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Safety valve

Valve for draining pressure in water tank of heat generator if pressure exceeds the maximum permissible operating pressure


Seal at pipe joints

Seal ring

Seal at pipe joints

Sealing collar

Seal at pipe joints

Secondary pump

Transports the energy source from heat exchanger to consumer

Self-reliant heating device

Heating device that has its own heat source and for this reasons does not need to be connected to a heat source.

Sensible heat

Perceptible heat Thermal energy that can be measured by temperature change.

Sensor temperature

Temperature measured by the sensor

Source temperatures

Heat source temperature used by the heat generator.

Specific heat demand

Net heating demand with regard to space to be heated or area to be heated


Rotation frequency

Speed controlled

When the performance of a device is controlled by speed, it is referred to as speed-controlled device

Standby loss

The standby mode of a heat generator or storage tank requires a certain amount of energy to be maintained at the respective temperature. This energy is called standby loss

Suction well

Used for intake of groundwater to the heat pump to extract thermal energy from it.

Surface losses

Loss of heat of energy generator to the environment that is not available as useful thermal heat.

System curve

Includes static energy level and dynamic friction losses due to fittings and shaped parts

System expenditure

Parameter for primary energy demand of a building in accordance with DIN V 4701-10

System expenditure ep

Ratio between primary energy input of a heating system and the useful heat output in accordance with DIN V 4701-10