Time I chimed in here, been quiet on the board cause I'm busy.... I have never heated with anything BUT water elements. I started out in a 5gal bucket with a 1200W heater dangling from an extension cord into the bucket. I keep saying I'm rebuilding my entire system, but I have literally done little to nothing in that respect. I have had as much as 10,000W of heat in a 55gal drum. Every batch I made in the later part of my adventures was heated to boiling.
Something to keep in mind, a WATT is A WATT is a WATT it does not matter what the voltage is, 50W at 12V is exactly the same as 50W at 480V what differs if the amperage to create that same wattage. 50W at 12V is a little over 4Amps, whereas 50W at 480V is only 0.1043 Amps
What does that mean????
The lower voltage elements will require larger wire to push the same wattage as a high voltage element of the same wattage.
A 5000W element will draw just over what a 12GA wire is NEMA rated for, but will work on short runs ie less than 10'. 12GA wire is actually rated for up to 40 AMPS in enclosed cabinets etc, (think inside closed industrial equipment cabinets, internal wiring in equipment and etc)
I run 5000W elements in all of my setup and they all are wired using 12GA "Carol SJ" service cord. The high heat and oil does cause pretty rapid deterioration of the submerged wire and causes me to have to periodically cut the end off and rewire. I boil my batches until the boiling stops. Sometimes that's thirty minutes, sometimes that 3 hours.
Cost I have forgotten, but it was minimal. For example, lets say I pay 0.15 a KWh, that's 0.75 an hr to run a 5000W element, I have heated for as long as 8 hrs. so that 8hr run cost me 6 bucks. I don't remember exactly what I pay per KWh, but I know it's close to 0.15
The problems with heating an entire batch at once are numerous. You loose an enormous amount of heat from the top and sides of the drum. You waste a lot of heat maintaining that batch when you only need to heat what is going through the fuge. Hot oil burns,,,,lol, I have a ruined pair of glasses that saved my eyes from a hot oil splash.
Fire hazard rises exponentially as heat rises, and I have flashed over more than one batch cause I'm absent minded and forgetful. I have oil stains all the way to the ceiling of my barn from a flash-over in a semi enclosed drum where the repetitive flash-overs shot oil up to the ceiling through the bung holes. I came home from town one day to hear a repetitive whoomp whoomp with a really slow rhythm. It was a batch flashing over, running out of oxygen, and repeating when the fumes exhausted and it drew enough fresh air through air convection to do it again. With each Whoomp it shot several ounces of oil up to the ceiling as I witness upon walking into the barn.
Last but not least, oil cannot carry the heat away from the element as fast or as good as water does, so they don't last long. even the ULWD ones burn up pretty quick but still last considerably longer than the cheap ones, or at least they do at the temperatures I heat to. I have noticed the 120V ones lasted a lot longer, I'm sure it had a lot to do with the fact that they could only heat the oil so much, so there was a large enough temperature differential between the element and the oil for the oil to carry the heat away from the element fast enough. Something I have toyed with is using 4 5000W elements wired in series parallel to still only produce 5000W, but do it over a much larger surface area.
In the end, I will be using one or two coffee maker heaters to heat my batches, they will only draw about 1500W and will only be heating a very small amount of oil at a time, but that method will only work using a motor driven fuge that is drip fed. I briefly played with a home made inline heater but dropped the idea because it was bulky and unpredictable in the way I wanted to use it. If I took the time I'm sure I could make it work.
