A solver-efficient computational fluid dynamic approach for the thermal performance analysis of ventilated façades

The paper deals with the use of Computational Fluid Dynamics (CFD) for the thermal performance analysis and optimisation of prefabricated Timber-Concrete Composite (TCC) ventilated façades. TCC envelopes are composed of an internal insulated timber-frame wall coupled to an external concrete slab, separated by a ventilated air cavity. Such systems join the properties of engineered timber (good seismic behaviour, low thermal conductivity, environmental sustainability, and ease of system integration) with those of concrete (high thermal inertia, excellent durability and fire resistance). There is very limited knowledge on the performance of TCC facades, especially for what concerns their thermal behaviour. For this reason, a TCC ventilated façade located in the north of Italy was monitored over one year, and the results collected were used to calibrate and validate a CFD model. A new solver algorithm was developed to speed up the CFD simulations, allowing up to 45 times faster analysis compared to conventional solvers. Thanks to this improvement, the final model is suitable to be used for time-efficient thermal analysis (a full-day real-time simulation takes approximately 23 minutes), limiting the expensive and time-consuming construction of mock-ups. The CFD model developed is suitable for the thermal performance analysis and optimisation of TCC ventilated facades, but also for generic ventilated facades with external massive cladding, both in the case of new and existing buildings.