Modeling and control of a HVAC system

Abstract

This thesis presents the PID Fuzzy Control for nonlinear, MIMO Heating, Ventilating and Air Conditioning (HVAC) Systems which is vital important and a big energy consumption in modern life.

The main object is to maintain the conditioned space temperature and relative humidity, which is the outputs (targets) of PID Fuzzy Control method, at the set-points values for comfortable condition. There are a great deal of factors affecting the performance of a HVAC system and one of them is the cooling loading which is a time varying variable affecting the system dynamics. For building a single-zone HVAC system model, the manipulated inputs for the system are the flow rate of chilled water from the chiller to coil and the circulating air flow rate supplied by the variable speed fan. Firstly, data pairs resulted from simulating in software is used to build a model. Then, based on this single model, a PID fuzzy controller is designed in the light of the results and feedbacks of the outputs. Lastly, the system has fast and good response with disturbance of time-vary cooling loads.