Be part of our community & join our international next generation forum now!
Can we talk about this a bit more?
What are some specs for a pump for example?
Pipe diameter?
Would a hot water recirculated pump work?
Etc.
StillDragon North America - Your StillDragon® Distributor for North America
Comments
I use standard plumbing household supplies recirculation pumps. Bronze fittings all of my piping is 1" Heavy wall PVC rated for 110deg hot water piping.
I run 1 1/4 lines, the recirculation pump is a high efficiency boiler recirc pump.
I have both Grundfos Alpha and a Taco circulator - both have displays. I want to say they usually run about 15 watts.
Rpms on those pumps @grim and @DonMateo?
StillDragon North America - Your StillDragon® Distributor for North America
No idea, they are variable speed pumps. I can select low/medium/high speed, or run 'constant pressure' that varies the flow rate. They can read flow rate or watts consumed while running.
They use such little power it's silly.
Does the Grundfos model look like this?
StillDragon North America - Your StillDragon® Distributor for North America
No has a display and digital controls - Grundfos Alpha 1.
I think both of the ones I've got have been replaced with newer, fancier models.
Grundfos Announces New UPSe and Digital ALPHA Circulators @ PR Newswire
The main consideration is, these are not pressure pumps, they are circulators. Ideally, you aren't pumping water through narrow piping, tons of bends, crazy vertical lifts. They've got about 20 ft head.
In all my control schemes, I don't restrict flow, I simply bypass the flow I don't need, or run full flow, and use mixing to target the coolant temp I want (hotter or colder).
Yep, I hear what you are saying and totally get the theory.
Just trying to sharpen my practical understanding so that I can recommend and draw a practical diagram for a customer with less than optimal cooling capabilities.
StillDragon North America - Your StillDragon® Distributor for North America
One of the issues with these circulators is that unless you are getting the ones with stainless heads, they'll rust and discolor the coolant. Stainless heads are available, but start to get prohibitively expensive.
On the plus side, these things are bombproof, they are intended to run in far more demanding conditions (hot water heating), for decades. Slinging some cooling water for a few hours a week isn't a big deal.
Look right?
StillDragon North America - Your StillDragon® Distributor for North America
Yeah - assuming those valves are manual control?
Keep in mind, higher the input flow rate, the higher you want to dial up that recirculation flow rate.
you use any boiler additive? or adjust pH to slightly above 7.0?
No additives. I've always been a bit hesitant to do it, for fear of a pinhole leak in the condensers leaking any kind of additive into the product.
The still condenser cooling loops are straight water. I do dump and refill every few weeks. Aside from some rusty discoloration in the water, the pumps are all working just fine - 7 years or so later.
I'll tell you, I can get longer periods before dumping if I end up treating it more like a pond than a cooling tank. Don't let the temps get too high, or too cold, keep it open to the air. Ignore the light algae that grows on the inside of the tank walls, they are doing their job to keep the water clean.
Nuking the cooling tanks by letting them get very hot - you end up killing off the algae and have to dump the tanks.
Keeping the thing sealed to air (I can close off the tanks entirely) - they tend to get very stagnant very fast.
Doing both of the above - you end up with h2s formation and bad bacteria. The only way I got that to work long term is by dosing the tank with sanitizer (quat) or running an ozone injection.
I kept the pumps running once for a few weeks straight - that actually tended to work the best for keeping the tank smelling fresh and clean - I'd imagine kind of like a fish tank.
Very hot @grim? How hot would you imagine is too hot?
So interesting how treating the thing more like a pond gives you better service life out of your water.
A plant derived grey water reactor system (or the like) comes to mind.
StillDragon North America - Your StillDragon® Distributor for North America
Seen a little 3 speed pump on Amazon with a SS impeller for 89 bux. Seems like a pretty good value?
StillDragon North America - Your StillDragon® Distributor for North America
Yeah, that's perfectly fine. You could consider locating that pump at the lowest level of the recirculation pipeline, as opposed to on the riser pipe, since these pumps have no ability to self-prime. Maybe a tiny bit of insurance against it dry running.
Good call. An air bubble might shorten the service life.
StillDragon North America - Your StillDragon® Distributor for North America
@Bolverk
StillDragon North America - Your StillDragon® Distributor for North America
Is this the original post? Dephlegmator With 3 x Inputs And 3 x Outputs - How To Plumb It?
I can't remember? I think there is one more post where by @grim does a nice job of illustrating the concept? Not sure which came first?
StillDragon North America - Your StillDragon® Distributor for North America
Not sure, but that was a good read, thanks
I still run that recirc approach on the dephleg, it's the winning model for large dephleg systems, especially where you have high variability in input water feed temps (winter/summer, chiller & reservoir systems, etc).
Tempering dephleg coolant by passing it through the product condenser first is great, but it links those two systems together.
Well, I'm sold. I'll be welding 2 threaded bungs on my 4" dephleg for an upcoming project