Parabolic Trough Solar Collector Water Heater 6

[@Zeemike1]

Nice job of engineering Andrew...and good workmanship too.

[@ancelgray]

Thanks for the kudos. Andrew

[@XoshBitt]

Incredible work! Really inspirational. Thanks for making the video and showing us what you made. All the best!

[@DPaquette]

Selling it is a good idea but posting this as open source will also help contribute to the betterment of humanity. Please consider doing this.

[@ancelgray]

Hello DR Paquette. Do you think there is enough interest and ability out there to put the open source effort required for this? This design is really for the advanced do-it-yourselfer. (?)(?)(?)

[@DPaquette]

Yes i do as a good portion of the population have been working in IT in one form or another for many years. With those careers (programming, database config, electronics design & integration, etc.) I am sure that it will be just fine for these people.

[@ancelgray]

Well, I have been approached for plans by a few people and I have helped some build a few. But the demand has been low. So it is worth mentioning that I will help someone construct one of these solar heaters if they are interested. AAG

[@ancelgray]

3) Another advantage is that this system can be mounted on the north or east side of your home's roof, thus leaving more space for photovoltaic solar panels.

[@ancelgray]

1) Yes, Grant. On a clear summer day at 4 liters/min flow, one gets a 10 degree Centigrade drop across the heat exchanger. That is roughly 2.7 Kilowatts, or about 9000 BTU/hour. I have not made the measurement yet in winter because I need to mount the system up on my roof for it to be able to "see" the sun. 2) The main advantage over regular commercial systems is that it will work in the wintertime when it is cold (it is insulated with a vacuum) and windy (comm. systems don't work then).

[@ancelgray]

Well, I finally totaled everything up and since I did several generations of troughs, drive mechanisms, electronics, etc., the cost (for me and my experimentation) turned out double to what I was thinking, a little more than $4000. I still think that a lower price than this can be attained if one starts with a "fine-tuned" plan and does not get distracted with experimentation (don't get me wrong, the experimentation was fun and entertaining). The system is now running month after month like an appliance with no attention now. My electric bill this month (april) for my 1800 sq ft all-electric home was just $68. Wow. So when I put photo-voltaics on my roof in front of my water heater (the heater will be mounted on the NORTH side of my roof), I need to install a smaller system than originally planned! Andrew Ancel Gray

[@Ailanto]

Hello Andrew. Congratulations for your project. I want to build something similar to it, but the main motivation i have for it is to achive a low cost water heating system and share it, so people and industry move to a more efficient use of resources. My hypothesis is that price per square meter of reflector should be lower than price per square meter of heat absorber (normally copper). What do you think of that?

[@ancelgray]

Jorge W Yes, I agree. However, the absorber system will probably come out to be the same price since it is a simpler system. But for the absorbers themselves, reflectors win the price competition. For my system though, the absorbers have a vacuum surrounding them, which make them work year round, as well as near the Arctic Circle! Flat plate systems will not work in the windy cold winter, even with sunshine!

[@ancelgray]

Hello George! Thanks for the kudos. Yeah, it has turned out very well. Much better than I had originally thought. Sure, put as many links to these videos as you like! Perhaps we can get the world heating water with the Sun! Andrew Ancel Gray

[@ancelgray]

Jozef, I have the water circulate through a heat exchanger in a 50 gallon water heater tank. This heats up the water tank for showers, dishwashing,etc. It has dropped my electric bill by about $50/month. No, I am not producing electricity with thermo electric generators. That would require that water be boiled and regulated through a generator. That is a much bigger operation than what I have! Andrew Ancel Gray

[@Ailanto]

Let me give you and advice. Elevation angle adjustment is not necessary. Installation should be calculated to provide enough energy in winter when conditions are worst. The elevation according to sun elevation in winter should be ok for the rest of the year, since deviation will be desired to avoid overheating in summer.

[@ancelgray]

Yes, Jorge, this can be true. That is, if your spot to mount the system is oriented exactly East-West, then the second rotation-axis would not be necessary. But if your roof faces, say, SouthWest, then the dual axis system is really nice. Also, the dual axis system can be mounted in the "North-South" orientation so sun exposure happens ALL DAY. And near the Arctic Circle (e.g., northern Canada), a dual axis system can get sun exposure for 16-20 hours per day (a single axis system cannot do this).

