How to rig up a fan for my keezer?

[DuncB]

Imagine a world with nothing but warm beer.

It's called cellar temperature.

 

[Nagorg]

One could get a rough idea by looking at the "back panel" ratings on the fan.

~4.8W for this one, provided run at the full 24V

I just did a semi-scientific experiment. I read the temp of my AC fan while "cold" at room temperature when it had been off for days. Then I powered it on and let it run for ~15 minutes and read the temp again.

I determined a ~7-8 degree Fahrenheit temp increase which seemed surprisingly high to me. I then did the same thing with the PC fan that I've been using from my old keezer. This thing showed a ~4-5 degree Fahrenheit temp increase. So less heat for sure but still a heat source.

My AC fan speed controller came in today and it does result in noticeably reduced noise. I'm assuming there will be reduced heat output as well, likely closer to the PC fan I'd guess. Maybe I'll measure it too. Or maybe I'll just RDWHAHB!

 

[Clint Yeastwood]

It's called cellar temperature.

So where I live, about 87 degrees. Maybe I should invest in sake.

 

[JohnDBrewer]

I run a fan in my keezer but really only to defrost, get rid of the ice build up at the bottom. Also, if I know I have folks coming over, I'll turn it on the day before so to even out the temp. I notice with floating dip tubes I have to run my kreezer about 5 degrees lower since I'm pulling off the tops of the kegs, and no longer pulling from the coldest part of the keg.

This is my second keezer. The first lasted about 7yrs, 13cubic ft. Was probably 10yrs old when I bought it for $50. The current one is 10-11cft and is dated 2010. Cost me $150 in the middle of the pandemic and was happy to get it at that price. I can't see buying a new one when used ones are so much cheaper.

I use pipe insulation around the shanks. Not sure it makes any difference, but I had it sitting around. I built a cover out of Styrofoam to cover the taps years ago on the outside, as my keezer sits in the garage, but I found the inside of the taps would grow mold, even with faucet plugs, spaying with sanitizer, etc., so I trashed that idea.

 

[beren]

More great news: R134a is being phased out because of the ozone layer. It's already banned in cars. Wonder what they'll replace it with. Wasn't ozone the big issue with good old freon? I guess R134a makes smaller holes or something.

r134a is long gone in freezers and fridges. They all went back to using different types of hydrocarbons, just like the original ones do. Only downside is that it's basically LP and is flammable if it leaks out. Works great however!

 

[Nagorg]

it's basically LP and is flammable if it leaks out. Works great however!

Cyclopentane?

 

[whoaru99]

Maybe I'll measure it too.

Sure, you can, but unless cooling capability is quite limited I'll opine it's not going to change much.

While a higher temp rise may be indicative, I suggest the net BTU working against cooling in either case is pretty small in the big picture.

 

[Clint Yeastwood]

Cyclopentane?

I remember seeing that word on one of my freezers, on a label I tore off in contempt without reading it.

So I guess I have cyclopentane. How long before they take that away from us? There has to be something wrong with it.

I see an appliance repair blog discussing R134a, the evil, disgusting, backward gas everyone now hates. A 2022 post says the cost of 30 pounds of R134a had gone from $130 to over $500. Get ready to throw out your expensive fridges, which were probably impossible to repair anyway.

 

[Nagorg]

Sure, you can, but unless cooling capability is quite limited I'll opine it's not going to change much.

While a higher temp rise may be indicative, I suggest the net BTU working against cooling in either case is pretty small in the big picture.

Agreed... That's why I said:

 

[Nagorg]

I remember seeing that word on one of my freezers, on a label I tore off in contempt without reading it.

I've not been able to find anything definitive saying that cyclopentane is the actual refrigerant. I ASSume it is though based on the big sticker. But most of the references I can find about cyclopentane suggest its used more in the foam insulation process, not as a refrigerant.

But until I can find a more definitive reference one way or the other, I'll continue to ASSume its the refrigerant.

 

[day_trippr]

Yes, Cyclopentane is a more environmentally friendly (though highly flammable) foaming gas. When my current freezer arrived there was a big yellow sticker on the compressor end of the unit screaming CYCLOPENTANE - which immediately made me think it was the refrigerant. But, no, it's what's used to inject the insulating foam inside the cabinet and lid...

Cheers!

 

[Clint Yeastwood]

So they're using a refrigerant gas to pump up foam, but something else in the compressor? I guess that shouldn't be a surprise.

 

[Nagorg]

So they're using a refrigerant gas to pump up foam, but something else in the compressor?

This remains a mystery to me...

