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International journal of refrigeration |
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Ajouter le résultat dans votre panierA review on application of carbonaceous materials and carbon matrix composites for heat exchangers and heat sinks / Q. Wang in International journal of refrigeration, Vol. 35 N° 1 (Janvier 2012)
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 7–26
Titre : A review on application of carbonaceous materials and carbon matrix composites for heat exchangers and heat sinks Titre original : Application des matériaux carbonés et des composites à matrice de carbone pour les échangeurs de chaleurs et les puits thermiques: synthèse Type de document : texte imprimé Auteurs : Q. Wang, Auteur ; X.H. Han, Auteur ; Y. Park, Auteur Année de publication : 2012 Article en page(s) : pp. 7–26 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Carbonaceous material Carbon matrix composite Graphite Heat exchanger Heat sink HVAC&R Résumé : Carbonaceous materials and carbon matrix composites (CAMCs) have potential to be used in heat exchangers and heat sinks for a number of thermal management applications related to HVAC&R systems, especially in high-temperature and corrosive environments. Recent developments in carbonaceous materials, such as new, natural graphite, carbon foam, carbon nanotubes, and CAMCs, open opportunities for new heat exchanger designs for compact and lightweight applications. The property data of various monolithic carbonaceous materials and CAMCs and their applications in liquid-to-liquid heat exchangers, liquid-to-gas heat exchangers, gas-to-gas heat exchangers and heat sinks are reviewed in this paper. While it is clear that these materials do hold promise for use in the construction of heat exchangers in different applications, additional research is still required in material properties, life-time behavior, structural design and manufacturing cost reduction. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002179 [article] A review on application of carbonaceous materials and carbon matrix composites for heat exchangers and heat sinks = Application des matériaux carbonés et des composites à matrice de carbone pour les échangeurs de chaleurs et les puits thermiques: synthèse [texte imprimé] / Q. Wang, Auteur ; X.H. Han, Auteur ; Y. Park, Auteur . - 2012 . - pp. 7–26.
Génie mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 7–26
Mots-clés : Carbonaceous material Carbon matrix composite Graphite Heat exchanger Heat sink HVAC&R Résumé : Carbonaceous materials and carbon matrix composites (CAMCs) have potential to be used in heat exchangers and heat sinks for a number of thermal management applications related to HVAC&R systems, especially in high-temperature and corrosive environments. Recent developments in carbonaceous materials, such as new, natural graphite, carbon foam, carbon nanotubes, and CAMCs, open opportunities for new heat exchanger designs for compact and lightweight applications. The property data of various monolithic carbonaceous materials and CAMCs and their applications in liquid-to-liquid heat exchangers, liquid-to-gas heat exchangers, gas-to-gas heat exchangers and heat sinks are reviewed in this paper. While it is clear that these materials do hold promise for use in the construction of heat exchangers in different applications, additional research is still required in material properties, life-time behavior, structural design and manufacturing cost reduction. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002179
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 27–35
Titre : Review on the experimental studies of refrigerant flow mechanisms inside short-tube orifices Titre original : Passage en revue des études expérimentales sur les mécanismes du débit du frigorigène dans les orifices de tubes courts Type de document : texte imprimé Auteurs : Kitti Nilpueng, Auteur ; Somchai Wongwises, Auteur Année de publication : 2012 Article en page(s) : pp. 27–35 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Expansion valve Flow rate Critical pressure Temperature variation Résumé : A short-tube orifice is a kind of an expansion device. The advantages of a short-tube orifice are simplicity, low cost, and low starting torque of the compressor as the pressures across the short-tube orifice equalise during the off-cycle. The two-phase flow mechanisms of refrigerant inside the short-tube orifice are very complicated although its physical configurations are simple. During the past decade, investigations of the mass flow rate of various refrigerants inside short-tube orifices, which is useful for selecting the proper size in practical applications, have been reported by many researchers. However, few researchers focused on the flow pattern, choked flow, and metastable flow phenomena inside short-tube orifices, which are necessary for a clear understanding of the flow behaviour and developing suitable calculation techniques. The aim of this paper is to summarise the evolution of the experimental research on refrigerant flow characteristics inside short-tube orifices to provide guidelines for future research. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002271 [article] Review on the experimental studies of refrigerant flow mechanisms inside short-tube orifices = Passage en revue des études expérimentales sur les mécanismes du débit du frigorigène dans les orifices de tubes courts [texte imprimé] / Kitti Nilpueng, Auteur ; Somchai Wongwises, Auteur . - 2012 . - pp. 27–35.
Génie mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 27–35
Mots-clés : Expansion valve Flow rate Critical pressure Temperature variation Résumé : A short-tube orifice is a kind of an expansion device. The advantages of a short-tube orifice are simplicity, low cost, and low starting torque of the compressor as the pressures across the short-tube orifice equalise during the off-cycle. The two-phase flow mechanisms of refrigerant inside the short-tube orifice are very complicated although its physical configurations are simple. During the past decade, investigations of the mass flow rate of various refrigerants inside short-tube orifices, which is useful for selecting the proper size in practical applications, have been reported by many researchers. However, few researchers focused on the flow pattern, choked flow, and metastable flow phenomena inside short-tube orifices, which are necessary for a clear understanding of the flow behaviour and developing suitable calculation techniques. The aim of this paper is to summarise the evolution of the experimental research on refrigerant flow characteristics inside short-tube orifices to provide guidelines for future research. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002271
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 36–46
Titre : Performance optimization of a Lorenz–Meutzner cycle charged with hydrocarbon mixtures for a domestic refrigerator-freezer Titre original : Réfrigérateur-congélateur domestique à cycle Lorenz-Meutzner, chargé avec un mélange d'hydrocarbures: Optimisation de la performance Type de document : texte imprimé Auteurs : Won Jae Yoon, Auteur ; Kookjeong Seo, Auteur ; Hyun Joon Chung, Auteur Année de publication : 2012 Article en page(s) : pp. 36–46 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Hydrocarbon Non-azeotropic mixture Performance Optimization Household refrigerator Résumé : A Lorenz–Meutzner cycle (called the “LM cycle”) for a domestic refrigerator-freezer (RF) has energy saving potential because of lower entropy generation in the fresh food compartment (R)-evaporator and lower compression ratio due to higher mean evaporating temperature, compared to a conventional cycle using pure refrigerant. In this study, a thermodynamic analysis for the optimum compositions of hydrocarbon (HC) mixtures and cycle specifications was performed. In addition, the effects of the refrigerant charge, capillary tube, compressor capacity, and mixture composition on the performance of the LM cycle using R-290/R-600 were investigated experimentally. Based on the experimental data, the energy consumption of the optimized LM cycle using R-290/R-600 (40:60%) was 11.2% lower than that of a bypass two-circuit cycle using R-600a in the same RF platform. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002301 [article] Performance optimization of a Lorenz–Meutzner cycle charged with hydrocarbon mixtures for a domestic refrigerator-freezer = Réfrigérateur-congélateur domestique à cycle Lorenz-Meutzner, chargé avec un mélange d'hydrocarbures: Optimisation de la performance [texte imprimé] / Won Jae Yoon, Auteur ; Kookjeong Seo, Auteur ; Hyun Joon Chung, Auteur . - 2012 . - pp. 36–46.
