Two nested spherical tanks with the internal and outer diameters of the 100 cm by 104 cm and 114 cm by 118 cm is used to store hot water at 100°C. Both tanks are made of boron fiber epoxy with different composite compositions. The thermal conductivity of the inner tank is 1.5 W/m K while the outer tank has a thermal conductivity of 0.5 W/m K. The gap between the tanks is filled with air (use properties of air at 50°C). The tank is located in an open environment at 0'C. The outer surface of the tank is white painted and heat transfer between the outer surface of the tank and the surrounding is by natural covection and radiation. The convection heat transfer coefficient at the inner and the outer surface of the pipe is h= 20 W/m' K and h,= 10 W/m K. Determine ; a. the rate of heat loss from the tank b. the inside, outside and intermediate surface temperatures. Hint: Take the outer surface temperature as 3°C for radiation calculations.

A supply of 50 kg of chicken at 6degC contained in a box is to be frozen to -18degC in a freezer. Determine the amount of heat that needs to be removed. The latent heat of chicken is 247 kJ/kg and its specific heat is 3.32 kJ/kg-degC above freezing and 1.77 kJ/kg-degC below freezing. The freezing temperature of the chicken is -2.8degC

Consider a furnace (as a plane wall) which has a thickness of 15 cm and a surface area of 1 m?. The inside surface of the furnace wall (the hot left side of the wall) is at temperature T1. The furnace wall is made of brick with thermal conductivity of 1.198 W/m.K. The outside surface of the furnace wall (the right side of the wall) has a surface emissivity of 0.8 and is maintained at T2=101 °C and subject to air at 25 °C with convection heat transfer coefficient of 20 W/m?.K. The surroundings temperature at the outside of the furnace wall is at 25 °C. Required: Draw a clear and consistent schematic of the problem and label the operating conditions on the schematic. Perform systematic analysis, state your assumptions and justify the equation used and determine the following (circle your final answers): (i) The rate of heat transfer by convection (in W); (ii) The rate of heat radiation (in W); (iii) The surface temperature of the furnace wall T1 (in °C); (iv) The rate of conduction heat…

Consider a double-paned window consisting of two panes of glass, each with a thickness of 0.500 cm and an area of 0.795 m2 , separated by a layer of air with a thickness of 1.50 cm. The temperature on one side of the window is 0.00 ∘C∘C; the temperature on the other side is 21.0 ∘C∘C. In addition, note that the thermal conductivity of glass is roughly 36 times greater than that of air. Approximate the heat transfer through this window by ignoring the glass. That is, calculate the heat flow per second through 1.50 cmcm of air with a temperature difference of 21.0 ∘C∘C. (The exact result for the complete window is 25.6 J/sJ/s .)