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Home Improvement → Re: Liquid Cooled LED Bulbs

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This is a sub-selection from Liquid Cooled LED Bulbs

Lurch77 Premium Member join:2001-11-22 Green Bay, WI	Lurch77 to Jon5 Premium Member 2012-Dec-9 10:09 am to Jon5 Re: Liquid Cooled LED Bulbs That's what I was wondering. I thought it was the electronics in the base, and not the LEDs that got hot. But I may be off. Though most LED bulbs still do have requirements that they cannot be installed in any position, and cannot be inside an enclosed fixture. These bulbs claim none of that applies, install them anywhere in any position because of the better cooling system. That in itself is a nice if it really pans out. Not to mention the bulbs actually look decent. said by Kramer: Yes, we have been anxiously awaiting the Switch bulb here in a few threads. At 47 dollars ea. for a 60 watt bulb, my anxiousness has subsided into quicksand but not because I can buy them now. The bulb might not be over-engineered, but it is way over-priced. Yes cooling is a major issue, but other manufacturers have handled it with massive heat-sinks and they have been able to deliver a bulb at a much lower cost with similar claims of longevity. Switch knows they will not sell more then a handful of these at this price and is working to lower costs. I just don't see any of these catching on until the price point gets near 5 dollars. That's a few years away. The only problem with big heat sinks is they are ugly. We have an LED over our kitchen sink. It is hidden from direct sight. It is one ugly bulb, one that I would not want to install in our decorative bathroom fixtures or in our outdoor sconces, where the bulbs are in full sight.
	actions · 2012-Dec-9 10:09 am ·
Kramer Mod join:2000-08-03 Richmond, VA	Kramer Mod 2012-Dec-9 10:38 am I agree the Switch bulbs are beautiful. The light is supposedly very pleasing too. I use CFLs that cost about a buck a piece in places where I don't care about how the bulb looks or the color of the light. I use standard incandescent bulbs in a few places where lighting color and appearance is important to me. I have few LEDs scattered around the house when I was able to buy them for around ten bucks. I am going to keep buying the CFLs and incandescents until the price of decent LED bulbs come to Earth. There is virtually no energy savings to an LED (at this point) compared to a CFL. LEDs may have a slight environmental advantage. I have one fixture where I would be willing to pay $20-30 per bulb for a decent LED. I have a fixture that hangs at almost eye height over my kitchen island. It has clear shades. I currently use 2- 150 watt clear bulbs on a dimmer. The bulbs are often dimmed and the ringing drives me crazy. I often run them full-blast just to avoid hearing the ringing. They cost about 3 cents an hour to run, which is pretty expensive if they are left on 8 hours a day. That works out to about $7.50/ month to have two light bulbs lighting my kitchen counter. LED would be a perfect application, but as of yet Switch hasn't released their 100 watt equivalent bulb and even when they do, they haven't been able to get the color temperature and spectrum close on that bulb to what they have been able to achieve with their 60 watt. A dimm-able 150 watt isn't even on the horizon.
	actions · 2012-Dec-9 10:38 am ·
tschmidt MVM join:2000-11-12 Milford, NH ·Consolidated Com.. ·Republic Wireless ·Hollis Hosting	tschmidt to Lurch77 MVM 2012-Dec-9 10:51 am to Lurch77 said by Lurch77: That's what I was wondering. I thought it was the electronics in the base, and not the LEDs that got hot. But I may be off. Though most LED bulbs still do have requirements that they cannot be installed in any position, and cannot be inside an enclosed fixture. These bulbs claim none of that applies, install them anywhere in any position because of the better cooling system. That in itself is a nice if it really pans out. SparkChaser is our resident opto expert so should be able to provide the definitive answer. Here is my uninformed take. The LED control circuit is basically a switching power supply. It is pretty efficient. My guess is most of the circuity is located on the back of the multi-LED substrate. The bulk of wasted power is the LEDs themselves, not the control circuit. Liquid cooling is a clever idea, liquid is a much better thermal conductor then air. That being said I assume cooling is a thermosiphon loop. Assuming the bulb is in upright position hot LEDs are at the bottom. That warms the fluid causing it to rise and cool off through radiative and conductive cooling and sink back down. I don't understand how that works if the bulb is in any other then the normal upright position. Unless it is just a matter the fluid's better thermal conductivity keeping the LEDs as safe operating temperature due to turbulence caused by temperature differences. In order to operate in any location there has to be enough fluid in the bulb to always keep the LEDs immersed. At $60 a pop they are out of my price range but I'm excited about the advancement in LED lighting. /tom
	actions · 2012-Dec-9 10:51 am ·
disconnected @snet.net	disconnected Anon 2012-Dec-9 4:22 pm I had my first E27-based LED lamp, a Utilitech from Lowe's, fail on me last month.
	actions · 2012-Dec-9 4:22 pm ·

