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] .

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.

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.

Exergy Analysis of a Solar-Driven Dual Parallel-Connected Ejector Refrigeration System

2016 ◽  
Vol 839 ◽  
pp. 100-106
Author(s):  
Yahya Gaafar Abdella Mohammed ◽  
Tawat Suriwong ◽  
Sakda Somkun ◽  
Timeyo Mkamanga Maroyi
Keyword(s):  
Solar Collector ◽  
Exergy Analysis ◽  
Operating Conditions ◽  
Coefficient Of Performance ◽  
Saturated Steam ◽  
Working Fluid ◽  
Electric Heater ◽  
Exergy Destruction ◽  
Refrigeration System ◽  
Exergetic Efficiency

Nowadays, developing solar cooling technologies, especially ejector refrigeration system, has become preferable to scientific researchers. Exergy analysis is a technique in which the basis of evaluation of thermodynamic losses follows the second law rather than the first law of thermodynamics. An experimental exergy analysis of a solar-driven dual parallel-connected ejector (DPE) refrigeration system was conducted using water as working fluid. Saturated steam with 2 bar and 120oC was provided by heat–pipe evacuated tube solar collector with an assistant of an electric heater. The saturated stream was used as a motive flow for the ejectors. The exergy destruction and exergetic efficiency of the main components of the DPE refrigeration system were determined and compared with those when using a single ejector (SE) under same operating conditions. It was found that the most irreversibilities of both systems occurred at the solar collector, electric boiler and ejectors, respectively. Also, the total irreversibility (Exergy destruction) of the system when using DPE was lower than using a SE. In additions, the exergetic efficiency of the ejector, evaporator, and overall system when using DPE were increased by 21%, 10%, and 27%, respectively. The system thermal ratio (STR) and coefficient of performance (COP) of the system using DPE compared with SE were increased by 20% and 23%, respectively.

Thermodynamic Analysis of R134a-R23 Cascade Refrigeration System

2015 ◽  
Vol 787 ◽  
pp. 117-123
Author(s):  
P.L. Rupesh ◽  
J.M. Babu ◽  
R. Mariappan
Keyword(s):  
Regression Analysis ◽  
Thermodynamic Analysis ◽  
Minimum Temperature ◽  
Exergy Analysis ◽  
Operating Parameters ◽  
Exergy Destruction ◽  
Refrigeration System ◽  
Cascade Refrigeration System ◽  
R 134A ◽  
Cascade Refrigeration

The present work deals with thermodynamic analysis of a R-134a/R-23 cascade refrigeration system to evaluate the maximum COP and the minimum temperature difference (DT) corresponding to , by considering different operating parameters. The operating parameters includes: the condensing () and evaporating temperature () of R-134a and the condensing () and evaporating temperature () of R-23. A computational model has been developed for the considered system to evaluate the and DT corresponding to based on the thermodynamic principles. A mutilinear regression analysis has been carried out to evaluate two correlations for calculating and minimum DT considering the above operating parameters. The exergy analysis of the system is also performed to determine the irreversibility losses of the system as well as for the components. It has been found that the total exergy destruction rate of the system is lower at minimum .

scholarly journals New HFC/HFO Blends as Refrigerants for the Vapor-Compression Refrigeration System (VCRS)

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 946
Author(s):  
Bartosz Gil ◽  
Anna Szczepanowska ◽  
Sabina Rosiek
Keyword(s):  
Global Warming ◽  
Global Warming Potential ◽  
Mass Fraction ◽  
Vapor Compression ◽  
Refrigeration System ◽  
Operational Parameters ◽  
Vapor Compression Refrigeration ◽  
Low Global Warming Potential ◽  
Triangular Design

In this work, which is related to the current European Parliament Regulation on restrictions affecting refrigeration, four new three-component refrigerants have been proposed; all were created using low Global Warming Potential(GWP) synthetic and natural refrigerants. The considered mixtures consisted of R32, R41, R161, R152a, R1234ze (E), R1234yf, R1243zf, and RE170. These mixtures were theoretically tested with a 10% step in mass fraction using a triangular design. The analysis covered two theoretical cooling cycles at evaporating temperatures of 0 and −30 °C, and a 30 °C constant condensing temperature. The final stage of the work was the determination of the best mixture compositions by thermodynamic and operational parameters. R1234yf–R152a–RE170 with a weight share of 0.1/0.5/0.4 was determined to be the optimal mixture for potentially replacing the existing refrigerants.

Exergy Analysis of Part Flow Evaporative Gas Turbine Cycles: Part 2 — Results and Discussion

2002 ◽  
Author(s):  
Maria Jonsson ◽  
Jinyue Yan
Keyword(s):  
Gas Turbine ◽  
Heat Recovery ◽  
Exergy Analysis ◽  
Compressed Air ◽  
Cycle Performance ◽  
Exergy Destruction ◽  
Exergetic Efficiency ◽  
Recovery System ◽  
Heat Recovery System ◽  
Flow Case

This paper is the second part of a two-part paper. The first part contains an introduction to the evaporative gas turbine (EvGT) cycle and the methods used in the study. The second part contains the results, discussion, and conclusions. In this study, exergy analysis of EvGT cycles with part flow humidification based on the industrial GTX100 and the aeroderivative Trent has been performed. In part flow EvGT cycles, only a fraction of the compressed air is passed through the humidification system. The paper presents and analyzes the exergetic efficiencies of the components of both gas turbine cycles. The highest cycle exergetic efficiencies were found for the full flow case for the GTX100 cycles and for the 20% part flow case for the Trent cycles. The largest exergy destruction occurs in the combustor, and the exergetic efficiency of this component has a large influence on the overall cycle performance. The exergy destruction of the heat recovery system is low.

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