Second law analysis of an automotive air conditioning system using HFO-1234yf, an environmentally friendly refrigerant

Performance Characteristics of Automobile Air Conditioning Using the R134a/R1234yf Mixture

“…As the ratio of R1234yf in the R134a/R1234yf system increased, the total exergy destruction rate decreased by 25.8% on average at all outdoor temperatures. Our results were compared with those of Golzari et al [ 24 ], who performed an exergy analysis of R134a and R1234yf systems when the inlet air temperature at the condenser was changed from 25 °C to 45 °C under the constant inlet air temperature of the evaporator (27 °C). They reported that the total exergy destruction rate of the R134a and R1234yf systems increased by 3.1% and 2.9%, respectively, when the outdoor air temperature increased from 32.5 °C to 37.5 °C and that the total exergy destruction rate of the R1234yf system was reduced by 37.5% on average, compared to that of the R134a system.…”

“…They reported that the COP of the CO 2 /propane mixture system with a CO 2 mass fraction of 60% was 29.4% higher than that of the CO 2 system and similar to that of an R134a system, at the same compressor speed. Golzari et al [ 24 ] analyzed the exergy efficiency to investigate the potential of R1234yf as an alternative to R134a in automotive air-conditioning systems. They found that the use of R1234yf increased exergy efficiency, compared to the R134a system, and maximum entropy generation and exergy destruction occurred in the compressor.…”

Energy, Exergy and Economic Evaluation Comparison of Small-Scale Single and Dual Pressure Organic Rankine Cycles Integrated with Low-Grade Heat Sources

“…In the case of the pump, the size is defined in terms of the power consumed, which is determined by means of Equation (6).Ẇ pump =ṁ pump (h out − h in ) (6) whereẆ pump is the pump power,ṁ turb is the mass flow rate across the pump, h in and h out are the enthalpies at the pump inlet and outlet, respectivelty.…”

“…Some of these new thermodynamic cycles employ pure and zeotropic mixtures of organic fluids due to their low boiling temperatures, which results in an efficient utilization of the heat source [3][4][5]. In addition, new environmental friendly and low Global Warming Potential (GWP) fluids and nanofluids have been studied and tested to improve resources utilization [6,7]. The Organic Rankine Cycle (ORC) has emerged as an alternative technology to produce power from non-conventional energy sources, e.g., waste heat, solar radiation, geothermal heat and biomass.…”

Exergetic Investigation of a R1234yf Automotive Air Conditioning System with Internal Heat Exchanger

“…Additionally, they found that the second law efficiency of the system with R1234ze and R134a is higher than that of R1234yf. Golzari et al [21] developed a simulation model to determine the steady-state performance of an AAC system that uses R1234yf as an alternative to R134a by applying the second law of thermodynamics. As a result of their simulation, the highest exergy destruction occurred in the compressor and the exergy efficiency of the system is higher for the R1234yf in comparison with R134a.…”