Flue gas heat exchangers for hot water 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 return water.

If a separate water circuit is available, the use of condensing technology can be meaningfully supplemented. A stainless steel condensing heat exchanger partially reduces the flue gas temperature to below the dewpoint – the flue gas condenses. The condensation heat that is released preheats the separate water circuit.

The effective use of the recovered waste heat allows for fuel savings of up to 7%. When condensing technology is used, savings of up to 15% can even be achieved. 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 variant of the flue gas or condensing heating 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 ready-to-connect stand-alone variant with optional bypass – recommended when using dual firing.