Cheap Fermentation Chamber

So, I recently had won a bet with SWMBO, and my prize purse was $60 in my own slush fund.

I have decided that I want to build a fermentation chamber, and this will be my build thread. I have been looking at a lot of other ones, and as an engineer I like to tinker, and abuse things (using them for things other than they were originally intended).

I have looked at the "son of a fermentation chamber" as well as some other options and I wasn't exactly pleased with them, so hence me making my own.

My overall goal with this project is to find a solution that works, given some restraints:

• It has to be under $80 total, ($20 is from what I had left before the bet).
• It has to fit in a corner of my bar room, as I live in a row house, and that is my only sanctuary.
• I'd like it to hold 2 6.5 gallon carboys.
• I would prefer to use a mini fridge or it's guts because our freezer is kind of full and can't handle liter bottles in it.
• I would preferably like to have it raised off the ground a little bit as to make it easier for racking purposes.
• I would like to have a view window, so that I can look at it, if not a door will suffice so that I can peek in.

SWMBO has yet to come home yet, but I have just scored a Mini fridge on Craig's list for $2. The reason it was so cheep?

The person had the fridge locked for transportation, however when he went to open it, the key broke off in the lock and he couldn't get it open.

So I finally got it open, and this is what it looked like inside.


Now I am debating whether to leave the fridge as is, take off the door and use it for the chamber, or to put the door on and some how suck out the cold air. All the heat exchange coils are on the back:

This is my preliminary design/idea. And no its not pretty because I didn't want to spend the time doing it up in sketchup.

So, I bought some 2" EPS, and SWMBO found an old wire frame shelving unit at a yard sale for $5. My plan is to line the shelving unit (2'6" tall) with the EPS. I have started to dismantle the mini fridge and the pictures are below:

Decided to work on top of the Keezer, because I'm tall and it makes it easier.


Not to mention magnets help with the holding of the screws


Finally got the protection fin off.


Found the power converter


Got most of the screws and now its mainly detached from the back

What was left connected after the main part detached


Got a nice Ranco temperature controller. I probably would have paid $2 alone for just that, but i got a compressor to... BONUS



Trying to figure out what the white and black cables do, they are glued in there pretty good, Ill be trying to dig them out.


If anyone has any idea what they do, I'd much appreciate the information, and why they are going into the fridge.


EDIT: Found out what the cables go to.... A lightbulb! Ill just unscrew it at the connector, I'll have to get a multi-meter to find out what the Voltage is on that, maybe I can use it to power a fan.



Here is the plate on the inside... yes its clipped a bit but all the good information is there


As I have been dismantling this fridge, I have been very very impressed with the engineering behind it. I really like how the heat sync/heat distributor, runs into a tray that gets drained to outside the fridge, and I think I may try to incorporate something like that into the build. Also, all the parts I have seen so far are wicked solid. I have not been gentle with anything and I have yet to have something bend or break on me. Additionally, they made it really nice and easy for the wiring, and now I can go return the 3 pronged extension cord I bought to use in this.

So today I was able to cut out the particle board to fit the compressor,
The hole towards the top is for putting the cooling coil into the chamber.




This is with the compressor attached to the back

Looking good. Keep posting pics.

So I just put the guard on, and remembered I forgot to take a pic of the back of it, with all the components. I then realized that not everyone is tech/mechanically savvy, so I thought I would break it down and describe what I took off the fridge that is going to help me. If I make a mistake in describing the components please correct me.

Components:
Compressor: This takes the cold refrigerant and condenses it which causes it to get super cold.
Heat Sink: This allows for heat to be exchanged with the air more efficiently.
Transformer: This converts the power from the wall outlet into something that wont burn the fridge motors
Temp Controller: Cycles the compressor on and off
Pump and Heat exchange: This is where the heat that is absorbed inside the fridge is exchanged with the air outside of the fridge



This is the wiring view. Things to note:
Black Cable: Power Line/Load
White Cable: Neutral
Green: Ground
I added the little black mount to the wire, that is going to the wall, so that it wouldn't get yanked off.

So I finally got some time to start building again. I took out all the middle shelves, and then put the 6.5 and the 5 gal carboys in to make sure they fit, and they do. I am using the wire frame as a support inside, I'll try to not alter it to much in case we need to use it in the future.


