technology Data Exchange (ETDEWEB)

    Andrews, John W.; Metz, Philip D.

    1979-01-01

    A quantitative study of the effect of thermal coupling between the ground and the heat storage element of a series solar assisted heat pump system is presented. The transient simulation computer program TRNSYS is used to simulate the solar portion of this system. A program to simulate the thermal interaction of the storage element with the ground is incorporated into TRNSYS as a sub-routine. This program calculates heat flow through the ground in discrete steps over space and time. Boundary conditions are established. The ground coupled storage is driven by thermal inputs from the solar portion of the system and from the changing ambient and ground temperatures.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kim, In Young; Lee, Un Chul [Seoul National University, Seoul (Korea, Republic of)

    2011-12-15

    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.

  9. Heat storage rate and acute fatigue in rats

    Directory of Open Access Journals (Sweden)

    L.O.C. Rodrigues

    2003-01-01

    Full Text Available Thermal environmental stress can anticipate acute fatigue during exercise at a fixed intensity (%VO2max. Controversy exists about whether this anticipation is caused by the absolute internal temperature (Tint, ºC, by the heat storage rate (HSR, cal/min or by both mechanisms. The aim of the present study was to study acute fatigue (total exercise time, TET during thermal stress by determining Tint and HSR from abdominal temperature. Thermal environmental stress was controlled in an environmental chamber and determined as wet bulb globe temperature (ºC, with three environmental temperatures being studied: cold (18ºC, thermoneutral (23.1ºC or hot (29.4ºC. Six untrained male Wistar rats weighing 260-360 g were used. The animals were submitted to exercise at the same time of day in the three environments and at two treadmill velocities (21 and 24 m/min until exhaustion. After implantation of a temperature sensor and treadmill adaptation, the animals were submitted to a Latin square experimental design using a 2 x 3 factorial scheme (velocity and environment, with the level of significance set at P<0.05. The results showed that the higher the velocity and the ambient temperature, the lower was the TET, with these two factors being independent. This result indicated that fatigue was independently affected by both the increase in exercise intensity and the thermal environmental stress. Fatigue developed at different Tint and HSR showed the best inverse relationship with TET. We conclude that HSR was the main anticipating factor of fatigue.

  10. An experimental study of enhanced heat transfer in rectangular PCM thermal storage

    Energy Technology Data Exchange (ETDEWEB)

    Stritih, U. [University of Ljubljana (Slovenia). Faculty of Mechanical Engineering

    2004-06-01

    The heat-transfer characteristics of a latent-heat storage unit with a finned surface have been experimentally studied in terms of the solidification and melting processes by comparing them with those of a heat-storage unit with a plain surface. Paraffin with a melting point of 30{sup o}C was used in the investigations because it is appropriate for thermal storage applications in buildings. Time-based variations of the temperature distributions and heat flux are explained from the results of observations of the melting and the solidification layers. The dimensionless Nusselt number was calculated as a function of the Rayleigh number for natural convection in the paraffin for both the melting and the solidification processes. The effectiveness of the fins was calculated from the quotient of the heat flux with fins and the heat flux without fins. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Gu, Lianhong [ORNL; Meyers, T. P. [NOAA ATDD; Pallardy, Stephen G. [University of Missouri; Hanson, Paul J [ORNL; Yang, Bai [ORNL; Heuer, Mark [ATDD, NOAA; Hosman, K. P. [University of Missouri; Liu, Qing [ORNL; Riggs, Jeffery S [ORNL; Sluss, Daniel Wayne [ORNL; Wullschleger, Stan D [ORNL

    2007-01-01

    We conducted observations and modeling at a forest site to assess importance of biomass heat and biochemical energy storages for land-atmosphere interactions. We used the terrestrial ecosystem Fluxes And Pools Integrated Simulator (FAPIS). We first examined FAPIS performance by testing its predictions with and without biomass energy storages against measurements of surface energy and CO2 fluxes. We then evaluated the magnitudes and temporal patterns of the calculated biomass energy storages. Effects of energy storages on flux exchanges and variations of radiative temperature were investigated by contrasting FAPIS simulations with and without the storages. We found that with the storages, FAPIS predictions agreed with measurements well; without them, FAPIS performance deteriorated for all surface energy fluxes. The biomass heat storage and biochemical energy storage had clear diurnal patterns with typical ranges from -50 to 50 and -3 to 20 Wm-2, respectively; these typical ranges were exceeded substantially when there were sudden changes in atmospheric conditions. Without-storage simulations produced larger sensible and latent heat fluxes during the day but smaller fluxes (more negative values) at night as compared with with-storage simulations. Similarly, without-storage simulations had higher surface radiative temperature during the day but lower radiative temperature at night, indicating that the biomass energy storages act to dampen diurnal temperature range. Therefore, biomass heat and biochemical energy storages are an integral and substantial part of the surface energy budget and play a role in modulating land surface temperatures and must be considered in studies of land - atmosphere interactions and climate modeling.

  12. 蓄热式电热蒸汽锅炉%Heat storage type electric steam boilers

    Institute of Scientific and Technical Information of China (English)

    庄正宁; 唐桂华; 叶永强

    2001-01-01

    介绍了蓄热式电热蒸汽锅炉供热系统的供热原理、装置配置和设计要点,该供热系统具有广阔的应用前景。%The heat supply principle, unit arrangement, and desigh factor of the heat supply system of the heat storage type electric steam boilers were presented, the heat supply system could be widely applied.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  14. 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.

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

    Directory of Open Access Journals (Sweden)

    A. Lindroth

    2009-08-01

    Full Text Available 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

  16. 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 t

  17. 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.

  18. Experimental investigation on the thermal performance of heat storage walls coupled with active solar systems

    Science.gov (United States)

    Zhao, Chunyu; You, Shijun; Zhu, Chunying; Yu, Wei

    2016-12-01

    This paper presents an experimental investigation of the performance of a system combining a low-temperature water wall radiant heating system and phase change energy storage technology with an active solar system. This system uses a thermal storage wall that is designed with multilayer thermal storage plates. The heat storage material is expanded graphite that absorbs a mixture of capric acid and lauric acid. An experiment is performed to study the actual effect. The following are studied under winter conditions: (1) the temperature of the radiation wall surface, (2) the melting status of the thermal storage material in the internal plate, (3) the density of the heat flux, and (4) the temperature distribution of the indoor space. The results reveal that the room temperature is controlled between 16 and 20 °C, and the thermal storage wall meets the heating and temperature requirements. The following are also studied under summer conditions: (1) the internal relationship between the indoor temperature distribution and the heat transfer within the regenerative plates during the day and (2) the relationship between the outlet air temperature and inlet air temperature in the thermal storage wall in cooling mode at night. The results indicate that the indoor temperature is approximately 27 °C, which satisfies the summer air-conditioning requirements.

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

    DEFF Research Database (Denmark)

    Schultz, Jørgen Munthe; Furbo, Simon

    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...

  20. Seasonal heat storage in underground caverns. Final report; Saisonale Waermespeicherung in Grubenraeumen. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Eikmeier, B.; Mohr, M.; Unger, H.

    1999-11-01

    The solar assisted heat supply of buildings can provide an important contribution in order to achieve the targets of minimization of primary energy consumption and reduction of greenhouse gas emissions. However, the problem of the seasonal divergence between the high solar energy supply in the summer and the high demand in the winter consists; therefore seasonal heat storage is indispensable. Here, a considerable fraction of the investments must be addressed to the central reservoir. An approach towards the reduction of the investment costs for the installation of seasonal storages in the use of cavities, which are already available in mines. In the Ruhr-Area a complex net of subterranean cavities is available. For the cost estimation of solar assisted heat supply with integrated storage in mines, the reference suburban colony 'Essen-Stoppenberg' with 42 double family houses is chosen. The specific storage costs are estimated for different technical options (tunnel- or shaft storage, direct or indirect charging system). In most cases these costs are comparable to other seasonal heat storage projects. With advantageous conditions specific capital expenditures can be achieved, which are lower than those of conventional seasonal storage. However, it must be considered, that the operating costs of pit storages are expected to be higher. (orig.)

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

    NARCIS (Netherlands)

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

    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

  2. Modelling the Size of Seasonal Thermal Storage in the Solar District Heating System

    Directory of Open Access Journals (Sweden)

    Giedrė Streckienė

    2012-12-01

    Full Text Available The integration of a thermal storage system into the solar heating system enables to increase the use of solar thermal energy in buildings and allows avoiding the mismatch between consumers’ demand and heat production in time. The paper presents modelling a seasonal thermal storage tank various sizes of which have been analyzed in the district solar heating system that could cover a part of heat demand for the district of individual houses in Vilnius. A biomass boiler house, as an additional heat source, should allow covering the remaining heat demand. energyPRO software is used for system modelling. The paper evaluates heat demand, climate conditions and technical characteristics.Article in Lithuanian

  3. 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...... Central Solar Heating Plants, servicing District Heating and related developments in large-scale thermal storage. Central solar heating today is a mature and economic realistic solution for district heating based on a renewable source. The cost for solar collectors has decreased by nearly ¼ during...... 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...

  4. Heat storage characteristics of latent microcapsules using hot air bubbles by direct contact heat exchange; Onshitsu kihogun to sennetsu microcapsule tono chokusetsu sesshohku kokan ni yoru chikunetsu tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Nakagawa, K.; Sugiura, T. [Toyohashi University of Technology, Aichi (Japan)

    2000-05-25

    This paper has dealt with the heat storage characteristics of fine microcapsules packed with latent heat storage material in the water layer. The heat storage operation to the latent microcapsules was carried out using hot air bubbles by direct contact heat exchange. The microcapsule consists of n-paraffin as a core latent-heat storage material and melamine resin as a coating substance. The relation of the completion time of latent-heat storage to some parameters was examined experimentally. The non-dimensional correlation equations for the completion time of latent-heat storage process had were derived in terms of the ratio of water layer height to diameter of microcapsule, Reynolds number for air flow, Stefan number and modified Stefan number for absolute humidity of flowing air. (author)

  5. 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.

  6. Barents Sea heat – transport, storage and surface fluxes

    Directory of Open Access Journals (Sweden)

    Ø. Skagseth

    2009-07-01

    Full Text Available Sensitivity of the Barents Sea to variation in ocean heat transport and surface fluxes is explored using a 1-D column model. Mean monthly ocean transport and atmospheric forcing are synthesised and force model results that reproduce the observed winter convection and surface warming and freshening well. Model results are compared to existing estimates of the ocean to air heat fluxes and horizontally averaged profiles for the southern and northern Barents Sea. 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, the major part of the area, 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 in the north, the balance is achieved by long wave loss removing most of the solar heating, and the model also suggests a positive sensible heat gain. During the last decade the Barents Sea has experienced an atmospheric warming and an increased ocean heat transport. Despite large changes the Barents Sea heat loss remains robust, the temperature adjusts, and the yearly cycle remains. 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 probably leads to a spreading of warm water further north.

  7. Waste heat recovery from diesel engine using custom designed heat exchanger and thermal storage system with nanoenhanced phase change material

    Directory of Open Access Journals (Sweden)

    Wilson John Maria Robert

    2017-01-01

    Full Text Available In this research study an attempt has been made to recover the heat energy of the exhaust gas from a Diesel engine, using a triangular finned shell and tube heat exchanger with segmental baffle at 20°, and efficiently store as sensible and latent heat energy using thermal storage tank having phase change material with CuO nanoparticles. The nanoparticles and the phase change material form the nanoparticle-enhanced phase change material and mainly the thermal conductivity of the phase change material can be enhanced through the dispersion of the nanoparticles. The temperature variations of the heat transfer fluid in the heat recovery heat exchanger with various load conditions of the Diesel engine are studied. The performance of the heat exchanger is evaluated using heat extraction rate and effectiveness. Evaluation of the performance of the thermal storage system can be analyzed by using the total heat energy stored and charging rate during the charging period for the selected nanoparticle-enhanced phase change material.

  8. Toyota's heat management system - coolant heat storage for mass production today, new technologies for the future

    Energy Technology Data Exchange (ETDEWEB)

    Ichinose, Hiroki; Takaoka, Toshifumi; Kobayashi, Hideo [Toyota Motor Corporation (Japan)

    2004-07-01

    There has been pressing needs for the protection of metropolitan environment and the challenge of global warming. A heat management system prevails to meet such requirements. In actual driving condition, only about 30% of the total fuel energy is consumed for propulsion and air conditioner. At the same time 60% of fuel energy is wasted as exhaust gas, thermal loss and warm up loss. It is important to manage total thermal energy as a whole vehicle to improve thermal efficiency. The principle is to reduce heat loss in order to increase exhaust gas temperature and recover heat energy for pre-heating at the next cold start. Further developed versions may include thermal management strategies including turbocharger and thermal exchanger using exhaust gas heat energy. Toyota has developed the Coolant Heat Storage system (CHSS) for one of heat management systems to reduce cold emission and improve cabin comfort. The system enables to store hot coolant at the warmed up condition in a heat storage tank. At the next cold start, it is possible for CHSS to reduce unburned hydrocarbon by preheating intake port quickly with the hot coolant in the tank. CHSS was adopted in hybrid vehicle Prius for the US model in 2003. This vehicle achieved to meet the ATPZEV,the most stringent emission regulation in the US. This paper describes a total heat management focusing on the newly developed CHSS.

  9. 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...

  10. Energy analysis of heat surplus storage systems in plastic tunnels

    Energy Technology Data Exchange (ETDEWEB)

    Kurpaska, S.; Latala, H. [Institute of Agricultural Engineering and Computer Science, University of Agriculture in Krakow, Balicka 116 B, Krakow 30-149 (Poland)

    2010-12-15

    This paper presents the findings of a theoretical analysis and experimental verification on the storing of heat excess in soil and liquid accumulators located in a foil tunnel. There was positive verification of the formulated macroscopic heat exchange model in both accumulators (maximum error 81%) and the quantity of heat stored in them was defined. During the experiments, under existing weather conditions, the amount of stored heat stood between 6 MJ and 45 MJ in the liquid accumulator and between 9 MJ and 130 MJ in the soil accumulator. The quantity of heat supplied from the accumulator to the interior of the tunnel during discharging, which stood between 0.6 MJ and 46 MJ, was also described. The COP was determined for the tested system both for the accumulator charging process and the discharging of the soil accumulator. Furthermore, the quantity of heat used for heating up heat originating from the discharging of the accumulator whilst heating the tunnel for favourable and unfavourable surrounding climate conditions was determined. (author)

  11. Regeneration and efficiency characterization of hybrid adsorbent for thermal energy storage of excess and solar heat

    Energy Technology Data Exchange (ETDEWEB)

    Dicaire, Daniel; Tezel, F. Handan [University of Ottawa, Department of Chemical and Biological Engineering, 161 Louis Pasteur, Colonel By Hall, A402, Ottawa, ON, K1N 6N5 (Canada)

    2011-03-15

    Adsorption Thermal Energy Storage (TES) is a promising technology for long term thermal energy storage of excess and solar heat. By using the exothermic reversible adsorption process, excess heat from an incinerator or solar heat from the summer can be stored and then released for heating during the winter. The usefulness of the storage system relies heavily on the temperature and quality of the heat available for regeneration of the adsorbent as it affects the storage efficiency, the amount of water released from the adsorbent and in turn the performance or energy density of the storage system. In this study, a lab scale high throughput open loop forced air adsorption TES has been built. A series of adsorption experiments were performed to determine the effect of adsorption flow rate and cycling on the chosen best performing adsorbent, AA13X from Rio Tinto Alcan. Regeneration characterization experiments were performed to determine the effect of flow rate, temperature and feed air relative humidity on the regeneration and performance of the system. The results were compared with another adsorbent to verify the observed trend. Finally, the efficiency of the thermal storage system was calculated. (author)

  12. 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...

  13. Numerical Analysis of Doublet Wells for Cold Energy Storage on Heat Damage Treatment in Deep Mines

    Institute of Scientific and Technical Information of China (English)

    HE Man-chao; ZHANG Yi; GUO Dong-ming; QIAN Zeng-zhen

    2006-01-01

    Deep mining is an inevitable tendency in the development of coal industry. There are many heat damage problems with the increase of mining depth. The technology of using doublet wells, together with Heat Exchange Machine Systems (HEMSs), to store cold energy is a key to solve the heat damage problems in deep mines. Based on the geological conditions, thermodynamic and hydraulic parameters of Jiahe Mine, the isotherms in the period of cold energy storage and refrigeration and the volumes of cold water within different temperature ranges of the cold energy storage well were numerically analyzed. The results show that 1) with the same pumped and injected water volumes, the lower the temperature of injected water is, the larger the volume of cold water in the cold energy storage well is. With the larger volume, the effect of cold energy storage is better. 2) the larger the volumes of pumped and reinjected water are, the larger the volume of cold water from the cold energy storage well is. With the larger volume, the effect of refrigeration is better. And 3) without disturbance, the volume and temperature of cold water in the cold energy storage well can keep unchanged or have only a little change for a long time. Therefore the technology of doublet wells for cold energy storage is feasible and the cold energy storage aquifers can meet the requirement of the technology.

  14. Thermal energy storage – overview and specific insight into nitrate salts for sensible and latent heat storage

    Directory of Open Access Journals (Sweden)

    Nicole Pfleger

    2015-07-01

    Full Text Available Thermal energy storage (TES is capable to reduce the demand of conventional energy sources for two reasons: First, they prevent the mismatch between the energy supply and the power demand when generating electricity from renewable energy sources. Second, utilization of waste heat in industrial processes by thermal energy storage reduces the final energy consumption. This review focuses mainly on material aspects of alkali nitrate salts. They include thermal properties, thermal decomposition processes as well as a new method to develop optimized salt systems.

  15. Laboratory Test of a Cylindrical Heat Storage Module with Water and Sodium Acetate Trihydrate

    DEFF Research Database (Denmark)

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

    2016-01-01

    Cylindrical heat storage modules with internal heat exchangers have been tested in a laboratory. The modules were filled with water and sodium acetate trihydrate with additives. The testing focused on the heat content of the storage material and the heat exchange capacity rate during charge...... of the module. For the tests with the phase change materials, the focus was furthermore on the stability of supercooling and cycling stability. Testing the module with sodium acetate trihydrate and 6.4% extra water showed that phase separation increased and the heat released after solidification of supercooled...... phase change material was reduced over 17 test cycles. The heat released after solidification of the supercooled sodium acetate trihydrate with thickening agent and graphite was stable over the test cycles. Stable supercooling was obtained in 7 out of 17 test cycles with the module with sodium acetate...

  16. Numerical and experimental study on heat pump water heater with PCM for thermal storage

    Energy Technology Data Exchange (ETDEWEB)

    Long, Jian-You; Zhu, Dong-Sheng [Key Laboratory of Enhanced Heat Transfer and Energy Conservation of the Ministry of Education, Academy of Chemistry and Energy, South China University of Technology, Guangzhou, Guangdong 510640 (China)

    2008-07-01

    An air source heat pump water heater with phase change material (PCM) for thermal storage was designed to take advantage of off-peak electrical energy. The heat transfer model of PCM was based upon a pure conduction formulation. Quasi-steady state method was used to calculate the temperature distribution and phase front location of PCM during thermal storage process. Temperature and thermal resistance iteration approach has been developed for the analysis of temperature variation of heat transfer fluid (HTF) and phase front location of PCM during thermal release process. To test the physical validity of the calculational results, experimental studies about storing heat and releasing heat of PCM were carried. Comparison between the calculational results and the experimental data shows good agreement. Graphical results including system pressure and input power of heat pump, time-wise variation of stored and released thermal energy of PCM were presented and discussed. (author)

  17. 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.

  18. 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.

  19. The Development of Small Solar Concentrating Systems with Heat Storage for Rural Food Preparation

    Science.gov (United States)

    van den Heetkamp, R. R. J.

    A system, consisting of a parabolic reflector mounted on a polar axis tracker, has been designed and built. Air at atmospheric pressure is heated by the concentrated solar radiation to temperatures of up to 400°C as it is sucked through the receiver and into the pebble-bed heat storage unit, by means of a fan at the bottom of the storage. The stored heat is recovered by the reversal of the fan and the resulting hot air can be used in a convection oven and other appliances. This report discusses practical aspects, as well as preliminary test results, of such a system.

  20. 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.

  1. Why and Organic Heat Transfer Medium Remains today a Good Option for Thermal Storage and Transfer of Heat?

    Energy Technology Data Exchange (ETDEWEB)

    Guillaume, C. A.

    2006-07-01

    With Therminol(reg. sign) heat transfer division we were from the early days when few solar projects over the world. Therminol(reg. sign) VP-1 or 55 flows in mirrors field to collect the heat in the most economical and safest way. This heat transfer medium able to work between temperatures up to 400{sup o}C . The selection of the fluid was made after many testing of properties under heat stresses over the long life of the plants. Other parameters were also evaluated such as the storage heat capacity and the transfer ability of the heat energy into to a steam generator. Over the years of fluid monitoring for its performances a cumulative experience was grasped from fluids have been used to develop new products aiming to improve the impact in the environment of other product like molten salts. Recent investigations are responding to the safety requirement for new plants construction and European standards. (Author)

  2. Pulse mitigation and heat transfer enhancement techniques. Volume 4: Transient behavior of heat pipe with thermal energy storage under pulse heat loads

    Science.gov (United States)

    Chow, L. C.; Chang, M. J.

    1992-08-01

    A novel design of a high-temperature axially grooved heat pipe (HP), which utilizes thermal energy storage (TES) to mitigate pulse heat loads, was presented. Phase-change material (PCM) encapsulated in cylindrical containers was used for thermal energy storage. The transient responses of the HP/TES system under two types of pulse heat loads were studied numerically. The first type is pulse heat loads applied at the heat pipe evaporator; the second type is reversed-pulse heat loads applied at the condenser. The transient response of three different HP/TES configurations were compared: (1) a heat pipe with a large empty cylinder installed in the vapor core, (2) a heat pipe with a large PCM cylinder, and (3) a heat pipe with six small PCM cylinders. It was found that the PCM is very effective in mitigating the adverse effect of pulse heat loads. The six small PCM cylinders are more efficient than the large PCM cylinder in relaxing the heat pipe temperature increase under pulse heat loads.

  3. Thermal performance of PCM thermal storage unit for a roof integrated solar heating system

    Energy Technology Data Exchange (ETDEWEB)

    Saman, W.; Bruno, F.; Halawa, E. [South Australia Univ., Sustainable Energy Centre, Adelaide, SA (Australia)

    2005-02-01

    The thermal performance of a phase change thermal storage unit is analysed and discussed. The storage unit is a component of a roof integrated solar heating system being developed for space heating of a home. The unit consists of several layers of phase change material (PCM) slabs with a melting temperature of 29 deg C. Warm air delivered by a roof integrated collector is passed through the spaces between the PCM layers to charge the storage unit. The stored heat is utilised to heat ambient air before being admitted to a living space. The study is based on both experimental results and a theoretical two dimensional mathematical model of the PCM employed to analyse the transient thermal behaviour of the storage unit during the charge and discharge periods. The analysis takes into account the effects of sensible heat which exists when the initial temperature of the PCM is well below or above the melting point during melting or freezing. The significance of natural convection occurring inside the PCM on the heat transfer rate during melting which was previously suspected as the cause of faster melting process in one of the experiments is discussed. The results are compared with a previous analysis based on a one dimensional model which neglected the effect of sensible heat. A comparison with experimental results for a specific geometry is also made. (Author)

  4. Power of design - the future of building-integrated PV

    Energy Technology Data Exchange (ETDEWEB)

    Abbate, Cinzia [ENEL, Rome (Italy). Officine di Architettura

    2001-04-01

    This paper discusses strategies to make building integrated photovoltaic (PV) systems more acceptable and to allow PV material to compete with conventional construction material. The history of developments in building integration and difficulties encountered by architects wishing to use PV products are explored, and the Dutch Amersfoot project in Utrecht involving a new suburb of 501 house covered with PV panels is described. Questions raised regarding architectural integration of PV systems, and PV systems and the construction market are discussed. The Italian PV programme, financial and political constraints, and the positioning of PV on existing structures are reported.

  5. Radiotoxicity and decay heat power of spent nuclear fuel of VVER type reactors at long-term storage.

    Science.gov (United States)

    Bergelson, B R; Gerasimov, A S; Tikhomirov, G V

    2005-01-01

    Radiotoxicity and decay heat power of the spent nuclear fuel of VVER-1000 type reactors are calculated during storage time up to 300,000 y. Decay heat power of radioactive waste (radwaste) determines parameters of the heat removal system for the safe storage of spent nuclear fuel. Radiotoxicity determines the radiological hazard of radwaste after its leakage and penetration into the environment.

  6. 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.)

  7. A Novel Modeling of Molten-Salt Heat Storage Systems in Thermal Solar Power Plants

    Directory of Open Access Journals (Sweden)

    Rogelio Peón Menéndez

    2014-10-01

    Full Text Available Many thermal solar power plants use thermal oil as heat transfer fluid, and molten salts as thermal energy storage. Oil absorbs energy from sun light, and transfers it to a water-steam cycle across heat exchangers, to be converted into electric energy by means of a turbogenerator, or to be stored in a thermal energy storage system so that it can be later transferred to the water-steam cycle. The complexity of these thermal solar plants is rather high, as they combine traditional engineering used in power stations (water-steam cycle or petrochemical (oil piping, with the new solar (parabolic trough collector and heat storage (molten salts technologies. With the engineering of these plants being relatively new, regulation of the thermal energy storage system is currently achieved in manual or semiautomatic ways, controlling its variables with proportional-integral-derivative (PID regulators. This makes the overall performance of these plants non optimal. This work focuses on energy storage systems based on molten salt, and defines a complete model of the process. By defining such a model, the ground for future research into optimal control methods will be established. The accuracy of the model will be determined by comparing the results it provides and those measured in the molten-salt heat storage system of an actual power plant.

  8. Energy Optimization for Transcritical CO2 Heat Pump for Combined Heating and Cooling and Thermal Storage Applications

    DEFF Research Database (Denmark)

    Do Carmo, Carolina Madeira Ramos; Blarke, Morten; Yazawa, Kazuaki

    2012-01-01

    A transcritical heat pump (THP) cycle using carbon dioxide (CO2) as the refrigerant is known to feature an excellent coefficient of performance (COP) as a thermodynamic system. Using this feature, we are designing and building a system that combines a water-to-water CO2 heat pump with both hot...... and cold thermal storages know as Thermal Battery (TB) (Blarke, 2012). Smart and effective use of intermittent renewable energy resources (for example solar and wind power) is obtained supplying water heating (>70 oC) and cooling services (

  9. 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.

  10. Investigation of Sensible and Latent Heat Storage System using various HTF

    Science.gov (United States)

    Beemkumar, N.; Karthikeyan, A.; Manoj, A.; Keerthan, J. S.; Stallan, Joseph Paul; Amithkishore, P.

    2017-05-01

    The objective of the work is investigating the latent heat storage system by varying heat transfer fluid (HTF). In this experiment, the effect of using different heat transfer fluids on the combined system is studied while using a low melting phase change material (PCM) i.e., paraffin wax. The heat transfer fluids chosen are water (low boiling fluid) and Therminol-66 (High boiling fluid). A comparison is made between the heat transfers by employing both the Heat transfer fluids. In the beginning, water is made to flow as the HTF and the charging process is undertaken followed by the discharging process by utilizing the different encapsulation materials namely, copper, aluminium and brass. These processes are then repeated for therminol-66 as HTF. At the end of the experiment it was concluded that even though therminol-66 enhances the latent heat storage capacity, water offers a higher sensible heat storage capacity, making it a better HTF for low melting PCM. Similar to above said process the experiments can be conducted for high and medium range melting point PCM with variation of HTF.

  11. Comparative Heat Conduction Model of a Cold Storage with Puf & Eps Insulation Using Taguchi Methodology

    Directory of Open Access Journals (Sweden)

    Dr. N. Mukhopadhyay

    2015-05-01

    Full Text Available In this project work a mathematical heat conduction model of a cold storage (with the help of computer program; and multiple regression analysis has been proposed which can be used for further development of cold storages in the upcoming future. In cold storage refrigeration system brings down the temperature initially during start up but thermal insulation maintains the temperature later on continuously. In this view, the simple methodology is presented to calculate heat transfer by analytical method also attempt has been made to minimize the energy consumption by replacing 150 mm Expanded polystyrene (EPS by 100 mm Poly Urethane foam (PUF insulation. The methodology is validated against actual data obtained from Penguin cold storage situated in Pune, India. Insulation thickness of the side walls (TW, area of the wall (AW, and insulation thickness of the roof (TR have been chosen as predictor variables of the study.

  12. Numerical simulation on heat transfer characteristics of the storage tank for concentrating solar power plant

    Directory of Open Access Journals (Sweden)

    Qianjun Mao

    2016-06-01

    Full Text Available Concentrating solar power plant coupling with energy storage is a new and emerging technology, which can solve two issues, that is, low flux density and intermittent of solar energy. Heat transfer characteristics of the storage tank in this system have a key effect on the system’s efficiency and cost. In this article, the heat transfer performance of a phase change thermal storage tank has been proposed, and the temperature distribution and liquid fraction of phase change material in the tank has numerically been investigated. The results show that the temperature increases with the increasing charge time. The results also show that there is a phase change process at the charge time of 200 min, and no phase change for the charge time of 250 and 300 min. The results of this article can provide a reference for future design and optimal operation of the storage tank in concentrating solar power plant.

  13. Energy Absorption and Storage in a Hamiltonian System in Partial Contact with a Heat Bath

    CERN Document Server

    Nakagawa, N; Nakagawa, Naoko; Kaneko, Kunihiko

    1999-01-01

    To understand the mechanism allowing for long-term storage of excess energy in proteins, we study a Hamiltonian system consisting of several coupled pendula in partial contact with a heat bath. It is found that energy absorption and storage are possible when the motion of each pendulum switches between oscillatory (vibrational) and rotational modes. The relevance of our mechanism to protein motors is discussed.

  14. Adsorption properties of porous materials for solar thermal energy storage and heat pump applications

    OpenAIRE

    Jänchen, Jochen; Stach, Helmut

    2012-01-01

    The water adsorption properties of modified porous sorbents for solar thermal energy storage and heat transformation have been investigated by thermogravimetry (TG) differential thermogravimetry (DTG), microcalorimetry, measurements of water adsorption isotherms, and storage tests. A chabazite type SAPO, a dealuminated faujasite type zeolite, and a mesostructured aluminosilicate, have been synthesized and compared with common zeolites X, Y and silica gel. It has been found that optimized latt...

  15. 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.

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

    Directory of Open Access Journals (Sweden)

    Mejdi Hazami

    2005-01-01

    Full Text Available The use of solar energy for greenhouse heating has gained an increasing acceptance during the last years. Active solar systems applied to greenhouses can supply a significant part of the heating requirements. However, there are some problems related to the cost of the heat collection unit and the heat storage methods. In this context several techniques were born. The most famous of these techniques is the seasonal storage of thermal heat in soil. The objective of our work is to study a system of thermal energy storage conceived in our Laboratory (LEPT, Tunisia. The system is composed of a vat having a large dimension (6 m3 filled with fin sand. Inside the vat three batteries of capillary exchangers are buried at three different levels. To heat the accumulator soil, we use a solar collector with a surface equal to 6 m2. In order to size the heat accumulating system, a numerical study is started. It allows evaluating the soil temperature as well as the energy cumulated inside the accumulator during the charging and the discharging period.

  17. 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...... the supercooled sodium acetate water mixture was 194 kJ/kg of sodium acetate water mixture in the first test cycles dropping to 179 kJ/kg in the later test cycles. Instability of the supercooling occurred when the charging periods were short and in the last test cycles where the tube connecting the module...

  18. 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...

  19. Heat transfer enhancement through PCM thermal storage by use of copper fins

    Directory of Open Access Journals (Sweden)

    Rudonja Nedžad R.

    2016-01-01

    Full Text Available Enhancement of heat transfer over a cylinder shaped thermal energy storage filled by paraffin E53 by use of radial rectangular copper fins was analyzed. The thermo-physical features of the storage material are determined in separate experiments and implemented to Fluent software over UDF. Advanced thermal storage geometry comprehension and optimization required introduction of a parameter suitable for the analysis of heat transfer enhancement, so the ratio of heat transfer surfaces as a factor was proposed and applied. It is revealed that increase of the ratio of heat transfer surfaces leads to the decrease of melting time and vice versa. Numerical analysis, employing the 3D model built in Ansys software, observed storage reservoir geometries with variable number of longitudinal radial fins. The adjusted set of boundary conditions was carried out and both written in C language and implemented over UDF in order to define variable heat flux along the height of the heater. The comparison of acquired numerical and experimental results showed a strong correlation. Experimental validation of numerical results was done on the real TES apparatus. [Projekat Ministarstva nauke Republike Srbije, br. III42011, TR 33042 i OI 176006

  20. Numerical and Experimental Investigation of Natural Convection in Open-Ended Channels with Application to Building Integrated Photovoltaic (BIPV Systems

    Directory of Open Access Journals (Sweden)

    Timchenko V.

    2015-01-01

    Full Text Available Numerical and experimental investigations of the flow and heat transfer in open-ended channel formed by the double skin façade have been undertaken in order to improve understanding of the phenomena and to apply it to passive cooling of building integrated photovoltaic systems. Both uniform heating and non-uniform heating configurations in which heat sources alternated with unheated zones on both skins were studied. Different periodic and asymmetric heating modes have been considered for the same aspect ratio 1/15 of wall distance to wall height and for periodicity 1/15 and 4/15 of heated/unheated zones and heat input, 220 W/m2. In computational study three dimensional transient LES simulation was carried out. It is shown that in comparison to uniformly heating configuration, non-uniformly heating configuration enhances both convective heat transfer and chimney effect.

