Robust adaptive fault estimation for multizone building VAV terminal units

In this paper, we propose a novel bilinear observer- based robust fault detection, isolation and adaptive fault estimation methodology to precisely estimate a class of actuator faults, namely bias in damper position and lock-in-place faults, in Variable-Air-Volume (VAV) terminal units of Heating Ventilation and Air-Conditioning (HVAC) systems. The proposed adaptive fault estimator is robust in the sense that the fault estimates are not affected by the unmeasured disturbance variable and that the effects of measurement noises on fault estimates are attenuated. The fault estimation algorithm with the integrated building control system improves occupants comfort and reduces the operation, maintenance, and utility cost, thereby reducing the impact on the environment. The effectiveness of the methodology for adaptive estimation of multiple or single VAV damper faults is successfully demonstrated through different simulation scenarios with SIMBAD (SIMulator of Building And Devices), which is being used in industries for testing and validation of building energy management systems.

Robust adaptive fault estimation for multizone building VAV terminal units

In this paper, we propose a novel bilinear observer- based robust fault detection, isolation and adaptive fault estimation methodology to precisely estimate a class of actuator faults, namely bias in damper position and lock-in-place faults, in Variable-Air-Volume (VAV) terminal units of Heating Ventilation and Air-Conditioning (HVAC) systems. The proposed adaptive fault estimator is robust in the sense that the fault estimates are not affected by the unmeasured disturbance variable and that the effects of measurement noises on fault estimates are attenuated. The fault estimation algorithm with the integrated building control system improves occupants comfort and reduces the operation, maintenance, and utility cost, thereby reducing the impact on the environment. The effectiveness of the methodology for adaptive estimation of multiple or single VAV damper faults is successfully demonstrated through different simulation scenarios with SIMBAD (SIMulator of Building And Devices), which is being used in industries for testing and validation of building energy management systems.

Pressure Loss Coefficients for VAV Terminal Units

This study utilizes static pressure drop data taken from one manufacturer’s catalog to develop total pressure loss coefficient correlations for single duct VAV terminal units having a circular inlet duct and a rectangular outlet. The control dampers for each box were assumed to be in their wide open position. Separate correlations are presented for cases including a plain box, as well as terminal units that have either hot water reheat coils consisting of one to four tube rows, or an electrical heating element. In every instance the correlations account for static pressure and velocity pressure changes between the box inlet and outlet, based on cross section changes. The correlations are useful for duct designers, since they facilitate the utilization of numerical duct design approaches that require extensive iterative calculations, such as the static regain method. The correlations are proposed for inclusion in duct fitting loss coefficient databases.