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International journal of refrigeration |
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Ajouter le résultat dans votre panierHistorical and present developments of ejector refrigeration systems with emphasis on transcritical carbon dioxide air-conditioning applications / Stefan Elbel in International journal of refrigeration, Vol. 34 N° 7 (Novembre 2011)
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1545-1561
Titre : Historical and present developments of ejector refrigeration systems with emphasis on transcritical carbon dioxide air-conditioning applications Titre original : Historique et développements actuels des systèmes frigorifiques à éjecteur, avec l'accent mis sur les applications en conditionnement d'air au dioxyde de carbone transcritiques Type de document : texte imprimé Auteurs : Stefan Elbel, Auteur Année de publication : 2011 Article en page(s) : pp. 1545-1561 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Ejector R744 Expansion Air conditioning Efficiency Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : This paper gives an overview of historical and present developments on how ejectors can be utilized to improve the performance of air-conditioning and refrigeration systems. Research on ejector refrigeration cycles that utilize low-grade energy sources to produce cooling is summarized. Another major class of ejector refrigeration cycles that is described tries to recover expansion work by means of a two-phase ejector. This particular approach appears to be very promising for transcritical carbon dioxide (CO2, R744) systems with inherently large throttling losses. The paper further presents the latest analytical and experimental results of a comprehensive study carried out to investigate possible performance improvements of transcritical R744 two-phase ejector systems. Relevant operational parameters were varied and effects on performance resulting from different ejector geometries were studied as well. Two-phase mixing shock waves inside the ejector were detected by recoding static wall pressure distributions. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002720 [article] Historical and present developments of ejector refrigeration systems with emphasis on transcritical carbon dioxide air-conditioning applications = Historique et développements actuels des systèmes frigorifiques à éjecteur, avec l'accent mis sur les applications en conditionnement d'air au dioxyde de carbone transcritiques [texte imprimé] / Stefan Elbel, Auteur . - 2011 . - pp. 1545-1561.
Génie Mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1545-1561
Mots-clés : Ejector R744 Expansion Air conditioning Efficiency Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : This paper gives an overview of historical and present developments on how ejectors can be utilized to improve the performance of air-conditioning and refrigeration systems. Research on ejector refrigeration cycles that utilize low-grade energy sources to produce cooling is summarized. Another major class of ejector refrigeration cycles that is described tries to recover expansion work by means of a two-phase ejector. This particular approach appears to be very promising for transcritical carbon dioxide (CO2, R744) systems with inherently large throttling losses. The paper further presents the latest analytical and experimental results of a comprehensive study carried out to investigate possible performance improvements of transcritical R744 two-phase ejector systems. Relevant operational parameters were varied and effects on performance resulting from different ejector geometries were studied as well. Two-phase mixing shock waves inside the ejector were detected by recoding static wall pressure distributions. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002720
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1562-1576
Titre : Vertical ground coupled steam ejector heat pump; thermal-economic modeling and optimization Titre original : Pompe à chaleur à éjecteur de vapeur couplée sol-eau: modélisation et optimisation thermoéconomiques Type de document : texte imprimé Auteurs : Sepehr Sanaye, Auteur ; Behzad Niroomand, Auteur Année de publication : 2011 Article en page(s) : pp. 1562-1576 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Heat pump Ground-water Ejector system Modelling Simulation Optimisation Performance Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : A vertical ground coupled steam ejector heat pump is a Ground Coupled Heat Pump (GCHP) with closed Vertical Ground Heat eXchanger (VGHX) which utilizes the steam ejector type of refrigeration cycle instead of the vapor-compression type.
This paper presents the modeling and optimizing a Ground-Coupled Steam Ejector Heat Pump (GC-SEHP) with closed VGHX. The system included two main sections of VGHX and steam ejector heat pump (SEHP), and was optimized by minimizing its total annual cost (TAC) as the objective function. Two optimization techniques (Nelder–Mead and Genetic Algorithm) were applied to guarantee the validity of optimization results.
For the given heating/cooling loads as well as for various climatic conditions, the optimum design parameters of GC-SEHP with closed VGHX were predicted.
Furthermore, the changes in TAC and optimum design parameters with the climatic conditions, cooling/heating capacity, soil type, and number of boreholes were discussed.DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710000502 [article] Vertical ground coupled steam ejector heat pump; thermal-economic modeling and optimization = Pompe à chaleur à éjecteur de vapeur couplée sol-eau: modélisation et optimisation thermoéconomiques [texte imprimé] / Sepehr Sanaye, Auteur ; Behzad Niroomand, Auteur . - 2011 . - pp. 1562-1576.
Génie Mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1562-1576
Mots-clés : Heat pump Ground-water Ejector system Modelling Simulation Optimisation Performance Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : A vertical ground coupled steam ejector heat pump is a Ground Coupled Heat Pump (GCHP) with closed Vertical Ground Heat eXchanger (VGHX) which utilizes the steam ejector type of refrigeration cycle instead of the vapor-compression type.
This paper presents the modeling and optimizing a Ground-Coupled Steam Ejector Heat Pump (GC-SEHP) with closed VGHX. The system included two main sections of VGHX and steam ejector heat pump (SEHP), and was optimized by minimizing its total annual cost (TAC) as the objective function. Two optimization techniques (Nelder–Mead and Genetic Algorithm) were applied to guarantee the validity of optimization results.
For the given heating/cooling loads as well as for various climatic conditions, the optimum design parameters of GC-SEHP with closed VGHX were predicted.