  1. Thermal cycle testing of calcium chloride hexahydrate as a possible PCM for latent heat storage

    Energy Technology Data Exchange (ETDEWEB)

    Tyagi, V.V.; Buddhi, D. [Thermal Energy Storage Laboratory, School of Energy and Environmental Studies, Devi Ahilya University, Indore 452017 (India)

    2008-08-15

    In order to study the changes in latent heat of fusion and melting temperature of calcium chloride hexahydrate (CaCl{sub 2}.6H{sub 2}O) inorganic salt as a latent heat storage material, a thousand accelerated thermal cycle tests have been conducted. The effect of thermal cycling and the reliability in terms of the changing of the melting temperature using a differential scanning calorimeter (DSC) is determined. It has been noticed that the CaCl{sub 2}.6H{sub 2}O melts between a stable range of temperature and has shown small variations in the latent heat of fusion during the thermal cycling process. Thus, it can be a promising phase change material (PCM) for heating and cooling applications for various building/storage systems. (author)

  2. 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)

    Leeuwen, van R.P.; Wit, de J.B.; Fink, J.; Smit, G.J.M.

    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 lim

  3. 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 lim

  4. Experimental evaluation of commercial heat exchangers for use as PCM thermal storage systems

    Energy Technology Data Exchange (ETDEWEB)

    Medrano, M.; Nogues, M.; Martorell, I.; Roca, Joan; Cabeza, Luisa F. [Centre GREA, Pere de Cabrera s/n, Universitat de Lleida, 25001 Lleida (Spain); Yilmaz, M.O. [Chemical Department, Cukurova University, Adana (Turkey)

    2009-10-15

    Phase change materials (PCM) possess a great capacity of accumulation of energy in their temperature of fusion thanks to the latent heat. These materials are used in applications where it is necessary to store energy due to the temporary phase shift between the offer and demand of thermal energy. Thus, possible applications are the solar systems as well as the recovery of residual heat for its posterior use in other processes. In spite of this great potential, the practical feasibility of latent heat storage with PCM is still limited, mainly due to a rather low thermal conductivity. This low conductivity implies small heat transfer coefficients and, consequently, thermal cycles are slow and not suitable for most of the potential applications. This work investigates experimentally the heat transfer process during melting (charge) and solidification (discharge) of five small heat exchangers working as latent heat thermal storage systems. Commercial paraffin RT35 is used as PCM filling one side of the heat exchanger and water circulates through the other side as heat transfer fluid. Average thermal power values are evaluated for various operating conditions and compared among the heat exchangers studied. When the comparison is done for average power per unit area and per average temperature gradient, results show that the double pipe heat exchanger with the PCM embedded in a graphite matrix (DPHX-PCM matrix) is the one with higher values, in the range of 700-800 W/m{sup 2}-K, which are one order of magnitude higher than the ones presented by the second best. On the other hand, the compact heat exchanger (CompHX-PCM) is by large the one with the highest average thermal power (above 1 kW), as it has the highest ratio of heat transfer area to external volume. (author)

  5. Development of in-aquifer heat testing for high resolution subsurface thermal-storage capability characterisation

    Science.gov (United States)

    Seibertz, Klodwig Suibert Oskar; Chirila, Marian Andrei; Bumberger, Jan; Dietrich, Peter; Vienken, Thomas

    2016-03-01

    The ongoing transition from fossil fuels to alternative energy source provision has resulted in increased geothermal uses as well as storage of the shallow subsurface. Existing approaches for exploration of shallow subsurface geothermal energy storage often lack the ability to provide information concerning the spatial variability of thermal storage parameters. However, parameter distributions have to be known to ensure that sustainable geothermal use of the shallow subsurface can take place - especially when it is subject to intensive usage. In this paper, we test a temperature decay time approach to obtain in situ, direct, qualitative, spatial high-resolution information about the distribution of thermal storage capabilities of the shallow subsurface. To achieve this, temperature data from a high-resolution Fibre-Optic-Distributed-Temperature-Sensing device, as well as data from conventional Pt100-temperature-sensors were collected during a heat injection test. The latter test was used to measure the decay time of temperature signal dissipation of the subsurface. Signal generation was provided by in-aquifer heating with a temperature self-regulating electric heating cable. Heating was carried out for 4.5 days. After this, a cooling period of 1.5 weeks was observed. Temperature dissipation data was also compared to Direct-Push-derived high-resolution (hydro-)geological data. The results show that besides hydraulic properties also the bedding and compaction state of the sediment have an impact on the thermal storage capability of the saturated subsurface. The temperature decay time approach is therefore a reliable method for obtaining information regarding the qualitative heat storage capability of heterogeneous aquifers for the use with closed loop system geothermal storage systems. Furthermore, this approach is advantageous over other commonly used methods, e.g. soil-sampling and laboratory analysis, as even small changes in (hydro-)geological properties lead to

  6. A comparison of heat transfer enhancement in a medium temperature thermal energy storage heat exchanger using fins

    Energy Technology Data Exchange (ETDEWEB)

    Agyenim, Francis; Smyth, Mervyn [Centre for Sustainable Technologies, University of Ulster, Newtownabbey BT37 0QB (United Kingdom); Eames, Philip [Electronic and Electrical Engineering, Loughborough University, Leicestershire LE11 3TU (United Kingdom)

    2009-09-15

    An experimental energy storage system has been designed using a horizontal concentric tube heat exchanger incorporating a medium temperature phase change material (PCM) Erythritol, with a melting point of 117.7 C. Three experimental configurations, a control system with no heat transfer enhancement and systems augmented with circular and longitudinal fins have been studied. The results presented compare the system heat transfer characteristics using isotherm plots and temperature-time curves. The system with longitudinal fins gave the best performance with increased thermal response during charging and reduced subcooling in the melt during discharging. The experimentally measured data for the control, circular finned and longitudinal finned systems have been shown to vindicate the assumption of axissymmetry (direction parallel to the heat transfer fluid flow) using temperature gradients in the axial, radial and angular directions in the double pipe PCM system. (author)

  7. 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

  8. 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...

  9. Eutectic mixtures of capric acid and lauric acid applied in building wallboards for heat energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Lv Shilei; Zhu Neng [Tianjin University (China). School of Environmental Science and Technology; Feng Guohui [Shenyang Jianzhu University, Shenyang (China)

    2006-06-15

    Capric acid (CA) and lauric acid (LA), as phase change materials (PCM), can be applied for energy storage in low temperature. The phase transitions temperature and values of latent heat of eutectic mixtures of CA and LA are suitable for being incorporated with building materials to form phase change wallboards used for building energy storage. 120, 240 and 360 accelerated thermal cycle tests were conducted to study the changes in latent heat of fusion and melting temperature of phase change wallboards combined with the eutectic mixtures of CA and LA. Differential scanning calorimetry (DSC) tested the transition temperature and latent heat. The results showed that the melting temperature and latent heat of these phase change wallboards with eutectic mixtures have not obvious variations after repeated 360 thermal cycles, which proved that these phase change wallboards have good thermal stability for melting temperature and variations in latent heat of fusion for long time application. Therefore, they can be used for latent heat storage in the field of building energy conservation. (author)

  10. Eutectic mixtures of capric acid and lauric acid applied in building wallboards for heat energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Shilei, L.; Neng, Z. [School of Environment Science and Technology, Tianjin University, Tianjin (China); Guohui, F. [Shenyang Jianzhu University, Shenyang (China)

    2006-07-01

    Capric acid (CA) and lauric acid (LA), as phase change materials (PCM), can be applied for energy storage in low temperature. The phase transition temperature and values of latent heat of eutectic mixtures of CA and LA are suitable for being incorporated with building materials to form phase change wallboards used for building energy storage. 120, 240 and 360 accelerated thermal cycle tests were conducted to study the changes in latent heat of fusion and melting temperature of phase change wallboards combined with the eutectic mixtures of CA and LA. Differential scanning calorimetry (DSC) tested the transition temperature and latent heat. The results showed that the melting temperature and latent heat of these phase change wallboards with eutectic mixtures have no obvious variations after repeated 360 thermal cycles, which proved that these phase change wallboards have good thermal stability for melting temperature and variations in latent heat of fusion for long time application. Therefore, they can be used for latent heat storage in the field of building energy conservation. (author)

  11. 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.

  12. 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

    unit was tested with 116.3 kg SAT with 0.5% Xanthan rubber as a thickening agent and 4.4% graphite powder. The heat exchange capacity rate during charge was significantly lower for the unit with SAT and Xanthan rubber compared to the unit with SAT and extra water. This was due to less convection......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...

  13. Influence of wind power, plug-in electric vehicles, and heat storages on power system investments

    DEFF Research Database (Denmark)

    Kiviluoma, Juha; Meibom, Peter

    2010-01-01

    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.......Due to rising fuel costs, the substantial price for CO2 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...

  14. Application of MgCl{sub 2.}6H{sub 2}O for thermochemical seasonal solar heat storage

    Energy Technology Data Exchange (ETDEWEB)

    Zondag, H.A. [Energy Research Centre of the Netherlands (ECN), Petten (Netherlands); Eindhoven Univ. of Technology (Netherlands). Dept. of Mechanical Engineering; Essen, V.M. van; Bleijendaal, L.P.J.; Kikkert, B.W.J.; Bakker, M. [Energy Research Centre of the Netherlands (ECN), Petten (Netherlands)

    2010-07-01

    The heat demand in the summer can be completely fulfilled using solar heat, but in the winter the heat demand is exceeding the solar supply. A solution is to store the excess of solar energy in the summer, and to use it to fulfill the heat demand in the winter. Water is traditionally used for storing heat (e.g. solar boiler), but seasonal heat storage requires large water tanks (>40m{sup 3}) that are too large to be placed inside a family building. An alternative option is to store heat by means of chemical processes using the reversible reaction: A+B<=>C+heat. With thermochemical heat storage, energy storage densities can be reached that are ten times higher than for heat storage in water. Additionally, after the thermochemical material has been charged, the heat can be stored for a very long time without losses. Interesting materials are cheap, non-toxic, non-corrosive, have sufficient energy storage density and have reaction temperatures in the proper range. A large materials inventory by ECN identified a number of interesting materials, including magnesium chloride hexahydrate (MgCl{sub 2.}6H{sub 2}O) as one of the most promising materials for seasonal heat storage (Zondag, 2007). (orig.)

  15. Application of MgCl2.6H2O for thermochemical seasonal solar heat storage

    Energy Technology Data Exchange (ETDEWEB)

    Zondag, H.A. [Eindhoven University of Technology, Eindhoven (Netherlands); Van Essen, V.M.; Bleijendaal, L.P.J.; Kikkert, B.W.J.; Bakker, M. [ECN Solar Energy, Petten (Netherlands)

    2010-11-15

    The heat demand in the summer can be completely fulfilled using solar heat, but in the winter the heat demand is exceeding the solar supply. A solution is to store the excess of solar energy in the summer, and to use it to fulfill the heat demand in the winter. Water is traditionally used for storing heat (e.g. solar boiler), but seasonal heat storage requires large water tanks (>40m{sup 3}) that are too large to be placed inside a residential building. An alternative option is to store heat by means of chemical processes using the reversible reaction: A+B->C+heat. With thermochemical heat storage, energy storage densities can be reached that are ten times higher than for heat storage in water. Additionally, after the thermochemical material has been charged, the heat can be stored for a very long time without losses. Interesting materials are cheap, non-toxic, non-corrosive, have sufficient energy storage density and have reaction temperatures in the proper range. A large materials inventory by ECN identified a number of interesting materials, including magnesium chloride hexahydrate (MgCl2.6H2O) as one of the most promising materials for seasonal heat storage.

  16. 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.

  17. Study and Test of Cold Storage Heat Recovery Heat Pump Coupled Solar Drying Device

    Directory of Open Access Journals (Sweden)

    Min Li

    2013-05-01

    Full Text Available In this study, we design the recovery of a heat pump combined solar drying device. Then, with this device, drying experiments of aquatic product, tilapia, were conducted, indicating that the newly designed device functions are well in temperature adjusting and controlling performance and showing that drying time is closely related to energy consumption and drying conditions. Heat recovery heat pump combined solar energy drier can improve the drying quality of aquatic products, but also can greatly reduce the drying energy consumption, which provides theoretical support to the design and processing of heat recovery heat pump of refrigeration system coupled solar drying device.

  18. 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...... as the theoretical results obtained for a solar combi system with the PCM-storage installed in a low energy house in a Danish climate. Parametric studies of collector area, storage volume and solar fraction for the PCM-system will be presented as well as an outline for a system with 100% coverage of the space...... 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...

  19. Heat storage by phase transition, equation of state

    Energy Technology Data Exchange (ETDEWEB)

    Stunic, Z.

    1984-01-01

    Incongruent phase transitions accompanied by phase separation frequently cause a deterioration of heat-of-fusion storing systems. This kind of deterioration progresses, cycle after cycle, and is especially damaging in technical devices in which hydrated salts, e.g. CaCl/sub 2/ x 6H/sub 2/O, Na/sub 2/SO/sub 4/ x 10H/sub 2/O, Na/sub 2/S/sub 2/O/sub 3/ x 5H/sub 2/O, etc., are used as heat storing materials. Processes contributing to deterioration of hydrated-salt systems are analyzed, novel thermodynamic characteristics are proposed to enable unambiguous descriptions, and these are related in an equation of state for triads of characteristics so that any one of them can be calculated if the other two are known. State equations fo the three salts mentioned above are represented graphically in three-dimensional diagrams. Predictions deduced from state equations are tested experimentally with systems undergoing rapid (or purely incongruent) and slow (or pseudocongruent) phase transitions (CaCl/sub 2/ x 6H/sub 2/O and Na/sub 2/SO/sub 4/ 10H/sub 2/O, respectively). Good accordance between prognosis and experiment is shown.

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

    Science.gov (United States)

    Bootle, John

    2008-01-01

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

  1. Thermal energy storage for electricity-driven space heating in a day-ahead electricity market

    DEFF Research Database (Denmark)

    Pensini, Alessandro

    2012-01-01

    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...

  2. 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

  3. 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

  4. 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

    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...

  5. 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

  6. Experimental studies for the cyclability of salt hydrates for thermochemical heat storage

    NARCIS (Netherlands)

    Donkers, P.A.J.; Pel, L.; Adan, O.C.G.

    2016-01-01

    Salt hydrates have promising potential as heat storage materials by use of their hydration/dehydration reaction. These hydration/dehydration reactions are studied in this paper for CuCl2, CuSO4, MgCl2 and MgSO4. During a hydration/dehydration reaction, the salt shrinks and expands as a result of the

  7. A predictive model for smart control of a domestic heat pump and thermal storage

    NARCIS (Netherlands)

    Leeuwen, van R.P.; Gebhardt, I.; Wit, de J.B.; Smit, G.J.M.

    2016-01-01

    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 t

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

    NARCIS (Netherlands)

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

    2016-01-01

    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 cor

  9. Modeling and Control of Heat Networks With Storage : The Single-Producer Multiple-Consumer Case

    NARCIS (Netherlands)

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

    2016-01-01

    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 co

  10. 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.

  11. Heat transfer and thermal storage behaviour of gypsum boards incorporating micro-encapsulated PCM

    Energy Technology Data Exchange (ETDEWEB)

    Lai, Chi-ming [Department of Civil Engineering, National Cheng-Kung University, 1, University Road, Tainan City 701 (China); Chen, R.H.; Lin, Ching-Yao [Department of Mechanical Engineering, Southern Taiwan University (China)

    2010-08-15

    In the application of energy storage and thermal environmental control, PCM (Phase Change Material) is a very promising material choice. This study incorporated mPCM (micro-encapsulated PCM) into gypsum to make mPCM gypsum board and then investigated the physical properties, heat transfer and thermal storage behaviour. The major control parameters are wall temperatures and the weight percentages of mPCM added to the gypsum boards. A melting fraction correlation, reduced from our test data and based on Stefan number (Ste), subcooling (Sb) and Fourier number, is proposed. It shows that case with a higher Ste or Sb can have a higher heat transfer through the hot wall. Thermal storage behaviour of mPCM gypsum boards is then analyzed. (author)

  12. Sulfur Based Thermochemical Heat Storage for Baseload Concentrated Solar Power Generation

    Energy Technology Data Exchange (ETDEWEB)

    wong, bunsen

    2014-11-20

    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.

  13. 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.

  14. Evaluation of a sulfur oxide chemical heat storage process for a steam solar electric plant

    Energy Technology Data Exchange (ETDEWEB)

    Dayan, J.; Lynn, S.; Foss, A.

    1979-07-01

    The purpose of this study was to develop and evaluate technically feasible process configurations for the use of the sulfur oxide system, 2 SO/sub 3/ reversible 2 SO/sub 2/ + O/sub 2/, in energy storage. The storage system is coupled with a conventional steam-cycle power plant. Heat for both the power plant and the storage system is supplied during sunlit hours by a field of heliostats focussed on a central solar receiver. When sunlight is not available, the storage system supplies the heat to operate the power plant. A technically feasible, relatively efficient configuration is proposed for incorporating this type of energy storage system into a solar power plant. Complete material and energy balances are presented for a base case that represents a middle range of expected operating conditions. Equipment sizes and costs were estimated for the base case to obtain an approximate value for the cost of the electricity that would be produced from such an installation. In addition, the sensitivity of the efficiency of the system to variations in design and operating conditions was determined for the most important parameters and design details. In the base case the solar tower receives heat at a net rate of 230 MW(t) for a period of eight hours. Daytime electricity is about 30 MW(e). Nighttime generation is at a rate of about 15 MW(e) for a period of sixteen hours. The overall efficiency of converting heat into electricity is about 26%. The total capital cost for the base case is estimated at about $68 million, of which about 67% is for the tower and heliostats, 11% is for the daytime power plant, and 22% is for the storage system. The average cost of the electricity produced for the base case is estimated to be about 11 cents/kW(e)-hr.

  15. Energy performance and economic evaluation of heat pump/organic rankine cycle system with sensible thermal storage

    DEFF Research Database (Denmark)

    Carmo, Carolina; Dumont, Olivier; Nielsen, Mads Pagh

    2016-01-01

    -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...... 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...

  16. 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.

  17. 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.

  18. New latent heat storage system with nanoparticles for thermal management of electric vehicles

    Science.gov (United States)

    Javani, N.; Dincer, I.; Naterer, G. F.

    2014-12-01

    In this paper, a new passive thermal management system for electric vehicles is developed. A latent heat thermal energy storage with nanoparticles is designed and optimized. A genetic algorithm method is employed to minimize the length of the heat exchanger tubes. The results show that even the optimum length of a shell and tube heat exchanger becomes too large to be employed in a vehicle. This is mainly due to the very low thermal conductivity of phase change material (PCM) which fills the shell side of the heat exchanger. A carbon nanotube (CNT) and PCM mixture is then studied where the probability of nanotubes in a series configuration is defined as a deterministic design parameter. Various heat transfer rates, ranging from 300 W to 600 W, are utilized to optimize battery cooling options in the heat exchanger. The optimization results show that smaller tube diameters minimize the heat exchanger length. Furthermore, finned tubes lead to a higher heat exchanger length due to more heat transfer resistance. By increasing the CNT concentration, the optimum length of the heat exchanger decreases and makes the improved thermal management system a more efficient and competitive with air and liquid thermal management systems.

  19. 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

    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...... 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...

  20. Study and Test of Cold Storage Heat Recovery Heat Pump Coupled Solar Drying Device

    OpenAIRE

    Min Li; Xiao-Qiang Jiang; Bao-Chuan Wu

    2013-01-01

    In this study, we design the recovery of a heat pump combined solar drying device. Then, with this device, drying experiments of aquatic product, tilapia, were conducted, indicating that the newly designed device functions are well in temperature adjusting and controlling performance and showing that drying time is closely related to energy consumption and drying conditions. Heat recovery heat pump combined solar energy drier can improve the drying quality of aquatic products, but also can gr...

  1. 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.

  2. Influence of void ratio on phase change of thermal energy storage for heat pipe receiver

    Directory of Open Access Journals (Sweden)

    Xiaohong Gui

    2015-01-01

    Full Text Available In this paper, influence of void ratio on phase change of thermal storage unit for heat pipe receiver under microgravity is numerically simulated. Accordingly, mathematical model is set up. A solidification-melting model upon the enthalpy-porosity method is specially provided to deal with phase changes. The liquid fraction distribution of thermal storage unit of heat pipe receiver is shown. The fluctuation of melting ratio in PCM canister is indicated. Numerical results are compared with experimental ones in Japan. The results show that void cavity prevents the process of phase change greatly. PCM melts slowly during sunlight periods and freezes slowly during eclipse periods as void ratio increases. The utility ratio of PCM during both sunlight periods and eclipse periods decreases obviously with the improvement of void ratio. The thermal resistance of void cavity is much higher than that of PCM canister wall. Void cavity prevents the heat transfer between PCM zone and canister wall.

  3. PREPARATION OF PUZZOLANA ACTIVE TWO COMPONENT COMPOSITE FOR LATENT HEAT STORAGE

    Directory of Open Access Journals (Sweden)

    Jan Fort

    2016-10-01

    Full Text Available Application of Phase Change Materials (PCMs represents promising way for an increase of energy efficiency of industrial devices, reduction of energy demands for heating and cooling, waste heat recovery, solar energy storage and smart control of buildings interior climate. In this paper, the potential of diatomite as the bearer for the shape stable PCM was studied in order to develop material applicable in the mix composition of composite materials. Considering availability, endurance and compatibility of diatomite with the cement and lime based materials, preparation of diatomite/wax composite brings pozzolana active PCM with great promises at a reasonable cost. Prepared composite was analysed in detail using laser diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy and differential scanning calorimetry. Also the pozzolanic activity was measured. The prepared two components composite exhibits high latent heat storage and particle size distribution compatible with cement and hydrated lime.

  4. [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.

  5. Three-Dimensional Heat Transfer Analysis for A Thermal Energy Storage Canister

    Institute of Scientific and Technical Information of China (English)

    Hou Xinbin; Xin Yuming; Yang Chunxin; Yuan Xiugan; Dong Keyong

    2001-01-01

    High temperature latent thermal storage is one of the critical techniques for a solar dynamic power system. This paper presents results from heat transfer analysis of a phase change salt containment canister. A three dimensional analysis program is developed to model heat transfer in a PCM canister. Analysis include effects of asymmetric circumference heat flux, conduction in canister walls, liquid PCM and solid PCM, void volume change and void location, and conduction and radiation across PCM vapor void. The PCM phase change process is modeled using the enthalpy method and the simulation results are compared with those of other two dimensional investigations. It's shown that there are large difference with two-dimensional analysis, therefore the three-dimensional model is necessary for system design of high temperature latent thermal storage.

  6. Numerical heat transfer studies of the fatty acids for different heat exchanger materials on the performance of a latent heat storage system

    Energy Technology Data Exchange (ETDEWEB)

    Atul Sharma; Lee Dong Won; Jun Un Park [Korea Institute of Energy Research, Daejeon (Korea). Solar Thermal Research Centre; Buddhi, D. [Devi Ahilya University, Indore (India). Thermal Energy Storage Laboratory

    2005-11-01

    Theoretical investigations of fatty acids as a phase change material (PCM) for energy storage system have been conducted in this study. The selected fatty acids were capric acid, lauric acid, myristic acid, palmitic acid and stearic acid. For the two-dimensional simulation model based on the enthalpy approach, calculations have been made for the melt fraction with conduction only. Glass, stainless steel, tin, aluminium mixed, aluminium and copper were used as heat exchanger materials in the numerical calculations. Theoretical results show that capric acid was found good compatibility with latent heat storage system. The large value of thermal conductivity of heat exchanger materials did not make significant contribution on the melt fraction. (author)

  7. Solar assisted absorption or motor driven heat pump with earth seasonal storage. Final report. Pt. 1 and 2

    Energy Technology Data Exchange (ETDEWEB)

    Lazzarin, R.M.

    1987-01-01

    A plant composed of an energy roof, a seasonal earth storage and an absorption heat pump has been experimented. The purpose was to study the behaviour of the various components and their interaction. The surveys went on during two years. The following operations are considered: The charging of the earth storage by the energy roof and the working of an absorption heat pump connected either to the energy roof or to the earth storage.

  8. 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

  9. 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.

  10. 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.

  11. 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.

  12. Theoretical Convective Heat Transfer Model Developement of Cold Storage Using Taguchi Analysis.

    Directory of Open Access Journals (Sweden)

    Dr.N.Mukhopadhyay

    2015-01-01

    Full Text Available Energy crisis is one of the most important problems the world is facing now-a-days. With the increase of cost of electrical energy operating cost of cold storage storing is increasing which forces the increased cost price of the commodities that are kept. In this situation if the maximum heat energy(Q is absorbed by the evaporator inside the cold room through convective heat transfer process in terms of –heat transfer due to convection and heat transfer due to condensation, more energy has to be wasted to maintain the evaporator space at the desired temperature range of 2- 8 degree centigrade. In this paper we have proposed a theoretical heat transfermodel of convective heat transfer incold storage using Taguchi L9 orthogonal array. Velocity of air(V, Temperature difference(dT, RelativeHumidity(RHare the basic variable and three ranges are taken each of them in the model development. Graphical interpretations from the model justifies the reality

  13. Characterisation of the bacterial populations in a saline heat storage aquifer in the North German Basin

    Science.gov (United States)

    Alawi, M.; Lerm, S.; Vetter, A.; Vieth, A.; Mangelsdorf, K.; Seibt, A.; Wolfgramm, M.; Würdemann, H.

    2009-04-01

    The colonization and the ecology of microorganisms in the deep biosphere arouse increasing interest of scientists because of utilizing the subsurface for e.g. energy storage and recovery. The research project AquiScreen investigates the operational reliability of eight geothermally used groundwater systems in Germany under microbial, geochemical, mineralogical, and petrological aspects. This study shows the results of the heat storage in Neubrandenburg (depth: 1250 m), a typical site for saline fluids in the North German Basin. The seasonal alternation in charge and discharge mode enabled sampling the warm (75˚ C) and the cold (45˚ C) side of the geothermal doublet. The analyses focus on microbially induced corrosion on plant components and scaling resulting in filter and/or formation clogging. Microbiological analyses were carried out with fluid and solid phase samples by 16S rDNA based Single Strand Conformation Polymorphism (SSCP) fingerprinting. The analyses are utilized to evaluate the impact of microbial populations on such systems. The genetic fingerprinting revealed significant differences in the bacterial community structure between the warm and cold side of the heat storage. Since the geochemical analyses revealed no remarkable differences, the temperature might be crucial for the different community structures. At the warm side of the aquifer the identified bacteria are closely related to Variovorax and Sphingomonas. At the cold side of the heat storage sulphate reducing and fermentative bacteria were detected. These results correspond with locally observed iron sulphide precipitation and corrosion processes on plant components. Particularly the bacterial population of the cold side was studied over a period of two years. Thereby seasonal changes in the abundance of the identified bacteria, depending on the operational mode of the geothermal plant, were observed. After a malfunction in the pump system of the cold side of the heat storage changes in

  14. 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.

  15. Review on thermal energy storage with phase change: materials, heat transfer analysis and applications

    Energy Technology Data Exchange (ETDEWEB)

    Zalba, Belen; Marin, Jose M. [Dpto. Ingenieria Mecanica, Campus Politecnico, Universidad de Zaragoza, EUITIZ ' EDIFICIO B.3' Maria de Luna 3 (Actur), 50015, Zaragoza (Spain); Cabeza, Luisa F. [Dpt.d' Informatica i Enginyeria Industrial, Escola, Universitaria Politecnica, Universitat de Lleida, CREA, Jaurne 11,69,25001, Lleida (Spain); Mehling, Harald [ZAE Bayem, Division 1: Energy Conversion and Storage, Walther-Meissner-Str. 6, 85748, Garching (Germany)

    2003-02-01

    Thermal energy storage in general, and phase change materials (PCMs) in particular, have been a main topic in research for the last 20 years, but although the information is quantitatively enormous, it is also spread widely in the literature, and difficult to find. In this work, a review has been carried out of the history of thermal energy storage with solid-liquid phase change. Three aspects have been the focus of this review: materials, heat transfer and applications. The paper contains listed over 150 materials used in research as PCMs, and about 45 commercially available PCMs. The paper lists over 230 references. (Author)

  16. THERMOCHEMICAL ENERGY STORAGE FOR SEASONAL BALANCE OF SURPLUS ELECTRICITY AND HEAT DEMAND IN DOMESTIC BUILDINGS

    OpenAIRE

    Schmidt, Matthias; Linder, Marc Philipp

    2016-01-01

    Thermochemical storage systems are predestined to store thermal energy for a long time since the storage principle itself is free of losses and allows for very high energy densities. Therefore we developed a new approach where electricity, p. e. from private PV-panels in the summer, is used to charge a thermochemical reaction system. The reaction product then can be stored in an inexpensive tank at room temperature. If there is heat demand during the winter part of the material can be supplie...

  17. Thermal Storage System for Electric Vehicle Cabin Heating Component and System Analysis

    Energy Technology Data Exchange (ETDEWEB)

    LaClair, Tim J [ORNL; Gao, Zhiming [ORNL; Abdelaziz, Omar [ORNL; Wang, Mingyu [MAHLE Behr Troy Inc.; WolfeIV, Edward [MAHLE Behr Troy Inc.; Craig, Timothy [MAHLE Behr Troy Inc.

    2016-01-01

    Cabin heating of current electric vehicle (EV) designs is typically provided using electrical energy from the traction battery, since waste heat is not available from an engine as in the case of a conventional automobile. In very cold climatic conditions, the power required for space heating of an EV can be of a similar magnitude to that required for propulsion of the vehicle. As a result, its driving range can be reduced very significantly during the winter season, 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 from an advanced phase change material (PCM) has been designed for use in EVs and plug-in hybrid electric vehicles (PHEVs). The present paper focuses on the modeling and analysis of this electrical PCM-Assisted Thermal Heating System (ePATHS) and is a companion to the paper Design and Testing of a Thermal Storage System for Electric Vehicle Cabin Heating. A detailed heat transfer model was developed to simulate the PCM heat exchanger that is at the heart of the ePATHS and was subsequently used to analyze and optimize its design. The results from this analysis were integrated into a MATLAB Simulink system model to simulate the fluid flow, pressure drop and heat transfer in all components of the ePATHS. The system model was then used to predict the performance of the climate control system in the vehicle and to evaluate control strategies needed to achieve the desired temperature control in the cabin. The analysis performed to design the ePATHS is described in detail and the system s predicted performance in a vehicle HVAC system is presented.

  18. Comparative Study on Methods for Computing Soil Heat Storage and Energy Balance in Arid and Semi-Arid Areas

    Institute of Scientific and Technical Information of China (English)

    LI Yuan; LIU Shuhua; WANG Shu; MIAO Yucong; CHEN Bicheng

    2014-01-01

    Observations collected in the Badan Jaran desert hinterland and edge during 19-23 August 2009 and in the Jinta Oasis during 12-16 June 2005 are used to assess three methods for calculating the heat storage of the 5-20-cm soil layer. The methods evaluated include the harmonic method, the conduction-convection method, and the temperature integral method. Soil heat storage calculated using the harmonic method provides the closest match with measured values. The conduction-convection method underestimates nighttime soil heat storage. The temperature integral method best captures fluctuations in soil heat storage on sub-diurnal timescales, but overestimates the amplitude and peak values of the diurnal cycle. The relative performance of each method varies with the underlying land surface. The land surface energy balance is evaluated using observations of soil heat flux at 5-cm depth and estimates of ground heat flux adjusted to account for soil heat storage. The energy balance closure rate increases and energy balance is improved when the ground heat flux is adjusted to account for soil heat storage. The results achieved using the harmonic and temperature integral methods are superior to those achieved using the conduction-convection method.

  19. 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

  20. 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.

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

    Science.gov (United States)

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

    1980-04-01

    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.

  2. 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.

  3. 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.

  4. Study on latent heat thermal energy storage using aqueous solution as PCM

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Yujiro; Kunimine, Kanji; Yamaguchi, Kunihiko

    1988-02-25

    The latent heat thermal storage where a aqueous solution was used as the phase change material(PCM), was studied. A cold medium was transported into a heat transfer tube in a shell and tube heat exchanger and the heat exchanging experiment with salt solutions of 0-15% concentrations in the shell was carried out. Translucent solidified layer appeared near the inlet area at the early stage and grew to radial and axial directions. The outside layer was a translucent coexisting solid pfase and liquid phase and inner cloudy layer was a eutectic ice solid phase. The PCM was cooled rapidly at the early stage, became the coexisted solid and liquid after 30 minites, and completed solidification, becoming the perfect solid after 100 minites. The exothermic process was composed of the initial releasing process of liquid sensible heat, following exthermic process by release of solidifying latent heat and the final releasing process of remaining sensible heat. The experimental results agreed qulitatively with the theoretical analysis. Because the liquid solidification proceeded with a temperature width, the axial solidification was mitgated, the exothermic rate was stabilized especially at high concentration and the heat exchanging performance was maintained for a long period. (7 figs, 6 refs)

  5. Study on the Performance of a Ground Source Heat Pump System Assisted by Solar Thermal Storage

    Directory of Open Access Journals (Sweden)

    Yu Jin Nam

    2015-11-01

    Full Text Available A ground source heat pump system (GSHPS utilizes a relatively stable underground temperature to achieve energy-saving for heating and cooling in buildings. However, continuous long-term operation will reduce the soil temperature in winter, resulting in a decline in system performance. In this research, in order to improve the system performance of a GSHPS, a ground heat pump system integrated with solar thermal storage was developed. This solar-assisted ground heat pump system (SAGHPS can both maintain the balance of the soil temperature effectively and achieve higher system performance than the conventional system. In this paper, in order to examine the characteristics of the system, a dynamic simulation was conducted under various conditions. The results of our case study provide specific operation data such as heat exchange rate, heat source temperature, and heat pump COP. As a result, the heat pump COP of SAGHPS was 4.7%, 9.3% higher than that of the GSHPS.

