Analytical solution for the simultaneous heat and mass transfer problem in air washers / J. C. Santos in International journal of refrigeration, Vol. 34 N° 1 (Janvier 2011)  

Public ISBD [article]  inInternational journal of refrigeration > Vol. 34 N° 1 (Janvier 2011) . - pp. 353-361 Titre : Analytical solution for the simultaneous heat and mass transfer problem in air washers Titre original : Solution analytique du problème de transfert simultané de chaleur et de masse dans un laveur d'air Type de document : texte imprimé Auteurs : J. C. Santos, Auteur ; J.M. Medeiros, Auteur Année de publication : 2011 Article en page(s) : pp. 353-361 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Air conditioning washer Evaporative system Calculation Heat transfer Mass Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : An analytical solution approach for the simultaneous heat and mass transfer problem in air washers operating as evaporative coolers is presented. A one-dimensional model using the coupled mass and energy balance equations in the air washer is presented. Then, starting from a linear approach for the experimental curve of the air saturation, an analytical solution for the model was derived. The solution showed an excellent agreement with the available results found in the literature. The influence of several important parameters for the cooling process such as temperature and ambient air humidity, air flow rate and feeding water temperature, in the air cooling rate was investigated. The efficacy of the process can be greatly increased by reducing the cooling water temperature and the applied air flow rate. The analytical solution can be easily included into the models used for simulating desiccant air-conditioning systems operating in conjunction with air washers. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710001465 [article] Analytical solution for the simultaneous heat and mass transfer problem in air washers = Solution analytique du problème de transfert simultané de chaleur et de masse dans un laveur d'air [texte imprimé] / J. C. Santos, Auteur ; J.M. Medeiros, Auteur . - 2011 . - pp. 353-361. Génie Mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 34 N° 1 (Janvier 2011) . - pp. 353-361 Mots-clés : Air conditioning washer Evaporative system Calculation Heat transfer Mass Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : An analytical solution approach for the simultaneous heat and mass transfer problem in air washers operating as evaporative coolers is presented. A one-dimensional model using the coupled mass and energy balance equations in the air washer is presented. Then, starting from a linear approach for the experimental curve of the air saturation, an analytical solution for the model was derived. The solution showed an excellent agreement with the available results found in the literature. The influence of several important parameters for the cooling process such as temperature and ambient air humidity, air flow rate and feeding water temperature, in the air cooling rate was investigated. The efficacy of the process can be greatly increased by reducing the cooling water temperature and the applied air flow rate. The analytical solution can be easily included into the models used for simulating desiccant air-conditioning systems operating in conjunction with air washers. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710001465

Exemplaires

Code-barres	Cote	Support	Localisation	Section	Disponibilité
aucun exemplaire

Energy and exergy analysis applied to the evaporative cooling process in air washers / J. C. Santos in International journal of refrigeration, Vol. 36 N° 3 (Mai 2013)  

Public ISBD [article]  inInternational journal of refrigeration > Vol. 36 N° 3 (Mai 2013) . - pp. 1154–1161 Titre : Energy and exergy analysis applied to the evaporative cooling process in air washers Titre original : Analyse énergétique et exergétique appliquée au procédé de refroidissement évaporatif dans les laveurs d'air Type de document : texte imprimé Auteurs : J. C. Santos, Auteur ; G. D. T. Barros, Auteur ; J. M. Gurgel, Auteur Année de publication : 2013 Article en page(s) : pp. 1154–1161 Note générale : Refrigeration Langues : Anglais (eng) Mots-clés : Evaporative cooling  Air washer  Saturation effectiveness  Second law Résumé : This paper presents a study on the performance of the evaporative cooling process in air washers with the use of mass balances, energy and exergy equations. Usually, the performance of these devices is described in terms of their saturation effectiveness based on energy analysis. This method, however, is inappropriate to identify the main sources of irreversibility within the process. It is also unsuitable to give the optimum conditions for operating the system with a proper use of energy resources. Thus, an exergy analysis was developed to complement the energy analysis of the process. A mathematical model based on mass and energy balances was used to determine the water and air properties in the washer. The influence of the humidity and temperature of the air and water at the inlet, the washer length in the saturation effectiveness, and the second law efficiency was investigated. The results showed that the best condition of the intake air for obtaining thermal comfort does not coincide with the best condition for the thermodynamic performance of the system. The energy and exergy analyses were carried out simultaneously to generate the conditions required for optimum performance with minimal exergy depletion. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712003556 [article] Energy and exergy analysis applied to the evaporative cooling process in air washers = Analyse énergétique et exergétique appliquée au procédé de refroidissement évaporatif dans les laveurs d'air [texte imprimé] / J. C. Santos, Auteur ; G. D. T. Barros, Auteur ; J. M. Gurgel, Auteur . - 2013 . - pp. 1154–1161. Refrigeration Langues : Anglais (eng) in International journal of refrigeration > Vol. 36 N° 3 (Mai 2013) . - pp. 1154–1161 Mots-clés : Evaporative cooling  Air washer  Saturation effectiveness  Second law Résumé : This paper presents a study on the performance of the evaporative cooling process in air washers with the use of mass balances, energy and exergy equations. Usually, the performance of these devices is described in terms of their saturation effectiveness based on energy analysis. This method, however, is inappropriate to identify the main sources of irreversibility within the process. It is also unsuitable to give the optimum conditions for operating the system with a proper use of energy resources. Thus, an exergy analysis was developed to complement the energy analysis of the process. A mathematical model based on mass and energy balances was used to determine the water and air properties in the washer. The influence of the humidity and temperature of the air and water at the inlet, the washer length in the saturation effectiveness, and the second law efficiency was investigated. The results showed that the best condition of the intake air for obtaining thermal comfort does not coincide with the best condition for the thermodynamic performance of the system. The energy and exergy analyses were carried out simultaneously to generate the conditions required for optimum performance with minimal exergy depletion. En ligne : http://www.sciencedirect.com/science/article/pii/S0140700712003556

