Solar Evacuated Tube Vacuum Tubes DIY Test in the Sun

[carr869]

Thats pretty neat. Those things have all kinds of possibilities.

[GOP4USA]

How do u make it ?

[advthinker]

we all know that heat wil not traverse a vaccum. the real trick is to use a gas that makes it hotter! look at mars it forms a natural laser because of the co2. the first solar ac was a evcated tube system, that used co2 to increase the temp in the manifolds. eazy to make co2 with vinegar and bakesoda. and put inside of jars to exp. with. dont wait for dan try it yourself.

[johnnythefridge]

@advthinker If heat wont travel through a vacuum. How does the sun warm planet earth ?

[MrTLMora]

Planck Black Body Experiment. For heating. Nifty Keen-O!

[KingLutherQ]

I think the experiment could be flawed. this only shows the greenhouse effect.

the comparison should be a container with a vacuum against a container with plain air or other gases.

[paulj0557]

I feel that all hot water tanks for new residential & commercial builds, should have passive heat exchangers installed in them. This should become mandatory.

One way of supplying the heat exchanger would be to design a ridge vent system that works in two ways. During sunlight, the ridge could be designed to become marginally hotter than the temperature of the ambient attic air. This would naturally draw this air to the vent. It would cool the attic and at the same time heat the hot water.

[jackson593]

i boiled water in a coke can just by leaving it in the sun Thanks AUSSIE sun

[eloid777]

To expand on this idea , why not make diy square glass tubes, cut 2.5"x 4' long

strips of glass 4 per tube. Make a V or U shape trough to help align the glass at right angles use spacers to elevate the glass so the silicon (high temp silicon300 c) seal the glass, leave over night to dry. The silicon the 2 halfs same way when dry. Prepare brass or alunmin end plates with a hole in them for a black gas pipe hole should be larger to allow for expandtion of pipe and place of silicon around the pipe

[eloid777]

use a tire stem for the vaccum port, you can also just obtain the insert of the tire stem and thread into brass or aluminum plate. Also rember to prep clean the glass .. use a belt sand with 100 grid sand paper to soften round over the edges of the glass very quicly, dont apply to much force the sand paper will do the work. Also clean and prep the black gass pipe and paint with flat black metal paint. to creat a solor conductor. Join lenght of vaccum tube as needed insulate exposed pipe

[dbnstrikeman]

Would a parabolic mirror in a vacuum be more efficient or am I missing something?

[xadam2dudex]

if this is part 2 where is part 1 ?

[datzfast]

thank you for the demonstration.

[joulian0720]

Dan , will you be doing anymore updates anytime soon? i am working on pool heater with this concept and would love to see more experimentations.

[struchol]

Good work :D

[youtubasoarus]

So i'm guessing the vacuum acts as an insulator?

[lerch25]

could you explain the physics of why this happens? I am baffled by this

[GREENPOWERSCIENCE]

@lerch25 Hi,

Heat conducts through air molecules. A vacuum has almost none so it keeps heat inside. This is just like a regular vacuum thermos but clear outside and dark inside so sunlight can build heat faster.

[Snither]

@GREENPOWERSCIENCE then why the heat of the sun can reach the earth if space has no air particles????? :S

[Mrbryllis]

@lerch25

Two important things to know which will explain how this works.

1. A vacuum is indeed an insulator. The greater the vacuum, the better the insulator.

2. Most of the energy from the sun arrives as light energy and is converted to heat energy when the light energy strikes any object that is not white. (Ice and snow acts as a mirror and reflects the light.) The light energy stimulates the molecules in the object it is striking to vibrate, hence producing heat.

