New Giveaway - Wort Monster Conical Fermenter!

Home Brew Forums > Home Brewing Beer > Beginners Beer Brewing Forum > How can you keep Chest freezer on or off longer?




Reply
 
LinkBack Thread Tools Display Modes
Old 07-11-2012, 02:42 AM   #21
BetterSense
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jul 2011
Location: Richardson, Texas
Posts: 977
Liked 45 Times on 35 Posts
Likes Given: 3

Default

PI normally stands for Proportional and Integral, not Program and Interval.

I have a homemade temp controller and I have the 'dead band' set so that the freezer is off for 30-45 minutes before kicking on for about 10 minutes. This results in about 12 degrees F of temp swing, measured by air temp. If the OP can adjust his temp controller's dead band, I would do that just because it's easier, if not, the jar of water trick or strapping it to a keg works as well.



__________________
BetterSense is offline
 
Reply With Quote Quick reply to this message
Old 07-11-2012, 02:42 AM   #22
Revvy
Post Hoc Ergo Propter Hoc
HBT_LIFETIMESUPPORTER.png
Feedback Score: 0 reviews
 
Revvy's Avatar
Recipes 
 
Join Date: Dec 2007
Location: "Detroitish" Michigan
Posts: 40,794
Liked 2661 Times on 1606 Posts
Likes Given: 3452

Default

OK Tylo I don't know if this will help, or if the way to set things on a love are the same as it is for my Ebay STC-1000 but I'm at 1 hour and 22 minutes since the last time my compressor kicked off (it ran for 10 minutes) and it JUST kicked on, and the temp has only risen .5 degrees C (that's what 3 degrees f?) in that time, but the settings on my controller are;

Temp Set Value, 4.6 degrees C.
Difference Set Value, 0.5 degrees.
Compressor Delay Time 10 minutes (maximum for the stc-1000 iirc)
Temp Calibration Value 0.0



__________________

Like my snazzy new avatar? Get Sons of Zymurgy swag, here, and brew with the best.

Revvy's one of the cool reverends. He has a Harley and a t-shirt that says on the back "If you can read this, the bitch was Raptured. - Madman

I gotta tell ya, just between us girls, that Revvy is HOT. Very tall, gorgeous grey hair and a terrific smile. He's very good looking in person, with a charismatic personality... he drives like a ****ing maniac! - YooperBrew

Revvy is offline
 
Reply With Quote Quick reply to this message
Old 07-11-2012, 03:56 AM   #23
tylo_k2008
Feedback Score: 0 reviews
Recipes 
 
Join Date: May 2012
Location: Phoenix, AZ
Posts: 82
Liked 1 Times on 1 Posts
Likes Given: 1

Default

Ya. Thanks thats what I couldn't figure out. I had another thread asking how to set the perimeters on it, but lacked the response. The only thing I really figured out is how to set the set point to and like I said it has been staying between 35 and 38 degrees, which is what I wanted. The thing I hadn't figured out was how to make the cycles longer. I live in an apartment, so building this thing has taken a little longer then it normally would. The probe wrapped in bubblewrap hasn't helped as much as I needed it to. I think I am gonna go ahead and try it submersed in water. I think the pill bottle idea is pretty awesome! Also I just have the collar sitting on top of the chest freezer. I insulated the inside and taped it off, but fear of my chest freezer not working out, I have been trying not to screw, seal, or bolt anything into it. I believe I am already so deep in this project that I might as well start. I should probably seal it off a little better assuming that the probe being submersed still doesn't give me the results I am looking for.

__________________
tylo_k2008 is offline
 
Reply With Quote Quick reply to this message
Old 07-11-2012, 03:59 AM   #24
TimpanogosSlim
Feedback Score: 1 reviews
Recipes 
 
Join Date: Mar 2012
Location: Orem, UT
Posts: 958
Liked 76 Times on 67 Posts
Likes Given: 5

Default

Quote:
Originally Posted by BetterSense View Post
PI normally stands for Proportional and Integral, not Program and Interval.

