Solar Heating / Wind Power / Solar Power / UK Grants

[Si]

In message , [e-mail] writes

Mine does that too, I have a theory which is admitted to be correct but it is in my best interests to not voice it nowadays. ;-)

[Huge]

Annuities. :o(

[Huge]

Yep. In fact, ours went off an hour ago, at 21:30.

[Huge]

I knocked a couple of hundred a year off by switching from 4 machines on all the time to one that's only switched on when I'm using it. Sorry, SETI@home but my 'leccy bill is more important.

[Derek Geldard]

Hmmm.

You are correct of course.

However the greatest developments in my field (electronics) took place during WW2

Delays in engineering had to be acceoted within the circumstances they had to work in.

DG

[The Natural Philosopher]

well it is my field too, or was..

"An engineer is someone who can do for sixpence what any damn fool can do for a quid"

[John Rumm]

Technically speaking I leave my heating on 24/365, and let the programmable stat deal with it. The result is that it never seems to fire at night when the stat temp drops to 15 from 21, and hardly ever fires for the seven or so warmer months of the year.

[David Hansen]

On Tue, 8 Jan 2008 17:46:00 -0800 (PST) someone who may be [e-mail] wrote this:-

Such things take along time to repay the investment if one only considers simple payback period. It is getting less, but it is still long. However, simple payback period is not the only reason for doing something, if it was there are many things we would not do. What is the simple payback period on a new kitchen?

[David Hansen]

On Wed, 09 Jan 2008 09:27:29 GMT someone who may be Skipweasel wrote this:-

It is not just the whiners. The volume house builders want to slap down their standard designs so as to maximise the number of boxes they can get on a bit of land. They are the ones with the means to influence officials and party politicians.

[Peter Parry]

As has been pointed out to you on many occasions your comparison is invalid. Something like a kitchen is bought for both functional and aesthetic reasons. The first are quantifiable, the second are not.

Energy is entirely quantifiable, there are no aesthetics. You buy on cost whether that cost be financial or some other measure such as CO2 emissions in its generation. Whichever it is is entirely measurable.

A Windsave Turbine on an urban roof in probably more than 90% of UK homes is never going to save money. In about half or more of the installations it would actually cost money to run as the controller consumes more energy than the turbine generates. In probably all cases it will never pay back its construction, distribution, fitting, repair and maintenance energy costs in its lifetime. It is more expensive both in financial and energy terms than almost any other generation system. Why would one fit one?

[Huge]

In order to get into heaven?

[David Hansen]

On Thu, 10 Jan 2008 10:24:33 +0000 someone who may be Peter Parry wrote this:-

So some claim. However, I have yet to find their claims convincing.

[kevallsop]

That may not be that case for much longer:

"The company [Windsave] will launch solar energy products this year and is also working on an unusual version of hydropower - using "grey water" from a household to drive a turbine in its drains".

A turbine in the drains - more or less efficient than a washing machine motor and some fan blades on the roof?

[The Natural Philosopher]

If it means eating at home rather than eating out, about a year in our case :-)

>

[Skipweasel]

Sure, but this was in a much extended post-war asbestos prefab. The original house was a small core inside what ended up quite large.

[Roger Mills]

Almost certainly less so! If you think about it, all the grey water leaving the building will have come in through the mains. How much energy do you think you could extract from the turbine in your water meter?

However, if you *cooled* the grey water with a heat pump, you might just be talking - but I doubt it.

[The Natural Philosopher]

Its total bollocks really.

Far more energy from the shit by letting it make methane, & using a windmill to pump it into calor gaz bottles ;-)

[Dave Liquorice]

A passive heat recovery system would be better would stand more of chance of breaking even for the accountants.

As for power from a basin full of water or even a bath full falling 10' what a stupid idea, this is worse than the tiddly windmills.

The potential energy of a 200l bath 3m above the turbine is only 200 x 9.8 x 3 = 5880 joules or 0.00163 kWhr. Note that is the potential energy, you'd never be able to recover all of it.

[Dave Liquorice]

Correct response. B-)

But please pay attention to my second sentence, there is a balance between making a profit in pure cash terms and making a profit with some other benefit that is not cash. If the former was always applied we'd still be living in caves as there would be no "blue sky" research.

[Andrew Gabriel]

I've had this rather barmy idea floating around in my head for a while relating to shower heat recovery. Run the drain through something like a plate exchanger, which has the cold feed running across the other side (probably the cold supply to the hot water cylinder, not to the shower directly). OK, you probably can't use a plate exchanger for dirty water -- one thought was a really deep U-trap, e.g. 8' for an upstairs shower. The trap is a double concentric pipe with a copper inner pipe with the cold feed in one and the waste water in the other, so there's a reasonable heat transfer contact time. (I've got some lengths of 22 and 28mm copper left from installing the heating, which I could use.)

I would probably never build it, but the idea's been floating around in my head for a number of years now.