What is the best value 80-100 gallon tank for storage/buffering?

BigRob

I don't need a stainless tank and don't want to break the bank. The American Water Heater SE62-119R-045S looks ok:



<a href="http://www.americanwaterheater.com/products/pdf/lsst10.pdf">http://www.americanwaterheater.com/products/pdf/lsst10.pdf</a>



I was originally thinking I did not want a heat exchanger, although I'm thinking it's not a big deal to add an expansion tank now. There must be other "go-to" options. Let me know what you think!

Steamfitter66

Depends

on the application. Boiler, solar, Geo and whats the btu load and device output?

BigRob

Solar/boiler

Hi Steam, the tank will buffer a radiator micro load of about 5000btu/h and store energy captured from solar through an external heat exchanger elsewhere in the system.

Steamfitter66

I dont do solar

as its not really cost effective in IL, but there's nothing wrong with American.

Mark Eatherton

Beware the bushing effect….

Any time you are pushing water out of a pipe and into a static (relatively so) tank, there is a condition called the bushing effect which can create a whole lot of resistance. The smaller the tapping, the higher the velocity, the greater the effect…



Cheap electric tanks as buffer tanks aren't always such a good deal.



Just sayin'…



ME

Steamfitter66

May not apply

I believe this tank is designed for solar and has 1" tapings.

I think what you are talking about is the turbulence caused by the hi velocity discharge entering the relatively stagnant water. Its compounded when using reducers right at the tank without sufficient length of straight pipe to smooth out the flow.

PLUMMER

Interesting bit of info

Mark could you elaborate on this bushing effect and problems? Link maybe....My searching didn't reveal to much.

BigRob

3/4 nipples

I have noticed most of the solar tanks and electric water heaters have 3/4 nipples and the nipples are not in the best locations. I'd like 2 nipples low and two nipples on the top of the tank.

Steamfitter66

look at the cut sheet

It has both

BigRob

Right

..The American Water Heater tank does. Can anybody recommend any other manufacturers?

hot_rod

if you need large ports

the ThermoCon has seven 2" ports arranged around 3 sides, and a few 3/4" on top. This is a heavy steel walled tank with a thick glass lining, and a 21 gauge jacket, as you can see by the weight of the tanks. A quality US built tank designed to last.



I do work for Caleffi, so I am biased.



Boiler Buddy is another good brand of buffer tanks. They are not glass lined and have a 75 psi pressure rating.

Steamfitter66

I think this may be

the most cost effective tank available. I think AO smith only has one with a HX. they are are less than 800

BigRob

Solid Tank

Caleffi is my favorite hydronic brand and this tank is super flexible. It's lowest internet price for the 120 gallon is only a couple hundred more than the next best I found:



http://s3.pexsupply.com/product_files/TJV-120M-Overview.pdf



I especially like the 25 gallon, although it's really expensive on the internet. I would for sure have used it a while back if I had known about it.

Mark Eatherton

Old books...

Quite honestly, I am not even sure I still have the book that taught it to me, but it does make sense.



If you want to test the theory, take a 5 gallon bucket of water, and place a running hose into the bucket. The effect is obvious and immediate. It has to do with velocity and the creation and compounding of eddie currents.



It's just one of those things you place in the back of your brain, and it automatically bubbles back to the top when needed :-)



ME

PLUMMER

Hmmmm

Thanks Mark appreciate the bit. So its a disturbance in the start layers that causes the problem if I got that right. I did several more searches and not one bit came up, so thanks for the valuable tip.

So would you think an 1.25" copper supply to a 1" tap from a 007 or equivalent might be an issue? Older cast iron boiler. Since this is where I find the most over sizing problems, not so or so much with mod cons.

Most of what I come across in SE Michigan is a 100-160kbtu stuck in a 22-40kbtu HL house. 1-4 zones at most with anyone needing 6gpm at most. Lots of smaller houses here with lots of updating. And making n existing system more efficient is pretty easy , when you have to work with the old way they used to install. Short of a new proper size boiler, the controls and buffer tank are the most expensive parts.

BigRob

Makes sense

As the pipe diameter decreases while gpm stays constant, the velocity increases and the tank just looks like a target and the water a projectile. There are equivalent lengths for pipes entering a large expansion. I read you have to taper the pipe into a tank.

Steamfitter66

The more water you disturb the more energy you use

A pipe nipple same size as the opening at least 6x pipe diameter if over 4 fps. The more turbulent the flow at the at the vessel tapping the more energy is absorbed moving water in the tank.