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In this paper, the potential of a facade element with switchable U -value and g -value is investigated. This new switchable facade element consists of a series of air-filled cavities separated by opaque films, that can be rolled up or down between two fixed layers, thus switching the thermal and optical properties from a thermally insulating state to a conducting state. A first prototype has been built and measured in the insulating state and the properties of the facade element have been optimized using a theoretical analysis at the facade level. The U -value can be switched from a value of 0.35 W m −2 K −1 in the insulating state to a value of 2.7 W m −2 K −1 in the conducting state. Building energy simulations using EnergyPlus showed that the sum of the heating and cooling demands could be reduced by about 30% with the switchable insulation used as a window application or in front of an opaque massive wall. Even better performance could be achieved by reducing the frame or edge losses. The influence of the thermal mass, and finally the influence of orientation on the overall performance are also investigated and were found to be non-negligible.

This paper describes a method to overcome current limitations in BIM software to design Building Automation and Control Systems (BACS) functions of Heating Ventilation and Air Conditioning (HVAC) systems through the extension of the IFC-files with information on control functions. The method is illustrated with the description of control functions for a use case including a boiler, a thermal storage, an air handling unit and a floor heating system modelled with a widely used BIM software tool. The focus is set on the description of three simple control functions: the definition of a heating curve, the setup of time schedules for the air handling unit and the flow temperature control for the heating circuit. The proposed method is based on available software tools linked together and enables adding complementary information on controls into the IFC-file, checking it for consistency, extracting and converting the IFC content into a linked data format. The use of semantic web technology allows for interoperability with various applications like e.g. software used for the commissioning or the supervision of HVAC systems and thus can contribute to reduce current quality and performance deficits of these systems.

The increasing global energy demand, the foreseen reduction of available fossil fuels and the increasing evidence off global warming during the last decades have generated a high interest in renewable energy sources. However, renewable energy sources, such as wind and solar power, have an intrinsic variability that can seriously affect the stability of the energy system if they account for a high percentage of the total generation. The Energy Flexibility of buildings is commonly suggested as part of the solution to alleviate some of the upcoming challenges in the future demand-respond energy systems (electrical, district heating and gas grids). Buildings can supply flexibility services in different ways, e.g. utilization of thermal mass, adjustability of HVAC system use (e.g. heating/cooling/ventilation), charging of electric vehicles, and shifting of plug-loads. However, there is currently no overview or insight into how much Energy Flexibility different building may be able to offer to the future energy systems in the sense of avoiding excess energy production, increase the stability of the energy networks, minimize congestion problems, enhance the efficiency and cost effectiveness of the future energy networks. Therefore, there is a need for increasing knowledge on and demonstration of the Energy Flexibility buildings can provide to energy networks. At the same time, there is 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. In this context, the IEA (International Energy Agency) EBC (Energy in Buildings and Communities program) Annex 67: “Energy Flexible Buildings” was started in 2015. The article presents the background and the work plan of IEA EBC Annex 67 as well as already obtained results. Annex 67 is a corporation between participants from 16 countries: Austria, Belgium, Canada, China, Denmark, Finland, France, Germany, Ireland, Italy, The Netherlands, Norway, Portugal, Spain, Switzerland and UK. ispartof: Energy and Buildings vol:155 pages:25-34 status: published

The energy consumption of buildings lies often far above the performance objectives of the design phase. This is due to several factors among other serious deficits in the energy operation of building services. TOPAs adopts the principle of continuous performance auditing by not only considering energy use but also knowledge and understanding of the buildings use and their climatic state. Thus it provides a holistic performance auditing process through supporting tools and methodologies that try to minimise the gap between predicted and actual energy use. TOPAs offers an open BMS (Building Management System) IoT driven framework. This framework is composed of core services to connect to any BMS and aggregate all the information in an open platform. Add-on services are also available to improve the understanding of buildings and reduce further the gap.

Die Verringerung des Heizenergiebedarfs im Gebäudebestand ist eines der zentralen Themen der Energiewende. Immer noch fließen rund 40 % des deutschen Endenergiebedarfs in Heizung und Warmwasser. Will man die Klimaschutzziele der Bundesregierung mit einer CO2-Reduktion um 80 % bis 2050 erreichen, so müsste die Sanierungsrate mindestens verdoppelt werden. Das Fraunhofer-Institut für Solare Energiesysteme ISE in Freiburg hat mit seinen multifunktionalen Fassadenelementen jetzt erstmals an einem Mehrfamilienhaus der Wohnungsbaugesellschaft ABG Frankfurt Holding ein minimal-invasives Sanierungskonzept demonstriert, das Sanierungen erleichtern könnte.