Development of a “cloud” located, Expert Rule based AFDD tool for AHU’s: Field Test Results

Heating Ventilation and Air Conditioning (HVAC) system energy consumption on average accounts for 40% of an industrial sites total energy consumption. Building systems, of which HVAC is one, rarely perform as well in practice as anticipated during design due to improper equipment selection or installation, lack of commissioning, or improper maintenance. AHU operations are typically supervised and maintained by either an onsite facilities team or an offsite third party contractor. The number of AHU’s in a typical large commercial or manufacturing site HVAC system often outnumbers those supervising and maintaining the system by 20 to 1. This means that routine mechanical maintenance is typically carried out only when necessary due to an end user complaint, a machine breakdown or a breached alarm limit. Studies have indicated that 20 – 30% energy savings are achievable by re-commissioning Air Handling Units (AHU) in HVAC systems to rectify faulty operation. Studies have also demonstrated that continuous commissioning of building systems for optimum efficiency can yield savings of an average of over 20% of total energy cost. Automated Fault Detection and Diagnosis (AFDD) is a process concerned with automating the detection of faults and their causes in physical systems. AFDD can be used to assist the commissioning process at multiple stages. This paper details the results of the alpha and beta test phases of a “cloud” located, expert rule based AFDD tool on 26 AHU’s across six large commercial & manufacturing sites yielding over €157,000 of validated annual energy savings detected by the AFDD tool.