Solar Panel Impact On Penthouse Heat-up

[Klompen]

My poor SMB with the penthouse is stuck for now in Phoenix with no shaded parking available. Even with all the window shades in place, awning window open and a 10" fan exhausting air out of a front window the van still regularly heats up to 120+ inside.

I had a brainstorm today about adding solar panels and wanted to see if anyone has experience with this. We currently have no solar panels and I can feel that there is a lot of the heating coming from the penthouse roof. My theory is that fixed solar panels on a rack would provide shade for the roof surface and ventilation space between the panels and the roof. Is this thinking at all valid?

Assuming that this would have a positive impact on the problem, what does it take to mount a rack on top of the penthouse? Is it necessary to disassemble the ceiling of the penthouse so that a bolt-through attachment can be done or there another way that can be done and still provide appropriate attachment?

[Scalf77]

The solar panel will add heat, a flexible panel mounted directly to roof would be the worse case. Hard panel mounted off the roof lets some air flow, but I still believe would be hotter. So if your doing it for shade I would say no.

-greg

I used to have thermocouples on my panels, I will try and dig up some old data logs showing temps.

[BroncoHauler]

Do you currently have a roof rack or at least some Thule/Yakima crossbars? If so, just add some plywood up there while parked and do an experiment to see if it helps or hurts. If you do this though, be sure to secure the plywood so the wind doesn't cause it to fly off and hit your van.

Herb

[Klompen]

Thanks, Greg. I wondered also about how much heat the fixed panels would radiate on the underside. Clearly flex panels attached to the roof would only make it worse.

[Scalf77]

I was logging temps of 140° on the backside of hard panels in 80° outside temps.

-greg

[Klompen]

Originally Posted by Scalf77

I was logging temps of 140° on the backside of hard panels in 80° outside temps.

-greg

WOW! So much for that idea!

[jamesc]

Flex panels attached to plywood on Yakima or Thule rack? I have no idea, but seems like the shade and 6 to 8 inches of the rack could help.

[arctictraveller]

Yesterday I placed a full roll of reflectix over the roof of my van as an experiment since I’m headed to the Nevada desert tomorrow. It was effective enough that I’ll take it with me and just weight it down with rocks or something while I’m camped. It lowered the inside overhead / headliner Temp about 20 degrees. Before, even with my air conditioner running I could feel lots of heat radiating from the overhead.

[Twoxentrix]

Most people place front windshield sunshade inside to help screen the sun- only issue with this is the reflection dramatically heats up the front windshield and produces extremely high temps - That heat doesn't go anywhere...stays inside.
I have about 2/3 of my pop-top covered by the solar panel & Thule box which do help keep temps down (mounted about 5" above the tops surface on an aluminess rack), but I also have a front windshield cover which mounts on the outside (it's black on one side & reflective silver on the other allowing me to use either) - When the van is in direct sun this outside cover alone keeps my inside temps down about 15 degrees compared to using a sunshade that sits inside the van.
We tried both scenarios one afternoon - about 2hrs with inside windshield shade & 2hrs with outside shade (BLACK SIDE FACING OUT). daytime temps were about 90 degrees, and we had the pop-top up with the 4 side windows unzipped about half way....15 degree difference measured by a thermometer approximately 2/3 of the way up and towards the back half of the van.
...This is just a pic of my front "outside" cover :

[ctb]

Two your van is so awesome! ...Another case of just in time threads...we have been looking at shades that go on the outside because th front heats up so much we wonder if no internal sunshade would be better...we also bought another "beach tent" from REI (lycra type material with four heavy duty elastic rope/tie downs)we plan to use to shade the van (better)...outside shade seems to be the quickest/easiest fix...

Ps Two, what brand is that shade? Looks perfect...