Oil tank heater

I have a 600 litre diesel tank that is stuck for 3-4 months of the year in a premafrost. This has obvious effects to the diesel as it gets to the point of gelling in the tank/lines. I intend to fit a tank heater and wondered if there is some way of working out how much energy will be required to stop this effect-I have several 3 phase heaters from a tank that previously held bunker fuel. These are very power full and I only have singe phase avalible. From basic tests I have done I have rewired the elements so they run in series thus ruducing there heat output - this will at least give me 3 heat ranges to choose from etc(these elements are about 5-6KW each phase) From what I can gather I shouldn't need a large amount of heat, just enough to keep it above about 4 degress and keep the fluid in the tank. What I would like to try and get right would be how many KW would be about right for this size tank with the ambiant temp around -18 degress celcius? This of course will be controlled by thermostates and a top limit control- how does one calculate this?
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You left out a few parts that would allow proper determination of a solution to this issue.... But it would appear that either:
1. The 150 gallon or so tank is insulated very well from the surrounding earth. If this is the case, it really shouldn't take much energy to keep it fluid. - or - 2. The 150 gallon or so tank is directly buried with no insulation from the surrounding earth. If this is the case, you might as well just dig the tank up, and put it in your garage. The alternative being that you will need to put enough heat into the ground to keep the permafrost melted to achieve your desired 39 degrees F. I would suggest signing up for the required 3 phase electrical service, as you're gonna need it. Don't forget to get that fancy digital "thermostates" that you mentioned controlling it with. - or - 3. Forget about wasting the electricity to melt the earth. Use it instead to provide the heat that burning the diesel slush would otherwise be providing.
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TSS had written this in response to http://www.thestuccocompany.com/hvac/Oil-tank-heater-17733-.htm : cdd,
My company, Thermal Stability Systems produces outdoor fuel oil protection systems that will solve your fuel storage issues. You can find information on our products at www.thermanstabilitysystems.com.
Let me know if I can help,
Eric
------------------------------------- cdd wrote:

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