A house has a composite wall of wood (exterior) (k = 0.12 W m-1 K -1...
A house has a composite wall of wood (exterior) (k = 0.12 W m-1 K -1 , 20 mm thick), fibreglass insulation (k = 0.045 W m-1 K -1 , 70 mm thick) and plasterboard (interior) (k = 0.25 W m-1 K -1 , 10 mm thick). Determine the total heat loss through the wall when the inside temperature is 20 °C, the outside temperature is -10 °C, the inside heat transfer coefficient is 15 W m-2 K -1, and the outside heat transfer coefficient is 65 W m2 K -1. Also, determine the temperature at the interface between the plasterboard and the insulation, assuming contact resistance is negligible.
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A house has a composite wall of wood (exterior) (k = 0.12 W m-1
K -1...
A carpenter builds an exterior house wall with a layer of wood 2.9 cm thick on...
A carpenter builds an exterior house wall with a layer of wood 2.9 cm thick on the outside and a layer of Styrofoam insulation 2.1 cm thick on the inside wall surface. The wood has k=0.080W/(m⋅K), and the Styrofoam has k= 0.010 W/(m⋅K). The interior surface temperature is 19.0 ∘C , and the exterior surface temperature is -10.0 ∘C . What is the temperature at the plane where the wood meets the Styrofoam?
1. A house has a composite wall of wood, fiberglass insulation, and plaster board, as indicated...
1. A house has a composite wall of wood, fiberglass insulation, and
plaster board, as indicated below. On a cold winter day the
convection heat transfer coefficients are ho
=
60 W/m2K
and hi
=
30 W/m2K.
The total wall surface area is 350 m2.
(a) Determine the heat transfer rate through the wall in
Watts.
(b) If the wind were blowing violently, raising ho
to 300 W/m2K,
determine the percentage
increase in the heat transfer rate.
(c) What is...
Consider the following composite wall of a building. It is made out of plaster board (Lp...
Consider the following composite wall of a building. It is made out of plaster board (Lp 0.85 W/mK), glass fibre insulation (Lb-160 mm, k = 0.050 W/mK) and plywood (1,-40 m m, k = 0.70 W/mK) as shown below. On a certain day, the convective heat transfer coefficients inside and outside of the building are 35 W/m2K and 65 W/m2 K respectively. The inside and outside temperatures are 24°C and 36°C respectively. The wall has a total surface area of...
[6] A 20-cm thick wall of a house made of brick (k = 0.72W/m. C) is...
[6] A 20-cm thick wall of a house made of brick (k = 0.72W/m. C) is subjected to inside air at 22.C with a convection heat-transfer coefficient of 15 W/m2. C. The inner surface temperature of the wall is 18 C and the outside air temperature is -1 °C. Determine the outer surface temperature of the wall and the heat-transfer coefficient at the outer surface.
A house has a composite wall of wood, fiberglass insulation, and plaster board, as indicated in...
A house has a composite wall of wood, fiberglass insulation, and
plaster board, as indicated in the sketch. On a cold day, the
temperature and the convection heat transfer coefficients are T∞,i
=20°C, hi =30 W/m2K and T∞,o=−15°C, ho =60 W/m2K. The wall surface
area is 350 m2. Determine the total heat loss through the wall.
Conductivities are given as b k =0.038 W/m.K, s k =0.012 W/m.K, p k
=0.17 W/m.K
Glass fiber blanket (28 kg/m3), kn Plaster board,...
2.) A plane wall is made of brick with a thermal conductivity of 1.5 W/(m-K). The...
2.) A plane wall is made of brick with a thermal conductivity of 1.5 W/(m-K). The wall is 20 cm thick and has a surface area of 10 m2. One side of the wall is exposed to outside air blowing against the wall resulting in a heat transfer coefficient of 20 W/(m2-K). The other side is exposed to an air-conditioned room with a convective heat transfer coefficient of 5 W/(m2-K). a. What are the thermal resistances corresponding to conduction through...
The wall of a house is 3 m high, 10 m long and 30 cm thick;...
The wall of a house is 3 m high, 10 m long and 30 cm thick; it has an effective thermal conductivity of 10 W/m K. The outer surface of the wall has an emissivity of 0.75. On a winter night, the outer surface of this wall is at a temperature of 0 °C and the air is at a temperature of –10 °C. The heat transfer coefficient for the outside wall is 8 W/m2 K. The outside wall also...
Problem : A cryogenic flui d is flowing in a 304 SS pipe. The pipe is...
Problem
:
A cryogenic flui
d is flowing in a
304 SS
pipe.
The pipe is insulated
on its outside surface
with
6
-
mm thick,
evacuated,
aluminum foil/glass mat insulation.
