High-performance glazing technologies are essential for achieving the occupant comfort and building energy efficiency required in contemporary and future buildings. In real-world applications, glazing façades are selected from a steadily increasing number of glazing technologies. However, the authors could not identify a systematic and comprehensive review and classification of glazing technologies in the literature. This creates a barrier when comparing typologically different glazing technologies and combining multiple technologies in a glazing unit. This paper provides a systematic review and classification of established and emerging glazing technologies based on publications from 2001–2022 which were interpreted following the PRISMA methodology. This study reveals that the majority of high-performance glazing systems used in practice are in multi-layer glazing configurations and that the glazing system performance can focus on including additional and multiple functionalities, which aim at improving overall building performance. It was also found that there is a large potential for improvement of multilayer, evacuated, aerogels, electrochromic, and solar cell glazing by incorporating other technologies or innovative materials in multi-layer glazing units for either improving existing technologies or for the development of new ones. However, their longevity, robustness, and cost affordability should be ensured.

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As human skin is an important barrier and thermal regulator of the human body, the building "skin" is the first critical element in defining goals for building energy efficiency and Indoor Environmental Quality (IEQ). The glazing part of a building envelope is particularly critical because it is the most vulnerable envelope element to heat gain and heat loss accounting for around 50% of the building’s energy consumption. Increasingly stringent regulations imposed over time mandate the adoption of high-performance façades. In this regard, in the second half of the twentieth century, Double Skin Façades (DSF) were developed. However, with cavity widths varying from 50 cm (1.64 ft) up to 2 m (6.56 ft), DSFs are rather space-consuming and require high installation and maintenance costs. For this purpose, a Closed Cavity Façade (CCF) was developed as a specific DSF system. In its simplest form, a CCF consists of a double or triple glazing unit (DGU or TGU) on the inner layer and single glazing on the outer one, forming a sealed non-ventilated cavity (about 20 cm width) with automated blinds in between which, given its dynamic behaviour, can contribute to balance the demand for energy saving and enhancement of IEQ.

This study, using Energy Plus and IDA ICE building performance simulation tools, investigates the performance of several CCF configurations and geometries, for the eight climate zones of the USA, and compares them to the baseline (a DGU). MATELab, an office-like test facility at the University of Cambridge was used as the model for the simulations, which was beforehand experimentally validated.

The CCF configurations investigated, led to a decrease of energy consumption in the range of 19-44% compared to the conventional DGU used as the baseline. This is mainly attributed to the improved thermal transmittance and solar heat gain coefficient (SHGC) because of integrating Venetian blinds in the cavity. A higher performance improvement is observed in cooling-dominated locations since CCF reduces solar gain through the façade, which is the main contributor to energy consumption. Furthermore, it was shown that suitable selection of the components of a CCF system (such as the colour of blinds and the type of coatings) results in an additional 1-2% improvement of its thermal performance, cutting down overheating phenomena, retaining the glass cavity temperatures below the critical value, and reducing the radiant discomfort providing extra benefits in terms of IEQ and occupant’s productivity.@en

The thermal performance of adaptive building envelopes can be evaluated using building performance simulation tools. Simulation capabilities and accuracy in predicting the dynamic behaviour of adaptive building envelopes can be enhanced through co-simulation. However, it is unclear how accurately co-simulation can predict the performance of adaptive building envelopes and how the accuracy of adaptive building envelope models created in co-simulation setups can be assessed and validated. Therefore, this study presents new evidence on the empirical validation of co-simulation setups for adaptive building envelopes by establishing an assessment framework to determine the extent to which they can accurately represent the real world. The framework was applied to a case study to validate a co-simulation setup for a blind automation system using monitored data from MATELab, a full-scale outdoor test facility with realistic indoor and outdoor conditions. The validation of the co-simulation model of MATELab resulted in a median CV-RMSE index, a measure of model accuracy, of 5.9%. This indicates that the simulated data points have a small variance relative to the measured data points, showing a good model fit. In the future, modellers from the façade community can use the assessment framework for their co-simulation setups.

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In its simplest form, a Closed Cavity Façade (CCF) consists of a double or triple glazing unit (DGU or TGU) on the inner layer and single glazing on the outer one, forming a sealed non-ventilated cavity with an automated shading device in between. Given its dynamic behaviour, this technology can dynamically control the flow of solar energy and light penetrating the building. Using EnergyPlus and IDA ICE, several CCF configurations were investigated and compared to the baseline (TGU). MATELab, an office-like test facility at the University of Cambridge, was used as the model, which was beforehand experimentally validated. The results show extensive benefits of CCFs compared to traditional TGU systems, in terms of thermal performance and occupants’ comfort. The CCF configurations investigated led to an improvement of energy performance in the range of 18–37% compared to the traditional TGU, depending on the CCF configuration and the climate while a previous study, using CCF configurations with DGU as inner skin, revealed an improvement of energy performance in the range of 22–41% compared to the conventional DGU. Further investigation showed that glass coatings and solar shading characteristics play an important role in cutting down overheating phenomenon while increasing occupants’ comfort. Practical application: Governments are making ever more stringent energy regulations for the building industry aiming to reduce energy consumption and carbon emissions. At the same time, building owners and architects are looking at cost-effective solutions for the long-term performance of buildings while tenants/occupants are more than ever aware of the fact that building comfort increases well-being and productivity. In all these regards, this work focuses and accentuates that substantial improvements can be achieved by designing and using suitable configurations of the innovative Closed Cavity Façade according to the climatic conditions of each location. The results presented indicate that there is much potential in improving the energy and comfort performance of a building, raising awareness to help deploy innovative glazing technologies.

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