Liquid Cooling. Will we ever see it incorporated into flashlights?

[DayofReckoning]

Coming from a background in overclocking computer components (CPU's,GPU's, RAM), I'm quite familiar with the massive benefits that liquid cooling components can provide, whether that be with a closed loop system with pump and radiator, or custom loop system with reservoir, versus a traditional passive or air cooling configuration.

One could argue that we are at a point now where a passive heatsink, in this case, that being the flashlight body and head, isn't capable of handling the incredible output that LED's are outputting, proof of this being the immediate output stepdown we see in virtually every high end lumen pusher that is released. We can easily make 100,000 lumens, it's the heat that's the issue. A liquid cooling solution would allow manufacturers to push the envelope even further.

Imalent has incorporated some small PC fans into some of their lights, but (1.) Performance is significantly lower than the theoretical performance of a small CLC pump/radiator (2.) Fan operation is very loud, whereas a CLC could provide silent cooling.

"Reliability" "Complexity" "Cost" etc. I'm certain these are some of the key issues that will be brought up as to WHY it's not being done. And rightfully so, it wouldn't the easiest thing to build.

But at the same time, I believe that if a manufacturer was willing to get innovative and think outside the box, I really believe it could be done.

The question is, do you think that we will see it at some point in the future?

 

[RedLED]

Yes we will see it.

 

[idleprocess]

Some designs use fans and I suspect that some have used heat pipes to better distribute the heat throughout a thermal mass, but I'm not sure that actively circulating coolant is profitable in engineering terms for small battery-powered portable devices that sink to air.

 

[LedTed]

Yes, yes we do. A couple of the Imalent MS18s use such a system.

 

[Fish 14]

Check out Matt Smith, he has a liquid cooled flashlight

 

[idleprocess]

Yes, yes we do. A couple of the Imalent MS18s use such a system.

Per Imalent's own literature that's a heat pipe, which is clever a form of phase change cooling.

Built-in heat pipe radiator with excellent heat dissipation, and equipped with an inlet and outlet fan silent,waterproof,heavy wind , which is a perfect combination of great energy and technology.

The diagram in the feature image bears a strong resemblance to a number of CPU coolers that use heat pipes to move the heat more efficiently from the source to the radiator and forced-air cooling.

 

[Spin]

Interesting concepts. During my ham radio days transformer or mineral oil is/was used as a coolant.

 

[DayofReckoning]

Heat will only continue to rise, as manufacturers will continue to push the envelope. I truly think we are at the literal brink of what passive cooling will allow. We see this with Imalent and Acebeam (X70) using fans in their designs, with results that, IMO, are less than impressive. Some of these lights are near the melting point.

Heatsinks, heatpipes, and fans are only going to get you so far. We see this in CPU cooling. Enormous, massive heatsinks equipped with heatpipes and push pulls fans, cannot effectively cool the highest end CPU's when clocked at their highest frequencies as well as the best AIO cooling solutions.

Good air cooled solutions are more [FONT=Verdana,Arial,Tahoma,Calibri,Geneva,sans-serif]feasible right now, and I do hope we see more of these in upcoming monster output lights. Noise is the biggest con with that solution right now, though I'm sure they could take a few tips from some of the PC fan manufacturers who have perfected silent cooling. The industrial grade server fans Imalent uses are probably not ideal. [/FONT]

We are at the 100,000 lumen mark right now. It will be interesting to see how things play out once we get to the 500,000 to 1M mark.

 

[idleprocess]

Heat will only continue to rise, as manufacturers will continue to push the envelope. I truly think we are at the literal brink of what passive cooling will allow. We see this with Imalent and Acebeam (X70) using fans in their designs, with results that, IMO, are less than impressive. Some of these lights are near the melting point.

Indeed some of these are at the limits for passive cooling. It's a rare modern LED flashlight capable of 1000+ lumens output in a 1x18650 form-factor that doesn't have active thermal management to keep temperatures - LED, driver, even battery compartment - within safe ranges.

Heatsinks, heatpipes, and fans are only going to get you so far. We see this in CPU cooling. Enormous, massive heatsinks equipped with heatpipes and push pulls fans, cannot effectively cool the highest end CPU's when clocked at their highest frequencies as well as the best AIO cooling solutions.

