Thermal properties of wood
The efficiency will directly depend on the thermal conductivity of the material. Any owner of a private house with a stone stove knows about this nuance. The quality of combustion also depends on one more indicator - the combustion temperature. By increasing the degrees, you can heat up the water in pipes or brick walls much faster, thereby protecting your home from severe frosts.
If you put a poplar in the firebox, you can observe a very high flame, but its temperature will not exceed 500 degrees, and this is not so much for heating the room. Ash, beech and hornbeam are preferred. They burn actively, but at the same time they emit a temperature of 1000 degrees. This figure is ideal for heating a room.
Can a fire occur in a bathhouse at a high air temperature?
This is theoretically possible, but practically impossible. In order for the spontaneous ignition of the tree to begin in the bath, the air temperature must be about 200 degrees. Not a single bathhouse is capable of this, and even more so not a single person.
The record for staying in a sauna belongs to a Swede, who at a temperature of 110 degrees was able to hold out for 17 minutes. For most people, a temperature of 90 degrees is the maximum allowable. With this heating of the air, the load on the heart increases sharply and there is a chance to faint.
The bathhouse or sauna is still recommended not to be left heated above 100 degrees for a long time for reasons of fire safety. Although the ignition temperature of wood starts at 200 degrees, caution never hurts.
Criteria for choosing the type of wood, depending on the purpose
When choosing the required material, you should know a few nuances. For example, if you use ash or beech, you can raise the temperature to high values, but if you use them for a bath or a furnace, then it is very expensive and unprofitable - firewood burns quickly. For this reason, people began to use a different wood - birch. Combustion of birch firewood is accompanied by obtaining 800 degrees.
Oak and larch are also often used. Their combustion temperature ranges from 840 to 900 degrees. When there is a need to make an open fire, a fire, light logs in the grill in your summer cottage or private plot, it is advisable to use pine. It is also often used to heat a home by placing it in an oven. The combustion temperature of the material is about 610-630 degrees. But for this reason, you will have to use about half as much firewood than using birch or oak.
Features of coniferous species:
- The combustion temperature is low.
- When placed in a fire, a large amount of soot and smoke is generated.
The appearance of smoke and soot is due to the large amount of resin contained in the wood. It settles on the walls of the chimney and therefore needs to be cleaned periodically after use. Therefore, conifers are not so popular for the firebox - the cleaning process is very laborious. Such material is used only as a last resort, if there is no other option.
Also, when making a fire, it is necessary to pay attention to the moisture content of the materials, since this percentage directly affects combustion. The wetter the wood, the worse it burns. But it also creates a lot of smoke.
Popular experience shows that in order to obtain the necessary heat for heating a house, it is necessary to use firewood from beech, oak, which is felled in winter, mountain pines, birch and acacia.
The strongest flames are ash, resinous larch, maple, pine or oak, felled during the summer.
Many people prefer to burn pine - this is one of the most popular options.
Fir, chestnut and cedar produce a little less heat.
Poplar, alder, and aspen have the worst heating capacity.
From all this, we can conclude that those firewoods that are the most weighty and dense form heat best.
Which are best for the oven
Any firewood can be used as fuel. The main thing is that they are. Each region has its own preferences, depending on which trees grow in the area. Many people think that birch or alder are the best. The choice is yours.
To the bath
The choice of logs for heating a sauna depends on the design of the stove. Many people prefer:
- Alkhovye. They give a persistent heat, burn almost smokeless. There is a popular belief about their healing power;
- Birch. Burns evenly, strong heat;
- Willow. The heat transfer is low, you will need a lot of them, but the spirit in the bath will be especially light.
It is not recommended to use oak trees - they burn out for a long time, the heat is hard, and they emit a large amount of carbon monoxide. Periodically, aspen is used to clean the chimney. If the furnace is remote, the main selection criterion is heat transfer.
For home heating
Deciduous firewood has the best qualities, and they are used more often. Birch, oak, linden - any, depending on their availability and needs. The main thing is to be dry. In fireplaces, it is better to use those types that smoke less, do not "shoot".
Heating with wood can be caused both by necessity - due to the lack of another type of fuel, and by one's own desire. Logs burning in the oven create an unsurpassed atmosphere of warmth and comfort, emit a lot of heat, and for the most part provide a healing effect.
Factors affecting the burning temperature of firewood
There are several factors that contribute to combustion:
- The type of wood used for combustion.
- Moisture content of the material.
- The volume of air entering the furnace.
These are the main indicators that you need to pay special attention to, since it is on them that the efficiency of wood combustion will depend, and the temperature that can rise during the combustion process.
Humidity level
The moisture content of the wood plays a key role in firing up, therefore such an important point requires separate consideration. Any tree that has just been felled has a certain moisture content. In most cases, this figure is 50%. But in some cases it rises to 65%. And this suggests that this type of material will dry for a very long time under the influence of high temperature before igniting.
