Ground source heat pump (GSHP) systems have been used worldwide in buildings because of their advantages of highly efficient performance in terms of energy and environment for space cooling and heating; however, cooling demand is predominant in tropical climates. This paper reviews of the GSHP systems applications in Southeast Asia; several applications of GSHP in Thailand, Indonesia, Malaysia, Singapore, and Vietnam have been addressed. Experiments were initiated in 2006 in Kamphaengphet; the latest experiment found in the Scopus searching tool is the GSHP simulation in Kuantan in 2019 using EnergyPlus using the ground loop design software. GSHP systems have the potential to be used in Southeast Asia despite the dominance of cooling demand, leading to a thermal imbalance within the subsurface. This imbalance can reduce the performance of the system; however, groundwater flow is considered as a key factor in preventing the effect of thermal distribution owing to GSHP operation. These results suggest that the GSHP has the potential to reduce emissions and electricity consumption within areas having tropical climates, such as Southeast Asia, for sustainability and future generation.

Groundwater has been widely used in Thailand for many purposes, including agricultural activities; therefore, groundwater can be contaminated and affect the environment and human health. One of the most commonly applied and imported pesticides is atrazine, which is an herbicide used to control annual broadleaf and grass weeds in sugarcane. Monitoring and reducing the atrazine leaching potential into groundwater would play an important role in preventing this problem. The aim of this study is to evaluate the leaching potential of atrazine in Song Phi Nong District, Suphan Buri Province, via the attenuation/retardation factor model (AF/RF model) and the groundwater ubiquity score (GUS). It was found that most of the agricultural areas, especially the sugarcane fields, had high leaching potential due to the low adsorption and water holding capacity of the soil. The performance of the model was then evaluated by the result of nitrate (NO₃⁻) detection in groundwater, which has been reported to be a pesticide and herbicide leaching indicator. Interestingly, the area with high leaching potential was partly contaminated by high NO₃⁻ concentration. However, some factors relating to leaching potential in the area were not considered in the model, causing low nitrate concentration detection. The isotopic ratio was also measured in this study to identify sources of NO₃⁻; most of the nitrate in the groundwater samples, as a result, was polluted by human activities, especially from domestic wastewater. The AF/RF model can be a risk management and groundwater resource planning assistant, leading to human health and environmental protection related to pesticide-contaminated groundwater.

Atrazine is widely used as a herbicide to control annual broadleaf in agricultural area such as rice and sugarcane. It is considered as one of endocrine disrupting chemicals. Atrazine also affects liver, the central nervous system, immune system and cardiovascular function. The study area is sugarcane field in U-thong and Song Phi Nong district, Suphan Buri province. In this area, soil and groundwater samples were collected at eight different points distributed over the sugarcane area with different soil types. Batch adsorption experiment was carried out to evaluate the proper adsorption isotherm of each soil. Additionally, groundwater samples were analyzed for nitrate concentration. For the leaching potential assessment, AF/RF model was used because the model requires only basic parameters of the pesticide and soils. AF/RF model is tier-1 model using for defining pesticide leaching index for preliminary assessment in the area with the limited data availability. The result of batch sorption experiment indicated that soil samples were well fitted with Freundlich isotherm. Kf was found in the range of 0.284 to 0.822 L/Kg. Additionally, 1/n was reported in the ranged of 0.401 to 0.855. High nitrate concentration was also found in groundwater in the range of 3.25 to 71.11 mg/L. As a result from AF/RF model, most of the area was considered as high leaching potential for atrazine and nitrate in this study area. Moreover, there also were soil samples with low to moderate leaching potential due to the different soil types and sorption behaviors. The detected nitrate concentration conforms to the leaching potential of S1, S2, S4, S5 and S6. In the other words, the result of the leaching potential model showed 62.5% efficiency as a model performance.