As autumn gracefully bows out, the approach of winter heralds a unique set of challenges for those responsible for operating and maintaining HVAC cooling towers. Because, while the frosty winter air may bring about a period of free cooling for cooling tower operators, it also opens the door to a less favorable guest – ice buildup.
Ice accumulation is something tower operators should try to avoid, as ice can cause failure to a tower’s fill, its louvers and even the structure itself. Luckily, HVAC cooling towers have been operated in some of the coldest environs in the world by following the relatively simple protocols listed below.
1. Maintain a Consistent Heat Load
Water circulation must continue to bear a heat load. Without this, water within the tower can chill to the air’s wet-bulb temperature, forming troublesome ice. Excessive ice obstructs airflow, adds weight, and poses a threat to your tower’s fill.
2. Sustain Minimum Water Flow Rate
Your tower’s minimum water flow rate should be upheld, if not exceeded, to guarantee uniform water distribution across the media. For cold weather operation, consider Marley’s Variflow nozzles and cups, an excellent addition to existing towers that modify low flow conditions.
3. Match Cells to Flow
In situations where the system’s condenser water flow is reduced below the minimum, an equivalent number of cells should be diminished, ensuring that the flow surpasses the minimum per cell.
4. Implement Bypass for Low Heat Load
When the heat load drops perilously low, a bypass for the operating water flow directly to the cold-water basin is crucial. This intelligent move prevents overcooling and freezing within the fill media.
5. Control Airflow
Manage airflow meticulously to maintain above-freezing water temperatures within all sections of the fill across all operational cooling tower cells. While fan cycling or two-speed motors are options, a variable frequency drive is recommended for eliminating temperature gradients and ensuring smooth setpoint tracking. Sequential fan cycling can lead to significantly lower temperatures in cells where fans are off, raising the risk of freezing.
6. Harness Basin Heaters
During cold weather operations, basin heater systems are your allies in averting freezing at the basin outlets during reduced heat load periods or prolonged shutdowns. Marley offers various basin heater options, from basic relay-based control to advanced, reconfigurable setpoint control compatible with waterside economizing.
These eight principles form the cornerstone of winter operation success and ensure your cooling tower remains immune to the icy grasp of the cold season.
Do you need cooling tower parts, service, or inspections? Are you considering refurbishing your cooling system, replacing it all together or want to talk to someone about advancements in cooling technology, system efficiency and current industry standards? Or, maybe you’re looking additional in-depth insight on winter operations and effective freeze protection for your cooling towers?
If so, give us a call at 908-541-1010 or click on the (contact us) link at the bottom of the page. Our sales engineers are ready to answer your questions and discuss your needs.