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119 points mcswell | 1 comments | | HN request time: 0.208s | source
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bigattichouse ◴[] 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. frankus ◴[] No.44459681[source]
Thanks for the link. One of the projects I'll probably never get around to is a thermoelectric-augmented fan coil unit for air-to-water heat pump retrofits. The existing emitters (and crucially the in-wall distribution piping that's expensive to insulate and vapor seal after the fact) would stay just above the dew point, and then the augmented fan coil would work to remove latent heat (humidity) by dropping a bit below the dew point via thermoelectric coolers that reject heat into the return piping.

It's a relatively small delta-T and in most climates a relatively small fraction of the overall cooling load, so it might just barely pencil out.