[TRNSYS-users] Type 4
kummert at engr.wisc.edu
Mon Oct 25 12:40:05 PDT 2004
> reading the general description in the manual, I find for Type 4 to set
> the parameter 6 on a negative number which is in absolute value equal to
> the height of the thank.This would result in equal size nodes in the
> stratified storage tank.
> Doing this seems impossible as parameter 6 needs to be greater than 0.
> It would have been a nice tool, if it worked. Did someone encounter the
> same problem and was there someone who solved it in an elegant way?
Type 4 and Type 60 provide a level of flexibility (and a complexity)
that is beyond what IISiBat proformas can take, unless you think that 30
proformas for those two types is not enough...
If you want to use the mode you mention, a workaround is to define 2
HTank = 1.5 ! the real height of your tank
HNode = HTank/5 ! Assuming you need 5 nodes
And then use a proforma such as Type4c (for variable inlets, uniform
losses) where you declare 5 nodes and enter "HNode" for the height of
each node (after changing the variable type to String).
This can be adapted to any number of nodes. Changing the tank height
will then be as easy as changing the first equation. Of course, you will
need to adapt the projects if you change the number of nodes but you
would have to do that anyway (change the number of derivatives and
outputs in Type 4, etc.).
Another option is to create your own proforma for the particular mode
you want to use.
PS on a side note, changing the height of a tank in a simulation without
changing the number of nodes and the position of inlets, auxiliary
heaters etc. will not change the results very much (besides the
increased/decreased volume) since the model's assumption is that one
node is one volume of fluid at a given temperature, no matter what its
physical height is.
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