Cooling of greenhouses using seawater: a solar driven liquid-desiccant cycle for greenhouse cooling in hot climates

P.A. Davies, I. Harris, P.R. Knowles

Research output: Chapter in Book/Published conference outputConference publication


Evaporative pads are frequently used for the cooling of greenhouses. However, a drawback of this method is the consumption of freshwater. In this paper it is shown, both theoretically and through a practical example, that effective evaporative cooling can be achieved using seawater in place of fresh water. The advantages and drawbacks of using seawater are discussed more generally. In climates that are both hot and humid, evaporative systems cannot always provide sufficient cooling, with the result that cultivation often has to be halted during the hottest months of the year. To overcome this, we propose a concept in which a desiccant pad is used to dehumidify the air before it enters the evaporative pad. The desiccant pad is supplied with a hygroscopic liquid that is regenerated by the energy of the sun. The performance of this concept has been modelled and the properties of various liquids have been compared. An attractive option is to obtain the liquid from seawater itself, given that seawater contains hygroscopic salts such as magnesium chloride. Preliminary experiments are reported in which magnesium chloride solution has been regenerated beneath a solar simulator.
Original languageEnglish
Title of host publicationProceedings of the international symposium on greenhouse cooling
EditorsB.J. Bailey
Place of PublicationAlmería (ES)
PublisherInternational Society for Horticultural Science
Number of pages8
ISBN (Print)978-90-66056-19-0
Publication statusPublished - 30 Sept 2006
EventInternational Symposium on Greenhouse Cooling - Almería, Spain
Duration: 24 Apr 200627 Apr 2006

Publication series

NameISHS Acta Horticulturae
PublisherInternational Society for Horticultural Science
ISSN (Print)0567-7572


SymposiumInternational Symposium on Greenhouse Cooling


  • evaporative cooling
  • desiccant cooling
  • solar energy


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