Cooling Equipment Freeze Protection

Winter and cold weather are quickly approaching, even in the mild climate of the Carolinas, we will see below-freezing temperatures and severe winter storms. Are your facility and cooling equipment prepared for this weather?

During my career of almost 50 years, I have seen plenty of freeze-damaged cooling equipment. A large majority of this damage has taken place during the same time each year, which is over the holiday break. Many schools, colleges, and manufacturing facilities are closed and vacant for the time period between the Christmas and New Year holidays. A cold snap or winter storm during this time frame can play havoc on an unattended facility.

Below are a few suggestions:

• Freeze Protect your equipment that is located outdoors or in a non-conditioned space.

  • Prepare in advance for cold weather.

  • The lowest temperatures will occur at night.

  • Your facility is at its greatest freeze risk when it is unoccupied.
    

• Basin heaters are essential to prevent your cooling tower's cold water basins from freezing.

  • If you don’t have basin heaters in your cooling tower cold water basins, have them installed. Make sure to include operating controls with a basin thermostat set at 38 Deg.

  • If you have existing basin heaters, check the operating controls (before cold weather) to make sure they are working properly. Clean any scale or build-up from the basin heater element.
    

• Insulate and heat trace make-up water and process piping.

  • Check the existing heat trace to make sure it is working properly.
    

• Process pumps and other ancillary equipment should be insulated or have insulated houses to protect them.
  

• Use food-grade propylene glycol and /or drain system when possible.
  

• Maintaining flow through heat exchangers and coils can prevent freezing.

  • Install a thermostat to start pumps / open valves when the outside air temperature is below 38 Deg.
    

• With winter storms, come power outages.

  • Make sure your essential freeze protection equipment is on an emergency generator power circuit.
    

• For Air Handling Equipment.

  • Make sure all outside air dampers (intake and exhaust) close tightly when the equipment is off.

  • Check freeze stats to make sure they function properly, stopping the fan when they trip below the set point (38 Deg). For additional protection incorporate a strategy that opens chilled/hot water valves and starts pumps. Make sure exhaust fans that are associated with this equipment shut down as well.

  • Incorporate a night low-limit setpoint function into your building schedule control strategy. During the unoccupied schedule period, start heating equipment when interior temperature reaches night low limit setpoint of (55 Deg adjustable).

  • Make sure large exhaust fans (for production or air conditioning) are off during unoccupied periods.

  • During extremely cold periods consider putting operating equipment in occupied mode during unoccupied times.