Documents disponibles écrits par cet auteur

Experimental investigations on adiabatic capillary tube in a transcritical CO2 heat pump system for simultaneous water cooling and heating / Neeraj Agrawal in International journal of refrigeration, Vol. 34 N° 2 (Mars 2011) 

Public ISBD [article]  in International journal of refrigeration > Vol. 34 N° 2 (Mars 2011) . - pp. 476-483 Titre : Experimental investigations on adiabatic capillary tube in a transcritical CO2 heat pump system for simultaneous water cooling and heating Titre original : Etudes expérimentales sur le tube capillaire adiabatique d'un système à pompe à chaleur au CO2 transcritique utilisé pour le refroidissement et le chauffage simultanés d'eau Type de document : texte imprimé Auteurs : Neeraj Agrawal, Auteur ; Souvik Bhattacharyya, Auteur Année de publication : 2011 Article en page(s) : pp. 476-483 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Capillary  Heat  pump  Refrigerant  charge  Compressor Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : Experimental studies for a prototype CO2 heat pump system employing capillary tube as an expansion device for simultaneous water heating and cooling have been presented. Tests were conducted with two stainless steel capillary tubes having specifications of ID = 1.71 mm, L = 2.95 m, εc = 3.92 μm and ID = 1.42 mm, L = 1.0 m, εc = 5.76 μm. System performance is significantly influenced by gas cooler water inlet temperature, whereas the effect of water flow rate on system performance is modest. An optimum charge is also recorded at which the system yields the best COP with a capillary tube. Performance deterioration is more severe at undercharged condition than at overcharged condition. Comparisons of test data with simulated results show that maximum deviation in mass flow rate of refrigerant is about ±10% and the flow characteristics exhibit a reasonably good match with the test data. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002227 [article] Experimental investigations on adiabatic capillary tube in a transcritical CO2 heat pump system for simultaneous water cooling and heating = Etudes expérimentales sur le tube capillaire adiabatique d'un système à pompe à chaleur au CO2 transcritique utilisé pour le refroidissement et le chauffage simultanés d'eau [texte imprimé] / Neeraj Agrawal, Auteur ; Souvik Bhattacharyya, Auteur . - 2011 . - pp. 476-483. Génie Mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 34 N° 2 (Mars 2011) . - pp. 476-483 Mots-clés : Capillary  Heat  pump  Refrigerant  charge  Compressor Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : Experimental studies for a prototype CO2 heat pump system employing capillary tube as an expansion device for simultaneous water heating and cooling have been presented. Tests were conducted with two stainless steel capillary tubes having specifications of ID = 1.71 mm, L = 2.95 m, εc = 3.92 μm and ID = 1.42 mm, L = 1.0 m, εc = 5.76 μm. System performance is significantly influenced by gas cooler water inlet temperature, whereas the effect of water flow rate on system performance is modest. An optimum charge is also recorded at which the system yields the best COP with a capillary tube. Performance deterioration is more severe at undercharged condition than at overcharged condition. Comparisons of test data with simulated results show that maximum deviation in mass flow rate of refrigerant is about ±10% and the flow characteristics exhibit a reasonably good match with the test data. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002227

Thermodynamic analysis and optimization of a novel two-stage transcritical N2O cycle / Neeraj Agrawal in International journal of refrigeration, Vol. 34 N° 4 (Juin 2011) 

Public ISBD [article]  in International journal of refrigeration > Vol. 34 N° 4 (Juin 2011) . - pp. 991-999 Titre : Thermodynamic analysis and optimization of a novel two-stage transcritical N2O cycle Titre original : Analyse thermodynamique et optimisation d'un nouveau cycle au N2O biétagé transcritique Type de document : texte imprimé Auteurs : Neeraj Agrawal, Auteur ; Jahar Sarkar, Auteur ; Souvik Bhattacharyya, Auteur Année de publication : 2011 Article en page(s) : pp. 991-999 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Carbon  dioxide  Nitrous  oxide  Two-stage  system  Inter-stage  pressure  Exergy  Optimisation Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : Thermodynamic (energy and exergy) analyses and optimization studies of two-stage transcritical N2O and CO2 cycles, incorporating compressor intercooling, are presented based on cycle simulation employing simultaneous optimization of intercooler pressure and gas cooler pressure. Further, performance comparisons with the basic single-stage cycles are also presented. The N2O cycle exhibits higher cooling COP, lower optimum gas cooler pressure and discharge temperature and higher second law efficiency as compared to an equivalent CO2 cycle. However, two-stage compression with intercooling yields lesser COP improvement for N2O compared to CO2. Based on the cycle simulations, correlations of optimum gas cooler pressure and inter-stage pressure in terms of gas cooler exit temperature and evaporator temperature are obtained. This is expected to be of help as a guideline in optimal design and operation of such systems. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711000284 [article] Thermodynamic analysis and optimization of a novel two-stage transcritical N2O cycle = Analyse thermodynamique et optimisation d'un nouveau cycle au N2O biétagé transcritique [texte imprimé] / Neeraj Agrawal, Auteur ; Jahar Sarkar, Auteur ; Souvik Bhattacharyya, Auteur . - 2011 . - pp. 991-999. Génie Mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 34 N° 4 (Juin 2011) . - pp. 991-999 Mots-clés : Carbon  dioxide  Nitrous  oxide  Two-stage  system  Inter-stage  pressure  Exergy  Optimisation Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : Thermodynamic (energy and exergy) analyses and optimization studies of two-stage transcritical N2O and CO2 cycles, incorporating compressor intercooling, are presented based on cycle simulation employing simultaneous optimization of intercooler pressure and gas cooler pressure. Further, performance comparisons with the basic single-stage cycles are also presented. The N2O cycle exhibits higher cooling COP, lower optimum gas cooler pressure and discharge temperature and higher second law efficiency as compared to an equivalent CO2 cycle. However, two-stage compression with intercooling yields lesser COP improvement for N2O compared to CO2. Based on the cycle simulations, correlations of optimum gas cooler pressure and inter-stage pressure in terms of gas cooler exit temperature and evaporator temperature are obtained. This is expected to be of help as a guideline in optimal design and operation of such systems. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700711000284