Automobile Air Conditioning Research Articles

Research on thermal comfort of human body under localized automotive air conditioning

Abstract In this study, we design localized automotive air conditioning to balance the contradiction between the thermal comfort of the driver in the cockpit and the energy saving and environmental protection of an automobile's air conditioner. The simplified model of a certain car cockpit is selected as the research object. Three types of air outlet structures of localized automotive air conditioning are designed, and numerical simulation is performed to study flow field distribution and human thermal comfort in the cockpit under different air outlet combinations of localized automotive air conditioning. The final evaluation result indicates that the thermal comfort of the driver is good under localized automotive air conditioning. Moreover, the energy-saving effect of localized automotive air conditioning is remarkable and its cooling rate is faster. Localized automotive air conditioning achieves about 41.4% more energy saving than ordinary automotive air conditioning.

Experimental study on the impact of indoor unit airflow velocity on the performance of an automotive heat pump system with a suction line heat exchanger

This study aimed to investigate the effect of changing the indoor unit air flow rate on the performance of an automobile heat pump with a suction line heat exchanger. Using a four-way valve, the automotive heat pump system was developed by reversing the refrigerant direction in the automobile air conditioning system, excluding the compressor. A suction line heat exchanger was added to the test system to enhance heat transfer between the liquid and suction lines of the automotive heat pump system. Performance comparisons were first performed for R134a and R1234yf by disabling the suction line heat exchanger. Then, the suction line heat exchanger was activated for R1234yf, and the tests were repeated. Performance comparisons were made for two different compressor speeds and three different indoor unit airflow speeds. It was found that using the heat exchanger in R1234yf operations improved the heating capacity, compressor discharge temperature and coefficient of performance by approximately 1.8 %, 5.1 % and 5.9 %, respectively. The heating capacity of the heat pump system using R134a, R1234yf, and R1234yf with the suction line heat exchanger was determined to be in the range of 2.46–3.29 kW, 2.35–3.04 kW, and 2.39–3.11 kW, respectively. An increase in the airflow speed of the indoor unit from 1.4 m s−1 to 3.2 m s−1 resulted in an average decrease of approximately 12.3 % in the compressor discharge temperature. In contrast, the heating capacity and coefficient of performance increased by approximately 11.8 % and 14.4 % on average, respectively, for R1234yf operations with the heat exchanger. This study revealed that by optimizing the air flow rate in the R1234yf heat pump system with a suction line heat exchanger, improvements in the heating capacity and coefficient of performance can be achieved, thus providing better thermal comfort in the passenger compartment.

Investigation of Wall Boiling Closure, Momentum Closure and Population Balance Models for Refrigerant Gas–Liquid Subcooled Boiling Flow in a Vertical Pipe Using a Two-Fluid Eulerian CFD Model

The precise design of heat exchangers in automobile air conditioning systems for more sustainable electric vehicles requires an enhanced assessment of CFD mechanistic models for the subcooled boiling flow of pure eco-friendly refrigerant. Computational Multiphase Flow Dynamics (CMFDs) relies on two-phase closure models to accurately depict the complex physical phenomena involved in flow boiling. This paper thoroughly examines two-phase CMFD flow boiling, incorporating sensitivity analyses of critical parameters such as boiling closures, momentum closures, and population balance models. Three datasets from the DEBORA experiment, involving vertical pipes with subcooled boiling flow of refrigerant at three different pressures and varying levels of inlet liquid subcooling, are used for comparison with CFD simulations. This study integrates nucleate site density and bubble departure diameter models to enhance wall boiling model accuracy. It aims to investigate various interfacial forces and examines the S-Gamma and Adaptive Multiple Size-Group (A-MuSiG) size distribution methods for their roles in bubble break up and coalescence. These proposed approaches demonstrate their efficacy, contributing to a deeper understanding of flow boiling phenomena and the development of more accurate models. This investigation offers valuable insights into selecting the most appropriate sub-closure models for both boiling closure and momentum closure in simulating boiling flows.

