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Analyse des cycles frigorifiques en cascade avec compression de vapeur d'un seul frigorigène utilisant une méthode de minimisation de la génération d'entropie.

A generalized analysis for cascading single fluid vapor compression refrigeration cycles using an entropy generation minimization method.

Auteurs : RATTS E. B., BROWN J. S.

Type d'article : Article, Article de la RIF

Résumé

This paper focuses on cascading an ideal vapor compression cycle and determining the optimal intermediate temperatures based on the entropy generation minimization method. Only superheating and throttle losses of the cycle are considered since they are inherent to the ideal vapor compression refrigeration cycle. The second law equations have been developed in terms of specific heats and temperature ratios with the intent of reducing involved property modelling. Also the entropy generation was expressed in terms of a single independent variable and minimized to develop an advanced rule for selecting optimum intermediate temperatures. Results for a cascade system operating between reduced temperatures of 0.684 and 0.981 with R134a as the working fluid are presented. The approximate method presented here predicted the optimum reduced temperature for a two-stage system to be 0.88, a difference of 2% from the optimum. The method presented was a much better predictor of the optimum temperature than the geometric mean method which was 0.82, a difference of 5% from the optimum. The entropy generation distribution of the optimum solution was investigated. For a two-stage system, the lower stage and higher stage entropy generation was 44 and 56%, respectively. In comparison to the single stage, the two-stage reduced losses by 78%.

Documents disponibles

Format PDF

Pages : 353-365

Disponible

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    20 €

  • Prix membre*

    Gratuit

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Détails

  • Titre original : A generalized analysis for cascading single fluid vapor compression refrigeration cycles using an entropy generation minimization method.
  • Identifiant de la fiche : 2000-2486
  • Langues : Anglais
  • Source : International Journal of Refrigeration - Revue Internationale du Froid - vol. 23 - n. 5
  • Date d'édition : 08/2000

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