Numerical Evaluation of Heat Transfer un Ground Heat Exchanger Considering Flow through U-loop

파이프 순환수의 수치해석 모사를 통한 수직 밀폐형 지중열교환기 단면의 열전달 효율 평가

This paper presents a series of numerical simulations on the thermal performance and sectional efficiency of a closed-loop vertical ground heat exchanger (U-loop) equipped in a geothermal heat pump system (GHP). A 3-D finite volume analysis (Fluent) was used to simulate the operating process of the closed-loop vertical ground heat exchanger by considering the effect of the thickness of HDPE pipe and grout thermal properties, distance between the inflow and outflow pipes, and the effectiveness of the latticed HDPE pipe system. It was observed that the thermal interference between the two strands of U-loop is of importance in determining the efficiency of the ground heat exchanger, and thus it is highly recommendable to modify the cross section configuration of the conventional U-loop system by including a thermally insulating latice between the two strands.