Fenestration in the Tropics
Fenestration in the Tropics
One of the biggest challenges a building owner face in the tropics is the cost of keeping a building cool and comfortable for its occupants. The building façade or envelope is the first line of defence against the external elements, and according to the Solar Energy Research Institute of Singapore (SERIS), it accounts for almost 50% of the thermal loads in buildings in tropical regions.
Heat Gain through the Fenestration System
In Singapore, double glazing with low emissivity (low-E) coating are commonly used in commercial buildings, which allow for a reduction in heat gain through the glazing. From the thermal image taken with a FLIR thermal camera shown in Figure 1, we can observe that the glazing areas are in yellow, green or blue in color. This suggests that the glazed area is relatively cool with little heat gain through this region.
Fig 1: Image captured with FLIR Thermal Imaging Camera
However, we tend to neglect other key fenestration components such as the aluminium frames, which typically remain un-insulated and cause large amounts of heat to transmit indoors.
From the thermal image shown in Figure 1, we can see that there is still a source of heat gain into the indoor environment, highlighted by the red region, which is the framing of the façade. Hence, thermal performance of the fenestration system is not optimized, leading to significant heat gain through the framing member. This may result in energy inefficiencies as a larger amount of energy is required to cool the building down. In addition, it may also lead to discomfort for building occupants.
Addressing Heat Gain in the Fenestration Systems
To design a holistic high-performance fenestration system, it is important to ensure that all fenestration components are effectively addressed.
As a rule of thumb, the thermal performance of the fenestration system can be improved in the following sequence shown in Figure 2.
Fig 2: Recommended sequence for improving fenestration system thermal performance
This is because the glazing takes up the largest area in the fenestration system, hence a small improvement in the performance of the glazing will lead to a significant improvement in the overall thermal performance. After the glazing is optimized, heat will enter through the next weakest link, which is the aluminium frame. Following the same logic, after the performance of the frame is optimized, heat will then enter through the next weakest link – the edge of glass.
In a well-designed energy saving fenestration, all 3 components should be adequately addressed, such that there is no significant thermal bridging through any of the components within the fenestration system.
While double glazing low emissivity glazing help address heat gain through the glass, Thermal Break technology can be used to address heat gain through the aluminium frames, which typically represent 10% - 30% of the total fenestration area. Aluminium, a good conductor of heat, has a material thermal conductivity of 160W/mK, which is 160 times more conductive than glass.
Fig 3: Thermal Break technology
By using a thermal break, the interior and exterior aluminium sections can be separated, substantially reducing the heat gain through the fenestration frames and ensuring better indoor thermal comfort. Technoform Thermal Break is made of glass-fibre reinforced polyamide, an engineering plastic with:
- Low thermal conductivity (~533 times lower than aluminum)
- Excellent mechanical properties
After the performance of the frame is optimized, heat will then enter through the next weakest link, which is the edge of glass. To effectively address heat gain through the glazing edge, we can effectively tap on Warm Edge Spacer technology.
Fig 4: Double Glazed Unit with Technoform Warm Edge Spacer
Typically, double glazed units are separated by aluminium spacers, which have high thermal conductivity. However, Technoform Warm Edge Spacer, which is a thermally improved spacer, is made of polypropylene and stainless steel, allowing it to substantially reduce heat transfer at the edge of glazing. The linear thermal transmittance of Technoform thermally improved spacer is almost 2 times better than traditional aluminium spacer.
Driving sustainability efforts in the Built Environment
Designing for high-performance façade systems can significantly enhance building energy efficiency and improve carbon footprint of buildings. Over the past 52 years, Technoform has partnered with built environment stakeholders to continually improve thermal performance of building envelopes. Through these meaningful partnerships, we have successfully implemented high performance façade systems across residential and commercial projects across the world. To date, our thermal insulation solutions have helped to save approximately 119 billion kWh of energy per annum, which is equivalent to 2.16 billion trees saved annually.
In addition, we adopt the whole life carbon approach and strive to address the issue of embodied carbon emissions by consistently reviewing our processes for carbon reduction opportunities. We have recently become a signatory of the Singapore Built Environment Embodied Carbon Pledge, an initiative by the Singapore Green Building Council (SGBC), to pledge our commitment in taking actions to address embodied carbon emissions.
At Technoform, ensuring sustainability is at the heart of what we do. Let us work together to create a greener built environment by designing for high performance facade!
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