Mobile Air Conditioning System Research Articles

Performance comparison of a mobile air conditioning system using an orifice tube as an expansion device for R1234yf and R134a

The performance merits of a mobile air conditioning (MAC) system with an orifice tube (OT) were experimentally evaluated for R1234yf relative to R134a. The effect of employing a suction/liquid line internal heat exchanger (HEX) was also investigated for R1234yf. To this end, an experimental unit employing the components of an R134a MAC system was set up, equipped with a coaxial internal HEX, and tested at various compressor speeds for both refrigerants. The air temperatures entering the condenser and evaporator were simultaneously maintained at 30, 35, and 40 °C. The R1234yf unit provided on average 22.5% lower and 6.9% higher cooling capacity than the R134a unit for the inactive and active HEX, respectively. Furthermore, the coefficient of performance (COP) for the R1234yf unit without and with HEX was on average 10.9% and 3.5% lower than that for the R134a unit, respectively. The R1234yf unit without and with HEX yielded on average 41.5% and 8.4% lower exergetic efficiency than the R134a unit, respectively. These results revealed that the use of an internal HEX in an R1234yf MAC unit with an OT compensates for the cooling capacity degradation, and the R1234yf unit has almost as high performance as the R134a unit.

A Sensitivity Study of a Bayesian Inversion Model Used to Estimate Emissions of Synthetic Greenhouse Gases at the European Scale

To address and mitigate the environmental impacts of synthetic greenhouse gases it’s crucial to quantify their emissions to the atmosphere on different spatial scales. Atmospheric Inverse modelling is becoming a widely used method to provide observation-based estimates of greenhouse gas emissions with the potential to provide an independent verification tool for national emission inventories. A sensitivity study of the FLEXINVERT+ model for the optimisation of the spatial and temporal emissions of long-lived greenhouse gases at the regional-to-country scale is presented. A test compound HFC-134a, the most widely used refrigerant in mobile air conditioning systems, has been used to evaluate its European emissions in 2011 to be compared with a previous study. Sensitivity tests on driving factors like—observation selection criteria, prior data, background mixing ratios, and station selection—assessed the model’s performance in replicating measurements, reducing uncertainties, and estimating country-specific emissions. Across all experiments, good prior (0.5–0.8) and improved posterior (0.6–0.9) correlations were achieved, emphasizing the reduced sensitivity of the inversion setup to different a priori information and the determining role of observations in constraining the emissions.The posterior results were found to be very sensitive to background mixing ratios, with even slight increases in the baseline leading to significant decrease of emissions.

Life cycle climate performance evaluation (LCCP) of electric vehicle heat pumps using low-GWP refrigerants towards China's carbon neutrality

The environmental-friendly heat pump with low global warming potential (GWP), such as R1234yf, CO2, R290, and several potentially promising refrigerant mixtures, is increasingly essential for the electric vehicle (EV) to save energy consumption and extend the driving range. It is beneficial to achieve carbon neutrality by reducing both direct and indirect carbon emissions. Previously, the life cycle climate performance (LCCP) was a widely accepted metric to evaluate the carbon footprint of mobile air conditioning systems “from cradle to grave” for the internal combustion engine vehicle (ICEV), however, such LCCP analyses about EV heat pumps can hardly be found. To facilitate the EV industry and policymakers' better understanding of the environmental impacts of those low-GWP refrigerants, this study provided a comprehensive LCCP analysis for the EV heat pumps based on the system bench test results, local climates, local power supply characteristics, real-world driving patterns, vehicle cabin thermal sensation, and climate control load. Five low-GWP refrigerants, i.e., R1234yf, CO2, R290, binary blends of CO2 and R41 (with GWP values of 49), M2(R410A substitute with GWP values of 137), were compared against R134a and R410A in 31 provinces of mainland China. We also considered the impacts of electric vehicle adoption rates and the carbon intensity of electricity from 2020 to 2060. Results show that the total life-cycle emissions per vehicle are highly related to climate conditions in different provinces, while R290 shows the lowest emission on the national average. The national mean life-cycle emissions per vehicle are projected to decrease 14% by 2030 and 45.4% by 2060 under the current technological trajectory of electricity generation. By using low-GWP heat pump systems in EVs, the cumulative emissions counting all vehicles can be saved up to 1450 Mt. CO2e from 2020 to 2060.

Ways to use refrigerators that use heat to cool vehicles.