Refrigerant Selection in Air Conditioning Systems Considering Thermodynamic, Environmental, and Economic Performance Using the BHARAT-II Multi-Attribute Decision-Making Method

A simple and effective multi-attribute decision-making method, named as "Best Holistic Adaptable Ranking of Attributes Technique (BHARAT)-II”, to choose the best refrigerant for air conditioning systems is presented. The thermodynamic properties of the refrigerants, and their environmental, and economic performances are also considered for the selection. Two case studies are provided to demonstrate the proposed multi-attribute decision-making method. The first case study addresses the problem of selecting the best refrigerant for residential split air conditioners out of 15 alternative refrigerants considering 12 selection attributes; the second case study addresses the problem of selecting the best refrigerant for automobile air conditioning systems by considering 14 alternative refrigerants and 13 selection attributes. The results of the proposed decision-making method are compared with those of other well-known multi-attribute decision-making methods such as EDAS, TOPSIS, and MOORA. The proposed method is shown to be simple to implement, providing a logical way for allocating weights to the selection attributes and is useful to solve the best alternative refrigerant selection problems of the residential as well as industrial refrigeration and air conditioning.

Occupant-centric cabin thermal sensation assessment system based on low-cost thermal imaging

Assessing cabin occupants' thermal sensation in real-time enables automatic control of car air conditioning, improving driving safety and energy efficiency. Traditional methods, limited by their need for numerous physiological parameters, have restricted practicality. For this purpose, this study employs a low-cost thermal imaging sensor as the hardware core to establish a cost-effective and non-contact real-time assessment system for the thermal comfort of occupants within a cabin. The system comprises a thermal sensation assessment model developed based on subject experiments, along with facial recognition and segmentation algorithms optimized for thermal images. The thermal sensation assessment model developed, which employs cheek temperature, solar radiation intensity, and cabin air temperature as its features, exhibited an R2 of 0.617 on the test set. Furthermore, the facial recognition algorithm established for thermographic imaging achieved a mean accuracy of 96.5% and a recall rate of 99.0%. The system underwent validation in real-world vehicle environments, proving its ability to accurately detect and measure the cheek temperatures of occupants in the cabin and execute thermal sensation assessments. With a mean absolute error of 0.5 thermal sensation units in its output, its accuracy in practical applications was affirmed. This research provides an effective solution for automatically adjusting cabin air conditioning.

Enterovirga aerilata sp. nov. and Knoellia koreensis sp. nov., isolated from an automobile air conditioning system.

Two strictly aerobic and rod-shaped bacteria, labelled as DB1703T and DB2414ST, were obtained from an automobile air conditioning system. Strain DB1703T was Gram-stain-negative, while strain DB2414ST was Gram-stain-positive. Both strains were catalase-positive and oxidase-negative. Strains DB1703T and DB2414ST were able to grow at 18-42 °C. Strain DB1703T grew within a NaCl range of 0-3 % and a pH range of 6.0-8.0; while strain DB2414ST grew at 0-1 % and pH 6.5-8.5. The phylogenetic and 16S rRNA gene sequence analysis indicated that strains DB1703T and DB2414ST belonged to the genera Enterovirga and Knoellia, respectively. Strain DB1703T showed the closest phylogenetic similarity to Enterovirga rhinocerotis YIM 100770T (94.8 %), whereas strain DB2414ST was most closely related to Knoellia remsis ATCC BAA-1496T (97.7 %). The genome sizes of strains DB1703T and DB2414ST were 4 652 148 and 4 282 418 bp, respectively, with DNA G+C contents of 68.8 and 70.5 mol%, respectively. Chemotaxonomic data showed Q-10 as the sole ubiquinone in DB1703T and ML-8 (H4) in DB2414ST. The predominant cellular fatty acid in DB1703T was summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c), whereas iso-C16 : 0, C17 : 1 ω8c, and iso-C15 : 0 were dominant in DB2414ST. Overall, the polyphasic taxonomic comparisons showed that strains DB1703T and DB2414ST were distinct from their closest taxa and represent novel species within the genera Enterovirga and Knoellia, respectively. Accordingly, we propose the names Enterovirga aerilata sp. nov., with the type strain DB1703T (=KCTC 72724T=NBRC 114759T), and Knoellia koreensis sp. nov., with the type strain DB2414ST (=KCTC 49355T=NBRC 114620T).

