A DC household would have to choose a trade-off between multiple lines with different voltages or fewer voltages that need to be adapted to the appliances. And we're right back at the AC situation, but worse since DC voltages are more difficult to change.
But consumers like datacenters can very well plan ahead and standardize on a single DC voltage. They already need beefy equipment to deal with interruptions, power sourges, non-sinus components, and brownouts, which already involves transformers, condensators, and DC conversion for battery storage. Therefore almost no additional equipment is required.
The trade-off between, say, one (relatively) high voltage DC bus throughout the home vs many branches with lower discrete voltages is indeed a problem. With AC, we took the bus approach, running 120v everywhere (in the U.S., higher elsewhere). I’m inclined to say we should keep doing that for flexibility and predictability. But it’s a trade off, like you said. It would obviously help if regulatory and standards bodies came out with official recommendations.
Everything else I can think of in a typical household is basically a mere heater that in principle works equally well with AC and DC of the correct voltage. Even computers can be said to mostly care about the correct voltage since AC->DC conversion is vastly easier than voltage conversion.
Indeed. And that’s quite normal. Our electrical system should serve our modern needs.
> but you can't run that through a home
5V might be too low for that length of wire. But you could most definitely have a low voltage line in your house that we could design around, maybe 12V. Electric vehicles are moving towards 48V for accessories. It seems like lack of a standard is holding us back more than anything else.
Or we could just keep doing 120V in the walls, with a DC supply. Modern DC-to-DC voltage converters are very efficient and small. But maybe I’m wrong. A lot of people seem to believe they are still not good enough yet for such a change to make sense.
> If you're going to have AC and DC then you might as well just have AC.
I arrive at the opposite conclusion. Most things are natively DC. So therefore, power in the walls should be DC and we should covert it to AC near the endpoint where necessary.
AC motors are using way more power than the puddly control boards in most home appliances. So you lose a little efficiency on conversion but being 80% efficient doesn’t matter much when it’s 1-5% of the devices energy budget. You generally gain way more than that from similarly priced AC motors being more efficient.
I know that a long time ago DC-to-DC voltage converters were very large in size, which meant AC would win on space efficiency. But unless I’m mistaken, that’s no longer the case. Wouldn’t a DC refrigerator with equivalent insulation and interior volume have nearly identical exterior dimensions as an AC refrigerator?
Sure, but it’s important to separate what could be built from what is being built based on consumer preferences and buying habits. The average refrigerator could be significantly quieter, but how often do people actually listen to what they are buying? People buying Tesla’s didn’t test drive the actual car they were buying so the company deprioritized panel gaps. And so forth, companies optimize in ways that maximize their profits not arbitrary metrics.