A Study Initiated because of the Global Warming from R-134a

2013 ◽  
Vol 837 ◽  
pp. 751-756
Author(s):  
Feiza Memet ◽  
Daniela Elena Mitu
Keyword(s):  
Global Warming ◽  
Global Warming Potential ◽  
Ozone Depletion ◽  
Exergy Analysis ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
R 134A ◽  
Vapour Compression ◽  
Ozone Depletion Potential ◽  
Depletion Potential

Vapour compression cycles are commonly used in household refrigerators and also in many commercial and industrial refrigeration systems. R-134a is a working fluid widespread in this kind of systems. A chlorine free refrigerant such as R-134a has a disadvantage in the sense of its relatively high Global Warming Potential (GWP), although the specific Ozone Depletion Potential (ODP) is null. International concern over the relatively high global warming potential of R-134a, and other refrigerants belonging to the same family, will lead in the near future to the stop of their production and use. For this reason, the interest in finding of an environmental more benign substitute for this refrigerant is growing. In the meantime, the alternatives for R-134a should be as thermodynamically attractive as this chemical. In this study it is theoretically assessed the opportunity of using R-600a (isobutane) in the future environment friendly vapour compression refrigeration systems. Choosing of isobutane is explained by the fact that it is a naturally occurring refrigerant. During the thermodynamic analysis, R-134a and R-600a are evaluated for a range of evaporating temperatures starting with 25°C and finishing with 0°C. There are considered three levels of the condensing temperature: 30°C, 40°C, 50°C. For these two refrigerants are compared results regarding saturated vapour pressure, Coefficient of Performance, volumetric cooling capacity, compressor discharge temperature, refrigerant mass flow rate. Also, in the scope of future improvement of systems adopting R-600a as a refrigerant, it is performed an exergy analysis, which is able to reveal the hierarchy of inefficiencies in the system. The results obtained indicate that adopting of R-600a instead of R-134a in vapour compression refrigeration systems is a decision motivated not only by environment reasons, but also by thermodynamic arguments. Values for the Coefficient of Performance when using R-600a are slightly lower than when in use is R-134a, but isobutane offers better environmental requirements like zero Ozone Depletion Potential and very low Global Warming Potential. Exergy analysis developed for R-600a as a working fluid revealed that the most inefficient is the compressor. Better exergy efficiency can be obtained for higher values of the evaporating temperature.

Environment Friendly Mixed Refrigerant to Replace R-134a in a VCR System with Exergy Analysis

2014 ◽  
Vol 984-985 ◽  
pp. 1174-1179
Author(s):  
N. Austin ◽  
P.M. Diaz ◽  
D.S. Manoj Abraham ◽  
N. Kanthavelkumaran
Keyword(s):  
Global Warming ◽  
Global Warming Potential ◽  
Ozone Depletion ◽  
Exergy Analysis ◽  
Coefficient Of Performance ◽  
Refrigeration System ◽  
Evaporator Temperature ◽  
Environment Friendly ◽  
A Charge ◽  
Vapour Compression

Study on environment friendly mixed refrigerant to replace R134a in vapour compression refrigeration (VCR) System. The mixed refrigerants investigated are propane (R290), butane (R600), isobutene (R600a) and R134a. Even though the ozone depletion potentials of R134a relative to CFC-11 are very low; the global warming potentials are extremely high and also expensive. For this reason, the production and use of R134a will be terminated in the near future. Hydrocarbons are free from ozone depletion potential and have negligible global warming potential. The results showed that, mixed refrigerant with charge of 80 g satisfy the required freezer air temperature when R134a with a charge of 110 g is used as refrigerant. The actual COP of refrigerator using mixed refrigerant was almost nearer that of the system using R134a as refrigerant. The coefficient of performance of the vapour compression refrigeration system using mixed refrigerant MR-3 [R134a/R290/ R600a/ R600 (20/35/40/5)] is having very close value with R134a and the Global warming potential of MR-3 is negligible when compared with R134a. Hence the mixed refrigerant MR-3 is chosen as an environmental friendly alternate refrigerant to R134a. The exergy analysis of the vapour compression refrigeration system using R134a and all the above mixtures are investigated. The effect of evaporator temperature on exergy efficiency and exergy destruction ratio of the system are experimentally studied. The exergy defect in the compressor, condenser, expansion device and evaporator are also obtained. Key words: R134a, Mixed refrigerant, Chlorofluorocarbons, Propane, Butane, Isobutene, REFPROP, COP, ODP, GWP, Exergy, VCR System.

scholarly journals Exergy Analysis of VCR Systemwith Air-Cooled Condenser Working with Refrigerants R-134a & Hydrocarbon

2019 ◽  
Vol 9 (2) ◽  
pp. 2834-2839
Keyword(s):  
Global Warming ◽  
Global Warming Potential ◽  
Exergy Analysis ◽  
Exergy Destruction ◽  
Refrigeration System ◽  
Exergetic Efficiency ◽  
Domestic Refrigerator ◽  
R 134A ◽  
Main Components ◽  
Vapour Compression

