Backyard Aquaponics
A place to discuss aquaponics

i reccon it could be done so that you get another use of the heat used to heat the house water if your prepared to get inside the heater and add another water coil

the down side of this
a)is its more than likely illeagle (a sick bird )
b) wouldhave to be quite close and insulated well
c) would only work when the heater is used to heat the house water

i guess its a only slight gain in heat for the effort but its using energy that you have already bought so it cant hurt can it


i think when i get mys system goin and if it needs heating i willbe goin the oll black polly pipe on the roof way

Cheers
Pete

would be good if we could bake them into ceramics... just normal clay... it allows heat to transfer... Once the exams are over and done with I will chat to the art teacher regarding placing a copper pipe encased in clay into her kiln...

Pulled out some old note of mine (I trained as an art/geography/special needs teacher originally and still have the clay work notes/guidelines...)
the firing temps for clay are higher than the melting point of copper - so would have to go for mild steel...
here is the data:
Melting point of mild steel is 1515 °C
Melting point of copper is: 1084 °C
earthenware clays fire at 1121 °C (max)
Stoneware/porcelain clays fire at 1121°C - 1315 °C (max)

Stoneware would be better as it is not porous, where earthenware can be very porous

mild steel would probably rust out far too quick wouldnt it ?

especially after being exposed to high temps ...
rust = oxidisation... you need air in the water, so if the water has a high DO, then it will rust faster

AM, you could use the mild steel rod as a "mould", pull it out of the clay and thread the copper tubing through?

yes... but picture it... there would still be copper exposed to the water

What about using a copper enamel technique to coat the copper with essentially a layer of glass? Does that help you get where you want to be?

it would... but I have never worked with enameling copper before so I have no point of reference RE chipping, level of insulation, composition of glass dust etc...

The layer of glass you get in copper enamel is pretty thin, I don't think it would insulate very much. Composition would be similar to pottery glazes. It will chip if you drop it, I'm sure.

How about using mild steel, encase it in stoneware, fire, and put in place as your heat exchanger. Sure the steel will rust eventually, but the stoneware should stay in tact and be watertight, if it's glazed in dark colors, it should absorb heat well, and although NJH might not approve of the heat exchange, water is a great heat carrier.
As the steel rusts, it will eventually add iron to the system, have the hot water come out through a charcoal filter to provide anaerobic microenvironments to get the iron into a useable format for the plants.

Come to think of it, you might want the hot water to mix with your fish tank water as quickly as possible to avoid baking your bacteria.

Thinking about it, would it really matter if the rod rusted away completely... the stoneware would still have the "pipe" through which the water could flow....

Don't know how much loss of efficieny that would result in....

I would be afraid that encasing anything in stoneware and firing it would cause the stoneware to crack. Pottery shrinks maybe 10% when fired, and the steel would probably not.

You could fire a tube of clay, and with a bit of luck, you might get a length that didn't crack. I'm still a bit confused, though. Aren't we just trying to keep the copper from having long term exposure to the water? Can't it just be sealed/painted with one of those water-tank sealers?

Some of you were talking about refrigerator coils as a possible tubing source. I wouldn't recommend using them as the system uses freon which is known to deplete the ozone. If you do not use a vaccum pump and have a resevoir tank to hold the evacuated freon you will release it into the atmosphere with the first cut into the line or removal of a fitting.

The point about the clay shrinking during firing is one a valid one, however one potential solution is make molds for the ceramic and using a slip pour. (Johnny can talk to the art teacher about the making of a mold and using slip instead of solid clay.) Then you can glaze the interior and exterior of the ceramic block with ceramic porcelian glazes. If you didn't want to use a glaze, then you might look into using a flexible poly tubing (like an air/water line). The biggest problem with using the flexible tubing is getting it into and then snaked through the ceramic block.

Kevin

Sorry Aqua, I thought it was Johnny who was talking to the art teacher about the firing temp of ceramics vs. the melting point of copper.