Operation strategy of solar-ground source heat pump systems

Establishes a solar-ground source heat pump system model according to the climatic conditions in Tianjin. Carries out a simulation study of the system based on TRNSYS program, analyses the energy consumption of the system and the ground temperature change, and studies the operation strategy with emphasis. Selects an appropriate operation strategy based on the coefficient of performance (COP) of system, i.e. to turn on the solar collection pump as the temperature difference between collector outlet and tank outlet is higher than 15 ℃, and to turn off the pump until it is less than 2 ℃, and to turn on the solar storage pump when tank outlet temperature is higher than 50 ℃, and to turn off it until the temperature difference between inlet and outlet of the borehole heat exchanger is less than 5 ℃.