Heating, Cooling And Economy Analysis Of Solar-ground Coupled Heat Pump System In Cold Regions

The civil building heat load in cold regions is much higher than its buildingcold load. The ground-source heat pump system is widely used for indoor heatingand cooling in the suburbs where city heating network is absent. Due to the heatabsorption capacity from ground is far greater than its heat storage capacity, it willcause the decrease of soil temperature year by year, and destroy the soil ecologicalbalance. Meanwhile, heat pump operation performance will reduce year by year.Thispaper studies the solar-ground source coupled heat pump (SGCHP) system whichstores the solar energy from transition season and summer in the ground, and takethe energy out in winter for indoor heating. Due to the solar energy take a large partof heat storage capacity, the disorder of the heat absorption and the heat storage issolved, which avoids the reduce of soil temperature from year to year and improvesthe heat pump operation performance.The main design concept of the SGCHP system is: in order to make full use ofthe solar energy resources, use solar energy directly for heating when solar energyresources are abundant in winter, and open the heat pump unit when the solar energycannot meet the requirements of indoor heating; in order to make full use of naturalresources, use ground cold source directly for indoor cooling, and open the heatpump unit when the ground cold source cannot meet the requirements; store thesolar energy from transition season and summer through the plate heat exchanger inthe ground for winter use. Firstly, the system operation mode design was completedaccording to the design concept. Secondly a target building in Beijing was selected.Then the building dynamic heat load was simulated. At last the preliminary designof the SGCHP system based on simulation results was completed.This paper mainly uses the TRNSYS transient simulation program for thedynamic simulation of the established SGCHP system. The system operatingcharacteristics are studied mainly from the following aspects: heat storage capacityin the heat store mode, the variation of the inlet and outlet temperature of the groundheat exchangers in the heat store mode; indoor temperature in the cooling mode, thevariation of the inlet and outlet temperature of the ground heat exchangers in thecooling mode, the performance of heat pump in the cooling mode; indoortemperature in the heating mode, the variation of the inlet and outlet temperature ofthe ground heat exchangers in the heating mode, the performance of heat pump inheating mode; the annual temperature variation characteristics of ground. At last,This paper analyzed the economical benefits of the SGCHP system with the annualcost value method, and compared with traditional ground source heat pump(GSHP) system to seek the feasibility of use for the system in cold regions.This paper proposed the plan of application of the SGCHP system in coldregions to solve the actual problems of ground source heat pump in ordinaryresidential buildings for heating and cooling, and studied the actual operatingcharacteristics and economical benefits of the system through simulation whichplayed a certain reference for the application of SGCHP system in cold regions.