Génie mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 36–46
Mots-clés : Hydrocarbon Non-azeotropic mixture Performance Optimization Household refrigerator Résumé : A Lorenz–Meutzner cycle (called the “LM cycle”) for a domestic refrigerator-freezer (RF) has energy saving potential because of lower entropy generation in the fresh food compartment (R)-evaporator and lower compression ratio due to higher mean evaporating temperature, compared to a conventional cycle using pure refrigerant. In this study, a thermodynamic analysis for the optimum compositions of hydrocarbon (HC) mixtures and cycle specifications was performed. In addition, the effects of the refrigerant charge, capillary tube, compressor capacity, and mixture composition on the performance of the LM cycle using R-290/R-600 were investigated experimentally. Based on the experimental data, the energy consumption of the optimized LM cycle using R-290/R-600 (40:60%) was 11.2% lower than that of a bypass two-circuit cycle using R-600a in the same RF platform. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002301
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 47–57
Titre : The effect of refrigerant combinations on performance of a vapor compression refrigeration system with dedicated mechanical sub-cooling Titre original : Les effets de différentes combinaisons de frigorigènes sur la performance d' à compression de vapeur muni d'un dispositif de sous-refroidissement mécanique Type de document : texte imprimé Auteurs : Bilal Ahmed Qureshi, Auteur ; Syed M. Zubair, Auteur Année de publication : 2012 Article en page(s) : pp. 47–57 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Refrigeration system Refrigerant Subcooling Compressor Multistage system Résumé : Performance characteristics due to use of different refrigerant combinations in vapor compression cycles with dedicated mechanical sub-cooling are investigated. For scratch designs, R134a used in both cycles produced the best results in terms of COP, COP gain and relative compressor sizing. In retrofit cases, considering the high sensitivity of COP to the relative size of heat exchangers in the sub-cooler cycle and the low gain in COP obtained due to installation of a dedicated sub-cooling cycle when R717 is the main cycle refrigerant, it seems that dedicated mechanical sub-cooling may be more suited to cycles using R134a as the main cycle refrigerant rather than R717. With R134a as the main cycle refrigerant, no major difference was noted, by changing the sub-cooler cycle refrigerant, in the degradation of the performance parameters such as COP and cooling capacity, due to equal fouling of the heat exchangers. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002258 [article] The effect of refrigerant combinations on performance of a vapor compression refrigeration system with dedicated mechanical sub-cooling = Les effets de différentes combinaisons de frigorigènes sur la performance d' à compression de vapeur muni d'un dispositif de sous-refroidissement mécanique [texte imprimé] / Bilal Ahmed Qureshi, Auteur ; Syed M. Zubair, Auteur . - 2012 . - pp. 47–57.
Génie mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 47–57
Mots-clés : Refrigeration system Refrigerant Subcooling Compressor Multistage system Résumé : Performance characteristics due to use of different refrigerant combinations in vapor compression cycles with dedicated mechanical sub-cooling are investigated. For scratch designs, R134a used in both cycles produced the best results in terms of COP, COP gain and relative compressor sizing. In retrofit cases, considering the high sensitivity of COP to the relative size of heat exchangers in the sub-cooler cycle and the low gain in COP obtained due to installation of a dedicated sub-cooling cycle when R717 is the main cycle refrigerant, it seems that dedicated mechanical sub-cooling may be more suited to cycles using R134a as the main cycle refrigerant rather than R717. With R134a as the main cycle refrigerant, no major difference was noted, by changing the sub-cooler cycle refrigerant, in the degradation of the performance parameters such as COP and cooling capacity, due to equal fouling of the heat exchangers. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002258
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 58–67
Titre : Optimum cycle control of a two-stage injection heat pump with a double expansion sub-cooler Titre original : Régulation optimale du cycle d'une pompe à chaleur biétagée à injection munie d'un système de sous-refroidissement à deux détendeurs Type de document : texte imprimé Auteurs : Jaehyeok Heo, Auteur ; Hoon Kang, Auteur ; Yongchan Kim, Auteur Année de publication : 2012 Article en page(s) : pp. 58–67 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Heat pump Two-stage Injection Control Optimization Résumé : The refrigerant injection technique has rapidly developed in recent years due to its outstanding performance at low ambient temperatures, and various control methods for a heat pump with injection have been presented. However, most studies on cycle control have been theoretical, and practical control methods for cycle optimization based on experimental results hardly have been presented. In this study, an optimum cycle control method was proposed for a refrigerant injection heat pump with a double expansion sub-cooler based on the intermediate pressure and the injection ratio. The optimum sub-cooler pressure ratio was proposed from 0.4 to 0.7 in view of the heating capacity, and from 0.7 to 0.8 in view of the COP. The optimum injection ratio increased from 0.1 to 0.3 with an increase in the compression ratio. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002210 [article] Optimum cycle control of a two-stage injection heat pump with a double expansion sub-cooler = Régulation optimale du cycle d'une pompe à chaleur biétagée à injection munie d'un système de sous-refroidissement à deux détendeurs [texte imprimé] / Jaehyeok Heo, Auteur ; Hoon Kang, Auteur ; Yongchan Kim, Auteur . - 2012 . - pp. 58–67.
