A room is well insulated everywhere except for a glass large window, which is rectangular with length 2.50 m and height 1.60 m and has width 1.50 cm. Inside the room, the temperature is 20.0 degrees Celsius and outside is 38.0 degrees Celsius. To keep the inside of the room at a constant temperature, heat must be removed by an air conditioner at the

A room is well insulated everywhere except for a glass large window, which is rectangular with length 2.50 m and height 1.60 m and has width 1.50 cm. Inside the room, the temperature is 20.0 degrees Celsius and outside is 38.0 degrees Celsius. To keep the inside of the room at a constant temperature, heat must be removed by an air conditioner at the

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 11.54P

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1.26 Repeat Problem 1.25 but assume that the surface of the storage vessel has an absorbance (equal to the emittance) of 0.1. Then determine the rate of evaporation of the liquid oxygen in kilograms per second and pounds per hour, assuming that convection can be neglected. The heat of vaporization of oxygen at –183°C is .
H4. Solar flux = 900 [w/m^2] h_air from glass cover = 25 [w/m^2-k] Emissivity_glass = 0.88 (nearly opaque to low frequency radiation Transmissivity of glass = 0.95 Alpha to incoming radiaiton = 0.9 T_ambient = 17 C Gap between plates = 25mm Bottom plate is insulated. Hr = radiation heat Hc = convective heat might need to use view factor FIND TEMPERATURE OF TOP SURFACE (the top is the glass) If anything is needed let me know i will try my best to update the question
34.) A duct, consisted of four rectangular flat plates, are radiating with each otherand nothing else. Use the given data to find the radiosity and the rate of heattransfer for each surface. Data: Length = 1 m, depth, 2 m, height 0.5 m, T1 = 100C, T2 = 200 C, T3 = 300 C, T4 = 400 C, ε1 = 0.5, ε2 = 0.65, ε3 = 0.75, ε4 = 0.8. Thejoins are well insulated so that there is no heat transfer between the plates bythermal conduction.
Extrasolar Planets. In the not-too-distant future, it should be possible to detect the presence ofplanets moving around other stars by measuring the Doppler shift in the infrared light they emit. If a planetis going around its star at 50 km/h while emitting infrared light of frequency 3.330 x 1014 Hz, whatfrequency light will be received from this planet when it is moving directly away from us? (Note: Infraredlight is light having wavelengths longer than those of visible light.)
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A 3-in-diameter cylindrical wire is coated in 3 inches of polyethylene insulation. The wire can be modeled as a grey body with an emissivity of .85. Due to the electrical resistance, the wire is at a temperature of 300 degrees Celsius. The insulation is also a great body with an emissivity of .95, at a temperature of 40 degrees Celsius. (Assume F12=1). What is the heat flux (W/m^2) of the energy going from the wire to the insulation?
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A concrete ball of radius 2.32 m and emissivity 0.620 is heated to 123°C. (a) Convert the given temperature to Kelvin. (Enter your answer to at least three significant figures.) ?K (b) What is the surface area (in m2) of the ball? ?m2 (c) If the ambient temperature is 26.0°C, what net power (in W) does the ball radiate? ?W
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During periods of high activity, the Sun has more sunspots thanusual. Sunspots are cooler than the rest of the luminous layer of theSun’s atmosphere (the photosphere). Paradoxically, the total poweroutput of the active Sun is not lower than average but is the same orslightly higher than average. Work out the details of the followingcrude model of this phenomenon. Consider a patch of thephotosphere with an area of 5.10 × 1014 m2. Its emissivity is 0.965.a) Find the power it radiates if its temperature is uniformly 5800oK,corresponding to the quiet Sun.b) To represent a sunspot, assume 10.0% of the patch area is at4800oK and the other 90.0% is at 5890oK. Find the poweroutput of the patch.
Consider an ideal gas enclosed in a spectral tube. When a high voltage is placed across the tube, many atoms are excited, and all excited atoms emit electromagnetic radiation at characteristic frequencies. According to the Doppler effect, the frequencies observed in the laboratory depend on the velocity of the emitting atom. The nonrelativistic Doppler shift of radiation emitted in the x direction is f = f0(1 + vx / c). The resulting wavelengths observed in the spectroscope are spread to higher and lower values because of the (respectively) lower and higher frequencies, corresponding to negative and positive values of vx. We say that the spectral line has been Doppler broadened. This is what allows us to see the lines easily in the spectroscope, because the Heisenberg uncertainty principle does not cause signifi cant line broadening in atomic transitions. (a) What is the mean frequency of the radiation observed in the spectroscope? (b) To get an idea of how much the spectral line is…