A refrigeration system configured to receive a refrigerant is provided, as well as a walk-in refrigeration unit configured to utilize said system. The refrigeration system comprises: a power source, a condenser unit, an evaporation unit, a plurality of compressors, wherein each of the plurality of compressors is communicably coupled to the condenser unit, and a plurality of expansion devices, wherein each of the plurality of expansion devices is communicably coupled to the evaporation unit. The system is configured to receive an A3 refrigerant having a Global Warming Potential (GWP) value less than 10.