Adopting PCM and natural ventilation in buildings to reduce energy demand in HVAC -Examining various PCM along with various natural ventilation scenarios

In hot and desert regions, the daily variations in ambient temperature. In these areas, natural ventilation can be used to fall the indoor temperature. In this study, the effect of natural ventilation was investigated for a building that used PCM to reduce the indoor temperature. In three hot and desert geographical locations, four cases were introduced, and the building power usage (BPU) was analyzed numerically. In case I, mechanical ventilation was utilized to meet the needed oxygen requirements. In other cases, in addition to mechanical ventilation, natural ventilation was also utilized. Ventilation in the second case was active when the outside was cooler than the inside. In case III, a more extra limit was imposed so that natural ventilation would be cut off if the outside temperature was below 15 °C. In case IV, an indoor temperature limit of more than 15 °C was applied. The results for all three regions showed that ventilation declined BPU. Case II showed the largest decrease in BPU within 2.5–11.25% depending on the climate conditions. But since there was no limit to the minimum temperature of fresh air, this method may make the indoor space unfavorable in winter. In the Riyadh region, case II dropped indoor temperature below 10 °C . The third case, which was more stringent scenarios, in all three areas, in addition to reducing the BPU in the range of 2.5–7.95%, also kept the indoor temperature in the comfort range. • Using natural ventilation to fall the indoor temperature in the presence of PCM was examined. • In three hot-arid zones, four scenarios were introduced and building power usage (BPU) was analyzed. • PCM was added to the roof and walls in a thickness of 10 cm. • Considering the comfort condition, BPU in PCM filled buildings reduced in the range of 2.5–7.95%.