YSK refrigeration can be done using heat, which can then power district cooling systems.

At my grandfathers hunting cabin he showed me their fridge which has a candle sized flame at the back and thats all it needs to cool down

Because waste heat is free.

Not saying this whole idea isn’t bad, but there are plenty of processes with waste heat.

Let’s assume we need 100MWth of cooling capacity. At a CoP of 5 (generous case) we need 20MWe of power to move 100MWth (120MWth total with our electrical input converted into heat eventually as well)

Comparing that to absorber chillers: A single effect absorber at a CoP of 0.4 needs 250 MWth of heat energy at or above 90⁰C. If you go dual effect you can get 0.9-1.2, but need higher grade heat. I’ll do the worst case for now.

For reference, 250MWth is roughly what goes up the stack in a 125 MWe plant (hilariously tiny plant. Might run a remote community and be a portable turbine generator or two on a trailer? I’ve worked on gas compressors with higher nameplate capacities than that by miles)

A 1GWe coal plant at 33% efficiency burns 3GWth of heat energy and discharges 2GWth up their stack. That’s 2 GWth you have available as waste heat. By definition it has to be vented to atmosphere or to water at the condenser. That’s a lot of already-paid-for heat being literally thrown out.

If you count cooling efficiency using just thermal watts for the electric cooler:

20MWe / .33 = 60 MWth needed to generate it.

If you used a dual effect absorber at 1.2 CoP:

100MWth cooling with 83MWth of heat energy at 170⁰C.

What these two numbers show is we can move 100 MW of thermal energy with an electric chiller by burning 60MW of heat we then turn into electricity from a power plant, or 83MW of heat if we steal heat from the flue gasses and use an absorber chiller. The raw energy input to do 100MW of cooling differs by only 23 MW, so an absorber is in the same order ballpark still.

What’s important to note here is the energy needed to run an electric cooler is $money$ while the energy to run an absorber is waste heat going up the stack… These are used on earth already BTW just typically as a combined heat and power plant for universities or government/company campus. There’s no reason you can’t also apply that to an entire city.

For example, Aarhus University Hospital, Denmark uses a 3 MW absorption chiller powered by 105 °C district heating water. It consumes about 4.3 MW of heat to produce 3 MW of cooling, while simultaneously returning useful heat to the district heating network. It’s operated alongside electric chillers so the most economical option can be chosen depending on electricity prices

Crucially you don’t need to oversize your power grid for a summer heatwave peak, when your power lines are hottest (highest resistance, expand, droop lower and maybe short out on trees) so you can instead use literal waste to cool a city instead. Cooling tends to be ⅓ the amount needed for heating roughly, so you a home that needs 12kW of heating roughly needs 4kW of cooling.

2GWth of cooling capacity at 4kW per home is 500 000 homes cooled with waste heat. Of course this is assuming perfect efficiency, but it illustrates my point. District cooling typically uses 1-3% of the cooling nameplate in electrical demand for pumps afaik, so a 2GWth cooling system needs 60 MWe of pumping. To achieve the same cooling with electric chillers you need 571 MWe (assumed 3.5 CoP) just for chilling, consuming more than half of the power output of our 1GWe plant.

Because if you can find a free or cheap heat source that you’re going to vent to atmosphere up a flue, or dump into a river/lake/evaporation you can make cooling with it for almost no marginal cost once you’ve made the capital investment, plus with very little moving parts. An absorption chiller can be the last useful process on your exhaust heat before venting to the environment and all it costs is maintenance and a few small electric pumps.

You use the kiln exhaust gasses which are waste heat. You don’t need to ask the kiln to burn hotter or with more flue gas mass flow. The absorption chillers are already used in district cooling systems on university campuses and government offices. Usually where you have a combined heat and power unit, so you have your own heat source.

Theres nothing stopping you from using any viable heat source though… Plus single effect chillers run on 90°C. For waste heat that’s literally free heat why not as opposed to paying for power? Double effect chillers need 170⁰C heat for their generators, so a cement kiln could provide the heat needed to run the chillers using their exhaust gasses.

A district heating/cooling setup using low grade waste heat around ~150⁰C, plus a soapstone battery (resistively heats soapstone sand when renewables are over producing and need to either sell at any price or shut down) could provide both heating and cooling with nothing but waste heat and a thermal battery that tops up using over productive renewables.

For the same sized electric chiller, you can use 99% less electricity (you just need low pressure low velocity pumps for moving liquids around the absorption chiller) and the heat can come for free or cheap elsewhere.

Most large heat consumers try to reuse their own heat, and if they can’t they pay to discharge it into lakes, rivers, or evaporate water. If instead a district cooling company paid them for their heat they can turn a cost center into a profit center?

I’m summary, absorption chillers work on heat that’s so low temperature it’s almost useless for anything except boiler economization. That’s the value proposition.

Edit: I keep adding more to this comment as ideas flow. Sorry for the rapid edits.

I had an ammonia type fridge in my trailer I lived in, that ran off propane that was pretty great. I had 2 30lb bottles for my trailer and they would get me a month each of refrigeration and stove use for most meals. Filling a bottle cost around 30 dollars. So maybe there was more energy used compared to a compressor type fridge, but the dollar cost to run as well as convince was well worth it since our solar system was able to sustain us year round without a fridge drawing on it.