The abundance and pathogenicity of microbes in automobile air conditioning filters across the typical cities of China and Europe

Bioaerosols are widely distributed in urban air and can be transmitted across the atmosphere, biosphere, and anthroposphere, resulting in infectious diseases. Automobile air conditioning (AAC) filters can trap airborne microbes. In this study, AAC filters were used to investigate the abundance and pathogenicity of airborne microorganisms in typical Chinese and European cities. Culturable bacteria and fungi concentrations were determined using microbial culturing. High-throughput sequencing was employed to analyze microbial community structures. The levels of culturable bioaerosols in Chinese and European cities exhibited disparities (Analysis of Variance, P < 0.01). The most dominant pathogenic bacteria and fungi were similar in Chinese (Mycobacterium: 18.2–18.9 %; Cladosporium: 23.0–30.2 %) and European cities (Mycobacterium: 15.4–37.7 %; Cladosporium: 18.1–29.3 %). Bartonella, Bordetella, Alternaria, and Aspergillus were also widely identified. BugBase analysis showed that microbiomes in China exhibited higher abundances of mobile genetic elements (MGEs) and biofilm formation capacity than those in Europe, indicating higher health risks. Through co-occurrence network analysis, heavy metals such as zinc were found to correlate with microorganism abundance; most bacteria were inversely associated, while fungi exhibited greater tolerance, indicating that heavy metals affect the growth and reproduction of bioaerosol microorganisms. This study elucidates the influence of social and environmental factors on shaping microbial community structures, offering practical insights for preventing and controlling regional bioaerosol pollution.

Transitioning to low GWP refrigerants in automobiles: A numerical simulation study on R1234yf/R152a’s heat transfer characteristics in porous microchannels

Automobile air conditioning systems significantly contribute to vehicle energy consumption. The transition to new, environmentally sustainable refrigerants in place of traditional ones is a critical trend shaping the future of this industry. The prevalent refrigerant R134a, used in automotive air conditioning, is environmentally detrimental, necessitating the development of low Global Warming Potential refrigerants as viable long-term alternatives. This study examines the flow heat transfer characteristics of the proposed refrigerant blend R1234yf/R152a in porous microchannel tubes via numerical simulation. It assesses the impact of heat flux, mass flow rate, saturation temperature, and wall superheat on the Jakob number, vaporization core density, and boiling heat transfer coefficient. Furthermore, it compares these parameters with those of R134a and R1234yf to evaluate the potential of R1234yf/R152a as a substitute. The findings indicate that the Jakob number differences among the three refrigerants are negligible. Notably, R1234yf/R152a consistently exhibits higher vaporization core density and the highest boiling heat transfer coefficient, coupled with the lowest pressure drop, thereby affirming its suitability as a heat transfer-efficient alternative. These insights could inform the enhancement and gradual transition from R134a in automotive air conditioning systems.

Investigation of an automobile air-conditioner with a liquid-suction heat exchanger using R134a and R1234yf

Air-conditioning systems (ACs) are essential in hot and humid climates to ensure acceptable ambient air quality as well as thermal comfort for buildings users. It is essential to improve refrigeration system performance without increasing the effects of global warming potential (GWP) and ozone depletion potential (ODP). The main objective of this study is to evaluate the performance of an air conditioning system that operates with a liquid suction heat exchanger (LSHX) through implementing refrigerants with zero OPD and low GWP (i.e., R134a and R1234yf). Liquid suction heat exchanger (LSHX) was added to an automobile air conditioning system (AACS).When Liquid suction heat exchanger was added to the cycle, primary results indicated that an enhancement in the cycle coefficient performance (COP) by 25.2 %and 17.3% for R134a and R1234yf respectively, and decreasing in mass flow rate of the refrigerants used (m ̇_r). Also increasing in refrigeration effect (RE) by 4.2% and 2.3% for R134a and R1234yf respectively. Presence of LSHX caused increasing in heat rejected by condenser (Qcond.) according to increasing in sub-cooling degree and decreasing in compressor work (Wcomp.), increasing in condenser exergy destruction (X. des. cond.) and thermostatic expansion device (TXV) exergy destruction, but decreasing in compressor and evaporator. Summary of previous experimental and numerical studies is presented as well.

