this post was submitted on 03 Jul 2024
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A new generation of engineers has realized they can push heat pumps to the limit.

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[–] spidermanchild@sh.itjust.works 19 points 5 months ago (2 children)

"New generation of engineers" is a bit cringe. The old generation knew thermodynamics pretty damn well. All that's changed is they're using R290 refrigerants and variable speed compressors now, but those don't change anything from a physics perspective. COP is fun but it's not even the right metric to use from a policy perspective, just like MPG. And despite being unitless, COP suffers from the same exagerative effect as MPG numbers. What matters is the carbon associated with delivering BTUs to a home, so here you can have the ridiculous case of delivering more BTUs at a higher carbon cost achieving a higher SCOP than the same exact heat pump delivering fewer BTUs at a lower total carbon cost achieving a lower SCOP for a better insulated home, and the person with the higher SCOP bragging about it like a clown. At least when the government tests COP it's a standardized test so you can actually compared equipment (somewhat).

Regardless, nerds gonna nerd and no harm done (and I also track real time energy use of my heat pump, so I consider myself a nerd).

[–] mojofrododojo 5 points 5 months ago

“New generation of engineers” is a bit cringe.

a new sense of urgency is more like it.

[–] chunkystyles@sopuli.xyz 4 points 5 months ago (1 children)

What really matters is the wattage needed to cool the space. That's really it. The less energy used, the less the strain on the grid, or the less solar capacity needed.

[–] spidermanchild@sh.itjust.works 2 points 5 months ago

Wattage is power, not energy. But I still generally prefer carbon as a metric because that's the climate issue, so by focusing on it directly we can make more informed decisions. It also incorporates time of day/seasonal (peak) impacts implicitly, which also have profound effects on the grid, more than total energy used. The essence of our comments is the same though.