Phase change in multi-tube heat exchangers. (January 2016)

• Record Type: Journal Article
• Authors: Esapour, M.; Hosseini, M.J.; Ranjbar, A.A.; Pahamli, Y.; Bahrampoury, R.
• Is Part Of: Renewable energy. Volume 85(2016)
• Page Start: 1017
• Page End: 1025
• Publication Date: 2016-01
• Subjects: Melting -- Multi-tube heat exchanger -- Number of inner tubes -- Phase change material; Renewable energy sources -- Periodicals; Power resources -- Periodicals; Énergies renouvelables -- Périodiques; Ressources énergétiques -- Périodiques; 333.794
• DOI: 10.1016/j.renene.2015.07.063
• Languages: English
• ISSNs: 0960-1481

Abstract

Abstract: In this paper, melting of a phase change material (PCM) in a multi-tube heat exchanger (MTHX) is investigated. Water, as the heat transfer fluid (HTF), flows through the inner tube/tubes and the outer one while RT35 as the PCM fills the middle. The aim of this study is to investigate the effect of number of inner tubes as a geometrical parameter during charging process. Also consequences of increasing operational parameters including the HTF mass flow rate and inlet temperature are studied. In order to understand the effects of the proposed configurations, a comparison between double pipe and simple MTHX is carried out. Results show that as the inlet temperature increases melting process accelerates and complete melting time reduces, whereas, similar mass flow rate increase doesn't reduce the melting time to such an extent. By increasing the number of inner tubes from 1 to 4 in the shell side of the MTHX, melt region enlarges and its including vortices strengthens which leads to a dominated convective heat transfer and thus a higher melting rate. This increase in number of tubes leads to 29% reduction in melting time. Highlights: The effect of number of tubes is studied in a containing PCM multi-tube heat exchanger. A comparison between double pipe and simple multi-tube heat storage units is presented. Consequences of operational parameters including inlet temperature and flow rate is presented. Geometrical parameters as well as operational ones play a critical role in heat transfer.