Partager

Des coefficients de transfert de chaleur plus élevés au voisinage du point critique du CO2 : une opportunité pour une efficacité élevée.

Excellent heat rejection from CO2 near the critical point: opportunity for high efficiency.

Auteurs : KONDOU C., HRNJAK P.

Résumé

This paper is focused on heat rejection from CO2 flow near the critical point which is the condition outdoor units of a/c and refrigeration systems spend most of operation hours. The experimental results are provided: heat transfer coefficients (HTC) and pressure drop at mass flux 100 to 240 kg/m2.s and pressure 5, 6, and 7.5 MPa in a horizontal smooth tube of 6.1 mm inner diameter. Data are compared to correlations proposed for other working fluids or other conditions. Heat rejection process is categorized as occurring in superheated, two-phase, and subcooled zone which bulk mean refrigerant temperature being superheated, saturated, and subcooled respectively. Results show much higher values of HTC than correlation proposed for single-phase turbulent flow in superheated zone. The occurrence of condensation in superheat zone is assumed when tube wall temperature is below saturation temperature. The results show that simplified calculations of heat rejection in superheated zone significantly oversize the condenser.

Documents disponibles

Format PDF

Disponible

  • Prix public

    20 €

  • Prix membre*

    15 €

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

Détails

  • Titre original : Excellent heat rejection from CO2 near the critical point: opportunity for high efficiency.
  • Identifiant de la fiche : 2011-0030
  • Langues : Anglais
  • Source : IIR/Eurotherm sustainable refrigeration and heat pump technology conference. Proceedings of the Eurotherm Seminar No. 88, Stockholm, Sweden, June 13-16, 2010.
  • Date d'édition : 13/06/2010

Liens


Voir d'autres communications du même compte rendu (49)
Voir le compte rendu de la conférence

Indexation