What is the heat loss through the windows of a passenger train left outside a station in winter, assuming that the temperature inside the train is 20°C, outside the train, -20°C, total heat transfer area 40 m². The thickness of glass wall may be taken as 0.5 cm. The thermal conductivity of glass is 0.88 W/(m.K).

What is the heat loss through the windows of a passenger train left outside a station in winter, assuming that the temperature inside the train is 20°C, outside the train, -20°C, total heat transfer area 40 m². The thickness of glass wall may be taken as 0.5 cm. The thermal conductivity of glass is 0.88 W/(m.K).

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.

Chapter1: Basic Modes Of Heat Transfer

Section: Chapter Questions

Problem 1.20P: A high-speed computer is located in a temperature-controlled room at 26C. When the machine is...

See similar textbooks

Similar questions

Using Table 1.4 as a guide, prepare a similar table showing the orders of magnitude of the thermal resistances of a unit area for convection between a surface and various fluids.
1.29 A spherical interplanetary probe with a 30-cm diameter contains electronic equipment that dissipates 100 W. If the probe surface has an emissivity of 0.8, what is its surface temperature in outer space? State your assumptions in the calculations.
Show that the rate of heat conduction per unit length through a long, hollow cylinder of inner radius ri and outer radius ro, made of a material whose thermal conductivity varies linearly with temperature, is given by qkL=TiTo(rori)/kmA where Ti = temperature at the inner surface To = temperature at the outer surface A=2(rori)/ln(ro/ri)km=ko[1+k(Ti+To)/2]L=lenthofcyclinder
A steam pipe 200 mm in diameter passes through a large basement room. The temperature of the pipe wall is 500C, while that of the ambient air in the room is 20C. Determine the heat transfer rate by convection and radiation per unit length of steam pipe if the emissivity of the pipe surface is 0.8 and the natural convection heat transfer coefficient has been determined to be 10 W/m2K.
1.10 A heat flux meter at the outer (cold) wall of a concrete building indicates that the heat loss through a wall of 10-cm thickness is . If a thermocouple at the inner surface of the wall indicates a temperature of 22°C while another at the outer surface shows 6°C, calculate the thermal conductivity of the concrete and compare your result with the value in Appendix 2, Table 11.
1.76 Explain a fundamental characteristic that differentiates conduction from convection and radiation.
One end of a 0.3-m-long steel rod is connected to a wall at 204C. The other end is connected to a wall that is maintained at 93C. Air is blown across the rod so that a heat transfer coefficient of 17W/m2 K is maintained over the entire surface. If the diameter of the rod is 5 cm and the temperature of the air is 38C, what is the net rate of heat loss to the air?
The heat transfer rate from hot air by convection at 100C flowing over one side of a flat plate with dimensions 0.1m0.5m is determined to be 125 W when the surface of the plate is kept at 30C. What is the average convection heat transfer coefficient between the plate and the air?
A high-speed computer is located in a temperature-controlled room at 26C. When the machine is operating, its internal heat generation rate is estimated to be 800 W. The external surface temperature of the computer is to be maintained below 85C. The heat transfer coefficient for the surface of the computer is estimated to be 10W/m2K. What surface area would be necessary to assure safe operation of this machine? Comment on ways to reduce this area.
The thermal conductivity of fibreglass insulation at 67F is 0.02 Btu/h ft F. What is its value in SI units?
Convection heat transfer from a plate (2 m x 2 m) is 450 W. If surface temperature of plate is 450 K and surrounding temperature is 300 K, what will be value of heat transfer coefficient?
A pipe passes through a room in which the surrounding air is at 22 ºC. The diameter of the pipe is 200 mm, the length of the pipe is 3metersand its surface temperature is 250ºC and the emissivity of the surface is 0.9 What is the surface emissive power (radiation heat loss)? If convection heat transfer coefficient from the surface to the air is 20 W/m2.K, what is the rate of heat loss from the surface of pipe by convection? Total heat loss from the surface of the pipe per unit length