Solar Panel Concentrator/Tracker

[skibum13]

I just tried finding the web site I saw a while back on a Solar PV Concentrator/Tracker that looked very interesting. I did find this site that is very, very similar to the design I had in mind.

http://www.ida.net/users/tetonsl/solar/solarhom.htm

Instead of using it to collect and transfer heat, I was planning on having a Solar Panel installed where the collector is, so all the reflected light would hit the Solar Panel and increase it's energy output. Obviously, the quality of the Solar Panel would have to be very high to be efficient with the increase magnification of sunlight. But I didn't know exactly how much light I could direct onto the Solar Panel before I a) broke it; b) melted it; or c) it stopped being efficient. I would assume some sort of heat exchanger is required because the temperature of the solar panel directly correlates to the efficiency of the panel. And I don't think that it would need to be nearly a large as the one in the link above.

It seems like with a solar concentrator, there would be a higher energy output, but the energy output would be limited by the maximum amout of sunlight a solar panel can convert to energy. Has anybody done any experiments with solar concentrators? Any advice?

The majority of solar concentrators I've seen on web sites are trough-looking devices with a slightly parabolic mirror on each size of the panel. I think using the design in the link above will put a lot more sunlight on the panel.

[Bob Boyce]

Concentrators cook the PV panels and cause premature degradation/failure. It also voids any factory warranty the PV panel may have, and believe me, they can tell when a PV panel has been cooked by a concentrator. There are loads of used cooked PV panels on sale on eBay that came from commercial solar concentrator farms. You can tell because they tend to turn brown. There are high priced PV panels specially made for use with concentrators, and they tend to be built on heat exchangers for cell cooling. Even with that they don't live long enough for economical payback.

Bob

[skibum13]

I would assume it's the heat that is generated by the concentrator that cooks the panels. It seems like a heat exchanger could be utilized to transfer the majority of that heat away from the panel. I think temperature is going to be the biggest determinant, but let's not consider that for right now.

Assuming a proper operating temperature was maintained, how much sunlight could one panel utilize. I guess there would be an equation that would tell me exactly how much, but I'm not at a point were it needs to be super precise.

If I had reflectors that were each the same size as the solar panel, then I could roughly multiply the amount of sunlight hitting the panel by the number of reflectors I have. So if I have 4 reflectors positioned to reflect on a solar panel, then the solar panel would be receiving roughly 4 times as much sunlight. What I would like to figure out is how much light one panel can use efficiently.

BTW, I tried emailing you the other day at your realmcity address. Do you still use that one?

[Bob Boyce]

The chemistry of PV solar cells are formulated for a solar energy level of 1KW per square meter. As you increase the solar energy, efficiency drops due to several factors, temperature being only one of them. Even with backplane cooling, the PV cell surface temperatures rise to above operational specifications and the surface of the PV cells are permanently damaged. This already happens at normal solar energy levels, just happens slower, which is why PV panels drop off in output over time. The thinner the active layer (as in thin film technologies) the more rapid the decay. Unless you have a lot of money to throw away buying replacement PV panels much more often, I would stay far away from using concentrated solar energy on them.

I had to discard my old realmcity.com email address due to spam. It was posted by so many people on so many sites globally that my spam email count went to over 1000 emails a day. I have a new realmcity.com email address, I just don't post it anywhere to stop this from happening again. Just remember my first name and the rest you already know

Bob

[kevinsatterfield]

[Bob Boyce]

[kevinsatterfield]

[pertyfly]

[ElectroGasMan]

[12volt dan]

On the tracker end of things has anyone seen this tracker?

http://www.redrok.com/led3xassm.htm

This is a simple,low cost and fairly reliable tracker thats capable of runing the old 8ft dish actuator. I've run one and found it to be just what the doctor ordered. I don't use it any more because of the wind risk I've encountered when the array is pointing the wrong way but other than that it's my choice for a tracker

[spinning-magnets]

I hadn't thought I'd ever get PhotoVoltaic panels, but in the back of my mind, it seemed a possibility. After reading some of the posts on OU, I think I probably won't. (Thanks!)

However I plan on living in snow country after retirement, so I've been doing my homework on solar heat to ease my heating costs.

One of the dozen options I've bookmarked is a solar "hot-air" panel made from a discarded (or new) glass door.

It is boxed in with 1" X 6"s on the sides, plywood on the back, with a thin plywood sheet suspended in the middle and the suspended dividers front covered with aluminum sheetmetal (the center "flow divider" doesn't go all the way to the bottom). It's top is leaned against the bottom of a southern facing window, and the flow divider extends into the room. Sun shining through the glass heats air that rises into the room, and cooler air is drawn into the back half of the panel. The drawn-in air flows down the back half, makes a U-turn at the bottom, and flows up as its heated.

These odd-looking hot-air collectors can be stored most of the year, and only deployed as needed.

I had thought If I ever made some of these, it would double their effectiveness if they tracked the sun by rocking a little to the east and west. Instead of setting them on a window sill and sealing the connection for a few months, the top would have to have two flexible hoses to route the hot and cool air into a window sill adapter. I visualized a central pole lengthwise under the panel. The bottom of the pole sits on the ground, and the top of the pole is supported by an "A-frame".

Next I had to figure out a good way to slowly raise the eastern edge throughout the course of the day, or lower the western edge. I was willing to re-set a device once a day if neccessary.

I visualized a vertical PVC cylinder under the top western corner with a connected rod passing down the center of the cylinder. The bottom of the rod has a weighted float. The cylinder is filled with water about 8:00 at night, which raises the float and tilts the panel to the morning sun in the east. A bolt screwed into the side of the cylinder prevents the float from rising higher than the mid-point. A tiny orifice or valve begins dripping the water from the bottom of the cylinder into a pan, and at about 9:00 in the morning the water level has dropped to the point where the float will begin dropping, and then the weighted float begins pulling down on the top/west corner, and by about 6:00 PM it bottoms out facing mostly to the sun setting in the west. At 8:00 PM, pour water from the pan into the cylinder and it starts all over again. In freezing weather I'm sure I could find a better fluid than water, but thats the basic idea.

I can imagine putting up a windbreak on each side, but even if an occasional breeze causes it to rock, it will return to the proper angle. I haven't built one yet, but I think it would be cheap and easy to put together with free junk. just an option for thought...-Ron