Theoretical And Experimental Study On Solar-Ground Coupled Heat Pump With Seasonal Storage

This paper presents a solar-heat pump combisystem which combines solar energy seasonal storage technology with ground source heat pump system. Solar energy and shallow ground energy can be utilized fully in this system. Heat storage makes it possible to use solar energy after sunset or in winter, so the whole system performance is improved. Besides, this solar combisystem can overcome the disadvantages of intermittence, unreliability, daily & seasonal variation and low radiation flux of solar energy.Heat storage of solar energy in soil is concerned closely with heat transfer in soil. The ground temperature field,the thermal storage performance and its representative parameters such as daily heat storage, average heat storage ratio, heat loss ratio, and the inter-seasonal storage performance are analyzed. A VB computer program was developed, and numerical simulations were carried out. The feasibility of the combisystem of solar - ground coupled heat pump with seasonal storage in Tianjin was analyzed to provide theoretical foundation for practical applications.A demonstration project of SGCHPSS was set up and a data acquisition system was developed. Based on simulation results and weather conditions in Tianjin, the design scheme of thermal storage was presented, which realized energy cascaded utilization inter-season by storing the aboundant solar energy on the underground soil in summer and taking out in winter. Primary operation results of system performance were abtained, including temperature variation of inner tube and outer tube, the durative time, the storage power and energy consumption power. The simulation results showed good agreements with the experimental data.