Author Topic: passive freon tracker (Read 10878 times)

birdhouse · « **on:** July 21, 2011, 03:41:26 PM »

i thought i'd start a new thread as to not hijack this one:

http://fieldlines.com/board/index.php/topic,145606.18.html

alright, i'm getting more and more intrigued! i've read about the zomeworks systems, and also found some info from a DIY version. it seems the type that just use the weight of the fluid to go from side to side (zomeworks) seem to work moderately well. my place is in a very windy area, and i doubt a large dampener would keep panels pointed at the sun all the time. without a dampener, i think these trackers would be all over the place. also dampeners seem to be hard to come by used and finding a cheap, large and sturdy one may be difficult.

sooo- seeings how i've got new panels in route, i think i'm gonna have a go at the type that uses the freon to build pressure behind a double acting hydraulic cylinder to track the sun. i'm guessing that the hydraulic cylinder would be strong enough to hold the panels in the desired location without a dampener even under pretty substantial winds. a small dampener could always be added if needed. i would also guess that it would react faster to cloud cover, and morning shift to the east. it just seems like a far superior way to track, though slightly more complicated.

cold temps may also make the tracker not work very well, thus a brace to hold centered during the winter may be needed.

my largest set-back for this project is the lack of knowledge of various refrigerants. and also sweating copper pipe to hold the refrigerant. i can sweat copper plumbing pipe just fine, but that typically only has to hold 30-60 psi. i think refrigerant can produce much higher psi when sitting in a closed loop of copper, baking in the sun at ambient 105d F.

i plane on using some sort of lubrication added to the freon to keep the o-rings in the hydraulic in good shape.

can anyone elaborate on this written by xeonpony?

Quote

For this idea you would use 300sus mineral oil as it must be soluble by the R-12 (Freon tm) How ever I would not recommend R-12 due to it's ODP value, R-152a or R-134a is readily available from air duster cans of all things with a bit of propane mixed in to assist in oil transfer so you can use mineral oil.

there's quite a bit i don't understand IE- "300sus" "ODP value" differences between 152a and 134a and propane....

any comments/criticism/info fully welcome.

thanks!

adam

Ungrounded Lightning Rod · « **Reply #1 on:** July 21, 2011, 06:12:56 PM »

"Dampeners" are also known as "shock absorbers". I bet a motorcycle shock would do the job just fine. (I wouldn't be surprised if that's what they used initially, too.) And a motorcycle shop would also have something you could use for the mounts.

If you don't mind using a flammable working fluid (which wouldn't bother me on an outdoor installation), LP gas is very cheap compared to other refrigerants and the fittings are easy to find. The boiling point of the propane component (the bulk of the predominantly propane-butane mixture) is -42.1 C / -43.8 F, so if a mercury thermometer is still working your tracker should be, too.

birdhouse · « **Reply #2 on:** July 21, 2011, 08:08:33 PM »

UGL-
i've got an extra set of forks from a honda XR-600. would have to remove the springs from them, but leave the dampening (shock) portion alone. i'm hoping with the hydraulic cylinder controlling the movement, that i wouldn't even need to use them.

so i did a little research on propane. looks like @

-10F 17.5 PSI
30F 53 PSI
110F 204 PSI

"i think" at all but the coldest temps, this should be plenty of power to push hydraulics, even if slowly. new problem becomes holding in 200+ psi on the side tubes when i get warm out. i know there are two different types of copper pipe L & M. one being thicker. i still don't know if the thicker of the two would hold in 200 psi. or if i can sweat them well enough!

this leads me to a question: does anyone know if black pipe (NG line) with the threaded ends would be easier to hold in this type of pressure?

i'm banging into walls due to my lack of knowledge in this realm.

any help/thoughts out there?

adam

Tritium · « **Reply #3 on:** July 21, 2011, 09:58:00 PM »

Copper pipe normally used for R-12 has the same safety factor as using propane since pressures are basically equivalent. I would silver solder or braze the copper just like for refrigeration use.

