Evaluation of Supply Air Temperature Control Performance with Different Advanced Control Strategies at Air Handling Units

41 Pages Posted: 1 Jul 2023

See all articles by Zufen Wang

Zufen Wang

Tennessee State University

Marwan R. Hashem

University of Oklahoma - School of Aerospace and Mechanical Engineering

Li Song

University of Oklahoma - School of Aerospace and Mechanical Engineering

Gang Wang

University of Miami

Abstract

Due to its nonlinear feature, supply air temperature control systems at air handling units using single-loop fixed gain control frequently suffer unstable response under dynamic conditions. This paper is aimed at identifying a more effective control strategy to stabilize the valve control and achieve desirable supply air temperature response under various operation conditions by evaluating three advanced control strategies, cascade, gain scheduling and cascade plus gain scheduling controls. Firstly, a control-oriented model is developed and calibrated through open-loop tests. Then, the control issues with single-loop fixed gain control are evaluated through simulations and field tests, which indicates that the system has more aggressive response or becomes unstable under lower load conditions when the chilled-water flow rate is less than 0.1 L/s. Finally, three advanced control strategies are proposed and evaluated. The results reveal that all three proposed controls can achieve better robustness with the integral square error of supply air temperature decreased to 16%, 47% and 5%, respectively, under lower load condition. However, since high-frequency oscillation of the control valve occurs with cascade and cascade plus gain scheduling control, the gain scheduling control is recommended considering a trade-off among the supply air temperature response, valve lifetime and implementation complexity.

Keywords: cooling coil valve, supply air temperature, nonlinear, cascade control, gain scheduling

Suggested Citation

Wang, Zufen and Hashem, Marwan R. and Song, Li and Wang, Gang, Evaluation of Supply Air Temperature Control Performance with Different Advanced Control Strategies at Air Handling Units. Available at SSRN: https://ssrn.com/abstract=4487903 or http://dx.doi.org/10.2139/ssrn.4487903

Zufen Wang (Contact Author)

Tennessee State University ( email )

3500 John A Merritt Blvd.
Nashville, TN 37209
United States

Marwan R. Hashem

University of Oklahoma - School of Aerospace and Mechanical Engineering ( email )

Li Song

University of Oklahoma - School of Aerospace and Mechanical Engineering ( email )

Gang Wang

University of Miami ( email )

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