Research on optimal ratio of solar-ground source heat pump system in severe cold and semi-arid region of Northwest China

By studying the optimal ratio of solar-ground source heat pump (SGSHP) systems in the severe cold and semi-arid region of Northwest China, the goal of improving the system performance is achieved. Taking the residential buildings in Baotou as the model, three different modes of the combined operation of solar and ground-source heat pumps are simulated. The results show that the performance of the mode in which one part of the collector side is connected to the outlet end of the buried pipe and the other part is connected to the outlet end of the heat pump unit is the best. The COP of the system after 20 years of operation has decreased from 5.48 to 4.99, which decreases by 9%. The load ratio and the split ratio of the circulating fluid are proposed. When the collector side takes about 40% of the total heat load, the COP is the highest, which increases by 1.45% compared with the COP of 5.48 under the optimal mode. When the split ratio on the collector side is 0.6, the average COP before optimization is increased by 6.8%.