Water desalination using heat pumps

The USA/Mexico border areas have very limited water resources with salinity a major problem. Experimental work on heat pump assisted water purification has been carried out in Mexico since 1981. Initially, electrically driven mechanical vapor compression heat pumps were used. These were subsequently replaced by absorption heat pumps with the objective of developing systems to operate on environmentally clean low grade heat energy. These thermally driven units can either be designed as small scale mobile units to be used in disaster areas or scaled up in size to produce potable water for cities at a cost competitive with reverse osmosis and electrodialysis technologies. Future work will concentrate on heat driven heat transformer or temperature amplifier systems since these are the most promising from an economic and environmental point of view.