Some of the heat will only go to remove excess moisture by evaporation. For this reason, the temperature will not reach its maximum value. Heat transfer under this condition will decrease.
To get the maximum benefit, there are a few basic options you should use:
- Drying is the most suitable option. To do this, the tree is cut into small pieces, and then folded into a dry place in a shed or shed. Under natural conditions, the drying process will take approximately 1 year. And if the firewood is stored longer and lasts two summers, then their moisture content will be 20%. This is already the optimal indicator.
- The second option is less preferable - to burn what is, not paying attention to moisture. But in this situation, you will have to spend twice as much firewood to form the desired temperature. In addition, you should be prepared to clean the chimney from soot.
The better the wood is dried, the higher the combustion temperature can be taught. And the release of heat also depends on this. Heat will not work with wet wood.
Warming up process
Heating up is the heating of a separate section of wood material to a temperature sufficient to ignite the entire surface.
Usually 120 degrees are enough for heating - the wood begins to char.
After that, the process will continue when coal is formed. When heated to 250-350 degrees, the selected material will begin to decompose into its components. Then smoldering begins, but the flame does not appear yet. At this moment, the formation of smoke can be observed. As the temperature continues to rise, the level of pyrolysis gases increases - an outbreak occurs. The wood will ignite completely.
Flammability of materials
The flammability is directly influenced by the percentage of moisture that is contained in the selected rock. An important role is played by the power of the heating source, as well as the cross-section of the wood and the air flow rate.
In order for the flame to ignite faster, it is desirable to use light wood, which has a large porosity. Wet wood will ignite very slowly as it will dry out before an open fire forms.
Burning also depends on the shape of the tree - it is advisable to use a rectangle, since the circle will inflame much longer. To speed up the process, it is necessary to select a material with a small section and sharp edges. It is important to ensure that the required amount of oxygen is supplied to the heated area.
The device of the home stove also has a great influence on the burning temperature of wood and flammability. It can be made from different materials and this directly affects the combustion temperature of the materials put inside. If the stove is massive, then the firewood in it will burn almost completely, but this process will take a very long time. Great care must be taken when using. Failure to comply with safety measures can lead to a fire in the wood-burning bath at a high combustion temperature of the stove.
In a stove stove, firewood often does not burn completely due to the fact that it cools down quickly
The stove-stove, made of steel sheet, cools down quickly, while the heat is distributed over the surrounding space, but first it will pass from the combustion zone to the walls, and only then to the room.
Combustion process
Observing the operation of the oven, one might think about why the supplied air does not affect the color of the resulting flame. The oxygen must be chemically active and give the soot a bright color that can even turn white. But this phenomenon can be easily explained, because the size of the particle also affects the temperature. The smaller it is, the lower the temperature will be. Therefore, small hot particles form the same temperature as the gas that surrounds them. It should also be noted that each type of wood has a certain heat transfer. To find out these numbers, you can study the table, which shows all the thermal conductivity indicators for each type of material.
How to prepare firewood
Firewood harvesting usually begins in late autumn or early winter, before a permanent snow cover is established. The felled trunks are left on the plots for primary drying. After some time, usually in winter or early spring, firewood is removed from the forest. This is due to the fact that during this period no agricultural work is carried out and the frozen ground allows you to load more weight on the vehicle.
But this is the traditional order. Now, due to the high level of development of technology, firewood can be harvested all year round. Enterprising people can bring you already sawn and chopped firewood any day for a reasonable fee.
Saw the delivered log into pieces suitable for the size of your firebox. After that, the resulting decks are split into logs. Decks with a cross section of more than 200 centimeters are pricked with a cleaver, the rest - with an ordinary ax.
The decks are split into logs so that the cross-section of the resulting log is about 80 square cm. Such firewood will burn for a rather long time in a sauna stove and emit more heat. Smaller logs are used for kindling.
woodpile
Chopped logs are stacked in a woodpile. It is intended not only for storing fuel, but also for drying firewood. A good woodpile will be located in an open area blown by the wind, but under a canopy that protects the wood from precipitation.
The bottom row of woodpile logs is laid on logs - long poles that prevent firewood from contact with wet soil.
Drying of wood to an acceptable moisture content takes about a year. In addition, wood in logs dries much faster than in logs. Chopped firewood reaches an acceptable moisture content already in three months of summer. When the woodpile is dried for a year, it will have a moisture content of 15 percent, which is ideal for combustion.
Combustion temperature measurement
It is very difficult to measure the combustion temperature at home. A regular thermometer will not work here. Of course, "by eye" it will also not be possible to determine the correct combustion temperature of a certain material. To carry out such research, you need to purchase a special device called a pyrometer.
But you need to know that a high burning temperature of firewood in the stove will not mean that they will generate the required amount of heat. Therefore, you should also take care of quality equipment. In good stoves, it is possible to artificially reduce the supply of oxygen to the wood. Thus, it is possible to achieve an increase in the combustion temperature and a decrease in heat transfer.
