Thermal Contribution Rates of Double-Heat Sources of the Direct-Expansion Solar-Ground Source Heat Pump System in Hot Summer and Warm Winter Area

According to the energy-consuming characteristics of buildings in hot summer and warm winter area, a direct-expansion solar-ground source heat pump system is put forward. This system runs the direct-expansion solar heat pump system in summer and direct-expansion solar-ground source heat pump system in transition season and winter to produce hot water. The article analyses the thermal contribution rates of double-heat sources of the system under various working conditions in different seasons. Results indicate that the total area of solar evaporators matches the power of units and the matching value is 2.18m2/kW. When the average daily total solar radiation is 15.8MJ/m2 in summer, 11.2MJ/m2 in transition season and 11.2MJ/m2 in winter, the unit area heat transfer are respectively about 1.48kW/m2, 1.1kW/ m2 and 0.43kW/m2. The annual solar thermal contribution rate is 46.4% and the annual soil thermal contribution rate is 32%, which can reduce 57.96% quantity of heat absorbing from the soil.