3 ms·

I'm skeptical, how do you separate the hot and cold reservoir in such a system? Afaik peltier elements have bad efficiency cause of this. With liquid/gas you ca

by jona-f 3y ago

I'm skeptical, how do you separate the hot and cold reservoir in such a system? Afaik peltier elements have bad efficiency cause of this. With liquid/gas you can easily have split systems, giving these heat pumps much higher efficiency.

rocqua 3y ago
It sounds like they are physically moving the element between a hot reservoir and a cold reservoir. Apply the field, and move to the hot side to disapate heat. Then remove fron hot side, release the field, and absorb heat on the cool side. That should allow for pretty good separation between the two. I suppose rather than actually moving the element, you can use valves and liquid reservoirs to either let the cold reservoir flow through, or the hot reservoir.
- willis936 3y ago
  That was my most generous interpretation too, but when I read it I didn't see any details on whether or not this is solid state. I'd be suspicious of a high performance solid state heat pump.
  - CoastalCoder 3y ago
    IIUC they're looking at ceramics. Honest question: can there be ceramic fluids?
- jona-f 3y ago
  You're right, but then the heat capacity of the material would have to be low or the electrocaloric effect would have to be very strong for this to be more efficient than gases. Still skeptical. Edit: And what about the surrounding material, pipes and stuff. They are now cycling between hot and cold too, wasting energy.
  - rocqua 3y ago
    You plumb two pipes through the element that are completely separate. Then you enable or disable flow through the pipes depending on the state of the element. No mixing, no loss to the surrounding material. Though this depends on good heat conduction within the material. Presumably though, the switching speed would need to be rather high on both the electrical field and the material. But if the bulk material is cheap enough that you can make it quite massive for a low enough price, I could see it work.
j-a-a-p 3y ago
It is not Peltier. But seems like solid hardware indeed. The efficiency of heatpump is 1.0 thermodynamics. Ie yes there is a transition in fluid / gas, but the efficiency is not because there is a split. Monobloc heatpumps are common, and have similar efficiencies compared to split units.

by jona-f 3y ago

rocqua 3y ago

It sounds like they are physically moving the element between a hot reservoir and a cold reservoir. Apply the field, and move to the hot side to disapate heat. Then remove fron hot side, release the field, and absorb heat on the cool side. That should allow for pretty good separation between the two. I suppose rather than actually moving the element, you can use valves and liquid reservoirs to either let the cold reservoir flow through, or the hot reservoir.

willis936 3y ago
That was my most generous interpretation too, but when I read it I didn't see any details on whether or not this is solid state. I'd be suspicious of a high performance solid state heat pump.
- CoastalCoder 3y ago
  IIUC they're looking at ceramics. Honest question: can there be ceramic fluids?
jona-f 3y ago
You're right, but then the heat capacity of the material would have to be low or the electrocaloric effect would have to be very strong for this to be more efficient than gases. Still skeptical. Edit: And what about the surrounding material, pipes and stuff. They are now cycling between hot and cold too, wasting energy.
- rocqua 3y ago
  You plumb two pipes through the element that are completely separate. Then you enable or disable flow through the pipes depending on the state of the element. No mixing, no loss to the surrounding material. Though this depends on good heat conduction within the material. Presumably though, the switching speed would need to be rather high on both the electrical field and the material. But if the bulk material is cheap enough that you can make it quite massive for a low enough price, I could see it work.

j-a-a-p 3y ago

It is not Peltier. But seems like solid hardware indeed. The efficiency of heatpump is 1.0 thermodynamics. Ie yes there is a transition in fluid / gas, but the efficiency is not because there is a split. Monobloc heatpumps are common, and have similar efficiencies compared to split units.