Microencapsulated phase change materials for enhancing the thermal performance of Portland cement concrete and geopolymer concrete for passive building applications

Abstract

a b s t r a c tConcretes with a high thermal energy storage capacity were fabricated by mixing microencapsulated phase change materials (MPCM) into Portland cement concrete (PCC) and geopolymer concrete (GPC). The effect of MPCM on thermal performance and compressive strength of PCC and GPC were investigated. It was found that the replacement of sand by MPCM resulted in lower thermal conductivity and higher thermal energy storage, while the specific heat capacity of concrete remained practically stable when the phase change material (PCM) was in the liquid or solid phase. Furthermore, the thermal conductivity of GPC as function of MPCM concentration was reduced at a higher rate than that of PCC. The power consumption needed to stabilize a simulated indoor temperature of 23°C was reduced after the addition of MPCM. GPC exhibited better energy saving properties than PCC at the same conditions. A significant loss in compressive strength was observed due to the addition of MPCM to concrete. However, the compressive strength still satisfies the mechanical European regulation (EN 206-1, compressive strength class C20/25) for concrete applications. Finally, MPCM-concrete provided a good thermal stability after subjecting the samples to 100 thermal cycles at high heating/cooling rates.

The role of radical polymerization in the production of thermoregulating microcapsules or polymers from saturated and unsaturated fatty acids

“…In this way, compounds with melting points above 30 °C are usually described for solar passive heating and domestic water heating applications . Contrary, fatty acids with a solid–liquid transition temperature between 20 and 30 °C are useful for building and greenhouse heating systems, depending on the climate requirements . Finally, low melting temperature materials can find applications in cool storage systems …”

The micro‐/nano‐PCMs for thermal energy storage systems: A state of art review

“…The evaluations of micro‐PCMs on cement hydration and pore structure were carried out, and it was ascertained that mechanical properties such as comprehensive strength of cement mortars was strongly dependent on the mechanical properties of micro‐PCMs. Cao et al fabricated the concretes of high TES by mixing the micro‐PCMs of RT‐27 coated with the LDPE‐EVA copolymer shell into portland cement concrete (PCC) and geopolymer concrete (GPC). Figure shows the SEM images of PPC and GPC cements incorporating of micro‐PCMs capsules.…”

“…SEM images of A, PCC without micro‐PCMs, B, PCC containing 3.2 wt.% micro‐PCMs, C, GPC without micro‐PCMs, and D, GPC containing 2.7 wt.% micro‐PCMs . Reused with the permission from Elsevier license number 4444700728610…”

Thermal conductivity of aerated concrete (AC) composites containing micro-encapsulated phase change materials

“…the macroscale pores varies with the content of micro-encapsulated paraffin, with the same trend as the porosity. This means the micro-encapsulated paraffin initially fills into the pores of the concrete, resulting in a decreasing porosity [18]. The further increase of the paraffin content will somehow cause a higher porosity, which also influences the compressive strength with the same trend as bulk density.…”