BACKGROUND: Today, most of the heat that is released during the combustion of fuel in internal combustion engines goes into the environment along with exhaust gases. However, additional energy can be used for refrigeration and air conditioning. Previously, there were only two ways to use exhaust heat for cooling: absorption machines and ejector chillers. But now, thanks to the development of organic Rankine cycles, there are new possibilities for cooling vehicles.
 AIMS: Conduct a theoretical analysis of the possibility of introducing mobile air conditioning and refrigeration systems in transport using various types of refrigeration machines that operate on the basis of heat.
 MATERIALS AND METHODS: Modeling of typical cooling cycles was carried out in the ASPEN HYSYS software environment. The most effective substances were selected from the absence of supercritical conditions.
 RESULTS: Depending on the selected cycle type, simulation results were obtained that corresponded to the calculated parameters. The coefficients of performance were determined under various ambient conditions and generator temperatures.
 CONCLUSIONS: A theoretical analysis of various cooling cycles for use in transport has been carried out. The results of the calculations show that the task of ensuring the cooling of the cabin or cargo is carried out even in the harsh operating conditions of the refrigeration system.

Energy consumption of mobile air-conditioning systems in electrified vehicles under different ambient temperatures

In 2019, passenger car CO2 emissions peaked at 3.2 billion metric tons globally. Despite efforts to curb vehicle CO2 emissions and the ambitious targets adopted for greenhouse gas mitigation in the European Union (EU), emissions from road vehicles increased steadily over the past decade. Electrified vehicles have gained significant market share in the last years and are an essential technical option to reduce CO2 emissions. Range anxiety and insufficient charging infrastructure limit electrified vehicles’ customer acceptance and market attractiveness. The use of auxiliary systems under certain circumstances may reduce vehicle range. In this regard, energy management improvements lead to better vehicle range results. As well-considered in numerous studies, the most consuming auxiliary system is the vehicle’s heating, ventilation and air-conditioning (HVAC) system, also known as Mobile Air-Conditioning (MAC). The present work explores the influence of different parameters on the energy consumption of the MAC system in plug-in hybrid vehicles (PHEV) and battery electric vehicles (BEV). For this purpose, one PHEV and one BEV were tested in laboratory conditions at different cell temperatures of −7°C (19.4°F), 22°C (71.6°F) and 35°C (95°F), over the Worldwide Harmonised Light vehicle Test Cycle (WLTC). Laboratory tests with the same conditions were repeated with MAC on and off for each temperature. For the reference 23°C (73.4°F) condition, additional factors affecting energy consumption were analysed, such as the impact of depleting/sustaining modes on the MAC performance in PHEV, or the effect of warm and cold start in PHEV and BEV. Results suggest that the electric energy required to heat the cabin at low temperature (−7°C) could be 4–10 times higher than the energy needed to cool down the cabin in hot conditions (35°C). Compared to the vehicle energy required at the wheels during a WLTC, the MAC impact at −7°C ranges from 35% to 45% while at 35°C goes from 15% to 18%.

Modeling and Optimization of a Micro-Channel Gas Cooler for a Transcritical CO2 Mobile Air-Conditioning System

This study focuses on developing and optimizing of a microchannel gas cooler model for evaluating the performance of a transcritical CO2 mobile air-conditioning system. A simulation model is developed with the aid of MATLAB R2022a. A segment-by-segment modeling approach is utilized by applying the effectiveness-NTU method. State-of-the-art heat transfer and pressure drop correlations are used to obtain air and refrigerant side heat transfer coefficients and friction factors. The developed model is validated through a wide range of available experimental data and is able to predict a gas cooler capacity and pressure drop within an acceptable range of accuracy. The average errors for a gas cooler capacity and pressure drop are 3.79% and 10.24%, respectively. Furthermore, a parametric optimization method is applied to obtain optimal microchannel heat exchanger dimensions, including the number of tubes, microchannel ports, and passes. Different combinations were selected within the practical range to obtain optimal dimensions while keeping the total core volume constant. The simultaneous effect of the number of tubes, the number of ports in each tube, and the number of passes is determined. The objective of the current optimization technique is to minimize the pressure drop for the specific design capacity under different operating conditions without changing the overall volume of the gas cooler. The average pressure drop reduction for the optimal geometry as compared with the baseline geometry under all operating conditions is about 15%. The results from this study can be used to select an optimal geometric design for the required design capacity with a minimal pressure drop without the need for expensive prototype development and testing.