It was hot out today, so I waited till the afternoon to do the cutting outside. I just got a large T for 13$ at Home depot, but that won't count against my budget because I expensed it against a small cubby SWMBO wanted me to build.


So cutting the Foam, made me feel like I was trapped inside of a snow globe. I'm pretty sure its in my lungs, but I used a circular saw (60 tooth finishing blade) to cut the EPS, and the cuts came out nice and clean, in the store we used a utility knife. But the saw was way better


With the stand I had, I used a 1/2 inch drill bit to cut a pilot hole where the legs of the stand were. I then pushed them through, so that they are tight and dont need to be insulated, but I will probably wrap some tape around them.



I used a mixture of Liquid Nails and toothpicks to hold the pieces in place.

Got the 5 sides put together, I am going to let the front be the removable part and just attach it with tape when I need to.


I lined all the joints with tape.


Now I am just trying to figure out how I am going to attach the compressor and coils. Once I do that, all I need is the Ebay aquarium temperature controller to come from china and I will have a complete fermentation chamber.

I started growing the yeast for the Oktoberfest I will be be brewing next weekend hopefully the controller comes in this week some time.

So I finally figured out how to mount it. I used some zip ties on the coil that pops through, to align it inside. Then I used some bolts with washers to Mount them to the organizer on the inside, because the foam wouldn't hold it. Make sure you have someone watching the drill come out the other side, so that you don't accidentally drill a hole in the coils or compressor.

I circled the mount points in red in the pictures





I then got a $6 one speed fan from Walmart, to distribute the cold air and make sure the air does not become stratified, (I've had it happen in my keezer and I put one of these fans in there too.)




Now its time to put the front on and fire up the compressor, and see how this bad Larry performs.

Just for ease of use I have attached the board pattern and cutout I used:



Cost breakdown so far:
$25 - 2" x 4' x 8' - EPS foam board
$6 - Plywood board
$6 - Walmart Fan
$2 - Mini fridge
$5 - Metal wire frame organizer
$21 - Ebay Temp controller
$8 - Project enclosure from Radio Shack
$3 - outlet plug

So the total is currently at $76.
Right on budget.

Houston we have a problem. I plugged in the compressor and set it to the highest setting. When I plug it in I hear a click, however the compressor has not yet cycled on for 30 min. I double checked the wiring and it all seems solid. Maybe this type of mini fridge takes longer to cycle on? Ugh, I would hate to have to go find a new fridge to cannibalize.

Hi

Sorry to say, but no there aren't any fridges that power off for a half hour after they are plugged in.

1) It's broke
2) It's wired wrong
3) The controller is set to max hot not max cold

Pick one. I'd go for 2 since checking the wiring is free....(I assume you twisted the dial and it's not 3).

Bob

I had left it plugged in, so I went to unplug it, before I checked the wiring, and I noticed the coils felt hot, and so did the insulation around the compressor. I felt the heat sink inside and it was cooling. It runs almost silently though, and it took a little time to ramp up to cool. The walmart fan that I put inside makes like 10x more noise than the compressor. I'll just let it run overnight to see how cool it gets. I have a digital thermometer in there, that lets me check it from outside.

I'm hoping that it cools down enough inside, otherwise I will have to cannibalize the other mini fridge I have.

My old Montgomery Ward minifrig I use for a fermentation chamber will not come on for about 30 minutes after plugging it in.

Great project, wfowlks. Thanks for all the pics. I hope you have good results on the overnight temp test.

I think you said the wire frame shelving stood 2.5 feet tall. Could you post the rest of the demensions (with foam and compressor gear on back)? How small a space will it fit in to?

That looks like an absorption fridge - Like in an RV. The refrigerant is actually ammonia based. If it is it should be quiet as if I remember, the "compressor" is actually a heat coil that heats the ammonia. I've never soon a portable one before. That's kinda cool...

http://rvrefrigeratorrepair.com/how_it_cools.html

wfowlks said:

This is the wiring view. Things to note:
Black Cable: Negative
White Cable: Live / Power line
Green: Ground

View attachment 65801

Click to expand...

Nice Build Hope all is well and working.

