Automobile Air Conditioning Research Articles

Bill would authorize U.S. reduction of HFCs

Manufacturers of hydrofluoroolefins (HFOs), a new generation of refrigerants that have very low potential to cause global warming, are getting a boost from the U.S. Congress. Republicans and Democrats in the Senate are backing a bill (S. 2448) that would authorize EPA to ratchet down the production of hydrofluorocarbons (HFCs), a class of refrigerants that are potent greenhouse gases. HFOs are beginning to replace HFCs in vehicle air conditioners, store refrigerators, and vending machines. EPA restricted the use of HFCs and refrigerant blends containing HFCs in a 2015 rule. But Mexichem Fluor and Arkema, which make HFC-134a (1,1,1,2-tetrafluoroethane), challenged the regulation. HFC-134a has long been used as a refrigerant in car air conditioners. A federal court sided with the two companies last year. It faulted EPA for basing the regulation on part of the Clean Air Act authorizing the agency to require replacement of compounds that deplete stratospheric ozone with

Impacts of the Degradation of 2,3,3,3-Tetrafluoropropene into Trifluoroacetic Acid from Its Application in Automobile Air Conditioners in China, the United States, and Europe.

HFO-1234yf (2,3,3,3-tetrafluoropropene) was proposed as an automobile air conditioner (MAC) refrigerant worldwide. However, its atmospheric degradation product is the highly soluble and phytotoxic trifluoroacetic acid (TFA), which persists in aquatic environments. We used a global three-dimensional chemical transport model to assess the potential environmental effects resulting from complete future conversion of the refrigerant in all MAC to HFO-1234yf in China, the United States, and Europe. The annual mean atmospheric concentrations of HFO-1234yf were 2.62, 2.20, and 2.73 pptv, and the mean deposition rates of TFA were 0.96, 0.45, and 0.52 kg km-2 yr-1, in three regions. The regional TFA deposition sources mainly came from emissions within the same region. The annual TFA deposition in the North Pole region was lower than the global average and mainly originated from European emissions. A potential doubling in the future HFO-1234yf emissions in China mainly affected the local TFA depositions. The TFA concentrations in rainwater were strongly affected by the regional precipitation rates. North Africa and the Middle East, regions with scant rainfall, had extremely high TFA concentrations. The rainwater concentrations of TFA during individual rain events can exceed the level considered to be safe, indicating substantial potential regional risks from future HFO-1234yf use.

PENERAPAN LAPORAN KEUANGAN BERDASARKAN SAK ETAP PADA BENGKEL EVRY SERVICE AC MOBIL KOTA LUBUKLINGGAU

The purpose of this research is To apply Financial Reporting based on SAK ETAP on Evry Service Workshop of Car Air Conditioner period 2014-2016, research type is quantitative research with approach of theory, technique of data collecting in this research is using document and observation. The data analysis technique used is quantitative data. The result of the research is for the amount of Asset Evry Service Car AC Service for Rp. 451.205.000,00 thus the assets owned as a support activity activities during the accounting period. Earnings Profit obtained Evry Service Workshop AC Car for Rp. 252.280.000,00. For cash increase in Evry Service Workshop AC Car for Rp. 309.105.000,00.From the report of changes in capital Evry Service Workshop AC The car gets an additional capital from profit plus initial capital then it can be the final capital of Rp. 377.280.000,00. The application of financial reporting based on SAK ETAP in Evry Service Car Air Conditioner Service is Income Statement in 2014 amounting to Rp.251.750.000,00, 2015 Rp.228.355.000,00 and 2016 for Rp.252.280.000,00. Statement of Changes in Equity in 2014 amounting to Rp.376.750.000,00, year 2015 of Rp.353.355.000,00 and year 2016 of Rp.377.280.000,00. The balance sheet in 2014 total assets with total liabilities and equity of Rp.431.310.000,00, year 2015 amounting to Rp.450.218.000,00 and year 2016 amounting to Rp.451.205.000,00. And Cash Flow Statement in 2014 amounting to Rp.296.750.000,00 in 2015 amounting to Rp.318.355.000,00 and 2016 for Rp.309.105.000,00.Keywords: SAK-ETAP, Financial Statements

Performance improvements evaluation of an automobile air conditioning system using CO2-propane mixture as a refrigerant