Furthermore, the changes in TAC and optimum design parameters with the climatic conditions, cooling/heating capacity, soil type, and number of boreholes were discussed.DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710000502
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1577-1586
Titre : Experimental analysis on the effect of internal heat exchanger in transcritical CO2 refrigeration cycle with two-phase ejector Titre original : Analyse expérimentale d'un échangeur de chaleur interne dans un cycle frigorifique au CO2 à éjecteur diphasique Type de document : texte imprimé Auteurs : Masafumi Nakagawa, Auteur ; Ariel R. Marasigan, Auteur ; Takanori Matsukawa, Auteur Année de publication : 2011 Article en page(s) : pp. 1577-1586 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Refrigeration system Compression system Ejector system Carbon dioxide Transcritical cycle Heat exchanger Experiment-performance Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : The performance of CO2 ejector refrigeration system needs further improvement to make CO2 more viable than traditional harmful refrigerants. In this research, the effect of internal heat exchanger (IHX) in the performance of ejector refrigeration system was analyzed experimentally and compared with conventional expansion refrigeration system. Experiments were performed at different operating pressure and temperature for the cases of without IHX, 30 cm IHX and 60 cm IHX. The results showed that IHX significantly increased the coefficient of performance (COP) of ejector system. At the conditions used in this research, the ejector system with 60 cm IHX provided the maximum COP improvement of up to 27% compared to similar conventional system. The motive nozzle’s inlet condition had significant effect on the performance of ejector system. The results also confirmed the presence of considerable amount of liquid refrigerant at separator’s gas outlet of ejector system which was deemed possible in our previous research. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710000629 [article] Experimental analysis on the effect of internal heat exchanger in transcritical CO2 refrigeration cycle with two-phase ejector = Analyse expérimentale d'un échangeur de chaleur interne dans un cycle frigorifique au CO2 à éjecteur diphasique [texte imprimé] / Masafumi Nakagawa, Auteur ; Ariel R. Marasigan, Auteur ; Takanori Matsukawa, Auteur . - 2011 . - pp. 1577-1586.
Génie Mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1577-1586
Mots-clés : Refrigeration system Compression system Ejector system Carbon dioxide Transcritical cycle Heat exchanger Experiment-performance Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : The performance of CO2 ejector refrigeration system needs further improvement to make CO2 more viable than traditional harmful refrigerants. In this research, the effect of internal heat exchanger (IHX) in the performance of ejector refrigeration system was analyzed experimentally and compared with conventional expansion refrigeration system. Experiments were performed at different operating pressure and temperature for the cases of without IHX, 30 cm IHX and 60 cm IHX. The results showed that IHX significantly increased the coefficient of performance (COP) of ejector system. At the conditions used in this research, the ejector system with 60 cm IHX provided the maximum COP improvement of up to 27% compared to similar conventional system. The motive nozzle’s inlet condition had significant effect on the performance of ejector system. The results also confirmed the presence of considerable amount of liquid refrigerant at separator’s gas outlet of ejector system which was deemed possible in our previous research. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710000629
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1587-1595
Titre : Research on air-source heat pump coupled with economized vapor injection scroll compressor and ejector Titre original : Recherches sur une pompe à chaleur air-eau couplée à un compresseur à spirale et un éjecteur à injection de vapeur muni d'un économiseur Type de document : texte imprimé Auteurs : Xu Shuxue, Auteur ; Ma Guoyuan, Auteur Année de publication : 2011 Article en page(s) : pp. 1587-1595 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Heat pump Air-source Scroll compressor Injection Ejector Design Calculation Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : The performance of the heat pump can be improved further when running under low temperature conditions when an ejector is used in a heat pump system coupled with economized vapor injection (EVI) scroll compressor. In this paper, the design method of the heat pump system with ejector (EVIe) is presented, and the process for designing the heat pump with ejector has been summarized. The optimal location of the vapor injection inlets is at the place where the vapor can inject into the working chambers when they just be closed. The reasonable value for the entrainment ratio u of the ejector is between 0.1 and 0.2. One prototype heat pump was designed under the condition of the evaporation temperature of −20 °C, and an experimental setup was established to test the prototype. The measured results demonstrated that the heating EER of the heat pump system with ejector could reach about 4% higher than that of the system without ejector when the heating capacity remained nearly constant. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710001192 [article] Research on air-source heat pump coupled with economized vapor injection scroll compressor and ejector = Recherches sur une pompe à chaleur air-eau couplée à un compresseur à spirale et un éjecteur à injection de vapeur muni d'un économiseur [texte imprimé] / Xu Shuxue, Auteur ; Ma Guoyuan, Auteur . - 2011 . - pp. 1587-1595.
Génie Mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1587-1595
Mots-clés : Heat pump Air-source Scroll compressor Injection Ejector Design Calculation Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : The performance of the heat pump can be improved further when running under low temperature conditions when an ejector is used in a heat pump system coupled with economized vapor injection (EVI) scroll compressor. In this paper, the design method of the heat pump system with ejector (EVIe) is presented, and the process for designing the heat pump with ejector has been summarized. The optimal location of the vapor injection inlets is at the place where the vapor can inject into the working chambers when they just be closed. The reasonable value for the entrainment ratio u of the ejector is between 0.1 and 0.2. One prototype heat pump was designed under the condition of the evaporation temperature of −20 °C, and an experimental setup was established to test the prototype. The measured results demonstrated that the heating EER of the heat pump system with ejector could reach about 4% higher than that of the system without ejector when the heating capacity remained nearly constant. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710001192
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1596-1603
Titre : A novel ejector-absorption combined refrigeration cycle Titre original : Nouveau cycle frigorifique associant un éjecteur et l'absorption Type de document : texte imprimé Auteurs : Daliang Hong, Auteur ; Guangming Chen, Auteur ; Limin Tang, Auteur Année de publication : 2011 Article en page(s) : pp. 1596-1603 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Refrigeration system Absorption system Ejector system Design Simulation Performance Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : This paper presents a novel ejector-absorption combined refrigeration cycle. When the temperature of the heat source is high enough, this cycle will work as a double-effect cycle. If the temperature of the heat source is lower than required temperature of heat source used to drive conventional double-effect absorption refrigeration cycle but much higher than required temperature of heat source used to drive conventional single-effect absorption refrigeration cycle, the COP of new cycle will also be higher than that of conventional single-effect absorption refrigeration cycle. Simulation results show that the COP of the cycle is 30% higher than that of the conventional single-effect absorption refrigeration cycle at some working conditions even in the later case. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710001532 [article] A novel ejector-absorption combined refrigeration cycle = Nouveau cycle frigorifique associant un éjecteur et l'absorption [texte imprimé] / Daliang Hong, Auteur ; Guangming Chen, Auteur ; Limin Tang, Auteur . - 2011 . - pp. 1596-1603.
