Describing HVAC controls in IFC - Method and application

This paper describes a method to overcome current limitations in BIM software to design Building Automation and Control Systems (BACS) functions of Heating Ventilation and Air Conditioning (HVAC) systems through the extension of the IFC-files with information on control functions. The method is illustrated with the description of control functions for a use case including a boiler, a thermal storage, an air handling unit and a floor heating system modelled with a widely used BIM software tool. The focus is set on the description of three simple control functions: the definition of a heating curve, the setup of time schedules for the air handling unit and the flow temperature control for the heating circuit. The proposed method is based on available software tools linked together and enables adding complementary information on controls into the IFC-file, checking it for consistency, extracting and converting the IFC content into a linked data format. The use of semantic web technology allows for interoperability with various applications like e.g. software used for the commissioning or the supervision of HVAC systems and thus can contribute to reduce current quality and performance deficits of these systems.