Interzonal Ventilation

[hs]

A question arise on how to input mechanical and inter zonal ventilation rates.
We need detailed information on how to specify the inter zone ventilation rates properly in Wufi Plus 2.5.x.
In the ventilation input panel, it is not available to specify explicit windward or leeward information on mechanical ventilation and interzonal ventilation rate. In order to assume the consistent ventilation rates occurring supply air volume and exhaust air volume in valance, please let us know how to input ventilation rates.

For the concrete discussion, let us assume two simple cases consisting of three zones as follows;
Note that Figs and Tabs are properly described in the attached Excel file.

[Case1]: Assume three serial connected zones such as;

Fig.1
+------+------+------+
| | | |
| Zone1 | Zone2 | Zone3 |
| | | |
+------+------+------+

and assume Mechanical Ventilation and Inter Zonal Ventilation as follows;

Tab.1
Windward Leeward Zones (Unit: cbm/h) Exhaust
Zone OA Zone 1 Zone 2 Zone 3 Rate
OA - 100 0 0 100
Zone 1 0 - 100 0 100
Zone 2 0 0 - 100 100
Zone 3 100 0 0 - 100
Supply Rate 100 100 100 100

Natural ventilation: assumes each zone has 0.01 ACH with OA,
We understand this value is specified by the natural ventilation occurred by infiltration and exfiltration.

[Case2]: three inter connected zones such as;

Fig.2
+------+------+
| |
| Zone1 |
| |
+------+------+
| | |
| Zone2 | Zone3 |
| | |
+------+------+

and assume Mechanical Ventilation and Inter Zonal Ventilation as follows;

Tab.2
Windward Leeward Zones (Unit: cbm/h) Exhaust
Zone OA Zone 1 Zone 2 Zone 3 Rate
OA - 200 50 0 250
Zone 1 100 - 50 50 200
Zone 2 50 0 - 50 100
Zone 3 100 0 0 - 100
Supply Rate 250 200 100 100

Natural ventilation: assumes each zone has 0.01 ACH with OA,

[mpazold]

You only have to define the supply volume flow rates, because you only need the air attributes of the incomming air to simulate the indoor climate.

It is assumed that the exhaust air is equal to the supply air. If the exhaust volume flow rate is more than the defined supply air you can either cancel the calculation with an error or increase the air supply from outer air (selectable in "other parameters" for each zone).

Following this, for case 1 you have:
- mechanical ventilation in Zone 1 = 100 m³/h
- interzone ventilation in Zone 2: From Zone 1 = 100 m³/h
- interzone ventilation in Zone 3: From Zone 2 = 100 m³/h

Of cause, with additional natural infiltraten 0,01 1/h and if you set the above mechanical and interzonal ventilation rates (supply = exhaust), 0,01 * Net volume additional infiltrates the zones per hour and leaves zone 1 and 2. In Zone 3 the leaving air volume flow is the natural: 0,01 * Net volume + the incomming interzone volume flow from zone 2: 100 m³/h.

Same concept for case 2:
- mechanical ventilation volume flows in Zone 1 = 200 m³/h and Zone 2 = 50 m³/h
- interzone ventilation in Zone 2: From Zone 1 = 50 m³/h
- interzone ventilation in Zone 3: From Zone 1 = 50 m³/h and From Zone 2 = 50 m³/h (you can switch the Zone in the dropdown menue. the values are stored for the defined zones).

Don't forget, if you set mechanical ventilation rates or volume flows for a zone, you also have to define a HVAC System for mechanical ventilation. (In Case 1 for zone 1; In Case 2 for Zone 1 and 2) with the capability.

[hs]

Thnk you for the reply and let me double check few more things.

| - interzone ventilation in Zone 3: From Zone 1 = 50 m³/h and From Zone 2 = 50 m³/h
| (you can switch the Zone in the dropdown menue. the values are stored for the defined zones).

1. However only one interzonal ventilation entry can be displayed in each zone,
the current plus version can handle multiple interzonal supplies from neighboring zones
as well as interzonal exhausts to neighboring zones. Is this correct?
How can we confirm these multiple interzonal supplies in the input or result section?

2. What is the difference between the natural ventilation and the mechanical ventilation except for that
the mechanical ventilation should accompany the counter entry on the device capability in the HVAC section?

Thank you in advance for your follow-ups.

[mpazold]

1. Yes, multiple interzonal air supplies from neighboring zones is possible, even it is not listed in the interzonal ventilation tab. However if you switch the zones in the dropdown, the designed values for the different zones are displayed.

You can check it after the simulation, maybee within the Airflow results graph for each Zone. You can add the Interzonal Ventilation curve for each zone. The interzonal supply air from all defined flow rates is shown.

2. the air exchange due to natural and mechanical ventilation is handled quite equal. Except the mechanical ventilation control, and a possible HRV/ERV or moisture recovery efficiency for the system.