Génie mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 58–67
Mots-clés : Heat pump Two-stage Injection Control Optimization Résumé : The refrigerant injection technique has rapidly developed in recent years due to its outstanding performance at low ambient temperatures, and various control methods for a heat pump with injection have been presented. However, most studies on cycle control have been theoretical, and practical control methods for cycle optimization based on experimental results hardly have been presented. In this study, an optimum cycle control method was proposed for a refrigerant injection heat pump with a double expansion sub-cooler based on the intermediate pressure and the injection ratio. The optimum sub-cooler pressure ratio was proposed from 0.4 to 0.7 in view of the heating capacity, and from 0.7 to 0.8 in view of the COP. The optimum injection ratio increased from 0.1 to 0.3 with an increase in the compression ratio. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002210
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 68–78
Titre : Hybrid vapor compression refrigeration system with an integrated ejector cooling cycle Titre original : Système frigorifique à compression de vapeur à cycle de refroidissement à éjecteur intégré Type de document : texte imprimé Auteurs : Yinhai Zhu, Auteur ; Peixue Jiang, Auteur Année de publication : 2012 Article en page(s) : pp. 68–78 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Ejector Refrigeration Compression system Design Performance Résumé : A refrigeration system was developed which combines a basic vapor compression refrigeration cycle with an ejector cooling cycle. The ejector cooling cycle is driven by the waste heat from the condenser in the vapor compression refrigeration cycle. The additional cooling capacity from the ejector cycle is directly input into the evaporator of the vapor compression refrigeration cycle. The governing equations are derived based on energy and mass conservation in each component including the compressor, ejector, generator, booster and heat exchangers. The system performance is first analyzed for the on-design conditions. The results show that the COP is improved by 9.1% for R22 system. The system is then compared with a basic refrigeration system for variations of five important variables. The system analysis shows that this refrigeration system can effectively improve the COP by the ejector cycle with the refrigerant which has high compressor discharge temperature. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002192 [article] Hybrid vapor compression refrigeration system with an integrated ejector cooling cycle = Système frigorifique à compression de vapeur à cycle de refroidissement à éjecteur intégré [texte imprimé] / Yinhai Zhu, Auteur ; Peixue Jiang, Auteur . - 2012 . - pp. 68–78.
Génie mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 68–78
Mots-clés : Ejector Refrigeration Compression system Design Performance Résumé : A refrigeration system was developed which combines a basic vapor compression refrigeration cycle with an ejector cooling cycle. The ejector cooling cycle is driven by the waste heat from the condenser in the vapor compression refrigeration cycle. The additional cooling capacity from the ejector cycle is directly input into the evaporator of the vapor compression refrigeration cycle. The governing equations are derived based on energy and mass conservation in each component including the compressor, ejector, generator, booster and heat exchangers. The system performance is first analyzed for the on-design conditions. The results show that the COP is improved by 9.1% for R22 system. The system is then compared with a basic refrigeration system for variations of five important variables. The system analysis shows that this refrigeration system can effectively improve the COP by the ejector cycle with the refrigerant which has high compressor discharge temperature. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002192
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 79–87
Titre : The new thermo-ecological performance optimization of an irreversible three-heat-source absorption heat pump Titre original : Nouvelle optimisation thermo-écologique de la performance d'une pompe à chaleur irréversible à absorption munie de trois sources de chaleur Type de document : texte imprimé Auteurs : Paiguy Armand Ngouateu Wouagfack, Auteur ; Réné Tchinda, Auteur Année de publication : 2012 Article en page(s) : pp. 79–87 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Irreversibility Heat pump Absorption system Heat source Performance Environment Résumé : The new thermo-ecological performance optimization of an absorption heat pump operating between three temperature levels with the losses of heat resistance, internal irreversibility and leakage is analyzed by taking the ecological coefficient of performance (ECOP) as an objective function. The new thermo-ecological criterion takes into account the first and second law of thermodynamics and is defined as the heating rate per unit loss rate of availability. The ecological coefficient of performance has been expressed and maximized in terms of the temperatures of the working fluid in the main components of the system. The corresponding optimal temperatures and other optimum performance parameters have been derived analytically, and the effects of the internal irreversibility, the heat leakage coefficient and the source temperature ratio on the global and optimal performances are discussed. The obtained results may provide a general theoretical tool for the ecological design of absorption heat pumps. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002246 [article] The new thermo-ecological performance optimization of an irreversible three-heat-source absorption heat pump = Nouvelle optimisation thermo-écologique de la performance d'une pompe à chaleur irréversible à absorption munie de trois sources de chaleur [texte imprimé] / Paiguy Armand Ngouateu Wouagfack, Auteur ; Réné Tchinda, Auteur . - 2012 . - pp. 79–87.
