Co2 cylinder inside or outside your kegerator?

I'm in the process of building a kegerator for my home bar and am trying to decide if I should store my co2 cylinder in one of my bar cabinets and run gas lines to the kegerator or just store the cylinder inside the kegerator itself.

What is your preference and why?

I Put it outside so the reg works quicker, i seem to remember reading something about the diaphragm(?) responds slower due to colder temps.

Also i have 20# tank and it wont fit in fridge along with kegs due to sloped bottom.


General consensus is that it doesn't matter.

My thinking is this: If you have the space inside the fridge, put it inside as it prevents you from having to drill the fridge. If not, carefully drill a pilot hole and check for clearance before you make the hole bigger.

MC

Benefits to both. Mine are inside currently.

However, if you locate it inside and regularly open and close your kegerator the sudden changes in temperature can cause the CO2 to condense in the regulator, causing the regulator to "gunk" up. this will eventually require your regulator to need to be rebuilt as it will not be able to change pressures as easily and will turn much harder.

Outside, DANBY645BLS came with hole for the gas line and a mounted bracket to hold a 5Lb tank. It has wheels so I can roll it around.

I put a three way manifold inside. Not sure a tank would fit in there with 3 kegs.

I have my kegerator mounted on a wheeled board. The board extends behind the fridge to hold a 15 pound tank. I had no trouble drilling and grometting the gas lines. I do worry about the tank falling if I ever push the kegorator around. I need to build some sort of support, but haven't gotten around to it yet. I don't see a safe way to anchor a strap to the fridge. For me the biggest concern with keeping it outside the fridge is how to keep it from falling over and damaging something (e.g. the regulator).

I've done both. My kegerator came with a 5lb tank and a convenient bracket on the inside to hold it, so I kept everything inside.

Then I moved and the only CO2 place near my new house requires you get one of their 15lb tanks and swap out the empties for the new full one. The bigger tanks don't fit in my kegerator, so I had to drill a hole and run the line from the outside in. It works perfectly fine that way, though I was a bit nervous of hitting a refrigerant line when drilling.

Either way works just fine. I'd say go whichever way is easiest for you.

Outside the gauges are prone to rusting, can adjust pressures/change tank without opening the lid, and if you drill a small ole through the lid no worries of hitting a coil. Oh and it takes up space inside.

I've done both. My first keezer was 24 cu ft. Plenty of room. My second is 16 cu ft. I moved them outside to free up room.

My huge complaint about being inside was the inaccuracy of the bottle gauge. The child bottle showed pretty much the same pressure until it didn't. It would read full until it was empty. Then it was empty. I would be out of CO2 for a few days until I could get my bottle filed.

Now that it is outside, it accurately shows how full the bottle is. I also have a backup bottle, now, but that's beside the point.

Xtant said:

I've done both. My first keezer was 24 cu ft. Plenty of room. My second is 16 cu ft. I moved them outside to free up room.

My huge complaint about being inside was the inaccuracy of the bottle gauge. The child bottle showed pretty much the same pressure until it didn't. It would read full until it was empty. Then it was empty. I would be out of CO2 for a few days until I could get my bottle filed.

Now that it is outside, it accurately shows how full the bottle is. I also have a backup bottle, now, but that's beside the point.

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I'm not aware of a gas gauge that shows the level remaining in any liquid gas tank unless it is based on weight.

Not volume or a level. It's gas. Bottle pressure. There was very little change in bottle pressure until the bottle was empty.

Xtant said:

Now that it is outside, it accurately shows how full the bottle is.

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No, it doesn't.

Xtant said:

Not volume or a level. It's gas. Bottle pressure. There was very little change in bottle pressure until the bottle was empty.

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It's going to behave the same way with the tank stored at room temperature. The high pressure gauge reads the vapor pressure in the bottle, which will remain the same (assuming constant temperature) until all of the liquid CO2 is gone, and the tank is almost empty. As soon as the liquid CO2 is gone, the pressure will quickly drop to zero as the remaining vapors are used. No matter what temperature you store the tank at, the gauge has little to no relation to how much CO2 is in the tank.

The ONLY way to know how much CO2 you have in the tank is to weigh it.

JuanMoore said:

No, it doesn't.



It's going to behave the same way with the tank stored at room temperature. The high pressure gauge reads the vapor pressure in the bottle, which will remain the same (assuming constant temperature) until all of the liquid CO2 is gone, and the tank is almost empty. As soon as the liquid CO2 is gone, the pressure will quickly drop to zero as the remaining vapors are used. No matter what temperature you store the tank at, the gauge has little to no relation to how much CO2 is in the tank.

The ONLY way to know how much CO2 you have in the tank is to weigh it.

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I will admit that I took thermodynamics twice, but this is all wrong. As you fill a tank with CO2, the pressure inside increases because you are adding molecules into a fixed space. The more you add, the more compact you force them to be (ie, a larger pressure). As you use the CO2, that pressure decreases accordingly and that is how the empty/full gauge works.