This paper gives a detailed exergy analysis of a Vapour Compression Refrigeration System with the refrigerants R-134a and HC (mixture of R-290/R-600a). The aim of this paper is to find out the Exergy Analysis, Exergetic efficiency, Exergy Product, Exergy Destruction Ratio (EDR), Co-efficient of performance and 2nd law efficiency for the main components of the system such as compressor, condenser, evaporator and expansion device (throttle valve). The objective of this work is to find out an exergy analysis of the Hydrocarbon refrigerant as an alternative for R-134a. The VCRS performance using R134a will be evaluated for the effect of evaporating temperature on COP, exergetic efficiency and EDR and then compared with Hydrocarbon refrigerant. Due to prevention of GWP (Global Warming Potential), Hydrocarbon and R-134a are used as refrigerants to give better result for domestic refrigerator operation[8] .

scholarly journals Thermodynamic Analysis of Low GWP Refrigerant Mixtures in a Refrigerator as Replacement to R-134A

2019 ◽  
Vol 69 (4) ◽  
pp. 147-158
Author(s):  
Sk Mohammad Hasheer ◽  
Kolla Srinivas
Keyword(s):  
Global Warming ◽  
Global Warming Potential ◽  
Ozone Depletion ◽  
Global Climate ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Environmentally Sustainable ◽  
Discharge Temperature ◽  
R 134A ◽  
Volumetric Cooling

AbstractChlorofluorocarbons and hydro chlorofluorocarbons (HCFCs) are replaced by hydroflourocarbons (HFCs) which is not harmful to the ozone layer. However, few of HFCs have a relatively high global warming potential (GWP) and are subject to further examination due to growing concerns about global climate change. The goal now is to find the next generation of environmentally sustainable work fluids with an insignificant direct environmental impact in terms of ozone depletion and global warming potential. This document introduces the mixture of low-GWP refrigerants like R440A, R430A, R1234ze (E)/152a (50:50 by mass), R290/600a (40/60), R290/600(60/40), R290/600(50/50), ARM 42,ARM 42a and AC5 are used to replace R-134a in a domestic refrigeration system without doing any modifications to the system. The performance of the refrigerator was observed in terms of volumetric cooling capacity, blower discharge temperature, and coefficient of performance, refrigeration effect and energy consumption of a blower.

scholarly journals Comparative evaluation of a two-stage refrigeration system with flash intercooling using different refrigerants

2020 ◽  
Vol 24 (2 Part A) ◽  
pp. 815-830
Author(s):  
Ebru Mancuhan
Keyword(s):  
Global Warming ◽  
Low Temperature ◽  
Global Warming Potential ◽  
Ozone Depletion ◽  
Second Law ◽  
Refrigeration System ◽  
Intermediate Pressure ◽  
Ozone Depletion Potential ◽  
Depletion Potential ◽  
Temperature Applications

The aim of this study is to investigate the effect of low global warming potential refrigerants on the optimum intermediate pressure (POPT,int) and performance (COP) values of a refrigeration system with flash intercooling. For realize, the optimum operating parameters of system were determined in low temperature applications through a theoretical analysis according to the different refrigerants (R290, R404A, R407C, R507A, and R22). The theoretical modelling of system is done by optimizing the intermediate pressure at given evaporation (TE) and condensation (TC) temperatures for selected refrigerants. After optimization, the maximized values of COP and Second law efficiency are computed from the predicted values of POPT,int . The linear regression method is then used to derive three correlations of POPT,int , maximum values of COP and Second law efficiency according to TE and TC. Hence, the POPT,int values maximizing the system performance are found from various TE and TC values for each refrigerant. Due to calculations, increasing TE and TC cause the increase in POPT,int in low temperature applications. The R507A system has the highest POPT,int values and R22 system has the lowest POPT?int values. Although R22 system has slightly more efficient than R290 system, it is being phased out world?wide because of the risk of ozone depletion potential and global warming potential considerations. Therefore, it is important to evaluate the R22 replacement options. The R290 was discovered to have better performance than the R404A, R407C and R507A systems in terms of COPmax (1.81), global warming potential (11), and ozone depletion potential (0) when TE and TC are -35?C and 40?C.

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

2018 ◽  
Vol 197 ◽  
pp. 08013
Author(s):  
Enang Suma Arifianto ◽  
Ega Taqwali Berman ◽  
Mutaufiq Mutaufiq
Keyword(s):  
System Performance ◽  
Test Procedure ◽  
Cooling Capacity ◽  
Coefficient Of Performance ◽  
Working Fluid ◽  
Refrigeration Cycle ◽  
Air Conditioner ◽  
Air Conditioning System ◽  
Compressor Work ◽  
R 134A

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.

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