Documents disponibles écrits par cet auteur

A comparison of the voltage withstand properties of ester and mineral oils / Azcarraga, C. G. in IEEE electrical insulation magazine, Vol. 30 N° 5 (Septembre-Octobre 2014) 

Public ISBD [article]  in IEEE electrical insulation magazine > Vol. 30 N° 5 (Septembre-Octobre 2014) . - pp. 6 - 14 Titre : A comparison of the voltage withstand properties of ester and mineral oils Type de document : texte imprimé Auteurs : Azcarraga, C. G., Auteur ; Alberto Cavallini, Auteur ; Piovan, U., Auteur Année de publication : 2015 Article en page(s) : pp. 6 - 14 Note générale : Génie électrique Langues : Français (fre) Mots-clés : Corona  Minerals  Permittivity  Power  transformer  insulation  Transformer  oil Résumé : EO has proved to be a viable substitute for MO. Its dielectric performance is always comparable with, if not superior to that of MO, at least when new, dried, and highly purified. The smaller permittivity mismatch between pressboard and EO, compared to that between pressboard and MO, leads to a more uniform field distribution at the oil/pressboard interface. We have observed that EO has higher PDIVs than MO for corona and creepage discharges. However, our understanding of the oil/pressboard interface is incomplete. There is a lack of standardization in PDIV measurements, particularly in the case of creepage discharges. Because industry is striving to provide new insulating oils for use at increased transmission voltages, improving electrical testing techniques and the understanding of the oil/pressboard interface is important. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6882595&filter%3DAND% [...] [article] A comparison of the voltage withstand properties of ester and mineral oils [texte imprimé] / Azcarraga, C. G., Auteur ; Alberto Cavallini, Auteur ; Piovan, U., Auteur . - 2015 . - pp. 6 - 14. Génie électrique Langues : Français (fre) in IEEE electrical insulation magazine > Vol. 30 N° 5 (Septembre-Octobre 2014) . - pp. 6 - 14 Mots-clés : Corona  Minerals  Permittivity  Power  transformer  insulation  Transformer  oil Résumé : EO has proved to be a viable substitute for MO. Its dielectric performance is always comparable with, if not superior to that of MO, at least when new, dried, and highly purified. The smaller permittivity mismatch between pressboard and EO, compared to that between pressboard and MO, leads to a more uniform field distribution at the oil/pressboard interface. We have observed that EO has higher PDIVs than MO for corona and creepage discharges. However, our understanding of the oil/pressboard interface is incomplete. There is a lack of standardization in PDIV measurements, particularly in the case of creepage discharges. Because industry is striving to provide new insulating oils for use at increased transmission voltages, improving electrical testing techniques and the understanding of the oil/pressboard interface is important. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=6882595&filter%3DAND% [...]

Heat transfer and pressure drop of natural refrigerants in minichannels (low charge equipment) / Alberto Cavallini 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. 287–300 Titre : Heat transfer and pressure drop of natural refrigerants in minichannels (low charge equipment) Titre original : Transfert de chaleur et chute de pression des frigorigènes naturels à l'intérieur de minicanaux (équipements à faible charge) Type de document : texte imprimé Auteurs : Alberto Cavallini, Auteur ; Davide Del Col, Auteur ; Luisa Rossetto, Auteur Année de publication : 2013 Article en page(s) : pp. 287–300 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Natural  refrigerants;  Heat  transfer;  Pressure  drop;  Minichannels Résumé : The paper presents a comprehensive overview of the most recent research works on heat transfer (and pressure drop) with natural refrigerants in minichannels, aimed at proper design of heat transfer equipment. About boiling heat transfer, experimental HT results are mainly fitted by empirical correlations referring to the common mechanisms used in more conventional geometries (nucleate and convective boiling); evaporation heat transfer through thin liquid film around vapor plugs is at times considered. About shear dominated condensation heat transfer, suggested design tools again mostly refer to the extension of the semi-empirical correlations earlier established for conventional geometries. For CO2, heat transfer at supercritical conditions, such as in a gas cooler, is also treated. Finally the concept of the Penalty Factor is applied to shear condensation in minichannels to establish the heat transfer performance of the different working fluids, the superior effectiveness of minitubes over macrotubes, and the optimization of minichannel condensers. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712003040 [article] Heat transfer and pressure drop of natural refrigerants in minichannels (low charge equipment) = Transfert de chaleur et chute de pression des frigorigènes naturels à l'intérieur de minicanaux (équipements à faible charge) [texte imprimé] / Alberto Cavallini, Auteur ; Davide Del Col, Auteur ; Luisa Rossetto, Auteur . - 2013 . - pp. 287–300. Refrigeration Langues : Anglais (eng) in International journal of refrigeration > Vol. 36 N° 2 (N° spécial) (Mars 2013) . - pp. 287–300 Mots-clés : Natural  refrigerants;  Heat  transfer;  Pressure  drop;  Minichannels Résumé : The paper presents a comprehensive overview of the most recent research works on heat transfer (and pressure drop) with natural refrigerants in minichannels, aimed at proper design of heat transfer equipment. About boiling heat transfer, experimental HT results are mainly fitted by empirical correlations referring to the common mechanisms used in more conventional geometries (nucleate and convective boiling); evaporation heat transfer through thin liquid film around vapor plugs is at times considered. About shear dominated condensation heat transfer, suggested design tools again mostly refer to the extension of the semi-empirical correlations earlier established for conventional geometries. For CO2, heat transfer at supercritical conditions, such as in a gas cooler, is also treated. Finally the concept of the Penalty Factor is applied to shear condensation in minichannels to establish the heat transfer performance of the different working fluids, the superior effectiveness of minitubes over macrotubes, and the optimization of minichannel condensers. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712003040

