Plastic hot water cylinders?

[James]

We are talking about 1 bar here... atmospheric pressure. Why aren't all cold water tanks (which are made of plastic) cylindrical then?

[Steve Firth]

Then research it, rather than asking other people to do your homework for you.

You may care to look up "Consolar Conus" and "polypropylene".

[Matty F]

Here is the ideal compromise, that I'm working on right now in the attic. It's aluminium, 2 metres high and has a wall thickness of about 20mm. It should hold about 4000 litres. The weight of the tank is about

300kg:

[Andrew Mawson]

Because they are open to the atmosphere, and at the TOP of the system, so are not subject to any pressure other than that caused by their depth !!! The pressure we are talking about in hot water cylinders is pressure in addition to atmospheric pressure. So a hot tank with my 40 foot head has 1.2 atmospheres OVERPRESSURE so a total of 2.2 atmospheres absolute pressure, whereas the cold tank that you cite has

1 atmosphere absolute pressure (plus a tad due to depth)

AWEM

[Andrew Mawson]

homework

In fairness to the o/p, he did declare it was for a school / college project so was being open about it, otherwise I'd have given him short shrift as well

AWEM

[The Natural Philosopher]

What a work of art that is!

The tank weight may only be 300kg, but full of 4 tins of water..that is a different matter!!

[Alan]

2nd coil is at the bottom of the cylinder below the main one. It is made from a smaller diameter tube than the main one, which has small fins (like a spiral round it) and arranged in a figure of 8, with a "T" piece internally on the input and output connection feeding each loop. I've not bought/installed the solar panels yet, but plan to soon.

I did not consider an external heat exchanger, as I had to replace the cylinder anyway, was going to have one custom-made to suit the space better, so made sense to incorporate the solar coil at the same time.

Alan.

[Matty F]

I'm intending to put it on a 3 metre high column like I've drawn here. It's actually a 4.5 MeV Van der Graaff accelerator dome. I've used a lot of Brasso on it so far!

[James]

FFS what do you think I'm doing - have you never used Newsgroups for research? Does anyone asking for your help with something not constitute "research"?

[James]

Thanks for the information and good luck with the panels.

James.

[Steve Firth]

You're asking opther people to do the work for you.

Not for anything other than a study of newsgroups themselves. I wrote an interesting (to me and a few others) paper on the lessons that could be drawn from Usenet for likely behaviour of irate teenagers wishing to execute DoS attacks.

No it doesn't and it reflects badly on your place of "education" that they seem to be palming you off with a third rate explanation of what research is.

What you are doing is the current teenager's version of nipping to the flat next door and asking someone to write their essay for them or to hand over their notes for copying.

[James]

[...]

Hardly. This is for a research paper for an MSc in Environmental Architecture. This is one element of a wider investigation leading to a

5,000 word scientific paper.

All I asked was if anyone knew why DHW stores were cylindrical and made of copper; I didn't ask you to perform thermal modelling of stratified water columns with and without secondary HE coils/mantles or compare HW storage tanks versus HW TES.

I am not the teenager you suggest having left teenagerdom several decades ago :-(

[meow2222]

If supply of copper decreases, price will rise, and tanks will continue to be copper until prices mean that something else will be cheaper. Then we'll use that. Who knows what it'll be, plastic, cement, steel. I dont see what the proposed problem is.

NT

[meow2222]

Good question, though for another different reason. A round tank uses less material per stored volume than a square one. So why square?

NT

[meow2222]

electrolytic corrosion when other metals are around. So you might need a sacrificial whatnot.

NT

[Derek Geldard]

Aren't they made so they can be shoved through the hatch into the loft.

DG

[Andrew Mawson]

about 20mm.

water..that is

I reckon it'll be more than your whatnots that get sacrificed if you get too close to that Van der Graaff generator

AWEM

[Steve Firth]

Then you really should be ashamed of yourself.

5,000 words eh? Just think you could have had it finished by now if you weren't busy having a hissy fit.

Umm well, no you didn't. But since you ask the reason is because it would be bloody stupid to make them spherical.

Well that was part of your question.

I didn't say that you did.

Then it's about time you grew up, sonny.

I'd love to read your essay, it would at the very least be good for a laugh.

[James]

[snip patronising drivel]

GAL.

Thanks for your help and good luck with whatever you decide to do in life... with your attitude you're going to need it.

*plonk*

[meow2222]

heh. If the water's pure enough it could do both jobs at the same time, vandalgraph and water tank.

NT