The roof of a house consists of a 18-cm-thick concrete slab (k=2 W/m·C) that is 15 m wide and 20 m long. The convection heat transfer coefficients on the inner and outer surfaces of the roof are 5 and 12W/m^2·C, respectively. On a clear winter night, the ambient air is reported to be at 10°C, while the night sky temperature is 100 K. The house and the interior surfaces of the wall are maintained at a constant temperature of 20°C. The emissivity of both surfaces of the concrete roof is 0.9. Considering both radiation and convection heat transfers, determine the rate of heat transfer through the roof, if the inner surface temperature is 7 deg Celcius. (answer in W)

Q: How does transient heat transfer differ from steady heat transfer? How does one-dimensional heat…

A:

Q: The inner and outer surfaces of a 0.5-cm thick 2-m x 2-m window glass in winter are 10°C and 3°C,…

A: Calculate the area of window glass. Calculate the rate of heat transfer through the glass by…

Q: During a visit to a plastic sheeting plant, it was observed that a 60-m-long section of a 2-in…

A: Write the given information. Write the expression of the film temperature. Write the properties of…

Q: A 50-m-long section of a steam pipe whose outer diameter is 10 cm passes through an open space at…

A:

Q: A 50-meter-long cast iron pipe with a 10-centimeter outside diameter goes through a 288 K…

A:

Q: A long 9 cm-diameter steam pipe whose external surface temperature is 70 0C passes through some open…

A:

Q: Clothing made of several thin layers of fabric with trapped air in between, often called ski…

A: Consider the thermal circuit shown below for the 5 layered jacket. Here, The total resistance for…

Q: In a new residential project, you strongly believe that double-paned windows are ‘better’ than…

A:

Q: Calculate the thermal resistance due to convection for the following situations:a. w arm water with…

A: Given Data: a. w arm water with h = 200 W⁄m2 .Kb. warm air with h = 10 W⁄m2 .Kc. warm moving air…

Q: A long 10-cm-diameter steam pipe whose external surface temperature is 110°C passes through some…

A: In order to proceed with the problems some assumptions need to be considered. Steady operating…

Q: A 40-cm-long, 0.6-cm-diameter electric resistance wire is used to determine the convection heat…

A: Giiven A 40-cm-long, 0.6-cm-diameter the convection heat transfer coefficient = 254 surface…

Q: A10-m-long section of a 6-cm-diameter horizontal hot water pipe passes through a large room whose…

A:

Q: In a new residential project, you strongly believe that double-paned windows are ‘better’ than…

A: Heat transfer Heat transfer is the phenomena in which heat energy is transfer from high temperature…

Q: What are the mechanisms of heat transfer? How are they distinguished from each other?

A: There are three mechanisms of heat transfer. These are given as under, (1) Conduction (2) Convection…

Q: A heating system is to be designed to keep the wings of an aircraft cruising at a velocity of 900…

A:

Q: A 5 m long section of a steam pipe whose outer diameter is 10 cm passes through an open space at…

A: Given data: The length of pipe, L=5 m. The diameter of the pipe, d=10 cm. The open space…

Q: A 50-meter-long cast iron pipe with a 10-centimeter outside diameter goes through a 288 K…

A:

Q: A 50 meter long cast iron pipe with outer diameter of 10 cm passes in an open space of 288 K…

A: Given,  L = 50 m d2 = 10 cm = 0.1 m To = 288 K Ti = 423 K Combined heat transfer Coefficient (h) =…

Q: Question 1 A furnace wall consisting of 0.20 m of fire clay brick. 0.15 m of kaolin, and a 0.05-m…

A:

Q: In a new residential project, you strongly believe that double-paned windows are ‘better’ than…

A: Area of window=1.5×1 m2thickness of pane=0.4 cm=0.004 mk of glass pane=0.9 wm.kIndoor…

Q: A 5-cm-external-diameter, 10-m-long hot-water pipe at 80 deg C is losing heat to the surrounding air…

A: Diameter of pipe = 5 cm Length of pipe = 10 m Pipe temperature = 80 C Surface temperature = 5 C Heat…

Q: Consider a room with a 1.8-m-high and 2.0-m-wide double- pane window consisting of two 4-mm-thick…

A: Given: T1 = 22 deg C T2 = -4 deg C There are total five resistances are acting.