The main purpose of this work is to enhance the energy efficiency of CO2 automobile air conditioning system. Theoretical analysis demonstrated that the mixture of CO2 and propane can improve its performance, thus, experiments have been carried out to see effects of various CO2-propane mass fractions of 100/0, 90/10, 80/20, 70/30, 60/40, 50/50 on the system performance at different ambient temperatures and gas cooler frontal air velocities. Experimental results show similar trends with those from the theoretical results. It has been shown that under the same compressor speed, system COP reaches highest at 60% of CO2 mass fraction, which is 29.4% higher than pure CO2 system and even achieves equal level of the R134a system, the optimum pressure and discharge temperature are reduced up to a maximum of 40% and 47 °C during the research range. Furthermore, comparison was carried out under the same cooling capacity by adjusting compressor speed for different mass fraction of CO2, results demonstrate that the use of CO2-propane mixtures yields a maximum COP rise of 22%even when cooling capacity is kept constant. A new optimum high pressure control algorithm for the transcritical CO2-propane mixture cycle has been developed based on the experimental data within a deviation of 5%.

Investigation on the improvement of car air conditioning system performance using an ejector

The purpose of this research is to know the improvement of car air conditioner system performance using an ejector. The study was conducted on a car engine with power 100 PS (74 kW) @ 5000 rpm. The test procedure is carried out under two conditions: the normal refrigeration cycle mode and the refrigeration cycle mode with the ejector. The working fluid used in the refrigeration cycle is R-134a. Performance data was measured on engine revolutions ranging from 1500 - 3000 rpm. Finally, the results showed that ejector usage on AC system generates an increase in the refrigeration effect and coefficient of performance (COP) of 25% and 22%, respectively. This has implications to better cooling capacity and compressor work that is lighter.

Spirosoma carri sp. nov., isolated from an automobile air conditioning system.

A Gram-stain-negative and yellow-pigmented bacterial strain, designated TX0406T, was isolated from an automobile evaporator core collected in Korea. The cells were non-motile, aerobic and rod-shaped. The strain grew at 15-37 °C (optimum, 25 °C), at pH 6.0-7.0 (optimum, 6.5) and in the presence of 0-1.5 % (w/v) NaCl. Phylogenetically, the strain was related to members of the genus Spirosoma(93.7-90.7 % 16S rRNA sequence similarities) and showed the highest sequence similarity of 93.7 % to Spirosomapulveris JSH5-14T. The major fatty acids of the strain were summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), C16 : 1ω5c and C16 : 0. The predominant menaquinone was MK-7. The polar lipid profile revealed the presence of phosphatidylethanolamine, an unidentified aminolipid, unidentified aminophospholipids and unidentified lipids. The DNA G+C content of the strain was 58.7 mol%. Based on phenotypic, genotypic and chemotaxonomic data, strain TX0406T represents a novel species in the genus Spirosoma, for which the name Spirosoma carri sp. nov. (=KACC 19013T=NBRC 112494T) is proposed.

Control of flash gas bypass MAC system with emphasis on start-ups and transients

Most of the previous research on flash gas bypass (FGB) focused on performance improvement in steady state and demonstrated that compared to direct expansion mode (DX), FGB mode have better performance. However, the control strategy of flash gas bypass system and dynamic behavior during start-ups and transients were not yet clearly defined and investigated. In this paper, a novel control strategy has been proposed for an automobile air conditioning system operating in flash gas bypass mode with R134a as the refrigerant. The proposed control strategy utilized an electronic expansion valve (EV) for the control of subcooling from condenser outlet and a bypass valve (BV) for superheat from compressor inlet. Both start-up and transient system behaviors were studied. The experimental results showed that the proposed cycle control strategy was found to be able to provide reliable control to the system. In addition, proper sizing of bypass valve and flash gas bypass tank have also been studied.

