Thermal energy storage in a fluidized bed of PCM

Abstract

The objective of the present work was to research the storage behavior of a fluidized bed filled with a granular phase change material (PCM) with a small particle diameter (d p = 0.54 mm). The performance of the fluidized bed was compared to that of well-known storage methods such as fluidized beds with sand and packed beds based of sand and PCM. For this purpose, heating experiments were conducted in a cylindrical bed with air as the working fluid.The influence of the bed height and flow rate on the storage and recovery efficiencies of the fluidized bed of PCM was analyzed. Additionally, the stability of the PCM during various charging-discharging cycles was studied.The results indicate that this PCM is an alternative material that can be used in fluidized bed systems to increase the efficiency of storing thermal * Corresponding author. NOTICE: this is the author's version of a work that was accepted for publication in Chemical Engineering Journal. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. The cycling test shows that the PCM is stable under bubbling conditions up to 15 cycles, which corresponds to approximately 75 hours of continuous operation. A definitive version was subsequently published in Chemical Engineering

Modeling on heat storage performance of compressed air in a packed bed system

“…Comparison between the present numerical simulation and experimental data in Ref. [31]. similarity in the results is not surprising.…”

“…This section contains a validation of the numerical method according to an example performed by Izquierdo-Barrientos et al [31]. The basic data for validation is shown in Table 4.…”

Experimental heat transfer coefficients between a surface and fixed and fluidized beds with PCM

“…The granular PCM consists of paraffin, which is the material that changes its phase, bounded within a secondary supporting structure of SiO 2 , which ensures that the paraffin does not leak from the granulate when in its liquid form. This material is commercialized by Rubitherm and is similar to that used by Rady [20] and Izquierdo-Barrientos et al [3] in their studies. This PCM is available in two sizes involving particle diameters of 1-3 mm and 0.2-0.6 mm.…”

“…When the heat transfer fluid is air instead of water, packed beds of micro-and macroencapsulated PCMs have traditionally been utilized. More recently, Izquierdo-Barrientos et al [3] studied the performance of a fluidized bed with a granular PCM (with a particle size of 0.54 mm) as an energy storage device. They observed a higher efficiency during the storage process compared with traditional packed beds.…”

Energy storage with PCM in fluidized beds: Modeling and experiments

“…Sozen et al [5] presented an experimental investigation using 25-mm-diameter PCM spheres in a water fluidized bed, showing that with cycling, fluidization yielded less of a loss in heat storage efficiency than was observed under fixed bed conditions. Izquierdo-Barrientos et al [6] presented heating experiments using a granular PCM of 0.54 mm mean diameter in an air fluidized bed, obtaining higher charging efficiencies than in sand beds and stable behavior after 75 hours of continuous operation.…”