Cooling Tower Performance Testing

HVAC systems and machinery generate tremendous amounts of heat, which must be continuously dissipated for efficient operation. Although this heat is usually transferred to a cool, flowing volume of water, final rejection is always to the atmosphere and, invariably, is accomplished by some form of heat exchanger. Reducing energy expenditures for a cooling tower may be as simple as regular maintenance and monitoring.

Cooling Tower Operation

In an HVAC process, cooling towers reject heat from the cooling water circulating through the condenser of a chiller. There are two basic types of cooling towers.

Direct or open cooling towers expose the cooling water directly to the atmosphere. The warm cooling water is sprayed over a fill in the cooling tower to increase the contact area, and air is blown through the fill. The majority of heat removed from the cooling water is due to evaporation. The remaining cooled water drops into a collection basin and is re-circulated to the chiller. Indirect or closed cooling towers circulate the cooling water through tubes of a coil bundle in the tower. A separate external circuit sprays water over the cooling tubes to cool the coils through an evaporative process.

Importance of Proper Cooling Tower Maintenance and Monitoring

An improperly maintained cooling tower produces ill effects in a HVAC system. Warmer cooling water will yield condenser temperatures 5 to 10 degrees F higher than a properly maintained cooling tower. This reduces the efficiency of the chiller, therefore wasting energy, increasing operating costs, driving up repairs and shortening the life of Cooling Tower equipment.

A chiller will consume 2.5 to 3.5 percent more energy for each degree of increase in the condenser temperature. For example, if a chiller uses $20,000 of electricity each year, it will cost an additional $500 to $700 per year for every degree increase in condenser temperature. Therefore, for an increase of 5 to 10 degree F, increased energy costs could be expected in the $2,500 to $7,000 range per year.

Pro-MEC Cooling Tower Testing, Monitoring, PM

Pro-MEC Engineering Services, Inc. (Pro-MEC) is fully qualified to evaluate facility cooling tower systems and implement a preventative maintenance and monitoring program.