Fan cooled Trailblazer

Am still not sure how affective it is as I havent had it running succesfully yet that is, cutting in and out with the compressor, I tried hooking it into wires between thermo and motor - starts ok with compressor but stops later when comp. continues as is back feeding through the wiring keeping the comp. running.....make sense?? - Had trouble writing it to..

milo...

I have heard the minimal draw of fan allows the compressor to run cooler thus less often, thus less draw on power. Hopefully when ever I get it running!

milo...

OK - I just went and took my 'fridge to bits.

Down next to the compressor is a controller/terminal box sort of thingy.
The terminals (from to to bottom) are: -,+,+,F,D,C,P,T.
The fan is connected to terminal 3 (the second "+" terminal) and the F terminal.
In my case there is nothing connected to the C and T terminals.

Hope this helps.

Cheers
Stephen J.

Stephen j,

Curious you have no connection to C & T, that is where my thermostat is hooked to. Which controller model/Danfoss do you have?

Just curious
............................................................

Stephen[WA]

I fitted a blower to 'save' the compressor....don't think it does much for 'cooling' the contents of the fridge!

cheers all

yep, your right Jimbo.

But one can make the fridge more efficient by blowing air across an otherwise nomally convection draught condenser....this must also done be correctlly if the condenser is multi-pass type.

As far as I am aware the trailblaza uses the external skin of the fridge as the condenser...the condenser piping is taped to the internal skin during manufacture (as is the evaporator piping) and the foam insulation is pored in to the cavity...so do not drill holes into the outer or inner skins...you could put a hole in the pipe...and that means throw it away and buy a new one.....

IMO fitting a fan inside the compressor campartment isnt going to do a lot of good....

The fan blowing on the compressor should increase the motor life by stopping it from overheating. I believe Engel had that problem for a while after they changed to the current refrigerant gas. Blowing air over the condensor allows for a faster transfer of heat & shorter running time. Fridges in cars & campers particually those fitted in enclosed boxing systems need a fan to remove the heat build up where a fridge in the open air would get little advantage.
Cheers Craig......

Crackles...both fridges have totally different compressor types....

"Fridges in cars & campers particually those fitted in enclosed boxing systems need a fan to remove the heat build up where a fridge in the open air would get little advantage."....the danfoss compressor is designed to operate in enclosed boxes. as most domestic fridges are..
the heat losses from the motor are tranfered to the refrigerant and disipated via the condenser.....the only type of compressor that will benefit from air being blown over it is one that requires oil cooling...and the Danfoss does not

"Blowing air over the condensor allows ............................shorter running time"...this is only be true if the condenser is inefficient or has inadequate rejection capacity at any selected temperature that one wants to compare it too... and applies to both convection and forced (fan) draft condensers...it would then allow for shorter running times as the condenser pressure and would give rise to the system having minamal or zero flash gas entering the refrigerant control device...apologies if to technical

Makes sense to me Nudie.

Cheers,

Jim

My point with the fridge being stored in an enclosed boxing system was that it will always be more efficient if the heat can get away from the condensor & a fan will certainly help. I understand the compressor is designed to opperate in a box but when all the vents are enclosed in another box or gear packed around it then a fan must assist in some way to keep it running at the design temp.
Nudie, what are the 2 totally different compressor types you mention?
Thanks Craig.........

If you wanted to reduce the heat load from around the fridge carcase, wouldn't you mount a fan or two externally of the carcase and blow the hot air away from the outside skin and help dispose of the heat that way? I have my fridge inside a mesh enclosure so that there is plenty of free air surrounding the fridge. The temperature still builds up to near 50 degrees celsius on a hot day but the inside contents are still beautifully cold.

Crackles, the compressor in the danfoss is a reciprocating type while the fridge in the Engel is a swing type...basicly operates similar to a soleniod while the plunger acts as the piston...

The idea of fitting a fan inside the with the compressor sounds good to the uninitiated, but in reality it would be a waste of time...the vents in the compressor compartment is for the heat generated from the 240v - 12vdc transformer to escape...if it has one.

Des, yes thats what one would do but it would be a headache to mount and keep safe etc etc
I use a flat piece of thin ply same size as the fridge with 2 vertical 20mm square slats same height as fridge fastened to one side at each end of the ply and stick this next to the fridge... it gives a thin air vent space allowing the foul er hot air to vent

"The idea of fitting a fan inside the with the compressor sounds good to the uninitiated, but in reality it would be a waste of time...the vents in the compressor compartment is for the heat generated from the 240v - 12vdc transformer to escape...if it has one."

Sorry Nudie but your theory on the compressor fan seems to go against arguably one of the more efficient fridges that being the Autofridge. The condensors are the Aluminium sides, they have no 240 Volt transformer, yet they have a fan blowing directly on the motor????

I would also have to agree with crackles on this one, but as to my own 'initiated' opinion on fitting this fan to my fridge is, 'If something is working and is hot, trying to keep it cool can only do better for it.'
Time will tell, as testing is underway, - if it saves 1 or more cycles a day it will have done its job!

milo...

I can only say ...
its got me buggered why they need to do that..

i wonder if they also have some condenser on the back panel of the compressor compartment?

I dunno............but they, the danfoss comp, do not need it

Maybe i can say something!

Crackles........your not trying to mislead me are you?

Since when could one use outside skin on the auto fridge as the condenser?
"The interior cabinet and the EXTERIOR construction of the AUTOFRIDGE ARE white FIBREGLASS"

No heat transfer thru fibreglass.

This would then suggest that it may have an aircooled condensing unit?....which has a fan!!

No I'm not misleading you. If you look at the fridge photo on the link you posted both of the long sides have aluminium panels recessed into the fibreglass. (Darker shade of white) On the 73 litre model they measure 750 X 400 on each side & with such a large surface area to transfer heat may help explain why they are so efficient. They suggest a minimum gap of 40mm around the sides for ventalation.
Cheers Craig..........