Hydrogen Coolers

Why is hydrogen used in generator cooling?

Large electrical generators have used hydrogen as a cooling medium for almost 100 years. Hydrogen is preferable to air because of its higher thermal performance, but it presents unique challenges to machine manufacturers, especially when used under pressure.

As hydrogen cooling is generally only reserved for the very largest generators (such as those found in the nuclear industry), the market for hydrogen cooled machines is smaller than for other types of cooler. This means there are very few cooler manufacturers who can claim to have the experience and knowledge to design and build equipment of this type.

How does hydrogen cooling work?

Hydrogen / air mix is circulated through the active parts of the generator. It is then directed into the coolers where the heat is transferred into water. This heat transfer takes place on a near-standard fin and tube arrangement.

While the heat transfer process is relatively conventional, the mechanical aspects are unique. With extended operational hours, often running for months without stopping, the mechanical integrity is paramount. Tolerances are tight to ensure that hydrogen cannot escape. Flex is minimal to avoid fatigue and failure.

The challenges of hydrogen cooling

A combination of air and hydrogen can be explosive. Therefore, the installation of the cooler in the generator must be gas tight. Hydrogen coolers must have a robust frame surrounding the heat transfer components to avoid destructive vibrations.

At Sterling Thermal Technology, we design and manufacture hydrogen coolers that ensure a perfect airtight installation with the flanges of the generator. This provides a reliable and safe heat exchange solution.

There are various technical considerations to ensure reliable and long-lasting hydrogen coolers. Generally built in a jig, it is imperative that both tube plates are set to tight tolerance dimensions with the required levels of flatness, squareness and parallel faces.

The frame that supports the two tube plates not only maintains this, but is also required to avoid resonance. Typically, the coolers are supported only on the two tube sheets, often leaving more than 6 metres unsupported. The frame must avoid the natural frequencies of the machine.

Extra care needs to be taken when it comes to the support of tubes. Our unique design makes sure that each tube is individually supported. Combined with robust Elfin multi-tube plate-fin cores, fatigue is minimised and vibration-induced failure is avoided. Find out more about our finned tube technology.

Purchasing hydrogen coolers from Sterling Thermal Technology

Customise the tubes, fins and materials 

We offer horizontal and vertical hydrogen coolers with a wide variety of geometries and materials to suit your needs. Materials include:

• Tubes: copper, CuNi90/10 or stainless steel.
• Tube sheets: carbon steel, naval brass or stainless steel
• Fin type: our Elfin plate-fin extended surface tubes, ribbon wound or wire wound
• Fins material: aluminium, copper alloys, stainless steel, or titanium.

Refurbishment and repair services for your coolers 

Should you need to refurbish an existing hydrogen cooler, we can help. Our services include, but are not limited to, repairs and replacement of headers or tube sheets, retubing and tube bundle replacement.

When possible, we save you money and reduce delivery time by reusing existing components.

Our service starts with understanding your requirements and doesn’t stop after the equipment is installed. For a full-service partner in heat exchanges, contact us today. Tell us about your needs and find out how we can help.

If you are looking for a different type of heat exchanger, explore our website. We have gas coolers, air to air coolers, OFAF transformers and more. Visit our products and services page, or contact us.