  6. A key review of building integrated photovoltaic (BIPV systems

    Directory of Open Access Journals (Sweden)

    Emrah Biyik

    2017-06-01

    The two fundamental research areas in the BIPV and BIPVT systems are observed to be i improvements on system efficiency by ventilation, hence obtaining a higher yield with lowering the panel temperature ii new thin film technologies that are well suited for building integration. Several approaches to achieve these objectives are reported in the literature as presented in this paper. It is expected that this comprehensive review will be beneficial to researchers and practitioners involved or interested in the design, analysis, simulation, and performance evaluation, financial development and incentives, new methods and trends of BIPV systems.

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

    Science.gov (United States)

    Tabassum, Tonny

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

  8. Numerical computation of solar heat storage in phase change material/concrete wall

    Directory of Open Access Journals (Sweden)

    Mustapha Faraji

    2014-01-01

    Full Text Available A one-dimensional mathematical model was developed in order to analyze and optimize the latent heat storage wall. Two layers of phase change material (PCM are sandwiched within a concrete wall. The governing equations for energy transport were developed by using the enthalpy method and discretized with volume control scheme. A series of numerical investigations were conducted. The effect of the melting temperature on the possibility of increasing the energy performance of the proposed heating system was analyzed. Results are obtained for thermal gain and temperature fluctuation. The charging/discharging process was also presented and analyzed.

  9. 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

    was filled with 220 kg SAT mixture thickened with 1% carboxymethyl cellulose. The heat exchange capacity rate during the charging of the unit with the extra water was significantly higher than for the unit with the thickening agent due to the different levels of convection. The SAT mixtures in the units were......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...

  10. Facile synthesis of graphene oxide-modified lithium hydroxide for low-temperature chemical heat storage

    Science.gov (United States)

    Yang, Xixian; Huang, Hongyu; Wang, Zhihui; Kubota, Mitsuhiro; He, Zhaohong; Kobayashi, Noriyuki

    2016-01-01

    LiOH·H2O nanoparticles supported on graphene oxide (GO) were facilely synthesized by a hydrothermal process. The mean diameter of nanoparticles on the integrated graphene sheet was about 5-10 nm showed by SEM and TEM results. XRD results suggested that the nanoparticles are in good agreement with the data of LiOH·H2O. The as-prepared sample showed a greatly enhanced thermal energy storage density and exhibit higher rate of heat release than pure lithium hydroxide, and thermal conductivity of composites increased due to the introduction of nano carbon. LiOH·H2O/GO nanocomposites are novel chemical heat storage materials for potential highly efficient energy system.

  11. 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.

  12. Energy and exergy analysis of particle dispersed latent heat storage system

    Directory of Open Access Journals (Sweden)

    S. Jegadheeswaran, S. D. Pohekar

    2010-05-01

    Full Text Available Latent heat thermal storage (LHTS system has been attractive over the years as an effective energy storage and retrieval device especially in solar thermal applications. However, the performance of LHTS systems is limited by the poor thermal conductivity of phase change materials (PCMs employed. A numerical study is carried out to investigate the performance enhancement of a LHTS unit of shell and tube configuration due to the dispersion of high conductivity particles in the PCM during charging process (melting. Temperature based governing equations have been formulated and solved numerically following an alternate iteration between the temperature and thermal resistance. Exergy based performance evaluation is taken as a main aspect. The numerical results are presented for several mass flow rates and inlet temperatures of heat transfer fluid (HTF. The results indicate a significant improvement in the performance of the LHTS unit when high conductivity particles are dispersed.

  13. 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......) – of the TES unit influences the savings. For this purpose, a reference price signal was used. Results show that it is possible to save up to approximately 14% of the electricity costs. In general, savings increase with Pmax and Emax. However, the benefit of increasing these two values ceases when certain...

  14. 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

    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......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...

  15. Numerical Solution of Heat Transfer Process in PCM Storage Using Tau Method

    Directory of Open Access Journals (Sweden)

    B. Heydari

    2015-01-01

    Full Text Available Thermal energy storage units that utilize phase change materials have been widely employed to balance temporary temperature alternations and store energy in many engineering systems. In the present paper, an operational approach is proposed to the Tau method with standard polynomial bases to simulate the phase change problems in latent heat thermal storage systems, that is, the two-dimensional solidification process in rectangular finned storage with a constant end-wall temperature. In order to illustrate the efficiency and accuracy of the present method, the solid-liquid interface location and the temperature distribution of the fin for three test cases with different geometries are obtained and compared to simplified analytical results in the published literature. The results indicate that using a two-dimensional numerical approach can predict the solid-liquid interface location more accurately than the simplified analytical model in all cases, especially at the corners.

  16. 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)

  17. Numerical Investigation of Stratified Thermal Storage Tank Applied in Adsorption Heat Pump Cycle

    OpenAIRE

    Taheri, Hadi

    2014-01-01

    With the aid of the TES (Thermal Energy Storage) in the adsorption heat pump cycle, the COP of the system can be improved. Different geometrical variations of the TES with stratification device, have been investigated numerically. Furthermore,The effective thermal conductivity has been analyzed. The simulation results of a reference CFD model have been compared with experimental results. Additionally, the porous medium impact on the mixing process and turbulence has been studied numerically.

  18. Heat transfer enhancement in energy storage in spherical capsules filled with paraffin wax and metal beads

    Energy Technology Data Exchange (ETDEWEB)

    Ettouney, Hisham; Alatiqi, Imad; Al-Sahali, Mohammad; Al-Hajirie, Khalida [Kuwait University, Safat (Kuwait). College of Engineering and Petroleum, Department of Chemical Engineering

    2006-01-15

    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. (author)

  19. 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.

  20. Numerical simulations of the impact of seasonal heat storage on source zone emission in a TCE contaminated aquifer

    Science.gov (United States)

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

    2016-04-01

    In urban regions, with high population densities and heat demand, seasonal high temperature heat storage in the shallow subsurface represents an attractive and efficient option for a sustainable heat supply. In fact, the major fraction of energy consumed in German households is used for room heating and hot water production. Especially in urbanized areas, however, the installation of high temperature heat storage systems is currently restricted due to concerns on negative influences on groundwater quality caused e.g. by possible interactions between heat storages and subsurface contaminants, which are a common problem in the urban subsurface. Detailed studies on the overall impact of the operation of high temperature heat storages on groundwater quality are scarce. Therefore, this work investigates possible interactions between groundwater temperature changes induced by heat storage via borehole heat exchangers and subsurface contaminations by numerical scenario analysis. For the simulation of non-isothermal groundwater flow, and reactive transport processes the OpenGeoSys code is used. A 2D horizontal cross section of a shallow groundwater aquifer is assumed in the simulated scenario, consisting of a sandy sediment typical for Northern Germany. Within the aquifer a residual trichloroethene (TCE) contaminant source zone is present. Temperature changes are induced by a seasonal heat storage placed within the aquifer with scenarios of maximum temperatures of 20°C, 40°C and 60°C, respectively, during heat injection and minimum temperatures of 2°C during heat extraction. In the scenario analysis also the location of the heat storage relative to the TCE source zone and plume was modified. Simulations were performed in a homogeneous aquifer as well as in a set of heterogeneous aquifers with hydraulic conductivity as spatially correlated random fields. In both cases, results show that the temperature increase in the heat plume and the consequential reduction of water

  1. 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.

  2. Thermal performance of a heat storage module using PCM's with different melting temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Farid, M.M.; Kanzawa, A.

    1989-05-01

    The performance of a heat storage unit consisting of number of vertical cylindrical capsules filled with phase change materials, with air flowing across them for heat exchange has been analyzed. Earlier theoretical models did not consider temperature distribution in the radial direction within the capsules, an assumption that limits their applications for small diameter capsules. The mathematical model developed in this work is based on solving the heat conduction equation in both melt and solid phases in cylindrical coordinates, taking into account the radial temperature distribution in both phases. Heat flux was then evaluated at the surface of the first row of the capsules to determine the temperature of the air leaving that row by a simple heat balance. It was found that such computation may be carried out for every few rows rather than for a single row to minimize computer time. The simulation study showed a significant improvement in the rate of heat transfer during heat charge and discharge when phase change materials with different melting temperatures were used.

  3. Numerical Study on the Thermal Performance of a Shell and Tube Phase Change Heat Storage Unit during Melting Process

    Directory of Open Access Journals (Sweden)

    Wei Li

    2014-11-01

    Full Text Available This work presents a numerical study of the thermal performance in a shell and tube phase change heat storage unit. Paraffin wax as phase change material (PCM is filled in the shell space. The heat transfer fluids (HTFs: air and water flow through the tube and transfer the heat to PCM. A mathematical model involving HTF and PCM is developed to analyze the thermal performance of the phase change heat storage unit and is validated with experimental data. Numerical investigation is conducted to evaluate the effect of HTF inlet velocity on the HTF outlet temperature, Nu, and melt fraction when air or water is used as HTF. Results indicate that the air inlet velocity has a great effect on the air outlet temperature and heat transfer rate, and the water inlet velocity has little effect on the water outlet temperature. The investigated results can provide a reference for designing phase change heat storage system.

  4. 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.

  5. 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.

  6. Experimental analysis of the performance of optimized fin structures in a latent heat energy storage test rig

    Science.gov (United States)

    Johnson, Maike; Hübner, Stefan; Reichmann, Carsten; Schönberger, Manfred; Fiß, Michael

    2017-06-01

    Energy storage systems are a key technology for developing a more sustainable energy supply system and lowering overall CO2 emissions. Among the variety of storage technologies, high temperature phase change material (PCM) storage is a promising option with a wide range of applications. PCM storages using an extended finned tube storage concept have been designed and techno-economically optimized for solar thermal power plant operations. These finned tube components were experimentally tested in order to validate the optimized design and simulation models used. Analysis of the charging and discharging characteristics of the storage at the pilot scale gives insight into the heat distribution both axially as well as radially in the storage material, thereby allowing for a realistic validation of the design. The design was optimized for discharging of the storage, as this is the more critical operation mode in power plant applications. The data show good agreement between the model and the experiments for discharging.

  7. First supermarket with heat and cold storage; Eerste supermarkt met warmte/koudeopslag

    Energy Technology Data Exchange (ETDEWEB)

    Cuiper, N.

    2008-04-15

    A short overview is provided of the energy saving measures that were taken by a supermarket in Almere, the Netherlands. This supermarket is the first in the Netherlands to make use of heat and cold storage. Heat from the soil is feeding the underfloor heating. Moreover, extra insulation measures, energy efficient tubular lighting and sliding doors and sliding windows are covering cooling and freezing equipment. [mk]. [Dutch] Een kort overzicht wordt gegeven van de maatregelen die zijn genomen voor een supermarkt in Almere, Nederland, om energie te besparen. De supermarkt is de eerste in Nederland die gebruik maakt van de opslag van warmte en koude. Warmte uit de bodem voedt de vloerverwarming. Daarnaast wordt gebruik gemaakt van extra isolatie, energiezuinige TL-buizen en schuifdeuren en schuiframen die de koel- en diepvriesmeubelen afsluiten.

  8. Computational modeling of latent-heat-storage in PCM modified interior plaster

    Science.gov (United States)

    Fořt, Jan; Maděra, Jiří; Trník, Anton; Pavlíková, Milena; Pavlík, Zbyšek

    2016-06-01

    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.

  9. 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.

  10. Thermochemical seasonal solar heat storage with MgCl2.6H2O. First upscaling of the reactor

    Energy Technology Data Exchange (ETDEWEB)

    Zondag, H.A. [Eindhoven University of Technology, Eindhoven (Netherlands); Kikkert, B.W.J.; Smeding, S.; Bakker, M. [ECN Solar Energy, Petten (Netherlands)

    2011-06-15

    In the summer, the available of solar heat exceeds the total heat demand of a building, but in the winter the heat demand is exceeding the solar supply. For the future conversion of a passive house into an energy neutral house, a solution is to store the excess of solar energy in summer, and to use it to meet the heat demand in winter. Water is traditionally used for storing heat (e.g. solar boiler), but seasonal heat storage requires large water tanks (>40m{sup 3}) that are too large to be placed inside an average family house. An alternative option is to store heat by means of chemical processes using the reversible reaction: A + B <-> C + heat. Such thermochemical heat storage has a 5 to 10 times higher energy storage density than water, with the additional benefit that, after charging, the heat can be stored for a long time without losses. With thermochemical materials, the entire heating demand of a low-energy house during winter could be met using a storage volume of 4 to 8 m3, that is charged during summer by solar collectors. Because of the large amount of thermochemical material required for such storages, as well as the strict safety regulations in the built environment, safety and cost of the materials are important aspects. Because of safety criteria, the focus in the present research is on water as the sorbate. Because of low cost and high storage density, the focus is on salt hydrates, rather than silicagel or zeolites. In this paper, R and D on system aspects, materials selection and characterization, as well as on reactor concepts is presented.

  11. 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.

  12. Heat storage containers filled with the combination of a eutectic salt and a non-biodegradable filler material

    Energy Technology Data Exchange (ETDEWEB)

    Schoenfelder, J.L.

    1980-09-23

    A heat storage article adapted for prevention of stratification of heat storage materials, such as eutectic salts contained within the container element. The article is comprised of a heavy thermally conductive container with an internal cavity. The internal cavity of the container is substantially completely filled with a combination of a non-biodegradable filler material such as glass fiber insulation and a eutectic salt.

  13. 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

  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. Building-Integrated Photovoltaics (BIPV): Analysis and US market potential

    Science.gov (United States)

    Frantzis, Lisa; Friedman, David; Hill, Sarah; Teagan, Peter; Strong, Steven; Strong, Marilyn

    1995-02-01

    Arthur D. Little, Inc., in conjunction with Solar Design Associates, conducted a study for the US Department of Energy (DOE), Office of Building Technologies (OBT) to determine the market potential for grid-connected, building-integrated photovoltaics (BIPV). This study defines BIPV as two types of applications: (1) where the PV modules are an integral part of the building, often serving as the exterior weathering skin; and (2) the PV modules are mounted on the existing building exterior. Both of these systems are fully integrated with the energy usage of the building and have potential for significant market penetration in the US. Off-grid building applications also offer a near-term market for BIPV, but are not included in the scope of this study.

  16. 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.)

  17. 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.

  18. Experience with building integrated solar collectors; Erfaring med bygningsintegrerte solfangere

    Energy Technology Data Exchange (ETDEWEB)

    Simonsen, Ingeborg; Time, Berit; Andresen, Inger

    2011-07-01

    The main objective of the research 'Zero Emission Buildings' ZEB is to develop products and solutions that provide buildings with zero greenhouse gas emissions associated with the production, operation and disposal. Can we make this happen must the building produce more energy than it needs to compensate for greenhouse gas emissions from the production of materials and the actual construction.To build up knowledge on experience with building integrated solar collectors in Norway, we have in this study made interviews with suppliers and manufacturers of solar collectors and some building owners. Since the focus is on climate shell, we have limited the study to include solar collectors to replace a part of the cladding or roofing. Construction upstairs roofing, outside facade or freestanding rack is not considered as building integrated in this context. The providers we have been in contact with appeals to slightly different parts of the market. This is reflected in the product's development, assembly and approach to the calculation of energy delivery. Overall, providers may offer a range of products suitable for both the professional and skilled carpenter, the interested 'man in the street' . The feedback we have received shows generally good experiences with the product and the installation. Because of the preliminary short operating periods of the investigated plants we have little data on energy supply from these plants. In summary, we can say that the knowledge and the products are available and it is up to use to use them.(Author)

  19. Novel metallic alloys as phase change materials for heat storage in direct steam generation applications

    Science.gov (United States)

    Nieto-Maestre, J.; Iparraguirre-Torres, I.; Velasco, Z. Amondarain; Kaltzakorta, I.; Zubieta, M. Merchan

    2016-05-01

    Concentrating Solar Power (CSP) is one of the key electricity production renewable energy technologies with a clear distinguishing advantage: the possibility to store the heat generated during the sunny periods, turning it into a dispatchable technology. Current CSP Plants use an intermediate Heat Transfer Fluid (HTF), thermal oil or inorganic salt, to transfer heat from the Solar Field (SF) either to the heat exchanger (HX) unit to produce high pressure steam that can be leaded to a turbine for electricity production, or to the Thermal Energy Storage (TES) system. In recent years, a novel CSP technology is attracting great interest: Direct Steam Generation (DSG). The direct use of water/steam as HTF would lead to lower investment costs for CSP Plants by the suppression of the HX unit. Moreover, water is more environmentally friendly than thermal oils or salts, not flammable and compatible with container materials (pipes, tanks). However, this technology also has some important challenges, being one of the major the need for optimized TES systems. In DSG, from the exergy point of view, optimized TES systems based on two sensible heat TES systems (for preheating of water and superheating vapour) and a latent heat TES system for the evaporation of water (around the 70% of energy) is the preferred solution. This concept has been extensively tested [1, 2, 3] using mainly NaNO3 as latent heat storage medium. Its interesting melting temperature (Tm) of 306°C, considering a driving temperature difference of 10°C, means TES charging steam conditions of 107 bar at 316°C and discharging conditions of 81bar at 296°C. The average value for the heat of fusion (ΔHf) of NaNO3 from literature data is 178 J/g [4]. The main disadvantage of inorganic salts is their very low thermal conductivity (0.5 W/m.K) requiring sophisticated heat exchanging designs. The use of high thermal conductivity eutectic metal alloys has been recently proposed [5, 6, 7] as a feasible alternative. Tms

  20. 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.

  1. Magnesium alloy-graphite composites with tailored heat conduction properties for hydrogen storage applications

    Energy Technology Data Exchange (ETDEWEB)

    Pohlmann, Carsten; Kalinichenka, Siarhei [Institute for Materials Science, Dresden University of Technology, Helmholtzstr. 7, 01069 Dresden (Germany); Roentzsch, Lars; Hutsch, Thomas [Fraunhofer Institute for Manufacturing Technology and Applied Materials Research, Winterbergstr. 28, 01277 Dresden (Germany); Kieback, Bernd [Institute for Materials Science, Dresden University of Technology, Helmholtzstr. 7, 01069 Dresden (Germany); Fraunhofer Institute for Manufacturing Technology and Applied Materials Research, Winterbergstr. 28, 01277 Dresden (Germany)

    2010-12-15

    Melt-spun magnesium alloys that contain catalytically active constituents have become attractive hydrogen storage materials due to their ultra-fine and homogeneous microstructure and their excellent (de-)hydrogenation characteristics. However, their heat conduction properties have to be improved for practical applications. For this purpose, composites of melt-spun magnesium alloys and expanded natural graphite (ENG) were examined in this work. Melt-spun flakes were mixed with different amounts of up to 25.5 wt.% ENG. These mixtures were compacted to cylindrical pellets using compaction pressures up to 600 MPa. For comparison, pellets of pure magnesium hydride and ENG were equally processed. All sets of specimens were investigated regarding their thermal conductivities in radial and axial direction, their microstructure and phase fractions. It was found that the heat transfer characteristics can be tailored in a wide range, e.g. the thermal conductivity of magnesium alloy-ENG compacts were tuned from 1 up to 47 W m{sup -1} K{sup -1}. For the system MgH{sub 2}-ENG, the thermal conductivity can be adjusted from 1 up to 43 W m{sup -1} K{sup -1}. Therefore, a hydrogen storage material with homogeneous heat transfer properties can be anticipated which only slightly depend on the hydrogenated fraction. (author)

  2. 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.)

  3. Decay heat power of spent nuclear fuel of power reactors with high burnup at long-term storage

    Science.gov (United States)

    Ternovykh, Mikhail; Tikhomirov, Georgy; Saldikov, Ivan; Gerasimov, Alexander

    2017-09-01

    Decay heat power of actinides and fission products from spent nuclear fuel of power VVER-1000 type reactors at long-term storage is calculated. Two modes of storage are considered: mode in which single portion of actinides or fission products is loaded in storage facility, and mode in which actinides or fission products from spent fuel of one VVER reactor are added every year in storage facility during 30 years and then accumulated nuclides are stored without addition new nuclides. Two values of fuel burnup 40 and 70 MW·d/kg are considered for the mode of storage of single fuel unloading. For the mode of accumulation of spent fuel with subsequent storage, one value of burnup of 70 MW·d/kg is considered. Very long time of storage 105 years accepted in calculations allows to simulate final geological disposal of radioactive wastes. Heat power of fission products decreases quickly after 50-100 years of storage. The power of actinides decreases very slow. In passing from 40 to 70 MW·d/kg, power of actinides increases due to accumulation of higher fraction of 244Cm. These data are important in the back end of fuel cycle when improved cooling system of the storage facility will be required along with stronger radiation protection during storage, transportation and processing.

  4. 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.

  5. First and Second Laws Analyses of a Closed Latent Heat Thermal Energy Storage System

    Institute of Scientific and Technical Information of China (English)

    A.SARI; K.KAYGUSUZ

    2004-01-01

    First and Second Law analyses were conducted to evaluate the performance of a closed latent heat thermal energy storage (LHTES) system employing calcium chloride hexahydrate (CaCl2-6H2O).The First and the Second Laws of thermodynamics were applied to the system from viewpoint of energy and exergy analyses,respectively. The energy storage tank in the system is neither fully mixed nor fully stratified. It may be considered as semithermal stratified. Experiments that include both charging and discharging periods were performed on sunny winter days in 1996. The energy and exergy variations and the overall energy and exergy efficiencies of the closed LHTES system were calculated for the complete charging and discharging cycle of the selected fifteen clear-sky winter days. Mean energy and exergy efficiencies were found to be 55.20% and 34.83%, respectively.

  6. Numerical analysis of latent heat storage system with encapsulated phase change material in spherical capsules

    Directory of Open Access Journals (Sweden)

    Bellan Selvan

    2017-01-01

    Full Text Available Solar energy has been considered as one of the promising solutions to replace the fossil fuels. To generate electricity beyond normal daylight hours, thermal energy storage systems (TES play a vital role in concentrated solar power (CSP plants. Thus, a significant focus has been given on the improvement of TES systems from the past few decades. In this study, a numerical model is developed to obtain the detailed heat transfer characteristics of lab-scale latent thermal energy storage system, which consists of molten salt encapsulated spherical capsules and air. The melting process and the corresponding temperature and velocity distributions in every capsule of the system are predicted. The enthalpy-porosity approach is used to model the phase change region. The model is validated with the reported experimental results. Influence of initial condition on the thermal performance of the TES system is predicted.

  7. Solar assisted absorption or motor driven heat pump with earth seasonal storage: Part 2, Tables and figures: Final report

    Energy Technology Data Exchange (ETDEWEB)

    Lazzarin, R.M.

    1986-01-01

    A plant composed of an energy roof, a seasonal earth storage and an absorption heat pump has been tested. The purpose was to study the behavior of the various components and their interaction. The surveys went on during two years. The following operations are considered: the charging of the earth storage by the energy roof and the working of an absorption heat pump connected either to the energy roof or to the earth storage. This volume contains all the figures and tables for the report. 77 figs., 24 tabs.

  8. Materials compatibility in Dish-Stirling solar generators using Cu-Si-Mg eutectic for latent heat storage

    Science.gov (United States)

    Kruizenga, A. M.; Withey, E. A.; Andraka, C. E.; Gibbs, P. J.

    2016-05-01

    Dish-Stirling systems are a strong candidate to meet cost production goals for solar thermal power production. Thermal energy storage improves the capacity factor of thermal power systems; copper-silicon-magnesium eutectic alloys have been investigated as potential latent heat storage materials. This work examines the ability of commercially available plasma spray coatings to serve as protective barriers with these alloys, while highlighting mechanistic insights into materials for latent heat storage systems. Computed tomography was leveraged as a rapid screening tool to assess the presence of localized attack in tested coatings.

  9. Research Progress on Thermochemical Heat Storage System%热化学蓄热系统研究进展

    Institute of Scientific and Technical Information of China (English)

    王智辉; 漥田光宏; 杨希贤; 刘学成; 何兆红; 大坂侑吾; 黄宏宇

    2015-01-01

    热化学蓄热通过可逆化学反应来储存和释放热量,其蓄热密度高于显热蓄热和相变蓄热,且能够实现能量的长期储存,在未来能源利用领域具有广阔前景.根据热化学蓄热系统的结构,可将其分为开式系统和闭式系统.本文针对开式系统和闭式系统,对蓄热材料、环境气氛条件、反应过程优化以及反应器设计等影响系统性能的重要因素进行概述与讨论,为热化学蓄热系统的发展和实际应用提供参考.%Thermochemical heat storage technology can store and discharge heat energy by reversible chemical reactions. It shows higher heat storage density and better long-term preservation ability than sensible heat storage and phase change heat storage, so that have a bright future in the energy application fields. According to the system configuration, thermochemical heat storage system is suggested to be divided into open and closed system. In terms of open and closed system, the crucial factors impacting on the system performance, such as heat storage materials, ambient atmosphere conditions, reaction progress optimization and reactor design, are discussed and summarized to provide some references for the development and practical applications of thermochemical heat storage system.

  10. Transient Thermal Behavior of a Vertical Solar Storage Tank with a Mantle Heat Exchanger During No-Flow Operation

    Directory of Open Access Journals (Sweden)

    A. Barzegar

    2009-01-01

    Full Text Available Transient thermal behavior of a vertical storage tank of a domestic solar heating system with a mantle heat exchanger has been investigated numerically in the charging mode. It is assumed that the tank is initially filled with uniform cold water. At an instant of time, the hot fluid from collector outlet is uniformly injected in the upper section of the mantle heat exchanger and after heat transfer with the fluid inside the tank, withdrawn from the bottom part of the heat exchanger. The conservation equations in the cylindrical coordinate and in axis-symmetric condition have been used according to the geometry under investigation. Governing equations have been discretized by employing the finite volume method and the SIMPLER algorithm has been used for coupling between momentum and pressure equations. The Low Reynolds Number (LRN k −ω model is utilized for treating turbulence in the fluid. First, the transient thermal behavior of heat storage tank and the process of formation of thermal stratification in the heat storage tank were investigated. Then, the influence of Rayleigh number in the heat storage tank, Reynolds number in the mantle heat exchanger and vertical positioning of mantle on the flow and thermal fields and the formation of the thermal stratification was investigated. It is found that for higher values of Rayleigh number, a more suitable thermal stratification is established inside the tank. Also it is noticed that increasing the incoming fluid velocity through the mantle heat exchanger causes a faster formation of the thermal stratification. A superior thermal performance was achieved when the mantle heat exchanger is positioned at the middle height of the storage tank.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1984-05-01

    Solar thermal energy storage systems can be categorized based on materials that store either as sensible heat or as latent heat of fusion. For convenience, the latter are designated as phase change materials (PCM). It is a fairly well accepted fact that PCM storage devices usually require less storage volume. In a recent paper, heat exchanger effectiveness for PCM storage units was theoretically derived and presented in chart form. The heat exchanger considered was a shell-and-tube type, viz., the shell side filled with PCM and the tube side with heating or cooling fluid. The PCM heat storage system presented here, however, involves both heating and cooling fluids with a PCM in the middle composed of rectangular channels. This system may be used to store the thermal energy absorbed by a solar collector for the purpose of heating a building. The thermal energy carried by a hot fluid coming from the solar collector can be transferred through the upper surface I. The thermal energy stored in the system can be extracted through the lower surface II by a cold fluid circulating through the building. In order to transfer heat to the melting PCM, the temperature of the hot fluid must be higher than the melting point of the PCM, T /SUB m/ , and to remove heat from the solidifying PCM, the temperature of the cold fluid must be lower than T /SUB m/ . Therefore, the melting point of the PCM presents a limitation of the temperature of both the hot and cold fluids. This temperature limitation is more or less similar to the temperature restriction of a parallel-flow heat exchanger, in which the final temperature of the cold fluid can never reach the outlet temperature of the hot fluid.

  12. Thermochemical storage for CSP via redox structured reactors/heat exchangers: The RESTRUCTURE project

    Science.gov (United States)

    Karagiannakis, George; Pagkoura, Chrysoula; Konstandopoulos, Athanasios G.; Tescari, Stefania; Singh, Abhishek; Roeb, Martin; Lange, Matthias; Marcher, Johnny; Jové, Aleix; Prieto, Cristina; Rattenbury, Michael; Chasiotis, Andreas

    2017-06-01

    The present work provides an overview of activities performed in the framework of the EU-funded collaborative project RESTRUCTURE, the main goal of which was to develop and validate a compact structured reactor/heat exchanger for thermochemical storage driven by 2-step high temperature redox metal oxide cycles. The starting point of development path included redox materials qualification via both theoretical and lab-scale experimental studies. Most favorable compositions were cobalt oxide/alumina composites. Preparation of small-scale structured bodies included various approaches, ranging from perforated pellets to more sophisticated honeycomb geometries, fabricated by extrusion and coating. Proof-of-concept of the proposed novel reactor/heat exchanger was successfully validated in small-scale structures and the next step included scaling up of redox honeycombs production. Significant challenges were identified for the case of extruded full-size bodies and the final qualified approach related to preparation of cordierite substrates coated with cobalt oxide. The successful experimental evaluation of the pilot reactor/heat exchanger system constructed motivated the preliminary techno-economic evaluation of the proposed novel thermochemical energy storage concept. Taking into account experimental results, available technologies and standard design aspects a model for a 70.5 MWe CSP plant was defined. Estimated LCOE costs were calculated to be in the range of reference values for Combined Cycle Power Plants operated by natural gas. One of main cost contributors was the storage system itself, partially due to relatively high cost of cobalt oxide. This highlighted the need to identify less costly and equally efficient to cobalt oxide redox materials.

  13. 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...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1991-10-01

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

  15. Heat release characteristics of middle temperature latent heat storage vessel by means of direct contact heat exchange method; Chokusetsu sesshoku netsu kokanho wo mochiita chuondo sennetsu chikunetsuso no honetsu tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Inaba, H.; Horibe, A.; Ozaki, K. [Okayama University, Okayama (Japan). Faculty of Engineering; Emoto, K. [Okayama University, Okayama (Japan); Kakiuchi, H. [Mitsubishi Chemical Corp., Tokyo (Japan)

    1999-07-25

    Experiment has been performed of heat transfer characteristics of the middle temperature latent heat storage system of the direct-contact heat transfer by using m-E (meso-Erythritol, melting point of 119 degree C, latent heat of 375 kJ/kg) droplets as a latent heat storage material and silicone oil as a heat transfer medium. In the present study the liquid m-E was injected into the heat transfer medium through a circular nozzle. The m-E droplets changed from liquid to solid phase during falling in the heat transfer medium at low temperature. From the measuring results of m-E droplet diameter, falling velocity, and solidification rate, the nondimensional empirical equations of the arithmetic mean diameter of the droplets and falling velocity, the solidification rate and the overall heat transfer coefficient were derived as a function of the characteristic arithmetic mean diameter, the terminal velocity, temperature and physical properties. (author)

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

    Science.gov (United States)

    Namkoong, D.

    1976-01-01

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

  17. Active-flow components with latent heat storage; Aktiv durchstroemte Bauteile mit Latentwaermespeicher

    Energy Technology Data Exchange (ETDEWEB)

    Haussmann, T. [PSE GmbH - Forschung, Entwicklung, Marketing, Freiburg (Germany); Schossig, P.; Henning, H.M.; Rogg, H. [Fraunhofer-Institut fuer Solare Energiesysteme ISE, Freiburg (Germany)

    2005-07-01

    In a BMWA-funded project terminated in September 2004, new construction materials with integrated latent heat storage were developed by Fraunhofer ISE and the industrial partners BASF, maxit, DAW, and Sto. The focus was on phase change materials for passive cooling of buildings. In addition to 'Micronal' by BASF, two new materials were presented at Otti Symposium Thermische Solarenergie Nr. 13 and 14. One of these is available on the market since the end of 2004 under the name of 'maxit clima'. The current project now focused on active-flow systems. (orig.)

  18. Laboratory Evaluation of Gas-Fired Tankless and Storage Water Heater Approaches to Combination Water and Space Heating

    Energy Technology Data Exchange (ETDEWEB)

    Kingston, T. [Gas Technology Inst., Des Plaines, IL (United States); Scott, S. [Gas Technology Inst., Des Plaines, IL (United States)

    2013-03-01

    Homebuilders are exploring more cost-effective combined space and water heating systems (combo systems) with major water heater manufacturers that are offering pre-engineered forced air space heating combo systems. In this project, unlike standardized tests, laboratory tests were conducted that subjected condensing tankless and storage water heater based combo systems to realistic, coincidental space and domestic hot water loads and found that the tankless combo system maintained more stable DHW and space heating temperatures than the storage combo system, among other key findings.

  19. Effect of roughness geometry on heat transfer and friction characteristics of PCM storage unit for night coolness storage in summer season

    Directory of Open Access Journals (Sweden)

    Shukla Shailndra Kumar

    2013-01-01

    Full Text Available This paper presents a theoretical analysis of thermal storage unit using phase change material (PCM as storage medium. Storage unit consists of parallel rectangular channels for the air flow which are separated by phase change storage material. The purpose of storage unit is to absorb the night coolness and to provide cooled air at comfort temperature during day time in summer season. MATLsimulation tool has been used to compute the air temperature variation with location as well as time, charging and discharging time of storage unit. Phase change material used for analysis is selected in such a way that it’s Melting point lies between comfort temperature and minimum night ambient temperatures. The air flow rate needed for charging of PCM is approximately four times greater than the flow rate required during day time to achieve comfort temperature for approximately eight hours, due to limited summer night time (only eight hours. The length of storage unit for which NTU value is greater than or equal to five will give the exit air temperature equal to PCM temperature for the case of latent heat utilization. It is found that artificial roughness on the duct surface effectively reduces the length of storage unit in the cost of some extra pressure drop across the duct.

