Author Topic: Dual BrewPi True GDM-12 Fermentation Chamber Build  (Read 1205 times)

Offline xtrmnt

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Dual BrewPi True GDM-12 Fermentation Chamber Build
« on: January 14, 2014, 07:21:34 AM »
I must admit I was a little nervous about tearing into my two True GDM-12 glass door refrigerators. Though, the process of modifying them and building the BrewPi's was very rewarding and I am even more glad to have active fermentation going for a Dopplebock and Double IPA using the new BrewPi controllers. I love being able to be laying in bed and pull up the BrewPi management webpage and see what is happening or modify the fermentation profile. By By Johnson Controls, Hello BrewPi!















Of course, now you are wondering...

What is BrewPi?

BrewPi is a fermentation temperature controller for brewing beer or wine. It runs on Raspberry Pi and an Arduino. Compared to other temperature controllers, BrewPi offers much better temperature control and a lot more features like data logging, a web interface and graphs. BrewPi is open source and has an active community. BrewPi developers are working hard to support mash control (BIAB, HERMS or RIMS) in the near future.

BrewPi runs on two very popular boards: a Raspberry Pi and an Arduino. The Raspberry Pi is a credit card sized computer that runs Linux. In BrewPi it runs the web server and a python script to log data and manage settings. The Arduino is a microcontroller board that reads the temperature sensors and activates the cooler, heater and other actuators. It also has an LCD and knob to display and change settings.

Stability and flexibility

The Arduino runs the temperature control algorithm autonomously. If you don't care about data logging, it can control your beer without the Rasberry Pi. This makes this combo very stable: if the Raspberry Pi crashes, the Arduino will still keep your beer temperature perfectly under control. And being a simple embedded device, the Arduino just does not crash. If you want to run BrewPi on something else than a Raspberry Pi, you can! Any platform that has USB and can run a web server and Python will be able to run BrewPi.
Web interface

BrewPi runs a local web server that provides a great interface to change settings, view brewing data and to configure your controller. The web interface shows interactive graphs of your current brew and previous brews. You can easily start a new brew, view what the control algorithm is doing, check the logs, load/save temperature profiles, edit the active profile, etc.

Visit BrewPi.com for more information.

Offline Steve in TX

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Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
« Reply #1 on: January 14, 2014, 07:27:43 AM »
I've been lusting after a brewpi for a while. Glad to hear you love it.

Offline klickitat jim

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Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
« Reply #2 on: January 14, 2014, 07:44:52 AM »
The log function out to prove or debunk a bunch of theories. They should give a couple to one of our experiment geeks.

Offline yso191

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Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
« Reply #3 on: January 14, 2014, 10:45:47 AM »
An awesome setup.  I shopped for some time to find a commercial fridge like what you have but couldn't get within a few hundred dollars of an upright at Sears.  So I did that.  It sure would be nice to see the airlock/blow-off like you can.
Steve

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Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
« Reply #4 on: January 14, 2014, 11:12:38 AM »
Cool! What's Pepsi?
Thank you BEER!

Offline AmandaK

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Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
« Reply #5 on: January 14, 2014, 11:58:37 AM »
I've been lusting after a brewpi for a while. Glad to hear you love it.

Same here, but I can't wrap my head around it. :(
Amanda Kertz
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Offline Steve in TX

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Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
« Reply #6 on: January 14, 2014, 12:46:58 PM »

I've been lusting after a brewpi for a while. Glad to hear you love it.

Same here, but I can't wrap my head around it. :(

I hear what you mean. Look at the builds people post in his forum. Makes more since when you see how others did it. His personal build requires messing the the fridge wiring, but you can go so many ways with what he has done.

He has also streamlined the install and setup from what I can see.

I plant to use powertails instead of wiring the solid state relays. Powertails are basically power supplies with a cord and an outlet along with the inputs that the brewpi would us to tell it to turn on. Way easier that way.

Offline xtrmnt

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Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
« Reply #7 on: January 14, 2014, 01:11:44 PM »
Cool! What's Pepsi?

Pepsi is the Dopplebock and the other fridge with the "Coke" handle has the Double IPA.  :)

Offline xtrmnt

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Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
« Reply #8 on: January 14, 2014, 01:27:14 PM »

I've been lusting after a brewpi for a while. Glad to hear you love it.

