Switching alternative energy devices

The basic system stores a lot of heat, and its not difficult to tweak it so it stores a lot more. The fabric of the building, as long as its brick or concrete, stores lots of heat. You then make it store more heat by using a 'comfort zone.' This means that instead of a fixed target temp you have a range, a comfort zone. In the afternoon you heat it to the upper end of this zone to maximise the time until it drops to the lower end of the zone.

Now if you put rubble in some of the collectors, and have 2 fans, one for filled and one for empty collectors, you get one set with instant heat output and another with storage. Note the storage temps are much lower than electric storage heaters, so much more rubble is required. The other way to do it is have an external heat store, fanning heated air thru that when the fan supplying the house isnt on.

NT

Can you define a 2.5 KW turbine?

The message from OldNick contains these words:

Even a modest car alternator can do around a kW these days. I know they're not ideal for wind turbine use, but it gives you an idea of scale.

Its not the size of the generator, its the size of the blades..to be efficient in less than a hurricane, that genny is going to be a lot bigger than a sky dish

Smaller than a 2.5KW one I shouldn't wonder. ;¬)

A generator that mostly puts out a small fraction of 2.5kW.

NT

One that produces 2.5kW on a very windy day !

Graham

On Tue, 12 Sep 2006 15:20:15 GMT someone who may be "Pet @

Others have given various opinions on the other bits of this. The only thing to add is that East/West facing roofs are not a great problem. One just uses two panels and an appropriate controller. Evacuated tubes are much better in this sort of setup.

Putting panels/tubes on the wall is also a option, then maybe you'll get a south facer. Putting kit anywhere but south facing is going to kill the payback figures. Some people have put panels at ground level too.

NT

On 17 Sep 2006 05:40:42 -0700 someone who may be snipped-for-privacy@care2.com wrote this:-

Indeed.

Assuming one evaluates the equipment just by simple payback figures. Most people don't, otherwise replacement double glazing and replacing a working boiler with a modern one would be rare indeed.

I think you should do your figures on replacing a boiler with a modern condensing boiler. As gas prices has risen on one year by 25% the figures are overwhelmingly in favour of a new boiler.

I realise some people dont work thru the numbers, but failing to do so means getting a system that doesnt pay when you could have had one that does. Payback equals energy return, and the whole purpose of solar tech is energy return... so I'm not sure it makes much sense to design blindly.

NT

On Sun, 17 Sep 2006 22:33:19 +0100 someone who may be "Doctor Drivel" wrote this:-

You are making the rather large assumption that I have not done so.

They have done, but it now looks like that was a one off. Indeed the government customer group is already warning suppliers that it expects them to reduce their prices in line with the reduction in the cost of gas they buy.

As has already been discussed, one needs to allow for the parts that will fail on a new boiler and thus counteract the savings the boiler will make on gas. Then one has to look at the installation cost.

There are many reasons to replace an old boiler with a modern one (and make the changes to the heating system to make it work properly), but simple payback is not one of them.

On 17 Sep 2006 15:18:32 -0700 someone who may be snipped-for-privacy@care2.com wrote this:-

Blindly advocating a system designed for places like deserts, which have warm days and cold nights, certainly doesn't make sense.

Not too sure how thats relevant here.

NT

Well, looking at the spec for the gennie he is talking about it

I looked into specs for wind gennies a couple of years ago when there was a push on the 1 kw ones and they were specced for a force 6 which is a strong wind and correspondingly less frequent. There are I believe tables available that show how the wind force against days in the year for most sites in the UK.

Rob

The message from "robgraham" contains these words:

Trouble is the energy available is related to the cube of the wind speed. Drop from Force 3 to Force 2 and most of the output's gone.