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The article mentions using helium as the working gas... which there's a global shortage of. Also, Helium is an escape artist, extra thought must be given to yo
by c_o_n_v_e_x 3y ago
The article mentions using helium as the working gas... which there's a global shortage of.
Also, Helium is an escape artist, extra thought must be given to your design to prevent leaks.
- extraduder_ire 3y agoIs there a specific reason helium has to be used? These things would be amazing if nitrogen, or some other cheap gas could be used instead. I'm also wondering how heat is moved in to the unit, and out of the unit. Since normal heat pumps gain a lot from doing the compression/evaporation right where the heating/cooling is needed, but what I get from the article is that this focuses on heating water.
- chipsa 3y agoOne of the key design parameters is the thermal diffusivity of the gas. The greater it is, the deeper the stack can be, and the better it performs. Helium is about 190, while nitrogen is about 22. Next best to helium is hydrogen, but that has a bunch of other tradeoffs in terms of use. Among other things, it's very hard to seal high pressure hydrogen, and it's notably explosive in almost all concentrations with air. As for moving the heat, since it's using water as a heat medium, it just moves the water to the hot or cold spot on the internal stack to heat or cool as appropriate.
- waste_monk 3y agoGood deal on helium here if you're buying in bulk: https://news.ycombinator.com/item?id=37391584 https://news.ycombinator.com/item?id=37391584