"PERFORMANCE OF GREENHOUSES IN THE ARABIAN GULF" Part I : Thermal Aspects

This work is devoted to the gaining of insight into the operation of environmentally controlled greenhouse in hot and humid climates. Field data inside and outside the greenhouse, namely: solar radiation, dry and wet bulb ambient temperature, relative mumidity, wind speeds, rainful and the three-dim.ensional greenhouse temperature disrtribution are presented over a two-year period the life project. Based on the local climatological conditions, the operational schedule of greenhouse equipment for; evaporative coolers, mechanical coolers, ventilators, gas heaters and shading is identified. In this locality, evaporative coolers adequately control the daytime greenhouse environment except for several hot and humid summer weeks. Mechanical coolers are required for summer nights. Gas heaters are only employed for cold winter nights. For this particular type of greenhouse where the pads are placed opposite to the fans, two temperature zones are identified. The lower zone, characterized by the height of the plant - which is less than pad height - maitains a temperature much lower than that of the upper one.