A very large industrial annealing furnace has a double wall constructed of 30cm of solid brickwork in
Question:
A very large industrial annealing furnace has a double wall constructed of 30cm of solid brickwork in contact with an outer cladding of 0.5cm of steel. Assume that the furnace has a total wall and roof surface area of 36m2 and ignore any heat loss into the floor. The inside of the furnace is maintained at a constant year round temperature of 800o C, and you can assume the air outside the furnace is at a constant 20o C. The convection coefficient for all solid-air surfaces can be assumed to be 20 Wm-2 K-1 , the thermal conductivity of brick is 0.6 Wm-1 K-1 , and the thermal conductivity of the steel is 40 Wm-1 K-1 . Calculate the energy loss per year through the walls and roof, and hence calculate the annual furnace energy costs if electricity costs 20p per kW.hour ("kilowatt hour").
Fundamentals Of Momentum Heat And Mass Transfer
ISBN: 9781118947463
6th Edition
Authors: James Welty, Gregory L. Rorrer, David G. Foster