| Solar and air source heat pump integrated system with triple-sleeve energy storage exchangers is introduced in this paper. It is a new system which combines the solar collectors, air source heat pump and the cool storage units with triple-sleeve energy storage exchangers. The new system makes best use of the cleaning renewable energy, solar energy and air source energy, and makes them as complementarily for each other. At the same time, the new system will improve some problems of the conventional system such as large consuming energy, wasting energy and thermal pollution to environment. Therefore, SAHPIS is obviously in favor of development economy, environment and society. It promotes the new conceptions of ecologic cycle heating and rational energy utilization.Because of the unique design of SAHPIS, it can operate in different modes according to the climate conditions or the demands of consumers by a simple control strategy. The different modes are listed as follow: cold supply mode using air heat pump and domestic hot water supply in summer, cold storage mode in summer, cold release mode and domestic hot water supply in summer, cool supply and cool storage mode in summer, joint cool supply mode and domestic hot water supply in summer, heating mode in winter, heat storage mode in winter, heating mode using heat storage in winter, heating mode using air heat pump in winter, joint heating mode using air heat pump and heat storage in winter, joint heating mode using air heat pump and solar energy in winter. So, it is a multi-source heat pump system which can be used in the whole year. The system has many characteristics such as multi-function, strong applicability and better effectiveness.The proper phase change material is selected from existing commercial phase change materials based on the characteristics analysis of SAHPIS. Then, an experimental table of the key unit, triple-sleeve energy storage exchanger, is built. The pressure of inlet and outlet of compressor, the compressor ratio and the energy variation of the experimental refrigerant system is tested in the three typical modes. The experimental data validates the feasibility of SAHPIS.In order to study the operation characteristics of SAHPIS and the heat exchange characteristics of triple-sleeve energy storage exchanger, distributed parameter simulation models of triple-sleeve energy storage exchanger is built up. Enthalpy model is used to establish the mathematic model for heat transfer of PCM in the middle layer of triple-sleeve energy storage exchanger. The steady distributed parameter mode is established for tube in tube condenser. The compressor model is founded in map-based method, and the thermodynamics expansion value model is built up in force balance method. The dynamic system model is the efficient connection of all component models by laws of equalization of mass, momentum and energy. These models can provide powerful tools for studying operation performance of SAHPIS.The variation of parameters of experimental refrigerant system such as condensing temperature, evaporation temperature, condensing heat, the pressure of inlet and outlet of compressor, energy storage and COP are simulated in cold storage mode, heating mode using heat storage, heating mode both absorbing and releasing. Some factors that lead to drastic fluctuating of system parameters are analyzed by simulating. At the same time, the heat conduction during the phase change process and heat exchange characteristics of triple-sleeve energy storage exchanger is studied in cold storage mode, cold release mode, heat storage mode, heating mode using heat storage, heating mode both absorption and release. The feasibility, reliability and validity of models established in this paper are validated by comparing the test results and simulative results in process of thermal storage and using water in space cooling and water heating mode.Based on the mathematical simulation and the experiment research of triple-sleeve energy storage exchanger, the characteristics of triple-sleeve energy storage exchanger is analyzed and compared with experiment data. The correctness of the triple-sleeve energy storage exchanger mathematics model is confirmed. These will provide the theoretical foundation for optimizing operation and control of SAHPIS, also provide an instruction for making SAHPIS products in the future.
|
PDF Full Text Request