Documents disponibles écrits par cet auteur

Condensation of the low GWP refrigerant HFC1234yf inside a brazed plate heat exchanger / Giovanni A. Longo in International journal of refrigeration, Vol. 36 N° 2 (N° spécial) (Mars 2013) 

Public ISBD [article]  in International journal of refrigeration > Vol. 36 N° 2 (N° spécial) (Mars 2013) . - pp. 612–621 Titre : Condensation of the low GWP refrigerant HFC1234yf inside a brazed plate heat exchanger Titre original : Condensation du frigorigène à faible GWP HFC1234yf à l'intérieur d'un échangeur de chaleur à plaques brasées Type de document : texte imprimé Auteurs : Giovanni A. Longo, Auteur ; Claudio Zilio, Auteur Année de publication : 2013 Article en page(s) : pp. 612–621 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Condensation;  Heat  transfer  coefficient;  Pressure  drop;  Super-heat;  GWP Résumé : This paper presents the heat transfer coefficients and the pressure drop measured during condensation of the new low Global Warming Potential (GWP) refrigerant HFO1234yf inside a brazed plate heat exchanger: the effects of saturation temperature, refrigerant mass flux and vapour super-heating are investigated. The heat transfer coefficients show weak sensitivity to saturation temperature and great sensitivity to refrigerant mass flux. At low refrigerant mass flux (<20 kg m−2 s−1) the heat transfer coefficients are not dependent on mass flux and condensation is controlled by gravity. For higher refrigerant mass flux (>20 kg m−2 s−1) the heat transfer coefficients depend on mass flux and forced convection condensation occurs. The condensation heat transfer coefficients of super-heated vapour are from 8 to 11% higher than those of saturated vapour. HFO1234yf exhibits heat transfer coefficients lower (10–12%) and frictional pressure drop lower (10–20%) than those of HFC134a under the same operating conditions. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000145 [article] Condensation of the low GWP refrigerant HFC1234yf inside a brazed plate heat exchanger = Condensation du frigorigène à faible GWP HFC1234yf à l'intérieur d'un échangeur de chaleur à plaques brasées [texte imprimé] / Giovanni A. Longo, Auteur ; Claudio Zilio, Auteur . - 2013 . - pp. 612–621. Refrigeration Langues : Anglais (eng) in International journal of refrigeration > Vol. 36 N° 2 (N° spécial) (Mars 2013) . - pp. 612–621 Mots-clés : Condensation;  Heat  transfer  coefficient;  Pressure  drop;  Super-heat;  GWP Résumé : This paper presents the heat transfer coefficients and the pressure drop measured during condensation of the new low Global Warming Potential (GWP) refrigerant HFO1234yf inside a brazed plate heat exchanger: the effects of saturation temperature, refrigerant mass flux and vapour super-heating are investigated. The heat transfer coefficients show weak sensitivity to saturation temperature and great sensitivity to refrigerant mass flux. At low refrigerant mass flux (<20 kg m−2 s−1) the heat transfer coefficients are not dependent on mass flux and condensation is controlled by gravity. For higher refrigerant mass flux (>20 kg m−2 s−1) the heat transfer coefficients depend on mass flux and forced convection condensation occurs. The condensation heat transfer coefficients of super-heated vapour are from 8 to 11% higher than those of saturated vapour. HFO1234yf exhibits heat transfer coefficients lower (10–12%) and frictional pressure drop lower (10–20%) than those of HFC134a under the same operating conditions. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713000145

Condensation of the low GWP refrigerant HFO1234ze(E) inside a Brazed Plate Heat Exchanger / Giovanni A. Longo in International journal of refrigeration, Vol. 38 (Février 2014) 

