Thermodynamic analysis of transcritical CO2 refrigeration cycle integrated with thermoelectric subcooler and ejector

Liu, Xi; Fu, R.P.; Wang, Zhiqiang; Li, Lin; Sun, Zhixin; Li, Xuelai

doi:10.1016/j.enconman.2019.02.088

Cited by 54 publications

(13 citation statements)

References 45 publications

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“…The emergence of CO 2 is prominent among the researchers at Chinese research institutes; however, CO 2 systems started very late in the market. Researchers in China are doing research on CO 2 transcritical system, MAC system using CO 2, hybrid solar assisted CO 2 heat pump, CO 2 water heaters, absorption refrigeration with CO 2 power cycle, and so on.…”

Section: History Of Refrigerantsmentioning

confidence: 99%

Review of carbon dioxide (CO ₂ ) based heating and cooling technologies: Past, present, and future outlook

2019

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Summary Refrigerants bearing high global warming potential (GWP) and ozone depletion potential (ODP) were outlawed or facing time‐beared permission under the Montreal (1987), Kyoto (1997) protocols, F‐Gas law (2015), Paris Accord (2016), and recent Kigali Amendment to Montreal Protocol (2019). In order to modify followed by the paradigm shift of existing heating and cooling systems, American Society of Heating, Refrigeration, and Air‐Conditioning Engineers (ASHRAE) envisaged natural and synthetic refrigerants (Synrefs) are under investigation globally. Carbon dioxide (CO2) is a popular natural refrigerant (Natref) replacing Synrefs used in commercial heating, ventilation, air conditioning, and refrigeration (HVAC&R) systems globally. A rampant rise is observed in markets of Asia (Japan and China), North America (the United States and Canada), the Australian continent, and Africa (South Africa) by reaching 20 000 CO2‐stores around the globe. The European markets are leading the utilization of CO2 in the heat pump, and refrigeration, CO2 based markets estimate 14% of the total food retail stores (400 m2). Japan is the second leading market of CO2 heat pump and refrigeration with more than 10 200 CO2 condensing units. CO2 transcritical systems have a share of more than 10% in only European market (large stores); however, their share is less than 10% of total stores in other major markets of the world. New pump and compressor‐driven transcritical CO2 systems integrate ejectors, condensers, and booster systems to reduce energy consumptions, enhance efficiency, efficacy, and coefficient of performance. This article reports a critical review of the CO2 based heating, cooling, and refrigeration system and presents updated literature along with barriers and challenges on commercial use of Natref‐based heating and cooling applications worldwide.

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Section: History Of Refrigerantsmentioning

confidence: 99%

Review of carbon dioxide (CO ₂ ) based heating and cooling technologies: Past, present, and future outlook

2019

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“…Figure 1 a depicts the schematic diagram of the ETS cycle, which has been described in detail by Liu et al [ 33 ]. As indicated in Figure 1 b, the EMS cycle consists of a transcritical CO 2 ejector expansion cycle and a mechanical subcooling cycle, where they are connected by a subcooler.…”

Section: Cycle Description and Simulation Modelmentioning

confidence: 99%

“…Furthermore, the subcooling device can narrow down the working conditions of the ejector, which simplifies its design or regulation [ 23 ]. Liu et al [ 33 ] proposed the combination of a thermoelectric subcooling system and an ejector (ETS) to improve the energy efficiency of the transcritical CO 2 cycle. In addition, the ETS cycle exhibited prominent advantages in COP c and discharge pressure in the range studied.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic Analysis of Transcritical CO2 Ejector Expansion Refrigeration Cycle with Dedicated Mechanical Subcooling

Wang

Zheng

et al. 2019

Entropy

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: The new configuration of a transcritical CO2 ejector expansion refrigeration cycle combined with a dedicated mechanical subcooling cycle (EMS) is proposed. Three mass ratios of R32/R1234ze(Z) (0.4/0.6, 0.6/0.4, and 0.8/0.2) were selected as the refrigerants of the mechanical subcooling cycle (MS) to further explore the possibility of improving the EMS cycle’s performance. The thermodynamic performances of the new cycle were evaluated using energetic and exergetic methods and compared with those of the transcritical CO2 ejector expansion cycle integrated with a thermoelectric subcooling system (ETS). The results showed that the proposed cycle presents significant advantages over the ETS cycle in terms of the ejector performance and the system energetic and exergetic performances. Taking the EMS cycle using R32/R1234ze(Z) (0.6/0.4) as the MS refrigerant as an example, the improvements in the coefficient of performance and system exergy efficiency were able to reach up to 10.27% and 15.56%, respectively, at an environmental temperature of 35 C and evaporation temperature of −5 C. Additionally, the advantages of the EMS cycle were more pronounced at higher environmental temperatures.

