Thermodynamic analysis of a novel ejector expansion transcritical CO 2 /N 2 O cascade refrigeration (NEETCR) system for cooling applications at low temperatures

Megdouli, K.; Ejemni, N.; Nahdi, E.; Mhimid, Abdallah; Kairouani, Lakdar

doi:10.1016/j.energy.2017.04.073

Cited by 39 publications

(6 citation statements)

References 34 publications

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“…However, better turbine conditions are required to use this in the future to improve the efficiency of the system. A theoretical study was carried out by Megdouli et al for enhancing the energy and performance of the cascade refrigeration system. The performance of CO 2 /N 2 O cascade refrigeration (NEETCR) system can be improved by using the rejected heat at gas cooler to drive a Rankine cycle.…”

Section: Solar Thermal Heating and Coolingmentioning

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: Solar Thermal Heating and Coolingmentioning

confidence: 99%

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

2019

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“…Sanchez et al [20] studied an R134a/CO 2 cascade refrigeration system and they stated that the direct cascade system is more efficient than the indirect system with a deviation of about 11%. Megdouli et al [21] examined a cascade system with CO 2 /N 2 O and ejectors, and they concluded that these refrigerants have similar performances in the cascade systems because of their similar critical temperatures. Moreover, the use of NH 3 /CO 2 cascade systems is common in the literature [22].…”

Section: Of 27mentioning

confidence: 99%

CO2 Transcritical Refrigeration Cycle with Dedicated Subcooling: Mechanical Compression vs. Absorption Chiller

Bellos

Tzivanidis

2019

Applied Sciences

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The objective of this paper is the comparison of two dedicated subcooling methods, after the gas cooler, in a CO2 transcritical refrigeration system. The use of vapor compression refrigeration with R134a for subcooling is the first method, and the second is the use of an absorption chiller that operates with a LiBr-H2O working pair. The examined systems are compared energetically and exegetically with the reference transcritical CO2 refrigeration cycle without subcooling. The analysis is conducted for different operating scenarios and in every case, the system is optimized by selecting the proper temperature and pressure levels. The analysis is performed with a developed and validated model in Engineering Equation Solver. According to the final results, the use of the absorption chiller is able to decrease the system electricity consumption by about 54% compared to the simple transcritical cycle, while the decrease with the mechanical subcooling is 41%. Both systems with dedicated subcooling are found to have an important increase in the system exergy performance compared to the simple transcritical cycle. However, the system with the mechanical subcooling is found to be the best choice exegetically, with a small difference from the system with the absorption chiller.

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“…This new type of eject-expansion cascade system was a valuable refrigeration system from the theory and engineering point of view. They further investigated the novel ejector expansion transcritical cascade refrigeration system using proposed natural refrigerants CO 2 /N 2 O [24]. Mofrad et al investigated the CO 2 /CO 2 cascade refrigeration system with heat recovery and the expansion valve in HTC and LTC are all replaced by ejector to enhance the system performance [25].…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic Analysis of an NH3/CO2 Cascade Refrigeration System with Subcooling in the Low-Temperature Circuit Utilizing the Expansion Work

Yang

Chen

Chi

et al. 2023

International Journal of Energy Research

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NH3/CO2 cascade refrigeration system is recognized one of the most promising technologies in low-temperature application. In this paper, a NH3/CO2 cascade refrigeration system with subcooling in low-temperature circuit driven by recovery expansion work has been proposed. The aim of this study is to investigate the proposed cascade refrigeration system compared with conventional cascade refrigeration system. Mathematical models based on energy conservation and exergy balance are established. The selection of different refrigerants in auxiliary subcooling system is discussed. The effects of operating parameters such as the condensation temperature of the low-temperature circuit, evaporation temperature, and expander efficiency on system performance are evaluated. The results show that the coefficient of performance and exergy efficiency of the proposed system are about 7.56% and 7.98% higher than that of conventional cascade refrigeration system. The discharge temperature of NH3 compressor can be significantly reduced by 18.33%. The isentropic efficiency of the expander has a large impact on the system performance.

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Thermodynamic analysis of a novel ejector expansion transcritical CO 2 /N 2 O cascade refrigeration (NEETCR) system for cooling applications at low temperatures

Cited by 39 publications

References 34 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

CO2 Transcritical Refrigeration Cycle with Dedicated Subcooling: Mechanical Compression vs. Absorption Chiller

Thermodynamic Analysis of an NH3/CO2 Cascade Refrigeration System with Subcooling in the Low-Temperature Circuit Utilizing the Expansion Work

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Thermodynamic analysis of a novel ejector expansion transcritical CO 2 /N 2 O cascade refrigeration (NEETCR) system for cooling applications at low temperatures

Cited by 39 publications

References 34 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

CO2 Transcritical Refrigeration Cycle with Dedicated Subcooling: Mechanical Compression vs. Absorption Chiller

Thermodynamic Analysis of an NH3/CO2 Cascade Refrigeration System with Subcooling in the Low-Temperature Circuit Utilizing the Expansion Work

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Product

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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