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In order to reduce electricity consumption, the vertical loop geothermal heat pump (GHP) system coupled with a normal air conditioner was installed in an experimental room in the Parot Racha Building, Chulalongkorn University, Bangkok, Thailand for a comparative, long-term measurement program. The decrease in electricity consumption was approximately 30%. On the basis of the data derived from our measurements, the underground temperature seemed to be consistent and lower than the average outside air temperature, over two years. The underground system consisted mainly of two 50-m-long drilling wells and pipes with a total length of 170 m. The well performance was not examined, but both soil and groundwater aquifer (Bangkok aquifer) at 25 to 50 m. could be utilized for the cooling operation. Moreover, the major controlling factors of electricity consumption were found to be the outside air temperatures and the underground water circulation temperatures. In addition, we considered the geology, underground temperature, and aquifer of Bangkok concluding that almost all Bangkok areas are suitable for GHP installation, except for those where the subsurface temperature is too high compared with the outside air temperature.

The cooling of spaces in tropical regions, such as Southeast Asia, consumes a lot of energy. Additionally, rapid population and economic growth are resulting in an increasing demand for space cooling. The ground-source heat pump has been proven a reliable, cost-effective, safe, and environmentally-friendly alternative for cooling and heating spaces in various countries. In tropical countries, the presumption that the ground-source heat pump may not provide better thermal performance than the normal air-source heat pump arises because the difference between ground and atmospheric temperatures is essentially low. This paper reports the potential use of a ground-source heat pump with horizontal heat exchangers in a tropical country—Thailand. Daily operational data of two ground-source heat pumps and an air-source heat pump during a two-month operation are analyzed and compared. Life cycle cost analysis and CO2 emission estimation are adopted to evaluate the economic value of ground-source heat pump investment and potential CO2 reduction through the use of ground-source heat pumps, in comparison with the case for air-source heat pumps. It was found that the ground-source heat pumps consume 17.1% and 18.4% less electricity than the air-source heat pump during this period. Local production of heat pumps and heat exchangers, as well as rapid regional economic growth, can be positive factors for future ground-source heat pump application, not only in Thailand but also southeast Asian countries.

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An experimental geothermal heat pump system for space cooling was installed in Kamphaengphet, Thailand in 2006 and used for 17 months. Temeprature changes in the subsurface heat exchange tube and its surroundings were monitored to evaluate subsurface thermal properties and short-and long-term effects of operation of the system. Subsurface temperuatre increase due to the system operation recovered in few days and no long-term effect was observed after a year of operation. Room and atmospheric temperatures and electricity consumprion of the system were also measured through the period. Temperatures and flow rates of primary and secondary fluids were measured as well. As a result, a system COP (coefficient of performance) of around 3 was obtained for its stable operation period. The results of temperature measurements and calculation of system performances is presented in this paper.

Viviparidae fossil collected from the R-, Q-, and K-coal zones of the Mae Moh coal mine, northern Thailand were analyzed for 13 Carbon and 18 Oxygen isotopes at Akita University, Japan. The result reveals that Viviparidae of the lower part of the coal mine contribute much heavier carbon isotopes than the upper part. The results revealed that Viviparidae shell O ‰ value between -6.64 to -7.04 ‰ PDB. The isotopic results of Viviparidae fossil shells from Mae Moh basin show the gradually change from the R-coal zone to the Q-, and the K-coal zone and significantly different from the Recent Viviparidae in the area. The heavy carbon isotopes in the R-coal zone could imply a much cooler climate than during the Q-and K-coal zone depositing period and the area were more close to the sea. The climatic condition during the Q-and K-coal zone depositing period was warmer and at a geographically higher elevation or latitude than during depositing the R-coal zone. The changing records in Mae Moh coal field are confirmed by temperate fossils in the other Oligocene to Lower Miocene basins in Northern Thailand. The change to a more tropical climate could have occurred during the Middle Miocene period, as indicated by paleomagnetic age dating in the K-and Q-coal zone. The northward movement of the Australian-Indian plate and collision with the Eurasian plate are suspected to be the main cause of the change.

The deployment of highly efficient cooling equipment is expected to promote energy savings and greenhouse gas emissions reductions in the tropics. A ground source heat pump (GSHP) has high energy-savings potential for use in Bangkok, Thailand. This study aimed to elucidate the operational conditions of a GSHP when used in Bangkok which was expected to achieve a higher efficiency than an air source heat pump (ASHP) over the long term. An operational experiment on a pilot facility in Bangkok and a simulation over a three-year GSHP operation were conducted. As a result of the operational experiment and simulation, the proposed operational condition was that the 90th percentile value of the hourly heat pump (HP) inlet temperature did not exceed 5 °C above that of the hourly annual ambient temperature during the third year of operation. When a GSHP designed based on this condition was utilized for a small government building, the required number of boreholes were 24, 4, and 3 for air-conditioned areas of 200, 40, and 25 m2, respectively, which achieved 40% energy savings. Thus, a small-scale GSHP in Bangkok designed based on the proposed condition can achieve high efficiency within space limitations.