What types of heat transfer are used in real fire fireplaces?

Conduction is the transfer of heat through direct physical contact. The heat transfer between the domestic induction cooker and the gas stove is generated by conduction. Sometimes, when we try to control the conduction of heat, the gentleman is hypocritical, and this is what we are talking about. Due to the different heat transfer rates of different materials, we chose fabrics (such as thick woolen sweaters to slow down the heat dissipation from the body) as our choice for winter clothes and also chose a real fire fireplace as the latest home heating solution.

Conduction is a more effective method of heat transfer, but it is also slower. The denser the material, the greater the heat transfer from one location to another. When you walk barefoot on the carpet in the living room, it feels completely different from stepping on the tiles of the kitchen. But the carpet and tile floor are both at the same temperature, why does one feel colder than the other? It can be explained by different heat transfer rates: the heat emitted by the tile material from the skin is greater than the heat emitted from the carpet. This is the scientific explanation from the perspective of physics.

The same principle also applies to real fire fireplaces. We all know that the common real fire fireplace is a wood-burning fireplace, and this kind of furnace is generally made of cast iron or steel. Both have their own advantages. In terms of heat preservation ability, it is undoubtedly Cast iron real fire fireplace is better, because its heat transfer rate is slow, so the heat dissipation is naturally slow. The direct sensory impression is that this kind of stove has slow heating and long residual temperature, which is more suitable for years of endless use. .

The nature of convective heat conduction in real fire fireplaces and the particles (atoms or molecules) of two objects at different temperatures. The (average) kinetic energy of particles in hot objects is higher than that of particles in cold objects. If two particles collide, the energy will be transferred from the particle with the larger kinetic energy to the particle with the smaller kinetic energy. When two objects are in contact, many particles collide, resulting in a net heat flux from a high-temperature object to a low-temperature object. The heat flux depends on the temperature difference Δ=heat-cold. Therefore, boiling water burns more severely than hot tap water.

convection

Convection is one of the common methods in nature and real fire fireplaces with artificial heating equipment transfer heat from one object to another. This is because it is an easy-to-use and control method. The heat transferred by convection in the wood fire is directly related to the blowing speed of the wind in the outdoor fire or the degree of forced convection in the fire of a real fire fireplace. In a real fire fireplace, heat is transferred from the burning wood to the room, while cold air is drawn into the fire from the floor, which forces the warm air to be expelled and circulates heating for the room.

The so-called process of expanding and rising of the air heated by the hearth of a real fire fireplace to form a convection loop. In layman's terms, it is the time required to transfer energy to other parts of the space. Here we can understand it as the area of ​​the real fire fireplace. For the unit of heating for the whole district, you can use time instead of BTU. When the air is cooled on the ceiling and exterior walls, the air shrinks and eventually becomes denser than indoor air and sinks. A reasonably designed heating system based on real fire fireplaces generally uses natural convection, which can effectively and evenly heat the house.

Heat radiation

Real fire fireplaces can also transfer heat through radiation. This includes both visible light produced by fire and longer wavelength light, such as infrared light that is invisible to the human eye. Fire is roughly the same as solar radiation, using light radiation to generate heat. This process is also similar to the heat that the earth radiates back into space at night when it is cooling, that is, black body radiation or thermal radiation.