Performance of a day/night water heat storage system for heating and cooling of semi-closed greenhouses in mild winter climate

E.J. Baeza, J.J. Pérez Parra, J.C. López, J.C. Gázquez, D.E. Meca, C. Stanghellini, F.L.K. Kempkes, J.I. Montero

Research output: Chapter in Book/Report/Conference proceedingConference paperAcademicpeer-review

4 Citations (Scopus)

Abstract

A novel system for heating/cooling greenhouses based on air/water heat exchangers connected to a thermally stratified water storage tank was tested in a small greenhouse compartment at the Experimental Station of the Cajamar Foundation in Almería, Spain. The system maintained a closed greenhouse (no natural ventilation) throughout the winter and spring during which a truss tomato crop was grown. Atmospheric CO2 concentration could be maintained during the daytime allowing for greater net photosynthesis in relation to a reference greenhouse in which traditional natural ventilation was used to control temperature and humidity. Three fine wire heat exchangers (Fiwihex®) were installed 1 m above the crop when at full development. The heat exchangers allowed for a very efficient transfer of the sensible and latent heat accumulated in the compartment. During the winter, the daytime temperatures were maintained below the ventilation set point (30°C). During the night, the system was able to maintain temperatures above the heating set point (12°C), with stored warm water temperatures between 15 and 17°C after clear days. After cloudy days, with water temperatures between 11 and 13°C, the system could always keep a temperature gradient with the exterior of 4-6°C, enough to maintain greenhouse air temperatures above 8°C the entire night. When seasonal night air temperatures exceeded the heating set point, the hot water at the top of the tank was cooled to the wet bulb temperature by means of an open cooling tower. The cooled water was used for cooling the greenhouse, which allowed for closing the greenhouse for a longer period. The water condensate during the cooling mode, allowed for a high water saving and maintained the relative humidity very constant during the day (around 80%). During the night, humidity was kept at 90% without ever reaching saturation.
Original languageEnglish
Title of host publicationISHS 28th Int. Horticultural Congress - Science and Horticulture for People (IHC 2010): International Symposium on Greenhouse 2010 and Soilless Cultivation
EditorsN. Castilla, O. van Kooten, S. Sase, J.F. Meneses, W.H. Schnitzler, E. van Os
Place of PublicationLisbon, Portugal
PublisherISHS
Pages535-542
Volume927
ISBN (Print)9789066057241
DOIs
Publication statusPublished - 2012
Event28th International Horticultural Congress -
Duration: 22 Aug 201027 Aug 2010

Conference

Conference28th International Horticultural Congress
Period22/08/1027/08/10

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