Heat recovery from hot flue gasses

exodraft systems

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Exodraft systems has a clear ambition to position itself as the market leader as a total supplier of heat recovery systems in the same way that its parent company exodraft a/s has been the market leader of mechanical chimney draughts since 1957. What most people aren’t aware of is that when you pull out all the heat from a chimney system to recover it, the temperature of the chimney drops, leading to increased resistance and poorer draught. Therefore, a mechanical draught system is needed to ensure a predictable and a uniform production and here we can combine our heat recovery expertise with more than 60 years of experience as the market leader in mechanical chimney draught solutions. You get the best of both worlds: Optimal chimney draught and high-efficiency heat recovery.

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Heat recovery is a good idea and benefits both your wallet and the environment.

With the help of gas boilers from exodraft, the excess heat from your hot flue gasses can be recovered, made into hot water and find further uses for it in your company.

The possibilities involve reintegrating of the waste heat in the original process or other internal uses through integrating with other processes, room heating, cleaning or bath facilities.

In case you end up recovering more heat than you need in your company, you can earn money on transferring your excess heat to a third-part as a district heating plant.

Flue gas as an energy source

Most of the companies in the manufacturing industry has processes that lead to flue gas emissions. What most people aren’t aware of, is that hot flue gasses are filled with useful energies. These energies often end up going up through the chimney instead of being useful for the company. exodraft systems wants to end this tendency which is why we, with our gas boilers, offer the companies to recover the excess energy from their flue gasses and use it – in form of hot water – to different kinds of useful purposes.

Where can the recovered energy be used?

Pros with an exodraft heat recovery system.

  • Quick ROI – usually 2-3 years
  • The most compact and effective heat recovery unit on the market
  • Easy maintenance because of removable heat exchangers
  • Our bypass-system ensure a stable and continuous use (No down-time for your production)
  • One dedicated contact person to ensure the best possible customer service
  • A PLC-control makes onsite- and remote controlling and monitoring possible
  • Can be installed in both a horizontal and vertical position
  • Short delivery time typically 3-4 months

Get to know more about exodraft’s heat recovery systems at

How does flue gas heat exchanger work?

A flue gas heat exchanger is a heat exchanger designed to extract the energy in hot flue gasses and convert it – typically – for warm water. By adding cold water to the exchanger and heat it up with a throughput of hot flue gasses, the water in the exchanger will absorb the heat from flue gasses. The results are that the cold water is coming out on the other side of the heat exchanger as hot water and – opposite the flue gasses are being cooled down in their passage through the heat exchanger, because they give off an amount of heat to the water.

From process to district heating

If you don’t need the excess heat that you heat exchanger generates, it can be sold to the district heating at a price that’s advantageous for both parties. You will get an extra income by selling heat to the district heating producer and the district heating plant gets the excess heat to a cheaper price, comparing to what it would cost to produce the heat by using gas, oil or straws.

In addition, most district heating plants are interested in the sustainable and environmentally friendly profile, that follows with reusing excess heat.


With headquarters in Ferritslev, Funen, Denmark and factories in both Sweden and China, FJ Industries has been specializing in the production of sintered metal items for almost thirty years.

The production of sintered metal items is a lengthy process in which metal powder is subjected to massive hydraulic pressure in order to compress it into metal components that are subsequently heat treated in a tunnel oven.

During sintering in the tunnel oven, large amounts of heat are released in the form of flue gasses, and precisely this heat is, what FJ Industries along with exodraft saw an opportunity to reuse. By reusing waste heat from flue gasses, FJ Industries could reduce their CO2 emissions significantly – while also reducing their energy costs considerably.

The heat recovery solution provided by exodraft converts the hot flue gasses into hot water which is subsequently used to not only heat FJ Industries’ premises, but also to heat bathwater and water for general purposes.

exodraft’s turn-key solution meant handling the company’s chimney structure, installing a chimney fan for draught control, running water pipes and doing plumbing work, as well as managing the heat recovery system via PLC. According to the CEO of FJ Industries, Lars Wildenschild, the implementation and the collaboration with exodraft went smoothly.

 “We have been met with great professionalism from exodraft, along with great flexibility, so the system we’ve installed accurately fits our needs. Our results show that we have actual savings of about 2,700 euros a month – which means that the solution will have paid itself off in about 2½ years.”

Included in the solution, FJ Industries also has the option of monitoring their heat recovery continuously via a screen display, affording them a clear overview of how much heat has been recovered and how much money has been saved.

All in all, the heat recovery solution from exodraft leaves FJ Industries a more efficient and greener company.

Visit for more information on heat recovery and how it can benefit your company.

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