My Nu Cool Fermentation chamber! (nucool)

[physast]

I have been waiting for one of these to pop up on craigslist and it finally happened. It's the 2.8 CF Haier nucool small fridge.

I got it home last night, plugged it in and set it to the highest setting to see what would happen. I put a thermometer inside a glass of water to see what temps I could reach.

This morning I was at 42F, after roughly 7 hours. This was on the max setting and I am sure it was running the entire night. I turned down the 'temp control' a notch to see what that would do. I will check it when I get home this evening.

I also plugged a killowatt meter in to see what kind of electricity this thing uses. After 10min it was showing roughly costing $109 a year. This is running full blast and of course only 10min of data. I will also take a look at this when I get home and update.

So I have some questions for everyone who has experience with these fridges.

1. What did you use to cut the foam on the door?
2. Is a temp control necessary?
3. Anyone else use a kilowatt to see energy usage?
4. Any tips, tricks or recommendations?

Happy fermenting!

 

[MalFet]

1) I used a dremel with a rotary cutter attachment, but with some patience and a serrated blade I'm sure you could make it work without one.

2) Yep. A temp controller will always be necessary with any kind of fridge.

3) Nope,but your estimates sound high. Like you said, in actual use scenarios the plates won't be running anywhere close to constantly, particularly if you are an ale brewer primarily. The nucools use significantly more energy than traditional compressors, but it's still a relatively small amount.

4) A pin lock corny will fit in there, too, but a ball lock won't.

 

[physast]

1) I used a dremel with a rotary cutter attachment, but with some patience and a serrated blade I'm sure you could make it work without one.

2) Yep. A temp controller will always be necessary with any kind of fridge.

3) Nope,but your estimates sound high. Like you said, in actual use scenarios the plates won't be running anywhere close to constantly, particularly if you are an ale brewer primarily. The nucools use significantly more energy than traditional compressors, but it's still a relatively small amount.

4) A pin lock corny will fit in there, too, but a ball lock won't.

Yeah my estimates were also using very minimal data collection. After a month of use I will be interested to see what kind of data I get.

I might also pick up a temp control, but want to see if I can maintain a given temp without one. Once this temp is dialed in I plan on filling my bucket with 5 gallons of water, putting in the fridge and seeing what happens. Of course the bucket won't be fermenting but it will give a good idea +-(5 -10) deg F.

What temp do you keep your fermentation fridge for ales? Not the temp of the wort, but actual fridge temp. I was thinking 55F would be good.

 

[MalFet]

YWhat temp do you keep your fermentation fridge for ales? Not the temp of the wort, but actual fridge temp. I was thinking 55F would be good.

That's the problem...it doesn't work like that. Fermentation is exothermic, and likewise there is no reliable way to correlate fridge setting to wort temperature or ambient temperature to wort temperature.

At different stages of fermentation, the difference between ambient and wort temperatures will vary by 5-8ºF. That isn an acceptable range for me, hence the temp controller.

If you just set the fridge dial to an ambient, say, 60ºF, you'll get the worst of all worlds: the wort will be nice and warm during active fermentation, but then will rapidly drop as soon as things slow down. In reality, you want exactly the opposite: controlled temps during active fermentation followed by a gradual rise. If you let the temp drop like that, you encourage yeast flocculation. That's a recipe for poor attenuation.

 

[physast]

That's the problem...it doesn't work like that.

At different stages of fermentation, the difference between ambient and wort temperatures will vary by 5-8ºF. That isn an acceptable range for me, hence the temp controller.

....That's a recipe for poor attenuation.

I am using a glass of water like I do in my keg to set the temp. I was hoping I could get away with making the temp of the water hit 55F then the wort with active yeast would be around 60 - 65F which is not bad for ales. Once the activity drops, the wort would then slowly cool to around 55F.

So what you are saying is this is not good, right? If I had a temp control and set the probe in a glass of water to get a constant temp wouldn't that do the same thing? Or do you attach the probe to the bucket and take actual wort temp?

 

[MalFet]

I am using a glass of water like I do in my keg to set the temp. I was hoping I could get away with making the temp of the water hit 55F then the wort with active yeast would be around 60 - 65F which is not bad for ales. Once the activity drops, the wort would then slowly cool to around 55F.

So what you are saying is this is not good, right? If I had a temp control and set the probe in a glass of water to get a constant temp wouldn't that do the same thing? Or do you attach the probe to the bucket and take actual wort temp?