Same here, but I can't wrap my head around it. :(

I hear what you mean. Look at the builds people post in his forum. Makes more since when you see how others did it. His personal build requires messing the the fridge wiring, but you can go so many ways with what he has done.

He has also streamlined the install and setup from what I can see.

I plant to use powertails instead of wiring the solid state relays. Powertails are basically power supplies with a cord and an outlet along with the inputs that the brewpi would us to tell it to turn on. Way easier that way.

Yes. There are many ways to do it. Initially both refrigerators were connected to Johnson Controls which would control heating or cooling, but not both. The BrewPi handles both heating and cooling. Also to note in comparison, the BrewPi will hold the beer temperature within a 0.1°F. This is significantly different than the Johnson Control that will hold the beer temperature within a range of 2-4°F (or whatever differential you set it to). Because the BrewPi acts like a PID, it is capable of amazing temperature control. By setting up a beer profile within the BrewPi web management page, you can easily step up for a Diacetyl rest, make a slow step down for cold crashing, or do slow temperature steps if wanting the beer to self rise but not get out of control.

Offline morticaixavier

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Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
« Reply #9 on: January 14, 2014, 01:29:09 PM »

I've been lusting after a brewpi for a while. Glad to hear you love it.

Same here, but I can't wrap my head around it. :(

I hear what you mean. Look at the builds people post in his forum. Makes more since when you see how others did it. His personal build requires messing the the fridge wiring, but you can go so many ways with what he has done.

He has also streamlined the install and setup from what I can see.

I plant to use powertails instead of wiring the solid state relays. Powertails are basically power supplies with a cord and an outlet along with the inputs that the brewpi would us to tell it to turn on. Way easier that way.

Yes. There are many ways to do it. Initially both refrigerators were connected to Johnson Controls which would control heating or cooling, but not both. The BrewPi handles both heating and cooling. Also to note in comparison, the BrewPi will hold the beer temperature within a 0.1°F. This is significantly different than the Johnson Control that will hold the beer temperature within a range of 2-4°F (or whatever differential you set it to). Because the BrewPi acts like a PID, it is capable of amazing temperature control. By setting up a beer profile within the BrewPi web management page, you can easily step up for a Diacetyl rest, make a slow step down for cold crashing, or do slow temperature steps if wanting the beer to self rise but not get out of control.

isn't the intent of the differential more to protect your compressors from the effects of rapid cycling? (sweet setup by the way)
"Creativity is the residue of wasted time" - A. Einstein

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Offline xtrmnt

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Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
« Reply #10 on: January 14, 2014, 01:40:44 PM »

I've been lusting after a brewpi for a while. Glad to hear you love it.

Same here, but I can't wrap my head around it. :(

I hear what you mean. Look at the builds people post in his forum. Makes more since when you see how others did it. His personal build requires messing the the fridge wiring, but you can go so many ways with what he has done.

He has also streamlined the install and setup from what I can see.

I plant to use powertails instead of wiring the solid state relays. Powertails are basically power supplies with a cord and an outlet along with the inputs that the brewpi would us to tell it to turn on. Way easier that way.

Yes. There are many ways to do it. Initially both refrigerators were connected to Johnson Controls which would control heating or cooling, but not both. The BrewPi handles both heating and cooling. Also to note in comparison, the BrewPi will hold the beer temperature within a 0.1°F. This is significantly different than the Johnson Control that will hold the beer temperature within a range of 2-4°F (or whatever differential you set it to). Because the BrewPi acts like a PID, it is capable of amazing temperature control. By setting up a beer profile within the BrewPi web management page, you can easily step up for a Diacetyl rest, make a slow step down for cold crashing, or do slow temperature steps if wanting the beer to self rise but not get out of control.

isn't the intent of the differential more to protect your compressors from the effects of rapid cycling? (sweet setup by the way)

You are correct regarding the differential. Within the BrewPi, the minimum cool time is set to 5 mins and the max idle time is set to 5 mins. This setting is hardcoded into the software to protect the compressor. Of course, even with a 5 on 5 off setting, the compressor cycles a lot, but due to the thermal load of the conical/beer, especially on a large batch, the idle times can be pretty long. The compressor would be cycling more often during the most active part of the fermentation. For instance, my Dopplebock is currently set to 48°F, but due to the low end of the yeast temperature, the activity is steady but not spiking all the time. In this case, the compressor doesn't come on that often.

