technology Page 50
- The exhaust gas temperatures
of conventional boiler systems are much higher than those of condensing boiler
systems. That means that the exhaust gases of conventional systems tend to
automatically move up because of their natural buoyancy.
- In order to remove
the exhaust gases of condensing boiler systems, mechanical support installations
are necessary (with the exception of pulsation - condensing boilers): there
either is a fan installed in the exhaust gas pipe which sucks the exhaust
gases out or there is a blower integrated in the system which is pressing
the exhaust gases out.
In the exhaust gas pipe
there has to be a place where the condensate can be collected. Furthermore,
from this collection point on the exhaust gas pipe has to have a constant downward
inclination, so that the condensate can not collect itself in another place.
- In the case of the concentric
chimney arrangement, the exhaust gas pipe is completely surrounded by inflowing
combustion air. With the parallel chimney arrangement this is not the case.
- Diagram: Concentric
and parallel exhaust gas systems
The combustion air supply
pipes and/or the exhaust gas pipes have to be designed so that in the exhaust
gas pipes an over-pressure is being created whereas in the combustion air supply
pipes a low-pressure (see the diagram above: in the area where supply air is
flowing in, there has to be a low-pressure).