Exergy analysis of latent heat storage systems with sensible heating and subcooling of PCM

✍ Scribed by A. Venkata Ramayya; K. N. Ramesh

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 159 KB
• Volume: 22
• Category: Article
• ISSN: 0363-907X
• DOI: 10.1002/(sici)1099-114x(199804)22:5<411::aid-er367>3.0.co;2-q

✦ Synopsis

The effect of sensible heating of the phase-change material (PCM) before melting and subcooling after solidification, on the performance of the latent heat storage system (LHSS), is studied in terms of first-and second-law efficiencies for the overall charge-discharge cycle. The external heat transfer irreversibilities on account of the interaction between the heat transfer fluid and the storage element are characterized and the optimum phase-change temperature for maximum second-law efficiency is studied. The performance of the LHSS operation is assessed with and without sensible heating before melting and subcooling after solidification. It is observed that the optimum phase-change temperature is higher, and, the overall second-law efficiency is greater for LHSS with sensible heating and subcooling beyond a certain phase-change temperature compared to latent heat storage alone. In addition, the first-law overall efficiency is found to exhibit a minimum and a pre-heated discharge stream is shown to result in a substantial improvement of the second-law efficiency.