Backyard Aquaponics
A place to discuss aquaponics

Yeah... the mecca of agriculture.... self shearing sheep.....

the mecca of aquaculture..... self cleaning fish ....

Your lawn looks better than usual Steve.

Do you have any plans to expand as the weather warms up?

I always have plans..................whether or not they eventuate is another story!

Know what you mean...a lot of my vegies get eaten straight off the vine also...celery certainly is nice and juicy, pity it takes so long to start producing edible stalks

So today i decided to make use of what little spare time i have left before summer hits.

partially gutted an old "roomy" cut the lines to the evap and welded them to about 4m of 3/8 inch copper in a bucket of 30C water.

Results:

1) the compressor works (these were junked ac's remember)
2) the fan needs a manual spin to get going (run cap, easy.)
3) the actual cooling side worked well, too well. I had liquid flood back to the compressor within about 30 seconds.

I expected it not to work, i just wanted to make sure it fired up after re-gass

What i wasn't prepared for was the result of the maths i did later.

It would seem that to get around 3 sqm of surface area (which is what i need of a coil in still water) i'd need 70 odd meters of 3/8 bare tube. not going to happen

anyway, i've just bought a S/S heat exchanger like the type tony linked to.

using some rough figures it should work quite well and its a neat little package

should have it by wednesday so will update.

The length of copper i used may have worked well for a little fridge compressor, but i'm running 3Kw or refrigeration (hey its for free) so i'll have to design around that.

If the exchanger is rated at 2Mpa (the specs i found are conflicting) then i'll be able to run it on reverse cycle heating too!

These calculations you did - are they proving that NJH's claims were correct regarding the inefficiency of the types of heat exchangers we have been speaking abou. More importantly - does it mean that my 20 metre stainless steel tube heat exchanger is going to be useless?

and yes, thats just about as far as i can walk into the garage

Bump - u miss my question Steve?

......he cant reach your question VB

yep missed it, or maybe my subconsious blocked it out due to certain key wors.

To be honest, i cant remember the convo..............

and no, it doen't mean that your 20M will be useless. The thing that i have to do is match the Kw (Kj/sec) refrigerant flow rate to the "exchanger" otherwise i get liquick back to the compressor and a very very short life span.

The other point too is that i'm working on a 20C temp differential, you may have upto 45C differential, doubles the transfer.

Also, i'll be removing heat at a rate of 2C per hour (not factoring in losses) i'm sure you'd be happy to pick up 5C over the Source of a day.

fret not, you can still play with my tig it may even still be in the room you're going to use, you can sleep on it with an intercooler for a pillow

I've had about 6 or 7 of my tandanus die over the past couple of months...............

I'm really shattered about this, more so becasue i know the cause.............the two yabbies i put in from steve&anges place!

rat bastard things.

The tandans like to stick to the bottom alot and i'm sure the yabbies sneak up on them.

I check my system every day, and fish usually float for a day or two after they have died then they. I have pulled the floaters out to find that they are half eaten.

thats it, the yabbies are coming out!now to catch them!

Get some good info while you're down there vb....and a parts list

have you to blokes got time for a visit to the country.
jim