A household high-efficiency boiler contains a flue gas sensor. A large smoke gas sensor.
A flue gas sensor is a heat exchanger that cools down the flue gas below the dew point to recover the evaporative heat of the water vapor into the flue for useful use.
The cooling can happen indirectly with a heat exchanger, but also directly through the injection of water into flue gas. Injection of water saturates the flue gas with water, creating a visible smoke plume.
The condensation of water releases two gigajoule heat per cubic meter of condensed water. The heat is useful for heat distribution. The return will increase by 15%.
In addition, condensed hot water is sometimes useful in the process. If the fuel contains compounds of sulfur or chlorine, the flue gas contains sulfur dioxide or hydrogen chloride and which first condense as azeotrope. Therefore, the flue gas sensor must be resistant to corrosion, for example, using stainless steel AISI 316L or graphite.
A flue gas sensor is especially useful in high moisture fuels, such as natural gas, biomass and household waste. An example is the Waste Energy Company in Amsterdam, which warms up with the flue gas sensor condensate. AVI Moerdijk also applies a flue gas sensor. Smoke gas condensation is only useful if there is also a useful buyer for the low temperature hot water. The buyer's return is well below 55 ° C, as in Copenhagen.
Smoke gas sensors are widely used in domestic gas boilers on natural gas, the so-called high efficiency boilers. Since the yield of a gas boiler on agreement is involved in the lower combustion value of natural gas and allows a flue gas sensor to also use the heat of condensation, thus the upper combustion value, a yield above 100% is possible. For example, a HR107 boiler has 107% efficiency based on the lower combustion value.
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