Impact Of Solar Irradiance Data On MPC Performance Of Multizone Buildings

Local solar irradiation data has been used for Model Predictive Control (MPC) in supervisory level building control systems, with significant influence demonstrated on perimeter building zones with a high fraction of window area. This work investigates the impact of uncertain solar estimation on MPC performance with respect to energy consumption and comfort by comparing MPC responses for a multi-zone building based on two solar data sources: measured local Plane of Array (POA) solar data and satellite Global Horizontal Irradiance (GHI) based modeled POA solar data. Hourly solar irradiation on tilted surfaces can be calculated from local or offsite GHI measurements by a common algorithm that includes an empirical correlation to decompose the beam and diffuse components, followed by the application of an anisotropic sky model. Real-time control decisions based on the modeled solar data have been found to violate comfort conditions within zones, particularly if off-site or satellite derived GHI data is employed. The presented case study results inform the value of information, revealing that MPC decisions based on satellite derived solar data cause comfort violations that depend strongly on the building system characteristics, such as HVAC and internal gains.