Documents disponibles écrits par cet auteur

Air-side heat transfer characteristics of spiral-type circular fin-tube heat exchangers / Mooyeon Lee in International journal of refrigeration, Vol. 33 N° 2 (Mars 2010) 

Public ISBD [article]  in International journal of refrigeration > Vol. 33 N° 2 (Mars 2010) . - pp. 313-320 Titre : Air-side heat transfer characteristics of spiral-type circular fin-tube heat exchangers Titre original : Caractéristiques de transfert de chaleur côté air des échangeurs de chaleur circulaires hélicoïdaux à tubes ailetés Type de document : texte imprimé Auteurs : Mooyeon Lee, Auteur ; Taehyung Kang, Auteur ; Yongchan Kim, Auteur Année de publication : 2011 Article en page(s) : pp. 313-320 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Chiller  Heat  exchanger  Finned  tube  Spiral  Geometry  Experiment  Heat  transfer Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : The objective of this study is to investigate the air-side heat transfer characteristics of spiral-type circular fin-tube heat exchangers used as evaporators in household refrigerators. The j-factors of the tested heat exchangers under non-frosting conditions were measured by varying the fin pitch, number of tube rows, and fin alignment. The j-factors of the spiral-type circular fin-tube heat exchangers were analyzed as a function of heat exchanger geometries and then compared with those of the flat plate fin-tube heat exchangers with discrete fins. Two empirical correlations of the j-factors were developed separately for the inline and the staggered fin alignment as a function of the Reynolds number, number of tube rows, and dimensionless fin pitch normalized by the hydraulic diameter. The mean deviation of the predictions using the present correlations from the measured data was 4.78% for the inline fin alignment and 6.02% for the staggered fin alignment. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700709002308 [article] Air-side heat transfer characteristics of spiral-type circular fin-tube heat exchangers = Caractéristiques de transfert de chaleur côté air des échangeurs de chaleur circulaires hélicoïdaux à tubes ailetés [texte imprimé] / Mooyeon Lee, Auteur ; Taehyung Kang, Auteur ; Yongchan Kim, Auteur . - 2011 . - pp. 313-320. Génie Mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 33 N° 2 (Mars 2010) . - pp. 313-320 Mots-clés : Chiller  Heat  exchanger  Finned  tube  Spiral  Geometry  Experiment  Heat  transfer Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : The objective of this study is to investigate the air-side heat transfer characteristics of spiral-type circular fin-tube heat exchangers used as evaporators in household refrigerators. The j-factors of the tested heat exchangers under non-frosting conditions were measured by varying the fin pitch, number of tube rows, and fin alignment. The j-factors of the spiral-type circular fin-tube heat exchangers were analyzed as a function of heat exchanger geometries and then compared with those of the flat plate fin-tube heat exchangers with discrete fins. Two empirical correlations of the j-factors were developed separately for the inline and the staggered fin alignment as a function of the Reynolds number, number of tube rows, and dimensionless fin pitch normalized by the hydraulic diameter. The mean deviation of the predictions using the present correlations from the measured data was 4.78% for the inline fin alignment and 6.02% for the staggered fin alignment. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700709002308

Development of an optimization strategy for insulation thickness of a domestic refrigerator-freezer / Won Jae Yoon in International journal of refrigeration, Vol. 36 N° 3 (Mai 2013) 