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

    Science.gov (United States)

    Trebilcox, G. J.; Lundberg, W. L.

    1981-03-01

    The canning segment of the food processing industry is a major energy user within that industry. Most of its energy demand is met by hot water and steam and those fluids, in addition to product cooling water, eventually flow from the processes as warm waste water. To minimize the possibility of product contamination, a large percentage of that waste water is sent directly to factory drains and sewer systems without being recycled and in many cases the thermal energy contained by the waste streams also goes unreclaimed and is lost from further use. Waste heat recovery in canning facilities can be performed economically using systems that employ thermal energy storage (TES). A project was proposed in which a demonstration waste heat recovery system, including a TES feature, would be designed, installed and operated.

  1. 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

    the performance of the new deck with PCM concrete is the thermal properties of such a new material, as the PCM concrete is yet to be well defined. The results presented in the paper include models in which the PCM concrete material properties, such as thermal conductivity, and specific heat capacity were first......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...... with and without microencapsulated PCM are presented. The new concrete deck with microencapsulated PCM is the standard deck on which an additional layer of the PCM concrete was added and, at the same time, the latent heat storage was introduced to the construction. The challenge of numerically simulating...

  2. Transparent insulation facade element with integrated latent heat storage and solar shading; TWD-Fassadenelement mit integriertem Latentspeicher und Sonnenschutz

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, D. [Architekturbuero Dietrich Schwarz, Domat/Ems (Switzerland); Nussbaumer, T. [Verenum, Zuerich (Switzerland)

    2001-07-01

    This yearly report for the Swiss Federal Office of Energy (SFOE) describes a facade element using transparent insulation and integrated latent-heat storage that was used in the construction of a house in the Toggenburg region of Switzerland. The principles of the latent-heat storage system are discussed and the architecture of the house, which is built to 'zero-energy' standards is described. Also, its energy supply, which includes a small heat pump, is described. The results of measurement campaigns on the performance of the transparent insulation system and its latent heat storage made both in the Swiss Federal Laboratories for Materials Testing and Research and in the house itself are presented and discussed. Overheating protection in summer is discussed and the experience gained from tests made with prismatic glass panes and standard solar-protection glass is discussed. Also, user behaviour and the automatic and manual operation of the control systems are looked at.

  3. Heat storage in gypsum. Final report to the Energy Agency; Vaermelagring i Gips. Slutrapport foer Energimyndigheten

    Energy Technology Data Exchange (ETDEWEB)

    Chaudhuri, Punya (Process Improvements, Plankgatan 26, Norrkoeping (Sweden)); Kindh, Torgny (Environnet AB, Norrkoeping (Sweden)); Lawrence, David; Wahlstroem, Krister (Dept. of Physics, Chemistry and Biology, Linkoeping Univ., Linkoeping (Sweden))

    2007-06-15

    The Swedish Energy Agency's project 'energy storage in gypsum', began in April 2007 and finished a year later. The objective was to demonstrate the potential of using gypsum to store and retrieve low-grade heat at a pilot scale (i.e. using 200 kg of gypsum). Gypsum undergoes a reversible reaction with water in which it stores or releases energy. Preliminary work indicated that when using commercially available gypsum powder, a packed bed would not allow sufficient mass or heat transfer. Preliminary work also revealed that simple fluidization was not possible with the very fine particles: stirred fluidization was the solution used. A pilot-scale unit was constructed (essentially a closed tank about 1 m in diameter and 1 m high). To store energy, hot, dry air is contacted with the gypsum to bring the temperature of the powder to about 110 deg C. Once the powder is 'dried' it is returned to room temperature and isolated from the surroundings - in this state energy is stored indefinitely. To recover the heat, water was atomized, mixed with warm air (to vaporize the water) and reacted with the gypsum. Typically we were able to recover about 6 kWh of energy, which is only about 20% of what is possible. This is partly the result of too little insulation on the reactor and a hesitation to over-hydrate the gypsum (which would result in solid plaster). We anticipate that this will at least double with increased operating experience. Overall gypsum behaves at a pilot scale as was expected; in terms of energy storage for space heating, it shows great promise. Our experiences to date have shown that using gypsum with a larger particle size (to allow simple fluidization) is an important improvement.

  4. 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.

  5. Prediction of thermal hydraulic characteristics inside the storage tank of a horizontal condensation heat exchanger using MARS-KS

    Science.gov (United States)

    Shin, Byung Soo; Seul, Kwang Won; Do, Kyu Sik; Reactor system evaluation Team

    2012-11-01

    The performance of a horizontal condensation heat exchanger is determined by the condensation heat transfer inside the heat exchanger tubes, convective or boiling heat transfer outside the tubes and flow characteristics in the storage tank. The flow characteristics in the tank are important factors to determine the heat transfer rate outside the tubes. The objective of this work is to develop the method to predict the heat transfer rate outside the tubes properly using MARS-KS code. Two different results from MARS-KS were compared with simplified experimental results in other works to estimate the capacity of MARS-KS. One was by a typical 1D nodalization but another was by a 3D nodalization considering natural circulation in the storage tank. Then, to eliminate the effect of condensation heat transfer inside the tubes, the experimental results on temperature profiles were applied to the inside wall of tubes as boundary conditions. As the result, the 3-D nodalization model had good predictions with experimental results in regard of wall temperature, heat flux and heat transfer coefficients. It was also confirmed that the natural circulation flow was developed inside the storage tank.

  6. Thermal Analysis of a Thermal Energy Storage Unit to Enhance a Workshop Heating System Driven by Industrial Residual Water

    Directory of Open Access Journals (Sweden)

    Wenqiang Sun

    2017-02-01

    Full Text Available Various energy sources can be used for room heating, among which waste heat utilization has significantly improved in recent years. However, the majority of applicable waste heat resources are high-grade or stable thermal energy, while the low-grade or unstable waste heat resources, especially low-temperature industrial residual water (IRW, are insufficiently used. A thermal energy storage (TES unit with paraffin wax as a phase change material (PCM is designed to solve this problem in a pharmaceutical plant. The mathematical models are developed to simulate the heat storage and release processes of the TES unit. The crucial parameters in the recurrence formulae are determined: the phase change temperature range of the paraffin wax used is 47 to 56 °C, and the latent heat is 171.4 kJ/kg. Several thermal behaviors, such as the changes of melting radius, solidification radius, and fluid temperature, are simulated. In addition, the amount of heat transferred, the heat transfer rate, and the heat storage efficiency are discussed. It is presented that the medicine production unit could save 10.25% of energy consumption in the investigated application.

  7. CALCULATION OF INTERNAL THERMAL RESISTANCE OF WORKING BODIES OF PACKEDBED SENSIBLE AND LATENT HEAT STORAGES

    Directory of Open Access Journals (Sweden)

    Ermuratschii V.V.

    2013-12-01

    Full Text Available The paper considers the problem of calculating values of the internal thermal resistance of a packed bed sensible and latent heat storages working bodies. The methodic calculation of this resistance for bodies with solid, liquid substance and phase-change materials is offered. Being based on the theory of a regular thermal mode, formulas for calculation of internal thermal resistance of the bodies having the form of a sphere, the cylinder and a paralle-lepiped are obtained. For bodies with liquid substance this resistance is in view of a wall of vessels and resistance of a boundary layer at natural convection of liquids. In the case of substances with a phase transition heat resistance zones with different states of aggregation shall be determined separately. Electro-thermal model contains of the four thermal resistances, two heat capacity and single voltage source. Internal thermal resistance of solids can be considered as a constant parameter. For bodies of liquid and phase change material internal thermal resistance depends on their thermal state. Therefore, these values should be determined in the calculation processes of their heating or cooling.

  8. Self-pressurization of a flightweight liquid hydrogen storage tank subjected to low heat flux

    Science.gov (United States)

    Hasan, M. M.; Lin, C. S.; Vandresar, N. T.

    1991-01-01

    Results are presented for an experimental investigation of self-pressurization and thermal stratification of a 4.89 cu m liquid hydrogen (LH2) storage tank subjected to low heat flux (0.35, 2.0, and 3.5 W/sq m) under normal gravity conditions. Tests were performed at fill levels of 83 to 84 percent (by volume). The LH2 tank was representative of future spacecraft tankage, having a low mass-to-volume ratio and high performance multilayer thermal insulation. Results show that the pressure rise rate and thermal stratification increase with increasing heat flux. At the lowest heat flux, the pressure rise rate is comparable to the homogenous rate, while at the highest heat flux, the rate is more than three times the homogeneous rate. It was found that initial conditions have a significant impact on the initial pressure rise rate. The quasi-steady pressure rise rates are nearly independent of the initial condition after an initial transient period has passed.

  9. Microencapsulated PCM slurries for heat transfer and energy storage in spacecraft systems

    Science.gov (United States)

    Colvin, David P.; Mulligan, James C.; Bryant, Yvonne G.; Duncan, John L.; Gravely, Benjamin T.

    The technical feasibility for providing significantly enhanced heat transport and storage as well as improved thermal control has been investigated during several Small Business Innovative Research (SBIR) programs for NASA, the United States Air Force (USAF), and the Strategic Defense Initiative Organization (SDIO) using microencapsulated phase change materials (PCMs) in both aqueous and nonaqueous two-component slurries. In the program for SDIO, novel two-component coolant fluids were prepared and successfully tested at both low (300 K) and intermediate temperatures (460 to 700 K). The two-component fluid slurries of microencapsulated PCMs included organic particles in aqueous and nonaqueous liquids, as well as microencapsulated metals that potentially could be carried by liquid metals or used as powdered heat sinks. Simulation and experimental studies showed that such active cooling systems could be designed and operated with enhancements of heat capacity that exceeded 10 times or 1000 percent that for the base fluid along with significant enhancement in the fluid's heat capacity. Furthermore, this enhancement provided essentially isothermal conditions throughout the pumped primary coolant fluid loop. The results suggest that together with much higher fluid thermal capacity, greater uniformity of temperature is achievable with such fluids, and that significant reductions in pumping power, system size, and system mass are also possible.

  10. Closed loop chemical systems for energy storage and transmission (chemical heat pipe). Final report

    Energy Technology Data Exchange (ETDEWEB)

    Vakil, H.B.; Flock, J.W.

    1978-02-01

    The work documents the anlaysis of closed loop chemical systems for energy storage and transmission, commonly referred to as the Chemical Heat Pipe (CHP). Among the various chemical reaction systems and sources investigated, the two best systems were determined to be the high temperature methane/steam reforming reaction (HTCHP) coupled to a Very High Temperature Gas Cooled Reactor (VHTR) and the lower temperature, cyclohexane dehydrogenation reaction (LTCHP) coupled to existing sources such as coal or light water reactors. Solar and other developing technologies can best be coupled to the LTCHP. The preliminary economic and technical analyses show that both systems could transport heat at an incremental cost of approximately $1.50/GJ/160 km (in excess of the primary heat cost of $2.50/GJ), at system efficiencies above 80%. Solar heat can be transported at an incremental cost of $3/GJ/160 km. The use of the mixed feed evaporator concept developed in this work contributes significantly to reducing the transportation cost and increasing the efficiency of the system. The LTCHP shows the most promise of the two systems if the technical feasibility of the cyclic closed loop chemical reaction system can be established. An experimental program for establishing this feasibility is recommended. Since the VHTR is several years away from commercial demonstration and the HTCHP chemical technology is well developed, future HTCHP programs should be aimed at VHTR and interface problems.

  11. OPTIMIZATION OF INTERNAL HEAT EXCHANGERS FOR HYDROGEN STORAGE TANKS UTILIZING METAL HYDRIDES

    Energy Technology Data Exchange (ETDEWEB)

    Garrison, S.; Tamburello, D.; Hardy, B.; Anton, D.; Gorbounov, M.; Cognale, C.; van Hassel, B.; Mosher, D.

    2011-07-14

    Two detailed, unit-cell models, a transverse fin design and a longitudinal fin design, of a combined hydride bed and heat exchanger are developed in COMSOL{reg_sign} Multiphysics incorporating and accounting for heat transfer and reaction kinetic limitations. MatLab{reg_sign} scripts for autonomous model generation are developed and incorporated into (1) a grid-based and (2) a systematic optimization routine based on the Nelder-Mead downhill simplex method to determine the geometrical parameters that lead to the optimal structure for each fin design that maximizes the hydrogen stored within the hydride. The optimal designs for both the transverse and longitudinal fin designs point toward closely-spaced, small cooling fluid tubes. Under the hydrogen feed conditions studied (50 bar), a 25 times improvement or better in the hydrogen storage kinetics will be required to simultaneously meet the Department of Energy technical targets for gravimetric capacity and fill time. These models and methodology can be rapidly applied to other hydrogen storage materials, such as other metal hydrides or to cryoadsorbents, in future work.

  12. Performance evaluation of solar box cooker assisted with latent heat energy storage system for cooking application

    Science.gov (United States)

    Vigneswaran, V. S.; Kumaresan, G.; Sudhakar, P.; Santosh, R.

    2017-05-01

    Solar cooking is one of the most promising techniques to meet the cooking needs in remote areas where electricity and fuel supplies are meager. Solar box cooker is an efficient device used in solar cooking as it is simple to fabricate, easy to operate and hazard-free. In this context, the performance evaluation of a solar box cooker with varied number of reflectors has been undertaken. It was found that the time consumed for cooking in a box type solar cooker with four reflectors is lesser compared to that of a single reflector and its overall utilization efficiency increases with increase in the cooking mass. Further, a latent heat energy storage system was designed and fabricated to cook the food at off-peak hours of solar radiation. This latent heat energy storage system was combined with the solar box cooker. Oxalic acid dihydrate was used as the phase change material due to its high specific enthalpy and its melting point lying close to the cooking temperature. It was found that the solar box cooker with phase change material could be effectively utilized to cook food during off-peak hours of solar radiation.

  13. Storage stability of lycopene in tomato juice subjected to combined pressure-heat treatments.

    Science.gov (United States)

    Gupta, Rockendra; Balasubramaniam, V M; Schwartz, Steven J; Francis, David M

    2010-07-28

    A study was conducted to characterize the storage stability of lycopene in hot-break tomato juice prepared from two different cultivars and processed by various pressure-heat combinations. Samples were subjected to pressure assisted thermal processing (PATP; 600 MPa, 100 degrees C, 10 min), high pressure processing (HPP; 700 MPa, 45 degrees C, 10 min), and thermal processing (TP; 0.1 MPa, 100 degrees C, 35 min). Processed samples were stored at 4, 25, and 37 degrees C for upto 52 weeks. HPP and PATP treatments significantly improved the extractability of lycopene over TP and control. All-trans lycopene was found to be fairly stable to isomerization during processing, and the cis isomer content of the control and processed juice did not differ significantly. During storage, lycopene degradation varied as a function of the cultivar, processing method, storage temperature, and time. This study shows that combined pressure-temperature treatments could be an attractive alternative to thermal sterilization for preserving tomato juice quality.

  14. 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

    In this paper integration of wind power generation into the Croatian electricity supply is analysed using available technologies. The starting point is a model of the energy system in Croatia in 2007. Comprehensive hour-by-hour energy system analyses are conducted of a complete system meeting...... 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...... 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...

  15. Demonstration of Mg2FeH6 as heat storage material at temperatures up to 550 °C

    Science.gov (United States)

    Urbanczyk, R.; Meggouh, M.; Moury, R.; Peinecke, K.; Peil, S.; Felderhoff, M.

    2016-04-01

    The storage of heat at high temperatures, which can be used to generate electricity after sunset in concentrating solar power plants, is one of the most challenging technologies. The use of metal hydride could be one possibility to solve the problem. During the endothermic heat storage process, the metal hydride is decomposed releasing hydrogen, which then can be stored. During the exothermic reaction of the metal with the hydrogen gas, the stored heat is then released. Previous research had shown that Mg and Fe powders can be used at temperatures up to 550 °C for heat storage and shows excellent cycle stability over hundreds of cycles without any degradation. Here, we describe the results of testing of a tube storage tank that contained 211 g of Mg and Fe powders in 2:1 ratio. Twenty-three dehydrogenations (storage) and 23 hydrogenations (heat release) in the temperature range between of 395 and 515 °C and pressure range between 1.5 and 8.6 MPa were done. During the dehydrogenation, 0.41-0.42 kWhth kg-1 of heat based on material 2 Mg/Fe can be stored in the tank. After testing, mainly Mg2FeH6 was observed and small amounts of MgH2 and Fe metal can be detected in the hydride samples. This means that the heat storage capacity of the system could be further increased if only Mg2FeH6 is produced during subsequent cycles.

  16. EFFECTS OF HEAT TREATMENT AND CALCIUM ON POSTHARVEST STORAGE OF ATEMOYA FRUITS*

    Directory of Open Access Journals (Sweden)

    LIZ MARIA ABI RACHED TORRES

    2010-03-01

    Full Text Available

    The aim of the present study was to investigate the effect of postharvest warm dipping with calcium chloride (CaCl2 on atemoya fruit (Annona cherimola Mill x Annona squamosa L. storage. Fruits were immersed in 6% CaCl2 solution at 20 and 40°C for 20 min followed by storage at room temperature. The effectiveness of the treatment was assessed in terms of its impact on peel and fl esh appearance, weight loss, total soluble solids (TSS, total titratable acidity (TTA, pH, ascorbic acid content, total phenolics, and enzyme activities of polyphenoloxidase (PPO and peroxidase (POD. Treatment at 40°C preserved eatable conditions up to 6 days, although calcium affected the appearance of the peel as soon as 4 days. Flesh browning was detected only on the 8th day in untreated fruits, after an increase in PPO and POD activities and total phenolics, and a decrease in ascorbic acid content. The weight loss was continuous throughout the storage period, with no signifi cant difference between treatments. TTA and TSS contents increased and pH decreased during the experiment. Results suggest that CaCl2 dipping had a positive effect on fl esh browning, which was reduced, while heat treatment showed a synergic effect, which could be related broadly with a fall in PPO activity. The variations in ascorbic acid content during storage suggest that the warm dipping combined with CaCl2, contributed to the antioxidant capacity of the fruit.

  17. Experimental investigations of the performance of a solar air collector with latent heat thermal storage integrated with the solar absorber

    Directory of Open Access Journals (Sweden)

    Hejcik J.

    2013-04-01

    Full Text Available The paper deals with experimental investigations of the performance of a solar air collector with latent heat thermal storage integrated with the solarabsorber. The main purpose of heat storage in solar thermal systems is to store heat when the supply of solar heat exceeds demand and release it when otherwise. A number of heat storage materials can be used for this purpose; the phase change materials among them. Short-term latent heat thermal storage integrated with the solar absorber can stabilize the air temperature at the outlet of the collector on cloudy days when solar radiation intensity incident on a solar collector fluctuates significantly. Two experimental front-and-back pass solar air collectors of the same dimensions have been built for the experimental investigations. One collector had a “conventional” solar absorber made of a metal sheet while the solar absorber of the other collector consisted of containers filled with organic phase change material. The experimental collectors were positioned side by side during the investigations to ensure the same operating conditions (incident solar radiation, outdoor temperature.

  18. Dynamic heat transfer problems in a thermal storage unit with packed bed of encapsulated PCM. Analysis in the case of fusible alloy

    Energy Technology Data Exchange (ETDEWEB)

    Asahina, Tadashi; Kosaka, Mineo (Government Industrial Research Inst., Nagoya (Japan))

    1989-06-10

    It is important to know the dynamical properties of a heat storage unit for effective use of energy at low temperature for air conditioning and hot water supply. In the present study, in order to clarify a dynamical heat transfer characteristic of encapsulated heat storage unit in which a fusible alloy was packed as a phase change type heat storage material, temperature changes of the heat storage material and the heat transfer media injecting hot or cold air were measured and were compared with calculated results. Sn-Pb-Bi based molten Rose's alloy metal was poured into the cylindrical aluminum capsules of 20 mm in outside diameter, 1 mm in thickness and 20 mm in height. The packed bed was composed of 4430 capsules stacked in ten steps. Measured values of temperature change of the heat storage unit in the process of heat storage and radiation conformed sufficiently with calculated values, and thus showed that an assumed simple models in calculation were adequate. This heat storage unit with packed bed of encapsulated phase change material has comparatively sufficient characteristic of heat trantsient response and has a wider range of application as a higher efficient heat storage unit with constant temperature thermal output. 13 refs., 9 figs.

  19. Prestorage heat treatment to maintain nutritive and functional properties during postharvest cold storage of pomegranate.

    Science.gov (United States)

    Mirdehghan, Seyed Hossein; Rahemi, Majid; Serrano, María; Guillén, Fabian; Martínez-Romero, Domingo; Valero, Daniel

    2006-11-01

    Heat treatments have been used to extend storability of several fruits, although no information is available about their effects on nutritive and functional properties in pomegranates, which was the objective of this research. Thus, pomegranate fruits were heat treated (dips at 45 degrees C for 4 min) and stored at 2 degrees C for 90 days. Every 15 days, samples were taken and further stored 2 days at 20 degrees C for shelf life study. Arils from heat-treated pomegranates exhibited higher total antioxidant activity than controls, which was correlated primarily to the high levels of total phenolics and to lesser extent to ascorbic acid and anthocyanin contents. Additionally, the levels of sugars (glucose and fructose) and organic acids (malic, citric, and oxalic acids) remained also at higher concentrations in arils from treated fruits. With this simple and non-contaminant technology, the functional and nutritive properties, after long periods of storage, could then be even greater than in recently harvested fruits, thus providing a high content in health-beneficial compounds to consumers after the intake of these fruits.

  20. Heat transfer analysis of the MACSTOR/KN-400 storage module for CANDU spent fuel

    Energy Technology Data Exchange (ETDEWEB)

    Lee, K. H.; Youn, J. H.; Choi, B. I.; Lee, H. Y. [Nuclear Environment Technology Institute, Taejon (Korea, Republic of)

    2003-10-01

    It was verified through heat transfer analysis that a consolidated dry storage system for CANDU spent fuel, MACSTOR/KN-400 was safe in thermal aspect. In order to validate the computer code of CATHENA which was employed to perform the analysis, the comparison between actual measurement data of MACSTOR-200 at Getilly-2 NPP in Canada and computed values from the code has been carried out. The comparison represented that the computed values acceptably agreed to the measurement data and thus the computer code was verified for its application to MACSTOR/KN-400. The identical K-values(parameter to describe head loss inside the module) and convective heat transfer coefficient of the module obtained by the validation was applied to the heat transfer analysis modelling of MACSTOR/KN-400. The result from the analysis showed that under 40 .deg. C of ambient temperature, maximum average and local temperatures of the concrete module were represented by 53 .deg. C and 69 .deg. C, respectively, which fulfilled well the allowable temperature limit of the concrete structure given by ACI349(American Concrete Institute)

  1. Heat Storage Performance of the Prefabricated Hollow Core Concrete Deck Element with Integrated Microencapsulated Phase Change Material

    DEFF Research Database (Denmark)

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

    2012-01-01

    of thermal properties of standard concrete material and pure PCM. Consequently, the numerical models of the decks were updated with the experimentally determined thermal properties of PCM concrete after these two materials have been combined into one material. Finally, the heat storage of the decks......The paper presents the numerically calculated dynamic heat storage capacity of the prefabricated hollow core concrete deck element with and without microencapsulated phase change material (PCM). The reference deck is the ordinary deck made of standard concrete material and that is broadly used...... in many emerging buildings. The new concrete deck with microencapsulated PCM is the standard deck on which one more layer with PCM concrete was added and at the same time the latent heat storage was introduced to the construction. The challenge to simulate the performance of the new deck with PCM concrete...

  2. Development of PFAS-heat storage type air conditioning system with individual heat pump. Chikunetsushiki kobetsu hito ponpu kucho system 'PFAS' no kaihatsu

    Energy Technology Data Exchange (ETDEWEB)

    Okubo, S. (Tokyo Electric Power Co., Inc. (Japan)); Seki, Y. (Takasago Thermal Engineering Co. Ltd., Tokyo (Japan)); Igarashi, M. (Nippon P-MAC Co. Ltd., Tokyo (Japan))

    1993-12-05

    With various uses of building, a good air conditioning system with individual control is needed. Meanwhile, the maximum electric power during summer days is increasing year by year, equalization of electricity load consumed by air conditioning system becomes an important subject in the aspect of stable supply of energy. For meeting these requirements, authors developed a system of the PMAC fancoil air conditioning and heat storage system (PFAS) which provides with a distributed individual type hydrothermal source air conditioner and a heat storage system. This paper introduced a summary of the PFAS system and some operating examples. This system was constructed by the air conditioning unit of combining a hydrothermal source unitary heat pump with a fancoil, a machine of a heat source such as an air cooling heat pump, a heat storage tank and a control system, and it realized equalization of electricity load consumed and saving the running cost of the air conditioning system owing to the night electric use. 8 refs.

  3. Transparent building-integrated PV modules. Phase 1: Comprehensive report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-09-28

    This Comprehensive Report encompasses the activities that have been undertaken by Kiss + Cathcart, Architects, in conjunction with Energy Photovoltaics, Incorporated (EPV), to develop a flexible patterning system for thin-film photovoltaic (PV) modules for building applications. There are two basic methods for increasing transparency/light transmission by means of patterning the PV film: widening existing scribe lines, or scribing a second series of lines perpendicular to the first. These methods can yield essentially any degree of light transmission, but both result in visible patterns of light and dark on the panel surface. A third proposed method is to burn a grid of dots through the films, independent of the normal cell scribing. This method has the potential to produce a light-transmitting panel with no visible pattern. Ornamental patterns at larger scales can be created using combinations of these techniques. Kiss + Cathcart, Architects, in conjunction with EPV are currently developing a complementary process for the large-scale lamination of thin-film PVs, which enables building integrated (BIPV) modules to be produced in sizes up to 48 in. x 96 in. Flexible laser patterning will be used for three main purposes, all intended to broaden the appeal of the product to the building sector: To create semitransparent thin-film modules for skylights, and in some applications, for vision glazing.; to create patterns for ornamental effects. This application is similar to fritted glass, which is used for shading, visual screening, graphics, and other purposes; and to allow BIPV modules to be fabricated in various sizes and shapes with maximum control over electrical characteristics.

  4. Low Cost Thin Film Building-Integrated Photovoltaic Systems

    Energy Technology Data Exchange (ETDEWEB)

    Dr. Subhendu Guha; Dr. Jeff Yang

    2012-05-25

    The goal of the program is to develop 'LOW COST THIN FILM BUILDING-INTEGRATED PV SYSTEMS'. Major focus was on developing low cost solution for the commercial BIPV and rooftop PV market and meet DOE LCOE goal for the commercial market segment of 9-12 cents/kWh for 2010 and 6-8 cents/kWh for 2015. We achieved the 2010 goal and were on track to achieve the 2015 goal. The program consists of five major tasks: (1) modules; (2) inverters and BOS; (3) systems engineering and integration; (4) deployment; and (5) project management and TPP collaborative activities. We successfully crossed all stage gates and surpassed all milestones. We proudly achieved world record stable efficiencies in small area cells (12.56% for 1cm2) and large area encapsulated modules (11.3% for 800 cm2) using a triple-junction amorphous silicon/nanocrystalline silicon/nanocrystalline silicon structure, confirmed by the National Renewable Energy Laboratory. We collaborated with two inverter companies, Solectria and PV Powered, and significantly reduced inverter cost. We collaborated with three universities (Syracuse University, University of Oregon, and Colorado School of Mines) and National Renewable Energy Laboratory, and improved understanding on nanocrystalline material properties and light trapping techniques. We jointly published 50 technical papers in peer-reviewed journals and International Conference Proceedings. We installed two 75kW roof-top systems, one in Florida and another in New Jersey demonstrating innovative designs. The systems performed satisfactorily meeting/exceeding estimated kWh/kW performance. The 50/50 cost shared program was a great success and received excellent comments from DOE Manager and Technical Monitor in the Final Review.

  5. 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

  6. Investigation and optimisation of heat storage tanks for low-flow SDHW systems[Solar Domestic Hot Water

    Energy Technology Data Exchange (ETDEWEB)

    Knudsen, Soeren

    2004-07-01

    This thesis, 'Investigation and optimisation of heat storage tanks for low-flow SDHW systems', describes a study of the heat transfer and flow structure in vertical mantle heat exchangers for low-flow Solar Domestic Hot Water (SDHW) systems. The heat storage is a key component in SDHW systems and the vertical mantle heat exchanger is one of the most promising heat storage designs for low-flow SDHW systems. The study was carried out using a combination of experimental and numerical methods. Thermal experiments of mantle heat exchangers with different mantle inlet designs showed that the mantle inlet port with advantage can be located a distance from the top of the mantle. Consequently, the mantle heat exchangers marketed today can be improved by changing the mantle inlet position. The heat transfer and flow structure in mantle heat exchangers are rather complex and the thermal experiments were followed by investigations by means of advanced experimental and numerical techniques such as Particle Image Velocimetry (PIV) and Computational Fluid Dynamics (CFD). Using a transparent glass mantle tank, experimental flow visualisation was carried out with a PIV system. The flow structures inside the mantle and inside the tank were visualised and then compared with the flow structures predicted by CFD-models. The investigations showed that the CFD-models were able to model the flow in the mantle and in the tank correctly. The CFD-models were also validated by means of thermal experiments with a steel mantle tank. With the verified CFD-models, a parameter analysis was carried out for differently designed mantle heat exchangers for different typical conditions to reveal how the mantle tank parameters influence the flow structure and heat transfer in mantle heat exchangers. The heat transfer in the mantle near the mantle inlet port showed to be in the mixed convection regime, and as the distance from the inlet increased, natural convection started to dominate. The

  7. Effect of Calcium Lactate and Heat-Shock on Texture in Fresh-Cut Lettuce During Storage

    OpenAIRE

    Martin-Diana, Ana Belen; Rico, Daniel; Frias, Jesus Maria; Henehan, Gary; Mulcahy, Jemina; Barat, J.; Barry-Ryan, Catherine

    2006-01-01

    Textural and microstructural changes in fresh-cut lettuce were analysed over 12 days storage. The vegetable was treated with 120 ppm chlorine and with 15 g/L calcium lactate at room temperature (18–20 °C) and at 50 °C (heat-shock). Texturometer analysis showed that samples washed with calcium lactate had significantly (p > 0.05) higher crispness values than samples washed with chlorine. However the use of 50 °C treatment (heat-shock) gave better textural properties at the end of storage and s...

  8. Longitudinal and transverse heating of a relativistic electron bunch induced by a storage ring free electron laser

    Directory of Open Access Journals (Sweden)

    M. Labat

    2006-10-01

    Full Text Available The new trend is to operate storage ring based light sources in a “chromatic mode” with a distributed dispersive function in the straight sections for low emittance. The electron bunch heating induced by a storage ring free electron laser (FEL has been investigated for such optics, and exhibits a more complex saturation process as compared to a usual achromatic mode of operation without dispersion in the straight sections. The correlated measured FEL power is then interpreted in terms of the electron bunch heating and compared to theoretical expectations. Experiments performed at UVSOR-II are here reported. The theoretical interpretation of the new saturation phenomenon is then discussed.

  9. Finite Element Method Modeling of Sensible Heat Thermal Energy Storage with Innovative Concretes and Comparative Analysis with Literature Benchmarks

    Directory of Open Access Journals (Sweden)

    Claudio Ferone

    2014-08-01

    Full Text Available Efficient systems for high performance buildings are required to improve the integration of renewable energy sources and to reduce primary energy consumption from fossil fuels. This paper is focused on sensible heat thermal energy storage (SHTES systems using solid media and numerical simulation of their transient behavior using the finite element method (FEM. Unlike other papers in the literature, the numerical model and simulation approach has simultaneously taken into consideration various aspects: thermal properties at high temperature, the actual geometry of the repeated storage element and the actual storage cycle adopted. High-performance thermal storage materials from the literatures have been tested and used here as reference benchmarks. Other materials tested are lightweight concretes with recycled aggregates and a geopolymer concrete. Their thermal properties have been measured and used as inputs in the numerical model to preliminarily evaluate their application in thermal storage. The analysis carried out can also be used to optimize the storage system, in terms of thermal properties required to the storage material. The results showed a significant influence of the thermal properties on the performances of the storage elements. Simulation results have provided information for further scale-up from a single differential storage element to the entire module as a function of material thermal properties.

