Solar Tracker Project - Page 7

Xringer · 05-27-10, 10:12 AM

I think it's about $10 a pound.. Like high quality steaks..

I do like the fact these are smaller.. The right size for an old guy..
Years ago, I think maybe a 125 watt panel was larger (and harder to handle).

Right now, I'm storing the panels in the living room, standing up, stacked
and leaning against the wall. It's amazing how little room they take up..

Got to go look at some steel U-channel at HomeDepot today..

Edit:
Got the U-channel yesterday (Super-Strut B1400HS), the larger size was bigger and stronger,
but was way too heavy for my taste.

If this turns out to have too much flex, I'll go get the larger size.

Today, I picked up four 4"x4"x8' posts. I will try to use them like a portable mount,
so I can get rid of the old deck that I've been using for a mount these last 20 years.

Kinda like this, but with 4 legs, each 7 feet long.. Made of HEAVY 4x4 posts. (Pressure treated).

Xringer · 05-29-10, 04:32 PM

Got some work done today.

Removed the drive and took the post off the old dish deck..

Found the left-over steel was too long. Had to saw about 1" off it.
It's about 4x4" with 1/2" thick walls. Took a while with my old badly worn SawsAll blades..

Here is where I stopped when the thunderstorm started..

I'm not sure if it's too far south and will be blocked by the house or garage,
but it's going to stay there until we get a good solar-day, so I can see
if it's in a 5 or 6 hour spot..

This evening, I got the 2 steel cross sections done.. Hard steel bed frame angle iron is hard stuff..
It's all cut and drilled for mounting to the disc and has some holes spaced out at 38"
for holding the two vertical 10 foot super-struts.
The mounting holes in the panels are spaced at 38".

I also made sixteen 1.5"x1.5"x square aluminum 'washers' (.25" thick) that will sit on the U-channel,
to keep the bolts from pulling the panel sheet metal down into the channel.

I'm having problems with the 1/4-20 bolts. Everything I have is either too short,
or too long. They bottom-out inside the channel. (Unless it hits a hole).
I might just saw off the too long ones..

Xringer · 05-30-10, 03:52 PM

Got them out in the sun.

The tracker is working fine and we got first light
on the mount at 10:30 AM and shadows started in at 16:30.. A solid 6 hours.

I was using a 100W 120VAC bulb for testing. It put a light load on the panels.

Open circuit is 79V. With light bulb load, it was 77.2V. The bulb looked like
it was putting out 40 to 60 watts. Hard to say.

Oddly, the bulb stayed on a couple more hours after the shade came in..
There was no direct sunlight on the panels. Just what filtered in from the trees to the west.
No bight spots of light on the panels.
The voltage slowly dropped from the 70s down to 50 volts at 18:30 PM.
The bulb looked (and felt) like it was at 20-30 watts when I shut it down..

This pic was taken around 17:00, when the shadows were setting in.. The lamp was still seeing 77 volts..

Edit: Adding one last pic..

If you use these Home Depot struts, make sure to get bolts that will fit
under the lip on the backside of your panels. Not too long (you can't install them) or too short ( they won't reach the Block-Nut).

I used a spacer sandwiched between the strut and the PV, so the PV wouldn't bend, into the U-channel.

jwxr7 · 05-31-10, 11:50 AM

NIce work! Do you think it will hold up well in high winds?

Xringer · 05-31-10, 03:06 PM

Quote:

Originally Posted by jwxr7

NIce work! Do you think it will hold up well in high winds?

As it is now, I suspect it wouldn't do real well in high winds.
However, it takes a hurricane to get much wind in the back yard.

The two struts have a slight bend in them (flexing down),
so I'm thinking of adding some reinforcement. Maybe two more struts..

I'm waiting for my resistors to show up tomorrow, so I can build my little heater array.

Today, I decided to use some of the power that's just wasting away.
I ran an extension cord down to the boiler in the basement, and
connected it to the 250W heating patch on the boiler.

The Resistance of the patch is 59 ohms and the loaded voltage is 79.7 Vdc.
So the power is only about 107.66 watts.
367.3512 BTUh isn't much, but it's better than nothing..

