Analysis of a twisted double-pipe heat exchanger with lobed cross-section as a novel heat storage unit for solar collectors using phase-change material
TL;DR: In this paper, a twisted double-pipe heat exchanger containing phase change material is designed and analyzed as an energy storage unit in solar collectors, and the effects of several parameters like pipe's position, twisting, and cross-section on the PCM melting in the storage unit have been investigated.
About: This article is published in International Communications in Heat and Mass Transfer.The article was published on 2021-11-01. It has received 10 citations till now. The article focuses on the topics: Phase-change material & Heat transfer.
Citations
More filters
TL;DR: In this paper , an innovative anchor-type longitudinal fin design that copes with the sluggish phase change process in shell-and-tube ice storage units by covering the regions between the conventional fin is introduced.
23 citations
TL;DR: In this article , the authors investigated the compound heat transfer enhancement of a cylindrical-shaped unit equipped with double helically coiled coolant tubes using connecting plates and nano additives as heat transfer augmentation methods.
Abstract: Due to the high enthalpy of fusion in water, ice storage systems are known as one of the best cold thermal energy storage systems. The phase change material used in these systems is water, thus it is inexpensive, accessible, and completely eco-friendly. However, despite the numerous advantages of these systems, the phase change process in them is time-consuming and this leads to difficulties in their practical application. To solve this problem, the addition of nanomaterials can be helpful. This study aims to investigate the compound heat transfer enhancement of a cylindrical-shaped unit equipped with double helically coiled coolant tubes using connecting plates and nano additives as heat transfer augmentation methods. Complex three-dimensional numerical simulations are carried out here to assess the best heat exchanger material as well as the impact of various nanoparticle types, including alumina, copper oxide, and titania, and their concentrations in the PCM side of the ice storage unit. The influence of these parameters is discussed on the charging rate and the temperature evolution factor in these systems. The results suggest that using nano additives, as well as the connecting plates, together is a promising way to enhance the solidification rate by up to 29.9%.
16 citations
TL;DR: In this paper , the role of phase change material (PCM) in improving the thermal management performance of the fast charging module is explored, and a comparative analysis of thermal management system performance with and without the PCM is performed.
6 citations
TL;DR: In this article , a 3D double-pipe helical coil heat exchanger containing phase-change material (PCM) was investigated as a thermal storage system in solar water heaters, and the impact of some critical geometrical parameters, like helical pitch, inner and outer pipe diameter, and some flow parameters, such as fluid inlet temperature and Reynolds number, were analyzed.
Abstract: This research investigates a 3-D double-pipe helical coil heat exchanger containing Phase-Change Material (PCM) as a thermal storage system in solar water heaters. A concentric double-pipe follows the helical profile upward and creates a heat storage unit. In the unit, water in turbulent mode flows in the inner pipe as a Heat Transfer Fluid (HTF), and RT-50 is considered PCM placed in the annulus. This heat exchanger with all related conditions is modeled in Ansys Fluent 19 software, and we used the k-ε RNG turbulence model to simulate turbulent flow. For evaluating this novel model of thermal storage unit, the impact of some critical geometrical parameters, like helical pitch, inner and outer pipe diameter, and some flow parameters, such as fluid inlet temperature and Reynolds number, have been analyzed. The most important outcomes of the investigation show that inlet temperature and inner and outer pipe diameter are critical factors for the storage system's design. A 1.5 % change in inlet temperature will enhance the melting rate by 27 %. Also, by increasing the inner pipe diameter by 42 %, the melting process was improved by 92 %, while the outer pipe diameter was inversely related to the melting rate. A 20 % increase in this parameter's value showed a 52 % reduction in the melting. Moreover, the change in the helical pitch could not significantly affect the PCM melting process, and for a 300 % increase in pitch size, the melting process increases only by 0.6 %. • PCM melting in double-pipe helical coil TES unit in a solar water heater is studied. • With turbulent HTF flow, the Reynolds number has no major effect on the melting. • Increasing HTF inlet temperature or inner coil diameter increases the melting rate. • Reducing the outer pipe diameter increases the PCM melting process. • The helical pitch has no significant effect on the melting rate.
6 citations
TL;DR: In this article , the authors discuss the influence of various geometrical and material parameters on the melting and solidification processes, as well as the orientation of the heat transfer surface within the storage tank.
4 citations
References
More filters
TL;DR: In this article, a tree-shaped fin with one and two bifurcations was proposed to enhance the performance of a shell-and-tube LHTES unit.
395 citations
TL;DR: In this paper, the augmentation in heat transfer for a shell and tube type LHSU is estimated by carrying out experimental analysis with three longitudinal fins installed on the heat transfer fluid (HTF) tube.
302 citations
TL;DR: In this article, numerical simulations are performed for symmetric melting of phase change material between two cylinders in concentric and eccentric arrays using the FLUENT software which is sub-cooled initially to 1°C.
187 citations
TL;DR: In this article, the authors used a concentric annulus storage system with Erythritol (melting point of 117.7 °C) as a phase change material (PCM) and augmented with longitudinal fins on the shell side, to assess the thermal behavior and heat transfer characteristics of this system.
139 citations
TL;DR: In this article, a mixture of nanoparticles M o S 2 − F e 3 O 4 called Hybrid Nano-Particles (HNP) is applied at different concentrations to the phase change materials (PCM) to compensate for unfavorable ramifications of single type nanoparticles.
133 citations