Kostrzewa Twin Bio Luxury Compact NE 8 Notice Technique page 66

4. Design guidelines
66
e. Glycol requirements
Glycol might be used in KOSTRZEWA devices.
Glycol features:
• protects the installation from low temperatures and corrosion process,
• protects the system from the sediments and growth of microbiological
life,
• contains corrosion inhibitors, anti-foam agents, pH regulators, biocides,
pigments and demineralized water.
Only use glycols tested with clearly defined parameters depending on
the client's needs.
f. Example glycol parameters (-15°C)
• Glycol type: propylene
• Glycol concentration: 33%
• Crystallizing point: 15°C
• Form: homogeneous liquid without sediments
• pH value: 7.5 - 8.5
• Alkali reserve
• Density in 20 °C: 1.030g/cm³
• Kinetic viscosity in 20°C: 3.15mm2/s
• Thermal expansion: 4.73% (0-80°C)
g. Flue system installation guidelines
THE FLUE SYSTEM MUST CONFORM TO THE RELEVANT
STANDARDS AND REGULATIONS.
The flue system removes flue gas from the boiler room to the atmosphere.
The flue system creates draught determined by:
• temperature gradient between the flue gas temperature and the
ambient temperature (difference in density and pressure)
• flue length
• flue shape (bends, inclination, draught breaker etc.)
• flue cross section
• flue diameter (flue diameter must correspond to the boiler's flue
connector diameter)
• flue internal surface roughness
• flue flow capacity
• flue gas tightness (seals, grouts etc.)
• flue thermal insulation
• changes in ambient conditions (temperature, pressure fluctuations due
to the air flow, roof shape, flue location in relation to building envelope
components etc.)
Leader in pellet boilers
The diameter of the duct connecting the boiler with the flue must correspond
to the diameter of the boiler's flue connector. Do not use any reducing couplings
of the boiler's flue connector or the flue. Any transition between the flue and
the duct may include a tee with a correct combination of diameters. The flue
design must guarantee that the flue gas temperature at the entire flue length
to the outlet is higher than the dew point of the flue gas from the boiler
(dry operation). The flue and the smoke ducts must be fitted with drains or
inspection holes with sealed doors and in case of wet flue gas also with a
condensate drain valve.
Guidelines:
• in the lower range of Twin Bio Luxury Compact NE power, the flue gas
temperature may fall below 100°C, and for that reason the boilers
must be connected to moisture resistant flues (acid proof liners - steel
sheet, vitrified clay recommended); if the boiler is not connected to the
moisture resistant flue, perform required calculations or use the existing
flue data
• the connection between the boiler's flue connector and the flue must be
insulated and as short as possible, slightly upwards without sharp bends
and a minimum number of bends
• the smallest diameter or cross section of a natural draught flue and a
smoke duct must be min. 0.14 m , whereas the smallest diameter must
2
be min. 0.12 m 2 if the steel liners are used;
• horizontal flue duct length must not exceed the effective flue height
or 7 metres
Tip:
Connect the flue ducts without any loads and stresses
• seal the flue duct
• the flue must be opened upwards and lead horizontally at least 1 metre
over the roof surface (with a rain cap)
• flue diameter must be selected in accordance with the flue liner
manufacturer's requirements
• estimate cross sectional area of a circular flue is calculated using
Redtenbacher's equation:
2,6Q
A =
n√h
where:
A = flue cross section [m
]
2
Q = boiler thermal power [kcal/h], (1 kcal/h = 1,163 W);
h = flue height, dependent of building height, [m].
The formula is the same for oil-fired boilers, only that it involves a
different factor (0.033)
n = coefficient (wood n=900, gas n=1800, coke n=1600)
Twin Bio Luxury Compact NE v01 User Manual – EN 01.19