After the first 20 minutes, the water temperature seemed to increase at a fairly constant rate of 0.0006 degrees Celsius per second. This increase in temperature leads to an increase in thermal energy, which can be calculated as follows:
Here m is the mass of the substance (in this case, water), and C is the specific heat capacity, that is, the amount of thermal energy required to raise the temperature of this substance by 1 degree Celsius. For water, C is 4.186 joules per gram per degree Celsius. So, with 1000 mL of water and my rate of change in temperature, I find that the water requires a power of 2.51 joules per second (or 2.51 watts).
Oh, look at that. Even with this rudimentary measurement system, this power is quite close to that of the Raspberry Pi. The difference is probably due to imperfect insulation. So you can see that the power of cryptocurrency is just thermal energy. Honestly, I’m surprised it worked so well.
Show me the money!
While it’s possible to use a crypto miner to heat your home, that’s probably not why people do it. What is the reward? Well, let’s do some quick calculations. I ran my Raspberry Pi miner for 12 hours. How much money did this produce? Wait… 0.00000006 XMR. Converting this to US dollars, it equals 0.0012 cents (not dollars). Yes, that would be a slow way to amass a fortune. If I ran it for 12,000 hours, I still couldn’t buy a piece of gum. Probably didn’t even use gum.
And that doesn’t even take into account the cost. I mean, mining isn’t free: you have to pay for electricity. The average cost of electricity in the In the United States, the price is 16.94 cents per kilowatt hour. If I run my miner at 3 watts for 12 hours, that would equate to 24 watt hours, or 0.024 KWh. Taking the price of electricity, it would cost 0.41 cents. Let me just do some quick math here. Yes, 0.41 cents is more than the money I created. I’m not a financial expert, but this seems like a bad business model.
Of course, no one other than a physicist would mine cryptocurrencies on a Raspberry Pi. There are sophisticated mining machines (costing thousands of dollars) that allow you to mint coins faster and with less energy. The other element to consider is the future price of a cryptocurrency. Even if the cost exceeds the reward today, perhaps one day it will be worth much more. Finally, a crypto miner could be in a location where electricity is cheaper. It is even possible to run a miner on solar energy.
However, remember that for every joule of energy you put into a miner, you are going to produce 1 joule of thermal energy. You need to get rid of this heat, otherwise it will cause problems for your computers. But cooling systems use more energy, which can make it difficult to produce profitable currency.
But it must work, because there is quite a bit of mining in the United States. In 2024, it was estimated that 2.3% of electrical energy went to cryptocurrency. That’s a lot, and I’m really not sure it’s the best use of our energy supply, especially since cryptography is just an invention.
