Energy use....applainces on standby.

12 V is no good for distribution. Low voltage means high current and high current means lots of heat and lots of lost power. That's why the leccy is stepped up to 400 kV or more for the powerlines.

12 V wouldn't be much use in the house for anything over about 150 Watts. The current would be too much. Take a look at the leads attached to your car battery and imagine those trailing from your electric kettle

12 V is no good for hifi either. 12 V across 8 ohms only gives you 18 Watts.

 

oh well thought there would be a good reason, just thinking about caravans and such like, they seem to do ok on 12v.

yes car leads are thick, take about 120-150a loads esp on diesels <cold start current>.

as for hifi the sonic-t runs on 12v quite well.

 

Try giving it 220V it might sound even better!

 

Sometimes I think my Evo 3 speakers run on farts.

 

Exactly - this is why the powerlines on pylons hum if you're within a few metres of them - they're kicking around SHEDLOADS of current and volts

Guys - WHY do ALL gas applicances have pilot lights? Is there no way a gas appliance can "kick in" without needing to keep an unneccessary flame burning 24/7?

Another q - geothermal - if it takes off and everyone uses it, could it cause problems as you'd be cooling the inside of the earth slowly over time - going from "Liquid hot maaaaagmah!" to frozen moon-type rock?

 

I think people this last week [eg in the garbage press] have over-egged the power losses in the national grid. Generating and distributing power is done at maximum practical efficiency - it has to be, otherwise powerstations and substations would be exploding with Terawatts of waste energy. For example, you only have max loss under max load. Under average conditions it will be far less. The efficiency of any home micropower system will be lower.

Pilot lights are a safety cut-off for the gas supply being lost. They also mean you cant light the gas until air in the supply pipe is pushed out.

Geothermal is indeed a limited resource [as is wind power and wave - relies on the earths rotation]. Its true that the more you load the system the faster they will decrease. But they will diminish naturally regardless, so we might as well use them.
The best way to use the suns energy was suggested by the Israelis [IIRC] a few years ago. You put a very tall vertical tube from near the ground [warmed by the sun] to an altitude where its colder. The constant warm air updraft could drive turbines all day.

Unfortunately, in reality, some numpty would bomb it.

 

I think they're building something like this in Australia at present.

 

http://www.visionengineer.com/env/solar_flue.php

I guess this one is reliant on direct sunshine unfortunately for us brits. There are so many good ideas about though. Seems idiotic that we're still shovelling coal onto a fire to provide most of our energy. When will the government give this stuff heavy investment?

 

(a) They do? The UK must live in some remote time in the past, Dom. Natural gas is used in Melbourne for cooking and the gas cooker that we owned had piezoelectric igniters (i.e., the act of turning on the gas for a particular element also ignited it). It was the same with gas fires (don't know about hot water heaters - ours was electric).

(b) The planet has been toasty down there for the last 1.3 billion years or so, so I don't anticipate it cooling down too much any time soon, just because a few folk on the surface 4000 miles away are going geothermal. The question would be more a question of supply and demand - is the local geothermal resource able to cope with a much increased demand? To make sure of your futue energy needs, move immediately to Iceland or Hawai'i.

 

OK - hands up - it's only our boiler that has this. At my folks', their gas oven doesn't have a pilot light either...

I guess radiant boilers need the pilot because they switch in and out more often than the hobs on a cooker, and if you're lighting a cooker, you'll be by it to check it DOES light...

 

Dom,

I think that these days, the presence of a pilot light in a gas appliance indicates nothing more than the fact that that particular model has been built bdown to a price. My stove top works as Tones described, my water heater does use a pilot light (it's about 8 years old) and my central heating uses electronic ignition to fire up rather than a pilot light. Incidently, the brochure for my heating stated that running a pilot light would cost the consumer about $50 per year.

Solar power has, I reckon, a bit more potential than is generally realised. I'm keen on the idea of changing the local building regs. to ensure that new homes are built with solar electricity generation. This ought to be hooked back into the grid, such that over time, peak daily load on the grid would be supplemented by domestic solar instalations. As things stand here at the moment, it is possible to have solar cells installed on the roof and hooked up to the grid. This means that during the day when they are generating, the power that they return to the grid turns your meter backward. So althought you may not directly be using the energy created by the cells, they are returning power to the grid and saving you money as your meter spins happily backward. Also obviates the need for expensive batteries etc.

Of course, the other thing to consider here is water. All new houses ought to have a water tank. Best to leave that for another day.

Regards,

Stuart.