If you change the temperature of your gas, it will drastically change the pressure. Even if you keep your CO2 tank at a constant cold temperature, that is not the pressure level that your gauge is set to show when it is getting low. In my mind, it would prematurely show an empty tank as cold gas takes up less volume than warmer gas. Regardless, I would not trust the high pressure gauge to determine how much is left in a tank when the tank is at a colder climate than intended. For this reason, homebrew stores are not allowed to fill your tank unless it is at room temperature so they do not risk over pressurizing it.

agslax said:

I will admit that I took thermodynamics twice, but this is all wrong. As you fill a tank with CO2, the pressure inside increases because you are adding molecules into a fixed space. The more you add, the more compact you force them to be (ie, a larger pressure). As you use the CO2, that pressure decreases accordingly and that is how the empty/full gauge works.

If you change the temperature of your gas, it will drastically change the pressure. Even if you keep your CO2 tank at a constant cold temperature, that is not the pressure level that your gauge is set to show when it is getting low. In my mind, it would prematurely show an empty tank as cold gas takes up less volume than warmer gas. Regardless, I would not trust the high pressure gauge to determine how much is left in a tank when the tank is at a colder climate than intended. For this reason, homebrew stores are not allowed to fill your tank unless it is at room temperature so they do not risk over pressurizing it.

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Yeah, no. Your description assumes a fixed ratio of gas:liquid. A 1/4 full tank and a full tank both have the same pressure (assuming equal temperature). I agree that a cold tank will have a lower vapor pressure than a warm tank, but what difference does that make? And the time difference between the two tanks (warm versus cold) after the liquid runs out is insignificant.

agslax said:

I will admit that I took thermodynamics twice, but this is all wrong. As you fill a tank with CO2, the pressure inside increases because you are adding molecules into a fixed space. The more you add, the more compact you force them to be (ie, a larger pressure). As you use the CO2, that pressure decreases accordingly and that is how the empty/full gauge works.

If you change the temperature of your gas, it will drastically change the pressure. Even if you keep your CO2 tank at a constant cold temperature, that is not the pressure level that your gauge is set to show when it is getting low. In my mind, it would prematurely show an empty tank as cold gas takes up less volume than warmer gas. Regardless, I would not trust the high pressure gauge to determine how much is left in a tank when the tank is at a colder climate than intended. For this reason, homebrew stores are not allowed to fill your tank unless it is at room temperature so they do not risk over pressurizing it.

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If the CO2 in the tank was all in gas form, you'd be correct, but most of it is in liquid form. If you took thermodynamics, you should know that most liquids are considered for all practical purposes to be incompressible. The vapor pressure of CO2 at any given temp is more or less a constant. Think of a recently filled tank, and let's imagine that the liquid CO2 takes up 80% of the volume of the tank, and above that is CO2 vapor. What's the pressure in the headspace? It's whatever the vapor pressure of CO2 is at that temperature. Now imagine the tank is nearly empty, with the liquid only taking up 5% of the tank volume. What's the pressure in the headspace? Just like before, it's the vapor pressure of CO2 at that temperature. So at constant temperature, the pressure will be constant as long as there's still liquid CO2 in there.

I'm simplifying things slightly above, but in general that's the way the tank pressure will behave. If you think it has any meaningful correlation to how full the tank is, you're mistaken.

you should always try to put you cylinder OUTSIDE the fridge for many reasons. I hit a coolant line building my kegerator, but I had it repaired. It can be done.

TD

Any tips to figuring out where the coolant lines run on the sides of a fridge?

I used our Fire Dept. Thermal imaging camera to find mine

I called my local fire station to see if they would come out and tic my fridge but for some reason they wouldn't.

TrickyDick said:

you should always try to put you cylinder OUTSIDE the fridge for many reasons. I hit a coolant line building my kegerator, but I had it repaired. It can be done.

TD

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what are those "many reasons"?

I asked the guy who installed my home draft beer system about this. This is all he does, install beer systems, has been doing it for 20 years. Once he started talking about it, he couldn't stop and I got tired of listening. I do remember some reasons. You can call him if you like and ask him, but he is a very busy guy. For one thing, its one less keg for you store in the fridge.
TD

TrickyDick said:

I do remember some reasons.
TD

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...and they are?????

agslax said:

For this reason, homebrew stores are not allowed to fill your tank unless it is at room temperature so they do not risk over pressurizing it.

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Actually most of the LHBS around here ask you to bring the tank in cold, so they can get the full 5lbs in. It is easier to get the gas in when the tank is cold. One new shop actually advertises that they will only charge you for 4lbs for a warm tank.

I'll ask Gary (the beer system guy) when he comes back. He still has to adjust the height of the secondary regulators mounted so kegs will clear. Maybe I'll take notes this time so I can remember what his reasons were as it seems I can't remember them after all. There was something about reading accurate pressures, and getting the carb levels correct, and something about benzene, but I'm not sure if the benzene thing was related to the tank temp or not...
TD

pabloj13 said:

Yeah, no. Your description assumes a fixed ratio of gas:liquid. A 1/4 full tank and a full tank both have the same pressure (assuming equal temperature). I agree that a cold tank will have a lower vapor pressure than a warm tank, but what difference does that make? And the time difference between the two tanks (warm versus cold) after the liquid runs out is insignificant.

