Les Inscriptions à la Bibliothèque sont ouvertes en
ligne via le site: https://biblio.enp.edu.dz
Les Réinscriptions se font à :
• La Bibliothèque Annexe pour les étudiants en
2ème Année CPST
• La Bibliothèque Centrale pour les étudiants en Spécialités
A partir de cette page vous pouvez :
| Retourner au premier écran avec les recherches... |
International journal of refrigeration |
Dépouillements
Ajouter le résultat dans votre panierDesiccant-assisted humidity control for air refrigeration cycles / C.E.L. Nóbrega in International journal of refrigeration, Vol. 36 N° 4 (Juin 2013)
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1183–1190
Titre : Desiccant-assisted humidity control for air refrigeration cycles Titre original : Cycles frigorifiques à air: régulation de l'humidité à l'aide d'un déshydratant Type de document : texte imprimé Auteurs : C.E.L. Nóbrega, Auteur ; L.A. Sphaier, Auteur Année de publication : 2013 Article en page(s) : pp. 1183–1190 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Desiccant dehumidification; Evaporative cooling; Air-conditioning; Thermal design; Hybrid cycle Résumé : A desiccant-assisted Brayton cooling cycle as an option for controlling humidity in air refrigeration cycles has been proposed. The modified cycle integrates a desiccant cooling cycle into an ordinary reversed Brayton cycle, using the heat rejection from the Brayton portion to drive the desiccant cooling portion, by applying a heat exchanger between the two cycles. Conversely, the cooling effect produced by the desiccant cycle is used to pre-cool the Brayton air stream, before it is admitted to the turbine. A mathematical model for the proposed cycle is developed, and its dynamic behavior is computationally simulated. The results show that the desiccant-assisted cycle can provide an effective humidity control, in addition to augmenting the cooling capacity of the cycle. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000182 [article] Desiccant-assisted humidity control for air refrigeration cycles = Cycles frigorifiques à air: régulation de l'humidité à l'aide d'un déshydratant [texte imprimé] / C.E.L. Nóbrega, Auteur ; L.A. Sphaier, Auteur . - 2013 . - pp. 1183–1190.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1183–1190
Mots-clés : Desiccant dehumidification; Evaporative cooling; Air-conditioning; Thermal design; Hybrid cycle Résumé : A desiccant-assisted Brayton cooling cycle as an option for controlling humidity in air refrigeration cycles has been proposed. The modified cycle integrates a desiccant cooling cycle into an ordinary reversed Brayton cycle, using the heat rejection from the Brayton portion to drive the desiccant cooling portion, by applying a heat exchanger between the two cycles. Conversely, the cooling effect produced by the desiccant cycle is used to pre-cool the Brayton air stream, before it is admitted to the turbine. A mathematical model for the proposed cycle is developed, and its dynamic behavior is computationally simulated. The results show that the desiccant-assisted cycle can provide an effective humidity control, in addition to augmenting the cooling capacity of the cycle. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000182
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1191–1202
Titre : Mini Vapor Cycle System for high density electronic cooling applications Titre original : Système à cycle à vapeur miniaturisé pour les applications de refroidissement dans le contexte d'une forte densité électronique Type de document : texte imprimé Auteurs : Simone Mancin, Auteur ; Claudio Zilio, Auteur ; Giulia Righetti, Auteur Année de publication : 2013 Article en page(s) : pp. 1191–1202 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Mini Vapor Cycle System; Electronic cooling; Aeronautical environment; Oil-free compressor Résumé : This paper reports the experimental analysis of a mini Vapor Cycle System (VCS) for electronic thermal management in avionic applications. The water cooled miniature scale refrigeration system uses R134a as working fluid and implements a new concept oil-free linear compressor prototype. In the range of operating test conditions investigated the pressure ratio varies from 1.54 to 3.75, the cooling capacity of the system varied from 37 W to 374 W, while the coefficient of performance (COP) ranged between 1.04 and 5.80. Particular attention was dedicated to the cold plate design, which had to meet the requirements established by aeronautical standards. The cold plate was equipped with 15 thermocouples in order to monitor the wall temperature distribution. The suitability and feasibility of the proposed cold plate for electronic thermal management in an aeronautical environment is critically discussed, based on the experimental results. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712003519 [article] Mini Vapor Cycle System for high density electronic cooling applications = Système à cycle à vapeur miniaturisé pour les applications de refroidissement dans le contexte d'une forte densité électronique [texte imprimé] / Simone Mancin, Auteur ; Claudio Zilio, Auteur ; Giulia Righetti, Auteur . - 2013 . - pp. 1191–1202.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1191–1202
Mots-clés : Mini Vapor Cycle System; Electronic cooling; Aeronautical environment; Oil-free compressor Résumé : This paper reports the experimental analysis of a mini Vapor Cycle System (VCS) for electronic thermal management in avionic applications. The water cooled miniature scale refrigeration system uses R134a as working fluid and implements a new concept oil-free linear compressor prototype. In the range of operating test conditions investigated the pressure ratio varies from 1.54 to 3.75, the cooling capacity of the system varied from 37 W to 374 W, while the coefficient of performance (COP) ranged between 1.04 and 5.80. Particular attention was dedicated to the cold plate design, which had to meet the requirements established by aeronautical standards. The cold plate was equipped with 15 thermocouples in order to monitor the wall temperature distribution. The suitability and feasibility of the proposed cold plate for electronic thermal management in an aeronautical environment is critically discussed, based on the experimental results. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712003519
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1203–1207
Titre : Performance of virtually non-flammable azeotropic HFO1234yf/HFC134a mixture for HFC134a applications Titre original : Performance du mélange azéotropique non inflammable HFO1234yf/HFC134a pour les applications du HFC134a Type de document : texte imprimé Auteurs : Yohan, Lee, Auteur ; Dong Gyu Kang, Auteur ; Dongsoo Jung, Auteur Année de publication : 2013 Article en page(s) : pp. 1203–1207 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Alternative refrigerant; HFO1234yf; HFC134a; HFO1234yf/HFC134a mixture; Mobile air-conditioner Résumé : In this study, ‘drop-in’ performance of HFC134a, HFO1234yf and HFO1234yf/HFC134a mixture at three compositions of 5%, 10%, and 15% HFC134a is measured in a heat pump bench tester under summer and winter conditions. Test results show that the COP, capacity, discharge temperature of HFO1234yf and HFO1234yf/HFC134a mixture are similar to those of HFC134a. For HFO1234yf/HFC134a mixture, flammability decreases as more HFC134a is added and at compositions of more than 10% of HFC134a, the mixture becomes non-flammable. The amount of charge for HFO1234yf and HFO1234yf/HFC134a mixture is up to 11% lower than that of HFC134a. Since HFO1234yf/HFC134a mixture with 10–11% HFC134a is virtually non-flammable and azeotropic and has no ODP and GWP of less than 150 meeting the requirement of European mobile air-conditioner directive, it can be used as an environmentally friendly solution for various HFC134a applications including mobile air-conditioners with minor modifications. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000388 [article] Performance of virtually non-flammable azeotropic HFO1234yf/HFC134a mixture for HFC134a applications = Performance du mélange azéotropique non inflammable HFO1234yf/HFC134a pour les applications du HFC134a [texte imprimé] / Yohan, Lee, Auteur ; Dong Gyu Kang, Auteur ; Dongsoo Jung, Auteur . - 2013 . - pp. 1203–1207.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1203–1207
