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Why Hot Oil Heater Film Temperature Matters

When choosing a hot oil heater, film temperature is a crucial factor that is often overlooked. Many consumers focus on aspects like efficiency, burner turn down, and controls, but neglect the importance of film temperature.

So, why is film temperature critical for industrial heating? And why should plant managers consider it when evaluating hot oil heating systems? Here are a few key reasons to pay close attention to film temperature when selecting a hot oil heater for your plant.

Film Temperature Impacts the Type of Thermal Fluid Required

The film temperature in a heater that has space between the tubes, such as Enerquip’s Serpentine Coil Thermal Fluid Heater, is typically 50oF higher than the operating temperature. Most other industrial heater designs on the market use helical coils, which do not have space between the tubes. This lack of space causes uneven heat absorption in the pipe itself, creating a higher film temperature.  The film temperature in a helical coil heater is typically 100oF higher than the operating temperature. So what does this mean?

It means that with a helical coil heater, you will most likely need to select a more expensive thermal heating fluid. If you are operating at 500oF, in a helical coil heater your film temperature will be 600oF or higher, requiring you to use a much higher grade fluid than you would need if you were utilizing a serpentine coil heater like those we manufacture here at Enerquip.

At 550oF film temperature, you can run a fluid in the $10-15/gallon range, but in the 600-650oF film temperature range you will need a synthetic fluid in the $40-55/gallon price range. This can have a significant impact when it comes to your facility’s expenses.

  • High film temperature 4,000 Gallon System x $55 per gallon of heating fluid = $220,000
  • Lower film temperature 4,000 Gallon System x $15 per gallon of heating fluid = $60,000

That is a $160,000 savings as a result of using a thermal fluid heater with a lower film temperature! Obviously, this can vary depending on which brand of fluid you select, but you can see how it adds up!

Film Temperature Impacts Thermal Fluid Life

The second aspect of having a lower film temperature is that the thermal heating fluid you select will last much longer than it would in a heater with a higher film temperature. The rule of thumb from fluid suppliers is that for every 10oC (18oF) increase in film temperature, the degradation rate in the fluid will double. Since the film temperature in an Enerquip hot oil heater with a serpentine coil is 50oF lower than those with a helical coil, you will see significantly less degradation in fluid.

As a result, many of our heaters are running with the same initial fill of fluid for 15-20 years, well past the estimated life of the heat transfer fluid!

Save Money Now and In the Future With Lower Hot Oil Heater Film Temperatures

There are many benefits that come from implementing thermal fluid heaters from Enerquip in your facility. While mechanical benefits such as high efficiency, ease of repair, robust coil design, large combustion chamber, and longer coil life are all very important, perhaps one of the most significant benefits is the heater’s lower film temperature.

Interested in learning more about how our heaters with low film temperatures can help to save your facility money in the long- and short term? Give us a call today at (833) 516-6888 or contact us online for more information or to request a quote.

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