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GordonThree's avatar
GordonThree
Explorer
Aug 06, 2018

Overkill Fridge Fan

A while back in another thread I mentioned buying two 3000 RPM 24 volt industrial fans for using to power vent my fridge on very hot days, to help improve efficiency.

I finally got around to installing them. I went with two Noctua iPPC 24v 3000RPM units, IP67 rated. They support pwm speed control but I'm currently not using that feature.



The fans are installed using silicone pegs? on a piece of aluminum angle stock. I re-used two mounting screws that hold the factory air damper in place.

The fans connect to a piece of 18ga cable which runs down to the bottom of the vent, where it's connected to a 12-24v boost converter and remote switch that is tapped into the fridge 12v supply.



I became overwhelmed by mosquito as I was installing the remote switch and didn't grab a picture. I'll try again shortly. The remote switch toggles on when ambient is above 85F and off at 82F, probably lower than it needs to be but 90-100 degree days are very rare in these parts.
  • garyemunson's avatar
    garyemunson
    Explorer II
    Nov 19, 2018
    What I did....

    https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/29770712.cfm
  • CincyGus's avatar
    CincyGus
    Explorer II
    Nov 17, 2018
    Fans

    I've got one of these in a old PC on the top of the case to exhaust heat. It's quiet, effective and a great fit for this project. I've done this mod on both my previous popup and Travel trailer and it eliminated any worry about the frig keeping up on 100 degree days.

    I have it stated on my Spring to do list on the new Toy Hauler.
  • wopachop's avatar
    wopachop
    Explorer
    Aug 14, 2018
    GordonThree wrote:
    Yes, I can hear them from inside. Not concerned about the noise or power usage.

    Rpm is not the lone determining factor for the performance of a fan. Wattage, static pressure and air mass movement are important variables to consider. Bearing type, motor design and price are also a consideration.

    For all who feel that better 12v fans exist, please share the link. The fans I chose where not selected at random or by mistake, nor were they selected to be silent.

    My fridge has no roof vent. It is a small unit and uses two side vents. The fans are installed in the upper exhaust vent and fit flush with the vent cover when it is installed. No additional baffling is required nor desired from the analysis and testing I have preformed.


    I dig the setup for sure. Do you have a picture of your temp switch? I bought 4 off ebay, all 4 arrived broken. Seller never sent replacements.

    For the sake of fun fan topics the 12v version getting 13.5 or 14.4v will probably push more air than the 24v fan on a boost. Assuming its a set voltage and not adjustable. Noctua had them listed with identical specs.

    I too need to overkill my fridge. Bought a small 80mm Noctua but i dont think its enough when running on electric and its 110F outside.
  • grandpopsicle's avatar
    grandpopsicle
    Explorer
    Aug 14, 2018
    GordonThree wrote:
    A while back in another thread I mentioned buying two 3000 RPM 24 volt industrial fans for using to power vent my fridge on very hot days, to help improve efficiency.

    I finally got around to installing them. I went with two Noctua iPPC 24v 3000RPM units, IP67 rated. They support pwm speed control but I'm currently not using that feature.



    The fans are installed using silicone pegs? on a piece of aluminum angle stock. I re-used two mounting screws that hold the factory air damper in place.

    The fans connect to a piece of 18ga cable which runs down to the bottom of the vent, where it's connected to a 12-24v boost converter and remote switch that is tapped into the fridge 12v supply.



    I became overwhelmed by mosquito as I was installing the remote switch and didn't grab a picture. I'll try again shortly. The remote switch toggles on when ambient is above 85F and off at 82F, probably lower than it needs to be but 90-100 degree days are very rare in these parts.



    Nice job. :C Love it. Can't get any better than noctua fans. Super quite!

    Those are on the bottom?
    If so it could be a much better setup. As the heat rises the fans will be fighting to pull air down. If they are on the bottom may I make a suggestion???

    Put one in the bottom pointing up at the fins/coils/condenser and the other in the top vent pulling out. It will be waayyy more effective.
  • GordonThree's avatar
    GordonThree
    Explorer
    Aug 14, 2018
    Yes, I can hear them from inside. Not concerned about the noise or power usage.

    Rpm is not the lone determining factor for the performance of a fan. Wattage, static pressure and air mass movement are important variables to consider. Bearing type, motor design and price are also a consideration.

    For all who feel that better 12v fans exist, please share the link. The fans I chose where not selected at random or by mistake, nor were they selected to be silent.

    My fridge has no roof vent. It is a small unit and uses two side vents. The fans are installed in the upper exhaust vent and fit flush with the vent cover when it is installed. No additional baffling is required nor desired from the analysis and testing I have preformed.
  • wopachop's avatar
    wopachop
    Explorer
    Aug 14, 2018
    I dont think you can beat the computer fans. They do make those 3000k in 12v. Around 20 bucks on amazon. The auto radiator fans are crude and cost a similar price.

    Can you hear the fans from inside? Another option would be the 2000k version. Or buy the PWM controller down the road.
  • toddb's avatar
    toddb
    Explorer
    Aug 09, 2018
    I used two 120mm fans, they move ok air. Combined less power than the single fan and dead silent.



    Shroud to ensure all the air goes were it needs to:


    I have an internal fan as well, I 3d printed a mount for it. I froze my wife's soda at 29*.
  • memtb's avatar
    memtb
    Explorer
    Aug 07, 2018
    We’re in the process of finishing-up a similar set-up! Went with two fans, though less cfm than yours. Our unit has two vents (for better drafting, I presume), a lower and upper. The original fan was located between the two vents, just above the refrigerator coils. I located the new fans in same location. Not an easy access! Our fan (single) failed earlier this summer, and had severely diminished refrigerator performance. Should finish and test the install today!

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