Modeling fenestration with shading devices in building energy simulation: a practical approach

The use of operable shading devices impacts building loads significantly. The need exists for an explicit treatment of window shading devices in the design of energy efficient buildings through simulation. A general framework for modeling complex fenestration systems has recently been implemented in ESP-r. The underlying models have been developed with emphasis on computational efficiency and straightforward input requirements. The capabilities, which currently include modeling of slat-type blinds in any arrangement between glazing layers, are summarized and an overview of the solar optical and thermal models is given.  An analysis of slat-type blind models was carried out comparing  the complex fenestration facility in ESP-r to slat-type blind models in EnergyPlus. Simulations were conducted for a test cell with a south facing window. The results show good agreement between the two simulation programs. Considering the complicated nature of shading layer modeling, the new complex fenestration facility in ESP-r yielded encouraging results in this preliminary study.