Energetic and exergetic performance comparison of an ejector refrigeration system using modern low GWP refrigerants

Aggrey Mwesigye, Seth B. Dworkin

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

In this study, a novel model is used to precisely predict the performance of an ejector refrigeration system utilizing modern environmentally benign working fluids in both the critical and subcritical modes of operation. Energetic and exergetic performance of low global warming potential and non-ozone depleting HCFO and HFO refrigerants: R1233zd(E), R1224yd(Z), R1225ye(Z), hydrocarbon refrigerants: Isobutane and Isopentane and RE245cb2 is compared with that of conventional refrigerants: R141b and R245fa. The model takes the ejector area ratios, generator pressure, and evaporator pressure into account in the determination of the ejector loss coefficients. A program written in Engineering Equation Solver (EES) was used to obtain solutions of the developed mathematical model. In the analysis, ejector area ratios between 6.44 and 12.76, evaporator temperatures between 4 and 16°C, condenser temperatures between 25 and 50°C as well as generator temperatures between 70 and 110°C were used. Results show that Isobutane and R1225ye(Z) have the greatest performance, giving an over 150% increase in the coefficient of performance (COP) compared to R245fa. The increase in the COP with isopentane, RE245cb2, R1224yd(Z) and R1233zd(E) were as high as 22%, 32%, 16% and 14%, respectively at the lowest area ratio. Results further show that the ejector contributes the highest exergy losses (up to 55%, depending on the evaporator, condensing and generator temperatures) compared to the other components. The contribution of the condenser to the total exergy loss is up to 28%, for the generator it is up to 34% and up to 12% for the evaporator. The pump and the throttle valve give values lower than 0.5 and 9%, respectively for all the refrigerants.

Original languageEnglish (US)
Title of host publicationEnergy
PublisherAmerican Society of Mechanical Engineers (ASME)
ISBN (Electronic)9780791859438
DOIs
StatePublished - 2019
Externally publishedYes
EventASME 2019 International Mechanical Engineering Congress and Exposition, IMECE 2019 - Salt Lake City, United States
Duration: Nov 11 2019Nov 14 2019

Publication series

NameASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE)
Volume6

Conference

ConferenceASME 2019 International Mechanical Engineering Congress and Exposition, IMECE 2019
CountryUnited States
CitySalt Lake City
Period11/11/1911/14/19

Bibliographical note

Funding Information:
The authors acknowledge funding received from the Canadian Research Chairs Program and the Natural Sciences and Engineering Research Council (NSERC).

Publisher Copyright:
Copyright © 2019 ASME.

Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.

Keywords

  • Coefficient of performance
  • Ejector refrigeration system
  • Exergy analysis
  • Global warming potential

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