eHomes – smart and electric

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Smart homes are not all about comfort and safety. Web-based technologies can also make a house more energy-efficient – especially if it produces energy itself like the House of Living Labs at the FZI Research Center for Information Technology in Karlsruhe. A photovoltaic system installed on the roof generates electricity for the one-bedroom test flat, while a combined heat and power unit provides heat in the winter and – if necessary – air conditioning in the summer. The centralized Energy Management System gathers together all of the data: how much energy is provided by local utilities? How much electricity is generated in the house, and where? How much energy is consumed by which device?

Doing the laundry while the sun shines

The eHome knows how much energy is needed

When someone in the test flat wants to put on a load of washing, all they need do is switch on the washing machine via a control panel. However, they may notice that the machine does not start up, at least not immediately. If the energy storage facility reports to the Energy Management System that reserves are low, the wash will be put off until the afternoon – by which time the solar power system will have replenished its energy reserves.

No energy transition without smart energy use

The eHome generates its own electricity.

Buildings which produce energy themselves and efficiently control their energy consumption are not only kind to the environment. They are also ideal for switching from fossil fuels to renewable energy sources. This is because solar and wind power systems – unlike coal-fired power stations – do not generate energy continuously. This leads to fluctuations in the power grid which buildings fitted with a smart energy management system can balance out by drawing from the grid only when plenty of energy is being supplied. When energy levels are low, they switch to the in-house system. The house which engineers at RWTH Aachen University’s E.ON Energy Research Center have in mind is even entirely self-sufficient and independent of the power grid.

Fully electric and self-sufficient

Everything in an eHome – PCs, heating and hot water system, and even the car – runs on electricity. Rather than being supplied by the nearest power station, all of the energy required comes from the solar power system on the roof and is stored in batteries until it is needed. To minimize power consumption, the engineers have opted for direct current rather than the alternating current supplied by utility companies.

“Overall efficiency in this entirely direct-current electrical house is generally quite high. Moreover, the deployment of an in-house power-electronic-based direct-current system enhances the observability, controllability and safety of the resources and the loads”, says project leader Antonino Riccobono. Mechanical engineers at RWTH Aachen University are currently working to perfect the heating system in the house. Electric wires routed through the walls and floors will distribute heat throughout the eHome. Engineers are planning the electrics and developing the software, which will ultimately ensure very carefully coordinated energy generation and energy consumption – a “smart” system, in other words.


E.ON Energy Research Center

The E.ON Energy Research Center combines different elements of energy research: the generation, transformation, distribution and storage of energy, and links them to behavioural, social and economic questions. Thanks to this interdisciplinary concept, the Research Center, which was founded within the framework of a public-private partnership between E.ON and RWTH Aachen, is unique in the German and European university sphere.