Study On Key Technologies Of A Heat Pump Water Heater With Energy Storage System

With the development of economy and the improvement of people's living quality, the energy consumption of residents increases rapidly, among which, hot water for everyday life occupies a very great proportion. At present, hot water for domestic purposes is usually generated by a water heater that consumes high grade sources of energy such as natural gas and electricity. Therefore, the study of energy conservation of the domestic water heater will directly facilitate the proper utilization and development of energy for domestic uses, which is of great significance to energy conservation and environment protection of the whole society. To this end, the thesis focuses on the performance of a heat pump water heater with a phase-changing latent heat storage apparatus both in theories and experiments.In this thesis, an experimental setup for heat pump water heater using paraffin wax as the phase-changing heat storage material is improved and the systematic testing and analysis of the performances of the heat pump system under different working conditions are conducted. A large quantity of experimental data has been obtained, which provides the foundation data for further improvement research of this heat pump system.In the course of its running, it has been shown that the condensing device (the thermal storage device and the heating heat exchanger) of this heat pump system not only coexist heat charging and discharging with phase changing process but also integrating multiple heat transfer types in one container, which results in a very complex heat transfer process of it. There is no related research literatures have been found on this topic.On the basis of the investigation of heat transfer mechanisms, this thesis set up a mathematical model for such a condensing equipment and solved it numerically. Comparing experimental results with theoretical ones, it is demonstrated that the proposed model can be used to describe the running characteristic of such an equipament.Heat transfer enhancement in phase change material is the key technology that can improve performance of the heat pump water heater. Therefore, a series of studies is carried out focusing on heat transfer characteristic enhancement in phase change material and put forward a method of using additives for this purpose. Heat conductivity in solid and liquid states of different compositions of paraffin and gasified SiO₂ and different compositions of paraffin and organic...