| Recently, with the development of solar thermal utilization and heat pump technology, the technology of hot water supplied by solar energy become the focus of research and development in energy field gradually. Accordingly, Direct-Expansion Solar-Assisted Heat Pump Water Heater(DX-SAHPWH) technology is popularized step by step. However, as far as DX-SAHPWH technology, some problems are left to be researched thoroughly .This paper conduct the study of the auto-control technology of DX-SAHWPH system, focusing on the study of control scheme and strategy, and development the Micro-Controller of DX-SAHPWH system, as well as the control performance.In this paper, the main works are summarized as follows:Firstly, aiming at the characteristics of the climate condition and the rural & urban architecture, a miniature and practical DX-SAHWPH specimen system is built.Secondly, according to the experimental research on DX-SAHWPH system, thermal dynamics analysis is conducted, and control requirements of DX-SAHWPH system are put forward.Thirdly, according to the performance of DX-SAHWPH and the control demand, a central Micro-Control system is designed independently to achieve the throttling control of the refrigerant and the capability control of the compressor of the DX-SAHWPH system, including the SCH design,PCB design,software arithmetic,software compilation and the hardware & software debugging.Fourthly, experimental research is conducted on the DX-SAHWPH system, and control performance is analyzed. In the process of functioning, the hardware & software designs are improved to make DX-SAHWPH system run more safely,stably and reliably, and also more accordant with the function rule of DX-SAHWPH system.Finally, based on the research results, practicable schemes are put forward, including such as the selection of aim super heat, the frequency matching of the compressor, the establishment of control scheme, parameter deciding, and so on.
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