Temperatures and volumetric flow rate

Temperature difference

From an energy perspective, it makes the most sense to achieve the highest possible temperature difference, as this reduces the mass flow rate for the same heat output. This minimises pressure losses in the pipework of existing systems, thereby reducing the electrical energy consumption of the circulation pumps. With new systems, the dimensions of the pipework and pumps may be smaller. This applies to both the heat consumer circuits and the heat generator circuits.

On the consumer side, the temperature difference is determined by the respective application. A sensible design is based on temperature differences of 20 K to 40 K. Temperature differences below 20 K should be avoided for energy reasons.

For the design on the boiler, a temperature difference of up to 40 K is appropriate. The maximum permissible temperature difference between the flow and return at the boiler is 40 K to 50 K, depending on the construction. Even greater temperature differences may lead to internal stresses on the boiler and therefore to a reduction in service life or even damage to the boiler.

The minimum temperature difference in the design should not be less than 20 K in order to avoid unnecessarily large and cost-intensive pipe cross-sections for boiler flow and return as well as subsequent pipework and fittings, as the defined speed of 2.3 m/s should not be exceeded in order to prevent damage to the boiler sensors.

If consumers enable a higher temperature difference than is permitted for the boiler, the temperature difference for the boiler must be limited by boosting the return flow temperature or maintaining a high return temperature. Both functions are included, for example, in the module for the return flow temperature safeguard RTS.

Product: Return flow temperature safeguard RTS