Backyard Aquaponics
A place to discuss aquaponics

I believe that to economically use our systems we need to create maximum growth temperatures for our fish. Compromise in temperatures merely sees resources wated and output severly limited.

I accept it is uneconomical to hook up refridgerators if you live in the top-end ,, but for those who live in temperate areas of this country I believe it is viable to run a dual system that makes use of natural thermals , cheap insulation and perhaps a little help from cheap off-peak electricity.

I've been wandering around in my own backyard here in Sydney with my trusty thermometer ,, the neighbours already know I'm crazy , so that's not a worry

Today at about mid-day I took two temperature readings ,, a north facing area that is raised about 60 cm by a cement wall , measurement taken about 25 cm below surface and 60 cms away from wall ,, 25C ,, yep 25C , very nice heater there. 5 minutes later I walked to the south west facing area , get's near no sun and shaded by standard wooden fence ,, 18 C.

My thinking go's like this ,,

1) Hot system , Jade Perch ,, ( with yabbies / red-claw at bbottom of tank under mesh) above ground tank and gravel filter insulated . Pumps to below surface floating raft ( rafts are polystyrene offering surface heat insulation) grow bed situated in the thermal area. Pumping ceases / or minimised between 11pm - 8 am . off peak powered heater keeps tank at 25 C plus during 11pm - 8 am. ( This heating only required in colder months). Warmth and sun loving greens in this grow bed.

2) Cold system , Tank buried in cold area of yard , pumped to surface level gravel bed ( white gravel on top 10 cm ) , this system pumped at will March - Oct , restricted to evening/ night warmer months), but avoiding the heat of the day (11 am - 3 pm , March April May June July August September October). Low light prefering plants in this bed and / or simple reflectors.

I believe using these naturally occuring conditions with a little off-peak power , I can hold almost perfect temperature conditions for both systems / fish for 8 - 12 months per year.

The warm water system could run 12 months no problem as it gets help during it's weakest time ( winter ) by using the electrical heating advantage. I inviasge I will have problems keeping the cold water system below 23C during mid summer . harvest , kill freeze in December would be an appropriate strategy ( Christmas Trout BBQ?) ,, The cold water system now becomes suitable for fingerlings for the warm water system , giving a further 2 or 3 month growth advantage.

Sizing ,, tanks and grow areas need to be assessed on my families requirement for fish and veg/herb/fruit.

!) Fish , we would have little trouble consuming a kg per day. So need 350 odd kilo per year.
Not wanting to stress the fish and taking into account some limitations on pumping times , lets go for 500 fish per tank , culling the weak early should leave 350 good ones. eating fast growers helps keep weight Vs water levels down .....
I'm guessing max loads of around 100 kg fish per tank, so @ 30 kilo per metre I'm after TWO tanks of diameter around 2 metres ,, Pie r squared ,, diameter 2 , r is 1 gives me 3.142 metres.

2) Plants ,, we will have NO problem eating all the veg a system could supply , green veg such as lettuce , spinach, bok choy, water convulvus , etc form a VERY large part of my families diet. Herbs such as parsely , corianda , and several basils are consumed daily in this house. I doubt the system could over supply our veg/herb needs.Sticking to convention learned from this site ,,the warm bed floating raft would be at least 12 metres square ( warmed gravel bio-filter at least 1 cubic metre). the cold system gravel grow bed will be 6 metres square.


The power supply ,, no useless bull-twang wind powered ( no wind no power) or sun ( no sun no power ) crud to be used here. Reliable , cost effective power only ( off-peak used whenever possible) . called energy australia ,, wired straight tooooo your house:) . Supply to my home has been un-interupted except for 2 X10 minute periods and one 1 hour period for the last seven years. An EMERGENCY battery back-up for aeration only , will be part of system.

Pumps ,, least efficient are DC pumps ,, MOST effiecient are 3 phase pumps ,, took a look at the wiring comking to my house ,, already have 2 phases and theres n4 wires coming in ,, so 3 phase no proiblems ,, just checking how ignorant energy Australia think I am on the costings.


Please do make comments , suggestions ,criticisms , actually please blow my whole idea out of the water , if you use facts
Please do NOT suggest dreams such as wind powered ( unless you can supply wind 24/7 sunlight powered unless you can give me sun on cloudy days .....,, or , fart powered systems ( other than maybe EMERGENCY back-ups)

Chappo,
Very interesting ideas. You may already know this but solar water heater can also function as radiant water chillers at night!. I am looking at methods to utilize these two properties of a very simple low tech system to help with my system temps.
http://www.backyardaquaponics.com/forum/viewtopic.php?f=8&t=3344
Something along these lines might come in quite handy for your plans.