Theoretical comparison analysis of R134a, R1234yf, R452A and R454C refrigerants used in automobile, trailer and commercial and industrial cooling systems

The increasing environmental disasters in recent years are caused by the release of artificial substances into the environment. The majority of artificial-containing emissions originate from petrochemical products. It also contributes to artificially containing refrigerants used in cooling systems. Artificial refrigerants have contributed greatly to the depletion of the ozone layer and subsequently to global warming. Research on new refrigerants as an alternative to refrigerants that contribute to every environmental disaster is of great importance. In this study, theoretical performance comparisons were made between R1234yf, which is an alternative to R134a refrigerant used in automobile air conditioning systems, and R452A, R454C refrigerants, which are used as alternative refrigerants in industrial, commercial and trailer cooling systems. Performance analyses were carried out according to different condenser and evaporator temperatures. Analysis results are given depending on condenser/evaporator pressure ratio, mass flow rate, compressor power, cooling effect coefficient (COP) and compressor outlet temperature. According to the study results, it was observed that the COP value increased with the increase in evaporator temperature, while the compressor inlet-outlet pressure ratio, refrigerant flow rate, compressor power and refrigerant compressor outlet temperature decreased. It was observed that the refrigerant with the highest compressor power and mass flow rate was R452A, followed by R1234yf, R454C and R134a, respectively. R134a was found to have an average of approximately 5.4%, 8.6% and 0.6% higher COP than R1234yf, R452A and R454C, respectively.

Wearable active-cooling garment for personalized thermoregulation in vehicle

The issue of energy waste caused by automobile air conditioning while improving the thermal environment of the compartment necessitates immediate attention. In this study, a liquid cooling garment (LCG) for vehicles was designed based on the heat flow field in the compartment. The silicone tubes (with inner diameter of 0.5 mm and a total length of 71.5 m, respectively) are woven into a T-shirt and used as heat exchange pipelines in eleven regions (including the chest and belly). We adopted the thermoelectric cooler with a maximum refrigeration coefficient of 0.68 for the active cooling supply, and the maximum energy consumption of the LCG system is 0.15 kW∙h. The temperature distribution of an outdoor parking compartment was monitored in the summer to verify the simulation results. The experiment results have shown that the maximum temperature difference between the subject wearing LCG and the reference group was 3 °C under the high-temperature environment (37–42 °C). The thermal sensation score of the subject ranged from −1 to 3, and the thermal comfort and thermal acceptability scores ranged from −0.01 to 1. The LCG has been demonstrated to meet human cooling needs. This work provides a new idea for designing personal temperature control systems and establishes a foundation for the wide application of cooling garments.

Z-Freq Hybrid: Signal Analysis Based Car Air Conditioning Compressor Monitoring Technique Using Accelerometer and Piezo-Film Sensor

The efficiency and performance of car air conditioning systems rely heavily on adequately functioning the compressor and its associated components. There are many ways to detect an unfunctioning compressor and one of them is through vibration. Disfunctioning compressors could lead to discomfort, fatigue, stress and fogging windows, especially in long-distance driving. Thus, researchers focus on detecting the nonfunctioning car air conditioning compressor early. This paper introduced a new enhanced statistical method, namely Z-freq Hybrid. Z-freq Hybrid was based on a Z-notch frequency domain filter with a combination input of two different types of sensors introduced to detect functioning compressors. Data were recorded at various compressor speeds using an accelerometer and piezo film sensor with Signal Express 2015 software. The acceleration (m/s2) and voltage (mV) data were analyzed to find the combination degree of scattering data in a Z-freq Hybrid chart. The analyzed data show that the Z-freq Hybrid coefficient increases as the compressor’s speed increases. Then, the value dropped significantly when the compressor was dysfunctional. In conclusion, a Z-freq Hybrid can be employed to detect abnormalities and irregular vibration patterns, which may indicate the impending failure of a compressor.

Energy, exergy and entropy analysis with R1234yf as an alternate refrigerant to R134a of automobile air conditioning system

A major portion of the worldwide emissions arise from mobile air-conditioning systems with hydrofluorocarbon refrigerant as working substance and which is one of major cause for the greenhouse effect. R134a refrigerant having GWP of 1400 has been extensively used in car air conditioning. To reduce greenhouse gas emissions, the current R134a refrigerant must be phase out as per Kigali Amendment. The present study deals with cooling load calculation of car model by heat balance method as per ASHRAE standard using local climate condition. Further, thermodynamic analysis of R1234yf as an alternate refrigerant to R134a has been carried out for automobile air conditioning system. The required properties of refrigerants are extracted from Engineering Equation Software. The thermodynamic analysis is carried out to study the effect of operating parameters viz. condensing temperature, evaporating tempera-ture, degree of superheating and degree of subcooling on COP, EDR, exergy efficiency and entropy generation. The previous literature reports mainly focus on separate study of either cooling load calculation or energy analysis or exergy analysis of R1234yf and R134a for au-tomobile air conditioning system, while this paper presents the comprehensive study of new low GWP R1234yf as an alternate refrigerant to R134a in automobile air conditioning system with cooling load calculation including the concept of energy, entropy and exergy analysis. The percentage difference in COP between R134a and R1234yf system varies from 2.44 % to 4.78 % while percentage difference in EDR varies from 6.79 % to 2.87 % when evaporating temperature varied from -10 °C to 10 °C. With 12 °C of superheating at compressor inlet, the COP of R134a is 3.9 whereas COP of R1234yf is 3.75, which makes 3.85 % lower than that of R134a. The R1234yf has 4.78 % lower value of exergy efficiency as compared to that of R134a at evaporating temperature of -10 °C and it is found that maximum exergy destruction takes place in compressor.

