Development of a Hybrid Ejector-Compressor Refrigeration System with Improved Efficiency

Hdl Handle:
http://hdl.handle.net/11285/619507
Title:
Development of a Hybrid Ejector-Compressor Refrigeration System with Improved Efficiency
Authors:
Gutiérrez Ortiz, Alejandro
Issue Date:
2016-09-02
Abstract:
The present doctoral dissertation addresses the design of an ejector suitable for a thermally driven hybrid ejector-compressor cooling system; research was aimed at improving the performance of the ejector in terms of both critical backpressure and entrainment ratio. An ejector efficiency analysis is presented to establish a theoretical limit for the maximum achievable entrainment ratio of an ejector undergoing a fully reversible process without entropy generation; the main sources of irreversibility within the ejector are subsequently discussed. The shock circle model is implemented as a mean to predict the entrainment ratio for an ejector with a given set of nozzle and constant area section diameters; experimental results from the literature are presented and used to validate the model. A Computational Fluid Dynamics design exploration aimed at identifying the effects of the rest of the key geometrical parameters that are not covered by the mathematical model is also presented. In order to generalize the findings from this study for ejectors of different scales, the results are presented using non-dimensional parameters. The study showed that in order to guarantee a critical mode operation at the range of operating conditions suitable for a hybrid ejector-compressor cycle, only the constant area section or the nozzle throat diameters need to vary accordingly with the condenser backpressure. The optimum geometrical parameters found by the design exploration are used to propose an optimized ejector design, the Constant Rate of Momentum Change method is also implemented to generate a diffuser geometry that reduces one of the sources of entropy generation identified during the first stages of this research. The assessment of the performance increase for the proposed ejector is measured against a baseline design; the results showed that the new ejector outperforms the baseline in terms of both entrainment ratio and critical condenser backpressure. The thesis concludes with a study to quantify the thermal efficiency increase of a hybrid ejector-compressor system employing the proposed ejector, lastly, the design for a test stand to experimentally verify the findings of this research work is proposed.
Keywords:
Ejector; Fluid Dynamics; Hybrid Ejector-Compressor; Cooling System
Degree Program:
Doctorado en Ciencias de la Ingeniería
Advisors:
Dr. Noel León Rovira
Committee Member / Sinodal:
Ph. D. Alejandro J. García Cuéllar; Ph.D. Carlos Rivera Solorio; Dr. Martin H. Bremer Bremer; Ph.D. Humberto Aguayo Téllez
Degree Level:
Doctor en Ciencias de la Ingeniería
School:
Escuela de Ingeniería y Tecnologías de la Información
Campus Program:
Campus Monterrey
Discipline:
Ingeniería y Ciencias Aplicadas / Engineering & Applied Sciences
Appears in Collections:
Ciencias Exactas

Full metadata record

DC FieldValue Language
dc.contributor.advisorDr. Noel León Roviraen
dc.contributor.authorGutiérrez Ortiz, Alejandroen
dc.date2014-05en
dc.date.accessioned2016-09-02T11:04:39Z-
dc.date.available2016-09-02T11:04:39Z-
dc.date.issued2016-09-02-
dc.identifier.urihttp://hdl.handle.net/11285/619507en
dc.description.abstractThe present doctoral dissertation addresses the design of an ejector suitable for a thermally driven hybrid ejector-compressor cooling system; research was aimed at improving the performance of the ejector in terms of both critical backpressure and entrainment ratio. An ejector efficiency analysis is presented to establish a theoretical limit for the maximum achievable entrainment ratio of an ejector undergoing a fully reversible process without entropy generation; the main sources of irreversibility within the ejector are subsequently discussed. The shock circle model is implemented as a mean to predict the entrainment ratio for an ejector with a given set of nozzle and constant area section diameters; experimental results from the literature are presented and used to validate the model. A Computational Fluid Dynamics design exploration aimed at identifying the effects of the rest of the key geometrical parameters that are not covered by the mathematical model is also presented. In order to generalize the findings from this study for ejectors of different scales, the results are presented using non-dimensional parameters. The study showed that in order to guarantee a critical mode operation at the range of operating conditions suitable for a hybrid ejector-compressor cycle, only the constant area section or the nozzle throat diameters need to vary accordingly with the condenser backpressure. The optimum geometrical parameters found by the design exploration are used to propose an optimized ejector design, the Constant Rate of Momentum Change method is also implemented to generate a diffuser geometry that reduces one of the sources of entropy generation identified during the first stages of this research. The assessment of the performance increase for the proposed ejector is measured against a baseline design; the results showed that the new ejector outperforms the baseline in terms of both entrainment ratio and critical condenser backpressure. The thesis concludes with a study to quantify the thermal efficiency increase of a hybrid ejector-compressor system employing the proposed ejector, lastly, the design for a test stand to experimentally verify the findings of this research work is proposed.en
dc.languageenen
dc.language.isoenen
dc.rightsOpen Accessen
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/4.0/*
dc.titleDevelopment of a Hybrid Ejector-Compressor Refrigeration System with Improved Efficiencyen
dc.typeTesis de Doctoradoes
thesis.degree.grantorInstituto Tecnológico y de Estudios Superiores de Monterreyen
thesis.degree.levelDoctor en Ciencias de la Ingenieríaen
dc.contributor.committeememberPh. D. Alejandro J. García Cuéllaren
dc.contributor.committeememberPh.D. Carlos Rivera Solorioen
dc.contributor.committeememberDr. Martin H. Bremer Bremeren
dc.contributor.committeememberPh.D. Humberto Aguayo Téllezen
thesis.degree.disciplineEscuela de Ingeniería y Tecnologías de la Informaciónen
thesis.degree.nameDoctorado en Ciencias de la Ingenieríaen
dc.subject.keywordEjectoren
dc.subject.keywordFluid Dynamicsen
dc.subject.keywordHybrid Ejector-Compressoren
dc.subject.keywordCooling Systemen
thesis.degree.programCampus Monterreyen
dc.subject.disciplineIngeniería y Ciencias Aplicadas / Engineering & Applied Sciencesen
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