@@rbp365 ⚠️ God has said in the Quran: 🔵 { O mankind, worship your Lord, who created you and those before you, that you may become righteous - ( 2:21 ) 🔴 [He] who made for you the earth a bed [spread out] and the sky a ceiling and sent down from the sky, rain and brought forth thereby fruits as provision for you. So do not attribute to Allah equals while you know [that there is nothing similar to Him]. ( 2:22 ) 🔵 And if you are in doubt about what We have sent down upon Our Servant [Muhammad], then produce a surah the like thereof and call upon your witnesses other than Allah, if you should be truthful. ( 2:23 ) 🔴 But if you do not - and you will never be able to - then fear the Fire, whose fuel is men and stones, prepared for the disbelievers.( 2:24 ) 🔵 And give good tidings to those who believe and do righteous deeds that they will have gardens [in Paradise] beneath which rivers flow. Whenever they are provided with a provision of fruit therefrom, they will say, "This is what we were provided with before." And it is given to them in likeness. And they will have therein purified spouses, and they will abide therein eternally. ( 2:25 ) ⚠️ Quran
That fresnel lens reminds me of the time my back window was broken out on my old S-10. A friend hit the gas instead of the brakes on a four wheeler we were loading and bam, there went my window. It was going to rain the next day so I took an old junk tv apart and cut out the screen to fit, secured it with black duck tape. It actually looked pretty cool! The next day it kept the rain out on the way to work. Then the sun came out while it was in the parking lot. The center of my dash including the radio looked like someone had took one of those big propane torches and melted it. That's where I learned what a fresnel lens was.
😂 yeah my kids laughed at me for putting a sheet over it (I had mounted a Fresnel lens in a frame on a stand) when I put it in the shed...then I boiled a 2 oz lead fishing weight in under a minute...they didn't mock me anymore! 😎
Great to see you again Dan & Denise, welcome back. Hope things are good. Just heard about a possible storm ~~~ May you & all the folks, animals, critters be safe Kieron from uk
Hi Tim, we are prepped for now. Tomorrow we migrate some stuff to our storm shelter. Hope it will be a big nothing but we are as ready as possible. THANK YOU for the nice message.
Greetings from Panama City. Love your videos and am glad your back. When I'm down you way I would like to meet you and share ideas. Stay safe in the storm.
The solar energy available via a Fresel lens, parabolic reflector, or similar device, is a linear function of its effective aperture. An effective aperture of one four times greater will transmit four times as much power as the smaller. You will get no more power out of a passive device than what you put in, and with physically realizable devices you will get less depending upon the losses within the device itself.
Very interesting and informative....damn it..and to think about how many projection TV's I have recycled...I wish I'd saved the screen's...but I did save the lenses inside...they make very good magnifiers too
Dan, great to have you back. I've missed you guys. I have one question: You said that the lens "absorbs" some of the light. Wouldn't that be that it "reflects" some of the light?
Hi, thank you for the nice comment! I just added an annotation. You are correct, they also reflecting light. Because they appear a lighter color, the three lenses are reflecting more than absorbing. Thank you for pointing that out!!!
It is pure coincidence that I saved these things. Of course if I keep my eyes open, people give these projection TVs every so often on Facebook Market place. The two I got are as big as the large one you have. Well, them three lenses that project the lights are magnifying lenses. And those puppies can focus the Sunlight in the size of the tip of a nail big time. The sheet of plywood I was focusing the sun on at sunset was burning smoking in 10 seconds.
I saw this video sometime ago. Today my friend picked up a projection TV that has an intact large lens. I'm sending this video to him to show why I wanted it I just couldn't let the garbageman take it. It went against my grain
Hi, Dan! Could you show us how to cook with a space blanket (like a solar oven, while keeping the blanket intact) ? Or, how to make a Fresnel lens, sometime? Thanks.
What if you were to focus the fresnel lens at a parabolic mirror? Or an array of that setup? Could you amplify the sun then? Direct sunlight reflected at a specific point? I think your boiling water videos are awesome...nuclear power without the radiation...or a steam engine...i live not far from you and would love the opportunity to have you for a day to show my kids about this stuff.
It depends on a number of factors. The radiation pattern of the lens for one. The best efficiency for a parabolic reflector is when the feed’s (len’s) pattern is about 10 dB down at the edge of the reflector. Also an offset reflector maybe more efficient in this case since there’s less blockage from the F lens.
hey man! glad to see you're still enthusiastic about these topics! It's still an interesting topic with many useful applications :) This makes me wonder if you could use something like this as a way to track sun for solar panels by reflecting and condensing light onto a solar panel, thereby having a lighter object to move and conserve energy.
What if you set up 2 lenses one very big , enough for example to have a very large focal point area (for example say the area of the focal point is 12 inches.. the second frenel lense will be the exact size of the large lenses focal point in this case 12 inches.. this means the entire area of the 2nd lense will already be concentrated light.. wouldn't that further amplify the power?
It does, but not much. I did that with my last lens because it protects the grooves from scratches and is much easier to clean. Some birds seem to believe I build it for them to sit on on the frame and poop on the lens...
Dan, thanks for another great video. May I ask: is this small clear Fresnel lens you used in this video really capable to bring the 6-inch cooking pan with food to the cooking temperature? What is it size? Just wonder how much sun power does it collects in your place on a sunny day, in kW.
Dude(s)! I just bought a spot fresnel lens from you! I thought the name looked familiar so I went back and looked. I know I could google it but is it possible to use, what I think is a linear fresnel lens from a PC monitor, as a good solar collector/concentrator?
Hey Dan, another great video ! Hey I was wondering if you ever followed up on making /marketing the gel fresnel lens? The kind you could roll up when not in use and then put it on a plastic sheet or glass when you need it. I thought that was a great idea.
Hey there Dan, always enjoy your videos. Would a large focal length fresnel lens work for boosting a smaller solar panel, assuming you could deal with the heat dissipation?
Yes: th-cam.com/video/-yh1q59a1h0/w-d-xo.html The issue with this is tracking. A solar panel alone works off axis to the sun pretty good or optimal with simple tracking. When you depend on the concentrated sunlight optimal tracking is required. This is one reason why CPV has not gained ground as regular PV prices have dropped. The heat removal and heliostat configuration is easily offset by just adding regular panels. th-cam.com/video/2438vytA4Po/w-d-xo.html I sort of saw this coming. CPV is awesome for space projects but not financially competitive on the ground. Fresnel lenses and parabolic mirrors have a huge advantage over regular PV for heat applications. For electricity, regular PV seems to be the way to go now. No tracking, no moving parts and plug n' play.
