HFO, Retrofit, Flooded Evaporator
The selection criteria of working fluids for industrial refrigeration, dictated by both safety and environmental factors, has evolved continuously since the advent of refrigerant technology. With each advancement in working fluid class, considerations are made around the compatibility with regards to retrofitting existing equipment. This is still the case for the transition to HFO blends. The combination of the R-22 phase out with a large majority of well-maintained R22 ice rink chillers currently in operation creates a need for a retrofit gas that will meet or exceed existing performance criteria while complying with current regulatory requirements. However, it has long been assumed that when dealing with flooded evaporators, such as the case with many ice rink chillers, the predicted decrease in performance of zeotropic retrofit refrigerant blends compared to their incumbents is prohibitive. In the absence of a single component or azeotropic refrigerant retrofit option that matches R-22 energy performance, has an ozone depletion potential of zero, and has a low global warming potential, zeotropic blends must be evaluated. This paper discusses the retrofit from R-22 to R-449A of an indirect ice rink refrigeration machine, also referred to as an ice plant, with a flooded evaporator. Ice plant power measurements were combined with evaporator heat loads to compare relative system efficiencies. A chiller model was employed to demonstrate estimated annual energy consumption between R-22 and R-449A based on the collected run data. Finally, refrigerant samples one-month and one-year post retrofit were used to visualize the refrigerant blend composition shift throughout the system.