Documents disponibles écrits par cet auteur

Flow boiling of R1234yf in a 1 mm diameter channel / Davide Del Col 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. 353–362 Titre : Flow boiling of R1234yf in a 1 mm diameter channel Titre original : Ébullition en écoulement du R1234yf dans un canal d'un diamètre de 1 mm Type de document : texte imprimé Auteurs : Davide Del Col, Auteur ; Stefano Bortolin, Auteur ; Daniele Torresin, Auteur Année de publication : 2013 Article en page(s) : pp. 353–362 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Evaporator;  Microchannel;  R1234yf;  Flow  boiling Résumé : Since many HFC refrigerants have relatively large values of GWP, recent development efforts have been initiated to investigate halogenated olefins as possible refrigerants, with fluorinated propene isomers, in particular, having emerged as possible solutions. Specifically, R1234yf has emerged as an R134a replacement for automotive applications. In this paper, the local heat transfer coefficient measured during flow boiling of R1234yf in a 1 mm diameter circular microchannel is reported and compared to R134a. During tests, the heat is provided to the boiling fluid by using a secondary fluid. Therefore the heat flux is not imposed but instead it is the result of the inlet temperatures of the two fluids and the thermal resistances on the two sides, as it occurs in actual heat exchangers for automotive and air-conditioning applications. Flow boiling tests are carried out at 31 °C saturation temperature and mass fluxes ranging between 200 kg m−2 s−1 and 600 kg m−2 s−1. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712002861 [article] Flow boiling of R1234yf in a 1 mm diameter channel = Ébullition en écoulement du R1234yf dans un canal d'un diamètre de 1 mm [texte imprimé] / Davide Del Col, Auteur ; Stefano Bortolin, Auteur ; Daniele Torresin, Auteur . - 2013 . - pp. 353–362. Refrigeration Langues : Anglais (eng) in International journal of refrigeration > Vol. 36 N° 2 (N° spécial) (Mars 2013) . - pp. 353–362 Mots-clés : Evaporator;  Microchannel;  R1234yf;  Flow  boiling Résumé : Since many HFC refrigerants have relatively large values of GWP, recent development efforts have been initiated to investigate halogenated olefins as possible refrigerants, with fluorinated propene isomers, in particular, having emerged as possible solutions. Specifically, R1234yf has emerged as an R134a replacement for automotive applications. In this paper, the local heat transfer coefficient measured during flow boiling of R1234yf in a 1 mm diameter circular microchannel is reported and compared to R134a. During tests, the heat is provided to the boiling fluid by using a secondary fluid. Therefore the heat flux is not imposed but instead it is the result of the inlet temperatures of the two fluids and the thermal resistances on the two sides, as it occurs in actual heat exchangers for automotive and air-conditioning applications. Flow boiling tests are carried out at 31 °C saturation temperature and mass fluxes ranging between 200 kg m−2 s−1 and 600 kg m−2 s−1. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712002861

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

Performance of a semi-hermetic reciprocating compressor with propane and mineral oil / Enrico Da Riva in International journal of refrigeration, Vol. 34 N° 3 (Mai 2011) 

