Dépouillements

Solid sorption cycles / R.E. Critoph in International journal of refrigeration, Vol. 35 N° 3 (Mai 2012) 

Public ISBD [article]  in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 490–493 Titre : Solid sorption cycles : A short history Titre original : Cycles à sorption solide : bref historique Type de document : texte imprimé Auteurs : R.E. Critoph, Auteur Année de publication : 2012 Article en page(s) : pp. 490–493 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Adsorption  Heat  pump  Refrigerator  Air  conditioning  History ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712000515 [article] Solid sorption cycles = Cycles à sorption solide : bref historique : A short history [texte imprimé] / R.E. Critoph, Auteur . - 2012 . - pp. 490–493. Génie mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 490–493 Mots-clés : Adsorption  Heat  pump  Refrigerator  Air  conditioning  History ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712000515

Experimental study on adsorption–desorption characteristics of granular activated carbon/R134a pair / Ahmed A. Askalany in International journal of refrigeration, Vol. 35 N° 3 (Mai 2012) 

Public ISBD [article]  in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 494–498 Titre : Experimental study on adsorption–desorption characteristics of granular activated carbon/R134a pair Titre original : Etude expérimentale sur les caractéristiques d'adsorption / désorption d'un couple actif charbon actif granulé/R134a Type de document : texte imprimé Auteurs : Ahmed A. Askalany, Auteur ; Salem, M., Auteur ; I.M. Ismail, Auteur Année de publication : 2012 Article en page(s) : pp. 494–498 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Adsorption  Activated  carbon  Cooling  R134a Résumé : Experimental runs were done to estimate the adsorption characteristics of granular activated carbon (GAC)/R134a pair. A laboratory scale test rig was designed and built to run the experiments. The adsorption capacity of the GAC was studied at different temperatures 25 °C, 35 °C, 45 °C and 65 °C. Pressure and time were recorded during the experiments. The maximum adsorption capacity was found to be 1.68 kgR134a kgcarbon−1 at 25 °C after 1000 s. The activation energy and the exponential constant were estimated to be 9575 J mol−1 and 1.83 respectively. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711000843 [article] Experimental study on adsorption–desorption characteristics of granular activated carbon/R134a pair = Etude expérimentale sur les caractéristiques d'adsorption / désorption d'un couple actif charbon actif granulé/R134a [texte imprimé] / Ahmed A. Askalany, Auteur ; Salem, M., Auteur ; I.M. Ismail, Auteur . - 2012 . - pp. 494–498. Génie mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 494–498 Mots-clés : Adsorption  Activated  carbon  Cooling  R134a Résumé : Experimental runs were done to estimate the adsorption characteristics of granular activated carbon (GAC)/R134a pair. A laboratory scale test rig was designed and built to run the experiments. The adsorption capacity of the GAC was studied at different temperatures 25 °C, 35 °C, 45 °C and 65 °C. Pressure and time were recorded during the experiments. The maximum adsorption capacity was found to be 1.68 kgR134a kgcarbon−1 at 25 °C after 1000 s. The activation energy and the exponential constant were estimated to be 9575 J mol−1 and 1.83 respectively. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711000843

Accurate adsorption isotherms of R134a onto activated carbons for cooling and freezing applications / Bidyut Baran Saha in International journal of refrigeration, Vol. 35 N° 3 (Mai 2012) 

Public ISBD [article]  in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 499–505 Titre : Accurate adsorption isotherms of R134a onto activated carbons for cooling and freezing applications Titre original : Isothermes d'adsorption précises pour le R134a sur du charbon actif dans les applications de refroidissement et de congélation Type de document : texte imprimé Auteurs : Bidyut Baran Saha, Auteur ; Ibrahim I. El-Sharkawy, Auteur ; Roger Thorpe, Auteur Année de publication : 2012 Article en page(s) : pp. 499–505 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Activated  carbon  Adsorption  isotherm  Cooling  R134a Résumé : The objective of this article is to improve the performance of thermally powered adsorption/cooling systems by selecting a new adsorbent/refrigerant pair. Adsorption equilibrium data of R134a onto granular activated carbon (AC) and Unitika activated carbon fiber (ACF) of type (A-20) have been measured experimentally using Rubotherm ISOSORP 2000 within evaporation temperatures range between −20 and 40 °C and adsorption temperatures range from 30 to 80 °C. Experimental data have been correlated using various popular isotherm models. The isosteric heat of adsorption of the assorted adsorbent/refrigerant pairs has also been extracted from the present experimental data. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711001083 [article] Accurate adsorption isotherms of R134a onto activated carbons for cooling and freezing applications = Isothermes d'adsorption précises pour le R134a sur du charbon actif dans les applications de refroidissement et de congélation [texte imprimé] / Bidyut Baran Saha, Auteur ; Ibrahim I. El-Sharkawy, Auteur ; Roger Thorpe, Auteur . - 2012 . - pp. 499–505. Génie mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 499–505 Mots-clés : Activated  carbon  Adsorption  isotherm  Cooling  R134a Résumé : The objective of this article is to improve the performance of thermally powered adsorption/cooling systems by selecting a new adsorbent/refrigerant pair. Adsorption equilibrium data of R134a onto granular activated carbon (AC) and Unitika activated carbon fiber (ACF) of type (A-20) have been measured experimentally using Rubotherm ISOSORP 2000 within evaporation temperatures range between −20 and 40 °C and adsorption temperatures range from 30 to 80 °C. Experimental data have been correlated using various popular isotherm models. The isosteric heat of adsorption of the assorted adsorbent/refrigerant pairs has also been extracted from the present experimental data. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711001083

Heat and mass transfer studies on compact generator of R134a/DMF vapour absorption refrigeration system / P. Balamurugan in International journal of refrigeration, Vol. 35 N° 3 (Mai 2012) 

Public ISBD [article]  in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 506–517 Titre : Heat and mass transfer studies on compact generator of R134a/DMF vapour absorption refrigeration system Titre original : Etudes sur le transfert de chaleur et de masse dans un système frigorifique compact à absorption de vapeur au R134a/DMF Type de document : texte imprimé Auteurs : P. Balamurugan, Auteur ; A. Mani, Auteur Année de publication : 2012 Article en page(s) : pp. 506–517 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : R134a  DMF  Generator  Absorption  system  Heat  transfer  Mass  transfer Résumé : Experimental investigation on the performance of compact generator of R134a/DMF vapour absorption refrigeration system is presented. The system uses brazed plate heat exchangers as generator, condenser, absorber, evaporator and solution heat exchanger and has a rated cooling capacity of 1 kW. The influence of driving temperature ratio, driving pressure ratio, R134a mass fraction and solution two phase Reynolds number is studied. This kind of system can be operated with low grade thermal energy such as solar energy, waste heat, etc. The generator temperature is chosen accordingly between 353 K and 368 K. Desorption ratio and Sherwood number increase as the solution Reynolds number, solution initial mass fraction, and driving temperature ratio increase whereas they decrease as the driving pressure ratio increases. The performance of the compact generator at different operating conditions is presented. Based on the present data, empirical correlations for Nusselt number and Sherwood number are proposed. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712000102 [article] Heat and mass transfer studies on compact generator of R134a/DMF vapour absorption refrigeration system = Etudes sur le transfert de chaleur et de masse dans un système frigorifique compact à absorption de vapeur au R134a/DMF [texte imprimé] / P. Balamurugan, Auteur ; A. Mani, Auteur . - 2012 . - pp. 506–517. Génie mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 506–517 Mots-clés : R134a  DMF  Generator  Absorption  system  Heat  transfer  Mass  transfer Résumé : Experimental investigation on the performance of compact generator of R134a/DMF vapour absorption refrigeration system is presented. The system uses brazed plate heat exchangers as generator, condenser, absorber, evaporator and solution heat exchanger and has a rated cooling capacity of 1 kW. The influence of driving temperature ratio, driving pressure ratio, R134a mass fraction and solution two phase Reynolds number is studied. This kind of system can be operated with low grade thermal energy such as solar energy, waste heat, etc. The generator temperature is chosen accordingly between 353 K and 368 K. Desorption ratio and Sherwood number increase as the solution Reynolds number, solution initial mass fraction, and driving temperature ratio increase whereas they decrease as the driving pressure ratio increases. The performance of the compact generator at different operating conditions is presented. Based on the present data, empirical correlations for Nusselt number and Sherwood number are proposed. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712000102

Experimental testing of a lab-scale adsorption chiller using a novel selective water sorbent “silica modified by calcium nitrate” / Angelo Freni in International journal of refrigeration, Vol. 35 N° 3 (Mai 2012) 

