Applying panneling on sides of keezer???

[firefly765]

I'm dialing in my keezer build & want to apply wood flooring to the sides of the freezer using liquid nails (or open to other suggestions). Obviously not covering the vents or drains. Is there any problem with heat or ventilation doing this? I'm specifically looking at this freezer:

http://www.bestbuy.com/site/Frigida...hite/9757311.p?id=1218202121298&skuId=9757311

Thanks for any help.

 

[passedpawn]

The walls of the freezer get hot. I'm assuming this is where they dissapate heat removed from the compartment. Putting anything on the walls of the freezer will reduce its efficiency. At least that is my understanding of what's going on in them.

I know a lot of guys clad them with paneling to build their keezers. I wonder how much longer they have to run to maintain the set temps. Might not be a big deal.

 

[Decypher]

This will absolutely affect the performance of your freezer. The condenser coils (where the refrigerant goes from hot to "not so hot") is on the outside wall of the freezer under the outermost skin, most likely the side, not the back. To check, turn the freezer on, and wait about five minutes, you will be able to tell where the condenser coils are by feeling the side of the freezer. Whichever side is the warmest is where the coils are. If you put wood paneling on the side of the freezer it will insulate and reduce the heat dissipation of the coils therefore making your freezer's efficiency much lower and possibly not allowing the unit to get to the desired temperature on a hot day.

One way to combat this is by adhering 2" x 2" strips of wood vertically to the side with the condenser coils near the corners then attaching the wood paneling with finishing nails to the wood strips. Make sure to leave it open at the top and bottom so that air is allowed to flow across the coils properly. You can also use computer fans to increase the air flow, but it shouldn't be necessary.

 

[Jester369]

I run my keezer with a 1" gap and a duct fan that runs whenever the compressor is on. It doesn't seem to run any more frequently than before I enclosed it. There is a thread somewhere on HBT that talks about the R value of 1/4" wood - seems to me it was pretty low, almost negligible, but adding an uncirculated airspace dramatically increases it. Either attach it directly, or have an actively ventilated airspace.

 

[firefly765]

This will absolutely affect the performance of your freezer. The condenser coils (where the refrigerant goes from hot to "not so hot") is on the outside wall of the freezer under the outermost skin, most likely the side, not the back. To check, turn the freezer on, and wait about five minutes, you will be able to tell where the condenser coils are by feeling the side of the freezer. Whichever side is the warmest is where the coils are. If you put wood paneling on the side of the freezer it will insulate and reduce the heat dissipation of the coils therefore making your freezer's efficiency much lower and possibly not allowing the unit to get to the desired temperature on a hot day.

One way to combat this is by adhering 2" x 2" strips of wood vertically to the side with the condenser coils near the corners then attaching the wood paneling with finishing nails to the wood strips. Make sure to leave it open at the top and bottom so that air is allowed to flow across the coils properly. You can also use computer fans to increase the air flow, but it shouldn't be necessary.

Seems like a bad idea the more i think about it. I was thinking of instead of adhearing the strips directly to the freezer, framing out a whole wood framed box with a fan (maybe something a little more substantial than a computer fan) mounted on the bottom blowing air up.

 

[Jester369]

Take a look at my build writeup. You can see how I went about it.

 

[firefly765]

Take a look at my build writeup. You can see how I went about it.

Funny you responded, Jester. I was already reading your thread. That fan you mounted on the bottom, What kind of fan is it? Where did you get it? How much$$? How is it wired?

Also the coffin box on top. Did you just cut a hole in the lid with a sawzall the size of your coffin box? I was thinking of just cutting a approx 6" X 24" hole and not using a fan for circulation.

Really nice job on yours! I'm planning something very similiar.

 

[billc68]

I did it, not knowing any better, no issues yet. Just starting to get hot around here, however they Keezer is so much more effecient than a Freezer, I am sure it makes little difference. I do like that idea of allowing an air space, I did not.

 

[Decypher]

I run my keezer with a 1" gap and a duct fan that runs whenever the compressor is on. It doesn't seem to run any more frequently than before I enclosed it. There is a thread somewhere on HBT that talks about the R value of 1/4" wood - seems to me it was pretty low, almost negligible, but adding an uncirculated airspace dramatically increases it. Either attach it directly, or have an actively ventilated airspace.

