Refrigeration 101 – READ FIRST!

[mckdelbu]

Before you start building your keg box, it’s good to get a short primer on the working of a refrigeration system.

The basic principle of any refrigeration system is not to make things cold. Well, it does that, but it does so by REMOVING HEAT.

So, a few basic rules to follow when building a keg box are:
1. Prevent heat from entering the box area. Insulate it well!
2. Maximize the efficiency of your cooling system by keeping air inside the box moving.
3. Never forget to insulate UNDER the floor!
4. Don’t open the door unless you are changing out the keg or defrosting.

Take a look at this schematic diagram of a basic refrigeration system:

T1 is the air and items inside your keg box.
T2 is the freezer plate inside your fridge.
T3 is the rear coil usually on the back or the fridge, some new models enclose this coil.
T4 is your ambient room air.

Heat needs to be removed. That’s our entire goal. So, if you can speed the air passing the freezer plate, you will speed cooling inside the keg box.

Think of the big soda coolers at the local 7 11 or liquor store. Open the door and you can hear those fans blasting away.
For our purposes a small 12 volt fan like the one in your PC will work fine and is very quiet. You can buy cooling fans on Amazon.com

On the outside of the fridge, we need to expedite the departure of heat from the back of the unit. While the older “exposed” coil units do seem to work a little better, just keeping air circulating back there is a good idea for both the exposed and enclosed coil models. It helps cool the compressor too, making it last longer.

Many people have asked if this model fridge or that model fridge will work…
Here’s the test…
Plug it in…wait 15 to 30 minutes.
If the freezer plate gets cold to the touch, it will work.

If your unit does not have a freezer plate, it will still work, but the more surface area the better, so fill a bunch of old soda bottles with water and stack them in the fridge.
Then position your fan to blow the relatively warmer air from the keg box across the water bottles. You may have to set the thermostat setting to near it’s max.

Hopefully this quick, rather unscientific explanation will help.
Post any questions or comments.

[sam2014]

If you are having problems with the DIY keg box cooling, here are a few tips…

How often are you opening the door?
Every time the door is open, you slow down the cooling process.

Does your fridge have a freezer plate? how cold is that getting?
Your target low temp is 36F. Upper low is 44.

Are you measuring the temp using a wired or wireless remote?
That eliminates the need to keep opening the door and slowing the cooling process.

If you have a freezer plate that is below 32’F, then passing air over it will transfer heat away faster.
You can use a few scrap heat sinks from an old PC CPU to increase surface area.

My freezer plate gets down to 10’F and forms frost.
If you have no frost on your freezer plate, you may have a clinker fridge.

I’ll move this over to the forum.

Cheers
Steve

[bpwdmin]

Before you start building your keg box, it’s good to get a short primer on the working of a refrigeration system.

The basic principle of any refrigeration system is not to make things cold. Well, it does that, but it does so by REMOVING HEAT.

So, a few basic rules to follow when building a keg box are:
1. Prevent heat from entering the box area. Insulate it well!
2. Maximize the efficiency of your cooling system by keeping air inside the box moving.
3. Add an aluminum heat sink to the freezer plate and blow fan air past it.
4. Never forget to insulate UNDER the floor!
5. Don’t open the door unless you are changing out the keg or defrosting.

Take a look at this schematic diagram of a basic refrigeration system:

T1 is the air and items inside your keg box.
T2 is the freezer plate inside your fridge.
T3 is the rear coil usually on the back or the fridge, some new models enclose this coil.
T4 is your ambient room air.

Heat needs to be removed. That’s our entire goal. So, if you can speed the air passing the freezer plate, you will speed cooling inside the keg box.

Think of the big soda coolers at the local 7 11 or liquor store. Open the door and you can hear those fans blasting away.
For our purposes a small 12 volt fan like the one in your PC will work fine and is very quiet. You can buy cooling fans on Amazon.com

On the outside of the fridge, we need to expedite the departure of heat from the back of the unit. While the older “exposed” coil units do seem to work a little better, just keeping air circulating back there is a good idea for both the exposed and enclosed coil models. It helps cool the compressor too, making it last longer.

Many people have asked if this model fridge or that model fridge will work…

Here’s the test…

Plug in fridge…wait 30 to 60 minutes.
If the freezer plate gets cold to the touch and builds frost, it will work.

If your unit does not have a freezer plate, it will still work, but the more surface area the better, so fill a bunch of old soda bottles with salt water and stack them in the fridge. Salt prevents freezing.

Then position your fan to blow the relatively warmer air from the keg box across the water bottles. You may have to set the thermostat setting to near it’s max.

Hopefully this quick, rather unscientific explanation will help.
Post any questions or comments.

[Author]

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