A house has a composite wall of wood, fiberglass insulation and plaster board,as indicated in Figure 2.1. The total wall surface area is 300 m²'h = 30 W/m*KTai = 20°Ch. = 60 W/m°KTra--15°CFiberglassL=10 cmk= 0.04 W/mKPlaster boardPlywoodL-2 cmk= 0.13 W/mKL=1 cmk= 0.15 W/mKFigure 2.1(i) Determine the total heat transfer rate, Q through the wall

Answered: Image /qna-images/answer/11da71ab-e987-4c71-9bd4-3fc4f658cb0d.jpg

Answered: A house has a composite wall of wood,…

Elements Of Electromagnetics

7th Edition

ISBN:9780190698614

Author:Sadiku, Matthew N. O.

Publisher:Sadiku, Matthew N. O.

ChapterMA: Math Assessment

Section: Chapter Questions

Problem 1.1MA

See similar textbooks

Similar questions

The inside wall of a furnace is at 2100oF and the outside wall is at 300oF. The wall of a furnace must be designed to transmit no more than 220 Btu/hr-ft2. Two types of bricks are available for construction:TYPE A: k = 0.38 Btu/ hr-ft-R with an allowable maximum temperature of 1400oFTYPE B: k = 0.98 Btu/ hr-ft-R with an allowable maximum temperature of 2300oF Both types of bricks have the same dimensions (9” x 4.5” x 3”) but the cost for Type B brick is twice the cost of Type A brick. Illustrate the order of arrangement of bricks A and B in the furnace wall (with thickness, estimated temperatures at the interface between walls A and B and at the interior and exterior surface, the transport area and direction of transfer included)
A boiler furnace wall must have a heat loss no greater than 700 Btu/hr~ft2 and is madeof a material with a thermal conductivity of 0.60 Btu/hr~ft~F. The inner wall surfacetemperature is '2000°F, and the outer surface temperature is 800°F. What wall thick~ness is required?
As shown in the sketh below, a steam pipe of 0.12-m inside diameter is insulated with a layer of calcium silicate. "2. Ta2} 1. Ta,1} Steam Insulation (a) If the insulation is 10 mm thick and its inner and outer surfaces are maintained at T, = 800 K and Ta = 490 K. respectively,. what is the rate of heat loss per unit length (q) of the pipe, in W/m? (b) Determine the rate of heat loss per unit length (d), in W/m, and outer surface temperature T,2, in K, for the steam pipe with the Inner surface temperature fixed at T = 800 K, inner radius = 0.06 m, and outer radius n = 0.18 m. The outer surface is exposed to an airflow (T 25°C) that maintains a convection coefficient of h = 25 W/m2-K and to large surroundings for which Tur = T, = 25°C. The surface emissivity of calcium silicate is approximately 0.8.
1 example each Conductive heat flow through flat surface Conductive heat flow throw composite wall
2. Calculate Passive House's energy demand. a, Calculate window U-value based on given data in figure. 0.117m 0.117m 0.134m C₂ Utotal Wglass-0.996m = 1.229m glass Uglass = 0.6- glass W window - 123m W m².c 0.117m 1.48m nwindow W m² °C Uframe = 1.6- Area₁ U₁ + Area2 U₂... + Area, * U₁ Area total b. With the calculated U value for the windows find out how much power needed to maintain 20°C in a home with outside of 0°C based on the following: the house having a square footprint 17 m by 17 m, walls 2.5 m high (Uwalls = 0.152 each of the four walls hosting two windows, and each window having an area of 2 m². The entry door area is 2.5 m² (Udoor = 0.65- ). What are the heat loss rates for the installed windows, the door, the walls, the ceiling, and the floor? What is the overall heat loss rate of the home? m². C 1. What do these calculated heat loss rate values mean? 2. What is the definition of the passive house? 3. What does the U-value represent? Use its unit as a hint and describe it…
A slab of thickness L = 0.1 m and of thermal conductivity k = 1 W/mK has the temperature distribution as T(x) = ax2 + bx + c. The boundary conditions; insulation at at x = L and a 100 W/m2 constant heat flux at x = 0. What is the temperature at the insulated surface if c = 5 °C?
Find the thermal resistance r (in hr - °F/BTU) and the equivalent R-value (in hr ft?. °F/BTU) of a typical frame 20' x 7.5" wall consisting of a 0.5" plaster board on the inside of the room, nominai 2 x 4 studs, and a 0.5" sheathing on the outside. The spaces between the studs are filled with an R-15 insulating foam. What is the heat loss (in BTU) through this wall in four hours if the inside temperature is 72°F and the outside temperature is 32°F? (Assume that the 15% of the wall's area are studs and the remaining 85% is filled with the insulating foam. Assume that the air is moving outside the wall.) r= 0.0805 x hr: OF/BTU R=0.09 x hr ft2. F/BTU AQ = BTU
The fin shown in Figure is insulated on the perimeter. The left end has a constant temperature of 100 °C. A positive heat flux of q = 5000 W/m² acts on the right end. Let Ky = 10 W/(m °C) and cross-sectional area A = 0.1 m2 Determine the temperatures at L/4, L/2, 3L/4, and L, where L = 0.8 m. 4-0.1 m T-100 C 5000 W/m
(C) The composite wall of a refrigerator consists of three different materials; A, B, and C. Two of the used materials have known thermal conductivity, ka = 30 W/m. K and kc=45 W/m. K, and known thickness, LA=0.20 m and Lc = 0.15 m. The third material, B, which is sandwiched between materials A and C, is of known thickness, LB = 0.15 m, but unknown thermal conductivity kB. Under steady-state operating conditions, measurements reveal an outer surface temperature of Ts,0 = 20°C, an inner surface temperature of Ts,i = 600°C, and a refrigerator air temperature of To∞ = 800°C. The inside convection coefficient h is known to be 25 W/m?.K. What is the value of thermal conductivity for material B? T -T kg kc s, o kA Air T, h LA Figure 2: Composite wall configuration described in part C.
A house has a composite wall of wood, fiberglass insulation and plaster board, as indicated in Figure 2.1. The total wall surface area is 300 m²" h = 30 W/m°K Tni = 20°C | h. = 60 W/m²K Teo =-15°C Fiberglass L=10 cm Plaster board k= 0.04 W/mK L=1 cm k = 0.15 W/mK Plywood L-2 cm k= 0.13 W/mK Figure 2.1 (i) Represent the composite wall by a thermal circuit, and label all the components in the circuit ii) Determine the inner surface temperature of the house.
A square steel bar of side length w = 0.21 m has a thermal conductivity of k = 15.6 J/(s⋅m⋅°C) and is L = 2.7 m long. One end is placed near a blowtorch so that the temperature is T1 = 95° C while the other end rests on a block of ice so that the temperature is a constant T2. a. input an expression for the heat transferred to the cold end of the bar as a function of time using A=w^2 as the cross-sectional area of the bar. b. how much energy in joules was conducted in 1 hour, assuming t2=0*C c. input an expression for the mass of the water melted in one hour using Q1 from above and Lf in the latent heat of fusion. mw=
3-52 A 4-m-high and 6-m-wide wall consists of a long 18-cm X 30-cm cross section of horizontal bricks (k = 0.72 W/m . °C) separated by 3-cm-thick plaster layers (k = 0.22 W/m . °C). There are also 2-cm-thick plaster layers on each side of the wall, and a 2-cm-thick rigid foam (k = 0.026 W/m - °C) on the inner side of the wall. The indoor and the outdoor temperatures are 22°C and −4°C, and the convec- tion heat transfer coefficients on the inner and the outer sides are h₁ = 10 W/m² . °℃ and h₂ = 20 W/m². °C, respectively. Assuming one-dimensional heat transfer and disregarding radi- ation, determine the rate of heat transfer through the wall. Foam Plaster Brick 1+₂+18 2 FIGURE P3-52 18 cm N 1.5 cm 30 cm 1.5 cm

