3 ms·

Look on the bright side- in terms of real power, the electric oven, vacuum cleaner, AC compressor, and fridge compressor totally swamp the entire load, waste an

by ip26 8y ago

Look on the bright side- in terms of real power, the electric oven, vacuum cleaner, AC compressor, and fridge compressor totally swamp the entire load, waste and all, of those 5V devices. In a perfect world we'd have both AC & DC, and could use whichever was most appropriate. We could feed DC straight from the solar panels to the cell phone. But in terms of what consumes most of the power, in the typical home it's AC loads.

dsfyu404ed 8y ago
>Look on the bright side- in terms of real power, the electric oven, vacuum cleaner, AC compressor, and fridge compressor totally swamp the entire load, waste and all, of those 5V devices. This isn't an appropriate comparison. Those appliances actually do useful things that need to get done so the energy isn't just wasted like it is with power supply inefficiency. Sure a 12vdc circuit would be nice. It wouldn't be nice enough or efficient enough to be worth paying for.
- ip26 8y ago
  The point is the power delivery system we have does a good job for 99% of real power consumed (or whatever the number really is). I hate waste; my mains-connected smoke detectors (1% efficient) and garage door opener (15W standby) gnaw at my soul. But that's scope for improvement, not an efficiency crisis.
  - gnu8 8y ago
    > mains-connected smoke detectors (1% efficient) Those aren’t a waste, they are critical life safety equipment. If their 1% efficient power supply lasts the full 10 year lifespan of a smoke detector rather than 6-18 months like a typical LED lightbulb, I’d say that’s the appropriate level of reliability.
    - ip26 8y ago
      Yeah, they're important & valuable. However, battery-powered smoke detectors do it with 1% of the power. If every home in Australia had two smoke alarms, that means 5,600 kW of continuous and largely wasted energy consumption. I don't mean wasted in purpose: smoke alarms are essential. The wasteful part is the fact that 99% of the power going into smoke alarms goes to converting AC power to DC power. As far as I'm concerned, that's 99% scope for improvement. https://reductionrevolution.com.au/blogs/news-reviews/5842566-99-waste-the-unexpected-energy-consumption-of-smoke-alarms https://reductionrevolution.com.au/blogs/news-reviews/584256...
      - gnu8 8y ago
        That is an incredible amount of energy and I agree that it is worth trying to reduce, but I’m skeptical of adding numerous DC-DC converters to the chain. In the current state, it’s all passive devices between the turbine at the power plant and the smoke detector on the ceiling. I wouldn’t trade that reliability for power savings lightly.
  - rmu09 8y ago
    A smoke detector doesn't need that much power, so efficiency of the power supply is less of a concern. You have to find a useful compromise between efficiency and use of materials. Those additional components for higher efficiency need to be produced which uses resources and energy. Although 15W standby for a garage opener seems excessive.
omgtehlion 8y ago
In a perfect world your fridge and vacuum would use BLDC motors and be happy with whatever dc or ac voltage you give them. As my washing machine already does.

by ip26 8y ago

dsfyu404ed 8y ago

>Look on the bright side- in terms of real power, the electric oven, vacuum cleaner, AC compressor, and fridge compressor totally swamp the entire load, waste and all, of those 5V devices. This isn't an appropriate comparison. Those appliances actually do useful things that need to get done so the energy isn't just wasted like it is with power supply inefficiency. Sure a 12vdc circuit would be nice. It wouldn't be nice enough or efficient enough to be worth paying for.

ip26 8y ago
The point is the power delivery system we have does a good job for 99% of real power consumed (or whatever the number really is). I hate waste; my mains-connected smoke detectors (1% efficient) and garage door opener (15W standby) gnaw at my soul. But that's scope for improvement, not an efficiency crisis.
- gnu8 8y ago
  > mains-connected smoke detectors (1% efficient) Those aren’t a waste, they are critical life safety equipment. If their 1% efficient power supply lasts the full 10 year lifespan of a smoke detector rather than 6-18 months like a typical LED lightbulb, I’d say that’s the appropriate level of reliability.
  - ip26 8y ago
    Yeah, they're important & valuable. However, battery-powered smoke detectors do it with 1% of the power. If every home in Australia had two smoke alarms, that means 5,600 kW of continuous and largely wasted energy consumption. I don't mean wasted in purpose: smoke alarms are essential. The wasteful part is the fact that 99% of the power going into smoke alarms goes to converting AC power to DC power. As far as I'm concerned, that's 99% scope for improvement. https://reductionrevolution.com.au/blogs/news-reviews/5842566-99-waste-the-unexpected-energy-consumption-of-smoke-alarms https://reductionrevolution.com.au/blogs/news-reviews/584256...
    - gnu8 8y ago
      That is an incredible amount of energy and I agree that it is worth trying to reduce, but I’m skeptical of adding numerous DC-DC converters to the chain. In the current state, it’s all passive devices between the turbine at the power plant and the smoke detector on the ceiling. I wouldn’t trade that reliability for power savings lightly.
- rmu09 8y ago
  A smoke detector doesn't need that much power, so efficiency of the power supply is less of a concern. You have to find a useful compromise between efficiency and use of materials. Those additional components for higher efficiency need to be produced which uses resources and energy. Although 15W standby for a garage opener seems excessive.

omgtehlion 8y ago

In a perfect world your fridge and vacuum would use BLDC motors and be happy with whatever dc or ac voltage you give them. As my washing machine already does.