I have a homemade temp controller and I have the 'dead band' set so that the freezer is off for 30-45 minutes before kicking on for about 10 minutes. This results in about 12 degrees F of temp swing, measured by air temp. If the OP can adjust his temp controller's dead band, I would do that just because it's easier, if not, the jar of water trick or strapping it to a keg works as well.
indeed, I remembered that wrong.

It's just that i start to twitch when i read some of the bizarre lore about temperature control here and some other places. Immersing the thermocouple isn't a terrible thing, but, why not at least try to use the technology you already bought?

What really gets me is when people decide that regular PID doesn't work and instead hook up the alarm outputs to relays, so that they can accomplish with hardware what they could accomplish with the built-in software if they read the manual. and had someone around to explain the theory. I admit to having a good friend with a background in factory automation.

Decades ago, whole teams of people worked out how to do this, back when cpu cycles were really expensive. They even came up with ways to do it without software. More recently, some coder put in hours implementing the equations someone else derived. Hopefully, someone like me put in hours making sure his implementation works the way it ought. Seems a shame to ignore all that just because telling the controller to ignore temperature fluctuation until you are +3 over set point results in a less appealing user experience than mechanically buffering the input.
__________________
TimpanogosSlim is offline
 
Reply With Quote Quick reply to this message
Old 07-11-2012, 01:04 PM   #25
Revvy
Post Hoc Ergo Propter Hoc
HBT_LIFETIMESUPPORTER.png
Feedback Score: 0 reviews
 
Revvy's Avatar
Recipes 
 
Join Date: Dec 2007
Location: "Detroitish" Michigan
Posts: 40,794
Liked 2661 Times on 1606 Posts
Likes Given: 3452

Default

Quote:
Originally Posted by tylo_k2008 View Post
Ya. Thanks thats what I couldn't figure out. I had another thread asking how to set the perimeters on it, but lacked the response. The only thing I really figured out is how to set the set point to and like I said it has been staying between 35 and 38 degrees, which is what I wanted. The thing I hadn't figured out was how to make the cycles longer. I live in an apartment, so building this thing has taken a little longer then it normally would. The probe wrapped in bubblewrap hasn't helped as much as I needed it to. I think I am gonna go ahead and try it submersed in water. I think the pill bottle idea is pretty awesome! Also I just have the collar sitting on top of the chest freezer. I insulated the inside and taped it off, but fear of my chest freezer not working out, I have been trying not to screw, seal, or bolt anything into it. I believe I am already so deep in this project that I might as well start. I should probably seal it off a little better assuming that the probe being submersed still doesn't give me the results I am looking for.

I can relate to building it in a small apartment.

The biggest thing to help is to make as tight a seal between collar and freezer as possible. The thing about 100% silicone caulk that many of us use is that you can peel off the collar and caulk if you need to. Some folks use liquid nails but silicone is not permanent if you need it gone and won't harm the fridge.
__________________

Like my snazzy new avatar? Get Sons of Zymurgy swag, here, and brew with the best.

Revvy's one of the cool reverends. He has a Harley and a t-shirt that says on the back "If you can read this, the bitch was Raptured. - Madman

I gotta tell ya, just between us girls, that Revvy is HOT. Very tall, gorgeous grey hair and a terrific smile. He's very good looking in person, with a charismatic personality... he drives like a ****ing maniac! - YooperBrew

Revvy is offline
 
Reply With Quote Quick reply to this message
Old 07-11-2012, 03:27 PM   #26
UTPhish
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
UTPhish's Avatar
Recipes 
 
Join Date: Jan 2012
Location: Salt Lake City, UT
Posts: 162
Liked 11 Times on 10 Posts
Likes Given: 10

