Shape-Stabilized Phase Change Material by a Synthetic/Natural Hybrid Composite Foam with Cell-Wall Pores

Abstract

Improving energy efficiency of buildings reduces energy costs and helps meet the ever increasing world energy demand. Innovative building design requires high-performance structural materials with mechanical integrity, energy efficiency, and sustainability. Here, we report a polyurethane/lignin hybrid structural composite with cell-wall pores for the shape stabilization of an organic phase change material (PCM) as an active energy component in buildings. Sub-50 μm pores on the cell wall of the lignin-based rigid polyurethane (LRPU) foam, which were barely seen in ordinary RPU foams, enabled the very high loading and retention of n-eicosane as the organic PCM, yielding a PCM loading of 93% with negligible loss after extensive drying at 80 °C for 25 days. After 253 cycles of heating and cooling between 10 and 70 °C, the PCM-LRPU composite foams exhibited 213.8 and 205.8 J/g as stored and released energy, respectively. The compressive strength of PCM-LRPU composite foams was found to be 1460 kPa at 10% strain, which outperformed the required compressive strength of polyurethane insulation in structural panels. The thermal profile analysis of PCM-LRPU foams as a modelbuilding envelope confirmed the excellent thermal performance of the hybrid composite foams, which would reduce the temperature fluctuation and peak energy demand of buildings. This rigid, synthetic/natural hybrid composite foam with the cell-wall pores in a closed-cell structure would be useful for shape-stabilized PCM serving not only as thermal energy storage but also as loading-bearing components in buildings.

Development of rigid polyurethane foam incorporating phase change material for a low‐temperature thermal energy storage application

“…Utilizing neicosane as a PCM, lignin-based hybrid PU foam was generated as a shape-stabilized PCM composite with load-bearing and temperature regulation capabilities for use in construction. 43 Even after 250 heat cycles, composite foam still exhibited a melting enthalpy of 213.8 J g −1 and a crystallization enthalpy of 205.8 J g −1 . In order to use less non-renewable resources and to store more energy PU foam made from crude glycerol was converted into an extensible graphite-based PU-MPCM foam.…”

“…The composite had an enthalpy of 25.20 J g −1 at 13.5% MPCM loading, and MPCM microencapsulation efficiency was 91%, the highest value ever recorded for n ‐tetradecane. Utilizing n ‐eicosane as a PCM, lignin‐based hybrid PU foam was generated as a shape‐stabilized PCM composite with load‐bearing and temperature regulation capabilities for use in construction 43 . Even after 250 heat cycles, composite foam still exhibited a melting enthalpy of 213.8 J g −1 and a crystallization enthalpy of 205.8 J g −1 .…”

Polyimide foam composites with nano-boron nitride (BN) and silicon carbide (SiC) for latent heat storage

“…The foam was adhered to the aluminum substrate by using a paraffinic PCM film, PPF [49,50]. Another paraffinic PCMceramic composite film was laid over the foam surface and all the layers were hot-pressed into a paper-like layered composite with latent heat storage capability.…”