Details on Ventilation

If the Domestic ventilation module is activated, the settings between the two modules are automatically synchronized.

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Module overview ➤ Heat load ➤ Room level ➤ Ventilation

Ventilation system

Drop-down list for selecting the installed ventilation system.

When a ventilation system istinstalled for the room, the supply air volume flow must be heated. This can be done in the room or through an air heater. The heat output required for heating is included in the heating load and results from the temperature difference between the room temperature and the temperature after heat recovery (HR). The temperature difference between the supply air temperature and the temperature after the HR determines the heat output for the air heater.

If the Domestic ventilation module is activated, the settings for the ventilation system are synchronized between the two modules Domestic ventilation and Heat load and, if necessary, settings that have already been defined in the domestic ventilation are applied. If the Domestic ventilation module is not activated, the type of ventilation system is usually taken from the general heat load data. In such case, From ventilation zone setting is displayed in front of the name of the ventilation system. If the ventilation system in the room is to differ from the setting at ventilation zone level, select a different system here.

The choice of the system type is decisive, since the extract air temperature is determined as a mixed temperature from all extract air volume flows of the supply and extract air system, which is used for the calculation of the supply air temperature according to the HR. The following figures illustrate the choice of the air handling unit of a room depending on the unit constellation and the possible settings of the system types.

Supply air system
Extract air system
Supply and extract air system

Air change rate: Air change rate to be entered manually. The supply air and extract air volume flow are then calculated. If you change supply air or extract air volume flow, the air change rate is adjusted accordingly based on the larger volume flow rate.

Supply air flow rate: Quantity of air that flows into the room via the ventilation system. If you have also specified the extract air volume flow rate, the air change rate is calculated based on the larger volume flow rate. Clicking calculates the supply air volume flow rate with the standard air change rate 1.5 and the room volume. If you have activated the domestic ventilation module, manual values are reset to the values from the domestic ventilation by clicking on .

Extract air flow rate: Quantity of air that is discharged from the room via the ventilation system. If you have also specified the supply air volume flow rate, the air change rate is calculated based on the larger volume flow rate. Clicking calculates the extract air volume flow rate with the standard air change rate 1.5 and the room volume. If you have activated the domestic ventilation module, manual values are reset to the values from the domestic ventilation by clicking on .

Supply air temperature after HR: Displays the temperature of the supply air after heat recovery in supply and extract air systems with heat recovery. The Supply air temperature after HR is used for the calculation of ventilation heat loss of the heat load. The coverage of ventilation heat losses by an air heater in relation to the supply air flow rate and Supply air temperature is displayed in the Results tab.

Supply air temperature: The supply air temperature is suggested as follows, depending on the type of ventilation system:

In supply and extract air systems, the supply air temperature is determined according to standards with the heat recovery rate. For pure supply air systems, the outdoor temperature is taken from the general heat load data as supply air temperature.

The supply air temperature can also be freely entered, the value then appears in bold. Click inserts the determined value as described.

Hygienic minimum ventilation heat loss

The minimum ventilation heat loss results from the hygienically required minimum air volume flow, which is determined from the air change rate. Minimum air exchange rates for residential buildings are proposed based on the heating load standard. For non-residential buildings, the minimum volume flow/air exchange rate is proposed according to adequate standards depending on the selected room type. For more information for the calculation of individual room types, see “About the default values for the minimum air exchange in non-residential buildings". By clicking , you can reset manually entered values and use the standard values again. Alternatively to the air change rate, an area-related volume flow can be entered. The net room volume is automatically taken from the general room data.

Supply air volume flow by overflow

The volume flow rate Ve,u flowing in from outside is not relevant for the consideration in this standard and therefore deactivated.

Volume flow rate Vb: Volume flow rate which flows in from one or more adjacent rooms must be entered manually or is taken from the ventilation concept if the domestic ventilation module is activated. The proposed volume flow rate is the difference between the exhaust and supply air, if the difference is greater than 0. With a manual input the value can be overwritten, clicking resets the value.

Supply air temperature Vb: The average temperature of the air flowing in from adjoining rooms must be entered manually.

Volume flow rate Viso: Volume flow rate that flows out of the room. This value is not included in the calculation of ventilation heat losses. The volume flow rate is calculated from the difference between supply and extract air, if the difference is greater than 0.

Supply air temperature Viso: Average temperature of the air flowing out of the room. The value corresponds to the standard inside temperature of the room.

Further volume flow rates

Volume flow rates entered here are included in the calculation of the ventilation heat losses.

By combustion or technically required: Volume flow rate discharged from a heated room, which in the case of a ventilation system was not included in the extract air volume flow of the ventilation system - typically with combustion air.

Through outside air diffusers: Design air volume flow rate of the outside air diffusers in the room. This value is taken from the ventilation concept, as long as the domestic ventilation module is activated.

Through large openings: Additional volume flows through large openings like gates.

Information on domestic ventilation

Opens the Domestic ventilation DIN 1946-6 dialogue, in which the calculated volume flows of the ventilation concept are displayed.