Question

calculate the energy transfer rate in w/m² across 6 in wall of firebrick with a temperature difference across the wall of 55°C. the thermal conductivity of the firebrick is 0.65 BTU/hr ft °F.

Answer 1

$L=6 inches(2.54cm/(1 inch))=15.24cm$

$∆T=50℃$

$k= 0.65 Btu/hr-ft℉((1W/cm℃)/(57.79Btu/hr-ft℉))= 65/5779 W/cm℃$

$q_k/A=k/L ∆T$

$q_k/A= ( 65/5779 W/cm℃)/15.24cm × 50℃$

$q_k/A=0.0369 W/〖cm〗^2 = 369 W/m^2$