Once I get my 10 ohm heater in there, I should be getting closer to
magic 500 watts that I'm looking for.. (crossing fingers)..

Xringer · 06-01-10, 05:02 PM

They look pretty good for 'used' resistors. Had to dig around for a few 1/4|20 nuts and washers,
but all the measurements came out very close to 40 ohms.

In parallel, these will be 10 ohms, and should be a good match to the (series) panels.

The plan is to mount these on an aluminum plate (maybe 11x5x0.5 inches)
and epoxy the plate onto the top of my boiler.
I wonder if I can find some cheap heat-conducting epoxy. I'm not sure how well JB Weld would work..

Just to the right of that clean spot..

I will need to make a sheet metal cover to fit over the heater array,
it will be insulated to keep the heat inside, so it can be absorbed
downwards, into the boilerplate and into the water near the top.

Each resistor is rated at 250 watts, so the total dissipation is going to be 1KW.
So, driving them with just 500 watts of PV, should allow them to last at least 30 years..

I've been trying to tweak the tracker to less sensitivity to clouds etc.
And I think maybe the array is picking RFI. We live a few within a few
miles of a powerful AM station. I tried adding a small ground rod..
But a thunderstorm this afternoon reminded me that I need a real
ground rod and some heavy connection cable..

I'm considering using RG8 type coax for routing the power.

And, I'm starting to think that PL-259/SO-239 connections
might be better (and cheaper) than N-connectors..
I think the PL-259 (also called UHF connectors) would handle current
better, since it has a much larger center pin. With more contact area.

Using this kind of cable, means that I would have the negative side
of the panels at earth ground, and run the + on the center conductor.

This should allow me to build a grounded bulkhead plate to install at the entry point to the basement.
This one of the old standard Ham Radio types of lightning protection.
(Double Female S0-239)

NiHaoMike · 06-02-10, 09:37 AM

Quote:

Originally Posted by Xringer

And I think maybe the array is picking RFI. We live a few within a few miles of a powerful AM station.

Have you thought about building a resonant antenna to capture some of that energy? Maybe use copper pipe and homemade air core capacitors to get a high enough Q factor.

Xringer · 06-02-10, 09:04 PM

I've actually been thinking about adding some by-pass capacitors (0.01 uf) across the
12V power & motor lines, and the four wires coming from the optical module.
But mostly, I'm sold on the idea of installing a good ground at the base of the mount.

As to RF capture of power, I'm afraid that we don't have the land area or the copper
to install an antenna capable of capturing usable power.
The station is about 1.9 miles from here and the inverse square law tends to eat up
a good bit of the power at that kind of range.
Besides, a single inexpensive PV panel could harvest a lot more power for a LOT less money.

Anyways, I had the top cover off the boiler this afternoon and I checked the heat patch using the IR scan pistol..

The main gauge said the boiler was about 140 deg. And a scan of the top read out as about 140 deg.
But when I scanned the 107.66 watts (of PV) on the heating patch, it showed up as 210 degrees!
The steel close around the patch was in the 170-190 deg range.

If the 10 ohm load is a good match for the panels, and I can get around
500 watts, sunk into my water storage, this project might end up being
very productive..

Daox · 06-03-10, 07:13 AM

Is there insulation around the boiler? You show the picture of the sanded patch, but I can't tell whats around it. I'd think that this would be a great way to boost efficiency. However, I'd be surprised if there wasn't some there already.

Xringer · 06-03-10, 08:01 AM

This is the spot.. Above the big fire-box. Front-to-back & between the weld nubs.

It does have pretty good insulation. Testing with the 250w pad (using 120VAC)
showed some heat gain. So it was over-coming the losses.

I plan to do a lot more insulation on the pipes coming out the back,
I just have to make really sure that it has zero water leaks first..

If I can get near 500w into the water, I'm sure the positive gain will be excellent. (fingers crossed)
If they aren't, I'll be doing some super-insulation on the whole system..

I' know there's a sizable loss from the floor contact, since I can measure
floor-heat from the boiler. It falls off as you move away from the boiler area.
I plan to inject insulating foam underneath, to keep the heat off the pad.