Mots-clés : Alternative refrigerant; HFO1234yf; HFC134a; HFO1234yf/HFC134a mixture; Mobile air-conditioner Résumé : In this study, ‘drop-in’ performance of HFC134a, HFO1234yf and HFO1234yf/HFC134a mixture at three compositions of 5%, 10%, and 15% HFC134a is measured in a heat pump bench tester under summer and winter conditions. Test results show that the COP, capacity, discharge temperature of HFO1234yf and HFO1234yf/HFC134a mixture are similar to those of HFC134a. For HFO1234yf/HFC134a mixture, flammability decreases as more HFC134a is added and at compositions of more than 10% of HFC134a, the mixture becomes non-flammable. The amount of charge for HFO1234yf and HFO1234yf/HFC134a mixture is up to 11% lower than that of HFC134a. Since HFO1234yf/HFC134a mixture with 10–11% HFC134a is virtually non-flammable and azeotropic and has no ODP and GWP of less than 150 meeting the requirement of European mobile air-conditioner directive, it can be used as an environmentally friendly solution for various HFC134a applications including mobile air-conditioners with minor modifications. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000388
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1208–1219
Titre : Quantitative risk assessment of R290 in ice cream cabinets Titre original : Evaluation quantitative des risques associés à l'utilisation du R290 dans les meubles frigorifiques de vente utilisés pour les crèmes glacées Type de document : texte imprimé Auteurs : D. Colbourne, Auteur ; L. Espersen, Auteur Année de publication : 2013 Article en page(s) : pp. 1208–1219 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Hydrocarbon; Refrigerant; R290; Propane; Flammability; Risk analysis; Ignition Résumé : This study addresses the flammability risk of hydrocarbon (HC) refrigerants within horizontal type ice cream cabinets (ICC). Quantitative risk assessment (QRA) is used to estimate the likelihood of ignition of leaked refrigerant and severity of the consequences. Variables were evaluated including effect of room size, positioning of ICC, compressor compartment fan airflow and ignition source distribution. To strengthen the QRA, tests were carried out for refrigerant leakage and effects of ignition to validate dispersion and consequence models. Ignition frequency is between 1 × 10−8 and 2 × 10−13 per year. The maximum overpressure and thermal intensity within the room is 3 kPa and 200 s (kW m−2)4/3, respectively and 6.5 kPa and 20 s (kW m−2)4/3 from within the compressor compartment. The risks were found to be negligible compared to background and other reference values.
En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712002964 [article] Quantitative risk assessment of R290 in ice cream cabinets = Evaluation quantitative des risques associés à l'utilisation du R290 dans les meubles frigorifiques de vente utilisés pour les crèmes glacées [texte imprimé] / D. Colbourne, Auteur ; L. Espersen, Auteur . - 2013 . - pp. 1208–1219.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1208–1219
Mots-clés : Hydrocarbon; Refrigerant; R290; Propane; Flammability; Risk analysis; Ignition Résumé : This study addresses the flammability risk of hydrocarbon (HC) refrigerants within horizontal type ice cream cabinets (ICC). Quantitative risk assessment (QRA) is used to estimate the likelihood of ignition of leaked refrigerant and severity of the consequences. Variables were evaluated including effect of room size, positioning of ICC, compressor compartment fan airflow and ignition source distribution. To strengthen the QRA, tests were carried out for refrigerant leakage and effects of ignition to validate dispersion and consequence models. Ignition frequency is between 1 × 10−8 and 2 × 10−13 per year. The maximum overpressure and thermal intensity within the room is 3 kPa and 200 s (kW m−2)4/3, respectively and 6.5 kPa and 20 s (kW m−2)4/3 from within the compressor compartment. The risks were found to be negligible compared to background and other reference values.
En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712002964
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1220–1232
Titre : Theoretical and practical comparison of two-phase ejector refrigeration cycles including First and Second Law analysis Titre original : Comparaison théorique et pratique des cycles frigorifiques diphasiques à éjecteur, y compris à l'aide d'analyse fondée sur les premier et second principes Type de document : texte imprimé Auteurs : Neal, Lawrence, Auteur ; Stefan Elbel, Auteur Année de publication : 2013 Article en page(s) : pp. 1220–1232 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Ejector; Expansion work recovery; Throttling loss; Availability; Destruction; Cycle-comparison Résumé : This paper compares the standard two-phase ejector refrigeration cycle with a liquid–vapor separator to two alternate, less commonly considered two-phase ejector refrigeration cycles as well as to a conventional cycle with an expansion valve. An analytical comparison of the different ejector cycles' theoretical COP's is presented and used to show that they have the same theoretical COP. Numerical models are used to further compare the cycles in terms of theoretical COP and availability destruction. The results show that the standard two-phase ejector cycle has lower availability destruction and higher Second Law efficiency than the alternate ejector cycles despite having the same theoretical COP. Some advantages and disadvantages of the different ejector cycles that are not accounted for in the theoretical COP are discussed. The potential practical advantages offered by the alternate ejector cycles show that these and other alternate ejector cycles may be worth additional attention in future studies. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000625 [article] Theoretical and practical comparison of two-phase ejector refrigeration cycles including First and Second Law analysis = Comparaison théorique et pratique des cycles frigorifiques diphasiques à éjecteur, y compris à l'aide d'analyse fondée sur les premier et second principes [texte imprimé] / Neal, Lawrence, Auteur ; Stefan Elbel, Auteur . - 2013 . - pp. 1220–1232.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1220–1232
Mots-clés : Ejector; Expansion work recovery; Throttling loss; Availability; Destruction; Cycle-comparison Résumé : This paper compares the standard two-phase ejector refrigeration cycle with a liquid–vapor separator to two alternate, less commonly considered two-phase ejector refrigeration cycles as well as to a conventional cycle with an expansion valve. An analytical comparison of the different ejector cycles' theoretical COP's is presented and used to show that they have the same theoretical COP. Numerical models are used to further compare the cycles in terms of theoretical COP and availability destruction. The results show that the standard two-phase ejector cycle has lower availability destruction and higher Second Law efficiency than the alternate ejector cycles despite having the same theoretical COP. Some advantages and disadvantages of the different ejector cycles that are not accounted for in the theoretical COP are discussed. The potential practical advantages offered by the alternate ejector cycles show that these and other alternate ejector cycles may be worth additional attention in future studies. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000625
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1233–1242
Titre : Exergy analysis and optimization of R600a as a replacement of R134a in a domestic refrigerator system Titre original : Analyse exergétique et optimisation du R600a comme frigorigène de remplacement du R134a dans le système frigorifique d'un réfrigérateur domestique Type de document : texte imprimé Auteurs : Mahmood Mastani Joybari, Auteur ; Mohammad Sadegh Hatamipour, Auteur ; Amir Rahimi, Auteur Année de publication : 2013 Article en page(s) : pp. 1233–1242 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Exergy analysis; Taguchi experimental design; Domestic refrigerator; R134a; R600a Résumé : Exergy analysis was applied to investigate the performance of a domestic refrigerator originally manufactured to use 145 g of R134a. It was found that the highest exergy destruction occurred in the compressor followed by the condenser, capillary tube, evaporator, and superheating coil. Taguchi method was applied to design experiments to minimize exergy destruction while using R600a. Taguchi parameters were selected by the obtained results from R134a and an experiment using 60 g of R600a, which indicated similar results as R134a. Based on the outcomes, R600a charge amount, condenser fan rotational velocity and compressor coefficient of performance were selected for the design. The analysis of variance results indicated that R600a charge amount was the most effective parameter. At the optimum condition, the amount of charge required for R600a was 50 g, 66% lower than R134a one, which not only brings economic advantages, but also significantly reduces the risk of flammability of the hydrocarbon refrigerant.
