Need help with plumbing new storage

warno

Hello everyone. I'm new here and have to say very nice site.

Im hoping I can have someone help out with plumbing my new hot water storage for my boiler system. I'm using a outdoor wood boiler to heat my water and I'm adding roughly 750 gallons of storage via 3 vertical propane tanks. My storage will be pressurized and heated through a plate heat exchanger. I have a rough drawing that I think may work but I would like input and advice from anyone willing to help out. My drawing is just basic showing circs. And flow right now, the final assembly will have all my valves and drains needed.

Here's my thinking
First I have the OPEN system OWB pushing water to my plate HX. This loop has the boiler protection valve on it.

Then from plate HX to my storage supply manifold. This manifold will be 1.5" pipe reducing at second tank to 1" then reducing again at third tank to 1/2". Correct me if I'm wrong but I think this is called reverse return parallel piping. The return line goes to the third tank at 1.5" then reduces to 1" at the second tank then again to 1/2" at the first tank. So that covers storage.

From my storage supply manifold I'll use a delta T pump to push water 90 feet through underground lines to the house to a manifold in the crawlspace made of 2.5" pipe. This manifold will have 4 ports and then the supply and return to storage. I'll tie into 1 port for my furnace HX then use another port back into the manifold with the return from HX. The 2 remaining ports will remain unused until I figure out what I want to do with my DHW. Then water returns from the manifold back to the storage tanks return piping.

Expansion is going in attic space in garage with fittings in the tops of all three tanks pitched to the final tank then a line ran up to the airtrol fitting. I was told I may not need an airtrol the way is draw but I'm not sure.

please any help would be greatly appreciated. Here's my drawing

[URL=http://s32.photobucket.com/user/warno_p/media/Mobile Uploads/20160310_210100_zpsypfhnukd.jpg.html][IMG]http://i32.photobucket.com/albums/d31/warno_p/Mobile Uploads/20160310_210100_zpsypfhnukd.jpg[/IMG][/URL]

warno

I realized my link didn't work, and I wasn't sure how to edit my post so I attached a picture in this post.

Zman

If you have not read Idronics 10, I would recommend it. http://www.caleffi.com/sites/default/files/coll_attach_file/idronics_10_0.pdf

I few thoughts:
The flat plate exchanger should be piped with counterflow.
By pressurizing the storage tanks, you are going to need a humongous expansion tank. You might consider putting them on the unpressurized side. What is the elevation difference between the boiler and the garage?

The boiler circulator is going to be vulnerable to cavitation. Mount it as low as possible and select a heat exchanger and thermostatic valve with low resistance.

All circulators should pump away from the expansion tank. The one on the supply side of the heat exchanger should be on the return.

A 1" pipe is not 2x the size of a 1/2" pipe. Size the piping based on flow requirements. 4 fps should work for reverse return.

I don't see the need for the delta t circulator. The zone circs could easily pull the water from the storage tanks.

Be sure to size the underground lines generously.

warno

Thank you for the reply

I have read that pdf. It's very informative.

I didn't draw it showing this but the boiler circ will be in the boiler shed mounted about 12" off the ground. It will have about 40 gallons of water pushing down on it.

So my expansion tank mounted to a header on the tops of my storage tanks won't work?

What is a good step down piping size for 4 FPS flow?

The reasoning for pressurized storage is because my boiler vent is about 14" below the tops of the vertical tanks. So I figured to utilize my space best it would be to pressurize my tanks.

After I drew it I did realized that plate HXs are counter flow. So my HX to storage circ would be on the "return" manifold of the tanks. I have this same question on another site and was informed to plumb the HX so it convects heat to storage without running the circ and if the HX gets too warm turn on the circ via an aquastat.

Zman

Here is a calculator that will tell you FPS to GPM for a given pipe size. http://www.1728.org/flowrate.htm

If you start with the amount of energy you are trying to move you can then calculate the desired GPM.

After you have that, you can start playing with the best pipe sizes. Sometimes you will want to tweak the pipe sizes in order to utilize the most efficient circulator.

BTU/HR= GPM * delta t * 500

A 200 BTU/HR boiler with a design delta t of 20 would need flow rate of 20 GPM

1 1/2" copper pipe would be appropriate in this example. You might have to go with 2" PEX if the run is long because of the decreased inside diameter of the PEX piping.

