Double-circuit boiler (definition)

Double-circuit boiler - this is a type of heating boiler, which is designed to simultaneously perform two functions: heating the room and providing hot water supply (DHW). A double-circuit boiler has two separate circuits:

1. Primary circuit: Designed to circulate the coolant in the heating system, providing heat to radiators or other heating devices.
2. Secondary circuit: Used to heat water for domestic use such as hot water in taps and showers.

A double-circuit boiler using pellet technology is not manufactured

Pellet boilers are usually designed to operate exclusively in heating mode, a double-circuit boiler in this case is not effective from an engineering point of view. Preparation of hot water for domestic use (DHW) in such systems is most often taken outside the boiler circuit and is carried out by separate devices, such as indirect heating boilers connected to the boiler. The main reasons are:

1. Technical complexity: Pellet boilers have a complex combustion and pellet supply control system. The introduction of a second circuit for DHW adds complexity to control and reduces the efficiency of the system.
2. Features of combustion: Pellet boilers are designed for long-term and stable operation in heating mode, while hot water production requires periodic operation of the boiler at peak power. This can cause inconvenience and reduce the overall efficiency of the boiler.
3. Solution via external boiler: In pellet boiler systems, hot water for domestic hot water supply is usually prepared using external indirect heating boilers. These boilers receive heat from the main boiler via a heat exchanger, which provides more flexible and reliable control of the water heating process.

Thus, double-circuit heating systems based on pellet boilers have not become widespread, since it is better and more efficient to solve the problem of hot water supply through external modules and with the help of hydraulic piping, providing a rich solution space.