[edy066]

why dont we have more uses for vacuum seals?

double glazed windows, ovens lined with vacuum walls, houses with vacuum walls rather than pinks batts

we could benefit alot more from this technology

the bottle you made on this video would be excellent for heating up my lunch time soup, maybe even make a cup of tea, saving me money boiling the jug

[TheSporesguy]

That's not even a real comparison. Put the bottle into a chamber without a vacuum so that it's not losing twice the heat as the one in the vacuum chamber. Just the insulation of having a pocket of still air on the outside of the bottle will make it compare with the vacuum chamber. I think the whole vacuum thing is bs, or over rated at least. Make two identical bottles and chambers. Pull a vacuum on one, and not on the other. Lets see the results then...

[4sineweaver2]

Forget the bottle. Use copper pipe. You need pipe for a loop system anyway, right? Now that I'm freezin' I wish I would have tried this experiment during the summer.

[noname7913]

I'm guessing this is an experiment using a vacuum as an insulator to increase efficiency of a boiler. A problem I see with it is the vacuum will create a greater pressure difference placing great strain on the glass bottle. If you try to capture the steam I think it might break. If you don't care too much about the thermos you made, perhaps you can test this in an experiment.

[esnap]

For a control, you could use no vacuum in the housing.

You would find that a bottle just in a green house would perform very well.

[datzfast]

@esnap agreed it would be a more meaning full demonstration. after all the question should be is a vacuum worth the trouble.

[UndefinedUnkown]

use degrees!!!

[UndefinedUnkown]

celcius....

[tonyb24242424]

lol your cold

[Stormrunner0002]

Have you thought of sealing a dome over your mirrors outside of the focal point a installing a coil to be heated at the focal point. The sealed chamber could then be evacuated.

Thanks for triggering the ideas. Good work you do.

[planmix]

interesting...

[sparc5]

Dan,very interesting show us what the heat difference would be without the vacuum, but still in the same contraption. I think your vacuum isn't strong enough to make a very big difference regarding convection cooling. You're mainly seeing air as an insulator I hypothesize.

[unhidden]

The temp diff you have is because the heat can leave non vacuum bottle through convection of the air on the contact surface, while the bottle in the vacuum valve cannot rid heat that way. The vacuum valve preserves the energy better than the other one because of this. Still heat can dissipate through radiation.

[joulian0720]

are there any vids you might suggest to demo this ? I am trying to understand it :)

[emo5derf]

Plus you didnt use the reflector method behind the bottle like you mentioned in your previous video. Still, some wide parabolic shape could probably put 1000W onto that bottle.

[emo5derf]

By parabolic shape I meant just a flat piece of material with a very shiny surface bent to where it will focus the light onto the bottle. Using that method, one evauated tube would collect alot of heat, but it would have to track the sun, still it saves on using many glass tubes.

[guffawguy]

this test is arbitrary as far as testing the efficiency of the vacuum; to do that your control should be the bottle inside the vase sealed and not sucked or other wise your only confirming that glazing is a good insulator, which the Romans knew 2,000 years ago

[chrisleblay]

yes 2000 years ago and now we have got nuclear plants instead of solar storage using vacuum. so my friend we need to share those informations because we did not evolve in the right way

[LastReplaySC]

Are there algae solar experiments around anywhere?

[GREENPOWERSCIENCE]

I actually will be doing one in a few, waiting for the panels to go on sale.

[csxconductor100]

@GREENPOWERSCIENCE hey what would happen if you use argon instead of a vacuumed atmosphere

[pinkytm1]

___ Lens air gap

_ _ mirror with hole in center airgap

___ Black surface

The light would focus on the center hole in the mirror. The air gap could be a vaccume to.

[pinkytm1]

Another difference in commercial tubes maybe the commercial tubes have a better grade of glass that allows more of the solar spectrum to be transmitted. Plus and antireflective coating. I had and idea to make a material that had micro lenes on it that would have and air gap that would allow the light to pass through a narrow hole in an mirrored surface. Then the light passes another air gap and hits a black surface. The IR light then is reflected mostly back off the mirrored surface.

[RockinPapa]

You might get a little extra kick from the vacuum bottle if foil is placed on the back half of the outer container reflecting a little more light on your bottle.

I might have to go build me one now ;-)

[db98647]

Cool!

