Closed-loop, water-based heat transfer systems exposed to freezing temperatures are vulnerable to damage if the formation of ice causes system pressure to exceed the yield strength (burst pressure) of the equipment.
Solutions of glycol-based fluids provide two different kinds of cold weather protection:
- Burst Protection: If your system does not operate during the winter and cold weather start-up will not be required, you will want to specify a glycol concentration sufficient to prevent bursting but not necessarily high enough to maintain the fluid in a pumpable state. Solutions of all seven Dow inhibited glycol-based fluids can provide burst protection to below -73°C (-100°F).
- Freeze Protection: If your system must remain operational in cold weather, or if cold weather start-ups may be required, freeze protection will be needed. As indicated by their minimum recommended operating temperatures, the freeze protection capabilities of DOWTHERM™, DOWFROST™, and DOWCAL™ fluids vary slightly. Choose a solution concentration that will prevent the formation of ice crystals at 3°C (5°F) below the lowest anticipated system temperature.