Go Back   EcoModder Forum > EcoModding > Aerodynamics
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 01-12-2021, 09:04 PM   #1 (permalink)
EcoModding Lurker
 
Join Date: Jan 2021
Location: Belgium
Posts: 5
Thanks: 2
Thanked 1 Time in 1 Post
Lightbulb Reducing the Drag of Rigid Solar Panels Mounted on a Van

Hello,
First post here !
I've designed an airfoil profile to help reduce the drag of rigid solar panels mounted on top of campers / vans etc.
Sorry I cannot post links as I'm new

I already shared the designs here:
http://sprinter-source.com/forums/in...threads/93869/

and also on thingiverse:
Front: http://thingiverse.com/thing:4708973
Rear: http://thingiverse.com/thing:4719660

Those profiles can be printed with 3D printer and cut and assembled at the desired length.
Those profiles are straightforward and mimic a drop/airfoil profile.

I'm posting here because there is a more difficult problem:

rigid solar panels are preferred because they are more durable and more powerful by size.
They allow heat to escape under the panel and this geatly enhance the power output, a hot panel produces way less than a colder one.

So ..
With my profiles, I "solve" the front and rear drag, but there are two more edges, "inside" the panel:

Sorry I cannot post images or links, hope you will understand.

And if there was no problem with the cooling, I think the shape of the deflector would be simple to prevent the airflow to be trapped inside the aluminium frame.

Maybe some of you master aerodynamics study softwares or have good ideas of what's better to do ?

Thanks and sorry for the non clickable links
*edited after 5 post to have links ;-)


Last edited by sebcbien; 01-13-2021 at 08:42 AM..
  Reply With Quote
The Following User Says Thank You to sebcbien For This Useful Post:
aerohead (01-13-2021)
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 01-12-2021, 10:16 PM   #2 (permalink)
EV convert
 
oil pan 4's Avatar
 
Join Date: Jul 2011
Location: NewMexico (USA)
Posts: 9,037

Sub - '84 Chevy Diesel Suburban C10
SUV
90 day: 19.5 mpg (US)

camaro - '85 Chevy Camaro Z28

Riot - '03 Kia Rio POS
Team Hyundai
90 day: 30.21 mpg (US)

Bug - '01 VW Beetle GLSturbo
90 day: 26.43 mpg (US)

Sub2500 - '86 GMC Suburban C2500
90 day: 11.95 mpg (US)

Snow flake - '11 Nissan Leaf SL
SUV
90 day: 141.63 mpg (US)
Thanks: 215
Thanked 2,951 Times in 2,299 Posts
Glue semi flexible panels to the roof.
__________________
1984 chevy suburban, custom made 6.5L diesel turbocharged with a Garrett T76 and Holset HE351VE, 22:1 compression 13psi of intercooled boost.
1989 firebird mostly stock. Aside from the 6-speed manual trans, corvette gen 5 front brakes, 1LE drive shaft, 4th Gen disc brake fbody rear end.
2011 leaf SL, white, portable 240v CHAdeMO, trailer hitch, new batt as of 2014.
  Reply With Quote
Old 01-12-2021, 10:46 PM   #3 (permalink)
Banned
 
Join Date: Nov 2017
Location: Australia
Posts: 1,615
Thanks: 92
Thanked 1,297 Times in 908 Posts
Quote:
Originally Posted by sebcbien View Post
Hello,
First post here !
I've designed an airfoil profile to help reduce the drag of rigid solar panels mounted on top of campers / vans etc.
Sorry I cannot post links as I'm new

I already shared the designs here:
sprinter-source.com/forums/index.php?threads/93869/

and also on thingiverse:
Front: thingiverse.com/thing:4708973
Rear: thingiverse.com/thing:4719660

Those profiles can be printed with 3D printer and cut and assembled at the desired length.
Those profiles are straightforward and mimic a drop/airfoil profile.

I'm posting here because there is a more difficult problem:

rigid solar panels are preferred because they are more durable and more powerful by size.
They allow heat to escape under the panel and this geatly enhance the power output, a hot panel produces way less than a colder one.

