12 replies to this topic

[Rodders]

Our last caravan was 12 years old and in high ambient temperatures the fridge suffered, so cooling fans were fitted  , our new caravan is just over 2 years old , and STILL fridges can not cope with high ambient temperatures , so fans will have to be fitted . why do fridge makers STILL use absorbtion technology, it just does not  work when the air temperature is the high 20s .or why not fit cooling fans ex factory to assist the air circulation
For the time being I have a desk fan pointing at the vent grills to keep the fridge working at its best whilst we are down here in deepest France with daily temperatures reaching as high as low 30s

[Grandad Graham]

Somewhere WAY back thee;s a thread about this where quite a few of us who regularly travelled to warm climes have fitted a large computer fan to the back of the outside grilles to drag the hot air out at a higher speed.Mine is run via a fused 12v lead run from the main fuse area but direct from the battery

[RogerL]

The gas part of the multi-fuel source facility can only work as an absorption type, it's simply not possible to build a compressor-type gas fridge.

Aussies use 12v compressor fridges in their tow vehicles to ensure a never-ending supply of cold tinnies - I guess with a solar panel for on-site use.

How do caravanners from Southern Europe cope?

[Rodders]

RogerL, on 28 July 2012 - 07:26 AM, said:

How do caravanners from Southern Europe cope?

Here at Camping Neptune , as well as the kitchen sink , they appear to cart a domestic fridge with them , although on other sites I have been to you can ( at a PRICE) rent a domestic fridge

With regard to fridge fans , in our last van I mounted 2 computer fans behind the top grill and that did the trick
With this van I may go one step further, as well as mounting  2 extracting at the top I am considering  2 at the bottom pulling air in

[Beejay]

Dometic literature indicates that a temperature drop of up to 30° is possible with absorption fridges and correct installation  is the best way of achieving the best fridge performance.  It follows that at 30°C ambient temperatures the fridge will be struggling cope

A  sealed 45° sloping plate across the full  width of the back of the fridge diverting the rising air to the top vent  combined with a floor vent is the best arrangement but rarely seen on U.K. 'vans.  If the worktop above the fridge gets warm it i may indicate that  the installation could be improved.
Reducing the gap behind the fridge unit and the caravan wall to less than 25mm   ensures  the air flow passes over the cooling fins and not  around them.
If fitting a fan the  Dometic fan kit is designed to be mounted just below  the finned element and it is suggested that mounting fans in the vents has little effect..

[Hawkeye]

Beejay, on 29 July 2012 - 01:01 PM, said:

...
  combined with a floor vent is the best arrangement but rarely seen on U.K. 'vans.
...

Taking the cooling air from the space between caravan and ground is obvious (where do you put your case of beer when the fridge is full?) but caravan manufacturers ignore this. When I fitted an RM122 fridge to our first van, the installation instructions called for a big floor vent. I have fitted a fan to our currenb van to draw cooler air from under the van to assist cooling.

[Rodders]

Beejay, on 29 July 2012 - 01:01 PM, said:

fans in the vents has little effect..

That just an excuse for not fitting them , my ,and others , experience is totally to the contrary fans  DO have an effect,  a fan drawing hot air out from behind a fridge MUST and does help , even on this trip just putting a desk fan against the lower vent improved the fridge performance no end, we have had 14 days of 30c+ and after the first couple of days when the fridge barely kept the milk cool I put the desk fan in place and the fridge then worked as expected  . so fans it is a soon  as I get home

[RogerL]

Hawkeye, on 30 July 2012 - 09:34 AM, said:

Taking the cooling air from the space between caravan and ground is obvious (where do you put your case of beer when the fridge is full?) but caravan manufacturers ignore this. When I fitted an RM122 fridge to our first van, the installation instructions called for a big floor vent. I have fitted a fan to our currenb van to draw cooler air from under the van to assist cooling.

Floor vents are rarely used because fridges are often mounted over wheel arches - even when they aren't the water ingress from road spray becomes an issue - this can be overcome by well designed shielding but these are caravan makers !!

[gary]

Rodders, on 30 July 2012 - 08:18 PM, said:

........... even on this trip just putting a desk fan against the lower vent improved the fridge performance no end.........

While I actually totally agree with Beejay, particularly regards installation, you have hit the nail on the head? it's the bottom of the cooler unit that overheats, not the finned bit at the top, that's meant to be hot!
Hence a floor vent directly under the bottom part works best as air flow must pass over the bottom pipework, rather than the lower vent being in front and far too far away so has a route staying away from the heat!

As for the why? absorption fridges are silent, pure and simple

[rds60h]

As Gary states I think the main reason for absorption fridges is that they are silent running.
And for this "luxury" the running cost of the fridge on electric is about triple the cost of an ordinary domestic compessor type fridge !!
If you only use your fridge on 240v electric then it may be worth considering fitting a domestic fridge which are cheaper to buy and to run, however make sure it will fit. As many caravan fridges are positioned over the wheel arch a domestic fridge will not fit into that space.

[Beejay]

gary, on 31 July 2012 - 10:40 PM, said:

Hence a floor vent directly under the bottom part works best as air flow must pass over the bottom pipework, rather than the lower vent being in front and far too far away so has a route staying away from the heat!

Whilst I have no doubt about your expertise in these matters what you are indicating appears contrary to what Dometic state.

As fins are designed to  improve the removal  of  heat  surely  it must be the finned section of the fridge unit  that  requires cooling?  The Dometic fan kit is designed to be mounted below the finned section despite the fact that mounting a fan in a vent opening would be much easier.

A good link to how an absorption fridge works here

http://www.a-tconsul...ch/fridges.html

Edit:  Dometic fan fitting instructions:

Mount  the fan between absorption unit and  the condenser as near as possible to the absorption unit. Make sure that the fan is tilted at the same angle as the condenser and the airflow directed upwards.

[Metz]

Hi, having been on many fridge courses in my time, your all right up to a point, the facts of the matter are as long as you have a good air flow across the whole of the cooling unit the fridge will work correctly within it's operating parameters, providing the gap between the cooling unit and the rear wall are correct, and the fridge is installed according to the manufacturers instructions, I myself have never had a problem with a fridge in a caravan, even in extreme temperatures.

[RogerL]

Forget what Electrolux/Dometiq or Thetford say - it's my experience that fridge cooling depends entirely on how well, or more typically how badly, the caravan manufacturer has actually installed the fridge.

Absorption fridges are designed to operate with a totally sealed rear chamber - caravan manufacturers have still to grasp the concept of "totally sealed".