Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Thermoelectric heating stands at the brink of commercialization

spectrum.ieee.org

Post reply on HN
Print view View original

21–30 of 126 posts

Re: Thermoelectric heating stands at the brink of commercialization

#21

Post by jonstewart »

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.

In my vacation house, I’ve got a Hearthstone Heritage wood stove, neither old nor new, and I believe it has been refurbished a bit. When I ran it over Thanksgiving I put an air purifier next to it and ran it on auto. I’d been concerned about air quality with the wood stove. Pleasingly it ran on low and barely blipped when I’d open the door to add logs. Weirdly, it -would- climb up to medium if I opened the door to the garage — I guess it doesn’t like all the varnish and whatnot from there.

So anecdotally, a stove that’s not a rusty old potbelly and has a good draft seems like it could be okay for air quality.

You can sell the trunk of a 200 year oak (though often they’re hollow if they’re that old) but you will have PLENTY of good firewood left behind from harvesting it, with all the branches. The best use of a 200 year old oak is of course to let it be, the backbone of an entire ecosystem. An 80 year old walnut is another story…

Re: Thermoelectric heating stands at the brink of commercialization

#22

Post by hijinks »

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 quoted 10k a head unit to install mini-splits in a home in the colorado mountains. I needed 8 head units.

It was nothing but "only rich people are buying these right now so lets cash in" pricing

Re: Thermoelectric heating stands at the brink of commercialization

#23

Post by UI_at_80x24 »

Loughla wrote: post #3
grecy wrote: post #2

Something I've always thought about. Northern Canada we run our wood stoves for ~8 months a year. Temp on the surface of the stove is 200C to 300C. Outside is -20C to -40C. Let's say an average of 200C temp delta across the TEC. Throw a radiator on the outside of the cabin, use coolant with a tiny pump to circulate. How much power am I going to generate with a square foot (or two) of TECs strapped to the wood stove,…

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 left to start it up again but quite chilly in the house.

  There is nothing like it.  I love it.  I don't have the same access my father did to family farms, wood lots, and trees.  Today I would look into rocket mass heaters.  Spread that heat out and allow it to more slowly heat a house.

Re: Thermoelectric heating stands at the brink of commercialization

#25

Post by jonstewart »

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?

If you run it properly. A good wood stove will run cleanly as well. It’s all about the secondary combustion. An open fireplace will not get hot enough for secondary and be dirty.

Re: Thermoelectric heating stands at the brink of commercialization

#26

Post by drtgh »

10u152 wrote: post #24

What an article of fluff. Doesn’t give any real technical/engineering information. It’s completely useless unless you show us the COP of the system at varying ambient temps. Heat pumps can get to around 4.0 that’s the number to beat.

A whole article for to say that researchers found a ZT of 3.1 for certain temperatures.

This is what since several years ago many researchers are obtaining (those ZT=3.1, that is 20% of efficiency? for eventual temperatures) with a mean of ZT=2 as much. Peltier effect cells remain inefficient, they are electricity guzzlers.

I don't understand then the article's purpose.

Re: Thermoelectric heating stands at the brink of commercialization

#27

Post by Scoundreller »

NavinF wrote: post #12
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.

There are many YouTube videos of people installing heat pumps by themselves in a few hours. Your quotes are likely inflated by permit requirements and price discrimination. Keep in mind that heating with natgas is way cheaper for most Americans so the HVAC guys know that you have money to spare

> Keep in mind that heating with natgas is way cheaper for most Americans so the HVAC guys know that you have money to spare

Where natgas can lose its lustre is on delivery/standing charges. And sometimes transmission and distribution charges (those usually scale with use, but can make cheap gas expensive).

On smaller/well insulated homes, the fixed gas connection cost can really improve heat pumps economics if you're already on electric grid and can cutoff gas entirely. Or have an aux source like oil/propane/wood.

The fun part is that utilities are generally a regulated rate of return business, so as users disconnect, the base costs go up on the remaining subscribers. Pushing more subscribers to disconnect from the gas grid, pushing cost up on the remaining...

I wouldn't invest in natgas distribution companies in mild-moderate climates.

Re: Thermoelectric heating stands at the brink of commercialization

#28

Post by bilsbie »

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.

Just residential. One guy working in the outside part and one on the inside and one helper.

Seemed like a lot of wiring and charging things. I didn’t think it should take that long either.

Their price was in line with other quotes. I wasn’t paying by the hour or anything.

Re: Thermoelectric heating stands at the brink of commercialization

#29

Post by MichaelZuo »

10u152 wrote: post #24

What an article of fluff. Doesn’t give any real technical/engineering information. It’s completely useless unless you show us the COP of the system at varying ambient temps. Heat pumps can get to around 4.0 that’s the number to beat.

IEEE Spectrum's writing and editorial quality does seem to have gone down over the last decade.

Though I'm not even sure what the target audience is anymore.

Post reply on HN