[@sauliaalto2835]

All I can say is - Very nice work!

[@ancelgray]

Thanks Sauli! Andrew

[@ancelgray]

Thanh, If you orient the system purely North-South or purely East-West, then a one axis system would be fine. If you orient the system purely East-West, then you could manually tilt the system with the seasons. If you orient the system purely North-South, your focusing error would have to be small as the sun went further south in the wintertime (the sun would not be directly overhead in winter). This orientation would be similar to the giant commercial installations in the Arizona desert.

[@ancelgray]

Thanh, I have used 1/2" hydraulic hoses from Northern Tool to make the flexible plumbing. These hoses are REALLY tough. So far no problems. I am using a 12V TopsFlo TS5 15PV pump to circulate the water. It is about $70 on amazon. So far no problems. I have not used it to circulate water to and from the roof of my 3 storied home, however. It should be OK since the circulation pipes will be FULL of water (as much pressure downward as pressure needed to pump upward). I will let you know.

[@ancelgray]

Thanh, I have not added up all the costs yet (I have all the receipts in a drawer), because I still need to mount my system on my roof. I will be doing that in a few months and I will let you know. George Plhak claims that each trough costs about $150 to make, so mine cost about $200. Then you need approximately $250 in electronics, $200 in framing and $100 for a heat exchanger to put in an existing electric water heater. So ROUGHLY, lets say $1500-$2000 (Like I said, just ROUGHLY).

[@johng.3740]

For water heating purposes this system is adequate but, if you wish to run a small solar steam operation higher temperatures and pressures would be needed. It may be possible to construct a transparent vacuum box using the glass that is used in double paned windows. Double paned windows have a vacuum between the two panes of glass. If we can increase the distance between the two sheet of glass then we can insert steel pipes inside and then evacuate the system. A little bit of engineering and calculations have to be performed in order to determine the maximum temperature achievable.

[@DocScience2]

Double paned windows DO NOT have a vacuum between the two panes of glass. If they did, they would implode under the pressure. double windows often use a gas inside that does not transfer heat as fast as air does, but the gas is needed to equalize the pressures. For a test, I siliconed two pieces of glass together, and first put in spacer blocks somewhat equally spaced inside, to hold the sides from imploding. It worked ok. That is what would have to be done to put the space between 2 panes of glass under a vacuum.. Calculate your air pressure which is 15 pounds/ square inch for normal air pressure at about sea level.. . take a sheet of glass 1 foot by 1 foot and support it on all the edges. . Air pressure is the equivalent of placing 2,000 pounds of weight on that piece of glass..

[@johng.3740]

@@DocScience2 According to wikipedia some double pane windows do have a vacuum, to be precise the lowest air pressure achievable with commercial equipment. en.m.wikipedia.org/wiki/Insulated_glazing Other double pane windows have inert gas in-between the two panes. I think it would be best to ask the vacuum window manufacturers why the glass doesn't break www.pilkington.com/en/us/products/product-categories/thermal-insulation/pilkington-spacia It does appear that true vacuum glazing is only a recent development, using small supports running from on side to the other all throughout the window. onlinedigeditions.com/publication/?i=228085&article_id=1830961&view=articleBrowser&ver=html5 So wikipedia needs revising and I was mistaken

[@johng.3740]

Ok, so to support a vacuum in the solar system he may need to use thicker glass OR thick high strength plastic (like bullet proof glass or plastic), or thinner glass and plastic with supports running from one side to the other www.tssbulletproof.com/blog/bullet-proof-glass-laminate-acrylic-polycarbonate/

[@ancelgray]

This leaves all of the South and West sides open for photovoltaic panels. However, Thanh, it would be neat to compare how the evacuated tubes work vs. the evacuated concentrated parabolics when it is cold outside. That is why I built this system (so it would heat the water to 155F in the winter). Andrew Ancel Gray

[@schoolhouseofmusic]

Andrew, how/where did you make/buy your black vacuum seals that allow the troughs to move? They seem like a critical part. Also, how hard is it to maintain a vacuum? Really nice job. You and George are teaching us a lot!

