Abstract
Some experiments on the controling methods for greenhouse temperature in summer were conducted.
(1) Mist and fan evaporative cooling system was most effective among cotrol methods of summer greenhouse temperature, such as natural ventilation with or without shading materials, forced ventilation and the evaporative cooling methods.
It was recognized from the results of observation that is inside temperature 3.0 to 6.0 degree higher in natural ventilation, 2.5 to 3.0 degree higher in forced ventilation, 1.5 to 3.5 degree higher in natural ventilation with shading cloth, and approximate equal in the evaporative cooling methods as compared with outside air temperature, respectively.
(2) Temperature difference of inlet and outlet of ventilating air in the evaporative cooling glasshouse was enlarged by solar energy considerably.
(3) Solar transmittance ratio into glasshouse, were found to be 60 to 75% without blind, 30 to 45% with shading cloth (1.6mm opening, #600, black) and 25 to 30% with marsh-reed blind.
(4) The spray effciency or cooling efficiency in the evaporative cooling system was analysed to be about 1 gram per 1kg air rate in the mist room and 51.2 gram per 1kg air rate in the glasshouse.
Improvement of the cooling efficiency and reducing of the temperature difference in a glasshouse with evaporative cooting system will be next problems of atmost importance.
