Exergy Analysis and Process Optimization with Variable Environment Temperature - Laboratoire d'Informatique pour la Mécanique et les Sciences de l'Ingénieur Accéder directement au contenu
Article Dans Une Revue Energies Année : 2019

Exergy Analysis and Process Optimization with Variable Environment Temperature

Résumé

In its usual definition, exergy cancels out at the ambient temperature which is thus taken both as a constant and as a reference. When the fluctuations of the ambient temperature, obviously real, are considered, the temperature where exergy cancels out can be equated, either to the current ambient temperature (thus variable), or to a constant reference temperature. Thermodynamic consequences of both approaches are mathematically derived. Only the second approach insures that minimizing the exergy loss maximizes performance in terms of energy. Moreover, it extends the notion of reversibility to the presence of an ideal heat storage. When the heat storage is real (non-ideal), the total exergy loss includes a component specifically related to the heat exchanges with variable ambient air. The design of the heat storage can then be incorporated into an optimization procedure for the whole process. That second approach with a constant reference is exemplified in the case study of heat pumping for heating a building in wintertime. The results show that the so-obtained total exergy loss is the lost mechanical energy, a property that is not verified when exergy analysis is conducted following the first approach.
Fichier principal
Vignette du fichier
Pons_energies-2019-12-04655.pdf (1.52 Mo) Télécharger le fichier
Origine : Fichiers éditeurs autorisés sur une archive ouverte
Loading...

Dates et versions

hal-02401535 , version 1 (10-12-2019)

Identifiants

Citer

Michel Pons. Exergy Analysis and Process Optimization with Variable Environment Temperature. Energies, 2019, 12, pp.4655:1-19. ⟨10.3390/en12244655⟩. ⟨hal-02401535⟩
38 Consultations
46 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More