Experimental analysis of the low-GWP refrigerant R1234yf as a drop-in replacement for R134a in a typical mobile air conditioning system

2012 ◽  
Vol 226 (11) ◽  
pp. 2713-2725 ◽  
Author(s):  
Yu Zhao ◽  
Zhaogang Qi ◽  
Jiangping Chen ◽  
Baixing Xu ◽  
Bin He
Keyword(s):  
Working Conditions ◽  
Air Conditioning ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Laminated Plate ◽  
Improve Performance ◽  
Air Conditioning System ◽  
Expansion Valve ◽  
Variable Displacement ◽  
Valve Opening

This study investigated the performance of a typical mobile air conditioning system using R134a and R1234yf as the working fluids under different working conditions. The system is composed of a microchannel parallel flow condenser, a laminated plate evaporator, a variable displacement compressor, and a thermal expansion valve. The different working cycles of each refrigerant were comprehensively compared. The optimum refrigerant charge amount of the R1234yf system was approximately 95% of the R134a system during drop-in tests. The performance of the R134a system was a little higher than that of the R1234yf system. The cooling capacity and system coefficient of performance of the R134a system were 12.4% and 9% larger, respectively. This result is mainly because of the thermophysical property differences between the two refrigerants and the improper expansion valve opening of R1234yf. Analysis on the whole cycle revealed that the R1234yf system could obtain a higher evaporating pressure and a larger superheat and subcooling. Redesigning the expansion valve for R1234yf could improve performance of the system.

scholarly journals Experimental and Theoretical Study on the Cooling Performance of a CO2 Mobile Air Conditioning System

Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1927 ◽  
Author(s):  
Dandong Wang ◽  
Binbin Yu ◽  
Junye Shi ◽  
Jiangping Chen
Keyword(s):  
Air Conditioning ◽  
Theoretical Study ◽  
Cooling Capacity ◽  
Air Conditioning System ◽  
Cooling Performance ◽  
System A ◽  
Hfc 134A ◽  
Expansion Valve ◽  
The Impact ◽  
Compressor Efficiency

CO2 (GWP = 1) is considered as a promising natural alternative refrigerant to HFC-134a in mobile air conditioning (MAC) applications. The objective of this study is to investigate the cooling performance characteristics of a CO2 MAC system. A prototype CO2 MAC system, consisting of a CO2 electrical compressor, CO2 parallel flow microchannel heat exchangers, and an electrical expansion valve, was developed and tested. Factor analysis experiments were conducted to reveal the effect of outdoor temperature on the cooling performance of this CO2 MAC system. Compared with a conventional R134a MAC system, the prototype CO2 MAC system achieved comparable cooling capacity, but had COP reductions of 26% and 10% at 27 °C and 45 °C outdoor conditions, respectively. In addition, based on refrigerant properties, theoretical cycle analysis was done to reveal the impact of evaporator, gas cooler and compressor, on the system cooling performance. It is concluded that the increase of overall compressor efficiency or the decrease of gas cooler approaching temperature could greatly improve the COP of this CO2 MAC system.

scholarly journals Thermal Performance Analysis of Low-GWP Refrigerants in Automotive Air-Conditioning System

2020 ◽  
Vol 2020 ◽  
pp. 1-14 ◽  
Author(s):  
Yousuf Alhendal ◽  
Abdalla Gomaa ◽  
Gamal Bedair ◽  
Abdulrahim Kalendar
Keyword(s):  
Air Conditioning ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Exergy Destruction ◽  
Air Conditioning System ◽  
Capacity Coefficient ◽  
Automotive Air Conditioning ◽  
Automotive Air Conditioning System ◽  
Compressor Power ◽  
Low Global Warming Potential

The energy and exergy of low-global warming potential (GWP) refrigerants were investigated experimentally and theoretically. Refrigerants with a modest GWP100 of  ≤ 150 can be sufficient for bringing down emissions which were concerned for the automotive air-conditioning system. Three types of low-GWP refrigerants, R152a, R1234yf, and R1234ze(E), were examined with particular reference to the current high-GWP of R134a. The effect of different evaporating and condensing temperatures in addition to compressor speed was considered. The purpose was to bring a clear view of the performance characteristics of possible environment friendly alternatives of R134a. The analysis was carried out with compressor power, cooling capacity, coefficient of performance, exergy destruction, and exergy efficiency. It was noted that the total exergy destruction of R1234yf was reduced by 15% compared to that of R134a. The refrigerant R1234ze(E) has the highest energetic and exergetic performance compared with the other investigated refrigerants.

