2 of 4I Review I Constants I Periodic TableIn this problem you will estimate the heat lost by atypical house, assuming that the temperature insideis Tin = 20°C and the temperature outside isTout = 0°C. The walls and uppermost ceiling of atypical house are supported by 2 × 6-inch woodenbeams (kwood = 0.12 W/(mK)) with fiberglassinsulation (kins = 0.04 W/(mK)) in between.The true depth of the beams is actually 5.625inches, but we will take the thickness of the wallsand ceiling to be Lwall = 18 cm to allow for theinterior and exterior covering. Assume that thehouse is a cube of length L= 9.0 m on a side.Assume that the roof has very high conductivity, sothat the air in the attic is at the same temperaturePart AHow much heat per second H (= Q/AT) is lost from the house due to heat conduction?Give your answer in watts, rounding to the nearest 10 W.» View Available Hint(s)Πν ΑΣφas the outside air. Ignore heat loss through theground. The effective thermal conductivity of thewall (or ceiling) keff, is the area-weighted averageof the thermal conductivities of the wooden beamsH =Wand the fiberglass insulation that make up each ofthem. Allowing for the fact that the 2 × 6 beamsare actually only 1.625 inches wide and arespaced 16 inches center to center, a calculation ofthis conductivity for the walls yieldskeff = 0.048 W/(mK). For simplicity, assumethat the ceiling also has the same value of keff -SubmitPart BLet us assume that the winter consists of 150 days in which the outside temperature is 0° C. This will give the typicalnumber of "heating degree days" observed in a winter along the northeastern US seaboard. (The cumulative number ofheating degree days is given daily by the National Weather Service and is used by oil companies to determine when theyshould fill the tanks of their customers.) Given that a gallon (3.4 kg) of oil liberates Qg = 1.4 x 10° J when burned, howmuch oil will be needed to supply the heat lost by conduction from this house over a winter? Assume that the heatingsystem is 75% efficient.Give your answer numerically in gallons to two significant figures.• View Available Hint(s)gallons per winterGallons consumed =MacBook PrO

Given data, Inside temperature of the house, Tin = 20 °C Outside temperature of the house, Tout = 0…