The only way you can do any better is if you get FIBER OPTIC that is concentrated into the receiver side delivered to the other side or the delivery side. Get enough you can have some power. BUT Fiber optic had refraction the longer you run it so you are limited to length of transmission. A lot of people don't know that fiber optic will deliver all the light IR all the energy with some loss due to refraction.
Good afternoon. I thought about how a Fresnel lens can enhance a solar pane as well as add heat to a sand battery. If a Fresnel lens was positioned above a solar panel, the solar panel would become very hot. Instead of allowing the solar panel to absorb so much heat, why not attach antifreeze filled pipes to the back of the solar panels. Then somehow transport the hot antifreeze from the solar panel to the sand battery. The sand battery could absorb the excess heat. This sand battery could be stored for future winter heat.
Sun-sand-steam-electricity is a very interesting pipeline. You could also probably make a sand battery quite easily on BLM land in the USA and heat the thing in the day and use it to stay warm in the night. Wonder what the best way to kit that would be? Small heat-resistant bag/folding box for the sand, and in-out ports for air. Wonder what volume of sand would keep a small camper warm for a night assuming good weather during day.
@@SOGHIH I live in a mobile home. So I would need a small portable sand battery. I was thinking about how the Fresnel lens would increase the output of a solar panel. I was also well aware that the heat generated by the Fresnel lens could damage the solar panel. That's why I thought about the idea of using antifreeze filled pipes to remove the excess heat from the solar panel. Then I thought, why should I allow the heat from the solar panel go to waste. That's why I decided to transport the excess heat to a portable sand battery. That excess could be stored for months in a sand battery. Then the heat could be used during the winter months.
Hey Dan! glad you are posting again, I am a fan of your channel. I was curious about the implications of using a lens or a parabolic mirror to power a TEG/ peltier plate. (Such as that ones made by Devil watt). These generators are probably safer than steam engines but usually need very high temperatures. I saw you had an old video about these and how they work but you never had a follow up with your lenses. I'm an amateur, and really just trying to find ways to help reduce my carbon footprint so any help from you (or other TH-cam commenters ) would be appreciated!
Hey Dan, love your videos. I just got one of these lenses the day. I don't really know if its a good one or not. Should I jump into polishing it, or should I just try some experiments and maybe improve it later if needed?
What if you set up a mile-long copper pipe, with most of its length wrapped in thermal insulation, with bare intervals, with MANY Fresnel lenses rigged with a sun-tracking mechanism, focusing an ENORMOUS collective amount of solar heat onto this copper pipeline, so that by pumping air into one end of the pipe, it comes out the other end like a BLOWTORCH, to provide thermal energy for various industrial applications?
Can you make a large container out of glass that is able to hold a large body of perhaps have copper tubes on the inside of the container that have connectors on the outside of the container to heat up, have many lenses from different positions aimed at different hotspots ( the outside connector part of the copper heating tubes), heating multiple places at once to get a larger dispersal of heat in the water tank. Combined with the magnification of the glass around the large container. I'm not sure how large things need to be, but at a large scale ,it's possible for us to heat a large body of water and collect the compressed steam to make turbines spin. A new type of solar energy.
What if you set up 2 lenses one very big , enough for example to have a very large focal point area (for example say the area of the focal point is 12 inches.. the second frenel lense will be the exact size of the large lenses focal point in this case 12 inches.. this means the entire area of the 2nd lense will already be concentrated light.. wouldn't that further amplify the power?
someone tried it. Basically actually smaller focal point diameter, but final net melting power was smaller than with just one big lens. 1. watch?v=xeUI8vPkUqI 2. watch?v=zuthle6k94A
I've been trying to research optimal shape. I have a 65 inch lens that I am going to polish and hopefully make into a spot lens. I am wondering if cutting it in half would be a good idea. It's nearly twice the length as height, so each half would be nearly square. I wonder if that, being more near the shape of a circle, would be pretty close to optimal, or if I should leave it all in one piece.
@SolarCookingGermany do u have any idea of which lense Samsung 4k curved tvs use. Any feedback would be greatly appreciated. I broke mine trying to fix blackscreen. Now I'm intrigued what I can make. Also do the screens have to be kept the initial size or can you make say 4 smaller ones by quartering them? Wishing u well brother. Godbless 🙏 I have another 2 tvs which are not working, one is a plasma tv. Do u know which lenses plasmas use?
Yes, standard telescope optics, the larger the lens, the greater the light gathering capacity. I hear ya. Also the clearer the lens (more reflective the mirror) the more light energy gets transmitted.
One thing you didn't cover was instead of stacking the two lenses, separate them a bit. So essentially mount the small one at 18 inches from the intended target as you mentioned, then place the larger one 36 inches away from the smaller lens. Don't put the larger one at a point that will burn the smaller lens, but back a bit further than that. In this way the smaller lens would be concentrating the partially concentrated light from the bigger lens.
nah its easier then dat jst use simple mirrors to redirect sunlight to get the good angle BEFORE u lense it, cause the source of light always must be perpendicular to the lense not like he is doing at 3:13 wtf..
Dang, I always wanted to bend light with a fresnel lens... Time for a focal plane redesign with someone that can make their own lenses at home... hmmm lol. (Heck, nevermind, your video just gave me a solution to an idea I had in 2011. If it works, I'll let you in on it... Thanks Dan.)
because the sun move u need to adjust the angles of the lense constantly, it need a proper support setup for it to be automated, frames etc. u need a program to run the positioning and motors and alrdy electricity. maybe maintenance, The concept can work if you use the technology as a steam plant, aside from the house, and the free electricity it over produce can serve ecologically in your house in the way you want. sum electrecity is used so it can run itself and you get an over production.
Well.. if you define "make" as harvesting lenses from old overhead projectors or projection TVs to sell them for top dollar by cutting them and adding a wood frame then ok. But the actual manufacturing of the lens itself no they don't.