Génie mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 79–87
Mots-clés : Irreversibility Heat pump Absorption system Heat source Performance Environment Résumé : The new thermo-ecological performance optimization of an absorption heat pump operating between three temperature levels with the losses of heat resistance, internal irreversibility and leakage is analyzed by taking the ecological coefficient of performance (ECOP) as an objective function. The new thermo-ecological criterion takes into account the first and second law of thermodynamics and is defined as the heating rate per unit loss rate of availability. The ecological coefficient of performance has been expressed and maximized in terms of the temperatures of the working fluid in the main components of the system. The corresponding optimal temperatures and other optimum performance parameters have been derived analytically, and the effects of the internal irreversibility, the heat leakage coefficient and the source temperature ratio on the global and optimal performances are discussed. The obtained results may provide a general theoretical tool for the ecological design of absorption heat pumps. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002246
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 88–97
Titre : First and second law investigation of waste heat based combined power and ejector-absorption refrigeration cycle Titre original : Etude fondée sur les premier et seconde principes d'un cycle frigorifique à éjecteur à absorption à récupération de chaleur utilisé en cogénération Type de document : texte imprimé Auteurs : Abdul Khaliq, Auteur ; Basant K. Agrawal, Auteur ; Rajesh Kumar, Auteur Année de publication : 2012 Article en page(s) : pp. 88–97 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Waste heat Power Refrigeration system Ejector Absorption Résumé : In the proposed cogeneration cycle, a LiBr–H2O absorption refrigeration system is employed to the combined power and ejector refrigeration system which uses R141b as a working fluid. Estimates for irreversibilities of individual components of the cycle lead to possible measures for performance improvement. Results of exergy distribution of waste heat in the cycle show that around 53.6% of the total input exergy is destroyed due to irreversibilities in the components, 22.7% is available as a useful exergy output, and 23.7% is exhaust exergy lost to the environment, whereas energy distribution shows 44% is exhaust energy and 19.7% is useful energy output. Results also show that proposed cogeneration cycle yields much better thermal and exergy efficiencies than the previously investigated combined power and ejector cooling cycle. Current investigation clearly show that the second law analysis is quantitatively visualizes losses within a cycle and gives clear trends for optimization. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711001940 [article] First and second law investigation of waste heat based combined power and ejector-absorption refrigeration cycle = Etude fondée sur les premier et seconde principes d'un cycle frigorifique à éjecteur à absorption à récupération de chaleur utilisé en cogénération [texte imprimé] / Abdul Khaliq, Auteur ; Basant K. Agrawal, Auteur ; Rajesh Kumar, Auteur . - 2012 . - pp. 88–97.
Génie mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 88–97
Mots-clés : Waste heat Power Refrigeration system Ejector Absorption Résumé : In the proposed cogeneration cycle, a LiBr–H2O absorption refrigeration system is employed to the combined power and ejector refrigeration system which uses R141b as a working fluid. Estimates for irreversibilities of individual components of the cycle lead to possible measures for performance improvement. Results of exergy distribution of waste heat in the cycle show that around 53.6% of the total input exergy is destroyed due to irreversibilities in the components, 22.7% is available as a useful exergy output, and 23.7% is exhaust exergy lost to the environment, whereas energy distribution shows 44% is exhaust energy and 19.7% is useful energy output. Results also show that proposed cogeneration cycle yields much better thermal and exergy efficiencies than the previously investigated combined power and ejector cooling cycle. Current investigation clearly show that the second law analysis is quantitatively visualizes losses within a cycle and gives clear trends for optimization. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711001940
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 98–114
Titre : A 2D hybrid model of the fluid flow and heat transfer in a reciprocating active magnetic regenerator Titre original : Modèle hybride bidimensionnel pour l'écoulement du fluide et le transfert de chaleur dans un régénérateur actif magnétique alternatif Type de document : texte imprimé Auteurs : Pablo A. Oliveira, Auteur ; Paulo V. Trevizoli, Auteur ; Jader R. Barbosa Jr., Auteur Année de publication : 2012 Article en page(s) : pp. 98–114 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Modelling Simulation Regenerator Magnetic refrigerator Cooling rate Thermal analysis Résumé : This paper evaluates the thermal behavior of a magnetic-Brayton-based parallel plate reciprocating active magnetic regenerator (AMR). A time-dependent, 2D model of the fluid flow and the coupled heat transfer between the working fluid and the solid refrigerant (gadolinium) is proposed. A hybrid calculation method which consists of an analytical solution for the flow and a numerical solution for the thermal field has been adopted. Results for the cooling capacity as a function of the temperature span and mass flow rate agree well with trends observed in experimental data and other theoretical models available in the literature. The volume of fluid displaced through the channels during the isofield processes influences significantly the AMR performance. For a cycle frequency of 1 Hz, the cycle-averaged cooling capacity reaches a maximum when the utilization factor is 0.1 and the displaced fluid volume equals 62% of the fluid volume of the AMR. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002118 [article] A 2D hybrid model of the fluid flow and heat transfer in a reciprocating active magnetic regenerator = Modèle hybride bidimensionnel pour l'écoulement du fluide et le transfert de chaleur dans un régénérateur actif magnétique alternatif [texte imprimé] / Pablo A. Oliveira, Auteur ; Paulo V. Trevizoli, Auteur ; Jader R. Barbosa Jr., Auteur . - 2012 . - pp. 98–114.
Génie mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 98–114
Mots-clés : Modelling Simulation Regenerator Magnetic refrigerator Cooling rate Thermal analysis Résumé : This paper evaluates the thermal behavior of a magnetic-Brayton-based parallel plate reciprocating active magnetic regenerator (AMR). A time-dependent, 2D model of the fluid flow and the coupled heat transfer between the working fluid and the solid refrigerant (gadolinium) is proposed. A hybrid calculation method which consists of an analytical solution for the flow and a numerical solution for the thermal field has been adopted. Results for the cooling capacity as a function of the temperature span and mass flow rate agree well with trends observed in experimental data and other theoretical models available in the literature. The volume of fluid displaced through the channels during the isofield processes influences significantly the AMR performance. For a cycle frequency of 1 Hz, the cycle-averaged cooling capacity reaches a maximum when the utilization factor is 0.1 and the displaced fluid volume equals 62% of the fluid volume of the AMR. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002118
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 115–121
Titre : Design of a new magnetic refrigeration field source running with rotating bar-shaped magnets Titre original : Conception d'une nouvelle source de champ pour les systèmes frigorifiques magnétiques constitués d'aimants tournants en forme de barres Type de document : texte imprimé Auteurs : H. R. E. H. Bouchekara, Auteur ; A. Kedous-Lebouc, Auteur ; J.-P. Yonnet, Auteur Année de publication : 2012 Article en page(s) : pp. 115–121 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Magnetic refrigerator Magnet Design Magnetic field Résumé : Magnetic refrigeration (MR) based on the magnetocaloric effect (MCE) is a prime candidate for the next generation of cooling systems. The essential components of magnetic refrigeration are the magnetic field generator and the magnetocaloric material. Although, several permanent magnet systems (magnetic field sources) for MR have been developed, recent development in magnetic refrigeration technology has encouraged researchers all over the world to think about new and original systems. This paper aims to describe a new and original magnetic refrigeration system based on a simple principle of magnetism called the Halbach effect. The proposed system is running with rotating bar-shaped magnets. This structure provides the desired varying magnetic field to the magnetocaloric material. Several configurations for the proposed systems have been investigated and presented in this paper. The design and modeling have been accomplished by using the finite elements method. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711001952 [article] Design of a new magnetic refrigeration field source running with rotating bar-shaped magnets = Conception d'une nouvelle source de champ pour les systèmes frigorifiques magnétiques constitués d'aimants tournants en forme de barres [texte imprimé] / H. R. E. H. Bouchekara, Auteur ; A. Kedous-Lebouc, Auteur ; J.-P. Yonnet, Auteur . - 2012 . - pp. 115–121.
