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The roof of a minivan can be approximated as a flat plate, 2-m wide and 3.5-m...
The roof of a minivan can be approximated as a flat plate, 2-m wide and 3.5-...
The roof of a minivan can be approximated as a flat plate, 2-m wide and 3.5- m long. The sun beats down on the roof such that the net solar radiation absorbed is 350 W/m2. If the ambient air is 32 ºC, the car is moving at 100 km/hr, and the inside surface of the roof is heavily insulated, determine the steady-state temperature of the roof (in ºC). Ignore heat loss via radiation emitted from the roof to the surrounding.
5 The roof of a car in a parking lot absorbs a solar radiant flux of...
5 The roof of a car in a parking lot absorbs a solar radiant flux of 800 W/m2 and the underside is perfectly insulated. The convection coefficient between the roof and the ambient air is 12 W/m2.K. (a) Neglecting radiation exchange with the surroundings, calculate the temperature of the roof under steady state conditions if the ambient air temperature is 20°C. (b) For the same ambient air temperature, calculate the temperature of the roof if its surface emissivity is 0.8.
A household oven door of 0.6-m height and 0.7-m width reaches an average surface temperature of...
A household oven door of 0.6-m height and 0.7-m width reaches an average surface temperature of 32°C during operation. The temperature of ambient air is 22°C. Assuming the door has an emissivity of 0.8 and the surroundings are also at 22°C, determine the heat transfer by free convection and the heat transfer by radiation. 1) What is the volumetric thermal expansion coefficient of air at the film temperature outside the oven door, in 1/K? 2) What is the Rayleigh number...
The roof of a refrigerated truck compartment consists of a layer of foamed urethane insulation (t2...
The roof of a refrigerated truck compartment consists of a layer of foamed urethane insulation (t2 = 62 mm, ki = 0.026 W/m K) between aluminum alloy panels (t1 = 6 mm, kp = 180 W/m K). The length of the roof is L = 9 m. The net solar radiation into the roof is 131 W/m2. The temperature of the inner surface is Ts,i = -3 °C and the air temperature is T. = 30 °C. The convective heat...
P2 (50 pts.) Assume the roof of a room in a typical house is 12 cm...
P2 (50 pts.) Assume the roof of a room in a typical house is 12 cm thick concrete slab with a thermal conductivity k = 1.50 W/m•°C. The roof of the room is 4 m wide and 4 m long. Assume convection heat transfer coefficients on the inner and outer surfaces of the roof are hi=6 and ho=10 W/m2°C, respectively. At noon, when the sun is "hotter" the solar irradiation is estimated to be color = 750 W/m- and the...
Thermal Resistance Analysis: Consider a 1.2 m high and 1.4 m wide double-pane window consisting o...
Thermal Resistance Analysis: Consider a 1.2 m high and 1.4 m wide double-pane window consisting of two 4 mm thick layers ofglass (k-0.85 W m-K) separated by a 8-min stagnant air space. (k= 0.025 W m-K) Determine the steady rate of heat transfer through this double-pane window and the temperature of its inner and outer surfaces on a day when the inside room temperature is maintained at 20 °C and the outside ambient temperature is 32 °C. Assume the convection...
Q2 (a) A 12 mm diameter mild steel sphere (k = 42.5 W/m K) is exposed...
Q2 (a) A 12 mm diameter mild steel sphere (k = 42.5 W/m K) is exposed to cooling airflow at 27 "C resulting in the convective coefficient, h = 114 W/m' K. The relevant properties of mild steel are given as follows: Density p= 7850 kg/m . Specific heat c = 475 J/kg K and thermal diffusivity a = 0.043 m/hr Determine: (i) Time required to cool the sphere (lumped parameter system) from 540 °C to 95°C. [7 marks] (ii)...
Consider a 1.2-m-high and 2-m-wide double-pane window consisting of two 3-mm-thick layers of glass (k =...
