| Building a resource-saving society is the most important thing to China and has respect to its economy and social sustainable development. Energy conservation is an important part of building a resource-saving society. In 2008, China’s building energy consumption is about 23% of total energy consumption. The heating energy consumption of the northern cities and towns accounts for about 22.7% of the total energy consumption of the building which builds the largest proportion of the total energy consumption. So the heating energy conservation is essential to building a resource-saving society.Air source heat pump has become the focus of the domestic and foreign scholars for its prominent energy saving effect, low operating costs, environmental protection, short payback period, long service life, heat source (air) which can get everywhere and many other advantages. But the traditional air source heat pump has low efficiency under low temperature conditions or even can’t run normally. So its development and application in the northern area of our country especially on the bitter cold and cold region is severely restricted.In allusion to the phenomenon that the performance of air source heat pump is poor on low temperature environment in north china, one air source heat pump system with a heat-storage evaporator was designed and its test-bed was built in order to extend its applicability. The performance of regenerator which is the key to solve the applicability problem on low temperature conditions for heat pump is the research direction of this subject.In this thesis, cylindrical double helix coil phase change regenerator was proposed firstly, its shape is cylindrical, heat exchanger structure is two concentric spiral coil with copper, filled with phase change thermal storage material. It’s characteristic which differ from other phase change regenerator is that one spiral coil is used to store heat and the other one is used to release heat. That is to say that regenerator that can not only act as the economizer to improve operating efficiency on heat storage condition, but also release heat as the evaporator to the system on low temperature condition, and also is able to provide heat for defrosting. All above it is a strong guarantee for the heating effect of the air source heat pump.The characteristics of heat charge and discharge at different outdoor temperature and the performance of defrosting were experimental researched. The results show that the heat-storage evaporator has good heat-storage and heat-release capacity, it can meet the heating demand in low temperature condition guaranteed by air source heat pump system, and solve the contradiction between heat supply and heat need effectively, and also shorten the defrosting time by 50%, this improve the heating effect. The results also show that the speed of heat storage is slow at the beginning and the amount of heat accumulation is small in the limited time, in order to achieve a higher efficiency on very low temperature environment for the operation of the heat pump system, many measures must be taken to strengthen the heat exchange of the heat-storage evaporator. |
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