Documents disponibles écrits par cet auteur

Comparison of CO2 heat pump water heater performance with baseline cycle and two high COP cycles / Nicholas Fernandez in International journal of refrigeration, Vol. 33 N° 3 (Mai 2010) 

Public ISBD [article]  in International journal of refrigeration > Vol. 33 N° 3 (Mai 2010) . - pp. 635-644 Titre : Comparison of CO2 heat pump water heater performance with baseline cycle and two high COP cycles Titre original : Comparaison de la performance d'un système de chauffage d'eau à pompe à chaleur au CO2 et celle d'un cycle de base et celles de deux cycles au COP élevé Type de document : texte imprimé Auteurs : Nicholas Fernandez, Auteur ; Yunho Hwang, Auteur ; Reinhard Radermacher, Auteur Année de publication : 2010 Article en page(s) : pp. 635-644 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Heat  pump  Air–water  Carbon  dioxide  Transcritical  cycle  Review  Improvement  Performance  COP Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : A CO2 heat pump water heater breadboard facility was built and a performance evaluation was conducted to investigate the effect of ambient temperature and hot water temperature on the overall coefficient of performance (COP) during full tank heating tests in three scenarios typical of residential water heating. Results show that the overall COP was maximized at higher ambient temperatures and at lower hot water temperatures. The overall COP was 30% higher for heating a full tank of cold water than reheating a warm tank water after standby losses. Additionally, potential COP enhancements of two cycle options were investigated. Performance enhancement of the two-stage cycle with internal heat exchanger was found only for standby loss reheating at low ambient temperatures and was 7.5%, while that of the suction line heat exchanger cycle was up to 7.9% for initial tank water heating and around 3.4% for reheating a warm tank water. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700709002850 [article] Comparison of CO2 heat pump water heater performance with baseline cycle and two high COP cycles = Comparaison de la performance d'un système de chauffage d'eau à pompe à chaleur au CO2 et celle d'un cycle de base et celles de deux cycles au COP élevé [texte imprimé] / Nicholas Fernandez, Auteur ; Yunho Hwang, Auteur ; Reinhard Radermacher, Auteur . - 2010 . - pp. 635-644. Génie Mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 33 N° 3 (Mai 2010) . - pp. 635-644 Mots-clés : Heat  pump  Air–water  Carbon  dioxide  Transcritical  cycle  Review  Improvement  Performance  COP Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : A CO2 heat pump water heater breadboard facility was built and a performance evaluation was conducted to investigate the effect of ambient temperature and hot water temperature on the overall coefficient of performance (COP) during full tank heating tests in three scenarios typical of residential water heating. Results show that the overall COP was maximized at higher ambient temperatures and at lower hot water temperatures. The overall COP was 30% higher for heating a full tank of cold water than reheating a warm tank water after standby losses. Additionally, potential COP enhancements of two cycle options were investigated. Performance enhancement of the two-stage cycle with internal heat exchanger was found only for standby loss reheating at low ambient temperatures and was 7.5%, while that of the suction line heat exchanger cycle was up to 7.9% for initial tank water heating and around 3.4% for reheating a warm tank water. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700709002850

Experimental evaluation and performance enhancement prediction of desiccant assisted separate sensible and latent cooling air-conditioning system / Jiazhen Ling in International journal of refrigeration, Vol. 34 N° 4 (Juin 2011) 

