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Improving the energy efficiency of heating systems is of great significance in building energy saving. This paper investigates a time-average total cost minimization problem of heat pump systems. Firstly, heat pump systems and thermal dynamic building model are built considering thermal inertia. To solve temporally coupled constraints and uncertainties of the outdoor temperature and real-time electricity price in the formulated problem, the paper proposes an online optimization algorithm for building heating based on Lyapunov method. Extensive simulation results show that this method could achieve user comfort and reduce energy cost effectively.

This paper studies the online optimal energy management problem for the building heating system. This system is driven by electric heat pumps, and equipped with the thermal energy storage (TES) that provides heat flexibility. The temporal coupling introduced by building temperature dynamics and TES energy level dynamics, together with the uncertainties of real-time electricity price and outdoor temperature, pose the optimal energy management problem a computationally challenging one. Hence, based on the Lyapunov optimization method, an online algorithm is proposed to minimize the long-term time average cost of heating system. Our algorithm can ensure the building temperature constraints and TES energy level constraints are satisfied all the time. The maximum optimality gap of our algorithm is also rigorously derived. Simulation results show that this algorithm can achieve user comfort and reduce energy cost effectively.

Aircraft fuel system, which provides a continuous source of fuel to the engine, is an important component of the aircraft. Although the sequential fuel feed strategy for the symmetric arranged multi-tanks aircraft is widely used in today's aircraft, the fuel feed strategy of the asymmetric arranged multi-tanks is still a challenge. In this article, a two layer offline approach is developed to obtain the fuel feed strategy to minimize the difference between the actual center of gravity (CG) and the desired CG. The performance of the proposed approach is tested in a case study based on the test data of aircraft pitch movement. The result indicates that the proposed approach solves the problem with an offline manner from the optimization perspective.