No abstract

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.

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.

Mathematical modeling of various physical phenomena in general and heat transfer in phase change materials (PCMs) in particular is extremely important, as it allows a deep understanding of the physical laws surrounding latent thermal storage, and on the other hand, generation of models for numerical studies that simulate the experimental protocol with fewer possible errors. On this basis, this work presents a modeling study of a complex wall containing a layer of PCM, without and taking into account the partial phase change hysteresis using the MATLAB environment. A new approach for mathematical modeling of the physical problem was discussed and validated numerically using the dynamic simulation software EnergyPlus. Similar to previous studies, simulation results demonstrated that the phenomenon of phase change hysteresis must be taken into account to more precisely define heat transfer when using PCMs in building structures.