## 5 Studies on Using other Types of PMC in Concrete for Thermal Energy Storage
To investigate how PCM and its placement affect the hygothermal behaviour and energy performance of the integrated envelope, four envelope designs were tested experimentally. The findings showed that PCM is useful for postponing the peak temperature of the envelope, decreasing energy consumption, and decreasing the amplitude of temperature and relative humidity (T/RH) fluctuations. It was suggested that the PCM be placed in the centre of the envelope and maintained in a semi-molten condition. The peak temperature was delayed by 70.4%, the T/RH amplitude was lowered by 50%/60%, and energy consumption was reduced by 15.3% compared to the setup without PCM. In 2022, [PERSON] et al. [98] created biosourced PCM hemp concrete and characterised its properties. Vacuum-impregnated CA was included in 53% of the hemp shaves. PCM hemp concrete was made from a shape-stabilised hemp shives/CA composite. DSC and SEM were utilised for characterising the materials' morphology as well as thermophysicalfeatures at each step (from the neat CA to the hemp concrete PCMs) and to compare them to the reference state (hemp concrete without PCMs). The results revealed that the PCM hemp concrete had excellent thermo-regulating ability, with an ultimate period shift of 30 min and a discrepancy in temperature of roughly 4.6 \({}^{\circ}\)C between the reference and PCM hemp concrete. [PERSON] et al. (2023) [99] found that adding PCM to the foam concrete mix enhanced the building envelope's thermal performance. Lightweight expanded vermiculite (EV) was used in the initial development of PCM by impregnating it with capric acid (CA) and ethyl alcohol (EA) in a vacuum. Several composite foam mixtures were made and tested in the lab. The authors generated foam concrete by replacing the fine aggregate (Msand) with varying percentages of EV, CA-EA/EV-based PCM, and PCM with additional nanosilica and coir fibre combinations (PSC). Based on the results of the liquid leakage test, it was determined that PCM with a CA to EV ratio of 55% (wt.) exhibited the highest levels of adsorption and stability. The mechanical, hydration, durability, and thermal properties of PCM-enhanced foam concrete composites were all significantly increased. The greater heat storage capacity of the PSC-5%, as shown by the thermal analysis tests, ultimately leads to higher levels of thermal comfort in buildings. Acid activation, spray drying, and calcination of palygorskite (Pal) as a raw substance were described by [PERSON] et al. (2023) [100] as an efficient technique for manufacturing hierarchical porous composite microspheres (PCN). To create PCN, Pal nanofibers and cellulose nanocrystals were cross-linked in a certain ratio, yielding a spherical, hierarchical, porous structure. The elevated stability of shape, the elevated efficiency of photothermal transformation, and the elevated latent heat storage capability of the Paraffin-PCN (P-PCN) composite PCMs were synthesized. The natural cooling of P-PCN from 35 \({}^{\circ}\)C to 30 \({}^{\circ}\)C preserves heat for almost twice as long as P-Pal. With the P-PCN, the melting enthalpy increased to 130.2 J/g, indicating clear benefits in the thermal management of buildings. The thermal behaviour of PCM layer/capsules made from concrete bricks was experimentally investigated by [PERSON] and [PERSON] (2023) [101] amid the sweltering heat of southern Iraqi summers. One brick (BL) was merged with a PCM layer, another brick (BC) was integrated with PCM capsules, and the third brick (BR) was left naked without PCM for comparison. Bricks' thermal performance was evaluated by measuring their average surface temperature fluctuation reduction as well as the difference between their inner and outer surfaces' temperatures, the time lag between temperature changes, and the decrement factor. In addition, the author looked at how each brick lost some of its mechanical strength over time to demonstrate its usefulness in actual buildings.