Backyard Aquaponics
A place to discuss aquaponics

I have two years in Industrial Refergeration(sp?) LOL, RETA certified level two, whatever that is. NH3 is fantastic!
Would it not be easier to just heat the beds with an inbed heater and run the fish water straight up there and back? Guess it would all be hypothetical untill you knew your heat loss in the Green house. Or perhaps, I think steve eluded too, a possible Brine soultion as a heat exchange medium. Not sure if that would be viable with the water connected. Something to ponder over.

a place between work and wedding and AP.

DB, i'm still stuck on something..................

you have water at high temp in your fish tank which passes to your cold greenhouse and returns cold to your fishtank. there lies the problem.

by using a heat pump the way you have described all you are going to do is remove further temperature from your fish tank only to pump it back into the retun water. NET gain is zero plus you have wasted electrical power.

This still hold true even if you used additional water reservoirs, you'd be better off just "T"ing them into the system.

I hope i have not gotten confused. GF do you follow what i'm saying?

even a passive brine solution would have a net gain of zero.

If you're looking at heating the return water then a heat pump IS the way to go (approx 2.5x the heat for the same electrical poweras a resistive heater, but with an air cooled condensor (evaporator actually as it will be running in reverse cycle!).

You would still want to maximise the insulation of the green house as heat lost = power used to run the heat pump for longer.


i some how feel that i may have completely missed your point. Let me know if i have, and comments from all appreciated!

I'm afraid I'm a bit lost...... I'll leave it to you fridgies..

Perhaps a diagram may help DD??

Diagrams!

Steve, both the hot and cold side of the heat pump would be in water, it would be a water-water heat pump not water-air, air-air, etc.

DD, thanks for the pics, will stare at them this arvo and reply later.

Ah, wait...I think I comprehend what you are trying to do. You are trying to get the nutrient-laden water out to your cooler greenhouse without losing all of the heat in the water. It helps me to understand the goal. Now I leave it to the mechanically-minded folks.

Yes steve I do, and there in lies my head scratching. Trying to get my mind around it and what it would entail.
Pulling the heat from the fish tank, putting it into the Green House water and using the green house water to heat the fish tank. Will take some study as to where this heat will or could come from. I'm not going to say it's not possible but I do now know why Dave could not sleep that night!

its the stealing form peter to pay paul thing that is getting me, but like i said i will look at DD's pics and hope it becomes clear what i'm missing.

BTW, what are the regs like for regrigerant handling in the states?

Its pretty tough here.............and before the other oz states say "its lax here" don't you worry none, ARC has their eye on you guys

Their latest newsletter even stated that while you don't need a refrigerant licence to handle HC refrigerents, if you intend on putting them into a system that once used CFC, HCFC or HFC then you must have a licence............not that anyone listens, but their crucifying a few people to make an example................

I don't know, except that you can't use the older CFC stuff. It shouldn't be hard to find someone around here - the electrician who helped me wire the basement might also do that kind of thing.

Only stuff I have worked with is NH3. Also used to make meth so a bit hard to just buy some to play around with.
Dave I can understand taking heat from the fish tank and xfering it into the gh water but the part of then heating the fishtank water has me. Transfering heat from one to another isnt a problem but your green house water will be colder so you will not be able to reverse the process.
Its not really a process of robing peter to pay paul, but more robing peter to pay paul then paul to pay peter. The money has to come from some where or the heat in this case.
A heat pump will transfer heat from one source to another but in my understanding of your requirement you want to transfer heat then heat. Again it will depend on the temp differences and your green house system losses, but in my mind the green house water temps will always be lower then the fish tank water. Am I still missing something?

exactly

DD from someone who worked on refrigeration 25 years ago i think your idea will work. i would suggest that to increase the efficiency of the system you could transfer the heat from the fish tank to the cold water by using a simple heat exchange ie a copper pipe of warm water being past through the cold tank before going into your warm tank. the refrigeration unit would only need to do half the work to transfer the remaining heat to your cold water tank