best way to make a small water tank?
 

I want to make a DIY fresh cold water tap in my kitchen using one of those filter kits, but I'd like this water to come out cold. So what I'm thinking of doing is adding a bar fridge to the equation (I'd probably put it in the crawlspace) and in this fridge would be a holding tank. The water would pass through the filters outside the fridge, enter through a penetration I would make in the fridge, enter on the top of the tank, and another pipe with exit from the bottom and go up to the kitchen.

If not done properly this could be a huge disaster, is there any proper way to get something like this done? I need something that can withstand a constant 100PSI of pressure or so. I was thinking of using a length of 4 inch ABS pipe with two ends but not sure how to make the pipes enter/exit, and not sure if that is even designed for pressure application (thinking more about the glue joints). Also not sure if this would be rated for potable water applications given it's made for crap to flow on, not fresh water. :P

I'm thinking maybe an RV tank? Probably too big though... needs to fit in a small fridge.

What about if I make something out of copper pipe, think it would hold if I solder it well enough? I'd probably run an air pressure test overnight to check for any leaks after I've made it. I'm thinking I'd use some 4 inch copper pipe with two end caps, basically. I think I recall seeing copper drainage pipe at HD so it is available.

Look at kegerators - my RO system has a 3 gallon holding tank that would easily fit in most small kegerators.

Hmm never thought of that. Those tanks are metal so should be able to handle the constant water pressure. Not sure what kind of fittings they use, but I'm sure it can be adapted better then some makeshift soldered on fitting I had in mind.

It uses some plastic pex-like fittings but I'm sure you could adapt it for copper. I'm pretty happy with ours. We feed our fridge through it, as well as at the sink. The fridge chills the water, so if I want cold I can get it there.

or, another option
 

Considering the time, material cost and extra electricity cost might it just be easier to buy a new refrigerator that comes with a cold water filter??

However, if this is one of those thing where you want to do it to prove you can do it and challenge yourself, I completely understand.

If the crawlspace is either sand or dirt, why not take a 200' roll of 1/2 tubing and dig down about 4' in the ground, drop the roll in with each end above the ground...
Now you are using the ground to cool the water...

Don't forget to calculate the physics. For example, in a pipe with 100 psi, the cap is containing 1,256 lbs.

Red,

Replacing your current refrigerator with one that has a cold water dispenser would be the best (not cheapest) way.

If you still want to do it via your proposal, then maybe consider placing the on/off valve in the water line "before" it enters your mini-fridge. This way the tank in the fridge will not be pressurized. You could just use coiled up pex tubing in the fridge to hold the water which is how many refrigerators do it. Just have the outlet tubing higher than the water reservoir to prevent siphoning. Or you could buy a replacement plastic reservoir for a refrigerator and put that in your mini-fridge.

This set up would work the same as the cold water dispenser in all refrigerators except that you would use a manual on/off valve instead of an electric solenoid. Or you could get fancy and install an electric solenoid from a refrigerator and press a button to dispense the water.

EDIT: Or you could run a pex line into your current refrigerator, coil the pex line up inside to act as a reservoir and exit your refrigerator at a convenient point. Find a plastic box, like a shoe box, at a store and put the coiled up pex line in it to isolate the line from your normal food items. A refrigerator water dispenser solenoid and a push button would be much cheaper than buying a mini-fridge and there wouldn't be additional, ongoing expenses for electricity for a mini-fridge.

(Have to mention this: If you're not qualified to handle the electrical part, get a qualified friend to do it.)

HRG

I use a Brita pitcher/filter combo and just leave it in my fridge. After several hours the chlorine fizzles out and the water tastes great thru that filter.
http://www.brita.com/products/water-pitchers/classic/

Several hundred $$ later (for your materials etc) my water will taste the same and I did not have to go thru all the work you will. Must be the cheap Ukrainian in me.:yes:

Hmm so coiling would be acceptable? That is the easiest route. I don't even need any fittings inside the fridge, both ends can come out. Would I want to add a check valve before it enters the kitchen?

I have also thought of a new fridge but that's more then I want to invest, and I like the convenience of having it right at the sink.

The crawlspace is all cement and is conditioned space, so the fridge will just sit on the cement. I will install a receptacle in the ceiling to plug it in. The incoming water is rather cold to begin with, so it wont have to be in the fridge very long to get to a ice cold drinking temperature.

I actually have a brita but I don't really use it directly. I fill a big jug of water (which is a long process, can only do a bit at a time) then put the jug in the fridge. If I put the brita in the fridge I find the water taste funny... I order pizza a lot. :whistling2: It picks up various tastes from inside the fridge.

Is that really how it works? I figured the energy was just spread across the surface. So 100PSI on a 2 inch cap would actually be 50 pounds per inch (but 100 total on that entire surface). Well I'm thinking in 2D and not 3D but you get the idea.

Just out of curiosity Red. Why such a high psi, 100, at your fridge? Do all your fixtures get that amount of pressure?

I'm just guessing, never measured the exact pressure. Could be lower or higher, but think I recall it being around there. Of course it depends on where in the city etc.

Sorry; didn't mean to confuse anything. But, using a 4" cap as an example, the area of that cap is the radius squared times pi, or 12.56 square inches. Multiply that times 100 pounds per square inch, and you have 1,256 pounds against that cap. So, my point was, and I don't know the answer off the top of my head, will a schedule 40 threaded or glued cap, again, just as an example, contain that pressure? Or do you need something heavier? This is the reason that most compressed air tanks have rounded ends, as opposed to what would be simpler and less costly flat ends.

Yup, coiled tubing is how some refrigerators provide a reservoir for their cold water dispenser. Here's an example of a coil type reservoir that sells for $13.20:

http://www.rcappliancepartsimages.co...0/00890471.jpg
And a link to the item:
http://www.repairclinic.com/PartDeta...ntainer/962383

Refrigerators don't have a check valve in their water dispensers. They just have the tubing from the dispenser solenoid run to the reservoir (tank or coiled tubing) in the food side. The output tubing is run to the door on the freezer and ends up at the water dispenser spout. The tubing in the freezer door is not cooled so that does cause the first few seconds of water to be warm until the cold water from the reservoir exits the dispenser spout.

HRG