The R-value of wood paneling is approximately 0.11 (m^2)*(dK)/(W) for a 1/4" sheet. where "m^2" is meters squared, "dK" is temperature difference in Kelvin, and "W" is Watts.

The R-value of the paneling on the outside of the freezer is approximately 0.05 (m^2)*(dK)/(W).

If we assume full heat dissipation to the atmosphere due to the natural convection (i.e. hot air rising as it passes by the condenser coil), the area of the side of the freezer where the coils are is 0.5 m^2 and that the condenser coils and surrounding air are at 311 Kelvin (100 F) and 294 Kelvin (70 F) respectively, we can calculate the heat transfer with and without the paneling using the equation:

W = [Area * (Thot - Tcold)] / Rvalue

Without paneling:

W =[0.5 * (311 - 294)] / 0.05
W = 170 Watts

With paneling:

W = [0.5 * (311 - 294)] / 0.16 (I use 0.16 because you add the two R-values, 0.05 + 0.11)
W = 53 Watts

So you are effectively decreasing your thermal transfer from your coils by 70%, therefore decreasing your efficiency 70%

Jester has the right idea because he is running a cooling fan to force air across the coils. This can also be accomplished by the stack effect. As long as the top and bottom are open to atmosphere, the air next to the coils will warm up and become less dense, i.e. lower pressure. This air will then rise out the top and be replaced by new cool air, which will warm up, become lower pressure and rise, over and over. This is how the chimney in your house works.

Jester is also correct in the fact that if you have stagnant air (top and bottom are closed from the atmosphere) you will have much lower efficiency for two reasons: 1) The stagnant air space next to the coils will warm up to a temperature just below the temperature of the coils and there will be very little heat transfer; 2) the stagnant air will transfer no heat convectively to the wood paneling further reducing the heat transfer.

Seems like a bad idea the more i think about it. I was thinking of instead of adhearing the strips directly to the freezer, framing out a whole wood framed box with a fan (maybe something a little more substantial than a computer fan) mounted on the bottom blowing air up.

Computer fans are pretty substantial. You can get them in the 70 – 80 cfm range for cheap. If your condenser coil area is 5 square feet with a 1 inch air gap, 70 cfm would completely replace the air in the space every 0.36 seconds! Much better than the stack effect. Plus they draw very little power so you can run them off a cheap low Wattage power supply.



Sorry to be such a poindexter but I ran into serious problems when I paneled an older freezer and I had to completely redo it, so I just want everyone to be properly informed so you don't repeat my mistake. Newer freezers are obviously much more efficient, to the point where they could probably handle the decrease in efficiency, but then you’re just throwing your money away in the form of a higher electric bill.

 

[Jester369]

Funny you responded, Jester. I was already reading your thread. That fan you mounted on the bottom, What kind of fan is it? Where did you get it? How much$$? How is it wired?

Also the coffin box on top. Did you just cut a hole in the lid with a sawzall the size of your coffin box? I was thinking of just cutting a approx 6" X 24" hole and not using a fan for circulation.

Really nice job on yours! I'm planning something very similiar.

I'll have to dig up the info on the fan. I know it came from McMaster, and I know it wasn't cheap, but it moves a LOT of air!

Somewhere in the build thread I have a picture detailing it, but no it's not cut the size of the coffin, I just cut two 2x2 holes at either end of the beer line chase. The beer lines go in one side, and if I ever get around to it, the cold air fan will go on the other side.

 

[firefly765]

The R-value of wood paneling is approximately 0.11 (m^2)*(dK)/(W) for a 1/4" sheet. where "m^2" is meters squared, "dK" is temperature difference in Kelvin, and "W" is Watts.

The R-value of the paneling on the outside of the freezer is approximately 0.05 (m^2)*(dK)/(W).

