ISHS Acta Horticulturae 801: International Symposium on High Technology for Greenhouse System Management: Greensys2007
EFFECTS OF A SHADING AND AN INSULATING FOAM INJECTED BETWEEN DOUBLE POLYETHYLENE FILMS ON LIGHT TRANSMISSION, GROWTH AND PRODUCTIVITY OF GREENHOUSE TOMATO |
| Authors: | K. Aberkani, A. Gosselin, D. de Halleux, M. Dorais, X. Hao, J. Villeneuve, L. April |
| Keywords: | Temperature, solar radiation, artificial light, spectral quality, humidity, Lycopersicon esculentum, leaf gas exchanges |
| Abstract:
Energy saving in cold climates and excess light and temperature in summer are major concerns to the greenhouse industry. Sunarc of Canada developed a liquid foam technology allowing the generation and distribution of liquid foam between two polyethylene films used as greenhouse covering materials. The effects of such insulating and shading foams on energy consumption and greenhouse microclimate were investigated. Two greenhouses were used in this experiment: (1) a control greenhouse; and (2) a prototype greenhouse installed with the retractable foam technology. The first experiment (winter and early spring) consisted of injecting liquid foam between two films during the night to increase greenhouse insulation and decrease energy consumption. Tomato plants were grown using high-pressure sodium lamps (HPS) providing 120 μmol m-2 s-1 for 16 hours. In the second experiment (summer), liquid foam was in circulation between double polyethylene films during the day when solar radiation was high. Greenhouse climate (air and relative humidity), light transmission and spectral quality were measured in each greenhouse. In addition to saving in greenhouse energy consumption (40% to 60%), the results of this experiment indicated that the use of this technology as insulation, at night, increased artificial light reflection by 8% to 10% (300 nm to 1100 nm), which could contribute to the increase in leaves temperature. In summer, the circulation of liquid solution with or without foam as shading reduced natural light by 10% to 60% depending on the time of the day. Air temperature was reduced and relative humidity increased when the foam was applied for shading. | |
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