Brew Fridge Modification - Exhaust Fan

[Metal_Gman]

Used in this is;

1 Heller HEFM250 250mm Exhaust fan.
A large amount of MDF
An arseload of duct tape (You'll need approx 2 large rolls)

End Result;

As the fridge has exposed heat exchangers, it makes for an extremely effective cooling solution to give the poor fridge motor a break. And reduce the electricity bill

Sorry about the not so great images. Stupid Nokia E75 struggles to take artificial light photos

Enjoy!

 

[jonocarroll]

A couple of questions...

1. Where is the intake for the air? Or do you expect the exhaust fan to create a low pressure inside your box? In which case, how will this cool? If the air is entering from the top, you are moving room temperature air from outside the box, through the fan, back to outside the box. If you are moving air from the bottom, past the coils, then out, then you may get some effect... unless:

2. Is the additional power used by the exhaust fan actually less than the power saved by cooling the coils? Presumably your house is cooler than the hottest temp of the coils, so you are then hoping that the temperature difference between the air and the coils is maximised, to optimise the efficiency.

I like the phrase someone used to describe a fridge - "a better term would be kitchen heater" - and that's true; you add more heat energy to the room than you remove from the contents.

While this may help the fridge dissipate the heat better, I don't think the cycling of power has anything to do with that - it's the temperature inside that controls it. If it's less efficient, the coils just get hotter. Thus the fridge may very well run for the exact same amount of time, and along with running an extra fan, you may well be increasing your power use.

Food for thought from a physicist.

 

[Metal_Gman]

The rear of the fridge is only semi covered, with the exhaust fan venting upwards, you are perhaps correct in that the coils heat up quickly probably because the design is not really effective at all.

But I have noticed a dramatic difference in the fridge's ability to cool down rapidly, I had it @ 12C for a secondary ferment, cold crashing now at the moment, it's managed to drop several degrees quite quickly.

Also the coils used to be very hot to touch, now they're mildly warm. I guess all i've really done is make up for a design defficiency which was killing the fridge motor. So it should extend the fridge's life a little bit, certainly the fans extra 60watt power usage would be much less than the fridge motor running at full capacity losing a huge amount of efficiency at full speed i would have thought.

 

[komodo]

4wd guys often add secondary fans to their waecos / engels etc to aid in efficiency. They have to worry about how much battery power they have - not something too many people wonder about with houses. Also many of the newer fridges have this type of setup though using a barrel type fan for reduced noise and space.
I reacon it should work well.

 

[glaab]

looks like a fire waiting to happen

 

[A3k]

It would be good if you could run it off the fridges thermostat so that it only runs when the fridge is requiring the heat transfer.

 

[Metal_Gman]

It runs off the thermostat I use to set the fridge temp I have an ext 3 prong plug one,