DIY Solar Generator
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- Опубликовано: 5 фев 2025
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The Sun sends enough energy to Earth every day to power the entire planet for thousands of years. How can we harness that effectively? In this video, I take on the challenge of building a giant modular, sun-tracking, parabolic solar mirror inspired by NASA's billion-dollar James Webb Telescope design.
Engineer here with a few suggestions -
Your aluminum plate should have been copper for a couple of reasons - first, aluminum is reflective in the visible spectrum. A copper plate can be treated with a liquid known as "liver of sulfur" which creates a strongly-absorbing black surface, dramatically increasing the amount of energy that can actually be absorbed. Second, copper has a thermal conductivity roughly twice that of aluminum, meaning your total thermal resistance is lower. The net effect is that significantly more heat can flow from the absorbing surface into the water.
Another consideration - choose the flow of the water carefully so that you are in the turbulent regime - this will increase your Nusselt number and further improve your efficiency.
As others have also pointed out, each mirror segment can be flat as you are trying to focus onto a large area. This is also preferable as a uniform temperature distribution in your collector will also serve to boost your efficiency. I suggest you look into non-imaging optics, and specifically into something called a compound parabolic concentrator or CPC.
Another more advanced improvement that can be made is to place the front side of your collector under vacuum, or at least under partial vacuum. This reduces convective losses from your collector.
You may also find after having made these improvements that there will exist an ideal operating point where you have the collector operating at a sufficiently-low temperature so as to reduce radiative losses. The blackbody radiative losses from your collector scale as temperature to the 4th power, so while faster water flow will help you get into the turbulent regime it will also lower your operating temperature which serves to reduce radiative losses.
This is a cool project with a lot of room for exploration! keep up the good work!
turbulent is less conductive
@@Blox117 It is more convective than laminar flow.
@@Blox117 you have a brain. Use it to be positive and not cynical and maybe you'll realize that you're smart.
Regurgitating what you think you know rather than taking your time to figure out why you're not understanding is a trait of a very low class citizen
Blackening the collector plate is a great idea. So is cutting narrower or shallower channels to give the water more surface area for heat exchange. For proof of concept, imperfect mirrors shouldn't make a huge efficiency difference, since they're concentrating the light anyway. Choosing less transmissive film might though.
would also suggest to make the plate in the middle black, but still leave it be in aluminium since a copper block that size would be way to expensive for a project like that, at least for now.
Gold paint ≠ gold reflectivity
Silver paint ≠ silver reflectivity
At least outside of the visible spectrum. Paint just looks the part -it's optical properties are totally different to precious metals and also different to whatever coating is on your plastic mirrors.
Yep. In general, even with the reflective film, that will usually still have plastic surrounding the colored pigments or film layer.
Either stuff is suface-coated with a metal film or not. So electroplating, true chrome either without a coat or with an IR transparent coating and sputtering are probably the most common ways to get this done.
But it doesn't really make sense to use semi-gloss chrome paints or these films where the properties are unknown for these comparisons :/
I was thinking the same thing.
This was really strange to watch.
Golds chemical properties allow it to be polished to such a fine degree, that it can refract the wavelength of infrared light. The color itself doesn't matter.
@@hondacivc93 Why talk about things you know nothing about?
1. It is not polished, it is deposited on a previously polished surface. The same way any other first surface mirror with silver is made.
2. Pretty much anything can be polished, as that is only a measure of surface roughness. There is nothing inherently preventing a perfectly flat surface.
3. Flatness has nothing to do with how good this flat surface reflects a specific wavelength. That is inherently a property of the material. You can polish coal as much as you want, it will always be black. Gold is always gold colored, no matter how rough you make the surface.
4. The color is said inherent material property and is all that matters for what is reflected. The flat surface just makes sure that the reflection ends up where you want it to, instead of going somewhere else. That is all the flatness is needed for.
Apply the reflective film after shaping the plastic....
Hard to apply flat sheet cleanly to a curved surface without creasing
@@taureviews if it's reflective tint, use a heat gun and soapy water, I promise it works.
Dido
@@taureviews People do it every day wrapping cars.
Its not you are wrong @taureviews
One glaring thing that may be a problem... the heat collector is currently reflective. Spray it matt black with heat resistant (stove paint) paint as it will absorb heat much better than the shiny surface.
Good one!👌
@@ConceptCraftedCreations dimple the surface like a golf ball before you paint it for more surface area.
@@ConceptCraftedCreationsThe fact you're using aluminum gives you an option for making it black:
There was research done stating that a simple candle's soot actually forms carbon nanotubes onto the aluminium surface.
Simply put, just soot the aluminium disc with a candle and gently have something transparent to protect it from the elements.
Used this for my solar space heater, works well, however haven't tested if simply painting it black has any difference. But theoretically the nanotubes would be perfect light capturers.
@@ConceptCraftedCreations it might be hard to find paint that can resist such high temps, but i hope you do. In either case sand down the surface with a medium grit to make sure there is no reflectiveness, either on the black paint or the bare aluminum.
@@IvanSpaceBiker that would do absolutely nothing.
Since you're trying to catch the light on the big plate, the parabolic shape on your primary mirrors is unnecessary. Each petal or mirror segment can be flat and the secondary mirror can be flat; the parabolic effect will come from how each segment is focused on the secondary. Rather than throw a tiny hot spot onto the receiver, let it be bigger and heat the whole thing more-or-less evenly. Lower deltas are less lossy.
Also: you really want a dark receiver. Shiny silver will reflect a lot of the incident energy, shiny black will absorb it without re-radiating it so readily. Your ideal surface should be black chrome.
If he wants to achieve a real focus, each mirror should be a section of a paraboloid. Mirrors at the same radius can have the same shape, but the mirrors should be different shapes at different radius values.
I did something like this with a 1.2m satellite dish and aluminium foil, and then a mylar sheet over the dish and partially evacuated the volume behind - it was scary efficient!
I used candle soot to coat the bottom of a pan to absorb the energy.
At night, I could point it to a clear sky and use it to freeze things!