Life cycle climate performance (LCCP) evaluation model for electric vehicle heat pumps and emission reduction analysis of low-GWP refrigerants

<p indent="0mm">With the proposal of China’s carbon neutrality target and the official entry into force of the Kigali Amendment to the Montreal Protocol, the green and efficient development of the new energy vehicle heat pump is imperative, since China has the largest number of new energy vehicles in the world. The environmental-friendly heat pump with low global warming potential (GWP) is increasingly essential for the electric vehicle (EV) to save energy consumption and extend the driving range, it is beneficial to achieve the carbon neutrality from reducing both direct and indirect carbon emissions. The long-used R134a has a great climate impact due to its high GWP, researchers have been investigating heat pump systems with low-GWP refrigerants. Previously, the life cycle climate performance (LCCP) was a widely accepted metric to evaluate the carbon footprint of mobile air conditioning systems “from cradle to grave” for the classical engine vehicle, however, the new energy vehicle heat pump has significant differences from the mobile air conditioning systems, which makes the LCCP developed for MAC systems no longer applicable for the NEV heat pump system. Such LCCP analysis about EV heat pumps can hardly be found. To facilitate the EV industry and policymakers better understand the environmental impacts of those low-GWP refrigerants, this study provides a comprehensive LCCP analysis for the EV heat pumps based on the heat pump system bench test results, local climates (six cities: Beijing, Shanghai, Guangzhou, Phoenix, Fargo, and Chicago), local power supply characteristics, real-world driving patterns, vehicle cabin thermal sensation, and climate control load. Three low-GWP refrigerants, i.e., CO₂, binary blends of CO₂ and R41 (with GWP value of 49), M2 (R410A substitute with GWP value of 137), were compared against R410A and R134a. Results show that the system COPs in the energy consumption model are estimated within ±6.5%; In most regions, the heat pump can save 36%–69% of electricity for heating on electric vehicles compared to the conventional PTC heater system; The direct emissions depend on the refrigerant GWP and are almost unaffected by the climate. The indirect emissions are influenced by the climate, refrigerant type and the carbon intensity; among the indirect emissions, manufacturing and EOL disposal account for only 5% or so, while the major part is the emissions due to system operation; The R410A heat pump shows higher levels than R134a in both direct and indirect emissions, with 11%–36% increase in total; although M2 shows 2%–27% higher indirect emissions than R134a, it reduces 90% of the direct emissions. In general, it shows 3%–35% less total emissions compared to R134a for EV heat pump application; the direct emissions of the CO₂ heat pump can be neglected while the CO₂ system can reduce 7% of the indirect emissions only in cold climates such as Fargo. Thanks to its low direct emissions, the total LCCPs of the CO₂ heat pump are reduced by 6%–27% relative to R134a except in Shanghai (+20%); among the selected refrigerants, CO₂/R41 shows the lowest LCCP, reducing 5%–42% of total emissions relative to R134a in various climates, and 1%–21% less than the CO₂ system.

A state of art review on future low global warming potential refrigerants and performance augmentation methods for vapour compression based mobile air conditioning system

A state of art review on future low global warming potential refrigerants and performance augmentation methods for vapour compression based mobile air conditioning system

A comprehensive study of drop-in alternative mixtures for R134a in a mobile air-conditioning system

• A comprehensive method to evaluate refrigerant alternatives is developed. • No mixture has higher COP, higher Q, lower GWP, and lower flammability than R134a. • Mixing R134a or R227ea with R152a creates a promising alternative to R134a. • The results of mixtures are compared to R134a and guide the design of alternatives. • The method can be extended for searching alternatives for other fluids. R134a will be phased out soon due to its high GWP. Replacing R134a with a low Global Warming Potential (GWP) and non– or slightly flammable fluids in the systems in stock should maintain the same level of system performance. This study focuses on the drop-in alternatives for R134a regarding a Mobile Air-Conditioning system. A simulation model coupled with a microchannel heat exchanger model is developed and validated for calculating the system Coefficient of Performance (COP) and capacity of the Mobile Air-Conditioning system. A comprehensive method is developed to evaluate the alternative candidates combining the performance simulation and the flammability estimated of mixtures. The evaluation includes the system performance, environmental impact, and flammability of alternative mixtures. 15 pairs of binary mixtures from six pure fluids (R134a, R1234yf, R1234ze(E), R32, R227ea, and R152a) with 99 compositions are evaluated as R134a drop-in replacements, and the results are discussed. There is no perfect mixture found that is nonflammable, has low GWP, and has higher system efficiency and capacity than R134a in this study. Using R152a as a drop-in replacement of R134a can increase the system efficiency and capacity, but R152a is flammable. By adding R134a or R227ea to R152a can reduce the flammability of the mixture. R152a/R134a, R152a/R1234yf, and R32/R152a have higher COP and capacity than R134a, but they are not safe or environmental friendly enough. The mixtures for replacing R134a as drop-in alternatives with low Global Warming Potential (less than 150 or 700), nonflammable or slightly flammable are listed and discussed. The method developed in this study can be extended to evaluate alternatives for replacing other working fluids in any thermal application that will be restricted.