In the summer, the hot water mostly stays near the top. And, there is almost no circulation inside the water jacket. (Since the pumps stay off).

If the results are unsatisfactory (after final insulation), I'll start thinking
about just getting a small tank, that I can heat without incurring a lot of loss,
and shut down the Tarm all summer..

05-27-10, 10:12 AM	#61
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 115 Thanked 250 Times in 230 Posts	I think it's about $10 a pound.. Like high quality steaks.. I do like the fact these are smaller.. The right size for an old guy.. Years ago, I think maybe a 125 watt panel was larger (and harder to handle). Right now, I'm storing the panels in the living room, standing up, stacked and leaning against the wall. It's amazing how little room they take up.. Got to go look at some steel U-channel at HomeDepot today.. Edit: Got the U-channel yesterday (Super-Strut B1400HS), the larger size was bigger and stronger, but was way too heavy for my taste. If this turns out to have too much flex, I'll go get the larger size. Today, I picked up four 4"x4"x8' posts. I will try to use them like a portable mount, so I can get rid of the old deck that I've been using for a mount these last 20 years. Kinda like this, but with 4 legs, each 7 feet long.. Made of HEAVY 4x4 posts. (Pressure treated). Last edited by Xringer; 05-28-10 at 04:16 PM.. Reason: Reporting the news

05-29-10, 04:32 PM	#62
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 115 Thanked 250 Times in 230 Posts	Got some work done today. Removed the drive and took the post off the old dish deck.. Found the left-over steel was too long. Had to saw about 1" off it. It's about 4x4" with 1/2" thick walls. Took a while with my old badly worn SawsAll blades.. Here is where I stopped when the thunderstorm started.. I'm not sure if it's too far south and will be blocked by the house or garage, but it's going to stay there until we get a good solar-day, so I can see if it's in a 5 or 6 hour spot.. This evening, I got the 2 steel cross sections done.. Hard steel bed frame angle iron is hard stuff.. It's all cut and drilled for mounting to the disc and has some holes spaced out at 38" for holding the two vertical 10 foot super-struts. The mounting holes in the panels are spaced at 38". I also made sixteen 1.5"x1.5"x square aluminum 'washers' (.25" thick) that will sit on the U-channel, to keep the bolts from pulling the panel sheet metal down into the channel. I'm having problems with the 1/4-20 bolts. Everything I have is either too short, or too long. They bottom-out inside the channel. (Unless it hits a hole). I might just saw off the too long ones.. Last edited by Xringer; 05-29-10 at 11:21 PM..

05-30-10, 03:52 PM	#63
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 115 Thanked 250 Times in 230 Posts	Got them out in the sun. The tracker is working fine and we got first light on the mount at 10:30 AM and shadows started in at 16:30.. A solid 6 hours. I was using a 100W 120VAC bulb for testing. It put a light load on the panels. Open circuit is 79V. With light bulb load, it was 77.2V. The bulb looked like it was putting out 40 to 60 watts. Hard to say. Oddly, the bulb stayed on a couple more hours after the shade came in.. There was no direct sunlight on the panels. Just what filtered in from the trees to the west. No bight spots of light on the panels. The voltage slowly dropped from the 70s down to 50 volts at 18:30 PM. The bulb looked (and felt) like it was at 20-30 watts when I shut it down.. This pic was taken around 17:00, when the shadows were setting in.. The lamp was still seeing 77 volts.. Edit: Adding one last pic.. If you use these Home Depot struts, make sure to get bolts that will fit under the lip on the backside of your panels. Not too long (you can't install them) or too short ( they won't reach the Block-Nut). I used a spacer sandwiched between the strut and the PV, so the PV wouldn't bend, into the U-channel. Last edited by Xringer; 12-29-10 at 01:03 PM.. Reason: Adding pic