[@ancelgray]

s-h-o-music, The black seals are Fernco P1056-215 2 x 1-1/2 pipe couplers. I got them at Home Depot. Here they are on Amazon: www.amazon.com/s/ref=nb_sb_noss?url=search-alias%3Daps&field-keywords=+Fernco+P1056-215 Here they are in the diagram: modelofreality.org/SolarFocalTube.jpg I tried some other brands, and Fernco seemed to be the most heat resistant. So I would be careful if substituting other brands. No, it is not hard to maintain the vacuum. I initially pumped down the vacuum chambers to 28 in-Hg about four months ago, and it is still holding at about 25 in-Hg. I would expect both Helium and Hydrogen Molecules (H2) to be able to diffuse through the plastic, making it necessary to pump it down annually I would expect. Yes, a thanks to George for getting all of this started. I probably would not have started this project myself without his 5 or 6 generations of experimentation with the trough design. Finally, the vacuum seals really do not "allow the troughs to move". The troughs rotate on top of the clear plastic tubes. The black seals simply hold the troughs in place at the ends (I put in some aluminum rub washers in between too.) Andrew Ancel Gray

[@ndenman420]

Build a very well insulated thermal battery with a heat exchanger; you could heat your water and home. I know you live in texas; a cooling dominate climate. When your themal battery hits a temperature of 180 - 200 degrees you could divert the heat into a thermocouple. You could operate the thermocouple at a higher temperture (assuming regulations permit). Thermocouples are not efficient; they are eaiser than heat engines (excluding a stirling engine).

[@mostlymessingabout]

i have also been thinking of a one axis system today as well. all in my head and no where near as clever as this. my main issue was also the flexible plumbing which can be a failure point at high and low femperatures. i guess your system must require a pump to circulate to the main water as this would be below your roof.

[@yonkromis7883]

Can You orient them East to West? Save the trouble of tracking adjust weekly

[@CharlieSolis]

Excellent job! This is truly great work you’ve done! I’m currently in the process of designed something very similar. What are the numbers for how much energy you’re collecting? Like btu/day collected? Surface area of collection? Have you considered putting the whole system on a slight angle, lower on the south side higher in the north side, so you could fit more troughs in the same footprint? Oh also what would you estimate the build cost at this point? Thanks again for sharing your success! I hope my build comes together looking as nice as yours!

[@DocScience2]

I hope that he give us an update on how well things have worked in the long run. I find his design very impressive, with a lot thought going into it. I am thinking of how to reduce the amount of work involved to make a simpler design and I have a few ideas. He explains in one of his comments at the very bottom of this list, that you can reduce the complexity a bit by using one pivot. This is a link to his comment. kzbin.info/www/bejne/qp2lg6OHm8t8eKM&lc=UgxWqgiBnY3BdKQBuq94AaABAg - - - - (1)-If you design just one bigger reflector, you eliminate wasted spaces between the reflectors. (2)-Design the parabola edges to go at least a couple inches above the center tube. (3)-Then you can put one sheet of plastic, or polysheet, or glass, across the whole thing to protect and keep the reflector cleaner. (4)-There will be less t's and joints interconnecting all the tubing. (5)-I have no interest in creating steam, as it will be harder on the connecting seals, and other parts of the system. (6)-because of this, I can make the center tube larger, so that it takes care of times when the parabola is not precisely facing the sun. The suns rays will then be reflected to the surface of the collector tube, instead of missing it. It takes care of problems where or if the reflector was made a bit off shape from an exact parabola shape. (7)-To further take care of alignments when the reflector is not exactly aligned up with the sun, make the center collector tube sort of flattened. You can use 1/2 inch copper tubing and put a "U" shape by doubling back, or use 2 copper pipes side by side to be the center collector with the ends joined at each end. A simpler method is to have 3 lengths by looping back and forth, so that you have a wide but narrow collector pipe to take care of alignment difficulties or irregularities. . (8)-When you are using one large unit, it is advisable to have this arrangement of piping for a larger center collector pipe. (9)-When you are not intending to make steam, by putting one poly tube over this center collector tube arrangement, you can still get reasonable efficiency without the need to evacuate it. (10)-The reason why this should work better than a flat plate collector is because no matter what your climate, you are considerably reducing the overall footage of cooling surfaces, and I do not see the need to extensively insulate the reflector surfaces. - - - Let me know if you are able to read this comment OK. Give me your thoughts and suggestions. -

[@CharlieSolis]

@@DocScience2 I definitely have to give some of the credit for inspiring the design I ended ip going with on my solar collector to Andrew Gray. Watching this video really helped me finally make the executive decision on which of the many ideas I had to go with.

