This study is the first to numerically evaluate the thermal performance of MPCM-enhanced autoclaved aerated concrete (AAC) bricks combined with an auxiliary heater plate for passive space heating in cold and freezing climates. A two-dimensional finite-volume CFD model with time-dependent outdoor boundary conditions and an apparent-heat-capacity formulation for phase change is developed and implemented in a custom C++ solver. The effects of MPCM volume fraction (φ = 0, 4, 8, 12%) and heater-plate heat flux (q″ hp = 0, 50, 100, 150 W/m 2) are examined over a 24 h cycle with outdoor temperature varying between −15 and 15 °C. Indoor surface temperature (T is), indoor heat flux (q is), MPCM melting fraction (MF), and daily power consumption (DPC) are employed as performance indicators. For q″ = 100–150 W/m 2, φ = 8–12% reduces peak T is by about 1–2 °C and peak q is by roughly 15–25%, while raising minimum values and delaying the peak by 1 h. At these heater powers, DPC drops from about 0. 31–0. 34 kWh/m 2 for plain AAC to 0. 24–0. 28 kWh/m 2 (0–30% saving) with MPCM, demonstrating the potential of the proposed AAC–MPCM–heater configuration for peak-load mitigation and energy-efficient envelope design in cold climates. Moreover, over a 40-year service life, the techno-economic analysis shows that 4 vol% MCPCM delivers the highest returns, with NPV = 11, 689–15, 970 and IRR = 13. 55–17. 45% across q’'=0–150 W/m 2.
Naif Albelwi (Wed,) studied this question.