[TRNSYS-users] Type954

[Jeff Thornton]

<I have the following situation. I have an input data file with the
QCOOL from a server room which was served by a split unit. Now I am
trying to find the electrical consumption of the split unit, both indoor
and outdoor.
 I was hoping to modulate the indoor fan flow until the
delivered cooling to the room equals my QCOOL. I set parameter10 "Total
air flow rate" (the air flow over the indoor unit coil) to -1, so that I
can pass it the flow as described. I have an itterative controller that
watches the total cooling rate of the type, compares it to my QCOOL
data, and tries to set the input4 "Return air flow rate" (the flow rate
over the inside unit coil) so that the cooling powers match. Various
flow rates seem to have no effect. Any ideas?> 

That model uses the
user-provided flow rate and then "looks up" the performance of the heat
pump in the external data file given the temperatures, flow rate, etc.
Did you modify the external data file to provide performance at the
off-rated flow conditions such that you can back out the capacity at the
current flow rate? If you're using the default files, the flow rates are
set pretty close to the nominal flow rate - and the model does not
extrapolate beyond the data points - so you're not going to see a
difference in capacity as you slow the air flow down or speed it up past
the current minimum and maximum values in the data file. 

Jeff


---

Jeff Thornton 

_President - TESS LLC_ 

_22 N. Carroll Street,
Madison WI USA 53703_ 

_Office: (608) 274-2577 Fax: (608) 278-1475_


_www.tess-inc.com_ 

_E-Mail: thornton at tess-inc.com_ 

On 11/19/2012
2:31 am, Jean Marais wrote: 

> Dear Group,
> 
> Regards,
> Jean.
 
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