2010 Volume 32 Issue 4 Pages 229-239
Ground-coupled heat pump (GCHP) systems are considered to be one of the most energy efficient air-conditioning systems. In Japan, however, use of the GCHPs is still limited because of a lack of information on the advantages offered by these systems and because of their high initial costs. The accurate estimation of heat exchange rates, which can minimize the initial cost of the GCHP systems, is therefore of crucial importance to enhance the distribution of the system.
The geological condition and groundwater flow strongly affect the heat exchange rates of ground heat exchangers (GHEs). These rates can be maximized and the installation costs of the GCHP systems can be reduced by developing suitability maps based on local hydrogeological information. Such maps were generated for the Fukui Plain, Hokuriku District, using field-survey data and a numerical modeling study.
First, a field-wide groundwater and heat transport model was constructed for the area and the results were matched against measured groundwater levels and vertical temperature profiles. Four kinds of thematic maps were prepared using the results from numerical model and hydrogeological information. Finally, suitability maps for GCHP system were developed using index overlay model with thematic maps. Suitability maps indicated that suitabilities for GCHP system in the Fukui Plain are strongly correlated with the depth of groundwater table and the ratio of sand-gravel in the formation.
