Paper Conference

Proceedings of ASim Conference 2012: 1st Asia conference of IBPSA-China, Japan, Korea


Optimization for control of an integrative system with thermal and electrical storage

Tatsuo Nagai, Takuya Suzuki

Abstract: The present paper proposes an optimization method for minimizing the electricity consumption or peak electrical demand of a building equipped with both a thermal storage tank and a battery. We use dynamic programming as a dynamic optimization method. In dynamic programming, we need to minimize the number of states and control variables in order to avoid the ‘curse of dimensionality’. Therefore, we use a kW-based approach for modeling components, so that the number of state variables and the number of control variables can be reduced to two each. Based on the proposed optimization method, we investigate optimal scheduling for each objective function such as the cumulative electricity or peak electrical demand, assuming a model office building in Tokyo. For the purpose of minimizing cumulative electricity consumption, the optimization results suggest operations that minimize battery utilization in order to decrease charge and discharge loss. However, for a building equipped with photo-voltaic (PV) panels, there are cases in which it is preferable to use a battery and thermal storage over the weekend, during which the power generated by PV surpasses the electrical load. In order to minimize peak electrical demand, the optimization results indicate the full use of both the battery and thermal storage during peak days. By minimizing the electrical charge, a considerable reduction in peak power is achieved while the cumulative consumption does not increase significantly because the need for the peak reduction is limited to only a couple of days during summer. Finally, we discuss future studies involving the proposed optimization technique.
Pages: 612 - 619