Need help with plumbing new storage

warno

Or would something like this be better with separate heat source and load manifolds?

hot_rod

Are you modifying "off the shelf" tanks or building your own? That drawing would take a lot of connections into the tank, a lot of welding.

Using balance valves eliminates the needful reverse return piping and some pipe and fitting complexity

I like the Hybrid parallel/ series, large pipe size connections between tank best, cleaner, less connections.

There are a number of ways of piping tanks together, they all work well, it depends on which is best for you to build.

Ideally one large tank is best to eliminate large surface area and heat loss, complex insulation details at all the connection points, etc.

Multiple tanks are used if you need to get thru a door opening, or have access to them at a good price. Large 500 G or more LP tanks can be modified inexpensively if a one tank option is possible.

One large tank give you storage, hydraulic separation, and the top portion could serve as your expansion space or "vessel".
A single tank allows for best temperature stacking, as you pump through multiple tanks you lose some of that stratification potential.

warno

I'm using decommissioned propane tanks for my storage, it will be 3 of them at 250 gallons each. I plan to build legs on them to put them vertical. I can get these tanks for dirt cheap which is why I'm going this route. They are going in my garage and I don't have a ton of realestate to give up which is again why I'm going with 3 small tanks. I've been ASME certified in welding for about 10 years now so all that labor I'm doing myself. I know I'll have parts in it but the time in welding is nothing to me.

So are you telling me I should stop trying to over complicate things and go with my original idea of a single supply and return manifold on my tanks? If that is the case I just need to know where to put my plain steel expansion tank plumbing. I'm curious why the very tops of my tanks wouldn't work to tie my expansion into? If I build a header pipe that all tanks attached to then run my expansion line from that would this not work?

hot_rod

Gosh, if you are a welder and can weld leak proof connections you have a lot of options.

What you are trying to do is create one large storage vessel with those tanks. Do that with the least amount of piping, connections, labor and leak potential.

Weld 2" nipples into the tanks and build that 3 tank hybrid arrangement. If you can line everything EXACT union the tanks together. Or have some short flexes built, like this 2", these can be build with any fitting configuration, maybe union x union would be simple to connect onto welded nipples in the tank?

Here is how I have my 500 lp tank.

3" headers into top and bottom. Slots cut on the header inside the tank assures slow even flow with minimize mixing.

The large pipe size headers become your hydro separator. So you can pipe all your connections from the header. Some pumps are flowing away from the bottom header, some are flowing into it. The large headed assures all pumps get along, regardless of flow rate or direction, primary secondary piping essentially.
Add mixing devices for low temperature zones.

As you see on my tanks the solar DB, which is a Grundfos Alpha in delta P mode, high flow to start, tapers off to exact gpm when siphon establishes, pumps away from the bottom.

Circ pumps for all the loads are pushing into return, suppling loads from the top hot header.

The back up Lochinvar boiler connects up high heating only about 35 gallons of the tank. size that connection for the amount of buffer "tank" you need.

I have not tried to capture a bubble for expansion in multiple tanks, but I think it would work, and eliminate that expansion tank up high. The key is how you remove air. Once I purged all my zones, lots of Webstone valves! the sight glass assured I had enough air "space" at the top for my expansion bubble. 3/4 Uponor pex is the sight tube to see that level.

I've been running a month or so on this tank, mostly wood input, today solar is running 6 gpm into the tank. Previous to this 500 tank, I had 160 gallon running like this for several years.

For loads I have:
Several cast radiators with TRV, on the Armstrong delta P circ.

Wood boiler on the Taco Viridian, it will run delta T, once I figure out how to program the thing, it runs a 140F on right now.

HW coil in my heat pump.
DHW via flat plate, flow switch triggers that pump.
Yet to be added a mixed circuit for my slab radiant with ODR.

The system is filled with water, a HX could be added if you want to glycol your underground loop.

One fluid circulates in the tank, solar, radiant, radiators, etc, all at 10 psi.

My system is a test bed as well as my shop/ office heat and DHW. I piped it with insulated stainless flex to allow me to easily swap out components and make changes, not the prettiest looking assembly

warno

To get the tanks in my garage I have to keep them separate but once in the garage I was going to weld bracing between them all to make it one piece then weld my plumbing directly to them.