tmh @comcastbusiness.net	tmh to tschmidt Anon 2012-Dec-10 6:45 pm to tschmidt said by tschmidt: Liquid cooling is a clever idea, liquid is a much better thermal conductor then air. That's true, but in this case liquid is an intermediate transfer medium. The liquid must transfer its heat to air, otherwise it will get hotter. I don't see any difference in bulb design to improve that. So heat transfer to the environment is no more efficient than before. In fact, it is less so. The liquid is at a lower temperature and so would need a greater surface to effect the same heat loss. Seems like snake oil to me.
	actions · 2012-Dec-10 6:45 pm ·
Raphion join:2000-10-14 Samsara	Raphion Member 2012-Dec-10 9:05 pm said by tmh : said by tschmidt: Liquid cooling is a clever idea, liquid is a much better thermal conductor then air. That's true, but in this case liquid is an intermediate transfer medium. The liquid must transfer its heat to air, otherwise it will get hotter. I don't see any difference in bulb design to improve that. So heat transfer to the environment is no more efficient than before. In fact, it is less so. The liquid is at a lower temperature and so would need a greater surface to effect the same heat loss. Seems like snake oil to me. This is how large transformers have been cooled for more than half a century, minus the see through casing. If it's snake oil, it must be some pretty good snake oil.
	actions · 2012-Dec-10 9:05 pm ·
tschmidt MVM join:2000-11-12 Milford, NH ·Consolidated Com.. ·Republic Wireless ·Hollis Hosting	tschmidt to tmh MVM 2012-Dec-10 9:09 pm to tmh said by tmh : Seems like snake oil to me. Why do you say that? A fluid carries heat away from the die very effectively. The exterior of the bulb has a large surface area allowing heat to radiate and conduct away. /tom
	actions · 2012-Dec-10 9:09 pm ·

