Essay On Cooling Tower

The purpose of this experiment is to compare the effects of three variables, air flow rate, air temperature, and water flow rate, on cooling ability of a slatted, counter-current cooling tower. Additionally, the three variables will be compared based on the closure of a water mass balance and energy balance of the cooling tower.

In a slatted, counter-current cooling tower, warm water enters the top of the tower and flows down a series of slatted inserts inside of tower. An air source is introduced at the base of tower, which flows up the tower. As the air interacts with water flow on the slats, the temperature differences causes evaporation. Water’s change from a liquid to a gas phase requires a large amount of energy, approximately 2326 kJ/kg at atmospheric conditions, which provides a cooling effect to the water [3].

Theoretically, the water loss rate should be equal to the water flow rate from the water make-up tank, which can be represented by and overall water mass balance,

L_(make-up)+G_inlet (H_inlet )=G_outlet (H_outlet ) (1) where L_(make-up) is the mass flow rate of the water from the make-up tank, G_inlet is the mass flow rate of air at the inlet, H_inlet is the humidity of the air at its inlet, G_outlet is the mass flow rate of air at the outlet, and H_outlet is the humidity of the air at its outlet. The amount of make-up water needed for the system can be calculated by determining the loss of water due to evaporation. Using a mass balance of the air flow in tower, the mass flow rate of the water loss, L_loss, can be represented by,

L_loss=G_outlet-G_inlet (2)

The mass flow rate of air at the inlet and outlet of the cooling tower can be calculated