posted by Maryo on .
The temperature in an electric oven is 160°C. The temperature at the outer surface in the kitchen is 50°C. The oven ( surface area = 1.6 m2) is insulated with material that has a thickness of 0.02 m and a thermal conductivity of 0.045 J/s.m.C°. (a) How much energy is used to operate the oven for six hours?(b) At the price of $0.1/kw-hr for electrical energy, what is the cost of operating the oven?
Anyone Can answer this Please
Calculate the heat loss rate through the walls, using
P = (surface area)*k*(110C)/0.02 m
where k is the thermal conducticity
Convert watts (J/s) to kilowatts. Multiply the number of kW by 6h to get the number of kW-hr.
That is the energy required for steady state ooperation for 6 hours. There will be an additional amount required to heat up the oven - probably a few percent more, depending upon the specific heat.