Public ISBD [article]  in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 518–524 Titre : Experimental testing of a lab-scale adsorption chiller using a novel selective water sorbent “silica modified by calcium nitrate” Titre original : Essais expérimentaux sur un refroidisseur à adsorption à l'échelle du laboratoire employant un sorbant d'eau à base de gel de silice modifié à l'aide du nitrate de calcium Type de document : texte imprimé Auteurs : Angelo Freni, Auteur ; Alessio Sapienza, Auteur ; Ivan S. Glaznev, Auteur Année de publication : 2012 Article en page(s) : pp. 518–524 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Adsorption  chiller  Water  Silica  gel  Additive  Nitrate  Calcium  Evaluation  Performance Résumé : In this paper, a novel composite water sorbent “silica modified by calcium nitrate” (SWS-8L) has been tested for utilization in adsorption chillers driven by low-temperature heat. The isosteric diagram of the working pair under investigation has been calculated from experimental adsorption data measured at equilibrium. The equivalent specific heat of the sorbent as a function of the water loading was experimentally measured by a calorimetric technique. Thermodynamic cooling COP was estimated to be 0.51–0.71, with desorption temperature lower than 90 °C. Real performance was measured by testing a SWS-8L based sorbent bed in a lab-scale adsorption chiller. With this aim, SWS-8L grains were embedded inside a compact aluminium heat exchanger with high thermal efficiency. Experimental cooling COP, mass specific cooling power SCP and volumetric specific cooling power VSCP obtained are 0.18–0.31 (cycle time 10 min), 190–389 W/kg dry sorbent and 104–212 W/dm3, respectively. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710001131 [article] Experimental testing of a lab-scale adsorption chiller using a novel selective water sorbent “silica modified by calcium nitrate” = Essais expérimentaux sur un refroidisseur à adsorption à l'échelle du laboratoire employant un sorbant d'eau à base de gel de silice modifié à l'aide du nitrate de calcium [texte imprimé] / Angelo Freni, Auteur ; Alessio Sapienza, Auteur ; Ivan S. Glaznev, Auteur . - 2012 . - pp. 518–524. Génie mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 518–524 Mots-clés : Adsorption  chiller  Water  Silica  gel  Additive  Nitrate  Calcium  Evaluation  Performance Résumé : In this paper, a novel composite water sorbent “silica modified by calcium nitrate” (SWS-8L) has been tested for utilization in adsorption chillers driven by low-temperature heat. The isosteric diagram of the working pair under investigation has been calculated from experimental adsorption data measured at equilibrium. The equivalent specific heat of the sorbent as a function of the water loading was experimentally measured by a calorimetric technique. Thermodynamic cooling COP was estimated to be 0.51–0.71, with desorption temperature lower than 90 °C. Real performance was measured by testing a SWS-8L based sorbent bed in a lab-scale adsorption chiller. With this aim, SWS-8L grains were embedded inside a compact aluminium heat exchanger with high thermal efficiency. Experimental cooling COP, mass specific cooling power SCP and volumetric specific cooling power VSCP obtained are 0.18–0.31 (cycle time 10 min), 190–389 W/kg dry sorbent and 104–212 W/dm3, respectively. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710001131

Reallocation of adsorption and desorption times for optimisation of cooling cycles / Yu.I. Aristov in International journal of refrigeration, Vol. 35 N° 3 (Mai 2012) 

Public ISBD [article]  in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 525–531 Titre : Reallocation of adsorption and desorption times for optimisation of cooling cycles Titre original : Optimisation des cycles de refroidissement par modification des durées d'adsorption et de désorption Type de document : texte imprimé Auteurs : Yu.I. Aristov, Auteur ; A. Sapienza, Auteur ; D.S. Ovoshchnikov, Auteur Année de publication : 2012 Article en page(s) : pp. 525–531 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Adsorption  system  Variation  Duration  Cycle-adsorption  Desorption  Optimisation  COP  Water Résumé : In an adsorption cycle it is common to have an equal duration of the adsorption and desorption phases. In this paper, we investigated an intermittent cooling cycle with variable adsorption/desorption duration at fixed total cycle time. A new composite, LiNO3/silica KSK (SWS-9L), was used as a water sorbent. It was specifically synthesised for adsorptive chilling units driven by low temperature heat (65–75 °C). The sorption equilibrium and dynamics of SWS-9L were studied under conditions close to those realized in a typical cooling cycle. The actual performance of SWS-9L was tested in a single bed adsorption chiller with special emphasis on the optimisation of the relative duration of isobaric adsorption and desorption stages to maximize the Coefficient Of Performance and the Specific Cooling Power of the cycle. The tests resulted in being able to make practical recommendations to rationally optimise the relative duration of adsorption and desorption phases. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710001659 [article] Reallocation of adsorption and desorption times for optimisation of cooling cycles = Optimisation des cycles de refroidissement par modification des durées d'adsorption et de désorption [texte imprimé] / Yu.I. Aristov, Auteur ; A. Sapienza, Auteur ; D.S. Ovoshchnikov, Auteur . - 2012 . - pp. 525–531. Génie mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 525–531 Mots-clés : Adsorption  system  Variation  Duration  Cycle-adsorption  Desorption  Optimisation  COP  Water Résumé : In an adsorption cycle it is common to have an equal duration of the adsorption and desorption phases. In this paper, we investigated an intermittent cooling cycle with variable adsorption/desorption duration at fixed total cycle time. A new composite, LiNO3/silica KSK (SWS-9L), was used as a water sorbent. It was specifically synthesised for adsorptive chilling units driven by low temperature heat (65–75 °C). The sorption equilibrium and dynamics of SWS-9L were studied under conditions close to those realized in a typical cooling cycle. The actual performance of SWS-9L was tested in a single bed adsorption chiller with special emphasis on the optimisation of the relative duration of isobaric adsorption and desorption stages to maximize the Coefficient Of Performance and the Specific Cooling Power of the cycle. The tests resulted in being able to make practical recommendations to rationally optimise the relative duration of adsorption and desorption phases. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710001659

Performance analysis of a multi-mode thermochemical sorption refrigeration system for solar-powered cooling / T.X. Li in International journal of refrigeration, Vol. 35 N° 3 (Mai 2012) 

Public ISBD [article]  in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 532–542 Titre : Performance analysis of a multi-mode thermochemical sorption refrigeration system for solar-powered cooling Titre original : Analyse de la performance d’un système frigorifique thermochimique à sorption multimodal pour le refroidissement solaire Type de document : texte imprimé Auteurs : T.X. Li, Auteur ; R.Z. Wang, Auteur ; J.K. Kiplaga, Auteur Année de publication : 2012 Article en page(s) : pp. 532–542 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Solar  energy  Sorption  system  Refrigeration  Heat  recovery  Thermodynamic  cycle Résumé : A multi-mode thermochemical sorption refrigeration system is presented for solar-powered cooling. The proposed system consists of three sorption refrigeration thermodynamic cycles that can be alternately operated based on the available solar energy insolation viz: combined double-way cycle, double-effect cycle and two-stage cycle. The working performance of the different sorption refrigeration cycles were theoretically analyzed and compared. For combined double-way sorption cycle, both adsorption refrigeration and resorption refrigeration were combined to improve the cooling capacity. For double-effect sorption cycle, one internal heat recovery process was employed to enhance the energy utilization efficiency. For two-stage cycle with internal heat recovery process, a secondary reactive salt was used to lower the driving regeneration temperature. Thermodynamic analysis showed that the working modes of the proposed system can be switched according to the different driving heat source temperatures. In comparison with the conventional solar solid-gas sorption refrigeration system, the presented multi-mode system can contribute to improving the utilization efficiency of solar energy and widening the scope of application of solar thermochemical sorption refrigerator. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002738 [article] Performance analysis of a multi-mode thermochemical sorption refrigeration system for solar-powered cooling = Analyse de la performance d’un système frigorifique thermochimique à sorption multimodal pour le refroidissement solaire [texte imprimé] / T.X. Li, Auteur ; R.Z. Wang, Auteur ; J.K. Kiplaga, Auteur . - 2012 . - pp. 532–542. Génie mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 532–542 Mots-clés : Solar  energy  Sorption  system  Refrigeration  Heat  recovery  Thermodynamic  cycle Résumé : A multi-mode thermochemical sorption refrigeration system is presented for solar-powered cooling. The proposed system consists of three sorption refrigeration thermodynamic cycles that can be alternately operated based on the available solar energy insolation viz: combined double-way cycle, double-effect cycle and two-stage cycle. The working performance of the different sorption refrigeration cycles were theoretically analyzed and compared. For combined double-way sorption cycle, both adsorption refrigeration and resorption refrigeration were combined to improve the cooling capacity. For double-effect sorption cycle, one internal heat recovery process was employed to enhance the energy utilization efficiency. For two-stage cycle with internal heat recovery process, a secondary reactive salt was used to lower the driving regeneration temperature. Thermodynamic analysis showed that the working modes of the proposed system can be switched according to the different driving heat source temperatures. In comparison with the conventional solar solid-gas sorption refrigeration system, the presented multi-mode system can contribute to improving the utilization efficiency of solar energy and widening the scope of application of solar thermochemical sorption refrigerator. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002738

Evaluation of methanol adsorption on activated carbons for thermally driven chillers part I / S.K. Henninger in International journal of refrigeration, Vol. 35 N° 3 (Mai 2012) 

