Document Type : Original Article
Authors
1
MSc. graduated of Water Structures, Department of Nature Engineering, Agricultural Sciences and Natural Resources University of Khuzestan, Khuzestan, Iran.
2
Associate Professor, Department of Nature Engineering, Agricultural Sciences and Natural Resources University of Khuzestan, Khuzestan, Iran.
3
Assistant Professor, Department of Nature Engineering, Agricultural Sciences and Natural Resources University of Khuzestan, Khuzestan, Iran.
Abstract
Introduction
In order to reduce the amount of evaporation from water reservoirs, various methods have been proposed, which can be divided into two physical and chemical categories. In the physical methods, by using physical coverings, such as floating balls, metal and polymer plates, or tree leaves, and by covering the water surface, evaporation waste is greatly reduced. These covers reduce a large amount of solar energy reaching the water surface and reduce vapor transmission by slowing the air flow.
Methodology
The present study was conducted with the aim of investigating the effect of the coverage and shape of polypropylene sheets on reducing the evaporation rate and the effect of meteorological variables on the efficiency of these sheets efficiency. This research was carried out in two parts, in the first part, the efficiency of square and triangular polypropylene plates was investigated in comparison with floating balls, and in the second part, the efficiency of 100, 70, 50, and 30% coverage of polypropylene plates was evaluated.
Results and discussion
The results obtained from the tests showed that in the conditions of using floating balls, the reduction of evaporation was more intense and this coating was able to reduce evaporation to a greater extent compared to square and triangular floating plates. Also, using the square and triangular polypropylene plates and floating balls reduced evaporation by 30.71%, 14.86% and 48.7%, respectively, compared to the control pan.
Conclusions
The results of two-way ANOVA on different meteorological variables showed that the percentage of relative humidity, which was the most important factor in evaporation from the pan, lost its significance due to the presence of floating balls and polypropylene sheets on the water surface. The comparison of rectangular covers with different densities showed that by increasing the density from 30, 50 and 70% to 100% respectively, evaporation decreases by 2.3, 1.5 and 0.8 times.
Keywords
Main Subjects
)