 

[day_trippr]

This is the sticker on my 2020 14.3cf chest freezer.
Contrary to the supposition that r134a is history, that is what flows inside this freezer...

Cheers!

 

[jerrylotto]

Here is what I did. It runs full time when the controller has power. Just a computer fan taped to a duct elbow, so it pulls cold air from the bottom of the freezer and blows it up. The orange thing is an oil pan heater that the fan blows over when the controller is heating the chamber. I should probably put a screen over the open end, but I haven't had a problem yet.

 

[Broken Crow]

Here is what I did. It runs full time when the controller has power. Just a computer fan taped to a duct elbow, so it pulls cold air from the bottom of the freezer and blows it up. The orange thing is an oil pan heater that the fan blows over when the controller is heating the chamber. I should probably put a screen over the open end, but I haven't had a problem yet.

View attachment 839165

Top marks from me! That's exactly the kind of jury-rigging I love to see. You're the perfect one to ask this of; I know that some folk put their temp probe in a bottle or cigar tube... Have you tried this and does it make much difference to compressor cycle times? Just thinking it would be nice for someone on here to do that comparison as cycle-times seem to be the number one killer of units. I've also wondered if there's much difference between bottom>top or top>bottom circulation.


PS: I'm a fan of R-600, Isobutane, highly efficient and yeah it's flammable but I don't do anything that may compromise the unit, so I'm not worried about leaks.

 

[jerrylotto]

Note that there's a quick disconnect on the temperature probe. I have NTC 10K probes permanently mounted in all of my fermentors, I just plug them in when I have them in the keezer so the temperature control is on liquid temperature.

 

[Broken Crow]

Note that there's a quick disconnect on the temperature probe. I have NTC 10K probes permanently mounted in all of my fermentors, I just plug them in when I have them in the keezer so the temperature control is on liquid temperature.

Do you get any notable differences in compressor cycle times between the probe as pictured to when it's plugged into a fermenter-probe?

 

[jerrylotto]

Do you get any notable differences in compressor cycle times between the probe as pictured to when it's plugged into a fermenter-probe?

Never really paid much attention to cycle times. It just maintains a more stable liquid temperature.

 

[whoaru99]

Do you get any notable differences in compressor cycle times between the probe as pictured to when it's plugged into a fermenter-probe?

Years back I posted some traces of temperatures I recorded with some datalogging equipment. Unfortunately those images seem to be gone and I can't find the originals.

As I recall, the cycle times did vary between air temp and immersion or insulated surface temp. But, as one might guess, the liquid temp didn't swing much at all because of the relatively large mass.

Maybe I'll record all that again one day, if for no other reason than just because.

 

[jerrylotto]

Years back I posted some traces of temperatures I recorded with some datalogging equipment. Unfortunately those images seem to be gone and I can't find the originals.

As I recall, the cycle times did vary between air temp and immersion or insulated surface temp. But, as one might guess, the liquid temp didn't swing much at all because of the relatively large mass.

Maybe I'll record all that again one day, if for no other reason than just because.

You do have to set the controller to lower tolerances when you're controlling by liquid temperature reading. I use a 2° spread for liquid in a 3° spread for air/ambient.

 

[whoaru99]

I can buy into a smaller window for controlling by liquid temp.

I went out to 5 degrees, but I don't recall if it was +/-5 or +/-2.5 when doing air temp to try to reduce compressor cycles and the liquid temp was still quite stable as I recall.

 

[beren]

I like to tape/tie/rubberband the temp probe to the lower part of a keg, maybe with a little foam over it.

 

[DuncB]

I like to tape/tie/rubberband the temp probe to the lower part of a keg, maybe with a little foam over it.

A blob of blu tack and then the microfoam pad held on with a bungee cord seems to work well on my fermenters.

 

[shavy]

I like to tape/tie/rubberband the temp probe to the lower part of a keg, maybe with a little foam over it.

Yep, it’s what I do in my keezer.

 

[day_trippr]

Two things are important: good coupling between probe and vessel wall, and good isolation from the chamber temperature. I use a 4"x6" inch-thick closed cell foam pad over the probe, and pin everything firmly in place with a 2" wide velcro strap. I use the same technique for monitoring my carboy fermentors and corny kegs.

Also, somewhere in the catacombs of HBT there is a post of mine showing temperature plots with my keezer compressor state similar to the one below taken just now...

... showing what happened when the controlling sensor was strapped to a keg, strapped to a 12 oz bottle of water, and hanging in the middle of the keezer, with the cycle times going from the 6~7 hours shown here, to around an hour, and then to roughly 30 minutes...

Cheers!