Principles of Energy Flexible Buildings : Energy in Buildings and Communities Programme Annex 67 Energy Flexible Buildings

Abstract

Energy flexibility of a building is really not a new concept. It originates from the demand side management regime, which for decades has been applied by the designers and operators to foster stable and bottleneck-free operation of the electrical energy systems. However, as the transition of both the demand and supply side of the energy system imposes new challenges to the management of the whole energy system, such as the variability and limited control of energy supply from renewables or the increasing load variations over the day, the energy Flexible Building concept has gained more international attention. However, despite the given attention, a uniform understanding and a commonly accepted definition is still not in place for this building concept. The lack of a clear international framework for the requirements and properties of energy Flexible Buildings leads to numerous definitions that are being developed in parallel and are applied to specific cases when evaluating and/or quantifying energy flexibility. Although the concept of energy flexibility of buildings is relatively simple to understand, its application in reality can be complex and difficult to explain in simple terms. This complexity is not helped by the myriad of ways in which energy flexibility can be achieved or the wide range of stakeholders involved; especially when many stakeholders have very little understanding, or interest, in the supply and demand of energy in buildings. There was, thus, a need for increasing knowledge on, and demonstration of, which services energy flexibility buildings can provide to the energy networks. At the same time, there was a need for identifying critical aspects and possible solutions to manage this energy flexibility, while maintaining the comfort of the occupants and minimizing the use of non-renewable energy. Based on the above the Executive Committee of the IEA Technical Collaboration Programme (TCP) Energy in Buildings and Communities (EBC) decided to initiate Annex 67 Energy Flexible Buildings in June 2015 with an end date of November 2019. The objectives were: - development of a common terminology, a definition of ‘energy flexibility in buildings’ and a classification method, - investigation of user comfort, motivation and acceptance associated with the introduction of energy flexibility in buildings, - analysis of the energy flexibility potential in different buildings and contexts, and development of design examples, control strategies and algorithms, - investigation of the aggregated energy flexibility of buildings and the potential effect on energy grids, and - demonstration of energy flexibility through experimental and field studies. The work of IEA EBC Annex 67 has been documented in 7 deliverables reports; the titles of these reports are: - Principles of Energy Flexible Buildings (the present report) summarizes the main findings of Annex 67 and targets all interested in what energy flexibility in buildings is, how it can be controlled, and which services it may provide. - Characterization of Energy Flexibility in Buildings describes the terminology around energy flexibility, the existing indicators used to evaluate the flexibility potential and how to characterize and label energy flexibility. - Control strategies and algorithms for obtaining Energy Flexibility in buildings reviews and evaluates control strategies for energy flexibility in buildings. - Experimental facilities and methods for assessing Energy Flexibility in buildings describes several test facilities including experiments related to energy flexibility and draws recommendations for future testing activities. - Stakeholder perspectives on Energy Flexible buildings considers the view point of different types of stakeholders towards energy flexible buildings. - Examples of Energy Flexibility in buildings summarizes different examples on how to obtain energy flexible buildings. - Project Summary Report contains a very brief summary of the outcome of Annex 67. The main findings of the five key deliverables are included in chapters 3-7 of the present report. The five key deliverables are: Characterization of Energy Flexibility in Buildings; Control strategies and algorithms for obtaining Energy Flexibility in buildings; Experimental facilities and methods for assessing Energy Flexibility in buildings; Stakeholder perspectives on Energy Flexible buildings; and Examples of Energy Flexibility in buildings. The third chapter of the present report unfolds the characterization methodology, terminology and definition developed by the Annex and the possible application of the methodology. The fourth chapter is devoted to the control of energy flexible buildings, which is the core of this concept. It demonstrates which control strategies and algorithms can provide energy flexibility from buildings and identifies critical aspects and possible solutions to manage energy flexibility. The fifth chapter gives the overview of the existing test facilities located in Belgium, Canada, Denmark, Finland Germany, Norway, Spain and Switzerland, which are designed and constructed to test different control strategies and combination of components, and thus evaluate the energy flexible building under realistic conditions. The sixth chapter provides the feedback on energy flexible buildings from the perspective of nine types of stakeholders. It presents and discusses their roles, motivations, and potential barriers to energy flexible buildings. The chapter closes with recommendations for how the different types of stakeholders should be approached and motivated in order to become an active part of the energy flexible concept The seventh chapter summarizes the good examples of energy flexibility collected during Annex 67. It describes the scope and focus of the examples, followed by a more detailed description of a sample of specific examples that describe the different sources of flexibility. It ends by evaluating the statistical range of the described examples. It is hoped that the present report will not only provide an impression of what energy flexibility in buildings is and how it can be obtained, but also be a source of inspiration for future research and development in this area.