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I completely neglected the liquid. I was just thinking of the gas state.

I still don't see why they put a full/empty gauge on the CO2 regulators like this one.

JeepDiver said:

Actually most of the LHBS around here ask you to bring the tank in cold, so they can get the full 5lbs in. It is easier to get the gas in when the tank is cold. One new shop actually advertises that they will only charge you for 4lbs for a warm tank.

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Weird, I might have to find another place to get filled. They would not fill mine up because it had been in my car too long.

agslax said:

Weird, I might have to find another place to get filled. They would not fill mine up because it had been in my car too long.

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If it had been in a hot car too long, and was too hot, then it makes sense that they wouldn't fill it. They would have had a hard time getting it full, and if it was really hot (100+ temps i.e. locked car in summer) then there would have been other issue with putting a really cold liquid in it.

It wasn't because it would have been overfilled.

agslax said:

I completely neglected the liquid. I was just thinking of the gas state.

I still don't see why they put a full/empty gauge on the CO2 regulators like this one.

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Well technically that gauge works (somewhat). It doesn't change at all as the liquid is depleted, but after that it does decrease into the "Order now" range as the remaining gas is depleted. Problem is, that time is so short that it makes the gauge completely worthless. They should make CO2 tank gauges like this:

pabloj13 said:

Well technically that gauge works (somewhat). It doesn't change at all as the liquid is depleted, but after that it does decrease into the "Order now" range as the remaining gas is depleted. Problem is, that time is so short that it makes the gauge completely worthless. They should make CO2 tank gauges like this:

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Hahaha, well done.

OK,

so Gary says that the big reason NOT to store your CO2 cylinder inside your kegerator, is that when your gauge reads empty, there is really still a third of the tank left, and when you go to exchange it, you are giving away a third of the tank full. Thus every three tank swaps, you're giving away a full tank worth of gas. Plus its one less keg you can fit.

TD

TrickyDick said:

OK,

so Gary says that the big reason NOT to store your CO2 cylinder inside your kegerator, is that when your gauge reads empty, there is really still a third of the tank left, and when you go to exchange it, you are giving away a third of the tank full. Thus every three tank swaps, you're giving away a full tank worth of gas. Plus its one less keg you can fit.

TD

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As I suspected, Gary doesn't understand basic fluid mechanics very well. If you go by the red "order gas" section on the gauge, it will likely tell you that you need a refill as soon as the tank cools to beer serving temps. If you let the needle go all the way to serving pressure or below, there will be more gas in a cold tank than a warm tank, but just barely, and certainly nowhere near 1/3 of a tank. The difference will be barely enough to serve a couple pints.

We use CO2 for welding here in Northern Ontario and the temperature doesnt effect the regulator at all. Nor does it effect the gas. The temps here can change 20-30 degree c in 12hrs.

I put mine in my keezer because it looks nicer and i disnt want to drill any extra holes.

Pressure x Volume = Universal Gas Constant x amount of moles of gas x Temperature

if the temperature decreases, like when you store a compressed gas cylinder in a kegerator, the pressure of the gas/liquid must decrease as well, as the cylinder volume is fixed.

I do not want this to degrade into a flame-war. basic science speaks for itself.

TD

TrickyDick said:

Pressure x Volume = Universal Gas Constant x amount of moles of gas x Temperature

if the temperature decreases, like when you store a compressed gas cylinder in a kegerator, the pressure of the gas/liquid must decrease as well, as the cylinder volume is fixed.

I do not want this to degrade into a flame-war. basic science speaks for itself.

TD

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Yeah, except most of the CO2 in the tank is in liquid form, not gas, and for all practical purposes liquids are considered incompressible, and are certainly not subject to the ideal gas law. The only time that applies is when all of the liquid CO2 is gone, and the tank is nearly empty. I already explained this to someone else just above your first post in this thread.

Mine is outside. I used the little adapter from Austin Homebrew to run the line through the wall of the kegerator. a 5 pounder could fit but I only own a 10 and 2 20s

Tricky is correct. But really the amount of change is so small it makes no real world difference.

Gary claims it's a third of the tank volume.

do as you will, I'm done arguing about where is the best place to keep your CO2..

peace out

TD

Mines on the inside I have a 20 lbs and two back up 5 lbs and good thing since I have a leak I can't find and keep running out! Need to figure out the leak, thinking about moving mine outside I have a wooden collar on mine so that's too easy. Also have the quick release system on mine as well

JDGator said:

Tricky is correct. But really the amount of change is so small it makes no real world difference.

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If he were correct that the ideal gas law could be applied, then the difference would be pretty significant. Luckily the ideal GAS law doesn't apply to liquids.

Geez...this thread brought back all my memories of two semesters of coffee fueled 7:30 am Thermo class. Peng-Robinson or get out!