Combined desalination and solar-assisted air-conditioning system

Analysis of a new desalination process utilizing low grade thermal energy is presented. In this process. fresh water is distilled from saline water under near-vacuum pressures created by passive means. enabling low-temperature distillation with lower energy requirements. The energy for low-temperature distillation is provided by a thermal energy storage (TES) system maintained at 55 degrees C utilizing any low grade waste heat source. In this study, heat rejected by the condenser of a modified absorption refrigeration system (ARS) is evaluated as a possible source to drive this desalination process. The energy for the generator of the ARS is provided by a combination of solar collector system and grid power. Results of this study show that the thermal energy rejected by an ARS of cooling capacity of 3.25 kW (0.975 tons of refrigeration) along with an additional energy input of 208 kJ/kg of desalinated water is adequate to produce desalinated water at an average rate of 4.5 kg/h. This energy consumption is competitive with that of the multi-stage flash distillation process of similar capacity (338 kJ/kg). An integrated process model and performance curves of the proposed approach are presented in this paper. Effects of process parameters on the performance of the system are also presented. (C) 2008 Elsevier Ltd. All rights reserved.