En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000352 [article] Exergy analysis and optimization of R600a as a replacement of R134a in a domestic refrigerator system = Analyse exergétique et optimisation du R600a comme frigorigène de remplacement du R134a dans le système frigorifique d'un réfrigérateur domestique [texte imprimé] / Mahmood Mastani Joybari, Auteur ; Mohammad Sadegh Hatamipour, Auteur ; Amir Rahimi, Auteur . - 2013 . - pp. 1233–1242.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1233–1242
Mots-clés : Exergy analysis; Taguchi experimental design; Domestic refrigerator; R134a; R600a Résumé : Exergy analysis was applied to investigate the performance of a domestic refrigerator originally manufactured to use 145 g of R134a. It was found that the highest exergy destruction occurred in the compressor followed by the condenser, capillary tube, evaporator, and superheating coil. Taguchi method was applied to design experiments to minimize exergy destruction while using R600a. Taguchi parameters were selected by the obtained results from R134a and an experiment using 60 g of R600a, which indicated similar results as R134a. Based on the outcomes, R600a charge amount, condenser fan rotational velocity and compressor coefficient of performance were selected for the design. The analysis of variance results indicated that R600a charge amount was the most effective parameter. At the optimum condition, the amount of charge required for R600a was 50 g, 66% lower than R134a one, which not only brings economic advantages, but also significantly reduces the risk of flammability of the hydrocarbon refrigerant.
En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000352
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1243–1253
Titre : Cost optimization of heat exchanger inventory for mechanical subcooling refrigeration cycles Titre original : Optimisation du coût des échangeurs de chaleur utilisés pour les cycles de sous-refroidissement mécaniques Type de document : texte imprimé Auteurs : Bilal Ahmed Qureshi, Auteur ; Syed M. Zubair, Auteur Année de publication : 2013 Article en page(s) : pp. 1243–1253 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Thermoeconomic; Subcooling; Optimization; Heat exchanger; Inventory Résumé : In this paper, thermoeconomic considerations are given to heat exchanger inventory allocation in vapor compression cycles with mechanical subcooling. Investigation is made with respect to constant work rate, heat rejection and cooling rates as well as heat transfer in the subcooler. It was found that no minima exist for any of the cost functions with respect to the absolute temperature ratio (ξ) and the average subcooling absolute temperature ratio (θ3). The derivatives for the integrated subcooling cycle can be generated from the derivatives of the dedicated subcooling cycle. It was concluded that the cost optimization of the integrated mechanical subcooling system is qualitatively the same as the dedicated subcooling system. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000340 [article] Cost optimization of heat exchanger inventory for mechanical subcooling refrigeration cycles = Optimisation du coût des échangeurs de chaleur utilisés pour les cycles de sous-refroidissement mécaniques [texte imprimé] / Bilal Ahmed Qureshi, Auteur ; Syed M. Zubair, Auteur . - 2013 . - pp. 1243–1253.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1243–1253
Mots-clés : Thermoeconomic; Subcooling; Optimization; Heat exchanger; Inventory Résumé : In this paper, thermoeconomic considerations are given to heat exchanger inventory allocation in vapor compression cycles with mechanical subcooling. Investigation is made with respect to constant work rate, heat rejection and cooling rates as well as heat transfer in the subcooler. It was found that no minima exist for any of the cost functions with respect to the absolute temperature ratio (ξ) and the average subcooling absolute temperature ratio (θ3). The derivatives for the integrated subcooling cycle can be generated from the derivatives of the dedicated subcooling cycle. It was concluded that the cost optimization of the integrated mechanical subcooling system is qualitatively the same as the dedicated subcooling system. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000340
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1254–1262
Titre : Bus HVAC energy consumption test method based on HVAC unit behavior Titre original : Méthode d'essai pour déterminer la consommation d'énergie d'un système de chauffage, de ventilation et de conditionnement d'air d'un bus fondée sur le comportement du système Type de document : texte imprimé Auteurs : M. Hegar, Auteur ; M. Kolda, Auteur ; M. Kopecka, Auteur Année de publication : 2013 Article en page(s) : pp. 1254–1262 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Bus; HVAC unit; Input power; Standard engine; Fuel consumption; Test method Résumé : This paper presents a test method for determination of energy consumption of bus HVAC unit. The energy consumption corresponds to a bus engine fuel consumption increase during the HVAC unit operation period. The HVAC unit energy consumption is determined from the unit input power, which is measured under several levels of bus engine speeds and at different levels of testing heat load in the laboratory environment. Since the bus engine fuel consumption is incrementally induced by powering an HVAC unit, the results are subsequently recalculated to the unit fuel consumption under the defined road cycles in terms of standardized diesel engine. The method is likewise applicable either for classic or electric HVAC units with a main consumer (compressor or high voltage alternator) mechanically driven directly from the bus engine and also for electric HVAC units supplied from an alternative electric energy source in case of hybrid or fully electric buses. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712002836 [article] Bus HVAC energy consumption test method based on HVAC unit behavior = Méthode d'essai pour déterminer la consommation d'énergie d'un système de chauffage, de ventilation et de conditionnement d'air d'un bus fondée sur le comportement du système [texte imprimé] / M. Hegar, Auteur ; M. Kolda, Auteur ; M. Kopecka, Auteur . - 2013 . - pp. 1254–1262.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1254–1262
Mots-clés : Bus; HVAC unit; Input power; Standard engine; Fuel consumption; Test method Résumé : This paper presents a test method for determination of energy consumption of bus HVAC unit. The energy consumption corresponds to a bus engine fuel consumption increase during the HVAC unit operation period. The HVAC unit energy consumption is determined from the unit input power, which is measured under several levels of bus engine speeds and at different levels of testing heat load in the laboratory environment. Since the bus engine fuel consumption is incrementally induced by powering an HVAC unit, the results are subsequently recalculated to the unit fuel consumption under the defined road cycles in terms of standardized diesel engine. The method is likewise applicable either for classic or electric HVAC units with a main consumer (compressor or high voltage alternator) mechanically driven directly from the bus engine and also for electric HVAC units supplied from an alternative electric energy source in case of hybrid or fully electric buses. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712002836
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1263–1275
Titre : Periodical reverse flow and boiling fluctuations in a microchannel evaporator of an air-conditioning system Titre original : Ecoulement inverse périodique et fluctuations de l'ébullition dans l'évaporateur à microcanaux d'un système de conditionnement d'air Type de document : texte imprimé Auteurs : Hanfei Tuo, Auteur ; Pega Hrnjak, Auteur Année de publication : 2013 Article en page(s) : pp. 1263–1275 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Periodic reverse flow; Flow visualization; Boiling fluctuation; Microchannel evaporator Résumé : This paper presents the phenomenon of periodic reverse flow and associated boiling fluctuation found in experiments with a parallel microchannel evaporator used in an R134a air conditioning system. A simultaneous flow visualizations and measurements confirmed the periodic flow reversal. It caused synchronized oscillations of the evaporator inlet pressure and the pressure drop. The magnitude and frequency of oscillations increased with heat flux. Three potential impacts of flow reversal on evaporator performance are identified: 1) moderate liquid maldistribution; 2) reduced heat transfer coefficient; 3) increased refrigerant side pressure drop. Finally, to mitigate impacts of periodic reverse flow, a solution is proposed: to vent and bypass backflow vapor accumulated in the inlet header. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000236 [article] Periodical reverse flow and boiling fluctuations in a microchannel evaporator of an air-conditioning system = Ecoulement inverse périodique et fluctuations de l'ébullition dans l'évaporateur à microcanaux d'un système de conditionnement d'air [texte imprimé] / Hanfei Tuo, Auteur ; Pega Hrnjak, Auteur . - 2013 . - pp. 1263–1275.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1263–1275
