2009 Volume 60 Issue 9-10 Pages 469-489
Worldwide use of geothermal heat-pump (GHP) has extensively grown in recent two decades. Although generally geothermal heat-pump system may not have thermal merit for space cooling in tropics, there may be some places in tropical regions where subsurface can be used as “cold heat-source”. In order to confirm this possibility, subsurface temperature surveys were widely conducted in the ChaoPhraya plain, Thailand.
As a result, the distribution of subsurface thermal gradients has marked differences between the lower and the upper plain. Thermal gradients in the upper plain are low, and most of them are below 1.0 oC/100 m. The thermal gradients in the lower plain, on the other hand, are generally high and show a tendency of lower gradient at peripheral areas and higher gradient at central parts (4.0 oC/100 m). This subsurface thermal regime is due to thermal conduction by regional groundwater flow system in the lower plain estimated by chemical compositions and stable isotope variations.