Génie mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 115–121
Mots-clés : Magnetic refrigerator Magnet Design Magnetic field Résumé : Magnetic refrigeration (MR) based on the magnetocaloric effect (MCE) is a prime candidate for the next generation of cooling systems. The essential components of magnetic refrigeration are the magnetic field generator and the magnetocaloric material. Although, several permanent magnet systems (magnetic field sources) for MR have been developed, recent development in magnetic refrigeration technology has encouraged researchers all over the world to think about new and original systems. This paper aims to describe a new and original magnetic refrigeration system based on a simple principle of magnetism called the Halbach effect. The proposed system is running with rotating bar-shaped magnets. This structure provides the desired varying magnetic field to the magnetocaloric material. Several configurations for the proposed systems have been investigated and presented in this paper. The design and modeling have been accomplished by using the finite elements method. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711001952
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 122–129
Titre : Effects of storage on flow and heat transfer characteristics of ice slurry Titre original : Effets du stockage sur l'écoulement et les caractéristiques du transfert de chaleur d'un coulis de glace Type de document : texte imprimé Auteurs : Hiroyuki Kumano, Auteur ; Tetsuo Hirata, Auteur ; Yosuke Hagiwara, Auteur Année de publication : 2012 Article en page(s) : pp. 122–129 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Ice slurry Storage Pressure drop Heat transfer coefficient Laminar flow Turbulent flow Résumé : The effect of storage on flow and heat transfer characteristics of ice slurry was investigated experimentally. After ice slurry had been stored in the storage tank, variations in ice particle size were measured using a microscope, and diameter distribution and average diameter determined. The ice packing factor, Reynolds number and storage time were varied as experimental parameters. The pressure drop and heat transfer coefficient were measured when the ice slurry flowed in the horizontal tube. For laminar flow, the ratios of pipe friction and heat transfer coefficient decreased with storage time. For more than 12 h storage time, the ice slurry could not flow in the tube. The adhesion between ice particles seemed to cause a blockage in the tube. On the other hand, for turbulent flow, the pipe friction and ice slurry heat transfer coefficients were similar to that of the ethanol solution, and the storage effect was insignificant. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002209 [article] Effects of storage on flow and heat transfer characteristics of ice slurry = Effets du stockage sur l'écoulement et les caractéristiques du transfert de chaleur d'un coulis de glace [texte imprimé] / Hiroyuki Kumano, Auteur ; Tetsuo Hirata, Auteur ; Yosuke Hagiwara, Auteur . - 2012 . - pp. 122–129.
Génie mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 122–129
Mots-clés : Ice slurry Storage Pressure drop Heat transfer coefficient Laminar flow Turbulent flow Résumé : The effect of storage on flow and heat transfer characteristics of ice slurry was investigated experimentally. After ice slurry had been stored in the storage tank, variations in ice particle size were measured using a microscope, and diameter distribution and average diameter determined. The ice packing factor, Reynolds number and storage time were varied as experimental parameters. The pressure drop and heat transfer coefficient were measured when the ice slurry flowed in the horizontal tube. For laminar flow, the ratios of pipe friction and heat transfer coefficient decreased with storage time. For more than 12 h storage time, the ice slurry could not flow in the tube. The adhesion between ice particles seemed to cause a blockage in the tube. On the other hand, for turbulent flow, the pipe friction and ice slurry heat transfer coefficients were similar to that of the ethanol solution, and the storage effect was insignificant. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002209
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 130–141
Titre : Investigation of method for measuring adhesion force of ice in nano/micro scale by using SPM Titre original : Etude sur la méthode à employer pour mesurer le degré d’adhésion de la glace à l’échelle nano et micro à l’aide de la microscopie à balayage Type de document : texte imprimé Auteurs : Koji Matsumoto, Auteur ; Musashi Akaishi, Auteur ; Yoshikazu Teraoka, Auteur Année de publication : 2012 Article en page(s) : pp. 130–141 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Adhesion Ice Condensation Supercooling Surface tension Résumé : Ice adhesion to a cooling solid surface occurs in many situations, and it causes many serious problems that can lead to economic losses. Therefore, it is necessary to clarify the mechanism of ice adhesion to a cooling surface. In past studies, the adhesion force of ice was reported to be strongly governed by the surface energy of the cooling solid surface. In consideration of this surface energy, it is essential to investigate the ice adhesion force on a nano/micro scale. However, very little research has been conducted in nano/micro scale. Thus, in this paper, by using a scanning probe microscope (SPM), the methods for measuring the ice adhesion force and contact area between the cooling solid surface and formed ice are proposed, and the optimal measurement conditions of the SPM are determined. Then, the validity and effectiveness of the method are clarified. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002180 [article] Investigation of method for measuring adhesion force of ice in nano/micro scale by using SPM = Etude sur la méthode à employer pour mesurer le degré d’adhésion de la glace à l’échelle nano et micro à l’aide de la microscopie à balayage [texte imprimé] / Koji Matsumoto, Auteur ; Musashi Akaishi, Auteur ; Yoshikazu Teraoka, Auteur . - 2012 . - pp. 130–141.
