Tropicalising Van Fridge....

I guess that the important thing to remember is to ensure that the airflow which is by thermal induction.. hot air rises is clear and the cooling fins are free from dust and spiderwebs etc....My installation is as supplied by the van makers with a plastic vent top & bottom on the outside and dosent appear to have much of a draft... unlike other instalations where if a tissue is offered up to the bottom vent it is held there from the draft.....I also seem to have to run the fridge on around 6 to get it really cold whereas others seem to freeze at around 6... just dont know. I have seen a solar fan kit but I dont think they would do much...but with these absorbtion cycle fridges the cooler you can keep the condensor the better they work....

Rick,

Don't despair as there are things you can do to improve the airflow.....like reviewing the current installation on your van and installing new inexpensive sheetmetal baffles in the appropriate places to ensure cold air coming in at the bottom displaces hot air in the chamber. I will try and post some links for you to look at.

Regards,

Stuart

Rick,

Follow this link and all will be explained....

http://www.rvmobile.com/Tech/Trouble/vent.htm

If this doesn't help or you need more info let me know. Remember the fan is a band aid and will not do things like direct air over the components that need the draft to operate efficently. These fridges have no moving parts and by introducing some (like a fan) you are taking away the K.I.S.S principle that they operate on.

Regards,

Stuart M.

yep the small comp fans should be OK

mmm dont think your entirely right here ...a fan Correctly Installed and selected to come on in high ambients will certainly improve performance of the fridge.....

if done correctly they should not cause "more problems"

Steve Jayco know only to well about 'T' rated fridges. If the fridge is correctly installed they require no alterations. The only time alterations are needed is if the fridge is not installed exactly as per the instructions supplied by Dometic/Electrolux. Unfortunately fridge manufacturers have no control over the installation. I came across a Waeco upright last week that was not working properly - why - installed incorrectly without proper ventilation by the caravan manufacturer. It does not matter if it is a three way fridge or electric fridge, attention to detail on installation is vital for the fridge to perform to the required standard.

Sean often a computer fan will cause the fridge not to cool. If the fridge is installed correctly, and that means the vent must be above the top of the fridge as per the diagram at the bottom of this page "Almost Good Venting"
http://www.rvmobile.com/Tech/Trouble/vent.htm
If your fridge is not vented as in the diagram (above the top line of the fridge), you will have problems.
Even an non-'T' rated three way fridge should work well above 33°C. If it is new, and even if it is not a 'T' rated fridge, it would be a minimum of an ST

http://users.bigpond.net.au/goldway/page16.html

Hey Nudenut,

The info below is a direct quote posted on another forum from a guy named Collyn Rivers who is renowed for his wealth of knowledge in the caravan and camping circles. I have also carried out extensive research to confirm what is said below is true and it is. The point is that if you are trying to run a non 'T' rated fridge in the higher temp climates then you will find that the efficency of the fridge will suffer.

As I have posted above it is imperative that the vent chamber be built or modified to direct airflow over the correct components that require heat to be removed away from them using a draft to do so. Adding a fan will only move air and not direct air unless a path has been formed for the air in the first place. Pay particluar attention to the installation of metal baffles across the rear of the components as mentioned in the electrolux manuals, these sit approx. 25mm from the components creating the air path mentioned and also the top, sides and bottom of the fridge.

Quote from Collyn Rivers...

"Many (but not all) fridges in the range are obtainable with a choice
of different design operating conditions. This is not universally
understood by those selling these fridges and one needs to be
persistent and careful when buying.

Inside the fridge there is a compliance plate. On the bottom line
there is the phrase 'Climate Class' This is followed by the
letters 'S', 'SN', or 'T'.

Those fridges designated 'S' or 'SN' are designed to operate at
maximum room temperature of 32 degrees C. That designated 'T' is
designed to operate up to room temperatures of 43 degrees C.

Note there is no other way of telling which is which: the type
numbers are same.

I have recommended the 'T' rated fridge to many people and have yet
to meet anyone who is disappointed by their performance. They must be installed correctely, with adequate ventilation. The 12 volt wiring
must be specified for the heavier current draw (15 amps) of these 'T'
rated models."

Regards,

Stuart M

Incidentally they now appear to be fitted as standard in Winnebago
motor homes.

I agree with the fact that vents to allow airflow across the condenser must not be blocked. However, in high ambient conditions a fan assisting the movement of airflow will lower condensing pressure and subsequently the back pressure. The refrigerant being temperature pressure related will be colder!!!

Having said all that … a condenser which does have a restricted airflow can be greatly improved upon by the installation of a fan…..the correct size fan will overcome the restrictions and if of adequate size can allow the fridge to run as if it had been installed correctly with adequate standard vent relief…..fact!!!! ….and not an engineering secret

Hey Nudenut,

You can always place a fan in a poorly designed vent chamber to move air around but then that defeats the purpose of the design intent of the fridges....that is they are designed for use without them and if where possible the correct fridge is purchase to match the climate where it will be used then the fan is likely to be unnessary.