Public ISBD [article]  in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 543–553 Titre : Evaluation of methanol adsorption on activated carbons for thermally driven chillers part I : Thermophysical characterisation Titre original : Evaluation de l'adsorption de méthanol sur du charbon actif dans les refroidisseurs à entraînement thermique. Partie I: caractérisation thermophysique Type de document : texte imprimé Auteurs : S.K. Henninger, Auteur ; M. Schicktanz, Auteur ; P.P.C. Hügenell, Auteur Année de publication : 2012 Article en page(s) : pp. 543–553 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Activated  carbon  Methanol  Heat  pump  Adsorption  system  Refrigerating  unit  Thermodynamic  cycle Résumé : In this first part a comprehensive thermophysical characterisation of six activated carbons – based on coconut, peat and stone coal with focus on thermally driven chillers is reported. Pore and surface analysis are performed using N2 and CO2 adsorption. Furthermore the density and heat capacity of the samples is determined. Methanol adsorption measurements for evaporation between −5 °C and 35 °C and driving temperatures up to 130 °C are realized using a thermobalance and evaluated using the Dubinin–Astakhov (DA) approach. Based on the given DA equations, the possible loading lifts for typical applications like 95°-35°-7 °C are calculated. The samples show very attractive maximum loading lifts up to 0.385 g g−1. Furthermore the mass and volume specific cooling enthalpy of 244 kJ kg−1 and 126 kJ dm−3 under realistic conditions demonstrates the good performance of this working pair. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002489 [article] Evaluation of methanol adsorption on activated carbons for thermally driven chillers part I = Evaluation de l'adsorption de méthanol sur du charbon actif dans les refroidisseurs à entraînement thermique. Partie I: caractérisation thermophysique : Thermophysical characterisation [texte imprimé] / S.K. Henninger, Auteur ; M. Schicktanz, Auteur ; P.P.C. Hügenell, Auteur . - 2012 . - pp. 543–553. Génie mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 543–553 Mots-clés : Activated  carbon  Methanol  Heat  pump  Adsorption  system  Refrigerating  unit  Thermodynamic  cycle Résumé : In this first part a comprehensive thermophysical characterisation of six activated carbons – based on coconut, peat and stone coal with focus on thermally driven chillers is reported. Pore and surface analysis are performed using N2 and CO2 adsorption. Furthermore the density and heat capacity of the samples is determined. Methanol adsorption measurements for evaporation between −5 °C and 35 °C and driving temperatures up to 130 °C are realized using a thermobalance and evaluated using the Dubinin–Astakhov (DA) approach. Based on the given DA equations, the possible loading lifts for typical applications like 95°-35°-7 °C are calculated. The samples show very attractive maximum loading lifts up to 0.385 g g−1. Furthermore the mass and volume specific cooling enthalpy of 244 kJ kg−1 and 126 kJ dm−3 under realistic conditions demonstrates the good performance of this working pair. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002489

Evaluation of methanol/activated carbons for thermally driven chillers, part II / M. Schicktanz in International journal of refrigeration, Vol. 35 N° 3 (Mai 2012) 

Public ISBD [article]  in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 554–561 Titre : Evaluation of methanol/activated carbons for thermally driven chillers, part II : The energy balance model Titre original : Evaluation des couples actifs méthanol / charbon actif utilisés dans les refroidisseurs entraînés par la chaleur. Partie II: le modèle de bilan thermique Type de document : texte imprimé Auteurs : M. Schicktanz, Auteur ; P. Hügenell, Auteur ; S.K. Henninger, Auteur Année de publication : 2012 Article en page(s) : pp. 554–561 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Adsorption  Methanol  Activated  carbon  COP  Chilling  Energy  balance Résumé : This paper describes a simple energy balance model based on static parameters to calculate the COP of an adsorption chiller. The model leads to an analytical equation using basic information about the working pair, the chiller design and the operation temperatures. A set of dimensionless key figures is derived for better understanding of the influence of physical parameters on the COP. These key figures are investigated in this paper. In contrast to absorption chillers, desorption is not an isobaric process in adsorption chillers. The influence of the path is discussed in the limits of isobaric and isothermal desorption. Furthermore, the model is applied to a set of new material data, focussingfocussing on methanol/activated carbon as the working pair. This working pair makes refrigeration below 0°C feasible. This paper is the second of two articles about the measurement and evaluation of methanol/activated carbon for cooling purposes in adsorption chillers. The first part contains the experimental description and the thermophysical properties of methanol/activated carbon. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711000776 [article] Evaluation of methanol/activated carbons for thermally driven chillers, part II = Evaluation des couples actifs méthanol / charbon actif utilisés dans les refroidisseurs entraînés par la chaleur. Partie II: le modèle de bilan thermique : The energy balance model [texte imprimé] / M. Schicktanz, Auteur ; P. Hügenell, Auteur ; S.K. Henninger, Auteur . - 2012 . - pp. 554–561. Génie mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 554–561 Mots-clés : Adsorption  Methanol  Activated  carbon  COP  Chilling  Energy  balance Résumé : This paper describes a simple energy balance model based on static parameters to calculate the COP of an adsorption chiller. The model leads to an analytical equation using basic information about the working pair, the chiller design and the operation temperatures. A set of dimensionless key figures is derived for better understanding of the influence of physical parameters on the COP. These key figures are investigated in this paper. In contrast to absorption chillers, desorption is not an isobaric process in adsorption chillers. The influence of the path is discussed in the limits of isobaric and isothermal desorption. Furthermore, the model is applied to a set of new material data, focussingfocussing on methanol/activated carbon as the working pair. This working pair makes refrigeration below 0°C feasible. This paper is the second of two articles about the measurement and evaluation of methanol/activated carbon for cooling purposes in adsorption chillers. The first part contains the experimental description and the thermophysical properties of methanol/activated carbon. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711000776

COP trends for ideal thermal wave adsorption cooling cycles with enhancements / Onur Taylan in International journal of refrigeration, Vol. 35 N° 3 (Mai 2012) 

Public ISBD [article]  in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 562–570 Titre : COP trends for ideal thermal wave adsorption cooling cycles with enhancements Titre original : Cycles de refroidissement améliorés idéaux aux ondes thermiques à adsorption: tendances des COP Type de document : texte imprimé Auteurs : Onur Taylan, Auteur ; Derek K. Baker, Auteur ; Bilgin Kaftanoğlu, Auteur Année de publication : 2012 Article en page(s) : pp. 562–570 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Adsorption  system  Modelling  Simulation  Wave-heat  Mass  transfer Résumé : Models are presented for ideal thermal wave adsorption cooling cycles without mass recovery, with adiabatic mass recovery and with isothermal mass recovery. Coefficient of performance (COP) values obtained from simulations are compared with the results of a reversible cycle and previously developed models for a simple cycle and heat recovery cycle with two spatially isothermal beds (2SIB). The effects of maximum and minimum bed temperatures, bed’s dead mass, and condensation and evaporation temperatures on COP were investigated. The thermal wave cycle has significantly higher COP’s than the simple and 2SIB cycles. For the conditions investigated, adding mass recovery to the thermal wave cycle does not affect its COP significantly. The COP of the thermal wave cycle increases with increasing maximum bed and evaporation temperatures and decreasing minimum bed and condensation temperatures. Unlike for the simple and 2SIB cycles, variations in the bed’s dead mass have minimal impact on COP. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710001544 [article] COP trends for ideal thermal wave adsorption cooling cycles with enhancements = Cycles de refroidissement améliorés idéaux aux ondes thermiques à adsorption: tendances des COP [texte imprimé] / Onur Taylan, Auteur ; Derek K. Baker, Auteur ; Bilgin Kaftanoğlu, Auteur . - 2012 . - pp. 562–570. Génie mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 562–570 Mots-clés : Adsorption  system  Modelling  Simulation  Wave-heat  Mass  transfer Résumé : Models are presented for ideal thermal wave adsorption cooling cycles without mass recovery, with adiabatic mass recovery and with isothermal mass recovery. Coefficient of performance (COP) values obtained from simulations are compared with the results of a reversible cycle and previously developed models for a simple cycle and heat recovery cycle with two spatially isothermal beds (2SIB). The effects of maximum and minimum bed temperatures, bed’s dead mass, and condensation and evaporation temperatures on COP were investigated. The thermal wave cycle has significantly higher COP’s than the simple and 2SIB cycles. For the conditions investigated, adding mass recovery to the thermal wave cycle does not affect its COP significantly. The COP of the thermal wave cycle increases with increasing maximum bed and evaporation temperatures and decreasing minimum bed and condensation temperatures. Unlike for the simple and 2SIB cycles, variations in the bed’s dead mass have minimal impact on COP. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710001544

Optimal cycle selection in carbon-ammonia adsorption cycles / S.J. Metcalf in International journal of refrigeration, Vol. 35 N° 3 (Mai 2012) 

