Documents disponibles écrits par cet auteur

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

Improved rotary vane expander for trans-critical CO2 cycle by introducing high-pressure gas into the vane slots / Xiaohan Jia 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. 732-741 Titre : Improved rotary vane expander for trans-critical CO2 cycle by introducing high-pressure gas into the vane slots Titre original : Machine de détente à pales rotatives pour un cycle au CO2 transcritique, avec introduction de gaz sous pression élevée dans les ouvertures Type de document : texte imprimé Auteurs : Xiaohan Jia, Auteur ; Bo Zhang, Auteur ; Silvia Minetto, Auteur Année de publication : 2011 Article en page(s) : pp. 732-741 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Carbon  dioxide  Transcritical  cycle  Expansion  Device  Energy  recovery  Friction Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : The loss of contact between the vane tip and cylinder wall was proven to cause a serious leakage and inefficient operation of the rotary vane expander, which was developed to replace the throttling valve in the trans-critical CO2 refrigeration system. An improved structure was suggested by introducing high-pressure gas into the vane slots. This paper presents the experimental investigation of the improved prototype expander. By comparing the improved prototype with the original, focusing on the expander performance and the p–θ diagram as well as the vane movement, the effects of introducing high-pressure gas into the slots on the thermodynamic processes and performance were analyzed. The results showed that, by introducing the high-pressure gas into the vane slots, the volumetric efficiency was increased from 17% to 35%, and the isentropic efficiency improved from 15% to 45%, resulting in a maximum COP improvement of 27.2% compared to the throttling cycle under the same working conditions. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002793 [article] Improved rotary vane expander for trans-critical CO2 cycle by introducing high-pressure gas into the vane slots = Machine de détente à pales rotatives pour un cycle au CO2 transcritique, avec introduction de gaz sous pression élevée dans les ouvertures [texte imprimé] / Xiaohan Jia, Auteur ; Bo Zhang, Auteur ; Silvia Minetto, Auteur . - 2011 . - pp. 732-741. Génie Mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 34 N° 3 (Mai 2011) . - pp. 732-741 Mots-clés : Carbon  dioxide  Transcritical  cycle  Expansion  Device  Energy  recovery  Friction Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : The loss of contact between the vane tip and cylinder wall was proven to cause a serious leakage and inefficient operation of the rotary vane expander, which was developed to replace the throttling valve in the trans-critical CO2 refrigeration system. An improved structure was suggested by introducing high-pressure gas into the vane slots. This paper presents the experimental investigation of the improved prototype expander. By comparing the improved prototype with the original, focusing on the expander performance and the p–θ diagram as well as the vane movement, the effects of introducing high-pressure gas into the slots on the thermodynamic processes and performance were analyzed. The results showed that, by introducing the high-pressure gas into the vane slots, the volumetric efficiency was increased from 17% to 35%, and the isentropic efficiency improved from 15% to 45%, resulting in a maximum COP improvement of 27.2% compared to the throttling cycle under the same working conditions. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002793

Theoretical and experimental analysis of a CO2 heat pump for domestic hot water / Silvia Minetto 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. 742-751 Titre : Theoretical and experimental analysis of a CO2 heat pump for domestic hot water Titre original : Etude théorique et expérimentale sur une pompe à chaleur au CO2 utilisée pour l'eau chaude sanitaire Type de document : texte imprimé Auteurs : Silvia Minetto, Auteur Année de publication : 2011 Article en page(s) : pp. 742-751 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Carbon  dioxide  Heat  pump  Hot  water  Optimisation  Cycle  Transcritical Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : This paper describes the development of a CO2 air/water heat pump for the production of tap hot water in a residential building. The basic design consists of a single-stage piston compressor, a coaxial type gas cooler, an electronic expansion valve, a finned tube evaporator and a low pressure receiver. The heat pump is combined with a storage tank designed to maintain internal water stratification. The gas cooler pressure optimisation in the case of fixed water delivery temperature was theoretically analysed. A new control method for the upper cycle pressure was developed to maximise the COP of the heat pump, while the water mass flow was adjusted to maintain the set water temperature at the gas cooler exit. Before commissioning, the heat pump was factory tested to verify its energy performance and to validate the high pressure control logic. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002938 [article] Theoretical and experimental analysis of a CO2 heat pump for domestic hot water = Etude théorique et expérimentale sur une pompe à chaleur au CO2 utilisée pour l'eau chaude sanitaire [texte imprimé] / Silvia Minetto, Auteur . - 2011 . - pp. 742-751. Génie Mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 34 N° 3 (Mai 2011) . - pp. 742-751 Mots-clés : Carbon  dioxide  Heat  pump  Hot  water  Optimisation  Cycle  Transcritical Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : This paper describes the development of a CO2 air/water heat pump for the production of tap hot water in a residential building. The basic design consists of a single-stage piston compressor, a coaxial type gas cooler, an electronic expansion valve, a finned tube evaporator and a low pressure receiver. The heat pump is combined with a storage tank designed to maintain internal water stratification. The gas cooler pressure optimisation in the case of fixed water delivery temperature was theoretically analysed. A new control method for the upper cycle pressure was developed to maximise the COP of the heat pump, while the water mass flow was adjusted to maintain the set water temperature at the gas cooler exit. Before commissioning, the heat pump was factory tested to verify its energy performance and to validate the high pressure control logic. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002938

