81–90 of 105 posts
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Heat is energy, so I find it surprising that it can't be harnessed. Is it really not possible to take some of the energy out of a system and use it for something?
Not all heat is useful. If there was a magic device that could take any heat and convert it into electricity, global warming could be trivially reversed.
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You can't exactly harness heat; what can be harnessed is a temperature differential , to convert into some form of mechanical motion or electrical potential. You'd need some apparatus that connects the hot mass and some cold sink with thermocouples. Whether that's possible or feasible on the scale of the London Tube, I don't know. https://en.wikipedia.org/wiki/Thermoelectric_effect Instead of that, probably a more fe…
Heat is energy, so I find it surprising that it can't be harnessed. Is it really not possible to take some of the energy out of a system and use it for something?
Just realized that with a battery intended for seasonal storage you only get one cycle per year so for the same ROI as a battery that cycles weekly or daily it has to be much cheaper per kwh of capacity. OTOH it only needs to last for like 50 cycles.
I wonder what the napkin math is vs something like methane synthesis.
For a given kwh of storage that is round-tripped daily, a 1% loss of efficiency loses 3.65kwh per year. For a kWh of storage that is round-tripped once per year, you only lose 0.01kwh. At 70% conversion efficiency the yearly storage still loses only 1/10 the energy as a daily system at 99%.
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This is actually one of the use cases that Satoshi Nakamoto spoke about in regards to Bitcoin mining. The purpose built machines for mining (ASICs) turn electrical energy into heat through performing hashes. If you need electrical heating there's functionally no difference between turning a regular heater on or turning on an ASIC. The benefit of turning an ASIC on instead is you can recoup some of the cost of expendi…
The issue is that modern heat pumps are way more efficient than just a resistor. Not something that was obvious in Nakamoto’s day. Even gas furnaces are more efficient due to transmission losses. If your house is one of the few that have an electric furnace , there’s no difference. For most people, though, there’s a huge difference. Running an appliance such as a computer to heat a house will cost more and be worse f…
Earlier quoted context omitted.
This is actually one of the use cases that Satoshi Nakamoto spoke about in regards to Bitcoin mining. The purpose built machines for mining (ASICs) turn electrical energy into heat through performing hashes. If you need electrical heating there's functionally no difference between turning a regular heater on or turning on an ASIC. The benefit of turning an ASIC on instead is you can recoup some of the cost of expendi…
A French company made a product along these lines already, but I don’t think it’s been updated since 2018: https://blog.qarnot.com/introducing-the-qc-1-crypto-heater/ It’s true this is as good as resistive heating in terms of heating efficiency, but it is still far less efficient than a heat pump. Unless you are in an area with a large excess of renewable energy it probably doesn’t make sense environmentally to use a…
It looks like the same company still makes some products that leverage waste heat from computation (https://qalway.com/fr), just not ones that specifically mention crypto as the source of the computation.
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Heat is energy, so I find it surprising that it can't be harnessed. Is it really not possible to take some of the energy out of a system and use it for something?
Air conditioning is really silly when you think about it. It takes a ton of energy to move some energy outside. It feels like it could be self powered.
Your AC is working hard at pushing all the heat outdoors and making a pocket of cool inside.
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Not all heat is useful. If there was a magic device that could take any heat and convert it into electricity, global warming could be trivially reversed.
There is the Seebeck effect, where you run a Peltier junction in reverse. Efficiency is, to put it mildly, low. [1] [1] https://en.wikipedia.org/wiki/Thermoelectric_generator
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Heat is energy, so I find it surprising that it can't be harnessed. Is it really not possible to take some of the energy out of a system and use it for something?
Air conditioning is really silly when you think about it. It takes a ton of energy to move some energy outside. It feels like it could be self powered.
Air conditioning as we understand and use it today is a gold-plated band-aid over bad design. It's so entrenched you almost can't get a house built any other way.
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Geothermal energy is risky AF though. Even with shallow drilling depths, you risk hitting anhydrite and, in combination with water, massive damage like in Staufen [1]. [1] https://de.wikipedia.org/wiki/Hebungsrisse_in_Staufen_im_Bre...
Geothermal energy for power generation and heat pumps for heating homes are totally different systems. It's like comparing a fireplace in your house to a nuclear power plant.
For more on the general problem of storing thermal (rather than electrical) energy on a seasonal basis see https://en.wikipedia.org/wiki/Seasonal_thermal_energy_storag... I was especially surprised to learn that serious attempts at storing heat in soil and rock have been made https://en.wikipedia.org/wiki/Seasonal_thermal_energy_storag... https://en.wikipedia.org/wiki/Drake_Landing_Solar_Community which in the winter…
The basic idea is that the thermal time constant of a uniform sphere (or other shape of fixed aspect) is proportional to the square of its radius. So, for a sufficiently large sphere, the time constant can become very long, >> 1 year. Rock is a good choice because it's very cheap.
The other thing one can do is store cold. This is useful not only for cooling, but for increasing the efficiency of storage of work, since one can generate heat and cold via a heat pump, then reverse that cycle to recover the work. An efficiency of 65% or so may be reasonably achievable with the high temperature in the temperature range of ordinary steel.