## 5 Studies on Using other Types of PMC in Concrete for Thermal Energy Storage
According to the simulations, efficiency improves with increasing oil mass flow and time, eventually reaching an asymptotic value. To avoid the leaking of PCMs, [PERSON] et al. (2020) [PERSON] et al. (2020) created an encapsulated thermal storage aggregate (ETSA) by mixing PCMs with ceramic or pumice and coating the mixture with a multi-layer shell. The results suggested that ETESC is acceptable to be used as thermal insulation construction covers, even when ETSA totally replaced regular lightweight particles in the concrete. The ETESC's compressive strength was more than 5 MPa. The greatest increase in heat conductivity with ETSA included was 15.8% when compared to the control lightweight aggregate concrete. Furthermore, the electric thermal storage performance findings showed that the maximum temperature decrease of the centre point in the room model supplied with ceramsite-based ETESC reached 4.7 \({}^{\circ}\)C, while the maximum temperature reduction of the centre point in the room model provided with pumice-based ETESC reached 8.7 \({}^{\circ}\)C.  
Figure 10: (**a**) Thermal response of 50% NT-A/OP3E/CC mortar and (**b**) Heat flow vs. mortar temperature [PERSON] et al. (2020). The properties of lightweight concrete made from highly porous aggregates impregnated with PCM were studied by [PERSON] et al. (2020) [89]. Autoclaved aerated concrete (ACC) production byproducts were utilised as aggregates in this application. Paraffinic carbon microspheres (PCM) were employed to impregnate the blocks at a weight of around 65%. By volume, from 25 to 100 percent, the non-PCM aggregates were switched out for PCM aggregates. The results revealed that when the percentage of PCM aggregate was raised, the density, compressive strength, and flexural strength all improved. As PCM aggregates increase, so does their thermal conductivity. However, it was shown that when PCM aggregates were increased, the loss of sound transmission decreased. An investigational examination of PCMs integrated into layers inside a concrete block for thermal management was given by [PERSON] et al. (2020) [90]. Two identical concrete building blocks were created, and the thermal performance of each was compared under natural conditions with and without PCM incorporation. Analysis of temperature changes reveals that PCM-integrated concrete blocks are more stable than those without PCM. The results show that the concrete block treated with PCM has a maximum air temperature that is 3 \({}^{\circ}\)C lower than the control block. The temperature profile within the concrete block is also smoothed out once PCM is added. Figure 11 depicts the results of an analysis of the impact of varied PCM thickness, which show that a thickness of 12 mm is optimal for the used concrete block space. [PERSON] et al. (2020) [91] attempted to use a combination of Ground-Granulated Blast Furnace Slag (GGBS), superplasticizers as cement alternatives, and fly ash. After PCM and nanomaterials were added to the cement concrete at several concentrations (from 0% to 20% in 5% increments), the mixing procedure was improved. A typical compressive strength of 20 MPa was attained by the as-prepared composite, attesting to its structural stability. The experimental findings also show that the PCN-PCM composite has a high latent heat potential, allowing it to store thermal energy and maintain a constant 24 \({}^{\circ}\)C in the test room's air. To protect concrete from premature frost damage at subzero temperatures, [PERSON] et al. (2020) [92] created a new synthetic heat storage form, including PCMs (SHSPCM). Continuous curing of concrete was achieved by using electric heating connected inside to provide PCMs with enough heat energy to cause a phase shift repeatedly. PCMs have a large amount of latent heat, which was put to good use. Concrete cured using this innovative heat storage technology obtained good mechanical strength and hastened hydration at a temperature of \(-15\,^{\circ}\)C, according to the findings of curing experiments.