Improving 12V Fridge Performance in a Teardrop Trailer

[Yoshi1]

Hi,

You can see from my profile picture I have a 18' teardrop. Everything works very well except for the fridge when the cabin gets warm and performance degrades. I know many RV fridges suffer from this issue. The two things I keep reading to help improve performance is an exterior fan in the rear to help dissipate heat and also a small internal fan (in addition to shade). I just completed the exterior fan install and I'm wondering (as long as I have the fridge out) if adding any insulation to interior surface of the walls of the two exterior walls would provide any benefit.

When in the sun, the back and right exterior walls can feel get quite warm.

Has anyone added insulation and saw a benefit?

There is only 1/4 " of extra space between the width of the cubby and fridge...so it would be a thin section of insulation on the right side . The back has much more space for insulation.

Any other suggestions that you have found to improve performance.

What compounds the problem, is the fridge (Isotherm Freeline Slim140) has no inside evaporator fan to push air around. It just counts on cold air dropping to cool. And it's a tall fridge. The freezer works great. It's a straight 12V fridge

Thank you

 

[Domo]

Yup, park in shade, give air help getting up and over it's top (and out to the room most likely). MFG requires 10 CM of vent space at the to, which I would think might be pinched at the back by the slope of the RV's ceiling.

MFG stresses air flow as shown - any way to increase heat exchange would be a help.

With no interior fan (a computer muffin fan WOULD BE a great addition) mounted inside - and do not overpack as you need air to circulate as you have mentioned.

 

[DonTom]

I just completed the exterior fan install and I'm wondering (as long as I have the fridge out) if adding any insulation to interior surface of the walls of the two exterior walls would provide any benefit.

In my Y2K fridge, I added a Fridge Defend with a fan on its small Dometic and it is more stable in temps. But still not quite as stable as my four door Norcold in my 2022 Class A, but well within reason.

-Don- Verdi, NV

 

[Kirk]

From looking at the last picture, it seems the refrigerator is just inside of the walk-in door and facing forward. The storage above the fridge means that the exit for the warm air must be through an opening in the sloping rear section. The ideal for absorption refrigerators is to have a vertical vent through the roof but since that isn't the case, you should see significant improvement with the addition of fans to move more air. I also agree with Don that the Fridge Defend would be a good addition, the fans you are adding should help a lot. I doubt that the small space beside the fridge would allow enough insulation to make a significant improvement.

 

[Yoshi1]

tks for the feedback. The fridge is only 12V, not an absorption style so that device would not work (I think)

 

[Gary RV_Wizard]

tks for the feedback. The fridge is only 12V, not an absorption style so that device would not work (I think)

That's correct - Fridge Defend is intended for use with absorption fridges.

The only addition you will have room for will be a reflective barrier, aka radiant insulation. Reflectix or similar. Probably not going to help a lot, but it's inexpensive and can't hurt.

The exterior fan you are adding should help quite a bit. There isn't a lot of space for convection air flow (see post #2), so the fan is a plus. Keep it clean underneath so that "dust bunnies" don't further impede air flow.

An interior fan won't make it colder, but will even out the temperature inside by circulation the chilled air. It doesn't need much to stir things up inside, so a small fan made for electronics cooling should be fine.

 

[8Muddypaws]

Nice work!

Compressor refrigerators are not as sensitive to air flow as evaporative units but you do need some. In your case the airflow can’t be very good though.

I installed a compressor driven 12V cooling unit (from JC Refrigeration). It works very well even on hot days with the sun hitting that side of the rig. It has fans right on the coils and also on the fins in the refrigerator box. But because it has two exterior vents, one low and one high, it probably gets better airflow. It’s a fairly large 4 door Norcold 1201

Switching to external airflow might be an option but you’d then be cutting holes in the side of your trailer and covering the existing internal paths. I’m sure the parts to do it wouldn’t be hard to find.

 

[John From Detroit]

Something hit me in the memory system.

