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# Feather fan heat pump

Copper hairs suck heat out of air
 (+1) [vote for, against]

Like the cpu copper porcupine these copper ribs take the heat but instead of dissipating heat from a CPU into the air I take the heat from the air into a cool plate connected to a heat pump. As heat accumulates on the plate it is taken off (say with cooled water), and thus sent to a cooling unit elswhere or is pumped into an insulated heat storage unit.
 — pashute, Jul 20 2021

Thermal diode, one way heat flow https://en.wikipedi...e#One-way_heat-flow
[a1, Jul 25 2021]

 The copper porcupine is a good form factor for distributing heat from a point source. If you want a cold thing to take heat from a room you're going to need a big fan to circulate the air, pulling it into a Cold Place (tm) and only there it can have its heat extracted.

 If you just make a porcupine cold not only will it get angry and possibly bite you, it will very quickly defend itself with ice from condensation from the water in the air. But even if it couldn't do that it wouldn't come into contact with enough of the air to be effective.

[+] for thinking about and attempting to reverse heat sink form factors. [-] for doing absolutely no research on the topic.
 — Voice, Jul 20 2021

"In this household we obey the laws of thermodynamics."
 — a1, Jul 20 2021

Edited for clarity. Thermodynamics obeyed. Could you Please link to show the problem?
 — pashute, Jul 25 2021

 I think he thinks that you think your proposal would be as efficient at cooling a room as the reverse would be at heating a room. (or, if you like, at removing heat from the source) The problem physics has with that is heat always disperses. You can efficiently remove heat from a point source this way because heat flows from a point of higher to lower concentration. Unfortunately heat won't flow the other way: It won't collect itself from a room into a small heat sink spontaneously. To get heat to flow the other way you have to have active cooling.

 If your heat sink is colder than the air temperature it will cool the air, but it will only cool the air that happens to bump into it and lose energy. To actually cool the room without a fan the heat sink needs to be much, much colder than the air. And if there's no moisture in the air that will pretty much do the trick, with the air churning from the temperature difference.

If you do use a fan and appropriate humidity-deal-withing widgets then you have an air conditioner.
 — Voice, Jul 25 2021

 I think the innovation here is the feather fan shape of the device. Everything else is widely known to exist.

The question then is whether a feather fan is more effective than the usual bladed / finned heatsink kind of design that devices like this usually have.
 — pocmloc, Jul 25 2021

How about fashioning the heat sink into the shape of the blades of a traditional fan and spinning that? The heat transfer coupling might get wonky, but it seems possible. Hmm. If you use staged Peltier elements with non-moving parts you can spin the whole thing and only have to worry about fluid transfer on each side. Incorporate a different shape of blades on the opposite side where the "cold" liquid is and you only have the one moving part, aside from the fluids. Has this been done?
 — Voice, Jul 25 2021

 It is possible to build a thermal diode that conducts heat preferentially in one direction. Requires a junction of dissimilar materials. Perhaps pashute’s idea would work if each quill attached to the plate via a copper– cuprous-oxide interface, or other material pair chosen for the desired temperature range .

But the form factor is still wrong. Fins = large surface area, plate = relatively small surface area. This is good for getting heat FROM the flat surface dispersed from the fins (and as Voice pointed out, heat dissipation from the fins relies on airflow) Yet even with a thermal diode it wouldn’t work so well for bringing heat from the fins to the plate.
 — a1, Jul 25 2021

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