(“Evacuated” means a partial vacuum is drawn on the
insulation to
remove air that would otherwise fill
pores inside the insulation.)
The pipe
inside diameter
is 127 mm; it’s outside diameter is 138 mm.
The
fluid temperature is
-
173
o
C
.
T
he
air temperature
outside the...
An exterior wall of a house made in three layers (brick (layer 1) + loosely packed...
An exterior wall of a house made in three layers (brick (layer 1) + loosely packed rock (layer 2) + gypsum plaster (layer 3)) may be approximated by a L1=10 cm layer of common brick k1=0.7 W/m℃ and a L3=4 cm layer of gypsum plaster k3=1.07 W/m℃. The total wall surface A=55 m2. The thickness L2 of loosely packed rock-wool insulation k2=0.65 W/m℃. The outlet temperature To=45℃, the inner temperature Ti=22℃, The internal wall temperature T1=27℃ . The heat transfer...
For such aircraft application (Figure 3), a wall is made from insulation material (k-0.030 W/m.K) and...
For such aircraft application (Figure 3), a wall is made from insulation material (k-0.030 W/m.K) and the insulation material is mounted between four layers of carbon steel (2 mm thickness), the carbon layers are separated by a 2 mm air gap (kair-0.025 W/mK). Figure 3, the thermal conductivity of the carbon steel is (k-15.5 W/m.K). The temperature inside the wall is maintained at 6 °C. The environmental temperature is 24°C. The engineer would like to avoid condensation occurring at outer...
1. A house has a composite wall of wood, fiberglass insulation, and
plaster board, as indicated below. On a cold winter day the
convection heat transfer coefficients are ho
=
60 W/m2K
and hi
=
30 W/m2K.
The total wall surface area is 350 m2.
(a) Determine the heat transfer rate through the wall in
Watts.
(b) If the wind were blowing violently, raising ho
to 300 W/m2K,
determine the percentage
increase in the heat transfer rate.
(c) What is...
Consider the following composite wall of a building. It is made out of plaster board (Lp 0.85 W/mK), glass fibre insulation (Lb-160 mm, k = 0.050 W/mK) and plywood (1,-40 m m, k = 0.70 W/mK) as shown below. On a certain day, the convective heat transfer coefficients inside and outside of the building are 35 W/m2K and 65 W/m2 K respectively. The inside and outside temperatures are 24°C and 36°C respectively. The wall has a total surface area of...
[6] A 20-cm thick wall of a house made of brick (k = 0.72W/m. C) is subjected to inside air at 22.C with a convection heat-transfer coefficient of 15 W/m2. C. The inner surface temperature of the wall is 18 C and the outside air temperature is -1 °C. Determine the outer surface temperature of the wall and the heat-transfer coefficient at the outer surface.
A house has a composite wall of wood, fiberglass insulation, and
plaster board, as indicated in the sketch. On a cold day, the
temperature and the convection heat transfer coefficients are T∞,i
=20°C, hi =30 W/m2K and T∞,o=−15°C, ho =60 W/m2K. The wall surface
area is 350 m2. Determine the total heat loss through the wall.
Conductivities are given as b k =0.038 W/m.K, s k =0.012 W/m.K, p k
=0.17 W/m.K
Glass fiber blanket (28 kg/m3), kn Plaster board,...
2.) A plane wall is made of brick with a thermal conductivity of 1.5 W/(m-K). The wall is 20 cm thick and has a surface area of 10 m2. One side of the wall is exposed to outside air blowing against the wall resulting in a heat transfer coefficient of 20 W/(m2-K). The other side is exposed to an air-conditioned room with a convective heat transfer coefficient of 5 W/(m2-K). a. What are the thermal resistances corresponding to conduction through...
Problem
:
A cryogenic flui
d is flowing in a
304 SS
pipe.
The pipe is insulated
on its outside surface
with
6
-
mm thick,
evacuated,
aluminum foil/glass mat insulation.
(“Evacuated” means a partial vacuum is drawn on the
insulation to
remove air that would otherwise fill
pores inside the insulation.)
The pipe
inside diameter
is 127 mm; it’s outside diameter is 138 mm.
The
fluid temperature is
-
173
o
C
.
T
he
air temperature
outside the...
For such aircraft application (Figure 3), a wall is made from insulation material (k-0.030 W/m.K) and the insulation material is mounted between four layers of carbon steel (2 mm thickness), the carbon layers are separated by a 2 mm air gap (kair-0.025 W/mK). Figure 3, the thermal conductivity of the carbon steel is (k-15.5 W/m.K). The temperature inside the wall is maintained at 6 °C. The environmental temperature is 24°C. The engineer would like to avoid condensation occurring at outer...
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