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SECONDARY REFRIGERANT O P T I O N S General The secondary refrigerant is the fluid that is circulated throughout the rink floar in an indirect refrigeration system. The fluid removes the heat from the floar and transfers it to primary refrigerant (ammonia) stored in the ice mechanical room. The oval's refrigeration system uses 26% calcium chlaride a�ld water solution. The RSVC Arena does not use a secondary refrigerant because it uses a direct refrigeration system. However, switching the RSVS Arena from a direct system to an indirect system will be one option to consider in the near future as discussed in this report. Options There are two main secondary refi-igerants that are used far ice arena applications, calcium chlaride (often referred to as "brine") and ethylene glycol. In some cases, although fairly rare, propyiena glycol is used. A brief description of each fluid is given below in arder of the highest efficiency to the lowest efficiency. The efficiency of the secondary refrigerant is determined by a number of factars including thermal conductivity, specific heat, fluid flow characteristics, surface area, etc. The use of a calcium chlaride solution leads to an overall system e�ciency of 8% to 12% �'eater than when ethylene glycol is used. Calcium Chloride. This is a salt and water mixture. The chemical properties of the calcium chlaride solution allow it to be pumped easier and to transfer heat at a higher rate than glycol. Therefare the refrigeration equipn�ent can be reduced in size. This leads to an overall system efficiency of 8% of 12% greater than glycol. There is approximately 22,000 gallons o f calcium chlaride solution in the existing system. The disadvantage of using calcium chlaride as a secondary refrigerant in this application is that it can turn corrosive when exposed to air. System using calcium chlaride requires mare monitaring and maintenance. Once mixed with ammonia refrigerant, as has been experienced at the oval, it becomes even more corrosive and potentially a hazardous chemical. The approximate cost per gallon at 24% concentration (suppliers no longer manufacturer a 26% solution), in bulk quantity is $0.89 per gallon. The low materials cost and higher over system efficiency make calcium chlaride attractive in ice rink applications to lower up front capital costs and long ter�n operating costs. EthyleneGlycol. This is often referred to as "antifreeze" and is similar to what is used in the radiatar of automobiles. The main advantage of ethylene glycol is that it is not corrosive and therefare requires less monitaring and maintenance. One disadvantage in using ethylene glycol besides the reduced system efficiency is the potential contamination that can occur ifthe system leaks. Ethylene glycol will remain in high concentrations in the ground far long periods of time. The approximate cost per gallon at 40% strength, in bulk quantity is $4.22 per gallon. Propylene Glycol. This is a food based glycol that is much mare environmental friendly than ethylene glycol. Propylene glycol is not used very often in ice arena applications inainly because of its lower e�ciency. The cost per gallon will be higher than ethylene glycol. �