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

Heat transfer and pressure drop during hydrocarbon refrigerant condensation inside a brazed plate heat exchanger / Giovanni A. Longo in International journal of refrigeration, Vol. 33 N° 5 (Août 2010) 

Public ISBD [article]  in International journal of refrigeration > Vol. 33 N° 5 (Août 2010) . - pp. 944-953 Titre : Heat transfer and pressure drop during hydrocarbon refrigerant condensation inside a brazed plate heat exchanger Titre original : Transfert de chaleur et chute de pression des frigorigènes hydrocarbures à l'intérieur d'un échangeur de chaleur à plaques brasées Type de document : texte imprimé Auteurs : Giovanni A. Longo, Auteur Année de publication : 2010 Article en page(s) : pp. 944-953 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Heat  exchanger  Plate  exchanger  Condensation  Hydrocarbon  Heat  exchange  Heat  transfer  Pressure  drop Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : This paper presents the heat transfer coefficients and pressure drop measured during HC-600a, HC-290 and HC-1270 saturated vapour condensation inside a brazed plate heat exchanger: the effects of refrigerant mass flux, saturation temperature (pressure) and fluid properties are investigated. The heat transfer coefficients show weak sensitivity to saturation temperature (pressure) and great sensitivity to refrigerant mass flux and fluid properties. A transition point between gravity controlled and forced convection condensation has been found for a refrigerant mass flux around 15–18 kg m−2 s−1. In the forced convection condensation region the heat transfer coefficients show a 35–40% enhancement for a 60% increase of the refrigerant mass flux. The frictional pressure drop shows a linear dependence on the kinetic energy per unit volume of the refrigerant flow. HC-1270 shows heat transfer coefficients 5% higher than HC-600a and 10–15% higher than HC-290, together with frictional pressure drop 20–25% lower than HC-290 and 50–66% lower than HC-600a. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710000435 [article] Heat transfer and pressure drop during hydrocarbon refrigerant condensation inside a brazed plate heat exchanger = Transfert de chaleur et chute de pression des frigorigènes hydrocarbures à l'intérieur d'un échangeur de chaleur à plaques brasées [texte imprimé] / Giovanni A. Longo, Auteur . - 2010 . - pp. 944-953. Génie Mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 33 N° 5 (Août 2010) . - pp. 944-953 Mots-clés : Heat  exchanger  Plate  exchanger  Condensation  Hydrocarbon  Heat  exchange  Heat  transfer  Pressure  drop Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : This paper presents the heat transfer coefficients and pressure drop measured during HC-600a, HC-290 and HC-1270 saturated vapour condensation inside a brazed plate heat exchanger: the effects of refrigerant mass flux, saturation temperature (pressure) and fluid properties are investigated. The heat transfer coefficients show weak sensitivity to saturation temperature (pressure) and great sensitivity to refrigerant mass flux and fluid properties. A transition point between gravity controlled and forced convection condensation has been found for a refrigerant mass flux around 15–18 kg m−2 s−1. In the forced convection condensation region the heat transfer coefficients show a 35–40% enhancement for a 60% increase of the refrigerant mass flux. The frictional pressure drop shows a linear dependence on the kinetic energy per unit volume of the refrigerant flow. HC-1270 shows heat transfer coefficients 5% higher than HC-600a and 10–15% higher than HC-290, together with frictional pressure drop 20–25% lower than HC-290 and 50–66% lower than HC-600a. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710000435