| Author: | Tang, Hong |
| Title: | Flexibility quantification, system optimization and optimal control of energy-flexible and grid-responsive buildings |
| Advisors: | Wang, Shengwei (BEEE) |
| Degree: | Ph.D. |
| Year: | 2023 |
| Subject: | Buildings -- Energy conservation Buildings -- Environmental aspects Hong Kong Polytechnic University -- Dissertations |
| Department: | Department of Building Environment and Energy Engineering |
| Pages: | xx, 176 pages : color illustrations |
| Language: | English |
| Abstract: | The rapid development of remote telemetry, control and communication technologies in smart grids enables the demand side to provide energy flexibility for power grid economy and reliability in the context of increasing renewable energy penetration. The building sector, as a consumer of large amounts of electricity, has various flexible loads that can be effectively utilized for such purposes if buildings and their energy systems are properly designed and controlled. However, there lacks a systematical investigation of building energy flexibility with respect to the demand response potentials across multiple timescales. An effective assessment method is required to evaluate flexibility performance and identify the roles and contribution mechanisms of buildings to multiple flexibility services for smart power grids. The economic benefits of flexibility enhancement measures and the corresponding real-time control performance when building provide multiple flexibility services are not yet fully investigated. There is still a lack of promising business models and corresponding control strategies for unlocking the building energy flexibility in practical implementation to clear the hurdles in customer acquisition, trading optimization, and benefits sharing. Therefore, the aim of this study is to develop a comprehensive methodology for the categorization and quantification of building energy flexibility, develop the optimal design method for building-integrated storage systems to enhance flexibility, and develop the optimal dispatch strategy for hybrid building energy systems and essential technical foundation for future business models to unlock the huge flexibility potential of building cluster. A systematic methodology is proposed for categorizing the building energy flexibility as load covering, load shifting, moderate regulation, load shedding and fast regulation according to the demand response speeds, response duration and response direction to power grids. A comprehensive flexibility quantification framework is developed to assess building energy flexibility based on flexibility categories. The impacts of different system design and control parameters on flexibility performance are investigated quantitatively. Considering their potential contribution to multiple grid flexibility service, a life-cycle economic analysis and the system optimization of thermal energy storage, new and second-life batteries in buildings is conducted. Optimal configuration of multi-type storage systems can be obtained by comparative economic analysis on life-cycle cost saving and discounted payback period considering the system degradation. By considering the trade-off between economic benefits and occupants' comfort, a model-based predictive dispatch strategy is proposed to optimize the contribution and coordination of multiple resources in building energy systems. Test results show that proposed strategy reduces the operational costs by 26.1% and achieves peak reduction at 8.2%. The impacts of uncertain and high-granularity real-time grid control signals on the indoor environment are negligible. A cooperative game-theory based multi-level dispatch strategy for self-aggregated building clusters is developed to optimize the flexibility profits and profit-sharing mechanism from multiple revenue streams. The proposed strategy can effectively obtain significant flexibility profits, up to 20.4% of the electricity cost and fairly distribute the profits among individual buildings while ensuring the required minimum bidding capacity in practical implementation. A Stackelberg game-theory based interactive flexibility engagement scheme, based on the intermediary aggregator business model, is proposed to capture the interaction between demand-side building users and the aggregator agent. Results show that a win-win situation is achieved where the aggregator increases the profit by 37.4% and buildings achieve the cost saving by 5.6%-5.9%. |
| Rights: | All rights reserved |
| Access: | open access |
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