Hi Brother :) I do hope that everything is going fine with your Projects, I dont know when you are going to show us how and which lenz to use? I am new in this and I apprishiate everything you teach us. Thank you for ever more Interesting video's...and Good Luck :)
Could you use either a concave mirror or fresnel lens to heat up rocks or metal pieces to create an effect similar to that of a charcoal grill? How could that be set up?
what about Fresnel lens used to heat a plate of iron that has a copper tube sandwiched in between two plates and has a tube that goes to an conditioner radiator and the end hose goes back to the heated tube in a cycle. the tube to be filled with oil and each time the oil goes thru the heated section it gets hotter and hotter. a fan can then blow on the radiator to heat the house. a small window unit inside the house.
I have read some solar concentrator farms using carbon dioxide gas to transfer heat. i would choose this personally as gasses move faster, and carbon dioxide is quite inert, if under enough pressure and temperature does have solvent properties though as it becomes supercritical co2. Also other solar concentrator farms using graphite to store heat. Graphite apparently stores heat quite well. It's black and will absorb more of the solar energy. Could always use basalt or black lava rock as a surface to concentrate your solar energy on to. Copper tubing may melt if hot enough. I think... just guessing.... that if you took basalt or graphite and cast it around a few cm thick piece minimum of concrete with the tubing in the middle, you should be okay. To get more efficient and better perhaps more economical use of the solar energy, would be wise to have several windings of copper through the cast section. Could always be a loop... oils are not a bad idea, but i would go gas with the solar, as it could be exceedingly hot, and then the oil burns or vaporizes and that could rupture the system, unless you want to have hot open exposed oil. Definitely recommend gas, and carbon dioxide, which is what some in industry are using. But you could use iron pipe if that's an issue, not sure if that's cheaper. But yeah you could take your tubing for transferring your heat, have a valve at each end. And hook up a bucket with dry ice in it, sealed, with tubing for vent, connected to one of the valves, then other end valve open, and that will remove the oxygen and replace it with carbon dioxide. then at appropriate pressure, close it off.... so maybe also use a pressure relief valve? i don't know. But not difficult. Then just seal up, perhaps solder or braze closed. Could always have this tubing as a long coil, and run a fan through it... get a thermostat hooked up to a fan and voila temperature control.
Why not use ammonia-water like the classic Einstein refrigerator? Heating a house is probably uneccessary in conditions condusive to solar-heating. But you're getting close. It could drive a Sterling engine, heat a water basin, or perform many other potentially useful tasks.
I don't see why not. Just need something that could absorb a lot of heat without burning. I'm thinking water. The lens heats up a water reservoir. Then the steam can be directed through pipes around the house, dispersing latent heat. Then the steam that condensed back to water drains back into the reservoir. In fact, I'm sure there's something like that out there.
stacking them means making the focal point shorter = safer no ? nice to look into this to transform it into a non-harmful useful heating device ... thanks for the insight, useful myth
One correction, when we stack lenses with each other the net power of the lenses become the sum of power of the lenses, power of the lens is the reciprocal of the focal length in meters, so when you stack 3 lenses the net power becomes thrice the value of single one hence 1/3rd the focal length, so theoretically the focal length of the system of 3 lenses is 18/3 cm that is 6cm
from my understanding sunray gave us 1 kw/sq m regardless 1 sheet or 3 stack and doesnt matter how long its focal point i mean 1kw at 2 meter or 1kw at 3 metre it just same from 1 sq meter area lens itself only dictated power by its properties(lens optimal geometry, transparency, transmission lost etc) i dont really understand what do you mean by sum of power n focal lenght, correct me if iam wrong
Hey Dan. I was thinking that if u get closer to the sun by getting on a very tall tower, the fresnel lens beam would be more powerful when the sun is closest
People in Colorado or at high elevations have more power because there is much less fine particulates. In the Winter here in Florida, the results are better because the humidity is lower and the skies are usually clear. I don't think distance is as important as a clear sky. We have noticed about a 10% power increase in the winter.
if colder weather meant lower humidity and less particulate(thus more power), then higher elevation seems more ideal for more power because colder temp (which means lower humidity) is more found at higher elevation. I know that because I used to fly and it got freezing the higher I went
@@GREENPOWERSCIENCE The Earth is around 3 or 4% closer to the sun in winter versus summer. That should translate to about 6 to 8% more power per unit area. Perhaps that has something to do with it. It wouldn't increase the intensity of the focused spot, but the total power would be higher. Still surprised you got 10% more, though, considering the lower angle means it passes through more atmosphere.
I thought it would have a trick to always focalizes in a same direction, maybe one lens to point the light toward the other and the second one to actualy focus. Or some sort of domus.
Would having a linear focal point make the lens more clear increasing the power? Could you take that focal point and direct it into a light pipe to shoot out a Sun laser?
So actuall power of lenses depends only from their size right ? From how much surface they are concentrating sunlight right ? Sorry for my bad english.
Size and lens clarity. Beam type = linear or spot do not affect the "power" but a spot beam does focus better. Because most spot lenses are usually more transparent they have more power.
They do not amplify light so clear glass allows the same or more light in.. Fresnel lenses for windows create a fire hazard. I would just use clear glass.
Try "Totally Awesome" from the Dollar Tree or Wlamart. Drench full strength and set for a few then hose off. If it is yellowed from not being UV stable it will help a bit. If it is yellowed as a new find, that is from the lens being in a smokers environment and the spray works like magic.
you would have 2 to 3 different focal points, he commented on it in the vid... only if you use para mirrors to redirect the light all to one focal point, will it do anything more...
For one of the lens you said that to focus it needed to be approximately 18 inches above the target. So what if you placed another lens 18 inches above that lens.
Can u use a parabolic satellite dish to concentrate the light through the lens to make it even hotter? New sub brother. Love from Scotland, Godbless. 🙏
You could, but it would be less efficient because the lens would block the light that hits the dish and also the focus would be off because the fresnel works with parallel rays of light.I used to play with these as a kid, but I’m not an expert, so this is a semi-informed opinion.
@@markewing10 thanks for the reply. Jst retrieved my first lense out a TV I had broken earlier today. I'm hoping it will be one of the better ones. Unfortunately it's been storms in Scotland todau so I will need to wait for the sunshine. Once it's framed I will have some fun, Experimenting.
