A heat pump is a machine or device that moves heat from one location to another location mechanically. Refrigerant within a heat pump is used as the working fluid. Different standard refrigerants (such as chlorofluorocarbons, hydro-fluorocarbon isobutene …) are cycled throughout the heat pump’s system. When replacing the standard refrigerant (1,1,1,2-tetrafluoroethane; R-134a) within the heat pump with formaldehyde under the same compressor power, the efficiency should increase.
University of Maribor explained about the use of Formaldehyde as a refrigerant in Heat pumps, In his recently published article with renewable energy he compare the use of different refrigerant in heat pump and the effect of formeldehyde to use as a refrigerant.