Yeah! The aluminum plate needs to be as black as possible. And not gloss black. Matte black
Agreed. Given that each mirror is similar (or smaller) than the collector-plate, there's no need to concentrate the sunlight, simply reflecting it with a pile of small individually flat mirrors will be sufficient. So he spent a LOT of time and effort doing something of no practical value here.
If you want to concentrate the light back to the back you need a Ritchey Chretien formula so hyperboloid mirrors on the primary mirror and a correspondant hyperboloid secondary mirror. But it's complicated and overkill.
I would have use paraboloid mirrors on the primary but would have place the heat plate on the focal point instead of a secondary mirror. It makes the formula way easier to colimate and you get rid of difficult to build optics.
As others mention, darkening the hot plate ensure light coming from the primary mirror isn't reflected so lost.
The heated aluminium disc should be dark, black (but not catch fire) to use enough of the light that is focused on it (as it's well known, the darker the object, the better it heats up).
And, I'm sure you've considered this, but just in case: of course each segment must be the shape of the corresponding part of a parabola, not of the parabola's centre.
If the focus point will be few centimetres above aluminium disk, trap for light could be made: second disk with small hole that will be few centimetres above main disk and aluminium wall between two disks. that way almost all light will get through the hole in the first disk and then rereflect many times inside our trap, heating everything up. This also will stop wind from cooling main disk. And of course all walls inside trap should be black - main disk heat resistant paint and other walls of the trap could be painted with black 3.0 to really boost performance.
@@MrMpakobec Поддерживаю
Not necessarily, if all parabolic mirrors (and their respective focal points) are equidistant to the secondary mirror/heater plate. It's way cheaper and faster to have one mold for all mirrors.
3d Printing 6 different forms (as it's rotationally symmetrical, you should be able to reuse them) probbably isn't too much overhead, but I'm not certain it's worth it. In case of remoulding, a vacuum attatched to the negative mold might pull the plates into shape without damaging the mirrors finish by compressing them from the top.
A more expensive option might be to get copper-clad plexiglass for the panels, form them and then electroplate them silver. The upside is you should be able to get a very eaven coat by placing the opposite electrode at the focal point of the mirror, so it's fairly equidistant from all points (minus the spherical/parabolic deviation) That would hopefully remove some of the waviness you have in your formed sections from the adhesive releasing and/or the film buckling.
Also needless to say, make sure if you paint the plate black, you use temeperature-resistant paint like the stuff the make to paint mufflers or barbecues. Probably need some sort of primer with it as well, although the more different layers you have the worse the thermal conductivity could possibly be.
Building all of this just to be hit with the reality that you live in the Netherlands is very relatable. It's like when me and me dad installed solar panel lights on our house and forgot we get an absurd amount of clouds, so we originally thought we bought defective lights XD
Send me a version for testing in SEA. I already have a neighbor with a similar set up who sells solar roasted chicken on the highway. I will send back a cut of the profits for further R&D.
Do you remember if they were the blue crystalline looking ones or the black ones with stripes? The blue ones have like 4 times the Amp output in relation to surface area but only in direct sunlight. The black ones will output under 4 inches of snow and clouds.
You need an optimisation for diffuse Licht ut would help
i think it was 2004 the CSIRO in Australia built a large molten/solid salt solar reflector system that reached higher turbine steam temperature than has ever been achieved in a fossil fuel turbine. California put up a system around the same time but little has been done with it considering its potential to generate power for hrs after the sun is off reflectors thanks to molten salts high thermal capacity
as for panel systems there's a NUMBER of factors that influence the sun levels needed for power the more line impedance/material to length to diameter to amps the less efficient the cable panel interface and panel cell interface the more resistance in inverter and battery's the less of the 22-24% (average panels ppl use these days efficiency) we manage to capture actually makes it to the destination
reflector systems actualy do away with a lot of resistance because your heating a central rod that then boils and turns a steam turbine like a regular coal or gas plant and even in low light u just need a larger mirror footprint and u can get same heat
but on a regular PV you can be getting double or triple the power depending on those factors from a system that is technically the same if your just looking at panels rated output tested at a cell level
yep this is why my new design for a multiple power source green power system will provide for 24/7 365 power production with a scalable design that can be produced for both commercial General grid distribution to a private at point of use (no grid tie in needed, thus reducing demands on a frail public utility system) Also providing a system deigned for very remote points of use. This system's use of several proven green power technologies provides a level of reliability in proper power production that few if any other green power systems can provide ( excluding systems that are anything but naturally occurring that use exotic elements & or fuel sources. { I.E. atomic, oil gas, coal } All of which can cause very harmful byproducts & waist. NONE OF WHICH ARE TRULY NEEDED to obtain large volumes of energy. ) I have the design but do not work for free.
JWST needs parabolic mirrors to create an image, you do not have the same requirement: you just need all the light from a mirror to reflect on the collector. A plane mirror illuminated by the sun creates a reflection of the same size at most, so the only requirement is to have a collector of the same size of the mirror.
This is a good point, I think a solid compromise that would be especially effective here, is set a reasonable focal goal for the curvatures, small enough to splash the majority of the target for good transfer.
Partially true, but one thing to consider is that the efficiency of a solar heat collector is proportional to the temperature difference you can achieve, and you can get a larger temperature difference for the same size collector by concentrating the light using parabolic mirrors.
Yes, focusing to a point is unnecessary unless you want to melt things - key is to collect energy as heat more efficiently, not concentrate it more than is necessary.
The same energy can make a high temperature over a small area, or lower temperature over a larger area, and the latter may be more efficient by maximising heat transfer time to heat the fluid medium by the desired amount. There are a lot of things to consider.
Coating the collector with soot from a candle will also increase absorption.
I agree, I think for a V1 flat mirrors are fine. Parabolic mirrors should be an improvement as an upgrade for more efficiency.
@ No, flat mirrors only fine if the collector is where all the reflections impinge on it on the end of the boom.
There is no shape that can then reflect them all to the collector in the centre of the dish as they would all miss except one.
In this case they would need to be partially focused to land on a parabolic convex reflector to then land on the collector in the dish, with a suitable radius to provide a temperature enough to heat the water to the desired temperature.