[@DocScience2]

= @@CharlieSolis = Thankyou for the fast reply. Have you posted any pictures of your setup and descriptions ??

[@CharlieSolis]

@@DocScience2 I’m still awaiting materials. And hashing out the turbine build process. It’s super cold out where I am right now so I’m going to start assembling things in the summer.

[@sfdidg]

wonderful 🎉❤

[@purebokety]

Great work thanks for sharing

[@climacosouza9520]

Dear AncelGray - WOW - Have you ever tried to reheat some thermal fluid such as molten salt (boiling point 350o C) or Therminol VP (boiling point up to 560o C) or even soybean oil (boiling point 300o C)? What were the results in liters per hour and what was the outlet temperature?

[@ancelgray]

I also paid about $500 for an EcoSmart 24 Kwatt tankless ("demand-only") backup water heater so ALL my solar water heating is used (and is free). If you have two tanks instead of using a tankless backup, then THE FIRST SHOWER IS NOT FREE (you pay for the electric backup tank first). Since I live alone, that is NOT good. So my TOTAL cost in closer to $2000 than $1500.

[@abdulolaogun1946]

Amazing tech 👍🏻🤓

[@yonkromis7883]

Great job

[@mostlymessingabout]

Hi, do you mind telling us how much all this costs? aside from the cool factor, do you think it is cheaper than a fixed evacuated tube system? i would imagine the alternative to have say 20 or so pipes and also go up to 160F.

[@glsmith20]

Have you ever figured out the btus of your system ? What are the advantages over the fixed commerically available systems ? Thanks for posting

[@JozefTrubac]

what is the use of this system ? Do you produce electricity with thermo electric generators ?

[@UUttis]

Looks good, have you built this after some plans? If so where are they available? Im mostly wondering what you have used for a reflector? I bought some reflective film i think its used for acvarium use for mine but im afraid the will be ruined pretty quick if run unprotected.

[@ancelgray]

Decieved Well, I have not yet offered any complete plans yet, just bits and pieces. I built mine by altering George Phlak's plans: www.ffwdm.com/solar/solar-index.htm I used mirror stainless sheet metal for my reflectors because we get large hail here in Texas that can destroy plastic sheets.

[@coachgeo]

I believed you use the Dan Rojas homemade vacuum tube with clear PVC. Im guessing it does not hold vacuum constantly from leaks thus the vacuum pump to keep it at a set value. If I am correct how is the clear PVC holding up? Did you use the type with UVR protection or the standard type?

[@ancelgray]

Coachgeo, I used clear polycarbonate tubing (not PVC) with UV protection. It is holding a vacuum fairly well. Over a period of 6 months, a small amount of diffusion has taken place, but I suspect that there are no leaks.

[@coachgeo]

Do CPVC etc. type fittings work with the Polycorbonate tubing? Many would love it if you did a video on how you made the Evac tubes!! Or am I blind and dumb and can't find the video you did on this already :D

[@ancelgray]

coachgeo Coachgeo, CPVC and polycarbonate are not compatible. I used 1-1/2" copper for my focal tube, then converted to CPVC to go into the frame with a CPVC x Copper union (Genova 53046). The polycarbonate is attached to the central focal pipe with "rubber" Fernco Couplings. Now coachgeo, if you are really going to make some of these focal tubes, then let me know. I have many "unpolished" videos and photos to help out that will explain it perfectly (not ready for prime time yet). You can get this done if you wish. You just need to be able to braze copper. Here is a diagram of the central tube: www.modelofreality.org/SolarFocalTube.jpg Andrew Ancel Gray

[@ancelgray]

coachgeo You are correct in seeing that I have not made a vacuum tube video yet, or a solar water tank video, or a solar water heater roof mount video. I am working on it! Right now I am trying to get solar panels (PVs) installed on my home! So much to do!

[@coachgeo]

Glad to know Im not blind :D As you consider what vid to make next... consider that there are many vids about most everything in your list with the ol' cat skinned a different way in each... but there is only one in all of video land about building Evac. tubes and it was not clear tubes nor Poly like you used. (thus all different fittings?)

