Numerical Simulation And Experimental Study On Enhancement Of Foam Metals To Phase Change Heat Storage

The rapid development of society demands larger amount of energy consumption, this has lead to the world's attention on reducing energy consumption as well as exploiting renewable energy. In order to promote the efficiency of clean renewable energy resources such as solar energy and to create much better environment for human being, Phase Change Thermal Energy Storage has been used broadly due to the merits of high-density energy storage and easily-controllable process. However, many phase change materials have a relatively low thermal conductivity, which is bound to seriously affect the heat transfer rate and thawing rate. Foam metal, with its light weight, high heatcapacity, high thermal conductivity and etc, will have broad application prospects in the field of phase change heat storage in the high thermal conductivity filler in the aerospace, aviation and environmental protection.In this article, paraffin wax is used as the phase change materials(Phase Change Materials, PCM), besides, it also investigates the influence of temperature gap and high conductance filling to efficiency in the paraffin's energy storage and release process through experimental analysis and numerical simulation. Firstly, based on the experimental physical model and advisable assumptions, a mathematic model is set up. Fluent is used to solve the problem and analyze the results of simulation. The results show that greater heat transfer temperature difference will result in higher heat efficiency. At the same time, additional metal foam not only increases the heat release rate, but also has the temperature of the heat storage containers more evenly distributed. Later, a thermal energy storage unit experimental device is designed and an experimental system is built up. We design many groups of experiment schemes to carry on the experiment, and Agilent 34970A was used to gather the data of the temperature and flow rate of HTF. The experiment is divided into charging and discharging processes, in which we have carried on repeated charging and discharging experiments in different import temperatures and with or without the foam materials. In addition, we have analyzed the effects of inlet fluid temperature and high conductance filling on the performance of the storage unit as well. The experimental result shows that a higher charging temperature or a lower discharging temperature would both shorten the phase change time and increase the efficiency. The foam material will not only lead to a more uniform distribution of the temperature of thermal energy storage unit, but also shorten time of the charging and discharging processes on a large extent. The results of experiment and simulation are compared and errors are discovered between them. We find that in the process of numerical simulation, a certain assumption is applied to the model for the purpose of simplifying it. In the process of experiment, inevitable heat loss and personality errors exist. All of these are reasons of those errors between numerical simulation results and experimental results. But the error is within the allowable range theoretically, so it can validate the applicability of academic model and offer the reference basis for design, optimization, and appreciation of the thermal energy storage unit.