Color isn't really a good indicator for reflectance of infrared light. Actual gold like the stuff used on the telescope would reflect much more light, because the spray paint uses stuff that looks like gold, but isn't, it probably reflects much less light.
Lasers (IR CO2) use gold mirrors, they work well enough up to about 50W. The coating is rather fragile. They're reasonably cheap but small, only 20mm.
Telescope dudes will sputter silver onto glass (say 300mm) easily enough, could probably point you towards someone who could do gold. These would have the coating on the front.
@@j.f.christ8421the silver would be oxidized very fast in the heat. In this case aluminum is probably best
@@ralanham76 Yeah, good point. Aluminium might even be better, it performs only slightly worse in visible (5-10%) but reflects more IR than silver.
EU TENTARIA ESPELHO FLEXIVEL A SER COLADO NO FINAL COM TODOS EM SUAS POSIÇÕES;DISCO DEVERIA SER NO PONTO FOCAL E NÃO NO CENTRO DO REFLETOR.
It would be polite to begin your comment with "Great vid" or "Cool project"
But I know politeness is not a thing in some cultures
Very good project.
1. Place the heat receiver on the rods, and not reflect the light twice, which only leads to double losses due to light reflection.
2. Paint it black or smoke it with soot. 3. It is possible to apply a reflective coating after forming the bend of the mirror, in order to avoid cracks when heated.
4. Add a protective layer on top of the reflective one, since it is difficult to maintain the integrity of the coating in the sun, wind and rain. Plus, the second layer can be polished with a car polishing machine.
5. Replace tracking by lighting level with a simple table of the sun's location by time of day (but then you need to add potentiometers or decoders to the rotary axes).
6. If you want to leave the installation outside for a long time, you need to add a protective function to avoid strong winds, add a wind sensor or simply take information from the local weather forecast (mirrors are just a big sail)
I agree with all but #5
Won’t that table shift by time of year, requiring either manual adjustment or additional complexity?
I personally think this method of tracking is super elegant and quite simple overall.
Sun tracking can easily be done with integration in Home Assistant. There already are automations doing this to control blinds. It adds complexity though. The LDR/Arduino system is simple, robust and cheap.
I have to agreed with @RobertBruce, but I would also put particular emphasis on points 1 and 6.
No reason to have the collector at the back (especially since there didn’t appear to be any significant reflector at the end of the arms). Put the collector at the end of the arms and have it capture all the heat being focused by the mirrors.
Finally, if you’re going to keep it outside for any length of time, you should strengthen the vertical tracking portion of your system (at a minimum) otherwise the first stiff breeze will likely cause a catastrophic failure.
Hope some of that helps! Looks like an awesome project!
The mirrors away from the center have to continue the parabola, aka, you CAN'T use the same mold for all of the mirrors, the light will be coming at an angle and not go to the focal point, you need 3 different molds for the ones nearest to furthest from the center (also molds will be directional)
Also do note, if you want to focus all light onto a single point the secondary mirror will have to be an ellipsoid one, with one focal point matching the one of the large mirrors, if you want the heat to be more evenly distributed a parabolic mirror will do the trick
@darioferretti3758 Being a technical person myself, I understand the tendency to over-engineer things to astronomically mathematical precision. Nature is usually more forgiving. The goal here is to concentrate sunlight on a collector that is a disc, not a point. Overthinking can improve efficiency marginally, but that kind of precision just isn't necessary. Especially for a proof of concept. Close is good enough.
Instead of allowing the water to flow through the collection plate under acrylic, I would of put copper tubing and soldered it into place to make better contact. Better contact allows for more efficient transfer of thermal energy. Also, the water will get very hot and start to build up pressure which can cause the acrylic to start to flex under the pressure, plus the heat making it softer.
On my single solar thermal collector I had on a 2ftx4ft panel, the water would start boiling before exiting the system, which led to a lot of a air locking keeping the water from flowing smoothly. The system *had* to run under pressure to keep the water from boiling so easily.
Yeah, that acrylic backplate is just begging for leaks. The mirror tests already show it can significantly flex at 100C, and there's going to be a lot of water/steam pressure in there.
I suggested in another comment that a car radiator would be a better collector.
I'm also wondering if freezing will be a problem. Overnight there is gonna be a bit chilly
As someone who builds solar cookers I've never seen anyone at that level of engineering (except industrial projects). Very impressive and I also like the design👍Looking forward to part 2
Nah, he overcomplicates it. Keep it simple, that's the recipe of a good solar cooker :D
@@Sekir80 I agree, but it's always nice to see a different approach.
I like to see builds like this more often. Not only does it look sick it's also functional. I know people are saying about how it could be improved but I think it is fine how it is!!
Great project! Some thoughts:
1. Probably the best, cheapest mirrors you can find are the aluminium discs in mechanical hard drives, which are regularly used as front-surface mirrors for laser builds. Sure, that means a *LOT* more mounting points, but the better efficiency should make it worthwhile. For mounting, you could cut some discs into washers, which will reduce mounting to a single screw. Also, as aluminium is fairly soft they should be easy to form into a parabolic shape.
2. As the amount of screw adjustment needed for focusing each mirror will be relatively small, slices of PVC pipe would be sturdy enough and provide enough spring while being _dirt_ cheap. Alternatively, as you should only need to worry about tilting towards/away from the center, you could 3d print a mount with built-in compliant joint and just use a screwed wedge to set the angle. That would make printing and assembly *MUCH* faster and easier.
3. Rather than depending solely on light to determine where the sun is, just use one of the many Arduino solar tracking libraries to ballpark the position using lat/long/time/date. It can not only always aim your mirrors directly at the sun, but can automatically reset the array for morning. You'll need an IMU to feed back the array's direction and inclination, as well as an RTC, but those are cheap and easy to incorporate.
4. That vertical mount is... sketchy, at best. I would pivot the array around its center of gravity in the center of the platform, then tilt it using a tight non-elastic cord/belt/chain that is anchored to the top and bottom edges of the array and travels around a gear in the middle if using toothed belt or chain or wrapped around a powered drum in the middle if not.
Cheers!
