Characterization of granular phase change materials for thermal energy storage applications in fluidized beds

Abstract

Granular PCMs are tested in 3D and 2D fluidized beds. Density, particle size and angle of repose were measured for different granular PCMs. DSC measurements confirm that there is no loss of material after fluidization.

A review of solar thermal energy storage in beds of particles: Packed and fluidized beds

“…For some samples they observed that at certain temperatures, the particles agglomerated, in a similar manner that Izquierdo- Barrientos et al (2016d) observed for granular PCMs. Although Diago et al (2018) indicated that the agglomeration was soft, it can provoque the defluidization of the bed.…”

“…Another application of heat storage in a fluidized bed of PCM was stud-ied by Belmonte et al (2016), who conducted TRNSYS simulations of the heating system of a single-family house consisting of a solar air heater integrated with a fluidized bed energy storage unit that contained the same granular PCM employed by Izquierdo-Barrientos et al (2016d). Figure 46 shows the schematic of the system simulated.…”

“…2 and 0.6 mm, and a coarser grade, with diameters between 1 and 3 mm. The smaller grade is composed of Geldart B particles, which are more suitable for a bubbling fluidized bed, while the larger grade is composed of Geldart D particles, which are more suited for use in a packed bed(Izquierdo-Barrientos et al, 2016d) Rady (2009a). experimentally studied the materials GR27 and GR41 (the number represents their approximate phase change temperature in degrees Celsius) in a column with an internal diameter of 45 mm and a test section height of 200 mm, and they developed a simple two-phase numerical model for the heat transfer process Rady (2009a).…”

“…(1988) to study the performance of a fluidized bed coupled with a solar concentrator. Their results showed that there is a ratio between the area of the bed and the area of the concentrator that maximizes the efficiency of the system.The more recent works byIzquierdo-Barrientos et al (2013 compared the performance of a fluidized bed with a sensible material (Geldart B sand particles) and one with the granular PCM from Rubitherm described in Section 2.2.1, but with a low particle size more suitable for use in a fluidized bed(Izquierdo-Barrientos et al, 2016d).Rady (2009a,b) andIzquierdo-Barrientos et al (2013, 2016b, in their studies for packed beds with PCM, used granular PCMs with particle sizes between 1 and 3 mm, whereas Izquierdo-Barrientos et al (2013Barrientos et al ( , 2015a used the same material but with a particle size between 0.2 and 0.6 mm, which belongs to Geldart B particles (Izquierdo-Barrientos et al, 2016d). The experimental results presented by Izquierdo-Barrientos et al (2013, 2015a) corroborate the well-mixed behavior of the fluidized bed with sand.…”

Experimental study of fixed and fluidized beds of PCM with an internal heat exchanger

“…Moreover, the measured heat transfer coefficients to a horizontal cylindrical surface immersed in the bed were higher for the fluidized bed than for the fixed bed and for a granular PCM bed than for a bed of sand used as a reference material [12]. The tested granular PCM, which had a phase change temperature of approximately 50 C, did not present agglomeration problems, and although it suffered some attrition after 75 h of continuous operation with 15 charging-discharging cycles, no evidence of PCM loss was observed, and the energy storage capacity of the fluidized particles was unaffected [13].…”