Modular facade retrofit with renewable energy technologies: the definition and current status in Europe

Abstract Over the last decade, a number of research and innovation projects have started developing modular facade retrofit solutions which integrate on-site renewable energy technologies. Although there are a growing number of academic articles and demonstration projects showcasing their achievements, the overview of current status and development trend are missing. It is difficult for policymakers, the public and fellow researchers to understand the evolution of modular facade retrofit technologies and who are the important players in the field. As a part of the ongoing European Commission Horizon 2020 project team, the authors decided to write this review article that meets the above needs. Due to the lack of clarification in previous studies, this article firstly introduced and defined the term of Modular Facade Retrofit with Renewable energy technologies (MFRRn), then provided its classification and the review of recent evolution. The MFRRn refer to the retrofitting process that thermal insulation, solar and wind harvest technologies are integrated with the exterior finish of building using modular approach. According to our definition, the MFRRn should fulfil four basic aspects: work to be conducted on existing buildings, work to be undertaken on the facade, using a modular approach, and integrating renewable energy technologies during the retrofit. This study then reviewed 173 research projects funded under the European Commission the seventh Framework, the Horizon 2020’s Energy Efficient Buildings programme, the International Energy Agency Energy in Buildings and Communities (IEA EBC) Annex 50 ‘Prefab Systems for Low Energy/High Comfort Building Renewal’ project, the European Cooperation in Science and Technology (COST) Action TU1403 ‘Adaptive facades network’. The review shows that at least 14 European Commission research projects and 4 case studies mentioned in COST TU1403 and IEA Annex 50 have involved in certain of level of MFRRn development. Their research progress, timeframe, funding scale and funding flow to nations and contributions from key institutes are analysed. Finally, the current challenges regarding the MFRRn developments and implementations are discussed, and future research focus is proposed.