A Community and Forum For Aquaponic Gardeners
Heating Greenhouses, Fish tanks and Float tanks
NAI - The Ark - Passive solar Greenhouses - Solar Aquaculture - Bioshelters
I have posted this before.
It still amazes me how many times we have to relearn the great lessons that others before us have taught. I suggest we start talking about how Passive solar Greenhouses can maintain their Fish and Plants in Very cold climates. Take a good look at the work we did at NAI and more important what is the current configuration. The fish tanks heat the greenhouse and the house.
Also Bruce Fulford designed, built and operated a Composting Greenhouse. It had NO FISH tanks to heat it.
Bruce today
see pdf below - yes this information is 40 YEARS OLD. I am sure there have been many since then.
Check it out and if you want to see a commercial version check out Solviva that was on Marthas Vineyard. Also check out the book about Solviva. I was there also
Lets get this information out to our Aquapons in the North.
Some other interesting links on the subject
My next post will be about what may be possible with Solar Cooling.
NAI art bioshelter home today.
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compostheatedgh.pdf, 154 KB -
compostgreenhouse.pdf, 8.4 MB
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arkhouse.pdf, 83.2 MB
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Replies to This Discussion
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Permalink Reply by Rob Torcellini on
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A lot of good stuff here. Composting greenhouses have been debated a lot on some of the other groups...lots of pro's and con's. I'll stick to some of the con's for now. Some of the issues I have are:
1) A greenhouse isn't able to produce enough plant waste to be self-sustaining with the heat the compost would produce. The means you usually have to bring in outside waste such as a lot of plant waste or animal manure. The can bring in outside bugs and diseases that are difficult to control.
2) To produce enough heat from compost, you need a lot of it. Unless you can put a composting pit under the floor you will lose valuable growing space. Most places may have problems trucking in enough materials.
3) Here in CT, during the winter, the temperature can be 15 degrees (or lower) into the 40’s and sunny during the day. The issue with composting is that it gives off a fairly consistent heat. On a sunny day, the solar gain is enough to heat the GH and there is no need to draw heat from the compost. (I’m aware you can also put active tubing through the compost and blow air through it to extract heat at night – labor intensive to set this up)
One “technology” that I’ve been researching is the biodigester. I haven’t tried it myself, but there are many large dairy farms that use them to produce enough gas to generate electricity for their farms. The waste water is filled with nutrients that is then spread back on the fields. The bio-reaction usually needs to be started with manure, but once established, it can be sustained with plant waste. A couple of thoughts on how this could be used for a greenhouse:
1) The digester tank can be buried outside – keeping valuable space available in the GH.
2) The digestive process kill of most pests and diseases.
3) The gas produced can be stored and burned for heating when needed.
4) The water coming out of it could be fed back into the AP system which is filled with nutrients
5) Same problem with compost….you need a lot of it!
That’s about brain has in it tonight….I look forward to some interesting replies! -
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Permalink Reply by Darrin Charbonneau on
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So many ideas..so little time...
The composting idea doesn't appeal to me with my limited back yard space and compost.
Digester tank is a great idea but more applicable to commercial operations.
"a penny found is worth two earned"
Before creating more heat, wouldn't it be better to first invest in retaining as much of your natural solar heat as possible?
Heating during winter is the single biggest design challenge for my new greenhouse.(similar in size and function to Rob's)
After reading Michael's posts I've decided to follow the suggestions of insulating the North wall fully and the lower 3' of the rest of the structure. Double glazed South facing windows, double glazed end window, sealed storm door.
It will look more like a shed with lots of windows and a clear roof.
(planning on using the cheap 2" styrofoam)
I was hoping to have a sealed Lexan roof with venting out the end walls.
I know that heating the 270 gallon fishtank will create extreme humidity.
I would like to grow Tilapia but will switch to trout if the humidity is unmanageable.
Considering heating fish tank with solar vacuum tube system?
http://www.youtube.com/watch?v=xsx7BX0l5uQ&NR=1&feature=fvwp
also found this on youtube... solar furnace
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Permalink Reply by M Cosmo on
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Ok it is time to start working heating the Greenhouse. I am evaluating several solutions. The first conserver. I found this product and I have checked that it is fish safe. PoolDisk. It is LDPE 4. They come in 48" and some eval mini size. I have asked for a few for eval. Take a look and think if it would work for you.
Here is some info from their site.
"PoolDisk helps you save money by reducing your pool energy losses. With PoolDisk's technology, evaporation losses are reduced. Your pool stays warm and water loss is reduced. PoolDisks will typically reduce energy costs by 50%.
PoolDisks are simple to use and attractive, The disks do not require inflation, nor can they ever puncture, leak or deflate. PoolDisks are made of US Coast Guard approved flotation material, with a estimated outdoor life of 5+ years. PoolDisks are engineered to grip your pool's surface, staying in place even in gusty winds.
click to see larger
New Video: PoolDisk Installation & Removal
PoolDisks adapt to any shape pool, and typically cost less than half of a roll-up cover system.