[@yonkromis7883]

What would it take to extend it a lot a make steam etc

[@beebob1279]

do you have a video showing it work?

[@ancelgray]

4) Next, this concentrated parabolic system cannot overheat. If the temperature of the collector gets above say, 165F (74C), then the controller simply moves the frame out of sun. With regular commercial flat panel systems, overheating is a problem in the summertime, when frankly, you do not need so much heat. If a parabolic system's controller fails, the concentrators still do not overheat, because in 30 minutes or so the sun has moved enough to stop the concentration of heat. Therefore, I have used cpvc (chlorinated PVC for hot water) piping in all my hookups, a big financial savings (copper is really expensive these days). Cpvc piping can be used here because the danger of overheating is gone. And let me tell you, piping with cpvc is MUCH easier than dealing with copper tubing. Andrew Ancel Gray

[@The_Engineer_Naturopath]

Hi, I read your experiment with great of interest. I am trying to generate steam using a parabolic solar concentrator trough. Can you help us build a system with energy storage and hydraulic system. Zak

[@ancelgray]

Zak Kouloughli Well, yes I can. I now have tracking electronics if you need them. The electronics track the sun using the time of day, not using a "sun detector". So the parabolic collector is always aligned towards the sun, clouds or no clouds. It has two two motor controls (double axis), two thermistors, and two pump controls.

[@The_Engineer_Naturopath]

Zak Kouloughli I an interested. Can you also provide the hydraulic system and the energy storage? We are trying to achieve aaround 300 degres Celsius of steam.

[@ancelgray]

Zak Kouloughli My system is a computerized solar water heater controller for hot water (not steam). Your system is going to be much larger. I used small dc motors to move my parabolic troughs. My motor controller outputs go +12/-12V, so you would have to use these to switch your hydraulic valves. And you would have to supply your own energy storage.

[@The_Engineer_Naturopath]

Hi Andrew, can you help build for me a solar system using a parabolic trough, tracking, hydraulic system and energy storage system. The purpose is to achieve high heat to generate steam.

[@ancelgray]

Finally Thanh, I like my parabolic solar tracking water heater perhaps better than the evacuated tubing ones because I can mount my system on the North (or East) side of my roof. Here is a pic (change "0RG", "SLASH", "D0T" and "g1f" to correct symbols). modelofreality^0RG SLASH SolarArray D0T g1f Let me know what you think.

[@philindeblanc]

Is that Fabio??!!

[@davidparkhurst7508]

Hey Andrew, Where did you find the glass vacuum tubes? I am looking, but they all seem so expensive. Thanks.

[@ancelgray]

Sure, David, I used UV stabilized Polycarbonate Tubing. I got my polycarbonate tubing indirectly from a company called Futurplast. The tubing is PCT0023-clear 2-1/4" ID x 2-1/2 OD Polycarbonate Tube (8 feet long). The description on their website (futurplast D0T ca) does not indicate UV stabilization, so I got them to send me a UV stabilization certificate: www.futurplast.ca/newpl.pdf A local plastic company ordered from them for me. I think I paid about $50 apiece for (4) Eight foot lengths.

[@TheRossRants]

hi, I am hoping to start on a smaller system to heat my home built hot tub. I am intending to use the troughs to heat water during the day ( probably 4nos 1m long troughs) and a 500w wind turbine to charge batteries for an electric heater to run through the night. These batteries will also run the circulation pump. This way the tub runs 24/7. Do you have any tips and advice for me on building the collectors, any common problems you came across, etc? cheers, Ross

[@ancelgray]

TheRossRants Sure, Ross. 1) Study the outside edges of my trough design. Notice that I put support under the mirror surface along the edges and that the mirrors do not sag. Other designs on the web sag in between the parabolic supports. This makes the light miss the focal pipe. 2) Also notice that the troughs can twist with time and weathering and that I have used an "anti-twist bar". 3) I decided to use a smart tracker that knows where the sun is instead of a "Sun Detector" using a light sensitive photocell. The problem with the sun detecting photocell is that it wanders with cloud cover. (However, if you combine the "Sun Detecting Photocell" with a smart interpolater you can get it done, but I decided to use a "know-where-the-sun-is-at-all-times" controller. 4) George Plhak has a lot of knowledge that you can use to build your system, including an "e-book". That is how I got started. Use his videos and e-book (adding mirror support along the trough edges like mine) to find out how to build them. kzbin.info/www/bejne/bHiQmZdpgp6sisk 5) Ross, I used PV solar panels to charge batteries to run the system at night. This seemed to work well. I am not familiar with how complicated a wind/solar combo would be. And there are heat-pump-water-heaters available that are more efficient that straight electric heaters. Good luck, and let me know what you think. Andrew Ancel Gray

