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Dear users,
Just recently a question came up regarding the outputs of Type 56 and TRNFlow, that we would like to share here for clarification:
Question:
I would like to ask a question about output variables when TRNFlow is enabled. When TRNFlow is used, Type56 reports the following outputs:
- QVENT
- QINF
Could you please briefly explain:
- the concept used to define QVENT and QINF when TRNFlow is enabled, and
- which airflow rates are used as the basis for the calculation and classification of QVENT and QINF.
Answer:
TRNFlow has three categories of "input mass flow rates" of airnodes (see TRNFlow manual Section 3.7. TRNFLOW Outputs; similar to Type 56 itself):
NTYPE 201: FLINZ Outdoor air infiltration flow per airnode [kg/h] from an external node (outdoor) into airnode:
- is used to calculate NTYPE 4: QINF = air mass flow * cp_air * (Tamb - Tairnode))
NTYPE 203: FLVSZ Ventilation supply flow per airnode [kg/h] Sum of all flows from auxiliary nodes into airnode
- the disaggreated mass flow rate of NTYPE 203 and the related temperature differences are used to calculate NTYPE 5: QVENT
NTYPE 205: FLIZZ flow into thermal airnode from specified thermal airnode [kg/h] Sum of all flows from another specified airnode into the thermal airnode
- inflow into a thermal airnode from a specified thermal airnode (coupling)
Question:
FLINZ, FLVSZ, and FLIZZ are not mapped directly to the Link type itself (e.g., Crack/Fan/Duct), but are determined by the types of nodes connected, i.e., where the flow comes from and where it goes.
Therefore, if a fan is connected directly from an external node to an airnode, the flow should be counted as FLINZ and thus contribute to QINF, not FLVSZ/QVENT.
On the other hand, if outdoor air is first taken into an auxiliary node (duct system) and then supplied to an airnode, it is counted as FLVSZ, and the outdoor air fraction of that supply is also reflected in FLTOZ.
Correct?
Answer:
Yes, that is correct.