Performance of Automotive Air-Conditioning System by Using Ejector as an Expansion Device

2016 ◽  
Vol 819 ◽  
pp. 216-220
Author(s):  
Firdaus Mat Jusoh ◽  
Henry Nasution ◽  
Azhar Abdul Aziz ◽  
Sumeru ◽  
Afiq Aiman Dahlan ◽  
...  
Keyword(s):  
Air Conditioning ◽  
Internal Heat ◽  
Experimental Period ◽  
Cooling Capacity ◽  
Time Interval ◽  
Expansion Process ◽  
Air Conditioning System ◽  
Automotive Air Conditioning ◽  
Expansion Valve ◽  
Automotive Air Conditioning System

An automotive air conditioning system that uses thermal expansion valve (TEV) as an expansion device. The pressure drop from the condenser and evaporator pressure is considered an isenthalpic process (constant enthalpy), where this process causes energy loss (entropy generation) in the expansion process. The ejector recovers energy losses, which was previously lost in the expansion valve, and an ejector can be used to generate isentropic condition in the expansion process. The use of an ejector as an expansion device in this study can reduce power consumption of the compressor and increase cooling capacity of the evaporator. The experiments were conducted with temperature set-points of the conditioned space of 21, 22 and 23°C with internal heat loads of 100, 200 and 400 W. Measurements were taken during the one hour experimental period at a time interval of five minutes. The experiment results indicate that the ejector system is better than TEV and save fuel.

scholarly journals Experimental Thermodynamic Investigation on the Refrigerant Charge in a Transcritical CO2 Electric Bus Air Conditioning System

2021 ◽  
Vol 11 (12) ◽  
pp. 5614
Author(s):  
Haidan Wang ◽  
Shengbo Li ◽  
Yulong Song ◽  
Xiang Yin ◽  
Feng Cao ◽  
...  
Keyword(s):  
System Performance ◽  
Air Conditioning ◽  
Cooling Capacity ◽  
Exergy Efficiency ◽  
Coefficient Of Performance ◽  
Air Conditioning System ◽  
Electric Bus ◽  
Maximum Coefficient ◽  
Considerable Impact ◽  
Air Conditioning Systems

Due to its considerable impact on climate, bus air conditioning systems are being pushed to take a new and sustainable path. Electric buses relying on transcritical CO2 air conditioning units are perceived to be eco-friendly and future-proof solutions to achieving such a target. However, in order to have highly efficient air conditioning systems, the CO2 charge needs to be optimized. In this paper the energy and exergy-based analyses were performed to investigate the effect of normalized refrigerant charge on the system performance by using a test rig of a transcritical CO2 air conditioning unit for an 8 m electric bus. Results showed that the normalized refrigerant charge range of 0.248~0.336 was recommended in order to ensure the maximum coefficient of performance (COP). In addition, in sufficient charge conditions, the optimal COP, cooling capacity and exergy efficiency were 1.716, 18.97 kW and 29.79%, respectively, under the standard refrigeration condition of 35 °C/27 °C. As the ambient temperature rose from 35 °C to 40 °C, the COP, cooling capacity and exergy efficiency decreased by 16.03%, 10.90% and 12.22%, respectively. Furthermore, the exergy efficiency was found not to be sensitive to slightly insufficient charge, whereas overcharge was observed to be even beneficial to exergy efficiency under the condition of ensuring the maximum COP. In addition, insufficient refrigerant charging seriously affected the irreversible losses in the indoor and outdoor heat exchangers, whereas slight overcharge had little effect on the component exergy efficiency. Finally, the need to improve the CO2 compressor efficiency to enhance the system performance was revealed.

