Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Thermal Conductivity of Cementitious Grouts and Impact On Heat Exchanger Length Design for Ground Source Heat Pumps
Design length and performance of heat exchangers for ground source heat pumps strongly depend on the thermal conductivity of the backfill material. Laboratory studies were undertaken to determine means of improving thermal conductivity of cementitious backfill grouts. The influence of fillers and admixtures was examined. Significant improvement of grout thermal conductivity was readily achieved through appropriate materials selection and mix design. Fillers such as silica sand, alumina grit, steel grit, and silicon carbide increased the thermal conductivity to values ranging from 1.7 to 3.3 W/(m ·K) (0.98 to 1.9 Btu/h·ft·°F). Neat cement grouts had conductivities of 0.80 to 0.87 W/(m ·K) (0.46 to 0.50 Btu/h·ft·°F). Filled cementitious grouts had better retention of thermal conductivity under drying conditions than bentonites and neat cements. The reduction in required bore length possible with cement-sand grouts was predicted theoretically for an example heat pump system and found to be 22 to 37%, depending on soil conductivity and bore diameter.
Thermal Conductivity of Cementitious Grouts and Impact On Heat Exchanger Length Design for Ground Source Heat Pumps
Design length and performance of heat exchangers for ground source heat pumps strongly depend on the thermal conductivity of the backfill material. Laboratory studies were undertaken to determine means of improving thermal conductivity of cementitious backfill grouts. The influence of fillers and admixtures was examined. Significant improvement of grout thermal conductivity was readily achieved through appropriate materials selection and mix design. Fillers such as silica sand, alumina grit, steel grit, and silicon carbide increased the thermal conductivity to values ranging from 1.7 to 3.3 W/(m ·K) (0.98 to 1.9 Btu/h·ft·°F). Neat cement grouts had conductivities of 0.80 to 0.87 W/(m ·K) (0.46 to 0.50 Btu/h·ft·°F). Filled cementitious grouts had better retention of thermal conductivity under drying conditions than bentonites and neat cements. The reduction in required bore length possible with cement-sand grouts was predicted theoretically for an example heat pump system and found to be 22 to 37%, depending on soil conductivity and bore diameter.
Thermal Conductivity of Cementitious Grouts and Impact On Heat Exchanger Length Design for Ground Source Heat Pumps
Allan, Marita L. (Autor:in) / Kavanaugh, Steve P. (Autor:in)
HVAC&R Research ; 5 ; 85-96
01.04.1999
12 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Unbekannt