On Jun 22, 8:37*am, MM wrote:
On Sat, 21 Jun 2008 13:38:22 -0700 (PDT), wrote:
On Jun 21, 5:47*pm, MM wrote:

I've made the first stage, i.e. the copper tube, about 3 metres of it
in a "snake" pattern. This will be mounted on a south-facing wall. Can
I feed the hot water (on thermo-syphon principle) into a black plastic
cold water tank as used in the loft? Or will this plastic release
toxins when containing hot water?

NB: The tank will be mounted initially on outside wall, above the
copper tube "snake".

Or maybe you have suggestions for alternative tank suitable for hot
water?

The cold water tank I'm looking at (on the B&Q web site) is the Titan
Wizard 25/15 Rectangular Water Tank KM15 Black.

MM

Such tanks are unsuitable for hot water, they soften and collapse,
possibly inflicting nasty burns. People have even died this way

I hope your description of your solar system is quite inaccurate, as
its not going to achieve much as described.

What kind of (metal? plastic?) tank would you therefore recommend?

As long as my thermo-syphon domestic solar water heater can produce 15
litres hand-hot water for washing up and 5 litres for my daily
ablutions, that's all I'll want from it! I know I can get half a
bucketful of really hot water just from a garden hose in the sun. And
even if I only got a kettleful for shaving from my contraption, that's
one kettle for which I don't need to use electricity or burn oil to
heat.

MM

Right - 3m copper pipe in the sun isnt going to get you much though.
Add it to a tank of colder water with no circulation and forget it.
Sounds like you'd be better off with a hosepipe pancake collector.
Make it a decent size and you wont need a tank at all. The hose can
store several litres, and since you need lower temp you can dilute the
hot at point of use, thus will require less than 15 litres in the
collector.

The pancake collector would get hot enough to self sterilise, and will
be flushed regularly. Your tank approach would be right in the
bacterial breeding zone, and never get flushed out.


NT