Harvey Ramer

The boiler protection valve is not going to allow gravity flow to occur and is also an unnecessary expense with your setup. What you need to do is use a Taco setpoint circulator on the tank side of the heat exchanger. Attach the pump's sensor to the boiler return pipe, dial in your setpoint to 160° and flip the dip switch to reverse acting mode. The pump will start off in the slowest speed and the closer the boiler return comes to 160° the faster it will go till reaching full speed. I would still use the aquastat within the boiler to turn the boiler and tank pumps on once the boiler reaches a minimum temp.

warno

I already have the return protection valve from running this year, so I figured just put it back in the system. Are you saying the protection valve won't allow gravity feed from boiler to the HX? If so, I planned for that circ to run for as long as the boiler was firing then it will shut down.

Harvey Ramer

What model boiler protection valve is it?

warno

Caleffi thermomix valve 1"

Harvey Ramer

Yeah, that won't allow gravity circulation.

hot_rod

warno said:

Caleffi thermomix valve 1"

Doubt you would get much gravity heat through a plate type hx?

Stick with that boiler protection valve you have. It is either a 10 or 14 Cv, plenty of flow for your OWF.

Independant lab testing shows those OWF run about 45- 50% efficient burning 4" dry red oak blocks. So you only need to run about 10 gpm at a 20 ∆T. Good news if you only have 1" pex, because that is about all you will flow, realistically.

Harvey Ramer

Afraid I have to disagree on keeping the valve. The flow should be modulated on the tank side of the hx to allow tank stacking to occur. If the the valve is in place and the tank circ is full speed, the entire volume of water will be brought up to temp without any meaningful stacking. It will also take much longer to reach a usable water temp.

In my mind, it is a fatal design flaw.

Zman

The OP never stated what type or size OWB. I was just using an example. In order to dial in the actual sizing, you would need the the BTU rating and what type. Just guessing at this point.

warno

To answer question in last received to first order

My boiler is a homebuilt unit based off a manufactured design. I don't know the output for that reason. But I can heat 150 gallons from 170*F to 180*F in 7.5 minutes at about 4 gpm. For what that's worth. My flue temps range in the 400-450 degree F range. Hoping to bring that number down next year with more modification to the boiler HX tunnel.

The thermomix valve was going on the boiler side of the plate HX and that pump I planned to run constant. The storage side pump I was told to run on/off via temp reading of the HX output line to storage tanks. So the tank side of HX would thermosyphon to load the tanks unless the temps got too high leaving the HX then the pump would kick in drawing cool "lower" tank water through to cool off the HX.

Zman

You have an output of 100,000 BTU/HR. 10 GPM should work just fine.

hot_rod

warno said:

To answer question in last received to first order



My boiler is a homebuilt unit based off a manufactured design. I don't know the output for that reason. But I can heat 150 gallons from 170*F to 180*F in 7.5 minutes at about 4 gpm. For what that's worth. My flue temps range in the 400-450 degree F range. Hoping to bring that number down next year with more modification to the boiler HX tunnel.



The thermomix valve was going on the boiler side of the plate HX and that pump I planned to run constant. The storage side pump I was told to run on/off via temp reading of the HX output line to storage tanks. So the tank side of HX would thermosyphon to load the tanks unless the temps got too high leaving the HX then the pump would kick in drawing cool "lower" tank water through to cool off the HX.

Yes the valve is fine at the boiler. One more option, You could use a dual differential control for boiler and HX. On mine the controller fires up the boiler pump, a 281 Thermobloc when the top of the wood boiler hits 140. That pump would only run when there is enough heat in the boiler to add to the HX or tank, and you set a low limit.

I'm still no sure about thermosiphoning thru the plate type HX, worth a try.

Either the delta T pump or a differential controller on the HX to tank side.

With a delta T type solar controller you will get a lot more functions compared to a ∆T pump. Any of the digital, two output solar controller could nicely run both those pump with v/s plenty of speed control, hour meter, data logging and with a flowmeter you could have a BTU meter function enabled to see exactly what the boiler is capable of. The solar controller with a data logger or energy meter could also be put online.

Here is the control layout I use on mine with dual V/s ∆T functions and a list of the adjustable options

warno

How much do those type of pumps run? I was only thinking the delta T pump to help return temps back to the storage tanks from heat load. I was going to run grundfos 15-58s everywhere else.

hot_rod

The controller has the logic built into it. You can use any brand PSC motor, pump you want up to a 1 amp load. The typical Grundfos 15-58, Taco 00 series Wilo Star, B&G, Armstrong, any brand or color you like really.

It will not vary the speed of an ECM style circulator however.

There are 8 different system layouts programed into the controller some are ∆T function, some are set point, or a combination of.

The one I showed above is two ∆T functions, pump speeds up as temperature in the boiler increases on relay 1. The boiler is taking the place of the collector shown in the drawing.

Relay 2 runs your HX to tank pump with the same logic, the warmer the HX the faster it loads to the tank.

