Solar power for energy self-sufficient block of flats in Brütten

The nine-family house is completely independent of external energy supplies and has neither an electricity or gas connection nor fuel supply options. The building envelope, consisting of a matt, full-surface photovoltaic façade and a solar roof, acts as its own power plant. The aesthetic photovoltaic façade made of frameless thin-film modules, which were developed under our project management, is also economically attractive. The biggest technical challenge was not producing enough of the total amount of energy required, but providing it at the right time: the PV envelope produces most of the energy in summer, but the demand is greatest in winter. In a completely self-sufficient stand-alone system, this difference cannot be fed into the public grid and drawn from there when needed. The energy must be "kept in stock" on site using storage solutions.

Batteries are used for short-term storage. For long-term storage, hydrogen is produced by electrolysis, stored in a large tank and converted into electricity by a fuel cell when required. Two underground water tanks act as long-term thermal storage, which are heated by the heat pump when there is excess electricity and are available to it as heat storage in a sink. Thanks to this storage cascade and a sophisticated building management system, the building has a high level of supply security even without a grid connection.