Giuseppe Franchini | Università degli Studi di Bergamo (University of Bergamo) (original) (raw)
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Papers by Giuseppe Franchini
The present work reports the main issues of coupling solar collectors and cogeneration units for ... more The present work reports the main issues of coupling solar collectors and cogeneration units for heating and cooling purposes which have been derived from the detailed analysis of a study case. The work suggests a procedure for planning such systems so that solar collectors and a cogenerator do not interfere in their respective operation. The procedure includes the selection of
International Journal of Heat and Fluid Flow, 2010
The present paper shows the results of an experimental investigation into a nozzle vane cascade w... more The present paper shows the results of an experimental investigation into a nozzle vane cascade with endwall contouring and film cooling. In a film cooled endwall the front area, especially close to the leading edge, is one of the most critical regions to be cooled; in case of a contoured endwall the thermal protection becomes even more difficult because of the endwall curvature effect. Two film cooling hole geometries with four rows of holes were tested: cylindrical holes and conical expanded holes. Tests were performed at low speed (M 2is = 0.2) and low inlet turbulence intensity level, with coolant to main stream mass flow ratio varied within the 0.5-2.5% range. Aerodynamic and thermal performances were evaluated in every injection condition. Compared to cylindrical holes, results showed that shaped film cooling holes generate slightly higher secondary losses and provide a better thermal coverage, at the expense of a higher coolant flow injection.
Im Herbst 2007 wurde das durch die EU unterstützte Projekt SolarCombi+ gestartet. Ziel des Projek... more Im Herbst 2007 wurde das durch die EU unterstützte Projekt SolarCombi+ gestartet. Ziel des Projektes ist es den Markteintritt von Solar Kombi Plus Systeme (Systeme zur Warmwassererwärmung, Raumheizung und Raumkühlung kleiner Leistung) zu unterstützen. Hierzu werden zu Beginn Marktanalysen durchgeführt um die Marktnischen mit dem größten Potential zu identifizieren. Darauf aufbauend werden Modellierungen von Solar Kombi Plus Systemen durchgeführt und technisch und ökonomisch analysiert. Im vorliegenden Dokument werden in der einer Einführung, Europäische Daten es Air Conditioning Marktes aufgezeigt und die Ergebnisse der Firmenbefragung vorgestellt. Es folgen Überlegungen zur Grundlage der Wahl von hydraulischen Schemen von standardisierten Anwendungen und eine Diskussion über die gewählten Gebäudetypologien und Klimata für die Modellierungen. Abschließend werden die beiden hydraulischen Grundschemen vorgestellt und ein Ausblick auf die zu erwartenden Modellierungsergebnisse gegeben. Weitere Informationen befinden sich auf der Homepage www.solarcombiplus.eu
... execution and for the performance evaluation of the considered chiller. In particular, the UN... more ... execution and for the performance evaluation of the considered chiller. In particular, the UNI EN 14511 (dedicated to electrically driven heat pumps) and ANSI/ARI Standard 560 (dedicated to absorption chiller) were taken into consideration. ...
In autumn 2007 the European project SolarCombi+ has been started. The aim of this project is to t... more In autumn 2007 the European project SolarCombi+ has been started. The aim of this project is to take newly commercially available small scale sorption chillers and identify and promote standardised Solar Combi+ systems for small applications: i.e. combined solar water and space heating and cooling up to a cooling load of 20 kW. A thorough market study at project start
Journal of Turbomachinery-transactions of The Asme, 2007
ABSTRACT
Journal of Turbomachinery-transactions of The Asme, 2006
ABSTRACT
On the subject of high energy efficiency systems, the present work focuses on Combined Heating, C... more On the subject of high energy efficiency systems, the present work focuses on Combined Heating, Cooling and Power (CHCP) plants, made up of gas engine as prime mover and absorption chiller as cooling device, combined with Evacuated Tube solar thermal Collectors (ETC).
