Another storage mixing question for you well instrumented folks...

[kuribo]

For those with tank temps available top and bottom of your storage tanks, have you noticed what happens to your stratification while the tanks are being loaded by your boiler? For example, assuming you let the tank temp drop to say 100F top and bottom, when the boiler fires and starts to recharge the tank, do you see the top temp rise and the bottom temp stay at 100F, or does the flow in and out of the tanks mix the water inside such that your bottom of the tank temps rise as well? If so, how much?

Trying to get handle on how well storage tanks stay stratified with charging.

Thanks for any and all replies.

 

[maple1]

My top temp rises, bottom stays.

Think of a horizontal line inside the tanks. When depleted the line is at the top. Start adding hot water into the top (160 here) and it pushes the line down as it comes in. Above the line is 160, below is depleted (120?). When the line gets to the bottom, that's the end of lap one then it resets to the top with 180 being above the line for lap 2.

 

[kuribo]

Ok, so you are seeing good stratification even while/during loading, rather than mixing while loading and stratification once the flow into the tank from the boiler stops....Thanks!

 

[warno]

My storage is three 250 gallon tanks stacked horizontal. They stratisfy fine while using heat loads but during charging I move enough water through the stack that the temps balance out and they climb together in temps. From top to bottom it's within a few degrees while charging.

 

[kuribo]

My storage is three 250 gallon tanks stacked horizontal. They stratisfy fine while using heat loads but during charging I move enough water through the stack that the temps balance out and they climb together in temps. From top to bottom it's within a few degrees while charging.

How many gpms you moving? Are you following best practices for plumbing/filling? (large headers, flow entering horizontally, flow velocities less than 2 ft/sec, diffusers in the tank, 2 pipe tank plumbing)???

 

[warno]

My headers are 3" pipe with 1" connections coming from them for loads and the FPHX for charging.

I'm moving around 20 gpm while charging. Since I've been running this season, after redoing my plumbing, I haven't had any problems. As soon as the fire goes out and tanks are charged everything starts to settle out, as it should.

Here's the stack.

Here's the supply header.

And here's the return header.

 

[kuribo]

My headers are 3" pipe with 1" connections coming from them for loads and the FPHX for charging.

I'm moving around 20 gpm while charging. Since I've been running this season, after redoing my plumbing, I haven't had any problems. As soon as the fire goes out and tanks are charged everything starts to settle out, as it should.

Here's the stack.

Wow, that's some fine welding on those headers!

I think you are getting mixing because of the large flow rates, though your flow velocities of around 1 ft/sec are certainly within the recommended amount...20 gpm into and out is bound to lead to mixing....

Thanks for the info, much appreciated!

 

[maple1]

Ya, mine are nowhere near that much. Not sure exactly what they are but the loading unit circ is a 15-58, on low speed. And mixing on the first lap.