Cooling Coil Unit dynamic control of in HVAC system
In this paper, a dynamic Cooling Coil Unit (CCU) model is firstly developed by extending the CCU engineering model [1], and by combining the model with the mass and energy balance equations. Unlike other existing CCU models for dynamic control, this modeling method with only six model parameters is relatively simple and exactly captures the nonlinear characteristics over a wide operating range of CCU without requiring much calibration effort and geometric specification, which is very convenient in real time engineering control practice. Afterward, the nonlinear model of CCU is linearized using Jacobian matrix method and PID-action controller as linear control systems are developed on linear model to adjust the outlet air temperature and outlet chilled water temperature. Experiments on a centralized Heating, Ventilation and Air Conditioning (HVAC) pilot plant are conducted to show that the method is robust and gives an accurate match to real performance over the wide operating conditions.