Progress in ejector-expansion vapor compression refrigeration and heat pump systems

Zhang, Zhenying; Xu, Feng; Tian, Dingzhu; Yang, Jianjun; Chang, Li

doi:10.1016/j.enconman.2020.112529

Cited by 82 publications

(12 citation statements)

References 169 publications

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“…The results obtained in this study are in concordance with other previous. Zhang et al (2020) illustrate that ejector configurations without IHX provide an experimental COP improvement up to 20% for subcritical systems. Moreover, they suggested that the performance of the ejector configuration can be further improved with the addition of IHX, which is in concordance with the results obtained in this study.…”

Section: Multi-objective Comparisonmentioning

confidence: 90%

“…3. Although there are several ejector configurations (Zhang et al, 2020), it has been selected the configuration with an IHX to maximize the discharge temperature. Moreover, this configuration requires the addition of a liquid receiver to ensure proper operation.…”

Section: Ejector Cyclementioning

confidence: 99%

“…Besides, Luo and Zou (2019) found more benefits in terms of heating production with several ejector combinations. The review paper of Zhang et al (2020) showed the operational and energetic benefits of ejector-expansion technology in vapor compression systems. Nevertheless, most of the theoretical studies that consider ejectors for refrigerant applications and using CO 2 as working fluid (Pérez-García et al, 2016;Rodríguez-Muñoz et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Theoretical performance evaluation of ejector and economizer with parallel compression configurations in high temperature heat pumps

Mateu-Royo

Navarro-Esbrí

Barragán-Cervera

2020

International Journal of Refrigeration

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Section: Multi-objective Comparisonmentioning

confidence: 90%

Section: Ejector Cyclementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Theoretical performance evaluation of ejector and economizer with parallel compression configurations in high temperature heat pumps

Mateu-Royo

Navarro-Esbrí

Barragán-Cervera

2020

International Journal of Refrigeration

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“…The ejector cycle is not studied in the present investigation since it is mainly used for cooling applications and near steady‐state operation. [ 13 ]…”

Section: Numerical Modelingmentioning

confidence: 99%

Investigation of the Interactions between Refrigerant, Flowsheet, and Compressor in Residential Heat Pumps

et al. 2023

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The refrigerant used in heat pumps significantly influences the overall system performance. However, selecting a proper refrigerant is no trivial matter due to the heat pumps’ sensitivity to the selected flowsheet, components, and operating conditions. Herein, a holistic approach is used that covers all these interdependencies simultaneously considering the flowsheet, fluid‐dependent compressor efficiencies, and the operating point. Six low global warming potential (GWP<150) refrigerants are investigated, which include pure fluids, azeotropic mixtures, and zeotropic mixtures from different substance groups. For four flowsheets, the seasonal coefficient of performance (SCOP) by EN 14825 is calculated and serves as the assessment metric. The case study is based on typical conditions of residential heat pumps. The results show that the SCOPs substantially differ depending on the refrigerant and the flowsheet (reaching from 3.8 to 4.6). Differences in the performance of refrigerants for an equal flowsheet are mainly driven by compressor efficiency. However, these differences can be overcome by adjusting the flowsheet. In particular, when an internal heat exchanger is added, the refrigerant ranking is substantially changed. It is shown that R436A, which is inferior to R290 for the basic cycle, benefits more from an internal heat exchanger and reaches a competitive SCOP than R290.

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“…A different layout can be adopted by including an ejector in the thermodynamic cycle, which allows the decrease in the compression work by reducing the throttling losses and the liquid overfeeding and lifting the compressor inlet pressure [15]. The ejector is a flow device with two intake ports and one discharge port.…”

Section: Introductionmentioning

confidence: 99%

A Novel Ground-Source Heat Pump with R744 and R1234ze as Refrigerants

et al. 2020

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The energy-saving potential of heat pump technology is widely recognized in the building sector. In retrofit applications, especially in old and historic buildings, it may be difficult to replace the existing distribution and high-temperature emission systems. Often, historical buildings, especially the listed ones, cannot be thermally insulated; this leads to high temperatures of the heat carrier fluid for heating. In these cases, the main limits are related, on the one hand, to the reaching of the required temperatures, and on the other hand, to the obtaining of good performance even at high temperatures. To address these problems, a suitable solution can be a two-stage heat pump. In this work, a novel concept of a two-stage heat pump is proposed, based on a transcritical cycle that uses the natural fluid R744 (carbon dioxide) with an ejector system. The second refrigerant present in the heat pump and used for the high-temperature stage is the R1234ze, which is an HFO (hydrofluoro-olefin) fluid. This work aims to present the effective energy performance based on real data obtained in operating conditions in a monitoring campaign. The heat pump prototype used in this application is part of the H2020 Cheap-GSHP project, which was concluded in 2019.

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Progress in ejector-expansion vapor compression refrigeration and heat pump systems

Cited by 82 publications

References 169 publications

Theoretical performance evaluation of ejector and economizer with parallel compression configurations in high temperature heat pumps

Theoretical performance evaluation of ejector and economizer with parallel compression configurations in high temperature heat pumps

Investigation of the Interactions between Refrigerant, Flowsheet, and Compressor in Residential Heat Pumps

A Novel Ground-Source Heat Pump with R744 and R1234ze as Refrigerants

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