Public ISBD [article]  in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 571–580 Titre : Optimal cycle selection in carbon-ammonia adsorption cycles Titre original : Choix du cycle optimal parmi des cycles à adsorption au charbon actif / ammoniac Type de document : texte imprimé Auteurs : S.J. Metcalf, Auteur ; R.E. Critoph, Auteur ; Z. Tamainot-Telto, Auteur Année de publication : 2012 Article en page(s) : pp. 571–580 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Adsorption  Heat  pump  Ammonia  Activated  carbon  Modelling Résumé : Computational modelling of multiple-bed and thermal wave adsorption cycles is carried out in order to determine which method of heat recovery gives the superior trade off between coefficient of performance (COP) and power density (the power output per unit mass or volume of machine). The modelling is performed for the activated carbon-ammonia pair with a high power density plate heat exchanger type generator. It is discovered that multiple-bed cycles give a superior trade-off between COP and power density and are therefore recommended over thermal wave cycles. The principal application is considered to be a gas fired heat pump and it is found that the technology compares favourably with competing systems. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S014070071100274X [article] Optimal cycle selection in carbon-ammonia adsorption cycles = Choix du cycle optimal parmi des cycles à adsorption au charbon actif / ammoniac [texte imprimé] / S.J. Metcalf, Auteur ; R.E. Critoph, Auteur ; Z. Tamainot-Telto, Auteur . - 2012 . - pp. 571–580. Génie mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 571–580 Mots-clés : Adsorption  Heat  pump  Ammonia  Activated  carbon  Modelling Résumé : Computational modelling of multiple-bed and thermal wave adsorption cycles is carried out in order to determine which method of heat recovery gives the superior trade off between coefficient of performance (COP) and power density (the power output per unit mass or volume of machine). The modelling is performed for the activated carbon-ammonia pair with a high power density plate heat exchanger type generator. It is discovered that multiple-bed cycles give a superior trade-off between COP and power density and are therefore recommended over thermal wave cycles. The principal application is considered to be a gas fired heat pump and it is found that the technology compares favourably with competing systems. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S014070071100274X

Numerical simulation of heat and mass transfer in adsorbent beds with annular fins / Hamid Niazmand in International journal of refrigeration, Vol. 35 N° 3 (Mai 2012) 

Public ISBD [article]  in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 581–593 Titre : Numerical simulation of heat and mass transfer in adsorbent beds with annular fins Titre original : Simulation numérique du transfert de chaleur et de masse dans des lits absorbants munis d'ailettes annulaires Type de document : texte imprimé Auteurs : Hamid Niazmand, Auteur ; Iman Dabzadeh, Auteur Année de publication : 2012 Article en page(s) : pp. 581–593 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Adsorbent  System  Adsorption  Porous  medium  Mass  transfer  Heat  transfer  Desorption Résumé : A transient two-dimensional numerical model of combined heat and mass transfer in the adsorbent bed of a silica gel/water adsorption chiller is presented for a cylindrical bed with annular fins. The bed transient transport behaviors are discussed for all cycle phases. Complex flow patterns are found for isosteric heating and cooling phases due to the simultaneous occurrence of the adsorption and desorption processes. Furthermore, the effects of bed configurations such as fin spacing, bed height, and particle size on the performance of the system are examined. Results show that fins in general reduce the COP of the system; however, for a given total cooling power, the bed size can be reduced dramatically, when fins are employed at the cost of slightly lower COP. It is also shown that there is an optimum particle diameter associated with each bed configuration that maximizes the COP, TCP, and SCP of the system. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711001198 [article] Numerical simulation of heat and mass transfer in adsorbent beds with annular fins = Simulation numérique du transfert de chaleur et de masse dans des lits absorbants munis d'ailettes annulaires [texte imprimé] / Hamid Niazmand, Auteur ; Iman Dabzadeh, Auteur . - 2012 . - pp. 581–593. Génie mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 581–593 Mots-clés : Adsorbent  System  Adsorption  Porous  medium  Mass  transfer  Heat  transfer  Desorption Résumé : A transient two-dimensional numerical model of combined heat and mass transfer in the adsorbent bed of a silica gel/water adsorption chiller is presented for a cylindrical bed with annular fins. The bed transient transport behaviors are discussed for all cycle phases. Complex flow patterns are found for isosteric heating and cooling phases due to the simultaneous occurrence of the adsorption and desorption processes. Furthermore, the effects of bed configurations such as fin spacing, bed height, and particle size on the performance of the system are examined. Results show that fins in general reduce the COP of the system; however, for a given total cooling power, the bed size can be reduced dramatically, when fins are employed at the cost of slightly lower COP. It is also shown that there is an optimum particle diameter associated with each bed configuration that maximizes the COP, TCP, and SCP of the system. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711001198

Thermodynamic simulation of alternative absorption heat pumping processes using natural working fluids / O. Kotenko in International journal of refrigeration, Vol. 35 N° 3 (Mai 2012) 

Public ISBD [article]  in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 594–604 Titre : Thermodynamic simulation of alternative absorption heat pumping processes using natural working fluids Titre original : Simulation thermodynamique des procédés de remplacement à pompe à chaleur à absorption utilisant des frigorigènes naturels Type de document : texte imprimé Auteurs : O. Kotenko, Auteur ; H. Moser, Auteur ; R. Rieberer, Auteur Année de publication : 2012 Article en page(s) : pp. 594–604 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Absorption  Heat  pump  Heat  transformer  Process  analysis  Refrigeration  Simulation Résumé : Three groups of alternative absorption heat pumping processes (AHP) with different natural working fluids are being analyzed in this paper: Image Absorption heat transformer (AHT) process using partially miscible working mixtures; Image AHP-processes using a condensable auxiliary fluid (Einstein–Szilard cycle, Rojey cycle); Image NH3/H2O-AHP-process using strong bases as additives (e.g. NaOH). The thermodynamic simulations have shown that a NH3/H2O absorption cycle using a strong base as additive seems to be promising for applications using low-grade heat sources and the Rojey cycle offers higher COPs than a conventional NH3/H2O-AHP at high generator temperatures and low temperature lifts. The investigated AHT-process and the Einstein–Szilard process seem presently not to be competitive compared to conventional technologies. At present the influence of strong bases on a conventional NH3/H2O-AHP is being investigated at the Institute of Thermal Engineering, Graz University of Technology. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002490 [article] Thermodynamic simulation of alternative absorption heat pumping processes using natural working fluids = Simulation thermodynamique des procédés de remplacement à pompe à chaleur à absorption utilisant des frigorigènes naturels [texte imprimé] / O. Kotenko, Auteur ; H. Moser, Auteur ; R. Rieberer, Auteur . - 2012 . - pp. 594–604. Génie mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 594–604 Mots-clés : Absorption  Heat  pump  Heat  transformer  Process  analysis  Refrigeration  Simulation Résumé : Three groups of alternative absorption heat pumping processes (AHP) with different natural working fluids are being analyzed in this paper: Image Absorption heat transformer (AHT) process using partially miscible working mixtures; Image AHP-processes using a condensable auxiliary fluid (Einstein–Szilard cycle, Rojey cycle); Image NH3/H2O-AHP-process using strong bases as additives (e.g. NaOH). The thermodynamic simulations have shown that a NH3/H2O absorption cycle using a strong base as additive seems to be promising for applications using low-grade heat sources and the Rojey cycle offers higher COPs than a conventional NH3/H2O-AHP at high generator temperatures and low temperature lifts. The investigated AHT-process and the Einstein–Szilard process seem presently not to be competitive compared to conventional technologies. At present the influence of strong bases on a conventional NH3/H2O-AHP is being investigated at the Institute of Thermal Engineering, Graz University of Technology. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002490

An advanced analytical model of the Diffusion Absorption Refrigerator cycle / Giuseppe Starace in International journal of refrigeration, Vol. 35 N° 3 (Mai 2012) 

Public ISBD [article]  in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 605–612 Titre : An advanced analytical model of the Diffusion Absorption Refrigerator cycle Titre original : Modèle analytique de pointe du cycle frigorifique à absorption à diffusion Type de document : texte imprimé Auteurs : Giuseppe Starace, Auteur ; Lorenzo De Pascalis, Auteur Année de publication : 2012 Article en page(s) : pp. 605–612 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Adsorption  Diffusion  absorption  refrigerator  Diffusion  system  Analytical  model  Refrigeration  cycle Résumé : The results about the performance of a new DAR’s thermodynamic model are compared with the predictions of Zohar et al. (2009). The main difference is due to an accurate modeling of the refrigerant composition, assumed there as pure ammonia. A sensitivity analysis shows that, as the generator temperature increases, the rich solution mass flowrate reduces more than that of the refrigerant one, and COP decreases. This happens as the absorption temperature increases as well, due to the lower absorption of ammonia in the weak solution. COP was found to increase when the ammonia concentration decreases. In addition, for lower heat fluxes supplied to the generator, the heat dissipation toward ambient dominates and COP becomes small; when the heat flux overtakes a threshold, the evaporator reaches its maximum heat transfer, that remains constant for any further increase of heat supplied. COP presents its highest values over a limited range of the generator’s operating conditions. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002751 [article] An advanced analytical model of the Diffusion Absorption Refrigerator cycle = Modèle analytique de pointe du cycle frigorifique à absorption à diffusion [texte imprimé] / Giuseppe Starace, Auteur ; Lorenzo De Pascalis, Auteur . - 2012 . - pp. 605–612. Génie mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 605–612 Mots-clés : Adsorption  Diffusion  absorption  refrigerator  Diffusion  system  Analytical  model  Refrigeration  cycle Résumé : The results about the performance of a new DAR’s thermodynamic model are compared with the predictions of Zohar et al. (2009). The main difference is due to an accurate modeling of the refrigerant composition, assumed there as pure ammonia. A sensitivity analysis shows that, as the generator temperature increases, the rich solution mass flowrate reduces more than that of the refrigerant one, and COP decreases. This happens as the absorption temperature increases as well, due to the lower absorption of ammonia in the weak solution. COP was found to increase when the ammonia concentration decreases. In addition, for lower heat fluxes supplied to the generator, the heat dissipation toward ambient dominates and COP becomes small; when the heat flux overtakes a threshold, the evaporator reaches its maximum heat transfer, that remains constant for any further increase of heat supplied. COP presents its highest values over a limited range of the generator’s operating conditions. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002751