Default

Quote:
Originally Posted by tylo_k2008 View Post
I think I am gonna go ahead and try it submersed in water. I think the pill bottle idea is pretty awesome!
Submerging the temperature probe has worked well for me. I originally had my temperature probe submerged in a small water bottle inside my keezer. My compressor would kick on for 15 minutes every 1 - 1.5 hours. The temperature would fluctuate between 39.5°F and 41°F during this time. I have modified my probe setup in order to increase the cycle time. My probe is now inside a 6 inch thermowell that sits in a large Aquafina bottle. The bottle sits at the bottom of the keezer next to my CO2 tank. The compressor kicks on for 20 - 25 minutes every 3.5 - 4 hours. The temperature fluctuates between 39°F and 41°F during the cycle.
__________________
Primary: Flanders Red #3, House Pale Ale, House IPA, Zombie Dust Clone
Kegged: Blonde Ale, Stone Enjoy By Clone, Berliner Weisse
Aging Saison w/ Brett B, Flanders Red #1, Flanders Red #2
UTPhish is offline
Revvy Likes This 
Reply With Quote Quick reply to this message
Old 08-01-2012, 07:15 AM   #27
cwi
Registered User
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jun 2010
Location: Austin
Posts: 845
Liked 30 Times on 27 Posts
Likes Given: 1

Default

Quote:
Originally Posted by tylo_k2008 View Post
The probe wrapped in bubblewrap hasn't helped as much as I needed it to.
You are either misreading the original suggestion, or miswriting your application of it.

Tape, or, even easier, strap, the probe to something massive- like a keg -, THEN insulate over the top of it. Attaching the insulation with more bungy/elastic cord is what I have found to be easiest. You should be able to reduce the temp diff to ~1F and still cycle less than 1/hour. If not, insulate the probe even more (but not between it and the keg).

Your description reads like you insulate the probe, then attach it to the keg, which will not give the desired effect of reducing cycling (or controlling the temp of the beer accurately).

The collar insulation needs to be glued or fit very tightly to the collar. That makes a big difference in cycling freq as well, since wood is a poor insulator. Adding a fan will become more important as your cycle freq decreases, since the air will stratify even more during the longer off times.
__________________
cwi is offline
 
Reply With Quote Quick reply to this message
Old 08-01-2012, 07:33 AM   #28
cwi
Registered User
Feedback Score: 0 reviews
Recipes 
 
Join Date: Jun 2010
Location: Austin
Posts: 845
Liked 30 Times on 27 Posts
Likes Given: 1

Default

Quote:
Originally Posted by TimpanogosSlim View Post
Decades ago, whole teams of people worked out how to do this, back when cpu cycles were really expensive. They even came up with ways to do it without software. More recently, some coder put in hours implementing the equations someone else derived. Hopefully, someone like me put in hours making sure his implementation works the way it ought. Seems a shame to ignore all that just because telling the controller to ignore temperature fluctuation until you are +3 over set point results in a less appealing user experience than mechanically buffering the input.
Quote:
Originally Posted by TimpanogosSlim View Post
I admit to having a good friend with a background in factory automation.
Is that like not really being a doctor, but playing one on TV?

You don't know what you are talking about. The suggestions you made about blindly increasing 'on times' and 'off times' is a guaranteed way to increase temp variance. Those control parameters are mainly used for commercial systems where they have to put the sensor on a fixed mass in a fixed location, but have varying cooling loads. It is a 'best fit' type work around, which is a complete kluge compared to the completely modern and correct approach of placing the sensor on the primary indicator- the beer. The 'minimum off' time should be used as ASD, and set for at least 10 minutes. While increased cycling freq may take a few years off the life of a freezer, not having adequate ASD can kill your compressor in a few hours, and has.

The most commonly suggested, and correct, method for a keezer is to attach the sensor to the smallest container (or to a reasonable facsimile) in the keezer, then insulate over it. The temp diff can then be used to adjust cycling freq to anything desired, at the cost of temp variance or compressor life of course. The reason to attach the sensor to a smallish container is to prevent freezing and collateral damage that may result if the sensor is on something much more massive than the smallest container, and set close to freezing.

