Introduction

Typically, the primary goal of a cooling tower thermal performance test is to determine the cooling capacity of a cooling tower when operated at its design conditions of water flow, range, fan motor power (mechanical draft), dry bulb temperature (natural draft), and barometric pressure. 

For a mechanical draft tower, cooling capability is defined as the ratio of circulating water flow rate (corrected to design fan motor power consumption) to the predicted water flow rate as determined by the cooling tower manufacturer’s performance curves. Because the manufacturer’s performance curves are equivalent representations of the tower performance at various operating and environmental conditions, the predicted water flow rate is the flow rate of a cooling tower with 100% capability. Thus, the ratio of predicted water flow rate to the adjusted circulating water flow rate is a constant which means tower capability is a constant despite testing at off design conditions. Said another way, the cooling tower test translates the performance of the tower at test conditions to an equivalent performance at design conditions.