Radiant floor heating systems provide heat to the floor via

Radiant floor heating systems provide heat to the floor via embedded hot water tubes or electrical wires and distribute the heat to the room via natural convection and radiation. We\'ll just consider the natural convection part here. The floor of a room 6 m times 8 m times 3 m high is heated to 25 C. The ceiling is not perfectly insulated so that heat is lost through the roof and the ceiling temperature is 20 C. What is the rate of heat transfer from the floor to the ceiling?

Solution

floor area 6*8 m^2

ht of room 3 m

floor temp 25C= 298K

temp of ceiling 20 C =293 K

Temp diff 5 K

heat lost hADT = h* 48* 5 = 240h

where h = film coeff for air.

From handbooks, h = 20 W/m² K

Heat transferred = 48*4*20 =4800 Watts ( 4.8 KW)