Offline morticaixavier

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Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
« Reply #11 on: January 14, 2014, 02:04:57 PM »
[...]isn't the intent of the differential more to protect your compressors from the effects of rapid cycling? (sweet setup by the way)

You are correct regarding the differential. Within the BrewPi, the minimum cool time is set to 5 mins and the max idle time is set to 5 mins. This setting is hardcoded into the software to protect the compressor. Of course, even with a 5 on 5 off setting, the compressor cycles a lot, but due to the thermal load of the conical/beer, especially on a large batch, the idle times can be pretty long. The compressor would be cycling more often during the most active part of the fermentation. For instance, my Dopplebock is currently set to 48°F, but due to the low end of the yeast temperature, the activity is steady but not spiking all the time. In this case, the compressor doesn't come on that often.

cool.
"Creativity is the residue of wasted time" - A. Einstein

Jonathan I Fuller

Offline xtrmnt

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Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
« Reply #12 on: January 15, 2014, 05:21:06 PM »
The BrewPi developer ask me to post this on his behalf:

"Regarding the idle zones for the beer temp and cycling, in the BrewPi control algorithm there are a few things to prevent cycling and to protect the compressor:

- There are hard coded minimum OFF times (5 minutes) and minimum ON times (3 minutes) to protect the compressor. These are not user configurable, on purpose.
- For the fridge temperature, you can set the idle zone (upper and lower limit) in the web interface. The default is -1 and +1 degrees Celsius, compared to the fridge setting.
- For the fridge temperature, BrewPi estimates the overshoot that will occur and turn off the compressor in advance.

- The goal of course is to control beer temperature and not fridge temperature. So when BrewPi is set to 'beer constant' or 'beer profile' mode, it will adjust the fridge setting dynamically. To do this, it calculates the proportional, integral and derivative error in beer temp and adds these to the beer setting. The result is the fridge setting. You can adjust this calculation to match your setup. Please refer to this image: http://www.brewpi.com/wp-content/uploads/2014/01/control-algorithm.png
- By controlling the fridge temperature to adjust the beer temperature, the beer temperature fluctuates a lot less. Here is an example where the beer is generating heat, so the fridge temperature is below the beer temperature constantly: http://www.brewpi.com/#jp-carousel-1098

I am working on a different way to calculate the derivative for the beer temperature, so the fridge setting will have less spikes. The spikes are caused by the digital sensor: when the least significant bit toggles it seems to rise quickly.

Cheers!

Elco"

Offline morticaixavier

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Re: Dual BrewPi True GDM-12 Fermentation Chamber Build
« Reply #13 on: January 15, 2014, 09:31:57 PM »
The BrewPi developer ask me to post this on his behalf:

"Regarding the idle zones for the beer temp and cycling, in the BrewPi control algorithm there are a few things to prevent cycling and to protect the compressor:

- There are hard coded minimum OFF times (5 minutes) and minimum ON times (3 minutes) to protect the compressor. These are not user configurable, on purpose.
- For the fridge temperature, you can set the idle zone (upper and lower limit) in the web interface. The default is -1 and +1 degrees Celsius, compared to the fridge setting.
- For the fridge temperature, BrewPi estimates the overshoot that will occur and turn off the compressor in advance.

- The goal of course is to control beer temperature and not fridge temperature. So when BrewPi is set to 'beer constant' or 'beer profile' mode, it will adjust the fridge setting dynamically. To do this, it calculates the proportional, integral and derivative error in beer temp and adds these to the beer setting. The result is the fridge setting. You can adjust this calculation to match your setup. Please refer to this image: http://www.brewpi.com/wp-content/uploads/2014/01/control-algorithm.png
- By controlling the fridge temperature to adjust the beer temperature, the beer temperature fluctuates a lot less. Here is an example where the beer is generating heat, so the fridge temperature is below the beer temperature constantly: http://www.brewpi.com/#jp-carousel-1098

I am working on a different way to calculate the derivative for the beer temperature, so the fridge setting will have less spikes. The spikes are caused by the digital sensor: when the least significant bit toggles it seems to rise quickly.

Cheers!

Elco"

awesome! Thanks for posting.
"Creativity is the residue of wasted time" - A. Einstein

Jonathan I Fuller