Application Of Horizontal And Vertical Ground Loops Coupled To Ground Source Heat Pump Systems

About soil heat imbalance caused by ground source heat pump,we generally improve soil temperature field by using cooling tower for auxiliary heat dissipation where the cooling load dominates,which is helpful to some extent.The depth of the horizontal pipe is relatively shallow,more convenient for heat exchange with the environment around,which makes the heat transfer efficiency higher than that of the cooling tower in summer.Based on this,a kind of horizontal buried pipe instead of cooling tower is proposed in this thesis to solve the thermal imbalance caused by vertical buried pipe type ground source heat pump,and also presents an analysis of the applicability in typical area.In this paper we built an office building,selected 12 typical cities,and adjusted the thermal performance and other parameters according to the "public building energy efficiency design standard",the simulation result shows: In Shenyang,Dalian,Yinchuan and Lanzhou,the heating capacity is far greater than the cooling capacity,and the ratio of accumulative cooling and heating load is less than 0.5,which makes them suitable for composite ground source heat pump system with auxiliary heating equipment.The ground source heat pump system simply with vertical buried pipe can basically ensure the heat balance of soil in Chengde and Taiyuan where accumulative cooling and heating load ratio is between 0.5 and 1.The cumulative load ratio is between 1 and 1.5 in Tianjin and Shijiazhuang,there is little difference between the heat absorption and discharge of the soil,whether install auxiliary cooling equipment or not is according to the soil property.In Tianjin area,where the soil thermal conductivity is greater than 2.25W/(m·K),auxiliary cooling equipment is unnecessary,neither in Shijiazhuang area where the soil thermal conductivity is greater than 2.4W/(m·K),otherwise,according to the whole life cycle economic calculation,it is feasible to use horizontal and vertical coupled ground source heat pump system to solve the thermal imbalance of soil.Where the cumulative cooling and heating load ratio is between 1.5 to 2 such as in Zhengzhou,Xi'an and Jinan.Zhengzhou is suitable for horizontal and vertical coupled ground source heat pump system according to its soil property,as well as in Xi'an where the soil thermal conductivity is less than 1.9W/(m·K)and less than 2.1 W/(m·K)in Jinan.When the cooling and heating load ratio is above 2,compared with the cooling tower composite ground source heat pump system,the horizontal and vertical coupled ground heat pump system can not meet the peak load demand in summer without increasing the land area,so it's not applicable in this kind of area due to the large difference between the cooling and heating load.