Improved Melting of Latent Heat Storage Using Fin Arrays with Non-Uniform Dimensions and Distinct Patterns

Abstract

Employing phase-change materials (PCM) is considered a very efficient and cost-effective option for addressing the mismatch between the energy supply and the demand. The high storage density, little temperature degradation, and ease of material processing register the PCM as a key candidate for the thermal energy storage system. However, the sluggish response rates during their melting and solidification processes limit their applications and consequently require the inclusion of heat transfer enhancers. This research aims to investigate the potential enhancement of circular fins on intensifying the PCM thermal response in a vertical triple-tube casing. Fin arrays of non-uniform dimensions and distinct distribution patterns were designed and investigated to determine the impact of modifying the fin geometric characteristics and distribution patterns in various spatial zones of the heat exchanger. Parametric analysis on the various fin structures under consideration was carried out to determine the most optimal fin structure from the perspective of the transient melting evolution and heat storage rates while maintaining the same design limitations of fin material and volume usage. The results revealed that changing the fin dimensions with the heat-flow direction results in a faster charging rate, a higher storage rate, and a more uniform temperature distribution when compared to a uniform fin size. The time required to fully charge the storage system (fully melting of the PCM) was found to be reduced by up to 10.4%, and the heat storage rate can be improved by up to 9.3% compared to the reference case of uniform fin sizes within the same fin volume limitations.

Thermal Management of the Melting Process in a Latent Heat Triplex Tube Storage System Using Different Configurations of Frustum Tubes

“…In the system with straight tubes, the hydraulic diameters of the inner, middle, and outer tubes are considered 20 mm, and the thickness of the inner and outer tubes is also considered 1 mm. It should be noted that the dimensions of the base system are chosen based on the triplex tube latent heat storage systems in the literature [65,66]. In addition to the ordinary straight triplex tubes shown in Figure 1(a), there are three more scenarios considered in this study, including changing the middle tube to a frustum tube (Figure 1(b)), changing the inner tube to a frustum tube (Figure 1(c)), and changing both the inner and middle tube to frustum tubes (Figure 1(d)).…”

Evaluation of T-Shaped Fins With a Novel Layout for Improved Melting in a Triple-Tube Heat Storage System

“…In this investigation, LHSHE with circular fins in a vertical direction is studied and optimized. Five T-shaped fins are linked to the interior and exterior pipe inside the middle tube, The dimensions of the triplex tube heat exchanger are selected based on the literature, which can be used in practical applications such as solar collectors and multiple tube heat storage systems (Sun et al, 2021;Najim et al, 2022). The dimensions proposed can also be considered as the whole or a section of a triple-tube heat storage unit.…”

“…Second, the dimension effects of the T-shaped fins body on the thermal behavior of the heat exchanger are investigated while the head sizes of T-shaped fins are fixed and equal to those of the best case obtained in the previous step. Furthermore, as introduced in a previous study by Najim et al (2022), a flat fin is added to the bottom of the vertical triple-tube heat exchanger with Optimum T-shaped Fins to improve the heat transfer performance at the bottom of the system where the natural convection effect is weak. To more clearly evaluate the thermal performance of Optimum T-shaped Fins with a flat fin, liquid fraction development and temperature distributions, melting time, and heat storage rate are discussed in detail for all proposed systems with T-shaped fins and compared with those of No-Fin and Uniform-Fin with and without an added fin to the bottom.…”

Compound Heat Transfer Augmentation of a Shell-and-Coil Ice Storage Unit with Metal-Oxide Nano Additives and Connecting Plates

“…Also, according to their results, the highest obtainable surface efficiency in this system was 78%. In the research conducted by Najim et al [ 11 ], circular fin arrays with non-uniform dimensions were employed to improve the melting rate in a vertical triple-tube (TT) PCM unit. They studied the impact of the distribution and characteristics of these fins on the enhancement of this process.…”