Mots-clés : Periodic reverse flow; Flow visualization; Boiling fluctuation; Microchannel evaporator Résumé : This paper presents the phenomenon of periodic reverse flow and associated boiling fluctuation found in experiments with a parallel microchannel evaporator used in an R134a air conditioning system. A simultaneous flow visualizations and measurements confirmed the periodic flow reversal. It caused synchronized oscillations of the evaporator inlet pressure and the pressure drop. The magnitude and frequency of oscillations increased with heat flux. Three potential impacts of flow reversal on evaporator performance are identified: 1) moderate liquid maldistribution; 2) reduced heat transfer coefficient; 3) increased refrigerant side pressure drop. Finally, to mitigate impacts of periodic reverse flow, a solution is proposed: to vent and bypass backflow vapor accumulated in the inlet header. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000236
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1276–1284
Titre : Optimal control of the gas-cooler pressure of a CO2 heat pump using EEV opening and outdoor fan speed in the cooling mode Titre original : Régulation optimale de la pression du refroidisseur de gaz d'une pompe à chaleur au CO2 à l'aide de l'ouverture du détendeur électronique et de la vitesse du ventilateur externe, en mode refroidissement Type de document : texte imprimé Auteurs : Changhyun Baek, Auteur ; Jaehyeok Heo, Auteur ; Jongho Jung, Auteur Année de publication : 2013 Article en page(s) : pp. 1276–1284 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : CO2 heat pump; Gas-cooler pressure; Refrigerant charge; Electronic expansion valve opening; Outdoor fan speed; Compressor frequency Résumé : The objective of this study is to investigate the control methods of the gas-cooler pressure in a CO2 heat pump. The cooling performance of the CO2 heat pump was measured by varying the refrigerant charge amount, EEV opening, compressor frequency, and outdoor fan speed at various outdoor temperatures. The effects of the EEV opening and the outdoor fan speed on the gas-cooler pressure and the COP were analyzed by using the experimental data. In the standard cooling condition at the compressor frequency of 45 Hz, the optimum gas-cooler pressure and the maximum COP were 9200 kPa and 3.04, respectively, at the optimum EEV opening of 41% and outdoor fan speed of 500 rpm. As the compressor frequency increased from 45 Hz to 55 Hz at the standard cooling condition, the optimum outdoor fan speed increased from 500 rpm to 700 rpm.
En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000327 [article] Optimal control of the gas-cooler pressure of a CO2 heat pump using EEV opening and outdoor fan speed in the cooling mode = Régulation optimale de la pression du refroidisseur de gaz d'une pompe à chaleur au CO2 à l'aide de l'ouverture du détendeur électronique et de la vitesse du ventilateur externe, en mode refroidissement [texte imprimé] / Changhyun Baek, Auteur ; Jaehyeok Heo, Auteur ; Jongho Jung, Auteur . - 2013 . - pp. 1276–1284.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1276–1284
Mots-clés : CO2 heat pump; Gas-cooler pressure; Refrigerant charge; Electronic expansion valve opening; Outdoor fan speed; Compressor frequency Résumé : The objective of this study is to investigate the control methods of the gas-cooler pressure in a CO2 heat pump. The cooling performance of the CO2 heat pump was measured by varying the refrigerant charge amount, EEV opening, compressor frequency, and outdoor fan speed at various outdoor temperatures. The effects of the EEV opening and the outdoor fan speed on the gas-cooler pressure and the COP were analyzed by using the experimental data. In the standard cooling condition at the compressor frequency of 45 Hz, the optimum gas-cooler pressure and the maximum COP were 9200 kPa and 3.04, respectively, at the optimum EEV opening of 41% and outdoor fan speed of 500 rpm. As the compressor frequency increased from 45 Hz to 55 Hz at the standard cooling condition, the optimum outdoor fan speed increased from 500 rpm to 700 rpm.
En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000327
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1285–1293
Titre : Flow and heat transfer characteristics of ice slurries in a helically-coiled pipe Titre original : Caractéristiques de l'écoulement et du transfert de chaleur des coulis de glace à l'intérieur d'un tube hélicoïdal Type de document : texte imprimé Auteurs : Naoto Haruki, Auteur ; Akihiko Horibe, Auteur Année de publication : 2013 Article en page(s) : pp. 1285–1293 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Flow resistance; Heat transfer; Helically-coiled pipe; Ice slurry Résumé : Recently, ice slurry has attracted much attention due to its high energy efficiency and heat exchange ability. In this study, the flow and heat transfer characteristics of ice slurry in helically-coiled pipes of a dynamic ice-thermal storage system were investigated as a function of the ice packing factor, mean flow velocity, input heat flux, and coil radius. It was found that the flow resistance of ice slurry in helically-coiled pipes was influenced by the interaction between the buoyant force and the centrifugal force, due to secondary flow. In contrast, the heat transfer coefficient of ice slurry in helically-coiled pipes was influenced by the latent heat of the ice particles. Useful correlations for predicting the flow resistance and heat transfer coefficient of ice slurry were proposed in terms of several non-dimensional parameters. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000339 [article] Flow and heat transfer characteristics of ice slurries in a helically-coiled pipe = Caractéristiques de l'écoulement et du transfert de chaleur des coulis de glace à l'intérieur d'un tube hélicoïdal [texte imprimé] / Naoto Haruki, Auteur ; Akihiko Horibe, Auteur . - 2013 . - pp. 1285–1293.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1285–1293
Mots-clés : Flow resistance; Heat transfer; Helically-coiled pipe; Ice slurry Résumé : Recently, ice slurry has attracted much attention due to its high energy efficiency and heat exchange ability. In this study, the flow and heat transfer characteristics of ice slurry in helically-coiled pipes of a dynamic ice-thermal storage system were investigated as a function of the ice packing factor, mean flow velocity, input heat flux, and coil radius. It was found that the flow resistance of ice slurry in helically-coiled pipes was influenced by the interaction between the buoyant force and the centrifugal force, due to secondary flow. In contrast, the heat transfer coefficient of ice slurry in helically-coiled pipes was influenced by the latent heat of the ice particles. Useful correlations for predicting the flow resistance and heat transfer coefficient of ice slurry were proposed in terms of several non-dimensional parameters. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000339
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1294–1301
