[chbla]

Not sure if there is another thread on the experiment @GaryBIS did, but here is a new video about actively cooling a solar panel, I think it's related:

 

[GaryBIS]

Not sure if there is another thread on the experiment @GaryBIS did, but here is a new video about actively cooling a solar panel, I think it's related:

Hi,
I like the tests this guy does and how well he explains them - I'm subscribed, but somehow I missed this one.

Seems like a well done test, and I'd not argue with his results.

I do think he goes a bit lite on the area of harvesting the heat from the airstream used to cool the panel for space heating.
If you look at the numbers, the heat energy you could potentially harvest is as much or more than the PV panel itself harvests!

If you look at 1 sqmeter of panel, under ideal conditions, there is 1000 watts of solar incident on it (kind of amazing how it works out this way). Of the 1000 watts, the 20% efficient PV panel outputs 200 watts of electricity. This leaves you with 800 watts of heat. Solar thermal air heating collectors (for space heating) are about 40% efficient, so if you could extract as much heat as a well designed solar thermal panel, you would get 800*0.4 = 320 watts of usable heat for space heating. If the solar heat collection was less efficient than 40% (which is likely), but even with a pretty good drop in efficiency, you could harvest as much useful heat energy as the PV panel is producing in electrical energy (and make the PV panel run a little more efficient via the cooling air).

There is some material out there on this - here is one... and another...
I've thought about giving this a try on my home PV array, but its kind of far from the house for air ducts.

Gary

 

[chbla]

@GaryBIS thanks for your thoughts! How would you make use of the heat?

For heating water, I think a direct approach through water cooled panels, is probably not
the way to go. As he mentions, you would have problems in colder temperatures and I assume
that the temperature is not enough anyway in this case.

Solar air heating might be an option though.

I once wondered if it is feasible to "charge" a PCM module (heat storage) during the day, e.g.
if you're running the diesel heater on low anyway, and use that heat at night, so you could turn off
the diesel heater.

There is a German (sorry) site around that topic: Die Solar - Luftkollektor / Warmluftkollektor Bauanleitung ✓ which is quite interesting.
He is heating his home on sunny winter days:

 

[GaryBIS]

@GaryBIS thanks for your thoughts! How would you make use of the heat?

For heating water, I think a direct approach through water cooled panels, is probably not
the way to go. As he mentions, you would have problems in colder temperatures and I assume
that the temperature is not enough anyway in this case.

Solar air heating might be an option though.

I once wondered if it is feasible to "charge" a PCM module (heat storage) during the day, e.g.
if you're running the diesel heater on low anyway, and use that heat at night, so you could turn off
the diesel heater.

There is a German (sorry) site around that topic: Die Solar - Luftkollektor / Warmluftkollektor Bauanleitung ✓ which is quite interesting.
He is heating his home on sunny winter days:

Hi,
I think the most practical way to use the heat from cooling the pv panels is to use the heated airstream for space heating. All of the examples I've seen were space heating. Air heating collectors are simple and forgiving - you don't have to worry about leaks or freezing.

Interesting video. I like air heating collectors - my shop is heated with one.
A friend and worked on an optimal solar air heating collector based on side by side tests of alternative designs..

Gary

 

[chbla]

@GaryBIS thanks for the link, that's quite interesting.

Did you ever look into PCM as an option for the van? To save excess energy?
I'm not sure what kind of weights/dimensions would be necessary.

I also thought about using the water tank, which is under my bed (100L) as heat/warmth storage
during the night.

bobilvans.co.uk has some nice heat exchangers, I'm using the hybrid version.