Happy HolidaySs Giveaway - Last Sponsor Giveaway of the Year!

Come Enter the BrewDeals/FastFerment Giveaway!


Home Brew Forums > Home Brewing Beer > Electric Brewing > power! a practical question
Reply
 
LinkBack Thread Tools
Old 08-08-2012, 09:06 PM   #1
warthog
Feedback Score: 0 reviews
Recipes 
 
Join Date: Sep 2006
Location: Park City, Utah
Posts: 63
Liked 1 Times on 1 Posts
Likes Given: 2

Default power! a practical question

i am planning my own electric brewery. my question refers to power. the place i plan on brewing already has a 30A circuit installed, i plan on using that. i really don't want to go higher, the house is old, it has 150A service, and i find all sorts of scary wiring errors whenever i dig into something.

i am planning a 5 gallon system, but really only because of the 30A number, and i honestly would rather go 10 gallon.

so here's the question for all of yous guys who have built an electric brewery:

how long does it take to boil? my calcs tell me with 6000W max (25A at 240V) it will take 11:15 (about 1 min longer for a 5500W element) to bring my 6 gallons of wort to boil ( dT 80F - i live at 7000' boiling is ~200F and my wort comes out of my m/l tun at ~120-130).

that said, 100% of my power does not go to heating the wort, or does it? what sort of heating efficiency should i expect?

i plan on insulating my hlt, m/lt and kettle, but the tops will be open, so i expect some heavy losses there. any thought?

i guess the next question has to do with the specific heat of wort, but i think i need to assume that its greater than 1.00, i assume it depends somewhat on the o.g. but does anyone know of a formula or rule of thumb?

__________________

more beer for me

warthog is offline
 
Reply With Quote Quick reply to this message
Old 08-08-2012, 09:53 PM   #2
DustBow
Feedback Score: 0 reviews
Recipes 
 
Join Date: May 2010
Location: Cincy, OH
Posts: 657
Liked 21 Times on 19 Posts
Likes Given: 3

Default

I don't have exact numbers for you, but using a 5500w element for 5 gallon batches will be pretty painless, your temps will rise quickly. People easily brew 10 gallon batches with 5500w elements

__________________
"Brewers make wort, yeast make beer."

"Brewing beer is neither complicated nor expensive. It's the responsibility of the brewer to make it as complicated and expensive as their spouse & budget will allow."
DustBow is offline
 
Reply With Quote Quick reply to this message
Old 08-08-2012, 10:15 PM   #3
passedpawn
Waste Allocation Load Lifter - Earth Class
HBT_MODERATOR.png
Feedback Score: 0 reviews
 
passedpawn's Avatar
Recipes 
 
Join Date: Apr 2009
Location: ☼ Clearwater, FL ☼
Posts: 19,672
Liked 3624 Times on 2233 Posts
Likes Given: 3129

Default

Effectively 100% of the energy will go into the wort. A bit is lost on in the wiring and SSR, but probably only a percent or two. Of course, you will lose some to ambient depending on insulation.

Here's a plot of a 10g boil with a 5500W element. It took about 45 minutes to go from 70F to boil. Should scale linearly to batch size, so maybe 22 minutes for a 5g batch.

__________________
All the clouds are cumuloft
Walking in space
passedpawn is offline
 
Reply With Quote Quick reply to this message
Old 08-08-2012, 10:29 PM   #4
warthog
Feedback Score: 0 reviews
Recipes 
 
Join Date: Sep 2006
Location: Park City, Utah
Posts: 63
Liked 1 Times on 1 Posts
Likes Given: 2

Default

thanks! quick number crunching tells me your system is ~85% efficient at transferring electrical power into hot wort. that's actually pretty encouraging, i may scale up. how much insulation does your system use? what was the ambient temperature? i see you are in fla.

__________________

more beer for me

warthog is offline
 
Reply With Quote Quick reply to this message
Old 08-08-2012, 10:36 PM   #5
passedpawn
Waste Allocation Load Lifter - Earth Class
HBT_MODERATOR.png
Feedback Score: 0 reviews
 
passedpawn's Avatar
Recipes 
 
Join Date: Apr 2009
Location: ☼ Clearwater, FL ☼
Posts: 19,672
Liked 3624 Times on 2233 Posts
Likes Given: 3129

Default

It was winter when I did that... probably around 65F. That was on my HLT, which has NO insulation. With an electric system, there's no reason not to insulate, but really it would save me only a few minutes and maybe 5 cents, so I don't bother. I even have a whole roll of Reflectix that I did use for my keggle mash tun.

