4 ms·

Central heating especially can be much more efficient than simple resistive heating. Here, central heating runs on waste heat. You can also use heat pumps more

Central heating especially can be much more efficient than simple resistive heating. Here, central heating runs on waste heat. You can also use heat pumps more efficiently than resistive heating. Incandescent bulbs are inefficient even for heating (to say nothing of the OTHER half of the year when you'd still be wasting massive amounts of energy.)

inciampati 7y ago
Isn't the waste energy from the inefficiency of the incandescent bulbs fully deposited in your house? What is the other source of inefficiency that makes them inefficient for this by-use? The overall replacement cost? Just curious.
- icebraining 7y ago
  > Isn't the waste energy from the inefficiency of the incandescent bulbs fully deposited in your house? Yes, and that mean an incandescent bulb is 100% efficient: all power used is converted to light+heat. But other systems can be more than 100% efficient - they can add more heat than the power they use. Or, in the case of central heating from waste, unused heat will probably have to be pumped off anyway, so using it is energetically free.
- nordsieck 7y ago
  > Isn't the waste energy from the inefficiency of the incandescent bulbs fully deposited in your house? Yes. > What is the other source of inefficiency that makes them inefficient for this by-use? Heat pumps are more efficient at heating than resistive elements because they take advantage of already existing environmental heat, whereas resistive heating has to generate all of the heat directly.
  - wjnc 7y ago
    Thanks for this insight. Never thought about this. I'm still on old-fashioned gas so in my case the only difference is one of gas being cheaper per joule even after the (in-)efficiency of burning than electricity. But indeed in the heat pump world you get more joules in heating than you put in in Wh of electricity. Still you should amortize the cost of pump per joule of heating. Bulbs were _cheap_.
    - WAHa_06x36 7y ago
      No, what you should be amortising is the cost of the collapse of ecosystems and drowned cities due to global warming. Stop burning gas.
- xyzzyz 7y ago
  Most popular way to make electricity today is to heat up lots of water (via burning coal or uranium) to temperatures on the order of 500 degrees C (1000 F), and have the resulting steam power the turbine, which generates electricity by spinning magnets. This process is generally 20-40% efficient, that is, only 20-40% of generated energy is turned into electricity. The rest of the energy is waste heat of steam that cooled down so much that it's no longer economical to generate electricity from it (because the efficiency of the process goes down as the temperature difference between working fluid and environment goes down). The result is that more than half of the energy simply disappears in the thin air. To increase efficiency, many cities run cogeneration plant, where the waste heat from electricity generation is piped into municipal heating system. In this scenario, the incandescent bulbs are wasteful way to heat the house, because it only uses 20-40% of the energy of the fuel, while municipal heating uses only waste energy to produce eletricity.

inciampati 7y ago

Isn't the waste energy from the inefficiency of the incandescent bulbs fully deposited in your house? What is the other source of inefficiency that makes them inefficient for this by-use? The overall replacement cost? Just curious.

icebraining 7y ago
> Isn't the waste energy from the inefficiency of the incandescent bulbs fully deposited in your house? Yes, and that mean an incandescent bulb is 100% efficient: all power used is converted to light+heat. But other systems can be more than 100% efficient - they can add more heat than the power they use. Or, in the case of central heating from waste, unused heat will probably have to be pumped off anyway, so using it is energetically free.
nordsieck 7y ago
> Isn't the waste energy from the inefficiency of the incandescent bulbs fully deposited in your house? Yes. > What is the other source of inefficiency that makes them inefficient for this by-use? Heat pumps are more efficient at heating than resistive elements because they take advantage of already existing environmental heat, whereas resistive heating has to generate all of the heat directly.
- wjnc 7y ago
  Thanks for this insight. Never thought about this. I'm still on old-fashioned gas so in my case the only difference is one of gas being cheaper per joule even after the (in-)efficiency of burning than electricity. But indeed in the heat pump world you get more joules in heating than you put in in Wh of electricity. Still you should amortize the cost of pump per joule of heating. Bulbs were _cheap_.
  - WAHa_06x36 7y ago
    No, what you should be amortising is the cost of the collapse of ecosystems and drowned cities due to global warming. Stop burning gas.
xyzzyz 7y ago
Most popular way to make electricity today is to heat up lots of water (via burning coal or uranium) to temperatures on the order of 500 degrees C (1000 F), and have the resulting steam power the turbine, which generates electricity by spinning magnets. This process is generally 20-40% efficient, that is, only 20-40% of generated energy is turned into electricity. The rest of the energy is waste heat of steam that cooled down so much that it's no longer economical to generate electricity from it (because the efficiency of the process goes down as the temperature difference between working fluid and environment goes down). The result is that more than half of the energy simply disappears in the thin air. To increase efficiency, many cities run cogeneration plant, where the waste heat from electricity generation is piped into municipal heating system. In this scenario, the incandescent bulbs are wasteful way to heat the house, because it only uses 20-40% of the energy of the fuel, while municipal heating uses only waste energy to produce eletricity.