Just make sure that you make your floating rafts easy enough to handle so you can get them out of the way for harvesting.

good luck with your planning

TCLynx , Have read your thread and love the ideas.
For my situation , having tank and beds for cold system , placed in the coldest area ,, I cannot see a way to make it cooler without refrigeration ideas ( I did notice the evaporation cooler in another thread) that could ? help me , extend my cool fish production. ( have to think the economics on that one). But at this stage doubt I'll want to use it as I figure on already getting 8 months growth in cold system ( at or below 23C).
What I do really like is your idea of taking heat from concrete , as i said i have a small concrete wall that does amasing heat pluses ,,


A lot more to come , cheers

Not sure I'm following you here Chappo.... you say pumped at will Mar-Oct... but then say no pumping between 11am-3pm during Mar-Oct???

Secondly, you mention running two species... ie. trout through winter....

Presumably that means at least May-Oct/Nov..... no problems there in terms of temperature....

BUT... trout are highly dependant on good quality, fast flowing, highly oxygenated water....

How are you going to provide these conditions if you're not pumping throught your growbeds....

Particularly if you're only pumping during the "evening/night" during the warmer months and then in the cooler months not pumping during the "warmest" 4 hours of the day?.... and especially if you're looking to stock > 100kg of fish.... approaching max size as the temperature warms???

From rough (off the head) calculations... each of your fish tanks will be about 3000ltr....

Assuming your only using 1 tank per system.... from your figures for the "cold" growbed... 6m x 6m x 0.3m = 1200ltr (approx).... of filtration, for 3000ltr of tank water.... with 100kg of trout, around Oct/Nov.....

Given the fact that you intend to site the winter system in a shaded lower temp area... which in itself will limit/moderate plant growth, minimal bacterial conversion due to lower temps... further reduced by no pumping through the growbeds for 4 hours..... or during the day when warmer ???

Hummm...... think you'll be struggling... big time..... not sure how you're going to keep your plants alive and growing ... let alone your fish

Admit to only a cursory glance and rough figures ... it's early ..... but I think you might need to rethink things....


As winter day time temps are (relatively) low even during the height of the day.... why not just pump continuously through the growbeds in the winter system.....

rupe mate ,, you woke up early .COLD / TROUT system , AT will March-October OUTSIDE of hot hours 11am - 3pm ( these times , averaged and would vary a little month by month).May June July pump any time , as you said air temp low even in middle of day. ( and soil temp of buried tank LOW). Immediately either side of given cold period May - July , ( As in April and August) , we need to ensure we are NOT sucking in hot air , so zero pumping say mid-day till 3 pm ( 3 hours no pumping no problem) . Outside of those months again , being March & September / October., longer period of no pumping required ( 11 am - 5 pm ) 6 hours , once again this avoids sucking in hot air and i cannot see it being a major problem for the fish or the plants. ( If plants require a short pump at 3 pm , I still feel tank temps would be ok).

I like to scale things and test ,,

Now questions / comments / ideas on the warm water system?

Yep sure Chappo.... but it's not just about the water temperature for your fish....

It's about filtering the water... providing nutrients to the plants... and oxygenating the water for the fish....

Sorry mate ... but Mar, Oct, Nov.... can reach quite warm temperatures.... 3-6 hours without pumping... oxygenation for the fish, water supply for the plants....

Just don't think it's going to be sustainable... especially with your maximum bio-mass load in Oct/Nov just prior to harvest.... the fish wont stop metabolising, respiring and shitting just because you've turned your pumps off....

In fact during those months, the fish will be nearing maximum size, getting maximum feed, and at near optimum temperatures for metabolisim... especially trout....

That's when they'll be producing the most ammonia, requiring the most oxygen... placing the heaviest load requirement on your filtration.... and you're going to turn it off

You might be able to get away with turning your pumps off between midnight and 06:00 am during winter.... if you provide supplementary aeration directly to your tank....

But I don't really think that with trout, you're going to have to worry about it... can't see your tank getting much below 10 degrees... and trout will feed quite happily at 10 - 20 degrees

Could probably keep it between that range if you pump during the day.... can't see the tank temp getting above 20 degrees during winter....

This is why I was suggesting the radiant chiller for the cool system and the solar water heating for the hot system.

Trick being (I'm not sure if this was understood) the chiller/solar heater (it is only being used as one at a time) has a coil on the roof or where ever gets good sun or clear sky exposure and an insulated tank of some sort. When in use as a heater, the water is pumped through the coil during the day when it is getting sun exposure thus heating up the water stored in the tank. When in use as a chiller, the water is pumped through the coils at night only thus cooling the water in the insulated tank.
Now here is the important part, You are not doing the exchange with the AP water while the heater or chiller pump is running. You are storing that thermal potential until the opposite part of the day and doing the exchange when it is most needed! So you are using the chilled water to cool your cool system during the heat of the day in summer or you are using the heated water to warm you hot system during the cold of the night in winter.

