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I've always found it interesting that electric radiators are 100% efficient but if you treat a computer as a radiator then you get the same 100% efficiency but
by rlpb 11y ago
I've always found it interesting that electric radiators are 100% efficient but if you treat a computer as a radiator then you get the same 100% efficiency but extra computations done on top.
- erikb 11y agoWas that a joke? Both points are wrong. Electric radiators aren't 100% efficient, can't be. e.g., some of the transformed energy will be light (the metal gets red when it starts to get hot). And of course if you use a computer then X% will go into the computation. The reason why it might be cost efficient for you is because the server guy thinks he has the same costs for electricity no matter if the server is in the data center or in your home, and therefore pay your bills for the server heater.
- coob 11y agoWhat do you think that light turns in to?
- gnur 11y agoAnd that metal getting red emits light, but that light is then absorbed by the surroudings, as it is absorbed it is converted into heat.
- graphene 11y agoOn your second point, no, a 1000W heater will emit the same amount of heat (neglecting visible light losses, which, as other commenters point out, will be converted into heat later on) as a 1000W computer. This is the first law of thermodynamics, and the fact that the computer is doing computation makes no difference.
- CHY872 11y agoNo. Energy in a closed system is constant, so if a computer uses 1000W and stays itself at a constant temperature, it releases 1000W as heat.
- Retr0spectrum 11y agoPlease don't contribute to a discussion when you have no idea what you are talking about.
- vollmond 11y agoThis seems unnecessarily harsh.
- Retr0spectrum 11y agoPerhaps, but the one thing I find more annoying than people spreading misinformation is when people incorrectly accuse someone else of being incorrect. However, I will admit that my comment did not add anything useful to the discussion.
- gus_massa 11y agoPart of the energy can get transformed into light (mostly infrared) or sound, but unless it goes out by the window, all that energy will bounce until it's absorbed by a the walls and furniture. It's very easy to get 100% electricity to heat conversion if you have not windows. You get also 100% conversion with a normal lamp or a sound system (unless they are very close to a window). You get all the heating, and the light or music for free.
- erikb 11y agoI investigated further into that. The confusion arrised from unclear wording in my memory, I guess. You are right electricity to heat is 100%. The inefficiency of electric heat radiators is in the electricity production being inefficient compared to burning the same resources for heat directly.
- deleted 11y ago[deleted]
- CookieMon 11y agoDoes anyone know the word for this? Physics must have a word for how energy in forms such as electricity can do work, but once transformed into thermal energy it can no longer do work (a temperature difference is required to perform work, and then only at carnot efficiency — a temperature alone cannot perform work). I asked on reddit once, and someone suggested "exergy" but I think that word is explicitly concerned with heat, so couldn't be used to say things like "1000w of electricty provides more exergy than 1000w of gas", or "An electric space heater destroys the exergy of the electricity it consumes, while a computer uses it for computation". So is there a word?
- kozak 11y agoLet me quote "Mysteries of Modern Physics: Time": "Energy is conserved, but it can change forms. If you have energy in a low-entropy form, you can do useful work with it. You can lift something up, drive a car, or fly an airplane. If you convert that energy into a high-entropy form, it becomes useless. A low-entropy concentration of energy is called fuel. We have fossil fuels sitting in the ground with energy in them in a concentrated form. We can extract the energy because the entropy of the fuel is low. Once we burn the fuel, we cannot go back. You can heat a room in your house by burning wood, but you cannot cool off a room in your house by unburning fuel and turning it into wood."
- FiatLuxDave 11y agoExergy is the best word, actually. Another equivalent term is energy quality. Your example sentences are completely correct.