| Along with the rapid development of architectural industry in China, building energy consumption is taking increasingly larger proportion in the total energy consumption in China; under such circumstances, the building energy efficiency and environmental protection have attracted more attention from people. The first energy shortage, in particular, has enabled people to realize that building energy efficiency is the most potential, direct and effective way to alleviate energy crisis among all the energy-saving measures. The application of renewable energy is the most effective way for building energy efficiency. To fully take advantage of the solar energy resources, energy conservation and environment protection in Jinzhou, this paper offers a study of multi-unit combined operation solar energy solar heating system controlled by DDC, a system consisting of glass evacuated collector tube solar energy distribution unit, hot water tank and heat pump unit.From the perspective of organic combination of solar energy and heat pump, this paper provides a multi-unit combined operation solar energy heating system and method to address the low utilization rate and fraction of solar energy. This system and method can adopts different heating operation strategies at different time in order to meet the all-weather demands for heating in the building. The following studies have been conducted in this paper:(1) A model for individual building of experimental platform is established through DeST software and the dynamic thermal loading during the heating period is calculated, thus obtaining the rules for hourly change of heat loading within a year and determining the design load of the system.(2) The experiment studies the heating collection-heat accumulation characteristics of the solar heat pump system as well as the influence of different month, different water yield, different solar radiation intensity and different initial temperature of heat accumulation on this characteristic.(3) This experiment researches the heating characteristics of the solar heat pump system and analyzes the thermal load characteristics of the experimental architecture so as to probe into the different month and water capacity on the heating system and systematically expound on the characteristics of solar fraction during the heating period.(4) It offers a comprehensive research on the heating characteristics of the combined operation of system and the evaluation of the enhancement of solar energy utilization rate by heat pump and an analysis of the economical and energy-saving properties of the system.Through the above-mentioned experimental research, this paper comes to the following conclusions:(1) The DeST software is adopted for analog computation. Under the condition of typical meteorological station, the heat load index for experimental platform buildings is 24.9W/m2.(2) in the researches into the collection-accumulation characteristics, the heat-collecting temperature usually grows by 21℃~36℃ in each month. The soar heat pump system further reduces the initial temperature of temperature collection and enhances the efficiency of the system. The experimental researches on heat-collection and accumulation of different water capacity generate the best water storage capacity, thus maintaining the highest solar fraction of the system.(3) In the researches on heating characteristics of different months during the heating period, the average thermal load in each month ranges from 0.76kW~1.54 kW with heat pump system operating in November, December, January and February, auxiliary electric heating in December and January, the maximum value of COPH of the heat pump system of 7.25 and the average COPH of 4.(4) During the whole heating period and based on the working condition under typical weather, the operation of heat pump ensures that the final solar fraction reaches 92.9% in November, 81.3% in December, 71.8% in January, 94.2% in February and 94.6% in March. According to the real-time data of the system, the operation of solar heat pump has increased the solar energy utilization rate by 44.9%. Even in the coldest December and January, the solar fraction still amounts to 20% under the operation of solar heat pump, a fact that provides scientific basis for the application of solar heat pump to solar heating system. On the basis of the experimental platform and with the auxiliary conventional energy of electricity, the carbon dioxide emission reduction is 2481.7kg, which testifies to the good effect of emission reduction. |
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