Theoretical evaluation of trans-critical CO2 systems in supermarket refrigeration. Part I: Modeling, simulation and optimization of two system solutions

Sawalha, Samer

doi:10.1016/j.ijrefrig.2007.05.017

Cited by 76 publications

(36 citation statements)

References 6 publications

(15 reference statements)

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“…The advantage is bigger at lower ambient temperature side. This means annual efficiency of CO 2 -CO 2 cascade system is around 20% better than typical R404A refrigeration system, because average ambient temperature is below 20 o C at most of city around the world [2]. Figure 11 & 12 are calculated COP that were given from approximate expression of COP in Figure 10.…”

Section: Effect Of Co 2 -Co 2 Cascade Systemmentioning

confidence: 99%

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Improvement of Energy Efficiency by Cascade System with CO2 Refrigerant

Yamaguchi¹

2017

MOJCE

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The condition for calculation and compressor efficiency was quoted from previous paper [1]. The system efficiency of cascade refrigeration system is shown by formula (1) to (5). The total rate AbstractGlobal warming is commonly issue in worldwide. From point of global warming point of view, alternate HFC refrigerant to natural refrigerant is one of the means to reduce global warming gas which is used to refrigeration system in food store such as supermarket and convenience store. Carbon dioxide (hereinafter CO 2 ) is one of the dominant candidates as low Global Warming Potential (hereinafter GWP) refrigerant. However CO 2 refrigerant has lower efficiency for refrigeration because of low critical temperature. Also CO 2 refrigerant has higher system pressure than HFC refrigerant. Therefore typical cascade refrigeration system is equipped HFC refrigerant in higher temperature cycle. This report indicate the potential of CO 2 -CO 2 cascade system even CO 2 refrigerant itself has lower efficiency than HFC refrigerant. And this report shows optimization of discharge pressure, suction pressure and internal heat exchanger are important to get better performance.Keywords: CO 2 ; Carbon dioxide; Coefficient of performance; Cascade

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Section: Effect Of Co 2 -Co 2 Cascade Systemmentioning

confidence: 99%

“…The configuration of IHX depends on operating condition [2]. However the configuration of IHX is not changeable.…”

Section: Effect Of Internal Heat Exchangermentioning

confidence: 99%

Improvement of Energy Efficiency by Cascade System with CO2 Refrigerant

Yamaguchi¹

2017

MOJCE

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“…In accordance with Cavallini and Zilio [34], an optimal high pressure as a function of the gas cooler outlet temperature has to be identified in order to maximize the COP of a CO2 machine operating in transcritical running modes. An optimization procedure similar to that implemented by Sawalha [35] was applied to the investigated system. As far as its intermediate pressure was concerned, it was set to 40 bar [31].…”

Section: Investigated Solutionmentioning

confidence: 99%

Thermodynamic Performance Assessment of a CO2 Supermarket Refrigeration System with Auxiliary Compression Economization by using Advanced Exergy Analysis

Gullo

Hafner

2017

International Journal of Thermodynamics

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Supermarkets are currently one of the most vital service facilities, whose number of installations is ever-growing in both developed and developing countries. On the other hand, these applications feature a copious indirect contribution to the ongoing climate change, as well as a massive use of potent greenhouse gases. In an attempt to promote climatefriendlier technologies in commercial refrigeration sector, "CO2 only" (transcritical CO2 or pure CO2) refrigeration systems have become the mainstream of new food retails worldwide. In particular, in the last few years parallel (or auxiliary) compression has taken root in food retails as a means to enhance the energy efficiency of pure CO2 units. The thermodynamic performance of such a promising solution can be suitably assessed with the aid of the advanced exergy analysis. The results obtained at the design outdoor temperature of 40 °C showed that the main compressor has the highest priority of enhancement, whereas the high-pressure expansion valve needs to be replaced with a device for expansion work recovery. Also, close attention had to be paid to both the gas cooler and the auxiliary compressor. The former can be improved mainly by enhancing the other components, whereas the irreversibilities related to the latter can be decreased by improving both the compressor itself and the remaining components. Finally, the implemented sensitivity analysis revealed that the improvement in the efficiency of the main compressor should be seriously considered on the part of the manufacturers.

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“…Authors of article [3] received, as a result of optimization of different supercritical CO 2 refrigeration systems of a supermarket, graphs of dependence of their COP on the values of ambient temperature. Based on this, they selected the system that possesses the largest COP in the examined temperature range of surrounding air.…”

Section: K U Z N E T S O Vmentioning

confidence: 99%

Thermoeconomic optimization of supercritical refrigeration system with the refrigerant R744 (CO2)

Kuznetsov

Харлампиди

Tarasova

et al. 2016

EEJET

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Розроблена термоекономічна модель холо-дильної установки, що працює по надкритич-ному циклу CO 2 у якості холодагенту. Модель побудована для установки типу "повітря -повітря" і дозволяє при оптимізації конструк-ції і виборі економічних режимів роботи одно-часно враховувати як термодинамічні, так і економічні параметри. Приведені результати оптимізації, що забезпечують умови досяг-нення мінімального рівня приведених витрат Ключові слова: термоекономічна модель, надкритичний цикл, ексергія, приведені ви-трати Разработана термоэкономическая модель холодильной установки, работающей по сверхкритическому циклу CO 2 в качестве хла-дагента. Модель построена для установки типа «воздух -воздух» и позволяет при опти-мизации конструкции и выборе экономичных режимов работы одновременно учитывать как термодинамические, так и экономические параметры. Приведены результаты оптими-зации, обеспечивающие условия достижения минимального уровня приведенных затрат Ключевые слова: термоэкономическая мо-дель, сверхкритический цикл, эксергия, приве-денные затраты UDC 621.577;621.564

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Theoretical evaluation of trans-critical CO2 systems in supermarket refrigeration. Part I: Modeling, simulation and optimization of two system solutions

Cited by 76 publications

References 6 publications

Improvement of Energy Efficiency by Cascade System with CO2 Refrigerant

Improvement of Energy Efficiency by Cascade System with CO2 Refrigerant

Thermodynamic Performance Assessment of a CO2 Supermarket Refrigeration System with Auxiliary Compression Economization by using Advanced Exergy Analysis

Thermoeconomic optimization of supercritical refrigeration system with the refrigerant R744 (CO2)

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