Browsing by Author "Anghel, Ionuţ"

This paper addresses the problem of proactive planning and optimizing the operation of a Systems of Systems (SoS) over a time horizon while considering the characteristics of each constituent system and complex interactions among them. We define a mathematical formalism for modeling complex systems composed of a mesh of sub-systems with linear and non-linear behaviors and abstractions like discrete time, atomic systems and interconnection of atomic system. The proposed modeling approach is simple enough to allow fast computations and simulations, and at the same time complex enough to capture the essential features of the real system thus allowing the mapping of proactive optimization problems to Mixed-Integer Optimal Control Problems. The proactive planning uses hierarchical optimization processes that compute predictions and optimization plans at various time granularities, each finer layer plan adjusting and refining the ones with higher granularity. To show case our approach we model a Data Center which is a well-known case of a large scale complex system aiming to plan and optimize its operation to use as much as possible the locally produced renewable energy and optimize its integration in smart grid advanced context. Simulation based results show a reduction of 5% of the carbon footprint and at the same time an increase in profit of more than 14% due to flexible energy shifting.

In this paper, we have considered Data Centres (DCs) as computing facilities functioning at the crossroad of electrical, thermal and data networks and have defined optimisation techniques to exploit their energy flexibility. Our methods are leveraging on non-electrical cooling devices such as thermal storage and heat pumps for waste heat reuse and IT workload execution time shifting and spatial relocation in federated DCs. To trade energy flexibility we have defined an Energy Marketplace which allows DCs to act as active energy players integrated into the smart grid, contributing to smart city-level efficiency goals. Reinforcing this vision, we have proposed four innovative business scenarios that enable next generation smart Net-zero Energy DCs acting as energy prosumers at the interface with smart energy grids within smart city environments. Simulation experiments are conducted to determine the DCs potential electrical and thermal energy flexibility in meeting various network level goals and to assess the financial viability of the defined business scenarios. The results show that DCs have a significant amount of energy flexibility which may be shifted and traded to interested stakeholders thus allowing them to gain new revenue streams not foreseen before.