Modeling and Nonlinear Control of a Hot-Water-to-Air Heat Exchanger
Abstract
The control of Heating, Ventilation, and Air conditioning (HVAC) systems is difficult due to the nonlinear (open- or closed-loop) nature of the components, the wide range of operating conditions under which they must operate, and the many interactions between them. Accurate models of these component loops can be a great help in evaluating the performance of controllers and control laws, strategies, and tuning techniques. While many models already exist, their accuracy under closed-loop control is very often more limited than under open loop control, due to the change in variables during a closed-loop test. The heat exchanger is such a nonlinear HVAC component. The practice of using linear control on heat exchangers results in sluggish control. This work developed a model for a hot-water-to-air heat exchanger, accurate over a wide range of conditions for both open- and closed-loop simulations. The model was used to develop two nonlinear controls laws, which showed better results than fixed linear controllers. Keywords: Heat exchangers, Automatic control, Hot- water-to-air heat exchangers.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1990
- Accession Number
- ADA228443
Entities
People
- David Underwood
Organizations
- Construction Engineering Research Laboratory