Measurement of absorption rates in horizontal-tube falling-film ammonia-water absorbers / Sangsoo Lee in International journal of refrigeration, Vol. 35 N° 3 (Mai 2012) 

Public ISBD [article]  in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 613–632 Titre : Measurement of absorption rates in horizontal-tube falling-film ammonia-water absorbers Titre original : Mesures des taux d'absorption des absorbeurs à ammoniac / eau aux tubes horizontaux à film tombant Type de document : texte imprimé Auteurs : Sangsoo Lee, Auteur ; Lalit Kumar Bohra, Auteur ; Srinivas Garimella, Auteur Année de publication : 2012 Article en page(s) : pp. 613–632 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Absorption  Falling  film  Heat  transfer  Mass  transfer  Ammonia  Water Résumé : Heat and mass transfer in a horizontal-tube falling-film ammonia-water absorber was investigated. A tube bank consisting of four columns of six 9.5 mm nominal OD, 0.292 m long tubes was installed in a shell that allowed heat and mass transfer measurements and optical access for flow visualization. This absorber was installed in a test facility consisting of all the components of a chiller, fabricated to obtain realistic operating conditions at the absorber to account for the influence of the other components in the system. Tests were conducted over desorber solution outlet concentrations of 5–40% for three nominal absorber pressures of 150, 345 and 500 kPa, for solution flow rates of 0.019–0.034 kg s−1. Measurement and analysis techniques, heat transfer rates, and solution- and vapor-side heat and mass transfer coefficients are described. Trends in heat and mass transfer coefficients are discussed, highlighting the effects of solution flow rate and concentration, and absorber pressure. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002131 [article] Measurement of absorption rates in horizontal-tube falling-film ammonia-water absorbers = Mesures des taux d'absorption des absorbeurs à ammoniac / eau aux tubes horizontaux à film tombant [texte imprimé] / Sangsoo Lee, Auteur ; Lalit Kumar Bohra, Auteur ; Srinivas Garimella, Auteur . - 2012 . - pp. 613–632. Génie mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 613–632 Mots-clés : Absorption  Falling  film  Heat  transfer  Mass  transfer  Ammonia  Water Résumé : Heat and mass transfer in a horizontal-tube falling-film ammonia-water absorber was investigated. A tube bank consisting of four columns of six 9.5 mm nominal OD, 0.292 m long tubes was installed in a shell that allowed heat and mass transfer measurements and optical access for flow visualization. This absorber was installed in a test facility consisting of all the components of a chiller, fabricated to obtain realistic operating conditions at the absorber to account for the influence of the other components in the system. Tests were conducted over desorber solution outlet concentrations of 5–40% for three nominal absorber pressures of 150, 345 and 500 kPa, for solution flow rates of 0.019–0.034 kg s−1. Measurement and analysis techniques, heat transfer rates, and solution- and vapor-side heat and mass transfer coefficients are described. Trends in heat and mass transfer coefficients are discussed, highlighting the effects of solution flow rate and concentration, and absorber pressure. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002131

Assessment of boiling heat transfer and pressure drop correlations of ammonia/water mixture in a plate heat exchanger / Francisco Táboas in International journal of refrigeration, Vol. 35 N° 3 (Mai 2012) 

Public ISBD [article]  in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 633–644 Titre : Assessment of boiling heat transfer and pressure drop correlations of ammonia/water mixture in a plate heat exchanger Titre original : Evaluation des corrélations entre le transfert de chaleur lors de l'ébullition et la chute de pression d'un mélange ammoniac / eau dans un échangeur à plaques Type de document : texte imprimé Auteurs : Francisco Táboas, Auteur ; Manel Vallès, Auteur ; Bourouis, Mahmoud, Auteur Année de publication : 2012 Article en page(s) : pp. 633–644 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Absorption  cycle  Boiling  Heat  transfer  Plate  exchanger  Pressure  drop  Ammonia–water Résumé : Plate heat exchangers are gaining acceptance in absorption refrigeration systems due to their high transfer rates, compactness, and low refrigerant charge. Nevertheless, boiling heat transfer and pressure drop studies with mixtures in plate heat exchangers (PHEs) are scarce. In this study, the experimental data of Táboas et al. (2010) on flow boiling of ammonia/water in a plate heat exchanger are compared with the predicted values using the correlations available in the open literature for the boiling heat transfer coefficient and pressure drop. In addition, this study proposes a new correlation based on a separate model by which to obtain the boiling coefficient. The new correlation uses a transition criterion, divided into an apparent nucleate boiling region where pure convective boiling cannot appear, and a region with competition between convective and apparent nucleate boiling. The correlation proposed can predict 98% of data from Táboas et al. (2010) within 20% error. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002477 [article] Assessment of boiling heat transfer and pressure drop correlations of ammonia/water mixture in a plate heat exchanger = Evaluation des corrélations entre le transfert de chaleur lors de l'ébullition et la chute de pression d'un mélange ammoniac / eau dans un échangeur à plaques [texte imprimé] / Francisco Táboas, Auteur ; Manel Vallès, Auteur ; Bourouis, Mahmoud, Auteur . - 2012 . - pp. 633–644. Génie mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 633–644 Mots-clés : Absorption  cycle  Boiling  Heat  transfer  Plate  exchanger  Pressure  drop  Ammonia–water Résumé : Plate heat exchangers are gaining acceptance in absorption refrigeration systems due to their high transfer rates, compactness, and low refrigerant charge. Nevertheless, boiling heat transfer and pressure drop studies with mixtures in plate heat exchangers (PHEs) are scarce. In this study, the experimental data of Táboas et al. (2010) on flow boiling of ammonia/water in a plate heat exchanger are compared with the predicted values using the correlations available in the open literature for the boiling heat transfer coefficient and pressure drop. In addition, this study proposes a new correlation based on a separate model by which to obtain the boiling coefficient. The new correlation uses a transition criterion, divided into an apparent nucleate boiling region where pure convective boiling cannot appear, and a region with competition between convective and apparent nucleate boiling. The correlation proposed can predict 98% of data from Táboas et al. (2010) within 20% error. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002477

Heat and mass transfer enhancement for falling film absorption process by SiO2 binary nanofluids / Hyundae Kim in International journal of refrigeration, Vol. 35 N° 3 (Mai 2012) 

Public ISBD [article]  in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 645–651 Titre : Heat and mass transfer enhancement for falling film absorption process by SiO2 binary nanofluids Titre original : Amélioration du transfert de chaleur et de masse lors du processus d'absorption sur un film tombant faisant appel aux nanofluides binaires au SiO2 Type de document : texte imprimé Auteurs : Hyundae Kim, Auteur ; Jinhee Jeong, Auteur ; Yong Tae Kang, Auteur Année de publication : 2012 Article en page(s) : pp. 645–651 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Water–lithium  bromide  Distribution  Stability  Absorption  system  Enhancement Résumé : The objectives of this study are to visualize the dispersion of nano-particles in binary nanofluids, to find the effect of key parameters such as SiO2 nano-particles concentration on the distribution stability in the H2O/LiBr nanofluids, and to measure the vapor absorption rate and heat transfer rate for falling film flow of binary nanofluids. The binary nanofluids are H2O/LiBr with SiO2 nano-particle. The key parameters are the base fluid concentration of LiBr, the concentration of SiO2 nano-particles in vol%, and kinds of additives. It is found that the concentration of SiO2 nano-particles should be less than 0.01 regardless of the existence of the distribution stabilizer. It is also found that the maximum improvements of heat transfer rate and mass transfer rate reach 46.8% and 18%, respectively, when the concentration of SiO2 nano-particle is 0.005 vol%. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002982 [article] Heat and mass transfer enhancement for falling film absorption process by SiO2 binary nanofluids = Amélioration du transfert de chaleur et de masse lors du processus d'absorption sur un film tombant faisant appel aux nanofluides binaires au SiO2 [texte imprimé] / Hyundae Kim, Auteur ; Jinhee Jeong, Auteur ; Yong Tae Kang, Auteur . - 2012 . - pp. 645–651. Génie mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 645–651 Mots-clés : Water–lithium  bromide  Distribution  Stability  Absorption  system  Enhancement Résumé : The objectives of this study are to visualize the dispersion of nano-particles in binary nanofluids, to find the effect of key parameters such as SiO2 nano-particles concentration on the distribution stability in the H2O/LiBr nanofluids, and to measure the vapor absorption rate and heat transfer rate for falling film flow of binary nanofluids. The binary nanofluids are H2O/LiBr with SiO2 nano-particle. The key parameters are the base fluid concentration of LiBr, the concentration of SiO2 nano-particles in vol%, and kinds of additives. It is found that the concentration of SiO2 nano-particles should be less than 0.01 regardless of the existence of the distribution stabilizer. It is also found that the maximum improvements of heat transfer rate and mass transfer rate reach 46.8% and 18%, respectively, when the concentration of SiO2 nano-particle is 0.005 vol%. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002982

