Experimental And Simulation Study Of Solar Hot Water System Assisted By Heat Source Tower Heat Pump

The rapid development of economy caused the enormous depletion of energy and increasing deterioration of ecological environment,the energy crisis and ecological pollution promote the development and utilization of renewable energy.As a kind of common renewable energy,the use of solar energy can effectively relieve the energy crisis and control environmental pollution.Making domestic hot water is an important way of solar energy utilization,however,the use of solar energy is influenced by the weather,so it needs assistant heat source when we make domestic hot water.A solar hot water system assisted by heat source tower heat pump was built.In this paper,the author studies the solar hot water system assisted by heat source tower heat pump by experimental testing and simulation analysis.First,the author builds an experimental apparatus and tests the performance of the system,and tests and analyses the thermal performance of three typical conditions(independent operating condition of solar hot water system,operating condition of solar hot water system assisted by heat source tower heat pump,independent operating condition of heat source tower heat pump system).Secondly,the author makes the simulation model of the system based on TRNSYS,calculates a series of thermal performance parameters of solar hot water system assisted by heat source tower heat pump in Changsha,and analysis hourly,daily,monthly and annual thermal performance of the system.In the end,the author optimizes the system,and obtains optimum angle and azimuth of solar collector in Changsha area.In the paper,the water temperature,solar fraction,contribution rate of heat source tower heat pump of the system are tested and simulated in Changsha.the test results show that the thermal performance of the three kinds of operating conditions is good during the test,solar fraction is 46.69%and the temperature of tank is 50℃during the test.Simulation results show that temperature of the water supplied to users is 45℃,solar fraction exceeds 57%and heat collection efficiency is maximum throughout the year which exceeds 33%in July、August and September,the annual heat collection efficiency is 29.13%,annual solar fraction is 33.99%,while annual contribution rate of heat source tower heat pump is 66.01%,The system has a certain energy saving potential.Results of optimization analysis show that optimum angle of solar collector is 15°,and optimum azimuth of solar collector is 30° which is 30° in the direction of south by west in Changsha area.