Comparison of Conventional and Fuzzy Control of Indoor Air Quality in Buildings

This article compares various techniques for the control of indoor air quality in a naturally ventilated building: ON-OFF, proportional-integral-derivative (PID), proportional-integral with deadband (PIdb), and fuzzy control. The control system for the fuzzy controllers is a typical two input (carbon dioxide concentration and its time derivative), one output (change in window opening area) system. Two different fuzzy controllers are modeled: one based on Mamdani's max-min inference, and the other using Gupta's multivariable structure. The results show that the fuzzy controllers and the Pldb controller are much more suitable than the PID or the ON-OFF controllers. The number of cycles of the controlled parameter (i.e., the window opening fluctuations) is actually much smaller. Minor differences between the two fuzzy controllers are observed.