Wood/Solar/Gas with pressurized storage and Hydraulic Seperator

[fixmyboat]

Hello All,

Well I think I have the plumbing side all sorted out. If anybody sees any room for improvement just holler. Now if it only had a brain! I've been weighing my options. I marked proposed locations for temperature sensors with T's. So at least 7 inputs and 9 outputs. I'd like to reduce this to as few as possible because it will allow a smaller (read cheaper) smart controller. I'm looking at a few options including a NoFo and a Deltasol-E.

Thanks for lookin

http://www.nofossil.org/index.php?choice=nfcs

http://www.resol.de/Preislisten/51.Catalogue_09.prlus.pdf Page 22 in catalogue

EDIT: Fixed link for second controller

 

[kabbott]

Wow that's scary.... Almost an exact copy of my system minus the solar.
A few questions: is the storage open or pressurized?

The pumps on the right/load side of the separator should be on the top/outlet.
The back to back pumps for storage would be better with one on the top, one on the bottom, both pumping away from the separator.
Think about the layout of the storage tank plumbing, Mine thermosiphons sometimes. Couple ways to fix this. One way would be to use a electronic ball valve or
some sort of zone valve wired to open when either pump runs.

As far as sensors I would want at least 3 in the tank, maybe 5 if pressurized. Inlet & outlet of boiler, And I have 2 on the inlet/outlet of my tank coil.
The top connection for the tank should probably be on the far right. Mine is not and when a zone calls when I am charging the tank the zone does not get full
temp water. If you move it over to the right past all the heating zones they will get the water from the boiler before the tank. I have not decided whether to change
mine or not, I just kill the storage pump when a zone calls for now.
If I get a chance in the next few days I will post the layout of mine with sensors.

Kris

Edit: After reading the title again I see it is pressurized. I would take a hard look at the simplest pressurized sticky. If i could get a tank in my basement
I would have taken that route.

 

[Nofossil]

The 'simplest pressurized storage' essentially uses the storage as the separator. You could actually plumb the left and right loops directly to storage rather than to the tees above and below storage. In either case, it eliminates the need for the storage circulator(s).

You'll want a variable speed circ with some sort of differential control on the solar circ. Depending on your control solution, some controllers can drive fixed-speed circs like the Taco 007 at variable speeds.

For power consumption reasons, I prefer fewer circs and more zone valves, but I'll admit that's personal preference. You don't need very high flow rates through a typical zone.

 

[fixmyboat]

Just the two gentleman I was hoping to hear from.

Kabbot I freely admit to being inspired by your post to investigate hydraulic separation. It makes sense and provides a nice compact install with lots of flexibility.

I put all the pumps on the cold side due to my understanding that they would be happier pushing colder/denser water. Whats the advantage to having them on the outlet?

Yes I see that thermosiphon may be an issue with my top/bottom storage plumbing. Looks like a zone valve wired to the pumps will be the answer. What I like about this configuration is that it will allow storage to work equally well in heating or charging mode. You are right that it may cause excessive temperature drop to the zones especially the baseboards. Killing the pumps would work or possible variable speed?

Question; if you pipe the storage to the far right of the load outlet side how does it function in heating mode?

If I go the NoFo route I'd stick sensors all over the place. If I use the Deltasol-ES I need to limit it to 8 inputs and 7 outputs. Is there a real advantage to knowing the temperature of the middle of the tank? Also wouldn't the sensors at the beginning of the load output and source input arms of the seperator give you the water temp going to all zones and the return temp to all sources except storage without separate sensors? Id have to at least put one on the hot side of the storage to get an accurate reading while charging. Though if water going to the loads is hot enough to warrant storing and the house is warm then the water going out the top outlet to storage should be at least that hot if not hotter being closer to the source output arm? Makes sense to me anyway.....

Nofossill I used to live out your way and have learned much of what little I know from your excellent posts and website. The commercial pumps I'm considering will control 3 pumps variable speed. The solar store guys in Waterbury recommend it for my application. I'd like to run VS on the solar, on the wood boiler for protection, and on the radiant for outdoor reset. I know its a pump centric approach but as with everything in my system I've managed to scrounge them up for cheap on ebay/craigslist and at any given time only 2-3 will be running.

I'm pretty well wed to the separator....... I already had it welded up and honestly I'm quite happy with it.

