Help designing radiant heat setup for 40 x 60 workshop

[hellspcangel911]

Hi All,
I’m in the process of getting the heating sorted for my workshop. I was hoping I could get some advice on my setup before I order the components. When I poured the slab I ran 7 loops of 1/2 “ pex, each about 300’ in anticipation of running a propane boiler.
It’s a steel building, 40 x 60, R-13 in the walls, R-19 for the roof, one large 12x14 door, two 8x9 doors. Its located in CT, looking to keep it around 55-60 degrees in the winter.
There is a 25 x30 loft on one side that will be additionally insulated and serve as an office. I’m hoping to run this as a separate heated zone off the same boiler.
So I’ looking at the Viessmann Vitodens 100-W B1HE-120 with a Caleffi 547 Series 1 ¼ hydraulic separator, Garage slab pump Grundfos Alpha1 15-55 and the Loft baseboard would use a Taco 007-F.
Any feedback or suggestions would be greatly appreciated.

Thank you

 

[fitter30]

67200 btu's, 7gpm@ 9'+2' = 11' head for loops
Micro bubbler for air removal, bladder tank for expansion, primary secondary loops with pex manifolds with flow meters. Glycol for boilers Not Automotive 30% minimum 50% max. This glycol needs 30% for the additive package and 50% is for pump efficiency. This. Glycol will protect either for freeze protection or slush manufacturer will have charts for both.
Boiler don't need or want a 199k boiler.
Standard fin tube/ aor handler is a problem they don't really start heating till water is 120° at 0° outside might need 160° or 180° that is to hot for radiate which runs 80°- 90. Condensing boilers have to run under 140° return water for the 95%+ efficiency. Colder the better. They do make fin tube for colder water. Just one brand
www.sterlingbaseboard.com/Synergy.html

 

[hellspcangel911]

Hi Fitter30, thanks for the response and running the calc. Thank you for pointing out the issue with mixing the two systems. Since the loft will run a low ambient mini split and be well insulated, I'll skip the fin tube all together. The 100-W B1HE-120 is a 120k btu, it should still have enough BTUs to add a few loops of radiant to the loft if it needs more heatbut the 10:1 should still be efficient if I dont, right?

 

[dscheidt]

Hi Fitter30, thanks for the response and running the calc. Thank you for pointing out the issue with mixing the two systems. Since the loft will run a low ambient mini split and be well insulated, I'll skip the fin tube all together. The 100-W B1HE-120 is a 120k btu, it should still have enough BTUs to add a few loops of radiant to the loft if it needs more heatbut the 10:1 should still be efficient if I dont, right?

It's not hard to build a system that can supply the correct supply temperature to the radiation in the zone. If you have high temperature radiation, you might have to run the boiler out of the ideal condensing range when it's cold, but it's probably not that much of your heating season. You can also install more radiation, either more or bigger fin tube, or radiators. Euro style panel radiators are available in sizes that have high outputs at low temperature. It's probably worth figuring out what's cheaper to run at your actual utility costs. Also, air to water heat pumps are a thing, though uncommon in the US. That will change, because replacing gas with electirc in existing buildings gets cheaper to run. (There's a bonus, too: most places you'd have a boiler for heating, the heat pump replacing it is more than big enough to cool it...)

 

[hellspcangel911]

Fair point, but the euro style radiators are more costly and though I like the look, they take up valuable wall space. Since I have access to the underside of the loft floor (garage ceiling), running a 3 loops of Pex should be pretty easy and cost effective.

 

[fitter30]

Hi hFitter30, thanks for the response and running the calc. Thank you for pointing out the issue with mixing the two systems. Since the loft will run a low ambient mini split and be well insulated, I'll skip the fin tube all together. The 100-W B1HE-120 is a 120k btu, it should still have enough BTUs to add a few loops of radiant to the loft if it needs more heatbut the 10:1 should still be efficient if I dont, right?

Can break it up with zone valves where Taco and others have controllers that take a t stat signal open a valve start a pump and boiler.

 

[TurnipTruck]

For your mezzanine, I used and recommend these ”staple-up” heat transfer plates. They are supposed to be good for 28 btu/ft which is quadruple what a bare pex tube in a joist bay can do, and you can use the same temperature water as the poured floor so you can maintain the high efficiency of your modcon boiler.

 

[hellspcangel911]

That Rauplate looks likea winner. Two seperate radint heating zones, one for the loft the other is the slab. I might just need to jump under each steel joist rather than cutting a 1.5" hole in them.
TurnipTruck- did you just do fiberglass batts under that or did you use any of the reflective insulation?

 

[TurnipTruck]

I had a bunch of paper back R11 fiberglass batting laying around from the remodel so that’s what I stuffed in the joist bays.

 

[hellspcangel911]

So Im looking at the Vissemann B1HE-85 (85k btu) model, non-combi, does that seem adequate? I feel like the next size up, 120K, is too too large and will short cycle in the shoulder months?