[zws1922]

i think there will also be a temperature increase if you use air instead of vacuum. the ideea is to enclose the air, to not let it move around and up the bottle as it heats up and thus taking valuable heat from the bottle. kind of double layer window principle

[enyceckk101]

Cup noodles will be ready in uhhhhhhhhhhhhhhhh 

....... 5 hours

[tallyhoroad]

Thanks, great brain food.

[pubtor]

yeah

[bowakowa]

Nice job.

[LinuxUser269]

5 stars I think you need a another control like a darkened beer bottle the glass encasement w. no vacuum, that way you know weather there was an insulated and magnifying effect due to the glass surrounding the bottle .

[crock703]

Is this essentially what is at work in solar/steam generated electricity plants?

(I'm thinking of the kind built in the 70s -- and returning now -- where water or oil travels in a transparent tube along a curved/parabolic mirror, over a long distance, then introduced to water to turn a steam turbine.)

Do those systems vacuum-seal their tubes?

[crock703]

Hi. Extra question..

Yesterday I left a question in your last video about materials proven inflammable after wide-angle fresnel lens exposure.

I asked b/c I was curious about the use of a fresnel for heating sauna rocks - what do you think? (Foreseeable issues: getting rocks hot enough/too small fresnel exposure area/rocks not transferring heat to one another timely enough; and of course burning your sauna down by being inattentive &/or no having inflmmable protective material where need be.)

[GREENPOWERSCIENCE]

Hi,

I think you would need at least a 30x40 Spot lens and heat the rocks outside in a safe area then bring them in? Actually a mirror array might do you more good. 5 30x40 mirrors are about 3-4 KW. You could expose the heater without burning down the house:-)

The square footage of sunlight is what matters for larger things like a box of rocks. You do not get the super high heat, but it would not transfer to all the rocks unless you have a very big Fresnel lens.

Also the solar cooker idea.

[crock703]

Gotcha, thanks.

I'm not building, but curious about a off-grid solution. Electric sauna rock heaters I've seen listed are usually 3KW models - I suppose an array of mirrors could match that. B/c the rocks need to maintain a constant temp, it doesn't sound like a lens would provide an easy solution. I was hoping it'd be as simple as placing the lens in the sauna besides a large angled window.

Maybe this would just work to keep the general temp up.

[ReisendeEuropa]

To keep the sauna temperature up you could use a tin roof painted flat black. Use a small 12v solar powered fan to circulate the air. As for the rocks, nothing beats a wood heated heater. The quality of the steam is better, and it just smells wonderful. One thought on the solar would be to have a heater that is heated from the outside by a fresnell lens on a heliostat. Remember to turn the rocks to promote even heating and change the focus of the lens enough to prevent melting the rocks.

[crock703]

Can a wood burning heater be fed from within the sauna, or only outside?

I'm wondering if you could direct the hot sauna air into a colder part of the house when finished, without introducing carbon monoxide from the heater.

(Not too familiar w/ saunas, just toying with how you'd get the most out of it in an off-grid home.)

Can you get natural/passive circulation by giving the sauna a vertical circular shape and placing the heat source strategically?

[ReisendeEuropa]

I don't have much time to answer, but if you look up finnish sauna construction, you can find a lot of information. If one suggests using river rocks, don't. They can explode when heated. Use lava rocks or buy the rocks from a sauna dealer. As for the questions.. 1. Yes, 2. I'm not sure about the CO, but you would need to dehumidify the air or you will have horrible condensation problems. 3. The air circulation is aided by two holes, one near the top and one near the floor.

[crock703]

Hmn. cool. Well, thank you for your responses.

I suppose a less fussy option would be to just dump the air directly into a greenhouse.

[ReisendeEuropa]

Now there's an idea. The plants would love the water and the CO2.

[Winst0nOBoogie]

Ok, ok so we can make cheap tea,

let's get to work on important stuff, like chilling beer!

;-)

5 stars.