[0x5345414e]

So it’s a solid and it melts, absorbing heat, then it must turn back into a solid, releasing heat. I’m curious to see how they move the solid back to where it started to complete the cycle. Maybe the material doesn’t move at all, it’s on some kind of revolving assembly? It’s just that in modern refrigeration systems, the evaporator isn’t necessarily that close to the condenser, so with a solid I can see this being awkward in some situations.

[piyh]

Refrigerant pellets could be transferred like grain or wood pellets. Augurs, conveyors, or pneumatic.

If you could get it to solidify into a powder or partially solidify you could come up with alternatives, but you'd get in trouble with frozen lines.

[RandomWorker]

You have two of them or more in the assembly, you fully saturate one side, and desaturate the other. Then you switch the direction you pump. You have losses in heating and cooling the respective sides.

[moloch-hai]

The heat could be moved around via a different liquid or gas that does not need to undergo phase change.

[moloch-hai]

Adding that water and propylene glycol have been used for this in a few places, e.g. a half-billion cars.

[0x5345414e]

True, that’s pretty common in industrial and commercial settings as well. Though here I’m thinking more in terms of a residential setting. Relying on a secondary fluid loop would likely raise the cost quite a bit due to the extra components required.

They’ve raised the global warming issue about current refrigerants but what really matters is the economics of isocaloric vs. vapor compression because there are more modern refrigerants[1] that have quite low global warming potential. It makes that argument carry less weight than it used to imo.

[1] See R455A, R1234ze, R515B, for example.