Design and performance analysis of a thermoelectric air-conditioning system driven by solar photovoltaic panels

2020 ◽  
pp. 095440622097616
Author(s):  
Moustafa M Aboelmaaref ◽  
Mohamed E Zayed ◽  
Ammar H Elsheikh ◽  
Ahmed A Askalany ◽  
Jun Zhao ◽  
...  
Keyword(s):  
Air Conditioning ◽  
Volume Flow Rate ◽  
Cooling Capacity ◽  
Vital Role ◽  
Input Current ◽  
Coefficient Of Performance ◽  
Thermal Loads ◽  
Air Conditioning System ◽  
Climate Conditions ◽  
Daily Average

Solar cooling technologies can play a vital role in renewable energy applications development. Thermoelectric systems have shown promising advantages over traditional refrigeration systems such as high thermal comfort, active adaptability, no moving parts, and refrigerants free. In this work, a novel thermoelectric air-conditioning system (TEACS) driven by photovoltaics (PV) is experimentally and theoretically investigated under the hot climate conditions of Sohag city (30°26′N, 42°31′E), Egypt for air conditioning of a typical small-size office room under different thermal loads. During day time, PV panels produce electricity which utilized to drive the TEACS directly and to charge batteries that store electricity to be exploited during nighttime. Moreover, a numerical model implemented in TRNSYS coupled with MATLAB software is developed to evaluate the performance of the proposed TEACS. The influences of varying the input electric current on the coefficient of performance (COP), cooling capacity, and average air room temperature are also studied. The results showed that a design point with an input current of 2.5 A for a cooling capacity of 30 W could be selected to maximize the cooling performance, in which the COP of the TEACS is found to be 2.2. Moreover, the daily average air temperature of the conditioned room was found to be 23.5, 25.5, 27.5, 28.5, and 30.5  °C for internal thermal loads of 0.0 W, 65.0 W,130.0 W, 195.0 W, and 260.0 W, respectively, at average air intake temperature of 36  °C, daily average input current of 4.28 A and air volume flow rate of 14.4 m3/h. It can be concluded that the TEACS powered by PV could be considered as a proper alternative to the traditional vapor compression systems.

scholarly journals Performance assessment of alternate refrigerants for retrofitting R22 based air conditioning system

2018 ◽  
Vol 22 (2) ◽  
pp. 931-941 ◽  
Author(s):  
Mian Saeed ◽  
Shafiq Qureshi ◽  
Khurram Hashmi ◽  
Muhammad Khan ◽  
Syed Danish
Keyword(s):  
Ozone Depletion ◽  
Air Conditioning ◽  
Cooling Capacity ◽  
Air Conditioning System ◽  
Suitable Alternative ◽  
Energy And Exergy ◽  
Expansion Valve ◽  
Exergy Performance ◽  
Lower Discharge ◽  
Ozone Depletion Potential

The performance of zero ozone depletion potential refrigerants is investigated when retrofitted in R22 based air conditioning system. The options evaluated are R407C, R417A, R422D, R427A, and R438A. In order to arrive at most suitable alternative(s) to R22, energy and exergy performance of candidate refrigerants is carried out and compared against that of R22. The COP and exergy efficiencies showed that none of selected refrigerant is as efficient as R22 however their values suggests that each may be considered as potential substitute for retrofitting. Having comparable COP to others but low cooling capacity of R417A makes it less attractive. With comparatively reduced COP, lowest exergy efficiency and highest mass-flow rate, makes R422D the least desirable option. The R407C, R427A, and R438A emerged as most attractive substitutes. The lower discharge temperatures of substitutes will enhance the compressor life. Further, for substitutes there may be a possible change out of expansion valve.

scholarly journals EFFECT OF AIR FLOW OBSTRUCTION IN A CONDENSING UNIT ON SPLIT AIR CONDITIONER PERFORMANCE

2020 ◽  
Vol 82 (5) ◽  
Author(s):  
Andriyanto Setyawan
Keyword(s):  
Air Conditioning ◽  
Air Flow ◽  
Cooling Capacity ◽  
Input Power ◽  
The Other ◽  
Coefficient Of Performance ◽  
Air Conditioner ◽  
Air Conditioning System ◽  
Heat Rejection ◽  
Other Hand

Obstructions of air flow in the outdoor unit could block the condenser air flow and reduce its heat rejection As a result, it could decrease the performance of a room air conditioning system. The paper presents the effects of the air flow obstruction of a condensing unit on the performance of a split-type air conditioner with refrigerant R410A. The study was conducted experimentally by employing front and side obstructions with varied distance from the condensing unit. The front obstruction of 100 cm height was applied at varied distance from 10 cm to 100 cm, while the side obstruction of the same height was applied at distance of 5, 10, and 15 cm. The presence of air flow obstructions results in the decrease of cooling capacity and coefficient of performance (COP). On the other hand, it increases the input power of the AC unit. From the experiment, it is obvious that the distance of front obstruction of 10 cm results in the reduction of cooling capacity by 46% and COP by 56%. It is also revealed that the distance of the front obstruction of 50 cm or more has no significant effect for the performance of the air conditioning unit. In addition, the side obstructions have the less significant effect than that of the front obstruction.

