4 ms·
To try and understand it I just skipped through this lecture: https://www.youtube.com/watch?v=-d4NAEPZrbg https://www.youtube.com/watch?v=-d4NAEPZrbg To a lay
by tinco 3y ago
To try and understand it I just skipped through this lecture:
https://www.youtube.com/watch?v=-d4NAEPZrbg https://www.youtube.com/watch?v=-d4NAEPZrbg
To a layman like me, the most interesting bits start at: 6:14 and 37:36. If you're interested in the materials (they're perovskite crystals) it's at 22:45.
My explanation as a total layman: There are materials that when you apply an electric field to them they almost immediately heat up. Then as you keep the field on them they cool down again naturally, and if you then remove the electric field they cool down quickly. So you with electric fields you can make the material do a pretty wild temperature swing.
Then the next trick is to extract that temperature differential from the device. You could imagine a container with a fluid and the device in the middle, a hot side on the right and a cold side on the left. As you push fluid to the right you heat up the device, and as you push fluid to the left you cool down the device. This will over time sort of ratchet the both sides to greater extremes. Even simpler they also made a "slapper" which simply puts the device on a little motor actuated arm, and it slaps the device to a load whenever its cool, and then to another load when it's hot.
Other (to me) cool detail is that they got Murata to manufacture these devices as MLC's, so it's just your typical Murata MLC capacitors but with these electrocaloric material layers.
edit: also at 44:00 he shows a slide comparing this technology to others, and it shows that even though it's more efficient than vapor compression it's less efficient than acoustic, although they're both very efficient. So I guess the big question is going to be is if this is going to be more practical/economical. From what I've heard there's a bunch of companies already moving forward with manufacturing thermo acoustic heat pumps so those are definitely further along.
- londons_explore 3y ago> more efficient than vapor compression This has a lot of asterisks around... Vapor compression has 100% of the theoretical (ie. carnot efficiency), as long as you use the correct type of compressor (ie. isothermal) and use an isothermal expander instead of a capillary tube. Unfortunately, isothermal compressors don't exist, however approximating one with a multi-stage regular (ie. Adiabatic) compressors interleaved with radiators gets pretty close to it. Turns out that in current systems, the extra piping and complexity isn't worth it. But when energy is expensive (if people start taking carbon emissions seriously) and manufacturing is cheap (due to all the parts being mass produced), it becomes worth it.
- LoganDark 3y agoit becomes worth it when the heat pump makes it so that i can live in my house without getting heat stroke and dying :)
- guerrilla 3y agoOr die of starvation because all income is going to winter heating bills!
- LoganDark 3y agoactually, the reason why I need an air conditioner so badly is because my body naturally generates enough heat that I don't need a heater in winter. I also usually don't need a coat in below-freezing temperatures unless I'll be out there for longer than 30 minutes. Commonly-accepted indoor temperatures of 70-78F are far too warm for me, I need closer to 60F, ideally below. I have to open up and modify my air conditioners so that they won't shut off near those temperatures, because from the factory they will refuse to make the room cool enough.
- Dylan16807 3y agoThey're talking about whether it's worth it to go multi-stage, not to have the device at all.
- lalalandland 3y agoThe curve figures he show in video at 14:03 looks like the curve of memristors.