[@TheRossRants]

ancelgray Thanks Andrew. Would love to have a system like yours .... maybe I'll get there eventually :) I've seen a few of George's videos as well as the Dan Rojas ones.I like the idea of having it computer controlled with "know-where-the-sun-is" tracking rather than Photocell tracking, but as you say it might be good to combine the two as a check system. wind/solar combo is easy stuff. It uses a hybrid charge controller so power from both panels and a turbine can be used at the same time to charge batteries safely. There are many different units on ebay like this one:-@271692130903 What sort of wattage do the motors, computer, etc use for your array (trying to judge battery and panel size requirements)? Once I get into this project properly (might be a while) I'm sure I'll have many more questions. Is it ok if I contact you with them for your experiences? cheers,Ross

[@ancelgray]

TheRossRants Sure, Ross. The Alix 1D computer (along with my driver electronics) draw about 1 amp@12VDC. The two 12VDC motors that tilt the frame and troughs draw 1-2 amps@12VDC. The pump also draws about 1 amp@12VDC for a max total of 6 amps@12VDC (usually a lot less though). Let me know what you think. Here in Austin, there is not enough wind to make windpower economical. I have a 7 kilowatt PV array on my home. The PV panels along with my parabolic water heater do the trick. Andrew Ancel Gray

[@TheRossRants]

ancelgray well, as my old geography teacher used to say - the UK gets weather, everyone else has a climate :) lol.The last 2 weeks have been pouring rain and 75mph winds. Today, clear skies, blazing sun and dead calm/zero winds. 6amp draw!? That's a lot less than I was expecting, so that's really good. Not sure if I can get an Alix over here, but I can probably find something similar - maybe a raspberry pi. We'll just have to wait and see :) Thanks for all your help. cheers,Ross

[@TheRossRants]

forgot to ask, do you pump water through the mirrors to heat directly, or do you use a heat exchanger fluid at a tank somewhere else? As mine is purely for my hot tub, do you think I should pump water direct or use a tank/heat exchanger set up? Ross

[@BeckmanMJ]

I am looking into building something similar for an experimental farm. Do you see this being possible in the Northern states? Like Montana?

[@ancelgray]

BeckmanMJ, According to insolation maps, Montana generally gets as much solar exposure as we do here in Austin (except far NW Montana). rredc.nrel.gov/solar/old_data/nsrdb/1961-1990/redbook/atlas/serve.cgi So since this design is insulated with a vacuum chamber, yes, it will work in Montana just fine. If you put this design on the ground be sure to orient the axes of the troughs East-West. If you put this design on a roof, be sure and orient the axes of the troughs North-South. The North-South orientation is overheat-proof. The East-West orientation maximizes solar exposure (but can overheat in the event the controller fails).

[@BeckmanMJ]

Thanks so much! Super excited for this! How is yours working in the winter? Do you have a link to explain more of the design. I understand the basics, but for starters i dont understand the vacuum chamber.

[@ancelgray]

BeckmanMJ BeckmanMJ, Well, the frame is not yet mounted on my roof (I'm workin' on it), so it cannot really "see" Mother Sun because it is shaded by my tall home this winter. However, early one morning it was near freezing (34F) and the sun was on it for only about 30 minutes and the temperature of the focal pipe was 80F (a 45F degree increase in just a few minutes). The pump surely came on. I suspect that it's going to work just fine in Winter. Here is a diagram of the vacuum chamber: modelofreality.org/SolarFocalTube.jpg I have adjusted some of the pipe lengths to accommodate the wider end caps, but you will get the general picture. I have used UV-stabilized polycarbonate tubing for the vacuum chamber, since here in Texas we have large sized hail coming down every once in a while. The polycarbonate has a good light transparency, especially in the infra-red. Let me know what you think. Andrew Ancel Gray

[@CabrioDriving]

Does this technology make sense in 2016 compared to 20% efficient pv panels?

