Heating Water

[Two Jay]

How are you, Aquapons, heating your water?

[Sylvia Bernstein]

I just use aquarium heaters. 200 watts heats 50ish gallons, so you just go from there. Easy, readily available, but definitely not the best way to heat a large body of water. If I could wave a wand and install whatever I wanted I would install a geo-thermal system in my greenhouse and heat the water using heated water pumped in from the earth...but that is pretty pricey!

[Nikki]

I have been wondering the same thing. We are just starting out and will be going pretty basic initially. Pretty much, we'll be starting with the old fashioned fish in a barrel...probably catfish. Beyond painting it black and putting it in the sun, I have no other ideas besides the water heaters in heating the water. I would definately be interested to hear the other ideas out there. Something economical and sustainable.

[Wolfenhawke]

There are a couple of green methods but need some real life testing. One is to store heat in a tank that is heated from solar piping. Need to experiment with solution in the tank that stores the heat. Something with a high specific heat. You know, potatoes keep their heat for a long time, so I was thinking of a starch solution, with a preservative like formaldahyde to keep it from going bad. You would use pipes in that solution to get the heat back out.

Second method could be car battery with solar panel. My thinking is that in my area, I need at most 6 hours per day for night time heating without recharging from the sun. The big 1000 watt heaters are recommended for 160+ gallon tanks. So, that is 1kW*hr * 6 hours or 6kWHrs. At 110V that's 54amp hours of charge. Let's triple that for losses in the inverter and others, and we get about 160 Amp hours of charge. This is within the charge holding capability of a battery. Problem is the charging. Even with the high end solar panels that seems to be 3 large panels at 10 hours of light to charge up. Maybe solar charging in addition to mains charging.

Anyway, needs some field work and testing....

[Two Jay]

I plan on incorporating Solar, sometime in the near future, somewhere in the greenhouse. We are leaning towards biomass heat - corn, cherry pits, wood pellets etc, hooked to a boiler to heat the FT. One question I have with this method is, do we run hydronic heating tubes such as Pex in the FT or do we run cool water into a water heater, of sorts, and jet the hot water into the FT? Does that make sense? Anyone have experience with this? The FT's are approximately 6400 gallons, combined, plus a few DWC systems that are approximately 3300 gallons...so a bit of water.

Wolfenhawke said:

There are a couple of green methods but need some real life testing. One is to store heat in a tank that is heated from solar piping. Need to experiment with solution in the tank that stores the heat. Something with a high specific heat. You know, potatoes keep their heat for a long time, so I was thinking of a starch solution, with a preservative like formaldahyde to keep it from going bad. You would use pipes in that solution to get the heat back out.

Second method could be car battery with solar panel. My thinking is that in my area, I need at most 6 hours per day for night time heating without recharging from the sun. The big 1000 watt heaters are recommended for 160+ gallon tanks. So, that is 1kW*hr * 6 hours or 6kWHrs. At 110V that's 54amp hours of charge. Let's triple that for losses in the inverter and others, and we get about 160 Amp hours of charge. This is within the charge holding capability of a battery. Problem is the charging. Even with the high end solar panels that seems to be 3 large panels at 10 hours of light to charge up. Maybe solar charging in addition to mains charging.

Anyway, needs some field work and testing....

[Joseph Orlando]

For those of you using electric heaters. I will be starting with 1200 to 1500 watts to heat a 300 gal tank. However, I ran into an informative article on tank heaters. In the article it says rather than buying a 1500 watt heatter it is better to buy three 500 watt or, even better, five 300 watt heaters. The reasoning is that in case there is a failure in one heater, the others can pick up the slack until it is repaired or replaced. The are two common problems with heaters. One is total failure (no heat), the other is getting stuck open (too much heat). In either case, the other heaters will either put out more heat to compensate or lower their heat to compensate according to the temperature picked up by the controller sensors. I just thought that made a lot of sense.

JoeJ

Sylvia Bernstein said:

I just use aquarium heaters. 200 watts heats 50ish gallons, so you just go from there. Easy, readily available, but definitely not the best way to heat a large body of water. If I could wave a wand and install whatever I wanted I would install a geo-thermal system in my greenhouse and heat the water using heated water pumped in from the earth...but that is pretty pricey!

[Joseph Orlando]

Ernie,

Good point! And yes! The design does plan for a single controller with multiple plugins.


ernie "W/ a controller, all the heaters are turned on to the max setting then plugged into the controller, which uses a better temp sensor than any of the heaters. The controller turns them all on and off at the same time as needed. The wear is spread across all the heaters."

[dano]

I'm using an indoor system, and have a water bed heater under one of my tanks [it really doesn't do much good] then I found by decreasing the time of my exhaust fan I can bring up the room, and tank temps by saving power instead of using power. I'm running the exhaust fan into my forced air heating ducts of my house. This allows me to recoup a little heat energy from my power use in the basement.

[TCLynx]

I've quit heating the water.

My first two winters, I had tilapia and a greenhouse or more like a cold frame over my systems. The first winter (2008-2009) was kinda a cold one for here and the water temp got down to 55 F even with my Solar pool heater and heat exchanger in an old freezer chest so I wound up having to run a hose from the hot water line for my washer out to the system and dribble hot water into the system overnight to keep the tilapia alive for the last two freeze nights that winter. We had already been making a point of drying the laundry overnight so I could run the dryer hose into the greenhouse to provide some extra heat to the air. I was not willing to run pond heaters into my tank. I probably could have simply overflowed my system by opening the top up valve since well water here comes out of the ground at over 70 F but I wasn't willing to waste that much water on a nightly basis.

The second winter I kinda gave up even through I still had the "greenhouse" I already knew the solar heating wasn't enough to get through more than one cold week and this past winter was really cold for here. I gave away as many tilapia as I could and those that didn't make it became chicken snacks.

