Loss is a really interesting thing to think about. Most people think about the losses just disappearing, and relative to the electrical circuits, they do. I had an interesting experience when I started converting to CFLs and LEDs a few years ago. I found several new drafts in my house I had not been aware of and eventually bought all new windows. The incandescent lighting had basically been functioning as a distributed space heater system. It was significant enough to be noticeable, to me at least. If those lights were sufficient to function as space heaters in cold weather, they must have also been sufficient to cause my A/C unit to overwork in hot weather when the lighting was powered on.
That led me to: what exactly are the cascading impacts of loss in the form of heat in a home?
I don't like to reply to ACs, but your feedback seems meant to be legitimate, so I will assume you're not trolling. Even though the *facepalm* is a bit presumptive. I've clearly spent a lot more time thinking about this topic than you have.
I honestly can't imagine what you have in your house that would reach hundreds of amps on the proposed DC bus. Note that I am not advocating the DC bus running all the heavy appliance loads, but rather only all lighting and consumer electronics loads, something like 1 kW at 24V DC would seem adequate. Telecom has used 48V DC for a long time, so there is some precedent that could be leveraged for designs in this area.
Furnaces and ovens could easily be placed on exterior walls offering limited loss paths to the storage system. These are design changes that would be not dissimilar to those that happened as coal furnaces were replaced by electric ones. People adapted both existing homes and new designs.
I think the environmental concerns driving alternative energy are mostly overblown, but I'd like to see power generation at the home in the name of self-sufficiency and to decrease the global conflicts over energy.
I don't mean to pick on you so much as your question, but the limited thinking you demonstrate with mentioning AC exemplifies the self-imposed challenges we face by looking at problems with a limited frame of reference. There is almost nothing in your house that needs to run specifically on AC.
LED light bulbs run great off low voltage DC, and the lights the new ones produce is fabulous. Almost all your electronics now run on low voltage DC, which means you're facing enormous losses throughout your house through all the wall- or built-in transformers. We need to be putting low voltage DC buses in all new houses and then rely on basic voltage adjustment circuits for things that need higher or lower voltage to operate.
Your outlier appliances, like ovens and furnaces, could be handled through a heat storage form of solar with well-understood thermodynamic properties.
We *have* to stop planning our future based on faulty assumptions. It's like building an all-electric house in the 1950s and asking the builder why the plans make no allowance for a coal bin!
The IBM 2250 is impressive ... if you compare it with a system selling for a tenth its price. -- D. Cohen