Calcium Chloride versus Glycol
On an indirect refrigeration system a choice must be made between the type of secondary coolant that you select. Both Calcium Chloride and glycol have been successfully used over the years and there are applications where both secondary coolants have an advantage. To a much lesser degree other heat transfer mediums such as methyl alcohol have also been utilized in the ice rink industry.
In regards to energy efficiency, Calcium Chloride is the better choice. Its heat transfer coefficient is much better than glycol. This fact equates to smaller, less expensive chillers for the same heat transfer. The heat transfer in the floor piping system is also better. Due to the superior heat transfer characteristics, the brine pump can be smaller and the required pump horsepower and corresponding energy consumption is reduced with calcium chloride.
Calcium chloride is highly corrosive when not maintained properly. With proper system design and operation it is still the best choice for most ice rink applications. The system components must be selected specifically for the Calcium Chloride. Typically chillers are made out of carbon steel or cuper-nickle. Brine pump shafts and butterfly valve stems should be made out of stainless steel.
With a system utilizing Calcium Chloride, it is imperative that the system is kept full at all times and no air is allowed to come in contact with the internal components. A high-grade environmentally friendly rust inhibitor must be used to ensure equipment longevity. It is good practice to carry out routine in house brine tests to monitor brine strength and pH on a semi annual basis and to request a lab report once a year.
In systems that are occasionally emptied and filled such as a portable system, glycol can be a very good choice. Glycol will reduce the effects of corrosion in systems that are occasionally opened to the air. It is still important to use good quality inhibited glycol such as Dow SR-1 and to ensure that annual lab samples are taken to verify the integrity of the solution.