Radiant Slab
Thermally activated slab analysis: steady-state heat exchange between water in an embedded PEX loop, the room above and the space below.
Section
Return
– °F
– °F
Head loss
– ft H₂O
– ft H₂O
Floor – °F · to room – Btu/hr·ft²
water
Ceiling – °F · to space below – Btu/hr·ft²
The space below the slab is taken at the room temperature. Fluxes are per ft² of floor; positive = heating.
Results
Loop heat balance
–kBtu/hr
positive → heating
Return water
–°F
To room (up)
–Btu/hr·ft²
To space below
–Btu/hr·ft²
Floor surface
–°F
avg of loop start & end
Loop head loss
–ft H₂O
Along the loop
WaterFloor surfaceRoom
Resistance network (hr·ft²·°F/Btu, per ft² floor)
Model constants & numerics
Rebuild of JB&B's EES calculator JBBThermActSlabCalc v13. The engine is checked against 18 runs of the original (107 displayed values, all within display rounding; worst deviation 0.04%).