Demand flexibility characterisation in non-residential buildings: A review

Demand flexibility has become a significant consideration in the design and control of buildings for improved grid compatibility and emission-free operations. While there are review papers that have focused on flexibility in residential buildings, reviews that summarise the flexibility-related research in non-residential buildings have not been comprehensively reported. This study addresses that gap and provides a review of existing methodologies for demand flexibility characterisation of non-residential buildings. Critical elements and components are examined and investigated, including the nature and characteristics of energy flexible sources, demand response control strategies, flexibility indicators and quantification functions, flexibility characterisation and aggregation methods, and grid-integrated control for enhanced demand flexibility. It was found that Heating, Ventilation and Air Conditioning (HVAC) systems are the most prevalent energy flexible sources considered in existing studies. A wide range of demand flexibility indicators and quantification functions have been established and most of them rely on a reliable baseline of building performance to serve as a benchmark for comparison. The existing studies have primarily been conducted through simulations, while a limited number of studies used an experimental approach. Optimisation algorithms are often used for demand flexibility aggregation and the development of grid-integrated control strategies, while the feasibility of their practical applications has not been sufficiently studied. Future efforts could focus on the development of easy-to-deploy frameworks with a particular focus on the development of baseline-free indicators, open-source platforms and experimental characterisation procedures for flexibility characterisation of non-residential buildings.