Génie Mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1596-1603
Mots-clés : Refrigeration system Absorption system Ejector system Design Simulation Performance Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : This paper presents a novel ejector-absorption combined refrigeration cycle. When the temperature of the heat source is high enough, this cycle will work as a double-effect cycle. If the temperature of the heat source is lower than required temperature of heat source used to drive conventional double-effect absorption refrigeration cycle but much higher than required temperature of heat source used to drive conventional single-effect absorption refrigeration cycle, the COP of new cycle will also be higher than that of conventional single-effect absorption refrigeration cycle. Simulation results show that the COP of the cycle is 30% higher than that of the conventional single-effect absorption refrigeration cycle at some working conditions even in the later case. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710001532
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1604-1613
Titre : Experimental investigation on the effect of mixing length on the performance of two-phase ejector for CO2 refrigeration cycle with and without heat exchanger Titre original : Etude expérimentale sur l'effet de la longueur du mélangeur sur la performance d'un éjecteur diphasique d'un cycle frigorifique au CO2 avec ou sans échangeur Type de document : texte imprimé Auteurs : M. Nakagawa, Auteur ; Ariel R. Marasigan, Auteur ; T. Matsukawa, Auteur Année de publication : 2011 Article en page(s) : pp. 1604-1613 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Carbon dioxide Coefficient of performance Ejector Experiment Two-phase Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : In ejector system using the promising natural refrigerant CO2, the mixing of high-speed two-phase primary flow and suction vapor is crucial in designing an efficient ejector. In this study, the effect of mixing length on ejector system performance was analyzed experimentally. The mixing lengths used were 5 mm, 15 mm, and 25 mm, with constant rectangular cross-section. The experiments were performed for both ejector and conventional expansion systems with and without internal heat exchanger (IHX) at different operating conditions. Based on the experimental results, mixing length had significant effect on entrainment ratio and on magnitude and profile of pressure recovery. The 5 mm and 15 mm types yielded the lowest and highest ejector efficiency and COP in all of the conditions used in this research, respectively. The use of IHX had net positive effect on system performance which verified the results of our previous study. A COP improvement of up to 26% over conventional system was obtained but improper sizing of mixing length lowered the COP by as much as 10%. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710001672 [article] Experimental investigation on the effect of mixing length on the performance of two-phase ejector for CO2 refrigeration cycle with and without heat exchanger = Etude expérimentale sur l'effet de la longueur du mélangeur sur la performance d'un éjecteur diphasique d'un cycle frigorifique au CO2 avec ou sans échangeur [texte imprimé] / M. Nakagawa, Auteur ; Ariel R. Marasigan, Auteur ; T. Matsukawa, Auteur . - 2011 . - pp. 1604-1613.
Génie Mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1604-1613
Mots-clés : Carbon dioxide Coefficient of performance Ejector Experiment Two-phase Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : In ejector system using the promising natural refrigerant CO2, the mixing of high-speed two-phase primary flow and suction vapor is crucial in designing an efficient ejector. In this study, the effect of mixing length on ejector system performance was analyzed experimentally. The mixing lengths used were 5 mm, 15 mm, and 25 mm, with constant rectangular cross-section. The experiments were performed for both ejector and conventional expansion systems with and without internal heat exchanger (IHX) at different operating conditions. Based on the experimental results, mixing length had significant effect on entrainment ratio and on magnitude and profile of pressure recovery. The 5 mm and 15 mm types yielded the lowest and highest ejector efficiency and COP in all of the conditions used in this research, respectively. The use of IHX had net positive effect on system performance which verified the results of our previous study. A COP improvement of up to 26% over conventional system was obtained but improper sizing of mixing length lowered the COP by as much as 10%. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710001672
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1614-1625
Titre : Experimental study on the improvement of CO2 air conditioning system performance using an ejector Titre original : Etude expérimentale sur l'amélioration de la performance d'un système de conditionnement d'air au CO2 à l'aide d'un éjecteur Type de document : texte imprimé Auteurs : Jae Seung Lee, Auteur ; Mo Se Kim, Auteur ; Min Soo Kim, Auteur Année de publication : 2011 Article en page(s) : pp. 1614-1625 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Air conditioning Carbon dioxide Ejector Performance Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : Several preceding researches have evidenced that the transcritical air conditioning system using CO2 as a refrigerant has an inherent inefficiency resulting in degraded steady-state system performance of a CO2 air conditioning system compared with that of a conventional air conditioning system. As a practical improvement, two-phase ejector was considered in place of expansion device in this study. The two-phase ejector for CO2 air conditioning system was designed and developed considering the non-equilibrium state for evaluating the sonic velocity and the critical mass flux. The experiments of performance with respect to variation of ejector geometry such as the motive nozzle throat diameter, mixing section diameter and the distance between motive nozzle and diffuser were carried out. There exist optimum design parameters in each test. Experiments showed that the coefficient of performance of the system using an ejector was about 15% higher than that of the conventional system. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710001714 [article] Experimental study on the improvement of CO2 air conditioning system performance using an ejector = Etude expérimentale sur l'amélioration de la performance d'un système de conditionnement d'air au CO2 à l'aide d'un éjecteur [texte imprimé] / Jae Seung Lee, Auteur ; Mo Se Kim, Auteur ; Min Soo Kim, Auteur . - 2011 . - pp. 1614-1625.
