Adding Fans to improve RV Fridge Efficiency

[Bcborn]

Hello All,

I was on Beech Lanes Web site earlier and I noticed they also manufacture fridge fans.

That got me thinking, last year I saw and article where people put computer type fans in the fridge exhaust vent on the roof. I have seen where people put fans behind the vent cover on the outside wall.

Has anyone here done anything to improve efficiency and was it worth the effort?

[Morich]

I have not done it inSeveral years but we first had RV which were far less "advanced " than what we now use and fans were one way to increase the firg power and cooling.
the reason we used computer fans was because I had them on hand!
But when I look at RV specific fans, they are pretty much the same thing, so if you are DIY trained, a junk computer may be the way to go.
I can find them free at almost any time locally and if I want a specific size, etc. I can always pick them up at local shops for under $5. That means I use them for lots of things like fish aquarium coolers and hobby stuff that don't warrant much thought nor expense. Those that use 12VDC are a natural for RV use?

But one of the best things to do first is to assure that there is nothing blocking air flow from bottom to top around the parts on the back of the frig. There are times when insulation, shields, etc come loose and fall down to block things. Cleaning can be a help if there is a lot of dirt and dust back there.

[Raxel7851]

We bought an RV fridge fan from Amazon and I apologize in advance for not having the link for it. However I believe it works great in our absorption fridge in our MW22M. It runs on 3 lithium batteries, which come with the unit along with a charger. It has 3 settings and on the middle setting it usually runs for 3 days. I put it on the bottom shelf making sure there’s nothing obstructing the airflow on the shelves above it. I do believe it helps especially in warmer weather.

[bigb]

I made a ton of mods to my absorption fridge, condenser fans, insulation, improved convection venting and improved hot gas venting (original installers vented the flue in the compartment instead of outside), new propane regulator adjusted for 11" of WC with 1/2 of my appliances running, every mod helped but the biggest single improvement was evaporator fans https://www.amazon.com/Triple-Deluxe.../dp/B072BPYXS8 which made it possible for the first time to set the fridge on #4 instead of maxed out on #5 all the time. You can hook them up to a switch but I bought a Fridge Defend with fan controller and it runs the fans automatically as needed.

If you have side vents instead of a roof vent then condenser fans can help but make sure your back wall clearance is under 1" and there is not a square trap at the top that prevents the free convection of air. I used 8" PC fans with a very low CFM, if you get too aggressive it will disturb the natural convection, you just want to "encourage" convection, not confuse the natural flow. I also used some aluminum dryer ducting and opened it up to make a gentle curve at the top vent instead of the square box that traps heat.

One of the worst installation mistakes I see with absorption fridges is too much space behind them which results in the convected air bypassing the condenser coils. You can build baffles but I pulled the fridge and fastened some foil backed foam insulation board to the wall bringing my rear clearance to 3/4" and also adding thermal insulation when parked with the sun on that side.

I think a lot of people dislike absorption fridges because they had bad experiences with them but with a bit of work and know how you can make your absorption fridge perform very well on very little propane and practically no battery usage.

[Bcborn]

Here is the Beech Lane Evap Fan from their site.

https://www.amazon.com/dp/B0B7SF3YFB?ref=myi_title_dp

[bigb]

That should work fine. I paid more because I liked the thin size and the commercial looking steel but that one should work just as well.

[Gunny Rio]

I added the Beech Lane to our 1708FB

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Made a huge difference. Even tho this unit's fridge is vented to the roof it wasn't sufficient enough. In hot weather, or when the sun was on that side, the fridge wouldn't stay cold. I added this and the issue was gone. One of the best mods I had installed yet.

[bigb]

Originally Posted by Gunny Rio

I added the Beech Lane to our 1708FB

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Made a huge difference. Even tho this unit's fridge is vented to the roof it wasn't sufficient enough. In hot weather, or when the sun was on that side, the fridge wouldn't stay cold. I added this and the issue was gone. One of the best mods I had installed yet.

Gunny, did you put those behind the fridge or inside on the evaporator coil? I think the OP is referring to fans on the evaporator coil but if you used those vent fans on your condenser where did you locate them, on the bottom vent drawing air in?

[Gunny Rio]

Yes, mounted these to the air intake vent not on the coils themselves. Mine is always set to suck air in then force out the roof chimney.

[Bcborn]

Originally Posted by bigb

Gunny, did you put those behind the fridge or inside on the evaporator coil? I think the OP is referring to fans on the evaporator coil but if you used those vent fans on your condenser where did you locate them, on the bottom vent drawing air in?

I was referring to all options and wondered which is best;

1) On Evaporator Coil inside of fridge - pulling cold air off coil and blowing around inside fridge

2) On shelf inside fridge circulating cold air within

3) On Exhaust Vent - Roof or Upper wall - pulling fresh air through the system

4) On Intake Vent -Side Wall pushing fresh air through the system

Gunny was their a reason for choosing option 4 over option 3

[Sprockets]

Here’s a good video on the subject. https://youtu.be/eCBU_RGsywM

[AlanO]

I just finished installing both evaporator and condenser fans in my refrigerator.
Wired the condenser fans to the existing fan circuit and added a 40C thermocouple and blocked the unused part of the chimney around the condenser with foil backed foam board.
The evaporator fans just clip to the fins and the wires are run through the drain tube to the 12V LC circuit.
The evaporator fan comes with a 2 speed switch on the face that I turn on when starting the refrigerator.
Efficiency has gone way up and interior temperature stays below 38F and freezer close to zero.
Total cost $47.00, well worth it.

