Details on Ventilation
Information on the Ventilation section of the Heat Load module at room level.
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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 Ventilation module is activated, the settings for the ventilation system are synchronized between the Ventilation and Heat Load modules and any settings already defined in the Ventilation module are applied. If the 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 Systems |  |
| 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 the Ventilation module is activated, the volume flows between the two modules Ventilation and Heat Load are synchronized and any volume flows already defined in the Ventilation module are applied. 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 on 
opens a context menu in which you can reset the volume flow rate to the calculated value. If the Ventilation module is not activated when Reset to Calculated Value is selected, the volume flow rate is calculated using the standard air change rate of 1.5 and the room volume. If the Ventilation module is activated, any deviating values are reset to the values defined in the Ventilation module.
Extract air flow rate: Quantity of air that is discharged from the room via the ventilation system. If the Ventilation module is activated, the volume flows between the two modules Ventilation and Heat Load are synchronized and any volume flows already defined in the Ventilation module are applied. 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 on opens a context menu in which you can reset the volume flow rate to the calculated value. If the Ventilation module is not activated when Reset to Calculated Value is selected, the volume flow rate is calculated using the standard air change rate of 1.5 and the room volume. If the Ventilation module is activated, any deviating values are reset to the values defined in the Ventilation module.
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 the ventilation heat losses by an air heater in connection with the Supply Air Volume Flow Rate and the Supply Air Temperature is displayed on the Results.
Supply air temperature: The supply air temperature is suggested as follows, depending on the type of ventilation system:
For supply and extract air systems, the supply air temperature is determined for each ventilation zone depending on the standard with the degree of heat recovery or taking into account air heating. 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. Clicking on to open a context menu in which you can choose between the options Reset to value from CAD and Reset to calculated value. Click on Reset to value from CAD to enter the value that was determined when the building was entered from CAD. Click on Reset to Calculated Value to enter the data determined according to the standard. If the Ventilation module is activated, the volume flows determined there can influence the supply air temperature.
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. Further information for the calculation of the individual room types can be found on the page “About the default values for the minimum air exchange in non-residential buildings”. You can manually reset individual values. Clicking on to open a context menu in which you can choose between the options Reset to value from CAD and Reset to calculated value. Click on Reset to value from CAD to enter the value that was determined when the building was entered from CAD. Click on Reset to Calculated Value to enter the volume flow rate determined according to the standard. 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
Volume Flow Rate Vb: Volume flows from one or more neighboring rooms must be entered manually or are taken from the ventilation concept if the 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 if the Ventilation module is activated.
Through Large Openings: Additional volume flows through large openings like gates.