Investigation into energy performance of a school building in a hot climate: Optimum of window-to-wall ratio

Abstract

Global attention is currently focussed on developing techniques to improve the thermal performance of buildings to provide indoor comfort with minimum reliance on energy load. Several studies have investigated building facade, materials used and other factors involved in building design. The aim of this study is to examine the impact of thermal insulation, shading devices, window-to-wall ratio (WWR) and a combination of these factors in a prototype school building design in the warm climate city of Taif, Saudi Arabia. The study used various methods classified into two main phases. The first phase involved on-site observation where both thermal imaging and regular cameras were used to examine the influence of orientation on glazing as a baseline. The second phase involved advanced software investigations with 2D AutoCAD, 3D Revit and computer modelling for energy evaluation and daylight factor. A detailed framework was introduced to examine current school buildings and to improve the future designs of prototype school buildings. The study revealed that a combination of applying thermal insulation along with minimising WWR is required in existing buildings within hot and dry regions. Furthermore, it was recommended that WWR should not exceed 35%, 25% and 20% for northwest, southeast and southwest building facades, respectively.

User Thermal Comfort in Historic Buildings: Evaluation of the Potential of Thermal Mass, Orientation, Evaporative Cooling and Ventilation

“…Thus, each direction would have a different WWR depending on the local climate (Figure 2 shows different climatic zones in Saudi Arabia), which is very similar to the findings of Alwetaishi [11], where each direction within the same building was designed according to the diversity of the solar radiation exposed to the outer surface of each direction. The study revealed that the south and west orientations should have their glazing minimised as compared to the east and north ones.…”

“…However, the amount of cooling energy generated by the increase in the WWR was greater than that of the energy saved in winter, which led to the overall increase in the annual energy consumption. Even in cold climate, there is a significant influence of windows in the form of solar heat gain [11].…”

“…Some of the thermal elements were calculated on the basis of the building material of the Palace (Table 4), such as the solar heat gain, which was affected by the WWR and the type of glazing. It is very important to address the size and type of glazing in buildings in such a region [11]. In addition to this is the building heat transfer, which is affected by the type and the width of the building envelope.…”

The Effect of Window-to-Wall Ratio (WWR) and Window Orientation (WO) on the Thermal Performance: A preliminary overview

“…From another angle for a similar climate, (Alghoul et al, 2017) noted that S, SE and SW of windows are the highest in cooling energy consumption. In education building, (Alwetaishi & Taki, 2020) suggested that the WWR for classrooms facing SW and SE should not exceed 20% and 25%, respectively. Conversely, NW classrooms can have up to 35% WWR in hot climates.…”

Influence of the Adaptation of Balconies to Loggias on the Lighting Climate inside an Apartment Building under Cloudy Sky

“…The brightness of the sky at the zenith is always higher than the brightness on the horizon. In the case of winter cloudy skies with dark terrain, this difference is threefold [32]. It follows from these facts that placing the balcony structure above the window opening means that the brightest part of the sky will be shaded and thus the largest source of daylight will be shaded.…”