[peggwn]

Originally Posted by Bcborn

I was referring to all options and wondered which is best;

1) On Evaporator Coil inside of fridge - pulling cold air off coil and blowing around inside fridge

2) On shelf inside fridge circulating cold air within

3) On Exhaust Vent - Roof or Upper wall - pulling fresh air through the system

4) On Intake Vent -Side Wall pushing fresh air through the system

Gunny was their a reason for choosing option 4 over option 3

Referencing Post #10 -- 2-3 years ago I used computer fans and implemented options 3 & 4. The fans could be linked/chained so I put 2 at the top atteached to the exhaust vent grill to draw out the warm air and 1 at the bottom mounted near the intake grill to pull in cooler air. I tapped a 12v line for power. I started the "chain" at the bottom, so I could put an ON/OFF switch there for easy access.

Before we fire up the fridge for a trip I take off the intake grill and flip on the switch. The fans are nearly silent when operating. This has vastly improved the fridge section of the unit, which now holds the temp in the mid-30s, and lowers the freezer section some as well (from high 20s to the low 20s, even to mid teens). I turn it off when we get home.

Hope this helps. George

[Bobn1957]

Originally Posted by Bcborn

I was referring to all options and wondered which is best;

1) On Evaporator Coil inside of fridge - pulling cold air off coil and blowing around inside fridge

2) On shelf inside fridge circulating cold air within

3) On Exhaust Vent - Roof or Upper wall - pulling fresh air through the system

4) On Intake Vent -Side Wall pushing fresh air through the system

Gunny was their a reason for choosing option 4 over option 3

I installed the ARP Fridge Defend system after reading about fires caused by the absorption fridge overheating. The Fridge Defend also has built-in controllers for external condenser fans (they recommend installation at the bottom of the plenum) and internal fans to blow air onto the evaporator fins! All in all it seems to be very effective as the freezer and fridge sections keep things cold even in hot weather!

[RovingMedics]

Originally Posted by Gunny Rio

I added the Beech Lane to our 1708FB

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Made a huge difference. Even tho this unit's fridge is vented to the roof it wasn't sufficient enough. In hot weather, or when the sun was on that side, the fridge wouldn't stay cold. I added this and the issue was gone. One of the best mods I had installed yet.

I am curious about this. We have a 2108FBS (FLX) with the Domestic fridge but I'm not seeing where I'd have room to add such a fan. Did you have to cut into the exterior?

Do you have any photos of your install that you could share?

[Bobn1957]

Originally Posted by RovingMedics

I am curious about this. We have a 2108FBS (FLX) with the Domestic fridge but I'm not seeing where I'd have room to add such a fan. Did you have to cut into the exterior?

Do you have any photos of your install that you could share?

I mounted my fans onto the inner face of the lower cover to push air up the plenum through the coils, you could as some have done put them at the top to pull the air through the coils but my thinking is the heat would shorten the life of said fans! The fans are just computer cooling fans about four inches square and one inch deep!

[Fred 2106DS]

Originally Posted by Bcborn

I was referring to all options and wondered which is best;

1) On Evaporator Coil inside of fridge - pulling cold air off coil and blowing around inside fridge

2) On shelf inside fridge circulating cold air within

3) On Exhaust Vent - Roof or Upper wall - pulling fresh air through the system

4) On Intake Vent -Side Wall pushing fresh air through the system

Hi Lyle,

I installed both an evaporator coil fan using a computer fan I had laying around and the ARP Fridge Defend system with intake vent fan on our MM. This combination has been working well for us.

Here are write ups on both installs.
evaporator coil fan - I did make one change after this write up, I connected the negative fan wire to the negative for the refrigerator light instead for the the evaporator fin. Using the fin as a ground is not recommended according to the ARP website.
ARP Fridge Defend system with intake vent fan

Fred

[Bobn1957]

Originally Posted by Raxel7851

We bought an RV fridge fan from Amazon and I apologize in advance for not having the link for it. However I believe it works great in our absorption fridge in our MW22M. It runs on 3 lithium batteries, which come with the unit along with a charger. It has 3 settings and on the middle setting it usually runs for 3 days. I put it on the bottom shelf making sure there’s nothing obstructing the airflow on the shelves above it. I do believe it helps especially in warmer weather.

According ARP the theory is that if you aim the interior fans at the cooling fins they will blow the warm air that rises up the space between the door and the shelves the resulting cold air will fall down the back of the fridge. Sound about right to me and that is what I did.

[Bobn1957]

These are the fans I installed at the top of my fridge and pointed at the cooling fins! I used VHB double-sided tape to mount them. https://www.amazon.ca/gp/product/B01...?ie=UTF8&psc=1

[Bcborn]

Originally Posted by Bobn1957

These are the fans I installed at the top of my fridge and pointed at the cooling fins! I used VHB double-sided tape to mount them. https://www.amazon.ca/gp/product/B01...?ie=UTF8&psc=1

Did you mount them on the side walls or ceiling, wire them together then one set of leads down to the light?

Do you have pictures of your mounting?

Thanks