A steel pipe (outside diameter 100 mm) is covered with two layers of insulation. The inside layer, 40 mm thick, has a thermal conductivity of 0.07 W/(m K). The outside layer, 20 mm thick, has a thermal conductivity of 0.15 W/(m K). The pipe is used to convey steam at a pressure of 600 kPa. The outside temperature of insulation is 24°C. If the pipe is 10 m long, determine the following, assuming the resistance to conductive heat transfer in steel pipe and convective resistance on the steam side are negligible: a. The heat loss per hour. b. The interface temperature of insulation.

Approximately 106 discrete electrical components are placed on a single integrated circuit (chip) with electrical heat dissipation of q = 30,000 W/m². The chip, which is very thin, is exposed to a dielectric liquid at its outer surface, with ho = 450 W/m²/K and To= 20°C, and is joined to a circuit board at its inner surface. The thermal contact resistance between the chip and the board is R = 104 m² K/W, and the board thickness and thermal conductivity are L = 4 mm and 00,0 kb = 0.95 W/m/K, respectively. The other surface of the board is exposed to ambient air for which hi = 30 W/m²/K and T = 20°C. a) Provide a resistance diagram labeling appropriate variables associated with this problem. b) Determine a symbolic expression for the temperature of the chip T. c) Calculate the chip temperature for the given parameters. Coolant ho 00,01 Air Too,i hi 三 三 -Chip q Te -Thermal contact resistance, Re -Board, kp

Answer this ASAP,thx An empty sphere is made of aluminum (k = 202 W/m. °C) with an inner diameter of 4 cm and an outer diameter of 8 cm. The inside temperature is 100°C and If the ball above is coated with an insulating material having k = 50 mW/m. °C 1 cm thick. The outside of this insulation is in contact with an environment having h = 20 W/m.°C and Ts = 10°C, calculate the heat transfer under these conditions.

You are designing a 3m x 3m floor with radiant heating.  The floor has 12 parallel pex pipes (k = 40 W/mK) of L = 3m, OD = 25mm and ID = 20mm.  Hot water (TInfintiy 1 = 90oC, h = 200 W/m2K) runs through the pipes continuously.  The surface below the pipes is perfectly insulated.  Above the pipes, there is a 3mm layer of bonding material (? = 12 W/mK) and a 9mm layer of tile (k = 2 W/mK).  Above the tile, there is air (TInfinity 2 = 25oC, h = 20 W/m2K). Properties of Air: k = 0.025 W/mK, Pr = 0.72, v = 1.847 x 10−5, u = 16.84 x 10−6, p = 1.2 kg/m3, B = 1/Tf (ideal gas),  Hint: Assume that the “layer” of pipe starts at the center point (e.g. for conduction purposes, the pipe is OD divided by 2 thick).  For convection, consider the entire pipe surface. a) What is the total heat rate entering the room above the floor? b) What is the temperature of the top of the tile?

Calculate the heat loss through a 100-ft² wall with an inside temperature of 65°F and an outside temperature of 35°F. Assume the exterior wall is composed of 2- in. of material having a 'k' factor of 0.80, and 2-in. of insulation having a conductance of 0.16. RTotal = 8.75 & Q = 342-Btu/hr RTotal = 9.2 & Q = 399-Btu/hr RTotal = 8.75 & Q = 399-Btu/hr RTotal = 9.2 & Q = 342-Btu/hr Hide hint for Question 3 Utilize the (RTotal = 1/C + x1/k1) equation.

A thick-walled cylindrical tubing of hard rubber (k=0.151 W/m*K) having an inside radius of 5 mm and an outside radius of 20 mm is being used as a temporary cooling coil in a bath. Ice water is flowing rapidly inside, and the inside wall temperature is 275 K. The outside surface temperature is 300 K. A total of 20 W must be removed from the bath by the cooling coil. How many meter of tubing are needed?