Influence of phase change material (PCM) parameters on the thermal performance of lightweight building walls with different thermal resistances

Phase-change materials (PCM) can effectively improve the thermal performance of lightweight building walls (LBW), but their contribution efficiency is related to PCM parameters and the thermal resistance of the original walls (R-wt). Therefore, a heat transfer model of LBW integrated with PCM was built and validated in this paper, and the influence rules and contribution efficiency of PCM parameters on the thermal performance of LBW with different Rwt were analyzed and evaluated by numerical simulation. The results show that: (1) The suitable phase-transition temperature is more influenced by the PCM location and less by R-wt, and the middle of wall and 22-32 degrees C is the best choice for PCM; (2) The PCM parameter values are not proportional to the improvement of thermal performance and its influences are more noticeable as the R-wt decreased, and their optimal values and its contribution efficiency are diminished with R-wt is boosted; (3) The PCM contribution efficiency is reduced by 56.61%(attenuation rate),-34.3% (delay time), 58.31%(peak heat flux) and 61.78%(average heat flux) as the R-wt [(m(2).K)/W] is increased from 2.0 to 5.0 under the suitable PCM parameters. The findings provide data support and theoretical reference for the application of PCM in different types of lightweight buildings.