Good air cooled solutions are more [FONT=Verdana,Arial,Tahoma,Calibri,Geneva,sans-serif]feasible right now, and I do hope we see more of these in upcoming monster output lights. Noise is the biggest con with that solution right now, though I'm sure they could take a few tips from some of the PC fan manufacturers who have perfected silent cooling. The industrial grade server fans Imalent uses are probably not ideal.

We are at the 100,000 lumen mark right now. It will be interesting to see how things play out once we get to the 500,000 to 1M mark.

I feel the reason we haven't seen too many attempts at active thermal management in flashlights as opposed to computers is due to fundamental design differences between the two. The two key factors I see are that flashlights are size-constrained and expected to be nominally waterproof/airtight. A computer - especially a desktop - can dedicate considerable volume to heat management apparatus and have sufficient radiating surface area to dump a goodly amount of heat. A flashlight, necessitating an almost entirely enclosed design while remaining small enough to be handy will see relatively little benefit to active thermal management.

The stock CPU HSF on my desktop likely has square feet of area on its radiator and a ~4" diameter fan in close proximity. A convenient flashlight cannot hope to match this and remain pocketable or even as handy as its contemporaries relying on more passive cooling.

Have there been liquid-cooled flashlights? Sure. There are a number of homebrew spotlight-sized units out there using liquid cooling which are ... unwieldy. The only other example that comes to mind is the flying searchlight (build photos unfortunately seem to be missing but the videos are indeed illuminating) which was a unique case - by nature of its application it got tremendous airflow for free.

 

[DayofReckoning]

Indeed some of these are at the limits for passive cooling. It's a rare modern LED flashlight capable of 1000+ lumens output in a 1x18650 form-factor that doesn't have active thermal management to keep temperatures - LED, driver, even battery compartment - within safe ranges.



I feel the reason we haven't seen too many attempts at active thermal management in flashlights as opposed to computers is due to fundamental design differences between the two. The two key factors I see are that flashlights are size-constrained and expected to be nominally waterproof/airtight. A computer - especially a desktop - can dedicate considerable volume to heat management apparatus and have sufficient radiating surface area to dump a goodly amount of heat. A flashlight, necessitating an almost entirely enclosed design while remaining small enough to be handy will see relatively little benefit to active thermal management.

The stock CPU HSF on my desktop likely has square feet of area on its radiator and a ~4" diameter fan in close proximity. A convenient flashlight cannot hope to match this and remain pocketable or even as handy as its contemporaries relying on more passive cooling.

Have there been liquid-cooled flashlights? Sure. There are a number of homebrew spotlight-sized units out there using liquid cooling which are ... unwieldy. The only other example that comes to mind is the flying searchlight (build photos unfortunately seem to be missing but the videos are indeed illuminating) which was a unique case - by nature of its application it got tremendous airflow for free.

Good points. One thing I think should be emphasized is that the discussion is really about the giant, monster, record breaking lights we see coming out each year, when the extra size, weight and bulk of a water-cooling solution is negated a bit. Water cooling will obviously never be practical for smaller/mid sized lights.

Not being an engineer or flashlight craftsman, I have no idea how feasible this may be, but the image I see in my mind of how a configuration could be implemented, and have some level of ruggedness and reliability, is something that looks like a Maxabeam, where we have a small box on the bottom side, only in this case instead of a battery pack it would instead contain a 120mm or 240mm PC style AIO radiator and fan, enclosed and sealed up.

 

[idleprocess]

Good points. One thing I think should be emphasized is that the discussion is really about the giant, monster, record breaking lights we see coming out each year, when the extra size, weight and bulk of a water-cooling solution is negated a bit. Water cooling will obviously never be practical for smaller/mid sized lights.

That's certainly where the potential lies - especially once one enters the "portable searchlight" domain. Come to think of it I recall reading about a build on BLF that used liquid cooling to circulate coolant through copper pipe around the perimeter of the interior of the body. The thing was enormous - looks to be a cylinder roughly 12" in diameter and 6" deep.

Not being an engineer or flashlight craftsman, I have no idea how feasible this may be, but the image I see in my mind of how a configuration could be implemented, and have some level of ruggedness and reliability, is something that looks like a Maxabeam, where we have a small box on the bottom side, only in this case instead of a battery pack it would instead contain a 120mm or 240mm PC style AIO radiator and fan, enclosed and sealed up.

That's also an amenable form-factor - not expected to be especially handy, an enormous battery pack with watt-hours to spare, and the possibility of dedicating space to thermal management. A reasonable set of parameters for am extreme thrower or floodlamp - especially in the role of something vehicle mounted.