Greenhouse technology is a viable option for sustainable crop production in the regions of adverse climatic
conditions. During hot seasons the heat input to a greenhouse causes the internal temperature to exceed its optimal value.
The present study was devoted to construct an evaporative cooling system to reduce heat stress inside a greenhouse. Two
identical small-scale greenhouses were designed, constructed, and installed on an open roof of a domestic house. The two
greenhouses were cooled using fan-pad system. In addition, a thin water film was applied on the roof of one greenhouse to
study the effect of roof water film and fan-pad (combined system) on the cooling performance. The two cooling systems were
compared under the same condition. Three new evaporative cooling pads represented by Cryperus Alopecuroides Rottb
(Samar), Cyerus Alternifolius (Purdy) and Cyperus Rotundus l (Nut-grass or Se’d) were adapted and evaluated. Three pad
face air velocities ranged between 0.45 and 1.01 m s-1 and two thicknesses of 10 and 15 cm were used in the investigation of the
cooling performance criteria. Results showed that the proposed cooling pads in the suggested evaporative cooling systems
were able to maintain acceptable microclimatic conditions for greenhouse models. Se’d pad material proved more efficiency
in temperature reduction. It was revealed that the temperature inside the greenhouse operated under the combination of roof
water flow and fan-pad system was less than that for fan-pad greenhouse by about 1.1 to 5.44° C in the morning and afternoon
respectively. The air relative humidity was increased due to humid effect provided by cooling system which protects crops
from excessive transpiration and crop damage. The daily average cooling efficiencies of 88.4, 83.1 and 79.6% were obtained
for Se’d, Purdy and Samar, respectively during testing days inside the combined system at 15 cm pad thickness and 0.45 m s-1
pad face air velocity. The Se’d pad material showed the highest efficiency as compared to other pad materials and could be
used as an alternative pad material.