barbas ENERGA 70-55 TUNNEL, Installation Instructions Manual

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47
ENERGA 70-55 TUNNEL
8.2 OUTPUT
In practice, combustion is all about loss. This entails:
• Loss through excess heat leaving the chimney, rather than going into the room.
• Loss through insuffi cient combustion, such as CO (carbon monoxide) and soot
particles.
• Loss through excessive unburnt fuel in the ash.
The rate at which fuel can burn completely is called the output. A well-stoked fi tted fi re
achieves output of 75% and thus falls into the category of high-output/low emissions
built-in fi res. This means that you benefi t directly by using less wood to achieve the
same level of heat. The environment benefi ts as well: a well-stoked, high-output
appliance means less pollution and fewer odours.
Adverse effects on the output are:
• Burning the fi re with the door open. A warm chimney works in the same way as
an extractor. When the door is open, the chimney draws in much more air than is
necessary for combustion. This relatively cool air cools down the fi re.
• Excessive chimney draught. The combustion air does not reach the fuel, but leaves
the appliance via the chimney. The fi re cools and the combustion quality decreases.
• Using too much wood. This is a problem if your built-in fi re is too small. In that case,
it becomes overloaded and burns more wood than heat emitted. In this case too the
fuel cannot burn completely. More to the point, there is not enough air to mix with the
fl ames. This has an extra impact on the environment.
• Admitting too much air under the fuel (combustion air supply slider is fully over to the
“ + ” position).
Combustion is raised to high intensity (like a blacksmith’s fi re). Combustion really
needs time. If combustion is too intense, there is insuffi cient time for the built-in fi re
to radiate all the heat. The chimney will become excessively hot and the same will be
true of the escaping smoke. This heat is thus lost.