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[NaturallyAspirated]

Trust me on going with radiant heat, ITS almost like CRACK - with out all the horrible side affect. 
Once you have radiant you will not know how you lived with out it.  No more cold tile floor, for the wife to complain about when running to the bathroom in the middle of the night.

In regards to how to hook up system, may want to scope out the Central Boiler website - they have soem pretty good illistrations on how to hook up different application, even mulitboiler. 

Also, you can get away with not having a back up; heat source, pump, fill in the blank.  Just remember MURPHY's LAW - everythign seems to break just after close on the coldest day, darkest night ....
  I woudl never install a heating system with only one heat source, yes new equipment is less likely to break, but it does not mean it WON'T.

Have you started looking into what your BTU load will be for your set up???  Cause your OWB, might need to be a BEAST (If memory serves, garage = 120' x 60' = 7200sf) + SnowMelt + DHW + Hot Tub + Pool = ALOT of BTU's I feel

Indeed, but I need the geo for cooling in the summer.

Neal

[NaturallyAspirated]

This glycol thread got me thinking http://outdoorwoodfurnaceinfo.com/forum/index.php?topic=5181.0

What about designing this (my proposed) system with no antifreeze at all.  Collecting temp data from the OWF and outside slab circuits I could keep the temp above freezing.

I did intend to already have all circulators on a UPS unit, and it would be designed to hold until the backup generator came online, in the case of a power outage.

Going with a 100% water system would allow me to rid the design of multiple FPHE, as well as lower the maintenance, keeping the glycol mix at the proper ratio, as well as the glycol breaking down.

Seems to me it would be much simpler to write a few lines of emergency code to keep the temps up in the necessary circuits, rather than dealing with glycol injection and/or replacement on multiple circuits.

Neal

[LittleJohn]

YES, not having FPHE makes things some what less complex (by complex I mean CHEAPER  ).  FPHE are not a bad thing - when system is designed and sized correctly; like all things radiant

However if you are thinking about adding DHW or a back-up gas boiler you will most CERTAINLY need a FPHE or some other type of heat exchanger; cause most gas boilers lose warrenties over little things like, beign in an open system (FINE PRINT KINDA STUFF).

[NaturallyAspirated]

Reworked the drawing a bit, it is getting a bit more involved now, but I think I fixed up the issues with getting the full BTUs out of the stove and into a buffer/storage tank at manageable velocities.  I also broke out the loads into three primary circuits that utilize the stratification of the storage tank, drawing the radiant floor circuits from the bottom of the tank and the SIM and forced air exchangers from the top.  It also covers me a little on the spring and fall crossover days, I can run the heat pump in chilling mode and run the forced air for cooling during the high heat of the day and have the storage tank heated for night time radiant heating requirements.  I also have some three way valves in place to utilize the desuper portion of the heat pump for DHW heating and hot tub heating during the main chilling sequence during summertime.  I was hoping to be able to harvest some hour by hour forecasting to incorporate into the outdoor reset program and PID control via the control PLC.

Previous Version:
http://www.nealmastel.com/FS/geo-furnace.pdf

Present Version:
http://www.nealmastel.com/FS/geo-furnace-rev1-1.pdf

The new config should have layer options - such that you should be able to turn off or on layers to isolate certain circuits, making it much easier to navigate.  In Adobe Reader: View>Navigation Panels>Layers.  Let me know if it works, I did notice a few items that needed to be put on the proper layers.   

Neal

[Sprinter]

Nice bit of work there.
Consistent temp control and destratification problems I see.
Should always mix down to get to supply temp. When pulling by layer, the supply always has to be higher than the return, as shown the return will destrat the tank or make for very inconsistent temps.
On the load loop with fan coils, they should be series loops piped in parallel otherwise each downstream circuit will have lower supply temps regardless of how much the primary circ is moving. Header size will have some impact.
Are those two ZV's on each WB S&R circuit? Explain?
You have a lot going on there, I think you might be able to eliminate a few ZV's

[NaturallyAspirated]

Nice bit of work there.
Consistent temp control and destratification problems I see.
Should always mix down to get to supply temp. When pulling by layer, the supply always has to be higher than the return, as shown the return will destrat the tank or make for very inconsistent temps.
On the load loop with fan coils, they should be series loops piped in parallel otherwise each downstream circuit will have lower supply temps regardless of how much the primary circ is moving. Header size will have some impact.
Are those two ZV's on each WB S&R circuit? Explain?
You have a lot going on there, I think you might be able to eliminate a few ZV's

I should be able to pull supply above return for 3rd primary loop.  I think I will end up with a custom tank build.  I was obviously working with the graphic instead of building my own tank design.  I will work on that for the next step.  Good catch. 

