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The hunt for the most efficient heat pump in the world (arstechnica.com)

submitted 5 months ago by Oestradiolo to c/climate@slrpnk.net

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A new generation of engineers has realized they can push heat pumps to the limit.

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[-] Cobrachicken@lemmy.world 48 points 5 months ago

"These installers are reaching astounding levels of efficiency by taking extra care to design low-temperature heating systems that warm rooms without using excess energy."

I'd at first really like to find a plumber that does not look at me as if I was an alien creeping out of mud when I tellem that if the central gas heater breaks down completely I want a heat pump. There's really hard conservativism in that business here.

[-] czardestructo@lemmy.world 13 points 5 months ago

I live in a progressive state in the US and currently renovating a house. Holy crap they all fight me tooth and nail telling me what a horrible idea they are. Nothing but problems, always break, oh my goodness what if the power goes out, the grid cannot handle the load so don't do it. These old timers need to go away.

[-] UpperBroccoli 9 points 5 months ago

oh my goodness what if the power goes out

...then your gas or oil heater doesn't work, either...

[-] czardestructo@lemmy.world 8 points 5 months ago

Their point is use a small generator to power the gas heater where as a heat pump is 'impossible'.I mention a whole house battery is in my 5 year plan to which they laugh and say your house will burn down. I don't have the patience. I told them I'm an electrical engineer specialized in battery systems and to let me worry about the lithium fires. That shut him up fast.

[-] evranch@lemmy.ca 2 points 5 months ago

I designed my heating system around a fairly efficient non-condensing NG boiler that takes 40W for the fan. I can run it and the circulators off my battery bank no problem, and handle a sustained power failure. But only because of the natural gas.

I've been integrating a water-water GSHP into it to provide summer cooling and a supplemental heat source from my solar panels. It works well, but in my climate (Rural Canada) I would be insane to completely remove my gas boiler IMO. Heating demand is just way too high on the sort of days where the power goes out. I've been working on plans for a wood boiler but insurance has put their foot right down on anything that burns wood in the last couple years.

Here in Canada we can't get lithium at a reasonable price so I have 10kWh of lead-acid (which as you know is actually 5). Doesn't go very far on a cold winter day with 4 hours of sun and snow on the panels!

On the upside I haven't had to hook my generator to my house in years, I'm really happy with my "grid-independent" system.

[-] Cobrachicken@lemmy.world 5 points 5 months ago

During last winter gas heater servicing I told the plumber to set the unit to 50°C heating water output so I could check if the heaters would get warm enough with a heat pump. 1,5 hours of discussion about old buildings and heat pumps resulted till he complied.

It was just a test setup that could be reverted any time.

[-] skuzz@discuss.tchncs.de 2 points 5 months ago

Are you in my state? HVAC peeps had little to no idea about heat pumps and claimed they were $20,000 to install and only rich people had them.

[-] jmf@lemm.ee 2 points 4 months ago

I ended up figuring out how to do mine myself with a Mr Cool kit when the furnace died due to the fact that every hvac guy believed a 4th gen heat pump would be useless in the northeast us. It gets down to about 0F here once or twice a winter and the heat pump starts struggling to keep up around those temps but it still does its job.

[-] Cobrachicken@lemmy.world 2 points 4 months ago

Whoa, that's f* cold, but with your feedback I'm quite positive all this doomsday feedback I got can be ignored. Problem here is I'll be respnsible for uninterrupted heat and warm water for my tenants, too, so doing these calculations alone, for myself, would not bother me. But there's a ton of responsibility to care for the tenants, and I'd like a professional up for the challenge.

[-] spidermanchild@sh.itjust.works 23 points 5 months ago

"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@lemmy.world 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

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 3 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.

[-] Oestradiolo 13 points 5 months ago

Be great if I could afford one though

[-] spidermanchild@sh.itjust.works 13 points 5 months ago

Not sure where you're located, but there are often significant incentives for heat pumps. If you're US and low/moderate income, there are big programs ramping up via the IRA that will cover a large percentage of the costs, assuming you're not in a total brain dead state.

[-] Oestradiolo 1 points 5 months ago

Incentives are great for those who could afford it in the first place.

[-] GreatTitEnthusiast@mander.xyz 10 points 5 months ago

Can you not afford an air conditioner? A heatpump is only marginally more expensive

[-] doingthestuff@lemmy.world 6 points 5 months ago

You can get window unit ac for under $200.

[-] MNByChoice@midwest.social 6 points 5 months ago* (last edited 5 months ago)

For under $500 one can get a window heat pump. (They are likely as shit as the $200 window A/C.)

[-] doingthestuff@lemmy.world 3 points 5 months ago* (last edited 5 months ago)

I own one. It's mounted in the wall not in a window but it's a unit that can be used either way. We have central heat and A/C but our heat is a gas furnace. We have an addition that wasn't on the central system and that's why we have the wall unit heat pump/AC. It works pretty well as long as it isn't bitter cold outside (-20 C/ -4F isn't too rare). Also that addition has terrible insulation. (edit to add that the addition also has an ancient gas heater built into one of the walls but it hasn't been used in decades. It has been tested though, it still works but it is scary.)

So I'm pretty happy with that heat pump and it is probably much more efficient than a space heater. But if I was really broke and just trying to survive a hot spell or a cold snap I'd more likely buy a $180 AC unit and a $20 space heater unfortunately.

[-] sping@lemmy.sdf.org 2 points 5 months ago

Where? My $300 U shaped window AC is modern quiet, tidy and efficient, but I was reading about window heat pumps being $2-3k.

[-] LinusSexTips@lemmy.world 3 points 5 months ago

My wall mounted split systems were <$1000 AUD each, 3.5kw. Found a sparkie and a fridgie to do the install, set us back around $3000 for two systems installed.

Great units, added some wifi dongles and tied them into my home-assistant for remote / out of home control & scheduling.

Probably the best addition to our home currently, don't know how we lived here using pedestal fans and gas heating.

[-] MNByChoice@midwest.social 1 points 5 months ago

Search Amazon for "window heat pump".

I cannot comment on quality or efficiency.

[-] sping@lemmy.sdf.org 1 points 5 months ago* (last edited 5 months ago)

Well all conventional air conditioners are strictly heat pumps, but when we say heat pump everyone usually means bi-directional heat pumps - ones that can provide heating as well as cooling. My Amazon results are not that and I was recently reading about them coming to market starting at $2k.

[-] MNByChoice@midwest.social 1 points 5 months ago

This one is $449 and clearly states several times it can heat with a heat pump.

Maybe it is full of shit. I cannot say.

[-] Oestradiolo 2 points 5 months ago

Yes. I cannot afford an air conditioner. That was the post.

[-] evranch@lemmy.ca 6 points 5 months ago

I saw 5 for air-air and was impressed. Then I see SCOP? Oh please. Why not change the scale again to make sure nobody knows what a good value is. Just like SEER on an air conditioner.

SCOP varies depending on environmental conditions!

Real COP or go home IMO. Watts out/watts in, no fudging numbers to confuse consumers again.

[-] witty_username@feddit.nl 3 points 5 months ago

Nice read

this post was submitted on 03 Jul 2024

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