Adding Circulation Fan to Refrigerator Box

[Josehoya]

Noctua NF-A12x25 PWM, Premium... https://www.amazon.com/dp/B07C5VG64V?ref=ppx_pop_mob_ap_share

Bought two of these Noctua fans 4 months ago and were an awesome upgrade for the fridge. I bought one and placed it inside on top of the frigo box plate. It’s always on and draws .1 amp. It’s in a corner and sucks cold air up and pushes it easily to the top shelf where thing used to be warm. I run the fridge at a lower setting now and don’t have issues with plate freezing up. The compressor runs less often and I can now turn the fridge to half setting during the night which saves me battery power but everything stays super cold. I don’t have to worry about recharging the batteries in the morning.

I also put one on the fins outside of the fridge that cycles on when the compressor turns on. These were pricey but super effective and the quality just feels top of the line. $30 a pop but I’d do it again in a heartbeat.

[Wainui]

Here is a picture of the Cool Blue fan and pvc tube.
I have a 6 cf freezer and this works well.
https://www.cruiserowaterandpower.co...5-27-2013_.pdf

[FlyingScot]

Definitely recommend Noctua fans. Spend a little more now and less to deal with in the future. I have a big 120mm fan blowing from the top down across one of the evaporator plates. I also installed a small fan sold by SeaFrost. I use zip ties to hold the big fan in place. The little fan came with an overpriced bracket.

I ran a 12v wire that powers on when the breaker is on, into the fridge along the path of the thermostatic bulb then sealed it back up with 4200. I split that using a fan splitter cable.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
My unit is a factory spill over that I have since converted to both sides as a fridge. One 120mm fan blows cold air from the back of one evap plate to the other side. Both sides stay pretty close in temperature with the evap side having a larger swing.
I've considered installing another fan on the non evap plate side, but I keep drinks in the bottom and veggies at the top, so the 3-4F temp difference works out nicely.

I keep both sides between 31-40F as tracked by Sensor Push sensors. I highly recommend these. One of my favorite boat accessory purchases.
https://www.amazon.com/SensorPush-Wi...e-b06387f8bcf1

[Nicholson58]

Originally Posted by sailorboy1

With my recent installation of a separate system for my refrigerator to get rid of my spillover system I have the return of a problem I haven't seen in 8 years. That is stuff in the bottom of the refrigerator box freezing because there is not good circulation in the box. I have one of those battery powered recirc fans in there, but that isn't enough air flow.

So I am going to install a 12V powered fan in there and am interested in hearing stories from those that have done it as to lessons learned.

We also had similar problem but went a long way to fixing by drilling holes in various panels to permit better circulation. Added the battery blower too

[thinwater]

Why not a $12 timer and run it for X minutes every Y hours. All of the fans are too large and the fan wattage, plus increased convection, will increase refer run time. That's what the math says.

[sailorboy1]

The math is wrong if you care about acturally maintaining the correct temp. The real use power readings says the fans reduce power overall AND result in temps being maintained. I can run that 0.1 amp fan pretty much forever on my solar.

[chowdan]

I'd be curious for some numbers in run time before and after!

My refer kicks on for about 12-15mins every 60mins.

Originally Posted by sailorboy1

The math is wrong if you care about acturally maintaining the correct temp. The real use power readings says the fans reduce power overall AND result in temps being maintained. I can run that 0.1 amp fan pretty much forever on my solar.

[Frederic64]

People have been using computer fans, on my Engel I have an extra box on top and using a small computer fan works very well to circulate the air, you can pull one from an old computer and they use very low power.

[JAFO]

Originally Posted by rslifkin

Use a smooth, very sharp jigsaw blade and directly just a tiny bit of water onto the blade to cool it. That avoids the melting / rejoininig problem and the smooth blade prevents chipping / cracking the edges.

In addition to which, use a hacksaw style jigsaw blade, made for cutting metal. The larger number of smaller teeth helps prevent chipping and cracking. Also, run the jigsaw at low speed to reduce heat buildup due to friction.

[smilan]

Originally Posted by sailing_gal

I just finished installing a new refrigeration system. I have holding plates, and I installed the holding plates about 1 inch from the side of the box, and then wired up a computer 12V fan to blow warm air (from near the lid of the box) down along the back of the holding plate, figuring that would give me good air circulation. I am also lining the bottom of the box with the equivalent of Dri-tec tiles. I figure the fans will eventually fail, so I made them easy to get at and replace. They are wired so they come on whenever the compressor comes on and do not run 24/7.

The computer fan is genius. Something like the 92mm Cooler Master TX3 fan draws 0.11 amp at 12V and moves 32cfm. $10, can be mounted in any orientation, and they last for years.

[sailorboy1]

It now occurs to me that I could probably have fixed the issue by just changing the wiring on the evaporator fan inside the refrigerator box to run all the time. I have been having an icing issue with the evaporator so raised the lower temp setting to 37 so maybe it wouldn't ice as much. I also think that running the fan all the time would basically always defrost it as the temp is currently set to 37-39.

[sailorboy1]

Changed the evaporator fan to run all the time and now it doesn't ice up.

[Sailing Drummer]

I did the same thing with the fan - set it up to run all the time. My setup is a spillover system and I was having terrible time with frosting and keeping the refrigerator side at a good temp. I figured that if the fan was running all the time there would be positive pressure as long as the lids were closed. I assumed that would help keep out the moisture. So far it has worked, although I don’t know if it’s because of my theory about the positive pressure or just luck! I set the fan to turn off at 20° F in the refrigerator so it runs all the time. The compressor runs less and at a warmer temp for the freezer plate, but both boxes stay colder. Of course, that all might change by the time I get to S FL!!!!

[sailorboy1]

I battled the frost problem on my spillover system for years. In the end the only thing that works is to separate the boxes and install a system for the frig side. Now instead of thinking the system is working because i had only defrost the freezer every 10 days I only had to do it every 2+ months.

[krid2000]

I'm currently planning to install a circulation fan & hose contraption in my fridge, sucking cold air under the evaporator to the other side & top of the fridge. I'm trying to decide if I should run the fan only when the compressor is running (= 1 new wire to install) or always (2 new wires). My compressor runs about 25-30% of the time.

Does anyone have comparative data between both scenarios regarding energy savings and/or heat distribution? Does always-on make a significant difference?

Thanks
Dirk