Enhancing indoor thermal comfort in buildings using innovative foam concrete with phase change material

Energy consumption can be reduced by improving thermal performance of buildings and using energy efficiently. This can be achieved by integrating phase change material (PCM) with heat storage properties into foam concretes in building envelopes. The present study aims to prepare diatomite/capric acid (CA) composite, integrate it into foam concrete structure and enhance thermal energy performance of buildings under real weather conditions. For this purpose, it was first determined that diatomite could absorb capric acid at a maximum of 50 % (by weight) without leakage by direct impregnation. The prepared diatomite/CA composite was incorporated to foam concrete mixture as a substitute for sand aggregate at four different ratios of 15 %, 20 %, 25 % and 30 %. For diatomite/CA composite, melting and freezing temperatures and enthalpy values were found to be 28.73 °C and 28.49 °C, and 101 J/g and 193 J/g, respectively. While spreading diameter and dry unit weight values decreased as the ratio of diatomite/CA rose, water absorption and apparent porosity values increased. Thermal conductivity and compressive strength decreased depending on the increase in amount of diatomite/CA. For foam concrete with 30 % diatomite/CA, the highest water absorption, apparent porosity and compressive strength were measured as 25.9 %, 34 % and 6.31 MPa, respectively. Thermal conductivity varied between 0.495 and 0.241 W/mK. Thermoregulation test results demonstrated that foam concrete slabs containing 30 % diatomite/CA significantly improved indoor temperature regulation, achieving a cooling effect of approximately 3.7 °C during peak heat periods and contributing to a heating load reduction at night by maintaining indoor temperatures up to 8.8 °C warmer. • Diatomite was able to absorb up to 50 % CA without leaching. • Compared to reference, diatomite/CA with foam concretes have higher porosity and lower thermal conductivity. • Foam concrete composites exhibited notable performance on indoor temperature regulation. • Foam concretes with PCM are candidates for improving energy efficiency of buildings.