Génie mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 130–141
Mots-clés : Adhesion Ice Condensation Supercooling Surface tension Résumé : Ice adhesion to a cooling solid surface occurs in many situations, and it causes many serious problems that can lead to economic losses. Therefore, it is necessary to clarify the mechanism of ice adhesion to a cooling surface. In past studies, the adhesion force of ice was reported to be strongly governed by the surface energy of the cooling solid surface. In consideration of this surface energy, it is essential to investigate the ice adhesion force on a nano/micro scale. However, very little research has been conducted in nano/micro scale. Thus, in this paper, by using a scanning probe microscope (SPM), the methods for measuring the ice adhesion force and contact area between the cooling solid surface and formed ice are proposed, and the optimal measurement conditions of the SPM are determined. Then, the validity and effectiveness of the method are clarified. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002180
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 142–149
Titre : The impact of geometric structure and flow arrangement on the performance of CO2 evaporators in multi-deck medium temperature display cabinets Titre original : L'impact de la structure géométrique et la configuration de l'écoulement sur la performance des évaporateurs au CO2 dans les meubles frigorifiques de vente polyétagés Type de document : texte imprimé Auteurs : Y.T. Ge, Auteur ; S.A. Tassou, Auteur Année de publication : 2012 Article en page(s) : pp. 142–149 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Carbon dioxide Display cabinets Evaporators Modelling Design Optimization Résumé : The CO2 refrigerant is widely applied in retail refrigeration systems to replace HFC fluids such as R404A, but its system performance requires further improvement. One feasible method would be to pinpoint the matching components of the system, in particular its evaporator coils. This paper focuses on the potential optimization of the CO2 evaporator design in an existing multi-deck medium temperature display cabinet charged previously with R404A refrigerant. To achieve this target, a display cabinet model with an integrated CFD and detailed evaporator sub models was utilized. This model could readily imitate the actual cabinet performance under varied operating conditions and component designs. Various design options of the CO2 cabinet evaporator were considered and their impacts on the cabinet performances were predicted by the integrated model. Ultimately, the optimized designs of CO2 cabinet evaporator coil geometries and refrigerant side operating parameters have been attained. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002234 [article] The impact of geometric structure and flow arrangement on the performance of CO2 evaporators in multi-deck medium temperature display cabinets = L'impact de la structure géométrique et la configuration de l'écoulement sur la performance des évaporateurs au CO2 dans les meubles frigorifiques de vente polyétagés [texte imprimé] / Y.T. Ge, Auteur ; S.A. Tassou, Auteur . - 2012 . - pp. 142–149.
Génie mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 142–149
Mots-clés : Carbon dioxide Display cabinets Evaporators Modelling Design Optimization Résumé : The CO2 refrigerant is widely applied in retail refrigeration systems to replace HFC fluids such as R404A, but its system performance requires further improvement. One feasible method would be to pinpoint the matching components of the system, in particular its evaporator coils. This paper focuses on the potential optimization of the CO2 evaporator design in an existing multi-deck medium temperature display cabinet charged previously with R404A refrigerant. To achieve this target, a display cabinet model with an integrated CFD and detailed evaporator sub models was utilized. This model could readily imitate the actual cabinet performance under varied operating conditions and component designs. Various design options of the CO2 cabinet evaporator were considered and their impacts on the cabinet performances were predicted by the integrated model. Ultimately, the optimized designs of CO2 cabinet evaporator coil geometries and refrigerant side operating parameters have been attained. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002234
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 150–159
Titre : QSPR prediction of surface tension of refrigerants from their molecular structures Titre original : Prévision QSPR (fondée sur la relation quantitative entre la structure et les propriétés) de la tension superficielle des frigorigènes à partir de leurs structures moléculaires Type de document : texte imprimé Auteurs : Aboozar Khajeh, Auteur ; Hamid Modarress, Auteur Année de publication : 2012 Article en page(s) : pp. 150–159 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Surface tension Refrigerant Structure Property Relationship Neuro-fuzzy inference system Résumé : In this work, quantitative structure-property relationship (QSPR) models for prediction of surface tension of 224 refrigerant compounds on the basis of their molecular structures were developed by using genetic function approximation (GFA) and adaptive neuro-fuzzy inference system (ANFIS) methods. GFA was used to select the most important molecular descriptors and develop the linear model. To develop a nonlinear model, the four descriptors selected by GFA were used as the inputs for ANFIS method. The predictive ability of the developed model was evaluated by predicting the surface tension of a number of compounds as a test set. The squared correlation coefficients of surface tension predicted by the GFA and ANFIS methods were 0.985 and 0.996, respectively. The final results suggest that the obtained QSPR model can be applied for predicting the surface tension of refrigerant compounds with high accuracy and simplicity. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711001964 [article] QSPR prediction of surface tension of refrigerants from their molecular structures = Prévision QSPR (fondée sur la relation quantitative entre la structure et les propriétés) de la tension superficielle des frigorigènes à partir de leurs structures moléculaires [texte imprimé] / Aboozar Khajeh, Auteur ; Hamid Modarress, Auteur . - 2012 . - pp. 150–159.
Génie mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 150–159
Mots-clés : Surface tension Refrigerant Structure Property Relationship Neuro-fuzzy inference system Résumé : In this work, quantitative structure-property relationship (QSPR) models for prediction of surface tension of 224 refrigerant compounds on the basis of their molecular structures were developed by using genetic function approximation (GFA) and adaptive neuro-fuzzy inference system (ANFIS) methods. GFA was used to select the most important molecular descriptors and develop the linear model. To develop a nonlinear model, the four descriptors selected by GFA were used as the inputs for ANFIS method. The predictive ability of the developed model was evaluated by predicting the surface tension of a number of compounds as a test set. The squared correlation coefficients of surface tension predicted by the GFA and ANFIS methods were 0.985 and 0.996, respectively. The final results suggest that the obtained QSPR model can be applied for predicting the surface tension of refrigerant compounds with high accuracy and simplicity. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711001964
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 160–170
Titre : Investigation on capacity matching in liquid desiccant and heat pump hybrid air-conditioning systems Titre original : Etude sur l’adaptation de la puissance des systèmes de conditionnement d’air hybrides à déshydratant liquide et à pompe à chaleur Type de document : texte imprimé Auteurs : Xiaofeng Niu, Auteur ; Fu Xiao, Auteur ; Zhenjun Ma, Auteur Année de publication : 2012 Article en page(s) : pp. 160–170 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Desiccant system Heat pump Compression system Heat balance Simulation Résumé : Liquid desiccant and heat pump (LDHP) hybrid air-conditioning system provides a promising independent air dehumidification solution. Capacity matching among the four major heat and mass transfer components, i.e. dehumidifier, regenerator, evaporator and condenser, is essentially important for energy efficiency of the hybrid system. In this paper, the configuration of the hybrid system is firstly studied. Novel matching indices are proposed to evaluate the matching effect. The results show that a LDHP hybrid system with double-condenser, one solution-cooled and one air-cooled, is a feasible configuration for achieving capacity matching. To achieve dynamic capacity matching under real changing operating conditions, the effects of three critical operating variables, including solution flow rate, revolution of the compressor and air flow rate in the air-cooled condenser, on capacity matching and energy performance are studied. Simulation results show that dynamic capacity matching can only be achieved by regulating these three operating variables simultaneously. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711001939 [article] Investigation on capacity matching in liquid desiccant and heat pump hybrid air-conditioning systems = Etude sur l’adaptation de la puissance des systèmes de conditionnement d’air hybrides à déshydratant liquide et à pompe à chaleur [texte imprimé] / Xiaofeng Niu, Auteur ; Fu Xiao, Auteur ; Zhenjun Ma, Auteur . - 2012 . - pp. 160–170.
