HFO refrigerants: A review of present status and future prospects.

Nair, Vipin

doi:10.1016/j.ijrefrig.2020.10.039

Cited by 119 publications

(34 citation statements)

References 116 publications

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“…While R600a may be considered the preferred working fluid based on the ODP and GWP criteria in this study, it is classified as highly flammable, which has raised safety concerns for residential air conditioning applications [20,31,41,42]. In addition, although new HFOs with near-zero or zero ODP and GWP appear to be, overall, less flammable than hydrocarbons [43], they are currently up to eight times more expensive than HFCs [41] and, consequently, may not be affordable in certain developing economies with a high demand of air conditioning in hot climates.…”

Section: Solar-assisted Ejector Space Cooling Systemmentioning

confidence: 98%

Thermodynamic Performance Investigation of a Small-Scale Solar Compression-Assisted Multi-Ejector Indoor Air Conditioning System for Hot Climate Conditions

Eveloy

Alkendi

2021

Energies

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In year-round hot climatic conditions, conventional air conditioning systems consume significant amounts of electricity primarily generated by conventional power plants. A compression-assisted, multi-ejector space cooling system driven by low-grade solar thermal energy is investigated in terms of energy and exergy performance, using a real gas property-based ejector model for a 36 kW-scale air conditioning application, exposed to annually high outdoor temperatures (i.e., up to 42 °C), for four working fluids (R11, R141b, R245fa, R600a). Using R245fa, the multi-ejector system effectively triples the operating condenser temperature range of a single ejector system to cover the range of annual outdoor conditions, while compression boosting reduces the generator heat input requirement and improves the overall refrigeration coefficient of performance (COP) by factors of ~3–8 at medium- to high-bound condenser temperatures, relative to simple ejector cycles. The system solar fraction varies from ~0.2 to 0.9 in summer and winter, respectively, with annual average mechanical and overall COPs of 24.5 and 0.21, respectively. Exergy destruction primarily takes place in the ejector assembly, but ejector exergy efficiency improves with compression boosting. The system could reduce annual electric cooling loads by over 40% compared with a conventional local split air conditioner, with corresponding savings in electricity expenditure and GHG emissions.

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Section: Solar-assisted Ejector Space Cooling Systemmentioning

confidence: 98%

Thermodynamic Performance Investigation of a Small-Scale Solar Compression-Assisted Multi-Ejector Indoor Air Conditioning System for Hot Climate Conditions

Eveloy

Alkendi

2021

Energies

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“… 2 , 7 For a while, the search for 4th generation refrigerants remained elusive, 8 until the principles of green chemistry and engineering came to the rescue, 9 identifying hydrofluoroolefins (HFOs), hydrochlorofluoroolefins (HCFOs), hydrofluoroethers (HFEs), and blends of natural or synthetic refrigerants as potential alternatives. 10 − 12 …”

Section: Introductionmentioning

confidence: 99%

Searching for Sustainable Refrigerants by Bridging Molecular Modeling with Machine Learning

Alkhatib

Albà

Darwish

et al. 2022

Ind. Eng. Chem. Res.

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We present here a novel integrated approach employing machine learning algorithms for predicting thermophysical properties of fluids. The approach allows obtaining molecular parameters to be used in the polar soft-statistical associating fluid theory (SAFT) equation of state using molecular descriptors obtained from the conductor-like screening model for real solvents (COSMO-RS). The procedure is used for modeling 18 refrigerants including hydrofluorocarbons, hydrofluoroolefins, and hydrochlorofluoroolefins. The training dataset included six inputs obtained from COSMO-RS and five outputs from polar soft-SAFT parameters, with the accurate algorithm training ensured by its high statistical accuracy. The predicted molecular parameters were used in polar soft-SAFT for evaluating the thermophysical properties of the refrigerants such as density, vapor pressure, heat capacity, enthalpy of vaporization, and speed of sound. Predictions provided a good level of accuracy (AADs = 1.3–10.5%) compared to experimental data, and within a similar level of accuracy using parameters obtained from standard fitting procedures. Moreover, the predicted parameters provided a comparable level of predictive accuracy to parameters obtained from standard procedure when extended to modeling selected binary mixtures. The proposed approach enables bridging the gap in the data of thermodynamic properties of low global warming potential refrigerants, which hinders their technical evaluation and hence their final application.

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“…The majority (46 out of 51) were for blends containing R-1234yf or R-1234ze(E). A recent survey 8 gives an overview of the current state of HFO refrigerants from a variety of standpoints (thermodynamics, heat transfer, etc.). We consider a fairly broad range of fluids as "refrigerants", and these are listed in Table 1.…”

Section: Introductionmentioning

confidence: 99%

Survey of Data and Models for Refrigerant Mixtures Containing Halogenated Olefins

et al. 2021

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We survey existing data for refrigerant blends containing halogenated olefins (hydrofluoroolefins (HFO), hydrochlorofluoroolefins (HCFO), and hydrochloroolefins (HCO)) in the open literature. The data are primarily taken from the NIST SOURCE database and are presented in graphical form to demonstrate the relative coverage of the data. The primary conclusion is that blends containing halogenated olefins remain only sparsely measured in experiments, and some classes of data (e.g., speed-of-sound data) are particularly sparse for blends containing halogenated olefins. The second part of this study compares the thermodynamic models in NIST REFPROP against the experimental data sets and identifies systems (of which there are many) for which refitting of the thermodynamic model is required.

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HFO refrigerants: A review of present status and future prospects.

Cited by 119 publications

References 116 publications

Thermodynamic Performance Investigation of a Small-Scale Solar Compression-Assisted Multi-Ejector Indoor Air Conditioning System for Hot Climate Conditions

Thermodynamic Performance Investigation of a Small-Scale Solar Compression-Assisted Multi-Ejector Indoor Air Conditioning System for Hot Climate Conditions

Searching for Sustainable Refrigerants by Bridging Molecular Modeling with Machine Learning

Survey of Data and Models for Refrigerant Mixtures Containing Halogenated Olefins

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