Génie Mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1614-1625
Mots-clés : Air conditioning Carbon dioxide Ejector Performance Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : Several preceding researches have evidenced that the transcritical air conditioning system using CO2 as a refrigerant has an inherent inefficiency resulting in degraded steady-state system performance of a CO2 air conditioning system compared with that of a conventional air conditioning system. As a practical improvement, two-phase ejector was considered in place of expansion device in this study. The two-phase ejector for CO2 air conditioning system was designed and developed considering the non-equilibrium state for evaluating the sonic velocity and the critical mass flux. The experiments of performance with respect to variation of ejector geometry such as the motive nozzle throat diameter, mixing section diameter and the distance between motive nozzle and diffuser were carried out. There exist optimum design parameters in each test. Experiments showed that the coefficient of performance of the system using an ejector was about 15% higher than that of the conventional system. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710001714
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1626-1632
Titre : Use of variable geometry ejector with cold store to achieve high solar fraction for solar cooling Titre original : Utilisation d'un éjecteur à géométrie variable avec accumulation thermique pour obtenir une fraction solaire élevée dans le domaine du froid solaire Type de document : texte imprimé Auteurs : M. Dennis, Auteur ; K. Garzoli, Auteur Année de publication : 2011 Article en page(s) : pp. 1626-1632 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Solar collector Ejector System Thermal storage Modelling Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : Concerns over environmental impact of heat pump cooling systems have led to a revival of solar ejector cooling systems. In order to achieve high solar fractions, the common approach is to increase the solar collector area. However, this is costly and does not provide cooling after sunset. This paper uses software modelling to examine the use of variable geometry ejectors and cold stores to increase the annual yield of an ejector system. The study concludes that a variable geometry ejector is able to increase yield by 8–13% compared to a fixed geometry ejector. However, a 46–50% increase in solar fraction is available if a 60 MJ cold store is included compared to a fixed geometry ejector without storage and up to 63% increase in solar fraction is available if a variable geometry ejector and 60 MJ cold store is used. Alternatively, the modelling shows how the solar collector area may be decreased if a cold store is used and this may benefit the capital and operating cost of the system. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710001787 [article] Use of variable geometry ejector with cold store to achieve high solar fraction for solar cooling = Utilisation d'un éjecteur à géométrie variable avec accumulation thermique pour obtenir une fraction solaire élevée dans le domaine du froid solaire [texte imprimé] / M. Dennis, Auteur ; K. Garzoli, Auteur . - 2011 . - pp. 1626-1632.
Génie Mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1626-1632
Mots-clés : Solar collector Ejector System Thermal storage Modelling Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : Concerns over environmental impact of heat pump cooling systems have led to a revival of solar ejector cooling systems. In order to achieve high solar fractions, the common approach is to increase the solar collector area. However, this is costly and does not provide cooling after sunset. This paper uses software modelling to examine the use of variable geometry ejectors and cold stores to increase the annual yield of an ejector system. The study concludes that a variable geometry ejector is able to increase yield by 8–13% compared to a fixed geometry ejector. However, a 46–50% increase in solar fraction is available if a 60 MJ cold store is included compared to a fixed geometry ejector without storage and up to 63% increase in solar fraction is available if a variable geometry ejector and 60 MJ cold store is used. Alternatively, the modelling shows how the solar collector area may be decreased if a cold store is used and this may benefit the capital and operating cost of the system. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710001787
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1633-1640
Titre : Flow visualization in supersonic ejectors using laser tomography techniques Titre original : Visualisation de l’écoulement au sein d’éjecteurs supersoniques par techniques de tomographie laser Type de document : texte imprimé Auteurs : Ala Bouhanguel, Auteur ; Philippe Desevaux, Auteur ; Eric Gavignet, Auteur Année de publication : 2011 Article en page(s) : pp. 1633-1640 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Ejector Flow Visualization Tomography Laser Mixing Instability Design Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : This paper presents flow imaging techniques developed for investigating flow in ejectors. These visualization techniques use the laser sheet method but differ from each other by the kind of the illumination source, the polarization direction of the incident light and the type of the scattering tracers. Each of these methods enables the visualization of specific phenomena (shock structure, flow instabilities, mixing process). Although the flow visualizations are primarily qualitative, they allow the determination of the flow regime, the measurement of the non-mixing length, can indicate suggestions for the design of ejectors and provide the possibility to validate numerical simulations. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002021 [article] Flow visualization in supersonic ejectors using laser tomography techniques = Visualisation de l’écoulement au sein d’éjecteurs supersoniques par techniques de tomographie laser [texte imprimé] / Ala Bouhanguel, Auteur ; Philippe Desevaux, Auteur ; Eric Gavignet, Auteur . - 2011 . - pp. 1633-1640.
