Fan on fridge compressor? If so, where?

[WalkaboutTed]

Good evening, all,
I have our fridge on order. It's a Truckfridge 130 (Indel B/Vitrifrigo). Since we are in the Arizona desert and will be coming back here on a regular basis, even in the heat of summer, I'm trying to figure out how to keep the fridge from having to work more than it already has to.  It's going to be in a well-ventilated, shaded space under the bed and we'll be putting insulation all around it, even a removable panel in front. The compressor area will be placed where I very easily can put a fan.  I have some questions :

#1 should I even use a fan, if so, should I point it towards the compressor? I was thinking of a 12v or USB fan.

#2 if I should use a fan, what would be better, a muffin fan tucked up close? Any particular spot to be aiming at? A regular round fan? Just the general area of the compressor?

I know this is a large fridge, but we've decided we'd rather have fresh veggies, butter and cold drinks (read: beer for the Hubby).  I think we'll have the power, especially if we're willing to give up our Keurig in the morning. 

Thanks in advance,
Ted

 

[John61CT]

Your mission should be getting the heat produced quickly AWAY from the box, and really out of the living space.

The added insulation is great but secondary to that.

Something like the exhaust fan/ducting used in a heater setup would be ideal.

If you don't have A/C running, higher flow volumes will help with cooling, hot dry daytimes pull your intake through damp cloth, helps make the perceived temps lower.

When A/C is running, scale the outflow down.

 

[SternWake]

Can you post a picture of the Cooling unit on the fridge?

The danfoss/secop compressor controller can handle 0.5 amps of 12v fans that come on with the compressor.

The Noctua NF-f12 is 0.05 amps.

The smaller truck fridges tf49 amnd tf65 came with a 92Mm computer fan mounted to a 120MM condenser, sucking air through it.

These fans are better when pushing air through a restriction.

It is pretty simple adding another fan to the compressor controller. I would recommend having it oriented to pull air toward the compressor controller as that is the likely direction the original provided fan blows.

YOu could even upgrade the provided fan to the Noctua or other 120MM fan.

My Vitrifrigo and my extra insulation allow me to mount my Noctua NF-f12 to push air into my condenser, It pulls coolest ambinet air from floor below fridge, and forces all air to flow through condenser then across compressor then compressor controller ( which has heat sink on backside) then either out a louvered vent or into the next section of my cabinet( electrical and storage) where there is another Low CFM 92mm exhaust fan on 24/7.

The TF49's plumbing would not allow this fan orientation pushing into condenser, not sure about the TF130.

So Pics please. Can you see the sticker on the Fan's center hub? See part number and amperage??

The right fan on the condenser can significantly reduce duty cycle, especially when the air it circulates is not air it itself has already preheated.
>>>-Ambeint air-->---120MM Fan--->---->-Condenser->------->Compresssor->--->-compressor controller--->>--OUT

My original 120MM fan pulled .12 amps and attempted to pull 73CFM through condenser
My Noctua 120MM fan pulls 0.05 amps and pushes 53CFM through condenser, Once.

Shorter compressor run times, less amp draw, Less Noise. Win Win Win.

 

[WalkaboutTed]

I've not received it yet, but you can see what they have on the Truckfridge site. It's the same unit as the Vitrifrigo one in my Defender Marine catalogue.

What you guys are saying is kinda Greek to me. I guess when I have the unit in front of me, I can talk in more than generalities.

But the important takeaway is that I will want to put in some type of ventilation system vs installing it with the stock setup.. As far as putting a swamper type unit in, there's no way. We wouldn't be able to carry enough water if we're off the grid. Evaporative cooling takes a huge amount if water. I've paid the water bills when running swampers instead of traditional air conditioning at the house, so I know.

Thanks!

 

[WalkaboutTed]

The editing function here took away part of my last post, but the gist is: I feel somewhat trepidatious about cutting into wiring and modifying or replacing things on a brand new, under warranty fridge . I was hoping that I could just mount a fan on or near the compressor to help out. As far as ducting, we put in a couple of floor vents for stealth camping, so i figured that if we're parked, we'll open those and set the fantastic fan to exhaust heat from below.

 

[John61CT]

That's a great idea, have been struggling with a big fan losing stealth. And now I know to put it right under where the back of the fridge will be!

Almost elegant. . .

 

[John61CT]

Maybe put the recirculate intake for the Webasto heater there too, that will mount right underneath near that spot.

Little preheating boost, every BTU counts when it's freezing out there.

 

[SternWake]

Ok truckfridge's photos of the 130 show a corner mounted cooling unit with a fan inside the condenser, which also wraps around the corner for more surface area.

It 'Might' actually come with a smaller condenser that looks more lika a car radiator's fins, which is the style mine has.

It pulls in air from the back of it and blows it into compressor and this air is then forced to exit from the side, and no doubt a certain portion of this preheated air could get sucked into the fan again.

Ideally this fan would suck only colest possible ambient air, and push it out the side after passing through condenser again.

The Cabinet this fridge is to be mounted into needs to allow for air to get to and exhaust from that upper corner

I asked about the fan as I am interested in figuring out how much cfm they thought was required for this larger fridge. it does appear to be 120MM Which is a big improvement over a 92MM that comes on the 65 and 49.

The existing fan will have two wires going to the compressor controller.

it is very easy to run/ splice the wires to a better fan or Another fan or both.

