Paper on stratification.

[hkobus]

Over the summer I have looked at some storage options for my system. The following link I found very helpful in weighing my options.

http://www.preheat.org/fileadmin/pr...bo_Heat_storage_for_solar_heating_systems.pdf

Maybe others will post some more links here for all to use in the future. When I have some time this week-end I may post my plans for comments in a new topic.

Enjoy,

Henk.

 

[leaddog]

Thanks, when I get time I'm going to try and digest oll of this. Looks like some very good info.
leaddog

 

[Nofossil]

Good stuff. I built a Solvi style thermal stratifier into my tank - even invented it on my own. Would have saved some skull sweat if I'd known about the European research. In my case, I have a vertical manifold with a tap at the top and a tap at the tank midpoint. There is a coil that goes from the top tap around the tank a couple of times, connects to the lower tap, then continues around the tank a few more times to the bottom. The incoming hot water from the panel enters the manifold halfway between the taps. If it's cooler than the top of the tank, it will drop downwards and flow only through the bottom half of the coil. It actually works!

In this picture, you can just see the vertical manifold that acts as the stratifier near the bottom left corner. The top (closest) connection is the air ven. The top of the solar panel connects to the next connector about 12" lower. The solar coil is the rectangular coil made of 1" copper.

 

[hkobus]

Thanks, nofossil. I think I see what you did there. I am still organizing my thoughts on the whole thing, but leaning toward the plate HX to charge into fabric stratifiers. The flow in these things has to be low. Then I have a grudfos miximizer to drraw from the top of the tank and the return again through a stratifier(s). I am still pondering if there will be separate from the charge stratifiers.
That is where I am at at this point and still like to post the whole plan one of these days, just a bit busy with work yet.

 

[Nofossil]

Here's a data set from yesterday. My storage is hot since I built a fire Saturday to heat the hot tub after changing the water. Temps are in Centigrade, but for reference 70 is about 160 F and 65 is about 150 F.

Near the left, you can see all three storage temps take a slight drop. That's the morning showers pulling heat from the tank via the preheat coil. A bit later, the panel starts getting sunlight and starts to flow. Through most of the day, the panel outlet is at or below the temperature of the top of the tank. Therefore, most of the flow is from the panel through the bottom half of the tank only.

You can see that the bottom and middle of the tank gain heat while the top loses slightly. Not very impressive numbers this time of the year - the sun angles are not very good. However, I think that the stratification manifold is doing it's thing.