The distribution network ensures the transport of heat and / or cold between the generator and the emissive device, and between the generator and the air handling unit.

For optimization of heating curves, we refer to the following standards and methods:


ISSO Publicatie 32 (2011) bijlage D

(Building simulation) Principles of temperature simulation calculations, physical material data



It is possible to visualise the distribution using a particular colour. This colour will be used in the 3D visualisation in the results section. In case you assign conspicuous colours to the various templates, this will give you a quick overview of the different templates used in the project.



  • Gebouwsimulatie
  • Warmteverlies
  • EPG

This indicates what is provided by the distribution system: Hot, Cold, or Hot & Cold. In Hot & Cold, both hot and cold water are transferred to the same emissive device (change-over) depending on the need. A distribution network is also required for a heating or cooling coil of an air handling unit, however, for this a combined Hot & Cold network cannot be specified and two separate networks (one for hot, and the other for cold) should be specified.

  • Hot-water net distribution network for heating
  • Cold-water net distribution network for cooling
  • Hot- and cold-water net distribution network for both heating and cooling (change-over)
The choice of the system affects the selection of the distribution in the air handling unit and emissive devices. Example: a hot water network cannot be linked to a cooling coil or to an emissive device for cooling and vice versa.


  • Gebouwsimulatie
  • Warmteverlies
  • EPG

The generation configuration is chose here from the generators for heat and/or cold. Only generation configurations can be selected with generators for Hot, Cold, or Hot and Cold, depending on the specified system (Hot, Cold, or Hot and Cold respectively). The selection list is created automatically from all generation resources as specified under the resource Generation.

Other agent than water (e.g. coolant)

  • EPG

Checking this box indicates another cooling agent is used other than water, such as a coolant in multi-split systems. A correction will be made to the distribution efficiency for heating and/or cooling.

Accumulator present outside heated space

  • EPG

An accumulator for the heating system may be located outside the heated space in housing. If this is the case it can be indicated here and a correction on the distribution efficiency follows. This option has no effect in case of non-residential buildings.

Control mode

  • Gebouwsimulatie
  • Warmteverlies

Per room
In this control mode the temperature in all rooms can be guaranteed. An example of a control mode per room is a control with thermostatic valves in all rooms (not in combination with a room thermostat), for which the supply temperature is constant or being controlled by means of a heat curve.

The reheat surcharge for control per room is determined based on the accumulated surfaces in the room (see Reheat surcharge).

Room thermostat
In this control mode the temperature cannot be guaranteed in rooms other than the location of the thermostat. The room of reference in which the thermostat is located is defined before the installation concept can be linked to the given distribution network. Subsequently the system is activated or deactivated based on the difference in temperature between the specified design temperature and the actual air temperature in the room of reference. The room of reference of the thermostat can be set after the geometry definition and the specification of the various rooms, as specified in Temperature control rooms.

The reheat surcharge for a given room is determined as a percentage of the transmission and ventilation in case of room thermostat control. The reheat surcharge in other rooms is based on this same percentage as well. The reheat surcharge is determined for each room seperately if the room has not reheat surcharge.

Adaptive, or adaptive control, is a self-learning system which adapts to the results of the previous day(s). The burner should switch on and off frequently to maintain a constant room temperature. In non-adaptive control, the switching cycle is set by the installer. This is done by setting the anticipation elements in mechanical thermostats, and by choosing the right set points in digital control. In case of an adaptive thermostat, the switching cycle is set by the installer as well; however, these settings are adjusted by the control. The control results will improve after a few days. (Source: CV Tuning)

No reheat surcharge is applied in adaptive control. If zones have been specified, the operating mode ‘Night set-back’ and the control ‘per room’ are applied.


ISSO Publicatie 51 (2017) paragraaf 4.8

Surcharge for operational limitation

ISSO Publicatie 51 (2012) paragraaf 4.4

Chargeable surcharge for operational limitation Φo



The heating curves are important for optimization and energy reduction in distribution networks.

Temperature level

  • Gebouwsimulatie
  • EPG

The division into HT- and LT- systems can be specified here depending on the heat generation and distribution. The generation efficiency and distribution efficiency in the EPG calculation are based on this temperature level.

  • LT (Low Temperature): low temperature system. For EPG calculations, please consult NEN 7120, Tables 14.12 and 17.2.
  • HT (High Temperature): high temperature system.
Choosing the temperature level LT / HT has an effect on the selection of the emissive devices. This means you can only link an LT distribution network to an LT emissive device and vice versa.

NEN 7120, paragraaf

Calculation values for internal distribution efficiency

NEN 7120, paragraaf 14.6.4

Calculation values for generation efficiency

NEN 7120, paragraaf 17.9

Latent cooling demand (dehumidification)



  • Gebouwsimulatie

This selection indicates the determination of the heating curve. Three possibilities are available:

  • Default: the heating curve is determined using a default value, irrespective of daytime operation or night time operation, and irrespective of the outside temperature. The default temperature is 80 °C for heating, 35 °C for LT heating, 6 °C for cooling, 17 °C for HT cooling, and 18 °C for heating and cooling together;
  • User defined: the heating curve has constant values as specified for daytime operation and night time operation;
  • Heating curve: the heating curve is specified manually. For all values of outside temperature (Toutside) a value of the heating- or cooling water (Twater) can be specified. Separate curves can be defined for daytime operation and night time operation.

ISSO Publicatie 32 (2011) paragraaf 5.2

Temperatures of installations


Circulation system

Additional circulation pumps present

Additional pumps may have been installed for the heating system. In this case, which can be indicated here, extra electric auxiliary energy is charged. By default, the auxiliary energy is charged for the main circulation pumps only.


NEN 7120, paragraaf 14.7.2

Electrical auxiliary energy for heating (formules 14.31 & 14.33)


Pump(s) with (switch or) speed control

  • EPG

In this box it can be indicated whether the main circulation pumps (and additional circulation pumps if present) are equipped with a switch and/or speed control. If this is not the case, the runtime of the pumps increases which leads to more electric auxiliary energy to be charged.


NEN 7120, paragraaf

Calculation rules and values for pump power and operating time


Pipe specifications of the circulation system

Pipes are insulated in unheated spaces and/or crawl spaces

  • EPG

In this box it can be indicated whether the pipes in unheated spaces and/or crawl spaces in houses are insulated. This parameter affects the correction of the internal distribution efficiency. It also affects the distribution efficiency in non-residential buildings, which indicates whether the pipes in the system have been insulated.


NEN 7120, paragraaf 14.3.3

Internal distribution efficiency


Location of pipes

  • EPG

The structure of the distribution network for housing is specified here. This pipe structure contributes to the determination of the distribution efficiency.

  • Pipes along the facade
  • Insulated distributor
  • Uninsulated distributor

NEN 7120, paragraaf

Calculation values for internal distribution efficiency


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