If we assume full heat dissipation to the atmosphere due to the natural convection (i.e. hot air rising as it passes by the condenser coil), the area of the side of the freezer where the coils are is 0.5 m^2 and that the condenser coils and surrounding air are at 311 Kelvin (100 F) and 294 Kelvin (70 F) respectively, we can calculate the heat transfer with and without the paneling using the equation:

W = [Area * (Thot - Tcold)] / Rvalue

Without paneling:

W =[0.5 * (311 - 294)] / 0.05
W = 170 Watts

With paneling:

W = [0.5 * (311 - 294)] / 0.16 (I use 0.16 because you add the two R-values, 0.05 + 0.11)
W = 53 Watts

So you are effectively decreasing your thermal transfer from your coils by 70%, therefore decreasing your efficiency 70%

Jester has the right idea because he is running a cooling fan to force air across the coils. This can also be accomplished by the stack effect. As long as the top and bottom are open to atmosphere, the air next to the coils will warm up and become less dense, i.e. lower pressure. This air will then rise out the top and be replaced by new cool air, which will warm up, become lower pressure and rise, over and over. This is how the chimney in your house works.

Jester is also correct in the fact that if you have stagnant air (top and bottom are closed from the atmosphere) you will have much lower efficiency for two reasons: 1) The stagnant air space next to the coils will warm up to a temperature just below the temperature of the coils and there will be very little heat transfer; 2) the stagnant air will transfer no heat convectively to the wood paneling further reducing the heat transfer.



Computer fans are pretty substantial. You can get them in the 70 – 80 cfm range for cheap. If your condenser coil area is 5 square feet with a 1 inch air gap, 70 cfm would completely replace the air in the space every 0.36 seconds! Much better than the stack effect. Plus they draw very little power so you can run them off a cheap low Wattage power supply.



Sorry to be such a poindexter but I ran into serious problems when I paneled an older freezer and I had to completely redo it, so I just want everyone to be properly informed so you don't repeat my mistake. Newer freezers are obviously much more efficient, to the point where they could probably handle the decrease in efficiency, but then you’re just throwing your money away in the form of a higher electric bill.

Thanks for all the science. Is a 80 cfm fan enough then. I'm planning framing out of 2x4's so i may have more space. I just bought the Fridgadare 7.2 today & found I have to swap out 2 pin lock kegs for 2 ball locks to make it fit. Can't wait to get started.

Another question: Using a low voltage power supply to power the fan, I've read just splice an old cell phone charger....right? Can i do the same with LED lights? any suggestions of a cheap LED option? Just looking for a cool glow to accent the Keezer tap area.

 

[Decypher]

Thanks for all the science. Is a 80 cfm fan enough then. I'm planning framing out of 2x4's so i may have more space. I just bought the Fridgadare 7.2 today & found I have to swap out 2 pin lock kegs for 2 ball locks to make it fit. Can't wait to get started.

Another question: Using a low voltage power supply to power the fan, I've read just splice an old cell phone charger....right? Can i do the same with LED lights? any suggestions of a cheap LED option? Just looking for a cool glow to accent the Keezer tap area.

Hey, no problem, glad I can finally put my engineering degree to work for something useful!

If you frame it out in 2x4s, even with a 4" air gap, an 80 cfm fan will still cycle the air every 1.25 seconds which is plenty.

I'm not sure about the cell phone charger. The one I have on my desk supplies 5V and computer fans draw 12V. You could try splicing it in and seeing if it will run, but you won't get 80 cfm out of it. If you can find a charger that supplies 12V, go for it. Just make sure that the charger can handle the amp load of the fan. As for LEDs, they draw 3.3V, so a phone charger would work great.

 

[firefly765]

Hey, no problem, glad I can finally put my engineering degree to work for something useful!

If you frame it out in 2x4s, even with a 4" air gap, an 80 cfm fan will still cycle the air every 1.25 seconds which is plenty.

I'm not sure about the cell phone charger. The one I have on my desk supplies 5V and computer fans draw 12V. You could try splicing it in and seeing if it will run, but you won't get 80 cfm out of it. If you can find a charger that supplies 12V, go for it. Just make sure that the charger can handle the amp load of the fan. As for LEDs, they draw 3.3V, so a phone charger would work great.

Thanks, any suggestions on LED's? Websites/brands/etc...

 

[firefly765]

Thanks, any suggestions on LED's? Websites/brands/etc...