Consider a 1.2-m-high and 2-m-wide double-pane window consisting of two 3-mm-thick layers of glass (k = 0.78 W/m K) separated by a 12-mm-wide stagnant air space (k = 0.026 W/m K). Determine the steady rate of heat transfer through this double-pane window. R . and all the surface temperatures (inner and outer of each pane) within the circuit (which you will draw and correctly label) for a day during which the room is maintained at 24°C while the temperature of...
summatize the following info and break them into differeng key points. write them in yojr own...
summatize the following info and break them into differeng key points. write them in yojr own words
apartus
6.1 Introduction—The design of a successful hot box appa- ratus is influenced by many factors. Before beginning the design of an apparatus meeting this standard, the designer shall review the discussion on the limitations and accuracy, Section 13, discussions of the energy flows in a hot box, Annex A2, the metering box wall loss flow, Annex A3, and flanking loss, Annex...
summarizr the followung info and write them in your own words and break them into different...
summarizr the followung info and write them in your own words and break them into different key points. 6.5 Metering Chamber: 6.5.1 The minimum size of the metering box is governed by the metering area required to obtain a representative test area for the specimen (see 7.2) and for maintenance of reasonable test accuracy. For example, for specimens incorporating air spaces or stud spaces, the metering area shall span an integral number of spaces (see 5.5). The depth of...
5 The roof of a car in a parking lot absorbs a solar radiant flux of 800 W/m2 and the underside is perfectly insulated. The convection coefficient between the roof and the ambient air is 12 W/m2.K. (a) Neglecting radiation exchange with the surroundings, calculate the temperature of the roof under steady state conditions if the ambient air temperature is 20°C. (b) For the same ambient air temperature, calculate the temperature of the roof if its surface emissivity is 0.8.
The roof of a refrigerated truck compartment consists of a layer of foamed urethane insulation (t2 = 62 mm, ki = 0.026 W/m K) between aluminum alloy panels (t1 = 6 mm, kp = 180 W/m K). The length of the roof is L = 9 m. The net solar radiation into the roof is 131 W/m2. The temperature of the inner surface is Ts,i = -3 °C and the air temperature is T. = 30 °C. The convective heat...
P2 (50 pts.) Assume the roof of a room in a typical house is 12 cm thick concrete slab with a thermal conductivity k = 1.50 W/m•°C. The roof of the room is 4 m wide and 4 m long. Assume convection heat transfer coefficients on the inner and outer surfaces of the roof are hi=6 and ho=10 W/m2°C, respectively. At noon, when the sun is "hotter" the solar irradiation is estimated to be color = 750 W/m- and the...
Thermal Resistance Analysis: Consider a 1.2 m high and 1.4 m wide double-pane window consisting of two 4 mm thick layers ofglass (k-0.85 W m-K) separated by a 8-min stagnant air space. (k= 0.025 W m-K) Determine the steady rate of heat transfer through this double-pane window and the temperature of its inner and outer surfaces on a day when the inside room temperature is maintained at 20 °C and the outside ambient temperature is 32 °C. Assume the convection...
Q2 (a) A 12 mm diameter mild steel sphere (k = 42.5 W/m K) is exposed to cooling airflow at 27 "C resulting in the convective coefficient, h = 114 W/m' K. The relevant properties of mild steel are given as follows: Density p= 7850 kg/m . Specific heat c = 475 J/kg K and thermal diffusivity a = 0.043 m/hr Determine: (i) Time required to cool the sphere (lumped parameter system) from 540 °C to 95°C. [7 marks] (ii)...
Consider a 1.2-m-high and 2-m-wide double-pane window consisting of two 3-mm-thick layers of glass (k = 0.78 W/m K) separated by a 12-mm-wide stagnant air space (k = 0.026 W/m K). Determine the steady rate of heat transfer through this double-pane window. R . and all the surface temperatures (inner and outer of each pane) within the circuit (which you will draw and correctly label) for a day during which the room is maintained at 24°C while the temperature of...
summatize the following info and break them into differeng key points. write them in yojr own words
apartus
6.1 Introduction—The design of a successful hot box appa- ratus is influenced by many factors. Before beginning the design of an apparatus meeting this standard, the designer shall review the discussion on the limitations and accuracy, Section 13, discussions of the energy flows in a hot box, Annex A2, the metering box wall loss flow, Annex A3, and flanking loss, Annex...
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