Awesome 👍 I'm doing an experiment with lunar simulant, sintering sublmation, and deposition. One of the ideas is to use a solar furnace on the moon exploiting the vacuum environment to create eutectic alloys. Excellent video 👍
slewing bearing ok, but springs expensive?
xD
(I'm not American) My salary is less than $100 a month, however I recently allowed myself a set of 200 springs for $5 for the sake of 4 springs :)
But the springs can really be replaced with alternatives, and the bearing is specific and very important, I guess it's just the man was choosing what to spend money on and what is not worth it
@@broniusale5987 Yeah, I don't understand what that was about either. Just looked at temu, searched for springs: springs galore for 10 to 20 ct a piece.
@@MartinMaat don't promote cancer temu. it's a bloatware to the economics and healthy market.
You can probably buy springs by weight, 200g should be enough
That's what I thought! Surely TPU is much more expensive than steel springs?
Maybe consider painting the collector plate black?
Yeah, I thought there was no way you could finish the whole project in only a 13 and a half minute video. Well, you are almost done. Can't wait for part two!
Glad you enjoyed it! Part 2 coming soon🤓
This is one of the best technical videos I watched on RUclips !
I was impressed by the idea of shaping the plexiglass to the parabolic shape.
I myself once tried to make a parabolic antenna with plastic materials but wasn't smart enough.
Subscribed !
1. like others mentioned, center disc should be black, 2. like others mentioned the individual mirrors can be flat, 3. I'm fairly certain if you have high winds, 40+ you are going to find your whole device slammed to the ground. 4. your concept is great and covers all the needed points. but it's not ready for high winds. 5. pretty sure those tpu springs, cool idea, will eventually collapse much sooner then steel springs. look at buying the right springs in bulk prices. 6. I like that you reminded people that only 4 sensors are really needed for sun tracking. but for those looking for a non arduino way of doing the same thing, look into using those same light sensors (variable resistors) to control the motor, it will require some old school electronic knowledge.
Thanks!
Wow, I love the way you cover major engineering challenges and even your design mistakes and why they failed and how they possibly could have been avoided. So many good lessons on the process of design and the use of hobbyist tools to achieve complex designs. I am an instant fan. Can't wait for part 2.
Every other cut a new piece is printed or a new graphic designed. It is absolutly incredible how much time you spend on this project and its documentation while making it look like a walk in the park right here.
6:58 missed opportunity to give a gold medal to silver and a silver medal to gold.
Move the heat plate to the position of the secondary mirror. Every reflection costs energy.
Great Idea! For the Parabolic Curve. . . You could just Keep the Mirrors Flat Since they already Follow a parabolic curve. Otherwise Each Mirror would have to Have the Individual Corresponding Curve for that Segment of the Overall Parabola of the Dish. Without that Exact Arrangement you will loose Light Density, I personally believe Flat Mirrors Arranged along the Parabolic Curve would Give an Overall Higher Density of Reflected Light though not 100 percent.
That's what I was thinking. I'm sure there are quite a few scientific journals on what's best. there's no need to reinvent the wheel with how much effort is being put into it.
the focus points would be too big but yes its easier to do.
This is what RUclips was made for, clever inventive people of intelligence and good intentions. Really love this mate looking forward to watching more.
One idea I have is to use a large mirror array to shine light onto areas that are in constant shadow to improve the quality of light and provide some heat for people who don’t get much sunlight. The only problem is I need a large mirror that wouldn’t be practical. But I took a small bathroom mirror and reflected it onto a wall and you could feel the temperature increase as I walked through the reflected light.
Really interesting project. My thoughts. Gold paint and gold are obviously different but that’s not important as cost is a factor. You could try using aluminium foil or even “speed tape” (aluminium tape). I don’t think using parabolic mirrors is important if the overall shape is parabolic. You’re just trying to focus the light onto the central mirror and then onto the heat collector. The central mirror may need to be parabolic to focus the energy roughly onto the collector.
Why not just stick small mirrors onto a TV dish and try that. Much cheaper especially if you get a scrap one. The dish and mounts are also designed to work in high winds but the weight will mean larger motors and you may need to use a counterbalance to help lessen the load on any motors.
I'm guessing the JWST used a gold coating because it is good at reflecting IR, because imagining in the IR spectrum is what the JWST's main mission is.
apart from the hinge that should be in the center of gravity (because your country is so windy and that thing is a huge wind catcher) while the motor pivot screw is well placed to have less work. Your entire project looks very pretty and stylish!
I like the mirror segmented, easy to replace if any damaged, allowed fine tuning, and cheap compared to a giant curved mirror. Nicely done
The one thing that jumped out at me was your use of orange plastics. Years ago, I was told that for some reason (ones I don't remember), orange does not hold up well when exposed to UV lights. I've since seen ski boots, garden equipment and buckets made with orange plastics. Thinking the issue had probably been resolved...I found out the hard way. Buckets and garden tools that I've had outside, broke down very quickly, compared to others. Other than that small concern, Cool video!
If the mirror puts a large strain on the tilt motor, could you add a counterweight to balance it?
Theoretically that would be possible yeah!👌
great comment! all gimbals are balanced.
The centre collector needs to be painted matt black for greatest optical absorption and heat transfer. Otherwise, an awesome project!
test the springs at different temps, cause they might lose their strength when hot from the mirrors
Actually the back of the mirrors will be cool as their purposes is to reflect
I think, its a good idea and solution for the heating problem. But I guess you will have a stability problem with the wind. And by the way, when the milled plate in the middle is colored in black, it might absorb more heat from the sun. The price for the milled plate is average. I work for a tool building company in germany and the price, I can made this plate, is nearly the same. The biggest question is the aluminium itself. The plexy glas backside is perhaps a problem. The cooling will eventuell fail , when the alu plate becomes to hot. I love the way you show you're errors and the improvements. Good job !
What is the energy loss of having a 2 mirror system vs having the alumnium plate take the direct reflection of the first mirrors?
More complicated piping I assume
@@p529. same piping. just put the plate into the focus point and its done.
@@jpjay1584 I'm assuming it's more about the weight of the heat plate versus a mirror than anything else.
