ISHS Acta Horticulturae 263: International Symposium on Simple Ventilation and Heating Methods for Greenhouses in Mild Winter Climates
DUCTED-AIR HEATING SYSTEMS IN GREENHOUSES: EXPERIMENTAL RESULTS |
| Authors: | J.F. Meneses, A.A. Monteiro |
| Abstract:
An horticultural complex made of twenty six double span ellyptic arched greenhouses was fitted with air heating systems designed to use olive husk as energy source. To achieve good temperature distribution two polyethylene ducts were planned to deliver the heated air above the tomato crop in each greenhouse. Temperature distribution was measured in a 64 m long greenhouse during cold nights. Variations of air temperature in length, width and height were recorded and compared with outside air temperatures and the thermostat set temperature. The discharged air temperature gradient along the duct was also measured. The largest temperature differences were registered between readings taken near the two opposite end walls. Air Temperature was always higher near the heater. The best uniformity was registered along the greenhouse width. | |
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