Over this past winter I learned that catfish can easily survive sub 32 F water so long as they are advanced fingerlings by the time you subject them to that.

Guess what, I'm not bothering with heating my water anymore. I just grow catfish now. Granted, I'm in a sub tropical location and I realize those of you in a really temperate climate will have to do something to keep the pipes from freezing solid (I grew up in Michigan, I know what a real winter is.) Now over on BYAP Monya mentioned getting a heat pump like for a swimming pool and how it has worked really well heating water for his system. Has a titanium heat exchanger (even the stainless steel ones would corrode so titanium is a better choice with a fish system.)

Just a note for those heating water above air temp in a greenhouse over winter. If the air is cold and the water warm, you will have lots of evaporation and then condensation on the inside of the greenhouse which will block even more of the limited light during winter and might even freeze the greenhouse door shut. So beware. Also, if doing flood and drain and the air temp is really cold around the grow bed, then every time the growbed drains and the cold air is sucked down around the media it will chill the media and then when the grow bed floods again, it will in turn chill the water. Grow beds are rather effective heat exchangers at bringing the water closer to whatever the air temp is. So, some heating of the air or space in the greenhouse may be more important over night than one might think, at least if you do flood and drain.

[Joseph Orlando]

Yeah...I'm in Virginia and I'm expecting some really cool temps this winter. I have basically the same set up as you describe,TCLynx. One diffeence is my tanks will be insulated with 2 1/4 inch rigid foam with a top of the same mterial. The grow beds are constructed of the same material and I'm making hoop covers with clear plastic for each one. From what I understand, smaller fish will weater the colder temps better than grown fish. So the object with the insulation and hoop tops is to contain the warm water to the least amount of airspace possible. Then, to harvest the Tilapia before wnter sets in ( filet and freeze) and start my growout through winter with fingerlings.


cite>TCLynx said:

[TCLynx]

Joseph Orlando said:

Yeah...I'm in Virginia and I'm expecting some really cool temps this winter. I have basically the same set up as you describe,TCLynx. One diffeence is my tanks will be insulated with 2 1/4 inch rigid foam with a top of the same mterial. The grow beds are constructed of the same material and I'm making hoop covers with clear plastic for each one. From what I understand, smaller fish will weater the colder temps better than grown fish. So the object with the insulation and hoop tops is to contain the warm water to the least amount of airspace possible. Then, to harvest the Tilapia before wnter sets in ( filet and freeze) and start my growout through winter with fingerlings.


cite>TCLynx said:

No actually, fingerlings don't necessarily survive cold better. Now this all depends on what kind of cold you are talking about and what kind of fish. For instance, if you are talking about a completely unprotected ornamental pond in Northern Michigan that freezes over completely in winter, The smaller the goldfish, the more likely it is to survive. Remember you can have completely mature small goldfish since they just never stop growing till they die. Anyway, the smaller fish in that situation survive while the big ones die because the gasses that build up under the ice can't escape the the bigger fish suffer more because their greater respiration.

If you are talking about just cold water (not freezing over) and really small fish. Small fish don't have much in the way of fat reserves and most fish can't eat when the water is cold and therefore small fish often can't make it through the cold weather because they run out of energy and starve to death.

I know my catfish can survive in water below 32 F (provided it is moving enough not to freeze.) However, very small fingerlings in such a situation had about a 50% mortality rate.

All my small tilapia died when the water got down below 50 F for a couple nights. Also, even if tilapia might survive water down below 55 F, I have been told that if the water gets below 53 F it does in their immune systems and they are not likely to survive long term as they are wide open to opportunistic infections after getting a chill.

Tilapia don't eat much until the water is up over 70 F while catfish keep eating some down to below 60 F and so far as I can tell, the catfish are quite hearty even in the heat so long as you provide some supplemental aeration and keep the water quality good.

[Joseph Orlando]

Well, actually, I was talking about exactly what I described in my post.

However, I do remember one year a long time ago I had just moved into a lakehouse on a beautiful pristine lake. My second night there I caught a catfish fishing from my dock. Knowing I had someone coming to visit that weekend I took the catfish, whole and put it in the freezer. It was in there overnight. The next day, as a joke, I filled the bathtub and put the frozen 5 lb catfish in the tub, knowing my visitor would want to shower after the trip. After my guest arrived, we talked over some coffee for about an hour and then, as I expected, requested the shower. I waited for the scream and got exactly what I wanted....I rushed in as though I was surprised and wound up being more surprised than my guest. The catfish was alive and well splashing around wanting out of the tub!


DIV>
No actually, fingerlings don't necessarily survive cold better. Now this all depends on what kind of cold you are talking about and what kind of fish.

[Sylvia Bernstein]

Great story, Joseph! We did something similar to my father with a giant bullfrog in the shower...but it wasn't frozen ;-)

Joseph Orlando said:

Well, actually, I was talking about exactly what I described in my post.

However, I do remember one year a long time ago I had just moved into a lakehouse on a beautiful pristine lake. My second night there I caught a catfish fishing from my dock. Knowing I had someone coming to visit that weekend I took the catfish, whole and put it in the freezer. It was in there overnight. The next day, as a joke, I filled the bathtub and put the frozen 5 lb catfish in the tub, knowing my visitor would want to shower after the trip. After my guest arrived, we talked over some coffee for about an hour and then, as I expected, requested the shower. I waited for the scream and got exactly what I wanted....I rushed in as though I was surprised and wound up being more surprised than my guest. The catfish was alive and well splashing around wanting out of the tub!


DIV>
No actually, fingerlings don't necessarily survive cold better. Now this all depends on what kind of cold you are talking about and what kind of fish.