Uncertainty in the performance validation of HVAC Systems

A first principles based model approach to AHU cooling coil performance validation is presented. The model of correct operation is compared to that observed in the real system. In the scheme, uncertainty in the measurements and the models is evaluated to generate robust thresholds for decision making. The approach describes the design intent by estimating certain model parameters from design data and expert knowledge. The method systematically incorporates the uncertainty in these parameter estimates in the calculation of the system validation threshold. This yields a definite, transparent indication of system performance to a stated level of confidence. The approach is demonstrated on a cooling coil subsystem installed in an air-handling unit serving zones in a real building.