MEXICHEM UK LTD v HONEYWELL INTERNATIONAL INC

H1 Patents – European patents – Revocation – Declaratory relief – Arrow declarations – Refrigerants for mobile air conditioning systems – Strike out application – Appeal to Court of Appeal

Cooling performance enhancement for the automobile transcritical CO2 air conditioning system with various internal heat exchanger effectiveness

• CO 2 system with internal heat exchanger (IHX) were investigated. • An experiment to change IHX under different conditions was designed. • Effects of IHX on system performance and parameters were studied. • Effect of various IHX under a wide working condition was analyzed. • Energy and exergy analyses with different IHX were conducted. Carbon dioxide (CO 2 ) is one of the promising refrigerant substitutes in mobile air conditioning system. To enhance the cooling performance, this paper presented an experimental investigation on the influence of the various internal heat exchanger (IHX) effectiveness on a transcritical CO 2 mobile air conditioning system. An experimental apparatus with regulatable IHX effectiveness was set up and tested. The effects of IHX effectiveness on the cooling capacities and coefficient of performance (COP) were studied under various outdoor air temperatures (30, 35 and 40 ℃) and compressor speeds (2000 to 7000 rev·min −1 ). Optimal discharge pressure and cycle state parameters with various IHX effectiveness were analyzed. Based on exergy perspective, the irreversibility of the main components and the cycle were discussed to give further reference for system optimization. Results showed that using IHX enhanced the COP of CO 2 system by the rates from 14.5% to 18.5% at various outdoor air temperatures. With increasing IHX effectiveness, the COP enhancement decreased, and the discharge temperature easily increased to its restriction value. The compressor and gas cooler occupied the main exergy losses of the system with IHX. The results could provide reference for the design and optimization of the CO 2 mobile air conditioning system.

Heat recovery design and test for the secondary loop heat pump MAC system

Abstract In mobile air conditioning (MAC) systems, the secondary loop (SL) structure was usually adopted when using flammable refrigerants such as R1234yf, R290 and R152a. The introduction of intermediate heat exchangers in SL system inevitably increased the temperature difference between the condensation side and the evaporation side, thereby increased the compressor power consumption and caused the performance attenuation. To overcome the attenuation, this study designed a heat recovery device which collects the waste heat from the passenger compartment to increase the evaporation temperature and reduce the compressor power consumption. Validation experiments were completed in a secondary loop heat pump (SLHP) MAC system using R152a and was compared with a baseline direct expansion (DX) system. According to experimental results, under the -10 °C outdoor temperature, the SLHP system showed performance attenuation compared with the DX system. With the increase in indoor temperature, the attenuation gradually increased to 8.96% at the indoor temperature of 20 °C. In this case, a heat recovery design was used in the SLHP system, which increased the coefficient of performance (COP) by 9.29% compared with the original SLHP system and achieved similar performance to the DX system.

Assessing fuel consumption reduction in Revercycle, a reversible mobile air conditioning/ Organic Rankine Cycle system

Organic Rankine Cycle (ORC) is a promising solution to improve vehicle efficiency, but its commercial success is hindered by the compactness and cost requirements of the automotive sector. In an attempt to overcome these limitations, a reversible mobile air conditioning (MAC)/ORC, hereafter called ReverCycle, is proposed in this work. ReverCycle is a compact system that operates in two different modes: a standard MAC system when cabin cooling is required or an ORC recovering mechanical energy from the waste heat of an engine’s cooling system.This study presents a simulation methodology to assess the ReverCycle fuel consumption gain. A global light duty vehicle model allows the estimation of the yearly working hours for each ReverCycle operating mode and quantifies the recovered mechanical energy in ORC mode. The ORC module is validated with experimental results. Validation has shown a normalized root-mean-square deviation between 5% and 11% for the main ORC variables (pressures, temperatures and electric powers).The average fuel consumption reduction in ReverCycle was 1.3 and 2% with cold start and hot start conditions, respectively. The reversible system lost 25% of the ORC waste heat recovery potential owing to MAC activation time; however, the significant reductions in cost and compactness were advantageous.

