Irreversibility analysis of a two-evaporator vapour compression refrigeration system

Yataganbaba, Alptug; Kılıçarslan, Ali; Kurtbaş, İrfan

doi:10.1504/ijex.2015.072895

Cited by 6 publications

(5 citation statements)

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“…Concepts like exergy and irreversibility are introduced by the second law of thermodynamics. Irreversibilities are encountered in refrigeration cycles, in real conditions, because the heat transfers in evaporator and in condenser take place at finite temperature difference and the compression process in the compressor is an irreversible adiabatic processbecause of the frictions, [16]. The exergy analysis is a tool used to approach both the quantity and quality of the forms of energy in discussion, [17].…”

Section: First and Second Laws Based Analysismentioning

confidence: 99%

Effects of Vaporization Temperature and Sub Cooling Variation on the Performance of a Vapour Compression Refrigeration Cycle Working With R134a, Met on Newer Ships

Memet¹

2022

IJMMT

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R134a is a refrigerant met in several marine refrigeration applications, such as fishing vessels, passenger and cargo ships. In 2014, 26% of the international commercial fleet was using R134a. Although R134a shows a null Ozone Depletion Potential, it has a quite high Global Warming Potential (1300). R134a is a greenhouse gas and, even if it is present on newer ships, the future will be marked by its replacement with substitutes having low GWP. Still, because its GWP is less than 2500, R 134a will continue to be used. Due to the fact that vapour compression refrigeration systems are dominant on board the ships and knowing that these technologies are high energy consumers, analysing their performance in the contemporary energetic context, is imperious required. This paper presents a theoretical analysis of a single stage vapour compression cycle, working with R134a, based on the laws of thermodynamics. The analysis will reveal the influence of the evaporator temperature on the Coefficient of performance and on exergy efficiency, and also the influence of sub cooling on these two efficiency terms, on the refrigerant mass flow rate and compression rate. It was considered a variation of the evaporator temperature in the range (-40÷ -10)oC and of the sub cooling in the range (0÷10)oC. The increase of the evaporator temperature will contribute to a COP increment (50%) and an exergy efficiency decrease (34%). The sub cooling will lead to both COP and exergy efficiency increase (11%). Higher sub cooling degree will provide an increment in the refrigerant mass flow (18%) and a decrease of the compression rate (76%) meaning lower work consumption at the compressor.

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Section: First and Second Laws Based Analysismentioning

confidence: 99%

Effects of Vaporization Temperature and Sub Cooling Variation on the Performance of a Vapour Compression Refrigeration Cycle Working With R134a, Met on Newer Ships

Memet¹

2022

IJMMT

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“…Alternatively, the total flow exergy of moist air can be also calculated by the following (Equation 7) [4,8].…”

Section: Theoretical Analysismentioning

confidence: 99%

“…In the exergy balance, the difference between inlet and outlet exergy transfer rate by heat, work and mass equals to rate of the exergy destruction (Equation 1) [8,[10][11][12]. X heat,in +X mass,in -X work,out =X dest (1) The exergy transfer rate by heat, work and mass can be defined as follow (Equation 2-4):…”

Section: Theoretical Analysismentioning

confidence: 99%

“…They also demonstrated the effect of different fluids on the irreversibility values of the components by using MATLAB and EES software for exergy analysis of organic Rankine cycle. Yataganbaba et al [8] carried out irreversibility analysis to a two-evaporator vapor compression refrigeration cycle using R407C, R410A, R404A and R134a in order to investigate the effect of the evaporation and condensation temperatures on the exergy destruction of the system components. They emphasized that the exergy destruction rate of the components was affected by the changes in temperature of the evaporation and condensation.…”

Section: Introductionmentioning

confidence: 99%

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Irreversibility Analysis of a Minibus Air-Conditioner for Different Condensation Pressures

Karaçayli

Şimşek

2019

Çukurova Üniversitesi Mühendislik-Mimarlık Fakültesi Dergisi

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In this study, a minibus air conditioning (MAC) set using R134a was tested and evaluated in the Adana High Vocational School, Çukurova University. The condensation pressure was gradually increased from 650 kPa to 770 kPa. The indoor and outdoor temperatures were kept constant at 20 o C and 22 o C, respectively. The cooling capacity of the MAC is 6000 kcal/h at 35 ambient temperature. The MAC consists of four main elements; a compressor, a condenser, an expansion valve and an evaporator. The purpose of this study is to demonstrate how the irreversibility analysis is performed. For this aim, experiments were carried out for different condensation pressures at constant ambient temperature in order to determine the rates of the exergy transfer and the entropy generation within the all components and the MAC system. In addition to this, the rational exergy efficiency of the all components and the whole system were calculated. Increasing condensation pressure caused 8.3% increase in both the rate of entropy generation and the irreversibility rate for the whole system. Besides, the rational exergy efficiency of the whole system was approximately 24%.

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“…Thus, the occurring irreversibilities of each component and its amounts can be better determined for the considered system via using exergy analysis. [16,17]. Devecioglu et al [18] extensively studied the effect of the using plate type IHX on the liquid line of the system with R453a as an option to R22.…”

Section: Introductionmentioning

confidence: 99%

Exergetic Investigation of a R1234yf Automotive Air Conditioning System with Internal Heat Exchanger

Di̇rek

Mert

Yüksel

et al. 2018

International Journal of Thermodynamics

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This experimental study presents the exergetic investigation of an automotive air conditioning (AAC) system with the refrigerant R1234yf. The airconditioning system is based on the conventional mechanical compression refrigeration cycle. An internal heat exchanger (IHX) has been added to the system in order to provide performance enhancement. The influence of the IHX was investigated at different compressor speeds and air stream temperatures. Experimental measurements were controlled by using a data-acquisition system. The exergy destruction, exergy efficiency and the total exergy destruction per cooling capacity were calculated. The analysis results were compared with a baseline system which operates with the refrigerant R134a. Furthermore, an empirical correlation was proposed for the determination of the total exergy destruction per cooling capacity for various compressor speeds for evaluating the system performance. The exergetic efficiency of the system was improved by introducing IHX. Moreover, it was observed that the temperature rise in the air stream decreased the exergy efficiency and increased the total exergy destruction per cooling capacity.

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Irreversibility analysis of a two-evaporator vapour compression refrigeration system

Cited by 6 publications

References 0 publications

Effects of Vaporization Temperature and Sub Cooling Variation on the Performance of a Vapour Compression Refrigeration Cycle Working With R134a, Met on Newer Ships

Effects of Vaporization Temperature and Sub Cooling Variation on the Performance of a Vapour Compression Refrigeration Cycle Working With R134a, Met on Newer Ships

Irreversibility Analysis of a Minibus Air-Conditioner for Different Condensation Pressures

Exergetic Investigation of a R1234yf Automotive Air Conditioning System with Internal Heat Exchanger

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