There are three types of cooling towers in HVAC:
- Open Cooling Towers
- Closed Circuit Cooling Towers
- Evaporative Condensers
Open Cooling Towers
Open Cooling Towers are a proven and cost effective method of cooling condenser water loops and industrial processes. In operation, the condenser water (or process water) flows directly over the heat transfer surface of the Open Cooling Tower. As air is introduced into the tower, a fraction of this water is evaporated, cooling the remaining water.
Closed Circuit Cooling Towers
Closed Circuit Cooling Towers keep the process fluid clean and contaminant free in a closed loop. This creates two separate fluid circuits:
- An external circuit, in which spray water circulates over the coil and mines with the outside air.
- An internal circuit, in which the process fluid to be cooled circulates inside the coil.
During operation, heat is transferred from the warm fluid in the coil to the spray water, and then to the atmosphere as a portion of the water evaporates. In addition to chiller application and industrial process cooling, Closed Circuit Cooling Towers are often used in heat pump loops, where closed loop cooling is preferred.
When applied to HVAC and light industrial systems, Evaporate Condensers provide lower condensing temperatures and compressor horsepower serving of up to 15 percent compared with traditional systems. In an evaporative condenser, refrigerant vapor is condensed in a coil, which is continually wetted on the outside by a circulating water system. Air is circulated over the coil, causing a small portion of the circulating water to evaporate. The evaporation removes heat from the vapor in the coil, causing it to condense.