Spirosoma metallum sp. nov., isolated from an automobile air conditioning system

A Gram-stain-negative and yellow-pigmented bacterial strain, designated TX0653T, was isolated from an automobile evaporator core collected in Korea. The cells were aerobic and rod-shaped. The strain grew at 10-28°C (optimum, 25°C), at pH 6.0-7.5 (optimum, 6.5), and in the presence of 0-1% (w/v) NaCl (optimum, 0%). Phylogenetically, the strain was related to members of the genus Spirosoma (95.1-90.8% 16S rRNA sequence similarity) and distantly related to Spirosoma pulveris JSH5-14T (95.1%), Spirosoma fluviale MSd3T (95.0%), Spirosoma endophyticum DSM 26130T (94.8%), and Spirosoma linguale DSM 74T (94.6%). The major fatty acids of the strain were summed feature 3 (C16:1 ω6c and/or C16:1 ω7c), C16:1 ω5c, iso-C15:0, iso-C17:0 3-OH, and C16:0. MK-7 was identified as the predominant menaquinone. The polar lipids profile indicated the presence of one phosphatidylethanolamine, one unidentified aminolipid, one unidentified aminophospholipid, two unidentified phospholipids, and three unidentified lipids. On the basis of the phenotypic, genotypic, and chemotaxonomic characteristics, strain TX0653T represents a novel species in the genus Spirosoma, for which the name Spirosoma metallum sp. nov. (=KACC 19278T=NBRC 112495T) is proposed.

The Alternative Way to Drive the Automobile Air-Conditioning, Improve Performance, and Mitigate the High Temperature: A Literature Overview

Over fuel consumption and increasing in CO2 emissions are problems as compensation from the imposition of automobile A/C systems. Another problem is the extreme temperature when the car is parked under sunlight so that the thermal load becomes very large when A/C is turned on. Therefore, this article presents various methods to overcome the problem. Methods to reduce fuel consumption and to reduce CO2 emissions are done by application of VCC and the absorption system. Potential of turbo A/C system and combining vapor compression and LPG fuel system has also been studied. Potential of turbo A/C system and combining vapor compression and LPG fuel system has also been studied. Related to the mitigating of high temperature inside the car cabin when parked under sunlight, the addition of a ventilator and portable car cooling system is a promising option.

Investigating performance of microchannel evaporators for automobile air conditioning with different port structures

Microchannel evaporator has been widely applied in automobile air conditioning, while it faces the problem of refrigerant maldistribution which deteriorates the thermal performance of evaporator. In this study, the performances of microchannel evaporators with different port structures are experimentally investigated for purpose of reducing evaporator pressure drop. Four evaporator samples with different port number and hydraulic diameter are made for this study. The performances of the evaporator samples are tested on a psychometric calorimeter test bench with the refrigerant R-134A at a real automobile air conditioning. The results on the variations of the evaporator pressure drop and evaporator surface temperature distribution are presented and analyzed. By studying the performance of an evaporator, seeking proper port structure is an approach to reduce refrigerant pressure drop as well as improve refrigerant distribution.

Optimization of Process Parameters in Injection Molding of Mounting Panel of Automobile Air Conditioner Housing Based on Moldflow and Taguchi Orthogonal Experiment

Injection molding simulation of mounting panel of automobile air conditioner housing was carried out with Moldflow software. Aiming at the warpage and sink mark existing in forming process, orthogonal experiment was designed by using Taguchi method to analyze the influence of main process parameters on warping deformation and sink mark depth, and the optimal combination of process parameters in injection molding was obtained.

Comparative Evaluation of an Automobile Air - Conditioning System Using R134a and Its Alternative Refrigerants

Abstract This research involves the theoretical aspects of R134a automobile air conditioning system. The main aim of the research is to evaluate the different alternative refrigerants as a drop in substitute of R134a theoretically. For this purpose, thermodynamic properties of different alternative refrigerants i.e. R290, R600a, R407C, R410A, R404A, R152a and R1234yf are compared to R134a. Thermodynamic evaluation of standard rating cycle of vapour compression refrigeration system is carried out. Engineering equation solver and refprop soft wares have been used for the thermodynamic analysis purpose. From thermodynamic analysis, it is derived that R1234yf is best suitable alternative refrigerants as a drop in substitute of R134a. R1234yf has lower coefficient of performance as compared to R134a; however it is best suitable alternative refrigerants as a drop in substitute because it has very low global warming potential and can be substituted in the existing automobile air conditioning system with minimum modification.