Génie mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 160–170
Mots-clés : Desiccant system Heat pump Compression system Heat balance Simulation Résumé : Liquid desiccant and heat pump (LDHP) hybrid air-conditioning system provides a promising independent air dehumidification solution. Capacity matching among the four major heat and mass transfer components, i.e. dehumidifier, regenerator, evaporator and condenser, is essentially important for energy efficiency of the hybrid system. In this paper, the configuration of the hybrid system is firstly studied. Novel matching indices are proposed to evaluate the matching effect. The results show that a LDHP hybrid system with double-condenser, one solution-cooled and one air-cooled, is a feasible configuration for achieving capacity matching. To achieve dynamic capacity matching under real changing operating conditions, the effects of three critical operating variables, including solution flow rate, revolution of the compressor and air flow rate in the air-cooled condenser, on capacity matching and energy performance are studied. Simulation results show that dynamic capacity matching can only be achieved by regulating these three operating variables simultaneously. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711001939
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 171–186
Titre : Experimental investigation of the surface temperature and water retention effects on the frosting performance of a compact microchannel heat exchanger for heat pump systems Titre original : Etude expérimentale sur les effets de la température superficielle et de la rétention d'eau sur le givrage d'un échangeur de chaleur compact à microcanaux pour les systémes à pompe à chaleur Type de document : texte imprimé Auteurs : Ehsan Moallem, Auteur ; Sankar Padhmanabhan, Auteur ; Lorenzo Cremaschi, Auteur Année de publication : 2012 Article en page(s) : pp. 171–186 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Frost Microchannel Surface temperature Pressure drop Heat pump Capacity reduction Résumé : Frost formation on a louvered fin microchannel heat exchanger was experimentally investigated in this paper with the aim of determining the dominant factors affecting the time of frosting and frost growth rate. A novel methodology was developed to measure frost thickness and frost weight at intervals during the frosting period. Frost mass and thickness growth rates, corresponding coil heat transfer, capacity degradations and air pressure drop are measured and discussed. The experimental data showed that at a given air dry bulb temperature, the fin surface temperature and air humidity are the primary parameters that influence the frost growth rates. Water retention and air velocity had a secondary impact on the frosting performance. From digital images of the frost growth it was observed that frost does not nucleate from the water droplets retained in between fins but it developed from the leading edges of the fins. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S014070071100212X [article] Experimental investigation of the surface temperature and water retention effects on the frosting performance of a compact microchannel heat exchanger for heat pump systems = Etude expérimentale sur les effets de la température superficielle et de la rétention d'eau sur le givrage d'un échangeur de chaleur compact à microcanaux pour les systémes à pompe à chaleur [texte imprimé] / Ehsan Moallem, Auteur ; Sankar Padhmanabhan, Auteur ; Lorenzo Cremaschi, Auteur . - 2012 . - pp. 171–186.
Génie mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 171–186
Mots-clés : Frost Microchannel Surface temperature Pressure drop Heat pump Capacity reduction Résumé : Frost formation on a louvered fin microchannel heat exchanger was experimentally investigated in this paper with the aim of determining the dominant factors affecting the time of frosting and frost growth rate. A novel methodology was developed to measure frost thickness and frost weight at intervals during the frosting period. Frost mass and thickness growth rates, corresponding coil heat transfer, capacity degradations and air pressure drop are measured and discussed. The experimental data showed that at a given air dry bulb temperature, the fin surface temperature and air humidity are the primary parameters that influence the frost growth rates. Water retention and air velocity had a secondary impact on the frosting performance. From digital images of the frost growth it was observed that frost does not nucleate from the water droplets retained in between fins but it developed from the leading edges of the fins. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S014070071100212X
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 187–201
Titre : Temperature fluctuations and quality deterioration of chilled cod (Gadus morhua) fillets packaged in different boxes stored on pallets under dynamic temperature conditions Titre original : Fluctuations de température et altération de la qualité des filets de morue (Gadus Morhua) conditionnés dans différents types de caisse et entreposés sur des palettes sous différentes conditions de température dynamiques Type de document : texte imprimé Auteurs : Björn Margeirsson, Auteur ; Hélène L. Lauzon, Auteur ; Halldór Pálsson, Auteur Année de publication : 2012 Article en page(s) : pp. 187–201 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Fish Temperature variation Packaging Pallet Insulation Storage life Résumé : A study was carried out to evaluate temperature variation and quality deterioration of packaged cod fillets as influenced by the box type used and their position on pallets under dynamic temperature storage. Storage life of thermally abused fillets was compared to that of fillets stored at steady temperature. Thermal performance of fish boxes, made of corrugated plastic on one hand and expanded polystyrene on the other hand, was also compared. Fillet temperature at multiple positions on the pallets along with environmental temperature and humidity were monitored during storage. Differences in product temperature of up to 10.5 °C were recorded on the thermally abused pallets stored for 6.4 h at mean ambient temperature of 18.5 °C. A reduction in storage life of 1.5–3 days was observed depending on the box position on the abused pallets compared to steady temperature storage. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002222 [article] Temperature fluctuations and quality deterioration of chilled cod (Gadus morhua) fillets packaged in different boxes stored on pallets under dynamic temperature conditions = Fluctuations de température et altération de la qualité des filets de morue (Gadus Morhua) conditionnés dans différents types de caisse et entreposés sur des palettes sous différentes conditions de température dynamiques [texte imprimé] / Björn Margeirsson, Auteur ; Hélène L. Lauzon, Auteur ; Halldór Pálsson, Auteur . - 2012 . - pp. 187–201.
