Intelligent controllers design based on electronic temperature controllers for large central air-conditioning systems

To avoid some unnecessary energy waste of the central air-conditioning system automatically, a design of intelligent controllers and the related control algorithm are proposed to close fan coils at certain times of the day. As many temperature controllers are not qualified with timing function, the timing function is added to temperature controllers by this method without replacing the original devices. The intelligent controller can check the on/off state of fan coil units at set times. If some fan coil unit is found in “on” state at the set time, the fan coil unit will be shut down. Air conditioners will not be left “on” because of human negligence by setting the closed time. According to the result of experimental tests, the design and control algorithm can meet requirements of daily use.