Variant Menu: System Definition > External Heat Exchanger or System Schematic

Input dialog for the external heat exchanger

In this dialog, you can define the quality of heat exchange in the external heat exchanger. You have two options:

1. kA value:

   • Enter a specific kA value for heat exchange.
   • The kA value is used directly for simulation without conversion.
   • The logarithmic temperature difference is displayed but doesn’t affect the simulation.

2. Mean Logarithmic Temperature Difference:

   • Enter a specific value for the mean logarithmic temperature difference.
   • The kA value is then calculated based on this input.
   • A suitable value for maximum output is calculated from the system parameters.

For external heat exchangers used with a collector array connection, the value is typically calculated from a 500 W/m² collector surface area.

For external heat exchangers used to connect the buffer tank discharge to the DHW supply, Pmax is calculated based on the pump flow rates and the maximum possible temperature difference.

For heat exchangers used for auxiliary heating of a swimming pool, Pmax is calculated based on the power required to heat the pool from the cold water temperature to the target swimming pool temperature within 12 hours.

Configure the heat exchanger settings as needed for your system.

For more details, please refer to the complete documentation.