Backyard Aquaponics
A place to discuss aquaponics

out here it's now freezing -6°C
huge problems
this leads me to question a lot of my assumptions concerning system design where frost can occur
everything grounds to a halt
annoying
a search on 'frost" doesn't give any results
maybe we can exchange thoughts on this thread?
frank

A greenhouse is the only thing I can think of. Power costs of attempting to heat is a big issue though. Using geothermal underground heat storage for heat during the night is cheap if you do it while building the greenhouse. I seen people in Canada that have built them and are adding no power except for the energy it takes for the small recirculating fans.

Plastic barrels are used for headers and plasict drainage pipe is used to interconnect them. They are then back-filled with gravel. Warm moist air during the day is blown in from the top of the greenhouse. It consenses the water and stores heat in the gravel. At night the warm air now comes from underground and heats the greenhouse. It acts also to cool the air during the day keeping the greenhouse from overheating.

Maybe this site will interest you Frank ... http://www.hobby-greenhouse.com/FreeSolar.html

I know that locally some farmers use irrigation to prevent frost damage to the fruit or plants. Frost only kills when the plant is hit by the sun rays. Irrigation turned on at 4am in the morning melts the ice in the sap and so prevents freeze burn when the sun rises. Don't know how helpful this is to you in your situation. Here is a guy who also talks about it.... http://www.greatncwines.com/?p=157

I know there have been lots of discussions about heating and greenhouses for climates with cooler temperatures though I doubt "frost" is one of the primary terms mentioned.

I know in my sub-tropical climate, sinking my fish tank into the ground to benefit from the geo-thermal coupling has been great for me. Probably not quite enough to make keeping tilapia outdoors here without supplemental heating very easy but I know my water temperatures have been generally better than another system not too far from me and he has his fish tanks inside a building.

The viability will greatly depend on the fish you wish to raise and the veggies you want plus the resources for things like greenhouses. If you only get occasional frosts and are happy raising fish that can survive it, then there are plenty of crops that will survive it and you might not need to do anything special. If your climate leaves you freezing for weeks at a time and, you are planning on tomatoes and tilapia, well that's a whole other story.

So what are your plant and fish requirements? What does your climate usually give you?

everything is in a greenhouse (unheated)
alas no sophisticated energy buffering yet, due to limited budget
solar is planned, but not installed

at this moment I have not much planted (came too late for that), so there is not much to lose there
nor do I have many fish and these are not threatened yet
fish tanks are deep enough (IBC)

in a certain sense I feel "lucky" to have to pass this test now

I am also glad that my thoughts on passive aeration led me to install open gutters rather than PVC pipes everywhere I could
most of the PVC pipes would have burst by now

The problem is mainly with the flexible hoses I use to drain the growbeds and the siphons

these siphons cause the water to stagnate between flood and drain, so the water freezes in the hoses and then of course in the growbeds
next the pump lines freeze because the water has nowhere to go

luckily they are all flexible hoses, so they don't burst (yet )

I am thinking of eliminating the siphons and changing it all to FFCD (Fast Fill, Constant Drain), so the water keeps moving

the floating rafts line I have installed parallel to the growbeds line so far poses no problems, though it is much more exposed:
there is a thin ice film, but the water keeps flowing

so at this moment the fish nor the plants are my real concern

the technical issues are

frank

hi
As stated above using irrigation before the sun rises is one way, others use smoke as well, I used to have orchids and frost was a major problem for them, and actually where I live now frost is a major problem, as my bannana tree
How much sun do u get during the day, I have plans of using a stem similar to a pool solar heating system, now it can be as simpl as black poly pipe and a storage tank collectiong hot water during the day and either maintaining the water temp in the tank and growbeds above zero during the night or running a seperate any frost hose on top of the hydroton on the growbed keeping the water circulating when the temp gets low creating a microclimate for the plants, suppose it depends on the size of the system and whats feasible and whats not, but this is the way im going to try, we have had 30 odd frosts in a row here where we live in NSW with 75mm-3 inches of ice in buckets of water laying around
Should I be putting fairy penguins in my FT?
Bree

fortunately frost mostly coincides with a clear sky, so while the nights are horrible the days are sunny too
in my greenhouse during daytime interior temperatures easily rise to +10- +15 °C with an outside temperature at - 4°C
some hours of this so far allowed to defrost everything by 6 o' clock in the afternoon, when the sun disappears

I absolutely agree with you on the simplicity of solar
but one should not really expect "hot" water during winter
I would be happy if it would compensate freezing at night

TMHO any anti frost hose should not be ran on top of growbeds, but on the bottom as heat tends to travel upwards
it will keep the roots warmer
and hopefully the plants too

running the hose on top would only heat up the freezing air, with little or no effect on the plants

my opinion

frank

True what u said about heat rising but with frost the idea is about protecting the the shrubbery above the growbed from the sunlight and cell destruction, depending on the hot water available to what extent u can heat, if u run the heating system in the bottom of the grow bed I am wondering if the growing medium will suck up all the heat and none of it really reach the surface and create the microclimate to protect the greenery, like i said depends how much heating medium one has at hand or a combination of both maybe ?

Bree

far out bree is that for real I am

Ok, so if you are having water freeze in your greenhouse, you do need to sort out some warming.

