My Brew System Build

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np0x
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Re: My Brew System Build

Post by np0x » Mon Apr 06, 2009 7:46 am

If you are measuring the temperature of the wort, i would set it at 1F, and use differential control. Using PID will result in cycling the fridge compressor into destruction. I hear ya about temps, FWIW, I ferment in 5 gallon batches, so my thermal masses are smaller.
Check out the Brew Buddy for iphone controlling your bcs-460.

datamike
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Re: My Brew System Build

Post by datamike » Mon Apr 06, 2009 8:38 am

I usually ferment 5 gallons too. I guess my specific question is if I want to ferment at say, 68f, when should the cooling circuit be tripped and when should the heat circuit be tripped?

I am sure it will take some trial and error testing as soon as I get the fridge hooked up.

Michael

np0x
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Re: My Brew System Build

Post by np0x » Mon Apr 06, 2009 8:50 am

Yeah, you need to make sure you don't have a dualing banjo's equivalent in fermentation temperature control. it will take some watching. The data logger will be the tool to figure this out. Just configure your fermentor a single stage control, then set a temperature, you can log the temp of the wort and see if it overshoots or not. Based on that you can decide how big of a dead zone you need to setup. The differential control will overshoot the target by 50% of it's "Differential Swing", so 68 with a 2F Diff Swing, will between 67-69.
Check out the Brew Buddy for iphone controlling your bcs-460.

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ECC
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Re: My Brew System Build

Post by ECC » Mon Apr 06, 2009 9:01 am

The trick with dual stage temperature control is to make sure that the two setpoints are close enough to get tight tolerances, but not too close that the heat/cool cycles don't step on each other. Maybe better to explain with a diagram, hopefully an ASCI text diagram won't confuse the matter :). I'll use an example of setting the with differential swings set at 2deg, with a 2 deg deadband.

Code: Select all

73 -- Cool + swing/2 (turn cool ON)
   --
72 ----Cool Setpoint
   --
71 -- Cool - swing/2 (turn cool OFF)
   -
70 -Deadband -> Desired final temperature of the system
   -
69 -- Heat + swing/2 (turn Heat OFF)
   --
68 ----Heat Setpoint
   --
67 -- Heat - swing/2 (turn Heat ON)
Both outputs should be associated with the same temperature probe, but in different Heat/Cool modes. In this example, you would set the freezer to 72, and the heater to 68. If you had an absolutely perfect (ideal) system, you could get rid of the deadband completely, and overlap the swings. But in reality, especially dealing with large thermal masses, you'll want to have some deadband and some swing programmed because the Heat or Cool may overshoot, and you don't want the Heat/Cool to constantly be playing tug of war.. If you look at any dual stage controller (like a Ranco or Love), you'll see a very similar diagram.
--Edit-- Yep, np0x beat me to it again 8-)

np0x
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Re: My Brew System Build

Post by np0x » Mon Apr 06, 2009 9:13 am

The dead band issue was why I am measuring a smaller volume of water. My thinking was that if I used a small volume of water the oscillations of temp in the fermentation chamber would be dead on my average resulting in a very static fermentation temperature as the averages of the variations would be all the liquid(larger thermal mass) would see.

All that being said, I do need to add a probe to a fermentor to confirm I am not building heat that I am unaware of in with the hotter yeasts. Back to the datalogger...
--Edit-- Yep, np0x beat me to it again
I try.
Check out the Brew Buddy for iphone controlling your bcs-460.

datamike
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Re: My Brew System Build

Post by datamike » Tue Apr 21, 2009 5:29 am

Thanks for the info and example!

I am now in the testing and calibration phase of this brewing project. The good news is that the 460 is working great and I am starting to get the hang of using it. And one other thing - my brew system is now...WIRELESS! The pic shows the wifi router/bridge bungeed onto the control box containing the 460.

I can check my fermentation temps from my recliner. :lol:

Michael

Image

missing_link
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Re: My Brew System Build

Post by missing_link » Wed Apr 22, 2009 5:40 am

Nice.

I bought a wireless access point and I can't get my computer to even recognize that I have it plugged in.

Linc

datamike
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Re: My Brew System Build

Post by datamike » Wed Apr 22, 2009 6:30 am

missing_link wrote:Nice.

I bought a wireless access point and I can't get my computer to even recognize that I have it plugged in.

Linc
Post some more info, and maybe I can help you. What brand/model? What happens when you plug it in? Are you trying to use it as a wireless access point or a wireless bridge?

Michael

missing_link
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Re: My Brew System Build

Post by missing_link » Wed Apr 22, 2009 10:42 am

Mike,

I'll take you up on that offer but it might be faster easier to do it over the phone one night

Linc

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