[@ancelgray]

To Cabrio Driving in the Alps: Well, I put BOTH on my home. I filled the South and West sides of my home with PV's, and put the parabolic water heater on the North side. The parabolic heater can be put on the north side since it is mounted on a dual axis tracking frame! Now... I know you can mount PV's on frames on the north, but the water heater is so much more efficient (~80%), that it is much more worth it, while the PV's, maybe not! So with BOTH the parabolic water heater and our 7 KWatts of PV's, our home is now completely energy neutral (it generates slightly more total energy than we use). But to answer your question, this design is probably not commercially viable unless it was produced with economies of scale, and perhaps the controller migrated over to a Raspberry Pi, for example. However, the MATERIALS themselves aren't that expensive, so it was the ultimate do-it-yourselft project for the intensely green person! (So I built it!) Andrew Ancel Gray see modelofreality d0T 0rg slash PV d0T jpg

[@CabrioDriving]

Hi Andrew. Thank you for your detailed answer and your time. How efficient this heater is on a (a) semi-cloudy (b) cloudy day? Is it not effective then? Can it heat water if there is no direct sun due to clouds? What is the temperature of this central, heated pipe on a sunny day, semi-cloudy day, cloudy day?

[@ancelgray]

Cabrio Driving in The Alps: The heater does fine on a semi-cloudy day, but on a full cloudy day, not much heat is generated (unless during the hot summer, then some heat is created, even on a full cloudy day). The temperature of the central pipe depends on the water tank size and how fast you pump water through the pipe. But with 4 liters/minute (1 gal./minute) and with a 60 gallon tank, the temperature of the central pipe AND the 60 gallon water tank together (on a sunny day) quickly gets to 150F/66C and the system turns the array to the North. Of course, the water can be BOILED on a hot summer day if one allows it, (which I DO NOT!). Andrew Ancel Gray

[@GeertDroid]

Wat app do you use to control the system by remote ?

[@ancelgray]

Geert, Well, I have written a control program in C on the FreeBSD computer. This program uses solar-time to position the troughs into the sun. In addition, I have an interface to Apache Web cgi-scripts written in C to create a "browser control web site" that can be run on any smartphone browser or on FireFox/SeaMonkey. The buttons on the "control web site" can activate the motors/pump and all data is displayed like temperatures, angles, etc. Andrew Ancel Gray

[@boatdude10]

ancelgray have you posted the code for the program,"

[@ancelgray]

Randy Desnoyers Randy, I have not posted the code for the program. It is comprehensive. However, I have made available the complete FreeBSD 7.0 Flash drive, code and all for the price of the flash drive. You must have an ALIX 1C/1D/1E to run it though. And you must have interface electronics too. I will make electronics available as soon as I finish the copper PCB board. Andrew

[@boatdude10]

still waiting on it

[@ancelgray]

Randy Desnoyers Randy, you are building a parabolic project?

[@dmeskill2]

Wow. Do you have plans available?

[@ancelgray]

Duncan. I do not yet have plans available, though am considering doing so. Tell me, do you think that you could build a parabolic system like mine if given plans and provided electronics?

[@dmeskill2]

Yes absolutely. If you decided to sell a kit, that would be even better! Really like the idea of a sun following system, not only for solar thermal but also pv cells (have you tried that). How have the vacuum tubes been working for you? I've heard that they don't hold their seals well esp. with constant temperature fluctuations? Thanks again for sharing. VERY impressive video!

[@ancelgray]

