Backyard Aquaponics
A place to discuss aquaponics

Chappo.... most homes don't use copper pipng other than for hot water.... and most new home don't use it at all... partly due to health concerns....

Secondly, and more importantly.... town water is almost always pH 7.0 - pH 7.5..... most bore waters are the same, with some tending to pH 8.0

Consider an AP system almost always tends toward pH < 7.0... ie it's acidic, even if only slightly..... not good for copper.....

Consider that we're running a closed loop recirculating system..... metals are cumulative, both for us and fish.....

Most fish don't tolerate even low levels of copper... and crustaceans will curl over if you even wave a piece of copper pipe in front of them...... and that includes filter feeders, like mussels

Do a search on "heat exchangers" and/or "copper"..... it's all been discussed many times throughout many threads here on the forum.....

Universally.... copper is not an option..... some have/are looking at stainless steel...

And there was a lot of discussion regarding beva tubing.... ie the coils used in post-mix/cooling systems in pubs/clubs...

4:30 pm

Water temp 102 F
Air temp 89.2 F and leveled off will probably start dropping in the next hour.

Almost 5:30 pm
water temp 105 F
Air temp 89.1 F

Not too bad. I expect that if I improve a few things that were just tossed out there, I will get even better results. I will deem this part of the process successful enough to warrant moving forward with the project.

You might like to have a look here for some ideas also TC
http://www.thesietch.org/projects/solar ... /index.htm

WIPM
have some lengths of S/S tubing (1/2")
Got a nice piece of thick glass
have timber to knock up a box

NEED a tube bender - now where is that freight delivery guy

I've read that a good way to source glass is from window installer companies. Very often they just trash the old windows that they have removed.

I'm not sure I wouldn't give it a go with the pump running continuous also, can't hurt anything, and I personally would be interested in seeing how the results may vary.

I know in a forced air HVAC system more airflow across the coiling coil results in the same amount of BTU transfered, but the cooled air temp will be a little warmer than with a slower air speed. Wonder if it would function the same with this setup.

Also I think I would try to sespend the clear plastic sheet over the tubing without contact.


My idea for water cooling if I ever need it will probably be geothermal. one of those big rolls of irrigation pipe buried about 2' deep should do the trick for cooling, and maybe all the heating I would need also. With the added benefit of more overall water volume to aid in system stability.

We used to have a home made hot water heater on the wood stove at our cabin. No electricity. It was just a stainless box that sat on top of the stove with a pipe coming out of it that went into the bottom of the fire box. once inside the fire box it went straight up and back out and up to the stainless tank. The cooler water in the stainless tank stayes towards the bottom, and the hot water rises up in the tank so when the fire was going it would heat the water in the firebox which caused it to go up in the pipe to the tank and draw cooler water off the bottom of the tank into the fire box. Thermosiphon at its simplest.

And had quick hot water too.

Oh I won't get into the wood furnace/boiler hottub we made.

Thanks Tamo, yeah live close to a glass making company and it easy to get off cuts - the piece of glass I have has been lying around in the garage for some years waiting for BYAP to take over my life

Wow, thanks for that link Ell, cool and simple.

And the other ideas comming in. Definitely right about the plastic (actually better plastic exists for the purpose too.) Today's test was what can I toss together quickly (and completely temporarily) and get a result. I got water hot enough for a good hot bath had I wanted it.

I may try just running the pump constantly tomorrow then (provided it is sunny) and see what happens.

I still have it running tonight and will see how much cooling we have come morning.
The water in the container at about 9:35 pm was about 90 F. Air was 76 F Pump still running 1/2 hr on 1/2 hr off.

We've discussed this a few times on other threads. I still cant decide weather to use my solar hot water panel as a cooler or a heater. Here's a few things we've discussed:
- as a heater you would want the glass cover on, but as a cooler you would want in off
- colours may make a difference - a black pipe will absorb heat more readily but a white pipe will radiate it out easier
- a cheep stainless heat exchanger is going to be hard to find. If you find some can you buy me one?
- if you are running a closed system you should be able to get away with a very small pump to get it to a head. Try an externally mounted car water pump or a central heating pump to take the high temps
- you'll need a pressure release in case it gets too hot
- you could consider using a car radiator inside a glasss box as your solar panel if you want to heat water
- as a water cooler in summer I thought you should be able to get a thermosyphon going, but you want to face the panel away from the sun so that it doesn't get any direct sun in the day

Hi TCL
Yet another experiment? I think you`re hooked
It might pay to thoroughly document all the variables so you know whats doing what. It`ll be an invaluable reference when you eventually scale things up

For example,something like "x" feet of pipe with a volume of "y" litres will heat "z" litres of storage tank water by ? degree F over "whatever" hours in your average sunshine.
Add in the flow rate and it should give you an idea of what the system can do and how best to improve the performance.

Hex, we will see how well I do at documenting things. I'm not really expecting to get that detailed but we will see.

I have heard that it is possible to use a solar cooker to make ice by putting in water and aiming the thing at a clear starless patch of sky at night. I don't know how well that works though.
Pool heaters are black and they usually don't have the glass and I understand they function quite well s heaters as well as chillers depending on when you run the pump to them. They usually face South or West in this hemisphere.

Perhaps the best method for both functions in one coil would be to use just the black tubing on the south face of the roof. It might not be as optimal for either one but would function for both. It would also have the benefit of not damaging the roof by trapping as much heat and/or moisture against the shingles. To get the most efficiency of either one, it would require two seprate systems.

With my current plan, I would not worry about pressure build up as the insulated vessel would not be perfectly air tight so I don't need to worry about pressure release valves or anything like that. And the heat exchanger coil would carry the system water in/out of the insulated vessel so that side of it wouldn't need to worry about pressure either as it would be flowing to daylight as it were.

That refrigerator coil panel that Ell linked to looked really cool though. Quite tempting.

I'm not sure about this KE. Colour shouldn't make any difference to an object's ability to radiate heat. It only affects the amount of light/heat that is reflected, so white objects absorb less incoming radiation. Out of the sin, colour should make no difference.
I could be wrong though.

yes and no.

many people will be surprised to hear that white paper has the same emissivity as black paper around 0.95.

emissivity is used as a corrective factor when using infrared (non-contact) thermometers

black paper obviously gets hotter as it absorbs a wider range of the spectrum UV+VIS+IR

as steem has stated radiated heat at night should not make a difference with colour as only the emissivity at IR is relevant.

Some else has linked to http://www.geodesic-greenhouse-kits.com/ before, but they also have an automated vent in the greenhouse roof that uses expanding wax to open & close it.
By inverting the operation [putting the cylinder on the outside] i.e. it closes when it is hot (& vice-versa) perhaps a glass exchanger could be made to operate as desired.