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°KTni = 20°C| h. = 60 W/m²KTeo =-15°CFiberglassL=10 cmPlaster boardk= 0.04 W/mKL=1 cmk = 0.15 W/mKPlywoodL-2 cmk= 0.13 W/mKFigure 2.1(i) Represent the composite wall by a thermal circuit, and label all the components in the circuitii) Determine the inner surface temperature of the house.

Answered: Image /qna-images/answer/f158879e-982c-4e20-a7bb-8c1144617f27.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

As shown in the sketh below, a steam pipe of 0.12-m inside diameter is insulated with a layer of calcium silicate. 1. Ts. 1} Steam 12. T8.2} Insulation (a) If the insulation is 27.5 mm thick and its inner and outer surfaces are maintained at T1 = 800 K and T2 = 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 (q'), in W/m, and outer surface temperature T2, in K, for the steam pipe with the inner surface temperature fixed at T₁ = 800 K, inner radius r₁ = 0.06 m, and outer radius r₂ = 0.14 m. The outer surface is exposed to an airflow (To = 25°C) that maintains a convection coefficient of h = 25 W/m²-K and to large surroundings for which Tsur = To = 25°C. The surface emissivity of calcium silicate is approximately 0.8.
The left side of a composite wall is kept at 300oC constantly. The right side of the same wall is exposed to air at 20oC with a convection coefficient of 32 W/mk. kA = 10 W/mK, kB = 40 W/mK, kC = 1 W/mK, kD = 300 W/mK, kE = 0.1 W/mK Given figure 1, calculate: a) The total thermal resistance of the wall.b) The total heat rate through the wall.c) The junction temperature where B meets D (between second and third column)
Question 1 The exterior wall of a building consists of 100 mm thick face brick (k = 0.9 W/m-K), 40 mm thick polystyrene insulating board (k = 0.036 W/m-K), 125 mm thick concrete block (k = 1.8 W/m-K) and 15 %3D mm thick interior gypsum board (k = 0.18 W/m-K). The inside and outside convective heat transfer coefficients are 6.5 W/m2-K and 22.5 W/m2-K, respectively. The outside air temperature is -5°C and the inside air temperature is 20°C. The wall is 3 m high and 15 m long. Calculate the rate of heat loss (in W) through the wall. Round your answer to 2 decimal places. Add your answer Follow-up question to Question 1, calculate the temperature (in °C) of the interior surface of the wall. Round your answer to 2 decimal places. Add your answer Follow-up question to Question 1, calculate the temperature (in °C) of the exterior surface of the wall. Round your answer to 2 decimal places. Add your answer
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?
A domestic pitched roof of tiles on felt sacking with a plasterboard ceiling has an existing u-value of 1.9w/m2k. Calculate the minimum thickness of fibre glass insulation in the roof space required to give the roof a new u-value of 0.25w/m2k. The thermal conductivity of the fibre glass used is 0.04w/mk
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.
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.
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

SEE MORE QUESTIONS

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