Thermodynamic analysis and experimental investigation of a CO2 household heat pump dryer / Ferdinando Mancini in International journal of refrigeration, Vol. 34 N° 4 (Juin 2011) 

Public ISBD [article]  in International journal of refrigeration > Vol. 34 N° 4 (Juin 2011) . - pp. 851-858 Titre : Thermodynamic analysis and experimental investigation of a CO2 household heat pump dryer Titre original : Analyse thermodynamique et ètude expèrimentale sur un sèche-linge domestique à pompe à chaleur au CO2 Type de document : texte imprimé Auteurs : Ferdinando Mancini, Auteur ; Silvia Minetto, Auteur ; Ezio Fornasieri, Auteur Année de publication : 2011 Article en page(s) : pp. 851-858 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Carbon  dioxide  Cycle  Transcritical  Heat  pump  Dryer Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : Carbon dioxide is regarded as an optimal working fluid for heat pump dryers. The transcritical cycle well fits the closed-loop drying process which requires dehumidification and re-heating according to high temperature lift of the air stream. In this paper, the transcritical CO2 cycle is compared with a sub-critical R134a cycle. The theoretical analysis is based on fixed temperature approach values at the heat exchangers. The study considers optimal high pressure for the transcritical cycle and optimal refrigerant subcooling for the sub-critical cycle. The theoretical analysis investigates the energy performance of the thermodynamic cycle as a function of the temperature and mass flow rate of the drying air. The optimisation of the operating conditions for CO2 involves lower air temperature than in the case of R134a; this conditions can be satisfied by a suitable design of the appliance, whose thermal balance is achieved when the dissipated heat corresponds to the work spent by the compressor and the fan; the air temperature is a floating variable that adjusts its value to comply with the thermal balance. Experimental results, conducted on a prototype, give a positive assessment for CO2 as working fluid for heat pump dryers: a negligible decrease in the electric power consumption, with a limited (+9%) increase in the cycle time, is shown in comparison with the reference R134a heat pump dryer. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002872 [article] Thermodynamic analysis and experimental investigation of a CO2 household heat pump dryer = Analyse thermodynamique et ètude expèrimentale sur un sèche-linge domestique à pompe à chaleur au CO2 [texte imprimé] / Ferdinando Mancini, Auteur ; Silvia Minetto, Auteur ; Ezio Fornasieri, Auteur . - 2011 . - pp. 851-858. Génie Mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 34 N° 4 (Juin 2011) . - pp. 851-858 Mots-clés : Carbon  dioxide  Cycle  Transcritical  Heat  pump  Dryer Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : Carbon dioxide is regarded as an optimal working fluid for heat pump dryers. The transcritical cycle well fits the closed-loop drying process which requires dehumidification and re-heating according to high temperature lift of the air stream. In this paper, the transcritical CO2 cycle is compared with a sub-critical R134a cycle. The theoretical analysis is based on fixed temperature approach values at the heat exchangers. The study considers optimal high pressure for the transcritical cycle and optimal refrigerant subcooling for the sub-critical cycle. The theoretical analysis investigates the energy performance of the thermodynamic cycle as a function of the temperature and mass flow rate of the drying air. The optimisation of the operating conditions for CO2 involves lower air temperature than in the case of R134a; this conditions can be satisfied by a suitable design of the appliance, whose thermal balance is achieved when the dissipated heat corresponds to the work spent by the compressor and the fan; the air temperature is a floating variable that adjusts its value to comply with the thermal balance. Experimental results, conducted on a prototype, give a positive assessment for CO2 as working fluid for heat pump dryers: a negligible decrease in the electric power consumption, with a limited (+9%) increase in the cycle time, is shown in comparison with the reference R134a heat pump dryer. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002872