Interesting Brian, does that mean you would have to have the fans on at all times? even on cooler days?

I have the fan on the top vent but no insulation yet, I do use a shade over the area on that side of the Avan though.

Thanks Brian a good post.We have done the fans and the isulation as JC sugested with great results and will try your modification as well. The other thing that we have done that we found afective is to put 2 well fitting plastic boxes in the freezer to act as draws we find this tends to trap the cold air when the freezer door is open a bit like a chest freezer.
Dave

HI
That Is why I always say FIT baffles to ensure:
[1] ALL the cooling air flow is directed through the condenser FINS
That may mean a horizontal baffle from the condenser fins to the van wall/ fridge accessr door
IF possible fit the fans directly under the condenser fins SO ALL the air is blown through the FINS
IF they are fitted THERE ,then the external vent grills are not a problem & still allow good air flow when the fans are not running [ IF not partialy blocked off ]

[2]Fit a verticle baffle between boiler & condenser & other rear components
limits radiated heat into the condenser area

do not use the fan air to cool the boiler
You are paying to heat the BOILER why cool IT?
,
Remember what is required:
is directing all the cooling air through the condenser fins
allowing normal flue operation of the boiler BUT not cooling IT
Allowing /obtaining MAXIMUN chimney draft effect to minmize the need for the fans
THe worst thingto have are full length vent grills
They compleetly stuff any chimney draft effect


FOr automatic fan operation, fit a 50C nornally open thermostat Jaycar#ST3831] on top of the condenser fins about midway along


PeterQ

hako wrote:

---

Brian, I'm no engineer (it shows!), but by blocking off the grill in the manner you describe, you would be reducing the nett airflow over the condenser when the fans are not in operation thereby reducing the efficiency of the fridge. You may then have to use the fans all the time otherwise efficiency will suffer. Just a thought.
Regards
Denis

---

 

HI Hako

Yes ,

100% correct ,

. NOT a good idea .

All one needs to do is apply a bit of physics ,to understand what is requirec & what may be detrimental at times

That includes using natural draft effects as well as fans

 

 

PeterQ

brian wrote:

---

I don't use any special ducting, vent alterations or fans either inside or outside, and my fridge maintains cold temperatures right up into high ambients and on any angle, and I can open the door as often as I like....Ohhhh hang on, it's a compressor fridge..lol

---

 HaHaHaHaHa

and

Ditto..lol..

Briche I had the same problem but took a different tack. The problem I had was the gap between the fridge and the wall of of the van As the air from the bottom vent was taking the path of least resistance and flowing between the wall and the cooling fins then bottling up at the boxed area at the top of the fridge.

Mod 1. Installed a false MDF wall to reduce the gap between the wall and the fridge down to 10mm.

Mod 2. Installed a curved alum sheet from the to of the fridge to the top of the vent. The air now can flow out the vent without the bottle neck. Remember that the easier the air flows out the more (draft) cooler air flows in.

Mod 3. Insulated the rear sides of the fridge so that the air is drawn from the bottom vent only.

Mod 4 Installed a fan through the floorat the base of the fridge to draw the cooler air in from under the van. (installed a dust sheild in front of the fan).

Mod 5. Installed a tube fan above the cooling vents.

The fans are on a 3 way switch so I can have bottom/top/all on. It is important to remember that the air flow can not be to fast as it needs time to absorb the heat from the fins. I can now maintain around 3 degrees in Nth Qld summers and only use the fans if the sun is on that side of the van. As long as SWMBO does not hold the door open while she makes up her mind what we are going to have for tea.

Wassa

 

HI Wazza

Yes,If the fridge is roof vented, then  a fan in the top orks great provided as you say any side vents above the condenser line are blocked off again 

That is actually the way I have done my motor home  

One fan under the condensor   ,baffled to the side wall so very little cooling air can bypass the fins, so no cooling air is wasted.

Then made a tube to fit under the roof vent with a fan inside the tube

I actually used small car fans in both situations ,as I did this a long time ago [.about 20YEARS ago ]They are thermostat contrlled by an old stem type thermostat that I had at the time , tied to the top of the condensor fins 

Reason I put it there is because it is the coolling of the refrigerent that counts & is required

They very successfully reduce t,he refrigerent to near , ambient temp [before it enters the evaporator ' & the fridge has operated almost as normal in 40C temps

AS in my earlier post ,I also used a vertical baffle behind the fridge to keep the boiler heat away from the rest AND to not cool the boiler

 

I also packed foam insulation ln the side gaps & the one above the fridge BODY

one little comment on your post ,if you do not mind ,

The faster the air flow the better the cooling of the fins

I  wired  the fans  via a switch that allowed  series or parallel operation [slow or full speed ]

while slow was ok in the lower high temps  when temps went real up full speed wswas needed

In the end I just left them on full speed [paralled]

Each run time was ,usualy,only a few miutes

 

PeterQ

-- Edited by oldtrack123 on Wednesday 8th of January 2014 11:50:20 AM