I have just purchased ...

[Steve Firth]

. forty six foot long vacuum flasks.

Later I shall be having fun trying to fix them to a roof.

[Jonathan Schneider]

Dunno about the rest of you but my roof wouldn't take a forty six foot anything.

Jon

[Matt]

Tartan pattern or just plain?

:)

[The3rd Earl Of Derby]

Jesus! that'll hold some tea?

[Huge]

Solar hot water, eh?

How much did that set you back?

(Feel free to email if you don't want to discuss it publically.)

After my latest 'leccy bill (how can we possibly spend GBP1K/year on leccy when we cook with bottled gas & heat with oil???) I'm a lot more interested in solar energy than I used to be!

[The Medway Handyman]

He must have Tommy Walsh coming round!

[Steve Firth]

I haven't got the final bill yet. The solar array is costing me £950. I'll probably be spending another £1500 on controls and a heatbank. I'm being difficult by wanting to take heat from every possible source, that's an LPG boiler, immersion heater, back boiler and the solar array. The array is 5.6 m^2. You can get the same number of tubes for as little as £395, but those are 47mm and the ones I got are 58mm.

For the immersion heater I'm considering having a wind generator and using a couple of the 12 or 24volt heaters offered for use aboard boats. If not those then a 240V wind generator. I'll have to check if the scaffold tube used to take a small marine generator is going to be up to the job of supporting a 1.5 or 3kW generator.

At the height of summer the array will probably produce much more heat than I need so I'm planning to have a radiator outside the house as a diversion load. I had thought to divert the heat into a heat store of some kind, and since we're installing a rainwater catchment tank I wondered about using that. The plumber advised against it, he thinks it will be breeding ground for legionella if it is heated.

I'll check with someone more knowledgeable than a plumber and if it is a really cack idea, I'll consider putting in a swimming pool. It's on the cards anyway to have a half-buried swimming pool, possibly an infinity pool on the terrace overlooking the mountains.

[Guy King]

The message from Steve Firth contains these words:

That's a lot of tea.

[Guy King]

The message from "The3rd Earl Of Derby" contains these words:

Bloody Thermosrays.

[Owain]

You either have teenagers or a Cray in the back bedroom

Or you're in Spain and someone's wired an awful lot of streetlights into your meter.

Owain

[Steve Firth]

Knowing him, the last one is a possibility.

[dennis]

Thats about 25p a days worth of heat in December. About £2.50 a day in July if you can use that much hot water.

[Andy Hall]

You mean somebody punched Tommy's lights out? How come I missed it?

[The Medway Handyman]

If you have ever seen Mr W in the flesh, you woukd have to be a WHB to punch his lights out. He is king huge!

[Andy Hall]

One can but dream....

[AJH]

If you're only heating domestic hot water and you consider it likely you'd need to dump some heat then why not go for a bit extra utility from the wind generated electricity? I doubt a heat pump would be particularly suitable for heating the water all the way from, say, 10C to 95C but it should be possible to get a COP of well over 3 for a Delta T of 20C. I'm thinking along the lines of DIY with an old freezer rather than a bespoke unit.

When the DHW is in surplus then you can run something else off the inverter.

AJH

[lairdy]

And the first isn't.

It's a lotta leccy - lights are the major suspects. I've found the latest low-energy bulbs to be quite acceptable (especially at 99p bogof in Morrisons), but not everyone agrees, or has fittings in which they are suitable.

The Cray remains a possibility ;-)

[meow2222]

There is one big plus for resistance heating: it can run direct off the mill, no storage battery and no controller. You cant do that with heat pumps.

NT

[AJH]

It's the way I have Agent set up, I'm easy really but don't see a great deal of merit in storing loads of this chat.

I agree and that seems to be the thing about wind and solar, you need to keep the capital cost down and that tends to mean KISS.

Having said that with the sort of scheme I was thinking of the additional cost should not be too much and the battery can be small as it effectively just buffers changes.

My reasoning is that heat delivered into the dhw thermal store is worth about 2.5p/kWhr(t) here, possibly double that in Italy. Electricity is worth about 9p unit peak and 3 p/unit off peak, the heat pump has the ability to treble the input electricity. So substituting grid electricity when you can and dumping the surplus to a heat pump is potentially a lot more valuable.

If he's going to by the wind generator anyway I wonder what the extra cost of a charge controller is, the inverter can just be a line interactive ups with voltage sensing on it's battery.

AJH