Scalable aggregation of multi-zone-coupled HVAC flexibility

Develop a computationally efficient aggregation framework that handles multi-zone coupling in HVAC loads while avoiding the tradeoff between restrictive dimensional consistency and poor scalability.

Background

The paper explains that multi-zone HVAC thermal interactions create high-dimensional, interdependent flexibility sets whose projection onto the power subspace is computationally difficult. Existing device-wise geometric approaches generally require dimensional consistency and therefore cannot directly handle these coupled systems, whereas one-step projection approaches can accommodate coupling but become computationally expensive as the number of HVAC loads increases. The authors identify the need for an aggregation framework that simultaneously supports multi-zone coupling and efficient large-scale implementation.

References

In summary, existing approaches face a fundamental tradeoff: they must either impose restrictive dimensional consistency for efficient aggregation or accommodate coupling at the cost of scalability. Thus, developing a computationally efficient aggregation framework that handles multi-zone coupling remains an open challenge.

— Coupling-Aware Aggregation of Multi-Zone HVAC Loads under Uncertainty: A Two-level Framework  (2609.03253 - Liu et al., 3 Sep 2026) in Section I.A, Related Work

Figures~\ref{fig:example_combination} and~\ref{fig:example_combination2} suggest that grouping all loads into a single portfolio tends to yield better results than splitting them across multiple portfolios. We do not prove this holds in general, and counterexamples may exist, for instance when loads are strongly correlated.

— On the Concept of an Optimal Portfolio of Uncertain Flexible Loads  (2609.05176 - Rousseau et al., 4 Sep 2026) in Section 4.3, “Optimal Portfolio of Flexible Loads”