I still say the major problem in the correct installation of these fridges is there is no upfront thought and it is a little bit of thought upfront in the design of the enclosure that will save all the screwing around adding fans etc. I would also say that most existing installations can be corrected (at least the ones I have seen so far) without the addition of a fan by adding the air path that I continued to refer to and as per Electrolux guidelines......and that is fact!!!!

I might also point out again that its not just the input and output vents that make up the installation but baffles and formed chambers in the rear vent chamber as well as the addition of insulation around the fridge that will ensure a successful install.

Regards,

Stuart M

so now you agree...that they do work with a fan...and can do so more efficiently?

my argument has not discussed poor installations....rather someone asked if a fan would help....and yes it will!

between you and me...poor airflow over the condenser of any refrigeration system reduces its efficiency.... that also includes airconditioning systems for the house or car

Hey Nudenuts,

Where did I agree with the installation of a Fan....what I said was you can always install a fan to move air around......I didn't say it would fix the problem.

What I have been saying and you know exactly what I have been harping on about and that is get the design right before, during or after the install and your fridge will be efficent and operate as designed without adding any active device.

The most likely scenario where a fan has been added if the install is correct and as per manufacturers recommendation is to try and overcome the use of non tropical rated fridges in tropical rated climates and improve there efficeny.

This again is poor design and/or poor product selection.......

Regards,

Stuart M.

Also Nudenuts,

The original post said that he tried adding a fan.....and the result was and I quote "I tried it on my Jayco van and did not notice any difference"

So I say you can tell him to keep adding more fans to your hearts content but more the original installation needing improving and that is what I have been preaching......

You can give a man some food to last him today or give him some seeds and show him how to grow and that will feed him tommorrow...

Regards,

Stuart M.

The name is nudenut! So drop the ‘S
please.

Fit a fan and it will fix the problem!!!

You need some engineering experience to see how….some persons remain blind by choice!

Yes get it right as per the manufacturers instructions! I agree!!

Could you please tell me what the difference is between a standard fridge and your intereptation of a tropicalised fridge? No such thing if its simply refering to high ambients ….i was always taught that to “tropicalise” something are for humidity problemsor the very wet environment if outside…. Eg a Tropic Proof electric motor. You can have high ambient temps and not be in the tropics, right?

“The original post said that he tried adding a fan.....and the result was and I quote "I tried it on my Jayco van and did not notice any difference"”….obviously not the right one, or fitted incorrectly! because and read my lips…a fan correctly installed will increase the airflow over over the condenser and there-fore increase the efficiency of refrigeration…..and as I guess you’ve most like seen one, why do refridgerated air conditioners have condenser fans?....no condenser fan, and the physical size of the condenser would be (mmm taking an educated guess here, after all i have been in the game for 38+ yrs) twenty times the size if wanting to use natural convection to condence the refrigerant.

And I reiterate, a fan, correctly selected and fitted will overcome a restricted airflow if no other solution is available for what ever reason.

Good Morning Nudenut,

At least I have reffered to you by name......you could do the same..!

As for engineering experience....I may not be a refrigeration mechanic but I am a sparky by trade, with electronics & comms certifcates and have worked in many different industries including large HVAC plants....so I do have some idea of how things are designed and intended to operate.

If you persisit in your advice on fitting fans to this guy and you are such an experineced engineering dude then you should have advised in your first post specifically how to add the fan rather than just saying and I quote "yep the small comp fans should be OK" rather than piece by piece.

As for why fans are added to AC units described by you it is because that is how they are designed.....compressors, fan motors, gas, thermostats, indoor/outdoor units blah, blah, blah. Heat rejection!!!

I am not some useless pup and have been around (24 years experience) and the thing that I have been very careful about doing in the past is to try and answer other forumites questions with as much information as possible that I have at hand based on my experince and not just throw away one liners.

This forum is also not about who has the biggest nuts and how many times they have been used but more about ensuring ideas are put forward, analysed and implemented to a successful outcome.

So place that in the fridge and freeze it....but I am sure you will want the last word so start thawing!!

Regards,
Stuart M.

Stuart,
I am plum tuckered out trying to get you to accept the fact that condenser fans will aid in heat rejection..............whoopie at least you know what the condenser does....same as a radiator in your car ...rejects heat eh? why does it have a fan?....cos it make things work more efficiently.
Maybe I need to tell and or show you how to install one correctly to get better performance during high ambient conditions.

and what is your interpretation of tropic proofing eh? you should know....your a sparky right.

Hey Stuart,

click on waeco link on Forum page and select fridges freezers and tell me what the two little round things are below the carry handle and what do you think they are there for?

Sorry the link doesn't work...you will need to see it the hard way!

Its the smaller fan....big one is very noisy.

rgds