The best solid fuel boilers for long burning

The model with the KT-2E index is included in the cohort of the most economical solid fuel boilers produced by the east european company Altep. In addition, it is omnivorous to various types of fuel: the boiler works on firewood, coal, sawdust and peat briquettes, wood waste and lump peat.

The housing and heat exchanger of the junior representative of the 17 kW series are made of high-quality boiler steel with a thickness of about 6 mm. It boasts resistance to high temperatures, and is also designed for long-term operation. The convection part of the boiler is a four-way heat exchanger with horizontal water shelves. This design ensures high efficiency of heat transfer.

The laying of raw materials in the furnace chamber of the boiler is carried out manually, as well as the adjustment of the draft — the mission of controlling the air supply is assigned to the mechanical handles located on the left side of the model body. For the convenience of loading bulk fuels and cleaning the chamber, the loading neck is made at a small angle.

Gorenje duration on one fuel tab can vary from 8 to 48 hours (it all depends on the type of raw material and its quality). The highest productivity is achieved when using anthracite. Another important plus of the KT-2E boiler line is a wide range of capacities, so that the required option can be selected both for household needs and for heating large industrial premises (up to 960 m², if we are talking about a 120 kW model).

The homeland of the STROPUVA S20 solid fuel boiler is Lithuania. It served as a role model for many east european heating devices, while in terms of efficiency (about 91.6%), the S20 model is still a cut above its peers.

The secret of the boiler's high efficiency lies in the implemented know-how on fuel combustion: it is ignited and burns in the surface layer, and not from below, as in traditional solid fuel models. This method of gorenje is realized thanks to the telescopic distribution of air — as the fuel burns out, the flame centre gradually shifts downwards.

Structurally, the STROPUVA S20 consists of two steel cylinders (one inside the other), in between which there is a coolant. One load of firewood into the model's furnace (up to 50 kg at a time) is enough for a 30-hour marathon of their gorenje. The boiler maintains the set temperature of the coolant by changing the air supply and, accordingly, the intensity of fuel combustion using a bimetallic thrust regulator.

With a power of 20 kW, the model is suitable for heating rooms with a total area of 100 to 200 m². It will need to be cleaned of ash less than twice a month, besides, the boiler is originally designed to work without using electricity. The manufacturer's model range also includes the STROPUVA S20 U boiler, a universal modification of the device that can use wood chips, coal, anthracite, sawdust and peat briquettes as fuel.

The "Gorenje" boiler with the east european pedigree Buran 20 is used for heating structures with a total area of about 100 m². It functions on the principle of upper combustion — fuel is burned in a thin upper layer, and as it burns out, the fire gradually descends.

A similar gorenje principle provides up to 30 hours of autonomous operation of the boiler on one wood tab. When using coal, sawdust or peat briquettes as fuel, the specified time can be increased to 2 days, and when loading coal — up to 5 days in a row. Heated air is supplied to the upper fuel layer from a special chamber. Then the air distributor gradually descends and always stays at the level of the burning fuel.

The operational data of the boiler provide heating the coolant to a temperature of 90 °C at a maximum pressure in the heating circuit at 1.5 bar. In emergency situations, namely with a strong increase in pressure, the boiler will not explode, but will shrink inward. A distinctive feature of the early versions of the model (until 2017) was the absence of a bottom, but in the new generation of Buran 20 it already exists.

An important difference between the boiler and its analogues is the presence of a large middle door, which allows you to load fuel as tightly as possible. Convenience in handling the model is also added by a movable air heating chamber, which ensures easy and quick cleaning of the boiler from sticking deposits. Finally, it is worth noting the fact that the Buran 20 is a non-volatile boiler, but instead of a thermomechanical regulator, it can be equipped with an electronic control unit with a boost fan, which, in turn, will require connection to the power supply network.