22 May 2008

ANALYSIS OF A GROUND SOURCE HEAT PUMP SYSTEM OPERATION UTILIZING STEEL FOUNDATION PILES AS GROUND HEAT EXCHANGERS


A ground source heat pump (GSHP) system has been installed into a new building
in Soen Campus of Sapporo City University. The GSHP system uses steel foundation piles
as the ground heat exchangers. The construction works were carried out based on the
design by using a design tool for GSHP systems that the authors have developed. The
system has operated and the authors has analysed the system since April 2006.
The result showed that steel foundation piles used as ground heat exchangers injected heat
of around 250 W/m to the ground at the maximum during the cooling period. Also, it is
expected the GSHP system in this building can operate with high efficiency for long term due
to the ground water flow. The GSHP system can operate with average COP of more than 4.5
and reduce CO2 emission of 40% compared to a gas boiler system.