Thurmond

birdhouse · « **Reply #4 on:** July 21, 2011, 10:58:26 PM »

thurmond-
thanks for the info. the only brazing i've done was to seal shut cracks in a cast iron wood stove. i think i may stick with the silver solder idea... sounds much easier!

just so my idea is clear, i drew up a sophisticated CAD drawing to try to illustrate what i'm trying to accomplish...

adam

RP · « **Reply #5 on:** July 21, 2011, 11:01:12 PM »

In theory you could:

1. Go to Walmart, buy two cheap propane torches with the tanks

2. Cut off the brass stems under the burner and silver solder/braze on some 1/4" flexible copper refrigeration tubing

3. Connect the other ends of the two copper tubes to your hydraulic cylinder (using hydraulic fittings)

4. Paint the propane tanks black and mount them on the sides of the rack, open the valves and experiment away!

birdhouse · « **Reply #6 on:** July 21, 2011, 11:10:52 PM »

RP-
i hear ya, but i don't think i wanna go quite that rouge. plus i'm very nervous about just a soldered on some brass tubing. the 200+ PSI makes me want to overbuild, not wally world it. though a great idea for proof of concept!

i'd rather use actual hydraulic hoses, or at least fittings that thread together... then solder the threads shut. maybe i'm on the wrong track. i'm kinda a NooB to all this high pressure stuff. i can sweat pipes for water (40-50PSI) all day long, but this is a different ball game, at least in my head it is.

i know my drawing is lacking, but for those that can make sense of it i'd love any feedback!

adam

larryf · « **Reply #7 on:** July 22, 2011, 01:11:51 PM »

I'm short on theory here, but on the wally world propane torches, when one went in the shade, would the pressure decline quickly enough to create an imbalace or would it go into some kind of vapor lock?

Phil Timmons · « **Reply #8 on:** July 22, 2011, 01:25:27 PM »

Comparifying what I recall of the Zomeworks version --

They used two shock absorbers -- probably an intended "no single point of failure" in the design.

AND

The side tanks just fed back and forth to each other. When one got warm, it would go to "gas" and push fluid and gas to the far side, making that far side heavy and tilting the entire array, until that far side was also exposed to the sun and would balance.

That made the entire system sealed and could not leak, like a piston ring/wipe might in a piston-type hydraulic cylinder. So it all just worked by weight, which on the far outside edges of the array had a lot of leverage.

If I were doing a home hack, I might just use some old 30 pound freon cans (maybe you can get some from an A/C guy) and just use the threaded nozzle and valve that they come with to pipe or tube between the cans. Mount them on the outside edges of the array, with adjustable shades.

That should leave you with no moving parts other than the bearings it all rocked back and forth on.

Tritium · « **Reply #9 on:** July 22, 2011, 03:10:07 PM »

Adam you probably want something like on this page:

http://catalogs.johnstonesupply.com/3128_johnstone_202/full.asp?page=1350

Phosphorus/Copper/Silver Alloy. It is self fluxing on copper. You will need Oxy / acetylene if your lines are not really small though. 1/4" ti about 1/2" can be accomplished with a bernz-o-matic with mapp gas.

If you soft silver solder than you need to clean and flux everything very well.

Thurmond

XeonPony · « **Reply #10 on:** July 24, 2011, 05:01:24 PM »

You want 15% silphos as it is refered to, you still want to clean and pollish your copper joints, and when brazing you need a sweeping gas to prevent scale from forming, Nitrogen is the industry standerd but if you do some research and learning first you can use propane as the sweeping gas, I've don it tons of times.

Ungrounded Lightning Rod · « **Reply #11 on:** August 06, 2011, 02:48:36 AM »

Quote from: Phil Timmons on July 22, 2011, 01:25:27 PM

Comparifying what I recall of the Zomeworks version --...

The side tanks just fed back and forth to each other. When one got warm, it would go to "gas" and push fluid and gas to the far side, making that far side heavy and tilting the entire array, until that far side was also exposed to the sun and would balance.

That made the entire system sealed and could not leak, like a piston ring/wipe might in a piston-type hydraulic cylinder. So it all just worked by weight, which on the far outside edges of the array had a lot of leverage.

Note that the zomeworks system connected the tanks at the bottom. That way you are pushing fluid around and only have to boil a little bit of it into gas to provide the push. If it were connected at the top you'd be pushing gas around and have to boil a whole tank of propane or whatever to shift the weight. This would take much of the day. Not practical.

You can simulate this by hanging a full tank on one side of the array, an empty (but purged) tank on the other, valve down, and hooking them together. (Don't forget the angled sunshade-mirror gadget at the outside of each tank to hook the sun onto it for sunrise turn-around and differentially shade the tanks appropriately as the panel approaches pointing at the sun.

Now for the hydraulic piston version you want to put the tank hose connections at the top to get gas, rather than liquid, into the actuator.

