Question

**The temperature outside is -10 C . You have a heat pump
that can deliver 2kW of heat to your room. The only heat transfer
occurs through a glass window which has an area of 5.1m2, a
thickness of 1.3mm and a thermal conductivity of 0..8W/mK. Given
that the room has no curtains, your room is otherwise well
insulated and the outside temperature stays the same, what is the
highest temperature that the room will reach.**

Answer #1

We know that Heat transfer rate due to conduction is given by:

H = Q/t = k*A*dT/dx

dT = change in temperature = H*dx/(k*A)

H = Power delivered = 2 kW = 2000 W

dx = thickness of glass window = 1.3 mm = 1.3*10^-3 m

k = thermal conductivity = 0.8 W/m.K

A = Area of window = 5.1 m^2

So,

dT = 2000*1.3*10^-3/(0.8*5.1)

dT = 0.63725 C

T_in - T_out = 0.64

T_in = T_out + 0.64

T_in = max temperature inside room = -10 + 0.64

**T_in = -9.36 C**

**Let me know if you've any query.**

Suppose you are sitting, naked, on a steel bench with a
temperature of 10°C. The only thing insulating the core of your
body (temperature 37°C) is a layer of skin (the epidermis and
dermis together are about 4 mm thick) and fat (varies from
individual to individual, but a typical thickness on the buttocks
and the back of the thighs might be 1.0 cm.) Estimate the rate of
heat loss by conduction under this circumstance.
I estimated the area of...

(a)
Calculate the rate of heat conduction (in W) through house walls
that are 15.0 cm thick and that have an average thermal
conductivity twice that of glass wool. Assume there are no windows
or doors. The surface area of the walls is 115 m2 and
their inside surface is at 19.0°C, while their outside surface is
at 5.00°C.
W
(b)
How many 1 kW room heaters would be needed to balance the heat
transfer due to conduction? (Round your...

Calculate the rate of heat conduction (in W) through house walls
that are 14.5 cm thick and that have an average thermal
conductivity twice that of glass wool. Assume there are no windows
or doors. The surface area of the walls is 145 m2 and
their inside surface is at 21.5°C, while their outside surface is
at 5.00°C.
How many 1 kW room heaters would be needed to balance the heat
transfer due to conduction? (Round your answer to the...

a. Discuss why car inside temperature is high when you park the
car outside in a sunny day even under the shade and the relation
with glass transmissivity (Greenhouse effect). [5 marks]
b. A double walled spherical tank is used to store iced water at
O'C. The tank internal diameter is 2 m and wall thickness is 0.5
cm. The inner and outer walls are separated with the 2 cm thick
space. The air between the two walls of the...

Temperatures of gases inside the combustion chamber of a
four‑stroke automobile engine can reach up to 1000 ∘C. To remove
this enormous amount of heat, the engine utilizes a closed
liquid‑cooled system that relies on conduction to transfer heat
from the engine block into the liquid and then into the atmosphere
by flowing coolant around the outside surface of each cylinder.
Suppose that, in a particular 6‑cylinder engine, each cylinder
has a diameter of 8.75 cm, a height of 11.0...

A hot cup of black coffee (85°C) is placed on a tabletop (22°C)
where it remains. The surrounding room is at a temperature of 22°C.
The cup is cylindrical in shape with a height of 15.0 cm and an
outside diameter of 8.00 cm. The cup is made of ceramic with a
thermal conductivity of 0.84 W/m°C. The outside of the cup has a
temperature of 60°C and the cup is 6.0 mm in thickness. A slight
breeze is blowing...

Temperatures of gases inside the combustion chamber of a
four-stroke automobile engine can reach up to 1000°C. To remove
this enormous amount of heat, the engine utilizes a closed
liquid-cooled system which relies on conduction to transfer heat
from the engine block into the liquid and then into the atmosphere
by flowing coolant around the outside surface of each cylinder.
Assume you have a 6-cylinder engine, and each cylinder has a
diameter of 9.00 cm and height of 11.6 cm...

A water drop slung onto a skillet with a temperature between 100°C
and 200°C will remain a liquid for about 1 second. However, if the
skillet is much hotter the drop can last several minutes. This is
due to the Leidenfrost Effect, named after an early investigator
(circa 1756). The longer lifetime is due to the support of a thin
layer of air and water vapor that separates the drop from the metal
(by a distance L, as shown in...

You are working for a camping gear manufacturer and your boss
has asked you to design a new portable cooler. The portable cooler
will have the shape of a rectangular prism, with a height of 25 cm,
a width of 20 cm and a length of 35 cm. The walls of the cooler
will be composed of a thin inner liner (negligible resistance to
heat transfer), a gap containing water, and an outer insulating
wall having a thickness of 20...

Sign In
INNOVATION
Deep Change: How Operational Innovation Can Transform Your
Company
by
Michael Hammer
From the April 2004 Issue
Save
Share
8.95
In 1991, Progressive Insurance, an automobile insurer based in
Mayfield Village, Ohio, had approximately $1.3 billion in sales. By
2002, that figure had grown to $9.5 billion. What fashionable
strategies did Progressive employ to achieve sevenfold growth in
just over a decade? Was it positioned in a high-growth industry?
Hardly. Auto insurance is a mature, 100-year-old industry...

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 2 minutes ago

asked 4 minutes ago

asked 4 minutes ago

asked 9 minutes ago

asked 16 minutes ago

asked 24 minutes ago

asked 24 minutes ago

asked 37 minutes ago

asked 46 minutes ago

asked 56 minutes ago

asked 1 hour ago

asked 1 hour ago