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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

#101

Post by bdsa »

pjc50 wrote: post #68
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.

My Vaillant system claims to do that, but it doesn't have dynamic input of pricing so you have to type it in on the head unit. I'm not sure it's even possible to get an API for dynamic pricing of UK energy prices.

Octopus have a tariff with dynamic electricity pricing: https://octopus.energy/smart/agile/

There's a (third-party?) dashboard of the data here: https://agile.octopushome.net/dashboard

Re: Thermoelectric heating stands at the brink of commercialization

#102

Post by herewulf »

hollerith wrote: post #60
jonstewart wrote: post #21

Earlier quoted context omitted.

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 th…

It's not the wood stove owner that is exposed to the wood smoke, it's his neighbors.

"Northern Canada" -- he doesn't have any neighbours. Wood stoves are fine in such a place. They aren't fine at scale.

Re: Thermoelectric heating stands at the brink of commercialization

#103

Post by com2kid »

ctechbob wrote: post #65
com2kid wrote: post #64

Earlier quoted context omitted.

Isobutane is one of the most common refrigerants in use today... Chemical companies do plenty of actual evil things, there is no need to spread false claims!

Is that why Dupont and Honeywell have been sued repeatedly for anticompetitive practices when it comes to refrigerants? HC's are gaining in popularity but they are being fought every step of the way because they are cheap and there's no money to be made.

Having looked into it more, it appears it is on a country by country basis. And for some uses, flammable refrigerants are not allowed, which further complicates things.

Re: Thermoelectric heating stands at the brink of commercialization

#104

Post by skyfaller »

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.

I think a lot of these could be used for building construction, or for smaller wood objects, if we were sufficiently motivated.

For example, here is an MIT team experimenting with using forked tree branches in construction: https://energy.mit.edu/news/using-natures-structures-in-wood...

Re: Thermoelectric heating stands at the brink of commercialization

#105

Post by pjc50 »

bdsa wrote: post #101
pjc50 wrote: post #68

Earlier quoted context omitted.

My Vaillant system claims to do that, but it doesn't have dynamic input of pricing so you have to type it in on the head unit. I'm not sure it's even possible to get an API for dynamic pricing of UK energy prices.

Octopus have a tariff with dynamic electricity pricing: https://octopus.energy/smart/agile/ There's a (third-party?) dashboard of the data here: https://agile.octopushome.net/dashboard

46.73p per unit at peak time while the average is roughly equal to the regular tariff? That seems like a bad deal.

Does make it very clear where the afternoon peak is though, and that's a nice dashboard.

Re: Thermoelectric heating stands at the brink of commercialization

#106

Post by pjc50 »

speed_spread wrote: post #82
VBprogrammer wrote: post #80

Earlier quoted context omitted.

> If it cut my electricity bill in half it would take 10-20 years to break even. Presumably there is a useful life on your existing heating system. At some point it would need replacing?

Assuming electricity is already used for heating, baseboards heaters are just big resistors and have basically unlimited life.

.. but are way less efficient than heat pumps. It's all about cost of installation vs cost of use.

Re: Thermoelectric heating stands at the brink of commercialization

#107

Post by Retric »

leoedin wrote: post #90
Scoundreller wrote: post #33

Earlier quoted context omitted.

I want a cottage industry of aluminum smelters in cold climates. Pick up a pile of aluminum oxide from a depot, electrolyze it into aluminum at home, and drop off the finished aluminum at the depot for a cheque that covers your electricity. "The theoretical minimum energy requirement for this process is 6.23 kWh/(kg of Al), but the process commonly requires 15.37 kWh." https://en.wikipedia.org/wiki/Hall%E2%80%93H%C3%…

The problem is that heat pumps exist, so resistive heating is never the best option. An aluminium smelting at home heating solution would have a maximum CoP of 2 (as you're reducing the energy usage of the smelter by the same amount). A heat pump could easily have a CoP of 3 or 4.

You have that math backwards. A smelter turns ~1/2 the energy from electricity into chemical energy and releases the remaining 1/2 as heat thus the COP would be 0.5 not 2. However smelting is profitable because aluminum oxide is less valuable than aluminum which more than compensates for the waste heat having zero value at the smelter.

Thus various schemes for combined heat and power etc which take the valueless waste heat and use it for some other purposes like warming homes or greenhouses etc. So while the COP would be 0.5 the electricity would be subsidized by the smelling process. https://en.wikipedia.org/wiki/Cogeneration

Where such schemes fail is generally economies of scale.

Re: Thermoelectric heating stands at the brink of commercialization

#108

Post by serpix »

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…

The solution to this is and has been for centuries is to add mass to the stove.

Re: Thermoelectric heating stands at the brink of commercialization

#109

Post by balfirevic »

kwhitefoot wrote: post #85
pjc50 wrote: post #67

Earlier quoted context omitted.

Replacing like for like should be a fairly easy job. But replacing between different systems does seem to be a nightmare. It's interesting that Americans are retrofitting them into HVAC systems, while in the UK we're trying to retrofit into natgas/water based systems, and seemingly the Scandinavians have gone for .. I'm not sure but it seems cheaper? I upgraded to a "hybrid" system because it was the least cost / min…

In Scandinavia we use air to air heat pumps. We generally don't have central heating of any kind so we aren't so tempted to try to shoehorn the heat pump into a system based on hot water. Air to air is much cheaper and is more efficient because it doesn't need to raise the temperature of the working fluid so much and doesn't require a big fluid to water heat exchanger. I'm having a Toshiba Polar 35 heat pump installe…

How do you deal with ventilation? Central unit, or a device per room? Or just opening windows? :-)

> Air to air is much cheaper and is more efficient because it doesn't need to raise the temperature of the working fluid so much and doesn't require a big fluid to water heat exchanger

It might still be worth it to go with water based system if you're going to have underfloor heating. It requires lower water temperatures, so efficiency hit is not that big compared to air-to-air systems (if there is a hit at all).

As a bonus, there are some savings from using the heat pump to heat the hot water for showering and you get the supreme cozyness of warm floors.

On the other hand, now you need some other way of cooling in the summer as underfloor system will not work for that.

Re: Thermoelectric heating stands at the brink of commercialization

#110

Post by tempestn »

deedubaya wrote: post #84
tempestn wrote: post #43

Earlier quoted context omitted.

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 ne…

Central, augmenting existing electric forced air with existing ducts. Similar sized home.

Wow, surprisingly expensive then. It might be worth getting more quotes if you're still interested. I found the ones we got here varied pretty widely, so you may have just gotten a couple of high ones.
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