The present disclosure relates to a heating ventilation and air conditioning (HVAC) system. The system includes a primary heat transfer loop configured to be disposed at least partially outside of a building, and the primary heat transfer loop includes a heat exchanger, a compressor configured to compress a refrigerant, where the refrigerant is reactive, a condenser configured to receive and condense the refrigerant, and an expansion device configured to reduce a temperature of the refrigerant. The system further includes a secondary heat transfer loop configured to circulate a two-phase fluid at least partially inside the building, wherein the two-phase fluid is less reactive than the refrigerant. The secondary heat transfer loop includes the heat exchanger, where the heat exchanger is configured to transfer energy from the two-phase fluid circulating in the secondary heat transfer loop to the refrigerant, and an evaporator configured to evaporate the two-phase fluid by exchanging energy with an air supply stream flowing across the evaporator.