Critical evaluation of R134a, R1234yf and R744 in passenger car cooling systems

The Montreal Protocol on ozone-depleting substances and the Kyoto Protocol to the United Nations Framework Convention on Climate Change are affecting the refrigeration industry. Both documents have banned the use of substances responsible for ozone depletion and global warming. The automotive industry must keep up with these changes. The design of cooling systems in cars must meet the requirements of new refrigerants. In addition, changing the production profile of large car companies towards electric and hybrid cars increases this need. This development has a significant impact on the solutions installed in passenger vehicles. The paper presents a critical assessment of R134a, R1234yf, and R744 in passenger car heat pump systems. The possibility of their use in common air conditioning systems with motor drive and in the heat pump of an electric vehicle was presented. The calculation algorithm of the heat pump system has been developed, showing the influence of the physical properties of refrigerants on efficiency during the process of the designed heat pump system. The impact of using new refrigerants in the car production process has been analyzed and commented on. The influence of thermodynamic and ecological properties of refrigerants on the process of designing a heat pump system using a calculation model was described. Types of heat pump in electric cars and a calculation model were presented.