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Bourdeau, L. and A. Jaffrin (1979). Actual Performance Of A Latent Heat Diode Wall. Proc. Int. Symp. II On Solar Energy Fundamentals & Applications, Izimir, Turkey.
Abstract
A prototype solar heating system has been tested during March 1979 in Nice. This system is used to heat a small experimental house with no auxiliary. It consists of an air collector and a storage wall separated by an insulation. The storage wall is made of concrete blocks filled with latent heat material. Heat transfer from the collector to the storage is provided by forced air during the day. The head restitution at night is completely passive. Heat losses occurring through the front side of the wall are smaller than in a Trombe system. The results obtained in a cool month of March 1979 show that this diode wall is able to keep the ambient temperature of the test house 10 to 15 ēC higher than the outside temperature at night under most circumstances. Detailed analysis suggests possible improvements of this diode wall and gives confidence in a future industrialisation of the system
Buddhi, D. Thermal performance of a shell and tube PCM storage heat exchanger for industrial waste heat recovery [online]. Solar Energy On line. Available from: http://oxford.elsevier.com [accessed 25 Feb 2000] Abstract
A significant amount of heat is wasted in electricity generation, manufacturing, chemical and industrial process. Recovery and reuse of this energy through storage can be useful in conservation of energy and meeting the peak demands of power. A shell and tube type heat exchanger has been designed and fabricated for low temperature industrial waste heat recovery using PCM; Stearic acid has been used as a storage media. Stearic acid is selected due to its low cost and large scale availability in Indian market.
Experiments have been performed for different mass flow rates and inlet temperature of heat transfer fluid for recovery and use of waste heat. The performance shows the feasibility of using PCM should as storage media and also shows that the shell and tube radius, mass flow rate and radial distance between heat transfer tubes to compensate the poor thermal conductivity of the PCM should be chosen carefully in order to optimise the performance of the heat exchanger
Edie, D. D., S. S. Melsheimer, et al. (1979). Latent heat energy storage using direct contact heat transfer. Sun 2 Proc. Of The Int. Solar Energy Soc. Silver Jubilee Conf.
Abstract
The use of direct contact heat transfer in latent heat energy storage systems has been proposed as a means of combating phase segregation problems and enhancing heat and mass transfer performance in such systems. Recent studies at Clemson University have shown that several salt hydrates perform satisfactorily, and that acceptable heat transfer fluids are available. Studies of system geometry and heat transfer performance, as well as crystal growth velocity, have also been completed. data are now being collected on a 200l prototype unit, which will provide long term performance information under realistic operating conditions.
Egolf, P. W., M. Koschenz, et al. (1995). Storage devices containing phase change materials for low energy buildings [online]. Available from: http://oxford.elsevier.com [accessed 25 Feb 2000]
Abstract
The behaviour of low energy buildings with solar energy systems containing phase change material (PCM) storages shall become precisely predictable. This especially requires the study of seasonal thermal storage in medium-sized, respectively large PCM containers. Therefore simple models e.g. low biot number models, cannot lead to accurate results. Noteworthy is the performance of the continuous-properties model (CPM), which is discussed in this article. Numerical results are compared with experimental data obtained with two different experimental devices.
Ei-Sayed, M., H. M. Henning, et al. (1996). Experimental and theoretical study of a new phase change material [online]. Eurosun 96, International Solar Energy Society Conference. Available from: http://www.oses.org/ [accessed 23 Mar 2000)
Frysinger, G. R., J. Sliwkowski, et al. (1979). Commercialisation Of Storage Assisted Air Conditioning Using Phase Change Materials. ASHRAE TRANS: 516-523.
Abstract
Storage assisted air conditioning offers one of the most significant opportunities on the customer side of the meter for load management by summer peaking utilities. The commercialisation of this storage system is based on the successful development of a new low cost component containing thermal energy storage materials. Full-scale system tests of the storage assisted air conditioning have been operating in Solar One, the University of Delaware's test house, in two different configurations during 1978. Extensive field tests are planned for the summer of 1979.