I found these. They have 3 pin connectors. Can i just cut that wire & splice to cell charger?

http://www.coolerguys.com/840556014225.html

http://www.coolerguys.com/840556051763.html



And this runs off 115V. so i wouldn't have to bother with 12V adapter.....right?
http://www.coolerguys.com/840556069003.html

 

[Decypher]

I found these. They have 3 pin connectors. Can i just cut that wire & splice to cell charger?

http://www.coolerguys.com/840556014225.html

http://www.coolerguys.com/840556051763.html



And this runs off 115V. so i wouldn't have to bother with 12V adapter.....right?
http://www.coolerguys.com/840556069003.html

Yeah, give it a shot. Like I said, I don't know about the 5V supply with the 12V fan. The three pins on the fan are like this:

Red = +12V
Black = 0V (neutral)
Yellow = tachometer (you won't need this one)

If there's a fourth wire, it's for speed control, which you won't need either.

Dude, that 115V fan is GOLD! You are correct, that would eliminate the power supply. I didn't even know those things existed!

As far as suggestions for LEDs, I've bought from Super Bright LEDs and never received a dead one. Plus they have a really good selection. Always make sure to put a resistor in series with the LEDs when you wire them up, otherwise you'll run a very high risk of burning them prematurely. There's a couple of good calculators out there to find out what size resistor you need, I prefer this one.

If you're just looking for lighting accents, I would think that the LED rope that you can get at the hardware store would work pretty well. It's 120V so you wouldn't have to do any wiring.

 

[firefly765]

Yeah, give it a shot. Like I said, I don't know about the 5V supply with the 12V fan. The three pins on the fan are like this:

Red = +12V
Black = 0V (neutral)
Yellow = tachometer (you won't need this one)

If there's a fourth wire, it's for speed control, which you won't need either.

Dude, that 115V fan is GOLD! You are correct, that would eliminate the power supply. I didn't even know those things existed!

As far as suggestions for LEDs, I've bought from Super Bright LEDs and never received a dead one. Plus they have a really good selection. Always make sure to put a resistor in series with the LEDs when you wire them up, otherwise you'll run a very high risk of burning them prematurely. There's a couple of good calculators out there to find out what size resistor you need, I prefer this one.

If you're just looking for lighting accents, I would think that the LED rope that you can get at the hardware store would work pretty well. It's 120V so you wouldn't have to do any wiring.

Thanks, I don't even know what values to plug into that wizard.

I'm assuming if i have this fan:
Product Dimension: 80 x 80 x 25mm
Net Weight: 60g
Rated Voltage: 10.8~13.2VDC
Starting Voltage: 7VDC
Rated Current: 0.16A
Power Input: 1.92W
Fan Speed : 1800+/-10% R.P.M
Max. Air Flow: 21.71CFM
Noise: 20dB (A)
Bearing Type: Hydraulic Bearing

And I'm looking at this power supply in my hand:

input: 120V AC 60 Hz
Output: 6V DC 300mA

The fan would need 10.8-13.2 volts & my DC converter puts out 6 volts the fan would run about half speed. Thus, putting out around 10.5 CFM? If that's the case I think I'm good because my coffin box probably has about 1 Cu ft of air in it. I would exchange air about every 6 seconds....or am i way off?

 

[Decypher]

Thanks, I don't even know what values to plug into that wizard.

I'm assuming if i have this fan:
Product Dimension: 80 x 80 x 25mm
Net Weight: 60g
Rated Voltage: 10.8~13.2VDC
Starting Voltage: 7VDC
Rated Current: 0.16A
Power Input: 1.92W
Fan Speed : 1800+/-10% R.P.M
Max. Air Flow: 21.71CFM
Noise: 20dB (A)
Bearing Type: Hydraulic Bearing

And I'm looking at this power supply in my hand:

input: 120V AC 60 Hz
Output: 6V DC 300mA

The fan would need 10.8-13.2 volts & my DC converter puts out 6 volts the fan would run about half speed. Thus, putting out around 10.5 CFM? If that's the case I think I'm good because my coffin box probably has about 1 Cu ft of air in it. I would exchange air about every 6 seconds....or am i way off?

Hmmm.... not sure about that. The spec also says 7VDC starting voltage, so theoretically, your power supply won't reach that. If you have both in hand, I would say give it a try and see what happens.