@whitequark@social.treehouse.systems Alright, I've been thinking about it (never a good idea), and here's an attempt at that argument. Note that I'm not an expert on industrial revolution history or any of the technologies I'm about to discuss, so… y'know.
Of all the inventions of the industrial era, the vapor-cycle heat pump was the closest to optimal at its inception and has remained essentially unchanged to the present day, *and* is a completely essential technology to modern life. It's probably not the most *foundational* invention (the steam engine probably takes that crown), but I assert that it is the *greatest*.
For example, the steam engine is a dead technology today.
Or for another example, consider the piston-driven internal combustion engine. Foundational, yes, and ubiquitous in the modern day; but thermodynamically, it's just fundamentally inefficient. We've milked damn near every possible joule of heat recovery out of it, but the only thing it's really good at is low-power efficiency; for essentially every other purpose, the gas turbine is superior. In contrast, *nothing* is superior to the vapor-cycle heat pump at pumping heat.
(The gas turbine, an incredibly simple and effective technology which in its most basic form has *one moving part*, is another contender for greatest invention, but… the externalities of combustion are inescapable.)
So yeah. The refrigerator emerged in the mid-1800s and is essentially unchanged since. Advances in chemistry have greatly improved refrigerants, but the basic structure is still a compressor, condenser, and evaporator all in a loop. It's effective, efficient, free of inherent externalities (the nastiness of fluorocarbons aside, in correct operation they're not *supposed* to leak refrigerant, and simple propane actually works perfectly fine), and *massively* impactful to modern life. (Just think how much of our food is utterly reliant on refrigeration, and we don't even think about it.)
