Diy Coolroom For Under $100 (failed)

[outbackbob]

Hey Guys,

My project this weekend was to build a DIY coolroom for fermenting in.

My aim was to be able to build a coolroom for under $100 that was capable of getting down to lager fermenting temps.

I wanted to use my existing fridge/freezer, as I figured that the freezer was running, but not being utilized, so I should be able to do something with that.

I picked up a sheet of 75mm insulating foam for $50 from a building supplies place. I cut this up to make a coolroom 1200 x 600 x 700.

I cut a hole in the door of my freezer and run some 90mm polypipe from the freezer to the top of my coolroom, with a 8cm computer fan mounted in the freezer blowing air out and one at the other end of the polypipe in the coolroom sucking air in.

I also made a thermostat the weekend before that I planned to use, but just to test how cold I could get it to go, I hooked the fans up to the power to run non stop and left it for an hour to see how cold it would be.

To my dissapointment, the temp had only dropped by about 2 deg F.

See photos of my setup:

Has anyone attempted something like this before and had any success? If so... Any pointers you can give me?

Cheers,
Leighton.

 

[brenthor]

You would need to add an air return to the freezer

 

[Adamt]

Yep... if the freezer is sealed and the cool-box is sealed... won't be possible to move air (continuously) from the freezer to the cool-box.

 

[barls]

you might do better with copper pipe, glycol and a pond pump.

 

[loikar]

Has anyone attempted something like this before and had any success? If so... Any pointers you can give me?

Cheers,
Leighton.

With the freezer door shut, what air are the fans pulling into the cool room?
With no air coming into the freezer, there's little air going out to the cool room (kinda like trying to rack to a secondary with your fermentor lid on tight and the airlock hole bunged up), and if you bring outside air into the freezer....expect to be defrosting that baby on a regular basis and you leccy bill to go up a fair whack.
I would try leaving it on overnight, see what it's like after 12 hours.
Also, that pipe is gonna need a heap more insulation...

just my 2c

Awesome Idea though!

Fingers

 

[QldKev]

Agreed with the rest here. I do think this solution will work.

A. you need a return line back into the freezer to get air flow.. I would use both fans on the return line as you need to lift the air back up to the freezer, the cooler air will settle down hill OK.

B. The feed line should be from the bottom of the freezer to the top of the cool room.

C. Return line at the top of the freezer. bottom of the cool room to ensure circulation.

D. I would have the pipe into the cool room at one end, and the return line at the opposite bottom corner.

E. What refrigerators do is to extract heat from things. Technically they don't insert coldness, what they do is to suck out the heat. When you put a bunch of your room-temperature groceries in your fridge the fridge starts sucking the heat of them and sending that heat to the coils on the back or the bottom of the fridge. It takes the heat that's on the inside and sends it to the outside. So you may be better off ensuring your freezer is at least half full. Even with just water bottles, it will work more efficient..

F. I would also consider insulating the floor as you don't want extra heat be absorbed into the cool room.

QldKev

 

[Pollux]

For under $100, couldn't a secondhand fridge and a fridgemate be a better option??

 

[chappo1970]

For under $100, couldn't a secondhand fridge and a fridgemate be a better option??

Well actually I reckon no. A fridgemate is about $70 to $80 by the time you buy all the bits and pieces that leaves with $20 - $30 buckeroonies to buy a fridge. I get ya point and no offence Pollux but his idea is brilliant in it's application. By running only one fridge and by utilising the freezer as the chiller and obviously the fridge for kegging. Kinda two birds one stone, yeah? Brilliant :icon_cheers:

As everyone has suggested above definitely need return air so that the air pressure is neutral. Also think about have a second fan there so you have one pushing the airout of the freezer and one pulling air into the freezer via the return. Also place the return air eg the one running back to the fridge as high as possible and the cold air closest to the bottom.

Also try to think of a more effective heat exchange method rather than just blowing air in and out of the freezer. Think herms think car radiator. Best I can think of ATM is some metal screening to act as an exchange and disturb the airflow. Add a bit of turbulance like an immersion chiller so more air contacts the cooler air/metal etc...

I really think your on to something there just needs tweaking here and there.

my 2c

 

[browndog]

It won't work, you won't get enough cooling from the freezer into the coldroom to chill your wort and keep it at a specific temp. You would be better off buying a temp control coupled with a fridge or air con unit.

cheers

Browndog

 

[big d]

Heres another idea for you Bob that i saw some years ago.Take one working fridge and one dead fridge and cut a large hole between the two of them and join them together.
You have now doubled your capacity and quite cheaply i might add.Just add a temp controller and your away.

Cheers
Big D

 

[mika]

Other people on the forum have done exactly what you've done. Not sure how successful it was though.

 

[real_beer]

Heres another idea for you Bob that i saw some years ago.Take one working fridge and one dead fridge and cut a large hole between the two of them and join them together.
You have now doubled your capacity and quite cheaply i might add.Just add a temp controller and your away.