Yeah, the ‘heat plate’ really should be at the focal point of the mirror array, instead of a double mirror.
The weight of the heating plate might be the main reason for the design choices here.
For the sun tracking I'd seriously consider an equatorial aligned single axis drive, just like a German Equatorial telescope mount, it will allow for counter weight balancing to lessen strain on motors. There's a market for second hand mounts with some sophisticated tracking software more than capable of following the sun even over multiple days.
You don't need your primary reflector segments to be curved either, they can be flat as you are not trying to cast the image of the sun on a focal plane, you just need the maximum of light from each reflector to reach a common surface area which will be your collector. If you could position your collector in front of the reflectors instead of needing a secondary reflector to send the light back down again then you avoid losing energy to a second reflector which will itself also be getting quite hot as it is nor reflecting 100% of the light/heat.
Dude. this is pretty cool. I'm almost 50 and I never knew the difference between parabolic and sphere mirror. Thank you for that! Oh... and those printed springs are awesome!!
Basically make this but have it boil water by focusing the panels onto a single glass bottle and then have the steam run out of the glass bottle in a closed loop that runs a turbine cools condenses and is then pumped back to the glass bottle. You can have a short program code that tells it to point at the brightest object.
I would put the collector at the 1st focus and make it a sphere with a hole in the side to let the light in and stop any reflections from leaving.
Imagine machining channels into a hollow sphere with a hole in the side, then coat the inside with candle soot.
This way, you won't have to worry about machining a secondary mirror. The parabolic segments reflect just once through the hole in the sphere and everything is captured.
I made a solar tracker using an Arduino, GPS module and two servos, (later two steppers) and some code to translate time of day and lat/long location into elevation and azimuth in degrees.
Works even when overcast. Add an anemometer then set to elevation to 90° if wind exceeds a limit.
Use a linear actuator for elevation - this can take a lot of load. Raise the dish and add a counterweight to reduce static torque.
Servos are a pain - they want to slew suddenly to another position at power-on, and that can break things if they don't have a clutch mechanism!
The light absorbing element should be insulated, for instance in a vacuum, so as not to lose thermal energy.
Insulate sides not facing the sun. Use greenhouse effect to let light into but not escape. The black absorber can be inside the water.
Amazing project, choosing foil on Plexiglas with foil as reflectors....well its cost effective.
The bigger problem i see is with using Plexiglas as the back cover for the heat collector.
Years ago i tryed to build watercooling blocks from Plexiglas and found out it gets very soft around 60C already, making the seals leak because the skews loose pressure cuz they sink into the plexi.
Winter in the Netherlands seems like an awesome test of minimum capabilities. You can't always count on sunshine on a cloudy day, so prepare for the worst, and hope for a surprise!
Your tracking system looks good and it's probably easy to do it digitally but it could actually all be done with a few op amps. One thing though about the heat collection. Your plate should be black to absorb as much heat as possible using black chrome or black nickel. And it should be a very heat conductive metal such as copper as well. Those tubes should be copper to transfer as much heat as possible. I even considered iron but that's not as good a heat conductor as copper or aluminum. I think it would be funny to grab an old iron frying pan (your plate looks about that size) and cut off the handle and braze the copper tubing to that. Solder might actually melt if your machine works. I've seen much smaller solar cookers and they get amazingly hot. A recessed collector or a semi-spherical collector is more efficient because it traps light and minimizes heat loss. Ask Chat GPT about this. I did and it gave me a lot more than I put here. Everything about this is subject to cost and ability to actually do it. I think since you already have an nice aluminum plate you should just keep that and coat it black and replace the tubing with copper. One thing that popped into my head is, how do you make aluminum black? Then it occurred to me that all you need is a cantle to coat it with soot. That's plenty black. Or paint it with black stove or BBQ paint.
Love the idea! But as a blond tinkerer there is a couple things i'm not sure I get.. 1. Do i get it right, that there is mirrors, mirroring to a mirror that mirrors to the heat plate? So the output is warm water, after all this reflection? Would the temperature then be used in some heating pump setup to catch the energy, or just for hot showers? 2) if the mirror is taped on anyhow, could it maybe be put on one large old tv parabol (junkyards), that would have one common focuspoint? Thinking many smaller ones should maybe not be individually parabolic, but as "slices" of the whole (i.e. At least every cocentric circle of smaller discs should have different angles) as i guess it would be the centre bulls eye that is pointed at the strongest light?
Some suggestions: Rather than try and bend the mirrors into shape, you could try Mylar and a vacuum to form a perfect parabola and focal point - no screws or heavy mirrors required. You could also make the mirrors a LOT larger. Mylar only reflects about 90% of light but making them larger (maybe to to the same weight) you''ll get a lot more overall energy.
I presume the secondary mirror you mentioned (not shown) will be at the focal point and it's to reflect the light back to the heat exchanger. But that secondary mirror will need to handle about 7kw of energy - the same amount as the heat exchanger - it's going to get very hot, very quickly. A single reflector (array of articulated mirrors) will be easier to build and won't melt.
So if you created an array of vacuum drum mylar mirrors each with 2 axis articulation and an adjustable vacuum - with some programming to relocate the focal point you will have a death ray.
mylar on it's own is already more reflective than the mirror tint he's using, so this is a good suggestion.
I'm a smart guy. I love building things.
I watch videos like this and think 'damn, I'm either actually dumb or just get bored far too easily.'
I *understand* everything he did but I'd never have the follow through to put all this together.
Kudos.
Ok.. 4 minutes in.. I just want to take a minute to compliment how hard core bad ass this is. I mean wow… just wow. So killer. You’re just skimming past the 3D modeling and printing for the right alignments and all that. Incredible work good sir.
Using windows tint should allow you to apply it to the curved acrylic AFTER shaping.
There is a technique using heat guns that tint shops use to shape the film to curved surfaces.
I believe this would allow for a cleaner/smoother surface finish, thereby a more efficient system.
Because he uses heat to shape his mirror segments, then using heat to apply the mirror film might change the shape of the mirror segments.
