EWT를 고려한 지중열교환기 파이프 선정에 관한 연구

Abstract

This paper proposes an optimum pipe material (PVC vs. PE) design & selection foropen loop ground heat exchangers. Heat exchange efficiency and/or workability, andthe need for trench insulation were investigated by comparing EWT (cooling mode) ofeach system. CFD simulations for the PVC and PE pipe with the same inner diametershow similar EWT. This is because the PVC pipe has a small thickness but a lowthermal conductivity as compared to the PE pipe, and thus these two properties tendto offset each other. However, a hypothetically insulated pipe led to a meaningfuldrop of EWT. This means pipe insulation is of importance in performance of groundheat exchangers. From analyzingclimate data and system operation, it is notadvantageous to insulate trench pipes due toconstruction difficulties and ground temperature characteristics that are seasonally varied.