tmh @verizon.net	tmh Anon 2012-Dec-10 9:42 pm said by tschmidt: said by tmh : Seems like snake oil to me. Why do you say that? A fluid carries heat away from the die very effectively. The exterior of the bulb has a large surface area allowing heat to radiate and conduct away. /tom It is difficult to see from bulb, but the added surface doesn't appear to be very significant. For example, water cooled CPUs have radiators with an enormous heat transfer surface, plus forced air cooling to boot. I don't see any similar benefit to simply filling the globe with liquid.
	actions · 2012-Dec-10 9:42 pm ·
TheMG Premium Member join:2007-09-04 Canada MikroTik RB450G Cisco DPC3008 Cisco SPA112	TheMG Premium Member 2012-Dec-10 10:01 pm said by tmh : It is difficult to see from bulb, but the added surface doesn't appear to be very significant. For example, water cooled CPUs have radiators with an enormous heat transfer surface, plus forced air cooling to boot. I don't see any similar benefit to simply filling the globe with liquid. The added surface area is quite significant. In most LED bulbs, it is only the metal base which acts as the heat sink. The outer lens/cover/bulb does not contribute to cooling at all, since it is filled with air, which is a pretty good insulator. Filling the inside of the clear bulb with liquid allows heat to be conducted to and therefore dissipated through the outer clear bulb. Also, CPUs generate several times more heat than an LED bulb. The type of CPU that PC enthusiasts watercool with radiators typically dissipate in excess of 100W. Quite often, video cards are also cooled in the same loop and the same radiator, meaning anywhere from 200W to as much as 800W may need to be dissipated, depending on the system.
	actions · 2012-Dec-10 10:01 pm ·
alkizmo join:2007-06-25 Pierrefonds, QC	alkizmo Member 2012-Dec-10 10:03 pm Can't we all agree that a LED bulb shouldn't need to be water cooled?
	actions · 2012-Dec-10 10:03 pm ·
leibold MVM join:2002-07-09 Sunnyvale, CA Netgear CG3000DCR ZyXEL P-663HN-51	leibold MVM 2012-Dec-10 10:26 pm I don't think so. Doesn't it make sense to expect a longer useful life from a water cooled LED bulb then a cheaper LED bulb based on the same LEDs (same power) without the added cooling ? It is heat that kills electronics (both LEDs and their power supply / driver circuits). I do not expect cheap LED bulbs to perform to expectations and we are already hearing the first reports of early death of LED bulbs. The only reason for me to be skeptical about these bulbs is that mechanical business of the expansion cylinder. Is this really going to stay sealed over years of in/out motion ? What happens if the bulb starts to loose fluid ? Does the water end up where it is most likely to cause the biggest harm (power supply) ?
	actions · 2012-Dec-10 10:26 pm ·
Lurch77 Premium Member join:2001-11-22 Green Bay, WI 1 recommendation	Lurch77 Premium Member 2012-Dec-10 10:57 pm It's not water. It's liquid silicone. Your point about losing material is valid, but it most likely won't bother the electronics. Potted electrical components are surrounded by silicone.
	actions · 2012-Dec-10 10:57 pm ·
SparkChaser Premium Member join:2000-06-06 Downingtown, PA 1 recommendation	SparkChaser to leibold Premium Member 2012-Dec-11 7:08 am to leibold it's full of liquid silicone, which dissipates heat from the 10 LEDs (12 LEDs for the 100-watt version). Warmer silicone moves toward the glass exterior, where heat dissipates into the air; as it cools, the silicone drops back toward the bulb's heart. Think of a lava lamp this works basically the same way, said Dave Horn, chief technology officer at SWITCH. You just can't see the gloopy circulation. »www.switchlightingco.com ··· lqd.html I have to go turn on my Lava Lamp (yes, I do have one )
	actions · 2012-Dec-11 7:08 am ·
alkizmo join:2007-06-25 Pierrefonds, QC	alkizmo Member 2012-Dec-11 7:15 am said by SparkChaser: Think of a lava lamp this works basically the same way, said Dave Horn, chief technology officer at SWITCH. And lava lamps don't work upside down.
	actions · 2012-Dec-11 7:15 am ·
SparkChaser Premium Member join:2000-06-06 Downingtown, PA 1 recommendation	SparkChaser Premium Member 2012-Dec-11 7:17 am said by alkizmo: And lava lamps don't work upside down. but.... the heat source is in the center of this lamp and the bottom of the lava lamp.
	actions · 2012-Dec-11 7:17 am ·
alkizmo join:2007-06-25 Pierrefonds, QC	alkizmo Member 2012-Dec-11 7:19 am said by SparkChaser but.... the heat source is in the center of this lamp and the bottom of the lava lamp. Satisfying explanation. Thnx
	actions · 2012-Dec-11 7:19 am ·
public join:2002-01-19 Santa Clara, CA	public to tschmidt Member 2012-Dec-14 6:24 pm to tschmidt said by tschmidt: The LED control circuit is basically a switching power supply. It is pretty efficient. My guess is most of the circuity is located on the back of the multi-LED substrate. The bulk of wasted power is the LEDs themselves, not the control circuit. LED die material in not compatible with silicon integration. The driver in consumer grade bulbs is a discrete component pcb in the base. LEDs are about 40% efficient, and heat must be removed from very small volume. A light weight cooling can either use heat pipes, or ultrasonic spray cooling to transport heat to the heatsink, Liquid immersion is rather crude.
	actions · 2012-Dec-14 6:24 pm ·

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This is a sub-selection from Liquid Cooled LED Bulbs