mine takes 3 hours ?

[Rotary-Motion]

hi all

just checking a tool out on here, and my oil for 4 years cooking waste veg oil takes 3 hours give or take 5 mins, to 60c this calc says an hour 2 mins?

[Head Womble]

I take two minuets, sorry wrong subject 

[Rotary-Motion]

 

I take two minuets, sorry wrong subject 

crikey thats slow hahaaaaaaaaa

[greasemonkey]

I think that is theoretical. Are you getting heat losses somewhere, like through the floor? I seem to remember you have you tanks pretty well insulated.

[Tony]

Also water in the mix will slow it, as will any voltage drops on an extension cable.
For example a 3kw immersion running at 215v will only output 2.4kw.

3h to hit 60c is ages! Maybe time for some insulation?

[Rotary-Motion]

for this calc is it circulating via a pump aswell? mine is not. also the oil i heat has been bed sheet filtered with natural settle for free water out, and i pull from 8 inches up to get goodish oil to go in my pot for cooking. also it uses the standard thermostat (which trips in / out) and isnt set to be on permanatly say via a PID etc. my insulation round the tank is thick loft insulation and heavy duty tin fiol over that aswell as on lid (holds heat 3 days). with gradual loss of course.

does have 1 bad piont though, its on an extension cable to shed. 

i would expect that sort of time of 1 hour for water heating but dont get that with oil

[Tony]

Actually oil takes about 3 times less energy than water for for the same raise in temp, so it should heat 3x faster!

The calculation shouldn't be affected by pumped circulation, it's for static heating but the same should apply (a pump confuses things, as it may add extra energy or some may be lost through uninsulated pipework).

Have you got one of them plug in energy monitors?  It should tell you the voltage at the end of your extension and the power being drawn.  I have one in my shed, it's interesting how voltage varies down my way depending on the weather (guess a lot of the locals use electric heaters and more lights on in winter).

My old extension cable used to drop to 200V with the immersion on, effectively derating my 3kw immersion to just under 2.1kw.  Now I've got a buried 50A cable things happen a bit quicker

[1958steveflying]

for this calc is it circulating via a pump aswell? mine is not. also the oil i heat has been bed sheet filtered with natural settle for free water out, and i pull from 8 inches up to get goodish oil to go in my pot for cooking. also it uses the standard thermostat (which trips in / out) and isnt set to be on permanatly say via a PID etc. my insulation round the tank is thick loft insulation and heavy duty tin fiol over that aswell as on lid (holds heat 3 days). with gradual loss of course.

does have 1 bad piont though, its on an extension cable to shed. 

i would expect that sort of time of 1 hour for water heating but dont get that with oil

If you are using the stat fitted in the immersion and do not pump, it will be switching off and taking ages to come back on due to the lack of movement around the element. Perhaps consider a tank band thermostat fitted on the opposite side to the immersion heater, then it wont switch off until it is pretty much up to temperature. 

[Tony]

I heat without pumping in my inverted hot water cylinder, and have never seen the stat switch off due to lack of convection movement in the oil.  It sticks in at about 45 degrees from the bottom - maybe this has a positive influence?

[Head Womble]

I would have thought that the orientation of the heater may have an effect on how often the cycles on and off.

[1958steveflying]

I heat without pumping in my inverted hot water cylinder, and have never seen the stat switch off due to lack of convection movement in the oil.  It sticks in at about 45 degrees from the bottom - maybe this has a positive influence?

I can see yours being the best orientation for convection only.

 My mucky drum as I call it is a cone bottom 205 drum, the heater is fitted about 150mm up from the bottom rim of the drum, historically it has never had a stat, just a light rigged with the heater so I know it is on.
However. Recently the element blew when I was draining the drum with the heater on and I was not in the garage (pop) So the new element went in with the stat and I could not believe the amount of time the heater spent off rather than on, the oil was very thick but took an unrealistic amount of time to heat until I bypassed the stat again.

[Tony]

Interesting.  Thinking back, the only time I saw the stat cycle was just before it blew trying to process gloopy chinese oil.  The immersion came out caked thick in gunk.   But with my liquid feedstock no cycling at all.

Maybe I'll put the immersion a little lower on the new processor then, on the dome of the cylinder so it points up a bit.  All useful info!

[Rotary-Motion]

I heat without pumping in my inverted hot water cylinder, and have never seen the stat switch off due to lack of convection movement in the oil.  It sticks in at about 45 degrees from the bottom - maybe this has a positive influence?

I can see yours being the best orientation for convection only.

 My mucky drum as I call it is a cone bottom 205 drum, the heater is fitted about 150mm up from the bottom rim of the drum, historically it has never had a stat, just a light rigged with the heater so I know it is on.
However. Recently the element blew when I was draining the drum with the heater on and I was not in the garage (pop) So the new element went in with the stat and I could not believe the amount of time the heater spent off rather than on, the oil was very thick but took an unrealistic amount of time to heat until I bypassed the stat again.

that makes perfect sense, i chose not to remove the stat as i was worried for the extention cable, at least with tripping in and out the cable gets time to cool, i do have a thermostat of the old type variety (no safety trip out) which starts at 50c i belive the scale is upto 90c if i remeber, which would put it permantly on till clearing 50c temp in the oil, then trip in / out till 60c, which would speed things up but still worries me on the cable ext. the plug and cable gets warm when cooking for 3 hours.

but yes your right if heater was on all the time i might get speeds of 1 hour maybe?

think i will just live with it, i have for 4 years now.

but going back to the calc tool, maybe its a very general/average time and has outside factors that will alter it vastly.

[Tony]

but going back to the calc tool, maybe its a very general/average time and has outside factors that will alter it vastly.

Absolutely, it only gives best case ideal circumstances to give an idea of what to expect.  Inevitably heating will take longer but for factors that can't easily be taken into account (insulation, cycling, water present, voltage drop down cable).  Maybe we should add a few more notes to the description at the top.

Edit: Done that - please check it out and say if you think it makes sense.

At least your exercise in using the calculator has highlighted ways you could speed up heating in your system and that our calculator is "best case" which wasn't mentioned as part of the calculator.

[Rotary-Motion]

but going back to the calc tool, maybe its a very general/average time and has outside factors that will alter it vastly.

Absolutely, it only gives best case ideal circumstances to give an idea of what to expect.  Inevitably heating will take longer but for factors that can't easily be taken into account (insulation, cycling, water present, voltage drop down cable).  Maybe we should add a few more notes to the description at the top.

Edit: Done that - please check it out and say if you think it makes sense.

At least your exercise in using the calculator has highlighted ways you could speed up heating in your system and that our calculator is "best case" which wasn't mentioned as part of the calculator.

nice one will have a read...