Public ISBD [article]  in International journal of refrigeration > Vol. 34 N° 4 (Juin 2011) . - pp. 946-957 Titre : Experimental evaluation and performance enhancement prediction of desiccant assisted separate sensible and latent cooling air-conditioning system Titre original : Evaluation expérimentale et prévision de l'amélioration de la performance d'un système de conditionnement d'air à chaleur sensible et latente assisté d'un déshydratant séparé Type de document : texte imprimé Auteurs : Jiazhen Ling, Auteur ; Osamu Kuwabara, Auteur ; Yunho Hwang, Auteur Année de publication : 2011 Article en page(s) : pp. 946-957 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : CO2  Cooling  Desiccant  Heat  exchanger  Latent  heat  R410A  Sensible  heat Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : CO2 and R410A desiccant wheel (DW)-assisted separate sensible and latent cooling (SSLC) air-conditioning systems were tested under the AHRI standard. At a 50 °C regeneration temperature, the coefficient of performance (COP) of the vapor compression cycles improved only 7% from the respective baseline systems for both refrigerants. This paper proposed the idea of applying divided condensers (or gas coolers) to the R410A (or CO2) SSLC system to enhance its performance. It was found that the application of divided heat exchangers to the SSLC system provided sufficiently hot airflow for regenerating the desiccant wheel at both a reduced high side pressure (from 10.4 MPa to 9.7 MPa for CO2, from 3.46 MPa to 3.45 MPa for R410A) and a reduced discharge temperature from the condenser (gas cooler) (4 K lower for both refrigerants). The COP improvement is 36% and 61% to R410A and CO2 baseline systems, respectively. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002835 [article] Experimental evaluation and performance enhancement prediction of desiccant assisted separate sensible and latent cooling air-conditioning system = Evaluation expérimentale et prévision de l'amélioration de la performance d'un système de conditionnement d'air à chaleur sensible et latente assisté d'un déshydratant séparé [texte imprimé] / Jiazhen Ling, Auteur ; Osamu Kuwabara, Auteur ; Yunho Hwang, Auteur . - 2011 . - pp. 946-957. Génie Mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 34 N° 4 (Juin 2011) . - pp. 946-957 Mots-clés : CO2  Cooling  Desiccant  Heat  exchanger  Latent  heat  R410A  Sensible  heat Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : CO2 and R410A desiccant wheel (DW)-assisted separate sensible and latent cooling (SSLC) air-conditioning systems were tested under the AHRI standard. At a 50 °C regeneration temperature, the coefficient of performance (COP) of the vapor compression cycles improved only 7% from the respective baseline systems for both refrigerants. This paper proposed the idea of applying divided condensers (or gas coolers) to the R410A (or CO2) SSLC system to enhance its performance. It was found that the application of divided heat exchangers to the SSLC system provided sufficiently hot airflow for regenerating the desiccant wheel at both a reduced high side pressure (from 10.4 MPa to 9.7 MPa for CO2, from 3.46 MPa to 3.45 MPa for R410A) and a reduced discharge temperature from the condenser (gas cooler) (4 K lower for both refrigerants). The COP improvement is 36% and 61% to R410A and CO2 baseline systems, respectively. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002835

Performance comparison of R410A and R32 in vapor injection cycles / Xing Xu in International journal of refrigeration, Vol. 36 N° 3 (Mai 2013) 

Public ISBD [article]  in International journal of refrigeration > Vol. 36 N° 3 (Mai 2013) . - pp. 892–903 Titre : Performance comparison of R410A and R32 in vapor injection cycles Titre original : Comparaison de la performance du R410A et du R32 dans des cycles à injection de vapeur Type de document : texte imprimé Auteurs : Xing Xu, Auteur ; Yunho Hwang, Auteur ; Reinhard Radermacher, Auteur Année de publication : 2013 Article en page(s) : pp. 892–903 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : R410A;  R32;  Vapor;  Injection;  Heat  pump Résumé : As global warming has raised more critical concerns in recent years, refrigerants with high global warming potentials (GWP) are facing the challenges of being phased out. R410A, with a GWP of 2088, has been widely used in residential air-conditioner and heat pump systems. A potential substitute for R410A is R32, which has a GWP of 675. This paper investigates the performance difference using R410A and R32 in a vapor-injected heat pump system. Through experimentation, it was found that the capacity and coefficient of performance (COP) improvements using R32 can reach up to 10% and 9%, respectively, as compared to an identical cycle using R410A. It is concluded that R32 is an excellent alternative to replace R410A in terms of performance and can be further enhanced by component optimization. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712003532 [article] Performance comparison of R410A and R32 in vapor injection cycles = Comparaison de la performance du R410A et du R32 dans des cycles à injection de vapeur [texte imprimé] / Xing Xu, Auteur ; Yunho Hwang, Auteur ; Reinhard Radermacher, Auteur . - 2013 . - pp. 892–903. Refrigeration Langues : Anglais (eng) in International journal of refrigeration > Vol. 36 N° 3 (Mai 2013) . - pp. 892–903 Mots-clés : R410A;  R32;  Vapor;  Injection;  Heat  pump Résumé : As global warming has raised more critical concerns in recent years, refrigerants with high global warming potentials (GWP) are facing the challenges of being phased out. R410A, with a GWP of 2088, has been widely used in residential air-conditioner and heat pump systems. A potential substitute for R410A is R32, which has a GWP of 675. This paper investigates the performance difference using R410A and R32 in a vapor-injected heat pump system. Through experimentation, it was found that the capacity and coefficient of performance (COP) improvements using R32 can reach up to 10% and 9%, respectively, as compared to an identical cycle using R410A. It is concluded that R32 is an excellent alternative to replace R410A in terms of performance and can be further enhanced by component optimization. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712003532

