I really want affordable dip and dots at home, and to do some cryogenic experiments that are only possible using liquid nitrogen or liquid helium.
Also those Dewar's arnt cheap, nor are the pumps
FWIW, lots of these steel cups that are popular these days are vacuum flasks and cost practically nothing.
Homemade Liquid Nitrogen Generator - https://news.ycombinator.com/item?id=23828316 - July 2020 (67 comments)
Applied Science is fantastic channel if you haven't seen it. He's also on HN.
OP's design is much more impressive and hard to build than using a Stirling cryocooler like I did.
Liquefied air is a potentially interesting mode of energy storage for islanded solar because it doesn't require high pressure storage (which has safety concerns)-- for that application the round trip efficiency isn't critical as there is nothing else to do with the power... but it can't be a total joke. And the basic JT cycle is really poor. I understand that simply adding an expander and another heat exchange stage can improve it a lot.
As far as 'closed loop' sadly that does break the economics, I think-- part of the reason why cryogenic nitrogen storage is interesting is because the nitrogen expands 800 fold at atmospheric pressure, so the container for the decompressed nitrogen would be gigantic.
They look like legit AdSense ads, and there's a "liquidnitrogen" comment on one of the related scripts.
