[TRNSYS-users] Type 56 active layer

[David Bradley]

Stefan,

> 1. How is the number of loops respectively the pipelength according to
>   the equation in the manual part 6 defined?
>
> Here is an example:
> Floor Area: 80 m2
> Pipe spacing: 0.15 m
>
> What is the number of loop in this example if I have an single input
>   an an single output?
>    
the active layer model assumes that you always have a single inlet and a 
single outlet to a given floor. There are then assumed to be a number of 
loops all connected to the same manifold. The number of loops should be 
used to limit the length of pipe in a given loop. If you truly want to 
have a single pipe running all through the floor then you would specify 
one loop. If you specify two loops, there will be assumed to be a 
manifold where the inlet flow splits to two parallel pipes each of which 
is half as long as the single pipe was.
> 2. I tried to use the active layer for heating. I simulated a heat
>   source which outputs are connected to the input of the active layer.
> After switching it off I see a sudden fall of temperature at the
>   outlet of the active layer insteand of an expected exponential
>   decrease (see picture).
> Does anybody why this happens? What is the cause? How to fix it?
>    
I suppose that if there is poor energy transfer between your piping loop 
and the floor layer that contains the piping loop then you might see the 
kind of behavior in that plot. Keep in mind that you are plotting the 
outlet fluid temperature, not the temperature of the floor layer. The 
floor layer may stay warm even though the temperature of fluid coming 
out of it drops. This might be especially true if you turn off the heat 
source but leave the floor liquid flow rate going all the time.
Best,
  David
-- 

***************************
David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
Madison, WI  53703 USA

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