On and off temperatures are adjustable DTO (delta t on) and DTF (delta T off) are ∆T on and off. So you can adjust how much warmer the boiler is than the load before it turns on and off.

RIS (rise) is adjustable to adjust how and when the pump ramps up, factory set at 4 so every 4° increase in temperature the pump speeds up. So you can adjust and get the exact performance you desire.

It will also log HP (hours on pump) how many hours each pump runs to dial in performance or trouble shoot a mis-placed sensor, for example.

The display shows the various sensor temperatures, what the pump speeds are, hours on the pumps and flashes error codes if sensors fail. I doubt you get that much control access on the ∆T circs?

warno

That's alot of features. When I asked how much they run I meant money wise. LOL but that sounds like a very nice ability to monitor all those items.

This is the delta T pump I was looking at
http://www.taco-hvac.com/vr2218/index.html

So I'm getting alot of information, which is what I need, but it's all kind of running together now. So you guys are suggesting I run the "more advanced" pump on the boiler side or the storage side of the HX?

I planned on just running a basic run of the mill pump on the both sides of the HX. My boiler was going to be batch burning so I'm going to be running a flue sensor to shut the boiler down when it's out of wood. So basically I would get what I get from the burn. Again I didn't draw it in but I planned on a heat dump loop in the garage for when storage was up to temp but the boiler was still burning.

SWEI

warno said:

I planned on a heat dump loop in the garage for when storage was up to temp but the boiler was still burning.

Pipe that loop so it works on gravity circulation if at all possible.

warno

I planned on using a small air handler with a water to air HX. I know that in a power out situation it's best to run with a gravity setup but my boiler is forced air with a spring loaded damper that will snap shut if the power goes out. Plus I can probably count the power outs we've had on one hand since 2009.

hot_rod

Shop around for a dual output solar controller, it can be added anytime if you want to start with just basic 3 speed pumps for now.

As you are learning there are many ways to pipe and control these wood fired systems. Really it comes down to how much you want to spend and how much automatic control you want or need.

I have run my wood boiler for 9 years now, with a hand full of power outages I have never had an over-heat condition. With a draft assisted or fan induced type burn control they die down quickly. But every system is different, try and see how yours functions and add the required control.

Another component of wood burning is how interactive you want it. If you are around all day when it is burning, it could be a more manually operated and controlled system, toggle switches and 3 way ball valves for instance .

If you plan on filling the firebox and going away to work for the day, you may want more controls and safeties.

You will learn to build he fire size to the weather conditions and building loads, I rarely fire mine with a full firebox, I watch temperatures and incoming weather and load accordingly.

When I'm on the road the gals in the office flip a switch for the LP fired back up boiler or kick on heat pump. Although we all prefer the hydronic radiant floor heat to the air to air HP.

Burning wood for heat is not everybody cup of tea..

warno

I learned a TON of things this past winter being my first year burning. I have never watched the weather so much in my life. Lol

To let everyone know, my plan this coming winter was to go as cheap as possible but still doing it correctly. And to have a manual control system with sensors, switches and relays controlling everything. I have an electrical engineer doing my wiring diagrams to run everything. I have to leave for work in the morning and I'm home mid afternoon. So I'm hoping to get into batch burning for convenience, saving wood and burning cleaner. So hopefully I can burn a full batch and heat my storage to last all day/night.

warno

It might have got lost in the discussion but this is the pump I was looking at for my storage to house pump. I looked again at the manual pages and it has set point features as well as delta T features. So would this pump be ok for my storage to house loop?

http://www.supplyhouse.com/Taco-VT2218-HY1-FC1A01-Viridian-Delta-T-Variable-Speed-ECM-High-Efficiency-Circulator-Less-Flanges-Standard-120V

warno

I'm currently redoing my drawing and have a quick question. Referencing my original drawing, should my "HX to storage" loop be on its own manifold or will a single set of manifolds on my tanks be ok to charge storage and run to heat loads?

Zman

I like the way you designed that part of the system, it should work well.

warno

Ok that's what I wanted to hear. I'll continue my new drawing with that aspect. I should have my new drawing posted tonight or tomorrow, I would like any and all input on it. Thank you

warno

Heres my new drawing. I added in my heat dump loop and my garage heating loop.

All pumps I'm running are grundfos 15-58 circs except my storage to house pump. Which is a setpoint T pump.

Please any suggestions or input would be great.

