Solar tubing - Balanced or Unbalanced headers?

[tomfrh]

I’m about to replace my rooftop solar tubing with new material. A lot of suppliers show the balanced Z-manifold design, where the return header does a U-turn.

Other vendors use the unbalanced approach, with a U-manifold design, which is simpler.

My instinct is that an unbalanced approach would be ok and the tubes will balance the flow close enough regardless, due to most of the resistance coming from the tubes themselves, and not the header pipes. I could be entirely wrong about that of course..

Thoughts?

 

[Texas Splash]

Let's see if @mas985 can give you some assistance on this one.

 

[mas985]

Z, supply and return at opposite ends of the panel, is always more efficient. The larger the panel, the bigger the difference. Also, the smaller the header, the bigger the difference. Theoretically, if the headers had a very large diameter, >3", it might not matter. But for 1 1/2" or 2", I would always use a Z design.

How many panels and what size are they?