An Online Filter Clog Rate Signal Detection Mechanism in an Air Conditioning System

Currently, a positive pressure blower or a negative pressure exhaust fan, employed in an air conditioning system, is driven by a constant speed AC motor, resulting in a constant air flow rate and a constant pressure. This paper presents an approach to compensate for the air resistance effect. A motor speed sensor is deployed between a brushless DC motor and a chamber, and the voltage drop across a current source is monitored using a digital voltmeter. Digital signal processing (DSP) is performed on the measured voltage signal using a microcontroller unit (MCU). Users can be notified instantly, once a threshold is reached, to clean up or replace a clogged air filter for energy efficiency improvement.