What is a condensing boiler?

A condensing boiler is an improvement on a standard boiler system, such as a supercharger for a car engine, or the turbo system. The use of condensing boilers allows a huge part of this latent heat to be recovered, which considerably reduces the combustion gases' temperature, lowering them to values ​​of the order of 45°C or lower, thus limiting the emissions of polluting gases.

For a condensing boiler to work at maximum efficiency, the return water temperature will have to be lower than the fumes' dew point temperature. Thus, the most suitable heating system for its use is underfloor heating. However, the performance is also improved compared to that of a traditional boiler in a radiator circuit.

The biggest problem in the design of these boilers is the possible corrosion that the exchanger can suffer when it comes into contact with the acids produced in the condensation, which is why materials such as aluminium or aluminium are used in their manufacture. Besides, we must bear in mind that we have to connect the condensate outlet to a drain in which these should be treated before sending them to the sewer network.

Likewise, the combustion products when they are outside the combustion chamber, allow the heat to the water in the boiler. In the case of fumes, they are produced by the heat that is neglected by the combustion products, the same that come out through the chimney, which is composed of sensible heat losses that depend exclusively on the temperature of the fumes, a percentage of CO2, losses due to unburned carbon products and losses due to disposal, where heat is produced through periods of boiler shutdown.

Subsequently, the fumes come out at temperatures between 30-100°C, which causes the fan to generate sufficient pressure to overcome the smoke duct. For this reason, the vents must be designed using optimal materials so that they can resist the action exerted by condensates.