It is clear that in this case the dimensions of the firebox and heat exchange circuit must be at least twice as large and made of heat-resistant materials. There are also restrictions on the fuel used. In this case, we are talking about a heat exchanger for a wood-burning stove. Even peat briquettes, not to mention coal fuel, are not used for the types of stoves in question.
The designs of heat exchangers are not limited to the traditional copper pipe coil. The total number of heat exchanger models, according to the most modest estimates, is no less than a dozen and a half pieces.
The most popular and in-demand types of furnace heat exchangers include the following designs:
Tubular heat exchangers made of copper or steel pipes in moj data form of a ring or flat snake. Such systems have the highest water heating efficiency, they are easy to manufacture and install on a sauna stove. The disadvantages of the design include high sensitivity to overheating;
Box heat exchangers are made of heat-resistant sheet steel in the form of a plate container or a rectangular tank. In general, this is simply a container made of heat-resistant material, with welded pipes for connection, supply and discharge of water;
Frame heat exchangers are a rather complex structure made of steel pipes welded into a set of several registers. Structurally, this type simply copies the design of a locomotive boiler. Therefore, the structure itself is very reliable and durable, capable of withstanding prolonged overheating and high steam pressure;
Package heat exchangers are manufactured for sauna stoves by specialized enterprises. They are not manufactured by handicraft methods. They are highly efficient, but at the same time they are prone to wall burnout even with slight overheating.
If we compare the above designs, all three models, except for the package version, are efficient enough to heat water in a flowing state. The heating rate for a conventional standard heat exchanger with a channel diameter of 10-20 mm is 10 ml/оС. At a water flow rate of 20-30 mm/s, the water has time to heat up to 70-80оС at the outlet of the furnace.
Advantages and disadvantages of designs
If you make a heat exchanger with your own hands, then the most interesting thing is the types and designs. Most often, the flow part is made of a copper pipe with a diameter of 15-20 mm. The workpiece is wound on a wooden blank, couplings or couplings are pressed onto the ends, with the help of which you can connect the heat exchanger to the tank feeding the sauna stove.