Work

Grid-interactive real-time HVAC optimization in a commercial building with thermally activated slabs

Year: 2026

Type: article

Abstract: Growing renewable energy sources in the electric grid require energy-efficient and flexible consumers. Buildings account for a large share of global electricity demand, and their heating, ventilation, and air conditioning (HVAC) systems offer considerable potential for energy savings through improved control, as well as for load shifting due to their large thermal capacity. While model predictive control (MPC) has been widely studied for improving building performance, real-time implementations that quantify both efficiency and flexibility under practical operational and implementation constraints for complex HVAC systems remain largely unexplored. Therefore, this study presents a real-time-capable MPC application using mixed-integer linear programming (MILP) for a complex all-electric HVAC system with thermally activated concrete slabs, evaluated using a validated simulation model. The controller jointly optimizes electricity consumption under varying electricity tariffs while responding to real-time and 24-h ahead grid signals. Results show average electricity savings of 20.4 % compared to the conventional control, with even greater savings during transitional seasons. In addition, the approach improved compliance with temperature limits. Significant flexibility potential was demonstrated, with the 24-h ahead signal increasing average positive flexibility by 38.0 % compared to the real-time signal. However, estimating flexibility costs proved challenging due to the long thermal memory of the slabs and complex heat transfers. Moreover, real-time constraints limited solver convergence, resulting in potentially suboptimal operation. The findings demonstrate the feasibility of real-time MPC for energy-efficient and grid-responsive HVAC operation under real-world constraints, while highlighting the key limitations and trade-offs encountered in achieving this.

Source: Energy and Buildings

Authors: Daniel Bull, Adrian Bürger, Markus Bohlayer, Marco Braun, Anke Weidlich

Institutions: University of Freiburg, Karlsruhe University of Applied Sciences

Language: English

Topic: Building Energy and Comfort Optimization

Subfield: Building and Construction

Field: Engineering

Domain: Physical Sciences

SDGs: Affordable and clean energy, Climate action, Industry, innovation and infrastructure

Open Access status: hybrid

Estimated APC paid: $4,260

Funder: Ministerium für Wissenschaft, Forschung und Kunst Baden-Württemberg