Correct Air Flow on 3 way fridge?

Submitted: Wednesday, Mar 09, 2005 at 09:39
ThreadID: 21074 Views:1927 Replies:5 FollowUps:2
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Hi,
Just wondering what the corresct direction of air flow would be on the back of a portable 3 way fridge?

Details:
3 way fridge mounted in the back of a van.
I have 2 computer fans mounted in a small frame that can be placed either on the top of the rear vents or on the bottom.

Question?
Would it be better to have the fans on top sucking the hot air out?
Or on top blowing cooler air into the vents?
Or on the bottom either blowing or sucking?

So it comes down to whether its better to blow or suck?

Cheers
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Reply By: Nudenut - Wednesday, Mar 09, 2005 at 09:57

Wednesday, Mar 09, 2005 at 09:57
hot air rises...does that tell you anything?
so the natural (unaided) air flow will be from bottom to top
so the fan must do the same
AnswerID: 101701

Follow Up By: Member - Craig M (NSW) - Wednesday, Mar 09, 2005 at 10:09

Wednesday, Mar 09, 2005 at 10:09
Hi Nudenut,
Thats the usual with hot air.

But I was under the impression that 3 way fridges are tempremental when it comes to the air flow through the coolling tubes etc.
If you upset it they dont work as good etc.
So if you suddenly start blowing air onto the back fromn the bottom isnt it liable to upset the natural flow?

Cheers
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FollowupID: 359551

Follow Up By: Nudenut - Wednesday, Mar 09, 2005 at 10:52

Wednesday, Mar 09, 2005 at 10:52
Craig, you didnt read what I said too well...
the airflow must be in the same direction as the natural unaided airflow....as hot air rises it causes a natural draft or convection current if you like...
the fan must be installed so that the airflow is the same...does not matter if the fan blows or draws (sucks) air over the coil ..just so long as its in the same direction
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FollowupID: 359558

Reply By: Keith_A (Qld) - Wednesday, Mar 09, 2005 at 10:34

Wednesday, Mar 09, 2005 at 10:34
Hi Craig - Both methods will significantly improve the operation of your unit.
If the fan is on top, AND the air it sucks must go throught the cooling fins,
there may be a slight gain in efficency over the bottom install. eg the cyclone effect (you are removing the hot air making room for more to enter at the bottom.).
Some install notes suggest using baffles between the outside van wall and the fins to ensure the air must pass through the fins (rather than bypass them via air gaps).

I used a thermostat from an electronics store (Jaycar). Screwed to the exhaust vent of the fridge, it is normally OPEN. When the temp reaches 50 deg, it closes thus completing the 12V circuit and the fans come on. The thermostats come in 50 deg; 70 deg and 90 deg (I think). Take care though as they also come in normally open and normally closed versions. With only 1 fan, ice formed in the freezer compartment in 3 hrs. (5pm Feb 2005 - Brisbane).
(In addition, a slower fan inside the fridge may double the efficiency - fan forced.)
Regards...........
AnswerID: 101708

Reply By: iMusty - Wednesday, Mar 09, 2005 at 14:01

Wednesday, Mar 09, 2005 at 14:01
Craig M

On post 20658 "how fast should a fridge take to get cold", PJ Chris placed 2 links which will explain simply all you need to know about airflow.

PJ Chris's reply/post is a fair way down the thread.

AnswerID: 101742

Reply By: Member - Craig M (NSW) - Wednesday, Mar 09, 2005 at 14:30

Wednesday, Mar 09, 2005 at 14:30
Hi,
Thanks for the info.
I guess I shall have to do a bit of experimentation.
And see which position makes any sort of difference.

Cheers
AnswerID: 101745

Reply By: pixiemops - Wednesday, Mar 09, 2005 at 20:31

Wednesday, Mar 09, 2005 at 20:31
hi craig . I just mounted it under the condenser fins blowing up .....Works for me see my latest post re improving the insulation .......overall the fridge now works unbelievably well better than i could have imagined ..........was thinking of upgrading not now.............

cheers
AnswerID: 101822

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