Development of a modeling strategy for adaptive multifunctional solar energy building envelope systems

To achieve significant progress towards global targets for clean on-site energy self-sufficiency within the building sector, the integration of adaptive high efficiency solar collection systems into building envelope systems could offer broad additional benefits beyond power generation, such as: daylighting, hot water heating and purification, thermal comfort control, energy use reduction through lowered lighting and cooling loads, and tie-ins to direct current (DC) microgrids. Dramatic system efficiencies could be achieved with multifunctional envelopes by coupling to building systems to respond to fluctuations in weather and building use patterns. The development of active building envelope systems is impeded by current modeling workflows which do not provide adequate feedback or facilitate rapid design iteration within the context of building energy modeling (BEM). A simulation environment, Modelica, has purported extensibility and ease of co-simulation through the functional mock-up (FMI) standard. This environment is evaluated here through the development of a model for a novel multifunctional building envelope system, with concentrating photovoltaic and thermal collectors (BITCOPT) that incorporates multiple active and passive energy strategies simultaneously, while providing architectural benefits such as increased transparency and connection to views. The model is calibrated with measured data from an experimental prototype and is used to extrapolate the system's theoretical power generation and energy efficiency effects. The simulation environment did indeed facilitate extensible model construction, encouraging future work to be pursued in co-simulation of the model with BEM via the FMI standard. The model structure, correlation to measured data, extrapolated results and future work are described here.