Génie Mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1633-1640
Mots-clés : Ejector Flow Visualization Tomography Laser Mixing Instability Design Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : This paper presents flow imaging techniques developed for investigating flow in ejectors. These visualization techniques use the laser sheet method but differ from each other by the kind of the illumination source, the polarization direction of the incident light and the type of the scattering tracers. Each of these methods enables the visualization of specific phenomena (shock structure, flow instabilities, mixing process). Although the flow visualizations are primarily qualitative, they allow the determination of the flow regime, the measurement of the non-mixing length, can indicate suggestions for the design of ejectors and provide the possibility to validate numerical simulations. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002021
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1641-1648
Titre : Prediction of condensation in steam ejector for a refrigeration system Titre original : Prévision de la condensation dans l'éjecteur à vapeur d'un système frigorifique Type de document : texte imprimé Auteurs : Giuseppe Grazzini, Auteur ; Adriano Milazzo, Auteur ; Samuele Piazzini, Auteur Année de publication : 2011 Article en page(s) : pp. 1641-1648 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Ejector Condensation Subcooling Water Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : An experimental refrigeration system based on a two-stage steam ejector was set-up in the Thermodynamics and Heat Transfer Laboratory of our Department. The system optimization and realization have been described elsewhere ( [Grazzini and Mariani, 1998] and [Grazzini and Rocchetti, 2008] ). In both stages, primary flows are highly supersonic and reach low pressure and temperature levels. As usual in the literature, an ideal gas model was used during the design process. This paper is intended to check the validity of this assumption. In order to understand the actual working condition of our system, several models have been compared. The presence of high flow speed suggests the existence of metastable conditions. To set the border for the metastable region, the spinodal curve has been drawn. Isentropic expansion of vapour through the nozzle, modelled as ideal gas, seems well within the metastable zone. However, the Classic Nucleation Theory shows that the Wilson line is crossed at the nozzle throat. Condensation produces a marked difference in the conditions at the nozzle exit. Results coming from the present analysis will be used in further optimization of the experimental ejector design. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002264 [article] Prediction of condensation in steam ejector for a refrigeration system = Prévision de la condensation dans l'éjecteur à vapeur d'un système frigorifique [texte imprimé] / Giuseppe Grazzini, Auteur ; Adriano Milazzo, Auteur ; Samuele Piazzini, Auteur . - 2011 . - pp. 1641-1648.
Génie Mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1641-1648
Mots-clés : Ejector Condensation Subcooling Water Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : An experimental refrigeration system based on a two-stage steam ejector was set-up in the Thermodynamics and Heat Transfer Laboratory of our Department. The system optimization and realization have been described elsewhere ( [Grazzini and Mariani, 1998] and [Grazzini and Rocchetti, 2008] ). In both stages, primary flows are highly supersonic and reach low pressure and temperature levels. As usual in the literature, an ideal gas model was used during the design process. This paper is intended to check the validity of this assumption. In order to understand the actual working condition of our system, several models have been compared. The presence of high flow speed suggests the existence of metastable conditions. To set the border for the metastable region, the spinodal curve has been drawn. Isentropic expansion of vapour through the nozzle, modelled as ideal gas, seems well within the metastable zone. However, the Classic Nucleation Theory shows that the Wilson line is crossed at the nozzle throat. Condensation produces a marked difference in the conditions at the nozzle exit. Results coming from the present analysis will be used in further optimization of the experimental ejector design. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002264
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1649-1656
Titre : Design-theoretical study of cascade CO2 sub-critical mechanical compression/butane ejector cooling cycle Titre original : Etude sur la conception et sur un cycle théorique de refroidissement à compression mécanique en cascade au CO2 subcritique, muni d'un système à éjecteur au butane Type de document : texte imprimé Auteurs : V.O. Petrenko, Auteur ; B.J. Huang, Auteur ; V.O. Ierin, Auteur Année de publication : 2011 Article en page(s) : pp. 1649-1656 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Carbon dioxide Butane Cascade system Vapor Compression Ejector Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : In this paper an innovative micro-trigeneration system composed of a cogeneration system and a cascade refrigeration cycle is proposed. The cogeneration system is a combined heat and power system for electricity generation and heat production. The cascade refrigeration cycle is the combination of a CO2 mechanical compression refrigerating machine (MCRM), powered by generated electricity, and an ejector cooling machine (ECM), driven by waste heat and using refrigerant R600. Effect of the cycle operating conditions on ejector and ejector cycle performances is studied. Optimal geometry of the ejector and performance characteristics of ECM are determined at wide range of the operating conditions. The paper also describes a theoretical analysis of the CO2 sub-critical cycle and shows the effect of the MCRM evaporating temperature on the cascade system performance. The obtained data provide necessary information to design a small-scale cascade system with cooling capacity of 10 kW for application in micro-trigeneration systems. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002732 [article] Design-theoretical study of cascade CO2 sub-critical mechanical compression/butane ejector cooling cycle = Etude sur la conception et sur un cycle théorique de refroidissement à compression mécanique en cascade au CO2 subcritique, muni d'un système à éjecteur au butane [texte imprimé] / V.O. Petrenko, Auteur ; B.J. Huang, Auteur ; V.O. Ierin, Auteur . - 2011 . - pp. 1649-1656.
Génie Mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1649-1656
Mots-clés : Carbon dioxide Butane Cascade system Vapor Compression Ejector Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : In this paper an innovative micro-trigeneration system composed of a cogeneration system and a cascade refrigeration cycle is proposed. The cogeneration system is a combined heat and power system for electricity generation and heat production. The cascade refrigeration cycle is the combination of a CO2 mechanical compression refrigerating machine (MCRM), powered by generated electricity, and an ejector cooling machine (ECM), driven by waste heat and using refrigerant R600. Effect of the cycle operating conditions on ejector and ejector cycle performances is studied. Optimal geometry of the ejector and performance characteristics of ECM are determined at wide range of the operating conditions. The paper also describes a theoretical analysis of the CO2 sub-critical cycle and shows the effect of the MCRM evaporating temperature on the cascade system performance. The obtained data provide necessary information to design a small-scale cascade system with cooling capacity of 10 kW for application in micro-trigeneration systems. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002732
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1657-1667
Titre : Simulation of an ejector used in refrigeration systems Titre original : Simulation d′un éjecteur utilisé dans les systèmes frigorifiques Type de document : texte imprimé Auteurs : M. Elakhdar, Auteur ; E. Nehdi, Auteur ; L. Kairouani, Auteur Année de publication : 2011 Article en page(s) : pp. 1657-1667 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Ejector Performance Operating regime Mathematical simulation Refrigerant Environmentally friendly Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : The present study describes a computer simulation model for refrigerant ejector. A one-dimensional mathematical model was developed using the equations governing the flow and thermodynamics based on the constant-area ejector flow model. The model includes effects of friction at the constant-area mixing chamber. The current model is based on the NIST-REFPROP database for refrigerants’ properties calculations. The simulated performance is compared with the available experimental data from the literature for validation. The effects of operating parameters and environment friendly refrigerants on critical entrainment ratio are studied. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002860 [article] Simulation of an ejector used in refrigeration systems = Simulation d′un éjecteur utilisé dans les systèmes frigorifiques [texte imprimé] / M. Elakhdar, Auteur ; E. Nehdi, Auteur ; L. Kairouani, Auteur . - 2011 . - pp. 1657-1667.
