A control system approach to optimal maintenance planning for building retrofitting project

Existing studies paid most attentions to the strategic planning of building retrofitting project. During the actual operation, the overall energy performance of the retrofitting project deteriorates over time owing to the usage and failures of the retrofitted facilities. For the sustainability of energy efficiency, the maintenance plan optimization for the retrofitted facilities must be considered, which suggests the possibility to sustain the building energy efficiency during operating. However, the overall energy performance reveals strong time dynamics subject to the failures and maintenance actions, which make the maintenance plan optimization a complicated problem. This paper characterizes the dynamics of the totality of the retrofitted facilities by the multi-state system models governed by a discrete-time Markov process. The impacts of both preventive and corrective maintenance actions on the over energy efficiency of the plant are then quantified by the present model. The optimization problem is thus casted into a stochastic optimal control problem which aims at maximizing the long-term energy efficiency and financial payback. An MPC based approach is employed to solve the present control problem. Finally, a case study is conducted to demonstrate the effectiveness of the present approach.