it sounds like 2400watt is the largest a single 10A household circuit can take - how do braumeister do theirs with two elements?
its hard to tell from people's build photos - are heating elements ok with touching each other (as they go around the pot) or are they bent / kept separate in some other way? if so - how?
has anyone used a little brown pump for a large system / high gravity? worth trying or just skip to something larger?
it seems like there have been differing reports on how effective a 2400w element has been for different people.
Yes. Long answer is Watts / Volts = Amps. 2400w / 240v = 10a. Yes 2400 watts is the maximum for a 10 amp circuit (there are other factors but lets just stay simple).
15 amp circuits are the next commonly installed in houses and sheds (eg a lot of kitchen stoves have a 15amp circuit). 3600 / 240 = 15. Thus on a 15amp circuit you could run 3600 watt appliances. You can get a sparky in to install a 15 amp circuit if you want one. Some folks bypass this by running multiple 2400watt elements powered from DIFFERENT circuits in their kettles (they use extension cords). Extension cords all over the place is potetnially a hazard and a PITA. 50L Braumeister needs a 15 amp circuit. 20L BM only requires a 10amp circuit. More detail in answer to 'angus_grant'.
Braumeisters touch themselves (snigger).
Yes they have, results vary. They seem to fail more than other pumps in this setup.
2400w elements have variable results because different people try to boil different volumes in different types of pots under different conditions. The other factor is how long it takes to boil/heat.
Example with 2400 watts, 30L of water would take 42 minutes to come up to mash in temp of 68oC from 22oC. With 3600 watts, 30L of water would take 28 minutes to come up to 68oC from 22oC.
Like wise, 60L of water with 2400w would take 68 minutes (from 22oC to 68oC) and 3600w would take 56 minutes.
So 2400w of 30L has a ramp rate of 1.09oC/minute, 3600w of 30L = 1.64oC/minute.
Also 2400w of 60L = 0.67oC/minute and 3600w of 60L = 0.82oC/minute.
For ***** and giggles let's say we have two 2400w elements on different supply circuits in the kettle to heat 60L of water from 22oC to 68oC, this would take 48 minutes or 0.95oC/minute ramp rate. (These values from "Boil Time Calculator":
http://www.phpdoc.info/brew/boilcalc.html and include 95% efficiency but with an uninsulated pot in a breeze it could be significantly lower and thus take much longer)
This is for water. Wort has a different density and heating energy requirements. FWIW a 50L Braumeister which runs TWO elements to a combined total of 3200 watts, in most situations has a heating ramp time of about 1oC/minute. Just from a time value, it looks to me like 2400w is ok for 30L (single batch unit) but you'd need 3600w or so for 60L (double batch unit).
It is not just about the amount of watts but is also about the wattage density of the element. The Braumeister and many of the clones use low wattage density elements. A short element at 2400watts could more readily scortch wort than say a 2400w element 1.2m long that is bent to coil around inside of the pot. 2400w in 20cm versus 2400w in 1.2m.
And once again, they made no mention of the element touching itself (snigger snigger).
I am fairly sure the BM 50L system (with the 2 elements) is a 15A system. I am fairly sure the BM 20L system only has one element and is 10A. Or it could be that the 50L has one single higher powered heating element?
As i said above, mine touches itself (snigger).
Yes 50L BM has a center element under the malt pipe and an outer element around the outside of the malt pipe. The 50L is meant to be run on a 15amp circuit (3200w combined total watts of elements + pump + controller). A 20L BM only has one element around the outside of the malt pipe; it has an element of 2000 watts.
On my Clone I used a 50L pot and cut a 150mm diameter hole in the lid. With a 2400w element and 30L of wort this gives a very good even rolling boil. If I remove the lid I get a similar boil to what angus has explained.
The hole in the lid still lets out quite an amount of steam. I did an Oatmeal Stout today and lost approx 5L to the 75 min boil.
The lid would increase the efficiency as there is not so much loss of energy outside of the pot. This chap (
http://physics.ucsd.edu/do-the-math/2012/0...for-efficiency/) found he got 16% efficieny with a pot of water on the stove with no lid but the same pot with a complete lid and a SMALLER burner he got 27% efficiency.
You would seem to have 16% total evaporation with 3.99L/hr loss to evaporation. Factor in cooling loss, loss to trub etc and I think your losses are quite high, possibly too high. This would suggest to me that perhaps you are boiling too vigorously, i.e you are evaporating too much wort. 10-12% loss to evap seems to be about the norm. I get 10-12% evap with a rolling boil that appears to be just the wort turning over.
malted said:
Hopefully this is thought food for y'all. My head hurts, maths numbers and I don't generally get along. :icon_vomit: