[NapaBavarian]

Just taking off on the water heater idea what if a water heater was filled with oil and fired up, then run the hot oil through the filters into a well insulated container to sit for the proper time. Of course I would run a course filter before I fill the heater to aviod the big stuff, maby an old shirt or something.

 

[Monte1]

Yeah, it would work. Remember though, one of the big reasons people use wvo is because of the lack of complexity and cost of the fuel.
Heating a barrel of wvo is not cheap using electricity. I have a friend who simply puts it in a black steel drum in the sun and lets nature take its course for a couple weeks. If you are interested in not having drums ow wvo sit around, maybe others here can give you some ideas. I too, am cramped for space and this "hobby" looks like it can take a lot of room.

 

[NapaBavarian]

That sounds like it would work well during the summer, I've also thought of building a waste oil burner, could burn the oil that has setteled to the bottom and is full of sediment for winter use, to heat the oil too, then use a coil. Also, coiled black hose in the sun to heat the oil for filtering might work.

 

[flyingisbest]

Napa, just a friendly heads-up, learn from my mistakes kind of post...I would strongly recommend NOT building a waste oil burner yourself. Been there done that, almost burned down a $100K workshop building, the things tend to "take off". Not alone in this experience either, they are just too uncontrolled and too unpredictable, not to mention require too much manual intervention to be worthwhile. ESPECIALLY when you can buy a real, purpose built, rebuilt to like new standards waste oil burner CHEAP. I bought a Shenandoah burner for $700. CHEAP compared to new. Mated it to a 320k BTU boiler, and now can heat 2 buildings for near free on waste motor oil from a friend's car repair shop. Clean Burn brand burners are even cheaper, at 600. Go to Whitten Enterprises, tell 'em Bill Kichman sent ya, he will treat you right, and you (man I sound like a SALESMAN) will be satisfied with what you get. I plan to run my boiler to heat my WVO for filtering. Let one waste product do the work to prep another waste product. Electric heat is too expensive for this use.
Hope this helps.
P.S. The bigger the boiler the better, as it helps with cleaning cycles. Waste oil requires you to clean out the boiler tubes or heat exchanger tubes (in air-air exchangers) and the smaller the boiler, the more frequent the cleaning required.

/ubbthreads/images/graemlins/tongue.gif I should charge $ for this advice /ubbthreads/images/graemlins/laugh.gif

 

[dOGhAIR]

Ok, I know there are some smart kids here. I run a 4800w 240 volt water heating element for less than half an hour to heat 42 gallons of wvo to 130 f. each time I make biodiesel. I do this in an uninsulated metal drum but I live in temperate northern california. I've read that reaching `150 f. and then settling is good for helping break any water in suspension, so a little longer may be in order but I think even as low as 80 or 90 f. would help in the filtering process. Is the math for 240v half of that for 110v?
.5 x 48 kw x .5 hours = 12 kwh
My rate fluctuates around $.15 per kwh because of the type of property my service is on, so I'm figuring $1.80 for my use.
Can someone confirm my math?
I run my pump most of the time that the oil is heating to circulate as I have a feeling that oil may be super heating at the element. Anyone know if this is really necessary?

 

[NapaBavarian]

Should be 24kwh, 4800 wats is 4800 wats no matter what the voltage, howerer the ammount ov energy in an amp changes (is a factor of) wats and volts.

 

[TimLaRanch]

[ QUOTE ]
Should be 24kwh, 4800 wats is 4800 wats no matter what the voltage, howerer the ammount ov energy in an amp changes (is a factor of) wats and volts.

[/ QUOTE ]

Um, not exactly. See Ohm's Law.

A 240v 4800w heater has a resistance of 12 ohms. If you change the voltage, the current will change, and since watts = current * voltage, the watts consumed will change. See Ohms Law for the simple version, along with a calculator.

It shows us that this heater, run at 120 volts, will produce/consume 1200 watts. This is because at half the voltage, you'll get half the current (1/2 * 1/2 = 1/4) and 1/4 the power.

<on edit>
Now comes the weird part. I don't know what the specific heat of veggie oil is (it's specific gravity is 0.92, which gives us about 320 pounds), but a 1200 watt heater is dumping about 4,000 BTU per hour, which would raise 42 gallons of water by about 11 degrees. In an hour. (One BTU will raise one pound of water one degree. 42 gallons = 350 pounds). This is nowhere near hitting 130 in 30 minutes, unless the specific heat of oil is some really oddball number, or the oil was already quite warm to start with. Like, 100 degrees or more. Or, there was significantly less oil than we thought. Or the heater really is running at 240. Or it's really a 120V/4800 watt heater.

Really odd. I'll ponder it some more... /ubbthreads/images/graemlins/shrug.gif /ubbthreads/images/graemlins/sleepy.gif

-T

 

[NapaBavarian]

I guess I was making the asumption that it was running on 240 volts since it was a 240 volt element, maby not everyone has their house plumbed tht way though /ubbthreads/images/graemlins/laugh.gif

 

[dOGhAIR]

Both of you have provided helpful reminders.
I am running 240v. I can't word this in a way that makes sense so I will leave it be. You are both right.
cheers

 

[TimLaRanch]

Dang. I shouldn't read posts that late. You're right, it's 4800W at 240, and you'd see that kind of temp rise in 30 minutes. Don't know where I came up with the 120v sub-thread.

Soooo....

4800W = 4.8Kw * .5(hours) = 2.4Kwh *.15($ per Kwh) = 36 cents per run.

-T

 

[sagebel]

I would keep the pump running. I was hoping by placing the element at the bottom of the barrel (welded on a bung) that convection would keep things mixing. I was wrong. Right now I am mixing with a stick but I am going to try a very large air pump and air stones on the bottom to do the agitation. We'll see how that works.

Scott