Control questions for storage

[huffdawg]

Do any forum members on here have a buffer tank for a primary loop. If so how do you control your storage circ with respects to boiler firing , charging storage and recovery from storage?

This is pretty much an exact replica of how my buffer tank and Storage are plumbed. Anyone have something similar? My Buffer tank is a 150gal. vertical propane tank my storage is 2 -500 gal vertical propane tanks.

 

[Bob Rohr]

A solar control with two delta T control outputs.

S1 greater than S2, pump powered by relay 1, valve is in spring closed position.
adjust ∆T on at 12 degrees, ∆T off at 8 degrees
you could also set a minimum temperature to start, maybe 130F?

To unload
S3 greater than S4, valve and pump are powered by relay 2, assuming the 4 way has a 120V motor attached?
same settings.

 

[Bob Rohr]

here is the manual for the Caleffi dual solar control. System Layout 2 is a dual delta T function, ignore the solar, the control doesn't know what it is connected to

You may play around with sensor location, maybe one top, the mate down lower or at the bottom so the entire tank would warm. Just push the sensors against the side of the tank under the insulation until you find the sweet spot.

http://www.houseneeds.com/upload/pdf/caleffi-isolarplus.pdf

 

[huffdawg]

here is the manual for the Caleffi dual solar control. System Layout 2 is a dual delta T function, ignore the solar, the control doesn't know what it is connected to

You may play around with sensor location, maybe one top, the mate down lower or at the bottom so the entire tank would warm. Just push the sensors against the side of the tank under the insulation until you find the sweet spot.

http://www.houseneeds.com/upload/pdf/caleffi-isolarplus.pdf

Sorry Bob I forgot to mention I will be controlling with the Vesta .Im just trying to figure out the best approach to control . I have 3 sensor wells in the buffer tank top middle and bottom ,same with the storage tanks.. By looking at my public display you can see how the rest of my system is laid out.

http://96.54.66.117/public/huff.html

Circs all ready controlled by Vesta are ..
-house demand circ
-house DHW circ
-shop floor circ
-Storage circ... set up with temperary rules
-4way valve.. motor removed from valve body till I figure out how to control...

 

[ewdudley]

Do any forum members on here have a buffer tank for a primary loop.

I control the flow of water from storage tank to the buffer tank with a sensor near the bottom of the buffer tank. This sets the minimum-return-to-storage-temperature.

A simple on-off function works quite well, e.g., pump on at 120 degF, pump off at 121 degF.

Ideally the minimum-return-to-storage-temperature would be controlled with an outdoor reset function, but I find that simply increasing the temperature from time-to-time as winter sets in and decreasing it likewise after Valentine's Day works just fine.

As a separate item, your radiant-floor zones should be drawing from the bottom of the buffer-tank/hydraulic separator and returning to the bottom of storage. This will send the coldest return water to storage where it belongs.

 

[velvetfoot]

I'm kind of new to the mixing valve concepts, but...

I can't understand the heat from storage logic. You're pushing water at the top of the 150 gallon buffer tank to the bottom of the big storage tank and then from the top of the big storage tank to the bottom of buffer. Isn't that moving hot to cold, and is that good? Maybe stratification doesn't mean that much for you on the buffer tank, but it is 150 gallons?

 

[huffdawg]

I'm kind of new to the mixing valve concepts, but...

I can't understand the heat from storage logic. You're pushing water at the top of the 150 gallon buffer tank to the bottom of the big storage tank and then from the top of the big storage tank to the bottom of buffer. Isn't that moving hot to cold, and is that good? Maybe stratification doesn't mean that much for you on the buffer tank, but it is 150 gallons?

The water from the buffer tank to the storage tank always comes from the top of the buffer tank.. the 4 way valve will direct either hot water to the top of storage or cold to the bottom of storage.. When buffer tank gets replenished with hot water it pulls the cold out of the top and pushes hot water from storage to the bottom of the buffer. Same as the drawing in post #1.. Thinking of repiping the storage circ in the off season , maybe pulling out the 4 way and installing another circ reversed beside the existing on. so that the flow will be top to top bottom to bottom.

 

[huffdawg]

As a separate item, your radiant-floor zones should be drawing from the bottom of the buffer-tank/hydraulic separator and returning to the bottom of storage. This will send the coldest return water to storage where it belongs.[/QUOTE]

I was curious about that when I put all the ports on the buffer tank.. might be able to modify that in the summer.