Q: A long 8-cm-diameter steam pipe whose external surface temperature is 90°C passes through some open…

A: Given data diameter of the pipe D = 8 cm = 0.08m External surface temperature of the pipe Ts = 900C…

Q: Q1/ A heating system is to be designed to keep the wings of an aircraft cruising at a velocity of…

A: Given that ,  v=900km/hh=12200mT1=55.4°CP1=18.8kPa

Q: Air at 300 degrees Celsius flows over a plate of dimension 0.5 m by 0.25 m. If the convection heat…

A:

Q: A plate heated with a heat flux of 5 kW/m^2 and has an emissivity of 0.3. the air is over the plate…

A:

Q: Castor oil at 36 °C flows over a 6 m long and 1 m wide heated plate at 0.06 m/s. For a surface…

A: Given: The temperature of castor oil, To = 36 C The length of plate, L = 6 m The width of plate, b =…

Q: Consider a cold aluminum canned drink that is initially at a uniform temperature of 4°C. The can is…

A:

Q: Cold conditioned air at 12°C is flowing inside a 1.5-cm-thick square aluminum (k = 237 W/m·K) duct…

A: Given data: The given temperature of the cold conditioned air is: Ti=12 C The thickness of the…

Q: A 4-m-high and 6-m-wide wall consists of a long18-cm * 30-cm cross section of horizontal bricks (k…

A: Given data as per question Height of wall = 4 m Width of wall = 6 m Plaster thickness = 2 cm Indoor…

Q: Four power transistors, each dissipating 12 W, are mounted on a thin vertical aluminum plate 22 cm *…

A: Given data as per question No. of transistors = 4 Heat dissipated by each transistor = 12 w…

Q: Over the outside part of the room window, the wind is blowing with a speed of 10 m/sec. Due to this…

A:

Q: When is heat transfer through a fluid conduction and when is it convection? For which case is the…

A: The rate of heat transfer is given

Q: A cylindrical fuel rod of 2 cm in diameter is encased in a concentric tube and cooled by water. The…

A: Given data:

Q: An average person body surface is approximately 2.0 m². Its skin temperature is 33°C. The convection…

A: Find convective heat transfer .

Q: Hot water at an average temperature of 70°C is flowing over a 15-m section of a cast iron pipe (k =…

A: Given: Hot water temperature is 70°C. Length of pipe is 15 m. Thermal conductivity of CI pipe is 52…

Q: A Gasoline engine operating on an air standard condition has a clearance volume of 15cm^3 and a…

A: Given data Clearance volume = 15 cm³ Displacement volume = 100 cm³

Q: The temperature of a tank in the form of liquid nitrogen is -10 ° C. Tank diameter is 16 cm. The…

A: T = -10°C = 263 K D = 16 cm = 0.16 m Q/L = 65.5 W/m h = 4.35 W/m2.K e= 1

Q: The passenger compartment of a minivan traveling at 60 mph can be modeled as a 3.2-ft-high,…

A: Write the given information. Write the properties of air at 80°F.

Q: The temperature of a cylindrical tank containing liquid nitrogen is -10 ° C. Tank diameter is 16 cm.…

A:

Q: Consider a person standing in a breezy room at 20°C. Determine the total rate of heat transfer from…

A: Given: Room temperature is 20°C. Exposed area of the person is 1.6 m2. Surface temperature of the…

Q: An average man has a body surface area of 1.8 m2  and a skin temperature of 330C. The convective…

A: Let A = Surface area of man body =1.8m2 V =1.2m/s h =Heat Transfer Coefficient =8.6XVX0.53 h…

Q: What is(roughness)? what is its effect on heat transfer?

A: Surface roughness, often known as roughness, is a characteristic of surface texture. The…

Q: Steam at 235°C is flowing inside a steel pipe(k = 61 W/m·K) whose inner and outer diameters are10 cm…

A: Given data: Inner dia of steel pipe, Di =10cm Outer dia of steel pipe, Do=12 cm Inside Heat transfer…