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Details on Ventilation

Information on the Ventilation section in the Heat load tab of the room level.

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

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Module overviewHeat loadRoom levelVentilation

Ventilation system

Drop-down list for selecting the installed ventilation system.

If there is a ventilation system in the room, the supply air volume flow rate must always be heated when the supply air temperature is below the room temperature.

If the ventilation system is used to cover the heat load (or part of it) of the room, this proportion must not be taken into account in the heat load calculation for the room. In this case the supply air temperature will be adjusted to the actual value.

The type of ventilation system is usually taken from the general heat load data. In this case, From project setting is displayed in front of the name of the ventilation system. If the ventilation system in the room should deviate from the project setting, select a different system. Depending on the ventilation system selected, fields that do not apply are deactivated.

Air change rate: Enter the air change rate. 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 selected system B or system D as the ventilation system, the minimum volume flow is entered here.

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 selected system C as the ventilation system, the minimum volume flow rate is entered here and divided 50% each between the air volume flow q_V,e coming from outside and the air volume flow q_V,ji coming from other rooms.

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

In supply and exhaust air systems, the supply air temperature is determined 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. If you click the supply air temperature is determined as described.

Minimum volume flow rate

The minimum volume flow rate is calculated according to the specifications of the building regulations.

Spec. Air volume flow rate: The specific volume flow rate is entered based on the building regulations and depends on the selected room type. The value can be adjusted manually. Click to reset the value to the one specified in the building regulations.

Air change rate: The air change rate is the quotient of minimum volume flow rate and internal room volume. The air change rate is only displayed here.

Volume flow rate: The minimum volume flow rate is calculated from the product of the specific volume flow rate and the room area.

Amount of individuals: This input is only active for calculations according to ISSO 53. When a room type is selected, the number of persons per area is calculated here, if available, according to the building regulations from the reference value for the number of persons per area. The number of persons can also be entered manually. The number of persons influences the minimum air volume flow rate.

Room area: The room area is automatically adopted from the general room data and displayed here.

Supply air volume flow rate by overflow or infiltration

Volume flow rate q_i: The calculated infiltration volume flow is entered here. This volume flow is not part of the air balance.

Supply air temperature q_i: The temperature of the infiltration volume flow rate. This temperature corresponds to the outside temperature.

Volume flow rate q_V,e: The air flowing in from outside to ensure the minimum air change rate. If you have selected system A as the ventilation system, the minimum volume flow is entered here. If you have selected system C as the ventilation system, 50% of the minimum volume flow is entered here. The value can be adjusted manually. Click on resets the value.

Supply air temperature q_V,e: The temperature of the air coming in from outside. This temperature corresponds to the outside temperature.

Volume flow rate q_v,ji: Volume flow rate which flows from the inside of one or more adjacent rooms must be entered manually. The proposed volume flow rate is the difference between the exhaust and supply air, if the difference is greater than 0. If you have selected system C as the ventilation system, 50% of the minimum volume flow is entered here. With a manual input the value can be overwritten, clicking resets the value.

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

Volume flow rate q_V,ij: 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 q_V,ij: Average temperature of the air flowing out of the room. The value corresponds to the standard inside temperature of the room.