| Title |
Thermal Diffusivity Evaluation of Backfilling Materials for Horizontal Ground Heat Exchanger Using Single-Probe Method |
| Authors |
손병후(Byonghu Sohn) ; 최항석(Hangseok Choi) |
| Keywords |
열확산계수 ; 뒤채움재 ; 수평형 지중열교환기 ; 단일 탐침법 Thermal diffusivity ; Backfilling materials ; Horizontal ground heat exchanger ; Single-probe method |
| Abstract |
Storage and transfer heat in soils is governed by the soil thermal properties and these properties are therefore needed in many engineering applications, including horizontal ground heat exchanger for ground-coupled heat pumps. This paper presents the evaluation results of the thermal diffusivity of soils (silica, quartzite, limestone, sandstone, granite, and two masonry soils) used for the trench backfilling materials of the horizontal ground heat exchanger. To assess this thermal property, we (i) measure the soil thermal conductivities using single-probe method and (ii) use the de Vries method of summing the heat capacities of the soil constituents. The results show that the thermal diffusivity tends to increase as dry soil begins to wet, but it approaches a constant value or even decreases as the soil continues to wet. Combined algorithm with an improved model for the thermal conductivity of soils and the constituent equation provides accurate estimates of the soil thermal diffusivity. |