Paliva a energie

Wood

DřevoWe recommend that wood for heating purposes is as dry as possible. Maximum power output and the longest possible life-span of the boiler is obtained if you use wood that has been in storage for at least 2 years. In the graph below, the energy contents of wood, with respect to water contents is shown. The energy contents decline very rapidly with increased water contents.

Example:
Wood with 12 - 20% water contents has got the specific energy 4 kWh / 1kg wood
Wood with 50% water contents has got the specific energy 2 kWh / 1 kg wood

Dependence of the fuel heating value on water content in wood
Dependence of the fuel heating value on water content in wood
Type of wood energy contents in 1 kg
kcal  kJoule  kWH 
spruce 3900 16250 4,5
pine 3800 15800 4,4
birch 3750 15500 4,3
oak 3600 15100 4,2
beech 3450 14400 4,0

Fresh wood heats and burns badly, smokes extensively, and markedly shortens the life-span of the boiler and chimney. The power output from the boiler decreases up to 50% and the fuel consumption doubles.

Brown coal

Hnědé uhlí The required fuel for our boilers is brown coal of walnut size. Alternative fuels are e.g. briquettes. We recommend that coal for heating is less homogeneous and has got low sulphur contents. Smaller grained fuel types should only be put on the cinders, and only in small amounts.

Briquettes from wood and from straw

Dřevěné brikety a brikety z obilné a řepkové slámy Ecological briquettes from wood are manufactured from wooden waste through pressing the contents together, without chemical additives. There are lůot of producers in Czech Republic but the quality of briquets differes. Good quality briquets do not split during burning. Splitting briquts can be burned only mixing with log wood or brown coal. Never burn them separately. The splitting briquets choke the nozzle or rotating grate.

Pellets

Pelety Pellets are a new type of fuel produced via a similar procedure as wooden briquettes from waste wood, i.e. by pressing. White pellets, made from soft wood without bark, are considered pellets of quality.
For the Atmos boilers, pellets of the diameter O 6-9 mm are used.

Other pellets made from cereal straw or sorrel are an option for the future. However, it is necessary to develop new appliances for such fuels, on which we are working.

Comparison of costs of heating with various fuel types (as at 1.1.2008)

Fuel Mean fuel heating value Mean fuel price 1.11.2008 Mean efficiency and type of boiler used Annual fuel consumption (consumption = 120 GJ and heated space volume = 370m3) Total costs of a heating season in CZK
Wood 14,8 MJ/kg 500 ,- CZK/
piled cubic meter
ATMOS gasifying boiler
(85% efficiency)
9,5 t
21 piled cubic meters
10.500,-
Classic boiler (65% efficiency) 12,5
28 piled cubic meters
14.000,-
Brown coal 18 MJ/kg 2800-3400 CZK/t ATMOS gasifying boiler
(85% efficiency)
7,9 t 22.120 - 26.860,-
Classic boiler for other fuel (65%) 10,3 28.840 - 35.020,-
Pellets 18 MJ/kg 3000-4500 CZK/t ATMOS gasifying boiler
(91% efficiency)
7,4 t 22.200 - 33.300,-
Wooden briquettes 18 MJ/kg 3000-4500 CZK/t ATMOS gasifying boiler
(85% efficiency)
7,9 t 23.700 - 35.550,-
Classic boiler (65% efficiency) 10,3 t 30.900 - 46.350,-
Natural gas 33,7 MJ/m3 1253 CZK/MWh
13,17 CZK/m3
Condensation boiler
(105% efficiency)
3390 m3 44.646,-
Classic boiler (90% efficiency) 3960 m3 52.153,-
Accumulation electricity 3,6 MJ/kWh 1,66 CZK/kWh 98% 34 010 kWh 56.457,-
Direct heating electricity 3,6 MJ/kWh 2,16 CZK/kWh 99% 33 670 kWh 72.727,-
Extra LTO (light fuel oil 42 MJ/kg 15 - 19 CZK/kg 90% 3180 kg 47.700 - 60.420,-
Propane-butane 46 MJ/kg 17 - 23 CZK/kg 90% 2900 kg 49.300 - 66.700,-

Other fees

Electricity (direct heating, accumulation) Monthly bill according to circuit breaker rating (189,- až 508,- CZK)
Natural gas Monthly bill according to selected consumption (86,- až 202,- CZK)
Propane-butane Regular pressure vessel inspections
Brown coal Ash collection fee

The real costs of heating of gasification boilers are in practise even lower then non-gasification boilers. It is caused by easy regulating way of gasification boilers.