Consider a 0.6 m high and 1.2 m wide double-pane window consisting of two 4 mm thick layers of glass (k = 0.78 W/m·K) separated by a 10 mm wide stagnant air space (k = 0.026 W/m-K). Determine the steady rate of heat transfer through this double-pane window and the temperature of its inner surface for a day during which the room is maintained at 20°C while the temperature of the outdoors is -5 °C. Take the convection heat transfer coefficients on the inner and outer surfaces of the window to be

Consider a 0.6 m high and 1.2 m wide double-pane window consisting of two 4 mm thick layers of glass (k = 0.78 W/m·K) separated by a 10 mm wide stagnant air space (k = 0.026 W/m-K). Determine the steady rate of heat transfer through this double-pane window and the temperature of its inner surface for a day during which the room is maintained at 20°C while the temperature of the outdoors is -5 °C. Take the convection heat transfer coefficients on the inner and outer surfaces of the window to be

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

See similar textbooks

Similar questions

A common annoyance in cars during winter is the formation of fog on the glass surfaces that blocks the view. A practical way of solving this problem is to blow hot air or to attach electric resistance heaters to the inner surfaces. Consider the rear window of a car that consists of a 0.4-cm-thick glass (k = 0.84 W/m-K and a = 0.39 x 10-6 m2/s). Strip heater wires of negligible thickness are attached to the inner surface of the glass, 4 cm apart. Each wire generates heat at a rate of 25 W/m length. Initially, the entire car, including its windows, is at the outdoor temperature of To= -3°C. The heat transfer coefficients at the inner and outer surfaces of the glass can be taken to be h;= 6 and ho= 20 W/m².K, respectively. Use the explicit finite difference method with a mesh size of Ax = 0.2 cm along the thickness and Ay=1 cm in the direction normal to the heater wires. Inner surface Thermal -symmetry line 5 6 Heater 25 W/m 7 8 9 Outer surface Glass 0.2 cm 1 cm Thermal symmetry line 1)…
Hot-surface temperature of a 12-mm thick fire brick wall is maintained at 913 K. If the average thermal conductivity of the wall material is 0.123 W/m.K. Determine the maximum heat loss through the wall to ensure its cold-surface temperature does not exceed 364 K. For an ambient air temperature of 292 K, what is the surface coefficient of the wall material?
1. (a) Consider a room with a 1.8-m-high and 2.0-m-wide double-pane window consisting of two 4-mm-thick layers of glass separated by a 10-mm-wide stagnant air space. The convection heat transfer coefficients on the inner and outer surfaces of the window are 12 W/m2 K and 25 W/m2 K, respectively, while the average thermal conductivity of glass is 0.78 W/m K; and the air, 0.026 W/m K. If the room is maintained at 22 oC, the outside temperature is -4 oC and heat transfer due to radiation can be neglected, determine: (i) Draw the sketch and thermal resistance network; (ii) the total thermal resistance; (iii) the steady rate of heat transfer through this double-pane window; (iv) the temperature of the inner surface of the window.…
1. The upper surface of a 50-cm-thick solid brass plate (k=109 W/m·K) is being cooled by water with temperature of 10°C. The upper and lower surfaces of the solid plate maintained at constant temperatures of 60°C and 190°C, respectively. Determine the water convection heat transfer coefficient and the water temperature gradient at the upper plate surface. Water 1111 Ts,2
A 21.5-cm-wide and 31 cm high vertical hot surface in 20°C air is to be cooled by a heat sink with equally spaced fins of rectangular profile. The fins are 0.1 cm thick, 4 cm wide, and 31-cm- long in the vertical direction. Given: Consider the characteristic length to be the height of the surface. The properties of air at T₁ = 52.5°C: k = 0.02753 W/m °C, v= 1.823 × 10–5 m²/s, Pr = 0.7222 a. Determine the optimum fin spacing of the heat sink if the base temperature is 85°C. b. Determine the rate of heat transfer by natural convection from the heat sink if the base temperature is 85°C.
Consider a person standing in a room at 18°C. Determine the total rate of heat transfer from this person if the exposed surface area and the skin temperature of the person are 1.7 m2 and 32°C. respectively, and the convection heat transfer coefficient is 5 W/m2-K. Take the emissivity of the skin and the clothes to be 0.9, and assume the temperature of the inner surfaces of the room to be the same as the air temperature.
Radioactive material is stored in a spherical vessel with a diameter of 3.7 m, and the center of the vessel is 11 m below the ground. The vessel is surrounded by a 10.2 cm thick layer of rigid foam insulation (k = 0.026 W/m-K). The radioactive material releases heat at a rate of 1000 W/m³. The surface of the soil it's buried in (k = 2 W/m- K) is exposed to wind with a temperature of 20°C and a convection coefficient of 17 W/m²-K. What is the temperature of the surface of the tank?
The wall of a house is 4-meter-high and 15 -meter- wide. The wall is constructed with a 9-cm thick outer layer of brick and a 5-cm inner layer of insulating material. On a cold day, the outer surface temperature of the wall is -5°C while the inner surface temperature is 24°C. The thermal conductivity of the brick is 0.80 W/m-K, while the thermal conductivity of the insulation is 0.03 W/m-K . both inner and outer and outer has transfeer coefficeint of 20 W/m2- K a. What is the total thermal resistance of the wal? b. What is the rate of heat loss through the wal
When is the heat transfer through a fluid conduction and when is it convection? For which case is the rate of heat transfer higher? How does the convection heat transfer differ from the thermal conductivity of the fluid?
Calculate the temperature in an unheated space (Tunc) adjacent to a conditioned room with three (3) common surface areas of 175-ft2, 190-ft2, and 210-ft² with an overall heat transfer coefficient of 0.21, 0.27, and 0.32 Btu/h-Ft2 °F, respectively. The surface areas of the unheated space exposed to the outdoors are 175-ft² and 210-ft² with corresponding overall heat transfer coefficients of 0.21 and 0.40 Btu/h- Ft².°F. The sixth (6th) surface is on the ground and can be neglected for this example as can be the effect of any outdoor air entering the space. Inside & outside design reference temperatures are 70°F & -10°F, respectively. Tunc = 37°F Tunc = 36°F Tunc = 30°F Tunc = 35°F