It might not be enough to really keep the cold system really cool but it should help.

Of course I suppose it might be possible to run a solar heat collector that could power an ammonia refrigerator for cooling but I don't know very much about that.

The biggest problem i see is no matter wether you insulate your tank or not is as soon as you pump to grow beds filters ect they are like a giant heat sink . As for heating 2 150 watt heaters will use lots of power with a surface area of 1/2 sq foot your 12 meter sq grow bed cooling or heating all the time just does not add up i find it better to go with the flow and have trout and silvers [trout will grow out over winter then cull and freeze] granted silvers dont eat over winter but what ever size they finished at the start if winter they dont shrink thats what they start next season so every second season you cull silvers. I am setting up 4 - 1000litre containers all running of the same water 2 for 100 trout and 1 for year old silvers and 1 for adults

TC

Earlier link viewtopic.php?f=8&t=2244&hilit=water+coolers

Chappo, love the ideas but suggest you break them into 2 separate projects and have different threads on each (Hot/Cold)

What is happening is that ppl are commenting and the suggestions seem contradictory because of the different circumstances required.

I think the best way to tackle it then would be to extend the growth period first, then see if it can made to work on a full 12 month period - to do this you really need enclosed areas for fish tanks, perhaps work on BSF and RSG filters to rid the system of those nastiescalled the NO2,NO3's - this would help in minimising heat loss through the GB sinks.

EllKaybee ,, Thanks for comments. Yes , encloser ( Insulated shed) will be a requirement for the warm water fish and warm water bio-filter.
I understand your thinking on splitting into two threads , but what I was hoping for was ideas that suit a dual system. If I split the thread ,, we will just get the same regurgitated ( although very good ) information.
Already TClynx has pointed out his thermal idea and in fact it could be used as a heater and a cooler.
Rupert has already pointed out about the beds being a major cold sink at night and a major heat sink in the day ( this has me thinking about pumping beds with warm water system in day time and a switch over to pump them with the cold water system at night.
I must hunt down some solenoid valves , two pipe in and one outlet.

Cheers and thanks everyone for the input.

Right now I'm pretty busy with a major house extension and working 6 days a week , but I hope to have a small test system in place within a month.

OK , thermals for the cold system area ( south side , behind a wooden fence) have been stable 15-18C , throughout several days and times varying from morning / afternoon and night. Continued testing would be fruitless , I have a stable temperature within the desired parameters under 21 C / , ideal 16-18C.Temperatures for the next 3 or 4 months will only get lower and still within optimal range.

Works will continue on the testing ideas for the "warm water" system. Challenges to keep the system around 23 C will increase over the coming months . Maximising thermal additions during the day and minimising thermal losses at night will be the keys.
Grid electricity will be used , but I'd prefer to use as little as possible and to maximise it's usage during "off-peak" times.

I had very little spare time today , so just managed a quick experiment ..... two buckets of water both filled with tap water today at 4:30pm ( 19 C ), bucket one not insulated , bucket 2 insulated ( very badly ) top sides and bottom. Just looking at the ability of this type of insulation to prevent heat loss. I know it is EXCEPTIONAL at stopping heat getting through the roof into my new house extension and another bonus is that it's insulation properties are not effected by water ( I don't think they mean UNDER-water).....,interesting.

So , it's back to my beer until the buckets have time for a temperature differential to show.

Well it's VERY cold night tonight in Sydney town,, cold is a relative term but for an April night is is COLD.
Back to the buckets ,, yep i wasn't going to wait any longer ( impatient person I am ).
Bucket 1 , uninsulated has already dropped 4 degrees , it's at 15 C .
The ( poorly, poor by applicatioin not by quality) ) insulated bucket #2 is still at 18 C , representing only a 1 degree loss.

next test ..... heat 40 litres of water to 28 C ,, add into the two buckets and see what happens.It's obvious that the uninsulated bucket will cool to around 14 C quite quickly ,, but what I want to see is how long the insulated bucket can hold the 28 C water input at or above 23C.

Yep couldn't resist ,, one more test before bed .....,10 C ( air temp) now ..... very cold for an April night.
Uninsulated tank now 12C ,, about what I expected,..... but insulated tank still near 18C , poorly applied , good quality insulation is working better than I expected.
Further testings at these temps a waste of time , at least we have now know we have a very good heat insulator.

I'll make the 28 C water now as I'm not sleepy and at least some pleliminary results can be assessed..

What kind of Insulation is this you are talking about. Do you have any links or pictures?