Duncan Meskill I have considered making kits (because that would be the right thing to do), or simply putting everything out there in detailed plans. The electronics would take a knowledgeable technician to check them once assembled, so I probably would have to provide finished electronics. Also, the center pipes and frame require a skilled welder to complete, so center pipes would also have to be optionally provided. What do you think of these options? Would you build one of these systems if I provided the plans? Which skills do you possess? The vacuum seal is fine. Of course, helium and hydrogen (and other atoms) diffuse through the plastic so that the vacuum declines from approximately 29 inches of Mercury to about 25 inches of Mercury over a period of about 6 months. I should point out though that the vacuum is not the critical component of this system. Studies have shown that just COVERING the collector pipes (protection from wind) is nearly identical to pulling vacuum. The only place where this would NOT be true would be a system utilized in the Arctic/Antarctic Regions. There, a vacuum would indeed be helpful! The temperature fluctuations do not seem to affect the vacuum seals. Once the rubber gets heated by the sun once or twice to 150 F, the rubber "sticks" to the copper/polycarbonate so much that it can be difficult to pry loose. This becomes a very good seal. Solar tracking on PV cells indeed makes them more efficient. However, I am not sure that it is cost effective for PV's like it is for solar water heating. A solar water heater only takes about 4 square meters. PV systems take much more area than that. You see, a solar water heater can be 80-90% efficient. That makes solar tracking economical for solar water heaters. However, PV's are only about 15% efficient. It makes more sense to simply increase the PV area, rather than using solar tracking on them. Andrew Ancel Gray

[@TheRossRants]

ancelgray You could consider different levels of kits/plans. A simple system for beginners (like me) and then more complicated dual axis systems for more advanced builders, perhaps adding in vacuum stuff and welded pipes, control units as optional extras. For simpler units would just covering the trough with toughend glass or pvc work as well as a vacuum tube? Ross

[@ancelgray]

Ross, I have considered putting out plans for different levels of users. However, I still have not completely finished my own project. I just made a REAL etched circuit board for the control electronics (replacing the prototype), and it is now working fine. It has an Altera CPLD on it replacing all the logic (shew wheee!). I still need to mount the array on top of my roof! Covering the trough with glass would be great. I could not find an economical way to do that though. My troughs are 5 feet long, and I could not find appropriate glass tubes. Also, I was experimenting so much that it was better for me to have an indestructible polycarbonate covering tube (as I was taking them apart and putting them back together multiple times). Perhaps on Round-2 I would use glass. I do not think PVC is transparent enough in the IR and UV frequencies to make it worthwhile, and I am not sure how temperature stable it is. George Plhak has videos and plans that you can get started with (that's how I got started). He can be found here: kzbin.info/www/bejne/bHiQmZdpgp6sisk Search for "George Plhak" on KZbin to find a plethora of more info. He also has a e-book that you can download (I have it). Andrew Ancel Gray

[@SamWhisper1]

would you consider building a system to sell?

[@ancelgray]

Yes, perhaps. However, I have SO MANY THINGS on my bucket list. Getting this system to economy-of-scale so it can be mass distributed is a huge undertaking. I am basically a green slacker and not a capitalist "bidnessman". Is there someone out there who you know who would like to do this? I would be willing to help by donating the technology.

[@ancelgray]

From Daniel: Hi Ancel, I've been most impressed with the videos you have produced over time. Could you list the electronic circuit boards, programming and other details that run your Solar heating system please? Daniel, here is the circuit board I made to run the Parabolic Water Heater: modelofreality.org/SolarCircuitBoard.jpg This board piggybacks onto a PC Engines Alix 1E (or 1D or 1C): siliconkit.com/ocart/index.php?route=product/product&product_id=104 All the software fits on a 4 GB read-only compact flash. The OS is FreeBSD (the same OS as Apple's OS, very reliable!), and the controller is written in C (written on top of Linphone as a base program so the controller can call/text you if there is a problem!). There are four, 4 amp, DC motor drivers to run the DC motors and a pump (plus an optional backup pump driver).

[@ancelgray]

+ancelgray From Daniel: Hi Ancel, Thank you so much for your time in replying. I am more mechanical than electrical. Would you be willing to put together the same package as you have; less the motors, due to weight and postage, if l were to send you a fee please?

[@ancelgray]

+ancelgray +Daniel Phipps So you are looking for the electronics boards and the boot-OS/software Compact Flash card(?) (Do you want to purchase the Alix-1E, thermistors, motors, &power-supply online?)

[@ancelgray]

Daniel, read this user manual and see if everything looks good: modelofreality.org/FocusTheSunUserManual.pdf Also, see message below.

[@ancelgray]

+ancelgray Ok, see other message.

[@ancelgray]

Daniel Phipps Ancel, Is this all your work? Its an amazing piece of work. Congratulations. I am not only impressed by its complexity but the way it is written and how it explains things. What does the package cost? I can purchase the motors and thermistors here once l have the specs.