CFD Analysis of using Deionized Water in Radiator to Enhance the Efficiency for Sustainable Growth

Conventional liquid coolant used in automotive radiators is often used as an engine coolant. Heating systems in automotive air chambers are commonly used to cool circulating fluids, usually water or an aqueous combination of antifreeze agents such as ethylene glycol (EG). This study examines the benefits and issues of the usage of deionized water in all radiators. Deionized (DI) water has received attention as a possible alternative to chemical coolants generally used in automobile air conditioners. Automotive engineers are addressing the demanding situations of intense freezing by developing special garage systems to optimize engine overall performance and limit environmental impact. Compared to conventional refrigerants, the usage of deionized water has lesser environmental consequences, consisting of decreased corrosion and mineral production, which extends radiator lifestyles and improves cooling efficiency. Moreover, DI-water poses several challenges, which include the capability to freeze and compatibility with some radiator materials. Ultimately, this study investigates using deionized water as a refrigerant while used in radiators inside the inlet water. Additionally, it explores the impact of deionized water on engine performance, durability, heat transfer overall performance, corrosion resistance, and potential overheating, at the same time as additionally addressing environmental problems.

Thermodynamic and carbon emission analysis with low GWP refrigerants in automobile air conditioning system

Thermodynamic and carbon emission analysis with low GWP refrigerants in automobile air conditioning system

Impacts of Using AlO Nano Particle to Compressor Oil on Performance of Automobile Air Conditioning System

Impacts of Using AlO Nano Particle to Compressor Oil on Performance of Automobile Air Conditioning System

Analysis of Vaporizer Effect for Accelerated Heat Dissipation of Car Air Conditioner (AC)- An Experimental Study on Gas-Fueled Cars

It is a concrete effort today in realizing the concept of Low-Cost Green Car (LCGC) through the conversion of oil-fueled cars to the form of fuel gas. In the system (fuel system) gas car there is a vaporizer unit that functions to change the liquid phase to the gas phase while stabilizing it at a working pressure of ± 1.5-2 bar, thus the work of the vaporizer unit requires heat. On the other hand, the car’s AC system will dissipate heat through the condenser, where the performance of the cooling system will be better by accelerating the heat disposal in the condenser. This research aims to build an energy conservation system between the AC and Vaporizer systems using an efficient control valve model with the concept of rotation. With the application of this rotational valve system, it is expected that the control of hot fluid to the vaporizer is faster and faster. The results of data analysis showed enthalpy (h) refrigerant changes before and after the expansion valve/capillary pipe, down at 240 kJ/kg. COP increased slightly with efficiency figures rising by 0.03.

Investigating New Environmentally Friendly Zeotropic Refrigerants as Possible Replacements for Carbon Dioxide (CO2) in Car Air Conditioners