Génie mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 187–201
Mots-clés : Fish Temperature variation Packaging Pallet Insulation Storage life Résumé : A study was carried out to evaluate temperature variation and quality deterioration of packaged cod fillets as influenced by the box type used and their position on pallets under dynamic temperature storage. Storage life of thermally abused fillets was compared to that of fillets stored at steady temperature. Thermal performance of fish boxes, made of corrugated plastic on one hand and expanded polystyrene on the other hand, was also compared. Fillet temperature at multiple positions on the pallets along with environmental temperature and humidity were monitored during storage. Differences in product temperature of up to 10.5 °C were recorded on the thermally abused pallets stored for 6.4 h at mean ambient temperature of 18.5 °C. A reduction in storage life of 1.5–3 days was observed depending on the box position on the abused pallets compared to steady temperature storage. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002222
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 202–208
Titre : Portable forced-air tunnel evaluation for cooling products inside cold storage rooms Titre original : Evaluation d'un tunnel de refroidissement et de congélation pour le refroidissement de produits à l'intérieur de chambres froides utilisées pour l'entreposage Type de document : texte imprimé Auteurs : D. F. Barbin, Auteur ; L.C. Neves Filho, Auteur ; V. Silveira Júnior, Auteur Année de publication : 2012 Article en page(s) : pp. 202–208 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Frozen food Air distribution Refrigeration Freezing Heat transfer Résumé : Freezing process efficiency is affected by the required conditions to keep the air flow and temperature at the product surface. The objective of this work was to obtain results on comparative studies with air exhaustion and blowing using an experimental portable forced-air freezing tunnel. The device was designed to improve cooling rates inside storage room without the need for a cooling/freezing tunnel. A heterogeneity factor was proposed for air circulation evaluation and compared with convective heat transfer coefficient (hef) values. Lower modules of heterogeneity factor values represent smaller temperature differences among samples. Comparing two different air flow processes, heterogeneity factor values were similar for regions where the cooling air could flow without obstructions. However, larger differences were observed for regions with hampered air circulation. Results indicated that the air distribution, as well as the heat transfer, occurs more uniformly around the products in the exhausting process than in the blowing system. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002106 [article] Portable forced-air tunnel evaluation for cooling products inside cold storage rooms = Evaluation d'un tunnel de refroidissement et de congélation pour le refroidissement de produits à l'intérieur de chambres froides utilisées pour l'entreposage [texte imprimé] / D. F. Barbin, Auteur ; L.C. Neves Filho, Auteur ; V. Silveira Júnior, Auteur . - 2012 . - pp. 202–208.
Génie mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 202–208
Mots-clés : Frozen food Air distribution Refrigeration Freezing Heat transfer Résumé : Freezing process efficiency is affected by the required conditions to keep the air flow and temperature at the product surface. The objective of this work was to obtain results on comparative studies with air exhaustion and blowing using an experimental portable forced-air freezing tunnel. The device was designed to improve cooling rates inside storage room without the need for a cooling/freezing tunnel. A heterogeneity factor was proposed for air circulation evaluation and compared with convective heat transfer coefficient (hef) values. Lower modules of heterogeneity factor values represent smaller temperature differences among samples. Comparing two different air flow processes, heterogeneity factor values were similar for regions where the cooling air could flow without obstructions. However, larger differences were observed for regions with hampered air circulation. Results indicated that the air distribution, as well as the heat transfer, occurs more uniformly around the products in the exhausting process than in the blowing system. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002106
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 209–215
Titre : Can pipes be actually really that smooth? Titre original : Les tubes peuvent-ils être aussi lisses ? Type de document : texte imprimé Auteurs : Dejan Brkić, Auteur Année de publication : 2012 Article en page(s) : pp. 209–215 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Accuracy Comparison Flow rate Friction Hydraulics Piping Résumé : In some recent papers a few approximations to the implicit Nikuradse–Prandtl–Karman equation were shown. The Nikuradse–Prandtl–Karman equation for calculation of the hydraulic friction factor is valid for the hydraulically smooth regime of turbulence. Accuracy of these approximations for the friction factor in so called smooth pipes is checked and related problems from the hydraulics are analyzed in the spotlight of the recently developed equations. It can be concluded that pipes can be treated as smooth below certain value of the Reynolds number but after that even new polished pipes with a minor roughness follow the transitional and subsequently the rough law of flow at a higher values of the Reynolds number. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002283 [article] Can pipes be actually really that smooth? = Les tubes peuvent-ils être aussi lisses ? [texte imprimé] / Dejan Brkić, Auteur . - 2012 . - pp. 209–215.
Génie mécanique
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 35 N° 1 (Janvier 2012) . - pp. 209–215
Mots-clés : Accuracy Comparison Flow rate Friction Hydraulics Piping Résumé : In some recent papers a few approximations to the implicit Nikuradse–Prandtl–Karman equation were shown. The Nikuradse–Prandtl–Karman equation for calculation of the hydraulic friction factor is valid for the hydraulically smooth regime of turbulence. Accuracy of these approximations for the friction factor in so called smooth pipes is checked and related problems from the hydraulics are analyzed in the spotlight of the recently developed equations. It can be concluded that pipes can be treated as smooth below certain value of the Reynolds number but after that even new polished pipes with a minor roughness follow the transitional and subsequently the rough law of flow at a higher values of the Reynolds number. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002283
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