Public ISBD [article]  in International journal of refrigeration > Vol. 38 (Février 2014) . - pp. 250–259 Titre : Condensation of the low GWP refrigerant HFO1234ze(E) inside a Brazed Plate Heat Exchanger Titre original : Condensation du frigorigène à faible GWP HFO1234ze dans un échangeur de chaleur à plaques brasées Type de document : texte imprimé Auteurs : Giovanni A. Longo, Auteur ; Claudio Zilio, Auteur ; Giulia Righetti, Auteur Année de publication : 2014 Article en page(s) : pp. 250–259 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Condensation;  Heat  transfer  coefficient;  Pressure  drop;  Super-heat;  GWP;  BPHE Résumé : This paper presents heat transfer coefficients and pressure drops measured during condensation of the low GWP refrigerant HFO1234ze(E) inside a BPHE. The condensation temperature ranges between 24.8 and 40.2 °C, the refrigerant mass flux from 10.7 to 39.9 kg m−2 s−1 and the heat flux from 5.3 to 26 kW m−2. The heat transfer coefficients show weak sensitivity to saturation temperature and great sensitivity to refrigerant mass flux and vapour super-heating. At low refrigerant mass fluxes (<20 kg m−2 s−1) the heat transfer coefficients are independent of mass flux and condensation is gravity-dominated. For higher refrigerant mass fluxes (>20 kg m−2 s−1) the heat transfer coefficients depend on mass flux and forced convection condensation occurs. In the forced convection condensation region the heat transfer coefficients show a 32%–35% enhancement for a doubling of the refrigerant mass flux. The condensation heat transfer coefficients of super-heated vapour are from 8% to 11% higher than those of saturated vapour. HFO1234ze(E) exhibits lower (4%–6%) heat transfer coefficients and higher (10%) frictional pressure drops than those of HFC134a. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713002211 [article] Condensation of the low GWP refrigerant HFO1234ze(E) inside a Brazed Plate Heat Exchanger = Condensation du frigorigène à faible GWP HFO1234ze dans un échangeur de chaleur à plaques brasées [texte imprimé] / Giovanni A. Longo, Auteur ; Claudio Zilio, Auteur ; Giulia Righetti, Auteur . - 2014 . - pp. 250–259. Refrigeration Langues : Anglais (eng) in International journal of refrigeration > Vol. 38 (Février 2014) . - pp. 250–259 Mots-clés : Condensation;  Heat  transfer  coefficient;  Pressure  drop;  Super-heat;  GWP;  BPHE Résumé : This paper presents heat transfer coefficients and pressure drops measured during condensation of the low GWP refrigerant HFO1234ze(E) inside a BPHE. The condensation temperature ranges between 24.8 and 40.2 °C, the refrigerant mass flux from 10.7 to 39.9 kg m−2 s−1 and the heat flux from 5.3 to 26 kW m−2. The heat transfer coefficients show weak sensitivity to saturation temperature and great sensitivity to refrigerant mass flux and vapour super-heating. At low refrigerant mass fluxes (<20 kg m−2 s−1) the heat transfer coefficients are independent of mass flux and condensation is gravity-dominated. For higher refrigerant mass fluxes (>20 kg m−2 s−1) the heat transfer coefficients depend on mass flux and forced convection condensation occurs. In the forced convection condensation region the heat transfer coefficients show a 32%–35% enhancement for a doubling of the refrigerant mass flux. The condensation heat transfer coefficients of super-heated vapour are from 8% to 11% higher than those of saturated vapour. HFO1234ze(E) exhibits lower (4%–6%) heat transfer coefficients and higher (10%) frictional pressure drops than those of HFC134a. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713002211

Experimental analysis of a new method for overfeeding multiple evaporators in refrigeration systems / Silvia Minetto in International journal of refrigeration, Vol. 38 (Février 2014) 

Public ISBD [article]  in International journal of refrigeration > Vol. 38 (Février 2014) . - pp. 1–9 Titre : Experimental analysis of a new method for overfeeding multiple evaporators in refrigeration systems Titre original : Analyse expérimentale d'une nouvelle méthode pour la suralimentation d'évaporateurs multiples dans des systèmes frigorifiques Type de document : texte imprimé Auteurs : Silvia Minetto, Auteur ; Riccardo Brignoli, Auteur ; Claudio Zilio, Auteur Année de publication : 2014 Article en page(s) : pp. 1–9 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : CO2;  Flooded  evaporator;  Thermostatic  valve;  Ejector;  Transcritical  cycle Résumé : An innovative method for feeding flooded evaporators, arranged in parallel in R744 plants, is presented. In order to promote evaporators overfeeding, an ejector circulates liquid from the low pressure receiver back to the intermediate pressure receiver. Since there is not a need for superheat at the evaporator exit, each evaporator expansion valve can be controlled by a signal representative, either of the evaporator load, or the evaporator performance, such as the air temperature at its inlet or outlet. When compared to dry-expansion evaporator systems, the proposed solution offers energy saving and smooth operating conditions, typical of flooded evaporators, while still maintaining a simple plant lay-out. The concept was experimentally validated: the evaporators were maintained in flooded conditions, while the ejector was able to promote liquid recirculation. Direct comparison with dry-expansion operations was performed. The suggested method is mainly intended for commercial refrigeration plants, where many evaporators are arranged in parallel. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713002788 [article] Experimental analysis of a new method for overfeeding multiple evaporators in refrigeration systems = Analyse expérimentale d'une nouvelle méthode pour la suralimentation d'évaporateurs multiples dans des systèmes frigorifiques [texte imprimé] / Silvia Minetto, Auteur ; Riccardo Brignoli, Auteur ; Claudio Zilio, Auteur . - 2014 . - pp. 1–9. Refrigeration Langues : Anglais (eng) in International journal of refrigeration > Vol. 38 (Février 2014) . - pp. 1–9 Mots-clés : CO2;  Flooded  evaporator;  Thermostatic  valve;  Ejector;  Transcritical  cycle Résumé : An innovative method for feeding flooded evaporators, arranged in parallel in R744 plants, is presented. In order to promote evaporators overfeeding, an ejector circulates liquid from the low pressure receiver back to the intermediate pressure receiver. Since there is not a need for superheat at the evaporator exit, each evaporator expansion valve can be controlled by a signal representative, either of the evaporator load, or the evaporator performance, such as the air temperature at its inlet or outlet. When compared to dry-expansion evaporator systems, the proposed solution offers energy saving and smooth operating conditions, typical of flooded evaporators, while still maintaining a simple plant lay-out. The concept was experimentally validated: the evaporators were maintained in flooded conditions, while the ejector was able to promote liquid recirculation. Direct comparison with dry-expansion operations was performed. The suggested method is mainly intended for commercial refrigeration plants, where many evaporators are arranged in parallel. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700713002788