Refrigerant injection for heat pumping/air conditioning systems: Literature review and challenges discussions / Xing Xu in International journal of refrigeration, Vol. 34 N° 2 (Mars 2011) 

Public ISBD [article]  in International journal of refrigeration > Vol. 34 N° 2 (Mars 2011) . - pp. 402-415 Titre : Refrigerant injection for heat pumping/air conditioning systems: Literature review and challenges discussions Titre original : Injection du frigorigène dans les systèmes à pompe à chaleur et de conditionnement d'air : passage en revue de la littérature et discussion sur les défis Type de document : texte imprimé Auteurs : Xing Xu, Auteur ; Yunho Hwang, Auteur ; Reinhard Radermacher, Auteur Année de publication : 2011 Article en page(s) : pp. 402-415 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Liquid  Vapor  Separation  Injection  Tank  Heat  exchanger Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : This paper reviews the major research on refrigerant injection techniques in detail. Liquid and vapor refrigerant injection techniques are discussed and compared. The current research on refrigerant injection techniques falls into two categories: system level research and component level research. The system level research is focused on low ambient temperature heating, heat pump water heating, high ambient temperature cooling, cycle comparison, and control strategy development. Internal heat exchanger and flash tank cycles are the two typical cycles for refrigerant injection. These two cycles are discussed and compared in detail. The component level research is focused on employing different types of compressors, variable speed compressors, the injection process, and the flash tank. Different types of compressors employing refrigerant injection are presented. Based on the literature study, the potential future research directions are presented and discussed. The flash tank cycle control strategy and refrigerant charge management strategy are worth further research efforts. Compressor design can be improved in order to optimize the performance with refrigerant injection. The appropriate design of flash tanks plays a vital role in achieving appropriate two-phase flow patterns in the flash tank. Computational Fluid Dynamics (CFD) modeling can be a useful tool to facilitate the design of the flash tank. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002239 [article] Refrigerant injection for heat pumping/air conditioning systems: Literature review and challenges discussions = Injection du frigorigène dans les systèmes à pompe à chaleur et de conditionnement d'air : passage en revue de la littérature et discussion sur les défis [texte imprimé] / Xing Xu, Auteur ; Yunho Hwang, Auteur ; Reinhard Radermacher, Auteur . - 2011 . - pp. 402-415. Génie Mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 34 N° 2 (Mars 2011) . - pp. 402-415 Mots-clés : Liquid  Vapor  Separation  Injection  Tank  Heat  exchanger Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : This paper reviews the major research on refrigerant injection techniques in detail. Liquid and vapor refrigerant injection techniques are discussed and compared. The current research on refrigerant injection techniques falls into two categories: system level research and component level research. The system level research is focused on low ambient temperature heating, heat pump water heating, high ambient temperature cooling, cycle comparison, and control strategy development. Internal heat exchanger and flash tank cycles are the two typical cycles for refrigerant injection. These two cycles are discussed and compared in detail. The component level research is focused on employing different types of compressors, variable speed compressors, the injection process, and the flash tank. Different types of compressors employing refrigerant injection are presented. Based on the literature study, the potential future research directions are presented and discussed. The flash tank cycle control strategy and refrigerant charge management strategy are worth further research efforts. Compressor design can be improved in order to optimize the performance with refrigerant injection. The appropriate design of flash tanks plays a vital role in achieving appropriate two-phase flow patterns in the flash tank. Computational Fluid Dynamics (CFD) modeling can be a useful tool to facilitate the design of the flash tank. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002239

