개방형 지열 시스템 설계 방법의 개선 및 적용

Abstract

In recent years, the utilization of geothermal energy for buildings has increased significantly. Among the existinggeothermal energy systems, open loop systems show better efficiency than closed loop systems because of the direct heat exchangewith groundwater or surface water. On the other hand, there are a lack of technical and institutional standardized procedures for thedesign of open loop systems. Therefore, this study proposes an improved design method of an open loop geothermal system using theborehole thermal resistance based on the result of a numerical study using a commercial finite element program (COMSOLMultiphysics). The borehole thermal resistance obtained using the numerical study was 43% lower than that calculated using theexisting method. Consequently, the proposed design method can reduce the design length of a ground heat exchanger by approximately5%. Similar trends of a lower borehole thermal resistance (42%) and shorter design length of the ground heat exchanger (2%) werealso observed in the application of the proposed design method to the open loop system in a military facility.