Though, I'm of the opinion like other people that he really doesn't need to focus each individual mirror segment since his collection plate is nearly the same size as the mirror segments. He isn't trying to capture an image of the sun, just collect the light.
At least you're trying, I'm glad the rest of the world are trying to help you!
Paint the heat collector black, as silver reflects...no need for individual curved mirrors, as the current setup uses low reflectivity film. Rather user real flat mirrors and get all reflections from the flat mirrors to overlap on the heat collector. More smaller real mirrors may be the way to go.
This video is a great example of the difference between "making/crafting" and "engineering". Lot of fundamental errors; though the mechanical/kinetic aspects are pretty well thought out. Too many people gave out a lot of useful information , so i will leave it at that.
The only thing I would have done differently is just make one huge parabolic instead of segmented ones. I also would like to see how it's going to be used because I'm having trouble understanding how other than just heating water what use is it? granted heating water is pretty useful too.
Humanities scientific advancement is pretty much measured by how complicated a way we can devise to boil water.
home made solar water heater powered by a fresnel lense
ruclips.net/video/rrGMidc_P7s/видео.html
One huge mirror is more difficult to make. That's why the Webb uses that hexagons. Of course, individual mirror segments have their own issues....
Easier to replace a single failed mirror from an array, rather than having to replace the whole thing.
Also easier to make small mirrors than big ones
Also easier to correct for flaws etc with small mirrors than one big one.
There are some advantages to a solid mirror. There are some advantages to a mirror array. 🤷♂️
If you point it at a solar panel you can get a lot of power out of it. Most aren't rated for that level of power though so for consumers a heat based generator might be more plausible
For the stability of the array, perhaps a light compression shock absorber on the top side of the array to assist and stabalize the threaded rod erector.
That's so cool. I think that the segments should be offset paraboloids. Also i wonder what geometry does the secondary mirror has
This is a cassegrain antenna design. The formulas are all over the antenna design websites. It is very critical though. and actually you usually want to focus in a single point but for this you should try for a focal point past the plate just where the cone of light would evenly cover the plate.
Try using axiconal mirrors, much easier to make. Me and my 12 year old daughter made a Cassegrain solar concentrator/cooker 25 years ago using axicons. A primary 16" across was sufficient to cook things like hamburger patties etc.
I think you should create a solar tracker that only requires grid coordinates and a calendar to operate. With those two pieces of information, one should be able to create a platform for solar collectors that is 100% accurate without worrying about it being exposed to the sun.
for me it would be more of a hassle because you would have to code for it. his solution is pretty straight forward easy
That probably wouldnt account for cloud cover very well
@@GabrielRowanonRUclipsAn advantage of a system like I described is that it wouldn't need sunlight at all. It would face ideally regardless.
@@1chumley1 I guess that depends whether ideal = pointing at the sun, or if it's whatever the brightest part of the sky currently is. For a place that is often cloudy it may not be the sun
Though in any case I do think making it point at the sun at all times would be cool
@@Incommensurabilitiesyou really only get power out of solar panels when they are pointed at the sun. You won't get anything out of them if it's partly cloudy and you point them in the brightest direction, the light bouncing around is all incoherent, and nowhere near bright enough.
Solar panel efficiency also drops off RAPIDLY even on cloudless bright sunny days when you don't have your panels angled directly at the sun.
Tip. Have a look at a polar aligned equatorial wedge.
You will find tracking easier as all the tracking for the day can be done with one motor running at 1/24 revolution per hour.(the earth is rotating not the sun moving)
Why is the disk in the middle silver it will reflect heat & light, it should be the darkest matt black you could find.
Did you apply the paint at the front of the acrylic panes? It wasn't clear to me, it would be best to apply it at the back like with any mirror. Then the aluminium core plate must be painted matte black of course, you do not want that to act as a mirror too. I expect some issues with boiling, tubes may burst or come off. You may need to control the water flow based on the plate's temperature, making sure it won't exceed 90 degrees Celcius or so. And using astronomical data tables for your date and location seems more effective than trying to figure out where the sun is in real time. This is how all trackers for solar panels work. Overall I am impressed once again.
Yeah, he's going to need a lot of water pumping through that block to keep the sink below boiling temperature, which means needing a constant use for the hot water. Recycling got water will also make it boil.
Honeslty, being able to form the plexiglass mirrors at 100C means getting any where close to boiling will cause the seals around the plexiglass backplate to pop. The tempreature and constant water/steam pressure will warp it.
A common mirrors is backed to use the main clear material(glass) as a means to protect the thin coating that produces the mirror finish. Typical acrylic mirrors(makeup mirrors and the like) put the mirrored surface a the front to prevent double images. I ideally the lenses should be coated in metal foil as paint looks like metal but it doesn’t have the same properties.
When using a mirrored backing the acrylic will absorb some energy reducing efficiency of the mirror and generating unwanted heat. Given the mirror is acrylic that additional heat would likely deform the shape of the mirror. Putting the mirror on the outside will reflect more of the incoming light and reduce the temperature of the acrylic.
@@jacobs8718 That's nonsense, we're dealing with direct sunlight, not lasers or already concentrated "high energy" light beams.
@@MartinMaat I rewrote my response. I reread it and I disliked the tone and content so I changed the direction of my response to promote better discourse.
btw, I said “high energy” not in a technical but relative sense. The suns 1000 w/m² load is not insignificant to a design that uses sheet acrylic. Typical use case for an acrylic mirrors is indoors and notably less than 100w/m².
@jacobs8718 I still don't see how direct sunlight is going to heat up an acrylic pane. Do you have a source for that? The stuff is used all over the place as cheap double glazing, mounted on window frames, facing the sun. It does absolutely nothing. We had one such pane at home when I was young to save energy. I just looked it up, it only gets somewhat soft over 85 degrees Celcius. It never significantly goes over room temperature. Granted, with a back coated mirror light passes twice but so what? It is a clear material. Even if it would absorb some frequencies, those would already be absorbed on the way in and thus will not be absorbed again on the way out.
I have a similar idea, except with a parabolic bubble that would focus the sun to a black graphite element in the focus region no matter where the sun was passing over. Obviously the lense bubble idea is prohibitively expensive.
there is spray paint that makes a mirror, better than the film.
