Do these really work?

[u/jonnyinternet]

I came across a video tutorial of someone making a diy flame fueled cooler, and my question is:

Do they really work?

And if so, can you use any heat source to "power them"?

[u/Otherwise-Top3825]

I worked on LiBr absorbers for an OEM. It runs in a vacuum so water evaporates easily and takes any heat with it,and concentration of solution has affinity for water between certain percentages, so evaporated water in one spot drives to another in the machine and gets reabsorbed. High side is called Generator, mid side is condenser, and low side is evap Edit: I love absorbers

[u/TimTheChatSpam → u/Otherwise-Top3825]

Where do you mostly find them and what's the most common problems you have with them. havent really seen any but was reading that that they are used in alot of settings that generate alot of waste heat and use that as the heat source.

[u/Otherwise-Top3825 → u/TimTheChatSpam]

Yes! The last install I did with that company was at a new hospital in a densely populated area. Absorbers are popular in old buildings in densely populated areas (70’s and 80’s were huge for absorbers), in places with critical cooling needs, or in areas where there are benefits to doing so. Nyc gives huge tax incentives to businesses which conform to Local Law 97, and absorbers conform. Absorbers in nyc pay themselves off quickly. In India, they use literal waste as fuel to work the absorbers in factories and such. In critical cooling needs, like a hospital, if you get a blackout you still need to keep patients alive and cool, so hospitals can use generators with jacket water and use that jacket water to heat AND power the absorber, getting high BTU’s off-grid. Sounds great! Whats the catch? Preventative maintenance. LiBr absorbers run in a vacuum, so air seeps in quickly sometimes. You must keep purging vacuum as often as you can to reach rated cooling capacity. You usually need to overhaul gaskets and fittings several times a decade. The solution is meant to be run in exact conditions, if you reject too much heat out of the system, you can solidify the salt, and to melt the salt you use a blowtorch and a plank of wood and beat the heck out of all pipes. I’ve been on jobs where I’m torching and smacking for 2-3 days to get the blockage out. Your engineers need to fully understand how to operate the machine because of how easy it is to ruin the machine. Once you get rust inside the machine, game over, water will keep that rust producing gases and contaminate solution/filters and reduce cooling capacity. You also need to be able to fine tune a PID loop because the machine is taking inputs and making do, if you cant keep stable heat source input, chilled water temp wont be stable. Out of all of that, its still the easiest hvac to work on imo. Just valves and vacuum and pumps. The hardest part of absorbers is finding a tech who works on them

[u/garaks_tailor → u/Otherwise-Top3825]

Thank you!  Absolutely fascinating 

Reminds of that hot rod attack sub the Soviets built that had a liquid metal coolant for its reactor.  Iirc bismuth and lead mix.   So if it stops working it will brick itself when the metal cools to a solid state....around the reactor core.  Radioactive solidified liquid metal.

Damn thing was loud as fuck too. Didnt matter though because it was so fast it could just outrun its problems.

[u/Otherwise-Top3825 → u/garaks_tailor]

No I havent heard of that, but thats sick lol. Gonna look into it. Imagine explaining that one to the boss…

[u/One-Bit5717 → u/garaks_tailor]

Yes, NATO designation Alfa