Cooling tower operation for problem

10 A cooling tower 20 X 20 feet cross section was sized to cool 2300 gpm of water from 115 to 82°F, when the 5% wet-bulb temperature is 65°F. The maximum air rate that can be delivered is 400,000 cfm. Determine the number of transfer units needed to meet process conditions. 

12 A cooling tower has a cross-sectional area of 8000 ft2. The unit is designed to handle 1500 gpm of water from 112 to 92°F when the 5% wet-bulb temperature is 85°F. The air rate is 310,000 cfm. At full loadings, a test was run where it was observed that at a wet-bulb temperature of 70°F the water range was from 72 to 83°F. Determine whether the tower was fulfilling the conditions of the guarantee. 

Stewart and E. N. Lightfoot. Transport Phenomena (New York John Wiley Sons, Inc., 1960). 

Cheremisinoff, P. N., and R. A. Young. Pollution Engineering Practice Handbook (Ann Arbor, MI Ann Arbor Science Publishers, Inc., 1975). 

Process Heat Transfer (New York McGraw-Hill Book Co. 1950). 

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