ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Investigation of a packed bed energy storage system with different PCM configurations and heat transfer enhancement with fins using CFD modeling

Mehdi Mehrpooya, Seyed Reza Mirmotahari, Farzad Ghafoorian, Mohammadamin Karimkhani, and Mohammad Reza Ganjali

Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran

E-mail: mehrpoya@ut.ac.ir

Received: 18 November 2023  Accepted: 30 November 2023

Abstract:

In the present study, a two-dimensional CFD approach has been chosen to investigate heat transfer in a packed bed filled with phase change materials (PCM) capsules. In this research, four different geometries, circular, hexagonal, elliptical, and square, are considered PCM packages made of KNO₃ covered with a copper layer and NaK as heat transfer fluid (HTF). The CFD results showed that in the charging mode, the circular geometry performed better and reached the final temperature of 660 K earlier than other geometries. Also, the effect of adding two different types of fins, namely flat and sharp fins to PCM packages, was evaluated and it was found that sharp fins improve heat transfer surface and increase system efficiency. Finally, the effect of HTF inlet velocity and packed bed porosity on the optimum geometry which consists of circular PCM capsules with sharp fins was investigated. The results showed that by increasing the HTF velocity and packed bed porosity, convection and conduction heat transfer improved, and at a velocity of 0.016 and porosity of 0.686, the energy storage system has the highest performance.

Keywords: PCM configurations; CFD approach, packed bed; Energy storage system; Charging mode process; Porosity

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-023-03251-y

Chemical Papers 78 (4) 2453–2467 (2024)