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Nano-engineered thermoelectrics enable scalable, compressor-free cooling

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119 points mcswell | 3 comments | 30 Jun 25 14:51 UTC | HN request time: 0.736s | source
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bigattichouse ◴[03 Jul 25 12:44 UTC] No.44454434[source]▶
A lot of people throw around 5% efficiency for Peltiers, and it's just not true - it depends heavily on the temperature differential and current vs. IMax. You can (with care) drive them >2.0 COP.

This isn't anything like a compressor or heatpump system, but Peltiers get a bad rap... they move heat really well if you're not pushing them to the edge.

Here's a nice chart. At 10k difference and 0.1 current max, you're over 2.5 COP. https://www.meerstetter.ch/customer-center/compendium/71-pel...

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1. quickthrowman ◴[03 Jul 25 14:40 UTC] No.44455553[source]▶
You can get 4 COP with a regular air cooled chiller and up to 7 COP if you add an evaporative cooling tower.

Variable frequency drives have made running pumps and fans a lot more efficient, even residential HVAC equipment is starting to get EC motors or VFD driven A/C motors. I can run my 10,000 BTU (1kW) window unit at 68F for an entire month in the summer and it only costs $50 due to the variable speed fans and compressor pump.

What’s the use case for peltier coolers, wearable cooling?

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2. frankus ◴[03 Jul 25 16:09 UTC] No.44456505[source]▶
I'm not sure of the exact reasons but you don't really see vapor-compression heat pumps in the tens- to low-hundreds-of-watts range. So I suspect there are some scaling factors where the reduced size/noise/complexity of a solid-state device starts to be more important than the extra energy that it uses.

I think most of the commercial bed cooling systems are thermoelectric (ChiliPad, Eight Sleep) and they seem to work fine, but by the time you get to the scale of a small fridge or dehumidifiers the products are generally awful.

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3. londons_explore ◴[03 Jul 25 16:17 UTC] No.44456593[source]▶
machining metal parts to tight tolerances when they're only a millimeter wide is awfully expensive.

But making tiny things with lithography is really cheap (in volume).

The middle ground is what one needs for a 10 watt vapor compression pump. And to my knowledge nobody has built a 1 watt pump with lithography - although an array of electrostatic scroll compressors does look like it could work.