BUT, if this is standard american wiring

Black = Live
white = Negative / Neutral
Green = Ground / Earth

If you are using the original plug lead, which then you connect the same color wires together, then there shouldn't be a problem

mmient said:

That looks like an absorption fridge - Like in an RV. The refrigerant is actually ammonia based. If it is it should be quiet as if I remember, the "compressor" is actually a heat coil that heats the ammonia. I've never soon a portable one before. That's kinda cool...

http://rvrefrigeratorrepair.com/how_it_cools.html

Click to expand...

According to the plate inside the fridge it uses refrigerant 717, and that is ammonia. The Dometic brand is actually found in a lot of hotel rooms.

itinerantbrewer said:

Great project, wfowlks. Thanks for all the pics. I hope you have good results on the overnight temp test.

I think you said the wire frame shelving stood 2.5 feet tall. Could you post the rest of the demensions (with foam and compressor gear on back)? How small a space will it fit in to?

Click to expand...

The enclosure with the compressor on the back is 24 inches deep, 32 inches wide and 33.5 inches high.
You will notice the dimensions are a little larger, because I accounted for 2 inches on each side of foam so that the joints would be closed.


I didn't get a chance to check the temp before I went to work this morning, but I checked it when I got home from work, and it appears that it has raised 2 degrees, the walmart fan has been putting off some serious heat. I just got my temp controller in today, so my plan is to get that wired up tonight and have that to run in there overnight.

If that still doesn't give me the results I want, its on to plan B.

So after thinking, I am going to try to have a fan pointed at the back radiator(fins coming off of the compressor coil) to see if I can increase the cooling capacity of the fridge. Otherwise, on my way home tomorrow I lined up a $30 2 yr old Kenmore compact fridge. I will have to gut it and it will put me over my budget but not by much. Plus its more energy efficient, and hopefully I can sell SWMBO on that aspect.


Side note, The starter I had in my other mini fridge of WLP820 has chewed through its starter, and now I'm letting it settle to decant and step it up. Hopefully I can have the whole build done Friday so I can brew.

wfowlks said:

The enclosure with the compressor on the back is 24 inches deep, 32 inches wide and 33.5 inches high.
You will notice the dimensions are a little larger, because I accounted for 2 inches on each side of foam so that the joints would be closed.


I didn't get a chance to check the temp before I went to work this morning, but I checked it when I got home from work, and it appears that it has raised 2 degrees, the walmart fan has been putting off some serious heat. I just got my temp controller in today, so my plan is to get that wired up tonight and have that to run in there overnight.

If that still doesn't give me the results I want, its on to plan B.

Click to expand...

Thanks for the dimensions.

I didn't realize a fan would be so necessary. thanks for the tip. I'm wondering, however, if it needs to be on all the time (esp if it's the main culprit for generating heat). Could you run it off the lamp wiring, over riding the "door close lamp shut-off switch"? that way, the fan would only run when the temp controller kicked the compressor on. Alternatively, could you scrounge some parts and get a DC computer fan to circulate air? Would that be powerful enough? I imagine those run a lot cooler.

itinerantbrewer said:

Thanks for the dimensions.

I didn't realize a fan would be so necessary. thanks for the tip. I'm wondering, however, if it needs to be on all the time (esp if it's the main culprit for generating heat). Could you run it off the lamp wiring, over riding the "door close lamp shut-off switch"? that way, the fan would only run when the temp controller kicked the compressor on. Alternatively, could you scrounge some parts and get a DC computer fan to circulate air? Would that be powerful enough? I imagine those run a lot cooler.

Click to expand...

The fan in the back on the coils is only necessary because its an absorption chiller. My overnight test was not that successful, and I picked up a newer compact fridge on my way to work for $30. The compressor will be much smaller and I am planning on putting it on top. I was just asking to much for a less than 1 cu foot mini fridge components. The new mini fridge is a 3.5 cu foot. I'll post pics of me dissecting it and taking all the coils out from the inside of it. It should reduce the depth by about 4 inches.

The reason I got the Walmart fan was because I am just starting out and I don't have an old computer fan, and when I used a computer fan in my Keezer, the kegs froze over, because it wasn't moving enough air. With the new fridge the heat put off should not be a problem. The fan is to keep the air moving when the compressor is not on, so that the air does not become stratified, and freeze the bottom of the fermentors.

wfowlks said:

... I'll post pics of me dissecting it and taking all the coils out from the inside of it. It should reduce the depth by about 4 inches...

