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



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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