Rust-Oleum Mirror Effect Finish Spray
Tracking solar panels that use a system like this one will be almost constantly tracking, and the heavier they get, the more motor power you need. On the other hand, humanity has been predicting the position of things in the heavens since before words like "science" and "astronomy" even existed. Simply find out where the sun will be in the sky where you are that month, and have the panel adjust every 15 minutes or so. Not quite as efficient, but you'll probably get to "keep" a lot more energy.
Easier solution: widen the photoresistor assembly and use a bigger sun blocker. More shade time would produce fewer movements. Simple, low-tech solution.
Solar clocks. Surprisingly the movement of the sun seems to coincident with a 360 degree rotation. So basically horiz rotation could be done without frequent measurement, to avoid "cloud effect". Have the ardu rotate on some deq/time interval that seems most efficient &power down, maybe a position check once or twice a day, and possibly add a latch, if you want to avoid stress on the stepper holding torque/mechanism (storm stuff). Vertical either in interval measures/movement, or even catching daily top position, average, some math, and base movement on that. Again to avoid cloud, birds etc interference. You can also get light censor chips connected directly to motor drivers for 2-3€ from Ali for this specific purpose - but i dont think they have any sleep interval.
Around 30 years ago, I was involved in a project doing low-budget energy solutions in Belize, using recycled materials. One project was a solar collector, much like the one here.
An old satellite dish was used with hundreds of small square mirrors, cut from common bathroom mirrors. The focal point, however, was not reflected but suspended from the edges of the parabolic dish. The result was so successful that it proved to be downright dangerous in the hands of the inexperienced users it was intended for.
Why you chose paint insted of space blanket? I think second can be more effective
But anyway project looks cool
I boggled by how you have the time and energy to do this, even more so by how you take the time to make such a great video about it! Well done, sir!
have you thought about using a "black body box" collector instead of the plate?
I absolutely understand that people who make these are way more knowledgeable about them than I am, but, my thoughts:
- 1: really, all you'd need is the mid point height for noon, and sunrise and sunset; cause then you can just have a single gear controlling it, and a limited range (unlikely to meet or exceed 180*); which means fewer components, less moving parts, and cheaper/easier to maintain
- 2: add some kind of self balancing aspect to it; basically best I can figure is a heavy enough ball weight, that slides along a track to keep the center of gravity low, so the thing won't randomly tip over from the top
- 3: more nitpicking than anything else, I'd close the gaps between the mirrors, lol
what I *am* curious about, is if maybe this type of solar generator would maybe be better than regular panels? if so, this could be far better to implement than panels, *and* has the ability to be hidden as needed (or even super decorative/decorated). Cause the panels just like bland generally. And, I'm curious, are you trying to get it to boil water and turn it into steam, or is there something else to it? Cause I was thinking if we did the molten salt solar plants on a small scale you could do well with improved power generation for homes.
Shape the mirror before you coat it.
I was thinking the exact same thing.
Have you ever tried to put window tint/film on a curved surface like that? Tint does fine when curved in one direction, but sucks getting it to lay down flat in two.. without a LOT of heat from a heat gun you'll never get it to lay down flat on a parabolic shape.
Concerning the heat collector; you also could have made a copper plate and onto soldering annealed copper tube, that can be bouht from every plumber around the corner.
Easily made and you would have the connections for the hoses wich transport the heated medium.
For the medium i would suggest regular antifreeze wich is used in a car, it has the ability to extract heat better than water, has no minerals in it and is usable in wintertime.
I also would paint the surface matt black for better absorption.
I am afraid that the plexi back of your heat collector cant handle the temperature, you would be surprised how hot it can get.
2:25 the gold chrome paint looks to be bronze or brass based. So you are really comparing silver chrome to copper.
I’d put a temp sensor in the aluminium block. If it gets too hot, you can position the array away from the sun to cool it down.
rub the aluminum disk with really fine grit sandpaper and then rub some artist charcoal all over it.
Is that also heat resistant that you know of?
@@ConceptCraftedCreations I'm sure that because the charcoal is carbon it would combust easily especially as a powder.
@@ConceptCraftedCreations since it's pretty much pure carbon, it shouldn't burn, but should increase the amount of light energy being absorbed into the aluminum. You could also just hold the sun facing side of the aluminum over a campfire until it collects a good coating of soot.
@@ConceptCraftedCreations anodize it. DONE!
I live in Southern Utah near Zion national Park. Directly over our family cattle ranch gets well over 300 days of zero cloud sunlight a year. (Topography)
I might be your first customer it would be a beautiful backdrop for ultimate proof of concept
Very cool keep it up. Subscribed and followed and shared. Thank you.
Concept crafted creations I listened to this video and i KNEW you were from the Netherlands because the ENTIRE time you are speaking I can hear Bas Rutten. You and he sound VERY similar.
Anything I would have done? Not use gold and silver paint for one. When it comes to energy, paint is not the same as the actual materials; it's a case of pigment versus metallic elements. Sure, I get that neither one is cheap, but you can only go so far with just substitutes.
I get what you mean! What's your opinion on the test with the laser to test reflectivity if i may ask?
@@ConceptCraftedCreations Seemed accurate enough to me, so kudos on that. Seriously though, real silver mirrors will beat just about any substitute in this kind of situation.
@@ConceptCraftedCreations Gold paint, isnt the same color, nor reflectivity, of high purity Gold. For that test, you should use Gold-Leaf. Gold Leaf, is real gold.. just incredibly thin... making it semi-affordable, for coating things like Picture Frames.
I feel as though the springs behind the mirrors would be a problem in windy environments. Not being fixed, they allow travel along the mirror's support directions with any force applied to the face of the mirrors; thus, throwing off your angles of reflection.
I think Austrialia experimented with this idea before on a larger scale. I don't remember the reasons the project failed to take off.
4:00 It kinda looks like the Lesser Ark from Halo 3.
Thought the same thing
Excellent ! I love your solar ground tracker! and the hexagonal tiling of the parabola!!!
