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Comment by trixie_ | Hacker News Reader

Idea to solve the crypto energy problem - sell space heaters as dual purpose crypto miners. People need space heaters. They buy them, but they also mine crypto (as a free byproduct of the space heating). The number of crypto mining space heaters out there dilute the value of dedicated mining so much that people don't bother with it anymore. Even buying the space heater to make money from mining crypto doesn't make that much money - due to the fact that so many space heaters are crypto miners. Problem solved?

Edit/Multi-Reply: Heat pumps are efficient, but they don't replace all practical use cases for a space heater.

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Heat pumps are approximately three times as efficient as electric heating.

That needs good insulation first, or am I missing something? Usually space heaters are warmer, but less efficient. Heat pumps are great if you have time to warm up the space but if it's insulated like an open field, you'll be always cold.

Why wouldn't one insulate the space? Heating is no end in itself.

Heat pump is essentially a "reverse mount of a refrigerator", putting heat in and throwing cold out. In the worst case, the pump will degrade into a heating element, only outputting heat from electricity (which is what a regular electric heater does).

Insulation is not a requirement, but will lower your energy needs to keep a steady temperature.

They also don't provide very much heat output when it's cold outside

It needs to be really cold. Like -15°C and some go as low as -40°C. They degrade in efficiency but are still better than a space heater. In the worst case they are exactly as efficient as a space heater.

Sure, but at the point where the efficiency is sufficiently poor, why not run a Bitcoin miner instead of the heat-pump-turned-space-heater?

As I understand most heat pumps in cold climates are usually installed with "backup heat" sources for this reason.

A mining rig that runs only a few days per year when the outside temperature is too low sounds very inefficient. This is the same problem that the plan to store excess renewable energy by producing hydrogen has. If you have the hardware, you would want to have it running as much as possible.

worst case being 0 K outdoor temperature?

Rather 1:1 electricity to heat conversion.

"Pumping water down hill is more efficient than pumping it sideways"

The CoP of a heat pump is dependent on the temperature potential across the heat pump. Caution to the reader who thinks one could pump heat from frigid external temperatures into their very warm, high temperature house: the very scenario your post suggests they should be used.

Heat pumps are great for increasing thermal potentials and moving heat across them (not for sourcing energy). They're also great for balancing an internal thermal state that is, on-net, in balance (think of a large office building in the morning, one side is being heated by the sun, the other side is frigid -- heat pumps can balance the internal energy demands instead of simultaneously cooling one part of the building and heating the other)

Heat pumps list that temperature in the documentation of the unit.

I think most of the midwest figured this out during the recent cold snap. It turns out the cut off for my heat pump is 10F.

I'm in the process of finalizing the installation of a wood stove insert to provide backup heating during the cold months. Switching to all electric feels a little like burning cash to me.

If you're in the US, there is an incredible 26% tax credit available on stoves (wood and pellet) that are more than 75% efficient. This covers both the cost of the unit AND installation. It's good for about the next 2 years and went into effect in early Jan.

https://www.hpba.org/Advocacy/Biomass-Stove-Tax-Credit

> Caution to the reader who thinks one could pump heat from frigid external temperatures into their very warm, high temperature house

I heat my house with a heat pump. I live in Eastern Canada and we regularly have -20c days and I still heat my house to a comfortable level. Our pump is >=100% efficient all the way down to around -25c at which point it's less and less effective.

These pumps are extremely popular around here. We heat during the winter and cool during the summer with the same unit.

I consider our heat pumps to be our primary source of heat in our house. We only run the gas furnace if we get into sub -25c days which is not often, we had none this year.

I live in an area of Canada where home heat is pretty much provided exclusively by natural gas but electricity comes mainly from nuclear and hydroelectric sources.

Interesting to think about, but by firing up a miner on my graphics card at off hours I'd probably lower my overall fossil fuel consumption and make some money on the side.

Anything I'm missing here?

With the current crypto prices I don't think you're missing anything. I think you're on to something.

plug a usb thermometer and write a script to throttle the hash rate when the temperature is high

There's a few companies that already do that, they rent out servers / processing power (probably via a spot market) which are in people's homes chooching along. The spot market will always be loaded because at some point one of the many cryptos will find it worthwhile.

people do that, but it's not an efficient way to heat. The most efficient heaters pump heat from somewhere else, even when the source has a lower temperature, like the way a fridge pumps heat from inside the cold fridge to the air in your house. (my apologies for assuming you live in a house if you are actually a 12 dimensional entity that lives on a space whale)

This can't work because it just raises the efficiency of mining. That means mining will become cheaper. That means your reward is higher. That means you can mine more for the same money. That means every miner does that, increasing the part of the heat that's wasted.

In the end, the exact same amount will be 'wasted' as before.

Consumers that are already using (electric) space heaters are already paying $X/mo in electricity.

If they are getting value out of a bitcoin-mining space heater, it is justified to run at any time you want heat, because by getting a BTC rebate of any amount would make it cheaper to run than a space heater.

If enough miners are mining for the purpose of heat, it will push non-heat miners out of the market, because the heat-miners are rationally willing to mine at any price (any 'rebate' on expected electricity->heat costs is useful), whereas the non-heat miners can only rationally mine when btc reward exceeds electricity cost.

(We are a LOOONG way from the majority of miners using the heat, but just wanted to point out there is a hypothetical future where the market could eliminate heat-wasted mining)

What do you do with them in the summer? What about warmer climates where you don't need a heater?

The idea is there are enough people using space heaters on the planet at any given time to dilute any gain from dedicated crypto mining.

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