Public ISBD [article]  in International journal of refrigeration > Vol. 36 N° 3 (Mai 2013) . - pp. 1162–1172 Titre : Development of an optimization strategy for insulation thickness of a domestic refrigerator-freezer Titre original : Développement d'une stratégie d'optimisation de l'épaisseur de l'isolation à l'intérieur d'un réfrigérateur / congélateur domestique Type de document : texte imprimé Auteurs : Won Jae Yoon, Auteur ; Kookjeong Seo, Auteur ; Yongchan Kim, Auteur Année de publication : 2013 Article en page(s) : pp. 1162–1172 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Insulation;  Efficiency;  Performance;  Optimization;  Household  refrigerator Résumé : The optimization of insulation thickness is very important to increase the performance of domestic refrigerator-freezers (RFs) because of its strong dependency on the heat load through polyurethane-insulated compartments. However, it is very difficult to find the optimum insulation thickness to allow minimum energy consumption at the arbitrarily given COP and internal volume of each compartment. In this study, the optimization process for the insulation thickness was proposed to improve the energy efficiency of a total RF system. This process included the quantitative relationships between the COP and the insulation thickness of each compartment. In addition, the effects of the proposed optimization strategy on the performance of RF were investigated in the bypass two-circuit cycle and the dual-loop cycle. As a result, the energy consumptions of the bypass two-circuit cycle and the dual-loop cycle were reduced by 5.7% and 6.1%, respectively, by applying the proposed optimization strategy. En ligne : http://www.sciencedirect.com/science/article/pii/S014070071200312X [article] Development of an optimization strategy for insulation thickness of a domestic refrigerator-freezer = Développement d'une stratégie d'optimisation de l'épaisseur de l'isolation à l'intérieur d'un réfrigérateur / congélateur domestique [texte imprimé] / Won Jae Yoon, Auteur ; Kookjeong Seo, Auteur ; Yongchan Kim, Auteur . - 2013 . - pp. 1162–1172. Refrigeration Langues : Anglais (eng) in International journal of refrigeration > Vol. 36 N° 3 (Mai 2013) . - pp. 1162–1172 Mots-clés : Insulation;  Efficiency;  Performance;  Optimization;  Household  refrigerator Résumé : The optimization of insulation thickness is very important to increase the performance of domestic refrigerator-freezers (RFs) because of its strong dependency on the heat load through polyurethane-insulated compartments. However, it is very difficult to find the optimum insulation thickness to allow minimum energy consumption at the arbitrarily given COP and internal volume of each compartment. In this study, the optimization process for the insulation thickness was proposed to improve the energy efficiency of a total RF system. This process included the quantitative relationships between the COP and the insulation thickness of each compartment. In addition, the effects of the proposed optimization strategy on the performance of RF were investigated in the bypass two-circuit cycle and the dual-loop cycle. As a result, the energy consumptions of the bypass two-circuit cycle and the dual-loop cycle were reduced by 5.7% and 6.1%, respectively, by applying the proposed optimization strategy. En ligne : http://www.sciencedirect.com/science/article/pii/S014070071200312X

Effects of flash tank vapor injection on the heating performance of an inverter-driven heat pump for cold regions / Jaehyeok Heo in International journal of refrigeration, Vol. 33 N° 4 (Juin 2010) 

Public ISBD [article]  in International journal of refrigeration > Vol. 33 N° 4 (Juin 2010) . - pp. 848-855 Titre : Effects of flash tank vapor injection on the heating performance of an inverter-driven heat pump for cold regions Titre original : Effets de ĺinjection de la vapeur du réservoir intermédiaire sur la performance en application chauffage d'une pompe à chaleur entraînée par convertisseur dans les climats froids Type de document : texte imprimé Auteurs : Jaehyeok Heo, Auteur ; Min Woo Jeong, Auteur ; Yongchan Kim, Auteur Année de publication : 2010 Article en page(s) : pp. 848-855 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Heat  pump  Two-stage  system  Variable  speed  Compressor  Experiment  Injection  Performance  COP Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : A heat pump has received much attention as substitute for the conventional boiler or heating coil because of its high efficiency. For the wide application of the heat pump, the most important design factor is the performance degradation upon its installation in tropical and cold regions. In this study, the effects of flash tank vapor injection on the heating performance of a two-stage heat pump with an inverter-driven twin rotary compressor were measured and analyzed for compressor frequency ranging from 50 to 100 Hz at ambient temperatures of −15, −5, and 5 °C. The COP and heating capacity of the injection cycle were enhanced by 10% and 25%, respectively, at the ambient temperature of −15 °C. The total mass flow rate of the injection cycle was 30–38% higher than that of the non-injection cycle. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710000022 [article] Effects of flash tank vapor injection on the heating performance of an inverter-driven heat pump for cold regions = Effets de ĺinjection de la vapeur du réservoir intermédiaire sur la performance en application chauffage d'une pompe à chaleur entraînée par convertisseur dans les climats froids [texte imprimé] / Jaehyeok Heo, Auteur ; Min Woo Jeong, Auteur ; Yongchan Kim, Auteur . - 2010 . - pp. 848-855. Génie Mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 33 N° 4 (Juin 2010) . - pp. 848-855 Mots-clés : Heat  pump  Two-stage  system  Variable  speed  Compressor  Experiment  Injection  Performance  COP Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : A heat pump has received much attention as substitute for the conventional boiler or heating coil because of its high efficiency. For the wide application of the heat pump, the most important design factor is the performance degradation upon its installation in tropical and cold regions. In this study, the effects of flash tank vapor injection on the heating performance of a two-stage heat pump with an inverter-driven twin rotary compressor were measured and analyzed for compressor frequency ranging from 50 to 100 Hz at ambient temperatures of −15, −5, and 5 °C. The COP and heating capacity of the injection cycle were enhanced by 10% and 25%, respectively, at the ambient temperature of −15 °C. The total mass flow rate of the injection cycle was 30–38% higher than that of the non-injection cycle. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710000022