Since it is very difficult, expensive, and sometimes impossible to measure the combustion temperature of different firewoods at home, you can rely on official data. All indicators have long been calculated in laboratory conditions by experts, through comparative analysis. To obtain the necessary results, the wood was thoroughly dried before testing - it was brought to an optimal state for experiments with open fire.
Thermal conductivity of materials:
| Wood species | Calorific value in calories |
| Birch | 4968 |
| Pine | 4952 |
| Spruce | 4860 |
| Alder | 5050 |
| Aspen | 4950 |
The concept of "burning temperature of wood" does not quite correctly reflect the main characteristic. It is necessary to pay more attention to the ability to generate heat. The unit of measurement for such a parameter - calories - is heat energy, which heats 1 gram of ordinary water by 1 degree.
Heating capacity
In practice, a person should be interested in the heat output of the selected material. This is the temperature that can be reached by burning a certain type of wood.
Firewood heat output table:
| Breed | Heating capacity in percent | Temperature in Celsius |
| Beech and ash | 87 | 1044 |
| Hornbeam | 85 | 1020 |
| Winter oak | 75 | 900 |
| Larch | 72 | 865 |
| Summer oak | 70 | 840 |
| Birch | 68 | 816 |
| Fir | 63 | 756 |
| Acacia | 59 | 708 |
| Linden | 55 | 660 |
| Pine | 52 | 624 |
| Aspen | 51 | 612 |
| Alder | 46 | 552 |
| Poplar | 39 | 468 |
Subtleties and nuances
- Worst of all, if you have raw aspen firewood available. This type of wood generates a small amount of heat, so aspen firewood will be very difficult to ignite. The logs will smolder slowly when exposed to temperature, giving off very little heat.
- A good option for quick kindling of raw logs is birch or spruce. Despite the fact that these types of trees emit a lot of soot and soot during combustion, they are optimal for quick kindling. Fire is caught on chips and birch bark literally in a matter of seconds.
- The original way of quickly drying wood was invented by our ancestors. Salt should be sprinkled on damp firewood in large quantities. The salt will draw out some of the moisture and the wood will become usable.
- If we kindle a fire in nature and there are flammable liquids in our arsenal, for example, diesel fuel, gasoline, kerosene, then it is quite possible to water the chips with these compounds.If you want to use flammable liquids in the oven, you can moisten a rag with them and put it between the logs. The characteristic smell from such liquids will disappear quickly enough after lighting a fire.
- Some experts recommend putting an empty vegetable oil bottle in the firebox. With its help, it will be possible to quickly obtain the required amount of fire.
Note that firewood is always bought raw. It is best to do this in winter, stocking up for the next season, when equipment easily enters the forest. In this case, before use, the firewood will lie with you for a whole year. They must be stored in a woodpile, protected from precipitation and blown by the wind.
As you can see, there are no special difficulties with kindling raw firewood, the main thing is to approach this issue thoughtfully, to carry out the preparatory work with high quality. With a little patience, you will have a nice intense fire that gives you warmth.
Practical advice
- If the house is heated by a stove and during the combustion process it smells of damp wood, then you must immediately examine your equipment. Perhaps the tightness and integrity are broken somewhere.
- A large amount of acids are released during combustion, therefore the chimney should be built from reliable materials that are able to resist aggressive environments.
- If wood with resin is used, then thoroughly clean the chimney after use.
- To heat stones, for example, in a steam room, it is advisable to use wood that burns weakly and emit a large amount of heat.
- For rapid heating of the steam room, a material with a high combustion temperature is used. In this case, the air supply to the furnace must be increased.
Having studied the material, you can understand what temperature of burning firewood is needed for the most efficient heating of the room.
conclusions
From all of the above, the following conclusions can be drawn:
- The most popular firewood for a fire are: pine, birch, alder - due to the massive growth of trees of these species and their ubiquitous distribution. Suitable for both cooking and heating.
- Low-quality firewood that can be used when there are no other options are aspen, willow, poplar. Perfect for boiling water or quick cooking.
- In an extreme case, when there are no trees, dried tall forbs or dung will help out.
- The most unsuitable firewood for a fire is spruce and fir.
- Hereinafter - for wood with a moisture content of 12%, which is quite consistent with the not very old dry wood.
Fruit trees for flavor
Of course, no one will just grow fruit trees for the sole purpose of using them later for firewood. However, the site still has an apple, pear, plum or cherry. Over the course of some time, you can collect a lot of branches and twigs, which you can put into the combustion chamber. Some people start fires right away, but where it will be right to carefully cut them and put them in a woodpile. They are more suitable for kindling a sauna, since, along with a beautiful and even heat, the combustion of firewood gives not heavy steam, accompanied by a pleasant, delicate aroma.
Cutting and chopping wood does not cost anything, the apple tree is considered the leader in terms of heat generation, and there is almost no smoke. But this choice is rather beautiful.
