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While induction heating is not a new technology, it is in fact a green technology and can be a part of an organization's sustainability program. It does not consume fossil fuels, and it does not produce any hazardous emissions or carbon dioxide (CO2).

What is induction heating?

Induction heating is a fast, efficient, precise, repeatable, non-contact method for heating metals or other electrically conductive materials. An induction heating system includes a power supply that converts line power to an alternating current. This current is delivered to a workhead and work coil, creating an electromagnetic field within the coil. The workpiece is placed in the coil, where this field induces a current and generates heat in the workpiece. The water-cooled coil is cool to the touch and is placed around or adjacent to the workpiece. It does not touch the workpiece, and heat is generated by the induced current flowing in the workpiece.

The workpiece can be a metal such as steel, copper, aluminum or brass, or a semiconductor such as carbon, graphite or silicon carbide. Non-conductive materials such as plastics or glass are inductively heated using an electrically conductive susceptor, typically graphite.


Why is induction a green technology?

While induction heating is not a new technology, it is in fact a green technology and can be a part of an organization’s sustainability program. It does not consume fossil fuels, and it does not produce any hazardous emissions or carbon dioxide (CO2). When compared to gas heating, induction offers a safer, cleaner and more comfortable work environment. Compared to torch heating, induction is flameless and introduces less heat into the workplace while eliminating smoke, waste heat, noxious emissions and loud noise. It is also space-efficient, not occupying large amounts of floor space like furnaces often do.


Dr. Girish Dahake working in Ambrell’s applications laboratory in Rochester, N.Y.

Many processes that produce emissions can be converted to induction heating, including:

  •  Flame preheating
  • Gas-fired oven heating
  • Welding torches for joining
  • Flame brazing
  • Flame melting
  • Flame hardening
  • Flame shrink fitting


Induction Heating is a Safer Technology

In addition to the improved air quality that comes with induction heating, there are other significant employee safety benefits.

  • Reduction in risk of contact burns: Since induction heats only a zone of the workpiece, there are limited hot areas, which lessens the risk of employee contact. This significantly reduces the risk of contact burns when compared to the outside of ovens or exhaust systems from gas heating.
  • Zero explosive gases: Induction uses electricity for the energy source. This eliminates the handling of high-pressure explosive gases. These gases are often transported in a hot, crowded environment, which increases the risk of catastrophic failure.
  • No ultraviolet (UV) exposure: Unlike flame heating, induction releases no UV into the environment. This eliminates the risk of UV damage that can occur to the skin and eyes of employees from flame heating sources.

Of course, there are safety considerations with induction heating. Proper installation, signage, employee training, personal protective equipment and lockout procedures can help mitigate risk.


Induction is a More Efficient Heating Method

Induction is a uniquely energy-efficient heating process that converts 70-90% of the energy consumed into useful heat. When compared to electric ovens, which are generally only 45% energy efficient, induction heating has two times the overall efficiency. Gas ovens are typically only 25-30% energy efficient, indicating induction can be up to three times as efficient. Since induction requires no warm-up or cool-down cycle, startup and shutdown heat losses are eliminated. The repeatability and consistency of the induction heating process make it highly synergistic with energy-efficient automation systems.


Induction Supplies More Consistent Output than Oven Heating

The use of constant-flow induction heating results in significantly higher efficiency than batch oven heating. Losses in both energy and time due to oven loading and unloading are eliminated with induction heating.

Induction enables a consistent flow of parts, which is even more critical if onward steps in the manufacturing process require heated parts. This reduces the heat loss from the part when it reaches the next step, thus increasing the overall efficiency of the cycle. This overall savings is not only realized in production efficiency but also results in the better use of heating energy.


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Fig. 1. Induction heating vs. oven heating


Induction Compared to Gas Oven Heating

In this scenario (Fig. 1), a client using an oven switches to induction. The environmental benefits are considerable. Given the inputs you see here, induction heating saves 128 pounds of CO2 per day and over 46,899 pounds per year. This is the equivalent of removing five internal combustion engine cars from the road.

The cost savings of induction heating compared to a gas oven are often considerable too, and the difference compared to an electric oven is typically even more significant. The cost variables depend on local rates. Induction heating wastes little heat due to the direct transfer of energy to the workpiece, resulting in significant energy savings.

This calculator (Fig. 2) can be found at www.green-energy.ambrell.com, and it will enable you to input your local rates and pertinent variables.


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Fig. 2. Ambrell’s induction heating calculator


Is Induction Right for My Process?

Now that you have learned about the environmental benefits of induction heating that can result in utility savings, the question becomes: Is induction right for you? Induction is particularly ideal when you have a high-volume process that requires consistent part quality. That said, there are many scenarios where induction can be optimal.

Induction companies often offer free application testing, so reviewing your application with experienced application engineers and sending your parts in for testing is usually a great way to help you determine if induction is the right fit for your process.

For more information: Dr. Girish Dahake is Senior Vice President, Global Applications at Ambrell (www.ambrell.com) in Rochester, N.Y. He has over 25 years of induction experience and leads a worldwide team of induction application experts at Ambrell’s applications laboratories. He holds patents, has authored numerous papers and frequently presents at professional conferences. Contact Brett Daly, Ambrell’s global marketing manager, at bdaly@ambrell.com for additional information.