Modelling and control of heating, ventilation and air conditioning

Abstract

In a thermal or cooling system, one of the ways to identify the effectiveness of the air conditioning system is using the Coefficient of Performance (COP). There are various factors that affects the performance of the air conditioning system. In this report, compared with a conventional air conditioning system, an ejector based air conditioning system is proposed to improve the COP where an oil tank heater is used to simulate the waste heat exhaust of an automobile. A model of the hybrid air conditioning also known as an ejector based air conditioning system is proposed to predict the characteristic of the system, using a simplified method. Experiment results show that there is an improvement in the COP of the hybrid air conditioning system compared to the conventional air conditioning system under different operating conditions. In addition, a PID controller is presented to regulate the condensing pressure to the desired value, where the frequency of the condenser fan is considered as a manipulated variable. Some experiment results are also given to demonstrate the validity of the PID method, which improve the respond time of the system.