Exemplaires

Code-barres	Cote	Support	Localisation	Section	Disponibilité
aucun exemplaire

Steam reforming of ethanol on copper catalysts derived from hydrotalcite-like materials / A. F. Cunha in Industrial & engineering chemistry research, Vol. 51 N° 40 (Octobre 2012)  

Public ISBD [article]  inIndustrial & engineering chemistry research > Vol. 51 N° 40 (Octobre 2012) . - pp. 13132-13143 Titre : Steam reforming of ethanol on copper catalysts derived from hydrotalcite-like materials Type de document : texte imprimé Auteurs : A. F. Cunha, Auteur ; Y. J. Wu, Auteur ; J. C. Santos, Auteur Année de publication : 2012 Article en page(s) : pp. 13132-13143 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Catalyst Steam reforming Résumé : Steam reforming of ethanol (SRE) and sorption enhanced steam reforming of ethanol (SE-SRE) on Cu,Zn,Al matenals was studied in the temperature range between 200 and 600 °C for hydrogen production. Precursors with different structures, such as a hydrotalcite-like compound (CuZnAl-HT), zincian malachite derivative (CuZnAl-REF, a reference catalyst precursor for the synthesis of methanol) and amorphous material with embedded copper particles (CuZnAl-ECP), were employed to obtain the active phases. Among the three samples used, the CuZnAl-HT catalyst shows the highest activity (ethanol and water conversion) and selectivity (hydrogen yield). This material also shows a satisfying stability, as the ethanol conversion only decreases around 20% at 400 °C during 12 h of lifetime test. In addition, carbon dioxide uptake during the transient period of SRE was found on the CuZnAl based materials. Especially for the CuZnAl-HT catalyst a SE-SRE phenomena was perfectly observed at 400 °C due to a relative good interaction of carbon dioxide formed in the initial transient period of reaction and the ZnO phase present in the catalyst. Probably, also retained traces of the hydrotalcite-like precursor structure on the CuZnAl-HT catalyst used are responsible for the observed SE-SRE phenomena. Breakthrough tests were performed with the CuZnAl-HT catalyst. This material shows a carbon dioxide adsorption capacity from 0.11 to 0.18 mol/kg, which is a prerequisite for SE-SRE. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26451462 [article] Steam reforming of ethanol on copper catalysts derived from hydrotalcite-like materials [texte imprimé] / A. F. Cunha, Auteur ; Y. J. Wu, Auteur ; J. C. Santos, Auteur . - 2012 . - pp. 13132-13143. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 51 N° 40 (Octobre 2012) . - pp. 13132-13143 Mots-clés : Catalyst Steam reforming Résumé : Steam reforming of ethanol (SRE) and sorption enhanced steam reforming of ethanol (SE-SRE) on Cu,Zn,Al matenals was studied in the temperature range between 200 and 600 °C for hydrogen production. Precursors with different structures, such as a hydrotalcite-like compound (CuZnAl-HT), zincian malachite derivative (CuZnAl-REF, a reference catalyst precursor for the synthesis of methanol) and amorphous material with embedded copper particles (CuZnAl-ECP), were employed to obtain the active phases. Among the three samples used, the CuZnAl-HT catalyst shows the highest activity (ethanol and water conversion) and selectivity (hydrogen yield). This material also shows a satisfying stability, as the ethanol conversion only decreases around 20% at 400 °C during 12 h of lifetime test. In addition, carbon dioxide uptake during the transient period of SRE was found on the CuZnAl based materials. Especially for the CuZnAl-HT catalyst a SE-SRE phenomena was perfectly observed at 400 °C due to a relative good interaction of carbon dioxide formed in the initial transient period of reaction and the ZnO phase present in the catalyst. Probably, also retained traces of the hydrotalcite-like precursor structure on the CuZnAl-HT catalyst used are responsible for the observed SE-SRE phenomena. Breakthrough tests were performed with the CuZnAl-HT catalyst. This material shows a carbon dioxide adsorption capacity from 0.11 to 0.18 mol/kg, which is a prerequisite for SE-SRE. ISSN : 0888-5885 En ligne : http://cat.inist.fr/?aModele=afficheN&cpsidt=26451462

Exemplaires

Code-barres	Cote	Support	Localisation	Section	Disponibilité
aucun exemplaire