Performance of a large capacity propane heat pump with low charge heat exchangers / Alberto Cavallini 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. 242-250 Titre : Performance of a large capacity propane heat pump with low charge heat exchangers Titre original : Performance d’une pompe à chaleur au propane d’une grande puissance avec des échangeurs de chaleur à faible charge Type de document : texte imprimé Auteurs : Alberto Cavallini, Auteur ; Enrico Da Riva, Auteur ; Davide Del Col, Auteur Année de publication : 2011 Article en page(s) : pp. 242-250 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Heat  pump  Water  source  Compression  system  Propane  Experiment  Performance  Micro-channel  Reduction  Refrigerant  charge Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : The experimental performance of a 100 kW heat pump using propane is presented. The charge minimization is a priority in the design of such a device and thus shell-and-tube heat exchangers using minichannels and providing low charge have been installed in the unit, along with conventional brazed plate heat exchangers, in order to compare different working configurations, both in terms of energy efficiency and refrigerant charge. The performance when using the minichannel condenser is here compared to the one obtained when using a brazed plate condenser and the influence of a minichannel internal heat exchanger on the performance of the equipment is measured and discussed. It is shown that a 100 kW heat pump without a liquid receiver could be run with around 3 kg of propane using a plate condenser and a plate evaporator. Using the minichannel condenser, around 0.8 kg reduction can be obtained with a negligible performance loss. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700709002448 [article] Performance of a large capacity propane heat pump with low charge heat exchangers = Performance d’une pompe à chaleur au propane d’une grande puissance avec des échangeurs de chaleur à faible charge [texte imprimé] / Alberto Cavallini, Auteur ; Enrico Da Riva, Auteur ; Davide Del Col, Auteur . - 2011 . - pp. 242-250. Génie Mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 33 N° 2 (Mars 2010) . - pp. 242-250 Mots-clés : Heat  pump  Water  source  Compression  system  Propane  Experiment  Performance  Micro-channel  Reduction  Refrigerant  charge Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : The experimental performance of a 100 kW heat pump using propane is presented. The charge minimization is a priority in the design of such a device and thus shell-and-tube heat exchangers using minichannels and providing low charge have been installed in the unit, along with conventional brazed plate heat exchangers, in order to compare different working configurations, both in terms of energy efficiency and refrigerant charge. The performance when using the minichannel condenser is here compared to the one obtained when using a brazed plate condenser and the influence of a minichannel internal heat exchanger on the performance of the equipment is measured and discussed. It is shown that a 100 kW heat pump without a liquid receiver could be run with around 3 kg of propane using a plate condenser and a plate evaporator. Using the minichannel condenser, around 0.8 kg reduction can be obtained with a negligible performance loss. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700709002448

Thermodynamic properties of eight fluorinated olefins / J. Steven Brown 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. 235-241 Titre : Thermodynamic properties of eight fluorinated olefins Titre original : Propriétés thermodynamiques de huit oléfines fluorées Type de document : texte imprimé Auteurs : J. Steven Brown, Auteur ; Claudio Zilio, Auteur ; Alberto Cavallini, Auteur Année de publication : 2011 Article en page(s) : pp. 235-241 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Refrigerant  R-1225ye(E)  R1225ye(Z)  R1225zc  R1234ye(E)  R1234yf  R1234ze(E)  R1234ze(Z)  R1243zf Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : Group contribution methods are used to predict the critical temperatures, critical pressures, critical densities, acentric factors, and ideal gas specific heats at constant pressure for eight fluorinated olefins, namely: R-1225ye(E), R-1225ye(Z), R-1225zc, R-1234ye(E), R-1234yf, R-1234ze(E), R-1234ze(Z), and R-1243zf. For the same eight refrigerants, the Peng–Robinson equation of state is used to predict thermodynamic properties, which are presented in pressure-enthalpy and temperature-entropy state diagrams. To provide the reader with some sense of the predictive capability of the methodology, property predictions for R-134a are compared to known data. Property predictions for R-1234yf are compared, where possible, to the open literature. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700709000930 [article] Thermodynamic properties of eight fluorinated olefins = Propriétés thermodynamiques de huit oléfines fluorées [texte imprimé] / J. Steven Brown, Auteur ; Claudio Zilio, Auteur ; Alberto Cavallini, Auteur . - 2011 . - pp. 235-241. Génie Mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 33 N° 2 (Mars 2010) . - pp. 235-241 Mots-clés : Refrigerant  R-1225ye(E)  R1225ye(Z)  R1225zc  R1234ye(E)  R1234yf  R1234ze(E)  R1234ze(Z)  R1243zf Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : Group contribution methods are used to predict the critical temperatures, critical pressures, critical densities, acentric factors, and ideal gas specific heats at constant pressure for eight fluorinated olefins, namely: R-1225ye(E), R-1225ye(Z), R-1225zc, R-1234ye(E), R-1234yf, R-1234ze(E), R-1234ze(Z), and R-1243zf. For the same eight refrigerants, the Peng–Robinson equation of state is used to predict thermodynamic properties, which are presented in pressure-enthalpy and temperature-entropy state diagrams. To provide the reader with some sense of the predictive capability of the methodology, property predictions for R-134a are compared to known data. Property predictions for R-1234yf are compared, where possible, to the open literature. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700709000930