Funnily enough, I had this same thought today.... Using a parabolic reflector similar to a mirror to essentially change the direction or channel sunlight... And then use the lense towards the end of the beam to fully concentrate it. I came to this idea today when playing with my array of solar mirrors and using the fresnel lense with them
No, you would get less because the lens would absorb some of the light before it got to the panel. And if you focused the lens on the panel at its focal length as opposed to placing it directly on the panel, assuming you didn't burn a hole through the panel, the shadow around the focal point would pretty much cut your power to zero. The only way to get more power from a panel is to add more light, typically through using mirrors or living in a drier/less air-polluted climate.
Robert Polito The way that works is you shrink the solar panel to the size of the focal point to save money on the photovoltaics and get higher PV efficiency. You can look up concentrated PV for details.
Yes but at a much lower efficiency...i.e. an overcast day, the sunlight being concentrated would be at a lower over all volume....similar to the clear lens vs the foggy lens.... also ambient light coming through a window in a dark house... the lens would focus it... again at a much greatly reduced efficiency
@@slthbob You seem to be annoyed, for some reason. It doesn't depend on the level of light, but rather its quality, so to speak. The lens projects an image of the sky on to the ground. If the light is completely diffuse, as it would be on most overcast days, then almost the entire sky would be projected on to the ground. This means it would have no focusing ability. If the clouds are thin enough, to let the sun's image show, then there can be some concentration of the light. But otherwise, there isn't. What am I not keeping up with?
indeed. polyethylene can be used even. i think the biggest thing with working with enough heat though and plastics is to have the lenses to the side, as hot air rises, and perhaps a fan or sacrificial plastic barrier before the focal point?
That'd be some tricky math. Lenses not being as clear as window glass, it would lessen the total amount of sunlight reaching the inside because of absorption. But perhaps there is a way to increase the efficiency of the conversion from light to heat by focusing the lens on some heating apparatus. My instinct says it probably wouldn't work, but I don't have the knowledge to prove it.
Use black spray painted containers that you can seal. Fill them with water, close them up, and they will absorb heat giving it back off as the sun disappears. A 2 liter bottle will work, well many 2 liter bottles will work. As far as how many, I do not know the math. Obviously it would depend upon the size the the green house, external temps, etc. There is another method involving, a rock filled hole dug inside of the green house which has a pvc pipe placed inside of the hole with the rocks surround the pipe. It has been a while since I have looked at either.
Info on Spot Lenses:
greenpowerscience.com
fresnel lens in a survival situation :D :D :D you gotta be kidding me! Nice video BTW!
These could be good to prank people at the beach with. I'm getting my friend tomorrow with one!
What is the minimum fresnell lens size that will melt aluminum the size smaller than the concentrated focal point?
Question. Do fresnel lenses allow UV to go through. I cannot find an
@@rbp365 ⚠️ God has said in the Quran:
🔵 { O mankind, worship your Lord, who created you and those before you, that you may become righteous - ( 2:21 )
🔴 [He] who made for you the earth a bed [spread out] and the sky a ceiling and sent down from the sky, rain and brought forth thereby fruits as provision for you. So do not attribute to Allah equals while you know [that there is nothing similar to Him]. ( 2:22 )
🔵 And if you are in doubt about what We have sent down upon Our Servant [Muhammad], then produce a surah the like thereof and call upon your witnesses other than Allah, if you should be truthful. ( 2:23 )
🔴 But if you do not - and you will never be able to - then fear the Fire, whose fuel is men and stones, prepared for the disbelievers.( 2:24 )
🔵 And give good tidings to those who believe and do righteous deeds that they will have gardens [in Paradise] beneath which rivers flow. Whenever they are provided with a provision of fruit therefrom, they will say, "This is what we were provided with before." And it is given to them in likeness. And they will have therein purified spouses, and they will abide therein eternally. ( 2:25 )
⚠️ Quran
That fresnel lens reminds me of the time my back window was broken out on my old S-10. A friend hit the gas instead of the brakes on a four wheeler we were loading and bam, there went my window. It was going to rain the next day so I took an old junk tv apart and cut out the screen to fit, secured it with black duck tape. It actually looked pretty cool! The next day it kept the rain out on the way to work. Then the sun came out while it was in the parking lot. The center of my dash including the radio looked like someone had took one of those big propane torches and melted it. That's where I learned what a fresnel lens was.
😂 yeah my kids laughed at me for putting a sheet over it (I had mounted a Fresnel lens in a frame on a stand) when I put it in the shed...then I boiled a 2 oz lead fishing weight in under a minute...they didn't mock me anymore! 😎
@@tatchik77 🗿
LoL mate
Great to see you again Dan & Denise, welcome back. Hope things are good.
Just heard about a possible storm ~~~ May you & all the folks, animals, critters be safe
Kieron from uk
A great to see you back Dan & Denise, I pray you'll all be ok during the coming hurricane Matthew.
Stay safe.
Wow. Answered lots of great questions. Thank you.
You guys stay safe if you get hit with the storm. All the best!
Hi Tim, we are prepped for now. Tomorrow we migrate some stuff to our storm shelter. Hope it will be a big nothing but we are as ready as possible. THANK YOU for the nice message.
Just a little wind, Florida is very fortunate. Thoughts are with Haiti:-)
Greetings from Panama City. Love your videos and am glad your back. When I'm down you way I would like to meet you and share ideas. Stay safe in the storm.
Welcome back. We missed you.
Hi, missed everyone too. We have had a lot of "Life" on our plate lately. Thank you for the welcome back!!!!!!!!
Keep the vids coming! I miss all of the old projects and experiments!
glad you're uploading again : )
Great to see you Dan, stay safe during the storm. Looking forward to more videos.
Thank you moonreft
The solar energy available via a Fresel lens, parabolic reflector, or similar device, is a linear function of its effective aperture. An effective aperture of one four times greater will transmit four times as much power as the smaller. You will get no more power out of a passive device than what you put in, and with physically realizable devices you will get less depending upon the losses within the device itself.
Very interesting and informative....damn it..and to think about how many projection TV's I have recycled...I wish I'd saved the screen's...but I did save the lenses inside...they make very good magnifiers too
Dan, great to have you back. I've missed you guys. I have one question: You said that the lens "absorbs" some of the light. Wouldn't that be that it "reflects" some of the light?
Hi, thank you for the nice comment! I just added an annotation. You are correct, they also reflecting light. Because they appear a lighter color, the three lenses are reflecting more than absorbing. Thank you for pointing that out!!!