I planned for my manifolds to be 1.5" then stepped down to 1/2" at the last tank in the run. There will only be 2) 1" lines pulling from the manifold for heating. The HX line will be pulling from the return manifold feeding into the supply manifold, so if a heat load kicks on it will pull right from the "fresh" supply of hot water while charging tanks. And when not charging heat loads will pull from the storage water.

I really don't mind the expansion up high. It will be in the rafters out of the way. I just want to make sure I get it plumbed in right so I'm not getting air back in the system.

hot_rod

This should work.

Pump into the boiler pulling thru the 3 way mix/ protection valve.

P1 would turn on when the boiler is 140F or higher, some boilers have a switch for that on the control. I use a solar control for mine which varies the speed as temperature rises it speeds up. It has a low limit set at 140F, so it only pumps when the boiler is hot, a second form of boiler protection.

P2 is the pump from the HX to the tanks. It could run on a delta T function, also from a solar controller. So whenever the boiler is warmer than the tanks it loads into the tank. Say 10F on, 6° off, pump run when boiler is 10° warmer than tank, shuts down when tank is within 6° of boiler, adjust either number to your desire.

Assume your boiler is a 100,000 output. P2 moves 10 gpm into the tank.
If a 2 gpm load calls from wherever, 8 gpm goes into the tank, 2 gpm to that load. Any combination of gpms is possible with the large separator/ header.

When the tank reaches high limit temperature P2 shuts down and the zone pumps, garage and house line, pull 100% from the tanks.

The separator in the house works the same way, any combination of load gpms pulls from it, put as many loads off that as the sep size will allow, size it for 10 gpm also.

If the tanks are connected with a large pipe size, 1-1/2 or 2", and the header is sized large, then that entire assemble becomes the PONPC, tie the expansion tank in anywhere on that assembly.

Keep in mind when you use a tank without a diaphragm or bladder it needs to be much larger, don't use the 10% rule of thumb. Here is an example and the link to the Wessel tank sizer.

650 gallons total, 55°- 185° operating temperature, 12 psi fill, max. 26 psi
http://westank.com/calculator/

warno

My boiler will be shut down by a flue sensor so once my flue gets down to around 220 degrees it will shut everything down as far as charging tanks go. And my boiler holds heat for long enough that by the time the next fire is lite it should still be over 150 degrees.

I think I'm going to work up another drawing now. I appreciate all the help, thank you very much.

warno

I redid my drawing, basically copied hot rod's drawing, but I do have one question. I redid my expansion tank estimate again and it turns out I need alot more then o thought. Hot rod was right I need close to 120 gallons with a plain steel tank. I have room in the garage attic for a couple of smaller tanks but that's alot of weight to hang in the rafters? How much water will actually expand up in there?

If I put my expansion tank on the floor next to my storage tanks how can I plumb this in? Will this even work?

I decided to go with a supply and return style manifold in the house and I believe I will need to zone with circulators because the length of run to the house and the future zones in the home.

hot_rod

p3 and P5 are pumps in series, depending on the load and zones you are connecting one pump may work fine, then add zone valves for additional loads at the he house manifold

If you want various temperatures at the house manifold, a seperator would give you the ability to disconnect the P3 from any distribution zoning and mixing stations.
A separator would also provide additional air, dirt, magnetic separation. So P3 pumps into one side of the sep, distribution from the opposite side.

A Caleffi Hydrolink is great for that device, it give you a separator and manifold in one box

Everything else looks fine

warno

Looking at the Caleffi hydrolink ADF fIle, I'm pretty confident I could build something very similar to the hydrolink. So if that's the only thing missing from my drawing in can move forward with this project finally. Lol

Thank you very much for all the help and advice.

hot_rod

Sure, with your skills you could weld up exactly what you need. Looking over the cut away drawings gives you an idea of what is under the hood.

Not all factory built hydraulic separators, or low loss headers are built equally, here is the key to assuring that the do the job. 3:1 ratio, very low flow velocity in the barrel.

http://www.caleffi.com/sites/default/files/coll_attach_file/idronics_15_na.pdf

The Hydrolink is both a header and separator device, if starting from scratch there are a few tweaks I make on that device.

