Upgrading My Ferm box

[tolip_ck1]

My job does not allow me to replace my frozen bottles of water as often as I would like in my fermentation box. So I am going to upgrade.....because I can

I have been told a-lot about Peltier inefficiencies, But I have also been told I can buy beer at a store. Neither seem to faze me so I decided to change things up a little bit. I'll let you know how it works.

 

[MalFet]

I've got a peltier cooled box. Works great. Good luck!

 

[tolip_ck1]

Well installed them and it is running (24 hours), however I am only getting it down to 67, about a 10deg drop where I live, not sure why. I just turned 2 of the 4 units off, maybe my power supply is weak.

Any ideas?

 

[MalFet]

Well installed them and it is running (24 hours), however I am only getting it down to 67, about a 10deg drop where I live, not sure why. I just turned 2 of the 4 units off, maybe my power supply is weak.

Any ideas?

Peltiers are finicky. How are you getting air off of the hot side?

 

[tolip_ck1]

Just like the picture above, you are seeing the hot side with the heatsink and fans.

 

[tolip_ck1]

http://cgi.ebay.com/ws/eBayISAPI.dl...witem=&sspagename=STRK:MEWNX:IT#ht_500wt_1156

This is what I bought.

 

[tolip_ck1]

i put thermal grease on both sides of the cooler, hot and cold side heat sinks, was that a mistake?

 

[MalFet]

It would certainly be worth running your meter across your power supply to make sure that things are working properly there. How's your insulation? Noticed any changes since you turned off two of the plates?

 

[tolip_ck1]

Yea, turning them off made it warmer! I may need to beef up the insulation. I am getting a lot of condensation of the cold side heat sink. I was expecting it to get cold enough that it would freeze but it is not.

 

[gunner65]

I have one in my ferm chamber and it can get down to about 60F in a 72F room. I would think four of them should be able to freeze.

 

[tolip_ck1]

You would think! I have added some insulation and tightened things up but I still can’t get less than about 62 deg. They work good, here are things I have done.

1) Took apart again turned them on and froze drops of water on them, (they work) 17deg infrared temp measurement.

p.s. don’t touch them I "double dog dare you!!", or lick them for that matter.

2) added thermal grease to both sides of wafer.

3) added more insulation and closed of the box better.

4) checked voltages and amps all check out.

I am hoping that my thermal grease will cure and I get better cooling out of them, I do have a lot of condensation and I think that maybe it is insulating the heatsink, but it is not frosting up at all.

It is good enough to ferm but I was expecting more.

 

[gunner65]

Any updates?

 

[tolip_ck1]

Yes I think my coolers are not efficient do to some corrosion I found on the heat-sink. I "rebuilt" one of them by taking it apart and found that the heat-sink may have had some oxidation, so I polished it up and added better grease. It got the heat sink a lot colder, so I am going to do that to the other 3 and see what happens.4

 

[gunner65]

Good news. I robbed mine out of one of the little counter top wine coolers but it appears to be of about the same size as yours. I was thinking that maybe you were not supplying enough current but I checked the rating on mine and it is only 1 amp 12 v. So you only need about a 5 amp supply for yours.

 

[tolip_ck1]

I figured out how to use my multi meter they are drawing about 3 amps each, my power supply should be enough.

Update, I took apart and made a mirror finish on the hot and cold sides of the heat-sink. I then made sure that the Peltier's were 100% clean and added high quality thermal grease. They are working a lot better now!

 

[MalFet]

Very cool. Thanks for posting tolip_ck1. People describe such different results with peltiers, and I have never been able to adequately explain why. Sounds like this might be a major factor. How much below ambient do your temps get now?

 

[tolip_ck1]

Yes they cool much better, it doesn't seem like it in the temps of the box, still only a 10 deg drop from 75 to 62 which will be fine for an Ale. One thing to take in account is that I am running this at the moment in my garage today it was 76 deg and 87% humidity (Texas). The coolers took about 1/2 gallon of water out of the air in 1 hour so I think I am losing a lot of energy dehumidifying my obviously poor sealed box. Once I get another quieter fan I will change it, seal it better, and move the box inside where at the moment the temp is 76 but only 53% humidity.

Going to add a water removing device in the box to help capture some of the humidity so I think it will continue to improve my temps. Really I am just looking to keep one extra 5 gallon ale cool during fermentation I can only do 2 at the moment in this thing

 

[KingKegII]

Ah, the woes of fermenting in H-Town! Very cool (no pun intended), I also like the pic of the cooler you have w/ the glass doors. For your pelt cold box, you could try putting in some DampRid, see if that helps.

 

[tolip_ck1]

Exactly what I am going to do. I have an old coffee pot, I put a coffee filter in, fill with DampRid, (cheaper if it is not packaged/Bulk) and dump water out of said pot every once in a while!