Numerical investigation of coupled heat and mass transfer inside the adsorbent bed of an adsorption cooling unit / İsmail Solmuş in International journal of refrigeration, Vol. 35 N° 3 (Mai 2012) 

Public ISBD [article]  in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 652–662 Titre : Numerical investigation of coupled heat and mass transfer inside the adsorbent bed of an adsorption cooling unit Titre original : Etude numérique sur le transfert de chaleur et de masse à l’intérieur du lit absorbant d’un système de refroidissement à adsorption Type de document : texte imprimé Auteurs : İsmail Solmuş, Auteur ; D. Andrew S. Rees, Auteur ; Cemil Yamalı, Auteur Année de publication : 2012 Article en page(s) : pp. 652–662 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Adsorption  Adsorbent  Cooling  Silica  gel Résumé : In this study, the influence of several design parameters on the transient distributions of temperature, pressure and amount adsorbed in the radial direction of a cylindrical adsorbent bed of an adsorption cooling unit using silica gel/water have been investigated numerically. For this purpose, a transient one-dimensional local thermal non-equilibrium model that accounts for both internal and external mass transfer resistances has been developed using the local volume averaging method. For the conditions investigated, the validity of the local thermal equilibrium and spatially isobaric bed assumptions have been confirmed. To improve the performance of the bed considered, efforts should be focused on reducing heat transfer resistances and intra-particle (interior) mass transfer resistances but not inter-particle (exterior) mass transfer resistances. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711003070# [article] Numerical investigation of coupled heat and mass transfer inside the adsorbent bed of an adsorption cooling unit = Etude numérique sur le transfert de chaleur et de masse à l’intérieur du lit absorbant d’un système de refroidissement à adsorption [texte imprimé] / İsmail Solmuş, Auteur ; D. Andrew S. Rees, Auteur ; Cemil Yamalı, Auteur . - 2012 . - pp. 652–662. Génie mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 652–662 Mots-clés : Adsorption  Adsorbent  Cooling  Silica  gel Résumé : In this study, the influence of several design parameters on the transient distributions of temperature, pressure and amount adsorbed in the radial direction of a cylindrical adsorbent bed of an adsorption cooling unit using silica gel/water have been investigated numerically. For this purpose, a transient one-dimensional local thermal non-equilibrium model that accounts for both internal and external mass transfer resistances has been developed using the local volume averaging method. For the conditions investigated, the validity of the local thermal equilibrium and spatially isobaric bed assumptions have been confirmed. To improve the performance of the bed considered, efforts should be focused on reducing heat transfer resistances and intra-particle (interior) mass transfer resistances but not inter-particle (exterior) mass transfer resistances. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711003070#

Performance studies on the desiccant packed bed with varying particle size distribution along the bed / A. K. Ramzy in International journal of refrigeration, Vol. 35 N° 3 (Mai 2012) 

Public ISBD [article]  in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 663–675 Titre : Performance studies on the desiccant packed bed with varying particle size distribution along the bed Titre original : Etudes sur la performance d'un matelas dispersant avec une distribution de la taille des particules différente selon les emplacements Type de document : texte imprimé Auteurs : A. K. Ramzy, Auteur ; Ravikiran Kadoli, Auteur ; T.P. Ashok Babu, Auteur Année de publication : 2012 Article en page(s) : pp. 663–675 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Optimization  Adsorbent  Adsorption  Desorption  Desiccant  Silica  gel Résumé : The transient heat and mass transfer in a desiccant packed bed containing varying particle diameter distribution along the axial direction has been investigated using the pseudo gas controlled approach that considers the heat conduction in the bed. The numerical results of the present model and the experimental data from literature show good agreement with a maximum root of mean square of errors of 3% and 2% for exit air temperature and humidity ratio, respectively. The improvement in the total mass adsorbed and/or reduction in pressure drop has been investigated for various cases of packed bed namely, uniform particle diameter, linear, parabolic and cubic ascending and descending distributions. It has been found that there is a 25.7% reduction in pressure drop with negligible reduction in the total mass adsorbed for a desiccant bed with cubic type particle size distribution when compared to the bed with uniform particle diameter of 1.0 mm. A threshold flow velocity exists below which the total mass adsorbed is independent of particle diameter distribution type. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002969 [article] Performance studies on the desiccant packed bed with varying particle size distribution along the bed = Etudes sur la performance d'un matelas dispersant avec une distribution de la taille des particules différente selon les emplacements [texte imprimé] / A. K. Ramzy, Auteur ; Ravikiran Kadoli, Auteur ; T.P. Ashok Babu, Auteur . - 2012 . - pp. 663–675. Génie mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 663–675 Mots-clés : Optimization  Adsorbent  Adsorption  Desorption  Desiccant  Silica  gel Résumé : The transient heat and mass transfer in a desiccant packed bed containing varying particle diameter distribution along the axial direction has been investigated using the pseudo gas controlled approach that considers the heat conduction in the bed. The numerical results of the present model and the experimental data from literature show good agreement with a maximum root of mean square of errors of 3% and 2% for exit air temperature and humidity ratio, respectively. The improvement in the total mass adsorbed and/or reduction in pressure drop has been investigated for various cases of packed bed namely, uniform particle diameter, linear, parabolic and cubic ascending and descending distributions. It has been found that there is a 25.7% reduction in pressure drop with negligible reduction in the total mass adsorbed for a desiccant bed with cubic type particle size distribution when compared to the bed with uniform particle diameter of 1.0 mm. A threshold flow velocity exists below which the total mass adsorbed is independent of particle diameter distribution type. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002969

Investigation of an improved solar-powered open absorption system for cooling, dehumidification and air conditioning / Khaled Gommed in International journal of refrigeration, Vol. 35 N° 3 (Mai 2012) 

Public ISBD [article]  in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 676–684 Titre : Investigation of an improved solar-powered open absorption system for cooling, dehumidification and air conditioning Titre original : Etude sur un système ouvert amélioré à absorption fonctionnant à l'énergie solaire utilisé pour le refroidissement, la déshumidification et le conditionnement d'air Type de document : texte imprimé Auteurs : Khaled Gommed, Auteur ; Gershon Grossman, Auteur Année de publication : 2012 Article en page(s) : pp. 676–684 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Liquid  desiccant  Air  conditioning  Dehumidification  Open  system  Absorption Résumé : This study is concerned with an open absorption (liquid desiccant) system, capable of producing both cooling and dehumidification for air conditioning, utilizing low-grade heat. The system includes a novel solution heat and mass exchanger (HME) designed to serve as a desiccant solution reservoir for both the absorber and desorber, enabling mass transfer between them with minimum heat transfer losses and eliminating the need for an external recuperative heat exchanger. The use of this new HME together with an improved solution flow arrangement in the new system facilitates the use of adiabatic absorption/desorption with minimum circulation heat losses and wetting problems. The characteristic performance of the system was studied under varying operating conditions. The use of the new HME has fulfilled the objective of reducing the time constant of the system, helped correct idling and level control problems and ensures maximum solution concentration on the absorber side during desorber operation. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002313 [article] Investigation of an improved solar-powered open absorption system for cooling, dehumidification and air conditioning = Etude sur un système ouvert amélioré à absorption fonctionnant à l'énergie solaire utilisé pour le refroidissement, la déshumidification et le conditionnement d'air [texte imprimé] / Khaled Gommed, Auteur ; Gershon Grossman, Auteur . - 2012 . - pp. 676–684. Génie mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 676–684 Mots-clés : Liquid  desiccant  Air  conditioning  Dehumidification  Open  system  Absorption Résumé : This study is concerned with an open absorption (liquid desiccant) system, capable of producing both cooling and dehumidification for air conditioning, utilizing low-grade heat. The system includes a novel solution heat and mass exchanger (HME) designed to serve as a desiccant solution reservoir for both the absorber and desorber, enabling mass transfer between them with minimum heat transfer losses and eliminating the need for an external recuperative heat exchanger. The use of this new HME together with an improved solution flow arrangement in the new system facilitates the use of adiabatic absorption/desorption with minimum circulation heat losses and wetting problems. The characteristic performance of the system was studied under varying operating conditions. The use of the new HME has fulfilled the objective of reducing the time constant of the system, helped correct idling and level control problems and ensures maximum solution concentration on the absorber side during desorber operation. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002313