Heat transfer performance of aluminum foams / Simone Mancin in Journal of heat transfer, Vol. 133 N° 6 (Juin 2011) 

Public ISBD [article]  in Journal of heat transfer > Vol. 133 N° 6 (Juin 2011) . - pp. [060904/1-9] Titre : Heat transfer performance of aluminum foams Type de document : texte imprimé Auteurs : Simone Mancin, Auteur ; Claudio Zilio, Auteur ; Luisa Rossetto, Auteur Année de publication : 2011 Article en page(s) : pp. [060904/1-9] Note générale : Physique Langues : Anglais (eng) Mots-clés : Convection  Experimental  Heat  transfer  Pressure  drop  Porous  media Index. décimale : 536 Chaleur. Thermodynamique Résumé : Because of their interesting heat transfer and mechanical properties, metal foams have been proposed for several different applications, thermal and structural. This paper aims at pointing out the effective thermal fluid dynamic behavior of these new enhanced surfaces, which present high heat transfer area per unit of volume at the expense of high pressure drop. The paper presents the experimental heat transfer and pressure drop measurements relative to air flowing in forced convection through four different aluminum foams, when electrically heated. The tested aluminum foams present 5, 10, 20 and 40 PPI (pores per inch), porosity around 0.92–0.93, and 0.02 m of foam core height. The experimental heat transfer coefficients and pressure drops have been obtained by varying the air mass flow rate and the electrical power, which has been set at 25.0 kW m−2, 32.5 kW m−2, and 40.0 kW m−2. The results have been compared against those measured for 40 mm high samples, in order to study the effects of the foam core height on the heat transfer. Moreover, predictions from two recent models are compared with heat transfer coefficient and pressure drop experimental data. The predictions are in good agreement with experimental data. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...] [article] Heat transfer performance of aluminum foams [texte imprimé] / Simone Mancin, Auteur ; Claudio Zilio, Auteur ; Luisa Rossetto, Auteur . - 2011 . - pp. [060904/1-9]. Physique Langues : Anglais (eng) in Journal of heat transfer > Vol. 133 N° 6 (Juin 2011) . - pp. [060904/1-9] Mots-clés : Convection  Experimental  Heat  transfer  Pressure  drop  Porous  media Index. décimale : 536 Chaleur. Thermodynamique Résumé : Because of their interesting heat transfer and mechanical properties, metal foams have been proposed for several different applications, thermal and structural. This paper aims at pointing out the effective thermal fluid dynamic behavior of these new enhanced surfaces, which present high heat transfer area per unit of volume at the expense of high pressure drop. The paper presents the experimental heat transfer and pressure drop measurements relative to air flowing in forced convection through four different aluminum foams, when electrically heated. The tested aluminum foams present 5, 10, 20 and 40 PPI (pores per inch), porosity around 0.92–0.93, and 0.02 m of foam core height. The experimental heat transfer coefficients and pressure drops have been obtained by varying the air mass flow rate and the electrical power, which has been set at 25.0 kW m−2, 32.5 kW m−2, and 40.0 kW m−2. The results have been compared against those measured for 40 mm high samples, in order to study the effects of the foam core height on the heat transfer. Moreover, predictions from two recent models are compared with heat transfer coefficient and pressure drop experimental data. The predictions are in good agreement with experimental data. DEWEY : 536 ISSN : 0022-1481 En ligne : http://asmedl.aip.org/vsearch/servlet/VerityServlet?KEY=JHTRAO&ONLINE=YES&smode= [...]

Mini Vapor Cycle System for high density electronic cooling applications / Simone Mancin in International journal of refrigeration, Vol. 36 N° 4 (Juin 2013) 

Public ISBD [article]  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

Thermodynamic properties of eight fluorinated olefins / J. Steven Brown in International journal of refrigeration, Vol. 33 N° 2 (Mars 2010) 

Permalink