[TRNSYS-users] TRNFLOW - Pressure drop through fan

[Arnaud Candaele <arnaudcandaele@gmail.com>]

Hi everyone,

I have a little problem with a pressure drop through a fan. I have an Auxiliary node at 0 Pa, linked to a thermal node.
The link is defined FROM Auxiliary node TO thermal node.

When I observe the pressure drop through the fan, I get a positive pressure drop through the fan, which means according to the documentation that my auxiliary pressure is ABOVE my thermal node pressure... When I monitor also my thermal node pressure, I indeed get a negative pressure corresponding exactly to that pressure drop.

But if I also observe the flow into my thermal zone, and through the fan, I get positive flows INTO my thermal zone.

I don't understand, because also from documentation, the fan curve links pressure drops as (pressure in "TO node" - pressure in "FROM node") for a flow that is defined positive in the direction FROM to TO.

Thus, how can I get both a positive flow from my "FROM" node (auxiliary) to my "TO" node (the thermal node) AND in the same time have a higher pressure in my auxiliary node... ?

What am I missing here?

Of course what I want is to raise the pressure through this fan thus have a higher pressure in my thermal node than in my auxiliary node.

Thanks for your help !

Arnaud.