The self-sufficient solar house Freiburg

The Fraunhofer-Institute for Solar Energy Systems is planning and building a completely selfsufficient solar one-family house in Freiburg, Germany. The entire energy demand for heating, electricity and cooking is supplied by the sun. The combination of highly efficient solar systems with conventional means to save energy is the key to the successful operation of the house. The meteorological conditions in Freiburg (48 degrees latitude) are characterized by abundant solar radiation in summer but long dark periods in winter. Therefore, seasonal energy storage has to be provided. It is accomplished by electrolysis of water and pressurized storage of hydrogen and oxygen. The energy for electricity and hydrogen generation is supplied by solar cells. Hydrogen can be reconverted to electricity with a fuel cell or used for cooking with a catalytic heater. It also serves as a back-up for low temperature heat. There are provisions for short term storage of electricity and optimal routing of ener gy.