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Thermal Diffusivity Measurement of Backfilling Materials for Horizontal Ground Heat Exchanger Using Dual-Probe Method  

Sohn, Byong-Hu (Green Building Research Division, Korea Institute of Construction Technology)
Choi, Hang-Seok (School of Civil, Environmental and Architectural Engineering, Korea University)
Publication Information
Journal of the Korean Society for Geothermal and Hydrothermal Energy / v.7, no.2, 2011 , pp. 51-59 More about this Journal
Abstract
Storage and transfer heat in soils are 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 measured results of the thermal diffusivity of soils(silica, quartzite, limestone, sandstone, and 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 and volumetric heat capacities using dual-probe method and (ii) compare the estimates from 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. Measurements made by using the dual-probe method agreed well with independent estimates obtained using the single-probe method.
Keywords
Thermal diffusivity; Backfilling materials; Horizontal ground heat exchanger; Dual-probe method;
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Times Cited By KSCI : 6  (Citation Analysis)
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