3 ms·

'Electrocaloric' heat pump could transform air conditioning

23 points by xbmcuser 3y ago

westurner 3y ago
> The use of environmentally damaging gases in air conditioners and refrigerators could become redundant if a new kind of heat pump lives up to its promise. A prototype, described in a study published last week in Science [1], uses electric fields and a special ceramic instead of alternately vaporizing a refrigerant fluid and condensing it with a compressor to warm or cool air. "High cooling performance in a double-loop electrocaloric heat pump" (2023) https://www.science.org/doi/10.1126/science.adi5477 https://www.science.org/doi/10.1126/science.adi5477
- deleted 3y ago
  [deleted]
westurner 3y ago
Electrocaloric effect: https://en.wikipedia.org/wiki/Electrocaloric_effect https://en.wikipedia.org/wiki/Electrocaloric_effect
amluto 3y ago
That 20K temperature difference will need some work. Maybe for hydronic floor heating or ceiling cooling under very mild conditions with excellent heat exchange on the exterior side, but for serious use, it’s not enough. So I guess the idea would be a multistage device? Very cool if it works and can be made without too many moving parts. I think that any really big reduction in refrigerant use will a side effect, though. Sure, modern A/C equipment has some refrigerant in it, but there is a lot of refrigerant in the often-fairly-long pipes between the indoor and outdoor equipment. Electrocaloric heaters (or gas-fired heat—and-hot-water devices or thermoacoustic devices or district heating or much any other fancy technology) will replace indoor refrigerant pipes with water pipes, which are messier if they leak but are otherwise quite environmentally friendly. This could be done today with no exotic tech at all. Just use an outdoor unit with a small sealed refrigerant system, perhaps using propane or CO2 or just less fluorocarbon or HFO refrigerant, and use indoor PEX water pipes to indoor fan coils. Some light regulation could nudge new construction in this direction. You can buy systems along these lines today. Bonus points for the fact that such a system could quite easily control the cooling coil temperature to adjust dehumidification rates.
- foota 3y ago
  I read that as requiring a temperature difference of 20,000 at first, quite the difference!
garyclarke27 3y ago
Sounds promising - Eliminating a compressor should make them much quieter than noisy heat pumps and a/c - this is their biggest problem I think.
- jws 3y ago
  For me it is still airflow noise. I can’t really hear my compressors. But this is one of those blind men and elephant things. If you live in detached housing with space between houses and at least some attention to noise mitigation it is a complete non-issue. When I live in a single room with a heat pump inside with me, it is a huge issue.
legulere 3y ago
With no pressure, I guess such systems would last longer than current heat pumps.
Animats 3y ago
Here's the author's web site.[1] Not finding a relevant paper. 2020 paper from MIT on this subject.[2] It works, but, as yet, is a small-sized effect. Think chip coolers, not house coolers. [1] https://pace.uni.lu/emmanuel-defay/ https://pace.uni.lu/emmanuel-defay/ [2] https://fisherp.mit.edu/wp-content/uploads/2020/10/129.full_.pdf https://fisherp.mit.edu/wp-content/uploads/2020/10/129.full_...
MobiusHorizons 3y ago
They harp a lot on the environmental issues of current refrigerants as a value proposition for this new device. I think that logic makes sense with older refrigerants, but R744 they are literally using CO2 as the refrigerant. Of course CO2 is a greenhouse gas, but in this usage it effectively acts as sequestration. Seems like that is already a really good solution from a climate impact perspective

23 points by xbmcuser 3y ago

> The use of environmentally damaging gases in air conditioners and refrigerators could become redundant if a new kind of heat pump lives up to its promise. A prototype, described in a study published last week in Science [1], uses electric fields and a special ceramic instead of alternately vaporizing a refrigerant fluid and condensing it with a compressor to warm or cool air. "High cooling performance in a double-loop electrocaloric heat pump" (2023) https://www.science.org/doi/10.1126/science.adi5477 https://www.science.org/doi/10.1126/science.adi5477

deleted 3y ago
[deleted]

westurner 3y ago

Electrocaloric effect: https://en.wikipedia.org/wiki/Electrocaloric_effect https://en.wikipedia.org/wiki/Electrocaloric_effect

amluto 3y ago

That 20K temperature difference will need some work. Maybe for hydronic floor heating or ceiling cooling under very mild conditions with excellent heat exchange on the exterior side, but for serious use, it’s not enough. So I guess the idea would be a multistage device? Very cool if it works and can be made without too many moving parts. I think that any really big reduction in refrigerant use will a side effect, though. Sure, modern A/C equipment has some refrigerant in it, but there is a lot of refrigerant in the often-fairly-long pipes between the indoor and outdoor equipment. Electrocaloric heaters (or gas-fired heat—and-hot-water devices or thermoacoustic devices or district heating or much any other fancy technology) will replace indoor refrigerant pipes with water pipes, which are messier if they leak but are otherwise quite environmentally friendly. This could be done today with no exotic tech at all. Just use an outdoor unit with a small sealed refrigerant system, perhaps using propane or CO2 or just less fluorocarbon or HFO refrigerant, and use indoor PEX water pipes to indoor fan coils. Some light regulation could nudge new construction in this direction. You can buy systems along these lines today. Bonus points for the fact that such a system could quite easily control the cooling coil temperature to adjust dehumidification rates.

foota 3y ago
I read that as requiring a temperature difference of 20,000 at first, quite the difference!

garyclarke27 3y ago

Sounds promising - Eliminating a compressor should make them much quieter than noisy heat pumps and a/c - this is their biggest problem I think.

jws 3y ago
For me it is still airflow noise. I can’t really hear my compressors. But this is one of those blind men and elephant things. If you live in detached housing with space between houses and at least some attention to noise mitigation it is a complete non-issue. When I live in a single room with a heat pump inside with me, it is a huge issue.

legulere 3y ago

With no pressure, I guess such systems would last longer than current heat pumps.

Animats 3y ago

Here's the author's web site.[1] Not finding a relevant paper. 2020 paper from MIT on this subject.[2] It works, but, as yet, is a small-sized effect. Think chip coolers, not house coolers. [1] https://pace.uni.lu/emmanuel-defay/ https://pace.uni.lu/emmanuel-defay/ [2] https://fisherp.mit.edu/wp-content/uploads/2020/10/129.full_.pdf https://fisherp.mit.edu/wp-content/uploads/2020/10/129.full_...

MobiusHorizons 3y ago

They harp a lot on the environmental issues of current refrigerants as a value proposition for this new device. I think that logic makes sense with older refrigerants, but R744 they are literally using CO2 as the refrigerant. Of course CO2 is a greenhouse gas, but in this usage it effectively acts as sequestration. Seems like that is already a really good solution from a climate impact perspective