Report on use of Internal fridge fan and venting

i have my fridge vented inside and have no probs at all .I like the idea of the internal fan.Have you got it so it switches on and off with the compresser? Thanks

Bushtrackers Position on this... (And I would rather our R&D stay on the Owners Forum) But here you go, a repeat of TIP # 99. We are not here to argue the point, just to tell of our experience over the ten years and why it is not standard for us.... And why it is not in our own vans... AM I BEING FAIR DINKUM? Well, I just reviewed this with Tracy (the other Director) to see if our position has changed any in the year since TIP # 99 was out... And it has not... SO IS IT ABOUT DOLLARS? No, it would be CHEAPER FOR US TO INTERNALLY VENT THEM ALL AS A STANDARD..! So what then? Here is our view on the matter:

TIP # 99 Internal or External Venting on the Fridges

Hello Boggers in planning! There is a good argument about the advantages of interior venting for the fridge instead of the external venting as we normally do. Here are the summary of good points and bad points for internal venting:

Good points:
1) The idea is that the internal venting allows better heat exchange with the condenser coils on the back of the fridge. In normal running conditions this may be true, as you can get a higher volume of convection air flow.
2) Another argument is that it eliminates the bull dust entry into the condenser and compressor area.

Bad points:
1) Refrigeration is not about making cold, it is a process of removing heat… The idea of better heat removal goes to pieces, when the van is locked up, and the internal temperatures in the van can soar to 50 degrees or more. Then, when the van is locked up while you are on a Tour somewhere, in town shopping, off fishing or exploring, the fridge is struggling against the heat of the locked up interior generated by the sun. Even on trips when you are driving, the van is all locked up in the bull dust or desert crossings; ever feel that warm blast in the face when you open the van door? The fridge is struggling to cool itself in those conditions… You are making an artificial 50 or 55 degree heat wave the fridge has to work against. Refrigeration is not about making cold, it is a process of removing heat…
2) Bull Dust? On 10,000 kms across the Red Centre, we pulled the vents and looked inside expecting to find a lot of dust… Maybe we found ½ to 1mm to vacuum out? It seems that whatever blows in, blows back out and most does not settle in the fridge compartment.
3) Maintenance and repairs or just checking something out? A lot can be done to check things out, through the external vent at the bottom of the fridge, instead of having to pull the fridge out….

The short answer and our analysis?
Well, if you were going to summer over in Arnhem Land, living on 240v power with air conditioning on, then yes the internal venting makes sense. The load on the fridge would be alleviated with the cool air supplied by the air conditioning. Then it definitely works better and lessens the loading on the fridge itself as the air conditioning dissipates the heat. Also, that far north in summer and the fridge would struggle anyway, and might not shut off at all during the day. The air conditioning would be working in favour of the fridge.

The problem is that most people are not going to summer over in the far north. In normal conditions, with the van locked up in heat during the day when you are out, it might just burn more power as the interior of the van heats up working against the efficiency of the fridge. The fridge will produce heat on its own, but the raising of the internal temperature is negligible compared with the heating up of the van in the sun with all windows and such closed as in travel or sitting somewhere closed up for security reasons while you are away. Then the interior temperatures can soar, and the fridge will struggle, using more power. I would say that internal venting is an Option, and we will do it, no charge, but it should be restricted to the far North and living on AC. Otherwise it is another idea that could be counterproductive for majority… However, you may chose to disagree, and we will now do it as an option F.O.C….. But not in my van.

While we listen to all ideas, we test them in time, and the “proof is in the pudding.” I think we will stick to the external venting and access to the back of the fridge as our Standard, with internal venting upon request.

Regards from the Ranger.

I believe that both Turist Bob and I have used our vans for extended periods in both hot and dusty conditions as described above by Bushtracker, with and without external vents. As such we are both in a position to be able to compare fridge operation with and without external vents.

I believe Bob did a test once with his internally vented van and Tracy's externally vented van and found the internal venting to have a lower temperature behind the fridge than the externally vented one.

My finding was a far greater amount of dust in the rear of the fridge than described above, and I believe the fridge works more efficiently with internal venting than with external venting. I must have a better insulated van as I haven't noticed the van temp inside being hotter than outside. When we are parked we always have the 4 season hatch open, and when travelling on sealed roads the rear shutter of the 4 seasons hatch is open, so our van is only ever sealed up on dusty roads.

It is good to see that people can now opt to have the fridge vented internally if they wish to do so. At least everyone ordering a new van now can make an informed decision on which way they wish to go.

Brian

We have had an item to improve the fridge cooling, mainly to reduce how often it runs on hot days, on our list for a couple of years. Initially we were going to try to force more air past the evaporator and/or improve insulation.
I was going to try to find some of my old uni books on thermodynamic and consider building a passive device to increase the air flow by causing a suction on the top vent.

As our fridge cupboard is the height of the fridge, we can't lift it for feet without lifting the shelf above the fridge, so I was wondering how much improvement is in the internal fan and how much is in the internal venting i.e. how would I go with the fan and leave it as external venting.

I can see one difference with the external venting that is not mentioned. Looking at the arrangement and positioning of the upper external vent, one advantage of internal venting is that if forces air up past a larger area of the condensor. Also I suspect it 'draws' better than the external vent i.e. improves flow velocity.
I have always considered my problem is that I have hotter air outside the van than behine the fridge and no real difference between the upper and lower vent.

Brian,
We have noticed our fridge struggles to stay cool on the top shelf (remote thermometer). The internal fan sounds great. Any chance of a photo or at least a description of how you got power into the fridge neatly?? Any reason why you couldn't use the power at the internal light if you wanted it on all the time??

Thanks
Matt