Flue gas heat exchanger for steam boilers

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.

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.

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.

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.

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.

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.