Cheers
Big D

Yeah I saw something similar about 5 yrs ago, the guy took the door off his fridge and built a cabinet out of marine ply on castor's to fit the opening, then insulated it and fitted a seal, hinges, and clasp. He reckons it works great if you don't need to access inside too frequently.

 

[Justin]

I still think a second fridge would have been far simpler and more effective. FWIW you dont need a digital Fridgemate controller either, there are cheaper options like a traditional mechanical thermostat. I used mine from Tobins for a long time, it was $40. And I have no doubts that you can find a fridge/chest freezer for $60 or less.

Seriously, ask everyone you know if they have a spare fridge etc. You'd be surprised how many people have an old fridge in the garage that they just haven't got round to selling/throwing out after they upgraded. Fridges are big and cumbersome to dispose of, so they tend to sit there until they really have to go. Ask around and watch the papers.

But the above comments are right, if you expect that box to cool you need to have air going back to the freezer. It will be interesting to see what your kegging fridge part drops down to as well though, as many fridges are cooled by the freezer compartment above them (a draft down the back transfers cold air). Given your going to be sucking cold air out of the freezer the fridge is probably going to run non stop. So I'm kind of tipping that either the fridge compartment will freeze because the fridge is running so much or it wont get cool enough.

Anyway, get back to us and see how it goes with the fixes.

 

[matti]

Interesting!?

I am curious if the cooling would be sufficient even with "a return airflow."

The refrigerator would be going non stop (24/7) as it trying to cool a bigger volume of air.
I am not a "fridgy" but, one would think it would be cheaper to run a good insulated chest freezer, then this kind of set up in the long run.

Keep us posted when you have found a solution.

Matti

 

[Justin]

Interesting!?

I am curious if the cooling would be sufficient even with "a return airflow."

The refrigerator would be going non stop (24/7) as it trying to cool a bigger volume of air.
I am not a "fridgy" but, one would think it would be cheaper to run a good insulated chest freezer, then this kind of set up in the long run.

Keep us posted when you have found a solution.

Matti

Agreed. I'm not convinced yet that the freezer will have the capacity to do it either, hence my suggestion of just getting a second fridge that you know will have the ability to do the task.

 

[fraser_john]

At one stage I had something similar, a chest freezer with the foam fermenting box built on top of it, with two computer fans, one forcing air in and the other forcing air back into the freezer. Worked a charm...but....with the fermentation bubbling away happily you end up creating a lot of moisture. The chest freezer ended up collecting more and more ice as time went along. I have photos of the whole thing somewhere.....I'll try find them tonight and post a follow up.

 

[ArnieW]

I've gone with a slightly different approach -

1 old (dead) chest freezer
1 computer fan coupled to a PC cooling radiator
1 pump to pump cold water through the radiator
1 temp controller (fridgemate)
1 cooling plant (in my case it is an ice bank chiller, but the freezer might be sufficient)

The old freezer was hacked about to get rid of the compressor and shelf. This allows 8 kegs to fit inside or fermenters and kegs together. The idea with the freezer is that it makes for a ready made insulated cabinet.

Cold water is pumped through the radiator from the ice bank (0 deg C water) and returns back to the ice bank. The fan on the radiator blows cold air into the freezer cavity. Fan and pump are controlled by a fridgemate.

I'm in Melbourne, and during the peak of the heat wave I was able to maintain 17-20C inside the 'cellar'. This was during the four days of 43-45 degree weather and the garage temperature exceeded 40 degrees. Now that the weather is more reasonable, I have no trouble keeping the cellar at lower temps although I've not yet wound it down for lager fermenting. I can hold it at roughly 20C below ambient with this setup. I intend to begin lager fermenting with it in the next month or so and continue through to October or November. In December when the weather was quite mild I had no trouble holding the cellar at 11C.

For those interested I've got a blog site that documents building the bar and testing performance of the cellar. The bar building bit starts at the linky here:
HERMAN machine blog

 

[oldbugman]

Check out the lama brewery.
Besides being a big kick ass brew rig, he has a similar setup to what your trying

http://www.lamabrewery.com/Various%20Toys.htm

 

[outbackbob]

Thanks for the replies guys.... Seems I maybe should have posted my idea here first

I've gone with a slightly different approach -

1 old (dead) chest freezer
1 computer fan coupled to a PC cooling radiator
1 pump to pump cold water through the radiator
1 temp controller (fridgemate)
1 cooling plant (in my case it is an ice bank chiller, but the freezer might be sufficient)

This was going to be my next attempt if I can't get it working... I was thinking a copper coil in the freezer with glycol running through it and piped down to a radiator in the coolroom could do the trick.

Anyone know where to buy glycol and how much? Anyone got a watercooling rig for their PC they don't want?

Thanks.

 

[Ducatiboy stu]

Glycol is what goes into car radiators..

Just go to any Auto spare parts place and buy it...