Son of a Fermentation Chiller Hack - advice needed

[OrangesOfCourse]

Hey guys,

Its been a while since we've been able to brew anything. Holidays are coming up so we wanted to brew a few beers. For the last brew we had built the Son of a Fermentation Chiller but i got tired of replacing the ice all the time. My chiller has to stay in the garage so it's a process that has to be done often. I decided to use my mini fridge to take over the cooling duties. I've removed the partition inside the chiller and mated the fridge with 2 holes. I wanted to know if my principles are correct and if there is a better way. Should I not even bother with the 2 holes and just make a cutout for the fridge?

I live in Texas so the temp outside get pretty hot and hotter still in the garage. I wanted to make this as efficient as possible and be able to maintain 59-64 during the hottest parts of the day. I know the insulation inside needs some work and that's already on the list of things to do. Is there any other way for me to improve the design?

Any advice would be helpful.

Mini fridge mated to son of a fermentation chiller:


Look inside the chiller. Top fan blows air from the fridge into the chiller and bottom fan blows air from the chiller to the fridge.

I know its dirty inside but i'm still in the process of getting it ready for the brew.

 

[FuzzeWuzze]

Should work just fine, quite a bit of cold air is going to 'leak' through the fan blades when they are off though since they are so low(cold air sinks).
So you might want to just keep an eye to make sure it doesnt get too cold. You may need to just modify your temp controller to be a STC1000, so that you can properly turn on and off the fridge.

I assume right now your method of temperature control is turning on and off the fans.

 

[OrangesOfCourse]

Should work just fine, quite a bit of cold air is going to 'leak' through the fan blades when they are off though since they are so low(cold air sinks).
So you might want to just keep an eye to make sure it doesnt get too cold. You may need to just modify your temp controller to be a STC1000, so that you can properly turn on and off the fridge.

I assume right now your method of temperature control is turning on and off the fans.

Yes, right now i'm controlling the temp by turning the fans on/off. I was looking into setting up a relay to turn the fridge on/off (https://www.homebrewtalk.com/f51/diy-temp-controller-build-133364/) but I wanted to see if this system would work before building that. Should i keep the fans in place after installing the relay? Would that be the more efficient way? I'm also worried that the relay will have the fridge turning on/off too often, thus killing its lifespan. Am I worried about nothing?

 

[rjmaster19]

I'm in Houston too, so I feel you temperature pains...

I don't know if a thermostat keeps from cycling the fridge too often. But I know for sure you can adjust that with a STC1000. But yes, if the thermostat cycles the fridge too often it will shorten the life of the fridge.

Also, from your pictures your fans look like they are located side by side with only 4-6 inches in between. I would think this would just make the air cycle between the two fans. Don't you need some kind of divider to keep that from happening?

I'm looking to do something similar in the near future. The small cube fridges are cheaper and seem to be more available on CL. So I'm interested in your results.

 

[OrangesOfCourse]

I'm in Houston too, so I feel you temperature pains...

I don't know if a thermostat keeps from cycling the fridge too often. But I know for sure you can adjust that with a STC1000. But yes, if the thermostat cycles the fridge too often it will shorten the life of the fridge.

Also, from your pictures your fans look like they are located side by side with only 4-6 inches in between. I would think this would just make the air cycle between the two fans. Don't you need some kind of divider to keep that from happening?

I'm looking to do something similar in the near future. The small cube fridges are cheaper and seem to be more available on CL. So I'm interested in your results.

Thanks for the feedback.

I was looking into the thermostat to see if it offers compressor protection and it seems like it does.

3. Compressor Protection
This thermostat provides a 3.5 minute delay after shutting off the
cooling system before it can be restarted. This feature will prevent
damage to your compressor caused by rapid cycling. It does not
prevent a rapid compressor restart due to short power outages

Would 3.5 mins be enough?

Really good point about the air cycling between the fans. I do have extra foam that i can make a input "pipe" that feeds air from the top of the box. Let me try that out and see if it affects the cooling.

 

[rjmaster19]

The pipe is definitely a good idea. I believe computer fans "push" harder than they "suck", so maybe the air from the fridge should be pushed into the pipe.

I keep have my keggerator on a 5 minute delay. I would think 3.5 would be enough.

 

[FuzzeWuzze]

Thanks for the feedback.

I was looking into the thermostat to see if it offers compressor protection and it seems like it does.



Would 3.5 mins be enough?

Really good point about the air cycling between the fans. I do have extra foam that i can make a input "pipe" that feeds air from the top of the box. Let me try that out and see if it affects the cooling.

The STC1000 has a max of 10 minute compressor delay, that is what most people set theirs too for fermentation or kegerators/keezers. Honestly i wouldnt bother with a Home Depot hacked together one when you can build a much nicer STC1000 for the same price.

If your measuring your wort temperature properly, and not the temperature of the air inside, and your insulated properly then it should take well over 30 minutes to an hour for your beer to drift the 1-2 degree's it might take to trigger your fridge back on. The 10 minute setting is more just a safeguard, in case say you forgot to put the lid on one side and it just let all the cold air out.

Buy this
http://www.amazon.com/dp/B00862G3TQ/?tag=skimlinks_replacement-20

Just make sure when you buy a STC1000 that its the 110V version and not the 220V version they use in China/EU. A few people on Ebay got bit by that.

 

[aphid_rancher]

The STC1000 is a better option than using a home thermostat like in your picture for several reasons. The most important is that the relay in the thermostat is small and intended to carry enough current to switch a bigger relay like would need for a refrig. I made a temperature controller with a thermostat and a simple circuit with a bigger relay and a wall wart. It works but I ended up making another with an STC1000.