Focusing on summer setpoint temperature to intensify PCM effectiveness in building: energy saving in Jeddah climate

Considering the 66% share for cooling and 3% for building heating in Saudi Arabia, the effect of PCM on reducing energy consumption by focusing on summer setpoint temperatures (STsummer) was examined. A 2 cm layer of RT-25HC (22-26 degrees C) was added to the wall and ceiling with thermal resistances of 0.723 and 1.057 m(2).K/W. At STsummer=22 degrees C, RT-25HC resulted in an energy saving of 8.12 kWh/m(2). As STsummer increases to 25 degrees C, the energy saving reaches 55.54 kWh/m(2) (maximum value). A further increase in STsummer reduces energy saving to 39.69 kW (at 27 degrees C). In this study, the effects of RT-25HC thickness were also discussed and it was observed that thickness increasing had undesirable results. The presence of RT-25HC increases the thermal resistance, hence reduces the heat exchange, if PCM does not undergo the phase change. If RT-25HC has a phase change, increasing its thickness boots heat transfer which is not advantageous. However, at thickness 3 cm, RT-25HC is still useful, and under the best conditions, energy saving was 41.1 kWh/m(2).