USE OF SOLAR THERMAL COLLECTORS FOR DISINFECTION OF GREENHOUSE HYDROPONIC WATER

Water disinfection is necessary to eliminate pathogens, as many horticultural products are to be consumed raw and in regions with high values of solar radiation it can be used for this purpose.
In this paper a disinfection system based on solar thermal energy is proposed.
The system consists of a solar collector that heats the drainage water from the greenhouse, achieving lethal temperatures for pathogens present in water.
Several solar thermal collectors as flat plate, Integrated Collector Storage (ICS), Compound Parabolic Concentrating (CPC), linear Fresnel lens type and vacuum tube collectors developed for domestic use, with minor changes in their design and operation, can be suitable for disinfecting water.
From laboratory scale experiments with an ICS collector, a minimum time period of three hours was observed for an effective disinfection treatment at 65°C. For solar collectors operating in higher temperatures, similar disinfection results can be achieved in a shorter time.
Alternative systems as the flat plate collectors with booster reflectors that achieve increased thermal output and the combination of ICS solar collectors with Fresnel lenses are also suggested, where the drainage water can be preheated through the absorbers of the placed Fresnel lenses on the greenhouse roof.

International Symposium on High Technology for Greenhouse System Management: Greensys2007

Y. Tripanagnostopoulos, M.C. Rocamora

Water treatment, solar water heating, ICS systems, Fresnel lenses

https://doi.org/10.17660/ActaHortic.2008.801.87