Integrated woodburner, solar tubes, oil combi and underground heatstore.

[noelsquibb]

What is the pit insulated with? Is it also wet? How well does wet celotex insulate?
Nice shade of blue.

Cellotex and thermalite blocks jointed with expanding PU foam and garnished with a layer of GRP
Yes but probably only the lower stuff, as I have never been able to pump out more than a couple of buckets from the insulation layers
Not as well as dry cellotex 
Yes, my favourite, traffic light blue

Bodge-a-doodle-doo!! Luvving yer work, Gravy Miner. And that blue.... positively cycledelik maaan.

heh

they let you out then, parkie

[mespilus]

That vinyl ester resin got a tradename?

Was the ver 100% or did it stink of solvent? Any indication which solvent?

Does 'Traffic light Blue' really mean 'Bike Lane Blue'
or 'Mother & Toddler parking bay Blue'?

[Quakered]

or 'Mother & Toddler parking bay Blue'?

Shocking sexism! Parent and toddler surely!

[noelsquibb]

mespilus,

http://www.cfsnet.co.uk/acatalog/Vinylester_Gelcoat.html

speak to Alex the Techie there for info on the chemical base.

It didnt smell much different to the polyester resin.

I thought traffic light blue was the colour of one of the lights ........    

Careful with those 'off the cuff' sexist remarks,
we have a moderator on high alert, up from err, blue to orange I reckon

[wookey]

Wow, hasn't Noel been busy. Very nice work.

To stop air getting in overflow pipes the end is now fitted with a 90degree bend and short pipe down into the water. Clever really. (bylaw 49 for header tanks). You do that instead of bunging it up with rockwool (which would impede the flow).

[knighty]

so.... the million dollar question....  what are you going to add to the water ?

[noelsquibb]

Wow, hasn't Noel been busy. Very nice work.
To stop air getting in overflow pipes the end is now fitted with a 90degree bend and short pipe down into the water. Clever really. (bylaw 49 for header tanks). You do that instead of bunging it up with rockwool (which would impede the flow).

thanks wookey

I thought about the overflow letting in cold air years ago and decided against the idea of a pipe lowered into the water. If for any reason the water level were to rise a few mm above the overflow pipe, a siphon could trigger and the ball valve would then never shut off.

Where there was a problem with one particular roof tank, I created a U shaped baffle from a piece of insulation sheet, that went into the water a couple of inches and up to the tank cover, forming a separate zone for the overflow and substantially reducing the cold air effect ( it was blowing directly onto the ball valve and freezing it )

My rockwool would impede flow but the micro header tank probably needs to be kept frost free. I doubt theres room for a bend without it touching the torbek float. The overflow is only 15mm below the top of the tank, which is covered but not sealed.  So a balance of risk - During a cold spell, I have to lift a plank to check the tank rather than walk past and see if the overflow is running.

Knighty,

in answer to

.... the million dollar question....  what are you going to add to the water ?

Heat springs to mind .... 

I think I will also chuck in some inhibitor but I'm still waiting for James ( Fiddlers) to tell us what proportion will be going into his monster Akvatherm heatstore ....
And your idea of a splash of oil will almost certainly happen.  I rather fancy some cooking oil, as it could go through the septic tank and be intercepted, if a pump out is ever required.

[knighty]

is inhibitor expensive ?

I still thing car type antifreeze is the best way to go... and it's pretty heap if you buy a 200litre drum....

not only does it stop corrosion and electrolysis it kills bugs etc.. too ! (the bugs bit is a side effect)

it must be pretty good at stopping corrosion/electrolysis.... there's plenty of cars around with boiling hot water pumping through aluminium cylinder heads, steel engine blocks, copper radiators and god knows what else !

(it also reduces the surface tension of the water meaning it picks up/dumps heat better in your heat exchangers, and it increases the heat capacity of the water by about 10% so it's like having a 10% bigger heat store for free....!)

[Stuart]

Knighty which one it that? I've not come across a one that raises the specific heat capacity of the water.

[noelsquibb]

I also understood that antifreeze mixes reduced specific heat capacity but the suggestion has merit for cost effectively dosing 1400 litres of water.

Would cooking oil be happy to sit on top of an ethylene glycol mix ?

According to Wiki it raises boiling point as well as lowering freezing point. Another benefit for solar collector circuits -

Ethylene glycol disrupts hydrogen bonding when dissolved in water. Pure ethylene glycol freezes at about -12 °C, but when intermixed with water molecules, neither can readily form a solid crystal structure, and therefore the freezing point of the mixture is depressed significantly. The minimum freezing point is observed when the ethylene glycol percent in water is about 70%, as shown below. This is the reason pure ethylene glycol is not used as an antifreeze--water is a necessary component as well.

However, the boiling point for aqueous ethylene glycol increases monotonically with increasing ethylene glycol percentage. Thus, the use of ethylene glycol not only depresses the freezing point but also elevates the boiling point such that the operating range for the heat transfer fluid is broadened on both ends of the temperature scale. The increase in boiling temperature is due to pure ethylene glycol having a much higher boiling point and lower vapour pressure than pure water; there is no chemical stabilisation against boiling of the liquid phase at intermediate compositions, as there is against freezing.

[pontiff]

I also understood that antifreeze mixes reduced specific heat capacity but the suggestion has merit for cost effectively dosing 1400 litres of water.

At around 70 degrees C  the specific heat capacity of a 50 50 mix of water and ethylene glycol would be about 15% lower than pure water  ( 3500 J/K/kg as opposed to 4190 J/K/kg).
As you say though, the benefits will probably outweigh this loss.  

( Thanks to my A level class for the calcs. Hope they are correct.... )

p.s "increasing monotonically!"" My new favourite word.

[noelsquibb]

Thank you Pontiff

Even if your students are wrong the numbers look quite pretty 

My electronics teacher at college spoke monotonically and probably could have done a hypnotist act as a sideline.

If only I could have stayed awake enough to have learned anything at all ..............

when you wake up you will remember everything ....... click

Now that would be a great way to cram for exams 

[knighty]

oh, guess I was wrong about the positive specific heat capacity change then.... sorry about that  


maybe I was thinking of "water wetter" - which is a bit like antifreeze.... but a lot more expensive and has mixed reviews some great, some terrible  

[djh]

I thought about the overflow letting in cold air years ago and decided against the idea of a pipe lowered into the water. If for any reason the water level were to rise a few mm above the overflow pipe, a siphon could trigger and the ball valve would then never shut off

A small hole in the top of the bend will break the siphon won't it?

[djh]

I read that you've bonded all the metalwork together, which I think is a good idea. Have you attached an anode to the bond? (zinc, magnesium block etc) Or are you going to impress a voltage on a sacrificial piece of copper or somesuch?

Apologies if I missed this somewhere.