» Electronics » LEDs »Liquid radiator for LED: how, why, why (part 1 of 2)

Liquid radiator for LED: how, why, why (part 1 of 2)




The fact that they once came up with an incandescent lamp is also good, but now it is gradually losing its popularity as the "right" device for electric lighting. After all, an incandescent lamp heats up 95%, while it shines only 5%. Another thing is the LEDs, which on the contrary shine at 95%, although the drop in the price of LED lamps is not always so big. Here, someone would become a trillionder if the Sun suddenly disappeared.

Outdoor lighting (parking, road) usually requires a large brightness of LEDs, and the use of metal radiators is not always economically justified, and the diode on the street should still be inserted into the glass and aluminum housing to protect it from rain.
So what is a liquid radiator, one asks.

The fact is that the LED, like any semiconductor that is under load (high current and voltage on it) is heated. Sometimes such heating leads to its failure. In this case, metal heat sinks (radiators) are used, which are blown by running air. The disadvantage of this design of the radiator may be its bulkiness. You can compare with a car in which instead of an anti-freeze engine cooling system are air-cooled radiators (the size of an airplane’s wings).

There are also disadvantages of metal radiators: a large amount of space, holes in the body of the device for cooling (where dust or insects then fall), more weight, the use of special heat-conducting pastes or adhesives for better heat transfer to the radiator, empty heating of the surrounding space, so water cooling has some advantages .

As I researched, you can cool the LED by loading it directly into water (cold or room temperature). In this case, there is no need for paste, a radiator, and when in transparent water and a vessel, the LED will give out light no worse than in air, and you can take running water and, if necessary, use warm water for needs.

Ideally, I recommend: apply distilled or bidistilled water (it almost does not conduct electric current), connect low-voltage LEDs (an intense electrolysis process with gas evolution takes place at high voltage), serious waterproofing of the contacts in the water is needed.

The use of alternating current reduces the process of gas evolution, but the diode flickers very much - here it also depends on the frequency of the current. Flickering of light with a frequency of more than 30 Hz is almost not perceived by the human eye (which is successfully used in cinema and on television).
  
To set up an experiment, you need a minimum of materials and tools.

Tools and devices:

- multimeter (measure current up to 2 A);
- thermometer 100 degrees (optional);
- a glass (glass, transparent);
- 12-volt battery (or 12-volt power supply, rated at 20 watts or more).





Expendable materials:

- distilled water (200 ml);
- waterproof glue (15 g, or rosin solution);
- solution of brilliant green (15 ml);
- connecting wires;
- "Crocodiles" (6 pcs.);
- variable resistor (at 20 W, range 0-68 Ohms);
- white LED (12 V, 10 W);
- solder;
- rosin.






Stage 1.
We begin the study by soldering the wires to the LED, when the solder cools down, we well coat the open contacts of the soldering surface with waterproof glue (or rosin):



Stage 2.
Pour into a glass of distilled water, about 200 g:



Stage 3.
After the waterproofing glue dries, we load the LED on the bottom of the glass so that its own radiator is on top and the light-emitting surface rests on the bottom of the glass:



Stage 4.
We put the resistor at the highest resistance and turn on the power, depending on the current value, we adjust the power of the LED glow with the help of a resistor. If gas is not released (means reliable waterproofing of contacts in water):



Stage 5.
We observe a change in water temperature depending on the magnitude of the current. For interest, you can measure the temperature of the water in the glass with a thermometer, it captures the "non-critical" temperature near the diode and we see the real cooling effect (the larger the volume of water, the faster the LED will cool down). Here, part of the heat comes out on top of the glass and is also given to its walls:




Stage 6.
Add a little green water (about 0.5 ml) to a glass of water (200 ml), the liquid turns emerald color, by connecting an LED we observe a pleasant light green light. Iodine also gives color, but the iodine solution has less electrical resistance than zelenka. Do not forget also that green is very difficult to remove, so try not to stain it with anything superfluous:




Light can be of different colors, not only from a colored solution, but also from the colored glass of the vessel into which the diode is immersed.
Instead of water, it is permissible to use other liquids: clear oil, glycerin. Different liquids - different speeds of heating the glass.
For example, glycerin can be used instead of water, but its thermal conductivity is 2 times lower than that of water, while glycerin is an insulator, it does not badly protect contacts from corrosion, and can be easily washed off with water if necessary:

The advantages of transparent oil are also that it does not conduct current, protects contacts from corrosion, and also evaporates very slowly, although as disadvantages: the thermal conductivity of the oil is 5 times less than water, therefore there is a greater risk of overheating of the LED, the difficulty of washing off the fat.

In the next article, I will look at a practical liquid-cooled version with immersion for a floodlight.

Experience video:

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8.8
8.6

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27 comments
I can’t say anything categorically, but it seems to me that the projection of frames from a film (inter-frame intervals) by a movie camera onto the cinema’s white screen and video playback from a computer on the monitor screen (the frame rate generated by the video card and played back by the monitor, afterglow) are somewhat different concepts, although it may I'm wrong.
brilliant!
Modern video cameras have 25 or 50 fps. High-speed cameras with fps 500 and higher are used in video surveillance systems or in scientific laboratories.
The regular Sony Vegas video editor cannot edit high-speed video.The maximum that he is capable of is 60 fps.
I do not know what should be the minimum frame duration so that the eye does not fix the "extra frame".
Here are the specifications of the fps video editor and 50 fps video. The frame duration is 20 ms, and the eye sees an "extra frame".


