As production of CFCs refrigerants is reduced and ultimately eliminated, environmentally acceptable replacement compounds are needed for use in chillers. These alternative refrigerants should have operating characteristics similar to those of CFCs, both to reduce the cost of converting existing chillers to alternatives and to limit the design changes involved in manufacturing new chillers that can use the alternative refrigerants. R123 or HCFC-123 is a replacement for R11 in chillers and is providing this new refrigerant to chiller manufacturers for use in new and existing chillers. (1) PRODUCTION CEASES IN 2020