The compressor controller has simple push on conectors like these:
Well these show the connector, Plus a "piggyback" to add another wire, which would make adding another fan as simple as simple gets:

https://www.amazon.com/Glarks-Insul...9&sr=1-3&keywords=quick+disconnects+piggyback

The cabinet into which this fridge is going, I would add an Exhaust fan to the cabinet Itself, pulling air from the upper side of the fridge. I would use baffles to ensure the fan is not pulling air that did not come go through the condenser's fins. This fan would need there to be n open space behind the fridge with allows cooler air to be pulled into stock fan location then across condenser compresssor compressor controller and into the cabinet exhaust fan.

You could just have passive vents, and it will work 'just fine'. But the Fan(s) pulling air through and out the cooling unit will be many many times betterm using less electricity by shorter compressor run times and cooling down the fridge contents faster.

My cooling unit goes across the back of my whole fridge, making the push pull scenario easier to envision, but your fridge has the cooling unit in the corner to you need to duct cool air for the original fan to suck from and somewhere for the Warmed air to escape to.

Placing the fridge in a cabinet without airflow through condenser will have it perform very badly, consume huge amounts of battery power, and wear out prematurely.

With good cross flow across condenser, the fridge's ability to suck heat out of the box is impressive.

I put an Air filter on my Air intake to keep the fan blades and condenser fins from accumulating dust.



Two Noctua NF-f12 fans likely pull Less electricity than the fan provided with the fridge, and are quieter too.

Note that I say the fridge fan should pull coolest possible Ambient air and push it across condenscer coils.
If your RV is baking in the sun windows closed the fridge will consume HEAPS more electricity, so keeping the interior of RV cooler is wise

 

[SternWake]

In case I was not clear

Products like this make is Simple to add a fan to the fridge without cutting any existing wiring/ voiding any warranty.

This is the backside of the fridge compressor controller:

The thinner red and black wires are for the Existing fan. You would slide these connectors onto the Piggy back terminals above, into which you have already crimped the wires that goto your additional Fan which exhaust this corner of the cabinet. Then you slide ths piggy pack connector on the correct terminal on the compressor controller.

No need to power a full time fan when tapping the compressor controller's fan circuit is this easy.

My full time fan is Inside the fridge (I tapped the 12v for the interior LED light), and the next portion of cabinet which houses my other electrics and needs ventilation anyway. It does asist the fridge fan if I have my foamboard Divider removed.

With Divider in place I open up the sliding conversion can window that is covered by louvered vent, and warmed air gets pushed outside the vehicle.

 

[WalkaboutTed]

Well, aren't those things nifty! If I had known such things existed, I would have saved myself hassle and wire when I did my electrical system. It's nice to know that if I need to , I can eliminate actual splicing. Well, whaddya know!

I looked at the fan, that looks really good. Where we are putting the fridge, serendipitously, the corner where the compressor will be in a big open cavity going into the cabin area. There will be ventilated inches behind it, on the top and a foot of free air on the side. So, what I'm taking away is that instead of blowing air away, I want to assist the compressor fan from behind in bringing in new air, right?

The plan will be, when stationary, to keep the overhead cabin fan exhausting with air coming in from the vents below. What really sucks (no pun intended) is that I can have as much ventilation as possible, but when it's 115F outside, it certainly won't be any cooler inside. When we're in town, we can spend the nights at 7000-8000 feet , but will have to spend time down in the hot valley during the day. That's where the fridge will need a lot of help.

So, when I get the fridge, now I know what to look for and will ask if I need help (which I'm sure will occur).

Next question:. Sternwake, I don't remember where it was, but I saw a photo in one of your posts the air filter that you just spoke of. When I was looking at the photo, even though you explained (I think) about cleaning something with a q-tip, and so on, I didn't understand how you put on the filter, what it's made from and how it does NOT impede airflow. Can you refer me to where I might find more info on that? Of course, now that it's no longer theoretical (since the fridge is now ordered), I went to look for that post of yours and can't find it! But I do remember that it wasn't clear to me.

It's past midnight and I'm turning into a pumpkin, so I'll leave it at that. Thanks for now,
Ted

 

[TMG51]

The TF-130 is the same refrigerator I chose. You can see here how I insulated it within its cabin, and added fans to remove heat more quickly.
https://vanlivingforum.com/Thread-TMG-s-Van-Thread-Picture-heavy?pid=213855#pid213855

Also see SternWake's astute response to my own install; advice which I have not yet followed, but have full confidence in.

 

[SternWake]

So many fridge threads, i do not recall where I posted about the filter.

Basically My fridge rests on a shelf  about 2.5 inches over the floor.

I have a small , backless drawer there with a bunch of holes on the front face.
When the fridge fires up the Noctua fan pulls  in air through these holes.

I use filters made for stick and brick Vents:

I Cut them to the height of the drawer + a Smidge more, and use a diagonal or a U shape to increase surface area, and use blue masking tape to pull them tight

Plenty O flow when compressor kicks on

I made this cover to help direct the Airflow

BTW, this green thing is the inline 270 OHM resistor designed to speed compressor rpm from 2000 to 2500.

I removed it as it does not need the extra cooling power extra rpm allows

I suspect your TF130 will come with some sort of resistor here.

I'd mount a 120MM fan in the cabinet exhausting adjacent to the side of the compressor, allowing Cool air to flow to the back of the fridge from behind and below or from the side opposite the cooling unit if it is to rest on floor.  The goal is to get the condenser in as cool air as possible.

i can do so with the single fan, but with a corner cooling unit, you kind of need another fan to get the similar flow across condenser coils for maximum heat transfer.