  10. Thermal storage and nonlinear heat-transfer characteristics of PCM wallboard

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yinping; Lin, Kunping; Jiang, Yi; Zhou, Guobing [Department of Building Science, Tsinghua University, Beijing 100084 (China)

    2008-07-01

    For the materials with constant thermophysical properties, the thermal performance of wallboards (or floor, ceiling) can be described by decrement factor f and time lag {phi}. However, the phase change material (PCM) may charge large heat during the melting process and discharge large heat during the freezing process, which takes place at some certain temperature or a narrow temperature range. The behavior deviates a lot from the material with constant thermal physical properties. Therefore, it is not reasonable to analyze the thermal performance of PCM wallboard by using the decrement factor f and time lag {phi}. How to simply and effectively analyze the thermal performance of a PCM wallboard is an important problem. In order to analyze and evaluate the energy-efficient effects of the PCM wallboard and floor, two new parameters, i.e., modifying factor of the inner surface heat flux '{alpha}' and ratio of the thermal storage 'b', are put forward. They can describe the thermal performance of PCM external and internal walls, respectively. The analysis and simulation methods are both applied to investigate the effects of different PCM thermophysical properties (heat of fusion H{sub m}, melting temperature T{sub m} and thermal conductivity k) on the thermal performance of PCM wallboard for the residential buildings. The results show that the PCM external wall can save more energy by increasing H{sub m}, decreasing k and selecting proper T{sub m} ({alpha}<1); that the PCM internal wall can save more energy by increasing H{sub m} and selecting appropriate T{sub m}, k. The most energy-efficient approach of applying PCM in a solar house is to apply it in its internal wall. (author)

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

    Energy Technology Data Exchange (ETDEWEB)

    Trelles, J.P.; Dufly, J.J. [University of Massachusettes Lowell, MA (United States). Dept. of Energy Engineering

    2003-09-01

    Porous latent heat thermal energy storage for thermoelectric cooling is simulated via a matrix-based enthalpy formulation, having the temperature as unknown, in a three-dimensional domain. The system is made up of two aluminum containers; the inner one contains the cooling objective in water suspension and the outer one the phase change material (PCM) in a porous aluminum matrix. The system's charging and discharging processes are simulated for constant thermoelectric module cold side temperature under different porosities of the aluminum matrix. The mathematical modeling approach simplifies the analysis while the metal matrix in the PCM greatly improves performance. A direct application of the studied system is vaccine conservation in solar powered thermoelectric cooling systems. (Author)

  12. Dynamic thermal behavior of building using phase change materials for latent heat storage

    Directory of Open Access Journals (Sweden)

    Selka Ghouti

    2015-01-01

    Full Text Available This study presents a two-dimensional model with a real size home composed of two-storey (ground and first floor spaces separated by a slab, enveloped by a wall with rectangular section containing phase change material (PCM in order to minimize energy consumption in the buildings. The main objective of the PCM-wall system is to decrease the temperature change from outdoor space before it reaches the indoor space during the daytime. The numerical approach uses effective heat capacity Ceff model with realistic outdoor climatic conditions of Tlemcen city, Algeria. The numerical results showed that by using PCM in wall as energy storage components may reduce the room temperature by about 6 to 7°C of temperature depending on the floor level (first floor spaces or ground floor spaces.

  13. Numerical analysis of melting of nano-enhanced phase change material in latent heat thermal energy storage system

    Directory of Open Access Journals (Sweden)

    Kashani Sina

    2014-01-01

    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 exhibit enhanced thermal conductivity in comparison to the base material. Calculation is performed for nanoparticle volume fraction from 0 to 0.08. In this study rectangular and cylindrical containers are modeled numerically and the effect of containers dimensions and nano particle volume fraction are studied. It has been found that the rectangular container requires half of the melting time as for the cylindrical container of the same volume and the same heat transfer area and also, higher nano particle volume fraction result in a larger solid fraction. The increase of the heat release rate of the nanoparticle-enhanced phase change materials shows its great potential for diverse thermal energy storage application.

  14. Central receiver solar thermal power system, Phase 1. CDRL Item 2. Pilot plant preliminary design report. Volume V. Thermal storage subsystem. [Sensible heat storage using Caloria HT43 and mixture of gravel and sand

    Energy Technology Data Exchange (ETDEWEB)

    Hallet, Jr., R. W.; Gervais, R. L.

    1977-10-01

    The proposed 100-MWe Commercial Plant Thermal Storage System (TSS) employs sensible heat storage using dual liquid and solid media for the heat storage in each of four tanks, with the thermocline principle applied to provide high-temperature, extractable energy independent of the total energy stored. The 10-MW Pilot Plant employs a similar system except uses only a single tank. The high-temperature organic fluid Caloria HT43 and a rock mixture of river gravel and No. 6 silica sand were selected for heat storage in both systems. The system design, installation, performance testing, safety characteristics, and specifications are described in detail. (WHK)

  15. Numerical Study of Thermal Performance of Phase Change Material Energy Storage Floor in Solar Water Heating System

    Institute of Scientific and Technical Information of China (English)

    ZENG Ruo-lang; WANG Xin; ZHANG Yin-ping; DI Hong-fa; ZHANG Qun-li

    2009-01-01

    The conventional solar heating floor system contains a big water tank to store energy in the day time for heating at night,which takes much building space and is very heavy.In order to reduce the water tank velume even to cancel the tank,a novel structure of integrated water pipe floor heating system using shape-stabi-lized phase change materials (SSPCM) for thermal energy storage was developed.A numerical model was devel-oped to analyze the performance of SSPCM floor heating system under the intermittent heating condition,which was verified by our experimental data.The thermal performance of the heating system and the effects of various factors on it were analyzed numerically.The factors including phase transition temperature,heat of fusion,ther-real conductivity of SSPCM and thermal conductivity of the decoration material were analyzed.The results show that tm and kd are the most import influencing factors on the thermal performance of SSPCM floor heating sys-tem,since they determine the heat source temperature and thermal resistance between SSPCM plates and indoor air,respectively.Hm should be large to store enough thermal energy in the day time for nighttimes heating.The effects of KP can be ignored in this system.The SSPCM floor heating system has potential of making use of the daytime solar energy for heating at night efficiently in various climates when its structure is properly designed.

  16. Body heat storage during physical activity is lower with hot fluid ingestion under conditions that permit full evaporation.

    Science.gov (United States)

    Bain, A R; Lesperance, N C; Jay, O

    2012-10-01

    To assess whether, under conditions permitting full evaporation, body heat storage during physical activity measured by partitional calorimetry would be lower with warm relative to cold fluid ingestion because of a disproportionate increase in evaporative heat loss potential relative to internal heat transfer with the ingested fluid. Nine males cycled at 50% VO(2max) for 75 min at 23.6 ± 0.6 °C and 23 ± 11% RH while consuming water of either 1.5 °C, 10 °C, 37 °C or 50 °C in four 3.2 mL kg(-1) boluses. The water was administered 5 min before and 15, 30 and 45 min following the onset of exercise. No differences in metabolic heat production, sensible or respiratory heat losses (all P > 0.05) were observed between fluid temperatures. However, while the increased internal heat loss with cold fluid ingestion was paralleled by similar reductions in evaporative heat loss potential at the skin (E(sk) ) with 10 °C (P = 0.08) and 1.5 °C (P = 0.55) fluid, the increased heat load with warm (50 °C) fluid ingestion was accompanied by a significantly greater E(sk) (P = 0.04). The resultant calorimetric heat storage was lower with 50 °C water ingestion in comparison to 1.5 °C, 10 °C and 37 °C (all P heat storage derived conventionally using thermometry yielded higher values following 50 °C fluid ingestion compared to 1.5 °C (P = 0.025). Under conditions permitting full sweat evaporation, body heat storage is lower with warm water ingestion, likely because of disproportionate modulations in sweat output arising from warm-sensitive thermosensors in the esophagus/stomach. Local temperature changes of the rectum following fluid ingestion exacerbate the previously identified error of thermometric heat storage estimations. © 2012 The Authors Acta Physiologica © 2012 Scandinavian Physiological Society.

  17. Thermal Energy Storage for Building Load Management: Application to Electrically Heated Floor

    Directory of Open Access Journals (Sweden)

    Hélène Thieblemont

    2016-07-01

    Full Text Available In cold climates, electrical power demand for space conditioning becomes a critical issue for utility companies during certain periods of the day. Shifting a portion or all of it to off-peak periods can help reduce peak demand and reduce stress on the electrical grid. Sensible thermal energy storage (TES systems, and particularly electrically heated floors (EHF, can store thermal energy in buildings during the off-peak periods and release it during the peak periods while maintaining occupants’ thermal comfort. However, choosing the type of storage system and/or its configuration may be difficult. In this paper, the performance of an EHF for load management is studied. First, a methodology is developed to integrate EHF in TRNSYS program in order to investigate the impact of floor assembly on the EHF performance. Then, the thermal comfort (TC of the night-running EHF is studied. Finally, indicators are defined, allowing the comparison of different EHF. Results show that an EHF is able to shift 84% of building loads to the night while maintaining acceptable TC in cold climate. Moreover, this system is able to provide savings for the customer and supplier if there is a significant difference between off-peak and peak period electricity prices.

  18. 2D Conduction Simulation of a PCM Storage Coupled with a Heat Pump in a Ventilation System

    Directory of Open Access Journals (Sweden)

    Joseph Virgone

    2016-06-01

    Full Text Available Efforts to simulate heat transfer in a PCM (Phase Change Material storage device are generally led by considerations of Biot number and material thickness, of 2D versus 1D representation, and of possible hysteresis effects arising from the characterisation of the PCM using differential scanning calorimetry (DSC. In this paper we present a numerical treatment of heat conduction in a paraffin-based storage brick, based on experimental data for a full scale, heat storage component studied under laboratory conditions. The PCM was modelled adopting equivalent thermophysical properties during the phase change. An equivalent heat capacity and thermal conductivity were provided for an appropriate description of energy release and storage in the process of solidification and melting. The geometry of the metal container induces 2D effects that are generally neglected in numerical modelling. The thickness of the plates (about 2 cm is sufficiently large to require the modelling of conduction in the PCM, but can also induce convection that has been neglected in this study. Experimental results are presented and compared for both a 1D and 2D model of the PCM device. It was concluded that a 2D representation is essential for configurations; like the case study and geometry we had; with a large difference in thermal conductivity between PCM and metal casing. Two curves of equivalent heat capacity (measured via DSC were introduced for heating and cooling phases. Comparisons to experimental results indicated significant errors in the models during melting and solidification of the PCM, which could be reduced by instead adopting the mean of the two heat capacity curves. The rate of temperature change during the experiments and for the DSC characterisation was analysed and found to explain well the observations. In particular, as novelty, two peaks of equivalent heat capacity have been observed with DSC when the rate is very low instead of only one peak using

  19. Numerical performance study of paraffin wax dispersed with alumina in a concentric pipe latent heat storage system

    OpenAIRE

    Valan Arasu Amirtham; Sasmito Agus P.; Mujumdar Arun S.

    2013-01-01

    Latent heat energy storage systems using paraffin wax could have lower heat transfer rates during melting/freezing processes due to its inherent low thermal conductivity. The thermal conductivity of paraffin wax can be enhanced by employing high conductivity materials such as alumina (Al2O3). A numerical analysis has been carried out to study the performance enhancement of paraffin wax with nanoalumina (Al2O3) particles in comparison with simple paraffin wax in a concentric double pipe ...

  20. The capric and lauric acid mixture with chemical additives as latent heat storage materials for cooling application

    Energy Technology Data Exchange (ETDEWEB)

    Roxas-Dimaano, M.N. [University of Santo Tomas, Manila (Philippines). Research Center for the Natural Sciences; Watanabe, T. [Tokyo Institute of Technology (Japan). Research Laboratory for Nuclear Reactors

    2002-09-01

    The mixture of capric acid and lauric acid (C-L acid), with the respective mole composition of 65% and 35%, is a potential phase change material (PCM). Its melting point of 18.0{sup o}C, however, is considered high for cooling application of thermal energy storage. The thermophysical and heat transfer characteristics of the C-L acid with some organic additives are investigated. Compatibility of C-L acid combinations with additives in different proportions and their melting characteristics are analyzed using the differential scanning calorimeter (DSC). Among the chemical additives, methyl salicylate, eugenol, and cineole presented the relevant melting characteristics. The individual heat transfer behavior and thermal storage performance of 0.1 mole fraction of these additives in the C-L acid mixture are evaluated. The radial and axial temperature distribution during charging and discharging at different concentrations of selected PCM combinations are experimentally determined employing a vertical cylindrical shell and tube heat exchanger. The methyl salicylate in the C-L acid provided the most effective additive in the C-L acid. It demonstrated the least melting band width aimed at lowering the melting point of the C-L acid with the highest heat of fusion value with relatively comparable rate of heat transfer. Furthermore, the thermal performance based on the total amount of transferred energy and their rates, established the PCM's latent heat storage capability. (author)

  1. An Experimental Study on Thermal Characteristics of Lauric Acid as a Latent Heat Storage Material during Melting Process

    Institute of Scientific and Technical Information of China (English)

    AhmetSARI

    2003-01-01

    The objective of this study was to establish the thermal characteristics of the lauric acid (95% purity) as a latent heat storage material filled in the annulus of vertical concentric double pipe during its melting process,The temperature data were used to determine the thermal characteristics,including the temporal temperature variations and the effects of the mass flow rate and the inlet temperature of the heat transfer fluid on the heat transfer coefficient and the heat charging fraction during the melting process,The results indicated that the time to reach to heat charging fraction of 1.0 could be altered by changing the mass flow rate and the inlet temperature of the heat transfer fluid.

  2. Proceedings of solar energy storage options. Volume I. An intensive workshop on thermal energy storage for solar heating and cooling

    Energy Technology Data Exchange (ETDEWEB)

    None

    1979-01-01

    Separate abstracts were prepared for the 28 papers presented. Panel chairmen's summaries are included; the complete panel reports will be published in Volume II of the Solar Energy Storage Options Workshop proceedings. (WHK)

  3. Development of salt hydrate eutectics as latent heat storage for air conditioning and cooling

    Energy Technology Data Exchange (ETDEWEB)

    Efimova, Anastasia [Brandenburgische Technische Universität (BTU) Cottbus – Senftenberg, Chair of Inorganic Chemistry, Großenhainer Str. 57, 01968 Senftenberg (Germany); Pinnau, Sebastian; Mischke, Matthias; Breitkopf, Cornelia [Technische Universität Dresden, Chair of Technical Thermodynamics, Helmholtzstr. 14, 01069 Dresden (Germany); Ruck, Michael [Technische Universität Dresden, Chair of Inorganic Chemistry, Bergstr. 66, 01062 Dresden (Germany); Schmidt, Peer, E-mail: peer.schmidt@hs-lausitz.de [Brandenburgische Technische Universität (BTU) Cottbus – Senftenberg, Chair of Inorganic Chemistry, Großenhainer Str. 57, 01968 Senftenberg (Germany)

    2014-01-10

    Graphical abstract: - Highlights: • Inorganic salt hydrates. • Latent heat thermal energy storage. • Thermal behavior of melting and crystallization. • Cycling stability. • Nucleation. - Abstract: Sustainable air conditioning systems require heat reservoirs that operate between 4 and 20 °C. A systematic search for binary and ternary eutectics of inorganic salts and salt hydrates with melting temperatures in this temperature regime and with high enthalpies of fusion has been performed by means of differential scanning calorimetry (DSC). Promising results were obtained for the pseudo-ternary system Zn(NO{sub 3}){sub 2}·6H{sub 2}O, Mn(NO{sub 3}){sub 2}·4H{sub 2}O, and KNO{sub 3} with the melting temperature range 18–21 °C and the enthalpy of fusion of about 110 kJ kg{sup −1}. Suitable nucleating and thickening agents have been found and tested to prevent the mixture from supercooling and phase separation.

  4. Development of a Hydrogen and Heat Storage System for Satellite Applications

    Science.gov (United States)

    Reissner, Alexander; Pawelke, Roland; Hummel, Stefan; Gerger, Joachim; Lutz, Matthias; Farnes, Jarle; Vik, Arild; Wernhus, Ivar; Svendsen, Tjalve; Schautz, Max; Geneste, Xavier

    2014-08-01

    Next generation telecommunication satellites will demand increasingly more power in the range of 30 kW or more within the next 10 years. Battery technology that can sustain 30 kW for an eclipse length of up to 72 minutes will represent a major impact on the total mass of the satellite, even with new Li-ion battery technologies. Regenerative fuel cell systems (RFCS) were identified years ago as a possible alternative to rechargeable batteries. They consist of a dedicated fuel cell unit for electricity generation and a dedicated electrolyser which regenerates the fuel cell reactants hydrogen and oxygen from the fuel cell reaction product water. All units are integrated in a closed loop system. Nevertheless, one major drawback has been identified by several independent system studies [4,5], namely the need to dissipate large amounts of heat from the fuel cell during Eclipse. This in turn requires massive thermal hardware (mainly large radiators) that can contribute up to 50% of the system mass. FOTEC has suggested the use of metal hydrides as combined hydrogen and heat storage system to overcome this issue and is currently manufacturing a technology demonstrator within an ongoing ESA project. The status of these developments is outlined in this paper.

  5. MUNI Ways and Structures Building Integrated Solar Membrane Project

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Randall

    2014-07-03

    The initial goal of the MUNI Ways and Structures Building Integrated Solar Membrane Installation Project was for the City and County of San Francisco (CCSF) to gain experience using the integrated higher efficiency solar photovoltaic (PV) single-ply membrane product, as it differs from the conventional, low efficiency, thin-film PV products, to determine the feasibility of success of larger deployment. As several of CCSF’s municipal rooftops are constrained with respect to weight restrictions, staff of the Energy Generation Group of the San Francisco Public Utilities Commission (SFPUC) proposed to install a solar PV system using single-ply membrane The installation of the 100 kW (DC-STC) lightweight photo voltaic (PV) system at the MUNI Ways and Structures Center (700 Pennsylvania Ave., San Francisco) is a continuation of the commitment of the City and County of San Francisco (CCSF) to increase the pace of municipal solar development, and serve its municipal facilities with clean renewable energy. The fourteen (14) solar photovoltaic systems that have already been installed at CCSF municipal facilities are assisting in the reduction of fossil-fuel use, and reduction of greenhouse gases from fossil combustion. The MUNI Ways & Structures Center roof has a relatively low weight-bearing capacity (3.25 pounds per square foot) and use of traditional crystalline panels was therefore rejected. Consequently it was decided to use the best available highest efficiency Building-Integrated PV (BIPV) technology, with consideration for reliability and experience of the manufacturer which can meet the low weight-bearing capacity criteria. The original goal of the project was to provide an opportunity to monitor the results of the BIPV technology and compare these results to other City and County of San Francisco installed PV systems. The MUNI Ways and Structures Center was acquired from the Cookson Doors Company, which had run the Center for many decades. The building was

  6. Safety issues related to the intermediate heat storage for the EU DEMO

    Energy Technology Data Exchange (ETDEWEB)

    Carpignano, Andrea [NEMO group, Dipartimento Energia, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino (Italy); Pinna, Tonio [ENEA, 00044 Frascati (Italy); Savoldi, Laura; Sobrero, Giulia; Uggenti, Anna Chiara [NEMO group, Dipartimento Energia, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino (Italy); Zanino, Roberto, E-mail: roberto.zanino@polito.it [NEMO group, Dipartimento Energia, Politecnico di Torino, C.so Duca degli Abruzzi 24, 10129 Torino (Italy)

    2016-11-01

    Highlights: • IHS affects only the PHTS and the BoP (Balance of Plant). • PIEs list does not change but IHS influences PIEs evolution. • Additional issues to be addressed in PIEs study due to the implementation of HIS. • No safety/operational major obstacles were found for IHS concept. - Abstract: The functional deviations able to compromise system safety in the EU DEMO Primary Heat Transfer System (PHTS) with intermediate heat storage (IHS) based on molten salts are identified and compared to the deviations identified with PHTS without IHS. The resulting safety issues for the Balance of Plant (BoP) have been taken into account. Functional Failure Mode and Effects Analysis (FFMEA) is used to highlight the Postulated Initiating Events (PIE) of incident/accident sequences and to provide some safety insights during the preliminary design. The architecture of the system with IHS does not introduce new PIE with respect to the case without IHS, but it modifies some of them. In particular the two Postulated Initiating Events that are affected by the presence of IHS are the LOCA in the tubes of the HX between primary and intermediate circuit and the loss of heat sink for the first wall or the breeding zone. In fact the IHS introduces some advantages concerning the stability of the secondary circuit, but some weaknesses are associated to the physical-chemical nature of molten salts, especially oxidizing power, corrosive nature and risk of solidification. These issues can be managed in the design by the introduction of new safety functions.

  7. Interannual variability of mixed layer depth and heat storage of upper layer in the tropical Pacific Ocean

    Institute of Scientific and Technical Information of China (English)

    LIN Yihua; YOU Xiaobao; GUAN Yuping

    2004-01-01

    By using the upper layer data (downloaded trom the web of the Scripps Institution of Oceanography ),the interannual variability of the heat storage of upper layer(from surface to 400 m depth) and the mixed layer depth in the tropical Pacific Ocean are investigated. The abnormal signal of the warm event comes from the central and west Pacific Ocean, whereas it is regarded that the abnormal signal of the warm event comes from the east Pacific Ocean in the popular viewpoint. From the viewpoint on the evolution of the interannual variability of the mixed layer depth and the heat storage of the whole upper layer, the difference between the two types of El Nino is so smallthat it can be neglected. During these two El Nino/La Nina events(1972/1973 and 1997/1998), other than the case of the heat storage or for the mixed layer depth, the abnormal signal propagates from the central and west Pacific Ocean to the east usually by the path along the equator whereas the abnormal signal propagates from the east to the west by the path northern to the equator. For the interannual variability, the evolution of the mixed layer depth corresponds to that of the heat storage in the upper layer very well. This is quite different from the evolution of seasonality.

  8. Energy Simulation of a Holographic PVT Concentrating System for Building Integration Applications

    Directory of Open Access Journals (Sweden)

    Julia Marín-Sáez

    2016-07-01

    Full Text Available A building integrated holographic concentrating photovoltaic-thermal system has been optically and energetically simulated. The system has been designed to be superimposed into a solar shading louvre; in this way the concentrating unit takes profit of the solar altitude tracking, which the shading blinds already have, to increase system performance. A dynamic energy simulation has been conducted in two different locations—Sde Boker (Israel and Avignon (France—both with adequate annual irradiances for solar applications, but with different weather and energy demand characteristics. The simulation engine utilized has been TRNSYS, coupled with MATLAB (where the ray-tracing algorithm to simulate the holographic optical performance has been implemented. The concentrator achieves annual mean optical efficiencies of 30.3% for Sde Boker and 43.0% for the case of Avignon. Regarding the energy production, in both locations the thermal energy produced meets almost 100% of the domestic hot water demand as this has been considered a priority in the system control. On the other hand, the space heating demands are covered by a percentage ranging from 15% (Avignon to 20% (Sde Boker. Finally, the electricity produced in both places covers 7.4% of the electrical demand profile for Sde Boker and 9.1% for Avignon.

  9. Programming MOFs for water sorption: amino-functionalized MIL-125 and UiO-66 for heat transformation and heat storage applications.

    Science.gov (United States)

    Jeremias, Felix; Lozan, Vasile; Henninger, Stefan K; Janiak, Christoph

    2013-12-07

    Sorption-based heat transformation and storage appliances are very promising for utilizing solar heat and waste heat in cooling or heating applications. The economic and ecological efficiency of sorption-based heat transformation depends on the availability of suitable hydrophilic and hydrothermally stable sorption materials. We investigated the feasibility of using the metal-organic frameworks UiO-66(Zr), UiO-67(Zr), H2N-UiO-66(Zr) and H2N-MIL-125(Ti) as sorption materials in heat transformations by means of volumetric water adsorption measurements, determination of the heat of adsorption and a 40-cycle ad/desorption stress test. The amino-modified compounds H2N-UiO-66 and H2N-MIL-125 feature high heat of adsorption (89.5 and 56.0 kJ mol(-1), respectively) and a very promising H2O adsorption isotherm due to their enhanced hydrophilicity. For H2N-MIL-125 the very steep rise of the H2O adsorption isotherm in the 0.1 heat pump application.

  10. Applications of thermal energy storage to process heat and waste heat recovery in the primary aluminum industry. Final report, September 1977-September 1978

    Energy Technology Data Exchange (ETDEWEB)

    Katter, L.B.; Hoskins, R.L.

    1979-04-01

    The results of a study entitled, Applications of Thermal Energy Storage to Process Heat and Waste Heat Recovery in the Primary Aluminum Industry are presented. In this preliminary study, a system has been identified by which the large amounts of low-grade waste energy in the primary pollution control system gas stream can be utilized for comfort heating in nearby communities. Energy is stored in the form of hot water, contained in conventional, insulated steel tanks, enabling a more efficient utilization of the constant energy source by the cyclical energy demand. Less expensive energy storage means (heated ponds, aquifers), when they become fully characterized, will allow even more cost-competitive systems. Extensive design tradeoff studies have been performed. These tradeoff studies indicate that a heating demand equivalent to 12,000 single-family residences can be supplied by the energy from the Intalco plant. Using a 30-year payback criterion (consistent with utility planning practice), the average cost of energy supplied over the system useful life is predicted at one-third the average cost of fossil fuel. The study clearly shows that the utilization of waste energy from aluminum plants is both technically and economically attractive. The program included a detailed survey of all aluminum plants within the United States, allowing the site specific analyses to be extrapolated to a national basis. Should waste heat recovery systems be implemented by 1985, a national yearly savings of 6.5 million barrels of oil can be realized.

  11. Heat recovery from a thermal energy storage based on the Ca(OH){sub 2}/CaO cycle

    Energy Technology Data Exchange (ETDEWEB)

    Azpiazu, M.N. [E.T.S. Ingenieros, Bilbao (Spain). Dpto. de Ingenieria Quimica y del Medio Ambiente; Morquillas, J.M. [E.T.S. Ingenieros, Bilbao (Spain). Dpto. de Maquinas y Motores Termicos; Vazquez, A. [E.S. da Marina Civil, La Coruna (Spain). Dpto. de Energia y Propulsion Maritima

    2003-04-01

    Thermal energy storage is very important in many applications related to the use of waste heat from industrial processes, renewable energies or from other sources. Thermochemical storage is very interesting for long-term storage as it can be carried out at room temperature with no energy losses. Dehydration/hydration cycle of Ca(OH){sub 2}/CaO has been applied for thermal energy storage in two types of reactors. One of them was a prototype designed by the authors, and in the other type conventional laboratory glassware was used. Parameters such as specific heats, reaction rate and enthalpy, mass losses and heat release were monitored during cycles. Although in the hydration step water is normally added in vapour phase, liquid water, at 0{sup o}C has been used in these experiences. Results indicated that the energy storage system performance showed no significant differences, when we compared several hydration/dehydration cycles. The selected chemical reaction did not exhibit a complete reversibility because complete Ca(OH){sub 2} dehydration, was not achieved. However the system could be used satisfactorily along 20 cycles at least. Heat recovery experiments showed general system behaviour during the hydration step in both types of reactors. The designed prototype was more efficient in this step. Main conclusions suggested carrying out one complete cycle at a higher dehydration temperature to recover total system reversibility. A modification of the prototype design trying to enhance heat transfer from the Ca(OH){sub 2} bed could also be proposed. (author)

  12. Performance analysis of a soil-based thermal energy storage system using solar-driven air-source heat pump for Danish buildings sector

    DEFF Research Database (Denmark)

    Jradi, M.; Veje, C.; Jørgensen, B. N.

    2017-01-01

    source. Employing a PV system of 30 kW capacity, it was found that a storage medium of 900 m3 of soil is capable of providing the heating needs for a housing project of 1000 m2 internal floor area. The year round transient behaviour of the thermal energy storage medium is reported in addition to the heat...... and evaluation of the performance of an underground soil-based thermal energy storage system for solar energy storage, coupled with a combined heat and power generation system. A combined PV-Air Source Heat Pump (ASHP) system is utilized to fulfil heating and electricity needs of a housing project in Odense.......2% for the combined PV-ASHP system employing a seasonal underground thermal energy storage block....

  13. Solar assisted absorption or motor driven heat pump with earth seasonal storage: Part 1, Final report, 1 July 1982-30 June 1985

    Energy Technology Data Exchange (ETDEWEB)

    Lazzarin, R.M.

    1986-01-01

    A plant composed of an energy roof, a seasonal earth storage and an absorption heat pump has been tested. The purpose was to study the behavior of the various components and their interaction. The surveys went on during two years. The following operations are considered: the charging of the earth storage by the energy roof and the working of an absorption heat pump connected either to the energy roof or to the earth storage.

  14. Heat release performance of heat storage water tank with phase-change material in solar drying system%太阳能干燥相变储热水箱的放热性能

    Institute of Scientific and Technical Information of China (English)

    于海涛; 高建民; 陈瑶

    2015-01-01

    为降低传统干燥能耗,强化太阳能干燥用储热水箱的储放热能力,在普通储热水箱中添加了硬脂酸/膨胀石墨相变储热材料,研究了放热温差、储热单元体积对装置放热性能的影响。研究结果表明:相变储热水箱放热时间、放热量随着放热温差和储热水箱中储热单元体积的增加均有所提升,储热单元的添加对储热水箱的放热效果影响更为显著。放热效率则随着放热温差的增大而降低,随着储热水箱中储热单元体积的增加而显著提升;储热水箱中储热单元体积为35%时,相变储热水箱的放热时间比普通储热水箱最多提升了1.26倍,放热温度最大可提高8.7℃,热效率最多可提高22.56%。%Drying is an essential process for a large number of industrial and agricultural products. In order to reduce energy consumption of traditional drying, improve its utilization efficiency and strengthen the capacity of heat storage water tank for solar drying, the stearic acid/expanded graphite composite phase-change material (PCM) with melting point of 52.74℃ and latent heat of 169.90 J/g was added into the conventional heat storage water tank in this paper. The schematic structure of the solar drying system mainly consisted of solar collector, drying oven, heat storage water tank and phase-change thermal energy storage units. The effect of heat release temperature difference and heat storage unit volume on the heat release performance of the device was studied under the same heat release conditions. The total volume of the PCM containers in the heat storage water tank was 15%, 25% and 35%, respectively. The heat storage water tank was heated to 60, 65 and 75℃ by using solar collector in heat storage process. Then the heat storage water tank was used to provide heat for the drying oven, and the heat release process was finished when the temperature of drying oven was 40℃ . The results showed that the

  15. Thermal Energy Optimization of Building Integrated Semi-Transparent Photovoltaic Thermal Systems

    OpenAIRE

    Ekoe A Akata Aloys Martial; Donatien Njomo; Basant Agrawal

    2015-01-01

    Building integrated photovoltaic (BIPV) : The concept where the photovoltaic element assumes the function of power generation and the role of the covering component element has the potential to become one of the principal sources of renewable energy for domestic purpose. In this paper, a Building integrated semitransparent photovoltaic thermal system (BISPVT) system having fins at the back sheet of the photovoltaic module has been simulated. It has been observed that this system produces high...

  16. Optical characterisation of semi-transparent PV modules for building integration

    OpenAIRE

    Moralejo Vázquez, Francisco José; Martín Chivelet, Nuria; Olivieri, Lorenzo; Caamaño Martín, Estefanía

    2014-01-01

    A complete characterisation of PV modules for building integration is needed in order to know their influence on the building’s global energy balance. Specifically, certain characteristic parameters should be obtained for each different PV module suitable for building integrated photovoltaics (BIPV), some by direct or indirect measurements at the laboratory, and others by monitoring the element performance mounted in real operating conditions. In the...

  17. Experimental study of an externally finned tube with internal heat transfer enhancement for phase change thermal energy storage

    Science.gov (United States)

    Martinelli, M.; Bentivoglio, F.; Couturier, R.; Fourmigué, J.-F.; Marty, P.

    2016-09-01

    After having presented the design of a latent heat thermal energy storage system (LHTESS) for district heating, experimental results of a vertical tube-in-shell LHTESS are discussed. The tube is radially finned on its external wall to enhance the heat transfer in the phase change material. The test rig is operated with flow conditions corresponding to the proposed design. As the internal flow of heat transfer fluid (HTF) appears to be laminar and is highly influenced by buoyancy forces, which results in mixed convection regime, cross-sectional area reducers are installed inside the HTF tube in order to reduce the Rayleigh number and thus natural convection. Experimental results are presented for two finned tubes, with and without internal heat transfer enhancement respectively.

  18. Thermal performance of a heat storage module using PCM's with different melting temperature; Experimental

    Energy Technology Data Exchange (ETDEWEB)

    Farid, M.M. (Chemical Engineering Dept., College of Engineering, Univ. of Basrah (IQ)); Kim, Y.; Kansawa, A. (Chemical Engineering Dept., Tokyo Inst. of Technology, O-Okayama, Meguro-Ku, Tokyo 152 (JP))

    1990-05-01

    A latent heat storage module was constructed, consisting of 45 cylindrical capsules fixed vertically in 15 rows. The capsules, made of 0.335-m long copper tubes having external diameters of 31.8 mm, were fixed in an insulated rectangular duct. Three commercial waxes having melting temperatures of 44{degrees}C, 53{degrees}C, and 64{degrees}C were selected. Each of the three sets of 15 tubes was filled with different wax. For comparison purposes, experiments were also done with a single commercial wax, having a melting temperature of 53{degrees}C, in all the tubes. During heat charge, hot air flowed across the capsules such that the melting temperature of the waxes decreased in the flow direction. Air flow direction was reversed during heat discharge. This paper reports that experimental measurements showed some improvement in the heat transfer rates during both heat charge and discharge when three types of PCM's were used.

