INFLUENCE OF TWO NEW GREENHOUSE COVERING MATERIALS ON GREENHOUSE MICROCLIMATE AND COOLING LOAD
Aim of this paper was to study the effects of a new polyethylene (PE) film with high reflectance and absorption in near infrared radiation (NIR-PE) and of a new PE film with low transmittance in infrared radiation IR (IR-PE), on greenhouse microclimate and cooling load of a hydroponic tomato crop. Films were evaluated in the laboratory and experimentally in three similar arched roof greenhouses, two covered with the new covering materials and the third one by a common PE film (C-PE). The greenhouse and outside microclimate parameters along with crop growth and production were recorded. Laboratory measurements show that in the total radiation band the NIR-PE film has 13% lower transmissivity than the other two films and 57% higher absorptivity than the C-PE film. Experimental results show that the NIR-PE covering material reduces significantly the solar radiation entering the greenhouse and resulted in a temperature drop up to 2°C than the air temperature of the C-PE covered greenhouse. The total production per m2 was 12.12 kg, 12.00 kg and 10.25 kg under the IR-PE, the NIR-PE and the C-PE covered greenhouses, respectively with no significant differences between the three greenhouses.
Kitta, E., Bartzanas, T. and Katsoulas, N. (2012). INFLUENCE OF TWO NEW GREENHOUSE COVERING MATERIALS ON GREENHOUSE MICROCLIMATE AND COOLING LOAD. Acta Hortic. 952, 225-229
air temperature, relative humidity, energy saving