Fuel cells hold the promise of clean, less expensive and environment-friendly energy. They offer a lot of flexibility that is not available with more conventional power technology. They have potential application in a wide range of industrial, commercial, residential and recreational products, where a compact, reliable electric power source is an important or attractive feature.

Critical to the performance and efficiency of these new fuel-cell systems are motors, blowers and pumps that can provide outstanding efficiency, reliable service, safe operation and a broad range of performance capabilities. All these features are offered by US company Ametek Rotron, one of the leaders in the field.

HOW FUEL CELLS OPERATE

Fuel cells are dc power generators. They generate electricity through an electrochemical process that converts the energy stored in a fuel directly into electricity. Fuel cells have many benefits – they produce no particulate matter, nitrogen or sulphur oxides. They have few moving parts and produce little or no noise. When fuelled by hydrogen, they yield only heat and water as by-products. Their wide application can reduce our dependence on fossil fuels and foreign sources of petroleum.

The typical proton-exchange membrane (PEM) fuel cell uses as its electrolyte a polymer membrane. When hydrogen gas from a reformed hydrocarbon fuel is introduced into the system, a catalyst on the surface of the membrane splits the hydrogen gas into protons and electrons. Protons pass through the membrane and react with oxygen to form water, while the electrons, unable to pass through the membrane, flow around it and are conducted to an external circuit. The electrolyte membrane is sandwiched between an anode and cathode. All three components are sealed under heat and pressure into a single membrane/electrode assembly (MEA) that is less than a millimetre thick.

THREE PRINCIPAL COMPONENTS

Explains Shannon Repp, of Ametek Rotron Technical & Industrial Products, explains that a PEM fuel cell consists of three principal components – a fuell-cell stack, a power conditioner and a fuel reformer.

At the heart of each PEM fuel cell are individual MEAs stacked together to provide the power required by the system.
The power conditiopner converts low-voltage electric current from the fuel-cell stack to a higher-voltage ac current that can either be stored or used to power devices. The fuel reformer processes hydrocarbon fuel into hydrogen-rich reformate that the fuel-cell stack converts into electricity.

Motors, blowers and pumps are among the most important components in a fuel-cell system. They are required to move fuels, gases and by-product condensate throughout the system. Since they draw power from the system, they are key factors in its overall efficiency.

A high-efficiency blower or pump has a lower parasitic load on the system and may allow for a reduced fuel-cell stack and lower power inverter costs. The proper matching of a motor's speed/torque curve to its aerodynamic output is especially important in increasing efficiency, thereby reducing its demand on a fuel-cell system.

Major fuel cell developers work closely with motor-blower and pump suppliers, such as Ametek Rotron in custom-designing components that meet a system's specific needs.

Fuel cells rely on brushless blowers and pumps to supply air to the reformer and cathode as well as ventilation and cooling to maintain proper enclosure conditions.

Brushless motor technology offers a number of critical advantages, including high efficiency, spark-free and maintenance-free operation, outstanding reliability and long service life. Its microprocessor-based electronics allow for accurate performance control and rapid trasnsient response time for faster power availability.

The hydrogen gas produced in PEM fuel cells is highly flammable, so use of a spark-free brushless motor-blower often is mandatory. Despite their ompact size, brushless motors and motor-blowers are sufficiently robust to meet fuel cell developers' stringent vibration, pressure containment, gas leakage, condensate management and low noise requirements.

Ametek Rotron, for example, provides the fuel cell industry with the broadest range of advanced brushless motors, blowers and pumps, as well as the proven ability to customise blower and pump performance to the end-use application.

More information is available on www.brushlessblowers.com.