PVT Collector Pressure Drop

The forum for all questions and discussions about Polysun Simulation Software (Designer / Standard)
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Posts: 1
Joined: Tue Nov 07, 2017 8:30 pm

Sat Feb 03, 2018 1:37 pm

Greetings. I have been trying to import a new PVT collector in Polysun for a project, but I'm having some difficulty adjusting the parameters related to pressure drop through the collector. Specifically, I am trying to adjust the parameters of the collector template I'm using so that the pressure drop/water flow curve I get is close to the one obtained through measurements. I am checking with an existing collector (the "Wave 280M non-isolated" template from DualSun) which (as stated here: https://dualsun.fr/wp-content/uploads/D ... asheet.pdf) has a dp of 4000 Pa at 200l/h, that is 40 mbar at 3.33 l/min. By checking with one such collector and using the template I've attached below, I get a pressure drop curve that seems to be about 20 times off. Maybe the issue is that I am reading the circuit pressure drop results from the pump, since I haven't found any other way to obtain pressure readings at the inlet and outlet of the collector. Are there any clues as to what I might be calculating wrong, or how I could get a more accurate result on the pressure drop? Thanks a lot!
Dualsun pressure drop curve.png
Dualsun pressure drop curve.png (13.73 KiB) Viewed 17475 times
pressure drop test.PNG
pressure drop test.PNG (12.13 KiB) Viewed 17480 times

Lars Kunath
Posts: 91
Joined: Thu Mar 02, 2017 2:35 pm

Tue Feb 06, 2018 9:47 pm

Dear kboutsi,

to calculate the pressure drop over the collector loop you need to be very careful. In the collector database there are values such as internal pipe diameter, length ... These values are most likely incorrect since they are not on the data sheets of the collector. If you try to change this values to realistic ones your curve will fit. Also please be aware that the fluid in the loop will have an influence (water?).
The pressure drop at the pump is the right value you need to look at.

best regards,


Posts: 1
Joined: Mon Feb 19, 2018 3:04 pm

Thu Mar 15, 2018 1:44 pm

Dear Kboutsi,

Be aware that we have different PVT products. You mentionned the Datasheet of the Spring (insulated version, exists also without insulation) and you used in Polysun the Wave (not insulated) which has a different heat exchanger and higher pressure drop.

To connect the modules, for the Wave it's a maximum of 6 in series (then pressure drop is 6000 Pa at 200 L/h for one module, so around 36 000 Pa for 6 modules)
For the Spring (newest and most efficient version), you can connect the modules in parallel and achieve lower pressure drop. For one module it's 4000 Pa at 200 L/h (for 6 modules : 4000 + 0,1x6x4000 = 6400 Pa)
For the flow, the target is 20L/h/m2
The Spring (insulated and not insulated versions are available in Polysun too).

Gabriel for DualSun

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