Indoor air quality is a crucial factor when evaluating habitability, especially in developed countries, where people spend most of their time indoors. This paper presents a novel double skin façade (DSF) system that combines physical and photocatalytic filtering strategies. The air purification system is made up of fixed slats that are both solar protection and air purification system. The objective of this work is to determine the thermal behaviour of the proposed system, so that its suitability for use in various environments may be assessed. This was carried out using a physical 1:1 scale model and a computational fluid dynamics (CFD) model. The maximum temperature inside the scale model cavity was 17–20 °C higher than outdoor air. Additionally, it was discovered that the airflow through the DSF would require forced ventilation. To determine the emissivity values of the photocatalytic coating, additional experimental measurements were made. The CFD model was tested for summer and winter conditions in Barcelona, Chicago, and Vancouver. The average increase in the intake air temperature was around 14.5 °C in winter and 12 °C in summer, finding that the system has its main use potential in temperate or cold areas with many hours of solar radiation.

Due to the current climate crisis, there is an urgent need to reduce greenhouse gas emissions. Improving façades’ energy performance can significantly reduce the cooling and heating demand of a building. More and more, in warm and mild climates, ventilated façade are given the function of avoiding overheating due to solar radiation and thus reducing the cooling demand of the building. However, this system’s energy performance is not easy to estimate. This study aims to assess the influence of some defining parameters of the ventilated façade on its energy performance. These parameters are not considered in the usual evaluation systems and can be relevant to the envelope’s energy performance. A calculation system has been developed so that architects can use it during the design process to know how their design decisions influence energy performance. Once validated with comparisons with measured values, the calculation system is applied to analyse the influence of some defining parameters of the façade during a warm day in Barcelona: the outer surface’s colour and the dimensions of the ventilation channel. For the studied cases, the change of these parameters implies an important variation in the daily average energy flow traversing the façade. In some cases, it even reverses the direction of the flow, changing from heat gains to heat losses. This concludes that these parameters are relevant to the energy performance of the ventilated façade and that the developed calculation system is a suitable tool to compute it.

Indoor air quality determines the comfort, health, and wellbeing of people in buildings. Windows are the optimal elements for providing natural ventilation and fresh air, but the outside contains suspended particles that can be harmful in high concentrations. This work presents an openable and double-glazed façade component with a cavity that includes a series of slats that filter the air and depurate it by means of a photocatalytic reaction (TiO₂). This component integrates the functions of ventilation, solar protection, and air purification, which were analysed in the slat and the façade component to approve a preliminary design. To this end, it was applied to a specific case, a non-residential building at a latitude 41° N in a Mediterranean climate. The results show the optimal dimensions according to solar radiation and ventilation in this specific case and the method used to obtain them, along with the increase in the temperature of the incoming air with respect to the outside (10 °C). Finally, the results obtained from a photocatalytic coating sample show that the NOx degradation can be up to 9%. All these results confirm the applicability of this component in buildings and pave the way for further research.