My Solar business partner and I have been experimenting with this "Solar Cooling Jacket" (more photos here) to try and reduce (in our Hot Georgia Summer Sun) solar PV panel heat. Our thinking is that if we could reduce it by 30 degrees F, then the heat-caused, voltage flow reduction will be mitigated (new technology may mitigate if not eliminate this). Hence, we could cost-feasibly increase the panel's net output during the summer. And yes, the panel could be easily integrated into a system that runs heated coolant into some sort of waste-heat recovery process (i.e., my building's hot water heater).
We used off-the-shelf parts and donated sealants from this fine company. We theorize that the jacket could be mass-produced at no more than $65/unit and add no more than 25 pounds to a solar panel. The added cost would then be factored into the payback cycle arising from the translation of the panel's increased voltage (hence, electricity) into dollars (for my 10KW array, I pocket $.13/KWH spared retail power and $.08/KWH in reverse-meter credits). If all goes well, the increased yield would make the $65 back well within the panel's normal payback cycle (my 10KW system is projected to pay for itself within 14 years).
We tried this panel out on my array (here's another shot) using rubbing alcohol this past August 27, 2011, on a 96 degree day. Alas, the best we could achieve was a 10 degree reduction. But that was, as you can see, using only a 100% passive system (relying on the alcohol to naturally rise to the radiator then be cooled by it and, resultingly, flow back down the jacket's "arteries").
Our next step would be to integrate a low-cost but durable DC "water pump" to circulate the coolant. Optimally, it would work right off the panel's own DC-electricity output (no need to run when there's no sun). Short of that, we'd power it independently. Other ideas would be (and we designed the cooling jacket for this) to string such jackets together and thus run a centralized water pump to flow all of the panel jackets off the roof and into a common heat dump (one big radiator), but of course that runs up the expense and how many showers a day do I take (hence, people think of motels and institutional uses here).
We deem this invention public domain, thus constituting "prior art" within the meaning of U.S. patent law, and thus in giving this design away we in return ask for nothing but the wisdom of the crowd (hence, crowdsourcing) to help improve it. We invite DC motor vendors to contact us, and yes, we accept donations (this entire site is a non-profit, self-funded undertaking to simply try and improve Solar PV for the masses). Send suggestions to firstname.lastname@example.org
Manufacturers please note: Our Gillis Spings, GA location is an ideal place to consider. Just 33 minutes from Dublin, GA, home to MAGE Solar, a large aluminum manufacturer, and -- in Dublin as well as in Swainsboro and other nearby cities/towns -- a boat load of empty factories and cheap labor to run them (we're talking China-level costs).