On the other hand if you want

birdhouse · « **Reply #12 on:** August 06, 2011, 03:34:24 PM »

ULR-
i'm not very interested in the zomeworks type of tracker. just seems like it might not be the best choice for a high wind location.

in regards to the hydraulic cylinder version- i'd think you would also want to have the hoses connected to the bottom of the copper tubes. that's where the (presumably) sus300 mineral oil and other liquid would be(propane, or r-12 or r-134/5). the pressure in a single copper tube has to be the same weather it is liquid or gaseous, and i'd think that a hyd. cyl. would be more prone to leaking if powered by gas rather than liquid.

i've started to do my homework on this new project. there are plenty of new double action hyd. cyl. around with a 20" throw and 2500+ psi rating, and 5000lbs rating for around $100 or so. i think i'd prefer a long throw to be able to connect the hyd. cyl. further outward on the panel mount, and thus decrease forces the hyd. cyl sees. hoses look to be 30-40 each for long ones. i've found all of the above with 3/8" NPT connectors, which would be very easy with standard copper plumbing stuff.

i've figured out the correct brazing rods, and learnt about sweeping gas. i'm getting ready to start buying stuff, or atleast welding the frame up. now i need a stong pole, and a big hole, and lots of concrete...

does anyone remeber the hotwheels cars that turned one color under hot water, and another under cold?? if i could get some paint to go from black (for winter when psi in the system is low), to white (for summer when psi is plenty high) to paint on the copper tubes, that would be ideal!

adam

XeonPony · « **Reply #13 on:** August 10, 2011, 06:02:07 PM »

sus is a thicknes rating your old R-12 freezer will be using 150 to 200 sus oil for lubrication with hydrocarbons you need a thicker heavier oil, ie the 300 rating.

ODP is ozone depleation petential
GWP is Global warming potential

R-12 has a high ODP and a low GWP
R134a & R152a has a high GWP and low to non ODP.
Hydro carbones such as Iso-Butane(R-600a) and Propane(R-290) have low GWP and zero ODP

R-290 will have lower pressures under high heat too making it the best choise over the above listed and will do well in winter, it is a drop in for R-22 systems as well in behavier, so it will be good down to -20C or better.

Look for the P&T chart for R-290 and you will see the pressures related to temp for it. here is one I found in Imperial units: http://www.glacierbay.com/ptchartpropane.asp

I personaly feel you have a very prommising solution for the wind issue that most passive trackers suffer from!

birdhouse · « **Reply #14 on:** August 10, 2011, 08:48:51 PM »

xeonpony-
thanks for the encouraging words! i've been researching quite a bit, and trying to remember all this stuff! it's hard as i'm not used to this sort of field. HVAC is def. my weak point in the construction realm!

thanks for the info on the mineral oil ratings! i think i'll take your advice on using r-290 (propane) as the fluid. i can get my HVAC guy to vacuum my pipes and can add the propane myself!

how important is it to use a sweeping gas? will the scale really hurt the hydraulic cylinder? also, how on earth do you use propane as a sweeping gas without blowing yourself up? that seems sketch to me, but i'm sure there are "safe" though non- OHSHA approved ways of doing such things.

also, since (i hope) i've got you on the line, where do you think the flex pipe from the hyd. cyl. should tie into the copper tube. i was thinking the bottom, as that is where the mineral oil/propane/liquid is. thoughts??

thanks again!

worst part is, i've got soooo many half finished projects out at my ranch, that i don't think i'll be able to implement this until the fall. though i can get all my pieces and parts together, and begin brazing stuff, and welding up the frame ect. the setting of the pole, and concrete work hopefully will happen before the fall!

adam

XeonPony · « **Reply #15 on:** August 11, 2011, 11:55:44 AM »

I would agree with the bottom of the pipes, that way you have the fluid oil mix acting on the cylinder!

Scale of copper is like sand paper it will wear down all your seals amazingly fas,t and plus it will plug any restriction in the pipe, so it is, in my books, vital to prevent it!

To use propane as a sweeping gas:

step 1: Get a pipe cap the same size as the tubing you are working with and drill a tiny hole 1/8" or smaller, this is where the gas will be flared off as it leaves the pipe.

step 2: Get some 1/8 or so tubing and solder it to some thing that can be affixed to the propane supply (The velocity inside the small pipe will make flash back impossible) and attach it to the pipe to be protected.

step 3: Blow out all the air by giving the pipe a burst of propane,e then, throttle back immediately & place the cap with the 1/8" hole on it, adjust flow so that you can barely see any coming out the 1/8 hole then wait for a good gust of wind, then light the gas escaping from the 1/8" hole, it should be burning like a candle! Allow it to burn for a minute to ensure no air remains inside the pipe.