It is pure coincidence that I saved these things. Of course if I keep my eyes open, people give these projection TVs every so often on Facebook Market place.
The two I got are as big as the large one you have.
Well, them three lenses that project the lights are magnifying lenses. And those puppies can focus the Sunlight in the size of the tip of a nail big time.
The sheet of plywood I was focusing the sun on at sunset was burning smoking in 10 seconds.
I saw this video sometime ago.
Today my friend picked up a projection TV that has an intact large lens. I'm sending this video to him to show why I wanted it
I just couldn't let the garbageman take it. It went against my grain
I really look forward to some great new vids!
Glad to see you back, Lord of the Sun
Hi, Dan! Could you show us how to cook with a space blanket (like a solar oven, while keeping the blanket intact) ? Or, how to make a Fresnel lens, sometime? Thanks.
Good to see you back, I love your videos and have learned much from them. Keep up the good work. Peace!
Welcome back!
What if you were to focus the fresnel lens at a parabolic mirror? Or an array of that setup? Could you amplify the sun then? Direct sunlight reflected at a specific point? I think your boiling water videos are awesome...nuclear power without the radiation...or a steam engine...i live not far from you and would love the opportunity to have you for a day to show my kids about this stuff.
It depends on a number of factors. The radiation pattern of the lens for one. The best efficiency for a parabolic reflector is when the feed’s (len’s) pattern is about 10 dB down at the edge of the reflector. Also an offset reflector maybe more efficient in this case since there’s less blockage from the F lens.
hey man! glad to see you're still enthusiastic about these topics! It's still an interesting topic with many useful applications :)
This makes me wonder if you could use something like this as a way to track sun for solar panels by reflecting and condensing light onto a solar panel, thereby having a lighter object to move and conserve energy.
That clears up alot of questions and thoughts i had
great video, a fresnel array is something I had considered but thanks for showing it's a non-starter
This saved me a ton of trial and error. Thank you!
What if you set up 2 lenses one very big , enough for example to have a very large focal point area (for example say the area of the focal point is 12 inches.. the second frenel lense will be the exact size of the large lenses focal point in this case 12 inches.. this means the entire area of the 2nd lense will already be concentrated light.. wouldn't that further amplify the power?
@4everseekingwisdom690 i like the idea, but wouldn't that melt the 2nd lense?
@@BlueCrow89 possibly but I'd love to try it... For science if course
Thx never daw one of these before. Great info and well demonstrated. Be safe out there.
Hey, how is it that your channel is not monetized???? It seems like your content is original and you seem to have plenty of views.
Does it negatively affect the lense performance to include the clear plexiglas in the frame as an anti-sag support when testing in sunlight ?
It does, but not much. I did that with my last lens because it protects the grooves from scratches and is much easier to clean. Some birds seem to believe I build it for them to sit on on the frame and poop on the lens...
Miss this "OG" channel, GREAT STUFF! Dan always reminded me of Bruce Dickinson from Iron Maiden.☺️👍
Dan. itś good to have you back. keep up the good work.
Dan, thanks for another great video. May I ask: is this small clear Fresnel lens you used in this video really capable to bring the 6-inch cooking pan with food to the cooking temperature? What is it size? Just wonder how much sun power does it collects in your place on a sunny day, in kW.
Where we have to buy this fresnel lens?. 2×2 feet i want. Please tell me
Dude(s)! I just bought a spot fresnel lens from you! I thought the name looked familiar so I went back and looked. I know I could google it but is it possible to use, what I think is a linear fresnel lens from a PC monitor, as a good solar collector/concentrator?
Hey Dan, another great video ! Hey I was wondering if you ever followed up on making /marketing the gel fresnel lens? The kind you could roll up when not in use and then put it on a plastic sheet or glass when you need it. I thought that was a great idea.
Hey there Dan, always enjoy your videos. Would a large focal length fresnel lens work for boosting a smaller solar panel, assuming you could deal with the heat dissipation?
Yes:
th-cam.com/video/-yh1q59a1h0/w-d-xo.html
The issue with this is tracking. A solar panel alone works off axis to the sun pretty good or optimal with simple tracking. When you depend on the concentrated sunlight optimal tracking is required. This is one reason why CPV has not gained ground as regular PV prices have dropped. The heat removal and heliostat configuration is easily offset by just adding regular panels.
th-cam.com/video/2438vytA4Po/w-d-xo.html
I sort of saw this coming. CPV is awesome for space projects but not financially competitive on the ground.
Fresnel lenses and parabolic mirrors have a huge advantage over regular PV for heat applications. For electricity, regular PV seems to be the way to go now. No tracking, no moving parts and plug n' play.
The only way you can do any better is if you get FIBER OPTIC that is concentrated into the receiver side delivered to the other side or the delivery side. Get enough you can have some power. BUT Fiber optic had refraction the longer you run it so you are limited to length of transmission. A lot of people don't know that fiber optic will deliver all the light IR all the energy with some loss due to refraction.
respect for this man
What if you increase the diameter of the fiber
Are you still experiment with solar cooker?
What is your latest cooker project ?
Thanks for this clear advice that debunks the myths.
Good to see you back.
Good afternoon. I thought about how a Fresnel lens can enhance a solar pane as well as add heat to a sand battery. If a Fresnel lens was positioned above a solar panel, the solar panel would become very hot. Instead of allowing the solar panel to absorb so much heat, why not attach antifreeze filled pipes to the back of the solar panels. Then somehow transport the hot antifreeze from the solar panel to the sand battery. The sand battery could absorb the excess heat. This sand battery could be stored for future winter heat.
Sun-sand-steam-electricity is a very interesting pipeline. You could also probably make a sand battery quite easily on BLM land in the USA and heat the thing in the day and use it to stay warm in the night. Wonder what the best way to kit that would be? Small heat-resistant bag/folding box for the sand, and in-out ports for air. Wonder what volume of sand would keep a small camper warm for a night assuming good weather during day.
@@SOGHIH I live in a mobile home. So I would need a small portable sand battery. I was thinking about how the Fresnel lens would increase the output of a solar panel. I was also well aware that the heat generated by the Fresnel lens could damage the solar panel. That's why I thought about the idea of using antifreeze filled pipes to remove the excess heat from the solar panel. Then I thought, why should I allow the heat from the solar panel go to waste. That's why I decided to transport the excess heat to a portable sand battery. That excess could be stored for months in a sand battery. Then the heat could be used during the winter months.
