Towards Automated HVAC Controls Commissioning: Mechanisms to Identify Temperature and Flow Related Functions of AHU Components

Commissioning (Cx) of heating, ventilating, air conditioning (HVAC) systems has emerged as an effective sustainable practice to ensure high performance of these systems during operation. According to a DOE report, HVAC systems used 62% of the energy consumed by buildings in the US in 2011. It was also reported that controls related issues resulted in wastage of 50% of the HVAC energy consumption in 2011 (around 10% of total building energy consumption). Incorrect implementation of controls is a very common issue that can be traced back to improper representation of design intent of controls in the sequence of operations (SOOs). SOOs are currently represented through textual narratives that cannot be completely and accurately interpreted for comparison against the implemented controls during Cx. As a result, incorrectly implemented controls may remain undiagnosed, resulting in inefficient operation, energy wastage or both. Currently, there is no guideline that can be used to identify the information to be included in SOOs. ASHRAE GPC 36 provides SOOs for 13 AHUs and ASHRAE Guideline 13 provide one sample SOOs, but they both do not list specific information to be included in SOOs. OpenBuildingControl is a research project to automatically implement the SOOs from ASHRAE GPC36 and simulate them through Spawn of EnergyPlus (SOEP) simulation engine. Even with all these efforts, there is still a need for a generalizable approach for identifying the information to be included SOOs for any AHU configuration, including the ones not included in ASHRAE GPC36. This paper describes a generalized way of identifying information items to be listed in SOOs. This approach incorporates functional and topological reasoning mechanisms to identify all temperature and flow related control processes within an air handling unit (AHU) and all components that influence each control process in a generalized way, regardless of the configuration of specific AHU.