Thermal Performance and Energy Efficiency of Lightweight Steel Buildings: a Case-Study

Abstract

Steel façade systems follow the actual tendencies in construction offering robust and sustainable solutions, able to answer to actual conditions and to offer adequate interior thermal comfort. The modern sandwich panels provided by the current façade system producers combine the required thermal resistance by varying the thermal insulation material and its thickness with the required structural demands. In addition, the façade layer could be over-coated with different materials, thus offering the required architectural aspect. Other advantages of the systems rely on industrialized prefabrication, fast installation and adaptability. They could also be disassembled and reused. The study presents an analysis of some envelope solutions existing on the market for buildings made of thin-walled cold-formed steel structural systems. The study consists in an annual energetic analysis of Mineral Wool (MW)-based system and a more sustainable recycled-PET thermal wadding-system. The analysis includes for input the own-produced energy by power grids and additional national grid energy while for output heating / cooling and electric appliances are considered. The study is completed by a life-cycle environmental analysis. The study revealed that when the thermal insulations have nearly the same U-value, the environmental impact of the recycled-PET thermal wadding-based system is smaller than that of MW-based system. Although the environmental impact of the recycled-PET thermal wadding is higher in the production stage, the insulation quantity of the material needed for PET-recycled thermal wadding to accomplish the required thermal resistance is much smaller than that of MW. Moreover, the original material for the recycled-PET thermal wadding is 100% recycled which implies a certain benefit of circularity to the material. The study also proves that the glazing ratio has also an impact on the thermal performances of studied systems: by reducing the overall glazing ratio of the envelope, the solar gain drops significantly, which leads to an increased heating energy demand, in order to meet indoor thermal comfort.

A Critical Review on Optimization of Cold-Formed Steel Members for Better Structural and Thermal Performances

“…The thermal bridges formed by the accelerated use of steel have motivated many researchers to put efforts into researching in this field, analyzing thermal performance [150,162], and its improvement [163][164][165] or mitigating thermal bridges [48,166], the importance of flanking thermal losses [17], the importance of the size and shape of steel studs on the thermal performance [1], numerical simulations of CFS framed walls [146] and CFS buildings [153], development of analytical methods [156,158] and in situ measurement methods [161,167] to estimate thermal transmittance, comparisons between different methods [156,166], thermal insulation [18,157,168,169], the interaction of thermal and sound insulation [19], and thermal performance and energy efficiency [170][171][172]. Table 2 summarizes the important research works performed over the last two decades on the thermal performance of CFS structures.…”

“…Unlike traditional construction, the thermal performance of CFS buildings is highly dependent on the thermal insulation used in such buildings [16,171]. Roque and Santos [18] showed that the location of thermal insulation in CFS framed facade walls has a huge impact on its thermal performance.…”

Thermo-Energy Performance of Lightweight Steel Framed Constructions: A Case Study

“…Several studies were made to identify the proper materials for the building envelope elements from a holistic design perspective and ease for deconstruction and future reuse of components [26,27]. The chosen thermal insulation is the recycled-PET thermal wadding, fabricated using polyester fibres recycled from post-consumer polyethylene terephthalate (PET) bottles.…”

“…The chosen thermal insulation is the recycled-PET thermal wadding, fabricated using polyester fibres recycled from post-consumer polyethylene terephthalate (PET) bottles. This material has a low environmental impact [22,26], high mechanical resistance, and good physical properties [28]. Another reason for this choice was to stimulate the local economy and the recycling and reuse of materials.…”

“…The solutions were chosen with respect to local sourcing and production of building materials, thus reducing transport emissions and associated costs. 1269 kWh/year (the potential production of the installed polycrystalline cell panels under ideal conditions is 3427.29 kWh/year [26]), and a 1 kW vertical wind turbine. The LSF experimental module includes a monitoring energy management system that offers a solid overview of the building's performance during the operational phase.…”