So ..
With my profiles, I "solve" the front and rear drag, but there are two more edges, "inside" the panel:

Sorry I cannot post images or links, hope you will understand.

And if there was no problem with the cooling, I think the shape of the deflector would be simple to prevent the airflow to be trapped inside the aluminium frame.

Maybe some of you master aerodynamics study softwares or have good ideas of what's better to do ?

Thanks and sorry for the non clickable links
The front profile looks fine but I doubt the flow stays attached to the rear profile - I'd guess it needs to be much longer. However, very easy to test this with short tufts.

I don't know what you mean by 'inside edges'. If you mean the lower surface is not smooth, I'd place a cover under the solar panel and then use some vents to allow cooling air to pass above the cover. If that is the case, I can suggest how you'd do this.

Last edited by JulianEdgar; 01-13-2021 at 01:42 AM.. Reason: typo
  Reply With Quote
The Following User Says Thank You to JulianEdgar For This Useful Post:
sebcbien (Yesterday)
Old 01-13-2021, 05:13 AM   #4 (permalink)
EcoModding Lurker
 
Join Date: Jan 2021
Location: Belgium
Posts: 5
Thanks: 2
Thanked 1 Time in 1 Post
Quote:
Originally Posted by oil pan 4 View Post
Glue semi flexible panels to the roof.
Hello,
Thanks, but NOT a solution, sorry, too easy
It's about power and heat.
Heat cannot escape under a glued solar panel and overheat.
This gives solar panel with poor lifetime and poor power (power decrease a lot with heat, increase a lot with cool)
Flexible solar panels are limited in power by design.
That's why you see way more hard panels on van roofs than flexibles ones.
  Reply With Quote
Old 01-13-2021, 05:22 AM   #5 (permalink)
EcoModding Lurker
 
Join Date: Jan 2021
Location: Belgium
Posts: 5
Thanks: 2
Thanked 1 Time in 1 Post
Quote:
Originally Posted by JulianEdgar View Post
The front profile looks fine but I doubt the flow stays attached to the rear profile - I'd guess it needs to be much longer. However, very easy to test this with short tufts.

I don't know what you mean by 'inside edges'. If you mean the lower surface is not smooth, I'd place a cover under the solar panel and then use some vents to allow cooling air to pass above the cover. If that is the case, I can suggest how you'd do this.
Hello, as I'm new I cannot post pictures or links.

Yes, it's the lower surface that is not smooth at the start but the problem is mostly at the end, it's an aluminium U profile that traps the flow.
Cover under the solar panel it's not a solution either, as I responded in the previous post, heat is a major factor that has to be taken in account.

Please have a look at the last picture I posted here:
http://sprinter-source.com/forums/in...threads/93869/

As for the length, yes I understand, I also thought it should be longer.
The profiles are quite small (3cm height) what length would you suggest by experience ?
Keep in mind that they are vans and campers, it usually not go over 100kph for a very long time.

Last edited by sebcbien; 01-13-2021 at 08:43 AM..
  Reply With Quote
Old 01-13-2021, 05:30 AM   #6 (permalink)
Banned
 
Join Date: Nov 2017
Location: Australia
Posts: 1,615
Thanks: 92
Thanked 1,297 Times in 908 Posts
I suggested a cover under the panel and vents to allow cooling air to flow. That would be fairly easy to arrange. (But I was thinking of how the vents would work when you are moving, not stopped.)

Perhaps instead just use a gentle fairing that doesn't have to extend too far forward - make up a mock-up and tuft test to see if it retains attached flow. You could probably use dense mesh for this fairing to aid panel cooling.

Before making any changes to the rear end caps, I'd also tuft test these to see if they're working.

  Reply With Quote
The Following User Says Thank You to JulianEdgar For This Useful Post:
sebcbien (Yesterday)
Reply  Post New Thread


Tags
aerodynamic, camper, solar panel, van

Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com