Titre : Rheological properties of CO2 hydrate slurry produced in a stirred tank reactor and a secondary refrigeration loop Titre original : Propriétés rhéologiques d'un coulis d'hydrate de CO2 produit dans un bac sous agitation et une boucle secondaire Type de document : texte imprimé Auteurs : Salem Jerbi, Auteur ; Anthony Delahaye, Auteur ; Jérémy Oignet, Auteur Année de publication : 2013 Article en page(s) : pp. 1294–1301 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Carbon dioxide hydrates; Phase change; Slurries; Rheology; Multiphase flow; Refrigeration Résumé : The aim of this paper is to present the rheological properties of CO2 hydrate slurry for a use as secondary fluids in refrigeration systems. A set-up composed of a stirred tank reactor and a circulation loop was used to study CO2 hydrate slurry formation and flowing. Rheological properties of CO2 hydrate slurries circulating in the loop were determined by the capillary viscometer method. The results show a shear thinning behaviour of the CO2 hydrate slurries for a solid fraction up to 22%. This behaviour is correlated by an Ostwald-de-Waele empirical equation, which takes into account the hydrate fraction of the slurry. The apparent viscosity of CO2 hydrate slurry was estimated from the model and a good agreement was found with the experimental data. A comparison with literature shows the importance of using a stirred reactor for slurry homogenisation, which allows the decrease of the apparent viscosity of the slurry. En ligne : http://www.sciencedirect.com/science/article/pii/S014070071200360X [article] Rheological properties of CO2 hydrate slurry produced in a stirred tank reactor and a secondary refrigeration loop = Propriétés rhéologiques d'un coulis d'hydrate de CO2 produit dans un bac sous agitation et une boucle secondaire [texte imprimé] / Salem Jerbi, Auteur ; Anthony Delahaye, Auteur ; Jérémy Oignet, Auteur . - 2013 . - pp. 1294–1301.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1294–1301
Mots-clés : Carbon dioxide hydrates; Phase change; Slurries; Rheology; Multiphase flow; Refrigeration Résumé : The aim of this paper is to present the rheological properties of CO2 hydrate slurry for a use as secondary fluids in refrigeration systems. A set-up composed of a stirred tank reactor and a circulation loop was used to study CO2 hydrate slurry formation and flowing. Rheological properties of CO2 hydrate slurries circulating in the loop were determined by the capillary viscometer method. The results show a shear thinning behaviour of the CO2 hydrate slurries for a solid fraction up to 22%. This behaviour is correlated by an Ostwald-de-Waele empirical equation, which takes into account the hydrate fraction of the slurry. The apparent viscosity of CO2 hydrate slurry was estimated from the model and a good agreement was found with the experimental data. A comparison with literature shows the importance of using a stirred reactor for slurry homogenisation, which allows the decrease of the apparent viscosity of the slurry. En ligne : http://www.sciencedirect.com/science/article/pii/S014070071200360X
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1302–1309
Titre : Investigation of the influence of surfactant on the degree of supercooling (coexisting system of solid–liquid and gas–liquid interfaces) Titre original : Etude sur l'influence de l'agent tensio-actif sur le degré de surrefroidissement (système où les interfaces solide/liquide et gaz/liquide coexistent) Type de document : texte imprimé Auteurs : Koji Matsumoto, Auteur ; Yoshito Igarashi, Auteur ; Daisuke Shirai, Auteur Année de publication : 2013 Article en page(s) : pp. 1302–1309 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Ice formation; Surfactant; Critical micelle concentration; Supercooling Résumé : In the ice formation process, supercooling, which results in COP degradation of the ice formation system, is avoidable. Thus, controlling supercooling dissolution would provide numerous benefits to the ice formation system. In order to control supercooling dissolution, we focus on the characteristics of hydrophilic surfactants. When hydrophilic surfactant is added to water, it is a great possibility that hydrophobic (lipophilic) surfactant molecules are adsorbed at gas–liquid and solid–liquid interfaces. Adsorption is assumed to affect supercooling dissolution. In the present study, in a coexisting system of solid–liquid and gas–liquid interfaces, a mixture of pure water and a small amount of hydrophilic surfactant is cooled in a test tube, the influence of the surfactant on the degree of supercooling of the mixture is clarified, and the tendencies of the degree of supercooling of the mixture above and below the critical micelle concentration are clarified. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000303 [article] Investigation of the influence of surfactant on the degree of supercooling (coexisting system of solid–liquid and gas–liquid interfaces) = Etude sur l'influence de l'agent tensio-actif sur le degré de surrefroidissement (système où les interfaces solide/liquide et gaz/liquide coexistent) [texte imprimé] / Koji Matsumoto, Auteur ; Yoshito Igarashi, Auteur ; Daisuke Shirai, Auteur . - 2013 . - pp. 1302–1309.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1302–1309
Mots-clés : Ice formation; Surfactant; Critical micelle concentration; Supercooling Résumé : In the ice formation process, supercooling, which results in COP degradation of the ice formation system, is avoidable. Thus, controlling supercooling dissolution would provide numerous benefits to the ice formation system. In order to control supercooling dissolution, we focus on the characteristics of hydrophilic surfactants. When hydrophilic surfactant is added to water, it is a great possibility that hydrophobic (lipophilic) surfactant molecules are adsorbed at gas–liquid and solid–liquid interfaces. Adsorption is assumed to affect supercooling dissolution. In the present study, in a coexisting system of solid–liquid and gas–liquid interfaces, a mixture of pure water and a small amount of hydrophilic surfactant is cooled in a test tube, the influence of the surfactant on the degree of supercooling of the mixture is clarified, and the tendencies of the degree of supercooling of the mixture above and below the critical micelle concentration are clarified. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000303
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp.1310–1318
Titre : Experimental investigation of the temperatures and performance of a commercial ice-storage tank Titre original : Etude expérimentale sur les températures et la performance d'un bac à accumulation de glace commercial Type de document : texte imprimé Auteurs : A. López-Navarro, Auteur ; J. Biosca-Taronger, Auteur ; B. Torregrosa-Jaime, Auteur Année de publication : 2013 Article en page(s) : pp.1310–1318 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Thermal storage; Experimental installation; Ice formation; Energy consumption Résumé : This paper presents the results of an experimental installation with an internal melt-ice-on-coil tank which has a total capacity of 172 kWh. The aim of this work is to analyse the freezing process in a tank with counter-current spiral-shaped coils immersed in around 1855l water. An experimental campaign has been performed with different inlet temperatures and mass flow rates of the heat transfer fluid. This study analyses (i) the chiller performance, (ii) the ice-formation process and (iii) the energy consumption of the installation. Supply temperatures between −2.5 °C and −5.2 °C have been sufficient to charge the tank without using any nucleating agents. The lowest energy consumption has been achieved for the fastest charging tests. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712002332 [article] Experimental investigation of the temperatures and performance of a commercial ice-storage tank = Etude expérimentale sur les températures et la performance d'un bac à accumulation de glace commercial [texte imprimé] / A. López-Navarro, Auteur ; J. Biosca-Taronger, Auteur ; B. Torregrosa-Jaime, Auteur . - 2013 . - pp.1310–1318.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp.1310–1318
Mots-clés : Thermal storage; Experimental installation; Ice formation; Energy consumption Résumé : This paper presents the results of an experimental installation with an internal melt-ice-on-coil tank which has a total capacity of 172 kWh. The aim of this work is to analyse the freezing process in a tank with counter-current spiral-shaped coils immersed in around 1855l water. An experimental campaign has been performed with different inlet temperatures and mass flow rates of the heat transfer fluid. This study analyses (i) the chiller performance, (ii) the ice-formation process and (iii) the energy consumption of the installation. Supply temperatures between −2.5 °C and −5.2 °C have been sufficient to charge the tank without using any nucleating agents. The lowest energy consumption has been achieved for the fastest charging tests. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712002332
