A PILOT-SCALE STUDY FOR EVALUATING THE PERFORMANCE OF A FAN-PAD COOLING SYSTEM UNDER DIFFERENT CLIMATIC CONDITIONS OF SAUDI ARABIA | ||||
| Misr Journal of Agricultural Engineering | ||||
| Article 28, Volume 26, Issue 1, January 2009, Page 514-533 PDF (857.66 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/mjae.2020.110169 | ||||
 View on SCiNiTO | ||||
| Author | ||||
| Ibrahim M. Al-Helal | ||||
| Department of Ag. Eng., College of Food and Agriculture Sciences, King Saud University, P.O. Box 2460, Riyadh 11451, Kingdom of Saudi Arabia | ||||
| Abstract | ||||
| In the present study, a special test setup was designed to evaluate the performance of a fan-pad evaporative cooling system under different climatic conditions in Saudi Arabia. Weather data for Riyadh representing arid climate, Jeddah representing humid climate and Abha representing moderate climate were analyzed. These data contained hourly readings for air temperature, relative humidity and solar radiation. An evaporative cooler consisting of a 10 cm thick cooling pad, suction fan and water pump was used. The cooling pad was installed in a 1080mm high, horizontal duct of square cross-section insulated by 50mm polyurethane. The duct cross-section measures 1000mm ×1000mm. A variable speed suction fan was fitted at one end and the pad was designed so that the inlet air passed through the wetted pads. Air temperature and relative humidity of the inlet air were changed to simulate dry, humid and moderate climatic conditions of Saudi Arabia. The inlet air was heated by two types of electrical heater. The heaters were fixed in a contraction-cone-profile that is mounted in the air duct. The inlet air temperature was controlled by a PID temperature controller. Electrical high pressure steam boiler was used to produce low pressure steam for heating and humidifying the inlet air stream. The boiler capacity is 57 kg/h steam at a pressure of 5.5 bar. The weather data analyses showed that cooling of agricultural structures in Riyadh and Jeddah is very essential. The mean monthly temperature during summer in Riyadh area varies between 31.5oC and 36oC, and the relative humidity is between 14.4% and 20%. These conditions encourage the use of evaporative cooling. In Jeddah, the mean monthly temperatures during summer vary between 30oC and 33.5oC, and the relative humidity is between 57% and 82%. Cooling of agricultural structures in Abha is not necessary, except greenhouses that act as solar collectors. The mean monthly temperatures in Abha during summer vary between 22oC and 23.5oC, and the relative humidity was between 35% and 70%. Averages of monthly solar radiation levels during summer vary between 570 and 619 W/m2, for Riyadh, between 503 and 580 W/m2, for Jeddah, and between 477 and 591 W/m2, for Abha. Experimental results showed that averages of cooling efficiency were 82.4%, 72.2% and 75% under arid, humid and moderate conditions, respectively. The highest air temperature drop through the pad was observed under arid dry conditions with a range of 12-32.5oC. Whereas air temperature drop was lowest under humid hot conditions with a range of 2.8-8.6oC. The drop under moderate conditions ranged from 6 to 15.3oC. The maximum cooling of 20612W was obtained for the arid climatic conditions compared to 11883W and 5992W for moderate and humid climatic conditions, respectively. Cooling water consumption rate increased by increasing both temperature of the inlet air and air speed through the pads. The consumption rates were 11.8 and 13.8 l/hr at inlet air temperatures of 40 and 45oC, respectively, when air speed was 0.5 m/s. The rate increased from 8.8 l/hr at air speed of 0.25 m/s to 19.8 l/hr at air speed of 1 m/s when the air temperature at the inlet was 40oC. The water consumption decreased as the relative humidity of the inlet air increased at the same temperature. The water consumption rate decreased from 13.8 l/hr to 5.8 l/hr by increasing relative humidity from 8% to 58%, respectively, at inlet air temperature of 35oC. | ||||
| References | ||||
|
Al-Helal, I. M. and H. S. Al- Towejeri. 2001. Evaporative cooling for Palm Dates Fiber Pads and Cross-Flutted Cellulose Pads under Arid Conditions. Misr Journal of Agricultural Engineering, Vol. 18 No. (2): 469-483.