@@speedlearner they do make cooled solar panels. Search for the following video:
"Warming Up By Cooling Down Your Solar Panels "
have been watching these videos for a short while and learned a lot from this guy who is very good and informative, thanks
Hey Dan! glad you are posting again, I am a fan of your channel. I was curious about the implications of using a lens or a parabolic mirror to power a TEG/ peltier plate. (Such as that ones made by Devil watt). These generators are probably safer than steam engines but usually need very high temperatures. I saw you had an old video about these and how they work but you never had a follow up with your lenses. I'm an amateur, and really just trying to find ways to help reduce my carbon footprint so any help from you (or other TH-cam commenters ) would be appreciated!
Andrew Angerer sounds like a good idea, but much do you pay for enough peltier devices to get, say, 1 kW?
Gracias Daniel.
Great tutorial. Much appreciated
Hey Dan, love your videos. I just got one of these lenses the day. I don't really know if its a good one or not. Should I jump into polishing it, or should I just try some experiments and maybe improve it later if needed?
Spray WD-40 on the smooth side. Even if it is not a great lens buffing helps a lot. A dull linear in most cases can become a dull spot.
Thanks for the reply.
What if you set up a mile-long copper pipe, with most of its length wrapped in thermal insulation, with bare intervals, with MANY Fresnel lenses rigged with a sun-tracking mechanism, focusing an ENORMOUS collective amount of solar heat onto this copper pipeline, so that by pumping air into one end of the pipe, it comes out the other end like a BLOWTORCH, to provide thermal energy for various industrial applications?
It's already done , but uses thermal oil and generates electricity
Did you ever come up with a good solar powered Stirling Engine?
Can you make a large container out of glass that is able to hold a large body of perhaps have copper tubes on the inside of the container that have connectors on the outside of the container to heat up, have many lenses from different positions aimed at different hotspots ( the outside connector part of the copper heating tubes), heating multiple places at once to get a larger dispersal of heat in the water tank.
Combined with the magnification of the glass around the large container.
I'm not sure how large things need to be, but at a large scale ,it's possible for us to heat a large body of water and collect the compressed steam to make turbines spin.
A new type of solar energy.
It makes sense ! 🤔🧐😎😀
Bro, I literally had the exact same idea. We should start a business.
@@siafu-1764 I'm good for working on this project
What if you set up 2 lenses one very big , enough for example to have a very large focal point area (for example say the area of the focal point is 12 inches.. the second frenel lense will be the exact size of the large lenses focal point in this case 12 inches.. this means the entire area of the 2nd lense will already be concentrated light.. wouldn't that further amplify the power?
someone tried it. Basically actually smaller focal point diameter, but final net melting power was smaller than with just one big lens.
1. watch?v=xeUI8vPkUqI
2. watch?v=zuthle6k94A
@@micha3624 I'll check it out thanks.. I was thinking it might melt the second lens but I'm not surprised the answer is actually less power
great info,, you do a good job explaining . Thanks, Russ , from the north woods of Maine
I've been trying to research optimal shape. I have a 65 inch lens that I am going to polish and hopefully make into a spot lens. I am wondering if cutting it in half would be a good idea. It's nearly twice the length as height, so each half would be nearly square. I wonder if that, being more near the shape of a circle, would be pretty close to optimal, or if I should leave it all in one piece.
You can't cut a Fresnel lens in half, that would leave you with a destroyed lens
I'm interested to know the results of your polishing and what you used.
@@davidmuth4571
My whole project was a massive, disappointing failure.
you need to make a concentration dome but its very big you need the large mirrors etc. but you can stack alot alot of lense
It is really interesting and inspiring. My question is where and how could one find these lenses?
Thanks. Get+ Ethio
Old dlp tvs
The old big flat screen tvs your rich single uncle had.
Can they be polished to become crystal clear?
@SolarCookingGermany do u have any idea of which lense Samsung 4k curved tvs use. Any feedback would be greatly appreciated. I broke mine trying to fix blackscreen. Now I'm intrigued what I can make. Also do the screens have to be kept the initial size or can you make say 4 smaller ones by quartering them? Wishing u well brother. Godbless 🙏 I have another 2 tvs which are not working, one is a plasma tv. Do u know which lenses plasmas use?
Yes, standard telescope optics, the larger the lens, the greater the light gathering capacity. I hear ya. Also the clearer the lens (more reflective the mirror) the more light energy gets transmitted.
One thing you didn't cover was instead of stacking the two lenses, separate them a bit. So essentially mount the small one at 18 inches from the intended target as you mentioned, then place the larger one 36 inches away from the smaller lens. Don't put the larger one at a point that will burn the smaller lens, but back a bit further than that. In this way the smaller lens would be concentrating the partially concentrated light from the bigger lens.
yes and also what about concave and convex lenses that can focus sunlight from a larger area (more directions) than just their surface area?
nah its easier then dat jst use simple mirrors to redirect sunlight to get the good angle BEFORE u lense it, cause the source of light always must be perpendicular to the lense not like he is doing at 3:13 wtf..
Lol. He said the light will always go in a straight line for the most part. Lol.
What if you put a fresnal lens on top and a parabolic mirror on the bottom and focused all the light on the same spot?
Dang, I always wanted to bend light with a fresnel lens... Time for a focal plane redesign with someone that can make their own lenses at home... hmmm lol. (Heck, nevermind, your video just gave me a solution to an idea I had in 2011. If it works, I'll let you in on it... Thanks Dan.)
Is it possible to disperse the heat from a fresnel lens to create safe ambient heating?
I was thinking the same thing.
because the sun move u need to adjust the angles of the lense constantly, it need a proper support setup for it to be automated, frames etc. u need a program to run the positioning and motors and alrdy electricity. maybe maintenance, The concept can work if you use the technology as a steam plant, aside from the house, and the free electricity it over produce can serve ecologically in your house in the way you want. sum electrecity is used so it can run itself and you get an over production.
it's called a glass window...
You make your own fresnel lenses? wow! I assume you won't make a video showing how?
search for "Convert Linear Fresnel Lens to a Spot Fresnel Lens GreenPowerScience" ;)
search for "Convert Linear Fresnel Lens to a Spot Fresnel Lens GreenPowerScience" ;)
That is how they convert them, not how they make them from scratch, which they also do.
