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Numerical study on the steady state and transient performance of a multi-type heat pump system / Jong Won Choi 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. 429-443 Titre : Numerical study on the steady state and transient performance of a multi-type heat pump system Titre original : Etude numérique sur le régime permanent et la performance en régime transitoire d’un système à pompe à chaleur polyvalent Type de document : texte imprimé Auteurs : Jong Won Choi, Auteur ; Gilbong Lee, Auteur ; Min Soo Kim, Auteur Année de publication : 2011 Article en page(s) : pp. 429-443 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Heat  pump  System-multi-type  Heat  exchanger  Steady-state  Transient-state  Discharge-superheat Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : Numerical methods are provided to analyze dynamic characteristics as well as steady-state performance of a multi-type heat pump system. Lumped parameter method was applied to simulate the compressor and expansion device. Additionally, fully distributed method was used for analyzing the condenser and evaporators. The transient terms in the governing equations for heat exchangers were solved adopting the wave equation solutions. The simulation results predict the steady-state performance of a heat pump system with the deviation of ±10%. The transient simulation showed satisfactory responses of temperatures and pressures for various compressor speeds or expansion valve openings. From the results, it was shown that the operating conditions of secondary fluid of one indoor unit had minor influence on the performance of the other unit, while opening of expansion valve affected the transient responses of both evaporators significantly. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002331 [article] Numerical study on the steady state and transient performance of a multi-type heat pump system = Etude numérique sur le régime permanent et la performance en régime transitoire d’un système à pompe à chaleur polyvalent [texte imprimé] / Jong Won Choi, Auteur ; Gilbong Lee, Auteur ; Min Soo Kim, Auteur . - 2011 . - pp. 429-443. Génie Mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 34 N° 2 (Mars 2011) . - pp. 429-443 Mots-clés : Heat  pump  System-multi-type  Heat  exchanger  Steady-state  Transient-state  Discharge-superheat Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : Numerical methods are provided to analyze dynamic characteristics as well as steady-state performance of a multi-type heat pump system. Lumped parameter method was applied to simulate the compressor and expansion device. Additionally, fully distributed method was used for analyzing the condenser and evaporators. The transient terms in the governing equations for heat exchangers were solved adopting the wave equation solutions. The simulation results predict the steady-state performance of a heat pump system with the deviation of ±10%. The transient simulation showed satisfactory responses of temperatures and pressures for various compressor speeds or expansion valve openings. From the results, it was shown that the operating conditions of secondary fluid of one indoor unit had minor influence on the performance of the other unit, while opening of expansion valve affected the transient responses of both evaporators significantly. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002331

Studies on the heating capacity control of a multi-type heat pump system applying a multi-input multi-output (MIMO) method / Il Hwan Lee 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. 416-428 Titre : Studies on the heating capacity control of a multi-type heat pump system applying a multi-input multi-output (MIMO) method Titre original : Etudes sur la régulation de la puissance thermique d'un système à pompe à chaleur de type multiple employant une méthode comportant plusieurs grandeurs d'entrée et de sortie Type de document : texte imprimé Auteurs : Il Hwan Lee, Auteur ; Jong Won Choi, Auteur ; Min Soo Kim, Auteur Année de publication : 2011 Article en page(s) : pp. 416-428 Note générale : Génie Mécanique Langues : Anglais (eng) Mots-clés : Capacity  control  Multi-input  Multi-output  Heat  pump  System  Control  Variable  Integral Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : This paper describes a method to control capacity of a multi-type heat pump system. Because indoor units are interconnected, alteration of the heating or cooling setting of one indoor unit can influence the performance of the other indoor units. Proportional-integral (PI) controllers were used to assess system performance, and the PI controllers’ gain values were optimized by using a genetic algorithm. A system model was established following a system identification optimization process, and a pseudo random binary sequence was selected as the system identification input signal. A multi-input multi-output (MIMO) controller was more effective in reducing such cross-coupling effects than a single-input single-output (SISO) controller. The temperature at the secondary fluid outlet in the condenser and the saturation pressure at the evaporator were selected as the control variables in the MIMO controller. The experimental results showed that an optimized MIMO controller could reduce overshoot by up to 40% compared with the results using a SISO controller. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002173 [article] Studies on the heating capacity control of a multi-type heat pump system applying a multi-input multi-output (MIMO) method = Etudes sur la régulation de la puissance thermique d'un système à pompe à chaleur de type multiple employant une méthode comportant plusieurs grandeurs d'entrée et de sortie [texte imprimé] / Il Hwan Lee, Auteur ; Jong Won Choi, Auteur ; Min Soo Kim, Auteur . - 2011 . - pp. 416-428. Génie Mécanique Langues : Anglais (eng) in International journal of refrigeration > Vol. 34 N° 2 (Mars 2011) . - pp. 416-428 Mots-clés : Capacity  control  Multi-input  Multi-output  Heat  pump  System  Control  Variable  Integral Index. décimale : 621.5 Energie pneumatique. Machinerie et outils. Réfrigération Résumé : This paper describes a method to control capacity of a multi-type heat pump system. Because indoor units are interconnected, alteration of the heating or cooling setting of one indoor unit can influence the performance of the other indoor units. Proportional-integral (PI) controllers were used to assess system performance, and the PI controllers’ gain values were optimized by using a genetic algorithm. A system model was established following a system identification optimization process, and a pseudo random binary sequence was selected as the system identification input signal. A multi-input multi-output (MIMO) controller was more effective in reducing such cross-coupling effects than a single-input single-output (SISO) controller. The temperature at the secondary fluid outlet in the condenser and the saturation pressure at the evaporator were selected as the control variables in the MIMO controller. The experimental results showed that an optimized MIMO controller could reduce overshoot by up to 40% compared with the results using a SISO controller. DEWEY : 621.5 ISSN : 0140-7007 En ligne : http://www.sciencedirect.com/science/article/pii/S0140700710002173