Research On Refrigeration In Summer And Heating In Winter Based On Parabolic Trough Solar Collector System

Solar energy is a very promising resource to meet energy demand without affecting the environment.In summer,the application of solar energy in air conditioning refrigeration has many advantages,among which the good seasonal matching is the best.The cooling demand is the largest and the refrigeration capacity of the system is also the greatest in summer.In winter,if solar energy was well collected and utilized in heating,it could also reduce the consumption of non-renewable source and electric power greatly,so that the environmental pollution caused by the burning of conventional fuels such as coal could be well alleviated.In summer,the principle and experimental process of solar single-bed adsorption refrigeration system with parabolic trough collector and adsorbent bed of vacuum collector tube were introduced.The zeolite molecular sieve and water was used as working pair.A series of optimization studies on this refrigeration system made by our research group in recent years are summarized.In order to extend the refrigeration time of the system,a double-bed solar adsorption refrigeration system was designed based on the optimized single-bed system.The overall design of the double-bed system includes the important sub-components and the circulation pipeline.The performance of the double-bed system was predicted by analyzing the cycle time and the evaluation index.In winter,with forced air circulating in the vacuum collector tube and the pipeline,a solar air heating system with parabolic trough collector was designed and built used the original experimental equipment in summer.From November 15,2017 to January 15,2018,the small parabolic trough collector with automatic tracking control system and the vacuum collector tube were used as heating source of the system to heat the indoor air of the test room.By measuring the air temperature at outlet of the collector tube and the heating room,the practicability of heating with small parabolic trough collector was studied,and the heating efficiency of the system was calculated and analyzed.The results show that the parabolic trough collector has a high heating efficiency,can reach more than 60% for most of the day.During the winter heating period,the solar heating time reached to 5 to 7 hours a day for a simple insulated room in Beijing under the solar air heating system,which indicates the practical value of the system.Parabolic trough collector and the vacuum collector tube are the core component of solar collector system.In the last,the physical and mathematical model of the air flow in vacuum collector tube is established.Based on the measured data of the air heating experiment in winter,the boundary conditions of the model are determined.The variation of air temperature on the outlet section of the collector tube is analyzed and the accuracy of the model is verified by comparing the simulation results with the experimental results.