As for those that hang their sensor in air and guess at the temp setting and differential, I would have to be even more blunt than I already have been.
__________________
cwi is offline
 
Reply With Quote Quick reply to this message
Old 08-01-2012, 08:09 AM   #29
Dan
HBT_SUPPORTER.png
Feedback Score: 0 reviews
 
Dan's Avatar
Recipes 
 
Join Date: Oct 2010
Location: Hanford, CA
Posts: 5,677
Liked 1686 Times on 1050 Posts
Likes Given: 2454

Default

Edit: Guess I posted a bit to quickly without reading the whole thread. Didn't realize temp control could be such a heated topic!

MY original post was a question to Revvy (sorry OP to go OT for a quick moment).

Hey Revvy great post. I know you were working on the kegerator awhile back and saw the post with the nice keg handles but must have missed the post of your final kegerator. Can you PM me the link?

Thanks!

Dan

__________________
Dan is offline
 
Reply With Quote Quick reply to this message
Old 08-15-2012, 12:22 AM   #30
zachattack
Feedback Score: 0 reviews
Recipes 
 
Join Date: Mar 2012
Location: , MA
Posts: 2,353
Liked 212 Times on 183 Posts
Likes Given: 101

Default

Quote:
Originally Posted by TimpanogosSlim View Post
I think it's not accuracy so much as normalization.

The data that you get from a thermal sensor in free air is as accurate as ever, but what it's telling you is not necessarily what you want to know. Unlike a liquid caught in a thin channel or a needle attached to a bimetallic spring, it reacts immediately to the changes around it.

Laboratory types call a thermometer "traceable" when, among other things, it averages the temperature it reads over a pre-determined duration of time, so that when they open the door of a refrigerator the number on the display gives them a useful impression of the temperature it has been reading instead of a reaction to the door being opened.

By adjusting the software parameters of a PI (Program and Interval) controller - in this case the c0 and c1 parameters to do what the OP asked, and r0 to make it less interested in minor deviations in temperature - we can make it behave in much the same way as it behaves when you swamp the sensor with a big thermal buffer. Bolting it to a large piece of metal would have a similar effect, fwiw, if you had good enough thermal contact.

But it won't make the display on the willhi controller change it's digits slower.

I referenced being a QA manager not because it means that i am smart - i am clearly a dumbass for getting talked into this management gig - but because it means that i have been conditioned to complain about things that don't seem right to me.
I stumbled upon this thread and don't mean to resurrect something just to complain, but I need to clear up a few things.

PID does indeed stand for Proportional Integral Derivative control. It's a control method that allows you to fine-tune control by adjusting the three PID parameters to account for the rate of change of your process variable as well as the historical error in the control loop. It's fantastic if you need to control a heating element, a proportional valve to control pressure or flow rate, but it can only be used on something with variable (or simulated variable) output. The parameters that you mention are in no way related to PID, the only parameters are P, I and D. But none of that matters, since a refrigerator can only be on or off PID is completely irrelevant here. We're using on/off control, not PID control.

Also, the word traceable means traceable, nothing more. A traceable thermometer is one with a traceable calibration, it says nothing about how/if it averages data.

If you're going to rant, criticize and complain, at least have some clue what you're talking about.


__________________
zachattack is offline
cwi Likes This 
Reply With Quote Quick reply to this message
Reply


Quick Reply
Message:
Options
Thread Tools
Display Modes


Similar Threads
Thread Thread Starter Forum Replies Last Post
Chest Freezer or No-Freezer Fridge? Kesigage Beginners Beer Brewing Forum 9 01-18-2013 07:16 PM
Best use for a chest freezer Waynep005 Beginners Beer Brewing Forum 11 11-08-2011 12:35 AM
chest freezer Aschecte Beginners Beer Brewing Forum 2 07-21-2011 07:12 PM
chest freezer Marathon06 Beginners Beer Brewing Forum 9 07-12-2011 05:13 PM
Got a big chest freezer for $25..need some help! Beernewb Beginners Beer Brewing Forum 12 07-11-2010 12:22 PM