Flow Diffuser in 500 gallon storage tank

[Medman]

I have been searching for this info, but I have not come up with anything workable.

I picked up my 500 gallon tank on Friday. The good news is that it already has a 1.25" port on the bottom and one near the top in the center of the tank. There are also a couple of 1" and 3/4" ports. No welder needed!
In order to maximize stratification, I would like to direct flow up to the top of the tank and diffuse it somewhat to reduce mixing. With the top fitting not on the top of the tank, what is the best way to introduce this diffuser in a 1.25" pipe so that flow is directed upward? How do I draw the hottest water from the tank?

I have a 1" and a 3/4" on the very top of the tank. Would it be better to manifold these two ports for charging/drawing heat?

I will try to get a pic up tonight.

 

[Nofossil]

That's a great question. If you're sticking with the fittings that you have as opposed to larger fittings, I think the best you can do is to make a round disk as large as possible (and still fit through the fitting) and weld it to a support rod so that it sits horizontal a few inches below the end of the pipe when the pipe is threaded in.

 

[DaveBP]

You might reserve one those ports in the top for an air separator. The smaller one would be more than ample.

Jebatty has an elbow of some sort in the top of his tank and uses the stock pipe ports, I believe. He'll probably spot this thread pretty soon.

 

[ewdudley]

I was planning on using a 2.0X1.5" double tapped bushing (in my case, you could use a 1.25X1.00) to insert a piece of pipe down into the top of the tank.

For the diffuser tube, tack a plate into the end of a short piece of the smaller diameter pipe, and then maybe use a cutoff grinder to put some slots in the sides to get a gentle flow out perpendicular to the pipe.

What a double-tapped bushing may look like:

http://www.oil-equip-mfg.com/docs/productsdoublebushings.html

Alternatively you might be able to get piece of thin-walled-greater-than-one-inch-ID piece of pipe or a piece of turned-down-to-fit 1.0" pips up into a 1.25" nipple and tack that in place, and then go ahead and cap it off and put slots in the sides.

--ewd

 

[Medman]

I'm thinking now that I will manifold the 3/4" and 1" fittings on the top of the tank, as they have the same area as one 1.25" fitting. I don't think that mixing will be as much of an issue using two ports to inject hot water. I will, of course, have an air vent at the top of the tank on the manifold.
I am going to use one of the ports on the side near the top for a sensor well for the 1-wire sensors.

 

[jebatty]

Jebatty has an elbow of some sort in the top of his tank and uses the stock pipe ports, I believe. He’ll probably spot this thread pretty soon.

Who would'a thunk I might see this! I assume the bottom fitting is at an end of the tank? Your situation may be different, but here goes. About 1/3 of the way from one end I have a top 1.5" (might be 1-1/4") fitting through which I fit a 1" supply line, 90 degree elbow with about a 6" horizontal extension pointed towards the far opposite end of the tank. The fitting extends about 2" into the tank. About 8" away in the opposite direction from the direction of supply flow, I have a dip-tube going to near bottom of the tank for the 1" cold water return. My tanks is 39" diameter x 19' long. With flows in the 2+ - 8+ gallon range (about a 90,000-140,000 btuh transfer rate), depending on return temp, I achieve extreme stratification on tank charging. For example, top of tank could be 170F and bottom of tank 120F (4 +/- gpm flow). And when the bottom of tank starts to rise, the rise is rapid, meaning the entire tank is reaching a full charge state. It is easy to achieve 185 top of tank and 165 bottom of tank by continuing charging, and I even have had the entire tank, top to bottom, at 192.

I don't draw water from the tank, as my tank is a radiator for my heated space. Interestingly, stratification is maintained during the cool down period, with at least a 30F temperature difference until the whole tank cools down. I don't see any reason why stratification would not continue with flows in a similar range during a draw down period, subject to return water being warmer than the bottom of tank water, depending on system return.

 

[Medman]

Yes, one of the fittings is on the bottom of the tank. It is at the end, on about a 20* angle from vertical.
How did you seal the 1" pipe inside the larger fitting after you inserted the elbow?

My tank is also 39" diameter, 10 feet long. I will charge into the top of the tank and draw from the top of the tank. My guess is that I will get some mixing when drawing from storage if the return is higher than the bottom of the tank, but I'm not really worried about it.