Abstract
Existing shopping centres offer a great opportunity thanks to their retrofit for the reduction of the energy consumption. The partners of the European FP7 CommONEnergy project are developing a modular multifunctional façade for the retrofit of shopping malls, capable to adapt to different climates and to the existing building features both by the presence of movable components and by proper sizing of the fixed ones. In particular, the curtain- wall façade is equipped with a fixed shading system, a photovoltaic panel with a battery feeding the automated openings for natural ventilation. The aim of this work is to define a reliable parametric model for a multi-functional façade system, supporting designers with a set of useful data for the proper design of the façade configuration depending on climate, orientation and building use. Firstly, a reference zone model for the façade has been set; this had to be both representative of the real case and smartly defined for simulation software implementation. Besides the definition of the façade model parameters, all free design variables have been settled as minimum and maximum values, depending on different possible applications and environmental conditions in which the façade could be applied. Inputs for the model have been defined in a parametric matrix and they include facade module size, façade orientation, climate, window typology (thermal transmittance and g-value), distance between the shading lamellas and tilt angle, openable window size. The simulation engine is decoupled: visual comfort and artificial lighting use have been assessed with Radiance, while the façade thermal behaviour is evaluated by means of building energy simulations in TRNSYS, taking into consideration the Radiance results. For each simulated configuration, a set of relevant outputs in the field of Indoor Air Quality, thermal and visual comfort, and energy performance have been chosen. The main considered performance indicators are the long-term percentage of people dissatisfied, the number of hour when CO2 concentration is within the recommended values for each of the categories defined by EN 15251:2007, the illuminance provided by daylight, the energy consumption due to lighting, ventilation, heating and cooling, energy generated by the PV panel. Moreover, all outputs have been collected in a user-friendly database and gathered in a simple tool. The work highlights the role of thermal and daylighting simulation in the design of an adaptive multifunctional façade.