COOLING TOWER TERMS
Cooling Range
The difference in temperature between the hot water entering the tower and the cold water leaving the tower is the cooling range.
The difference in temperature between the hot water entering the tower and the cold water leaving the tower is the cooling range.
Approach
The difference between the temperature of the cold water leaving the tower and the wet bulb temperature of the air is known as the approach
The difference between the temperature of the cold water leaving the tower and the wet bulb temperature of the air is known as the approach
Wet bulb temperature
Temperature as indicated by a thermometer the bulb of which is kept moist by wick over which air is circulated. This is theoretically, the lowest temperature to which water can be cooled and it depends on the dry bulb temperature and relative humidity of the ambient air.
Temperature as indicated by a thermometer the bulb of which is kept moist by wick over which air is circulated. This is theoretically, the lowest temperature to which water can be cooled and it depends on the dry bulb temperature and relative humidity of the ambient air.
Drift
Water droplets that are carried out of the cooling tower with the exhaust air. Drift droplets have the same concentration of impurities as the water entering the tower. The drift rate is typically reduced by employing baffle-like devices, called drift eliminators, through which the air must travel after leaving the fill and spray zones of the tower. Proper tower design can minimize drift loss.
Water droplets that are carried out of the cooling tower with the exhaust air. Drift droplets have the same concentration of impurities as the water entering the tower. The drift rate is typically reduced by employing baffle-like devices, called drift eliminators, through which the air must travel after leaving the fill and spray zones of the tower. Proper tower design can minimize drift loss.
Dry bulb temperature
External outdoor temperatures as indicated by a dry bulb thermometer in degree C.
External outdoor temperatures as indicated by a dry bulb thermometer in degree C.
Heat Load
The amount of heat to be removed from the circulating water within the tower. Heat load is also an important parameter in determining tower size and cost. It is of primary importance that an accurate heat load determination be made. If the heat load calculations are low the cooling tower will be undersized. If the calculations are high, oversized more expensive equipment will result.
The amount of heat to be removed from the circulating water within the tower. Heat load is also an important parameter in determining tower size and cost. It is of primary importance that an accurate heat load determination be made. If the heat load calculations are low the cooling tower will be undersized. If the calculations are high, oversized more expensive equipment will result.
Ton
An evaporative cooling ton is 3024 kcal/hr.
An evaporative cooling ton is 3024 kcal/hr.
Effectiveness=Range/(Range+ Approach)
Makeup
The amount of water required to replace normal losses caused by blow down, drift, and evaporation.
The amount of water required to replace normal losses caused by blow down, drift, and evaporation.
Cooling tower Location selection
Cooling tower Location selection
When selecting the location, sufficient clearance should be allowed for the free flow of air to the inlet of the tower and for its discharge from the tower. Obstructions will reduce airflow causing a reduction in capacity.
When selecting the location, sufficient clearance should be allowed for the free flow of air to the inlet of the tower and for its discharge from the tower. Obstructions will reduce airflow causing a reduction in capacity.