At this point you can start your brazing with no scale or oxide formation in a safe manner, since we are burning the gas as it leaves the pipe it can't build up any were for an explosion to happen, same with the small feed tube, the gas velocity is so high no flame front can form to cause a flash back!

birdhouse · « **Reply #16 on:** August 11, 2011, 12:00:53 PM »

xeonpony-
thanks again for the info. can CO2 be used as a sweeping gas? that would be really easy for me to use my tank from my mig welder!

adam

XeonPony · « **Reply #17 on:** August 11, 2011, 12:24:43 PM »

CO2 can be used but the industry and my self would rather see Argon, Nitrogen, Helium used not as preffered but works wonders is Propane as it will actualy remove oxides!

For oven brazing they use Nitrogen with 5% Hydrogen mixed in for the same reason!

larryf · « **Reply #18 on:** August 17, 2011, 12:12:08 PM »

For those who have been following this for awhile, I did as RP suggested and got two cheap propane torches plumbed to a hydraulic cyliinder. So far it has not worked, as there is a oneway valve in the torch. With the tank removed and the controller open, the pressure in the cylinder will not bleed off, so there is no way for the pressure to get back to the tank. I will not dismiss this yet, but will have to get rid of that oneway valve. $:-\$

birdhouse · « **Reply #19 on:** August 17, 2011, 09:12:51 PM »

larry-
bummer about the check valves! maybe you can remove them?? or drill a hole in the flapper??

i'm glad i'm not the only one going down this road, though my ride is a turtle. i've wrangled up free copper 1" pipe. still need to order the hydraulic cylinder, hoses, and schrader valves.

after learning about brazing pipe with sweeping gas ect. i think i'm just gonna have my HVAC guy do it for me. plus he has the device to pull the vacuum on the system before i fill it with propane. i give him enough business, i'll bet he does it for me for free. then if i get a leak, i'll call him up to my ranch for a service call...

i'm still struggling with how large to make the panel mounting frame. i've got two 196w from sunelec, and two 195w evergreens with broken glass that i wrote about here:

http://fieldlines.com/board/index.php/topic,145487.0.html

but i think i'm going to make it wide enough to fit two more panels of roughly the same size for future buys.

good luck larry!

adam

redtick · « **Reply #20 on:** August 23, 2011, 04:17:54 PM »

I don't have a valve in front of me, but if memory serves me right.

If you unscrew the tube from the valve. There is a small machined nut in the end of the tube, where the flame flashback check ball is enclosed.

But it has been a day or two since I have had one apart.

birdhouse · « **Reply #21 on:** November 16, 2011, 06:56:36 PM »

it's been a while, but i'm slowly moving forward on this idea.

i've gotten my cylinder, just ordered the hyd. hoses, have all my copper fitted up.

sus300 mineral oil was recommended as a lube to mix with the refridgerant to keep the gaskets on the hyd. cylinder in good shape. after some research, Alkybenzene Oil is talked of being superior for a lube.

any thoughts on this?

getting my ducks in a row before i call up my HVAC guy to do the brazing/filling for my project.

thanks!
adam

XeonPony · « **Reply #22 on:** November 17, 2011, 12:43:24 PM »

In a refer system the Alkylbenzen would be the winner, but with what you are building water tolerance is crucial! So stay with good ol 300sus Mineral it won't turn into acids over time if water gets in it!

mathelm · « **Reply #23 on:** August 13, 2012, 08:33:09 AM »

Any progress?

birdhouse · « **Reply #24 on:** August 13, 2012, 11:31:38 AM »

math-
sadly, there has not been any progress. the copper rigs have been sitting in my shop where i stare at them every day, and yet i have done nothing to further the project in damn near a year.

sure i can say i've been busy, which is true... http://www.fieldlines.com/index.php/topic,146976.0.html

i did finally get my two broken evergreens installed! they put 6A into my 24v battery bank... not bad for free!

but is does seem a shame. especially when i've got 500w of panels that sit IN the shed. these panels were destined to be mounted to the freon tracker, and probably will end up on it at some point. funny part is, and i find this hard to say, but, i don't really need the power. my solar/wind inputs provide more than i can use, and have the battery bank at float by early afternoon most days anyways. i can only fire so many framing nails a day, and yet it still keeps up with that!

i do need to get my butt in gear, and get after this long wait listed project. maybe being put into the public eye will get me motivated for it!

adam

News:

Author Topic: passive freon tracker (Read 10878 times)