You want the probe on the bucket. Some people put it in the bucket, using a thermowell, but that's actually not completely necessary.

Yeast produce heat. There will be a significant temperature difference between a glass of water and your wort.

 

[physast]

I guess a temp control is on my wish list! Might aswell do it right.

I have not looked at the actually peltier device in this system, has anyone done this yet?

I assume it has at least a heatsink - peltier - heatsink device with a fan to blow cold air from the heat absorbing side in to the fridge.

Has anyone tried to upgrade the fans? If there is not a fan on the outside of the unit dispersing heat from the hot side heatsink this might also be a good upgrade.

Anyone done modifications to the nucool other than temp control and cutting the door foam?

 

[physast]

I just got home and checked the temp. Still at around 42F.

The killowatt meter has now been reading for 8 hours and predicts the annual cost to be around $133!! it was at roughly 1.3Kwh in 8 hours.

 

[ahave]

https://www.homebrewtalk.com/f51/nu...r-ebay-aquarium-temperature-contoller-257637/

See my post in the DIY section. I used an external thermostat although you could easily modify the existing hardware to set the temp for fermentation. I used the original wiring for the thermostat for my build so that I wouldn't have to drill any holes.

The door came off with a little force. I used an exacto knife to cut the plastic, then a 'pry bar' to get the door off. Once you get a crack going the foam rips with ease. Becareful not to bend the metal door in the process. (I took the door off the hinges to work on it)

Both pairs of heat sinks have dc fans mounted to them. You could easily upgrade the fans if need be.

 

[physast]

https://www.homebrewtalk.com/f51/nu...r-ebay-aquarium-temperature-contoller-257637/

Do you have a detailed write up of what you did with the temp control? I am not an expert at wiring. I did take off the back and noticed that the circuit board has a empty 'DC' slot (see pic). Could this be used to wire up the temp control?

I just cut the foam off the door. This was so much easier than I expected. I can't wait to get his going. I have been fermenting my beers at 80F for the past three years.

 

[ahave]

The ntc is where the temperature reading comes in. The dial on the inside simply adds a resistance to the thermister output which is monitored by the board and if it is under a certain amount value it will engage the cooling device. (more heat = lower resistance)

In theory you could add a resistor to the NTC measurement to trick the system into running with a warmer operating temperature. The problem is you don't really know the temperature it is set at (using the dial) so your fermentation temperatures would be hard to set. I found it easier to just do the normal external thermostat ebay controller tied into the 110V input to control the fridge. There are quite a few threads explaining how to do this on the forums, but if you have any questions let me know. (I flush mounted the ebay controller to the fridge itself)

I tricked the fridge into thinking it always needed to be running by removing the NTC wire and replacing it with a fixed resistor. I then ran the NTC wire into my ebay temp controller as the temperature. The fridge has been purring away at 65F since..

 

[physast]

The ntc is where the temperature reading comes in. The dial on the inside simply adds a resistance to the thermister output which is monitored by the board and if it is under a certain amount value it will engage the cooling device. (more heat = lower resistance)

In theory you could add a resistor to the NTC measurement to trick the system into running with a warmer operating temperature. The problem is you don't really know the temperature it is set at (using the dial) so your fermentation temperatures would be hard to set. I found it easier to just do the normal external thermostat ebay controller tied into the 110V input to control the fridge. There are quite a few threads explaining how to do this on the forums, but if you have any questions let me know. (I flush mounted the ebay controller to the fridge itself)

I tricked the fridge into thinking it always needed to be running by removing the NTC wire and replacing it with a fixed resistor. I then ran the NTC wire into my ebay temp controller as the temperature. The fridge has been purring away at 65F since..

So with this setup does the fridge run all the time or does it actually cycle on and off (fans and all)? This is exactly what I would like to do! I will read up on some of the build threads. having your picture will help me out a lot, thanks!

 

[ahave]

I use an external thermostat (eBay aquarium controller) to turn the whole fridge on and off (fans and all).

 

[physast]

Whcih temp control did you buy? THere seems to be three that are available.

http://cgi.ebay.com/ws/eBayISAPI.dl...68&item=150606638066&ssPageName=STRK:MEWNX:IT

and

http://cgi.ebay.com/110V-Temperatur...0&clk_rvr_id=250709145523&hash=item1c1bd59bac

and

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=270629998461&ssPageName=STRK:MEWNX:IT

It looks like one is a dual stage