Al-Helal, I. M., N. Al-Abbadi, and A. Al-Ibrahim. 2004. A study of fan-pad performance for a photovoltaic powered greenhouse in Saud Arabian summer. International Agricultural Engineering Journal 13 (4): 113-124.
Ali A. K. A., A. A. Al-Haidary, and M. A. Alshaikh. 1999. The effect of evaporative cooling in alleviating seasonal differences in milk production of Almarai dairy farms in the Kingdom of Saudi Arabia. Asia Austral. Journal of Animal. 12 (4): 590-6.
Al-Sulaiman, F. 2002. Evaluation of the performance of local fibers in evaporative cooling. Energy Conversion and Management. (43): 2267–2273.
Arbel A, O. Yekutieli, and M. Barak. 1999. Performance of a fog system for cooling greenhouses. Journal of Agricultural Engineering Research. 72 (2):129-36.
ASAE. 2000. American Society of Agricultural Engineers. ASAE Engineering Practice 406.2, p.559-566. ASAE Standards. ASAE, St. Joseph, MI. 49085.
Bottcher, R. W., G. R. Baughman, R. S. Gates, and M. B. Timmons. 1991. Characterizing efficiency of misting systems for poultry. Transactions of the ASAE. 34(2): 586-590.
Bucklin, R., L. Turner, D. K. Bray and R. W. Hemken. 1991. Method to relieve heat stress for dairy cows in hot, humid climates. Applied engineering in Agriculture. 7 (2): 241-247.
Chen C. 2003. Prediction of longitudinal variations in temperature and relative humidity for evaporative cooling greenhouses. Agricultural engineering journal. 12 (3&4): 143-164.
Deaton, J. W., J. L. McNaughton, and B. D. Lott. 1982. Effect of heat stress on laying hens acclimated to cyclic versus constant temperatures. Poultry science. 61(5):875-878.
El-Nouty, F. D.; A. A. Al-Haidary; and M. S. Salah. 1990. Spray cooling effects on milk production; some blood parameters and thyroid hormones of Holstein cows in the semi-arid environment. Indian J Anim Sci. 63: 360-364.
Gates, R. S., J. L. Usry, and J. A. Nienaber. 1991. An optimal misting method for cooling livestock housing. Transactions of ASAE. 34 (5):2199-206.
Helsen, A. and J.Willmot. 1991. Wet air cooling of fruits, vegetables and flowers. Current practice in Europe. Technical innovation in freezing and refrigeration of fruits and vegetables. Paris, France: International Institute of Refrigeration. p. 169–77.
Jain, D. and G. Tiwari. 2002. Modeling and optimal design of evaporative cooling system in controlled environment greenhouse. Energy Conversion and Management. 43: (2235–2250).
Kittas, C., T. Bartzana and A. Jaffrin. 2001. Greenhouse evaporative cooling: measurement and data analysis. Transactions of the ASAE. 44(3): 683-689.
Lieo. C. and K. Chiu. 2002. Wind tunnel modeling the system performance of alternative evaporative cooling pads in Taiwan region. Building and environment 37: 177-187.
Montero, J. I.; T. H. Short; R . B. Curry and W. L. Bauerle. 1981. The influence of various water evaporation systems in the greenhouse environment. ASAE paper No. 81-4027.
Reece, F. N., J. W. Deaton, and L. F. Kubena. 1972. Effects of high temperature and humidity on heat prostration of broiler chickens. Poultry science. 51(2): 2021-2025.
Ryan, D. P., M. P. Boland and E. Kopel. 1992. Evaluating two different evaporative cooling management systems for dairy cows in hot, dry climate. Journal of Dairy Science. 75 (4):1052-9.
Umbarker S.P., R.S. Bonde, M.N. Kalase. 1991. Evaporatively cooled storage stature for oranges (citrus). Indian Journal of Agricultural Engineering. 1(1): 26–32.
Watt, J. R. 1953. Investigation Evaporative Cooling. Report U.S. Naval civil Engineering Research and Evaluation Laboratory.
Wiersma, F. and D. S. Benham, 1974. Design criteria for evaporative cooling. ASAE Paper No. 74-4527, ASAE, St. Joseph.MI 49085.
Zabeltitz, C. V. 2002. Ventilation and cooling of Greenhouses in Hot Arid Climate Presented at Second Protected Agriculture Regional Technical Coordination Meeting, Kuwait. | ||||
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