Goswami, D. Y., C. K. Jotshi, et al. (1995). Thermal storage in ammonium alum/ammonium nitrate eutectic for solar space heating. Proceedings of Solar 5 The 1995 AM Solar Energy Annual Conference.: 336-341.
Abstract
Ammonium alum and ammonium nitrate in the weight ratio of 1:1 forms a Eutectic that melts at 53oC and crystallises at 48oC. The latent heat of fusion of this eutectic was found to be 2185kj/kg. Its enthalpy as measured by drop calorimetry was found to be 287kj/kg in the temperature range of 25-67oC, which is 1.67 times greater than water (172.2kj.kg) and 8.75 times greater than rock (32.8kj/kg). Upon several heating/cooling cycles, phase separation was observed. However, by adding 5% attapulgite clay to this eutectic mixture, phase separation was prevented. This eutectic was encapsulated in 00.0254m diameter HDPE hollow balls and subjected to about 1100 heating/cooling cycles in the temperature range between 25 and 65oC. At the end of these cycles, the decrease in enthalpy was found to be 5%. A scale model of the heat storage unit was fabricated to investigate the heat transfer characteristics of this eutectic encapsulated in HDPE balls. The thermal extraction efficiency of the system was measured with the re-circulation of hot air during charging and was found to be in the range of 85-89%.
Hasan, A. (1994). "Phase change material energy storage system employing palmitic acid." Solar Energy 52(2): 143-154.
Abstract
Experimental investigation of palmitic acid as a phase change material (pcm) for energy storage has been carried out in this work. The parametric study of phase transition included transition times and temperature ranges, propagation of the solid liquid interface, as well as the heat flow rate characteristics of the employed circular tube storage system. The experimental results proved that the melting front moves in the radial as well as in the axial directions. The convection heat transfer in the liquid phase plays an important role in the melting process. And the simple conduction model does not describe the melting process properly. The flow rate, of the heat transfer fluid in the experimental range, has insignificant effect on the transition process. The melting time can be reduced significantly by placing the tube containing the PCM in a horizontal position rather than in a vertical one. The dimensionless phase transition time is related to stefan number by a simple correlation.
Greenhouse heating [online]. Solar Energy Online. Available from: http://oxford.elsevier.com [accessed 25 Feb 2000]
Abstract
It is desirable to use the renewable energy for the greenhouse heating in winter season, it makes it possible not only to save fossil fuel and conserve green farm environment but also to promote the quality of agricultural products and reduce the agricultural production cost. In this study the heat pump - PCM latent heat storage system has been developed o use natural energy as much as possible for the thermal environment control of greenhouse. The coefficient of performance (COP) of the heat pump system was 3-4 with the ambient temperature ranging from 8ēC to -8ēC and greenhouse heating effect of the heat pump - PCM latent heat storage system on the basis of the ambient temperature was about 13-15ēC
Kauranen, P., K. Peippo, et al. (1991). "An organic PCM storage system with adjustable melting temperature." Solar Energy 46(5): 275-278.
Abstract
A proper storage temperature is an important criterion for selecting a phase change material (PCM) for a passive solar heating application. Here we describe a novel procedure to produce a mixture of carboxylic acids with a melting temperature adjustable to the climate specific requirements. The approach is based on the ideal solution model and differential scanning calorimetry (DSC). The applicability of the method is demonstrated and it is also applied to a PCM wall design. The accuracy of the theoretical model is +- 2° C in the temperature range of 20ēC -30ēC and even = -0ēC accuracy can be obtained by the experimental procedure.
Lane, G. (1980). "Low temperature heat storage with phase change materials." The international journal of ambient energy 1(3): 155-168.
Abstract
A group of promising phase change heat-storage materials was selected through study of the literature, laboratory tests of freeze-melt behaviour and determination of thermophysical properties. Means were developed of encapsulating these materials in metal or plastic containers. Four of these phase change materials, suitably encapsulated, were tested in a sub-scale thermal storage unit of about 20MJ capacity, using air as the heat-transfer fluid. In most cases, measured thermal storage capacity exceeded 90% of the theoretical value. After considering a number of heating and cooling schemes employing phase-change heat storage, we selected a forced hot air, central storage design, using CaCl2 6H2O encapsulated in plastic pipes. A home was designed, using a two-storey conservatory for solar collection with vertical glazing and movable insulation
Lane, G. (1980). "Low temperature heat storage with phase change materials." The international journal of ambient energy 1(3): 155-168.
