EFFECTIVENESS OF TWO DIFFERENT EVAPORATIVE COOLING SYSTEMS IN A SYNTHETIC WARMED AIR SPACE

Document Type : Original Article

Authors

1 Professor, Agric. Eng. Dept., Faculty of Agriculture, Kafrelsheikh University, Egypt.

2 Assistant Professor, Agric. Eng. Dept., Faculty of Agriculture, Kafr elsheikh University, Egypt.

3 Graduate Student, Agric. Eng. Dept., Faculty of Agriculture, Kafr elsheikh University, Egypt.

Abstract

Heat stress inside farm structures such as animals and poultry farms in addition to greenhouses is one of the major problems facing the producers in this field. Such problem is virtually occurred at the time of hot waves during which just ventilation process could not the appropriate action and the need for an immediate step in is urgent. Evaporative cooling systems serve as a one solution to alleviate heat stress and contribute in controlling the environment inside the structure. Therefore the present study has aimed to stand on the effectiveness of two different evaporative cooling systems namely pad–fan and misting systems in a synthetic warmed air space. An artificial ventilation system was tested simultaneously to emphasize the necessity of cooling the ventilation air. Experimental setup of three similar greenhouse models representing the synthetic warmed air space each was equipped with a one system and instruments were installed on a roof of a dwelling at Ariamoon village near Kafr elsheikh city, Kafr elsheikh Governorate, Egypt (31.18°N, 30.91°E). Pad-fan system was investigated at 10 and 5 cm pad thickness of a manually constructed pad material made of a balanced (1:1) mixture of rice straw and palm leaf fibers (kerina). Misting system was investigated at 207 and 103 kPa (30 and 15 psi) nozzle pressure. Different airflow rate (Q) levels ranged from 0.042 to 0.155 m3/s were applied. Air temperature (T) and relative humidity (RH) were detected on hourly basis for three days as repetitions for each treatment. To stand on the effectiveness and cooling potential of both evaporative cooling systems, temperature reduction (∆T), saturation efficiency (SE), Specific temperature reduction (∆T/Q), unit evaporative cooler performance (Unit ECP) and water consumption were calculated and showed. The results revealed a ∆T ranged from 0.4 to 2.12oC and from 0.38 to 3.49°C for pad-fan and misting systems respectively. RH of the cooled air ranged from 90.8 to 98.6% and from 88.9 to 97.97% for pad-fan and misting systems respectively. SE, ∆T/Q and Unit ECP beyond 78%, 41°C.s/ m³ and 10 kW/°C respectively were reached with the most higher values belong to misting system. The artificial ventilation system caused a temperature rise and failed at least to keep the temperature as it is outside. Accordingly and under the current experimental conditions the misting system revealed to have the merit in cooling effectiveness. In addition, the attractive advantage of saving water and its appropriateness in playing a considerable role in irrigation technology under the protected agriculture. 

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References

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Website: https://hvac-library.blogspot.com/p/digital-psychrometric-chart.html (accessed on 2015)
Misr Journal of Agricultural Engineering
Volume 35, Issue 4
October 2018
Pages 1473-1492

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