Question

A circular ceramic plate that can be modeled as a blackbody is being heated by an electrical heater. The plate is 30 cm in diameter and is situated in a surrounding ambient temperature of 15°C where the natural convection heat transfer coefficient is 12 W/m2·K. If the efficiency of the electrical heater to transfer heat to the plate is 80%, determine the electric power that the heater needs to keep the surface temperature of the plate at 220°C.

Answer 1

Q = 125.538 W

Step-by-step explanation:

Given data:

D = 30 cm

Temperature
`T_\infity = 15` degree celcius

`T_S =  220 + 273 = 473 K`

Heat coefficient = 12 W/m^2 K

Efficiency 80% = 0.8

`Q = hA(T_S - T_(\infty)) \eta`

`= 12((\pi)/(4) 0.3^2) (473 - 288) 0.8`

Q = 125.538 W