Numerical simulation and experimental validation of internal heat exchanger influence on CO2 trans-critical cycle performance

Rigola, Joaquim; Ablanque, Nicolás; Segarra, Carlos David Pérez; Oliva, A.

doi:10.1016/j.ijrefrig.2009.12.030

Cited by 66 publications

(22 citation statements)

References 6 publications

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“…The more efficient the IHE, the higher the system COP. This inclination of the throttle valve cycle is consistent with the published literatures [10][11][12][13][14][15]. The similar trend is observed for the expander cycle with ηexp,is = 0.3.…”

Section: Resultssupporting

confidence: 91%

“…Torrella et al [14] experimentally found that the IHE addition in transcritical CO2 refrigeration system provides a maximum increase in cooling capacity of 12%, an increase of the cycle COP of up to 12% and a maximum increase of the discharge temperature of 10 °C at −15 °C evaporating temperature. Through experimental and theoretical studies, Rigola et al [15] found that the IHE addition increases cycle COP by about 20% at a gas cooler outlet temperature of 35 °C. Zhang et al [16] found that the COP is slightly decreased by an IHE in a CO2 subcritical refrigeration cycle.…”

Section: Introductionmentioning

confidence: 99%

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Effect of an Internal Heat Exchanger on Performance of the Transcritical Carbon Dioxide Refrigeration Cycle with an Expander

Zhang

Tian

Chen

et al. 2014

Entropy

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Abstract:The effect of the internal heat exchanger (IHE) on the performance of the transcritical carbon dioxide refrigeration cycle with an expander is analyzed theoretically on the basis of the first and second laws of thermodynamics. The possible parameters affecting system efficiency such as heat rejection pressure, gas cooler outlet temperature, evaporating temperature, expander isentropic efficiency and IHE effectiveness are investigated. It is found that the IHE addition in the carbon dioxide refrigeration cycle with an expander increases the specific cooling capacity and compression work, and decreases the optimum heat rejection pressure and the expander output power. An IHE addition does not always improve the system performance in the refrigeration cycle with an expander. The throttle valve cycle with IHE provides a 5.6% to 17% increase in maximum COP compared to that of the basic cycle. For the ideal expander cycle with IHE, the maximum COP is approximately 12.3% to 16.1% lower than the maximum COP of the cycle without IHE. Whether the energy efficiency of the cycle by IHE can be improved depends on the isentropic efficiency level of the expander. The use of IHE is only applicable in the cases of lower expander isentropic efficiencies or higher gas cooler exit temperatures for the refrigeration cycle with an expander from the view of energy efficiency. OPEN ACCESSEntropy 2014, 16 5920

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Section: Resultssupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Effect of an Internal Heat Exchanger on Performance of the Transcritical Carbon Dioxide Refrigeration Cycle with an Expander

Zhang

Tian

Chen

et al. 2014

Entropy

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“…Firstly, they concerned about gas cooler/condenser optimization [13][14][15][16], which obtained that the gas cooler design can effect significantly in supercritical condition. Secondly, improvement used application of Internal Heat Exchanger (IHX) [3], [6], [17]. Aprea and Maiorino [3], Torrella et al [6] conducted experiments investigating the influence of the internal heat exchanger (IHX) on carbon dioxide supercritical refrigerating plants and the performance of the system.…”

Section: Introductionmentioning

confidence: 99%

“…It was confirmed that the use of the IHX increases the COP of the system by 10%. In addition, the use of the IHX was associated with an increase in compressor discharge temperature, reaching increments up to 10 o C at the evaporating temperature of 15 o C. Moreover, Rigola et al [17] added that there are specific conditions to reach maximum performance of a CO 2 supercritical refrigeration system using an internal heat exchanger. The first condition, when the ambient temperature of 35 o C and the optimal discharge pressure is between 95 and 100 bar, the COP increases by 20%.…”

Section: Introductionmentioning

confidence: 99%

Performance Analysis of Transcritical Co2 Refrigeration System for Supermarket Application

Santosa¹

2018

GEOMATE

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Environmental issues becomes a priority on the refrigeration system development. The main issues are global warming and ozone depletion which are emitted from the conventional refrigeration system. One of the natural and clean refrigerants is Carbon dioxide (CO 2 ). CO 2 refrigeration system however still has low performance when operating at high ambient temperature. This study aim is to investigate the performance of CO 2 transcritical refrigeration system in high outdoor temperature. The research was carried out by theoretical study and numerical analysis of the refrigeration system using the EES (Engineering Equation Solver) program. Data input and simulation validation were obtained from experimental and secondary data. The result showed that the coefficient of performance (COP) decreased gradually with the outdoor temperature variation increasing. With temperature input increases between 25 o C -45 o C, the performance (indicated by overall COP) decreased by 3.0 %. These results will be significantly important for a preliminary reference to improve the CO 2 refrigeration system design in hot climate temperature application.

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“…It is an important factor to achieve high system performance; therefore some research works focusing on CO2 trans-critical systems with IHX have been reported [3][4][5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Experimental and Numerical Design and Optimization of a Counter-Flow Heat Exchanger

Bahrami

Rahimian

2018

MATEC Web Conf.

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Abstract.A new inexpensive counter-flow heat exchanger has been designed and optimized for a vapor-compression cooling system in this research. The main aim is to experimentally and numerically evaluate the effect of an internal heat exchanger (IHX) adaptation in an automotive air conditioning system. In this new design of IHX, the highpressure liquid passes through the central channel and the low-pressure vapor flows in several parallel channels in the opposite direction. The experimental set-up has been made up of original components of the air conditioning system of a medium sedan car, specially designed and built to analyze vehicle A/C equipment under real operating conditions. The results show that this compact IHX may achieve up to 10% of the evaporator capacity while low pressure drop will be imposed on this refrigeration cycle. Also, they confirm considerable decrease of compressor power consumption (CPC), which is intensified at higher evaporator air flow. A significant improvement of the coefficient of performance (COP) is achieved with the IHX employment too. The influence of operating conditions has been also discussed in this paper. Finally, numerical analyses have been briefly presented, which bring more details of the flow behavior and heat transfer phenomena, and help to determine the optimal arrangement of channels.

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Numerical simulation and experimental validation of internal heat exchanger influence on CO2 trans-critical cycle performance

Cited by 66 publications

References 6 publications

Effect of an Internal Heat Exchanger on Performance of the Transcritical Carbon Dioxide Refrigeration Cycle with an Expander

Effect of an Internal Heat Exchanger on Performance of the Transcritical Carbon Dioxide Refrigeration Cycle with an Expander

Performance Analysis of Transcritical Co2 Refrigeration System for Supermarket Application

Experimental and Numerical Design and Optimization of a Counter-Flow Heat Exchanger

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