Optimum cycle control of a two-stage injection heat pump with a double expansion sub-cooler / Jaehyeok Heo in International journal of refrigeration, Vol. 35 N° 1 (Janvier 2012) 

Public ISBD [article]  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

Simulations on the performance of a vapor-injection heat pump for different cylinder volume ratios of a twin rotary compressor / Jaehyeok Heo in International journal of refrigeration, Vol. 36 N° 3 (Mai 2013) 

Public ISBD [article]  in International journal of refrigeration > Vol. 36 N° 3 (Mai 2013) . - pp. 730–744 Titre : Simulations on the performance of a vapor-injection heat pump for different cylinder volume ratios of a twin rotary compressor Titre original : Simulations de la performance d'une pompe à chaleur à injection de vapeur pour plusieurs volumes de cylindres d'un compresseur rotatif à deux cylindres Type de document : texte imprimé Auteurs : Jaehyeok Heo, Auteur ; Rin Yun, Auteur ; Yongchan Kim, Auteur Année de publication : 2013 Article en page(s) : pp. 730–744 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Heat  pump;  Injection;  Rotary  compressor;  Simulation;  Cylinder  volume Résumé : In residential air-source heat pump systems, the refrigerant injection technique has rapidly developed in recent years due to its outstanding performance at low ambient temperatures. A numerical simulation model of a flash tank vapor-injection heat pump with a twin rotary compressor is newly presented in this paper. The performance of the twin rotary compressor with refrigerant injection was simulated using a loss and efficiency model. The model was validated by comparing the predictions with measured data. In addition, the model was used to analyze the performance characteristics of the vapor-injection heat pump according to the cylinder volume ratio of the twin rotary compressor. Based on the simulation results, optimum cylinder volume ratios were suggested for various design conditions, including for the fixed first cylinder volume, the fixed total cylinder volume, and the fixed heating capacity. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712002757 [article] Simulations on the performance of a vapor-injection heat pump for different cylinder volume ratios of a twin rotary compressor = Simulations de la performance d'une pompe à chaleur à injection de vapeur pour plusieurs volumes de cylindres d'un compresseur rotatif à deux cylindres [texte imprimé] / Jaehyeok Heo, Auteur ; Rin Yun, Auteur ; Yongchan Kim, Auteur . - 2013 . - pp. 730–744. Refrigeration Langues : Anglais (eng) in International journal of refrigeration > Vol. 36 N° 3 (Mai 2013) . - pp. 730–744 Mots-clés : Heat  pump;  Injection;  Rotary  compressor;  Simulation;  Cylinder  volume Résumé : In residential air-source heat pump systems, the refrigerant injection technique has rapidly developed in recent years due to its outstanding performance at low ambient temperatures. A numerical simulation model of a flash tank vapor-injection heat pump with a twin rotary compressor is newly presented in this paper. The performance of the twin rotary compressor with refrigerant injection was simulated using a loss and efficiency model. The model was validated by comparing the predictions with measured data. In addition, the model was used to analyze the performance characteristics of the vapor-injection heat pump according to the cylinder volume ratio of the twin rotary compressor. Based on the simulation results, optimum cylinder volume ratios were suggested for various design conditions, including for the fixed first cylinder volume, the fixed total cylinder volume, and the fixed heating capacity. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712002757