Public ISBD [article]  in International journal of refrigeration > Vol. 34 N° 3 (Mai 2011) . - pp. 752-763 Titre : Performance of a semi-hermetic reciprocating compressor with propane and mineral oil Titre original : Performance d'un compresseur à piston semi-hermétique fonctionnant au propane et à l'huile minérale Type de document : texte imprimé Auteurs : Enrico Da Riva, Auteur ; Davide Del Col, Auteur Année de publication : 2011 Article en page(s) : pp. 752-763 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Propane  Compressor  Semi-hermetic  Reciprocating  Lubricant  Mineral  oil Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : The experimental performance of a semi-hermetic reciprocating compressor working with propane as the refrigerant is reported in the present paper. Tests have been performed both with and without an internal heat exchanger between the vapour suction line and the liquid line, at different settings of the expansion valve. The suction vapour superheating is shown to improve volumetric efficiency and, therefore, global compression efficiency. Experimental results are discussed and explained by means of the high solubility of propane in the mineral oil used as the lubricant, which can cause an excessive reduction of the refrigerant–oil mixture viscosity at low suction superheating. Besides, the possibility of condensation on a cold spot inside the cylinder has also been considered. A modified version of the empirical model by Pierre (1982) for the prediction of volumetric and global compression efficiencies is proposed for propane DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002884 [article] Performance of a semi-hermetic reciprocating compressor with propane and mineral oil = Performance d'un compresseur à piston semi-hermétique fonctionnant au propane et à l'huile minérale [texte imprimé] / Enrico Da Riva, Auteur ; Davide Del Col, Auteur . - 2011 . - pp. 752-763. Génie Mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 34 N° 3 (Mai 2011) . - pp. 752-763 Mots-clés : Propane  Compressor  Semi-hermetic  Reciprocating  Lubricant  Mineral  oil Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : The experimental performance of a semi-hermetic reciprocating compressor working with propane as the refrigerant is reported in the present paper. Tests have been performed both with and without an internal heat exchanger between the vapour suction line and the liquid line, at different settings of the expansion valve. The suction vapour superheating is shown to improve volumetric efficiency and, therefore, global compression efficiency. Experimental results are discussed and explained by means of the high solubility of propane in the mineral oil used as the lubricant, which can cause an excessive reduction of the refrigerant–oil mixture viscosity at low suction superheating. Besides, the possibility of condensation on a cold spot inside the cylinder has also been considered. A modified version of the empirical model by Pierre (1982) for the prediction of volumetric and global compression efficiencies is proposed for propane DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002884

R32 partial condensation inside a brazed plate heat exchanger / Simone Mancin 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. 601–611 Titre : R32 partial condensation inside a brazed plate heat exchanger Titre original : Condensation partielle du R32 à l'intérieur d'un échangeur de chaleur à plaques brasées Type de document : texte imprimé Auteurs : Simone Mancin, Auteur ; Davide Del Col, Auteur ; Luisa Rossetto, Auteur Année de publication : 2013 Article en page(s) : pp. 601–611 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Plate;  Condensation;  Superheating;  R32;  R410A;  Carbon  dioxide  (CO2) Résumé : This paper presents recent measurements of heat transfer coefficient obtained during condensation of R32 inside a commercial brazed plate heat exchanger (BPHE). The experimental data show the effect of refrigerant mass velocity, vapor quality, temperature difference (saturation-to-wall) and inlet vapor superheating. In particular, the specific mass velocity is varied between 15 and 40 kg m−2 s−1 and the outlet vapor quality between 0.0 and 0.65, while inlet vapor superheating goes from 5 to 25 K. The saturation temperature is kept constant at around 36.5 °C, which can be considered a usual temperature level for water cooled heat pump applications. The present authors provide a numerical procedure to calculate the condensation heat transfer in the BPHE, accounting also for the superheating effect. This model is assessed by comparisons with the experimental measurements relative to R32, R410A, and R744. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712002794 [article] R32 partial condensation inside a brazed plate heat exchanger = Condensation partielle du R32 à l'intérieur d'un échangeur de chaleur à plaques brasées [texte imprimé] / Simone Mancin, Auteur ; Davide Del Col, Auteur ; Luisa Rossetto, Auteur . - 2013 . - pp. 601–611. Refrigeration Langues : Anglais (eng) in International journal of refrigeration > Vol. 36 N° 2 (N° spécial) (Mars 2013) . - pp. 601–611 Mots-clés : Plate;  Condensation;  Superheating;  R32;  R410A;  Carbon  dioxide  (CO2) Résumé : This paper presents recent measurements of heat transfer coefficient obtained during condensation of R32 inside a commercial brazed plate heat exchanger (BPHE). The experimental data show the effect of refrigerant mass velocity, vapor quality, temperature difference (saturation-to-wall) and inlet vapor superheating. In particular, the specific mass velocity is varied between 15 and 40 kg m−2 s−1 and the outlet vapor quality between 0.0 and 0.65, while inlet vapor superheating goes from 5 to 25 K. The saturation temperature is kept constant at around 36.5 °C, which can be considered a usual temperature level for water cooled heat pump applications. The present authors provide a numerical procedure to calculate the condensation heat transfer in the BPHE, accounting also for the superheating effect. This model is assessed by comparisons with the experimental measurements relative to R32, R410A, and R744. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712002794