Absorption coolers use heat to regenerate their refrigerant. Two common types are a water vapour-LiBr chiller, and an ammonia-water chiller (in fact Einstein patented a mini bar chiller design still used today that has no moving parts, using just helium or hydrogen and gas absorption/evaporation to move refrigerating gasses around)

Single effect chillers have a low Coefficient of Performance (CoP) roughly around 0.4-0.6, meaning for every watt of heat you apply to a single effect chillers, you move 0.4-0.6W of heat, but they only need a minimum of 90⁰C in heat to power them.

Double effect chillers can reach 0.9-1.2 CoP.

Flue gasses are typically hotter than 90⁰C, so you’ll often see absorbers part of combined heat and power systems. Cooling in the summer, heating in the winter. All using waste heat from power generation.

What I find the most fascinating about them is they work using heat. The only power you need to apply is for a few pumps to move fluids around at low pressures, otherwise the primary refrigeration energy comes from heat regenerating the refrigerant.

I’ve often wondered what a district cooling system using these would get for efficiency if you colocated it with something energy hungry like a cement kiln or glass kiln.

Video of how a double effect chillers works

District cooling video

Edit: these are used already for district cooling, just usually for a campus like a university or government complex. The big benefit is you can run them on marginal heat sources, even off of low grade geothermal.

  • AngryCommieKender@lemmy.world
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    3 days ago

    There is currently so much waste heat produced by energy production and industrial processes, that for most of what the OP is talking about, the heat may as well be “free” since it was waste heat that has to be vented. Waste heat needs to be used to mitigate climate change, because waste heat is going to become an issue sooner than later.