Abstract
A group of promising phase change heat-storage materials was selected through study of the literature, laboratory tests of freeze-melt behaviour and determination of thermophysical properties. Means were developed of encapsulating these materials in metal or plastic containers. Four of these phase change materials, suitably encapsulated, were tested in a sub-scale thermal storage unit of about 20MJ capacity, using air as the heat-transfer fluid. In most cases, measured thermal storage capacity exceeded 90% of the theoretical value. After considering a number of heating and cooling schemes employing phase-change heat storage, we selected a forced hot air, central storage design, using CaCl2 6H2O encapsulated in plastic pipes. A home was designed, using a two-storey conservatory for solar collection with vertical glazing and movable insulation
Merry, N. (1989). Energy storage in a fluidised bed. Transactions of the ASME journal of heat storage transfer. 111: 726-730.
Abstract
An experimental study was performed to investigate the possible use of a compound that undergoes solid-solid phase transformation for energy storage in a fluidised bed configuration, and to determine the heat transfer characteristics of this system . It was shown that the heat transfer coefficients from a surface immersed in the fluidised bed are a function of the bed temperature and of the temperature of the immersed surface. The heat transfer process is enhanced by the phase transformation by as much as a factor of four relative to the heat transfer in the same material without phase transformation. The experimental results suggest the possible existence of a thermal resistance between the surface immersed in the fluidised bed and the particles, which is responsible for the particular experimentally observed thermal behaviour.
Salyer, I. O. and A. K. Sircar (1993). Development of phase change technology for heating and cooling of residential buildings and other applications. Proceedings of the 28th intersociety energy conversion eng conference.: 2.133-2.143.
Abstract
The research reported herein is a continuation of work sponsored by the department of energy's solar passive division (1982-7988) and the office of energy storage and distribution at oak ridge national laboratory (ORNL) (1988-1993). The program objectives were 1. To define a cost effective, environmentally safe, solid-liquid, phase material (PCM) that would melt and freeze sharply and concurrently at about 25ēC, and have a heat of fusion +30 cal/g and 2. develop methods by which the PCM could be incorporated into building materials (specifically plasterboard) to accomplish energy conservation and electric peak-load shifting in residential and commercial buildings.
These DOE PCM-plasterboard research goals have been achieved. A suitable low-cost linear alkyl hydrocarbon PCM from petroleum refining has been defined, and methods of containing the PCM to eliminate leakage and problems of expansion in melting in melting and freezing have been developed. Processes whereby this PCM could be incorporated into plasterboard either by post manufacturing imbibing of liquid PCM into the pore space of the plasterboard or by an additive that could be incorporated into the wet stage of plasterboard manufacture have been developed and tested in detail. Both of these processes have been successfully demonstrated in the laboratories of the University of Drayton Research Institute, national Gypsum Company (NGC) and United States Gypsum Company (USG). Large scale plant production and testing of storage effectiveness and comfort factor in residential buildings remains to be performed. Of the six PCM containment methods investigated the most promising are:
1. imbibing the PCM into porous materials (egg plasterboard)
2. permeating the PCM into polymetric carriers (egg cross linked pellets of high density polyethylene)
3. Absorbing the PCM into finely divided special silicas to form soft free flowing dry powder. The PCM/silica dry powder appears to be of the strongest interest to the plasterboard manufacturers. Furthermore, it is the most recent and nearly universal method of containment for new and different applications.
During the research program, many new applications for PCM technology were studied. Several of these applications are in active development toward commercialisation. Additional exploratory applications of interest are still under laboratory study. details of theses developments are presented in the following sections.
Benard, C., D. Gobin, et al. (1978). Theoretical and experimental analysis of a latent heat storage system. Proceedings Of The International Solar Energy Society Congress, New Delhi, India.
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