I would scuff the aluminum heat exchanger for a matte finish or apply a non insulating dark coating to maximize the energy absorption.
Springs aren't cheep?!? Wft!?!
Yeah wtf, I am confused 😕
Addicted to 3D printing.
Here in the states you can buy a bag of 100 springs, depending on size and material, for well under $100(probably
Nice Dutch accent.. I am from Canada but both of my parents were from the Netherlands.. :) Can't wait for the next video!
Two Russian youtubers made sun tracking based on math, location and date. They decided that tracking on light resistors was not a good fit
Thing is, is this contraption precise enough to make use of that though? This solution might not be ideal, but might be good enough with what's available.
Some comments:
1. To really copy the James Web design, you would not need one symmetrical parabolic shape, but instead the right off-axis section of a much larger parabolic for each mirror segment. Though it is rotationally symmetrical in your case, which means one shape for the inner ring of segments and one different shape for the outer ring.
2. For the purpose of just focusing the light, you could also put your absorber at the position of the secondary mirror, James Webb has the secondary mirror only to keep the spatial information of its images, it is not necessary to help in the collection of light.
3. If your mirror works well, your target will be much too large. The spot of light should not have a final diameter too much beyond 1-2 cm. As you have it built now, with the target the same size of each of the mirror segments, you could have achieved that without any curvature on the segments at all, just by aligning all flat segments to reflect onto the center without focusing.
4. If you want to heat water just to get hot water, instead of running a thermo-electrical engine, a wide cylindrical mirror focusing light along one axis onto a black tube will be just as efficient, and overall much easier.
This is insane, can you please include project development and experiment timelines in your videos?
If your committed to using plastic first surface mirrors, look into vapor deposition to apply an aluminum layer onto them.
Exposed for surface mirrors are probably going to be a mistake.
You shouldn't use plastic to back you heat exchanger. Use metal and rtv to seal the joint between the two
9:58 so many simple mistakes made. Why not apply the film after shaping the panels?
Thank you!!!!!!
Haha that's exactly what I wondered?
It seems like such an ill-thought out project. Why not get a metal plate over the heat sink? Why not use metal springs if youll spend $170 on the heat sink anyway?
@ i was confused too
Pretty cool, have you ever thought of electroplating the plexy glass after it's formed to create your mirrors?
Great project! A cheaper and faster solution than the central disk would be flexible copper tube, coiled up in a flat disc shape. Then also make it matt black as many already suggest.
You should use the same kind of rotating mechanism for the vertical as the current horizontal. One flat disk and one vertical disc. Attach the whole set up to the vertical disk and add a counter weight to the opposite side. Adding 4 small solar panels to opposite sides would allow you to make a tracking system. If you angle them backwards, like \____/ where the dish is facing down, and have them each run motors that turn the dish towards the solar panel, it will automatically track the sun. They can be very small and weak motors to since the sun moves pretty slowly, so you can put in a 100 to 1 gear ratio.
Just a thought, i might be wrong, but painting the heat absorbing plate a matte black might help instead of reflecting the light out of the dish with the polished aluminum.
I would thermally insulate the rear of the collection plate, maybe with fiberglass insulation to prevent heat loss out of the back.
My dad made an insulated box with a copper hot water cylinder in it, two sides of the box hinged open to expose the 200 liter cylinder to the sun as a solar hot water heater.
On the first day we opened the cylinder it was very overcast and he didn't think we would get much of a result.
Sitting in the house at dinner we could hear a rhythmic noise which got louder and louder.
It was the water in the cylinder boiling and blowing a stream of boiling water into the sky.
There were many occasions where the water from the hot tap was almost boiling.
Closed up the heat was contained for three days.
A few things i noticed:
1. The parabola molded disks aren't serving much benifit because your collecter is relatively large.
2. The reflective film is likely much worse at reflecting heat than other accessable materials. (My pick would be a reflective desert safety blanket)
3. The aluminum collector loses a large amount of heat because its reflective. Ideally your collector should be dark black to maximise absorbtion. Darkening your existing part can be done easily with an aluminum blueing kit.
4. TPU degrades quickly in UV light, making the printed springs less than ideal for longterm, outdoor use.
5. Clearly a lot of time and passion is being put into this project. Dont let complainers like me stop you from persuing creative ideas, and making discoveries!
1. As others have said; your heart collector stood be black and made of copper. A copper-bottomed cooking pot would probably work.
2. You don't need to shape the individual mirrors. Just point them at the secondary reflector. If not good enough, consider using smaller triangles instead of big hexagons.
3. Add a counterweight to take the stress off of that hinge.
4. How will that big disk handle the wind load on gusty days?
5. If you changed it from a disk to a parabolic trough that focused on a pipe instead of a secondary reflector you would only need to adjust one axis throughout the day instead of two.
6. Instead of springs just use a bolt with 4 nuts and a couple of rubber washers.
Somebody has probably already covered this, but I think it will be extremely difficult to create a secondary mirror that will reflect the light from all the primary mirrors to a single point. As many have suggested, putting the collector in the position of the secondary mirror would be simpler.
I gotta say, I haven't seen someone design a system intended to create extreme heat with the sun and proceed to use wood and plastic parts that are prone to deforming or burning under high heat. Particle board like that also tends to fall apart if it gets wet while outside.
Extruded aluminum is pretty cheap and easy to work with, but suffers none of the problems of wood.
Also, use a cabinet rotating table instead of a huge and expensive bearing. You need a thrust bearing and used a rotational bearing instead. Cabinet "lazy Susans" are very common and cheap, they are not precise instruments but that shouldn't matter here.
Also testing on real gold and silver mirrors is pretty redundant when you're not using a real gold/silver mirror on the final product. Reflective window film has completely different properties than real silver. If you want to use real silver, nilered/nileblue has made some videos on making a silver mirror finish on a variety of materials which could likely be repurposed for this application.
Use soda lime glass for superior surface roughness and coat electrolessly which is used for creating mirrors. Soda lime will soften at lower temps arong 570 C
Either use polished dollar store aluminum cookie sheets or apply the mirror film after shaping the mirrors using water and a heat gun