Automatic thermal model identification and distributed optimisation for load shifting in city quarters

ABSTRACT

Buildings with floor heating or thermally activated building structures offer significant potential for shifting the thermal load and thus reduce peak demand for heating or cooling. This potential can be realised with the help of model predictive control (MPC) methods, provided that sufficiently descriptive mathematical models of the thermal characteristics of the individual thermal zones exist. Creating these by hand is infeasible for larger numbers of zones; instead, they must be identified automatically based on measurement data. In this paper an approach is presented that allows automatically identifying thermal models usable in MPC. The results show that the identified zone models are sufficiently accurate for the use in an MPC, with a mean average error below $1.5\mathrm{K}$ for the prediction of the zone temperatures. The identified zone models are then used in a distributed optimisation scheme that coordinates the individual zones and buildings of a city quarter to best support an energy hub by flattening the overall load profile. In a preliminary simulation study carried out for buildings with floor heating, the operating costs for heating in a winter month were reduced by approximately 9%. Therefore, it can be concluded that the proposed approach has a clear economic benefit.

KEYWORDS:

• Model predictive control
• thermally activated building structures
• distributed optimization
• model identification
• energy management system

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The research leading to these results has received funding from the ‘Stadt der Zukunft’ (engl.: City of Tomorrow) program under grant number 873540, the COMET program under grant number 869341 and the Climate and Energy Fund program in the framework of the RTI-initiative ‘Flagship region Energy’ under grant number 880792. ‘Stadt der Zukunft’ is a research and technology program managed on behalf of the Austrian Ministry for Transport, Innovation and Technology (BMVIT) by the Austria Research Promotion Agency (FFG) along with the Austria Wirtschaftsservice Gesellschaft mbH (AWS) and the Austrian Society for Environment and Technology (ÖGUT); the COMET program is also managed by the FFG and is co-financed by the Republic of Austria and the Federal Provinces of Vienna, Lower Austria, and Styria. The flagship project is funded by the Austrian Climate and Energy Fund in the framework of the research initiative ‘Green Energy Lab’ as part of the Austrian innovation campaign ‘Vorzeigeregion Energie’.