Comparative study of thermo-physical properties of SiO2 and Al2O3 nanoparticles dispersed in PAG lubricant

Currently, the possibility to enhance fuel efficiency with cutting edge advancements is thoroughly investigated by researchers. One of the best ways to increase the fuel efficiency is by improving the performance of the automobile air conditioning system. As a result, nanoparticles are dispersed in the lubricants of automobile air conditioning compressor for heat transfer and tribology enhancement. In this paper, viscosity and thermal conductivity of the SiO2 nanoparticles dispersed in Polyalkylene glycol (PAG) lubricants for 0.2–1.5% volume concentrations and 303–353K working temperatures was investigated and compared with Al2O3 nanolubricant. The viscosity and thermal conductivity of the nanolubricants increased with volume concentration but decreased with temperature. The paper proposed correlations for viscosity and thermal conductivity of SiO2 nanolubricants at various concentrations and temperatures. The allowable volume concentration of SiO2 and Al2O3 nanolubricants for application in automobile air conditioning compressors are up to 1.0% and 0.3%, respectively. The thermal conductivity of SiO2 nanolubricants at 1.0% concentration is higher than Al2O3 nanolubricants at 0.3% allowable concentration. As a conclusion, it is advisable to use the SiO2 nanolubricants with volume concentration of less than 1.0% for applications in automotive air conditioning system.

Experimental investigations on automobile air conditioners working with R134a and R290/R600a as an alternative

In this work, the performance of R134a based automobile air conditioning system has been evaluated by retrofitted with R290/R600a mixture (in the ratio of 50:50, by mass), as an alternative. The performance was evaluated at five different operating speeds (1000, 1500, 2000, 2500, and 3000, which covers the entire range of working conditions) with four different cabin load (100, 200, 300, and 400 W). The condenser inlet air temperature was varied in the range between 30 and 50°C, which covers the entire climatic variations in Coimbatore city of India. The performance characteristics such as, refrigerating effect, coefficient of performance, compressor power consumption, and compressor discharge temperatures were considered for comparison. The results showed that, hydrocarbon mixture has faster cooling rate due to its high latent heat of vaporization, 5% higher coefficient of performance due to higher refrigeration effect, 8-10 K lower compressor discharge temperature due to its lower specific heat ratio with 5% lower compressor power consumption due to its lower viscosity and lower liquid density. The charge requirement of R290/R600a mixture is about 50% less compared to R134a. However, the mixture composition is considered as an interment replacement in automobile air conditioners due to composition shift under leak-age conditions. Hence, R290/R600a mixture is considered as an interim energy efficient and environment friendly option in R134a automobile air conditioners to extend its life.

Influence of compressor’s tilt angle on the performance of miniature refrigeration system

Vapor compression refrigeration is considered as ideal miniature cooling system for miniature electronic systems and portable cooling systems. Many applications of the miniature refrigeration system are working under the situations (such as aviation field, individual combat system and automobile air conditioning, etc.) that exist bump, tilt, and even flip, which will severely degrade the performance of the miniature refrigeration system. In order to study the influence of compressor’s tilt angle on refrigeration system, a test bench was built and the performance experiments were made. The results show that the compressor’s tilt angle has a great impact on the refrigeration system performance. When the compressor worked at the maximum tilt angle of 60°, COP-c and COP-h of the system change periodically. When the compressor works in full load, the maximum tilt angle for compressor is 20°. When the compressor tilt angle is 15°, there is an optimal amount of refrigerant charge, and corresponding COP-c and COP-h reach the maximum of 2.9 and 3.9, respectively.

Performance evaluation of a waste-heat driven adsorption system for automotive air-conditioning: Part I – Modeling and experimental validation

Adsorption systems driven by engine waste heat are one of the possible alternatives to the conventional automobile air conditioning in terms of energy savings and environmental issues. Assessment of this issue are carried in a two-part study. In this first part I, theoretical and experimental investigations were performed on a two bed, silica gel adsorption chiller for automotive applications. A prototype adsorption system with a total weight of about 86 kg was developed and tested to driven by low-grade waste heat. The single adsorbent bed consisted of three plate-fin heat exchangers connected in parallel. An improved non-equilibrium lumped parameter model was developed to predict the transient performance of the system. The model is fully dynamic and takes into account the mass transfer resistance and pressure drop for each component of the system. The results showed that the model is able to accurately predict the dynamic performance of the system under different operating conditions and configuration modes with a short calculation time. The tested chiller was able to produce an average cooling capacity of about 2.1 kW with a COP of 0.35 at the rated operating conditions. Heat recovery system results in increasing the COP by 43% and the cooling power by 4%.