  19. Large-volume heat storage tank made of GFK; Grosswaermespeichertank aus GFK

    Energy Technology Data Exchange (ETDEWEB)

    Buehl, J.; Schultheis, P. [Technische Univ. Ilmenau (Germany). Fachgebiet Technische Thermodynamik

    1998-12-31

    The Technical University of Ilmenau, the company Verbundwerkstoff- und Kunststoffanwendungstechnik Schoenbrunn, the Institute for Aerospace and Light-weight construction of Dresden University with its approved testing facilities for plastics and the Institute for Construction Engineering in Berlin and several other institutions co-operated since 1996 in developing a concept for a series of long-term heat storage tanks up to 6,000 cubic metres storage volume made of plastic (GFK components) with a combined thermal insulation. A model tank (sandwich body with proportional thermal insulation layer and selected mixed laminates) with a volume of 1.5 cubic metres was built and installed in November 1996. The tank has been continuously operated at various test levels. The experiment proves the longevity of the materials used. (orig.) [Deutsch] In Zusammenarbeit der TU Ilmenau mit der Fa. Verbundwerkstoff - und Kunststoffanwendungstechnik Schoenbrunn und dem Institut fuer Luftfahrttechnik und Leichtbau Dresden, seiner akkredierten Pruefstelle fuer Kunststoffe, in Abstimmung mit dem Institut fuer Bautechnik Berlin und weiteren Einrichtungen und Partnern wird seit 1996 an einem Konzept fuer eine Typenreihe Langzeitwaermespeicher bis vorerst 6.000 m{sup 3} Speichervolumen aus Kunststoff (GFK-Komponenten) und kombinierter integrierter thermischer Isolation gearbeitet. Im Vorfeld dieser Entwicklung wurde auf der Basis vorausgewaehlter Materialien und Kompositionen ein Musterspeicher (ein Sandwich - Modellkoerper mit proportionaler Waermedaemmschicht sowie ausgewaehlten Mischlaminaten) mit einem Speichervolumen von 1,5 m{sup 3} realisiert. Dieser Musterspeicher wurde im November 1996 installiert und wird seither kontinuierlich in den entsprechenden Erprobungsstufen betrieben. Der Nachweis der Langlebigkeit der eingesetzten Materialien wurde experimentell erbracht. (orig.)

  20. The influence of dry matter, applied heat treatment and storage period on the viscosity of stirred yogurt

    Directory of Open Access Journals (Sweden)

    Denin-Đurđević Jelena D.

    2002-01-01

    Full Text Available Skim milk powder reconstituted to 8.44% TS, 9.65% TS and 10.84% TS respectively was used for investigation. Untreated milk and milk heat treated at 85ºC/20 min and 90ºC/10 min, respectively, were used for the investigation. Milk was inoculated with 2.5% of yogurt culture (containing Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus in the ratio 1:1 at 43ºC. Samples were incubated until pH 4.6 was reached. Samples were immediately cooled to 4ºC and held at that temperature during 14 days. Acid casein gel was stirred after 1, 7 and 14 days of storage. Measurements were done at 30 rpm during 2 min, at 20ºC. According to the investigation, it could be concluded that both applied heat treatment and dry matter content influence viscosity of stirred yogurt. Viscosity increases when dry matter content increases. The smallest viscosity had yogurt produced from untreated milk with 8.44% TS, while samples produced from milk with 10.84% TS had the highest viscosity. Applied heat treatments had significant influence on viscosity of yogurt gained by stirring of acid casein gels after 7 and 14 days of storage. Stirred yogurt produced from milk heat treated at 90ºC/10 min had a higher viscosity than samples produced from milk heat treated at 85ºC/20 min. Storage period influenced average viscosity of stirred yogurt. Samples of stirred yogurt produced from milk with 8.44% TS showed a decrease of average viscosity during storage regardless of the applied heat treatment of milk. The highest average viscosity had samples produced from milk with 10.84% TS.

  1. Solar Thermoelectricity via Advanced Latent Heat Storage: A Cost-Effective Small-Scale CSP Application

    Energy Technology Data Exchange (ETDEWEB)

    Glatzmaier, Greg C.; Rea, J.; Olsen, Michele L.; Oshman, C.; Hardin, C.; Alleman, Jeff; Sharp, J.; Weigand, R.; Campo, D.; Hoeschele, G.; Parilla, Philip A.; Siegel, N. P.; Toberer, Eric S.; Ginley, David S.

    2017-06-27

    We are developing a novel concentrating solar electricity-generating technology that is both modular and dispatchable. Solar ThermoElectricity via Advanced Latent heat Storage (STEALS) uses concentrated solar flux to generate high-temperature thermal energy, which directly converts to electricity via thermoelectric generators (TEGs), stored within a phase-change material (PCM) for electricity generation at a later time, or both allowing for simultaneous charging of the PCM and electricity generation. STEALS has inherent features that drive its cost-competitive scale to be much smaller than current commercial concentrating solar power (CSP) plants. Most obvious is modularity of the solid-state TEG, which favors smaller scales in the kilowatt range as compared to CSP steam turbines, which are minimally 50 MWe for commercial power plants. Here, we present techno-economic and market analyses that show STEALS can be a cost-effective electricity-generating technology with particular appeal to small-scale microgrid applications. We evaluated levelized cost of energy (LCOE) for STEALS and for a comparable photovoltaic (PV) system with battery storage. For STEALS, we estimated capital costs and the LCOE as functions of the type of PCM including the use of recycled aluminum alloys, and evaluated the cost tradeoffs between plasma spray coatings and solution-based boron coatings that are applied to the wetted surfaces of the PCM subsystem. We developed a probabilistic cost model that accounts for uncertainties in the cost and performance inputs to the LCOE estimation. Our probabilistic model estimated LCOE for a 100-kWe STEALS system that had 5 hours of thermal storage and 8-10 hours of total daily power generation. For these cases, the solar multiple for the heliostat field varied between 1.12 and 1.5. We identified microgrids as a likely market for the STEALS system. We characterized microgrid markets in terms of nominal power, dispatchability, geographic location, and

  2. Solar thermoelectricity via advanced latent heat storage: A cost-effective small-scale CSP application

    Science.gov (United States)

    Glatzmaier, G. C.; Rea, J.; Olsen, M. L.; Oshman, C.; Hardin, C.; Alleman, J.; Sharp, J.; Weigand, R.; Campo, D.; Hoeschele, G.; Parilla, P. A.; Siegel, N. P.; Toberer, E. S.; Ginley, D. S.

    2017-06-01

    We are developing a novel concentrating solar electricity-generating technology that is both modular and dispatchable. Solar ThermoElectricity via Advanced Latent heat Storage (STEALS) uses concentrated solar flux to generate high-temperature thermal energy, which directly converts to electricity via thermoelectric generators (TEGs), stored within a phase-change material (PCM) for electricity generation at a later time, or both allowing for simultaneous charging of the PCM and electricity generation. STEALS has inherent features that drive its cost-competitive scale to be much smaller than current commercial concentrating solar power (CSP) plants. Most obvious is modularity of the solid-state TEG, which favors smaller scales in the kilowatt range as compared to CSP steam turbines, which are minimally 50 MWe for commercial power plants. Here, we present techno-economic and market analyses that show STEALS can be a cost-effective electricity-generating technology with particular appeal to small-scale microgrid applications. We evaluated levelized cost of energy (LCOE) for STEALS and for a comparable photovoltaic (PV) system with battery storage. For STEALS, we estimated capital costs and the LCOE as functions of the type of PCM including the use of recycled aluminum alloys, and evaluated the cost tradeoffs between plasma spray coatings and solution-based boron coatings that are applied to the wetted surfaces of the PCM subsystem. We developed a probabilistic cost model that accounts for uncertainties in the cost and performance inputs to the LCOE estimation. Our probabilistic model estimated LCOE for a 100-kWe STEALS system that had 5 hours of thermal storage and 8-10 hours of total daily power generation. For these cases, the solar multiple for the heliostat field varied between 1.12 and 1.5. We identified microgrids as a likely market for the STEALS system. We characterized microgrid markets in terms of nominal power, dispatchability, geographic location, and

  3. Models comparative study for heat storage in fixed beds; Estudo comparativo de modelos para armazenamento de calor em leitos fixos

    Energy Technology Data Exchange (ETDEWEB)

    Stuginski Junior, Rubens

    1991-07-01

    This work presents comparative results of a numerical investigation of four possible models for the prediction of thermal performance of fixed bed storage units and their thermal design. These models includes Schumann's model, the radial dispersion model, a model that include both axial heat conduction in the fluid phase and admits thermal gradient in the solids particles and finally a two dimensional single phase model. For each of these models a computer code was written and tested to evaluate the computing time of same data and analyze any other computational problems. The tests of thermal performance included particle size, porosity, particle material, flow rate, inlet temperature and heat losses form tank walls and extremities. Dynamics behaviour of the storage units due to transient variation in either flow rate or inlet temperature was also investigated. The results presented include temperature gradients, pressure drop and heat storage. The results obtained are very useful for analysis and design of fixed bed storage units. (author)

  4. Chlorophylls and carotenoids of kiwifruit puree are affected similarly or less by microwave than by conventional heat processing and storage.

    Science.gov (United States)

    Benlloch-Tinoco, María; Kaulmann, Anouk; Corte-Real, Joana; Rodrigo, Dolores; Martínez-Navarrete, Nuria; Bohn, Torsten

    2015-11-15

    The impact of microwave (1000 W - 340 s) and conventional heat (97 °C - 30s) pasteurisation and storage (4, 10, 22 °C for up to 63 d) on total and individual carotenoids and chlorophylls in kiwifruit puree was evaluated. Bioaccessibility of carotenoids, before and after pasteurisation and storage, was also studied. Microwaves and conventional heating led to marked changes in the chlorophyll (42-100% losses) and carotenoid (62-91% losses) content. First- and second-order kinetics appropriately explained the degradation of total carotenoids and chlorophylls over time, respectively. Pasteurised samples showed significantly (p chlorophyll stability to a greater extent than conventional heating (k = 0.0015-0.034100 g mg(-1) day(-1) at 4-22 °C). Bioaccessibility of carotenoids remained (p < 0.05) unaffected by processing and storage. These results highlighted that the pigment composition of microwaved kiwifruit was more similar to that of the fresh fruit and better preserved during storage.

  5. Response surface method optimization of V-shaped fin assisted latent heat thermal energy storage system during discharging process

    Directory of Open Access Journals (Sweden)

    Sina Lohrasbi

    2016-09-01

    Full Text Available Latent Heat Thermal Energy Storage Systems (LHTESS containing Phase Change Material (PCM are used to establish balance between energy supply and demand. PCMs have high latent heat but low thermal conductivity, which affects their heat transfer performance. In this paper, a novel fin array has been optimized by multi-objective Response Surface Method (RSM based on discharging process of PCM, and then this fin configuration is applied on LHTESS, and comparison between full discharging time by applying this fin array and LHTESS with other fin structures has been carried out. The employed numerical method in this paper is Standard Galerkin Finite Element Method. Adaptive grid refinement is used to solve the equations. Since the enhancement technique, which has been employed in the present study reduces the employed PCM mass, maximum energy storage capacity variations have been considered. Therefore phase change expedition and maximum energy storage capacity have been considered as the objectives of optimization and the importance of second objective is indicated which is proposed as the novelty here. Results indicate that considering maximum energy storage capacity as the objective of optimization procedure leads to efficient shape design of LHTESS. Also employing optimized V-shaped fin in LHTESS, expedites discharging process considerably in comparison with the LHTESS without fin.

  6. Study of an electrical heating system with ductless air supply and shape-stabilized PCM for thermal storage

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Kunping; Zhang, Yinping; Di, Hongfa [Department of Building Science, Tsinghua University, Beijing 100084 (China); Yang, Rui [Department of Chemical Engineering, Tsinghua University, Beijing 100084 (China)

    2007-07-15

    A kind of electrical floor heating system with a shape-stabilized phase change material (PCM) which has been studied at Tsinghua University in our previous studies, can provide space heating during the whole day and can be controlled conventionally. However, this is not suitable for office buildings where no space heating is needed at night. The effective control is very important for the heating system in such buildings. In this paper, we studied a kind of new electrical floor heating system with ductless air supply and shape-stabilized PCM for thermal storage in order to overcome the shortcomings of the passive under-floor electric heating system with thermal storage. In this paper, we investigated its thermal performance by experiments and simulation, calculated the effects of various factors and discussed the application feasibility in different climate regions. The results show that the total electrical energy consumption was shifted from the peak period to the off-peak period, which would provide significant economic benefits because of the different day and night electricity tariffs. The system can be designed by choosing PCM with proper melting temperature and be controlled by varying velocity of air supply in different conditions. (author)

  7. Melting and solidification characteristics of a mixture of two types of latent heat storage material in a vessel

    Science.gov (United States)

    Yu, JikSu; Horibe, Akihiko; Haruki, Naoto; Machida, Akito; Kato, Masashi

    2016-11-01

    In this study, we investigated the fundamental melting and solidification characteristics of mannitol, erythritol, and their mixture (70 % by mass mannitol: 30 % by mass erythritol) as potential phase-change materials (PCMs) for latent heat thermal energy storage systems, specifically those pertaining to industrial waste heat, having temperatures in the range of 100-250 °C. The melting point of erythritol and mannitol, the melting peak temperature of their mixture, and latent heat were measured using differential scanning calorimetry. The thermal performance of the mannitol mixture was determined during melting and solidification processes, using a heat storage vessel with a pipe heat exchanger. Our results indicated phase-change (fusion) temperatures of 160 °C for mannitol and 113 and 150 °C for the mannitol mixture. Nondimensional correlation equations of the average heat transfer during the solidification process, as well as the temperature and velocity efficiencies of flowing silicon oil in the pipe and the phase-change material (PCM), were derived using several nondimensional parameters.

  8. Thermal properties and thermal reliability of eutectic mixtures of some fatty acids as latent heat storage materials

    Energy Technology Data Exchange (ETDEWEB)

    Ahmet Sarl; Hayati Sarl; Adem Onal [Gaziosmanpasa University, Tokat (Turkey). Dept. of Chemistry

    2004-02-01

    The present study deals with two subjects. The first one is to determine the thermal properties of lauric acid (LA)-stearic acid (SA), myristic acid (MA)-palmitic acid (PA) and palmitic acid (PA)-stearic acid (SA) eutectic mixtures as latent heat storage material. The properties were measured by the differential scanning calorimetry (DSC) analysis technique. The second one is to study the thermal reliability of these materials in view of the change in their melting temperatures and latent heats of fusion with respect to repeated thermal cycles. For this aim, the eutectic mixtures were subjected to 360 repeated melt/freeze cycles, and their thermal properties were measured after 0, 90,1 80 and 360 thermal cycles by the technique of DSC analysis. The DSC thermal analysis results show that the binary systems of LA-SA in the ratio of 75.5:24.5 wt.%, MA-PA in the ratio of 58:42 wt.% and PA-SA in the ratio of 64.2:35.8 wt.% form eutectic mixtures with melting temperatures of 37.0, 42.60 and 52.30{sup o}C and with latent heats of fusion of 182.7, 169.7 and 181.7 J g{sup -1}, respectively. These thermal properties make them possible for heat storage in passive solar heating applications with respect to climate conditions. The accelerated thermal cycle tests indicate that the changes in the melting temperatures and latent heats of fusion of the studied eutectic mixtures are not regular with increasing number of thermal cycles. However, these materials, latent heat energy storage materials, have good thermal reliability in terms of the change in their thermal properties with respect to thermal cycling for about a one-year utility period. (author)

  9. 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

  10. The roles of thermal insulation and heat storage in the energy performance of the wall materials: a simulation study.

    Science.gov (United States)

    Long, Linshuang; Ye, Hong

    2016-04-07

    A high-performance envelope is the prerequisite and foundation to a zero energy building. The thermal conductivity and volumetric heat capacity of a wall are two thermophysical properties that strongly influence the energy performance. Although many case studies have been performed, the results failed to give a big picture of the roles of these properties in the energy performance of an active building. In this work, a traversal study on the energy performance of a standard room with all potential wall materials was performed for the first time. It was revealed that both heat storage materials and insulation materials are suitable for external walls. However, the importances of those materials are distinct in different situations: the heat storage plays a primary role when the thermal conductivity of the material is relatively high, but the effect of the thermal insulation is dominant when the conductivity is relatively low. Regarding internal walls, they are less significant to the energy performance than the external ones, and they need exclusively the heat storage materials with a high thermal conductivity. These requirements for materials are consistent under various climate conditions. This study may provide a roadmap for the material scientists interested in developing high-performance wall materials.

  11. Heat storage properties of organic phase-change materials confined in the nanospace of mesoporous SBA-15 and CMK-3.

    Science.gov (United States)

    Kadoono, Tomosuke; Ogura, Masaru

    2014-03-28

    A novel type of material encapsulating phase-change materials (PCMs) is reported concerning their implication for use as thermal energy storage devices. The composites of siliceous SBA-15 or carbonaceous CMK-3 mesoporous assemblies and organic PCMs could be used to make leak-free devices that retain their capabilities over many thermal cycles for heat storage/release. A confinement effect was observed that alters the thermal properties of the encapsulated PCM, especially in CMK-3 without any similar effects in other carbon materials.

  12. Heat-energy storage through semi-opened circulation into low-permeability hard-rock aquifers

    Science.gov (United States)

    Pettenati, Marie; Bour, Olivier; Ausseur, Jean-Yves; de Dreuzy, Jean-Raynald; de la Bernardie, Jérôme; Chatton, Eliot; Lesueur, Hervé; Bethencourt, Lorine; Mougin, Bruno; Aquilina, Luc; Koch, Florian; Dewandel, Benoit; Boisson, Alexandre; Mosser, Jean-François; Pauwels, Hélène

    2016-04-01

    In low-permeability environments, the solutions of heat storage are still limited to the capacities of geothermal borehole heat exchangers. The ANR Stock-en-Socle project explores the possibilities of periodic storage of sensitive heat1 in low-permeability environments that would offer much better performance than that of borehole heat exchangers, especially in terms of unit capacity. This project examines the storage possibilities of using semi-open water circulation in typically a Standing Column Well (SCW), using the strong heterogeneity of hard-rock aquifers in targeting the least favorable areas for water resources. To solve the main scientific issues, which include evaluating the minimum level of permeability required around a well as well as its evolution through time (increase and decrease) due to water-rock interaction processes, the study is based on an experimental program of fieldwork and modelling for studying the thermal, hydraulic and geochemical processes involved. This includes tracer and water-circulation tests by injecting hot water in different wells located in distinct hard-rock settings (i.e. granite and schist) in Brittany, Ploemeur (H+ observatory network) and Naizin. A numerical modelling approach allows studying the effects of permeability structures on the storage and heat-recovery capacities, whereas the modelling of reactive transfers will provide an understanding of how permeability evolves under the influence of dissolution and precipitation. Based on the obtained results, technical solutions will be studied for constructing a well of the SCW type in a low-permeability environment. This work will be completed by a technical and economic feasibility study leading to an investment and operations model. This study aims to describe the suitability of SCW storage for shallow geothermal energy. In order to reach these objectives, Stock-en-Socle is constructed around a public/private partnership between two public research organizations, G

  13. Numerical Simulation on Flow and Heat Transfer Performance of Air-cooler for a Natural Gas Storage Compressor Unit

    Science.gov (United States)

    Liu, Biyuan; Zhang, Feng; Ma, Zenghui; Zheng, Zilong; Feng, Jianmei

    2017-08-01

    Heat transfer efficiency has been a key issue for large size air coolers with the noise reducers used in natural gas storage compressor unit, especially operated in summer with cooling air at a high temperature. The 3-D numerical simulation model of the whole air cooler was established to study the flow field characteristic with different inlet and outlet structures by CFD software. The system pressure loss distributions were calculated. The relationship was obtained among heat exchange efficiency, resistance loss, and the structure of air cooler, the results presented some methods to improve cooling air flow rate and heat exchange efficiency. Based on the results, some effective measures were proposed to improve heat exchanger efficiency and were implemented in the actual operation unit.

  14. On the Utilization of Solar Light and Heat Based on Building Integration---A case study of Qinzhou%基于建筑一体化的太阳能光热利用研究--以钦州市为例

    Institute of Scientific and Technical Information of China (English)

    刘渊; 陈晓林

    2015-01-01

    Qinzhou,with annual average daily solar radiation of 12. 66 MJ/ m2 ,enjoys the average amount of solar energy. Through rational calculation on the data of roof heat collector and wall-mounted heat collector,this paper presents that the mini-mum collecting area are respectively 2m2 和 3m2 . According to the best space usage of flat roof and pitched roof,the solar thermal systems are adapted to the 12th floor and the 15th floor. Therefore,the apartments on higher floors should be under careful consid-eration for the choice of solar energy to the actual needs and situation.%钦州市属于太阳能源一般区,太阳能年平均日辐射量为12.66 MJ/ m2,通过对屋面式和壁挂式两种集热器集热面积的合理计算,得出屋面式和壁挂式的集热器最小集热面积分别为2m2和3 m2。按平屋面和坡屋面最理想的利用空间计算,太阳能光热系统所能满足的楼层分别为12层和15层,高于12层和15层的住户应根据需求及实际情况慎重考虑是否选用太阳能与建筑一体化技术。

  15. Multi-criteria assesment of building integrated photovoltaics

    OpenAIRE

    Violeta Motuzienė; Kęstutis Valančius

    2015-01-01

    To make reasonable solutions concerning integration of PV into the façade, complex assessment must be performed at the design stage of the building, taking into account all benefits and losses. The paper presents multi-criteria analysis of semi-transparent BIPV. It is based on 4 criteria: energy, ecology, economy, comfort – 3e+c. Results show that because of twice lower solar heat gains, PV window enables to save almost half of cooling energy, it also significantly improves thermal comfort. T...

  16. New Carbon-Based Porous Materials with Increased Heats of Adsorption for Hydrogen Storage

    Energy Technology Data Exchange (ETDEWEB)

    Snurr, Randall Q.; Hupp, Joseph T.; Kanatzidis, Mercouri G.; Nguyen, SonBinh T.

    2014-11-03

    the optimal isosteric heat of adsorption (Qst) for maximum hydrogen delivery using MOFs is approximately 20 kJ/mol. If the heat of adsorption is too low, little hydrogen is adsorbed. If the heat of adsorption is too high, it is difficult to recover the hydrogen at the desorption pressure. The results supported the major premise of this project that increasing Qst for MOFs with large surface areas is required to attain current hydrogen storage targets in terms of deliverable capacity.

  17. Optimal Design of Cogeneration Systems in Industrial Plants Combined with District Heating/Cooling and Underground Thermal Energy Storage

    Directory of Open Access Journals (Sweden)

    Vincenzo Dovì

    2011-12-01

    Full Text Available Combined heat and power (CHP systems in both power stations and large plants are becoming one of the most important tools for reducing energy requirements and consequently the overall carbon footprint of fundamental industrial activities. While power stations employ topping cycles where the heat rejected from the cycle is supplied to domestic and industrial consumers, the plants that produce surplus heat can utilise bottoming cycles to generate electrical power. Traditionally the waste heat available at high temperatures was used to generate electrical power, whereas energy at lower temperatures was either released to the environment or used for commercial or domestic heating. However the introduction of new engines, such as the ones using the organic Rankine cycle, capable of employing condensing temperatures very close to the ambient temperature, has made the generation of electrical power at low temperatures also convenient. On the other hand, district heating is becoming more and more significant since it has been extended to include cooling in the warm months and underground storage of thermal energy to cope with variable demand. These developments imply that electric power generation and district heating/cooling may become alternative and not complementary solutions for waste energy of industrial plants. Therefore the overall energy management requires the introduction of an optimisation algorithm to select the best strategy. In this paper we propose an algorithm for the minimisation of a suitable cost function, for any given variable heat demand from commercial and domestic users, with respect to all independent variables, i.e., temperatures and flowrates of warm fluid streams leaving the plants and volume and nature of underground storage. The results of the preliminary process integration analysis based on pinch technology are used in this algorithm to provide bounds on the values of temperatures.

  18. Eutectic mixtures of some fatty acids for latent heat storage: Thermal properties and thermal reliability with respect to thermal cycling

    Energy Technology Data Exchange (ETDEWEB)

    Sari, Ahmet [Department of Chemistry, Gaziosmanpasa University, 60240 Tokat (Turkey)]. E-mail: asari@gop.edu.tr

    2006-06-15

    Accelerated thermal cycle tests have been conducted to study the change in melting temperatures and latent heats of fusion of the eutectic mixtures of lauric acid (LA)-myristic acid (MA), lauric acid (LA)-palmitic acid (PA) and myristic acid (MA)-stearic acid (SA) as latent heat storage materials. The thermal properties of these materials were determined by the differential scanning calorimetry (DSC) analysis method. The thermal reliability of the eutectic mixtures after melt/freeze cycles of 720, 1080 and 1460 was also evaluated using the DSC curves. The accelerated thermal cycle tests indicate that the melting temperatures usually tend to decrease, and the variations in the latent heats of fusion are irregular with increasing number of thermal cycles. Moreover, the probable reasons for the change in thermal properties of the eutectic mixtures after repeated thermal cycles were investigated. Fourier Transform Infrared (FT-IR) spectroscopic analysis indicates that the accelerated melt/freeze processes do not cause any degradation in the chemical structure of the mixtures. The change in thermal properties of the eutectic mixtures with increasing number of thermal cycles is only because of the presence of certain amounts of impurities in the fatty acids used in their preparation. It is concluded that the tested eutectic mixtures have reasonable thermal properties and thermal reliability as phase change materials (PCMs) for latent heat storage in any solar heating applications that include a four year utilization period.

  19. A method for determination of heat storage capacity of the mold materials using a differential thermal analysis

    Science.gov (United States)

    Ol'khovik, E.

    2016-04-01

    The article proposes a method for determining of the heat storage capacity of the mould materials. Modern materials for mouldsare made using a variety of technologies, and the manufacturers of binders and additives ensure thermal properties of certain materials only when using a certain recipe. In practice, for management of the casting solidification process (creation of the volume or directed mode) it is favorable to apply various technological methods, including modification of one of the important properties of the casting mould, which is heat storage capacity. A rather simple technique based on the application of the differential thermal analysis was developed for its experimental definition. The obtained data showed a possibility of industrial application of the method.

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

    Science.gov (United States)

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

    2016-09-01

    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. In this study, we apply a GGA-DFT to gain insight into the various hydrates of CaMg2Cl6. We have obtained the structural properties, atomic charges and vibrational frequencies of CaMg2Cl6 hydrates. The entropic contribution and the enthalpy change are quantified from ground state energy and harmonic frequencies. Subsequently, the change in the Gibbs free energy of thermolysis was obtained under a wide range of temperature and pressure. The equilibrium product concentration of thermolysis can be used to design the seasonal heat storage system under different operating conditions.

  1. The effect of heat shrink treatment and storage temperature on the time of onset of "blown pack" spoilage.

    Science.gov (United States)

    Moschonas, Galatios; Bolton, Declan J; Sheridan, James J; McDowell, David A

    2011-02-01

    This study determined the effects of (a) the short "heat shrink" treatment frequently applied to vacuum packed meats within normal commercial production, and (b) chill holding storage temperature, on the subsequent time to onset (TTO) of "blown pack" spoilage (BPS). Beef or lamb steaks were inoculated with 10³ CFU/cm² of spore suspensions of five gas producing clostridia, vacuum packed (VP) and treated as follows: no heat, 50°C/15 s, 70°C/10 s or 90°C/3 s. Samples were stored at -1.5, 1 or 4°C and examined daily to determine TTO of BPS. For each strain, pack treatment and storage temperature had significant (Pshrinking, and by storing VP meats at lower temperatures (e.g. -1.5°C).

  2. PERFORMANCE OF A FORCED CONVECTION SOLAR DRIER INTEGRATED WITH GRAVEL AS HEAT STORAGE MATERIAL FOR CHILI DRYING

    Directory of Open Access Journals (Sweden)

    M. MOHANRAJ

    2009-09-01

    Full Text Available An indirect forced convection solar drier integrated with different sensible heat storage maternal has been developed and tested its performance for drying chili under the metrological conditions of Pollachi, India. The system consists of a flat plate solar air heater with heat storage unit, a drying chamber and a centrifugal blower. Drying experiments have been performed at an air flow rate of 0.25 kg/s. Drying of chili in a forced convection solar drier reduces the moisture content from around 72.8% (wet basis to the final moisture content about 9.1% in 24 h. Average drier efficiency was estimated to be about 21%. The specific moisture extraction rate was estimated to be about 0.87 kg/kWh.

  3. Food matrices and cell conditions influence survival of Lactobacillus rhamnosus GG under heat stresses and during storage.

    Science.gov (United States)

    Endo, Akihito; Teräsjärvi, Johanna; Salminen, Seppo

    2014-03-17

    The present study evaluated impact of moisture content and cell conditions on survival of probiotic strain, Lactobacillus rhamnosus GG, under lethal heat stresses and during long-term storage using freeze-dried cells and oils as matrices. Viable cell counts of freeze-dried L. rhamnosus GG cells suspended in oils had only 1-log-reduction after 5min at 80°C and approximately 3-log-reduction after 20min, while no or very few viable cells were recorded for freeze dried cells suspended in buffer and cultured cells in oils. Surprisingly, freeze-dried cells suspended in oils still contained 4.3 to 6.7logCFU/ml after 5min at 95°C. Long-term storage study indicated that freeze-dried cells suspended in oils kept viable conditions for 4months, and a loss of the viability was only 0.3 to 0.6logCFU/ml. Viable cell counts of cultured cells suspended in oils were not present after 3days to 3months. These results clearly indicate that moisture and cell conditions have a great impact on survival of probiotics under severe heat stress in processing and during long-term storage. Combination of freeze-dried cells and oils as carrier provides beneficial options to preserve viability of probiotics in food processes and storage.

  4. Effects of Combined Heat and Preservative Treatment on Storability of Ponkan Fruit (Citrus reticulata Blanco cv. Ponkan during Postharvest Storage

    Directory of Open Access Journals (Sweden)

    Dandan Tang

    2017-01-01

    Full Text Available Heat treatment and preservative application have been widely used during postharvest storage of many fresh products, but the effect of their combination on citrus storage has rarely been investigated. In this study, the optimal heat treatment (HT conditions and HT combined with preservative treatment were investigated for Ponkan fruit (Citrus reticulata Blanco cv. Ponkan storage. Results indicated that HT at 55°C for 20 s can significantly reduce the decay rate of Ponkan fruit, and a combination of HT and 25% of the preservative dosage used in production of iminoctadine tris (albesilate, 2,4-dichlorophenoxyacetic acid, and imazalil significantly reduced the decay rate without affecting fruit quality. In addition, the increased fiber contents in fruit receiving the HT combined with preservative treatments may be a response preventing fungus infection and enhancing fruit storability and resistance. The above results suggested that the combination of HT and 25% of the preservative production dosage was optimal for controlling Ponkan fruit decay during storage.

  5. Energy Optimization for Transcritical CO2 Heat Pump for Combined Heating and Cooling and Thermal Storage Applications

    DEFF Research Database (Denmark)

    Do Carmo, Carolina Madeira Ramos; Blarke, Morten; Yazawa, Kazuaki

    2012-01-01

    A transcritical heat pump (THP) cycle using carbon dioxide (CO2) as the refrigerant is known to feature an excellent coefficient of performance (COP) as a thermodynamic system. Using this feature, we are designing and building a system that combines a water-to-water CO2 heat pump with both hot an...

  6. Heat transfer and parametric studies of an encapsulated phase change material based cool thermal energy storage system

    Institute of Scientific and Technical Information of China (English)

    CHERALATHAN M.; VELRAJ R.; RENGANARAYANAN S.

    2006-01-01

    This work investigates the transient behaviour of a phase change material based cool thermal energy storage (CTES)system comprised of a cylindrical storage tank filled with encapsulated phase change materials (PCMs) in spherical container integrated with an ethylene glycol chiller plant. A simulation program was developed to evaluate the temperature histories of the heat transfer fluid (HTF) and the phase change material at any axial location during the charging period. The results of the model were validated by comparison with experimental results of temperature profiles of HTF and PCM. The model was also used to investigate the effect of porosity, Stanton number, Stefan number and Peclet number on CTES system performance. The results showed that increase in porosity contributes to a higher rate of energy storage. However, for a given geometry and heat transfer coefficient, the mass of PCM charged in the unit decreases as the increase in porosity. The St number as well as the Ste number is also influential in the performance of the unit. The model is a convenient and more suitable method to determine the heat transfer characteristics of CTES system. The results reported are much useful for designing CTES system.

  7. Preparation, Characterization and Thermal Properties of Paraffin Wax – Expanded Perlite Form-Stable Composites for Latent Heat Storage

    Directory of Open Access Journals (Sweden)

    Tugba GURMEN OZCELIK

    2017-02-01

    Full Text Available In this study, form-stable composite phase change materials (PCM for latent heat storage were prepared by impregnating paraffin wax into the pores of the expanded perlite (EP. The characterization of the composite PCMs was performed by FTIR, TGA, SEM and DSC analysis. The melting point and heat of fusion were determined for 25 % paraffin included composite, as 54.3 °C and 94.71 J/g and for 45 % paraffin included composite as 53.6 °C and 106.69 J/g, respectively. The FTIR results showed that there were no chemical reaction between the perlite and paraffin. TGA analysis indicated that both composite PCMs had good thermal stability. SEM images showed that the paraffin was dispersed uniformly into the pores and on the EP surface. There was no leakage and degradation at the composite PCMs after heating and cooling cycles. According to the results, both prepared composites showed good thermal energy storage properties, reliability and stability. All results suggested that the presented form- stable composite PCMs has great potential for thermal energy storage applications.DOI: http://dx.doi.org/10.5755/j01.ms.23.1.13661

  8. Results. Building integrated energy supply; Resultater. Bygningsintegreret energiforsyning

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Rasmus L.; Noergaard, J.; Daniels, O.; Justesen, R.O.

