About single-pipe systems

Explains the concept of single-pipe systems for radiators and cooling convectors.

Dimensioning of radiators and cooling convectors with single-pipe connection can be done at room level, apartment level, storey level or at project level.

In single-pipe systems, the mass flow rate of the pipe run is divided. The target value for mass flow rate partition determines what percentage of the mass flow rate is directed to the consumers. The rest of the mass flow rate is bypassed past the consumer and mixed again with the consumer's return flow. In the case of heating systems, this results in a steadily decreasing supply water temperature within the series connection from the first to the last radiator. For this reason, planning measures are necessary, such as the use of larger radiators at the end of the series connection, so that the required heat can be transferred. Therefore, the order of the consumers within the series connection of a line (ring line) is decisive. Radiators in rooms with large heat demand should be placed at the beginning of the single-pipe run. The target value for mass flow rate partition is adopted for all new pipe runs, but can be adjusted in the individual single-pipe runs.

The distribution of the mass flow rate is controlled by one-pipe radiator valve, which are used instead of radiator lock shield valves on each consumer. The hydraulic balancing then takes place only via regulating valves and no thermostatic valves are needed.

When placing and piping the consumers in the CAD program, the sequence within the series connection must be followed exactly. During the calculation, it is determined whether the supply water temperature of the radiators or cooling convectors within the series connection decreases or increases accordingly. In this way, it is determined whether the consumers have been connected in the correct order. If this is not the case, a corresponding report is issued.