R-1234ze(Z) (cis-1,3,3,3-tetrafluoroprop-1-ene; CF3CH=CHF)has no ODP and almost certainly has a GWP on the order of probably no more than 10 or so based on values of other ﬂuorinated propene isomers. Its boiling point is 9.58℃. What is unknown (no data has been published in the open literature) is its toxicity or ﬂammability.
One research team from University of Padova and the Catholic University of America has done the experimental assessment of HFO-1234ze(Z) for high temperature heat pumps. It investigates HFO-1234ze(Z) condensation inside a BPHE. HFO-1234ze(Z) shows heat transfer coefficients much higher than those of all the refrigerants now used in heat pumps such as HFC-236fa, HFC-134a, HC-600a, HFO-1234ze(E). HFO-1234ze(Z) is a very promising low GWP refrigerant for high temperature heat pumps.
Keishi Kariya’s research team conducted the HFO1234ze(Z)’s thermal conductivity and viscosity measurement at a temperature from 290 to 440 K and at a pressure from 0.5 to 3 MPa in order to develop heat pump system supplying high-level heat source or ORC cycle for low-temperature level waste heats.