<p>According to EU regulations, restrictions on the use of refrigerants with high<br />greenhouse effect was begun to seek alternative refrigerants. A comparative energy<br />and exergy analysis of R124zd (E) fluid heat pump systems with low greenhouse effect<br />instead of R134A fluid was done. The EES program was used in the analysis. Instead<br />of conventional heat pump systems, parallel heat pump system and heat exchanger<br />heat pump system were used. During the analysis, different evaporator temperatures,<br />condenser temperatures, superheating temperatures, and changes in compressor<br />efficiencies over the heating power coefficient were investigated. When two systems<br />were compared, it is seen that the parallel connected compressor heat pump system is<br />more efficient than the heat exchanger heat pump system. When comparing fluids, it is<br />concluded that the R1233zd (E) fluid was an alternative to the R134A fluid. The results<br />were shown in graphical form. As a result, it is aimed to be a current work on the use of<br />alternative fluids to be used in industrial applications and in the future .</p>