Investigation On Operation Characteristic Of Solar-Latent Heat Storage Water Tank System

Phase change material has characteristics of large energy density, strong storage capacity and its temperature during the phase transition is stablity, it can be absorbed a lot of heat during the phase transition (release) and very suitable for energy storage. Through made into a phase change unit and placed into the solar energy storage tank, the phase change material could increase the energy density, enhance the energy storage capacity of the solar heat storage tank and it also could provide more living water. Meanwhile the phase change material unit can be flexibly applied to the fields of waste heat recovery, new energy utilization and power adjustment and etc. In this paper, we use experiment and simulation as the primary research tool, from the design of phase change unit and solar energy-phase change energy storage tank to release the characteristics of cylindrical unit and solar-phase change thermal storage tank operation aspects related characteristics we did some research.Firstly, the article selected suitable phase change material for solar energy storage, through the experiment comparative study the heat storage and release of enhanced heat transfer characteristics under different manner as phase change thermal storage cylinder unit, at the same time the temperature distribution in cylinder phase change unit were studied and it is concluded that the expanded graphite is more obvious to improve the heat transfer performance for phase change materials than square metal and circular metal mesh. Through the experiment process we foud that during the melting process of phase change unit, melting process presents the rule from top to bottom, the law of the solidification process appears from the outside to inside, after further we verified the rule of phase transition and the law of the melt and solidification by numerical simulation in three different temperature conditions.Then, after we get the rule of the melt and solidification during phase transition in the cylinder unit.we took the solar energy resources in Xichang region for example, calculated the a three people family living water needs the area of solar collector surface is2.4m2, the volume of collector tank is180L. On this basis and the early research, we designed a solar energy-phase change thermal storage tanks.Finally, we calculated the fill rate of phase change materials in solar-phase change thermal storage tank, the results show that the heat storage tank put three cylinder filling phase change energy storage unit in Xichang area compared to ordinary solar storage tank can save hot water more than45.7L in the winter. Then we studied the running characteristics of phase change heat storage water tank through simulation and concluded that the temperature field distribution inside the water tank and the formation mechanism of phase change heat storage material properties, after added the phase change unit in the tank, the time of heat storage is285min, the time of heat release is42min. In the case of water for5min intervals, the time of water in phase change tank keep the temperature above40℃is89min; In the case of water for10min interval, the time of water in phase change tank keep the temperature above40℃is85min.