Study on a waste heat-driven adsorption cooling cum desalination cycle / Kim Choon Ng in International journal of refrigeration, Vol. 35 N° 3 (Mai 2012) 

Public ISBD [article]  in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 685–693 Titre : Study on a waste heat-driven adsorption cooling cum desalination cycle Titre original : Etude sur un cycle de refroidissement à adsorption utilisé également pour le dessalement, entraîné à l'aide de la récupération de chaleur Type de document : texte imprimé Auteurs : Kim Choon Ng, Auteur ; Kyaw Thu, Auteur ; Bidyut Baran Saha, Auteur Année de publication : 2012 Article en page(s) : pp. 685–693 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Adsorption  Cooling  Desalination  Waste  heat  Recovery Résumé : This article presents the performance analysis of a waste heat-driven adsorption cycle. With the implementation of adsorption–desorption phenomena, the cycle simultaneously produces cooling energy and high-grade potable water. A mathematical model is developed using isotherm characteristics of the adsorbent/adsorbate pair (silica gel and water), energy and mass balances for the each component of the cycle. The cycle is analyzed using key performance parameters namely (i) specific cooling power (SCP), (ii) specific daily water production (SDWP), (iii) the coefficient of performance (COP) and (iv) the overall conversion ratio (OCR). The numerical results of the adsorption cycle are validated using experimental data. The parametric analysis using different hot and chilled water temperatures are reported. At 85 °C hot water inlet temperature, the cycle generates 3.6 m3 of potable water and 23 Rton of cooling at the produced chilled water temperature of 10 °C. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711000211 [article] Study on a waste heat-driven adsorption cooling cum desalination cycle = Etude sur un cycle de refroidissement à adsorption utilisé également pour le dessalement, entraîné à l'aide de la récupération de chaleur [texte imprimé] / Kim Choon Ng, Auteur ; Kyaw Thu, Auteur ; Bidyut Baran Saha, Auteur . - 2012 . - pp. 685–693. Génie mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 685–693 Mots-clés : Adsorption  Cooling  Desalination  Waste  heat  Recovery Résumé : This article presents the performance analysis of a waste heat-driven adsorption cycle. With the implementation of adsorption–desorption phenomena, the cycle simultaneously produces cooling energy and high-grade potable water. A mathematical model is developed using isotherm characteristics of the adsorbent/adsorbate pair (silica gel and water), energy and mass balances for the each component of the cycle. The cycle is analyzed using key performance parameters namely (i) specific cooling power (SCP), (ii) specific daily water production (SDWP), (iii) the coefficient of performance (COP) and (iv) the overall conversion ratio (OCR). The numerical results of the adsorption cycle are validated using experimental data. The parametric analysis using different hot and chilled water temperatures are reported. At 85 °C hot water inlet temperature, the cycle generates 3.6 m3 of potable water and 23 Rton of cooling at the produced chilled water temperature of 10 °C. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711000211

Experimental investigation on a fluidized-bed adsorber/desorber for the adsorption refrigeration system / Q. Wang in International journal of refrigeration, Vol. 35 N° 3 (Mai 2012) 

Public ISBD [article]  in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 694–700 Titre : Experimental investigation on a fluidized-bed adsorber/desorber for the adsorption refrigeration system Titre original : Etude expérimentale sur un adsorbeur / désorbeur à lit fluidisé pour un système frigorifique à adsorption Type de document : texte imprimé Auteurs : Q. Wang, Auteur ; X. Gao, Auteur ; J.Y. Xu, Auteur Année de publication : 2012 Article en page(s) : pp. 694–700 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Adsorption  Refrigeration  Experiment  Fluidization  Refrigerant  Specific  cooling  power Résumé : This paper proposed and designed a fluidized-bed adsorber/desorber which can be used in the adsorption refrigeration system in place of the conventional fixed-bed one. An experimental setup was built to investigate the performance of the fluidized-bed absorber/desorber and compare with that of the fixed-bed one using the working pair of activated carbon and R134a. The experimental results with 2 kg activated carbon show that the heat and mass transfer can be greatly enhanced either in adsorption or desorption in the proposed fluidized-bed adsorber/desorber The experimental results with 3 kg activated carbon show the similar enhancement, but the enhancement with 4 kg activated carbon was weakened either in adsorption or desorption due to the incomplete fluidization of the activated carbon. By way of the new approach, the poor heat and mass transfer in the conventional fixed-bed absorber/desorber can be overcome and the SCP of the adsorption refrigerator can be expected to be greatly improved accordingly. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711001393 [article] Experimental investigation on a fluidized-bed adsorber/desorber for the adsorption refrigeration system = Etude expérimentale sur un adsorbeur / désorbeur à lit fluidisé pour un système frigorifique à adsorption [texte imprimé] / Q. Wang, Auteur ; X. Gao, Auteur ; J.Y. Xu, Auteur . - 2012 . - pp. 694–700. Génie mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 694–700 Mots-clés : Adsorption  Refrigeration  Experiment  Fluidization  Refrigerant  Specific  cooling  power Résumé : This paper proposed and designed a fluidized-bed adsorber/desorber which can be used in the adsorption refrigeration system in place of the conventional fixed-bed one. An experimental setup was built to investigate the performance of the fluidized-bed absorber/desorber and compare with that of the fixed-bed one using the working pair of activated carbon and R134a. The experimental results with 2 kg activated carbon show that the heat and mass transfer can be greatly enhanced either in adsorption or desorption in the proposed fluidized-bed adsorber/desorber The experimental results with 3 kg activated carbon show the similar enhancement, but the enhancement with 4 kg activated carbon was weakened either in adsorption or desorption due to the incomplete fluidization of the activated carbon. By way of the new approach, the poor heat and mass transfer in the conventional fixed-bed absorber/desorber can be overcome and the SCP of the adsorption refrigerator can be expected to be greatly improved accordingly. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711001393

Development and lab-test of a mobile adsorption air-conditioner / Salvatore Vasta in International journal of refrigeration, Vol. 35 N° 3 (Mai 2012) 

Public ISBD [article]  in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 701–708 Titre : Development and lab-test of a mobile adsorption air-conditioner Titre original : Conditionneur d'air mobile à adsorption: Développement et essais en laboratoire Type de document : texte imprimé Auteurs : Salvatore Vasta, Auteur ; Angelo Freni, Auteur ; Alessio Sapienza, Auteur Année de publication : 2012 Article en page(s) : pp. 701–708 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Adsorption  Air  conditioning  Zeolite  Water Résumé : This paper is focused on the description of a mobile adsorption chiller for cooling in a truck cabin and its experimental performance. The prototype, designed and built at CNR – ITAE, consists of a double-bed adsorber connected with an evaporator and a condenser and driven by the low grade thermal energy coming from the engine coolant loop. Overall volume and weight of the machine are 170 dm3 and 60 kg, respectively. Performance assessment was preliminarily carried out at ITAE laboratory under the typical EU car air conditioning conditions. The experimental results obtained showed that the system is able to deliver an Average Cooling Power ACP = 1–2.3 kW and a Cooling COP = 0.25–0.45, at a desorption temperature of about 90 °C (Tev ∼ 8–14 °C and Tcon ∼ 28–35 °C). Afterwards, the cooling system was integrated in a real truck cabin (IVECO STRALIS) and tested on a laboratory test bench, where the engine cooling loop was simulated through an ideal heat source, so demonstrating that the chiller is able to provide cooling comfort to the passengers. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711000764 [article] Development and lab-test of a mobile adsorption air-conditioner = Conditionneur d'air mobile à adsorption: Développement et essais en laboratoire [texte imprimé] / Salvatore Vasta, Auteur ; Angelo Freni, Auteur ; Alessio Sapienza, Auteur . - 2012 . - pp. 701–708. Génie mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 701–708 Mots-clés : Adsorption  Air  conditioning  Zeolite  Water Résumé : This paper is focused on the description of a mobile adsorption chiller for cooling in a truck cabin and its experimental performance. The prototype, designed and built at CNR – ITAE, consists of a double-bed adsorber connected with an evaporator and a condenser and driven by the low grade thermal energy coming from the engine coolant loop. Overall volume and weight of the machine are 170 dm3 and 60 kg, respectively. Performance assessment was preliminarily carried out at ITAE laboratory under the typical EU car air conditioning conditions. The experimental results obtained showed that the system is able to deliver an Average Cooling Power ACP = 1–2.3 kW and a Cooling COP = 0.25–0.45, at a desorption temperature of about 90 °C (Tev ∼ 8–14 °C and Tcon ∼ 28–35 °C). Afterwards, the cooling system was integrated in a real truck cabin (IVECO STRALIS) and tested on a laboratory test bench, where the engine cooling loop was simulated through an ideal heat source, so demonstrating that the chiller is able to provide cooling comfort to the passengers. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711000764

Extension of the characteristic equation to absorption chillers with adiabatic absorbers / G. Gutiérrez-Urueta in International journal of refrigeration, Vol. 35 N° 3 (Mai 2012) 

