More DC in the home?

democrates

Many domestic appliances run on low voltage D.C., and need to rectify and smooth AC to DC first. I don't know what the typical efficiency of transformer/rectifiers is, but there is a loss, and it bugs me as there are so many mains adapters in trailing sockets about the house.

I'm wondering would it be worth the effort of wiring my home for DC at multiple voltage levels. Many appliances have a DC in, so I could have a car stereo as a Hi-Fi and low voltage lights for starters. What else I wonder?

As an ex-technician I'm not afraid to open up (out of warranty) appliances if necessary to install a DC-in socket.

Instead of using the mains for the home DC I'd like to use a domestic turbine /solar combo, and run off the battery bank leaving the inverter (another power transfer loss) for things that actually need it.

Does anyone think this is an interesting avenue of exploration?

CJhaughey

I have postulated this before, as you say most appliances not involving heat use low voltage to run.
It be much simpler and cheaper to have a system like the US where they have 2 forms of electricity 110v for most appliances and 220 for the bigger stuff, dryers etc.
Instead of the 110v and 220v have say 14v dc converted at the board and small plugs all around the house. plus 220v for the bigger appliances.
I think that wiring for multiple DC voltages could be a pain but if you could incorporate a switching unit beside each plug that could be set for 12v-14.4-and 18v then it would be a lot more convenient.
You would probably only need a few converted sockets perhaps DIN type plugs?
one concern would be to have a type of plug that wasn't able to be fitted into a higher voltage line.
I think that the losses from the Inverters these days are fairly small and while your idea has merit, in practice it would be much easier to use the standard 220v system.

democrates

Agreed on all counts CJ.
Having looked at this IEA Workshop Summary (link to pdf file) :

As much as 10% of domestic electricity use is consumed as standby power. The consumption is notably consistent across OECD member countries. If the other sectors are included, standby power is responsible for as much as 1% of these countries’ CO2 emissions. More analysis is required to validate these figures.

as well as other threads in the forum I've been inspired to get my act together and plug out the tv and video at night, they are among the worst offenders for high standby power, there's a saving with miniscule hassle, so what if the vcr clock is flashing, a bit of black insulating tape will sort it.
I guess the next priority should be the turbine and solar, and after that if I want to further reduce consumption it would be time enough to experiment with dc.

Capt'n Midnight

CJhaughey wrote:

I think that the losses from the Inverters these days are fairly small and while your idea has merit, in practice it would be much easier to use the standard 220v system.

Too many voltages to use. Many Devices are 5V - USB and things that can be charged from it.
12V for cars is 13.8V-14.4V
12V for computer drives is 12.1V
Other things run on 3V and 9V

CJhaughey

I am not sure what your last post refers to, but what I meant was that in simple terms , DC could be used to power a lot of appliances within the home such as video, radio/hifi etc.
however the time and trouble would be a lot for not a lot of gain.
far better that democrates spent his hardearned and time fitting energy efficient lighting and switching off appliances than try and develop a new standard of indoor wiring:)
my point regarding low voltage DC was that if you had a voltage controller near the socket that could be set to a particular voltage a lot of things could be run off it.

democrates

I've looked at the mains adapters around the house:

Permanently on:
4 DECT Phone base stations 4W
1 cable modem 12W
1 ethernet hub 5.25W
Total 21.25W

Periodic use:
Squeezebox 10W
Cellphone Charger 6.5W
Hair Trimmer 10W
Synthesizer 10W
Electronic Saxaphone 7W
Total 43.5W

The periodic adapters get negligible usage, it's the ones that are permanently on that are the key :
8766 hours in a year x 21.25W = 186.28 kilowatt hours per annum
186.28 units @ 12.2c per unit = €22.72 per annum.

I assume it'll be less than this in practice as the quiescent power consumption should be less than the rated output of the adapter. Particularly for the DECT base stations which should draw far less when the handset is fully charged.

So how much would be saved by having one master mains adapter for the house is looking less obvious than I originally imagined, even if it cut that in half, is €11.36 a year worth the effort I wonder? 3 extra pints, maybe...

In fairness I've left out devices with built-in ac to dc that only need dc. But even adding those in is probably not enormous.

The ESB reckon you'll save up to €14 per annum by replacing one bulb with a cfl (uses 80% less power, lasts up to 10 times longer).

Besides, I've missed the obvious free source of power all along, the phone line! Maybe it's a bit foolish, but I've just ordered every one of these products. You have to hand it to russian scientists, my only concern is how the glow in the dark product glows.