Génie Mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1657-1667
Mots-clés : Ejector Performance Operating regime Mathematical simulation Refrigerant Environmentally friendly Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : The present study describes a computer simulation model for refrigerant ejector. A one-dimensional mathematical model was developed using the equations governing the flow and thermodynamics based on the constant-area ejector flow model. The model includes effects of friction at the constant-area mixing chamber. The current model is based on the NIST-REFPROP database for refrigerants’ properties calculations. The simulated performance is compared with the available experimental data from the literature for validation. The effects of operating parameters and environment friendly refrigerants on critical entrainment ratio are studied. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002860
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1668-1675
Titre : Experimental and numerical analysis of a variable area ratio steam ejector Titre original : Analyse numérique et expérimentale d’un éjecteur de vapeur à ratio de section variable Type de document : texte imprimé Auteurs : Szabolcs Varga, Auteur ; Armando C. Oliveira, Auteur ; Xiaoli Ma, Auteur Année de publication : 2011 Article en page(s) : pp. 1668-1675 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Ejector system Performance Computational fluid dynamics Experimentation Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : In the present paper, experimental and CFD results for a 5 kW capacity steam ejector with variable primary nozzle geometry are presented and compared. The variable geometry was achieved by applying a movable spindle at the primary nozzle inlet. Operating conditions were considered in a range that would be suitable for an air-conditioning application, with thermal energy supplied by vacuum tube solar collectors. The CFD model was based on the axi-symmetric representation of the experimental ejector, using water as working fluid. The experimental entrainment ratio varied in the range of 0.1–0.5 depending on operating conditions and spindle tip position. It was found that the primary flow rate can be successfully adjusted by the spindle. CFD and experimental primary flow rates agreed well, with an average relative error of 7.7%. CFD predicted the secondary flow rate and entrainment ratio with good accuracy only in 70% of the cases. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002951 [article] Experimental and numerical analysis of a variable area ratio steam ejector = Analyse numérique et expérimentale d’un éjecteur de vapeur à ratio de section variable [texte imprimé] / Szabolcs Varga, Auteur ; Armando C. Oliveira, Auteur ; Xiaoli Ma, Auteur . - 2011 . - pp. 1668-1675.
Génie Mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1668-1675
Mots-clés : Ejector system Performance Computational fluid dynamics Experimentation Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : In the present paper, experimental and CFD results for a 5 kW capacity steam ejector with variable primary nozzle geometry are presented and compared. The variable geometry was achieved by applying a movable spindle at the primary nozzle inlet. Operating conditions were considered in a range that would be suitable for an air-conditioning application, with thermal energy supplied by vacuum tube solar collectors. The CFD model was based on the axi-symmetric representation of the experimental ejector, using water as working fluid. The experimental entrainment ratio varied in the range of 0.1–0.5 depending on operating conditions and spindle tip position. It was found that the primary flow rate can be successfully adjusted by the spindle. CFD and experimental primary flow rates agreed well, with an average relative error of 7.7%. CFD predicted the secondary flow rate and entrainment ratio with good accuracy only in 70% of the cases. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002951
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1676-1683
Titre : Experimental evaluation of an ejector as liquid re-circulator in an overfeed NH3 system with a plate evaporator Titre original : Evaluation expérimentale d'un éjecteur utilisé pour recirculer l'ammoniac liquide dans un système avec un évaporateur à plaques suralimenté Type de document : texte imprimé Auteurs : J. Alberto Dopazo, Auteur ; José Fernández-Seara, Auteur Année de publication : 2011 Article en page(s) : pp. 1676-1683 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Ejector Evaporator System Overfeed Ammonia Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : This paper deals with the experimental performance evaluation of an ejector, linked to a manual expansion valve, working as a liquid re-circulator component in an overfeed NH3 plate evaporator. The evaporator was tested in a single stage system belonging to a cascade refrigeration system prototype. The evaporator is an ALFANOVA HP76 plate heat exchanger with 50 plates. A Phillips ejector with a 1/2″ diameter throat and 1.4 mm diameter nozzle was used. The recirculation rate was experimentally determined for different operating conditions. Experimental data are reported for volumetric flow rate at the manual expansion valve inlet from 0.8 to 1.6 l min−1, evaporating pressure from 0.14 to 0.22 MPa and condensing pressure from 0.85 to 1 MPa. The experimental result showed recirculation rates between 2 and 4. The evaporating capacity varied from 9.48 kW to 18.37 kW. In addition, another two nozzles were tested and the results are also presented and discussed. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002987 [article] Experimental evaluation of an ejector as liquid re-circulator in an overfeed NH3 system with a plate evaporator = Evaluation expérimentale d'un éjecteur utilisé pour recirculer l'ammoniac liquide dans un système avec un évaporateur à plaques suralimenté [texte imprimé] / J. Alberto Dopazo, Auteur ; José Fernández-Seara, Auteur . - 2011 . - pp. 1676-1683.
