The Numerical Analysis Of The Soil Heat Transfer Based On Ground-coupled Heat Pump With Seasonal Heat Storage

In recent years, with the development of the heat pump, advocacy and requirements of building energy conservation, the progress of urbanization and the improvement of people’s living standard, ground source heat pump project with its own advantages in the domestic to be rapid spread. This also marks the ground source heat pump industry has entered a golden age of development. However, geothermal energy also has some limitations, one of the most prominent problems is that the imbalance of soil heat storage, which is caused by the imbalance of whole year air-conditioning hot and cold load, makes the system efficiency decline. Especially in northern areas, this contradiction is particularly outstanding, and how to make the underground heat storage capacity to achieve balanced, has become a problem to be solved.Example, in the north residential,cooling load per unit area in summer is around80w, per unit area heat load in winter is about45w, the energy consumption of per unit area in the summer is much higher than the winter. But air conditioning period in summer is generally60days, winter heating period generally is110days, per unit time in summer a lot of heat is stored in the ground, but total amount is less; per unit time in winter less heat is taken from the ground, but total amount is large. Which triggered a series of questions, such as:In the design of ground heat exchanger is based on peak or total, according to summer or winter. From the perspective of different operating conditions of ground source heat pump system, this paper tries to discuss a method which not only can maintain underground heat balance but also can solve the problems discussed above.First, the ground source heat pump system operation principle is analyzed, summarized a series of operating characteristics of ground source heat pump system, obtained that different operating parameters on the system operation, especially long-term operation has a critical influenceSecond, through simulation, we analyzed the energy efficiency of ground source heat pump system under different operating parameters.Third, through the analysis of the practical examples, it is concluded that the feasibility of this method.The results show that when the summer cooling water supply and return water temperature changed from28℃/32℃to40℃/45℃, COP of the system would decrease, but a lot of heat would be stored in underground, enhanced the soil temperature, solved the problem of hot and cold load imbalance, improved the operating efficiency of the system in winter. At the same time, the same operating condition of condenser in summer and winter is very favorable to the maintenance and long-term use of the unit. The technical difficulties of the program is how to improve the circulating fluid temperature of ground source side in summer and at the same time, don’t let the unit COP reduce (see chapter Ⅱ).To solve this problem, the efficiency and economic parameters of ground source heat pump on different operating conditions were simulated, and through the analysis knows that the best cooling water supply and return water temperature in summer is36℃/41℃.