Review of secondary loop refrigeration systems / Kai Wang in International journal of refrigeration, Vol. 33 N° 2 (Mars 2010) 

Public ISBD [article]  in International journal of refrigeration > Vol. 33 N° 2 (Mars 2010) . - pp. 212-234 Titre : Review of secondary loop refrigeration systems Titre original : Système frigorifiques à boucle secondaire: tour d’horizon Type de document : texte imprimé Auteurs : Kai Wang, Auteur ; Magnus Eisele, Auteur ; Yunho Hwang, Auteur Année de publication : 2011 Article en page(s) : pp. 212-234 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Refrigeration  system  Review  Distribution  Hydrocarbon  Secondary  refrigerant Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : Due to the environmental damage caused by HFC refrigerants, there is an increasing universal interest to research environmentally friendly fluids in refrigerants and alternative approaches to the traditional DX refrigeration system. These refrigerants include ammonia, carbon dioxide, hydrocarbon, R152a and HFO1234yf. Major drawbacks of these refrigerants are their potential flammability and safety hazards. One way to overcome this issue is to use the new refrigerants in conjunction with a secondary loop refrigeration system. Additional benefits of the secondary loop refrigeration system are refrigerant charges, leakage reduction, potential maintenance simplification, and low operating cost. This article presents a comprehensive review of the secondary loop refrigeration systems. Furthermore, this review covers the performance and risk assessment of flammable refrigerants, secondary refrigerants and components of the secondary loop refrigeration system within the following applications: commercial refrigeration, residential air conditioning/heat pumping, and mobile air conditioning. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700709002291 [article] Review of secondary loop refrigeration systems = Système frigorifiques à boucle secondaire: tour d’horizon [texte imprimé] / Kai Wang, Auteur ; Magnus Eisele, Auteur ; Yunho Hwang, Auteur . - 2011 . - pp. 212-234. Génie Mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 33 N° 2 (Mars 2010) . - pp. 212-234 Mots-clés : Refrigeration  system  Review  Distribution  Hydrocarbon  Secondary  refrigerant Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : Due to the environmental damage caused by HFC refrigerants, there is an increasing universal interest to research environmentally friendly fluids in refrigerants and alternative approaches to the traditional DX refrigeration system. These refrigerants include ammonia, carbon dioxide, hydrocarbon, R152a and HFO1234yf. Major drawbacks of these refrigerants are their potential flammability and safety hazards. One way to overcome this issue is to use the new refrigerants in conjunction with a secondary loop refrigeration system. Additional benefits of the secondary loop refrigeration system are refrigerant charges, leakage reduction, potential maintenance simplification, and low operating cost. This article presents a comprehensive review of the secondary loop refrigeration systems. Furthermore, this review covers the performance and risk assessment of flammable refrigerants, secondary refrigerants and components of the secondary loop refrigeration system within the following applications: commercial refrigeration, residential air conditioning/heat pumping, and mobile air conditioning. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700709002291

Theoretical study on separate sensible and latent cooling air-conditioning system / Jiazhen Ling in International journal of refrigeration, Vol. 33 N° 3 (Mai 2010) 

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Thermal and hydraulic performance of sinusoidal corrugated plate heat exchanger for low temperature lift heat pump / Hoseong Lee in International journal of refrigeration, Vol. 36 N° 3 (Mai 2013) 

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Transient and steady-state experimental investigation of flash tank vapor injection heat pump cycle control strategy / Xing Xu in International journal of refrigeration, Vol. 34 N° 8 (Décembre 2011) 

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