System design advice

RomanP

Hello, gents.

I'm trying to configure the best possible system design. Client wants to have: hot water, radiant floors(tiled areas) and HVAC units with hydronic coils. I will definitely use high efficiency, condensing equipment for hot water and radiant floors. My question is: should I dedicate a non-condensing boiler to constantly feed hydronic coils with 180-190 degree water. Or, will those hydronic coils perform just fine with a condensing system with an outdoor reset? ( supply temperature will adjust accordingly to outdoor temperature)

Thanks in advance!

SWEI

Outdoor reset works fabulously on hydro-air, but the curve will be quite different than that for RFH. I would set the boiler curve for the coils and then mix down for the floors using a Taco iSeries-R valve.

STEVEusaPA

Well first you need a room by room heat loss. That will tell you size of boiler, what you need for water temperatures, radiant loops, etc., and how to set your ODR curve.
Why not do the whole house with radiant? Either floors and/or ceilings.
You're running ducts too? Run air handlers/heat pumps (depending on climate) for back-up/shoulder seasons. It's not much to upgrade for AC to heat pump.
Then you can have your mod/con boiler with an indirect and a great comfortable system.

njtommy

You should be able to design your coils for 140 supply water temp. A few companies make ahus or furnaces like Rheem hydroair furnace and or Viessmenn air flow plus hydronic air handler.