Coupling Energy and Daylighting Simulation for Complex Fenestration Systems

The goal of this work is to demonstrate the coupling of energy and daylighting simulation for Complex Fenestration Systems (CFS) using TRNSYS, one of the most user-friendly and complete software as regards the dynamic simulation of building systems. We wrote a custom TRNSYS building block, called Type, in C++ that performs the three-phase method using Radiance. The novel Type denominated Type_DLT exchanges data at every time step with the TRNSYS multi-zone building model known as Type 56. The connection between the two Types occurs through a set of equations that control the CFS based on the amount of exterior and interior daylight, solar gains and internal gains. The Bidirectional Scattering Distribution Function (BSDF) data has to be provided for each state of the CFS. The tool can be used to investigate how different controls of the CFS and occupant behaviors affect thermal and visual comfort and energy savings. We demonstrated the tool on a single zone model taken from a refurbishment project of a shopping mall in Genoa, Italy, developed within the European FP7 project CommONEnergy. The large west facade of the mall is fully glazed. Double-pane windows and venetian blinds compose the CFS. The venetian blinds take a series of states between completely open and completely shut at 60° tilt angle.