Efficient storage and recovery of waste heat by phase change material embedded within additively manufactured grid heat exchangers

https://doi.org/10.1016/j.ijheatmasstransfer.2021.121846Get rights and content
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Highlights

  • Phase change material (PCM) based thermal battery is developed.

  • Additive manufacturing enabled grid heat exchanger design for thermal energy storage.

  • Such thermal batteries offer rapid energy charging-discharging for waste heat recovery.

  • The grid structure enables a more uniform temperature stabilization during melting.

  • These experimental results advocate large-scale PCM storage systems.

Abstract

The low thermal conductivity of organic phase change materials (PCMs) hinders their usage for energy storage purposes. We demonstrate a compact PCM-based thermal battery that employs three-dimensional (3D) printed metal surfaces for a robust thermal energy storage and recovery. The thermal battery could be utilized to store excess heat from various sources. The concept includes organic paraffin and fatty acid PCMs embedded within aluminum silicon alloy grid heat exchangers (GHE) produced via additive manufacturing. The heat exchangers consist of two parts: (i) a planar part with embedded water channels and (ii) a surface extrusion grid outside the planar part embedded in the PCM storage system. Three different grid designs are investigated and compared with a simple planar heat exchanger (PHE) without grid extension. The charging and discharging processes of the thermal battery were analyzed experimentally. The laboratory scale experiments reveal that the 3D printed grid surfaces of GHE significantly reduce the charging and discharging time from more than 240 min to less than 20 min. In contrast to PHE, the GHE may increase thermal power by a factor of 20 from 35 W to 670 W. Furthermore, the grid structure positively restrains the natural convection flow of the PCM melt, increasing conduction in the highly conductive grid structure and resulting in high charging-discharging power of the thermal battery. The swift charging and discharging with high power and energy density make the compact grid thermal battery a promising solution for thermal energy management.

Keywords

Thermal energy storage
Phase change material
Thermal conductivity
Heat transfer
3D printed heat exchanger
Additive manufacturing

Cited by (0)

1

MRY and AL equally first authors.