A Framework to Formulate and Aggregate Performance Indicators to Quantify Building Energy Flexibility

Building energy flexibility is being considered an emerging strategy allowing the demand side actively support the operation and control of variable resources-based energy supply. This study presents the development of a framework to formulate and aggregate energy flexibility indicators (EFIs) to evaluate building energy flexibility. EFIs were developed/selected using the important characteristics of building energy flexible sources, performance factors linked with flexibility services and penalty factors posed by the grid. A multicriteria decision analysis method was then used to develop an Aggregated Energy Flexibility Potential (AEFP) function that can consider the interactions between the power grid, buildings and building energy systems to represent the building's overall energy flexibility potential with a single dimensionless value. AEFP can help determine costeffective energy flexible sources and solutions for increased energy flexibility. The performance of the EFIs and AEFP developed was evaluated via a case study with two distinct scenarios through simulations. The photovoltaic system provided a peak power demand reduction of 94%, emissions reduction of 46% and energy cost reduction of 54% to the building with an AEFP value of 0.74 (i.e. 74%), whereas a thermal energy storage system coupled with an air conditioning system helped reduce peak power demand by 56.4%, CO2 emissions by 14.5% and energy cost by 32% with an AEFP value of 0.54 (i.e. 54%). Both scenarios verified the effectiveness of the developed EFIs and AEFP for evaluating building energy flexibility.