PRO01: Heating, Ventilation and Air Conditioning

The Heating, Ventilation and Air Conditioning (HVAC) trainer consists of a plexiglass duct, with a heater in one end and a blower in the other end. The heater is a halogen lamp and the blower is a variable-speed fan. There is a thermistor sensor placed inside the duct to measure the temperature of the chamber and another thermistor sensor outside the chamber to measure the room temperature. The temperature measured at the thermistor inside the chamber is to be controlled using the heater voltage while the fan is ran at a constant speed. Heat is transferred to the thermistor by radiation from the heater and by convection from the air stream. Radiative heat transfer is highly nonlinear and it is therefore difficult to model the system by first principles. As a result, empirical tuning will be used to control the system. This heat transfer plant is very similar to the systems that are used to control wafer temperature in semiconductor manufacturing. There are two experiments: on-off control and PI control. The experiments can be performed independently.