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1319–1326
Titre : Modeling heat and mass transfer during vacuum freezing of puree droplet Titre original : Modélisation du transfert de chaleur et de masse lors de la congélation sous vide d'une gouttelette de purée Type de document : texte imprimé Auteurs : C. Cogné, Auteur ; P.U. Nguyen, Auteur ; J.L. Lanoisellé, Auteur Année de publication : 2013 Article en page(s) : pp. 1319–1326 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Freezing; Vacuum; Modeling; Heat transfer; Mass transfer; Puree Résumé : A numerical simulation using COMSOL®, a commercial software, has been developed to model heat and mass transfer during vacuum freezing by evaporation of a single puree droplet. The simulations predict local water content, temperature and mass losses during the process. This theoretical model, based on the numerical resolution of heat and mass diffusion equations, includes both the process conditions and the thermophysical properties of the puree. Experimental temperature profiles and dry matter content measurements were used to validate the model and assess its accuracy. From the model, it has been shown that the main parameters that governed the transfer are the droplet diameter, the ambient pressure and the initial temperature. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000261 [article] Modeling heat and mass transfer during vacuum freezing of puree droplet = Modélisation du transfert de chaleur et de masse lors de la congélation sous vide d'une gouttelette de purée [texte imprimé] / C. Cogné, Auteur ; P.U. Nguyen, Auteur ; J.L. Lanoisellé, Auteur . - 2013 . - pp. 1319–1326.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1319–1326
Mots-clés : Freezing; Vacuum; Modeling; Heat transfer; Mass transfer; Puree Résumé : A numerical simulation using COMSOL®, a commercial software, has been developed to model heat and mass transfer during vacuum freezing by evaporation of a single puree droplet. The simulations predict local water content, temperature and mass losses during the process. This theoretical model, based on the numerical resolution of heat and mass diffusion equations, includes both the process conditions and the thermophysical properties of the puree. Experimental temperature profiles and dry matter content measurements were used to validate the model and assess its accuracy. From the model, it has been shown that the main parameters that governed the transfer are the droplet diameter, the ambient pressure and the initial temperature. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000261
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1327–1332
Titre : An accurate generalized model for predict vapor pressure of refrigerants Titre original : Modèle précis et général pour la prévision de la pression de vapeur des frigorigènes Type de document : texte imprimé Auteurs : Ehsan Sanjari, Auteur ; Mehrdad Honarmand, Auteur ; Hamidreza Badihi, Auteur Année de publication : 2013 Article en page(s) : pp. 1327–1332 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Vapor pressure; Refrigerant; Predictive model; Universal method Résumé : The examination of the available vapor pressure data in the case of the methane, ethane, propane and butane halogenated refrigerants, allowed the derivation and recommendation of standard equations for this property. In this study a new universal substance-independent equation for vapor pressure as a function of reduced temperature, critical pressure, and acentric factor has been developed to estimate vapor pressures of refrigerants. With the presented model, vapor pressures have been calculated and compared with the data reported in data compilation for 28 refrigerants for 5600 data points, and the overall average absolute percentage deviation is only 0.52%. The accuracy of obtained model has been compared to the mostly used predictive models and the comparison indicates that the proposed method provide more accurate results than other methods used in this work. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000224 [article] An accurate generalized model for predict vapor pressure of refrigerants = Modèle précis et général pour la prévision de la pression de vapeur des frigorigènes [texte imprimé] / Ehsan Sanjari, Auteur ; Mehrdad Honarmand, Auteur ; Hamidreza Badihi, Auteur . - 2013 . - pp. 1327–1332.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1327–1332
Mots-clés : Vapor pressure; Refrigerant; Predictive model; Universal method Résumé : The examination of the available vapor pressure data in the case of the methane, ethane, propane and butane halogenated refrigerants, allowed the derivation and recommendation of standard equations for this property. In this study a new universal substance-independent equation for vapor pressure as a function of reduced temperature, critical pressure, and acentric factor has been developed to estimate vapor pressures of refrigerants. With the presented model, vapor pressures have been calculated and compared with the data reported in data compilation for 28 refrigerants for 5600 data points, and the overall average absolute percentage deviation is only 0.52%. The accuracy of obtained model has been compared to the mostly used predictive models and the comparison indicates that the proposed method provide more accurate results than other methods used in this work. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000224
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1333–1340
Titre : Viscosity and density of aluminum oxide nanolubricant Titre original : Viscosité et masse volumique d'un nanolubrifiant à base d'oxyde d'aluminium Type de document : texte imprimé Auteurs : Mark A. Kedzierski, Auteur Année de publication : 2013 Article en page(s) : pp. 1333–1340 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Colloidal suspension; Density; Lubricant; Viscosity; Water chiller Résumé : This paper presents liquid kinematic viscosity and density measurements of a synthetic polyolester-based aluminum oxide (Al2O3) nanoparticle dispersion (nanolubricant) at atmospheric pressure over the temperature range 288 K–318 K. Two Al2O3 particles diameters were investigated: approximately 60 nm and 10 nm. A good dispersion of the spherical nanoparticles in the lubricant was maintained with a surfactant. Viscosity and density measurements were made for the neat lubricant along with twelve nanolubricants with differing nanoparticle and surfactant mass fractions. A new model was developed to predict the kinematic viscosity of the nanolubricant by summing the viscosities of the nanoparticle, the surfactant and the base lubricant. The resulting correlated model for the liquid kinematic viscosity was a function of temperature, nanoparticle mass fraction, surfactant mass fraction, and nanoparticle diameter. The measurements are important for the design of nanolubricants for heat transfer and flow applications. En ligne : http://www.sciencedirect.com/science/article/pii/S014070071300056X [article] Viscosity and density of aluminum oxide nanolubricant = Viscosité et masse volumique d'un nanolubrifiant à base d'oxyde d'aluminium [texte imprimé] / Mark A. Kedzierski, Auteur . - 2013 . - pp. 1333–1340.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1333–1340
Mots-clés : Colloidal suspension; Density; Lubricant; Viscosity; Water chiller Résumé : This paper presents liquid kinematic viscosity and density measurements of a synthetic polyolester-based aluminum oxide (Al2O3) nanoparticle dispersion (nanolubricant) at atmospheric pressure over the temperature range 288 K–318 K. Two Al2O3 particles diameters were investigated: approximately 60 nm and 10 nm. A good dispersion of the spherical nanoparticles in the lubricant was maintained with a surfactant. Viscosity and density measurements were made for the neat lubricant along with twelve nanolubricants with differing nanoparticle and surfactant mass fractions. A new model was developed to predict the kinematic viscosity of the nanolubricant by summing the viscosities of the nanoparticle, the surfactant and the base lubricant. The resulting correlated model for the liquid kinematic viscosity was a function of temperature, nanoparticle mass fraction, surfactant mass fraction, and nanoparticle diameter. The measurements are important for the design of nanolubricants for heat transfer and flow applications. En ligne : http://www.sciencedirect.com/science/article/pii/S014070071300056X