Thanks for the input and I'll follow up on the Nofo forum with specific controller questions.

 

[kabbott]

When I first posted I did not notice the title said PRESSURIZED, so that will change my thoughts a bit.

First the theory on the pumps: The PONPC will be the expansion tank so all pumps should be pumping away from the separator. In practice many work fine
pumping towards the PONPC but if your starting from scratch.........I have seen my share of systems with pumps on the return pumping into the boiler/expansion
tank that have worked fine for years but why chance it.

For the storage: You have the storage in the center which may be a little better than mine. I planned to plumb mine that way but ended up using my taps
for aqua-stat wells. My storage is plumbed on the boiler side of the exchanger and the flow almost matches the boiler pump so when I am charging the tank
there is little/no flow from one side of HS to the other, zones get no hot water. Worst case for yours is mixed temp water, prolly not a big deal. If you plumb
it to the far right side it will get it,s water last,after all zones when charging. When heating from storage there will be no flow in top of HS, just flow in
from storage and right back out to zones in the top manifold. Not perfect for sure but I think acceptable depending on what/how many zones running.It
could be a problem if all zones are on as the one closest to the tank feed will get most of the hottest water.

There is another solution to this that may require a drawing. Put the storage charge pump on top right of the separator WITH a check valve. When charging
storage check valve opens and water flow in through bottom pump. Now picture a tee cut in above the top pump, on the tee put a zone valve. Now from zone valve
plumb to left top of HS. When heating from tank turn on bottom pump and open zone valve. Water can not flow in top pump because of check and must
flow through zone valve to BOILER side of HS. I did not want to confuse you before but I THINK this is the best solution. It still uses only one zone valve
but puts the water in the right place for both charging and heating.

For the sensors: Keep in mind my storage is open so I wanted to know the temp of my exchanger in/out as it is not necessarily the same as my tank.
The more sensors in the tank the easier it is to determine the amount of "charge" especially with the closed tank you can follow the hot water down the tank
as you charge and this will help determined if you need another load of wood for instance.

I would use:
IN/OUT wood boiler
IN/OUT storage
at least 3 in storage
and maybe feed/return on the load side of the HS.

You are correct that two sensors will cover the loads as they all see the same water.

Nofo can handle the solar and it's control. I have plans for solar so I will be taking notes.

Kris

 

[Nofossil]

Other than a fanatical obsession with sensors, my reason for sensors in the middle of the storage tank is to provide a better sense of how much heat is available. If you have good stratification in the tank, a tank at 10% and 90% could have virtually the same top and bottom temperatures. I like to have an idea of how much heat I have left so that I can figure out if I can have a beer or if I need to build a fire.

Here's my control panel - note the left gauge.

 

[kabbott]

What the heck!! I want one. I must have missed the source code for that! :coolgrin:

 

[fixmyboat]

Dude those vintage dials are awesome! Reminds me of the controls of old racing paddle wheelers. One more reason to get Nofo. Kabbot your storage plumbing suggestions make total sense I'll let them stew a bit and post plumbing revision. P.O.N.P.C. Point Of No Pressure Change.......that one took a minute.

 

[kabbott]

Here is a rough layout with the zone valve/storage circuit i was thinking of

 

[Vtgent49]

Hi,

I'm Waterbury also, and have boats too!

Does that HSeperator completely seperate the fluids, like a side arm? Seems that either the solar, or the entire heat/baseboard system needs glycol?

And, if yes, then don't you also need a second expansion tank? Also, there doesn't seem to be enough surface area to exchange all the heat required, but it may just be that I don't quite understand your set-up.

Al

 

[fixmyboat]

would you still need the check valve on the storage charging circ. to prevent thermosiphoning?

 

[kabbott]

would you still need the check valve on the storage charging circ. to prevent thermosiphoning?

Yes the top right pump should have a check to work properly. Actually all the pumps EXCEPT for the bottom storage pump could have built in checks.
For what its worth I used taco 00R 3 speed pumps on my storage, came with checks but they pull right out. They also dropped right into my 007 zone pumps.
I bought my 007 from pexsupply for like $62.00 without checks and used the ones from my 00R's.

 

[kabbott]

Hi,

I'm Waterbury also, and have boats too!

Does that HSeperator completely seperate the fluids, like a side arm? Seems that either the solar, or the entire heat/baseboard system needs glycol?

