Architectural Design Strategies for Enhancement of Thermal and Energy Performance of PCMs-Embedded Envelope System for an Office Building in a Typical Arid Saharan Climate

The literature showed many studies that evaluated single or multiple Phase change materials (PCMs) layers in passive, active, or in hybrid configurations for building applications. However, little attention has been given to evaluating the energy performance of buildings when PCMs are used together with other passive design strategies. In this work, the energy performance of an office building in a typical arid Saharan climate is simulated using EnergyPlus when a PCMs-embedded envelope is implemented. The office building was analyzed without/with PCMs using various thicknesses. Results indicated that the annual electrical energy for heating, ventilation and air conditioning (HVAC) could be reduced between 3.54% and 6.18%, depending on the PCM thickness. The performance of the office building, including PCMs, was then simulated using two practical architectural design strategies, namely windows-to-wall ratio (WWR) and rezoning of the interior spaces. Outcomes revealed that the annual energy consumption for HVAC can be reduced from 10% to 15.5% and from 6.1% and 8.54% when WWR is reduced by half to three-quarters, and the perimeter zones are enlarged by one-third to two-thirds of the original space area, respectively. By combining both architectural design strategies and PCM, the annual electrical HVAC energy can be reduced between 12.08% and 15.69%, depending on the design configuration and PCM thickness. This design option provides additional benefits also since it reduces the vulnerability of increasing the lighting and fuel gas heating energy because more perimeter zones are exposed to daylighting and solar radiation, respectively.