An embedded control system for AC motor drive to reduce energy consumption of evaporative coolers

This paper presents a new method for controlling and saving electrical energy in evaporative coolers. For this purpose, a variable-speed drive is used to control the electric motor of the evaporative cooler. In this study, first, the thermal equations of the evaporative cooler and its surroundings are presented, analyzed and simulated. Then the existing motors and appropriate design range for their rotor speed control are identified. The control approach is based on a modified proportional-integral control with a variable optimal temperature set point. The performance of the method used is validated by experimental measurements and data collected from an evaporative cooler equipped with the embedded control system. It can be concluded that the implementation of an embedded control system for the evaporative cooler can reduce energy consumption by 44.6%.