Question

In: Mechanical Engineering

The inner and outer surface temperatures of a glass window 5 mm thick are 15 and...

The inner and outer surface temperatures of a glass window 5 mm thick are 15 and 5°C. The thermal resist- ance of the glass window due to conduction is Rt,cond = 1.19 × 10−3 K/W. What is the rate of heat loss through a 1 m × 3 m window? What is the thermal conductivity of the glass?

Solutions

Expert Solution

Assumption: 1. One dimensional heat flow i.e heat is flowing only in a direction perpendicular to the cross sectional area.

2. Temperatures on both surfaces of the walls are uniform.

The heat loss due to conduction through a wall is given by Fourier's law of heat conduction.

It is given as,

Where,

K = thermal conductivity

A = Area of cross section through which heat is being conducted.

= Temperature difference between two surfaces

L = Thickness of the wall

Using electrical analogy, we can rewrite Fourier's law as follows,

Rth = Thermal resistance analogous to electrical resistance and analogous to potential difference.

It is given that,

Finding heat loss,


Related Solutions

The inner surface of a 5 cm diameter, 3 mm thick, and 7 cm high styrofoam...
The inner surface of a 5 cm diameter, 3 mm thick, and 7 cm high styrofoam cup is at 70 °C. the outer surface is exposed to air at 20 °C. the surface heat transfer coefficient associated with the outer surface is 8 w/m2 °C. Determine The heat transfer rate through the cylindrical surface of the cup. The outer surface temperature of the cup.
A double pane window consists of two pieces of glass each of 8 mm thick that...
A double pane window consists of two pieces of glass each of 8 mm thick that enclose an air space of 8 mm thick. The window separates room air at 18°C from outside ambient air at -8°C. The convection coefficient associated with the inner (room-side) surface is 12W/m2 .K. The thermal conductivity of the glass is kg=1.35 W/m. K and that of the air is ka=0.027 W/m. K Q1- If the outside air convection coefficient is ho = 76 W/m2...
A double pane window consists of two pieces of glass each of 8 mm thick that...
A double pane window consists of two pieces of glass each of 8 mm thick that enclose an air space of 8 mm thick. The window separates room air at 18°C from outside ambient air at -8°C. The convection coefficient associated with the inner (room-side) surface is 12W/m2 .K. The thermal conductivity of the glass is kg=1.35 W/m. K and that of the air is ka=0.027 W/m. K Q1- If the outside air convection coefficient is ho = 76 W/m2...
The variation of the spectral transmissivity of a 0.6cm thick glass window is 0.92 in the...
The variation of the spectral transmissivity of a 0.6cm thick glass window is 0.92 in the wavelength range from 0.3-3micrometer. Determine the average transmissvity of this window for solar radiation at T=5800K. Also, determine the amount of solar radiation transmitted through the window for incident solar radiation of 650W/m2.
3. Assume an annulus of inner radius r1 and outer radius r2. The inner surface is...
3. Assume an annulus of inner radius r1 and outer radius r2. The inner surface is at T1, the outer surface at T2, T1 > T2. Assume heat transfer between the surfaces by conduction, with a variable conductivity, k = a + bT, develop an expression for the temperature in the material of the annulus.
A disk with outer radius ro = 150 mm and inner radius ri = 25 mm...
A disk with outer radius ro = 150 mm and inner radius ri = 25 mm is press-fitted onto a shaft of radius 25.075 mm. Both members are steel with Young’s modulus, E = 205 GPa, Poisson’s ratio, ? = 0.29, and density, ? = 7845 kg·m-3. Determine and plot the radial and tangential stress distributions in the disk and shaft when it is rotating at 5000 rpm. Under the above conditions, what is the magnitude of the Von Mises...
Consider an aluminum annular disk with an outer radius 63.2 mm and inner radius 7.9 mm....
Consider an aluminum annular disk with an outer radius 63.2 mm and inner radius 7.9 mm. The mass of the disk is 464 grams (HINT: the parameters of the disk are the same as in the previous pre-lab). The disk is allowed to rotate on a frictionless table with the rotation axis at its center. The disk has a small pulley rigidly mounted at the top concentrically. The pulley's radius is 12.1 mm, and the mass of the pulley is...
Two 15-cm-diameter metal disks separated by a 0.69-mm-thick piece of Pyrex glass are charged to a...
Two 15-cm-diameter metal disks separated by a 0.69-mm-thick piece of Pyrex glass are charged to a potential difference of 1100 V . What is the surface charge density on the disks? What is the surface charge density on the glass?
A current of 5 mA flows through a 2 mm inner-diameter glass tube filled with 1.0...
A current of 5 mA flows through a 2 mm inner-diameter glass tube filled with 1.0 mol dm-3 NaCl(aq) solution in the anode compartment in addition to a CH3COONa (aq) solution in the cathode compartment. The boundary created between the two solutions moves 6.05 mm towards the anode in 10 minutes. Calculate the transport number of the chloride ion in the solution.
A long, hollow, cylindrical conductor (inner radius 2.4 mm, outer radius 4.4 mm) carries a current...
A long, hollow, cylindrical conductor (inner radius 2.4 mm, outer radius 4.4 mm) carries a current of 45 A distributed uniformly across its cross section. A long thin wire that is coaxial with the cylinder carries a current of 24 A in the opposite direction. What is the magnitude of the magnetic field (a) 1.4 mm, (b) 2.6 mm, and(c) 4.7 mm from the central axis of the wire and cylinder?
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT