The Research Of Soil's Temperature Of Double U-Tube Ground Source Heat Pump And Economic Analysis Of The Heat Pump System

As one of new energy-conserving and environment-protected energy technologies, ground source heat pump may obtain massive regenerative energy by consuming less primary energy .when our country's energy supply is in growing tension , increasing attention has been paid to the ground source heat pump and people begin to promote its use. Based in ground source heat pump works of Tianjin Construction Committee energy-conserving building, this article studied temperature changes of soil surrounding double U-type vertical tube heat exchanger by testing soil's temperature in entire heating quarter. The analysis showed , double U-type vertical tube heat exchanger can affect the temperature of soil that is 1.5m-2.5m away from it ,that is , thermal radius of double U-type vertical tube heat exchanger is 1.5m-2.5m.when heat exchanged of well depth of units increases , thermal radius will increase.Studying soil's heat-storing and combining experiment ,this article calculated total heat that the ground source heat pump unit absorbs(emits) from(to) soil in winter(summer) ,and analyses the balance of the two ,and looks for the law of soil's temperature changes. the results showed ,after a year's operation of the system , the soil's temperature will rise by 2.3℃,and the same time ,this article proposed corresponding solutions, such as"underground pipes + cooling tower","Underground pipes + domestic hot water supply system"(applicable when heat absorbed from soil more than heat emitted to soil ) , or"underground pipes + auxiliary heating source"(applicable when heat emitted to soil more than heat absorbed from soil).Taking Tianjin Construction Committee energy-conserving building as an example , this article adopts BIN method and annual value of cost method to compare the initial capital costs and operation costs of several air conditioning schemes such as ground source heat pump,electricity refrigeration + heated by exchanger from municipal heat net and direct-fired lithium-bromide absorption-type refrigerating machine. The result indicates that the initial capital cost of ground source pump is higher than them of the others, but its operation cost and annual value of cost are the less , and its relatively more initial capital cost can be taken back in 2-3 years.