Single stage absorption chillers (water/lithium bromide) can operate using low grade heat, thus single stage absorption chillers can operate using low temperature geothermal resources. An EES computer model was written for the single stage absorption chiller based on overall heat transfer coefficients, mass flows, salt balances, energy balances and other assumptions. The single stage model was calibrated with well known and available data from US and Japanese manufacturer. The system was considered to work in hot and humid climate like Abu Dhabi and Shanghai. The results show that in the case when cooling water is 28°C hot the initial and annual total cost is high. However, as cooling water temperature decreases the initial and annual total cost decreases sharply (when cooling water is at 20°C the reduction is around 35% of total annual cost). The results show great influence of cold and hot water on the performance and total annual cost of absorption chiller. A second part of a computer model contains a Total Equivalent Warming Impact (TEWI) analysis. TEWI considers both, the direct refrigerant effect and the primary energy impact on the equivalent carbon dioxide (CO2) emission.