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Pompes à chaleur au CO2 transcritique optimisées : comparaison de la performance des capillaires et des détendeurs.

Optimized transcritical CO2 heat pumps: performance comparison of capillary tubes against expansion valves.

Auteurs : AGRAWAL N., BHATTACHARYYA S.

Type d'article : Article, Article de la RIF

Résumé

A capillary tube based CO2 heat pump is unique because of the transcritical nature of the system. The transcritical cycle has two independent parameters, pressure and temperature, unlike the subcritical cycle. In the present study, a steady state simulation model has been developed to evaluate the performance of a capillary tube based transcritical CO2 heat pump system for simultaneous heating and cooling at 73 and 4°C, respectively against optimized expansion valve systems. Capillary tubes of various configurations having diameters of 1.4, 1.5 and 1.6 mm along with internal surface roughness of 0.001-0.003 mm have been tested to obtain the optimum design and operating conditions. Subcritical and supercritical thermodynamic and transport properties of CO2 are calculated employing a precision in-house property code. It is observed that the capillary tube system is quite flexible in response to changes in ambient temperature, almost behaving to offer an optimal pressure control. System performance is marginally better with a capillary tube at higher gas cooler exit temperature. Capillary tube length turns out to be the critical parameter that influences system optimum conditions. A novel nomogram has been developed that can be employed as a guideline to select the optimum capillary tube.

Documents disponibles

Format PDF

Pages : 388-395

Disponible

  • Prix public

    20 €

  • Prix membre*

    Gratuit

* meilleur tarif applicable selon le type d'adhésion (voir le détail des avantages des adhésions individuelles et collectives)

Détails

  • Titre original : Optimized transcritical CO2 heat pumps: performance comparison of capillary tubes against expansion valves.
  • Identifiant de la fiche : 2008-0867
  • Langues : Anglais
  • Source : International Journal of Refrigeration - Revue Internationale du Froid - vol. 31 - n. 3
  • Date d'édition : 05/2008

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