Modelling and simulation of smart building facades integrating Concentrating Photovoltaic/Thermal Glazing systems

This paper focuses on the energy performance of smart building façades integrating a novel Concentrating Photovoltaic/Thermal Glazing (CoPVTG) technology. This novel façade technology combines glazing based solar concentrating elements coupled with a PV/Thermal absorber. Specifically, the technology consists of a double-glazing panel, the outside pane is shaped into a series of concentrating lens where a thin layer of PV cells is placed at the focus. Heat is recovered from the back of the PV strings by means of forced air flowing through the cavity, and finally used for space heating or pre-heating purposes. So, while insulating the building thermally, the system can provide solar generated electricity and thermal energy (i.e. recovered air flowing through the cavity of PV/T absorber). With the aim of investigating the passive and active effects due to the integration of this technology in the building façade, a simulation model is developed and implemented in a building energy performance tool, developed in-house and called DETECt. The system, being a multi-functional component, contributes to the electrical and thermal needs of the building, while reducing its heating and cooling needs. Thus, to investigate the potentials of the innovative façade and the developed numerical model, a case study relative to a multi-floor high rise office building, located in several European climate zones, is carried out. A comparative analysis with conventional and semi-transparent PV windows is also conducted. Simulation results show that by using the novel façade system, interesting energy savings can be obtained: the innovative system leads to a remarkable reduction of the final energy consumptions, ranging from 30 to 60% for the investigated weather zones, also toward the nearly or net positive zero energy building goal.