The charcoal/black disks are UV protected and remarkably efficient at reducing evaporation. A PoolDisk is 48 inches in diameter, 1 inch thick, covers an area of 12 square feet and weighs only 26 oz."
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The next part of the plan is to evaluate the possibility of putting in an active solar heating system. Pool heating systems are very applicable for our use. Unlike active solar heating systems they are designed for the temp ranges we want for fish tanks. Take a look at this controller and see how it may apply to your situation. This controller also cools. The control unit I like is one of the Hayward units.
Here is some info on it. I like it because it comes in a kit with the diverter valves and is designed to work outside. "Aqua Solar®
ITEM # AQUASOLAR
Description
Conserving energy, reducing pollution and "going green" are in everyone's best interest. With Goldline Controls' Solar Combos, you'll be doing your part because solar controls are as environmentally responsible as they are high-performance and user-friendly.
The Solar Combos are bundled systems consisting of a controller, an actuator, a diverter valve and two temperature sensors. They maximize solar heat collection by monitoring the temperature of both your solar collectors and your pool. When your pool needs heating – and your solar collectors are in energy-receiving mode – the controller automatically diverts the water flowing between your pool's filter and gas heater and routes it through your solar collectors. There, the water is heated to a pre-set temperature, or until no more solar energy is available, at which time the gas or electric heater kicks in, using only as much fuel as necessary to make up the difference."
Yes you will have to hook it up to collectors but thee are lots of products you can use. You guys in the north should really be looking at this to heat your tanks and greenhouses. Just add a lot of water for thermal storage. By the way some of these control units are not that expensive. They range from 150 to 350 - Here is a link for one. -
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Permalink Reply by Paul Letby on
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Very cool links Michael. I'll have to let Bentley the compost guy know he's even more famous now. He and I are usually shooting emails back and forth once a week or so. What did you think of the Soap Bubble Greenhouse? I think it's an excellent solution in cold climates. I had a hard time digesting the insulating qualities of bubbles! R2 to R30 in minutes. I'm still learning about greenhouses, looking for perspective.
I bookmarked a bunch of those links. Very good stuff. -
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Well we went on to design a batch heater with a 55 gallon drum and a liner. This unit would be in an insulated breadbox cabinet. All from recycled material.
Now we are going to test a unit Ron found that is a feed tank heater and has a settable thermostat.
This is the unit and at a good price from this link. $99
Manuf site.
"The Tankside De-Icer clamps to the side of any stock tank and prevents livestock from removing the unit from the tank. The De-icer comes with an adjustable thermostat which allows the user to set the water temperature (raising the water temperature to encourage drinking, or lowering the water temperature to save electrical expense). The heating element has a large diameter for prolonged De-icer life. The lower portion of the heating element will keep the drinker ice-free. The thermostats on these models are replaceable. "
I can actually mount this right in my tank but Ron may have to use a separate tank as his fish tank is a plastic pool.
Total solution is $112. Then I could mess with solar at my leisure. -
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If you're in a colder zone, it's very difficult to store enough heat in water to keep a greenhouse warm at night. There's a few factors that can make or break a good setup.
1) Do you have enough space for that much water? About 1/5 of my floor space is covered with water tanks which take up valuable growing room. But it regulates the temperature well enough were I only need to run heaters from after Thanksgiving to late Feb. During Jan, it still will cost around $8/night to heat.
This is a 5-day graph is my greenhouse temps (in F). The blue line is the water, yellow is sunlight, red is outdoor, green & orange is inside. The first night, you can see the water temp going down, then when the sun comes out, my pumps turn on. There is a sudden dip in the temp as the water fills the growbeds then drain back into the tank. Then as the greenhouse starts to warm up, teh water tank starts to go back up. The second night the outside temps went down to 26, the inside stayed at around 40, but I lost a lot of heat in the water. On the 4th day, not much sun, so I wasn't able to gain any heat....
2) If you heat the same water that your fish are in (and of course going through your beds), your water is going to be warmer than the air. You'll have a terrible condensation problem with the humid air against the cold frame and glazing.
This picture shows the problem with condensation and it freezing. Many times the doors will freeze shut and it can be serveral days until I can gain access! This pic also shows the "heat extraction units". As the ceiling temp gets warm, instead of wasting the heat, I pump the cold water through these to help reclaim the heat. Works great!
I don't have any external solar heating. All my solar heat is from the greenhouse itself. I also have 2-1500watt electric heaters that run on the really cold nights. If you haven't seen them, you should check out my videos at http://www.youtube.com/web4deb and my blog at http://web4deb.blogspot.com. There may be some good details that may help! -
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Permalink Reply by TCLynx on
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Even in warmer climates, I found that I didn't gain a whole lot of heat by storing it in water (granted, since I wasn't willing to run fish water through my solar collectors, I didn't have as much water for heat storage.)
I expect anyone in a cold climate would be wise to insulate as much as possible. -
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