A double window called thermopane is one in which two layers of glass are used separated by a layer o dry stagnant air: In a given window, each of the glass layers is 6.35 mm thick separated by a 6.35 mm space of stagnant air. The thermal conductivity of the glass is 0.869 W/m K and that of air is 0.026 over the temperature range used. For temperature drop of 27.8 K over the system, calculate the heat loss for a window 0.914 m 1.83 m

A double window called thermopane is one in which two layers of glass are used separated by a layer o dry stagnant air: In a given window, each of the glass layers is 6.35 mm thick separated by a 6.35 mm space of stagnant air. The thermal conductivity of the glass is 0.869 W/m K and that of air is 0.026 over the temperature range used. For temperature drop of 27.8 K over the system, calculate the heat loss for a window 0.914 m 1.83 m

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter11: Heat Transfer By Radiation

Section: Chapter Questions

Problem 11.45P

See similar textbooks

Similar questions

An electrical transmission line of 1.2-cm diameter carries a current of 200 amps and has a resistance of 310-4 ohm per meter of length. If the air around this line is at v, determine the surface temperature on a windy day, assuming a wind blows across the line at 33 km/h.
A horizontal, 3-mm-thick flat-copper plate, 1-m long and 0.5-m wide, is exposed in air at 27C to radiation from the sun. If the total rate of solar radiation absorbed is 300 W and the combined radiation and convection heat transfer coefficients on the upper and lower surfaces are 20 and 15W/m2K, respectively, determine the equilibrium temperature of the plate.
The air-conditioning system in a Chevrolet van for use in desert climates is to be sized. The system is to maintain an interior temperature of 20C when the van travels at 100 km/h through dry air at 30C at night. If the top of the van is idealized as a flat plate 6 m long and 2 m wide and the sides as flat plates 3 m tall and 6 m long, estimate the rate at which heat must be removed from the interior to maintain the specified
The heat transfer coefficient for a gas flowing over a thin float plate 3-m long and 0.3-m wide varies with distance from the leading edge according to hc(x)=10x1/4Wm2K If the plate temperature is 170C and the gas temperature is 30C, calculate (a) the average heat transfer coefficient, (b) the rate of heat transfer between the plate and the gas, and (c) the local heat flux 2 m from the leading edge. Problem 1.18
A spherical communications satellite, 2 m in diameter, is placed in orbit around the earth. The satellite generates 1000 W of internal power from a small nuclear generator. If the surface of the satellite has an emittance of 0.3, and is shaded from solar radiation by the earth, estimate its surface temperature.
1.13 If the outer air temperature in Problem is –2°C, calculate the convection heat transfer coefficient between the outer surface of the window and the air, assuming radiation is negligible.
3.10 A spherical shell satellite (3-m-OD, 1.25-cm-thick stainless steel walls) re-enters the atmosphere from outer space. If its original temperature is 38°C, the effective average temperature of the atmosphere is 1093°C, and the effective heat transfer coefficient is , estimate the temperature of the shell after reentry, assuming the time of reentry is 10 min and the interior of the shell is evacuated.
5.7 The average Reynolds number for air passing in turbulent flow over a 2-m-long, flat plate is . Under these conditions, the average Nusselt number was found to be equal to 4150. Determine the average heat transfer coefficient for an oil having thermal properties similar to those in Appendix 2, Table 18, at at the same Reynolds number and flowing over the same plate.
(a) If the cost of producing the hot water is $0.10 per kWh, what is the representative daily costof heat loss from an uninsulated pipe to the air per meter of pipe length? The convectionresistance associated with water flow in the pipe may be neglected.(b) Determine the savings associated with application of a 10-mm-thick coating of urethaneinsulation (k = 0.026 W/m-K) to the outer surface of the pipe.
In presence of an external flow when will the convective heat transfer be dominated by free convection and not by the forced convection due to the external flow? Gr ≫ Re². Gr ≪ Re. Gr ≫ Re. Gr ≪ Re For ideal gases, the specific heat capacity at constant pressure, thermal conductivity, dynamic viscosity, and Prandtl number are independent of pressure. How will the ratio of thicknesses of velocity boundary layer and thermal boundary layer change if pressure is increased from 1 atm to 5 atm for the flow of an ideal gas over a flat plate? It will decrease by a factor of 5. It will remain the same. It will increase by a factor of 5. We need to know the actual fluid properties to tell.
The emissivity of galvanized steel sheet, a common roofing material, is ε = 0.13 at temperatures around 300 K, while its absorptivity for solar irradiation is αS = 0.65. Would the neighborhood cat be comfortable walking on a roof constructed of the material on a day when GS = 750 W/m2, T∞ = 16°C, and h = 7 W/m2 · K? Assume the bottom surface of the steel is insulated.