Heat Transfer Enhancement Of Phase Change Thermal Storage And Experimental Research On Characteristics Of Phase Change Heat Exchanger

Heat storage technology is an important technology which can improves energy efficiency and protects environment. Latent heat thermal storage has many advantages,such as high storage density and small heat storage temperature variation,etc. It has become the focus in this field. However, the phase change thermal storage is mainly applied on the high temperature and low temperature range at home and abroad. The research and application of mid-temperature phase change thermal energy storage technology is less. Mid-temperature phase change thermal storage technology has a wide range of applications in the fields of solar energy use,waste heat and waste heat recovery utilization. Thermophysical properties of phase change materials and enhancing heat trransfer structure are tested in this thesis. Characyeristics of thermal storage are researched by experiment.It has has important practical significance.Phase change material and heat storage exchanger structure are two sides of storage technology research and development. Only when the two sides are combined closely, the development of heat storage equipment can meet demand of the actual application. In the thesis, erythritol is choosed as mid-temperature latent heat thermal energy storage materials. The thermal properties are measured according to the conductivity apparatus and DSC. The advantages of this material are verified,such as stable latent heat performance,high latent heat and no poison. So this material can be applied in mid-temperature field. The effective thermal conductivity with filling metal fins and copper foam is derived.Then a latent heat storage unit is proposed and designed which is integrated with of the copper foam and heat pipe. Heat transfer ability of erythritol is strengthened according to heat pipe. Then the experiment of heat storage and heat release is carried out. Heat storage time and heat power at different heating water flow are obtained. Good heat capacity and thermal insulation of the heat storage exchanger are confirmed by the experimental results.Mathematical model of the erythritol with filling copper foam in the heat storage exchanger is established by GAMBIT. Melting process of the materials in the heat storage exchanger is simulated by FLUENT. Temperature changes and the distribution situation of heat storage materials in the various time periods are obtained. The correctness and feasibility of the model are proved by comparison. It will offer reference to the simulation of the similar situation in future.