Recommended textbooks for you

Elements Of Electromagnetics

Mechanical Engineering

ISBN:

9780190698614

Author:

Sadiku, Matthew N. O.

Publisher:

Oxford University Press

Mechanics of Materials (10th Edition)

Mechanical Engineering

ISBN:

9780134319650

Author:

Russell C. Hibbeler

Publisher:

PEARSON

Thermodynamics: An Engineering Approach

Mechanical Engineering

ISBN:

9781259822674

Author:

Yunus A. Cengel Dr., Michael A. Boles

Publisher:

McGraw-Hill Education

Elements Of Electromagnetics

Mechanical Engineering

ISBN:

9780190698614

Author:

Sadiku, Matthew N. O.

Publisher:

Oxford University Press

Mechanics of Materials (10th Edition)

Mechanical Engineering

ISBN:

9780134319650

Author:

Russell C. Hibbeler

Publisher:

PEARSON

Thermodynamics: An Engineering Approach

Mechanical Engineering

ISBN:

9781259822674

Author:

Yunus A. Cengel Dr., Michael A. Boles

Publisher:

McGraw-Hill Education

Control Systems Engineering

Mechanical Engineering

ISBN:

9781118170519

Author:

Norman S. Nise

Publisher:

WILEY

Mechanics of Materials (MindTap Course List)

Mechanical Engineering

ISBN:

9781337093347

Author:

Barry J. Goodno, James M. Gere

Publisher:

Cengage Learning

Engineering Mechanics: Statics

Mechanical Engineering

ISBN:

9781118807330

Author:

James L. Meriam, L. G. Kraige, J. N. Bolton

Publisher:

WILEY

SEE MORE TEXTBOOKS