Well.. if you define "make" as harvesting lenses from old overhead projectors or projection TVs to sell them for top dollar by cutting them and adding a wood frame then ok. But the actual manufacturing of the lens itself no they don't.
Quite wrong. They have videos showing fresnel lenses which they MAKE themselves, as I pointed out.
frensel lense such an amazing invention. i hope some day to see the first order lens
Hi Brother :) I do hope that everything is going fine with your Projects, I dont know when you are going to show us how and which lenz to use? I am new in this and I apprishiate everything you teach us. Thank you for ever more Interesting video's...and Good Luck :)
Could you use either a concave mirror or fresnel lens to heat up rocks or metal pieces to create an effect similar to that of a charcoal grill? How could that be set up?
what about Fresnel lens used to heat a plate of iron that has a copper tube sandwiched in between two plates and has a tube that goes to an conditioner radiator and the end hose goes back to the heated tube in a cycle. the tube to be filled with oil and each time the oil goes thru the heated section it gets hotter and hotter. a fan can then blow on the radiator to heat the house. a small window unit inside the house.
I have read some solar concentrator farms using carbon dioxide gas to transfer heat. i would choose this personally as gasses move faster, and carbon dioxide is quite inert, if under enough pressure and temperature does have solvent properties though as it becomes supercritical co2. Also other solar concentrator farms using graphite to store heat. Graphite apparently stores heat quite well. It's black and will absorb more of the solar energy. Could always use basalt or black lava rock as a surface to concentrate your solar energy on to. Copper tubing may melt if hot enough. I think... just guessing.... that if you took basalt or graphite and cast it around a few cm thick piece minimum of concrete with the tubing in the middle, you should be okay. To get more efficient and better perhaps more economical use of the solar energy, would be wise to have several windings of copper through the cast section. Could always be a loop... oils are not a bad idea, but i would go gas with the solar, as it could be exceedingly hot, and then the oil burns or vaporizes and that could rupture the system, unless you want to have hot open exposed oil. Definitely recommend gas, and carbon dioxide, which is what some in industry are using. But you could use iron pipe if that's an issue, not sure if that's cheaper. But yeah you could take your tubing for transferring your heat, have a valve at each end. And hook up a bucket with dry ice in it, sealed, with tubing for vent, connected to one of the valves, then other end valve open, and that will remove the oxygen and replace it with carbon dioxide. then at appropriate pressure, close it off.... so maybe also use a pressure relief valve? i don't know. But not difficult. Then just seal up, perhaps solder or braze closed. Could always have this tubing as a long coil, and run a fan through it... get a thermostat hooked up to a fan and voila temperature control.
Why not use ammonia-water like the classic Einstein refrigerator?
Heating a house is probably uneccessary in conditions condusive to solar-heating.
But you're getting close. It could drive a Sterling engine, heat a water basin, or perform many other potentially useful tasks.
I had same thought regarding ammonia based refrigeration, not sure how one would regulate the heat/temp.
I was wondering if the lenses would warm my house (that is made for Texas summers) during those rare winter storms? Shallom you are loved
I don't see why not. Just need something that could absorb a lot of heat without burning.
I'm thinking water. The lens heats up a water reservoir. Then the steam can be directed through pipes around the house, dispersing latent heat. Then the steam that condensed back to water drains back into the reservoir.
In fact, I'm sure there's something like that out there.
Sand
Por favor Dan de vez en cuando un video en español. Gracias.
Voy a trabajar en esa idea para usted. Gracias por el comentario agradable usted.
What better way to make a come back then releasing yet another fresnel lens video?
Very informative and helpful video thanks for sharing
stacking them means making the focal point shorter = safer no ? nice to look into this to transform it into a non-harmful useful heating device ... thanks for the insight, useful myth
No
One correction, when we stack lenses with each other the net power of the lenses become the sum of power of the lenses, power of the lens is the reciprocal of the focal length in meters, so when you stack 3 lenses the net power becomes thrice the value of single one hence 1/3rd the focal length, so theoretically the focal length of the system of 3 lenses is 18/3 cm that is 6cm
from start the focal points he is stacking don't come from light sources dat are perpendicular to the lenses
from my understanding sunray gave us 1 kw/sq m regardless 1 sheet or 3 stack and doesnt matter how long its focal point i mean 1kw at 2 meter or 1kw at 3 metre it just same from 1 sq meter area
lens itself only dictated power by its properties(lens optimal geometry, transparency, transmission lost etc) i dont really understand what do you mean by sum of power n focal lenght, correct me if iam wrong
Thank you for this clear explanation! Great!
Hey Dan. I was thinking that if u get closer to the sun by getting on a very tall tower, the fresnel lens beam would be more powerful when the sun is closest
People in Colorado or at high elevations have more power because there is much less fine particulates. In the Winter here in Florida, the results are better because the humidity is lower and the skies are usually clear. I don't think distance is as important as a clear sky. We have noticed about a 10% power increase in the winter.
Because a hundred feet is so significant in the 93 million miles to the sun.
if colder weather meant lower humidity and less particulate(thus more power), then higher elevation seems more ideal for more power because colder temp (which means lower humidity) is more found at higher elevation. I know that because I used to fly and it got freezing the higher I went
Just build a space-laser.
@@GREENPOWERSCIENCE The Earth is around 3 or 4% closer to the sun in winter versus summer. That should translate to about 6 to 8% more power per unit area. Perhaps that has something to do with it. It wouldn't increase the intensity of the focused spot, but the total power would be higher. Still surprised you got 10% more, though, considering the lower angle means it passes through more atmosphere.
you guys are missed.
I thought it would have a trick to always focalizes in a same direction, maybe one lens to point the light toward the other and the second one to actualy focus. Or some sort of domus.
You video helped a great deal ! Thanks ❤
What is the cost of this lenses
Awesome info! You rock as always.
how did you make the smaller lens? Is it 3d printed or molded or something?
It is a curved mold similar to the press most lenses were once made from. Working on larger versions.
This is cool. I can use one for heating up water for showers for camping
You could, there are other videos on our channel with water heating. Some use lenses and some use simple black water hose.
Would having a linear focal point make the lens more clear increasing the power? Could you take that focal point and direct it into a light pipe to shoot out a Sun laser?
