Fraunhofer-Gesellschaft researchers have developed a compact, safe and sturdy fuel cell system that generates electricity and heat in private households from natural gas.

The new fuel cell converts chemical energy directly into electrical energy in a design developed as a simple device for home use. If the design is scaleable it might be a market breakthrough for the fuel cell.

So far fuel cell systems are far too complex.

Dr. Matthias Jahn from the Fraunhofer Institute for Ceramic Technologies and Systems IKTS in Dresden explains, “One always speaks of a fuel cell system. A single cell doesn’t produce enough voltage to obtain a sufficient electrical power. In a fuel cell stack, several cells are connected one to the other. Each of them is about the size of a CD. We call the groups ‘stacks’. Fuel cells convert natural gas directly into electrical energy.”

Fuel Cell Stacking at Fraunhofer IKTS.  Click image for the largest view.  Image Credit: © Fraunhofer IKTS

Fuel Cell Stacking at Fraunhofer IKTS. Click image for the largest view. Image Credit: © Fraunhofer IKTS

Fuel cells are many times more efficient than combustion engines, such as an automobile engine. Engines require an intermediate step. First, they convert chemical energy into thermal energy (heat) and then thermal products are used to make the mechanical energy (force). With this force, an engine can power the wheels or drive a generator, which only then generates the electric power. In the process, a large portion of the originally available energy is lost.

The principle of the fuel cell has been known for over 175 years. But so far there has not been a market breakthrough. The first and main reason was the invention of the electric generator. It knocked the more complex fuel cell out of the running. Only in the 1960s was the technology put into practice by NASA in some Apollo moon missions. In the late 1990s, there were other projects in the automotive industry, which so far have not been able to prevail. The reasons are that the fuel cell is too complex, too expensive, and too unreliable.

“In our project we have made great strides to bring the technology close to the market. European heater manufacturer Vaillant is already producing a small-scale series, which is sold in funded projects to customers,” says Jahn. “For the market breakthrough, the costs still have to be decreased significantly.”

Together with the Vaillant, the Jahn team developed a compact, safe and sturdy fuel cell system that generates electricity and heat in private households from natural gas. The Fraunhofer researchers were particularly responsible for the construction of the prototype, the design of the overall system, the design of the ceramic components and the development of the reformer and the afterburner. The devices are currently being tested in private households in the Callux practice test.

The test units are as compact as classical gas heaters that only produce heat. Moreover, they can comfortably be mounted on the wall and easily be maintained. With an output of one kilowatt, they cover the average current consumption for a four-person household.

The German Federal Ministry of Transport and digital infrastructure BMVI is promoting Callux.

Currently, in the European demonstration project “ene.field”, about 150 further units are being installed in several European countries. In addition, Vaillant started the production of a small-scale series in early 2014. Parallel to the practical test, the two partners are already working on new models.

“Now, it’s all about decreasing production costs and increasing the lifetime of the equipment,” says Jahn.

The new fuel cell miniature power station for home use is based on a solid fuel cell (SOFC) technology. SOFCs operate at a much higher temperature in comparison to competing approaches, such as the proton exchange membrane fuel cell (PEMFC) technology that is used in cars, for example. While PEMFCs only reach 80º, SOFCs can reach up to 850º C. “This allows the SOFCs to be built much more simply and cheaply,” says Jahn.

The electrolyte of an SOFC only transfers oxygen ions, not electrons. Otherwise, there would be a short circuit. “Ceramic is particularly well suited as a material for the electrolyte. It has the desired conductivity and can also endure high temperatures,” says Jahn. As a result, even without the use of precious metals, all reactions proceed smoothly, which is necessary for the direct conversion of chemical energy into electrical energy. If the fuel cell heater is connected to the gas network, a reformer initially converts the natural gas into a hydrogen-rich gas. This then reacts in the stack with the oxygen of the air in a noiseless “cold combustion,” producing power and heat.

The technology looks to be proceeding quite well. In the German market where natural gas is extremely expensive compared to the North American market a highly efficient way to make heat and get electricity has very good prospects. If the technology only doubles or triples the efficiency and cuts consumers gas bills by a half or two thirds the new fuel cell will be a huge hit.

Fuel efficiency in Europe is a major economic and international political problem making much of the continental EU and neighboring states subject to ransoming by their gas suppliers. Something has to happen and your humble writer hopes this technology can be an anchor for a better, lower cost and safer future for everyone in Eurasia. Drive those costs down far enough and the new fuel cell should have a worldwide market.


1 Comment so far

  1. MattMusson on June 13, 2014 7:16 AM

    NASA’s new oxygen generator is two orders of magnitude smaller and more efficient. But – it produces O2 and Methane gas. A small efficient fuel cell like this one could recoup a lot of the remaining power costs of the system.

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