Abstract
The applicability of geothermal heat pumps in tropical region was investigated in this study based on subsurface temperature surveys. Although generally a geothermal heat-pump system may not have thermal merit for space cooling in tropics, there may be some places in tropical regions where the subsurface can be used as "cold heat-source".
In order to confirm this possibility, subsurface temperature surveys were widely conducted in the Chao-Phraya Plain, Thailand. In some cities, subsurface temperatures lower than monthly mean maximum atmospheric temperature by 5 °C or more over four months were identified. Thus underground may be used as cold heat-source even in parts of tropical regions.
