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Thermoelectric heating stands at the brink of commercialization

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Re: Thermoelectric heating stands at the brink of commercialization

#41

Post by magicalhippo »

antisthenes wrote: post #9
bilsbie wrote: post #4

I’d pay a premium for a solid state AC or heat pump. It’s absurd how much they cost to install. And I don’t get why replacing one is an all day job for three people. There should be standard connections they just plug into. Like a dishwasher.

What in the world are you talking about? The hardest part of installing AC is the ductwork. Swapping out the outside + inside heat exchanger unit is a 1-person 3-4-hour job. Sorry if some HVAC company scammed you, but it's definitely not a 3 person job, unless we're talking some commercial building 5+ ton units.

We got a Mitsubishi Kaiteki[1], which is a mini-split from what I can gather. We just call them "air to air heat pumps" here in Norway.

Anyway, the install itself was about $400, took one guy a few hours like you said. Another $200 for the electrician which had to hook up a dedicated circuit for it as per regulations, though he did it as part of a larger job so would have been $300 as a stand-alone deal.

Total it was $2200. This is considered a premium unit over here, we could have gotten something cheaper but alas looks matter.

Thing is supposedly guaranteed to provide COP of 2 down to -25C. We've had such low temps here a several times (in fact past week has been around -15 to -17C with a harsh 85% humidity, biting!) and we've never had to turn on the backup floor heating so far. Though you can definitely hear it working harder when it's that cold.

[1]: https://mee.no/privat/produktkategori/luft-luft-varmepumper/...

Re: Thermoelectric heating stands at the brink of commercialization

#42

Post by valenterry »

Kye wrote: post #32
davidw wrote: post #30

We recently got a heatpump and... it feels like witchcraft. It chugs away even at 20F blowing hot air into our house.

At 20F that's probably the backup heat kicking in. Heat pumps start losing their efficiency advantage around 40. edit: apparently I was misinformed, but it doesn't seem like something worthy of being downvoted into oblivion.

Nope. The really good heatpumps (air conditioners) have a COP of 4 at -7 degrees celcius and a room temperatur of 20 degrees celcius.

In other words, with one part of electrical energy, they manage pull 3 parts of of heat energy from the outside air into the room. Hence, they use just 25% of the electrical energy that a electrical resistance heater would require.

Re: Thermoelectric heating stands at the brink of commercialization

#43

Post by tempestn »

deedubaya wrote: post #34
bilsbie wrote: post #4

I’d pay a premium for a solid state AC or heat pump. It’s absurd how much they cost to install. And I don’t get why replacing one is an all day job for three people. There should be standard connections they just plug into. Like a dishwasher.

I was just last month quoted 15-23k for an install in the mountains of Idaho. I got a competitive quote and the price was similar. If it cut my electricity bill in half it would take 10-20 years to break even.

For a mini-split system, or central heat pump? Do you have existing ducts? What's the square footage?

We recently upgraded our central heat pump as the old one died after 15 years or so. IIRC the total was $13k CAD, so around 9-10k USD, which included indoor and outdoor units for a roughly 3000sqft house, with installation. But all the ducting was there already, so it was just a matter of swapping out old unit for new. (Got some nice government grants too, so it was only a few k out of pocket.)

Re: Thermoelectric heating stands at the brink of commercialization

#44

Post by aurizon »

antisthenes wrote: post #9
bilsbie wrote: post #4

I’d pay a premium for a solid state AC or heat pump. It’s absurd how much they cost to install. And I don’t get why replacing one is an all day job for three people. There should be standard connections they just plug into. Like a dishwasher.

What in the world are you talking about? The hardest part of installing AC is the ductwork. Swapping out the outside + inside heat exchanger unit is a 1-person 3-4-hour job. Sorry if some HVAC company scammed you, but it's definitely not a 3 person job, unless we're talking some commercial building 5+ ton units.

There are a few zero pipe mini-splits. They hang across the window frame and use 1 inch of height with an inside bidirectional radiator and an external one, SCrewed down to the window jamb and connected to 120/240 volts internally. They resemble a window A/C, but the rads are below the window level and are wider and less deep. I am getting a few next year. This is one of many. https://www.greenbuildingadvisor.com/article/startup-promise...

