3 ms·
> If you put the brake (the paddles in water part) at the top of the tower, you have to pump water up the tower. You have a windmill, so you have a source of e
by twic 8y ago
> If you put the brake (the paddles in water part) at the top of the tower, you have to pump water up the tower.
You have a windmill, so you have a source of energy to do that. Much of the mechanical energy that goes into the pumping becomes gravitational potential energy, which will become heat when the water goes back down the tower. A lot of the rest will be lost as heat during pumping. Either way, it's ending up as heat, which is what you want.
Heaters are the only type of machine which are naturally efficient!
- taneq 8y ago> Heaters are the only type of machine which are naturally efficient! I had a big argument with my physics teacher about this back in highschool. He was so stuck on the "no machine is 100% efficient" dogma that he couldn't look past it to the definition of "efficiency" for a heater in a closed room.
- roywiggins 8y agoAnd for that matter, heat pumps can be more than 100% "efficient", since they move more thermal energy than they consume. https://dothemath.ucsd.edu/2012/06/heat-pumps-work-miracles/ https://dothemath.ucsd.edu/2012/06/heat-pumps-work-miracles/
- gdpgreg 8y agoThey're not a conversion system so you don't measure them in terms efficiency, rather you use coefficient of performance, you can never have efficiencies above 100%.
- MrStonedOne 8y agoIn power terms it is above 100% efficient because the watts in is lower than the watts out.
- irq11 8y agoNo, the heat moved is greater than the watts in. The machine itself has considerable parasitic losses, and a simple electric baseboard heater is more “efficient”, using the strict definition of the term. The difference is that most people don’t care about “efficiency”; they care about heat moved per watt. But it matters a great deal more when you try to use a heat pump in a really cold environment, as the heat-transfer ratio of the machine plummets (which is why, in the real world, heat pumps fall back to gas or electric in cold weather). It also matters in a scenario where you’re comparing two different machines that are powered by something small and intermittent, like a windmill.
- gpm 8y agoI'd assume that some tiny fraction of the energy is directly converted to radiation that escapes the room instead of kinetic energy. Some of the energy should be transferred to particles outside of the room directly by electromagnetic forces (they fall off to near zero quickly, but never fall off to zero). Etc. Probably 99.many_9s efficient, but I don't think it could be 100%. (We'll assume you're talking about a resistive heater, fire, or so on. Not a heat pump where you can play games with the meaning of 100% efficient)
- jtolmar 8y agoEnergy is conserved (under normal conditions) so everything is 100% efficient if you want to include waste heat. However, "efficiency" is actually a value judgement. You probably want to heat something specific, so you're going to lose some fractional efficiency by accidentally heating something else. Resistance in the wires leading to your heater will accidentally heat the outside of your house. It's also not a terribly useful definition of efficiency environmentally: if you multiply the efficiency of burning fuel to produce the electricity by the efficiency of your electric heater, you get a worse result than burning fuel in your home. And it's not a terribly useful definition as a consumer either, since that electrical heater is only producing about 50% the heat that a heat pump could do with that electricity.