Solar Active Houses: Buildings with a Solar Thermal Fraction of at Least 50 % as the Building Standard of the Future
Abstract
By far most of the energy consumption in private households in Germany and Middle Europe is used for space heating. Regarding the German government's aim to reduce the energy consumption in the private sector in combination with an increasing share of renewable energy sources, solar thermal heated houses become more and more attractive. Additionally the European Solar Thermal Technology Panel (ESTTP) of the European Technology Platform on Renewable Heating and Cooling (RHC-TP) and the corresponding German Solar Thermal Technology Platform (DSTTP) consider solar thermal heated houses as a key element for a low-cost and C02-neutral heating energy supply in the future. Therefore the development of houses covering far more than 50 % of their overall heat demand with solar thermal energy comes into the focus. Such houses are called "Solar Active Houses". The main components of a Solar Active House, with regard to single-family houses, are a thermal solar collector with an area of 30 m2 to 50 m2 and a (seasonal) hot water store with a volume of 5 m3 to 15 m3. Due to the fact that Solar Active Houses are relatively new on the building market compared to "conventional" buildings, a scientific basis for the technical design as well as an assessment of the energy concept of those buildings is still missing. These aspects are both elaborated in the project "HeizSolar" (Evaluation and optimisation by simulation of heating supply concepts for living buildings, equipped with solar thermal covering 50 % to 100 % of their total heat demand, and comparison with other C02 reduced heat supply concepts.), financed by the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU), and conducted by the Fraunhofer Institute for Solar Energy Systems (ISE) in cooperation with Solar- und Warmetechnik Stuttgart (SWT), the Ilmenau University of Technology and the Sonnenhaus Institute e.V.. The first key element of the project is a market study of currently available building concepts with low energy demand and high solar thermal fractions. The second key element is a detailed monitoring of nine existing Solar Active Houses in order to get a deep insight of the energy fluxes and energy demands of various types of those buildings. With the monitoring data the primary energy demand can be calculated and the energy concept of Solar Active Houses can be evaluated and compared to other building concepts. Furthermore the data can be used for the validation of detailed numerical simulation models for TRNSYS being developed for different types of Solar Active Houses as a basis for a simulation study and the identification of optimal system configurations.