Thermoeconomic Analysis of a Mobile Air Conditioning Unit Using the Specific Exergy Cost (SPECO) Method

In recent years, many researchers have used exergy-based analysis and assessment methods such as exergy, exergoeconomic and exergoenvironmental as powerful tools to solve practical problems in the design and to improve energy-related systems. The main objectives of this contribution are to analyse and assess the performance of a mobile air conditioning (MAC) system from the thermoeconomic point of view that combines energy quality and economic issues. We used the specific exergy cost (SPECO) method to calculate exergy-related parameters and display cost flows for all streams and components in the whole system. In this context, we considered a vapour compressed MAC unit (utilizing R134a as a refrigerant) of a public bus with a capacity of 99 passengers and a volume of 69 m3. In the analysis, we utilized the real data obtained from the measurements. Based on the exergetic analysis, while the highest exergy destruction rate was determined to be 3.7 kW for the compressor, with a minimum value of 0.15 kW due to the condenser unit. Furthermore, through the SPECO method, the highest and lowest exergoeconomic factors belonged to the condenser with 0.63 and the expansion valve with 0.05, respectively.

Effect of thermostatic expansion valve tuning on the performance enhancement and environmental impact of a mobile air conditioning system

In this work, the performance enhancement of a HFO-1234yf mobile air conditioning (MAC) system with a suction/liquid line heat exchanger (SLHX) was carried out experimentally by tuning the thermostatic (constant superheat) expansion valve (TXV) and its impact on the environment was also evaluated. The optimum charge of HFO-1234yf and HFC-134a systems was found to be 670 g and 740 g, respectively. The results showed that the HFO-1234yf system with SLHX had better coefficient of performance (COP) and exergy efficiency when compared to HFC-134a system with SLHX at idling condition, whereas it had reduced performance at other speed conditions. The tuning of the TXV in the HFO-1234yf system had a positive influence on the COP, cooling capacity, and exergy efficiency and those were higher than that of existing HFC-134a system by 4.3–8.6%, 6.5–10.1%, and 3.7–5.1%, respectively, at idling and city speed conditions, whereas those were slightly lower at high-speed conditions. The total CO2 equivalent emission of tuned and un-tuned HFO-1234yf system was 27.98% and 24.64% lower than that of the existing HFC-134a system. The outcome of this study indicated that the SLHX implementation in the HFO-1234yf MAC system with tuned TXV could be a possible option to replace HFC-134a.

The Experimental Assessment of R134a and Its Lower GWP Alternative R1234yf in an Automobile Air Conditioning System

Reducing global warming potential (GWP) of refrigerants is needed to the decrease of ozone-depleting of refrigeration systems leakages. Refrigerant R1234yf is now used to substitute R134a inside mobile air conditioning systems. Thermodynamic properties of R1234yf are similar to R134a. Also, it has a very low GWP of 4, compared to 1430 for R134a, making it a proper choice for future automobile refrigerants. The purpose of this research is to represent the main operating and performance differences between R1234yf and R134a. Experimental analysis was carried out on the automotive air conditioning system (AACS) with 3 kW nominal capacity, to test and compare the performance of R134a with R1234yf. Experiments were accomplished for both refrigerants in almost the same working conditions and procedure with a range of ambient temperature varied from 26oC to 50oC. Parameters studied were ambient temperature, type of refrigerant in the system at compressor speed 1450 rpm, and internal thermal loads of passenger room. The performance characteristics of the system, including COP and cooling capacity, were studied by changing different parameters. The results show that COP of R134a is higher than R1234yf by 12.6%, while the refrigeration effect of R134a is higher than R1234yf by 25%. This shows that R1234yf is a suitable and good candidate for drop-in replacement of R134a in AACS.