The paper reports the results of a performance analysis of an integrated cooling-desalination sys... more The paper reports the results of a performance analysis of an integrated cooling-desalination system driven by solar energy. In typical solar cooling plants, solar energy is used to drive absorption chillers providing cooling energy. Due to relatively low COP values, a large amount of heat is rejected from the chiller at low temperature. Such low grade heat can be properly used to drive a low temperature HD (Humidification-Dehumidification) desalinator. Two simulation procedures have been developed to model the absorption chiller and the HD desalinator under design and off-design conditions. By using such codes, the performance of the system has been investigated for a 50 kW cooling capacity, by varying temperature and mass flow rate of the sea water. Such procedures have been also included within TRNSYS environment to perform a transient simulation of the system, composed by a lithium-bromide absorption chiller, a solar collector field, an hot storage tank and an HD desalination unit. The plant off-design simulation has been carried out for typical meteorological conditions of Southern Italy, with ambient temperature and solar radiation variations, on a daily base.
Journal of Turbomachinery-transactions of The Asme, 2010
ABSTRACT The present paper investigates the effects of endwall injection of cooling flow on the a... more ABSTRACT The present paper investigates the effects of endwall injection of cooling flow on the aerodynamic performance of a nozzle vane cascade with endwall contouring. Tests have been performed on a 7 vane cascade with a geometry typical of a real gas turbine nozzle vane. The cooling scheme consists of four rows of cylindrical holes. The same cooling scheme, applied to a flat endwall, was already investigated by the authors. Tests have been carried out at low speed (M2is = 0.2) with a low inlet turbulence intensity level (1.0%) and with a coolant to mainstream mass flow ratio varied in the range from zero (solid endwall) to 2.5%. Energy loss coefficient, secondary vorticity and outlet angle distributions were computed from 5-hole probe measured data. Contoured endwall results, with and without film cooling, were compared to planar endwall data. Endwall contouring was responsible for a significant overall loss decrease, thanks to the reduction of both profile and planar side secondary flows losses; a loss increase on the contoured side was instead observed. Like as for the planar endwall, even for contoured endwall coolant injection modifies secondary flows, reducing their intensity, but the relevance of the changes is reduced. Nevertheless for all the tested injection conditions, secondary losses on the contoured side are always higher than in the planar case, while contoured cascade overall losses are lower. A unique minimum overall loss injection condition was found for both tested geometries, corresponding to an injected mass flow rate of about 1.0%.
The present work reports the main issues of coupling solar collectors and cogeneration units for ... more The present work reports the main issues of coupling solar collectors and cogeneration units for heating and cooling purposes which have been derived from the detailed analysis of a study case. The work suggests a procedure for planning such systems so that solar collectors and a cogenerator do not interfere in their respective operation. The procedure includes the selection of
International Journal of Heat and Fluid Flow, 2010
The present paper shows the results of an experimental investigation into a nozzle vane cascade w... more The present paper shows the results of an experimental investigation into a nozzle vane cascade with endwall contouring and film cooling. In a film cooled endwall the front area, especially close to the leading edge, is one of the most critical regions to be cooled; in case of a contoured endwall the thermal protection becomes even more difficult because of the endwall curvature effect. Two film cooling hole geometries with four rows of holes were tested: cylindrical holes and conical expanded holes. Tests were performed at low speed (M 2is = 0.2) and low inlet turbulence intensity level, with coolant to main stream mass flow ratio varied within the 0.5-2.5% range. Aerodynamic and thermal performances were evaluated in every injection condition. Compared to cylindrical holes, results showed that shaped film cooling holes generate slightly higher secondary losses and provide a better thermal coverage, at the expense of a higher coolant flow injection.