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1341–1346
Titre : Measurements of saturated densities and critical parameters for the binary mixture of 2,3,3,3-tetrafluoropropene (R-1234yf) + difluoromethane (R-32) Titre original : Mesures des masses volumiques saturées et paramètres critiques d'un mélange binaire de 2,3,3,3-tétrafluoropropène (R-1234yf) + difluorométhane (R-32) Type de document : texte imprimé Auteurs : Ryo Akasaka, Auteur ; Katsuyuki Tanaka, Auteur ; Yukihiro Higashi, Auteur Année de publication : 2013 Article en page(s) : pp. 1341–1346 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Critical density; Critical point; Critical pressure; Critical temperature; R-1234yf + R-32 mixture Résumé : The vapor–liquid coexistence curves near the critical point of the binary mixture of 2,3,3,3-tetrafluoropropene (R-1234yf) + difluoromethane (R-32) were measured by means of the visual observation of meniscus disappearance. Eleven, eighteen, and eleven saturated densities were obtained for mixtures with 50.00 mass%, 80.01 mass%, and 90.00 mass% of R-1234yf, respectively. The critical temperatures, critical densities, and critical molar volumes of the mixtures were determined from the meniscus disappearing level and the intensity of the critical opalescence. The critical pressures of the mixtures were also determined from the analysis of pρTx measurements. The composition dependence of the critical parameters was formulated with simple correlations. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000285 [article] Measurements of saturated densities and critical parameters for the binary mixture of 2,3,3,3-tetrafluoropropene (R-1234yf) + difluoromethane (R-32) = Mesures des masses volumiques saturées et paramètres critiques d'un mélange binaire de 2,3,3,3-tétrafluoropropène (R-1234yf) + difluorométhane (R-32) [texte imprimé] / Ryo Akasaka, Auteur ; Katsuyuki Tanaka, Auteur ; Yukihiro Higashi, Auteur . - 2013 . - pp. 1341–1346.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1341–1346
Mots-clés : Critical density; Critical point; Critical pressure; Critical temperature; R-1234yf + R-32 mixture Résumé : The vapor–liquid coexistence curves near the critical point of the binary mixture of 2,3,3,3-tetrafluoropropene (R-1234yf) + difluoromethane (R-32) were measured by means of the visual observation of meniscus disappearance. Eleven, eighteen, and eleven saturated densities were obtained for mixtures with 50.00 mass%, 80.01 mass%, and 90.00 mass% of R-1234yf, respectively. The critical temperatures, critical densities, and critical molar volumes of the mixtures were determined from the meniscus disappearing level and the intensity of the critical opalescence. The critical pressures of the mixtures were also determined from the analysis of pρTx measurements. The composition dependence of the critical parameters was formulated with simple correlations. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000285
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1347–1368
Titre : Experimental study of the thermal conductivity of ammonia + water refrigerant mixtures at temperatures from 278 K to 356 K and at pressures up to 20 MPa Titre original : Etude expérimentale sur la conductivité thermique des mélanges ammoniac/eau à des températures entre 278 et 356 K et des pressions allant jusqu'à 20 MPa Type de document : texte imprimé Auteurs : F.N. Shamsetdinov, Auteur ; Z. I. Zaripov, Auteur ; I. M. Abdulagatov, Auteur Année de publication : 2013 Article en page(s) : pp. 1347–1368 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Ammonia; Ammonia–water; Correlation models; Thermal conductivity; Water Résumé : The thermal conductivity of binary ammonia + water mixtures was measured over the temperature range from 278 K to 356 K and at pressures to 20 MPa using the steady-state hot-wire method. Measurements were made for ten compositions over the entire concentration range from 0 to 1 mole fraction of ammonia, namely, 0.0, 0.1905, 0.2683, 0.3002, 0.4990, 0.5030, 0.6704, 0.7832, 0.9178, and 1.0 mole fraction of ammonia. In total, 316 experimental data points were obtained. The expanded uncertainty, with a coverage factor of k = 2, of the thermal conductivity, pressure, temperature, and concentration measurements is estimated to be 3%, 0.05%, 0.02 K, and 0.0014%, respectively. The average absolute deviation (AAD) between the measured and calculated reference values for pure water and ammonia is 1.3% and 1.4%, respectively. Correlation models for the thermal conductivity of liquid ammonia + water mixtures were also developed. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000315 [article] Experimental study of the thermal conductivity of ammonia + water refrigerant mixtures at temperatures from 278 K to 356 K and at pressures up to 20 MPa = Etude expérimentale sur la conductivité thermique des mélanges ammoniac/eau à des températures entre 278 et 356 K et des pressions allant jusqu'à 20 MPa [texte imprimé] / F.N. Shamsetdinov, Auteur ; Z. I. Zaripov, Auteur ; I. M. Abdulagatov, Auteur . - 2013 . - pp. 1347–1368.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1347–1368
Mots-clés : Ammonia; Ammonia–water; Correlation models; Thermal conductivity; Water Résumé : The thermal conductivity of binary ammonia + water mixtures was measured over the temperature range from 278 K to 356 K and at pressures to 20 MPa using the steady-state hot-wire method. Measurements were made for ten compositions over the entire concentration range from 0 to 1 mole fraction of ammonia, namely, 0.0, 0.1905, 0.2683, 0.3002, 0.4990, 0.5030, 0.6704, 0.7832, 0.9178, and 1.0 mole fraction of ammonia. In total, 316 experimental data points were obtained. The expanded uncertainty, with a coverage factor of k = 2, of the thermal conductivity, pressure, temperature, and concentration measurements is estimated to be 3%, 0.05%, 0.02 K, and 0.0014%, respectively. The average absolute deviation (AAD) between the measured and calculated reference values for pure water and ammonia is 1.3% and 1.4%, respectively. Correlation models for the thermal conductivity of liquid ammonia + water mixtures were also developed. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000315
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1369–1375
Titre : A comparison of different generalised modelling approaches for a scroll refrigerant compressor Titre original : Comparaison des différentes approches générales à la modélisation du compresseur à spirale frigorifique Type de document : texte imprimé Auteurs : C. K. Lee, Auteur ; H. N. Lam, Auteur Année de publication : 2013 Article en page(s) : pp. 1369–1375 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Vapour-compression cycle; Refrigerant; Polytropic process; Isentropic efficiency; Polytropic efficiency; Polytropic coefficient Résumé : A comparison was made between the errors for the simulated and test performance of a scroll compressor based on three generalised modelling approaches. Four types of refrigerants, namely R22, R134a, R407C and R410A, were analysed, each using a number of compressors which cover the low to medium capacity range. It was found that the use of the constant-polytropic-coefficient approach (CPC) yielded much higher errors in the simulated isentropic efficiencies than those based on the constant-polytropic-efficiency approach (CPE) and the Mallen–Saville approach (MS). The CPE was the best among the three approaches considered, although it was computationally the least efficient. The average errors in the simulated isentropic efficiencies ranged from 8.3 to 10.1% for the four types of refrigerants considered while the corresponding errors in the simulated refrigerant mass flow rates and compressor power inputs varied from 1.1 to 1.8% and 7.7 to 10%. Meanwhile, the simplest CPC should be dismissed on account of the large resultant error and the yielding of incorrect trends in the simulated isentropic efficiencies. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000170 [article] A comparison of different generalised modelling approaches for a scroll refrigerant compressor = Comparaison des différentes approches générales à la modélisation du compresseur à spirale frigorifique [texte imprimé] / C. K. Lee, Auteur ; H. N. Lam, Auteur . - 2013 . - pp. 1369–1375.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1369–1375