The small separation chamber in the Hydrolink limits it's flow rate, better air removal could be built in, this info should show you the concepts and get you thinking.

warno

That's the pdf I found as well. I'll see what I can come up with. Thanks for the info.

warno

So with my plumbing pretty well pinned down I have another question.

How close can the bottoms of my tanks be to concrete floor? I know I need insulation under them but, how much would be considered minimum?

warno

So I'm dragging this thread back up again since I've started working on this project again.

I'm back with a question of plumbing my expansion tank.

I've realized I simply cannot put my expansion tank up in the rafters of my garage, it's simply to much weight for their design. So my only option is on the floor next to my storage tanks.

Is there any way to plumb my plain steel expansion on the same level as my storage and not get air back into my system?

I also changed my orientation on my storage tanks. I'm going with the 3) 250 gallon tanks stacked horizontal one on top the other 3 high.

warno

I've been doing more thinking, probably a dumb question but if my expansion tank is put in the floor right next to my storage and I tie into it at the bottom. Could I purge the air from the air bubble over the water and replace it with helium or argon? Would these gasses get absorbed into the water like air will?

hot_rod

why not leave an air space in the upper stacked tank? No need to add another tank to the system if you can give up some of the upper tank.

I have solar, wood boiler, and LP boiler feeding into my tank, radiant and DHW zones come off it also.

warno

I was wondering about that too. Do I just assume the same expansion volume as a normal compression tank?

hot_rod

Wessels has a sizer program for both diaphragm and non diaphragm style compression tanks. Once you determine the required air space, calculate that out of your upper tank.
http://westank.com/calculator/

Or I have a couple large expansion tanks that I would like to unload B&G brand, HFT 90V

warno

On the expansion calculator I found it said I need about 100 gallons of plain steel tank.

On that drawing it shows "air return tube", is that coming from an air scoop or something? Does it bring any air that gets drawn into the system back to the bubble?

hot_rod

It's not a bad idea to put a discharge on the air sep and route it to that air space

Usually the compression style tanks are about 3 times the size of the bladder or diaphragm style, size it both ways to compare

warno

I'll be using used propane tanks as my expansion tank.

I'm wondering about plumbing multiple tanks together in a chain. I plan to lay the tanks on their side and then hole saw 1" holes in the face of the ends top and bottom. Then weld 1" pipes to connect each tank to the next. Then tap an airtrol fitting into the first tank. I'm thinking this will act as one long tank. Am I thinking right it wrong here.


I plan to chain them together Like in my attached pic.

hot_rod

I can't say I have ever tried that. I don't know that you need to connect in two places, tank to tank ?

With bladder or diaphragm tanks we just header together at one connection point, top or bottom on base mounted style.

warno

My thinking was with a pipe top and bottom, the tanks would act as one long tank and balance the water level between themselves. With the air balancing on top and the water balancing on bottom.

hot_rod

The LP tanks probably already have a few side taps, why not just header them together across the bottom? Typically there is a 1/2" or 3/4 tap for a gauge and relief valve. The fill port is typically 1" and you have a 4 bolt flange connection for the float- level indicator. You have more "holes" than you need already

Save the drilling and welding. The air will rise to the top of both tanks, just fine.

warno

The tanks I have for my expansion are the large vertical "grill" style tanks. They only have the one 3/4" fitting in the top for the on/off valve.

hot_rod

warno said:

The tanks I have for my expansion are the large vertical "grill" style tanks. They only have the one 3/4" fitting in the top for the on/off valve.

Flip them upside down, remove the valves and header them together.

Getting the smell out of former LP tanks can be a painful experience. Washing multiple times with Oxyclean can help.

Occasionally you may need to add to the air space, add a drain valve and a tee with a Schrader valve to allow that process.

warno

Yeah I hear ya on the smell, I have washed out 3) 250 gallon tanks that are going to be my storage tanks. I found that a lot of dawn dish soap and a hotsy pressure washer do wonders. Had all the fittings removed and went to town with the hot water filed it about half full then took it out back and dumped it. Smelled to high heaven but after letting it sit upside down in the baking sun for 2 months after washing it really wasnt too bad. The oil seems to really hold the stink in these tanks so if a guy can get that out it helps tremendously.

