Thermal conductivity of backfill materials for inground heat exchangers
Conference
·
OSTI ID:113293
- Univ. of Idaho, Moscow, ID (United States). Dept. of Mechanical Engineering
The thermal conductivity of the material immediately surrounding the heat exchangers in a vertical borehole directly affects the performance and costs of a ground-coupled heat pump (GCHP) system by regulating the flow of energy to or from the ground. Many properties of the backfill material such as moisture content, composition, specific heat and density influence the thermal conductivity. The thermal conductivities of a wide variety of pure backfill materials and mixtures were measured. All the materials examined were compared with a standard bentonite backfill. Saturated natural sandy soil was the backfill material with the highest thermal conductivity. One attractive mixture consists of a pure silica sand, acrylic latex, and graphite. This mixture forms a solid backfill around the heat exchanger. Yet, the attractiveness of any backfill material combination remains very location and application dependent, varying with the native soils at the site, and the mode in which the GCHP is to be used.
- OSTI ID:
- 113293
- Report Number(s):
- CONF-950336--; ISBN 0-7918-1300-2
- Country of Publication:
- United States
- Language:
- English
Similar Records
Ground-coupled heat pump loop design using thermal conductivity testing and the effect of different backfill materials on vertical bore length
Effect of backfilling material on ground coil performance
Effect of backfilling material on ground coil performance
Conference
·
Thu Oct 01 00:00:00 EDT 1998
·
OSTI ID:649411
Effect of backfilling material on ground coil performance
Conference
·
Wed Dec 31 23:00:00 EST 1986
·
OSTI ID:6186271
Effect of backfilling material on ground coil performance
Conference
·
Mon Jun 01 00:00:00 EDT 1987
· ASHRAE Trans.; (United States)
·
OSTI ID:6367942