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“…In CO2 refrigeration system, Bellos and Tzivanidis [8], reported the performance of the system upto 75% by the use of mechanical subcooling system, over the basic configuration. Use of ejector and thermoelectric subcooling enhance the performance upto 40% [9]. Internal heat exchanger for subcooling improves the COP by 12 and 25% by using thermoelectric subcooling for specific operating conditions [10] Hojjat Mohammadi [11] studied various configurations of the CO2 refrigeration system coupled with different absorption chillers to produce refrigeration at different temperature levels from -80°C to -30°C with an increase of COP upto 200% in few cases.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic Analysis of a Combined Single Effect Vapour Absorption System and tc-CO2 Compression Refrigeration System

Verma

Kaushik

Tyagi

2021

HighTech. Innov. J.

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Transcritical CO2 refrigeration system is coupled with the single effect vapour absorption with LiBr-water as a working pair having an objective to enhance the performance of low temperature transcritical refrigeration system while using natural working pair and to reduce the electricity consumption to produce low temperature refrigeration. The high grade waste heat rejected in the gas cooler of tc-CO2 compression refrigeration system (TCRS) is utilized to run the single effect vapour absorption system (SEVAR) to enhance the energy efficiency of the system. The gas cooler in the transcritical CO2 system is having heat energy at high temperature and pressure, which is utilized to run the vapour absorption system, while the other refrigerant heat exchanger provides subcooling to further enhance the performance. The combined cycle can provide refrigeration temperature at different levels, to use it for different applications. Energetic and exergetic analysis have been done to analyze the combined system to compute the performance parameters and the irreversibilities occurring in different components to further increase the performance. The combined system is optimized for various heat rejection and refrigeration temperatures. The COP of the combined system has been enhanced by to 24.88% while the enhancement in exergetic efficiency (ηex) is observed as 10.14% respectively over tradition transcritical CO2 compression refrigeration system, with -10°C as an evaporation (TCRS cooling) temperature and exit temperature of gas cooler T4 being 40°C. Doi: 10.28991/HIJ-2021-02-02-02 Full Text: PDF

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Thermodynamic analysis of transcritical CO2 refrigeration cycle integrated with thermoelectric subcooler and ejector

Cited by 54 publications

References 45 publications

Review of carbon dioxide (CO ₂ ) based heating and cooling technologies: Past, present, and future outlook

Review of carbon dioxide (CO ₂ ) based heating and cooling technologies: Past, present, and future outlook

Thermodynamic Analysis of Transcritical CO2 Ejector Expansion Refrigeration Cycle with Dedicated Mechanical Subcooling

Thermodynamic Analysis of a Combined Single Effect Vapour Absorption System and tc-CO2 Compression Refrigeration System

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Thermodynamic analysis of transcritical CO2 refrigeration cycle integrated with thermoelectric subcooler and ejector

Cited by 54 publications

References 45 publications

Review of carbon dioxide (CO 2 ) based heating and cooling technologies: Past, present, and future outlook

Review of carbon dioxide (CO 2 ) based heating and cooling technologies: Past, present, and future outlook

Thermodynamic Analysis of Transcritical CO2 Ejector Expansion Refrigeration Cycle with Dedicated Mechanical Subcooling

Thermodynamic Analysis of a Combined Single Effect Vapour Absorption System and tc-CO2 Compression Refrigeration System

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Review of carbon dioxide (CO ₂ ) based heating and cooling technologies: Past, present, and future outlook

Review of carbon dioxide (CO ₂ ) based heating and cooling technologies: Past, present, and future outlook