Click to expand...

Great, good luck with plan B. Keep us posted, I'll keep following. I'm (obviously) looking to rig up something similar.

So, I got the new mini fridge and here are some pix with the door removed. It is a 3.3 cu foot Kenmore compact fridge.

Also earlier today you can probably tell, SWMBO cleaned and mopped the floor, I had to do a lot of cleanup so I would not get yelled at

Back of fridge


Front of fridge


Just a heads up, the foam that they put inside may as well be glue. The lip that was keeping the skin on (the outer metal), was tucked inside, so I had to use a screwdriver to pry it out. WARNING: Use Eye protection. One of my good friends poked their eye out doing something similar. (it may be uncomfortable but what is the price of your sight, plus in all his pix now he has red-eye in the fake one). Also don't try to pry out at eye level. I had also gouged my hands a few times, the metal is sharp when it tears and the screw driver punctures.


WARNING: Use eye protection, and do not operate at eye level

I used a hammer to pull the inner plastic out from being tucked into the metal skin. It made it a lot easier to separate them.



You will hae to remove the freezer compartment (if yours has one) and the temp controller, the freezer compartment just slides out, those screws are decieving. but just look for the big hole for those to slide out.

Finally got the first side up. BE CAREFUL when removing the siding, those copper coils are how the fridge dissipates the heat, and if those get punctured, you have a useless fridge. I used a small screw driver and my hand to trace along where the coils were attached to the skin to break the thin foil holding them there.



Now that I have the first side finished, its time for a home brew. This is my Guter Weizen IPA, its refreshing like a hefe, but the kick and aroma of an IPA


Got the top removed, it was a bit easier, there were no cooling coils in the top for me, But that is not the case for all fridges so be careful. Later I found that the wiring for the temp controller went up that way.


You will notice if you are taking apart a fridge as well that it starts to become flimsy without the metal shell. I finally got all sides taken off and the coils separated. Time to start digging out the compressor base



This is a picture of me the dug out compressor base, so that I can remove just the base, without breaking any coils. The fridge I'm working with has a thin metal frame which everything goes through and I think I'll utilize it later on... Yes also its very messy. I don't have a shop vac, and some of those foam pieces are sticky, and the black stuff is just some clay.

Finally detached, here is a pic of all the important stuff. Compressor, coils, fridge tray.


On a side note, I had parked my car in a fairly legal spot(half in a do not park and half in a good spot), and I had planned to move it, but I got to involved in this project and forgot, now I have a ticket from the "Charm City" aka Baltimore. I can't wait to live in the suburbs and have a driveway. Parking in the city is horrendous.


Back to the main topic,

It took me roughly 2.5 hours to disassemble the compact fridge, and I got roughly 8 scratches/gouges/missing skin off fingers. Its not easy, but for 30$, I'll take that over cycling out frozen bottles every day.

Got the Temp controller finally built. Following the https://www.homebrewtalk.com/f51/ebay-aquarium-temp-controller-build-163849/ thread. However, I will note a few things.

It is very hard to cut the surface of the project enclosure. What I ended up doing was drilling a 1/2 hole in the center of the measured corners, then took the hacksaw blade out of the hacksaw, and sawed the squares out.
I had also tried re-purposing a soldering iron to melt the plastic... that was a disaster.

But here is my finished temp controller. I just did a test and its pretty accurate... Wish I did this for my keezer instead of dropping $90 on a Johnson analog controller. For $34 I have a brand new temp controller that does hot & cold. What a bargain, and it shows me the current temp.



SWMBO was happy with the cleanup job I did the other night, so I was allowed to continue, however next month my student loans start coming due, $800 a month, so I will have to cut back the amount I brew, thank goodness, the lagers take longer, so it won't seem like I'm cutting back

I took a razor blade and clamped it into some vise grips and heated it with a plumbers torch and cut my openings a few inches. Rinse and repeat until done. I can see a soldering iron being messy for that job.

Side note... Do this outside or a VERY WELL VENTILATED area unless you want to glow in the dark one day.

