Comparison of energy consumption in HVAC systems using simple ON-OFF, intelligent ON-OFF and optimal controllers

Abstract

This paper compares 3 different control schemes to regulate temperature and humidity in facilities and compares the energy consumption in each of the cases. The first method is a traditional ON/OFF controller with a dead band region. The second scheme is an intelligent ON/OFF controller where the control system for the heater and humidifier predicts the time the system takes to reach the set point value of temperature and humidity and the energy is supplied to the heater and humidifier based on these predictions. The last controller scheme is an optimal controller where thermal comfort in a building is maintained by tracking a PMV (predicted mean value), which is a function of accepted levels of temperature and humidity from a psychometric chart. In all three cases the energy consumption of the HVAC system is determined and compared. It is observed that the optimal control system to control PMV index in a facility is the best suited choice to regulate thermal comfort. Using optimal control techniques, optimal values of temperature and humidity can be tracked and this leads to maximum energy savings.