Evaluation and Improvement of PCM Melting in Double Tube Heat Exchangers Using Different Combinations of Nanoparticles and PCM (The Case of Renewable Energy Systems)

Abstract

In this work, the melting process of phase change material (PCM) in double tube heat exchangers was investigated and evaluated through the use of different combinations (1, 2, 3% Nano-Enhanced PCM and 1, 3, 5% Nano-HTF) of GQD, as well as SWCNT nanoparticles and PCM (RT82). In this study, the effect of three different methods, namely the dispersion of nanoparticles in PCM (nano-enhanced PCM), the dispersion of nanoparticles in HTF (nano-HTF), and the simultaneous dispersion of nanoparticles in PCM and HTF (nano-enhanced PCM, nano-HTF) concerning the nanoparticles participation in the thermal energy storage system in a double tube heat exchanger was evaluated. Other effective factors, such as the inlet fluid temperature, different Reynolds numbers, fin as well as new parameter of pipe, and fin thickness were also evaluated. The results showed that the highest effect of different parameters on the PCM melting process was related to the 1% nano-HTF and 3% nano-enhanced PCM nanoparticles of SWCNT, which decreased the PCM melting rate by about 39%. The evaluation of the effect of pipe and fan thickness also showed that the melting rate improved by 31% through reducing the thickness of the HTF fin and pipe. In general, the current study followed two purposes first, to examine three methods of the dispersion of nanoparticles in the thermal energy storage system; second, to reduce the thickness of the tube and fin. Findings of the study yielded positive results.

The optimum fin length distribution of tabular PCM heat exchanger

“…18 So, the length of fin, fin density, and fin angle are the main effects on PCM HE, in addition to the shape and orientation of PCM HE, these parameters can enhance the melting process but reduce solidification performance and vice versa. 19 The uniform five longitudinal fins used as a reference model that greatly enhances heat performance compared with nonfin HE. Nonetheless, they have a negative effect in terms of showing unequal melting and solidification below and above the tube, the length of the fins should be modified to get the best or optimal heat performance.…”

“…The geometry of PCM HE has a great effect on PCM HE's understanding of melting and solidification processes 18 . So, the length of fin, fin density, and fin angle are the main effects on PCM HE, in addition to the shape and orientation of PCM HE, these parameters can enhance the melting process but reduce solidification performance and vice versa 19 …”

The Optimum Fins Length Distribution of Tabular PCM Heat Exchanger

“…has a great effect on PCM H.E., the full understand of melting and solidification processes, where the natural convection is dominated mode of heat transfer, that depend in density change, and this natural convection up stream can restricted or enhance by geometry of container (Huang, Yang et al 2022). So, the length of fin, fin density and fin angle are the main effects on PCM H.E., in addition of shape and orientation of PCM H.E., these parameters can enhance melting process but reduce solidification performance and vice versa (Motevali, Hasandust Rostami et al 2021).…”

Microencapsulated Phase Change Materials for Thermal Energy Storage in Buildings: Design, Characterization and Modelling

“…Several researchers [176]- [185], [186]- [189] have tested numerically and experimentally double-pipe LHTES systems. A double tube LHTES with RT82 as PCM with the dispersion of graphene quantum dot and single-walled carbon nanotubes were studied numerically with Ansys Fluent [176]. The results indicated that reducing pipe and fin thickness by 0.5mm (from 1.5 mm to 1mm) reduced the melting rate by 31% [176].…”

“…A double tube LHTES with RT82 as PCM with the dispersion of graphene quantum dot and single-walled carbon nanotubes were studied numerically with Ansys Fluent [176]. The results indicated that reducing pipe and fin thickness by 0.5mm (from 1.5 mm to 1mm) reduced the melting rate by 31% [176]. A concentric double tube containing Al2O3 nanofluid and n-eicosane was studied experimentally, and the results indicated that the average heat transfer effectiveness was increased with an increased flow ratio [177].…”