Public ISBD [article]  in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 709–718 Titre : Extension of the characteristic equation to absorption chillers with adiabatic absorbers Titre original : Extension d'une équation caractéristique aux refroidisseurs à absorption munis d'absorbeurs adiabatiques Type de document : texte imprimé Auteurs : G. Gutiérrez-Urueta, Auteur ; P. Rodríguez, Auteur ; F. Ziegler, Auteur Année de publication : 2012 Article en page(s) : pp. 709–718 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Absorption  Lithium  bromide  Temperature  difference  Chilled  water  Air  conditioning Résumé : Various researchers have developed models of conventional H2O–LiBr absorption machines with the aim of predicting their performance. In this paper, the methodology of characteristic equations developed by Hellmann et al. (1998) is applied. This model is able to represent the capacity of single effect absorption chillers and heat pumps by means of simple algebraic equations. An extended characteristic equation based on a characteristic temperature difference has been obtained, considering the facility features. As a result, it is concluded that for adiabatic absorbers a subcooling temperature must be specified. The effect of evaporator overflow has been characterized. Its influence on cooling capacity has been included in the extended characteristic equation. Taking into account the particular design and operation features, a good agreement between experimental performance data and those obtained through the extended characteristic equation has been achieved at off-design operation. This allows its use for simulation and control purposes. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002556# [article] Extension of the characteristic equation to absorption chillers with adiabatic absorbers = Extension d'une équation caractéristique aux refroidisseurs à absorption munis d'absorbeurs adiabatiques [texte imprimé] / G. Gutiérrez-Urueta, Auteur ; P. Rodríguez, Auteur ; F. Ziegler, Auteur . - 2012 . - pp. 709–718. Génie mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 709–718 Mots-clés : Absorption  Lithium  bromide  Temperature  difference  Chilled  water  Air  conditioning Résumé : Various researchers have developed models of conventional H2O–LiBr absorption machines with the aim of predicting their performance. In this paper, the methodology of characteristic equations developed by Hellmann et al. (1998) is applied. This model is able to represent the capacity of single effect absorption chillers and heat pumps by means of simple algebraic equations. An extended characteristic equation based on a characteristic temperature difference has been obtained, considering the facility features. As a result, it is concluded that for adiabatic absorbers a subcooling temperature must be specified. The effect of evaporator overflow has been characterized. Its influence on cooling capacity has been included in the extended characteristic equation. Taking into account the particular design and operation features, a good agreement between experimental performance data and those obtained through the extended characteristic equation has been achieved at off-design operation. This allows its use for simulation and control purposes. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711002556#

Performance analysis of a novel control system for solar collectors coupled with sorption chillers / S. Saulich in International journal of refrigeration, Vol. 35 N° 3 (Mai 2012) 

Public ISBD [article]  in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 719–728 Titre : Performance analysis of a novel control system for solar collectors coupled with sorption chillers Titre original : Analyse de la performance d’un nouveau système de régulation des capteurs solaires couplés aux refroidisseurs à sorption Type de document : texte imprimé Auteurs : S. Saulich, Auteur ; U. Jakob, Auteur ; M.J. Cook, Auteur Année de publication : 2012 Article en page(s) : pp. 719–728 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Renewable  energy  Solar  collector  Sorption  system  Design  Efficiency  COP Résumé : This paper presents work on a holistic approach for improving the overall design of solar cooling systems. Newly developed methods for hydraulics and control were used to redesign an existing pilot plant. Measurements taken from the newly developed system show that target temperature control leads to an 81% increase of the Solar Cooling Efficiency (SCE) factor compared to the original pilot system. In addition to the improvements in system design, new efficiency factors for benchmarking solar cooling systems are presented. The Solar Supply Efficiency (SSE) factor provides a means of quantifying the quality of solar thermal charging systems relative to the usable heat to drive the sorption process. The product of the SSE with the already established COP of the chiller, leads to the SCE factor which, for the first time, provides a clear and concise benchmarking method for the overall design of solar cooling systems. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712000072 [article] Performance analysis of a novel control system for solar collectors coupled with sorption chillers = Analyse de la performance d’un nouveau système de régulation des capteurs solaires couplés aux refroidisseurs à sorption [texte imprimé] / S. Saulich, Auteur ; U. Jakob, Auteur ; M.J. Cook, Auteur . - 2012 . - pp. 719–728. Génie mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 719–728 Mots-clés : Renewable  energy  Solar  collector  Sorption  system  Design  Efficiency  COP Résumé : This paper presents work on a holistic approach for improving the overall design of solar cooling systems. Newly developed methods for hydraulics and control were used to redesign an existing pilot plant. Measurements taken from the newly developed system show that target temperature control leads to an 81% increase of the Solar Cooling Efficiency (SCE) factor compared to the original pilot system. In addition to the improvements in system design, new efficiency factors for benchmarking solar cooling systems are presented. The Solar Supply Efficiency (SSE) factor provides a means of quantifying the quality of solar thermal charging systems relative to the usable heat to drive the sorption process. The product of the SSE with the already established COP of the chiller, leads to the SCE factor which, for the first time, provides a clear and concise benchmarking method for the overall design of solar cooling systems. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712000072

Heat rejection and primary energy efficiency of solar driven absorption cooling systems / Ursula Eicker in International journal of refrigeration, Vol. 35 N° 3 (Mai 2012) 

Public ISBD [article]  in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 729–738 Titre : Heat rejection and primary energy efficiency of solar driven absorption cooling systems Titre original : Rejet de chaleur et efficacité de l'énergie primaire des systèmes de refroidissement à absorption faisant appel à l'énergie solaire Type de document : texte imprimé Auteurs : Ursula Eicker, Auteur ; Dirk Pietruschka, Auteur ; Ruben Pesch, Auteur Année de publication : 2012 Article en page(s) : pp. 729–738 Note générale : Génie mécanique Langues : Anglais (eng) Mots-clés : Primary  energy  Absorption  system  Control  Cooling  tower Résumé : Efficient heat rejection is crucial for the overall primary energy balance of sorption systems, as it dominates the auxiliary energy consumption. Low ratios of cooling power to auxiliary electricity of 3.0 or less are still common in sorption system, so that the primary energy efficiency is not always higher than for conventional compression chillers. Whereas dry heat rejection systems require electricity for fan operation, hybrid or wet cooling systems in addition need pumping energy for the cooling water and the water itself. The energy efficiency can be improved for heat rejection to the ground, where only pumping energy is needed for the geothermal heat exchange. Dynamic simulation models were used for a single effect absorption chiller powered by solar thermal collectors via a hot storage tank. The chiller models were coupled to a three dimensional numerical ground heat exchanger model or to cooling tower models. The models were validated with operating data of a 15 kW solar cooling system installed in an office building. Primary energy efficiency ratios were determined for different heat rejection systems and improved control strategies were developed. The installed system primary energy ratios varied between 1.1 and 2.2 for auxiliary heating and between 1.2 and 2.5 for auxiliary cooling depending on the heat rejection and control strategy chosen. The low electrical energy consumption of the geothermal heat rejection saves 30% of auxiliary electricity and results in an electrical coefficient of performance of 13. The maximum primary energy ratios for solar fractions up to 88% are 2.7 for auxiliary heating and 3.2 for auxiliary cooling, i.e. nearly three times higher than for the reference electrical compression system of 1.2. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712000229# [article] Heat rejection and primary energy efficiency of solar driven absorption cooling systems = Rejet de chaleur et efficacité de l'énergie primaire des systèmes de refroidissement à absorption faisant appel à l'énergie solaire [texte imprimé] / Ursula Eicker, Auteur ; Dirk Pietruschka, Auteur ; Ruben Pesch, Auteur . - 2012 . - pp. 729–738. Génie mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 35 N° 3 (Mai 2012) . - pp. 729–738 Mots-clés : Primary  energy  Absorption  system  Control  Cooling  tower Résumé : Efficient heat rejection is crucial for the overall primary energy balance of sorption systems, as it dominates the auxiliary energy consumption. Low ratios of cooling power to auxiliary electricity of 3.0 or less are still common in sorption system, so that the primary energy efficiency is not always higher than for conventional compression chillers. Whereas dry heat rejection systems require electricity for fan operation, hybrid or wet cooling systems in addition need pumping energy for the cooling water and the water itself. The energy efficiency can be improved for heat rejection to the ground, where only pumping energy is needed for the geothermal heat exchange. Dynamic simulation models were used for a single effect absorption chiller powered by solar thermal collectors via a hot storage tank. The chiller models were coupled to a three dimensional numerical ground heat exchanger model or to cooling tower models. The models were validated with operating data of a 15 kW solar cooling system installed in an office building. Primary energy efficiency ratios were determined for different heat rejection systems and improved control strategies were developed. The installed system primary energy ratios varied between 1.1 and 2.2 for auxiliary heating and between 1.2 and 2.5 for auxiliary cooling depending on the heat rejection and control strategy chosen. The low electrical energy consumption of the geothermal heat rejection saves 30% of auxiliary electricity and results in an electrical coefficient of performance of 13. The maximum primary energy ratios for solar fractions up to 88% are 2.7 for auxiliary heating and 3.2 for auxiliary cooling, i.e. nearly three times higher than for the reference electrical compression system of 1.2. ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712000229#

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