In theory, you should see the result of heat loss as a non-linearity in that line (heat loss to ambient should increase as the temp between the water and the air increaases). It's pretty linear though (hold the straight edge of a piece of paper against the curve). Also, I should look at the voltage going into my element. It's a long run from my breaker box to where I brew (~50') so there might be significant loss in the wire.

__________________
All the clouds are cumuloft
Walking in space
passedpawn is offline
 
Reply With Quote Quick reply to this message
Old 08-08-2012, 10:53 PM   #6
warthog
Feedback Score: 0 reviews
Recipes 
 
Join Date: Sep 2006
Location: Park City, Utah
Posts: 63
Liked 1 Times on 1 Posts
Likes Given: 2

Default

cool! thanks again. i'm an engineer (not an ee), so i love numbers , please check that voltage, i can work that into my calcs. my basement is about 65f year round. so those numbers should jive pretty well.

__________________

more beer for me

warthog is offline
 
Reply With Quote Quick reply to this message
Old 08-08-2012, 11:00 PM   #7
passedpawn
Waste Allocation Load Lifter - Earth Class
HBT_MODERATOR.png
Feedback Score: 0 reviews
 
passedpawn's Avatar
Recipes 
 
Join Date: Apr 2009
Location: ☼ Clearwater, FL ☼
Posts: 19,672
Liked 3624 Times on 2233 Posts
Likes Given: 3129

Default

The two numbers you really need are voltage and the element resistance. Power (watts) will be V^2 / R. I'll try to measure both of those Friday and post here. (can't measure current because everything I have is fused at 10A - I need a clampon ammeter).

__________________
All the clouds are cumuloft
Walking in space
passedpawn is offline
 
Reply With Quote Quick reply to this message
Old 08-08-2012, 11:12 PM   #8
warthog
Feedback Score: 0 reviews
Recipes 
 
Join Date: Sep 2006
Location: Park City, Utah
Posts: 63
Liked 1 Times on 1 Posts
Likes Given: 2

Default

i'm assuming i can get figure out the element resistance from its nominal wattage. v^2/w=r so at 240v^2/5500=10.47 ohm or am i missing something here?

__________________

more beer for me

warthog is offline
 
Reply With Quote Quick reply to this message
Old 08-08-2012, 11:55 PM   #9
passedpawn
Waste Allocation Load Lifter - Earth Class
HBT_MODERATOR.png
Feedback Score: 0 reviews
 
passedpawn's Avatar
Recipes 
 
Join Date: Apr 2009
Location: ☼ Clearwater, FL ☼
Posts: 19,672
Liked 3624 Times on 2233 Posts
Likes Given: 3129

Default

Quote:
Originally Posted by warthog View Post
i'm assuming i can get figure out the element resistance from its nominal wattage. v^2/w=r so at 240v^2/5500=10.47 ohm or am i missing something here?
Reality.

That's the school answer. The school answer also says that it will take 37 minutes 52 seconds to get to boil from 70F with a 5500W element. It took longer. Time to check assumptions.

Because I can't measure the element resistance with much accuracy, I'll put a regulated voltage source across it and measure the current (I can do both at the same time with my benchtop power supply )
__________________
All the clouds are cumuloft
Walking in space
passedpawn is offline
 
Reply With Quote Quick reply to this message
Old 08-09-2012, 12:50 AM   #10
passedpawn
Waste Allocation Load Lifter - Earth Class
HBT_MODERATOR.png
Feedback Score: 0 reviews
 
passedpawn's Avatar
Recipes 
 
Join Date: Apr 2009
Location: ☼ Clearwater, FL ☼
Posts: 19,672
Liked 3624 Times on 2233 Posts
Likes Given: 3129

Default

Quote:
Originally Posted by warthog View Post
i'm assuming i can get figure out the element resistance from its nominal wattage. v^2/w=r so at 240v^2/5500=10.47 ohm or am i missing something here?
OK, you were right. 10.00V applied, 0.958 amps measured, = 10.4 ohms.
__________________
All the clouds are cumuloft
Walking in space
passedpawn is offline
 
Reply With Quote Quick reply to this message
Reply



Quick Reply
Message:
Options
Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Power Lead question Airplanedoc Electric Brewing 0 02-18-2012 12:50 AM
Quick Power Cord Question Thundercougarfalconbird Electric Brewing 14 02-08-2012 07:42 PM
Power Cord Question McCuckerson Electric Brewing 7 08-20-2011 10:54 PM
120V power demand design question G-Lover Electric Brewing 11 03-01-2011 09:32 PM
power switch question doulovebeef Electric Brewing 6 01-06-2011 02:32 AM



Newest Threads

LATEST SPONSOR DEALS