 

[tolip_ck1]

Added the "aquairm controller" temp in pic is actually 24c, I just turned it on. This is the first run inside with loew humidity.

Cool baby cool!

 

[brboland]

Any update how this is performing now that you are in less humidity?

 

[tolip_ck1]

The thermal grease took a day or two too "cure", I added another fan to blow more volume across the cooling fins. It works a lot better, I have not added any "damp rid" yet, and I have not actually tried to ferment. Problem now is that it will freeze up and I lose efficiency because of the insulating properties of ice/frost. With that said it keeps the box at a nice 60deg, in a 75-80 deg house.

 

[wedge421]

I was thinking of doing this setup myself. Let us know how you get it working! How much money would you say yo have into this setup?

 

[brboland]

Man I was really hoping to use peltiers to cool a box for lagers, doesn't sound like it will happen.

 

[tolip_ck1]

I had the ferm box I made a long time ago from another DIY post on this site (can't find it at this time).

Box,
1 Sheet of 3/4 rigid foam 25$ (Guess only)
I used reflective tape 10$
A roll of foam tape 10$

For the above box I used a basic thermostat computer fan (12v) and Frozen jugs of water.

Removing the above I replaced with 4 peltier coolers purchased on e-bay (2 for 20$) and a 12v 15A power supply for 30$+shipping (45$). I added 2 computer fans that were laying around, one to cool the power supply and another to run across the cold sides of the peltiers fins. (that is 3 inside, 1 outside) The peltiers i bought had everything, I did have to do some rewiring and spend an additional 10$ on thermal paste.

I had another aquairum DIY box which now controls the new power supply,

Not including that, cost to make the box is about the same as cost of buying a fridge I am not sure what it cost to run my cooler, one slight benefit is that it is almost silent.

I made it...because I could. I do like it and will use it as a 3rd place to ferment, It is very light maybe 10# and is easy to move around.

 

[tolip_ck1]

Man I was really hoping to use peltiers to cool a box for lagers, doesn't sound like it will happen.

I think if I doubled everything and made a better box maybe, but you might as well find a small fridge that fits your carboy or bucket for lagers. You could spend a lot more money and buy much bigger peltier coolers mine run on about 3 amps each.

 

[tolip_ck1]

Box seems to be working very good, House temp is 80 (53%) humidity.

Carboy 4.5 Gallons IPA temp is holding at around 18.5 deg C +.5 deg C. Run time to maintain temp is around 10 min every hour. Nice to have a third place to ferm!

This will be an overflow Ale box.

 

[timbudtwo]

I have never had good personal experience with using peltiers. The only one that I ever got that worked well was a cheapo surplus 1.5 inch square unit that I thought of putting on my computer.

The thing to remember, peltiers work off of differentials.
I noticed a couple things in your design that could certainly help:
1. Get some small fans on the inside heatsinks. You want to make sure that the cold side is in direct contact with what you are cooling (like a computer chip) or that it's getting moving air across it. This goes the same with the hot side. You have a fan on there for a reason!
2. Bigger heatsinks on both sides. Aluminum is a great conductor of heat but it also likes to hold heat. It is also not very malleable when compared to copper. Thinner vanes = greater thermal transmittance through the air you are forcing across the hot side. However moving to copper would probably not be cost effective.

Also, there are different types of peltiers you can get that are manufactured differently. I did not notice if you mentioned if you had the sealed or unsealed variety.

I also cannot clearly see how you are insulating the hot from the cold side. You want to make sure that differential stays separate! I see some gray foam and perhaps some silicone sealant? I would look into trying a couple layers of neoprene. A Closed cell foam will insulate a lot better than silicone. But if you are using the silicone as a sealant, insulator, and a glue then there is not much better than that.

 

[tolip_ck1]

Thanx for the info,

The units I am using were removed from an in car cooler I think, all the parts came together, from the e-bay purchase.

This is guy who sold them and the exact thing I purchased.

http://www.korhonen.ca/Peltier Cooler Fun.html

It is working as well as I expected I am sure I can make it preform better but I am happy at the moment.

One thing that helped HUGE was adding another fan to cool the cold sides, (which you mentioned).

Also starting with with the Carboy at the correct temp adds a lot of cold mass, which is what I also did.

 

[timbudtwo]

This is a commercial fermentation box cooled via a peltier. Sometimes called a fridge. This one is a bit small for your purposes, but you can see the inside has a couple fans on it to get the cold air movin.

...

It is working as well as I expected I am sure I can make it preform better but I am happy at the moment.

One thing that helped HUGE was adding another fan...

Also starting with with the Carboy at the correct temp adds a lot of cold mass, which is what I also did.

Ahh, good to know. I only read about the first page and a half.

Yeah, making sure the stuff you put in there is not warm will certainly help keep temps low.