And, if yes, then don't you also need a second expansion tank? Also, there doesn't seem to be enough surface area to exchange all the heat required, but it may just be that I don't quite understand your set-up.

Al

No the HS does not isolate fluids. You bring up a good point. I was thinking off adding a coil in my tank for solar but that could get tricky with pressurised storage.
I would say glycol for the entire system is out since he will have a large storage tank, lots-a-glycol.

So fixmyboat are you planning a flat plate or what?

No practical way to do drain down with a closed pressure system is there?

 

[fixmyboat]

Solar radiation being what it is in VT in the winter I plan to drain in the fall. A couple of well placed manual shut of valves and spigots will let me close the loop off and then drain. I have the solar collectors but I wont get them installed till spring at the earliest. The other option would be drain back with a insulated tank in the attic.

VTgent49 here is a link about hydraulic separation. Essentially its Primary/secondary minus one pump.
http://www.pmengineer.com/Articles/Cover_Story/BNP_GUID_9-5-2006_A_10000000000000166945

 

[Nofossil]

Lot of Vermont people on this thread (sorry, Kris). Maybe we should plan a wood heat party. I know some guys with a Froling in Waitsfield.....

 

[fixmyboat]

You know the Sun Wood guys right? I've talked with some of them seem like a good bunch. I'll go to a wood heat party as long it involves drinking beer :coolsmile:

 

[Vtgent49]

I agree re. draining the system for the Winter. However some great, long sunny days occur in Mar/April/May that are great for solar, yet have a threat of Freezing. Those days also don't need wood heat due to the sun blasting in the windows. Also, in March, our thick blood thinks 60 degrees is T shirt weather by then. My solar is separate loop, glycol filled, and to a coil in my 80 gal DHW tank. So, my preference is to not touch the solar, just let it go dormant (with glycol) when the wood heated DHW is going strong, say Oct 20-March 20?

I don't as yet see that your HS setup is as efficient as I'd like, but it may be that I don't understand it yet. That Summer setup is not nearly direct enough for me, if the only purpose is to heat DHW (with a coil in that tank?)

Re Party/beer? I have room for 25 or so for dinner, and can easily cook for that many, with some pot luck contributions? However, viewing my 80's style system may not be that cool, for serious THC readers. But the offer is open. [email protected] if you want.

Al

 

[fixmyboat]

Many of my system choices were dictated by what I could scrounge up. Dual coil tanks are big bucks. I found a new single coil Buderus 40 gal for $400. Then I looked at the average solar radiation for a winters day (4-8000 btu's or something equally pathetic) and threw the gycol deal out the window. I may try a drain back system or possibly score another single coil tank to use as a HX. But the way mine is plumbed is the simplest. It looks funky but hot water actually flows directly from the collector to any load or all loads. The deltasol controller has a interesting feature that will cycle the solar circ. if the loop nears freezing so if I go that route I could make use of that for the shoulder season. The beauty of storage is that I can use my WB to provide DHW well past frost danger without overheating the house.

 

[kabbott]

I like the idea of having the solar directly into the storage tank( via the hydraulic separator) Seems like it would work well with no heat exchanger losses.
There has been a lot of discussion lately on using an open expansion tank mounted higher than the rest of the system. Seems like this may be a good
candidate for solar drain-back, Put the expansion tank higher than everything except the solar. Rig the solar to drain when the temps fall but the rest
of the system stays full. Could this be made to work.

With pressurized system I don't see how you can do drain-back without either, 1 a pump that is strong enough to over come the pressure, or 2 introduce
fresh water every time you drain/refill.

I have not taken Hearth.com solar 101 yet: Somebody educate me on solar setups.

 

[fixmyboat]

My understanding of drain back is an insulated non-corrosive tank above the rest of the system but bellow the solar with enough space in it to contain all the water in the collectors and its piping. You need a bronze or stainless pump powerful enough to push the water to the top of the collector. In the slickest installs this is a solar powered pump otherwise you need some sort of radiation sensor to turn it on or off. Then another pump circulates water out of the drain back tank to the rest of the distribution system. The problem I see with using this tank as an expansion tank is monitoring the water level. If it looses air it wont drain back fully then it freezes and you have a mess.

 

[Fred61]

I have a 105 gallon dual coil Steibel Eltron tank I'm going to sell. I used it for two years. If your interested PM me.