    2011-08-15

    In the future, buildings will not only act as consumers of energy but as producers as well. For these ''prosumers'', energy production by use of solar panels, photovoltaics and heat pumps etc will be essential. The objective of this project was to find the most optimal combinations of building insulation and use of renewable energy sources in existing buildings in terms of economics and climate impacts. Five houses were analyzed based on different personal load, consumption profiles, solar orientation and proposed building envelope improvements and use of combinations of renewable energy systems. The analysis was conducted by making a large number of simulations of which the best combinations were selected. The final result takes form of a single top-50 list with the best combinations of energy systems according to CO{sub 2} emission, energy consumption and economics. The present report contains the conclusions of and comments on the project's results. (ln)

  9. Multi-criteria assesment of building integrated photovoltaics

    Directory of Open Access Journals (Sweden)

    Violeta Motuzienė

    2015-10-01

    Full Text Available To make reasonable solutions concerning integration of PV into the façade, complex assessment must be performed at the design stage of the building, taking into account all benefits and losses. The paper presents multi-criteria analysis of semi-transparent BIPV. It is based on 4 criteria: energy, ecology, economy, comfort – 3e+c. Results show that because of twice lower solar heat gains, PV window enables to save almost half of cooling energy, it also significantly improves thermal comfort. Total primary energy demand of the office after application of PV drops from 171 kWh/m2 to 96 kWh/m2. Multi-criteria analysis shows that office with BIPV is more sustainable than the one with transparent window.

  10. Experimental Study on Specific Heat of Concrete at High Temperatures and Its Influence on Thermal Energy Storage

    Directory of Open Access Journals (Sweden)

    Jianwen Pan

    2016-12-01

    Full Text Available Using concrete as a thermal energy storage (TES material is a promising option for large-scale solar-thermal resource development and utilization. Specific heat is one of the most important characteristics for TES performance. In this paper, the half-open dynamic method based on the mixing principle is proposed and applied to measure concrete-specific heat at temperatures up to 600 °C. Measurement of the specific heat of corundum ceramic (99% Al2O3 is first performed, and the test results illustrate the accuracy and efficiency of the proposed test method. Furthermore, concrete-specific heat tests are carried out at high temperatures. It found that the specific heat increases as the temperature rises, especially, linearly in the range of 300–600 °C, in which the concrete TES module is expected to be in operation. Finally, the effect of concrete-specific heat changes with temperature on its TES capacity is investigated, demonstrating that specific heat is of great significance for concrete TES design for concentrating solar power.

  11. Calculation steps. Building integrated energy supply; Beregningsgang. Bygningsintegreret energiforsyning

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, Rasmus L.; Noergaard, J.; Daniels, O.; Justesen, R.O.

    2011-08-15

    In the future, buildings will not only act as consumers of energy but as producers as well. For these ''prosumers'', energy production by use of solar panels, photovoltaics and heat pumps etc will be essential. The objective of this project was to find the most optimal combinations of building insulation and use of renewable energy sources in existing buildings in terms of economics and climate impacts. Five houses were analyzed based on different personal load, consumption profiles, solar orientation and proposed building envelope improvements and use of combinations of renewable energy systems. The analysis was conducted by making a large number of simulations. The present report describes the applied simulation models, and explains the results and computer codes. The parameter variations are described for each house as well as the common calculation steps for each house. The results are presented in case sheets, as performance graphs, and top-50 lists for the best cases regarding CO{sub 2} emission, energy consumption and economics. (ln)

  12. New Carbon-Based Porous Materials with Increased Heats of Adsorption for Hydrogen Storage

    Energy Technology Data Exchange (ETDEWEB)

    Snurr, Randall Q.; Hupp, Joseph T.; Kanatzidis, Mercouri G.; Nguyen, SonBinh T.

    2014-11-03

    Hydrogen fuel cell vehicles are a promising alternative to internal combustion engines that burn gasoline. A significant challenge in developing fuel cell vehicles is to store enough hydrogen on-board to allow the same driving range as current vehicles. One option for storing hydrogen on vehicles is to use tanks filled with porous materials that act as “sponges” to take up large quantities of hydrogen without the need for extremely high pressures. The materials must meet many requirements to make this possible. This project aimed to develop two related classes of porous materials to meet these requirements. All materials were synthesized from molecular constituents in a building-block approach, which allows for the creation of an incredibly wide variety of materials in a tailorable fashion. The materials have extremely high surface areas, to provide many locations for hydrogen to adsorb. In addition, they were designed to contain cations that create large electric fields to bind hydrogen strongly but not too strongly. Molecular modeling played a key role as a guide to experiment throughout the project. A major accomplishment of the project was the development of a material with record hydrogen uptake at cryogenic temperatures. Although the ultimate goal was materials that adsorb large quantities of hydrogen at room temperature, this achievement at cryogenic temperatures is an important step in the right direction. In addition, there is significant interest in applications at these temperatures. The hydrogen uptake, measured independently at NREL was 8.0 wt %. This is, to the best of our knowledge, the highest validated excess hydrogen uptake reported to date at 77 K. This material was originally sketched on paper based on a hypothesis that extended framework struts would yield materials with excellent hydrogen storage properties. However, before starting the synthesis, we used molecular modeling to assess the performance of the material for hydrogen uptake

  13. 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

  14. Effects of Pressure, Temperature, Treatment Time, and Storage on Rheological, Textural, and Structural Properties of Heat-Induced Chickpea Gels

    Science.gov (United States)

    Alvarez, María Dolores; Fuentes, Raúl; Canet, Wenceslao

    2015-01-01

    Pressure-induced gelatinization of chickpea flour (CF) was studied in combination with subsequent temperature-induced gelatinization. CF slurries (with 1:5 flour-to-water ratio) and CF in powder form were treated with high hydrostatic pressure (HHP), temperature (T), and treatment time (t) at three levels (200, 400, 600 MPa; 10, 25, 50 °C; 5, 15, 25 min). In order to investigate the effect of storage (S), half of the HHP-treated CF slurries were immediately analyzed for changes in oscillatory rheological properties under isothermal heating at 75 °C for 15 min followed by cooling to 25 °C. The other half of the HHP-treated CF slurries were refrigerated (at 4 °C) for one week and subsequently analyzed for changes in oscillatory properties under the same heating conditions as the unrefrigerated samples. HHP-treated CF in powder form was analyzed for changes in textural properties of heat-induced CF gels under isothermal heating at 90 °C for 5 min and subsequent cooling to 25 °C. Structural changes during gelatinization were investigated using microscopy. Pressure had a more significant effect on rheological and textural properties, followed by T and treatment t (in that order). Gel aging in HHP-treated CF slurries during storage was supported by rheological measurements. PMID:28231191

  15. Effects of Pressure, Temperature, Treatment Time, and Storage on Rheological, Textural, and Structural Properties of Heat-Induced Chickpea Gels

    Directory of Open Access Journals (Sweden)

    María Dolores Alvarez

    2015-04-01

    Full Text Available Pressure-induced gelatinization of chickpea flour (CF was studied in combination with subsequent temperature-induced gelatinization. CF slurries (with 1:5 flour-to-water ratio and CF in powder form were treated with high hydrostatic pressure (HHP, temperature (T, and treatment time (t at three levels (200, 400, 600 MPa; 10, 25, 50 °C; 5, 15, 25 min. In order to investigate the effect of storage (S, half of the HHP-treated CF slurries were immediately analyzed for changes in oscillatory rheological properties under isothermal heating at 75 °C for 15 min followed by cooling to 25 °C. The other half of the HHP-treated CF slurries were refrigerated (at 4 °C for one week and subsequently analyzed for changes in oscillatory properties under the same heating conditions as the unrefrigerated samples. HHP-treated CF in powder form was analyzed for changes in textural properties of heat-induced CF gels under isothermal heating at 90 °C for 5 min and subsequent cooling to 25 °C. Structural changes during gelatinization were investigated using microscopy. Pressure had a more significant effect on rheological and textural properties, followed by T and treatment t (in that order. Gel aging in HHP-treated CF slurries during storage was supported by rheological measurements.

  16. 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.)

  17. Analysis of Influence of Heat Insulation on the Thermal Regime of Storage Tanks with Liquefied Natural Gas

    Directory of Open Access Journals (Sweden)

    Maksimov Vyacheslav I.

    2016-01-01

    Full Text Available Is numerically investigated the process of convective heat transfer in the reservoirs of liquefied natural gas (LNG. The regimes of natural convection in a closed rectangular region with different intensity of heat exchange at the external borders are investigated. Is solved the time-dependent system of energy and Navier-Stokes equations in the dimensionless variables “vorticity – the stream function”. Are obtained distributions of the hydrodynamic parameters and temperatures, that characterize basic regularities of the processes. The special features of the formation of circulation flows are isolated and the analysis of the temperature distribution in the solution region is carried out. Is shown the influence of geometric characteristics and intensity of heat exchange on the outer boundaries of reservoir on the temperature field in the LNG storage.

  18. 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)

  19. Numerical performance study of paraffin wax dispersed with alumina in a concentric pipe latent heat storage system

    Directory of Open Access Journals (Sweden)

    Valan Arasu Amirtham

    2013-01-01

    Full Text Available Latent heat energy storage systems using paraffin wax could have lower heat transfer rates during melting/freezing processes due to its inherent low thermal conductivity. The thermal conductivity of paraffin wax can be enhanced by employing high conductivity materials such as alumina (Al2O3. A numerical analysis has been carried out to study the performance enhancement of paraffin wax with nanoalumina (Al2O3 particles in comparison with simple paraffin wax in a concentric double pipe heat exchanger. Numerical analysis indicates that the charge-discharge rates of thermal energy can be greatly enhanced using paraffin wax with alumina as compared with a simple paraffin wax as PCM.

  20. An analysis of a packed bed latent heat thermal energy storage system using PCM capsules. Numerical investigation

    Energy Technology Data Exchange (ETDEWEB)

    Felix Regin, A.; Solanki, S.C.; Saini, J.S. [Mechanical and Industrial Engineering Department, Indian Institute of Technology Roorkee, Roorkee 247 667, UA (India)

    2009-07-15

    This paper is aimed at analyzing the behavior of a packed bed latent heat thermal energy storage system. The packed bed is composed of spherical capsules filled with paraffin wax as PCM usable with a solar water heating system. The model developed in this study uses the fundamental equations similar to those of Schumann, except that the phase change phenomena of PCM inside the capsules are analyzed by using enthalpy method. The equations are numerically solved, and the results obtained are used for the thermal performance analysis of both charging and discharging processes. The effects of the inlet heat transfer fluid temperature (Stefan number), mass flow rate and phase change temperature range on the thermal performance of the capsules of various radii have been investigated. The results indicate that for the proper modeling of performance of the system the phase change temperature range of the PCM must be accurately known, and should be taken into account. (author)

  1. 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)

  2. Large-scale building integrated photovoltaics field trial. First technical report - installation phase

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    This report summarises the results of the first eighteen months of the Large-Scale Building Integrated Photovoltaic Field Trial focussing on technical aspects. The project aims included increasing awareness and application of the technology, raising the UK capabilities in application of the technology, and assessing the potential for building integrated photovoltaics (BIPV). Details are given of technology choices; project organisation, cost, and status; and the evaluation criteria. Installations of BIPV described include University buildings, commercial centres, and a sports stadium, wildlife park, church hall, and district council building. Lessons learnt are discussed, and a further report covering monitoring aspects is planned.

  3. Building-Integrated Solar Energy Devices based on Wavelength Selective Films

    Science.gov (United States)

    Ulavi, Tejas

    A potentially attractive option for building integrated solar is to employ hybrid solar collectors which serve dual purposes, combining solar thermal technology with either thin film photovoltaics or daylighting. In this study, two hybrid concepts, a hybrid photovoltaic/thermal (PV/T) collector and a hybrid 'solar window', are presented and analyzed to evaluate technical performance. In both concepts, a wavelength selective film is coupled with a compound parabolic concentrator (CPC) to reflect and concentrate the infrared portion of the solar spectrum onto a tubular absorber. The visible portion of the spectrum is transmitted through the concentrator to either a thin film Cadmium Telluride (CdTe) solar panel for electricity generation or into the interior space for daylighting. Special attention is given to the design of the hybrid devices for aesthetic building integration. An adaptive concentrator design based on asymmetrical truncation of CPCs is presented for the hybrid solar window concept. The energetic and spectral split between the solar thermal module and the PV or daylighting module are functions of the optical properties of the wavelength selective film and the concentrator geometry, and are determined using a Monte Carlo Ray-Tracing (MCRT) model. Results obtained from the MCRT can be used in conjugation with meteorological data for specific applications to study the impact of CPC design parameters including the half-acceptance angle thetac, absorber diameter D and truncation on the annual thermal and PV/daylighting efficiencies. The hybrid PV/T system is analyzed for a rooftop application in Phoenix, AZ. Compared to a system of the same area with independent solar thermal and PV modules, the hybrid PV/T provides 20% more energy, annually. However, the increase in total delivered energy is due solely to the addition of the thermal module and is achieved at an expense of a decrease in the annual electrical efficiency from 8.8% to 5.8% due to shading by

  4. 主动蓄放热-热泵联合加温系统在日光温室的应用%Application of heating system with active heat storage-release and heat pump in solar greenhouse

    Institute of Scientific and Technical Information of China (English)

    孙维拓; 杨其长; 方慧; 张义; 管道平; 卢威

    2013-01-01

    The Chinese solar greenhouse has a unique greenhouse structure that regards solar energy as the main energy source, and has characteristics such as high efficiency, energy saving, and low cost. During a cold winter night, air temperature inside a solar greenhouse is low for crop growth, which would affect crop yield and quality, due to the heat-transfer characteristics and heat capacity limit of the north wall. In recent years, in trying to promote the heat storage capacity of the solar greenhouse, the thought of active heat storage-release came forward. Solar energy is a kind of clean renewable energy, but has intermittent and unstable performance when used for greenhouse heating. Meanwhile, the heat collecting efficiency of the solar thermal collector decreases with an increase in operating temperature. Thus, an active heat storage-release system (AHSRS) is difficult to use to ensure an appropriate temperature for a solar greenhouse in a frigid region or when it encounters weather conditions with weak solar radiation. As an efficient means of raising low-grade energy, the heat pump has been more and more applied to greenhouse heating which can reduce the operating temperature of the AHSRS when used in combination. In order to promote heating performance and stability of the AHSRS and improve air temperature inside a solar greenhouse at night, based on the concept of active heat storage-release, an active heat storage-release associated with heat pump heating system (AHSRHPS) applicable to solar greenhouse heating was designed in the present study. During the day, the solar energy reaching the north wall surface was absorbed by the circulating water and stored in reservoirs when the AHSRS was running. Running the heat pump unit was intended to promote low-grade heat energy and reduce the circulating water temperature which contributes to increasing the heat collecting efficiency of the AHSRS and maximum water temperature of the reservoir. When air temperature

  5. Preliminary design study of a central solar heating plant with seasonal storage at the University of Massachusetts, Amherst

    Science.gov (United States)

    Breger, D. S.; Sunderland, J. E.

    1991-04-01

    This report documents the design development and selection of the final preliminary design of a Central Solar Heating Plant with Seasonal Storage (CSHPSS) for the University of Massachusetts in Amherst (UMass). The effort has been performed by the Department of Mechanical Engineering at UMass under contract with the U.S. Department of Energy. Phase 1 of this project was directed at site selection for the CSHPSS project and was reported earlier. This report focuses on the Phase 2 development of the site conditions and analytical study of project design, performance, and cost. The UMass site presents an excellent opportunity of a CSHPSS project in terms of land availability for a large collector array, a 100 foot deep deposit of soft, saturated clay for seasonal thermal energy storage, and appropriate low temperature heating loads. The project under study represents the first implementation of this solar technology in the United States and results from the International Energy Agency collaboration on CSHPSS since 1979. The preliminary design calls for a large 10,000 m(exp 2) parabolic trough collector array, 70,000 m(exp 3) storage volume in clay with heat transfer through 900 boreholes. Design optimization is based on computer simulations using MINSUN and TRNSYS. The design is expected to provide 95 percent of the 3500 MWh heating and hot water load. A project cost of $3.12 million (plus $240,000 for HVAC load retrofit) is estimated, which provides an annualized cost of $66.2/MWh per unit solar energy delivered. The project will proceed into an engineering phase in Spring 1991.

  6. Annual Collection and Storage of Solar Energy for the Heating of Buildings, Report No. 3. Semi-Annual Progress Report, August 1977 - January 1978.

    Science.gov (United States)

    Beard, J. Taylor; And Others

    This report is part of a series from the Department of Energy on the use of solar energy in heating buildings. Described here is a new system for year around collection and storage of solar energy. This system has been operated at the University of Virginia for over a year. Composed of an underground hot water storage system and solar collection,…

  7. Quercetin and isorhamnetin in sweet and red cultivars of onion (Allium cepa L.) at harvest, after field curing, heat treatment, and storage.

    Science.gov (United States)

    Olsson, Marie E; Gustavsson, Karl-Erik; Vågen, Ingunn M

    2010-02-24

    Effects of heat treatment and storage on quercetin and isorhamnetin content, major and minor components of isorhamnetin, and quercetin glucosides and aglycone, were investigated in onion (Allium cepa L.). The sweet onion 'Recorra' and red onions 'Hyred' and 'Red Baron' were cultivated in the south part of Norway and thereafter stored for eight months. The onions were either not field dried, but stored directly, or field dried and then stored, or field dried and then heat treated before storage. Neither storage nor heat treatment caused any major differences in total flavonol content in the investigated sweet onion as well as in the red onion cultivars. The two major quercetin glucosides differed in their changes in content during storage; quercetin-4'-glucoside did not show any consistent changes during storage in the two red cultivars, independent of treatment, whereas quercetin-3,4'-diglucoside increased significantly by 30 or 51%, respectively, during storage in 'Hyred' and 'Red Baron' in the 24 h heat treated onions. Isorhamnetin-4'-glucoside, which might possibly be of special interest from a human health point of view, was present at 2-3 times higher amount in the sweet onion cultivar than in the two red cultivars. Some of the quercetin glucosides present at lower concentrations, isorhamnetin-3,4'-diglucoside, quercetin-3,7,4'-triglucoside, and quercetin-7,4'-diglucoside, increased during storage in all treatments in both 'Hyred' and 'Red Baron', though sometimes a decrease was found at the end of storage.

  8. A comparison of heat transfer enhancement in medium temperature thermal energy storage heat exchanger using fins and multitubes

    Energy Technology Data Exchange (ETDEWEB)

    Agyenim, Francis [Welsh School of Architecture, Cardiff Univ., Wales (United Kingdom); Eames, Philip [School of Engineering, Univ. of Warwick, Coventry (United Kingdom); Smyth, Mervyn [Centre for Sustainable Technologies, Univ. of Ulster, Newtownabbey (United Kingdom)

    2008-07-01

    Experimental studies using a medium temperature phase change material (PCM) Erythritol, melting point 117.7 C, in a horizontal shell and tube system have been undertaken. The experimental programme investigated the suitability of Erythritol (a sugar based material) to deliver a near constant thermal energy to be used for the hot side of LiBr/water absorption cooling system. Four experimental configurations, consisting a base model with no heat enhancement (control system), systems enhanced with circular and longitudinal fins and a multitube system were studied. Experiments were conducted at the same inlet heat transfer fluid temperature of 140 C and mass flow rate of 30 kg min{sup 1} for the different configurations. The results presented include experimentally determined isotherm plots for the final melt illustrating the heat transfer characteristics of the systems and quantitative information relating to the transient change in temperature during the charging and discharging processes. The experimental results indicate that the multitube system achieved the best charging performance with the shortest melt time due to the presence of convection but showed large subcooling during the discharge process. The presence of longitudinal fins improved the conduction heat transfer significantly during the charging process due to increased heat transfer surface area and also reduced the level of subcooling during the discharge process. The circular finned system showed no significant improvement in melt time and size and as such would not be worthy of further development. (orig.)

  9. CFD Analysis on the Passive Heat Removal by Helium and Air in the Canister of Spent Fuel Dry Storage System

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Do Young; Jeong, Ui Ju; Kim, Sung Joong [Hanyang University, Seoul (Korea, Republic of)

    2016-05-15

    In the current commercial design, the canister of the dry storage system is mainly backfilled with helium gas. Helium gas shows very conductive behavior due to high thermal conductivity and small density change with temperature. However, other gases such as air, argon, or nitrogen are expected to show effective convective behavior. Thus these are also considered as candidates for the backfill gas to provide effective coolability. In this study, to compare the dominant cooling mechanism and effectiveness of cooling between helium gas and air, a computational fluid dynamics (CFD) analysis for the canister of spent fuel dry storage system with backfill gas of helium and air is carried out. In this study, CFD simulations for the helium and air backfilled gas for dry storage system canister were carried out using ANSYS FLUENT code. For the comparison work, two backfilled fluids were modeled with same initial and boundary conditions. The observed major difference can be summarized as follows. - The simulation results showed the difference in dominant heat removal mechanism. Conduction for helium, and convection for air considering Reynolds number distribution. - The temperature gradient inside the fuel assembly showed that in case of air, more effective heat mixing occurred compared to helium.

  10. Heat Transfer of the Concrete Thermal Storage System%混凝土蓄热装置传热研究

    Institute of Scientific and Technical Information of China (English)

    杨小平; 杨晓西; 丁静; 杨敏林; 蒋润花

    2012-01-01

    蓄热装置是太阳能热发电系统中的关键部件之一。对混凝土蓄热装置的传热过程进行了模拟研究,得到了混凝土蓄热器内部的温度等特征参数,并对影响因素进行了分析,结果表明混凝土较大的导热系数有利于提高蓄热温度,导热油进口温度和速度较大的时候,明显提高了换热效果,增加了蓄热装置的蓄热量。%Thermal storage device is one of the key components in the system of a solar thermal power. In this paper, the heat transfer process of a concrete thermal storage is simulated and analyzed. The temperature distribution of the system is obtained and the influence factors are analyzed. When the thermal oil has bigger inlet temperature and velocity, the heat transfer effect is improved significantly, increasing the total thermal storage capacity of the system.

  11. A Study on a Perfaormance of Water-Spray-Type Ice Thermal Energy Storage Vessel with Vertical Heat Exchange Plates

    Science.gov (United States)

    Yoshimura, Kenji; Koyama, Shigeru; Fukuda, Toshihito; Ohba, Hideki

    A system with a water -embedded-type ice storage vessel is widely used because of its simple structure compactness. However, this ice storage vessel has a disadvantage, that is, the melting rate is very small. The use of falling water film seems to be one of promising ways for solving this disadvantage. We have found in our previous study that the use of the falling water film is very effective, especially for high initial water temperatures. In the present study, we examined the melting performance of a falling-water-film-type ice thermal energy storage vessel with practical size, having vertical heat exchange plates. The results obtained are as follows : the quantity of melting ice increases with increase of the water film flow rate, the melting rate decreases with time because ice surface are decreases with time gradually, the heat transfer coefficient of melting increases with increase of the water film flow rate, and the melting rate increases with increase of the water-spray temperature.

  12. A Study on a Performance of Water-Spray-Type Ice Thermal Energy Storage Vessel with Vertical Heat Exchanger Plates

    Science.gov (United States)

    Yoshimura, Kenji; Sasaguchi, Kengo; Fukuda, Toshihito; Koyama, Shigeru

    A system with a water-embedded-trpe ice storage vessel is widely used because of its simple structure and compactness. However, the water-embedded-type ice storage vessel has a disadvantage, that is, the solidification rate is very small. The use of falling water film seems to be one of promising ways for solving this disadvantage. We have found in a previous study that the use of the falling water film is very effective, especially for high initial water temperatures. In the present study, we eexamined the performance of a faling-water-film-type ice thermal energy storage vessel with pratical size, having vertical heat exchanger plates. The ice making performance coefficient, η, increases with time, and it becomes am aximum value of 2.5, after that, it decreases gradually. In order to make ice efficiently, it is necessary to set a flow rate of refrigerant properly and to adjust a difference between the evaporating temperature of refrigerant and the freezing point of water so that the refrigerant evaporates in the heat exchanger plates overall.

  13. Thermodynamic analysis of active heat storage-release associated with heat pump heating system in greenhouse%温室主动蓄放热-热泵联合加温系统热力学分析

    Institute of Scientific and Technical Information of China (English)

    孙维拓; 张义; 杨其长; 方慧; 卢威; 胡永逵

    2014-01-01

    主动蓄放热-热泵联合加温系统加温和节能效果显著,在温室加温领域应用前景广阔,但系统技术参数及工艺仍有待优化。该文通过对系统进行能量平衡和可用能(Exergy)分析,得出系统及各组件的性能系数、可用能损失、损失比和可用能效率,以此为依据对系统进行性能评价和优化。试验结果表明:系统平均1d中集热和保温阶段可用能损失总量为9.77×104 kJ,可用能效率为48.7%;可用能损失最大、可用能效率最低的组件是主动蓄放热装置,其次是热泵装置、循环水泵和蓄热水箱,其可用能损失比分别为78.7%、8.3%、7.7%、5.3%,可用能效率分别为25.6%、38.3%、75.0%、88.2%。就整个系统而言,最需要进行技术优化的是主动蓄放热装置与热泵装置,可用能损失主要由有限温差传热引起,降低传热温差、减少有限温差传热过程以及改进生产工艺是优化的重点。试验期间系统的集热效率为89.0%~100.5%,热泵装置制热性能系数(coefficient of performance,COPHp)达5.48~6.08,性能远远高于传统太阳能热水系统以及水、地源热泵。该研究为温室加温系统性能评价和优化设计提供思路。%Active heat storage-release associated with heat pump heating system (AHSRHPS) has remarkable heating and energy-saving effects, which use the same principle as an indirect-expansion solar heat pump, while allowing the technical parameters and processes to continue to improve. The system in this study was designed and constructed in the experimental glass greenhouse at the Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences. The main objective was to investigate performance evaluation and thermoeconomic analysis of AHSRHPS for greenhouse heating in the winter. This included the exergy loss of the system and components, defining the specific locations and

  14. Saisonal heat storage in mine caverns. Concepts and technical solutions. Second technical report. Saisonal heat storage of solar low temperature heat in mines. Solar mining; Saisonale Waermespeicherung in Grubenraeumen. Konzepte und technische Loesungen. 2. Technischer Fachbericht. Saisonale Speicherung solarer Niedertemperaturwaerme in Bergwerken. Solarenergiebergbau

    Energy Technology Data Exchange (ETDEWEB)

    Eikmeier, B.; Mohr, M.; Unger, H.

    1999-03-01

    The Second Technical Report of the project `Saisonal Storage of Solar Low Temperature Heat in Mines` describes different concepts to realize seasonal storage in mines and suitable district heat systems. The different storage designs and concepts are presented and evaluated in detail. The fundamental differences between the use of a tunnel or a shaft are discussed as well as the storage filling with a fluid or a mineral material. Technical solutions for the integration of a seasonal storage in mines are examined. Different solutions for storage sealing stand for choice. It is shown that the use of air-placed concrete represents a particularly suitable method due to the cost advantages and the flexible operation of the procedure compared with other seal systems. An exemplary system design leads to specific investment costs of 115 DM/m{sup 3} to 300 DM/m{sup 3} for the saisonal storage depending on the boundary conditions (tightness of the surrounding rock, use of available pipework etc.). The latter amount equals the height of the costs payed for the concrete underground tanks in Hamburg-Bramfeld and Friedrichshafen. It is shown that the costs for the use of mines for saisonal storage is comparable to those of existing systems at least; in favorable cases definitely lower costs may be achievable. In any case, a specific evaluation, taking account of local boundary conditions and circumstances, is necessay. On the basis of the boundary conditions below and the situation above ground, many locations in the Ruhr area were estimated concerning their suitability for this project. Favorable locations could be found within almost all coal industry areas. The plan for house buildings at these locations is suitable for the application of a district heat network. Although the examination of seasonal heat storage in mines is not concluded up to now, the presently achieved information indicates very positive results in all sections (i.e. investment costs, technical feasibility

  15. 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.)

  16. Storage of summertime waste heat from electric generating plants for use in wintertime

    Energy Technology Data Exchange (ETDEWEB)

    Smetana, F.P.

    1975-01-01

    As an alternative to the construction of large cooling towers at plants generating electric power, it is suggested that one may wish to consider storing the waste heat produced during the summer until it can be used beneficially the following winter. Keeping tender crops from freezing is one of the most effective ways of using this heat because lower-temperature heat sources will suffice for this purpose than are necessary for space heating human habitations. A 3600 MW plant rejects sufficient heat in 90 days to heat an agricultural area of 2.06 million square meters all winter if sufficient barriers are erected to inhibit horizontal air motion. This heat can be stored in 124 million cubic meters of water. Insulation, construction, and costs of such a tank are treated.

  17. See-through dye-sensitized solar cells: photonic reflectors for tandem and building integrated photovoltaics.

    Science.gov (United States)

    Heiniger, Leo-Philipp; O'Brien, Paul G; Soheilnia, Navid; Yang, Yang; Kherani, Nazir P; Grätzel, Michael; Ozin, Geoffrey A; Tétreault, Nicolas

    2013-10-25

    See-through dye-sensitized solar cells with 1D photonic crystal Bragg reflector photoanodes show an increase in peak external quantum efficiency of 47% while still maintaining high fill factors, resulting in an almost 40% increase in power conversion efficiency. These photoanodes are ideally suited for tandem and building integrated photovoltaics.

  18. Investigation the Advantages of CPV for Building Integrated PV : 28th European Photovoltaic Solar Energy Conference

    NARCIS (Netherlands)

    Sonneveld, Piet; Craats, S. van der; Sparemberger, A.R.; Sahedi, J.V.; Catau, R.G.

    2013-01-01

    The objective of this concept is a significant reduction of energy consumption in greenhouses and buildings with large facades and windows by using available solar energy. The scope of this investigation is to study the advantages of a building integrated CPV system. The basic idea is that a larger

  19. Central solar heating plant with a seasonal storage (CSHPSS) at Heumatt, Zuerich Seebach. Analysis and design by dynamic system simulations

    Energy Technology Data Exchange (ETDEWEB)

    Pahud, D. [Scuola Universitaria Professionale della Svizzera Italiana SUPSI, Dipartimento Ambiente, Costruzioni e Design DACD, Laboratorio Energia Ecologia ed Economia LEEE, Lugano/Trevano (Switzerland)

    2003-10-15

    This report reviews work done at the University of Applied Sciences in Winterthur, Switzerland, on a central storage system for solar heat at a residential building complex in Heumatt, Zurich, Switzerland. Here, dynamic system simulations were used to analyse and design the system. In the Heumatt estate, three apartment buildings were to be retrofitted. Within the framework of this project, a Central Solar Heating Plant with a Seasonal Storage (CSHPSS) was studied with the objective to halve the remaining heating demand of the three buildings. This report presents a synthesis of the main results obtained during the course of the Heumatt CSHPSS's system analysis and study. The main objective of the study is discussed: The aim was to develop a dynamic model the whole system and simulate its thermal performance to optimally dimension the system's main components. The system design and control strategy is explained. Further chapters contain the CSHPSS design results and thermal performance of different variants for a solar fraction of 50%. Rules of thumb are presented that are based on two variants. Finally, the results of optimisation measures taken on the largest variant (all three buildings) are presented and discussed. Sensitivities to some of the parameters are also examined.

  20. Discovery of Rapid and Reversible Water Insertion in Rare Earth Sulfates: A New Process for Thermochemical Heat Storage.

    Science.gov (United States)

    Hatada, Naoyuki; Shizume, Kunihiko; Uda, Tetsuya

    2017-07-01

    Thermal energy storage based on chemical reactions is a prospective technology for the reduction of fossil-fuel consumption by storing and using waste heat. For widespread application, a critical challenge is to identify appropriate reversible reactions that occur below 250 °C, where abundant low-grade waste heat and solar energy might be available. Here, it is shown that lanthanum sulfate monohydrate La2 (SO4 )3 ⋅H2 O undergoes rapid and reversible dehydration/hydration reactions in the temperature range from 50 to 250 °C upon heating/cooling with remarkably small thermal hysteresis (system for thermal energy storage. Thermogravimetry and X-ray diffraction analyses reveal that the reactions proceed through an unusual mechanism for sulfates: water is removed from, or inserted in La2 (SO4 )3 ⋅H2 O with progressive change in hydration number x without phase change. It is also revealed that only a specific structural modification of La2 (SO4 )3 exhibits this reversible dehydration/hydration behavior. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Energy storage and grid for electricity, gas, fuel and heat. A system-wide approach

    Energy Technology Data Exchange (ETDEWEB)

    Benesch, Wolfgang A. [STEAG Energy Services GmbH, Essen (Germany); Kakaras, Emmanouil [Mitsubishi Hitachi Power Systems Europe GmbH, Duisburg (Germany)

    2016-07-01

    Renewable energies are asked for more and more worldwide. Even though they cannot generate electricity 8760 h/a year. This can be accomplished by flexible conventional power stations as well as storage systems. Especially the storage systems have to be developed technical wise and especially economic wise. An example of an integrated approach is the methanol production with a coal fired power plant. An overview showing the technical features as well as the strategic opportunities of such kind of approach is given.

  2. Performance investigation of the capric and lauric acid mixture as latent heat storage for a cooling system

    Energy Technology Data Exchange (ETDEWEB)

    Dimaano, M.N.R. [University of Santo Tomas, Manila (Philippines). Faculty of Engineering; Watanabe, Takayuki [Tokyo Institute of Technology (Japan). Research Laboratory for Nuclear Reactors

    2002-07-01

    The thermal performance of the capric acid and lauric acid mixture (C-L acid) in the respective composition of 65% and 35% by mole was investigated for its cooling capacity. Pentadecane was used for comparison. A vertical cylindrical storage capsule was employed for the study. The temperature distribution of the C-L acid during charging and discharging inside a vertical tube was experimentally determined in both radial and axial directions. A melting point of 18-19.5{sup o}C was observed. This value corroborates with the DSC-obtained values for the C-L acid. The calculated stored energy based on the radial temperature distribution during charge and discharge processes indicates that the C-L acid is a potential latent heat storage material. (author)

  3. Smart intermittency-friendly cogeneration: Techno-economic performance of innovative double storage concept for integrating compression heat pumps in distributed cogeneration

    DEFF Research Database (Denmark)

    Blarke, Morten

    2011-01-01

    recovered from flue gasses as the only low-temperature heat source, furthermore applying an intermediate cold storage allowing for non-concurrent operation of heat pump and cogeneration unit. The novel concept is subject to a detailed techno-economic comparative modelling and analysis, hich finds...