I agree that warming pipes or cables should be buried under the gravel or below the grow beds.

I can say that I have two of those solar pool heater panels on my roof and a small container in an insulated chamber. The water gets pretty warm during warm sunny days but I think I've only managed 110 F in that container. Since it is such a small container and only getting hot but not super hot, it isn't doing much for my system overall. I think for this method to be really effective, I would want to be heating a very large amount of water during the day to help tide the system over at night. If you can cram that greenhouse full of water containers to link to the solar heating, you will probably be far better on the thermal mass in general as well as storing the heated water.

If you switch over to timed pumping and avoid the syphons, you can also avoid pumping during the coldest part of the early morning and perhaps avoid chilling the water as much.

About the open topped water distribution system, that might be where you are loosing huge amounts of heat from the water. The more water surface you expose to air, the better aeration but also the quicker you change the temperature of the water. If you could put some covers over those troughs for the cold nights, you might have less water freezing. Water in a container exposed to a clear sky on a cold night is gonna loose far more heat than that same container with a minimal cover or even the container under a cloudy sky at the same temperature. (a solar cooker will turn into a radiant chiller when aimed at clear sky at night.)

If you can warm up the gravel and water enough, you have more beneficial thermal mass to help keep the entire environment of the greenhouse warm.

That said, I suppose the question is priorities. If the water in the bottom of the grow bed is managing to freeze, I doubt the plants will care much one way or the other about the frost to the foliage. In somewhat mild climates and in ground plants, the challenge is to keep the severe cold from injuring the top part of the plants (in these mild climates a simple frost isn't going to freeze the ground.) When talking about container plants in a greenhouse where flowing water is managing to freeze in troughs or the sitting water is freezing in loop siphons between drain cycles, I fear the cold is a bit more severe than simply spraying the plants with water or using a smudge pot is gonna fix.

Question about the greenhouse, is it well sealed at night or when it gets really cold? If there is wind blowing through it, keeping your heat overnight is gonna be tricky.

On trick I've been doing with my "greenhouse" on the coldest freeze warning nights we get here. It's close enough to the house (and the dryer) that I have run a dryer hose into it from the house. I make a point of doing a really late night load of laundry on those nights so I can run the dryer and help warm up the air in the green house a little bit that way.

Thanks, TCL for very valuable tips and tricks

especially like the dryer tip

as it is I did some washing and drying today and I was wondering how I could recuperate all the wasted energy

unfortunately the distance between washing room and greenhouse is prohibitive

maybe next year (only a few days away ) I will move the dryer into the greenhouse. excellent idea.
win win

frank

What the frosts? Yes that scenario was a few years ago now at my old place a couple of kilometres away in the same area, this year we had a dozen or more frosts and anything left out was frozen, weather here close to the mountains seems to do it, sunny here today, look at yesterdays weather.
Have had summers of 40 odd degrees constantly as well, I remember when we built one house we put the tin roof on under spotlights at midnight as it was to hot during the day 48 degrees or something stupid like that
We get extremes

Earth-coupling will moderate the water and air temp significantly.

Some sort of greenhouse to reduce exposure to cold sky.

Tight greenhouse to reduce flow of cold air (but you will tend to have trouble with still, humid air and plant problems. TYpical solution involves fans)

Heat pump like Synaptoman uses: warm your water for fast growth of most fish and to protect from frosts.

Generator inside a greenhouse with waste heat going to fish tank? Use electricity light plants for better growth. Residual heat at night should help prevent frosts.

A propane-powered radiant heater can work wonders, especially if it is only a few nights per year.
Something like http://www.amazon.com/Mr-Heater-Propane ... B00005LEXJ or one of the type used at outdoor restaurants on chilly evenings.

Good luck, mate!

My greenhouse is insulated on ceiling and wall opposite the sun. I do have autovents above the windows. I have 12, 55 gal drums of liquid for thermal storage under the grow beds and another 550 gals in fish tanks. Still my fish water gets below 50 deg. F. To cold for fast growing food fish like talapia.
I have a 50 gal hot water tank in the greenhouse that is heated by a solar collector that is inside the glazing. It will warm one tank during sunny days to 55 deg or so from 50. I am working on adding another collector (3ftx7ft.) and mounting both outside the greenhouse. If that doesnt do it I plan to make panels to cover the glazing and prevent heat loss thru the single glass panes. I hope to get the H.W. tank water warm enough to circulate to FT and keep warm water fish thru the winter.
At 50 deg. F the goldfish do well, eat and grow. So the plants are getting plenty of nutrients. My napa cabbage, lettuce chillies, basil, and tomatoe plants are thriving. Now we are in a warm spell so hope some of my tomatoes will ripen on the vine. My air temps in the G.H. have not dropped below 40 deg. F.
My last resort is to use the electrical element in the H.W. tank to boost heat and then ciculate it to the FT on a thermostat control. Your solution, Hygicell, may be to install a used electric or gas H.W. tank and heat it any which way you can using the built in element to supplement and circulate that to FT on demand. The mass of warm water in beds and FT will
warm the air. Many solar collectors are copper and cant ciculate direct to FT and you need the heat most at night hence the HW tank.