PCM embedded radiant chilled ceiling as a solution to shift the cooling peak load-focusing on solidification process acceleration

Radiant chilled ceilings (RCC) are known as cost-effective cooling methods. In this study, phase change material (PCM) was used to improve RCC, and its thermal analysis under the Tabuk climate in Saudi Arabia was discussed. By creating an air gap inside the roof, RCC integrated PCM. With the creation of an air gap and proper PCM placement, heat exchange from the ceiling declined by 57.6% in an annual analysis and 22.6% from April to the end of October. Acceptable PCM performance is due to phase changes during the day. For PCM to be effective in the daytime, it must be frozen overnight. Three methods were used to accelerate PCM freezing: a nanofluid-filled ground heat exchanger, cool ambient airflow and chilled water. The share of the first method in accelerating PCM solidification was 78.6%, and the percentage of the second and third methods was 16.5%. Although the performance of the cool airflow was not suitable for PCM freezing in the PCM embedded radiant chilled ceiling when the cool airflow enters the interior as ventilation, it can reduce power demand by 26.1% in April and by 25.3% in October, but it was not helpful in July and August.