The functions of a microchannel heat exchanger are quite numerous and important. With the help of a heat exchanger, the cold heat carrier receives the required amount of heat from the already heated one. The device transfers heat energy from the heating medium to sanitary water, as well as from the combustion gas directly to the heating medium.
Depending on the method of transferring heat to liquids, the following types of heat exchangers are distinguished:
- Primary – energy is transferred from gas to coolant;
- Secondary – energy is transferred from liquid to coolant;
- Bithermal, a feature of which is a double exchange of heat from the coolant to water and from gas to the coolant.
Differences between the types
The outer pipe is designed for circulation of the coolant in the heating system, while the inner pipe is for the movement of sanitary water. In the heating mode of operation, the combustible gases release heat, which is delivered directly to the coolant. If the heat exchanger operates in hot water supply mode, then the heat is first transferred to the coolant, after which it goes to the circuit.
Heat exchangers do not have a high-temperature heating element, the burnout of which is the most common cause of a water heater breakdown. The heat exchanger of an indirect heating boiler is overgrown with a scale much more slowly and this does not pose a particular danger to it.
However, it also has some drawbacks. For example, the transfer of heat energy in the FHP mode is somewhat limited. It leads to a decrease in the volume of prepared heated water when compared with other types of heat exchangers. Another limitation is that experts do not advise using this device in those regions where water is characterized by a high content of hard salts in its composition.