Discrete modeling and control of winter regime of an air conditioning system

Abstract

In this paper, analysis of different control algorithms in HVAC systems is presented. A procedure for deriving a dynamic model of the HVAC system is given. The system consists of an electrical preheater, heat recovery unit, heating coil, three way valve, ductwork, fan and a zone. Mathematical models for the components were derived in continuous and discrete form. Classical and cascade PID controller is used to improve the transient response of the closed loop system. One of the goals of this study is to compare these two different control approaches. Simulations are performed in Matlab Simulink environment for both continuous and discrete case. The results obtained show that the system is capable of rejecting disturbances with small error and within small period of time.