# A Study on Thermal Conductivity Properties of Ground Heat Exchangers for GSHP systems

• 백성권 (코오롱건설(주) 기술연구소) ;
• 전중규 (코오롱건설(주) 기술연구소) ;
• 안형준 (코오롱건설(주) 기술연구소)
• 발행 : 2007.11.30

#### 초록

Cement mortar and concrete can be used as grouts but problems regarding shrinkage and the discord of coefficients of thermal expansion between grouts and HDPE pipes has to be solved. Thermal conductivities of wet condition two times larger than those of dry condition, except for pure cement mortar. The addition of sand into the cement grouts greatly increases the thermal conductivity. The addition of bentonite into the cement grouts reduces thermal conductivity thus reducing the density. Bentonite grouting must be used only below the groundwater table since bentonite grouts possesses high shrinkage property in dry condition. The addition of sand prevents the shrinkage of bentonite grouts. Bentonite manufactured in Korea can be used since they possess similar thermal conductivities with imported products. The addition of sand into the bentonite grouts greatly increases the thermal conductivity.