Modelica Meets ASHRAE: Towards A Digital Standard for Building Control

Abstract

Today's process for designing, specifying, installing andtesting building HVAC control is not digitalized, leadingto expensive manual workflowsand missed operational performance.To digitalize the design-build-operate process for buildingHVAC control, the authors developed a process, associatedtools and initiated the voluntary ASHRAE Standard 231P.This paper describes this process and tools,which are both based on Modelica.Standardization through a proposed voluntary ASHRAE Standardand the existing Modelica Language Specification provides arobust technology foundation for industry investment.It is based on declarative specification of the controllogic,and allows reuse of existing technologies foropen-loop and closed-loop control testing through couplingwith an HVAC system or a whole building energy model. Itsupports control testing using MIL, SIL and HIL,and export of digital twins for operational support.The process and ASHRAE Standard 231P have been designed toaccommodateexisting Building Automation Systems product lines, whilealsoenabling direct code generation such as by using FMI oreFMI.Control deployment can be digital or manual andconformance to the digital specificationcan be tested formally and programmatically at each step ofthe control delivery.