Login | Register

PI-control in dual duct systems : a study on manual tuning and control loop interaction


PI-control in dual duct systems : a study on manual tuning and control loop interaction

Jetté, Isabelle (1997) PI-control in dual duct systems : a study on manual tuning and control loop interaction. Masters thesis, Concordia University.

Text (application/pdf)


Good HVAC control schemes in buildings help reduce energy use and maintain occupant comfort. PID controllers are widely used in commercial buildings to keep variables such as temperature, pressure and humidity at predefined setpoints. These controllers, when they do not include autotuners, must be carefully tuned. Also, one must consider the effect of interactions occurring among the control loops during the fine-tuning stage so one loop response is not improved to the detriment of another. This research emphasizes PI-control of dual duct systems. Three tuning methods (Ziegler and Nichols' sensitivity method, simplified IMC-PID method, and Bekker et al. method) were selected and tested on a small scale dual duct system with four decentralized control loops (cooling valve, fan speed, damper and heater). Each controller was tuned according to the best performing set of tuning parameters and the system was then operated under design conditions to observe the interactions among the control loops. Since interaction was minimum, a better understanding of interaction was obtained by introducing a sustained oscillation in each loop, one loop at a time. An oversensitive valve was found to have a severe effect on damper control loop and an oversensitive damper was found to interact with fan speed control. Considering these interaction effects, two sets of optimizing curves were developed for the dual duct system. The use of these curves improved some loop responses without rendering other loops unstable

Divisions:Concordia University > Gina Cody School of Engineering and Computer Science > Building, Civil and Environmental Engineering
Item Type:Thesis (Masters)
Authors:Jetté, Isabelle
Pagination:xiv, 164 leaves ; 29 cm.
Institution:Concordia University
Degree Name:M.A. Sc.
Program:Building, Civil and Environmental Engineering
Thesis Supervisor(s):Zaheeruddin, Mohammed
ID Code:203
Deposited By: Concordia University Library
Deposited On:27 Aug 2009 17:10
Last Modified:18 Jan 2018 17:13
Related URLs:
All items in Spectrum are protected by copyright, with all rights reserved. The use of items is governed by Spectrum's terms of access.

Repository Staff Only: item control page

Downloads per month over past year

Back to top Back to top