The Feasibility Study On Ground Source Heat Pump Heating System With Air Source Ground Thermal Storage In Severely Cold Region

In severe cold region, the heating load of building in winter is much larger than its cooling load in summer ,so GSHP must take much heat from soil in winter to satisfy the heating requirements, year after year, which would lead to declining of soil average temperature, and the system coefficient of performance would decrease too. The paper presents air source ground thermal storage system. It can store the quantity of heat of high temperature air in summer into the soil with the outdoor heat exchanger and vertical U tube ground heat exchanger to compensate the heat extracted by the heat pump in winter, and to maintain balance of the soil temperature field, which effectively uses the summer natural heat, therefore it has strong energy-saving significance.In order to accurately study the performance of air heating source thermal storage and its feasibility as the GSHP auxiliary heat source, in this paper established the air source ground thermal storage heat pump heating system test-bed, and monitored the performance of thermal storage of the summer high temperature air heating system and performance of heat pump heat extraction in winter, and systematically analyzed soil temperature field changes in the process of heat storage, recovery and extraction one year; in theoretical research, established the mathematical models of vertical single U-tube, heat pump unit, fan coil unit, verify the accuracy and reliability of mathematical model of different parts of the system under certain conditions, then programmed the system annual dynamic simulation model using Matlab software, and simulated the whole year operation of the system in Harbin, Changchun and Shenyang, and analyzed the characteristics of heat storage and heat extraction of soil, compared the economy of this system with conventional GSHP system in Harbin after year-round operation.This study shows that to some extent the air source geothermal storage system balance the soil temperature field, and the coefficient of performance of the GSHP with air source geothermal storage is higher than the conventional GSHP system when running all year round in those cities, especially when running in Harbin for several years, the system coefficient of performance is obviously higher than that of the conventional GSHP system, with the low running cost, which prove that the new system is feasible for building heating in severe cold region.The paper provided some theoretical basis for the application air heating source ground thermal storage heat pump heating system in cold region, a lot of basic data for in-depth study of the system, and to a certain extent could be a reference for engineering applications.