Three TRNSYS types have been programmed to define the fa? ade energy performance: the PV laminate type, the air channel type and the rear glass type. All the types are dynamically coupled by the TRNSYS sequentially solver: the heat conduction heat sources obtained from the first and third types are transferred to the second type as a Newmann boundary condition. Once the heat transfer coefficients, the mass flow rate and the average wall temperatures are obtained within this type, they are returned back to the first and third type. This is an iterative process which converges each time step. The underlying mathematical and physical models are described in the sections bellow.

1.2. Physical model

Air enters the fa? ade at the bottom opening with an average inlet temperature (f ) which is assumed equal to the uniform exterior air temperature (To ). Hot air exits from the top of the chimney at outlet average temperature (f ). The following heat transfer processes simultaneously happens within the fa? ade: solar radiation absorbed by the ^ lid layers, thermal radiation between the back side of the PV laminate and the rear glass front side, thermal radiation between the external layer of the PV laminate and the sky and heat convection between the exterior, the interior and the fa? ade.