[TRNSYS-users] Low temperatures using evacuated tube solar collector (type 71)

[David BRADLEY via TRNSYS-users]

Ahmad,

   There isn't really enough information in the screen captures that you 
sent in order to check and see if there are connection or parameter 
errors in the simulation. I would suggest that you look at the qUseful 
output from Type71 and compare it (on a per unit area basis) to the 
incident solar radiation when there is liquid flowing through the 
collector. From this you can get an instantaneous collector efficiency. 
Better yet you can integrate qUseful and qIncident and compare those to 
get a longer term average collector efficiency. The efficiency rather 
than the collector outlet temperature will give you a better idea of 
whether there are errors in the way that the simulation is set up.

kind regards,

  David



On 06/02/2017 10:15, ahmad abbasian via TRNSYS-users wrote:
>
> Hello
>
> I'm simulating a solar assisted heating system. I have used type 71 
> (evacuated tube collector) for my model. The tested flow ate is 
> 0.014kgr/S.m2 and the area is 2m2 so the flow rate is set to 0.028 
> kgr/S. The other parameters are based on the two attached tables. I'm 
> wondering that the outlet water temperature is low which seems to be 
> unacceptable. I think that the water outlet temperature can be reach 
> to around 100 C in such collector, but the maximum temperature here is 
> 40 C ! following is the inlet and outlet temperatures to collector. 
> pump is controlled using a differential controller to be turned on 
> whenever the outlet temperature is 5 C more than the inlet 
> temperature. What is wrong with my simulation?
>
>
>
>
>
> ..............................................................................................
> Ahmad abbasianzadeh
> Solar energy Researcher
> *Harrisburg, Pensylvania*
>
>
>
>
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-- 
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David BRADLEY
Principal
Thermal Energy Systems Specialists, LLC
22 North Carroll Street - suite 370
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d.bradley at tess-inc.com

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