I have been thinking of that drawing that's shows the air cushion in the storage tank. Isn't that how your system is currently? If so how well is it working? Do you notice any air problems anywhere?

Ive been contemplating putting my 2) 25 gallon tanks in the rafters of the garage, since they don't weigh much, and having the remaining air cushion in my storage tank. Then trying to math it right so that once expanded the storage will be full of water and the air cushion is in the tanks in the rafters. Could this work?

Thank you by the way for all the advice. I know I go back and forth alot and may be hard to follow but I do appreciate the help.

hot_rod

well I have never tried that method, but I don't see why it would not work.

Is it that you don't want to give up the capacity to capture the air bubble in the stacked storage tank bundle? I'm not sure keep air in multiple tanks and places has advantages?

I ran a vertical mounted 160 LP tank with an air bubble up top for 3 years, this spring I switched to a 500 gallon with a few different features and more capacity for storage. I don't have a lot of heating hours on the new setup, with wood boiler or LP input, but it runs every sunny day as a drainback solar, providing 100% DHW.

My goal on this version was to use sparge tubes to help stratification, use a plate HX for DHW on demand, buffer the wood boiler and solar array, and tie the LP boiler to the very top, maybe 35 gallons of tank space. All indications are that it will work fine.

I also use a piece or 3/4 Uponor pex as a level tube,sight glass up top to keep an eye on that air space as it runs thru temperature swings.

I ran the math to get enough air space and still use as much tank capacity for thermal storage, placing the upper spare tube was critical.

warno

Yes, I don't want to give up capacity. I just wanted to keep as much water in the storage tanks as possible. I already have the 2 small LP tanks to use as expansion. so I figured I could just stuff them up in the rafters to hold the air bubble and then the storage tanks could remain completely or almost completely full. Is there any reason not to use the other tanks in unison with the air bubble in the storage? Future problems with it?

I could easily put in a sight tube for water level checks that's not a problem.

warno

Here is what I was thinking for my storage design. 3 tanks stacked horizontal with 2" connection pipes between them on opposite ends, and a 3" manifold in the bottom tank and in the top tank a 2" zone manifold and a 1" return from plate HX. The 3" lower manifold will extend down the length of lower tank to make the circulation work right. The air bubble will be in the top tank.

Here's a pic of my drawing

warno

Hey hot rod calling on your help again.

In that drawing you posted, what is the part with the "air return tube" coming from it?

hot_rod

If you put any sort of air purger on the distribution piping, or elsewhere, you need to put that evacuated air back to the "air space" bubble at the top of the tank.

When the water cools if can reabsorb that air, then get vented out when it heats up again.

Over time you vent out all of your air bubble, lose expansion space and eliminate drawback solar function.

That assumes a fill valve replaces that evacuate air with water.

If you just evacuate the air, no fill valve to re-pressurize, then the pressure may drop to zero.

That was one of the functions of the B&G Airtrol fitting, put the air purged from the boiler up into the compression tank. With the older cast iron boiler with air removal areas built in, that was sufficient air elimination.

With modern small HX tube boilers, micro bubble removers serve a better purpose.

Caleffi has a fitting to convert that metric thread to a 1/4 NPT thread to make adding a vent tube easy. 1/4 copper tube is all you need.




You want 5 psi at the highest point in your piping, ideally.
If the boiler relief setting allows, and you have enough expansion space, run higher pressure. Higher pressure increases the boiling point if you add solar collectors to the loop.

warno

Does that "air bubble" and air separator still work without the solar loop in the system? My storage will only be heated from my boiler via a plate heat exchanger. I don't have any solar in my system.

hot_rod

Still works, solar or not.

warno

Ok thank you for all the help.

Last question to be sure, if I run the taco air scoop with the air vent on top of the scoop, where in the system is best for placement? Im guessing before the circulator. Am I right assuming that?

hot_rod

I would suggest a micro bubble style air purger over a scoop type. All brands work in the 95% efficiency range.

And with all those old steel tanks I would highly recommend a dirt seperator with magnetic function.

Or a combo unit that would cover all 3 functions.