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PostPosted: Thu Jul 02, 2020 7:35 am 

Joined: Thu Jul 02, 2020 7:05 am
Posts: 1
1. we are using bifacial solar module in one of our project.
2. The module temperature ( of bifacial module) is being measured by CS240 temperaure sensor( make-compbell scientic) . This temperature sensor is fixed at back side of solar module.
3. The module temperature ( of bifacial module) is also calucated by NREL method/ sandia module temperature model.

We are finding large difference between these two values
Difference= MOD_TEMP (Measured by CS240) - NREL_MOD_TEMP (Calculated-NREL method)
this difference is i the range of -9% to 36% based on irradiance during the day.

Request you to support to resolve below query
1. Why there is difference?
2. is suitable to measure module temperature of bifacial solar module ( since it is fixed at only one side).
3. What is suitable module temperature sensor to measure module temp of bifacial solar module so that the measured & calculated temperature(NREL) values should match.

Regards,
Vilas Pacharne
vilasgpacharne@gmail.com


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PostPosted: Sat Aug 08, 2020 8:03 pm 
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Joined: Mon Apr 16, 2012 7:29 pm
Posts: 1686
The measurement of modules temperature in a field is a delicate operation.
To my mind, just gluing the sensor on the backside of the module is not quite correct. The layout of the measurement is very important. Remember that a temperature sensor always measures its own temperature !
See our FAQ "How is evaluated the Module temperature during the simulation ? ".
At the end of this post you have a paragraph with our advices: "PV array temperature measurement"

Now PVsyst doesn't use the Sandia or NREL thermal model.
It proposes a model in which you can adjust the "Thermal Loss factor" (U-value) in order to match you measurements at best.
Please read the help "Project design > Array and system losses > Array Thermal losses".

NB: expressing temperature differences in terms of percentages doesn't make sense. Percentage with respect to what ?
If it is 0°C, this doesn't have a physical meaning. The reference could be anything else (25°C, -273°C, etc)
The only way is to express the temperature differences in terms of °C.


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PostPosted: Tue Jan 19, 2021 9:18 am 

Joined: Tue Jan 19, 2021 9:16 am
Posts: 2
Quote:
1. we are using bifacial solar module in one of our project.
2. The module temperature ( of bifacial module) is being measured by CS240 temperaure sensor( make-compbell scientic) . This temperature sensor is fixed at back side of solar module.
3. The module temperature ( of bifacial module) is also calucated by NREL method/ sandia module temperature model.

We are finding large difference between these two values mcdvoice
Difference= MOD_TEMP (Measured by CS240) - NREL_MOD_TEMP (Calculated-NREL method)
this difference is i the range of -9% to 36% based on irradiance during the day.

Request you to support to resolve below query
1. Why there is difference?
2. is suitable to measure module temperature of bifacial solar module ( since it is fixed at only one side).
3. What is suitable module temperature sensor to measure module temp of bifacial solar module so that the measured & calculated temperature(NREL) values should match.
Your blog is simply amazing, congratulations on your great work!


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PostPosted: Tue May 25, 2021 7:53 am 

Joined: Tue May 25, 2021 7:52 am
Posts: 1
.


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