I'm thinking a Fibonacci spiral would take it and bounce it into the center. Tilt it a little and it might go down the length
You would need a ruby rod for the laser. I have tried this before but destroyed the rod. Results unknown because trial and error is very expensive.
So actuall power of lenses depends only from their size right ? From how much surface they are concentrating sunlight right ? Sorry for my bad english.
Size and lens clarity. Beam type = linear or spot do not affect the "power" but a spot beam does focus better. Because most spot lenses are usually more transparent they have more power.
u should try some headlight restore on those murky lenses
Turtle wax polishing compound. One side has texture though.
respect sir!
Could I add one of these to a basement window to get more light? It's West facing and shaded most of the morning... or would it be dangerous?
They do not amplify light so clear glass allows the same or more light in.. Fresnel lenses for windows create a fire hazard. I would just use clear glass.
But if you put it in backwards, would it not diffuse the light, lighting more area with less intensity?
Great to see you back. Hope the storm dodges you
Have you had a problem with the lenses yellowing? I have a 52 inch that has yellowed and want to know if this can be remedied.
Try "Totally Awesome" from the Dollar Tree or Wlamart. Drench full strength and set for a few then hose off. If it is yellowed from not being UV stable it will help a bit. If it is yellowed as a new find, that is from the lens being in a smokers environment and the spray works like magic.
Ok. Thanks. I'll try it. It was from a late 90's Hitachi projection screen TV. I still find them out by the road for p/u occasionally....:)
Is that the "Totally Awesome" window cleaner or something else. There's quite a few products with that name.
what if you built frames to put 2 or 3 lenses in, and experiment with distances between lenses? Then build an adjustable stand? Just curious!
you would have 2 to 3 different focal points, he commented on it in the vid... only if you use para mirrors to redirect the light all to one focal point, will it do anything more...
What would happen if you put a focal point on another magnifier on refocus it into another beam??
For one of the lens you said that to focus it needed to be approximately 18 inches above the target. So what if you placed another lens 18 inches above that lens.
The first lens would focus in the middle of the second lens while shading the rest of the second lens. Less power than using just one.
There are ways to focus the point further, but each process reduces light proportional to the quality of the lens.
Interesting info on Fresnel Lenses
Can u use a parabolic satellite dish to concentrate the light through the lens to make it even hotter? New sub brother. Love from Scotland, Godbless. 🙏
You could, but it would be less efficient because the lens would block the light that hits the dish and also the focus would be off because the fresnel works with parallel rays of light.I used to play with these as a kid, but I’m not an expert, so this is a semi-informed opinion.
@@markewing10 thanks for the reply. Jst retrieved my first lense out a TV I had broken earlier today. I'm hoping it will be one of the better ones. Unfortunately it's been storms in Scotland todau so I will need to wait for the sunshine. Once it's framed I will have some fun, Experimenting.
Funnily enough, I had this same thought today.... Using a parabolic reflector similar to a mirror to essentially change the direction or channel sunlight... And then use the lense towards the end of the beam to fully concentrate it.
I came to this idea today when playing with my array of solar mirrors and using the fresnel lense with them
@@RghnutritionAus great minds and visionaries think alike😉 Godbless brother ❤️
If you lay a FRESNEL LENS on top of a solar panel, would you get more power out of the panel and what % ?
No, you would get less because the lens would absorb some of the light before it got to the panel. And if you focused the lens on the panel at its focal length as opposed to placing it directly on the panel, assuming you didn't burn a hole through the panel, the shadow around the focal point would pretty much cut your power to zero. The only way to get more power from a panel is to add more light, typically through using mirrors or living in a drier/less air-polluted climate.
Robert Polito The way that works is you shrink the solar panel to the size of the focal point to save money on the photovoltaics and get higher PV efficiency. You can look up concentrated PV for details.
Thanks Dan, nice to see ya doing a vid from time to time, say hello from you-tube land to your wife as well.
Denise says hello to everyone. She is looking forward to making videos again too!
Nice! Big thumbs up. You guys rock.
Kind of a dumb question, but does it work with out direct sunlight?
Yes but at a much lower efficiency...i.e. an overcast day, the sunlight being concentrated would be at a lower over all volume....similar to the clear lens vs the foggy lens.... also ambient light coming through a window in a dark house... the lens would focus it... again at a much greatly reduced efficiency
@@slthbob No, on a cloudy day, it wouldn't work at all. It would just display diffuse light everywhere.
@@DANGJOS depends on the level of light during the cloudy day... just like I said silly man... keep up
@@slthbob You seem to be annoyed, for some reason. It doesn't depend on the level of light, but rather its quality, so to speak. The lens projects an image of the sky on to the ground. If the light is completely diffuse, as it would be on most overcast days, then almost the entire sky would be projected on to the ground. This means it would have no focusing ability. If the clouds are thin enough, to let the sun's image show, then there can be some concentration of the light. But otherwise, there isn't. What am I not keeping up with?
@@DANGJOS simple ignorance annoys me... enjoy
Very informative THANK YOU!
It seems like Fresnel lenses should be cheap to produce. You just make a mold with the proper negative of the ridges and press the proper plastics.
indeed. polyethylene can be used even. i think the biggest thing with working with enough heat though and plastics is to have the lenses to the side, as hot air rises, and perhaps a fan or sacrificial plastic barrier before the focal point?
How did you find that big lens?
what is the largest one made can they make a bigger one?
you dont need bigger lense, he is just not aware how to stack them properly, and it takes a very elaborated setup to acheive this.
just out of interest can those lenses be used in any way to heat or help to heat a greenhouse so you don't need to use gas heaters in the greenhouse?
That'd be some tricky math. Lenses not being as clear as window glass, it would lessen the total amount of sunlight reaching the inside because of absorption. But perhaps there is a way to increase the efficiency of the conversion from light to heat by focusing the lens on some heating apparatus. My instinct says it probably wouldn't work, but I don't have the knowledge to prove it.
Use black spray painted containers that you can seal. Fill them with water, close them up, and they will absorb heat giving it back off as the sun disappears. A 2 liter bottle will work, well many 2 liter bottles will work. As far as how many, I do not know the math. Obviously it would depend upon the size the the green house, external temps, etc. There is another method involving, a rock filled hole dug inside of the green house which has a pvc pipe placed inside of the hole with the rocks surround the pipe. It has been a while since I have looked at either.
a ceiling with a grid and plastic would give you puddles of water and they would each give a beam