Génie Mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1676-1683
Mots-clés : Ejector Evaporator System Overfeed Ammonia Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : This paper deals with the experimental performance evaluation of an ejector, linked to a manual expansion valve, working as a liquid re-circulator component in an overfeed NH3 plate evaporator. The evaporator was tested in a single stage system belonging to a cascade refrigeration system prototype. The evaporator is an ALFANOVA HP76 plate heat exchanger with 50 plates. A Phillips ejector with a 1/2″ diameter throat and 1.4 mm diameter nozzle was used. The recirculation rate was experimentally determined for different operating conditions. Experimental data are reported for volumetric flow rate at the manual expansion valve inlet from 0.8 to 1.6 l min−1, evaporating pressure from 0.14 to 0.22 MPa and condensing pressure from 0.85 to 1 MPa. The experimental result showed recirculation rates between 2 and 4. The evaporating capacity varied from 9.48 kW to 18.37 kW. In addition, another two nozzles were tested and the results are also presented and discussed. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002987
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1684-1698
Titre : Ejector design and theoretical study of R134a ejector refrigeration cycle Titre original : Conception de l'éjecteur et étude théorique d'un cycle frigorifique au R134a à éjecteur Type de document : texte imprimé Auteurs : A. Khalil, Auteur ; M. Fatouh, Auteur ; E. Elgendy, Auteur Année de publication : 2011 Article en page(s) : pp. 1684-1698 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : R134a Ejector System Design Air conditioning Performance Modelling Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : In the present paper, a mathematical model is developed to design R134a ejector and to predict the performance characteristics of a vapor jet refrigeration system over a wide range of the investigated parameters. These parameters include boiling temperature (65–85 °C), condensing temperature (25–40 °C), evaporating temperature (0–10 °C), degrees of superheat (0–15 °C), nozzle efficiency (0.75–0.95) and diffuser efficiency (0.75–0.95). Simulated results showed that the present model data are in good agreement with experimental data in the literature with an average error of 6%. It is found that the ejector area ratio at boiling temperature of 85 °C is about double that at boiling temperature of 65 °C for various evaporating and condensing temperatures. The present results confirm that waste heat sources of temperature ranging from 65 to 85 °C are adequate to operate vapor jet refrigeration system for air-conditioning applications. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711000181 [article] Ejector design and theoretical study of R134a ejector refrigeration cycle = Conception de l'éjecteur et étude théorique d'un cycle frigorifique au R134a à éjecteur [texte imprimé] / A. Khalil, Auteur ; M. Fatouh, Auteur ; E. Elgendy, Auteur . - 2011 . - pp. 1684-1698.
Génie Mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1684-1698
Mots-clés : R134a Ejector System Design Air conditioning Performance Modelling Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : In the present paper, a mathematical model is developed to design R134a ejector and to predict the performance characteristics of a vapor jet refrigeration system over a wide range of the investigated parameters. These parameters include boiling temperature (65–85 °C), condensing temperature (25–40 °C), evaporating temperature (0–10 °C), degrees of superheat (0–15 °C), nozzle efficiency (0.75–0.95) and diffuser efficiency (0.75–0.95). Simulated results showed that the present model data are in good agreement with experimental data in the literature with an average error of 6%. It is found that the ejector area ratio at boiling temperature of 85 °C is about double that at boiling temperature of 65 °C for various evaporating and condensing temperatures. The present results confirm that waste heat sources of temperature ranging from 65 to 85 °C are adequate to operate vapor jet refrigeration system for air-conditioning applications. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711000181
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1699-1706
Titre : Theoretical study and design of a low-grade heat-driven pilot ejector refrigeration machine operating with butane and isobutane and intended for cooling of gas transported in a gas-main pipeline Titre original : Etude théorique et conception d'un système frigorifique pilote à éjecteur à récupération de chaleur á butane et á isobutane destiné à refroidir le gaz acheminé dans un conduit Type de document : texte imprimé Auteurs : V.O. Petrenko, Auteur ; O.S. Volovyk, Auteur Année de publication : 2011 Article en page(s) : pp. 1699-1706 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Ejector System Butane Isobutane Gas turbine Gas pipeline Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : This paper describes the construction and performance of a novel combined system intended for natural gas transportation and power production, and for cooling of gas transported in a gas-main pipeline. The proposed system includes a gas turbine compressor, a combined electrogenerating plant and an ejector refrigeration unit operating with a hydrocarbon refrigerant. The combined electrogenerating plant consists of a high-temperature steam–power cycle and a low-temperature hydrocarbon vapor power cycle, which together comprise a binary vapor system. The combined system is designed for the highest possible effectiveness of power generation and could find wide application in gas-transmission systems of gas-main pipelines. Application of the proposed system would enable year-round power generation and provide cooling of natural gas during periods of high ambient temperature operation. This paper presents the main results of a theoretical study and design performance specifications of a low-grade heat-driven pilot ejector refrigeration machine operating with butane and isobutane. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711000314 [article] Theoretical study and design of a low-grade heat-driven pilot ejector refrigeration machine operating with butane and isobutane and intended for cooling of gas transported in a gas-main pipeline = Etude théorique et conception d'un système frigorifique pilote à éjecteur à récupération de chaleur á butane et á isobutane destiné à refroidir le gaz acheminé dans un conduit [texte imprimé] / V.O. Petrenko, Auteur ; O.S. Volovyk, Auteur . - 2011 . - pp. 1699-1706.