06-01-10, 05:02 PM	#66
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 115 Thanked 250 Times in 230 Posts	The resistors came in.. They look pretty good for 'used' resistors. Had to dig around for a few 1/4\|20 nuts and washers, but all the measurements came out very close to 40 ohms. In parallel, these will be 10 ohms, and should be a good match to the (series) panels. The plan is to mount these on an aluminum plate (maybe 11x5x0.5 inches) and epoxy the plate onto the top of my boiler. I wonder if I can find some cheap heat-conducting epoxy. I'm not sure how well JB Weld would work.. Just to the right of that clean spot.. I will need to make a sheet metal cover to fit over the heater array, it will be insulated to keep the heat inside, so it can be absorbed downwards, into the boilerplate and into the water near the top. Each resistor is rated at 250 watts, so the total dissipation is going to be 1KW. So, driving them with just 500 watts of PV, should allow them to last at least 30 years.. I've been trying to tweak the tracker to less sensitivity to clouds etc. And I think maybe the array is picking RFI. We live a few within a few miles of a powerful AM station. I tried adding a small ground rod.. But a thunderstorm this afternoon reminded me that I need a real ground rod and some heavy connection cable.. I'm considering using RG8 type coax for routing the power. And, I'm starting to think that PL-259/SO-239 connections might be better (and cheaper) than N-connectors.. I think the PL-259 (also called UHF connectors) would handle current better, since it has a much larger center pin. With more contact area. Using this kind of cable, means that I would have the negative side of the panels at earth ground, and run the + on the center conductor. This should allow me to build a grounded bulkhead plate to install at the entry point to the basement. This one of the old standard Ham Radio types of lightning protection. (Double Female S0-239) Last edited by Xringer; 06-01-10 at 06:55 PM..

06-03-10, 07:13 AM	#69
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	Is there insulation around the boiler? You show the picture of the sanded patch, but I can't tell whats around it. I'd think that this would be a great way to boost efficiency. However, I'd be surprised if there wasn't some there already. __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

05-31-10, 11:50 AM	#64
jwxr7 Apprentice EcoRenovator Join Date: Dec 2008 Location: mid michigan Posts: 191 Thanks: 0 Thanked 0 Times in 0 Posts	NIce work! Do you think it will hold up well in high winds?

06-02-10, 09:04 PM	#68
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 115 Thanked 250 Times in 230 Posts	I've actually been thinking about adding some by-pass capacitors (0.01 uf) across the 12V power & motor lines, and the four wires coming from the optical module. But mostly, I'm sold on the idea of installing a good ground at the base of the mount. As to RF capture of power, I'm afraid that we don't have the land area or the copper to install an antenna capable of capturing usable power. The station is about 1.9 miles from here and the inverse square law tends to eat up a good bit of the power at that kind of range. Besides, a single inexpensive PV panel could harvest a lot more power for a LOT less money. Anyways, I had the top cover off the boiler this afternoon and I checked the heat patch using the IR scan pistol.. The main gauge said the boiler was about 140 deg. And a scan of the top read out as about 140 deg. But when I scanned the 107.66 watts (of PV) on the heating patch, it showed up as 210 degrees! The steel close around the patch was in the 170-190 deg range. If the 10 ohm load is a good match for the panels, and I can get around 500 watts, sunk into my water storage, this project might end up being very productive..

06-03-10, 08:01 AM	#70
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 115 Thanked 250 Times in 230 Posts	This is the spot.. Above the big fire-box. Front-to-back & between the weld nubs. It does have pretty good insulation. Testing with the 250w pad (using 120VAC) showed some heat gain. So it was over-coming the losses. I plan to do a lot more insulation on the pipes coming out the back, I just have to make really sure that it has zero water leaks first.. If I can get near 500w into the water, I'm sure the positive gain will be excellent. (fingers crossed) If they aren't, I'll be doing some super-insulation on the whole system.. I' know there's a sizable loss from the floor contact, since I can measure floor-heat from the boiler. It falls off as you move away from the boiler area. I plan to inject insulating foam underneath, to keep the heat off the pad. In the summer, the hot water mostly stays near the top. And, there is almost no circulation inside the water jacket. (Since the pumps stay off). If the results are unsatisfactory (after final insulation), I'll start thinking about just getting a small tank, that I can heat without incurring a lot of loss, and shut down the Tarm all summer..