Heating options for fish tanks

[kellenw]

those kind of heaters will only run about 6 hrs without attention

You bring up an excellent point here. You can reduce that need for constant attention by fitting an autoloader and a storage hopper to the system, but those solutions can be quite expensive and somewhat difficult to properly calibrate when first setup or when changing fuel types (ie. changing from a bio pellet to wood chips or corn cob) due to the different burn rates associated with each fuel type.

[Kaduda]

I'm looking at a biomass boiler for my project, though my backyard is 320 acres...lol...

I'm planning on using it to heat my house, shop, chicken coop, and greenhouse...So a bigger boiler system for me would fit in nicely...

[arachdog]

If I was building one I would design it something like the Imbert wood gasifier. http://www.gengas.nu/byggbes/10.shtml
You can make the hopper as big as you like and all the wood (or whatever) just sits right above the fire and falls down on demand (provided its properly sized so it doesn't bridge and jam up). It can't burn in the hopper because there is no oxygen. The only thing you need to add to the Imbert is a blower (since its not running an engine) , some steel piping to pump your water through and a combustion chamber with some more air vents to fully combust the gas, created at the hearth. Then if you wanted to get fancy you could hook up some sought of temperature feedback control to your air inlets. Sounds like it could be knocked up in its basic form in a weekend if you had all right materials and equipment.

[mornings]

Quite aside from the way we heat our tanks (I don't have fish but I still have a need to keep the water on temp for plants and worms), I'm finding the heating of a greenhouse is quite complicated (I am assuming, of course, one would only heat water if one has a greenhouse).

The plants (and worms and/or fish) would seem to care only about the water temp. However, if the air temp is lower than that of the water (where lots of water is available as in a aquaponic system), then I get evaporation and then condensation. The condensation cuts down on the light and, hence, the temp of both air and water, which in turn effects plant growth and the ability to uptake nutrients (pollutants to the fish and/or worms).

I have a subterranean heating system. It works really well in that it can capture a major portion of any excess heat in the GH for night use. However, at a certain combination of lesser light and outside temp, it is no longer functional (I live a rather poor solar area -- in some even colder areas it works well because sunlight is more available).

What is interesting is that only a small input of energy (heat) tips me back to a drier, more functional GH -- if I can keep air temp at or slightly above the water temp, then I get more light and the subterrean system keeps everything working and growing.

As stop gap, I'm putting together a 35 gallon (154L) drum wood heater. I'll put a metal tank on top of the heater. I'll connect a thermostatic controlled (65-72F[18-22C]) pump to the tank to pump hot water through a closed loop within the tank. The heater should heat both air and water. The subterranean system should then keep the whole system stable.

Anyone else use a subterranean heating system? Comments?

m

[doc pyro]

Hi all I'm backtracking a bit since i have just read the thread but I know a little bit about paints, so my 2 bobs worth, with normal house black paints will be stripped if they are in contact with hot water above about 40ºC. Which would occur if you painted the corragated steel.
Also Water based paints contain biocides and surfactants (soaps) that could be toxic to fish unless washed out first.
Oil based paints do not have biocides so they may be a bit safer but they will strip as mentioned above.

Also Coolant generally use Ethylene Glycol which is toxic and not Propylene Glycol which is not so bad.

[beelove]

If I was building one I would design it something like the Imbert wood gasifier. http://www.gengas.nu/byggbes/10.shtml
You can make the hopper as big as you like and all the wood (or whatever) just sits right above the fire and falls down on demand (provided its properly sized so it doesn't bridge and jam up). It can't burn in the hopper because there is no oxygen. The only thing you need to add to the Imbert is a blower (since its not running an engine) , some steel piping to pump your water through and a combustion chamber with some more air vents to fully combust the gas, created at the hearth. Then if you wanted to get fancy you could hook up some sought of temperature feedback control to your air inlets. Sounds like it could be knocked up in its basic form in a weekend if you had all right materials and equipment.
I love this idea. If you added a generator in place of the blower you could provide power and still heat your tanks with heat exchange. Wood chips are free in my neck of the woods.