Im Herbst 2007 wurde das durch die EU unterstützte Projekt SolarCombi+ gestartet. Ziel des Projek... more Im Herbst 2007 wurde das durch die EU unterstützte Projekt SolarCombi+ gestartet. Ziel des Projektes ist es den Markteintritt von Solar Kombi Plus Systeme (Systeme zur Warmwassererwärmung, Raumheizung und Raumkühlung kleiner Leistung) zu unterstützen. Hierzu werden zu Beginn Marktanalysen durchgeführt um die Marktnischen mit dem größten Potential zu identifizieren. Darauf aufbauend werden Modellierungen von Solar Kombi Plus Systemen durchgeführt und technisch und ökonomisch analysiert. Im vorliegenden Dokument werden in der einer Einführung, Europäische Daten es Air Conditioning Marktes aufgezeigt und die Ergebnisse der Firmenbefragung vorgestellt. Es folgen Überlegungen zur Grundlage der Wahl von hydraulischen Schemen von standardisierten Anwendungen und eine Diskussion über die gewählten Gebäudetypologien und Klimata für die Modellierungen. Abschließend werden die beiden hydraulischen Grundschemen vorgestellt und ein Ausblick auf die zu erwartenden Modellierungsergebnisse gegeben. Weitere Informationen befinden sich auf der Homepage www.solarcombiplus.eu
... execution and for the performance evaluation of the considered chiller. In particular, the UN... more ... execution and for the performance evaluation of the considered chiller. In particular, the UNI EN 14511 (dedicated to electrically driven heat pumps) and ANSI/ARI Standard 560 (dedicated to absorption chiller) were taken into consideration. ...
In autumn 2007 the European project SolarCombi+ has been started. The aim of this project is to t... more In autumn 2007 the European project SolarCombi+ has been started. The aim of this project is to take newly commercially available small scale sorption chillers and identify and promote standardised Solar Combi+ systems for small applications: i.e. combined solar water and space heating and cooling up to a cooling load of 20 kW. A thorough market study at project start
Journal of Turbomachinery-transactions of The Asme, 2007
ABSTRACT
Journal of Turbomachinery-transactions of The Asme, 2006
ABSTRACT
On the subject of high energy efficiency systems, the present work focuses on Combined Heating, C... more On the subject of high energy efficiency systems, the present work focuses on Combined Heating, Cooling and Power (CHCP) plants, made up of gas engine as prime mover and absorption chiller as cooling device, combined with Evacuated Tube solar thermal Collectors (ETC).
The paper reports the results of a performance analysis of an integrated cooling-desalination sys... more The paper reports the results of a performance analysis of an integrated cooling-desalination system driven by solar energy. In typical solar cooling plants, solar energy is used to drive absorption chillers providing cooling energy. Due to relatively low COP values, a large amount of heat is rejected from the chiller at low temperature. Such low grade heat can be properly used to drive a low temperature HD (Humidification-Dehumidification) desalinator. Two simulation procedures have been developed to model the absorption chiller and the HD desalinator under design and off-design conditions. By using such codes, the performance of the system has been investigated for a 50 kW cooling capacity, by varying temperature and mass flow rate of the sea water. Such procedures have been also included within TRNSYS environment to perform a transient simulation of the system, composed by a lithium-bromide absorption chiller, a solar collector field, an hot storage tank and an HD desalination unit. The plant off-design simulation has been carried out for typical meteorological conditions of Southern Italy, with ambient temperature and solar radiation variations, on a daily base.
Journal of Turbomachinery-transactions of The Asme, 2010
ABSTRACT The present paper investigates the effects of endwall injection of cooling flow on the a... more ABSTRACT The present paper investigates the effects of endwall injection of cooling flow on the aerodynamic performance of a nozzle vane cascade with endwall contouring. Tests have been performed on a 7 vane cascade with a geometry typical of a real gas turbine nozzle vane. The cooling scheme consists of four rows of cylindrical holes. The same cooling scheme, applied to a flat endwall, was already investigated by the authors. Tests have been carried out at low speed (M2is = 0.2) with a low inlet turbulence intensity level (1.0%) and with a coolant to mainstream mass flow ratio varied in the range from zero (solid endwall) to 2.5%. Energy loss coefficient, secondary vorticity and outlet angle distributions were computed from 5-hole probe measured data. Contoured endwall results, with and without film cooling, were compared to planar endwall data. Endwall contouring was responsible for a significant overall loss decrease, thanks to the reduction of both profile and planar side secondary flows losses; a loss increase on the contoured side was instead observed. Like as for the planar endwall, even for contoured endwall coolant injection modifies secondary flows, reducing their intensity, but the relevance of the changes is reduced. Nevertheless for all the tested injection conditions, secondary losses on the contoured side are always higher than in the planar case, while contoured cascade overall losses are lower. A unique minimum overall loss injection condition was found for both tested geometries, corresponding to an injected mass flow rate of about 1.0%.