RE: [EnergyPlus_Support] AFN cracks on partition sub-surfaces

If you have a double door which remains open all the time, it is not necessary to separate zone into two.

If you blow air into one room and exhaust it in the other, the total heat balance is still as one zone because the air is fully sturred.

The room air model will provide you with some temperature gradient information in the zone , but it does not change the heat balance situation.

If you have a leak from outdoor, then the condition is different. This would be an infiltration and still does not need the full AFN.

I think, AFN requires two windoes to be open at the same time, to the outdoor environment.

A partition is not connected to or in the outdoor environment (tank).

Dr. Li

To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: jeannieboef@xxxxxxxxx
Date: Tue, 8 Nov 2011 13:18:06 +0000
Subject: [EnergyPlus_Support] AFN cracks on partition sub-surfaces

Dear Group,
AFN is not intended to model large openings such as holes. What is the best setup for parameters for a hole when using AFN?

Currently I'm using this for a double door sized hole:

AirflowNetwork:MultiZone:Component:DetailedOpening,
118348_Partition_1_0_0_0_0_0_Hole, !- Name - Hole
0.1, !- Air Mass Flow Coefficient When Window or Door Is Closed (kg/s @ 1Pa per m crack)
1.0, !- Air Mass Flow Exponent When Window or Door Is Closed (dimensionless)
1, !- Type of large vertical opening (LVO)
0, !- Extra crack length for LVO type 1 with multiple openable parts (m)
2, !- Number of Opening Factor Values
0, !- Opening factor #1 (dimensionless)
1.00, !- Discharge coefficient for opening factor #1 (dimensionless)
0, !- Width factor for opening factor #1 (dimensionless)
1, !- Height factor for opening factor #1 (dimensionless)
0, !- Start height factor for opening factor #1 (dimensionless)
1, !- Opening factor #2 (dimensionless)
1.00, !- Discharge coefficient for Opening factor #2 (dimensionless)
1, !- Width factor for Opening factor #2 (dimensionless)
1, !- Height factor for Opening factor #2 (dimensionless)
0, !- Start height factor for Opening factor #2 (dimensionless)
0, !- Opening factor #3 (dimensionless)
0, !- Discharge coefficient for Opening factor #3 (dimensionless)
0, !- Width factor for Opening factor #3 (dimensionless)
0, !- Height factor for Opening factor #3 (dimensionless)
0, !- Start height factor for Opening factor #3 (dimensionless)
0, !- Opening factor #4 (dimensionless)
0, !- Discharge coefficient for Opening factor #4 (dimensionless)
0, !- Width factor for Opening factor #4 (dimensionless)
0, !- Height factor for Opening factor #4 (dimensionless)
0; !- Start height factor for Opening factor #4 (dimensionless)

AirflowNetwork:MultiZone:Surface,
118348_Partition_1_0_0_0_0_0_Hole, !- Name of Associated Heat Transfer Surface
118348_Partition_1_0_0_0_0_0_Hole, !- Leakage Component Name
118348_Partition_1_0_0_0_0_0_Hole, !- External Node Name
1, !- Crack Actual Value or Window Open Factor for Ventilation (dimensionless)
Constant, !- Ventilation control mode
, !- Ventilation temp schedule
, !- Limit on multiplier for modulating venting open factor
, !- Lower value on inside/outside temperature difference for modulating the venting open factor
, !- Upper value on inside/outside temperature difference for modulating the venting open factor
, !- Lower value on inside/outside enthalpy difference for modulating the venting open factor
, !- Upper value on inside/outside enthalpy difference for modulating the venting open factor
; !- Venting Availability Schedule Name

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