Flue gas heat exchanger for steam boilers
Flue gas heat exchanger for steam boilers
Flue gas heat exchanger for steam boilers


Flue gas heat exchanger for steam boilers

With the effective recovery of flue gas heat, you can save up to 14% on fuel and, at the same time, reduce emissions. A flue gas heat exchanger, also called an economiser, is part of the standard equipment for energy-optimised and environmentally friendly boiler operation.

At a glance

  • Effective heat recovery and reduction of flue gas losses
  • Maximum efficiency gain when using condensing technology
  • Fuel savings of up to 7%, or up to 14% when using an additional downstream condensing heat exchanger
  • Intelligent control for a long service life and high level of efficiency
  • Compactly integrated into the boiler or as a stand-alone version for simple retrofitting
  • Feed water cooling or combustion air preheating as alternatives to the condensing heat exchanger

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Effective waste heat recovery

The flue gas flows at the boiler outlet inherently have heat potential at a high temperature level. A flue gas heat exchanger is great to use in order to prevent unnecessary flue gas losses. This efficiency component extracts heat from the hot flue gas and, in return, preheats feed water – this, in turn, reduces the fuel expenses for steam generation.

Maximum efficiency gain when using condensing technology

A condensing heat exchanger not only makes better use of the heat from the flue gases. The water that is produced during the combustion process is also condensed. The energy that is released preheats cold fresh water, for example. Alternatively, the heat is also used to preheat the water for other processes or to support heating applications.

High fuel savings up to 14%

The effective use of the recovered waste heat allows for fuel savings of up to 7%. Combined with the use of condensing technology, the savings potential is increased by an additional 7%. Thanks to the significantly lower fuel costs, the flue gas heat exchanger usually amortises within a short time.

Intelligent control for a long service life and efficiency

In conjunction with the controls from Bosch, the boilers can be regulated and optimally operated based on the load of the consumers. Controlling the system guarantees a continuously high level of efficiency and a long service life.

Compactly integrated or easy to retrofit

The integrated flue gas heat exchanger is installed in the exhaust chamber ex works as part of the boiler, is connected on the water side and is ready for immediate use. Also available as a stand-alone version which can be easily retrofitted. Bosch also provides the stainless steel condensing heat exchanger as a separate, ready-to-connect module.

Alternative efficiency solutions for the condensing heat exchanger

In addition to the condensing heat exchanger, there are additional efficiency-boosting options in combination with an economiser. Together with the attractively priced feed water cooler, the efficiency can be increased by up to 8.6%. Another alternative with a potential increase in efficiency of up to 9% is the combustion air preheating.