ISHS Acta Horticulturae 257: Energy Conservation and Solar Energy Utilization in Horticultural Engineering
COOLING OF GREENHOUSES IN TROPICAL AND SUB-TROPICAL CLIMATES |
| Author: | K.V. Garzoli |
| Abstract:
Unlike heating, for which the technology is well established and straightforward, greenhouse cooling frequently presents considerable problems. A proper understanding of the thermal behaviour of greenhouses can, in most cases, lead to the development of systems that give satisfactory performance under all but the most extreme conditions. Natural ventilation can be used to good effect in many cases, and large and suitably placed ventilators are frequently all that is required, sometimes in combination with a partially reflective shade screen to prevent the entry of solar radiation that is superfluous to the plant's requirements. Evaporative cooling is normally the most effective means of greenhouse cooling. The method of calculating evaporative cooling capacity, as described in this paper, has been found to give very good results under most conditions. Ducts should be located low in the greenhouse (preferably under benches or on the floor) in order to minimize the degree of mixing with hotter greenhouse air before reaching the plants. | |
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