Génie Mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1699-1706
Mots-clés : Ejector System Butane Isobutane Gas turbine Gas pipeline Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : This paper describes the construction and performance of a novel combined system intended for natural gas transportation and power production, and for cooling of gas transported in a gas-main pipeline. The proposed system includes a gas turbine compressor, a combined electrogenerating plant and an ejector refrigeration unit operating with a hydrocarbon refrigerant. The combined electrogenerating plant consists of a high-temperature steam–power cycle and a low-temperature hydrocarbon vapor power cycle, which together comprise a binary vapor system. The combined system is designed for the highest possible effectiveness of power generation and could find wide application in gas-transmission systems of gas-main pipelines. Application of the proposed system would enable year-round power generation and provide cooling of natural gas during periods of high ambient temperature operation. This paper presents the main results of a theoretical study and design performance specifications of a low-grade heat-driven pilot ejector refrigeration machine operating with butane and isobutane. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711000314
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1707-1716
Titre : Performance of ejector cooling systems using low ecological impact refrigerants Titre original : Performance des systèmes de refroidissement à éjecteur employant des frigorigènes exerçant un faible impact sur l'environnement Type de document : texte imprimé Auteurs : Raul Roman, Auteur ; Jorge I. Hernandez, Auteur Année de publication : 2011 Article en page(s) : pp. 1707-1716 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Cooling Ejector system Performance Hydrocarbon R134a R152a Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : The theoretical behaviour of an ejector cooling system, using as working fluids propane, butane, isobutane, R152a and R134a, is obtained. The ejector works as a thermo-compressor that is simulated with a validated one-dimensional mathematical model, whose errors are lower than 6%. For a system unitary cooling capacity, a parametric study is carried out varying the generation, condensation and evaporation temperatures. From the obtained data, a complete analysis of the system performance can be achieved when the ejector and system operation parameters are considered. The best performance corresponds to the system using propane, because has the highest system coefficient of performance and its ejector has the maximum entrainment ratio value, the least area ratio value and the highest efficiency value. The considered generation temperature ranging from 70 °C to 95 °C is appropriate for low-grade energy sources assisting thermal cooling systems. After this system performance, come those in which R152a and R134a are employed, with isobutane and butane at the end. The obtained results represent potential design points of an efficient ejector cooling system operation, because to each combination of the above mentioned temperatures corresponds one and only one ejector geometry. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711000697 [article] Performance of ejector cooling systems using low ecological impact refrigerants = Performance des systèmes de refroidissement à éjecteur employant des frigorigènes exerçant un faible impact sur l'environnement [texte imprimé] / Raul Roman, Auteur ; Jorge I. Hernandez, Auteur . - 2011 . - pp. 1707-1716.
Génie Mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1707-1716
Mots-clés : Cooling Ejector system Performance Hydrocarbon R134a R152a Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : The theoretical behaviour of an ejector cooling system, using as working fluids propane, butane, isobutane, R152a and R134a, is obtained. The ejector works as a thermo-compressor that is simulated with a validated one-dimensional mathematical model, whose errors are lower than 6%. For a system unitary cooling capacity, a parametric study is carried out varying the generation, condensation and evaporation temperatures. From the obtained data, a complete analysis of the system performance can be achieved when the ejector and system operation parameters are considered. The best performance corresponds to the system using propane, because has the highest system coefficient of performance and its ejector has the maximum entrainment ratio value, the least area ratio value and the highest efficiency value. The considered generation temperature ranging from 70 °C to 95 °C is appropriate for low-grade energy sources assisting thermal cooling systems. After this system performance, come those in which R152a and R134a are employed, with isobutane and butane at the end. The obtained results represent potential design points of an efficient ejector cooling system operation, because to each combination of the above mentioned temperatures corresponds one and only one ejector geometry. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711000697
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1717-1723
Titre : An experimental investigation of an ejector for validating numerical simulations Titre original : Etude expérimentale et théorique sur un éjecteur destinée à valider des simulations numériques Type de document : texte imprimé Auteurs : David Scott, Auteur ; Aidoun, Zine, Auteur ; Ouzzane, Mohamed, Auteur Année de publication : 2011 Article en page(s) : pp. 1717-1723 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Ejector Test rig Experimentation Simulation R245fa Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : Supersonic ejectors have been used in cooling/refrigeration applications since the early 1900s. Interest in supersonic ejectors has been rekindled by recent efforts to reduce energy consumption; ejector refrigeration systems can be powered by solar energy or by waste heat generated by another process. This paper describes an experimental test bench using R245fa that was assembled and operated at CanmetENERGY in Varennes. The results from this test bench provide a source of reference data that may be used to validate numerical models of ejectors that could be used in refrigeration applications. Limited results from two numerical models are presented for comparison; global results from a 1D model and results from a detailed CFD model that show the flow field inside the ejector. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711001411 [article] An experimental investigation of an ejector for validating numerical simulations = Etude expérimentale et théorique sur un éjecteur destinée à valider des simulations numériques [texte imprimé] / David Scott, Auteur ; Aidoun, Zine, Auteur ; Ouzzane, Mohamed, Auteur . - 2011 . - pp. 1717-1723.
Génie Mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 34 N° 7 (Novembre 2011) . - pp. 1717-1723
Mots-clés : Ejector Test rig Experimentation Simulation R245fa Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : Supersonic ejectors have been used in cooling/refrigeration applications since the early 1900s. Interest in supersonic ejectors has been rekindled by recent efforts to reduce energy consumption; ejector refrigeration systems can be powered by solar energy or by waste heat generated by another process. This paper describes an experimental test bench using R245fa that was assembled and operated at CanmetENERGY in Varennes. The results from this test bench provide a source of reference data that may be used to validate numerical models of ejectors that could be used in refrigeration applications. Limited results from two numerical models are presented for comparison; global results from a 1D model and results from a detailed CFD model that show the flow field inside the ejector. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711001411
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