Experimental research and optimization on the environmental friendly R1234yf refrigerant in automobile air conditioning system

Currently, the refrigerant used in the automotive air conditioning system is R134a which has a high global warming potential (GWP) value, so people are eager to find a good replacement for it. According to recent studies, R1234yf is considered as one of the top candidates to replace R134a. In this article, the performances of R1234yf “drop-in” system and the optimization to the R1234yf system are experimentally studied and investigated. The expansion valve used for the R1234yf system is optimized by changing the charged fluid and adjusting the spring force. The results indicate that it can improve the performance of R1234yf system significantly through adjusting the thermostatic expansion valve. For the thermostatic expansion valves (TEVs) charged with R134a in thermal bulb, the system performance is optimal. Compared to the original expansion valve, for the R1234yf system applying the adjusted expansion valves, under different working conditions the cooling capacity increases by 11.3% averagely and the coefficient of performance (COP) increases by 8% averagely.

Design features of fan assembly in automobiles

Nowadays in the engine cooling system and in air-conditioning system of passenger compartment and cabin of tractor is applied a great variety of designs of fan units for the supply of cooling air. A distinctive feature of fan units of automobiles is that they need not only to supply cooling air, but also must make efficient use of air flow. This is not an easy task, because these two functions are almost always in conflict. The problem becomes even more complicated when a car air conditioner is installed. Efficiency factor of the incident flow is higher than the efficiency of the fan. It is therefore necessary to use more efficient the incoming air flow. The article analyzes the most common fan assemblies of automobiles used for the operation of the engine cooling and passenger compartment air conditioning system. Its strengths and weaknesses were evaluated. There were evaluated the most important characteristics: the effectiveness of the fan use, the rational use of air flow when the vehicle is moving, mass-dimensional characteristics and the noise produced by the fans in their work. The conclusions and recommendations for improving the fan installations were given. When choosing one or another variant of the fan assembly it is needed to take into account the features of the automobile design. High efficiency of fan can be obtained when the fan shroud has a full coverage of the radiator. In this case, for rational use of incoming flow is necessary to install in the fan cover the valves of a large cross-section in contrast to traditional, these valves must be driven to forced opening and closing.

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

In this paper, a comparative study of the second law of thermodynamics is presented to determine the possibility of using HFO-1234yf, an environmentally friendly refrigerant, as a drop-in replacement of HFC-134a in automotive air conditioning system. For the thermodynamic analysis, a computer program is written to simulate the operating conditions of automobile air conditioning system. The thermodynamic properties of the refrigerants are extracted from the REFPROP 8.0 software. For calculating the coefficient of performance (COP), exergy destruction, exergy efficiency and entropy generation, computational models are used to evaluate the effects of different parameters on their changes. It is found that using HFO-1234yf as the air conditioning refrigerant leads to higher exergy efficiency compared to HFC-134a. Also, maximum entropy generation and exergy destruction occur in the compressor. The exergy destruction and entropy generation of the cycle components are less in the case of using HFO-1234yf refrigerant instead of HFC-134a.

Fabrication of hydrophobic/hydrophilic switchable aluminum surface using poly( N -isopropylacrylamide)

Abstract The quick removal of condensed water generated during operation of an automobile air conditioner is essential to prevent the growth of bacteria and fungi, which may produce odors and cause illness. Modification of an evaporator core (evacore) surface to provide superhydrophobicity is one technique that can be used to remove the condensed water. However, if the evacore surface is superhydrophobic, small water droplets can flow towards the inside of the automobile engine along with the air flowing through the air conditioner. In the present investigation, we propose an approach to fabricate an evacore surface that can be switched from hydrophobic to hydrophilic by changing the temperature. In the initial stage of air conditioner operation, the surface is hydrophilic at ambient temperature, causing water to stay on the surface. After the operation of the air conditioner, the surface becomes hydrophobic at a higher temperature, and the water rolls off the surface. To fabricate this surface, aluminum (Al) substrate was used, and it was etched by immersion in 10 wt.% hydrochloric acid (HCl) for 8 min. The etched Al substrate was coated with a functionalized poly(NIPAM- co -MAA) polymer by immersing in a coating solution for 1 h at 120 °C. The resulting surface is a thermosensitive hydrophobic/hydrophilic switchable Al surface, which provides a hydrophilic state under the lower critical solution temperature (LCST), 35 °C, and a hydrophobic state above the LCST.