Mots-clés : Vapour-compression cycle; Refrigerant; Polytropic process; Isentropic efficiency; Polytropic efficiency; Polytropic coefficient Résumé : A comparison was made between the errors for the simulated and test performance of a scroll compressor based on three generalised modelling approaches. Four types of refrigerants, namely R22, R134a, R407C and R410A, were analysed, each using a number of compressors which cover the low to medium capacity range. It was found that the use of the constant-polytropic-coefficient approach (CPC) yielded much higher errors in the simulated isentropic efficiencies than those based on the constant-polytropic-efficiency approach (CPE) and the Mallen–Saville approach (MS). The CPE was the best among the three approaches considered, although it was computationally the least efficient. The average errors in the simulated isentropic efficiencies ranged from 8.3 to 10.1% for the four types of refrigerants considered while the corresponding errors in the simulated refrigerant mass flow rates and compressor power inputs varied from 1.1 to 1.8% and 7.7 to 10%. Meanwhile, the simplest CPC should be dismissed on account of the large resultant error and the yielding of incorrect trends in the simulated isentropic efficiencies. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000170
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1376–1387
Titre : Experimental study and numerical analysis of thermocompressors with annular regenerators Titre original : Etude expérimentale et analyse numérique des thermocompresseurs munis de régénérateurs annulaires Type de document : texte imprimé Auteurs : Wen-Ye Lin, Auteur ; Xiao-Hua Wu, Auteur ; Jun-Ling Yang, Auteur Année de publication : 2013 Article en page(s) : pp. 1376–1387 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Thermocompressor; Analysis; Thermal energy utilization; Pressure wave; Thermal penetration depth; Wire cutting Résumé : The thermocompressor is capable to utilize thermal energy directly to product pressure wave for pulse tube refrigerator. To research its performance, an experimental system of a thermocompressor with an annular gap regenerator and its corresponding numerical model were established. Then the performance was measured with different heating temperatures, charge pressures and working fluids. The trends of the simulation results are consistent with the experimental ones, whereas the insufficient heat transfer between the gas and annular gap, and clearance volume should be responsible for the quantitative disparity. Therefore, a piston with wire-cut gaps has been designed, fabricated, and tested. With the new piston, the experimental results and the simulation show that the thermocompressor performance has been drastically improved. The analysis also shows that the optimum performance condition is gained when the total thermal penetration depth is approximate to the hydrodynamic radius, which provides a principle for better operation of thermocompressor.
En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000297 [article] Experimental study and numerical analysis of thermocompressors with annular regenerators = Etude expérimentale et analyse numérique des thermocompresseurs munis de régénérateurs annulaires [texte imprimé] / Wen-Ye Lin, Auteur ; Xiao-Hua Wu, Auteur ; Jun-Ling Yang, Auteur . - 2013 . - pp. 1376–1387.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1376–1387
Mots-clés : Thermocompressor; Analysis; Thermal energy utilization; Pressure wave; Thermal penetration depth; Wire cutting Résumé : The thermocompressor is capable to utilize thermal energy directly to product pressure wave for pulse tube refrigerator. To research its performance, an experimental system of a thermocompressor with an annular gap regenerator and its corresponding numerical model were established. Then the performance was measured with different heating temperatures, charge pressures and working fluids. The trends of the simulation results are consistent with the experimental ones, whereas the insufficient heat transfer between the gas and annular gap, and clearance volume should be responsible for the quantitative disparity. Therefore, a piston with wire-cut gaps has been designed, fabricated, and tested. With the new piston, the experimental results and the simulation show that the thermocompressor performance has been drastically improved. The analysis also shows that the optimum performance condition is gained when the total thermal penetration depth is approximate to the hydrodynamic radius, which provides a principle for better operation of thermocompressor.
En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000297
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1388–1398
Titre : Experimental analysis of a reciprocating magnetic refrigeration prototype Titre original : Analyse expérimentale d'un prototype de système frigorifique magnétique alternatif Type de document : texte imprimé Auteurs : J. Romero Gómez, Auteur ; R. Ferreiro Garcia, Auteur ; J. Carbia Carril, Auteur Année de publication : 2013 Article en page(s) : pp. 1388–1398 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Magnetic refrigeration; Design; Experimentation; Gadolinium; Temperature Résumé : In this paper, a reciprocating magnetic refrigeration prototype (MR) with a novel and simple design is presented using permanent magnets for operation at room temperature. The design, installation, operation and preliminary results are reported. The experimental machine is characterised by the implementation of a force compensation system applied on the displacement of the active magnetic regenerator (AMR). Preliminary calculations based on experimental measurements show that approximately 90% of the displacement force is reduced with the proposed design. Using a total of 180 g of Gd as magnetocaloric refrigerant in a magnetic field of 1 T, the device achieved a maximum temperature span under no thermal load of 3.5 K, rendering a cooling power of about 3 W under a span approaching 0 K. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000248 [article] Experimental analysis of a reciprocating magnetic refrigeration prototype = Analyse expérimentale d'un prototype de système frigorifique magnétique alternatif [texte imprimé] / J. Romero Gómez, Auteur ; R. Ferreiro Garcia, Auteur ; J. Carbia Carril, Auteur . - 2013 . - pp. 1388–1398.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1388–1398
Mots-clés : Magnetic refrigeration; Design; Experimentation; Gadolinium; Temperature Résumé : In this paper, a reciprocating magnetic refrigeration prototype (MR) with a novel and simple design is presented using permanent magnets for operation at room temperature. The design, installation, operation and preliminary results are reported. The experimental machine is characterised by the implementation of a force compensation system applied on the displacement of the active magnetic regenerator (AMR). Preliminary calculations based on experimental measurements show that approximately 90% of the displacement force is reduced with the proposed design. Using a total of 180 g of Gd as magnetocaloric refrigerant in a magnetic field of 1 T, the device achieved a maximum temperature span under no thermal load of 3.5 K, rendering a cooling power of about 3 W under a span approaching 0 K. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000248
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1399–1400
Titre : On ejector technology Titre original : Sur la technologie des éjecteurs Type de document : texte imprimé Auteurs : Johann Fischer, Auteur Année de publication : 2013 Article en page(s) : pp. 1399–1400 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Ejectors; Ejector design; Ejector refrigeration systems; History of ejectors En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712002484 [article] On ejector technology = Sur la technologie des éjecteurs [texte imprimé] / Johann Fischer, Auteur . - 2013 . - pp. 1399–1400.
Refrigeration
Langues : Anglais (eng)
in International journal of refrigeration > Vol. 36 N° 4 (Juin 2013) . - pp. 1399–1400
Mots-clés : Ejectors; Ejector design; Ejector refrigeration systems; History of ejectors En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712002484
Exemplaires
| Code-barres | Cote | Support | Localisation | Section | Disponibilité |
|---|---|---|---|---|---|
| aucun exemplaire | |||||