Zman

Wood boilers love high temps. If it was just a wood boiler, you could size your emmiters for 160 degrees and let the wood boiler do it's thing.
The heat pump adds some complexity. They really work better at low water temps. So you would want emmiters sized for much lower temps.
Not sure I would put the heat pump on the depressurized side of the heat exchanger.
One way to do this would be to oversize the emmiters for low temp, then create a mixing loop after the storage tanks so that the water temps would be low when the boiler is running. This would maximize your storage as well.

warno

I had to go back and reread my self, but do you mean my heat DUMP? That's where if my wood boiler is over heating because my storage is up to temp and is still burning wood. A circ will kick on pushing boiler water through a water to HX with a blower fan to pull heat from the boiler to prevent a boiler over.

I don't have a heat pump system. It's all water to air heat exchangers.

Zman

"Never mind" ( Think Gilda Radner)
I thought you were using 2 heat sources.
Now it is just down to pipe sizing and putting in air eliminates, isolation valves and all the little stuff.

warno

So the drawing should work as drawn?


I am questioning if my expansion tank plumbing will be an issue. The more I thought about it, if my HX to storage pump is running it will be pushing directly towards my expansion tank tee fitting. Do I have anything to worry about as far as it forcing water up into the pipe?

Everything that could need replaced or maintained will be valved off. The tanks, the pumps, the HX, etc.

warno

Could anyone help me out with my expansion tank plumbing question?

Zman

What you have drawn is not ideal as far as expansion tank location, but it should work.
It isn't that the circulator will fill the tank with water. What you have with the circs so far apart will make air elimination more difficult. It has to do with Henry's law as it relates to gasses trapped in liquids.
A micro bubble separator in the garage and in the house should take care of this.
You will also need a good plan for your initial purge.

hot_rod

Why not connect it down on the return where you have that X

warno

Since this is all new, not installed yet, plumbing where would be the best location for the expansion tank to tie in?

Would it be better to put my "storage to house" circ in the garage and run my sensor into the house and attach it to the return in the house?

If I run mirco bubble separators where is the best place to install those? Just in front of the pumps?

warno

If it's on the return line will the returns from my loads be pushing at my expansion plumbing then? Is that a problem?

I'm really trying to ask the right questions. I'm wanting to do this install correctly.

hot_rod

Why not just one pump at the boiler, and a zone valve for the dump?

Air purger at the hottest point in the system, after the plate HX, expansion tank at that point with the buffer tank circuit pump after the purger.

The pumps for the garage and zone to the house are after the exp tank connection also.

All pumps are pumping away.

I'm not sure you need another pump at the house,as long as the pump from the tanks to the furnace is sized for that circuit, one pump is fine.

Add a DirtMag at the return to the plate HX if you are planning on ECM circ pumps.

warno

A zone valve for the heat dump would be a easy way too go. Thanks for that idea.

My highest point will be my garage heat loop. It is made up of 2 HX in the ceiling. So I should be ok with an air vent there and call it good?

For my expansion tank I planned to use a basic air tank in my rafters in my garage. I can get used propane tanks for next to nothing so I planned to modify those for expansion. Will that loaction still work for that style expansion?

I haven't sized my furnace HX yet so I don't know the head loss it will have, but my underground lines are 1" so if everything I've read is right after it runs to the house and back it will be about 12 ft of head. So, I'm not sure if a single pump and zone valves will run my house loop. especially after I add my DHW and possibly radiant floor in one room.

Which dirtmag would you recommend? There seems to be many to choose from. Also I planned to run a wye strainer to both sides of the plate HX, would that be ok?

hot_rod

It gets a little tricky when you use a plain steel tank for an expansion tank. You need to size and maintain an air bubble in it somehow. I know some folks have used them at the high point in the piping to help keep that bubble in. I think they pump in some air from time to time.

When the water in the system cools it can re-absorb some of that air, then when it heats again that air may be vented out.

You may need to run any air vent discharges to that tank to prevent venting away your expansion "bubble"

The Amtrol Design manual has some good reading on air management, compression tank systems.

B&G had an Airtrol fitting designed for systems with plain steel compression tanks. As it vented air from the boiler it directed it to the expansion bubble in the tank., I'm not sure how you would incorporate one in your piping layout.

Y-strainers work well, just be sure to clean them out occasionally

If the house will have multiple pumped circuits and mixed temperature zones, maybe a hydro sep would be a better choice where you show the house manifold.

warno

I forgot about my expansion tank when I said my garage loop was highest. Once my tank is up in my rafters of the garage that will be the highest point.

I'm wondering if I just build a separate "charging" manifold to charge my tanks from the HX. Then have my "supply" manifold for my loads, and tie my expansion into that line. That way my load pumps would be pumping away from the expansion lime and the charging pump wouldn't bother it. Would that work? If this is ok could I use a single "return" manifold? Or would that make things flow funny?