Nothing to do with cycling - making a well-insulated case for a HW cylinder.

[Globalti]

I have set up a new 160 litre copper cylinder (thanks Ebay!) in the attic plumbed in tandem with the existing cylinder, the intention is to fit a solar panel next spring (Vridian Solar) and run it through the coil to pre-heat the water entering the existing cylinder.

I have deliberately left the connections to the new cylinder long so as to leave space for some really good insulation. The cylinder is already lagged but once it is heated I don't want to be losing any therms.

I thought of constructing a box out of light timber covered in plywood, then lining the inside with Kingspan or a similar insulating sheet and finally stuffing the whole thing with glass wool. It needs to be able to be opened at the front for when I connect to the coil and for any thermostats, which may need to be strapped to the cylinder.

Anybody got any suggestions or thoughts?

 

[Over The Hill]

Interesting idea.
How will the solar heated water get into the first tank? If they are plumbed in next to each other the gas fired water will run into the high side of the second tank if they are just in next to each other.
Should the new tank be lower so the hot water runs up by gravity?

Back on the point- I would just use normal loft insulation (glass fibre stuff) and wrap it around. If you want to be neat then put it into bin bags and strap it around the tank. You could get a good thickness like that.

You are probably adding a fair bit of weight with the second tank so make sure it is wells supported!

 

[Globalti]

The new cylinder happened to fit exactly above the existing one in the attic so the weight is taken nicely by the stud walls of the airing cupboard. Happily this also puts the new cylinder in close proximity to the SW facing part of the roof where the neighbour's tree doesn't cast a shadow and where I shall install the panel. There is no circuit so water heated by the boiler can't flow up from the old cylinder into the new by convection; we simply added the new cylinder into the existing supply from the header tank to the old cylinder. When we buy the panels and connect them to the coil, all that will happen will be that the old cylinder will be receiving its water pre-heated from the new cylinder instead of cold directly from the header tank. The house boiler will then just top up when necessary.

 

[ASC1951]

That's pretty much what we did when we installed a big cylinder in a club cottage some years ago, except that instead of glass wool (which is vile to deal with) we got the two liquid ingredients for insulating foam and poured them into our wooden shuttering. Nearly as vile, but a lot of fun to watch.

Not as convenient if the cylinder gets a small leak, I suppose, but exceptionally effective for heat loss. We only remembered to leave holes for the controls at the last moment.

 

[james_so]

When I was a kid my dad used polystyrene packing chips which he bought in massive bags and simply poured into a simple wooden box he'd built around the cylinder. No mess, easy to remove for maintenance, and cheap (or free if you know someone who gets lots of parcels...)

 

[Over The Hill]

Nice simple system R R - I had not thought of doing it like that.

On the insulation how about using polystyrine sheet to make the box shape up. You get it in big enough bits in builders very cheaply.
For going in it try Vermiculite. About 40 years ago it used to be used for loft insulation.

Let us know how you get on, I quite fancy the idea.

 

[Globalti]

Thanks for the suggestions - I'll post a few pics some time.

The reason for doing it this way rather than replacing the existing HW cylinder with a dual-coil version was simply that the bloke who built the house, installed the cylinder then built the airing cupboard around it. Consequently some of the connections are out of reach. Clever, eh?

If you want to be convinced of how easy this is, study the panel maker's website: http://www.viridiansolar.co.uk/