HEAT OUTPUT OF THE STOVE
By using a rational design of the furnace and its correct equipment, it is possible to reduce its weight and size, achieving the same or even greater thermal efficiency than in the case of a furnace with a large mass but with a defective structure.. With. Due to the inevitable heat loss during the discharge of flue gases, we cannot achieve such a furnace structure, so that all the heat obtained from burning coal in it is advantageously used to heat the room.
The heat efficiency of a furnace is determined by the ratio of the furnace heating surface to its volume.
In order to obtain good thermal efficiency of the furnace, the outer walls should be built of such material, so that they can absorb the maximum heat from the combustion gases. The thickness of the walls should be this, so that all the heat obtained during combustion can be accumulated and then gradually transferred to the air surrounding the stove in the heated room.
Thus, the heat balance of the furnace consists of revenue, i.e.. from the heat from the energy generated by the combustion of the fuel and from the expense, which it consists of:
1) the heat used to heat the room,
2) heat flowing into the chimney,
3) heat lost due to faulty mechanical or chemical combustion of the fuel in the furnace.
Sure it is, that with a rational modern furnace design, it will be about this, that the expense is wasted, listed in points 2 i 3, reduced to a minimum in favor of the effective expense used to heat the room.
The ratio of effective heat dissipation to revenue expressed as a percentage is called the furnace efficiency.
The basic principle of the construction of a modern furnace should be this arrangement of the channels, that even the smallest part of the furnace mass is heated and that the accumulated heat is released to the room by radiation or convection through the entire heated surface of the furnace.
Black smoke coming out of the chimney is evidence, that fuel combustion is incomplete. The smoke contains a lot of tiny unburned carbon particles, which fly uselessly into the air polluting it.
During combustion, the fuel combines with the oxygen in the air to form carbon dioxide. With good air supply, providing the necessary amount of oxygen for complete combustion of the fuel, we get white or bluish smoke, and the smoke may contain at most particles of non-flammable substances.
With poor oxygen supply, due to bad thrust, that is, a small pressure difference necessary to overcome the resistance caused by the flowing gases, not carbon dioxide is formed during combustion, but carbon monoxide, poison gas, which may be the cause of the death of residents as a result of smoke. Therefore, the correct design of the furnace is very important, ensuring good draft and air supply during the combustion process.
Unburned fuel particles, that did not go down the chimney, but they settled on the inside walls of the stove and the flue pipe, we call soot. The soot layer obstructs heat transfer through the walls of the furnace and is often the cause of furnace smoke.