Engineering

Fuel Cell in the House provides electricity and heat

Energy transformation can be supported also in the domestic heating cells: this year come as many heat plants on the market like never before, which are powered by a fuel cell.

The heating industry looks longingly to Japan: there already more than 100.000 heating systems. In EU, there are significantly less. by 2015, just the brand has been exceeded by 14,000 devices. But this year the industry will start. 2016 come as many new plants on the market like never before. And the series production to let prices tumble.

Two years ago, a budget between 30-40k euros needed to spend to make installing a fuel cell heating. The new units coming on the market, are only around 20,000 euros and to the Federal Government has initiated a support program, which accepts grants by 40 percent of the eligible costs. Thus, the fuel cell heating is lucrative.

Climate-damaging emissions decrease by 50%

Heating systems with fuel cells are technically and interesting for the environment anyway. As mini power heat and power plants (CHP) for the production of heat and electric energy reached an overall efficiency of over 90%. The plants with natural gas and hydrogen produced from renewable energy or biomass and methane are operated. A so-called reformer converts natural gas to a hydrogen-rich gas first. This reacts with the oxygen in the air in an electrochemical reaction. The result is water vapor. The remaining residual gas is burned in the afterburner.

Fuel Cell in the House
Foto: Vaillant

The CHP plants generate heat and DC with a very high degree of efficiency. An inverter converts this into alternating current which can be used in the House. A heat exchanger is the waste heat from the fuel cell and available from the afterburner for the heating and hot water. Compared with the current burning technology energy costs by about 25% and harmful emissions by up to 50% can be reduced.

Complete practice test

Such a small device with solid oxide fuel cell (SOFC) has now developed to the point of production the manufacturer Vaillant in a project funded by the Federal Ministry of economy and energy (BMWI). In the Callux project between 2008 and 2015 approximately 500 fuel heating appliances in single and two-family homes have been installed and tested.

Thereby, the tested systems in over five million hours of operation produced more than three million kWh of electrical energy. In this practice test succeeded in halving the unit dimensions and the weight of the device.

Vaillant
Foto: Vaillant

Construction of the current XellPower BZ heater: below is the fuel cell system with auxiliary units, above the gas condensing additional heater. That compact unit for the basement of single and two-family homes weighs about 150 kg.

Now, the debris weighs only 150 kg. Also succeeded, to simplify the interface with the existing house technology and to reduce the need for maintenance. For the start of production, the various functions had to be accommodated also in a housing.

Simple trick with the vacuum

And this case is now a vacuum enclosure, which is crucial for the safety in operation of a single or two family house. “We could implement a very simple and at the same time a very good security concept in our fuel cell heating appliance”, says Jochen Paulus, Director of technology development fuel cell at Vaillant. “Because all system components in the vacuum to work, an exhaust fan in conjunction with a few temperature sensors enough, we need no further protective measures or sensors.”

The unit covers the basic needs of a single with an electrical output of 0.7 kW and a thermal output of 1.3 kW two family house.

When it gets really cold in the winter, a gas condensing boiler is integrated in the unit can be switched. The unit can be used for either network provide relief or completely independent of the mains, if it unfolds its contribution to the energy revolution. The device is self-sufficient, it needs no overland power lines. And it stands in contrast to wind turbines in the basement, where it sees none.

Currently, nine plants on the market manufacturing fuel cell according to statistics of the initiative. Here you will find the product overview.

An idea of the Karlsruhe Institute of technology is interesting: with a new technology energy for heating can be obtained from heated groundwater layers in the winter and cool in summer.