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Anyone know how these pumps manage to squeeze enough heat out of ambient air to make it worth the while? -20 is down there! I understand how heat pumps work, bu
by ethagknight 4y ago
Anyone know how these pumps manage to squeeze enough heat out of ambient air to make it worth the while? -20 is down there! I understand how heat pumps work, but what's the differentiator?
- contravariant 4y agoIt helps if you look at it as temperatures in Kelvin, to bring something from 250K to 300K requires a 20% increase, which can be done by an ideal engine at an efficiency of 300/(300-250) = 6. Sure you can't ever reach that ideal but the upper limit is high enough to make it worthwhile. I'm not fully sure at what point it stops being worth it, but anything above 150K can get an efficiency of more than 200%, in theory at least, and 150K is way above any reasonable ambient temperature. As far as I know the ideal is not even that hard to approach it's just how to do it in small scale and quickly that is the problem.
- fallingknife 4y agoWhat does an efficiency above 100% mean?
- contravariant 4y agoIt means you transfer more heat than work put into the system.
- supertrope 4y agoInstead of burning fuel to generate e.g. 1500W of heat, a heat pump uses 500W of electricity to transfer heat inside generating the same 1500W heating effect.
- Qwertious 4y agoIt's a multiplier for the electrical input - if your heat pump is 400% efficient, then it means the electricity is being 100% turned into heat, plus 3x as much heat is being sucked in from outside.
- yosito 4y ago> -20 is down there! That's 244 Kelvin. It may not seem like a lot of heat to the human body, or judging by the state of everyday elements like water. But in terms of energy, there's actually still quite a bit there.