The widespread use of automobiles and the increased duration spent within automobiles equipped with air conditioning systems have prompted various countries to enforce regulations that advocate for eco-friendly cooling substances (refrigerants) characterized by a slight global warming potential (GWP) and the absence of an ozone depletion potential (ODP). The imperative for automobiles to possess air conditioning systems that are both high-performing and eco-conscious has emerged as a means to mitigate their ecological impact, reduce fuel usage, and minimize carbon emissions. Zeotropic refrigerants, with a lower GWP than traditional alternatives, contribute to sustainability in car air conditioning by reducing the environmental impact and enhancing the energy efficiency, aligning with global regulations and fostering innovation in the automotive industry. This shift signifies a commitment to mitigating climate change and adopting environmentally conscious practices. The objective of the present study is to introduce blends of zeotropic refrigerants based on CO2 (R-744), namely R455A (a blend of R-744, R-32, and R-1234yf), R469A (a blend of R-744, R-32, and R-125), and R472A (a blend of R-744, R-32, and R-134a), to enhance the thermodynamic performance of pure CO2 refrigerant. Through the utilization of the Aspen HYSYS V11 software, an investigation is carried out involving thermodynamic energy and exergy analyses, as well as system optimization for an automotive air conditioning (AAC) system utilizing these novel zeotropic refrigerant blends, in comparison with the use of R-744 as the refrigerant. The study delves into the impact of parameters such as average evaporator temperature, condenser/cooler pressure, refrigerant flow rate, and condenser/cooler outlet temperature on AACs’ output parameters and subsequently presents the findings. The outcomes reveal that, under equivalent operational circumstances, the adoption of R455A, R469A, and R472A offers improvements in coefficient of performance (COP) by 35.4%, 18.75%, and 2%, respectively, when compared to R744. This shift is advantageous as it mitigates leakage-related issues stemming from the elevated operational pressure of R744 and eliminates the need for cumbersome equipment. R455A and R469A obtain the greatest COP and exergy efficiency (ηex) values, measuring 4.44 and 4.55, respectively, at the identical operating conditions with optimal condenser/cooler pressures of the examined blends. Furthermore, eco-friendly refrigerants R455A and R472A are recommended for integration into AAC systems in vehicles, as they help combat global warming and protect natural surroundings and leakage issues.

Effect Of AC Compressor Modification on Fuel Consumption in Car

The cooling system is a refrigeration technology that is growing, especially regarding the cooling medium (refrigerant), new vehicles nowadays mostly use air conditioning to condition the air in the vehicle's cabin, but for now, there are still many aspects that have not been given much attention, especially the compressor. Compressor systems in vehicles still rely on the engine as a direct drive resulting in increasingly wasteful fuel consumption and reducing the performance of the vehicle. This study analyzes the results of modifying a conventional compressor into an electric compressor by utilizing a split AC compressor whose supply voltage is obtained from a DC to AC inverter on vehicle fuel consumption and the required electrical energy. Inverter modification is highly recommended in the application of car air conditioners, split AC compressors, and others. The results of this research show that AC compressors using split compressors affect fuel consumption.

Experimental and Numerical Studies on an Automobile Air Conditioning System With the Refrigerants R134a, R1234yf, and R1234ze(E)

Abstract The Montreal Protocol of 1987 has put the chlorofluorocarbons (CFCs) into the category of ozone-depleting substances. The hydrofluorocarbons (HFCs), synthesized as alternatives to CFCs, though possess zero ozone-depleting potential, have high global warming potential (GWP). Despite this, numerous applications currently employ HFCs for refrigeration and air conditioning. The 2016 Kigali amendment to the Montreal Protocol suggested a phase out of the HFCs, and this process will go on until 2036 in developed nations and until 2047 in developing nations to accomplish a condition of 85% decrease in the use of HFCs. The refrigerant R134a used in mobile air conditioning has a global warming potential (GWP100) of 1300, which prompted researchers to look for new low GWP refrigerants. Recent research has revealed that the HydroFluoroOlefin (HFO) refrigerants R1234yf and R1234ze(E) with a GWP100 of 4 or less show promise for application in the automobile air conditioning (AAC) field. The AAC requires special attention due to frequent leakages of HFC caused by vibration-induced pipe failures. In this research, the low GWP refrigerants R1234yf and R1234ze(E) are considered to explore the AAC system performance, and comparisons are made with the currently used refrigerant R134a. The numerical simulations are performed by including and excluding liquid-to-suction heat exchanger/internal heat exchanger (IHX). The results show that the use of IHX is advantageous for both R1234yf and R1234ze(E). Even though R134a performed better, R1234yf with IHX is a better low GWP alternative in the current AAC system working with R134a without IHX, with only a slight compromise in the system performance and the performance of R1234yf is better than R1234ze(E). Finally, the numerical simulation results are validated against the experimental results for R134a and R1234yf and found that most of the results agree within 10% deviation for system without IHX and within 15% deviation for system with IHX. Thus, if the AAC systems change to R1234yf with an IHX, the directives set out in the Kigali amendment of 2016 to Montreal Protocol (namely the discontinuation of HFCs for refrigeration) will be satisfied without any significant loss in the performance.