The zone valves on the supply and return lines are to isolate the tank from the thermal siphon of the owf circuits when the tank is in chilling mode.  Perhaps not necessary if all the piping is routed properly from overhead.

Neal

[NaturallyAspirated]

Also I can place the fan coils in priority loading in controller design.  The main one is for the living space forced air system, the other two are for garage/shop cooling and are less important.   2" mains should cover it but I am still running some load analysis for the building.

Neal

[TheBoiler]

Looks mainly an open system, did you mean to do that?

External concrete slabs will such a lot of btu's.

[NaturallyAspirated]

Looks mainly an open system, did you mean to do that?

External concrete slabs will such a lot of btu's.

What do you mean?

Yes they do, that's why I have a larger sized furnace and a storage tank.  I hope to idle it at 40* or so.   

Neal

[TheBoiler]

The OWB is not pressurized and seems to feed straight into the rest of the system with no heat exchanger?

How big is the slab that you are looking to ice melt on, I would seriously have a glycol mix in that, if it was clod and dry you would not want to heat it.

[NaturallyAspirated]

The OWB is not pressurized and seems to feed straight into the rest of the system with no heat exchanger?

How big is the slab that you are looking to ice melt on, I would seriously have a glycol mix in that, if it was clod and dry you would not want to heat it.

The OWB is not pressurized, and it feeds into the tank via dual coil heat exchangers.   A & B are the primary coil exchanger connection points, and H & G are the connections for the secondary coil exchanger.  Any of the ports labels 1. are pressurized supply and returns of the tank.

The rest of the system is pressurized. 

24x42 for the large slab.  The slabs will by glycol circuits, as well as the boiler most likely.

Neal

[mlappin]

The OWB is not pressurized and seems to feed straight into the rest of the system with no heat exchanger?

How big is the slab that you are looking to ice melt on, I would seriously have a glycol mix in that, if it was clod and dry you would not want to heat it.

The OWB is not pressurized, and it feeds into the tank via dual coil heat exchangers.   A & B are the primary coil exchanger connection points, and H & G are the connections for the secondary coil exchanger.  Any of the ports labels 1. are pressurized supply and returns of the tank.

The rest of the system is pressurized. 

24x42 for the large slab.  The slabs will by glycol circuits, as well as the boiler most likely.

Neal

Good thinking on the slabs, we've had plenty of bitterly cold days this last winter but zero snow.

I only have the sidewalk melter, used a separate 5 gallon tank and 20 fphe for that, still a large draw on the rest of the system when it's first started. Especially if it's been below zero for a considerable amount of time. Have never timed it but eventually the return water from the slab is within 15 degrees of the supply.

[NaturallyAspirated]

The OWB is not pressurized and seems to feed straight into the rest of the system with no heat exchanger?

How big is the slab that you are looking to ice melt on, I would seriously have a glycol mix in that, if it was clod and dry you would not want to heat it.

The OWB is not pressurized, and it feeds into the tank via dual coil heat exchangers.   A & B are the primary coil exchanger connection points, and H & G are the connections for the secondary coil exchanger.  Any of the ports labels 1. are pressurized supply and returns of the tank.

The rest of the system is pressurized. 

24x42 for the large slab.  The slabs will by glycol circuits, as well as the boiler most likely.

Neal

Good thinking on the slabs, we've had plenty of bitterly cold days this last winter but zero snow.

I only have the sidewalk melter, used a separate 5 gallon tank and 20 fphe for that, still a large draw on the rest of the system when it's first started. Especially if it's been below zero for a considerable amount of time. Have never timed it but eventually the return water from the slab is within 15 degrees of the supply.

Do you idle it at all or just engage the circuit when necessary?

I'm also hoping to utilize the slabs as chill sinks in the summer time.  On nights when it gets into the 60s I can help the geo unit chill the tank.

Neal

[Jwood]

I like all the ideas you have Neil, but the only question I have is will you ever see a payoff? It just sounds so expensive, maybe that is not an issue I don't know all the pictures of this build should be fun to look at.

[NaturallyAspirated]

I like all the ideas you have Neil, but the only question I have is will you ever see a payoff? It just sounds so expensive, maybe that is not an issue I don't know all the pictures of this build should be fun to look at.

I dunno, at $3-$4k saved per winter I bet I will see payback before the furnace dies.  At least I hope so..... 

Neal