Is this a tall fridge/freezer or just a small say 2-4 CF. like a colean cooler possibly with a front door.

There are two types of the lat ter.. Or 3 You eliminated one however (Absorption)

The two types are Compressor like my little freezer, I can turn it to "Fridge" if I choose (Adjustable)
And another that's "Solid state" the only moving part is the fan and the temp-switch.

These use Peltier effect Devices which ...well the ones I've used were good for about -30 degrees as recall. that is 30 below room temp. So if the cabin warms. so does the interior.

 

[Kirk]

The fridge is only 12V, not an absorption style so that device would not work (I think)

Not only would the Fridge Defend not work for you, but it also isn't needed. Ventilation could still be a problem. Are there openings at the bottom for air into and at the top for air exit to get good ventilation? While it isn't as critical for a compressor unit as for the absorption, it still generates heat in the rear which needs to be dissipated somewhere.

 

[Yoshi1]

Hi, Thank you to everyone for the feedback.

Attached are front and rear photos of the fridge. The issue at hand is the cold air made in the freezer has a tough time getting down to the lower heights in the fridge. The issue is compounded when the cabin gets warm.

I'm taking a 3 prong approach:

1. Installed a much larger 2 fan system in the rear to dissipate heat. The OEM fan was a single small computer type fan. The fan you see in the picture moves much more air. The outside vents at the bottom and top of the fridge are fully unblocked. Hopefully this will create a chimney effect to move hot air from the rear.

2. I installed a 12V fan for the fridge inside. The fridge has no evaporator fan and the cold air produced in the freezer is moved down simply by convection. The inside fan will hopefully push warm air up and mix it better with the cold air at the top.

3. This is a wild concept on my part, but in the freezer, I installed the computer fan in the rear of the freezer section. The freezer section is where the cold air is produced but solely relies on convection to get it down into the fridge via a small opening in the rear of the freezer. Maybe the fan inside the freezer section will move more cold air down. This is how a home fridge works. This fridge has no internal fan to move air.

The freezer fan is sitting on something (see picture) I made so the rear of the freezer compartment is not blocked (by food) to allow the cold air to work its way down.

I realize none of this produces colder air just trying to move the cold air produced and dissipate in the rear.

We'll see how it all works...

 

[John From Detroit]

Ok that is a compressor model (you can see the compressor in the rear shot)
Those coils on the back are like the Radiator on your Car's engine. if there is no air flow around them it overheats. so keep them do not block air flow around them. Adding a fan to blow air UP behind the Fridge.. Likely won't hurt, may help but of course fans make noise.

 

[RayIN]

Ok that is a compressor model (you can see the compressor in the rear shot)
Those coils on the back are like the Radiator on your Car's engine. if there is no air flow around them it overheats. so keep them do not block air flow around them. Adding a fan to blow air UP behind the Fridge.. Likely won't hurt, may help but of course fans make noise.

Look again, Freeline Slim 140 - IndelB

 

[John From Detroit]

Look again, Freeline Slim 140 - IndelB

I did per the spec sheet
Compressor BD80CN

It is a compressor type.

 

[Yoshi1]

Hi,

For any interested folks...

Ran an experiment. Here is the fridge data for four days. Seems to indicate the fans really help. With 4 days of about 100F inside the camper, it maintained pretty well. (kept is closed to heat it up)

Of course, this was with no opening of the fridge door in between measuring temps.

It's supposed to be cool the next few days but low 90s later in the week. Then I'm going to load up the fridge (with food), open and close the door a few times and see how well it responds. As you would guess, when you open the door just for a short bit, the warm air rushes in and warms up the interior quite quickly. Want to see how quickly it pulls back down.

Once cold, any items in the fridge should act as a thermal mass and help keep the fridge cool when opening and closing the door (I'm guessing).

I think if the interior fan was placed in the bottom drawer, it would have cooled better, but then again the bottom drawer is blocked by the top drawer.