Experimental Validation of a Numerical Model of a Ventilated Façade with Horizontal and Vertical Open Joints

Abstract

Commercial and residential building is one of the four major final energy consumption and end-use sectors. In this sector, cooling loads represent an important part of the energy consumption, and therefore, they must be minimized, improving the energy efficiency of buildings. Ventilated façades are one of the most widely used passive elements that are integrated into buildings, precisely with the aim of reducing these loads. This reduction is due to the airflow induced in the air cavity by the buoyancy forces, when the solar radiation heats the outer layer of the façade. In the open joint ventilated facades (OJVF), ventilation is attained through the open joints between the panels composing the outer layer. Despite the steadily growing research in the characterization of this type of system, few studies combine the numerical modelling of OJVF with experimental results for the assessment of the airflow in the ventilated cavities. This paper experimentally validates a numerical simulation model of an OJVF. Firstly, the façade performance has been experimentally assessed in a laboratory model determining the temperatures in the panels and air gap and measuring the flow field at the gap using particle image velocimetry (PIV) techniques. Secondly, a numerical model has been developed using advanced Computational Fluid Dynamics (CFD) simulation tools. Finally, an experimental validation of the numerical model has been done. Experimental and numerical results are compared in different planes inside the ventilated cavity. The discrete ordinates (DO) radiation model and the k-ε renormalisation group (RNG) turbulence model better adjust the simulated results to the experimental ones.

ANP model for evaluating the performance of adaptive façade systems in complex commercial buildings

“…The eighth high performance criterion is "ventilation" having the priority value of 4.42%. The results are coherent with the recent previous studies (Iommi, 2018;S anchez et al, 2020) supporting the argument that an air gap is created for the adaptive façade module to adjust the energy efficiency, provide a ventilated façade or increase the thickness insulation content if necessary (Iommi, 2018). Ventilated façades are very commonly utilized passive components unified inside to buildings, specifically to minimize these loads.…”

Methodology for Quantifying the Energy Saving Potentials Combining Building Retrofitting, Solar Thermal Energy and Geothermal Resources

“…In the first place, it is necessary to count on the availability of a representative climate data [53] of a locality. Second, it is necessary to know the characteristics of the existing building façades [54], shading devices, air ventilation [55], fenestration types and the user occupancy [56]. The study of the potential of climatic variables helps to identify the group of passive and active techniques that, when coupled, give the best result [57].…”

Desempenho térmico de fachadas ventiladas opacas

“…Ventilated facades are characterized by a ventilated channel between the internal and external layers of the building envelope. A careful design of these systems must consider functional and performance concerns, as well as aesthetic and architectural issues (SÁNCHEZ et al, 2020). There are several studies in the literature related to ventilated facades, especially focusing on: Double-skin Ventilated Facades, Building Integrated Photovoltaic, Trombe and Solar Walls, Facade Solar collectors, as well as some studies on light weight ventilated facades.…”