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Bansal, N. K. and D. Buddhi (1992). "Performance equations of a collector cum storage system using phase change materials." Solar energy 48: 185-194.
Abstract
A thermal analysis has been developed for a collector cum system for quasi-steady-state conditions using phase change materials. Performance equations of the Hottel-whillier-bliss type for flat-plate collector cum storage system have been obtained. Calculations have been performed for a wide range parameters to investigate the applicability of the developed mathematical model.
Costa, M., D. Buddhi, et al. (1997). "Numerical simulation of a latent heat thermal energy storage system with enhanced heat conduction." Energy Conversion Management 39(3/4): 319-330.
Abstract
A latent heat storage system has been designed to take advantage of the of-peak electrical energy for space heating. Using an enthalpy formation and a fully implicit finite difference method, the thermal performance of such a storage system with and without fins has been analysed. For the one-dimensional simulation model, calculations have been made for the melt fraction and energy stored for conduction plus convection and the conduction modes of heat transfer, while for the two-dimensional model, the same calculations have been made for conduction only. The magnitude of the melt fraction with fins is found to be considerable, dominating the melt fraction when no fin is used.
Costa, M., A. Oliva, et al. (1997). "Three dimensional numerical study of melting inside an isothermal horizontal cylinder." Numerical Heat Transfer An International Journal of Computation and Methodology 32(5): 531-553.
Farid, M. M. and A. Kanzawa (1989). "Thermal performance of a heat storage module using PCMs with different melting temperatures: mathematical modelling." Journal of Solar Engineering 111: 152-157.
Abstract
In the present study, the performance of a heat storage unit consisting of number of cylindrical capsules filled with phase change materials, with air flowing across them for heat exchange has been analysed. 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 co-ordinances, taking into account the radial temperature distribution in both phases. Heat flux was then evaluated at the surface of the first row of 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 minimise 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. Air must flow in the direction of decreasing melting temperature during heat charge, while it must be reversed during heat discharge.
Ghoneim, A. A., S. A. Klein, et al. (1991). "Analysis of collector-storage building walls using phase-change materials." Solar Energy 47(3): 237-242.
Abstract
The use of thermal storage walls that serve both as solar collector and thermal storage is well known. The wall is usually composed of masonry or containers filled with water to provide sensible heat storage, i.e. storage resulting from the specific heat capacity of a material as it increases in temperature. An interesting alternative to the standard materials are phase-change materials )PCMs) which employ latent heat storage. Latent heat storage utilises the energy associated with a change of state of a material such as the transition from the solid-liquid, or liquid-to-gas. The solid-liquid phase change is preferred for many applications because of the much smaller volume change resulting in this transition for a given amount of energy storage. This paper summarises the results of a simulation study of the use of PCMs as a collector storage wall.
Hoogendoorn, C. J. and G. C. J. Bart (1992). "Performance and modelling of latent heat stores." Solar energy 48: 53-58.
Abstract
A study has been made on organic phase change materials (PCM) for thermal energy storage in solar systems. The latent heat effects of these effects of these materials are obtained from calorimetric differential thermal analyser (DTA) measurements. Over the whole range of 25-150oC, suitable organic materials are available with heat effects of 150-230 kJ kg-1 including sensible heat. The low value of the thermal conductivity of these materials can be greatly improved by embedding a metal matrix structure in them. A numerical simulation model for the transient heat transfer in a PCM heat storage vessel has been set up and included in TRNSYS. Experiments with a 400L vessel confirmed the data obtained with this simulation model.
Kang, Y. H., Kwak, H.Y, et al. (1997). Numerical heat transfer analysis of heat storage board with microcapsule using phase change material [online]. Available from: http://oxford.elsevier.com [accessed 25 Feb 2000]. Abstract
In Korea floor heating is popular in the heating of a residential building. In this paper the heat storage board with microcapsule using phase change material is sued in the floor heating. A special grid (multi block and collocate grid) is used for the numerical simulation, particularly to solve the problem which pipe (hot water pipe) and square block (mixed cement and microcapsule) are located in the same domain at the same time. A mathematical model based on full 3-d non steady Navier-Stokes equations and scalar conversation equations together with turbulence model was used to predict temperature distribution of the capsule and velocity in the hot water pipe.
In the considered board not only the size of microcapsule suing PCM is very small, but also the microcapsule is mixed uniformly with the cement to form heat storage board. The phase change is a complex process. Thus, it is assumed that the phase change process cause only change of thermal properties of phase change materials and it does not generate any moving boundary. Two kinds of thermal boundary condition were considered. That is, 1st is adiabatic for the all of outer surface of wall; 2nd is the one of surface is natural convection with atmosphere. The perspective of this approach seems to be very promising in the direction of employing scientific tools to rationalise the heat storage system and microcapsule using phase change material.
Kerslake, T. W. and D. A. Jacqmin (1998). Radiation heat transfer modelling improved for phase-change thermal energy storage systems [online]. Available from: http://www.lerc.nasa.gov/WWW/RT1997?6000/6920kerslake3.htm [accessed 6 Mar 2000
Rajagopal, D., Krishnajwamy, et al. (1978). A simulation study of phase change energy store. Proceedings of the Int. Solar Energy Society Congress, New Delhi, India.
Abstract
Heat transfer to a phase change material in a cylindrical annulus was studied experimentally. Heat is transferred through the outer wall of the annulus with a circulant fluid. Different flow rates and inlet temperatures were used in both cooling and heating. The temperature histories in the material during heating showed interaction of transient conduction and natural convection. Heat transfer rate during heating is convection-controlled with main resistance in the molten material. The experimental results are correlated using simple convection correlations. These results are useful in the design of phase change thermal storage system.
Yanadori, M. and T. Masuda (1989). "Heat transfer study on a heat storage container with a phase change material (Part2. heat transfer in the melting process in a cylindrical heat storage container)." Solar energy 42: 27-34.
Abstract
Calcium chloride hexahydrate as a latent heat storage material is placed in a vertical cylindrical heat storage container, and a vertical single pipe for heat transfer purpose is also inserted in the container. In this set up, the heat transfer pipe to the heat storage material is largely influenced by natural convection at the melting liquid layer section. Also, regarding heat transfer at this melting liquid layer section, a new experimental equation useful for thermal design of heat storage containers has been established.
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