Solar Panel Cooling

Novaz

Have been doing my continued research before buying a system i have seen videos and comments about how a PV panel is more efficent
when it runs cooler
does this mean that all those desert arrays that have hundreads of panels are missing out on a vast amount of power
is there not a case for some kind of mist or spray system to be employed to keep the panels cool
if the panels were equipped with a catchment system the loss of water could be kept at a minimum
as i am looking to purchase land with water close by would it be possible to run a pump from the stream or water source to the array
and then return the water after cooling in underground pipe back to the source maybe a pump could be run off its own PV panel so as not to lose energy from the main system
I guess people with more solar experience can provide the reasons this cooling is not done .
Thanks
Roy

Cariboocoot

Re: Solar Panel Cooling

Forget it; it's a losing proposition.

More energy is required to remove the heat from the panel than is gained by removing that heat.

Physics can be a real pain sometimes.

BB.

Re: Solar Panel Cooling

The amount of panel electrical efficiency improvement is pretty tiny--Here is an article that shows the improved efficiency:

http://www.engineering.com/ElectronicsDesign/ElectronicsDesignArticles/ArticleID/6123/Photovoltaic-Thermal-System-Achieves-86-Efficiency.aspx

Attachment not found.

That little green rectangle in the middle of the day is electrical efficiency increase claim by Sundrum. The big orange spikes is simply the hot water collected by the system.

SunDrum Solar

So--My 2 cents, if you want solar hot water (can actually be a good source of energy savings for heating/hot water), go with solar thermal collectors.

A general rule of thumb is ~40 square feet of collector per person for hot water and maybe 80 sqft if you live in northern climates.

Solar thermal is not "easy"--It is plumbing, controllers, pumps, water storage, mixing valves, possible drain-back/antifreeze system for hard freeze climates, etc.

Some older threads on the forum about cooling solar panels and solar thermal projects:

Cooling Solar Panels for Improved Power Output
Solar Panel Cooling
Solar Shed and other Solar Thermal Links

A good place to start reading is Home Power Magazine... They have a free past issue online--and have a lot of articles you can read for free. I don't always agree with them and their reviews--but they are a fun and enlightening read:

Home Power Mag

With stand alone heat pump water heaters--Solar Electric+Heat Pumps is giving solar thermal a run for its money--Even for some Off Grid solar folks (solar thermal water based systems can be a pain to install/maintain).

General Electric Geospring Heat Pump Electric Water Heater
GE Geospring Water Heater Testing
Nyle Geyser Heat Pump Water Heater

-Bill

stephendv

Re: Solar Panel Cooling

Novaz wrote: »

does this mean that all those desert arrays that have hundreads of panels are missing out on a vast amount of power

Thin film amorphous panels are sometimes used in very hot environments because of their lower power loss- also helps that desert land is cheap so the larger space required for thin film.
With a cell temp of 60 degrees C a poli or mono panel would produce about 15% less than STC rating, whereas an amorphous panel would produce 7% less. So a bit of a gain.
This only matters if you care about summer or annual solar production, like if you're grid tied. For most off-grid homes it's actually better to have a panel with "bad" thermal characteristics so that it'll produce more in winter (when you really need it) and less in summer, when you're throwing power away.

Any active cooling system is too costly and complicated compared to the gains and the cost of more PV.