The furnace is at 750 F and the convective heat transfer coefficient inside and outside of the furnace are 40 and 10 Btu/ft².F.hr respectively.

To evaluate the warm-up time of the furnace, assume it is initially at ambient temperature and suddenly exposed to 750 F gas.

a)Find the heat transfer.

b) Calculate the amount of heat lost to the ambient

c) determine the maximum and minimum temperatures in the stainless steel

d) determine the maximum and minimum temperatures in the calcium silicate

c)Approximately how long it will take to reach steady state?

Furnace internal dimensions: 2' x 4'

Furnace walls: Stainless Steel, 1" thick

Insulation: Calcium Silicate, 4" thick

Thermal Conductivity of stainless steel is 15W/m-K

Thermal Conductivity of calcium silicate is 0.04 W/m-K

Ambient Temperature is 70F.

Length = 2ft

Width = 4ft

Thickness = 1/12 ft