Dynamic Heat Transfer Analysis on the New U-type Medium-Deep Borehole Ground Heat Exchanger

The U-type medium-deep borehole ground heat exchanger BGHE is a new form of utilization geothermal energy and there has been relatively little research on it. This paper introduces the structure working principle BGHE. control equations based characteristics transfer model are established creatively. initial boundary conditions circulating fluid rock soil determined. And reliability simulation verified through comparing simulated results with engineering data. Based above theoretical foundation, effects flow rate, gradient thermal conductivity different layers nominal extraction outlet temperature examined. changes in surrounding vertical pipe at inlet analysed. corresponding reasons these revealed. It shown from that rate opposite influence temperature. increasing terrestrial conducive to transfer, but reverse occurs during process. will hardly affect continuous use buried exchanger. study beneficial better understand its impact soil. promote popularization application energy.