The Development Of The Phase Change Heat Storage-evaporator Air-source Heat Pump Control System

This paper is one of the important sub-topics of the major science and technology projects "monitoring of major production equipment for coal mine and life cycle management system development based on Internet of things（No:20131101029）". Its mainly aimed at the poor performance of air source heat pump heating in low temperature environment, such problems as low efficiency and frequent failure. Fossil fuel consumption occupies the 90% of the total energy consumption in our country, appearing the serious environmental pollution problems at the same time, for example the haze weather severely affects the health of modern people, Although the government has published a series of measures for energy conservation and emissions reduction, with little success, If energy use structure does not change, environmental pollution will continue to exist for a long time, certainly will influence the development of the country and people’s quality of life. The air source heat pump as a clean energy, and its absorption heat from air converted to other forms of energy, clean and no pollution, is one of the direction of the future of new energy development. Developed countries especially Japan in both research and application level of air source heat pump is in a world leading position, while Europe also widely to encourage people to use air source heat pump, therefore, the research and application of air source heat pump is becoming urgent.Air source heat pump is used widely in the south of China, it`s convenient, energy efficient and less pollution. Because of low ambient temperature in the north of China, air source heat pump have a series of problems in the application process. At present most areas in north China still depends on coal based way of central heating, central heating have serious environmental pollution and can not according to user needs to adjust and other shortcomings. In order to solve the application of air source heat pump in low-temperature environment problem and increase heat pump heating performance under the harsh conditions to promote the application of air source heat pump in the north, After many years of research, our research team develope a phase change heat storage-evaporation air source heat pump system. Compared with the conventional air source heat pump system, this system attach to a phase change thermal storage device, heat storage material with 80%Na₂SO₄?10H₂O+20%Na₂HPO₄?12H₂O. When the outdoor temperature higher than the heat pump system design equilibrium point-5℃, the system run on heating-heat storage mode, the extra heat energy is stored in the regenerator using the phase change heat storage technology; When the outdoor environment temperature below-5℃, system run on heating – heat releasing mode, regenerator as auxiliary evaporator of heat to the system and for the user, and transfer heat in the timeline. solve the air source heat pump heat supply and demand contradiction in low temperature environment, at the same time enhancing the safety and economic behavior of air source heat pump at low temperature operation; When ambient temperature is very low, the system will appear frost phenomenon, system run on defrosting-heating mode, and defrosting by using the heat in the regenerator, The whole process realizes the rapid and efficient energy-saving defrosting using phase change heat storage, shortens the time of defrosting and significantly improves the heating quality and operation performance of air source heat pump.In this paper, based on the above phase change heat storage type air source heat pump evaporation system, We develop the evaporation phase change heat storage type air source heat pump system prototype, and develop its microcontroller control system based on STM32F103, design the data acquisition and output control circuit and system software, main equipment import and export of heat pump units line parameters such as temperature, water level height and compressor pressure can be real-time acquisitied and display. System combined with the temperature hysteresis and degree of superheat PID algorithm to control heat pump compressor, water pump, four-way reversing valve, evaporator, pipe line electromagnetic valve and electronic expansion valve and other components, realizes the air source heat pump hot water unit of safe, reliable and economic operation. Through laboratory debugging and field using test, phase change heat storage-evaporator air-source heat pump in three kinds of mode is with excellent performance. Experimental results show that phase change heat storage-evaporator air-source heat pump solves the air source heat pump in heating process of the contradiction between supply and demand of energy, at the same time improves the performance of air source heat pump under low temperature environment, the system performance is stable, reliable, energy saving, The system COP is 2.1 in-5℃,provids a new train of thought for application of air source heat pump in the northern region.