Experimental Verification of a Universal Accumulator Heat Exchanger Design Procedure Used to Achieve Liquid Overfeeding Effects in Small Air Conditioning Systems

1999 ◽  
Author(s):  
Craig W. Wood ◽  
Josua P. Meyer
Keyword(s):  
Heat Exchanger ◽  
Experimental Verification ◽  
Air Conditioning ◽  
Pressure Ratio ◽  
Design Procedure ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Direct Expansion ◽  
Air Conditioning System ◽  
Heat Exchanger Design

Abstract This study involves the experimental verification of a universal heat exchanger accumulator design procedure. A heat exchange accumulator was manufactured according to a mathematical model developed by the authors and installed into a small air conditioning system. Experimental results show that the addition of the heat exchanger accumulator results in a liquid overfeeding operation that replaces the previously utilized direct expansion operation. It provides an improved air conditioning system that has a 7.5% increase in coefficient of performance and a 4.4% increase in refrigerant mass flow rate. A pressure ratio reduction has a positive effect on the compressor performance and life span. Liquid overfeeding increases the cooling capacity of the system by 6.5%. When compared to direct expansion systems, this basic heat exchanger accumulator provides a reduction in cycling losses and power consumption, an increase in suction pressure and an improvement in isentropic compressor efficiency.

scholarly journals Air Conditioning System Performance of a City Hotel Appraised for Energy Use Efficiency

2021 ◽  
Vol 83 (1) ◽  
pp. 118-139
Author(s):  
I Made Rasta ◽  
I Nyoman Suamir
Keyword(s):  
Air Conditioning ◽  
Energy Use ◽  
Energy Performance ◽  
Efficiency Index ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Air Conditioning System ◽  
Use Efficiency ◽  
Ac Systems ◽  
System Selection

This paper presents results of a study on split air conditioning (AC) performance of a city hotel in Bali, Indonesia. The study applied a practical global approach to appraising the performance of existing AC systems and their installation in a city hotel. The results obtained indicate that improper AC system selection and installation potentially reduces their energy performance which include COP (coefficient of performance), EER (energy efficiency ratio), and SEI (system efficiency index). The finding also shows that improper system selection and installation has damaged 54 unit compressors of 90 AC systems installed in a particular building within three years’ period. Overall number of compressors that have been damaged in three years can reach 76 units accounted for about 23.1% of the total AC systems installed in the hotel. It is also found a reduction on AC system cooling capacity.

scholarly journals Effects of compressor speed and electronic expansion valve opening on the performance of R410a water chiller system

2020 ◽  
Vol 8 (1) ◽  
pp. 12-20
Author(s):  
Ahmed H. Al-Hassani ◽  
Alaa R. Al-Badri
Keyword(s):  
Electrical Energy ◽  
Cooling Capacity ◽  
System Stability ◽  
Coefficient Of Performance ◽  
Rotary Compressor ◽  
Variable Speed ◽  
Global Power ◽  
Expansion Valve ◽  
Valve Opening ◽  
Air Conditioning Systems

Refrigeration and air conditioning systems consume high rates of electrical energy of the total global power consumption. The major part of this energy is used by compressor which is the main equipment in vapor compression refrigeration systems. In this study, the performance of a variable speed chilled water refrigeration system with electronic expansion valve (EEV) is experimentally investigated. The system is composed of variable speed rotary compressor, water cooled condenser, electronic expansion valve, and evaporator with refrigerant R410a for one tone cooling capacity. The results showed that the EEV opening was related to the compressor speed at limits of refrigerant subcool and system stability to achieve better performance. Refrigerant superheats increased with closing the EEV at constant compressor speed. Moreover, the degree of superheat was inversely proportional to the compressor speed at constant EEV opening. The coefficient of performance (COP) was improved by about 2.2 to 4.0% by controlling the EEV at constant compressor speed. Increasing compressor speed from 1200 to 3600 rpm resulted in decreasing system COP from 5.2 to 2.35 due to the increase of the power consumed by compressor.

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