W The wall of a spherical steel tank k, = 17. m. K thick contains hot oil at 100°C. On the outside of the tank 10mm of spray urethane insulation k, = 0.026- of 1m in diameter and 100 mm is added to stop the oil from cooling. If the m. K outside temperature is 25°C, h=16- needs to be added to keep the tank at 100°C for pumping reasons? What are the overall heat transfer coefficients (Uo and U₁)? W 2 m².K and h = 5. 2 m².K how much heat

A glass window of width W = 1 m and height H = 2 m is 5 mm thick and has a thermal conductivity of k 1.4 W/m K. If the inner and outer surface temperatures of the glass are 15°C and -20°C, respectively, on a cold winter day, what is the rate of heat loss through the glass? To reduce heat loss through windows, it is cus- tomary to use a double pane construction in which adjoining panes are separated by an air space. If the spacing is 10 mm and the glass surfaces in contact with the air have temperatures of 10°C and -15°C, what is the rate of heat loss from a 1 m x 2 m window? The thermal conductivity of air is k, = 0.024 W/m.K.

A metallic sphere of radius R is heated in an oven to a temperature of 600 ° F throughout, and then removed from the oven and allowed to cool in ambient air to T∞ = 75 ° F, by convection and radiation (see attached figure). The thermal conductivity of the ball material is known to vary linearly with temperature. Assuming that the ball is uniformly cooled starting from the entire outer surface, obtain the differential equation that describes the change in temperature in the sphere during cooling. Note: In the image, the translation would be: metallic sphere

Hollow Sphere Saturated steam at 267°F is flowing inside a hollow sphere with an ID of 0.824 in. and an OD of 1.05 in. The pipe is insulated with 1.5 in. of insulation on the outside. The convective heat transfer coefficient inside and outside the pipe is hi = 1000 Btu/hr/ft2/°F and ho = 2 Btu/hr/ft2/°F, respectively. The mean thermal conductivity of the metal is 45 W/m/K or 26 Btu/hr/ft/°F, while that of the insulation material is 0.064 W/m/K or 0.037 Btu/hr/ft/°F. a. Calculate the heat loss for 1 ft of pipe using resistances if the surrounding air is at 80°F. b. Calculate the temperature profile developed for this system. c. Calculate the inside and outside overall heat transfer coefficients.