In the design of a cold-storage warehouse, the specifications call for a maximum heat transfer through the warehouse walls of 30,000 joules per hour per square meter of wall when there is a 30°C temperature difference between the inside surface and the outside surface of the insulation. The two insulation materials being considered are as follows: Conductivity (J-m/m²-°C-hr) Cost per Cubic Meter $12.50 Insulation Material Rock wool 140 Foamed insulation 14.00 110 The basic equation for heat conduction through a wall is: K(AT) where Q=heat transfer, in J/hr/m2 of wall K=conductivity in J-m/m²-°C-hr AT =difference in temperature between the two surfaces, in °C L=thickness of insulating material, in meters %3D %3D Which insulation material should be selected?

Insulating material is used to reduce heat loss from the heating furnace walls to the room. The surface temperature of the insulating material is 100 ° C and the other surfaces 20 ° C. Allowable heat loss up to 140 W / m2 from the wall. If the thermal conductivity of the insulation material is 0.05 W / (m ° C), calculate the required thickness of insulation. insulation thickness = Answer cm

Q5B) A steel pipe of 170 mm inner diameter and 190 mm outer diameter with thermal conductivity 55 W/m. K is covered with two layers of insulation. The thickness of first layer is 25 mm (k = 0.1 W/m. K) and second layer thickness is 40 mm (k = 0.18 W/m.K). The temperature of steam and inner surface of steam pipe is 320 °C and outer surface of insulation is 80 °C. Ambient air temperature is 25 °C. The surface coefficient for inside and outside surfaces are 230 W/m². K and 6 W/m². K respectively. Determine the heat loss per meter length of steam pipe and layer of contact temperatures and also calculate overall heat transfer coefficient.

Find the thermal resistance r (in hr - °F/BTU) and the equivalent R-value (in hr ft?. °F/BTU) of a typical frame 20' x 7.5" wall consisting of a 0.5" plaster board on the inside of the room, nominai 2 x 4 studs, and a 0.5" sheathing on the outside. The spaces between the studs are filled with an R-15 insulating foam. What is the heat loss (in BTU) through this wall in four hours if the inside temperature is 72°F and the outside temperature is 32°F? (Assume that the 15% of the wall's area are studs and the remaining 85% is filled with the insulating foam. Assume that the air is moving outside the wall.) r= 0.0805 x hr: OF/BTU R=0.09 x hr ft2. F/BTU AQ = BTU

I am struggling with this question. Part a and b

In a lab testing material samples to determine the thermal conductivity of the material. Now, the test specimens are 18.5 cm long by 14.4 cm wide and 0.26 cm thick. The sample is placed in a test device so that one of the large sides is maintained at 13, while the other large side is kept at -7.  The heat transfer through the sample is measured to be 287 Watts.  Determine the thermal conductivity. Give your answer to 2 decimal places.

1. The thermal resistance of A, B, C, and D are 1, 2, 2, 4 W/ °C, respectively. The total thermal resistance to the wall conductance will be TAs = 200°C a. 9.0 W/ °C b. 5.5 W/ °C C. 6.0 W/ °C d. 16 W/ °C a. 0.672 b. 0.232 C. 0.0672 d. 0.023289 a. 250 W/mK b. 1.25 W/mK 6 cm C. 0.25 W/mK d. 0.125 W/mK A B с 2 cm 2.5 cm 3 cm g. 47.14% h. 14.14% 3 cm 2. The heat transfer due to radiation from a surface of 2 cm² area at 800 °C to a very cold enclosure is 5.0 W. Determine the emissivity of the surface at this temperature D 4 cm Problem 1.34 6 cm 3. An electric wire carrying current is covered with an insulating material. The critical diameter of the insulation is 10 mm. The outside air has heat transfer coefficient of 25 W/m² K TDs = 50°C 4. A hot potato is put in water bowl. Another hot potato of same temperature and size is kept in open air at same temperature that of water. Which potato will cool quicker and why? a. Potato in water bowl, as there will high convection comparatively b.…