Re: Thermoelectric heating stands at the brink of commercialization

#45

Post by tempestn »

antisthenes wrote: post #9
bilsbie wrote: post #4

I’d pay a premium for a solid state AC or heat pump. It’s absurd how much they cost to install. And I don’t get why replacing one is an all day job for three people. There should be standard connections they just plug into. Like a dishwasher.

What in the world are you talking about? The hardest part of installing AC is the ductwork. Swapping out the outside + inside heat exchanger unit is a 1-person 3-4-hour job. Sorry if some HVAC company scammed you, but it's definitely not a 3 person job, unless we're talking some commercial building 5+ ton units.

At least in our case the inside unit was massive. It was definitely a two person job to get it into its location in our crawlspace.

Re: Thermoelectric heating stands at the brink of commercialization

#46

Post by davidw »

patmorgan23 wrote: post #39
davidw wrote: post #38

Earlier quoted context omitted.

No, because the installer set it up right at 20. We do have a gas furnace that kicks in below that. It'd be amazing if someone put together some kind of dynamic calculator that could take electricity and natural gas prices and examine inside temperatures based on a smart thermostat system and rejig the cutoff temperature based on all of it.

Bet you could do this in home assistant

Yeah, if I could figure out the calculations to use and source all the data...

Re: Thermoelectric heating stands at the brink of commercialization

#47

Post by petermcneeley »

UI_at_80x24 wrote: post #23
Loughla wrote: post #3

Earlier quoted context omitted.

Wouldn't that effectively just suck the heat from your home? I feel like that's not a great use of your stove?

Heating with a wood stove doesn't really have a 'medium' setting. You get 100% while it's roaring away, and that slowly diminishes as the fuel burns down. (Yes you can adjust dampers, and air-flow valves to "slow it down"; but that doesn't really work/happen.) I've lived in a home heated by a wood stove for 10 years. You would build-up the stove so it blasts away, goto bed, and by morning there would be enough coals…

This sounds all very "homesteading". If you automate various components including wood feed you could get a better experience.

Re: Thermoelectric heating stands at the brink of commercialization

#48

Post by ericbarrett »

jfoutz wrote: post #19
antisthenes wrote: post #11

Earlier quoted context omitted.

Most burned wood is wood unsuitable for construction. No one goes into the woods and cuts down a 200-year oak to burn in their stove. Short lengths, widths, knots, imperfections, wood waste pressed into pellets, etc. Although you do have a point about it being bad for air quality. Especially old stove installations.

I thought pellet stoves got hot enough to be pretty clean. Co2, yes, but not much else?

Residential pellet stoves sound great but in practice they are not reliable (moving mechanical parts that operate at high temps, electronics poorly shielded from said temps—the manufacturers are pretty shady in my experience), and the cost of fuel varies quite a bit and can be very high. Compare to a wood stove that needs no electricity and can burn just about any combustible solid. Modern wood stoves are pretty efficient, too.

Re: Thermoelectric heating stands at the brink of commercialization

#49

Post by inhumantsar »

antisthenes wrote: post #11
skyfaller wrote: post #7

Earlier quoted context omitted.

To steelman your proposal, I should mention that Low-Tech Magazine thinks you're on to something, although they suggest putting the panels on the stove inside the cabin: https://solar.lowtechmagazine.com/2020/05/thermoelectric-sto... I disagree with that article for the simple reason that I do not consider burning wood to be sustainable, or healthy for anything with lungs. Wood should be used for long-lasting constru…

Most burned wood is wood unsuitable for construction. No one goes into the woods and cuts down a 200-year oak to burn in their stove. Short lengths, widths, knots, imperfections, wood waste pressed into pellets, etc. Although you do have a point about it being bad for air quality. Especially old stove installations.

you're not wrong per se but no one cuts down a 200 year old oak for construction either. softwood like spruce, fir, and pine is the primary wood for construction (at least in north america).
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