Controllable loop thermosyphon (CLT) can be used as a significant temperature management component in solar- and electric-powered cool-storage refrigerators. However, the behaviours of CLT with non-condensable gas (NCG) under active control require further investigation. In this study, air is mixed in working fluid R134a as NCG to evaluate the steady-state and start-stop performances of CLT for selected control modes. CLT with 0–0.62% NCG is tested. The larger the amount of NCG is, the lower the heat transfer rate is. When the mass ratio of NCG reaches 0.62%, the steady-state heat transfer rate varies from 245.0 W to the minimum 118.6 W for different heat sink temperatures. This finding means that CLT loses efficacy due to the excess NCG. In addition, the start-up performances of the two modes decrease as the mass ratio of NCG increases to 0.31% and become entirely unacceptable when NCG reaches 0.47%. By contrast, the stopping time of CLT remains less than 100 s in various conditions. Results indicate that the mass ratio of NCG should be less than 0.47%, and CLT with NCG is suggested to be controlled by the valve in the vapour line.
Effect of non-condensable gas on the behaviours of a controllable loop thermosyphon under active control
Michele Bottarelli;
2019
Abstract
Controllable loop thermosyphon (CLT) can be used as a significant temperature management component in solar- and electric-powered cool-storage refrigerators. However, the behaviours of CLT with non-condensable gas (NCG) under active control require further investigation. In this study, air is mixed in working fluid R134a as NCG to evaluate the steady-state and start-stop performances of CLT for selected control modes. CLT with 0–0.62% NCG is tested. The larger the amount of NCG is, the lower the heat transfer rate is. When the mass ratio of NCG reaches 0.62%, the steady-state heat transfer rate varies from 245.0 W to the minimum 118.6 W for different heat sink temperatures. This finding means that CLT loses efficacy due to the excess NCG. In addition, the start-up performances of the two modes decrease as the mass ratio of NCG increases to 0.31% and become entirely unacceptable when NCG reaches 0.47%. By contrast, the stopping time of CLT remains less than 100 s in various conditions. Results indicate that the mass ratio of NCG should be less than 0.47%, and CLT with NCG is suggested to be controlled by the valve in the vapour line.File | Dimensione | Formato | |
---|---|---|---|
Printed paper-ATE-20181005-1-s2.0-S1359431118307658-main.pdf
solo gestori archivio
Descrizione: Full text editoriale
Tipologia:
Full text (versione editoriale)
Licenza:
NON PUBBLICO - Accesso privato/ristretto
Dimensione
1.46 MB
Formato
Adobe PDF
|
1.46 MB | Adobe PDF | Visualizza/Apri Richiedi una copia |
cao2019.pdf
accesso aperto
Descrizione: Post-print
Tipologia:
Post-print
Licenza:
Creative commons
Dimensione
1.22 MB
Formato
Adobe PDF
|
1.22 MB | Adobe PDF | Visualizza/Apri |
I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.