Comparison of the new refrigerant R1336mzz(E) with R1234ze(E) as an alternative to R134a for use in heat pumpsDrofenik, Jan (Avtor) Urbancl, Danijela (Avtor) Goričanec, Darko (Avtor) heat pumpinternal heat exchangerHFOHFC alternativeGWPR134a is currently the most widely used refrigerant, whose problem is the high value of the global warming potential, and which will have to be replaced in the near future. Thus far, R1234ze(E) has proven to be the most suitable alternative, but it is slightly flammable. Recently, R1336mzz(E) has emerged as a possible alternative. During the research, the mentioned refrigerants were compared with simulations using the Aspen Plus software package in the case of using groundwater as a heat source. It was found that R1336mzz(E) could be a suitable alternative to R134a since the highest value of coefficient of performance was obtained using it. However, it must be superheated with an internal heat exchanger. The problem with using an internal heat exchanger is that the superheating of the refrigerant vapors affects the isentropic efficiency of the heat pump compressor negatively and, consequently, lowers the COP value of the heat pump. It has been shown that a one percent decrease in isentropic efficiency results in a one percent decrease in the COP value.MDPI AG20222025-05-15 07:27:00Članek v reviji92815UDK: 620.92/.98COBISS_ID: 94960899DOI: 10.3390/pr10020218ISSN pri članku: 2227-9717sl© 2022 by the authors