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

Abstract

The literature showed many studies that evaluated a 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 evaluate 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 phase change materials (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) can 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. With combining both architectural design strategies with 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.