The analysis of bus refrigeration system working with R134a and R744 refrigerants according to different parameters in case of using two-phase ejector as expansion valve

Nearly in all of today's buses and midibuses, air-conditioning systems are available. Compressor of the air-conditioning system is driven by pulley connected to the engine shaft. Due to the extra load on the engine, fuel consumption is increased. As a result of increasing COP, it's possible to use smaller size of air conditioner elements and decrease of fuel consumption. COP of the air conditioning system can be increased by using two phase ejector. So expansion loses in expension valve can be recovered and this yields decrease of compressor work, thus COP would be increased. In scope of this study, firstly, two-phase ejector refrigeration cycle operating with R134a is analyzed for the bus air conditioning with different parameters. In addition to this, increasing concers about global warming and it's known that artificial refrigerants causes to this, natural refrigerants like R744 (CO2), started to replace artificial refrigerants. So two-phase ejector refrigeration cycle operating with R744 is also analyzed for the bus air conditioning system.