DIY: Front Box Fan Install

[robstevens]

After seeing various threads on the ventilation (or lack thereof), in the Tvan's front fridge box, I've decided to try a solution...

The existing box comes with two grilles, each covered by a cotton filter: One on the door, the other in the middle of the rear wall of the box.

I decided to "adjust" the one on the door, as the other one is not easy to get to.

First, removal of the filter:



Next, I made up a new filter holder, with sides, so that I could mount two computer cooling fans in front of it:



I bought some 12v computer cooling fans off Ebay, which only draw 0.2 Amps each. I looked for ones with at least 2000rpm speeds.

https://www.ebay.com.au/itm/3-x-New-12cm-120mm-Quiet-PC-Computer-Case-Cooling-Fan-12V-Cool-Air-120-mm-12-cm/311627048558?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649

I then bought a thermal controller off Ebay which turns on a relay when the temperature gets to a preset level, and turns it off again when below. I set the turn-on point to be 30 degrees.

https://www.ebay.com.au/itm/Two-Relay-Output-Digital-Temperature-Controller-Thermostat-with-Sensor-G1/282829316281?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D2%26asc%3D20140106155344%26meid%3Dd2055906c9394159b758d3b6336e3130%26pid%3D100005%26rk%3D2%26rkt%3D6%26sd%3D152928151203%26itm%3D282829316281&_trksid=p2047675.c100005.m1851

Installation in the Door:



Installation in the Box itself:



When running, there is a small flow of air out from inside the box (actually better than I thought). This will hopefully be enough to circulate air through the box, and help out the fridge.

Additionally, the current draw from the fans and controller is far less than the extra power needed by the fridge when the box is hot (during most days in summer)

Will report back after this weekend on how it went!

[Chris Golding]

Nice idea Rob. I have been thinking along the same lines. I was wondering how well sealed the box is and therefore how much flow you actually get. I have a mkIII so I think they only have the one vent at the back of the box. If your mkIV has two vents you might get some cross flow I guess. I was thinking I might need to create an exit vent of some sort.

I look forward to seeing pics when you've finished.

Chris

[Gumb]

Has anyone actually measured the temperature inside the box on a hot day ? I like this mod a lot but with the insulation and the outer sides being white, does it get much hotter in there than the ambient temp in the outside air ?

[robstevens]

That's a good point! However I'm thinking that the fridge increases the box temperature at least as much as the sun does.

Anyway, I'm going to leave the fan controller off and let it warm up, then see what temp it gets to, and turn on the controller and see how that changes things.
All in all, it's a pretty cheap mod: total cost is less than $75... it's more just a fun experiment at present!

[Gumb]

Nice choice of fridge by the way. I love my EvaKool.

[Cruiser 105Tvan]

You must have lots of room at the end of that fridge, to be able to fit even more in there.

[Harry Lissimore]

robstevens,

I'll be very interested in the outcome.  Our Topaz ARB fridge box got up to around 40 deg C when the outside temperature was about 33 with sun intermittently shining on the box.  I have been considering adding fans to remove some of the hot air, but the Topaz fridge box only has the filtered air vent on the hatch door.  It also is vented to the hatch next to it, but when that hatch door is closed it is still a sealed system.  I often leave the second hatch door open when stationary as well as the fridge hatch door to try and get some flow of breeze through.  Perhaps it works.  I also put a silver car windscreen heat deflector on top of the fridge hatch and drape it over the hatch door to try to keep the suns heat down.

[peter_mcc]

When running, there is a small flow of air out from inside the box (actually better than I thought).

Some other simple things to try:

• tape up all the gaps around your frame so that the air moved by the fans has to go through the filter (and not around the edges)
• try reversing the fans and see if they "suck" more efficiently than they "blow"

[Wetjala]

Nice solution! I have been contemplating doing the same thing because I have experienced a couple of thermal trips of my fridge. I made a BIG mistake when I configured my MkIV as I should NOT have asked for the shelf to be installed into the fridge box as it reduces the overall volume of air circulating around the fridge. (Luckily though, when I bought the 60l fridge from ARB, the salesman talked me out of the getting the bigger 78l when he heard it was going into a T-Van!) I'm toying with the idea of getting rid of the shelf as, in my case, it is of little real value to be honest.

I find the fridge box can get very hot if the T-Van is exposed to full sun when it is parked up so now I tend to set up the grey shade sail across the front of the T-Van to provide relief from direct solar thermal load and it makes a hell of a difference! When traveling on the road it's not so much of a problem as the airflow across the box helps with heat transfer. Also, as soon as I pull up or am staying in camp, I always keep the fridge box door ajar if not fully open to help keep it relatively cool.

Trips & Traps for (potential) T-Van owners (and my list is growing!!)

[robstevens]

Well, the design was tested over the weekend, but as the weather wasn't particularly hot, full results are not yet available!

Main thing I found is that even in cool shade, the fridge raises the internal temperature by at least 4 degrees compared to the outside temperature. 

Now have to wait for a really hot day and see how the temperature internally compares to the outside temp, both with and without the fridge on.

[Chris Golding]

• try reversing the fans and see if they "suck" more efficiently than they "blow"

I reckon Peter is right here. It's important to have positive pressure in the box (ie drawing air in) as this prevents dust ingress through any gaps in the seals etc.

Chris

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[robstevens]

Good idea - Fans now reversed, to get positive pressure in the box. Now getting an airflow inwards, which goes out via the filter in the middle-rear of the box.