2. Adiabatic water-cooling tower You have been requested to redesign an adiabatic water-cooling tower that has...

  

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2. Adiabatic water-cooling tower You have been requested to redesign an adiabatic water-cooling tower that has a blower with a capacity of 6.20 x 10 ft/hr of entering moist air from the surroundings. The moist air enters typically at 75.5 F and a wet-bulb temperature of 65.5 F. The exit air is to leave at 93 F and 82.5 F wet bulb. For this question, please show your work by attaching your psychrometric chart. (a) (8 pt) How much liquid water can be cooled in pounds per hour if the water to be cooled enters the tower at 125 F and leaves the tower at 88 F? Assume that the moist air is not in contact with the liquid water to be cooled. In other words, the water to be cooled is in a pipe entering and exiting the cooling tower with perfect heat transfer (no energy losses). Use the psychrometric chart attached (or pg 434 of textbook) and a constant heat capacity for liquid water of CPH) = 1.0 Btu/lbm F. State any assumptions made. Hint: A sketch of the process may help with your analysis. (b) (7 pt) Assuming that the dry air flow remains constant, what is the mass of water vapor in the entering moist air (in pounds per hour) and mass of water vapor in the leaving moist air? Where do you think this extra water vapor is coming from? dry air (0F, 1 atm) Reference states: HO (liquid, 32F, 1 atm), 02 ab Enthalpy at saturation a per pound of dry air 30% 130 65.5% Dry Bulb Temperatur Humid Volume, Dry Air 2. Adiabatic water-cooling tower You have been requested to redesign an adiabatic water-cooling tower that has a blower with a capacity of 6.20 x 10 ft/hr of entering moist air from the surroundings. The moist air enters typically at 75.5 F and a wet-bulb temperature of 65.5 F. The exit air is to leave at 93 F and 82.5 F wet bulb. For this question, please show your work by attaching your psychrometric chart. (a) (8 pt) How much liquid water can be cooled in pounds per hour if the water to be cooled enters the tower at 125 F and leaves the tower at 88 F? Assume that the moist air is not in contact with the liquid water to be cooled. In other words, the water to be cooled is in a pipe entering and exiting the cooling tower with perfect heat transfer (no energy losses). Use the psychrometric chart attached (or pg 434 of textbook) and a constant heat capacity for liquid water of CPH) = 1.0 Btu/lbm F. State any assumptions made. Hint: A sketch of the process may help with your analysis. (b) (7 pt) Assuming that the dry air flow remains constant, what is the mass of water vapor in the entering moist air (in pounds per hour) and mass of water vapor in the leaving moist air? Where do you think this extra water vapor is coming from? dry air (0F, 1 atm) Reference states: HO (liquid, 32F, 1 atm), 02 ab Enthalpy at saturation a per pound of dry air 30% 130 65.5% Dry Bulb Temperatur Humid Volume, Dry Air