[media = https: //www.youtube.com/watch? v = 0gBVeHPxt8k]
Author
Nruter for film and television standards a frame duration of 0.04 s.
But modern cameras do for example 240 frames per second (frame length 0.004 s). And I say, measure on your video editor (can’t this be done on the video editor):
- What is the minimum frame duration in seconds, so that a person cannot notice it, as an obstacle when watching a video ...
New Standard,
The frame duration cannot be less than 0.04 seconds. Therefore, you can insert a frame only of such a duration. About everything else I wrote above.
Author
send your favorite car to the orbit of Mars ... not by February 14th it will be said ...
Author
Nruter, I am aware of about 25 frames ... Here it’s not that ... you prove that frame 25 when you insert another image there, you can still see it (flickers, makes it difficult to see), that is, the frame length of 0.04 s is still visible ... And I ask, what should be its length (obviously less than 0.04 s) for a person to notice him (frame)? ... I wrote 30 Hz (0.03 s), someone can say less ... so that's how much. .. (you can insert a black square, so you can see better) ...
Frame rate - 25 per second. Therefore, one frame lasts 1/25 sec. Or 0.04 sec. Or 40 ms. This is the minimum frame duration for Europe. In America, television shows 29.97 frames per second. There is a minimum duration of about 30 ms. There is high-speed shooting at a speed of 200, 500 and even up to 2500 frames per second. This is for shooting experiments, so that later, in slow motion, you can see, for example, the flapping of the wings of a bee or the flight of a bullet. Basically, this speed is used for scientific purposes. The equipment costs a lot of money.
The frames in the video sequence are in this sequence - 0, 1, 2 ...... 24. A total of 25. As soon as the 25th frame ends, a 1 second countdown appears on the timeline. Next is 1 second and the next frames up to the second second.
Author
Nruter, you’re cunning, you want us to get some kind of advertising on frame 25)) ... Once you have opened the video editor ... then experiment and report back to us ... at what duration of a random frame a person does not notice it ... you can just black square insert ...
And why is he in the second picture at number 24? or am I not looking right?
Quote: New Standard
I meant that above 30 Hz a person goes astray

Well, yes, and up to 30 Hz it can easily be counted. )))
pogranec,
Does not depend. Here the author decided a little wrong with the concepts
it’s more than 25 frames per second to change pictures (in a movie) and we don’t notice a random frame (a completely different picture).

At a repetition rate of 24 images per second or more, the eyes cease to perceive an ordered sequence in the form of separate images. After all, we see the change of scenes in the cinema :).
And here is the promise.




[media = https: //www.youtube.com/watch? v = rXF8D_RYy8o]
And it does not depend on the technical device from which you are viewing? It seems to me the difference between CRT and modern TVs should affect this. In general, as the TV showed in the 80s, so there probably and 26 frames could be inserted and no one would have noticed-)))
Just do not tell tales about the 25th frame. Do you want me to make a short video and insert every 25th frame just a picture and show it here? I want to warn you right away that contrary to the generally accepted opinion, this frame will flicker, it is clearly visible and it interferes with viewing the main video.
Author
here I meant that above 30 Hz a person goes astray ...how many times per second the lamp blinks ...)) I do not argue, it’s still not nice - the blinking light, there you need high frequencies, frames 100-150 per second. ..more than 25 frames per second change the picture (in the movie) and we don’t notice a random frame (a completely different image). Once in the USA they conducted an experiment - they inserted advertising in movie theaters into frame 25 ... people then actively (subconsciously) bought "item 25 frames" ...
well, spirit stink so stink ...))

About whiteness, I once watched the program "What? Where? When?" So there the "scientists" said, they say, it scatters the light. I rummaged through the entire Internet, but did not find this. Maybe Ivan is right ..
Author
Dmitrij just remembered how he came to the store, I ask ... do you have turpentine? .. the seller answers ... (here in the original language) - "It’s ours of you skipidar ... win stink ... vіzmіt lіpsche whit-spіrіt ... For me whit-spіrіt stink, I say ...")). I have not tried whiteness, but thanks for the idea. With milk (or some muddy liquids) I know it’s cool dispersing ... it's like a dull lamp ...
LEDs that on the contrary shine at 95%,
- You have an overly optimistic view of the effectiveness of LEDs, not supported by objective data.
Flickering of light with a frequency of more than 30 Hz is almost not perceived by the human eye
Another misconception: both 50 Hz and, to a lesser extent, 100 Hz are perceived by a person, otherwise two-half-wave rectification would be used in LED lamps and would not bother with its filtering. And so you do not argue with this - turn on the usual LON through a diode and admire it.
you write that 5% goes into heat.

this is a figure far from reality. in reality it is 50-60%.

therefore, it is already problematic to use LEDs for example in the automotive industry, etc.
"Whiteness" is not added for this, but so that the water from the algae does not turn green.
Quote: Dmitrij
Water with bleach


You can’t make a hole in the roof, it's a diversion
Quote: Dmitrij
Water with bleach


Vodka with bleach. Mendeleev did not even know about it.
Water with bleach

Tesla launched yesterday to Mars found in Dagestan with broken numbers
There are some advantages, but there are also disadvantages: increased requirements for waterproofing contacts, the need for periodic maintenance, and in our climate when using water, it can not be used outdoors.
pour whiteness there .. somehow I saw, so do the “bulbs”. "White" strongly scatters the light, the lamp should burn like a torch.

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Hand it for the smartphone ...