Design optimization of bare tube heat exchanger for the application to mobile air conditioning systems

A louver fin heat exchanger (LFHX) has been widely used as an evaporator in the mobile air conditioning system due to its high heat transfer performance. However, there is an inherent problem of the LFHX such that it is poorly drained due to the fins. This causes problems with odor, corrosion, and window fogging. The purpose of the study is to investigate a bare tube heat exchanger (BTHX) to overcome LFHX problems while maintaining heat transfer and air-side pressure drop performance. In this context, heat transfer performances for both LFHX and BTHX were measured experimentally, and the numerical model of the heat exchanger was developed and validated. Then, the geometry model of the BTHX is optimized with five independent design variables. The approximated assisted optimization method is applied with the objectives of maximizing heat transfer performance and minimizing air-side pressure drop. A global sensitivity analysis is performed to analyze the effect of design variables on output performance. A dynamic dip test was performed to evaluate the drainage performance of heat exchangers. The performance of the optimized BTHX is compared with that of the LFHX and discussed the potential of the BTHX for the application to the mobile air conditioning systems.

Experimental studies on the performance of mobile air conditioning system using environmental friendly HFO-1234yf as a refrigerant

In this work, the experimental investigation on the performance and exergy analysis of mobile air conditioning system with suction line heat exchanger using environmental friendly HFO-1234yf was carried out under varied evaporator air flow rates. The performance was compared with existing HFC-134a results. The performance analysis showed that the cooling capacity and the coefficient of performance of the system with HFO-1234yf were lower than that of the HFC-134a by upto 2–11%. The power consumption and the volumetric efficiency of the compressor with HFO-1234yf were found to be 14.02% and 11.2% higher than that of HFC-134a. From the exergy analysis, it was observed that the major exergy destruction occurred in the compressor, followed by the condenser, evaporator, thermostatic expansion valve, and suction line heat exchanger for both refrigerants. The exergy efficiency of the system with HFO-1234yf was 2.4–12.6% lower than that of HFC-134a. From this study, it was observed that the losses experienced in the compressor, thermostatic expansion valve and evaporator lead to poor performance with HFO-1234yf.

Experimental research on charge determination and accumulator behavior in trans-critical CO2 mobile air-conditioning system

Natural refrigerant CO2 (R744) is one of next generation refrigerants in mobile air conditioner (MAC) application with superior environmental and heating performance. This paper investigated the charge characteristics and refrigerant migration behavior of a trans-critical CO2 MAC. A novel visualized accumulator with five observation mirrors was adopted to set up this CO2 MAC. A series of steady-state system experiments were carried out in a calorimeter facility to reveal the effects of refrigerant charge and EXV opening on system performance and accumulator behavior. In addition, the transient migration behavior of refrigerant during shutdown and start-up and the flow behavior of lubricant oil with 0.5 mm oil return hole were studied experimentally. It is found that a plateau region with optimal system performance occurred between 1100 g and 1600 g refrigerant charge. When the return hole becomes small, stratification of lubricant oil and liquid refrigerant was found in the accumulator.

Tuning thermostatic expansion valve for implementing suction line heat exchanger in mobile air conditioning system

The suction line heat exchanger is introduced in a mobile air conditioning system in order to achieve higher energy efficiency. Recent studies reveal that improvement in the system with suction line heat exchanger greatly depends on refrigerant properties and operating conditions. In this work, suction line heat exchanger was incorporated in a mobile air conditioning system and the spring force in the block-type thermostatic expansion valve of the modified system was adjusted (1) to match with the cooling capacity and (2) to match with the suction degree of superheat of the original system as two different cases. The refrigerant R134a was used in this study. The optimum charge of the mobile air conditioning system using R134a with suction line heat exchanger was experimentally found to be 740 g which was 19.4% higher than that of the original system. At optimum charge level before tuning the thermostatic expansion valve, the coefficient of performance (COP) of the system was increased by 2.8%, while the cooling capacity was reduced by 6%. After retuning the thermostatic expansion valve to match the original cooling capacity, the COP of the system improved by 11.8% with 10.5% lesser power consumption than that of the original system. With retuned thermostatic expansion valve for the original degree of superheating, the cooling capacity and COP of the system were increased by 6.7% and 16.2%, respectively. From this experiment, it is concluded that the mobile air conditioning system using R134a as a refrigerant with suction line heat exchanger performs better with suitable retuning of thermostatic expansion valve for the same degree of superheating than that is tuned for same cooling capacity.