Awesome project. I think I want to go this route for my ferm chamber. I have a question. I was fiddling around with my mini fridge and in my carelessness I ruptured the line that is inside the little icebox. You have it pictured in the last picture in post #23. In my fridge it is actually run between the layers of metal of the icebox. I was just wondering if the unit was pretty much shot or if it could be salvaged?

Did liquid come squirting out? If so it's probably hosed, however I do recall some that's that takes about repairing it by taking it to a local vocational school and having them fix it. However it may be cheaper if you can find another fridge on Craig's list.

If no liquid came out what I would do is get high temp plumbers tape and wrap it with that, I think it's the one in the red container. Then I would use gorilla glue or some sort of epoxy and make a cast of sorts for it

Can you post some finished pics? I'd like to see it with the coils and all. How did you attach them? I am attempting pretty much the same thing this weekend except I am doing a wooden frame for mine.

garcara said:

Can you post some finished pics? I'd like to see it with the coils and all. How did you attach them? I am attempting pretty much the same thing this weekend except I am doing a wooden frame for mine.

Click to expand...

I have the day off today since I work a 9/80 schedule. (M-Th 9 hrs, alternating fridays 8 hrs/day off).

I went to Lowes to look at sheet metal. It is WAY to expensive, aluminum being like 3x the cost of sheet steel. So I just decided to spend $13 and get some tin snips, and use the skin from the fridge as a cover for the coils. I'll be posting pix every 5 pix, because that is how many you can attach at once.

So, started out by cutting the side off of the fridge with the tin snips. Make sure you wear gloves if you use tin snips, not cheap ones either, the heavy duty ones. I got bit by a piece of the metal that came up on the corner. But like a real man, I don't bleed, I just swear a lot. But really, it was not fun to deal with, so just be careful.


I got the siding cut, and I used the back of a hammer to just run along it and scrape off all the excess foam. I suppose a metal spatula would have done the same thing, but I don't have a lot of tools.



After trying to bend the freezer flat by hand, I noticed that it was arching the middle, where I wasn't holding it, which can be bad if it pinches the coolant line. So I laid the compartment down on a table, across a board of wood. Held down the center portion while I bent it flat. If you have a workbench you may want to use another piece of wood to hold it in place, I would just caution though, that if you do that you can't see if you are pinching the coolant lines.


Here is 1 side flattened.


Here is the other


I am going to try to fit it inside the hole that I unmounted the other one from and lay it in the separation between the rack that I used inside and the top layer of insulation. More pix to come shortly stay tuned!

Nice build I have been looking at using a window air conditioner but this might be more efficient and cost effective.

The idea of compressing gases causing them to cool sounded strange so I looked it up on HowStuffWorks, so this is the condensed version. Compressed gases heat up not cool, and the cycle is as follows according to HowStuffWorks:
1. Refrigerant (usually ammonia gas) is compressed which heats it up and can cause it to condense into the liquid phase.
2. This gas/liquid flows through the heat exchanger on the outside of the fridge to cool it with ambient air.
3. The gas then flows through the expansion valve which rapidly depressurizes (if thats a word) it causing extreme evaporative cooling (can reach -27*)
4. This expanding and cooling gas flows through the heat exchanger on the inside of the fridge cooling down the internal air, the cycle repeats as the compressor draws air from the internal heat exchanger.

Hopefully someone who does HVAC will throw their two cents in.

Keep the pics coming, great thread.

RTL said:

Nice build I have been looking at using a window air conditioner but this might be more efficient and cost effective.

The idea of compressing gases causing them to cool sounded strange so I looked it up on HowStuffWorks, so this is the condensed version. Compressed gases heat up not cool, and the cycle is as follows according to HowStuffWorks:
1. Refrigerant (usually ammonia gas) is compressed which heats it up and can cause it to condense into the liquid phase.
2. This gas/liquid flows through the heat exchanger on the outside of the fridge to cool it with ambient air.
3. The gas then flows through the expansion valve which rapidly depressurizes (if thats a word) it causing extreme evaporative cooling (can reach -27*)
4. This expanding and cooling gas flows through the heat exchanger on the inside of the fridge cooling down the internal air, the cycle repeats as the compressor draws air from the internal heat exchanger.

Hopefully someone who does HVAC will throw their two cents in.

Keep the pics coming, great thread.

Click to expand...

