Expansion Noises; The Chemistry Of Wood; Contribution To Environmental Protection; Evaluating The Combustion Quality - HASE Luno B.13 Mode D'emploi

plete as possible chemical
reaction of the wood gases with the oxygen in the combustion
air. In your Hase stove, the combustion air is pre-heated and
guided into the fi re box via wide air inlet openings, so that at
high temperatures, there is a good, thorough mixing of the
gases with the air. An important variable in any combustion
phase is the amount of combustion air. Too little air leads to
an oxygen defi ciency and incomplete combustion, while too
much air reduces the fi re box temperature and thus the effi ci-
ency. Incomplete combustion can generate air pollutants such
as dust, carbon monoxide, and hydrocarbons.
Burn-off
Fig. 8

18.4 Expansion Noises

Steel expands upon heating and contracts as it cools. These
movements occur during the warming up and cooling down
phases, as well as when adding fuel. They can cause your stove
to emit audible expansion sounds. However, the design and
construction of your stove takes this into account and prevents
this physical process from damaging the stove.
64

19. The Chemistry of Wood

Wood predominantly consists of the elements carbon, hy-
drogen, and oxygen. It contains virtually no environmentally
hazardous substances such as sulphur, chloride and heavy
metals. As a result, complete wood combustion produces
mainly carbon dioxide and water vapour as the primary gase-
ous products as well as a small quantity of wood ash as the
solid combustion residue. On the other hand, incomplete
combustion can generate a number of pollutant substances,
such as carbon monoxide, acetic acid, phenols, methanol,
formaldehyde, soot, and tar.

20. Contribution to Environmental Protection

Whether your Luno burns in an environmentally-friendly or
environmentally hazardous manner depends to a large extent
Degasifi cation
on how you operate it and the type of fuel you use (see Sec-
tion 11, „The Right Fuel").
Therefore, use only dry wood; hardwoods such as birch and
beech are most suitable.
Only use small pieces of wood to light the fi re. They burn fa-
Drying
ster than large logs and as a result, the temperature required
for complete combustion is reached more quickly.
For continuous heating, adding smaller quantities of wood
more frequently is more effi cient and more ecological.

21. Evaluating the Combustion Quality

The following characteristics can help you easily evaluate the
quality of the combustion:
– Colour and composition of the ash
If the combustion process is clean and effi cient, the
result is a fi ne white ash. Dark colouration indicates that
the ash contains charcoal residue; in this case, the burn-off
phase was incomplete.
– The colour of the fl ue gases emitted at the chimney pot
Here, the following applies: the more invisible the fl ue
gases exiting the chimney, the better the combustion quali-
ty.
During the transitional seasons (spring/autumn), outdoor
temperatures above 16°C can impair the chimney draught. If
a draught cannot be created at these temperatures by rapidly
burning paper or thin wood shavings (quick fi re), you should
refrain from lighting the stove.

22. Wood Moisture Content and Calorific Value

Rule of thumb: the more damp the wood, the lower the ca-
lorifi c value.
The calorifi c value of the wood depends largely on the wood
moisture content. The more
moisture the wood contains, the more energy expended to
evaporate it during the combustion
phase; this energy is then lost. The more damp the wood, the
lower its calorifi c value.
An example: freshly cut wood has a moisture content of ap-
prox. 50% and a calorifi c value of around 2.3 kWh/kg; in con-
trast, wood which has been effi ciently air-dried has a moisture
content of approx. 15% and a calorifi c value of around 4.3
kWh/kg.
Accordingly, if you burn very moist wood, you will have about
half the thermal output with the same quantity of wood. Fur-
thermore, burning moist wood results in substantial soot