Application of absorption heat pumps to multi-effect distillation: a case study of solar desalination

The coupling of a double-effect absorption heat pump and a multi-effect distillation unit was demonstrated at the Plataforma Solar de Almería (CIEMAT), Spain, within a solar desalination research project. Improvements that were identified have been implemented in a new prototype within the framework of the European project entitled AQUASOL (March 2002 – February 2006). The prototype, which will be tested during the demonstration phase of this project, is expected to consume about half of the multi-effect distillation unit but at a higher temperature, 180 °C. This paper points out different advantages of coupling an absorption heat pump to a multi-effect distillation system which could significantly increase the competitiveness of both conventional and solar powered multi-effect distillation plants. In addition, this paper shows that intensive research should be carried out for optimising and assessing such a desalination system.