If you were going to use a window ac, you would be bound to put the fermentor by the window, (which I don't have many of), but if you just had it in the house it generates A LOT of heat, and consumes way more energy than a mini fridge.

That is pretty much correct about the modern fridges and is the basic principle behind how the new one will operate.

Here's a snipit of what I remember from my days in thermodynamics. When the gas is compressed, it causes it to lose energy (heat). The gas being brought the the expansion chamber into the interior cooling coils becomes endothermic (heat absorbing), as it has more volume to expand to, drawing the heat from the surrounding environment. After it absorbs the heat, since it is a closed system, it tries to expand, and is pulled by the compressor through the cooling coils (the copper tubes along the skin, to dissipate some heat with the surrounding environment. And is then brought back into the compressor to start the cycle again.

The older one worked a bit different, and the best resource I found was wikipedia.

http://en.wikipedia.org/wiki/Absorption_refrigerator#Single_pressure_absorption_refrigeration

IMO the new mini fridge being energy star compliant, is the best option for my situation. I like it because it gives off less heat and is a bit quieter.

So I built a little guard out of wood to hold the compressor up at the right hight, and I anchored it to the bottom rack. Its turned upside down so that its easier to screw in



I tried to screw it in with the aluminum guard that was on it, but the right side was too distorted from when I initially dismantled the fridge.



So I decided just to remove the encasing. To do so I just used the tin snips and cut a wide wedge VERY CAREFULLY to each element, and carefully moved it out of the way. I did manage to get stabbed a few more times from the metal slivers. I think it went all the way to the bone of my thumb this time but it was narrow so luckily I don't need stitches. So learn from my experience



Cut out the metal, and got it flipped over to the right side. Did it carefully because I didn't want to bend/break anything, and they weren't protected by the aluminum guard that I just removed.



I ended up having to remove the top portion to slide it in, as I tried to get the cooling component in via the slit that was from the previous fridge, but it was to small, and I didn't want to risk bending the coil and breaking it. I'd rather pay the $2 for another bottle of liquid nails.


Got the thermostat and probe attached to the freezer compartment. Next is to secure the coils to the side, and then re-glue the top.

Lesson: If your layout is similar to mine, wait till the end to attach the top. It will save you some hassle.

But anyway back to building. More pix to come

wfowlks said:

If you were going to use a window ac, you would be bound to put the fermentor by the window, (which I don't have many of), but if you just had it in the house it generates A LOT of heat, and consumes way more energy than a mini fridge.

That is pretty much correct about the modern fridges and is the basic principle behind how the new one will operate.

Here's a snipit of what I remember from my days in thermodynamics. When the gas is compressed, it causes it to lose energy (heat). The gas being brought the the expansion chamber into the interior cooling coils becomes endothermic (heat absorbing), as it has more volume to expand to, drawing the heat from the surrounding environment. After it absorbs the heat, since it is a closed system, it tries to expand, and is pulled by the compressor through the cooling coils (the copper tubes along the skin, to dissipate some heat with the surrounding environment. And is then brought back into the compressor to start the cycle again.

The older one worked a bit different, and the best resource I found was wikipedia.

http://en.wikipedia.org/wiki/Absorption_refrigerator#Single_pressure_absorption_refrigeration

IMO the new mini fridge being energy star compliant, is the best option for my situation. I like it because it gives off less heat and is a bit quieter.

Click to expand...

Makes sense. The whole unit would have been in my garage but it's hot enough out there already and I would like it to be efficient. Thanks for the info, keep it coming.

SUCCESS!!!!

So the temp dropped to 5 degrees overnight. And since I took the picture it has dropped another 0.1. Brewing starts on Wednesday.

One thing to also note, since I raised up the compressor a bit, the fridge kept leaning back. So what I did was I screwed a wooden plate onto the back kind of like a kick stand.



The new enclosure on the back, adds 8 inches to the depth. This could be reduced if you put the compressor closer to the back panel. I just wanted to give it as much air as possible.
If I had a taller rack, I would probably put the compressor unit below.

Also, I felt the side of the fridge, using the metal to cover the coils allows it to dissipate heat better. The panel was warm to the touch but not hot.

So the total dimensions are:
28" Deep, (20" foam enclosure + 8" compressor mount)
32" Wide
30" Tall