Abstracts of presentations given on Tuesday, 18 July 2006, in session 6 of the UCOWR Conference.


This study evaluated the feasibility of utilizing low-grade heat sources such as solar energy and waste heat from industrial processes for desalination. The premise of the approach is that saline waters can be desalinated by evaporation and condensation of fresh water at near-ambient temperatures at low pressures. Low pressures can be achieved naturally in the head space of water columns of height equal to the local barometric head. By connecting the head space of such a saline water column to that of a distilled water column, and by maintaining the temperature of the former about 15-20 degrees C above that of the latter, fresh water can be evaporated from the saline column and condensed in the distilled water column. In this study, it is proposed to use thermal energy storage (TES) system to heat the head space of the saline water column. The TES can be maintained at the desired temperature using solar energy and/or waste heat from thermal power plants, refrigeration plants or air conditioning units. This paper presents an integrated process model developed to evaluate the feasibility of combining solar energy with an absorption refrigeration system (ARS) to provide the energy to the TES. Results of this study show that the heat rejected by an existing ARS of cooling capacity of 3.25 kW (~1 ton of refrigeration) is adequate to produce desalinated water at a rate of 5 kg/hr, with an additional energy input of 150 kJ/kg of desalinated water. The total solar panel area required for this application was 25 m2 . Performance curves and guidelines for preliminary design of such an integrated system are presented.