Rx for maintenance-intensive cooling towers: Think plastic
"We were spending between $5,000 and $10,000 a year on cooling tower repair - patching metal, putting in rubber seals, and gasketing. In other words, ‘band-aid' fixes just to keep the tower from leaking," said Richer. The cooling tower in question was being used on an absorption-chiller to cool two facilities - the Brock Equipment plant and the adjacent Crystal Lake University Center, an educational facility for undergraduate studies and con-tinuing education.
"As the tower got older, not only did we have ongoing leak problems, we started to have a structural problem," added Richer. "The tanks that hold the water on the bottom were getting heavier as we added more materials to fix the leaks. All that weight was beginning to bend the structural members that held the cooling tank together."
When Richer started contemplating replacing the tower, initially he assumed they would install a new tower similar to the existing unit, but then he began investigating an alternative: engineered molded plastic cooling towers that are high-capacity, lightweight, and energy efficient.
Engineered molded plastic cooling towers are one-piece, so there are no problems with seams, welds, and patches that wear prematurely. Richer also noted that plastic towers are rust and corrosion-proof.
REAL ESTATE CONSERVATIONBrock Equipment's cooling tower does not interface with manufacturing processes but supports an absorption chiller that conditions facility air, a demanding application that is clearly affected by tower downtime. For this reason, the reduced maintenance requirements and extended life of molded plastic cooling towers were very appealing to Richer.
He ended up selecting a unit manufactured by Delta Cooling Towers, which produces units that are rotary-cast with a single- or double-wall UV-protected, polyethylene shell that is virtually impervious to weather conditions and harsh environmental elements, and which offer a 15-year warranty.
"If you are familiar with plastics, you know that engineered plastics are very tough. The new cooling tower has been trouble-free. We still have normal maintenance, but there has been no repair work on the tower, no leaks at all," said Richer.
The modular design of engineered plastic cooling towers has also introduced new flexibility in conserving valuable real estate. "With the new Delta system, we actually got more cooling with less tower," Richer said. "Our old 45 ft by 20 ft by 18 ft metal cooling tower was replaced by a lightweight plastic model that is only half that size, yet has slightly greater cooling capacity."
Utility savings can also be realized by reducing the cost of electric power to drive cooling tower fans. In the case of the engineered plastic towers from Delta Cooling, direct-drive motors are employed to power cooling fans, providing energy savings while delivering more horsepower.
"The two motors installed on the old tower were each 40 hp, three-phase, 480V. On the new tower, there are four 10-hp motors," Richer said. "So we now have only half the power requirement. Plus, the new motors are more efficient than the old ones. We have not measured the energy savings, but it's there."