A two-layer decentralized approach to the optimal energy management of a building district with a shared thermal storage

We propose a decentralized scheme for the energy management of a district composed of multiple buildings. Each building is equipped with its own chiller, whereas a single thermal storage is shared among all buildings. The buildings aim at jointly minimizing the electric energy costs while guaranteeing comfort conditions for their occupants, and they can act on their own temperature set-point and the usage of the common storage to this purpose. The problem can be formulated as a constrained optimization program where the buildings decision variables are coupled via some global constraints, due to the shared storage, and the cost function, since the electric energy price depends on the district demand. To distribute the computational load and reduce the amount of transmitted information, we propose a two-layer solution where a central entity takes care of the global constraints by updating some dual variables (outer layer), whereas the primal variables, i.e., zone temperature set-point and storage usage, are optimized locally by the buildings through nested iterations where the price is recomputed based on the updated information on the district demand provided by the central entity (inner layer). (C) 2017, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.