| Solar water heater is a typical solar thermal utilization system, it won the favor of consumers quickly with it’s environmentally friendly, safe, energy saving, health and other advantages. From the initial closed sunning type, flat type to now all glass vacuum tube, glass metal vacuum tube, solar thermal technology leap in the development, greatly improving the solar energy utilization efficiency, enrich the kinds of solar water heater. In storage technology, at present on the market most of the solar water heater still use water as an energy storage medium, but the water used as storage can material storage can feature for sensible heat storage. So this kind of type solar water heater’s energy storage density is small. In recent years, the research on the combination of the phase change thermal storage technology and the solar thermal utilization technology, the development of new phase change thermal storage solar water heater has become a hot spot for scholars in various countries.For this purpose, the application of phase change thermal storage technology in domestic solar water heater is discussed in this paper. It is hoped that a phase change thermal storage device can be designed, which can keep the heat storage capacity and the heat transfer performance of the device. It can store and release heat in time. So it can help to the solar water heater in a fine weather can most store solar energy. Then sloarwater heater can more quick start in the weather of solar water heater,and it can capture solar energy more efficiently. This requires that the heat storage device of the phase change heat storage device keep the high regenerative efficiency and the short regenerative time. To achieve rapid and exothermic heat transfer fluid has better heating performance to exothermic process. The research work mainly take from the structural design and experimental analysis of the phase change thermal storage device. The Conclusion of the design and optimization of the phase change heat storage device for the domestic solar water system can provided reference for home industrial design. The contents of this paper are as follows:(1) Take a comparative analysis of several phase change energy storage solar water heating system is carried. The thermal physical parameters of three phase change materials of sodium acetate, sodium hydroxide, barium hydroxide, twelve water ammonium sulfate, eight ammonium sulfate were tested.A combination of heat pipe vacuum tube collector with phase change heat storage tank is put forward, which Can better meet the household phase change energy storage type of solar water heater requirements. And as a starting point for this design idea,the development of structural design and research of regenerative device is take.(2) Several structural design ideas of the phase change heat storage device for passive household solar water heating system are proposed according to the requirements of the hot water to the storage quantity, the water temperature and the volume of the water tank of the tank. According to the theory of heat transfer, design of heat accumulating water tank structure, parameter setting and heat transfer calculation is take, and it contains of an indirect type phase change heat storage water tank, cylindrical capsules packed bed latent heat storage water, a spherical capsules packed bed latent heat storage water tank.(3) The experimental platform of the indirect phase change heat storage device with the spiral heat transfer coil is built. The test experiment of the indirect phase change heat storage device with the helical heat transfer coil is carried out, according to the standard of living water use. Experimental results show that:the indirect phase change heat storage tank with water as the heat transfer fluid can meet the requirements of the regenerative tank for the storage speed, when the phase change unit is replaced by water as the heat storage material, the phase change unit takes up the space of the tank. That convective heat transfer of heat transfer fluid in the tank has been weakened seriously. The heat release rate of water tank filled phase change unit is smaller when compared with the water tank without the filling phase change unit.(4) The test platform of the phase change heat storage device of cylindrical capsules packed bed and spherical capsules packed bed latent heat storage water tank was established, and the heat storage tank of the cylinder packed bed was designed and the heat release performance was tested. The practicability of the structure is analyzed by comparing with the heat storage tank of the phase change unit. Experimental results show that:A twelve water aluminum sulfate ammonium sulfate as a phase change energy storage material for cylinder packed bed storage tank. Although it has a large heat exchange area, easy for heat. However, the heat transfer efficiency of the water tank is compared with the storage tank of the phase change unit, and the heat storage tank is only 0.6% of the heat efficiency. The phase change material of the high melting point is not suitable for the solar water system. For the spherical bulk bed with eight water hydroxide barium hydroxide, the phase change of the storage tank. When the phase change material quality fill rate were 13%,26%,42%, the water tank heat efficiency were 79.41%,84.99%,78.29%, respectively. Compared with the ordinary water tank heat release rate of 77%, the test result shows that the new type heat storage water tank is more efficiency than the normal one. The design of the phase change heat storage device of the ball bed is reasonable, and can basically meet the use requirements. |
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