Experimental assessment of the low GWP refrigerant HFO-1234ze(Z) for high temperature heat pumps

This paper presents the experimental heat transfer coefficients and pressure drop measured during refrigerant HFO-1234ze(Z) saturated vapour condensation inside a commercial Brazed Plate Heat Exchanger (BPHE) and compares this data with similar measurements previously obtained for refrigerant HFC-236fa, HFC-134a, HC-600a, HFO-1234ze(E) in order to experimentally assess refrigerant HFO-1234ze(Z) for high temperature heat pumps. HFO-1234ze(Z) exhibits heat transfer coefficients much higher than those of all the refrigerants now used in heat pumps and frictional pressure drop similar to HC-600a at the same refrigerant mass flux. Therefore, considering also its thermodynamic properties, HFO-1234ze(Z) seems to be a very promising low GWP refrigerant for high temperature heat pumps with a potential capability similar to refrigerant CFC-114 that dominated this type of application before Montreal Protocol.