Search Results (4)

Highly glazed spaces are visually appealing and trendy, but effectively managing their temperature in hot arid climates remains a significant challenge. This study evaluates the effectiveness of dark-tinted double low-E glass with internal roller blinds in reducing heat gain in glazed spaces in hot arid climates and investigates architects’ perspectives on these facades. It combines field measurements and a survey to assess the balance between thermal control and aesthetics in such environments. This study reveals that the current glazing significantly attenuates solar radiation ingress, evidenced by a marked indoor-–outdoor temperature differential (ΔT) of approximately 9.2 °C. The mean radiant temperature registers at 1.5 °C above the indoor air temperature, which can be attributed to the glazing’s propensity to absorb and retain solar heat, resulting in an inner glass surface temperature of 43 °C. The implementation of adjustable blinds has a dynamic influence on the heat transfer coefficient (HTC), effectively modulating the temperature by impeding natural convection currents. With the blinds retracted, the HTC stands at an average of 7.1 W/m²K, which diminishes to 5 W/m²K when the blinds are 50% closed and further reduces to 4.2 W/m²K when the blinds are fully closed (100%). Survey results suggest that architects prioritise glazed facades for aesthetics (52%) while facing challenges in thermal and energy efficiency (44%). Future studies should concentrate on developing novel glazing systems that integrate solutions for visual appeal, lighting and thermal efficiency in glazed facades, particularly in hot arid climates. Full article

With the prevalent use of large glazings, particularly in office buildings, offices receive an abundance of light and are among the largest consumers of electricity. Moreover, in an extreme hot arid climate such as in the UAE, achieving comfortable daylighting levels without increasing solar heat gain is a challenge, in which the window or fenestration design plays an essential role. This research adopts a case study of a higher education (HE) office building on the United Arab Emirates University (UAEU) campus, selected to investigate an evidence-based retrofitting solution for the west façade that can be applied in existing office buildings in the UAE in order to reduce cooling energy load as well as enhance indoor environmental quality. To achieve an evidence-based retrofitting solution, the research design built upon a comprehensive exploratory investigation that included indoor environmental quality physical monitoring and occupant satisfaction surveying. Model simulation was performed by means of DesignBuilder software to perform a single- and multiparameter sensitivity analysis for three key passive window design parameters, i.e., window-to-wall ratio, glazing type, and external shading, aimed towards minimizing annual cooling load and solar heat gain, while maintaining appropriate indoor daylight illuminance levels. The results highlight the importance of the window-to-wall ratio (WWR), as it is the single most significant parameter effecting total energy consumption and daylighting levels. The results recommend 20–30% WWR as the optimum range in the west façade. However, by utilizing high performance glazing types and external shading, equal energy savings can be achieved with a larger WWR. Double Low E tinted glazing and 0.4 projection shading overhang and side fin revealed a noteworthy reduction of energy use intensity of 14%. The study concludes with final retrofitting solutions and design recommendations that aim to contribute validated knowledge towards enhancing window performance in a hot arid climate to guide architects and stakeholders to apply a range of passive parameters towards reducing energy consumption and improving occupant comfort in office buildings. Full article

In Saudi Arabia, residential buildings are one of the major contributors to total energy consumption. Even though there are abundant natural resources, it is somewhat difficult to apply them to building designs, as design variables, due to slow progress and private issues in Saudi Arabia. Thus, the present study demonstrated the development of sustainable residential building design by examining the daylighting and energy performance with design variables. Focusing on the daylighting system, the design variables were chosen, including window-to-wall ratios (WWR), external shading devices, and types of glazing. The illuminance level by these design variables in a building was evaluated by using daylight metrics, such as spatial daylight autonomy and annual sunlight exposure. Moreover, the building energy consumption with these design variables was analyzed by using energy simulation. As a result, the daylighting was improved with the increase in WWRs and the tinted double glazing, while these design options can cause overheating in a residential building. Among types of glazing, the double pane windows with a low-E coating showed better energy performance. Based on the results, it is necessary to find the proper design variables that can balance the daylighting and energy performance in residential buildings in hot climates. Full article

This paper investigates the effect of an existing façade’s construction (viz. clear/grey/solar film, with and without external shade) and orientation on the performance of low-e (hard coat)-based retrofit double glazing in a tropical climate. The performance of double-glazed façades is characterized by the ability to reduce solar heat gain and the consequent reduction in power consumption of air-conditioning systems. This study involves a real-life test-bedding of a low-e (hard coat)-based retrofit double-glazing façade for a few specific cases—clear glass southeast façade without shade, clear glass southwest façade with external shade, and northwest façade with solar film and external shade. Subsequently, energy modelling simulations were done to analyze other scenarios involving various combinations of façade orientation (north, south, west, and east) and façade material (clear glass, tinted grey glass, clear glass with solar film) with and without external sunshades. The east/west-facing façades had a higher impact on the retrofit solution, and more so when the existing façade was of tinted glass or with solar film. For the case analyzed, with a window-to-wall ratio of 8% (based on overall building envelope), a grey tinted east-facing façade could benefit from annual average HVAC energy savings of up to 5.9%. Full article