building controls, HVAC, energy efficiency, retrofits
It is well known that building control systems frequently under-perform, leading to wasted energy and poor space conditions for occupants. There are many reasons for this, including insufficient design or commissioning, deterioration of equipment over time, changes in building usage and poor maintenance. Therefore, building control systems are prime candidates for retrofits and upgrades. Such activities, though, can be very challenging in their own right. For example, information regarding the design intent and current control logic may be difficult or impossible to obtain due to lack of documentation, proprietary data and communication formats or unrecorded modifications. In addition, there is a great deal of variability in control system configuration and components, so each potential retrofit activity can become a time-consuming and expensive operation requiring a high level of expertise. To reduce these barriers to implementing building control system retrofits, a method has been developed to assist in the identification and assessment of building control system operation and retrofit potential. The components of the method include a system identification process that categorizes the building by type and usage, then it produces an information model of the control system, which can be compared to other similar buildings by category. Control system requirements to meet two performance levels are provided, namely current best practice and high performance, along with suggested control technology packages to achieve the desired level of performance. This paper describes the method and demonstrates it via a case study.