Research on Fault Diagnosis of Parts in The Primary Return Air System

Abstract

It is difficult to detect the faults of air valve and CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> sensor in the primary return air system. If not handled in time, the system will be affected. First, we built an experimental platform with 10 fault conditions and 1 fault-free condition. Then we selected 5 parameters to describe the system state when the air valve and CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> sensor fail. It is found that faults can change system's ability to control CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> , energy consumption and operating time. For example, return valve's smaller fault results in 2.86% reduction of fan energy, 19.20% increase of system energy, 24.23% increase of fresh air energy and 44.04% decrease of operating time. CO <inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> sensor's larger fault results in 15.32% increase of fan energy, 25.21% increase of system energy and 27.46% increase of fresh air energy. It also makes fan keep working for a long time. In the end, we developed a fault diagnosis table for parts' fault in the primary return air system.