  4. Thermal energy storage and heat transfer support program. Task-5 heat pipe life test study. Facilities upgrading and maintenance

    Science.gov (United States)

    Ponnappan, R.

    1991-03-01

    This report describes the recommissioning, upgrading, and maintaining of thirty low and five high temperature heat pipe life test rigs. This is an ongoing research effort, originally put together by NASA LeRC, continued by the Air Force. The 92 cm long 1.27 cm dia. spacecraft-type heat pipes have completed nearly 74,000 hours of life tests. They exhibit varying Delta Ts across the length and symptoms of gas accumulation. Life test status and temperature profile for each pipe are presented. The sodium and potassium pipes have undergone relatively less hours of testing (34,000 hours) only. These five pipes are exhibiting normal status. All the life tests will continue till failure and there will be updates of this report.

  5. Long-term modelling of Carbon Capture and Storage, Nuclear Fusion, and large-scale District Heating

    DEFF Research Database (Denmark)

    Grohnheit, Poul Erik; Korsholm, Søren Bang; Lüthje, Mikael

    2011-01-01

    Among the technologies for mitigating greenhouse gasses, carbon capture and storage (CCS) and nuclear fusion are interesting in the long term. In several studies with time horizon 2050 CCS has been identified as an important technology, while nuclear fusion cannot become commercially available...... on nuclear fusion and the Pan European TIMES model, respectively. In the next decades CCS can be a driver for the development and expansion of large-scale district heating systems, which are currently widespread in Europe, Korea and China, and with large potentials in North America. If fusion will replace...... fossil fuel power plants with CCS in the second half of the century, the same infrastructure for heat distribution can be used which will support the penetration of both technologies. This paper will address the issue of infrastructure development and the use of CCS and fusion technologies using...

  6. Effect of Heat-Treatment Process on Properties of Rare Earth Mg-Based System Hydrogen Storage Alloys with AB3-Type

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The effect of heat-treatment process on the properties of Mm0.8Mg0.2(NiCoAlMn)3.5 hydrogen storage alloy was discussed. The electrochemical properties such as cycling stability, activation property, and the plateau voltage of the alloy which was heat-treated in various temperatures and times had different changes during the cycle process, the optimum heat-treatment conditions of this alloy were determined by this work.

  7. Effect of Heat Treatment Process on Mechanical Properties and Microstructure of a 9% Ni Steel for Large LNG Storage Tanks

    Science.gov (United States)

    Zhang, J. M.; Li, H.; Yang, F.; Chi, Q.; Ji, L. K.; Feng, Y. R.

    2013-12-01

    In this paper, two different heat treatment processes of a 9% Ni steel for large liquefied natural gas storage tanks were performed in an industrial heating furnace. The former was a special heat treatment process consisting of quenching and intercritical quenching and tempering (Q-IQ-T). The latter was a heat treatment process only consisting of quenching and tempering. Mechanical properties were measured by tensile testing and charpy impact testing, and the microstructure was analyzed by optical microscopy, transmission electron microscopy, and x-ray diffraction. The results showed that outstanding mechanical properties were obtained from the Q-IQ-T process in comparison with the Q-T process, and a cryogenic toughness with charpy impact energy value of 201 J was achieved at 77 K. Microstructure analysis revealed that samples of the Q-IQ-T process had about 9.8% of austenite in needle-like martensite, while samples of the Q-T process only had about 0.9% of austenite retained in tempered martensite.

  8. Facade element with integrated latent heat storage and sun shading; TWD-Fassadenelement mit integriertem Latentspeicher und Sonnenschutz

    Energy Technology Data Exchange (ETDEWEB)

    Schwarz, D.; Nussbaumer, T.

    2002-07-01

    This final report for the Swiss Federal Office of Energy (SFOE) presents the results of on-site measurements made on transparent insulating material (TIM) elements that have been used in a single-family home built to 'passive house' standards in Ebnat-Kappel in Switzerland as part of a pilot and demonstration project. The aims of the project and the various passive components of the panels are described. These are a paraffin-based storage layer that stores / releases latent heat of melting, a glass prism sheet that prevents summer sunshine entering the house and two further glass window panes with infrared reflecting layers. The functioning of the TIM system is looked at in detail. Data on the performance of the complete passive house system including typical energy-relevant temperature curves for ambient and room temperature, heat-recovery system and buried ducting for air pre-heating and cooling are also presented, as are curves for the energy consumption of the house's heat pump and domestic hot water preparation.

  9. 地下混凝土储热桩换热器周围温度场的模拟分析%Underground concrete heat storage pipes heat exchanger around the simulation and analysis of temperature fileds

    Institute of Scientific and Technical Information of China (English)

    段会军; 赵大军

    2014-01-01

    通过对地下混凝土储热桩的储热研究,选用单U型埋管换热器,建立地下混凝土储热桩埋管换热器周围温度场模拟分析所用的物理模型和数学模型。通过模拟仿真,研究了储热桩体温度受埋管半径、埋管流量等参数变化的影响,并总结出受这些因素影响后储热桩内换热器周围混凝土温度场的变化趋势,为以后的实验研究提供了参考依据。%Based on the research on the thermal storage of the underground concrete heat storage pile,and with the help of the single U-shaped heat exchanger,we establish the physical and mathematical models to make analysis of the temperature field around the underground concrete heat storage pipes heat exchanger. Then,through the simulation,we study the variation of heat storage pile body temperature with the pipe radi-us,buried pipe flow and other parameters,and sums up the trends of the concrete temperature field around the heat storage pile,which provide a reference for the future experimental research.

  10. Applications of thermal energy storage to process heat and waste heat recovery in the iron and steel industry

    Science.gov (United States)

    Katter, L. B.; Peterson, D. J.

    1978-01-01

    The system identified operates from the primary arc furnace evacuation system as a heat source. Energy from the fume stream is stored as sensible energy in a solid medium (packed bed). A steam-driven turbine is arranged to generate power for peak shaving. A parametric design approach is presented since the overall system design, at optimum payback is strongly dependent upon the nature of the electric pricing structure. The scope of the project was limited to consideration of available technology so that industry-wide application could be achieved by 1985. A search of the literature, coupled with interviews with representatives of major steel producers, served as the means whereby the techniques and technologies indicated for the specific site are extrapolated to the industry as a whole and to the 1985 time frame. The conclusion of the study is that by 1985, a national yearly savings of 1.9 million barrels of oil could be realized through recovery of waste heat from primary arc furnace fume gases on an industry-wide basis. Economic studies indicate that the proposed system has a plant payback time of approximately 5 years.

  11. The direct heat measurement of mechanical energy storage metal-organic frameworks.

    Science.gov (United States)

    Rodriguez, Julien; Beurroies, Isabelle; Loiseau, Thierry; Denoyel, Renaud; Llewellyn, Philip L

    2015-04-07

    In any process, the heat exchanged is an essential property required in its development. Whilst the work related to structural transitions of some flexible metal-organic frameworks (MOFs) has been quantified and linked with potential applications such as molecular springs or shock absorbers, the heat related to such transitions has never been directly measured. This has now been carried out with MIL-53(Al) using specifically devised calorimetry experiments. We project the importance of these heats in devices such as molecular springs or dampers.

  12. Numerical modeling of heat transfer in the fuel oil storage tank at thermal power plant

    Directory of Open Access Journals (Sweden)

    Kuznetsova Svetlana A.

    2015-01-01

    Full Text Available Presents results of mathematical modeling of convection of a viscous incompressible fluid in a rectangular cavity with conducting walls of finite thickness in the presence of a local source of heat in the bottom of the field in terms of convective heat exchange with the environment. A mathematical model is formulated in terms of dimensionless variables “stream function – vorticity vector speed – temperature” in the Cartesian coordinate system. As the results show the distributions of hydrodynamic parameters and temperatures using different boundary conditions on the local heat source.

  13. Computational Evaluation of Latent Heat Energy Storage Using a High Temperature Phase Change Material

    Science.gov (United States)

    2012-05-01

    to ERC, Inc for the support of 2nd Lt Reid. REFERENCES (1) Zalba, B., Marin, J., Cabeza , L., and Mehling, H., 2003, “Review on Thermal Energy...pp. 1127-1138. (3) Streicher, W., Schultz, J., Sole, C., Cabeza , L., Bony, J., Citherlet, S., and Heinz, A., 2008, “Advanced Storage Concepts for

  14. Numerical Investigation of the effect of adiabatic section location on thermal performance of a heat pipe network with the application in thermal energy storage systems

    Science.gov (United States)

    Mahdavi, Mahboobe; Tiari, Saeed; Qiu, Songgang

    2015-11-01

    Latent heat thermal energy storage systems benefits from high energy density and isothermal storing process. However, the low thermal conductivity of the phase change material leads to prolong the melting or solidification time. Using a passive device such as heat pipes is required to enhance the heat transfer and to improve the efficiency of the system. In the present work, the performance of a heat pipe network specifically designed for a thermal energy storage system is studied numerically. The network includes a primary heat pipe, which transfers heat received from solar receiver to the heat engine. The excess heat is simultaneously delivered to charge the phase change material via secondary heat pipes. The primary heat pipe composed of a disk shape evaporator, an adiabatic section and a disk shape condenser. The adiabatic section can be either located at the center or positioned outward to the surrounding of the container. Here, the effect of adiabatic section position on thermal performance of the system is investigated. It was concluded that displacing the adiabatic section outwards dramatically increases the average temperatures of the condensers and reduces the thermal resistance of heat pipes.

  15. The effect of delay between heat treatment and cold storage on alleviation of chilling injury in banana fruit.

    Science.gov (United States)

    Wang, Haibo; Zhang, Zhaoqi; Xu, Lanying; Huang, Xuemei; Pang, Xuequn

    2012-10-01

    To understand the mechanisms leading to the enhanced chilling resistance of banana by hot-water dipping (HWD, 52 °C for 3 min), we investigated the effect of a 0.5-24 h delay between HWD and cold storage on chilling resistance and the change related to the metabolism of reactive oxygen species (ROS). The HWD-treated fruit with a delay of less than 6 h exhibited markedly less chilling injury than the non-heated control fruit, while a delay more than 6 h resulted in significant loss in chilling resistance. Increased hydrogen peroxide content and rate of superoxide radical production were detected in the fruit at 0.5-1.5 h after HWD treatment, and the levels declined with a longer delay, which may be correlated with the enhanced gene expression levels of the gene coding for a ROS-generating related enzyme, NADPH oxidase (MaNOX). Enhanced activities and gene expression of an ascorbate peroxidase (MaAPX) were recorded in the fruit at 1.5-6 h after the treatment, and after 6 h the ascorbate peroxidase levels decayed to the levels as the control fruit. The higher APX gene expression was maintained in the treated fruit with a 3 h delay during the subsequent cold storage at 7 °C, correlating with the enhanced chilling resistance. The HWD-treated fruit left at ambient temperature up to 6 h prior to cold storage maintained the effect of heat treatment and transiently increased ROS content, and the ascorbate peroxidase activity that occurred 0.5-6 h after the treatment may be correlated with the elevated chilling resistance induced by HWD treatment. Copyright © 2012 Society of Chemical Industry.

  16. Subsurface Thermal Energy Storage for Improved Heating and Air Conditioning Efficiency

    Science.gov (United States)

    2016-11-21

    buildings, schools, multi-family apartments, restaurants , retail buildings, motels, hospitals , etc.). Each of these building templates is populated with...imbalance arises from waste heat caused by lighting and other appliances, industrial machinery, communications and computing equipment, and people. Medium...and the air temperature is 70 oF, the heat rejection by the cooler is 404 kBTU/hr or about 34 tons (in the cooling industry , a ton is a unit of

  17. Analysis of coordination between the pohotovoltaic power generation and heat storage type air conditioning; Taiyoko hatsuden to chikunetsugata kucho no kyocho ni kansuru bunseki

    Energy Technology Data Exchange (ETDEWEB)

    Kita, H.; Sudo, T. [Kyoto University, Kyoto (Japan)

    1997-01-30

    This paper describes the effects of coordination between the photovoltaic power generation and heat storage type air conditioning. In this study, a linear programming model was analyzed in four cases of spread rates of photovoltaic power generation and heat storage tanks by selecting four setting angles of photovoltaic cell panels and six models of irregular variation, to determine the optimum demand and supply. As a result of the simulation, coordination effects were found independent of the cases. It was verified that the coordination effects can be obtained independent of the cases. For the capacity of heat storage tank, the influence of irregular variation of photovoltaic power generation was equivalent to about 10% of the capacity. The difference in the power generation costs between in the daytime and at night, and the construction costs of heat storage tank and air conditioner were considered as factors determining the capacity of heat storage tank. For the setting angle of photovoltaic cell panels, it was found that the intermediate setting was effective between the setting focusing on the peak power and the setting maximizing the annual power output. 4 refs., 7 figs., 3 tabs.

  18. Analysis of coordination between the pohotovoltaic power generation and heat storage type air conditioning; Taiyoko hatsuden to chikunetsugata kucho no kyocho ni kansuru bunseki

    Energy Technology Data Exchange (ETDEWEB)

    Kita, H.; Sudo, T. [Kyoto University, Kyoto (Japan)

    1997-01-30

    This paper describes the effects of coordination between the photovoltaic power generation and heat storage type air conditioning. In this study, a linear programming model was analyzed in four cases of spread rates of photovoltaic power generation and heat storage tanks by selecting four setting angles of photovoltaic cell panels and six models of irregular variation, to determine the optimum demand and supply. As a result of the simulation, coordination effects were found independent of the cases. It was verified that the coordination effects can be obtained independent of the cases. For the capacity of heat storage tank, the influence of irregular variation of photovoltaic power generation was equivalent to about 10% of the capacity. The difference in the power generation costs between in the daytime and at night, and the construction costs of heat storage tank and air conditioner were considered as factors determining the capacity of heat storage tank. For the setting angle of photovoltaic cell panels, it was found that the intermediate setting was effective between the setting focusing on the peak power and the setting maximizing the annual power output. 4 refs., 7 figs., 3 tabs.

  19. Cold and heat storage in downtown Berlin; Kaelte und Waermespeicherung im Zentrum Berlins

    Energy Technology Data Exchange (ETDEWEB)

    Seibt, P.; Brandt, W.; Kabus, F.; Moellmann, G.; Poppei, J. [Geothermie Neubrandenburg GmbH (Germany)

    1997-12-01

    The concept of energy supply for the seat of the German Parliament is based on self-sufficiency by using motor-driven district heating power stations. Esterified vegetable oil (bio-diesel) serves as fuel. These motor-driven power stations are operated depending on the amount of power required actually. The heat energy which is released when generating power at the temperature level >100 C - which is favourable for heating purposes - serves directly for heat supply or the driving a refrigerating machine/heat pump for the supply of cooling energy in summer and low-temperature heat in winter. As the demand on heat and power supply often will not be parallel, there will be a temporary surplus of heat offered by the motor-driven power station, and at other times it will be deficient. That is why surplus heat from the motor-driven power station is stored in a deep aquifer heat reservoir for recovery and utilisation for heating in winter. By using a geothermal saline water reservoir, the waste heat from the motor-driven power station can be fed into it at a temperature level ranging from 60.. 80 C and recovered and utilised at a temperature level ranging from 60.. 20 C. A shallow groundwater aquifer cold storing reservoir serves for cooling: the cold stored in winter is supplied in summer to the cooling equipment of the building by direct cooling with the cold water form the aquifer (heat exchange) at a temperature level of 14/15 C. The cooling demand in case of air dehumidification at a temperature level of 6/12 C is covered by a cooling machine which is also cooled with the cold water from the aquifer. As cooling machine/heat pump an environment-friendly, CFC-free absorption machine is used working on a combination of water and lithium bromide. The machine is driven by the waste heat from the motor-driven power plant. (orig.) [Deutsch] Im Zentrum des Systems der Energieversorgung der Parlamentsbauten steht die autarke Energiebereitstellung durch den Einsatz von

  20. Feasibility Study of a Building-Integrated PV Manager to Power a Last-Mile Electric Vehicle Sharing System

    Directory of Open Access Journals (Sweden)

    Manuel Fuentes

    2017-01-01

    Full Text Available Transportation is one of the largest single sources of air pollution in urban areas. This paper analyzes a model of solar-powered vehicle sharing system using building-integrated photovoltaics (BIPV, resulting in a zero-emission and zero-energy mobility system for last-mile employee transportation. As a case study, an electric bicycle sharing system between a public transportation hub and a work center is modeled mathematically and optimized in order to minimize the number of pickup trips to satisfy the demand, while minimizing the total energy consumption of the system. The whole mobility system is fully powered with BIPV-generated energy. Results show a positive energy balance in e-bike batteries and pickup vehicle batteries in the worst day of the year regarding solar radiation. Even in this worst-case scenario, we achieve reuse rates of 3.8 people per bike, using actual data. The proposed system manages PV energy using only the batteries from the electric vehicles, without requiring supportive energy storage devices. Energy requirements and PV generation have been analyzed in detail to ensure the feasibility of this approach.

  1. High efficient heat pump system using storage tanks to increase COP by means of the ISEC concept - Part 1: Model validation

    DEFF Research Database (Denmark)

    Rothuizen, Erasmus; Elmegaard, Brian; Markussen, Wiebke B.

    2015-01-01

    The purpose of the ISEC concept is to provide a high-efficient heat pump system for hot water production.The ISEC concept uses two storage tanks for the water, one discharged and one charged. Hot water for theindustrial process is tapped from the charged tank, while the other tank is charging....... Charging is done bycirculating the water in the tank through the condenser of a heat pump several times and thereby graduallyheating the water. The charging is done with a higher mass flow rate than the discharging to reach severalcirculations of the water during the time frame of one discharging....... This result in a lower condensingtemperature than if the water was heated in one step. Two test setups were built, one to test the performanceof the heat pump gradually heating the water and one to investigate the stratification in the storage tanks.Furthermore, a dynamic model of the system was implemented...

  2. Energy Payback Time Calculation for a Building Integrated Semitransparent Thermal (BISPVT System with Air Duct

    Directory of Open Access Journals (Sweden)

    Kanchan Mudgil

    2013-07-01

    Full Text Available This paper evaluates the energy payback time (EPBT of building integrated photovoltaic thermal (BISPVT system for Srinagar, India. Three different photovoltaic (PV modules namely mono crystalline silicon (m-Si, poly crystalline silicon (p-Si, and amorphous silicon (a-Si have been considered for calculation of EPBT. It is found that, the EPBT is lowest in m-Si. Hence, integration of m-Si PV modules on the roof of a room is economical.

  3. See-Through Dye-Sensitized Solar Cells: Photonic Reflectors for Tandem and Building Integrated Photovoltaics

    KAUST Repository

    Heiniger, Leo-Philipp

    2013-08-21

    See-through dye-sensitized solar cells with 1D photonic crystal Bragg reflector photoanodes show an increase in peak external quantum efficiency of 47% while still maintaining high fill factors, resulting in an almost 40% increase in power conversion efficiency. These photoanodes are ideally suited for tandem and building integrated photovoltaics. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Second test campaign of a pilot scale latent heat thermal energy storage - Durability and operational strategies

    Science.gov (United States)

    Garcia, Pierre; Rougé, Sylvie; Nivelon, Pierre

    2016-05-01

    A Phase Change Material (PCM) thermal energy storage module was tested in the framework of the Alsolen Sup project. Test results prove not only that the equivalent thermal resistance deduced from the first test campaign does not vary after several months and tens of melting and solidification cycles, but also that our modelling approach is valid both for design and non-nominal power rates, even if the model has to be improved to take into account varying water level and temperature stratification.

  5. Effect of heat processing and storage time on migration of bisphenol A (BPA) and bisphenol A-diglycidyl ether (BADGE) to aqueous food simulant from Mexican can coatings.

    Science.gov (United States)

    Munguia-Lopez, E M; Soto-Valdez, H

    2001-08-01

    Effects of heat processing and storage time (up to 70 days) on migration of bisphenol A (BPA) and bisphenol A-diglycidyl ether (BADGE) from can coatings into an aqueous food simulant were determined. Distilled water was canned in two types of Mexican cans: for tuna and for jalapeño peppers. Results showed that there is an effect of heat treatment on migration of both compounds. Storage time did not show any effect in BPA migration from tuna cans. There was an effect of storage time on BPA migration from jalapeño pepper cans. Results for BADGE migration were affected by its susceptibility to hydrolyze in aqueous simulants. BADGE concentration decreased, or was not detected, during storage in both types of cans. Migration levels for BPA and BADGE were within 0.6-83.4 and Mercosur legislation limits. Other migrating compounds were detected, although no identification was performed.

  6. The electrohydraulic balance of the solar heat storage with autonomous power supply

    Directory of Open Access Journals (Sweden)

    M. K. Marahtanov

    2014-01-01

    Full Text Available The introduction of the paper emphasizes an increasingly important role of alternative power sources nowadays. At the same time, a solar collector (suntrap is one of the most frequent techniques to use the solar energy. It is an absorber that picks up solar radiation and heats a heat carrier circulating in the close loop. Then the heat is transferred to the heat accumulator that is integrated in the hot-tap water system (HWS.The paper presents a prospective circuit of the solar collector. It differs from the traditional one because, in addition to absorbing panel, it uses photoconverters to generate electric power for the circulating pump. The advantage of this system is that for operation such a solar energy converter has no need in external power sources, i.e. it is autonomous. The need to calculate the essential thermo-physical parameters that ensure no-break system operation was stated as a main objective of the work.The suggested circuit has a photocell panel to convert solar radiation into dc voltage of 12 V. In case of a lack of the solar energy an accumulator battery can be used for feeding. To ensure the no-break supply of power an adaptor is offered.To calculate a density distribution of solar radiation a sine law is offered depending on the time of day and geographical locality. This dependence was used to obtain the expressions for calculating the water temperature in boiler over daytime.Further, the calculations have been done for the operating conditions under which an efficient heat exchange will be provided with the minimum consumption of electric power for the heat carrier circulation in the first loop. For this purpose, a pump power was calculated depending on consumption and hydraulic losses of head in the pipeline. As a minimum required consumption the value has been chosen at which a laminar flow regime changes to the turbulent one because of the most efficient heat exchange being both in collector and in heat accumulator

  7. Investigation of the Dynamic Melting Process in a Thermal Energy Storage Unit Using a Helical Coil Heat Exchanger

    Directory of Open Access Journals (Sweden)

    Xun Yang

    2017-08-01

    Full Text Available In this study, the dynamic melting process of the phase change material (PCM in a vertical cylindrical tube-in-tank thermal energy storage (TES unit was investigated through numerical simulations and experimental measurements. To ensure good heat exchange performance, a concentric helical coil was inserted into the TES unit to pipe the heat transfer fluid (HTF. A numerical model using the computational fluid dynamics (CFD approach was developed based on the enthalpy-porosity method to simulate the unsteady melting process including temperature and liquid fraction variations. Temperature measurements using evenly spaced thermocouples were conducted, and the temperature variation at three locations inside the TES unit was recorded. The effects of the HTF inlet parameters were investigated by parametric studies with different temperatures and flow rate values. Reasonably good agreement was achieved between the numerical prediction and the temperature measurement, which confirmed the numerical simulation accuracy. The numerical results showed the significance of buoyancy effect for the dynamic melting process. The system TES performance was very sensitive to the HTF inlet temperature. By contrast, no apparent influences can be found when changing the HTF flow rates. This study provides a comprehensive solution to investigate the heat exchange process of the TES system using PCM.

  8. Heat transfer analysis of consolidated dry storage system for CANDU spent fuel considering environmental conditions of Wolsong site

    Energy Technology Data Exchange (ETDEWEB)

    Lee, K. H.; Yoon, J. H.; Choi, B. I.; Lee, H. Y. [Korea Hydraulic and Nuclear Power Company, Taejon (Korea, Republic of)

    2004-07-01

    The purpose of the present paper is to perform heat transfer analysis of the MACSTOR/KN-400 dry storage system for CANDU spent fuel in order to predict maximum concrete temperatures and temperature gradients. This module has twice the capacity of the existing MACSTOR-200, which is in operation at Gentilly-2. In the thermal design of the MACSTOR/KN-400, Thermal Insulation Panels(TIP) were introduced to reduce concrete temperatures and temperature gradients in the module caused by the high fuel heat loads. Environmental factors such as solar heat, daily temperature variations and ambient temperatures in summer and winter at Wolsong site and the assumed presence of hot baskets were taken into consideration in the simulations. Two cases were performed for the MACSTOR/KN-400: Off-normal cases in summer and winter. The maximum local concrete temperatures were predicted to be 63 .deg. C for the off-normal case. The temperature gradients in the concrete walls and roof are predicted to be 28C and 25C for off-normal operation in summer, incorporating a 3C uncertainty. In conclusion, this paper shows that the maximum temperature for the module is expected to meet the temperature limitations of ACI 349.

  9. 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.

  10. Macro-encapsulation of heat storage phase-change materials for use in residential buildings. First quarterly progress report, September 29--December 29, 1976

    Energy Technology Data Exchange (ETDEWEB)

    Lane, G.A.; Kott, A.C.; Rossow, H.E.

    1977-02-01

    Objectives are to assess the feasibility of macro-encapsulated PCM's for residential solar systems, to develop and evaluate such materials. Five PCM's have been selected from encapsulation studies. Encapsulated storage media were evaluated theoretically in storage beds with air and water as the heat transfer medium. Cylindrical, tetrahedral, and pillow shapes are being evaluated for the encapsulated PCM. Encapsulant materials under consideration are multilayer flexible plastic films, steel cans, and plastic bottles.

  11. 太阳能在绿色建筑中的一体化应用%The Application of Solar Energy and Green Building Integration

    Institute of Scientific and Technical Information of China (English)

    李丹

    2013-01-01

    Solar energy and building integration is not a simple sum of the solar and construction, but the integration of building construction technology and the use of solar energy technology , the formation of a new modern green building. This paper describes passive solar architecture and active solar architecture features, including the direct benefit type, collector thermal storage wall and additional sun room. And briefly introduct the application of solar energy and building integration.%太阳能与建筑一体化不是简单的将太阳能与建筑相加,而是要通过建筑的建造技术与太阳能的利用技术的集成,整合出一个崭新的现代化绿色建筑。本文阐述了直接受益式、集热蓄热墙式、附加阳光间等被动式太阳能建筑和主动式太阳能建筑的特点,并简单介绍了太阳能和建筑一体化的应用。

  12. Body heat storage during intermittent work in hot–dry and warm–wet environments

    National Research Council Canada - National Science Library

    Stapleton, Jill M; Wright, Heather E; Hardcastle, Stephen G; Kenny, Glen P

    2012-01-01

    We examined heat balance using an American Conference of Governmental Industrial Hygienists threshold limit value allocated exercise protocol in hot–dry (HD; 46 °C, 10% relative humidity (RH)) and warm–wet (WW; 33 °C, 60% RH...

  13. Thermal analysis on organic phase change materials for heat storage applications

    Science.gov (United States)

    Lager, Daniel

    2016-07-01

    In this paper, methodologies based on thermal analysis to evaluate specific heat capacity, phase transition enthalpies, thermal cycling stability and thermal conductivity of organic phase change materials (PCMs) are discussed. Calibration routines for a disc type heat flow differential scanning calorimetry (hf-DSC) are compared and the applied heating rates are adapted due to the low thermal conductivity of the organic PCMs. An assessment of thermal conductivity measurements based on "Laser Flash Analysis" (LFA) and the "Transient Hot Bridge" method (THB) in solid and liquid state has been performed. It could be shown that a disc type hf-DSC is a useful method for measuring specific heat capacity, melting enthalpies and cycling stability of organic PCM if temperature and sensitivity calibration are adapted to the material and quantity to be measured. The LFA method shows repeatable and reproducible thermal diffusivity results in solid state and a high effort for sample preparation in comparison to THB in liquid state. Thermal conductivity results of the two applied methods show large deviations in liquid phase and have to be validated by further experiments.

  14. 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 and particu...

  15. 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 an

  16. Building Integrated Photovoltaics: A Concise Description of the Current State of the Art and Possible Research Pathways

    Directory of Open Access Journals (Sweden)

    Bjørn Petter Jelle

    2015-12-01

    Full Text Available Building integrated photovoltaics (BIPV offer an aesthetical, economical and technical solution to integrate solar cells harvesting solar radiation to produce electricity within the climate envelopes of buildings. Photovoltaic (PV cells may be mounted above or onto the existing or traditional roofing or wall systems. However, BIPV systems replace the outer building envelope skin, i.e., the climate screen, hence serving simultanously as both a climate screen and a power source generating electricity. Thus, BIPV may provide savings in materials and labor, in addition to reducing the electricity costs. Hence, for the BIPV products, in addition to specific requirements put on the solar cell technology, it is of major importance to have satisfactory or strict requirements of rain tightness and durability, where building physical issues like e.g., heat and moisture transport in the building envelope also have to be considered and accounted for. This work, from both a technological and scientific point of view, summarizes briefly the current state-of-the-art of BIPV, including both BIPV foil, tiles, modules and solar cell glazing products, and addresses possible research pathways for BIPV in the years to come.

  17. The operation of small cogeneration plants and short-term storage for district heating and public electric power

    DEFF Research Database (Denmark)

    Ilkjær, J; Petersen, P.M.; Qvale, Einar Bjørn

    1989-01-01

    A theoretical investigation of the economics of cogeneration supplemented by warm-water storage and subjected to a three-step price schedule for electricity, has been carried out. Some general guidelines can be derived, but no simple design rules, such as those for cogeneration plants operating...... with a two-step schedule, seem to govern the design of such plants subjected to the new conditions. Simulation studies have been initiated in order to arrive at sufficiently accurate optimal store dimensions and operational strategy. The results from simulation studies which give the store as a function...... of cogeneration plant size relative to the total heat demand in the geographical region supplied by the plant are shown...

  18. Effect of heat and moisture transport and storage properties of building stones on the hygrothermal performance of historical building envelopes

    Science.gov (United States)

    KoÅáková, Dana; Kočí, Václav; Žumár, Jaromír; Keppert, Martin; Holčapek, Ondřej; Vejmelková, Eva; Černý, Robert

    2016-12-01

    The heat and moisture transport and storage parameters of three different natural stones used on the Czech territory since medieval times are determined experimentally, together with the basic physical properties and mechanical parameters. The measured data are applied as input parameters in the computational modeling of hygrothermal performance of building envelopes made of the analyzed stones. Test reference year climatic data of three different locations within the Czech Republic are used as boundary conditions on the exterior side. Using the simulated hygric and thermal performance of particular stone walls, their applicability is assessed in a relation to the geographical and climatic conditions. The obtained results indicate that all three investigated stones are highly resistant to weather conditions, freeze/thaw cycles in particular.

  19. Transient natural convection and heat transfer during the storage of granular media

    Energy Technology Data Exchange (ETDEWEB)

    Avila-Acevedo, J.G.; Tsotsas, E. [Institute of Process Engineering, Otto-von-Guericke-University, P.O. Box 4120, 39106 Magdeburg (Germany)

    2008-07-01

    Transient heat transfer in an originally isothermal cylinder filled with a porous medium after sudden change of wall temperature is studied experimentally and computationally. Lab-scale experiments with water as the interstitial fluid are used in order to imitate the conditions prevailing in large, air-filled industrial silos. The proposed model assumes isotropy of the porous medium, local thermal equilibrium between the phases, Darcy flow and applicability of the Boussinesq approximation. Its predictions are in satisfactory agreement with the experimental results. Simulations reveal the role of dimensionless parameters like the modified porous media Rayleigh number and the cylinder aspect ratio. A criterion for neglecting the influence of natural convection on heat transfer is established. (author)

  20. Effect of nanoparticles on heat capacity of nanofluids based on molten salts as PCM for thermal energy storage.

    Science.gov (United States)

    Chieruzzi, Manila; Cerritelli, Gian F; Miliozzi, Adio; Kenny, José M

    2013-10-29

    In this study, different nanofluids with phase change behavior were developed by mixing a molten salt base fluid (selected as phase change material) with nanoparticles using the direct-synthesis method. The thermal properties of the nanofluids obtained were investigated. These nanofluids can be used in concentrating solar plants with a reduction of storage material if an improvement in the specific heat is achieved. The base salt mixture was a NaNO3-KNO3 (60:40 ratio) binary salt. The nanoparticles used were silica (SiO2), alumina (Al2O3), titania (TiO2), and a mix of silica-alumina (SiO2-Al2O3). Three weight fractions were evaluated: 0.5, 1.0, and 1.5 wt.%. Each nanofluid was prepared in water solution, sonicated, and evaporated. Measurements on thermophysical properties were performed by differential scanning calorimetry analysis and the dispersion of the nanoparticles was analyzed by scanning electron microscopy (SEM). The results obtained show that the addition of 1.0 wt.% of nanoparticles to the base salt increases the specific heat of 15% to 57% in the solid phase and of 1% to 22% in the liquid phase. In particular, this research shows that the addition of silica-alumina nanoparticles has a significant potential for enhancing the thermal storage characteristics of the NaNO3-KNO3 binary salt. These results deviated from the predictions of the theoretical model used. SEM suggests a greater interaction between these nanoparticles and the salt.