Answered: In this problem you will estimate the…

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

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A pipe of length L connects to thermal reservoirs that are kept constant at temperatures T₁ and T₂. The pipe contains a gas with a thermal conductivity K, a density p, and a heat capacity cp. What is the temperature T of the gas in the tube at a distance x = 0.2L away from the thermal reservoir with temperature T₁ ? Select one: a. b. T = 0.5(T₁+T₂) T = T₁ +0.2 (T₂-T₁) c. T = T₁ +0.2(T₂-T₁) d. T = T₁ +0.2(T₁ - T₂)
Steel pipe (outer diameter 100 mm) is covered with two layers of insulation. The inner layer, 40 mm thick, has a thermal conductivity of 0.07 W / (m K). The outer layer, 20 mm thick, has a thermal conductivity of 0.15 W / (m K). Pipes are used to deliver steam with a pressure of 500 kPa. The temperature on the outer insulation surface is 24 ° C. If the pipe is 12 m long, determine the following: (assuming that the conduction heat transfer resistance of the steel pipe and the vapor convection resistance are negligible). a. Heat loss per hour. = Answer kJ / hour. b. Temperature between insulation layers. = Answer ° C.
Q: Consider the section of wall as shown in the figure, assuming one dimensional heat flow, determine the following: I- Rate of heat transfer per unit area (Im²) through the composite wall. II- Determine also the temperature (Tp) as shown in the figure. To1 30 °C Too2 = 2 °C hi = 20 W/m?.C 8 cm h2 = 12 w/m?.C 20 cm A %3D kA = 0.6 W/m.°C D TD %3D 30 cm kB = 0.8 W/m .°C T01 To2 kC = 0.9 W/m.°C hi B E 10 cm h2 kD = 0.7 W/m .°C kE = 0.5 W/m.°C %3D kF = 0.04 W/m.C 8 cm 6cm. 12cm
Insulating material is used to reduce heat loss from the heating furnace walls to the room. The surface temperature of the insulating material is 100 ° C and the other surfaces 20 ° C. Allowable heat loss up to 140 W / m2 from the wall. If the thermal conductivity of the insulation material is 0.05 W / (m ° C), calculate the required thickness of insulation. insulation thickness = Answer cm
Steel pipe (outer diameter 100 mm) is covered with two layers of insulation. The inner layer, 40 mm thick, has a thermal conductivity of 0.07 W / (m K). The outer layer, 20 mm thick, has a thermal conductivity of 0.15 W / (m K). Pipes are used to deliver steam with a pressure of 700 kPa. The temperature on the outer insulation surface is 24 ° C. If the pipe is 12 m long, determine the following: (assuming that the conduction heat transfer resistance of the steel pipe and the vapor convection resistance are negligible). a. Heat loss per hour. = Answer kJ / hour. b. Temperature between insulation layers. = Answer ° C.
There is a 1.20-cm-thick stagnant air pocket. A) What thickness of cork would have the same R-factor as the stagnant air pocket? The thermal conductivity of air is 0.0230 W/m·K and of cork is 0.0460 W/m·K.in cm B) What thickness of tin would be required for the same R-factor as a 1.20-cm-thick stagnant air pocket? The thermal conductivity of air is 0.0230 W/m·K and of tin is 66.8 W/m·K . in m i asked how to do this but got the wrong soloution
You are designing a 3m x 3m floor with radiant heating. The floor has 12 parallel pex pipes (k = 40 W/mK) of L = 3m, OD = 25mm and ID = 20mm. Hot water (TInfintiy 1 = 90oC, h = 200 W/m2K) runs through the pipes continuously. The surface below the pipes is perfectly insulated. Above the pipes, there is a 3mm layer of bonding material (? = 12 W/mK) and a 9mm layer of tile (k = 2 W/mK). Above the tile, there is air (TInfinity 2 = 25oC, h = 20 W/m2K). Properties of Air: k = 0.025 W/mK, Pr = 0.72, v = 1.847 x 10−5, u = 16.84 x 10−6, p = 1.2 kg/m3, B = 1/Tf (ideal gas), Hint: Assume that the “layer” of pipe starts at the center point (e.g. for conduction purposes, the pipe is OD divided by 2 thick). For convection, consider the entire pipe surface. a) What is the total heat rate entering the room above the floor? b) What is the temperature of the top of the tile?
1) A wall section composed from the outside to inside, of concrete brick 100mm thick, an air space of 50mm, two layers of fiberglass insulation 38mm thick, concrete block 150mm thick and air space of 19mm and a gypsum board of 13mm. The exterior conditions are -20C and RH=90% while the interior conditions are 23C and RH=40%. The surface temperature from the outside to inside are shown in the figure. The permeances are: Still Air: µ = 175 ng/pa.s.m Fiber glass: M=2560 ng/pa.s.m? Concrete block: M= 200 ng/pa.s.m? Gypsum board: M= 2000 ng/pa.s.m? Concrete brick: µ = 4.55 ng/pa.s.m Determine if there is a risk of condensation, and if there is, what is the condensation rate? What would happen if a vapor barrier (M=0.2 ng/pa.s.m²) was installed on the warm side of the insulation (Surface 4). 21с 19C 16 С 12C -10 -15C -18C -19C Gyp Air Concrete Fiber Fiber Air Concrete Outdoor Indoor sum block Glass Glass brick 230 19 50 mm -20C 13 150 mm 38 mm | 38 mm 100 mm RH=90% RH=40% mm mm Surf. 1 Surf.…
Steel pipe (outer diameter 100 mm) is covered with two layers of insulation. The inner layer, 40 mm thick, has a thermal conductivity of 0.07 W / (m K). The outer layer, 20 mm thick, has a thermal conductivity of 0.15 W / (m K). Pipes are used to deliver steam with a pressure of 800 kPa. The temperature on the outer insulation surface is 24 ° C. If the pipe is 10 m long, determine the following: (assuming that the conduction heat transfer resistance of the steel pipe and the vapor convection resistance are negligible). a. Heat loss per hour. = Answer kJ / hour. b. Temperature between insulation layers. = Answer ° C.
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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
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

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