A group of 25 power transistors, dissipating 1.5 W each, are to be cooled by attaching them to a black-anodized square aluminum plate and mounting the plate on the wall of a room at 30°C. The emissivity of the transistor and the plate surfaces is 0.9. Assuming the heat transfer from the back side of the plate to be negligible and the temperature of the surrounding surfaces to be the same as the air temperature of the room, determine the size of the plate if the average surface temperature of the plate is not to exceed 50°C.

Q: Consider a person whose exposed surface area is 1.7 m², emissivity is 0.7, and surface temperature…

A: (a) Write the given data. A=1.7 m2ε=0.7Ts=32 °C=305 KTw=300 K

Q: To control the temperature and drying rate of bread, a humidified baking oven is maintained at 166°C…

A: given data;dry bulb temperature (t)=1660cwet bulb temperature (ts)=600cheat transfer coefficient…

Q: Consider a large plane wall of thickness L = 0.8 ft and thermal conductivity K=1.2 Btu/h-ft-*F. The…

A: GivenL=0.8 ftk=1.2 Btu/h ftoFε=0.80α=0.60T1=524 Rq˙solar=300 Btu/h ft2Tsurr=0Kσ=0.1714×10-8 Btu/h…

Q: determine the actual temperature of the gas

A: Given: T= 380K  Tth= 540 K h= 130 W/m2.C e1=0.7 w2=0.05 e3=0.02 To determine: Actual temperature of…

Q: A person stands in front of a fire at 650 C in a room where air is at 5°C. Assuming the body…

A: Given data T = 650° C  Temperature of air = 5°C Body temperature = 37°C Coefficient of conduction =…

Q: An industrial spherical oven has 2.8 m diameter. It is placed in a factory floor where the air…

A: Given:  D = 2.8 m,    Therefore    R = 1.4 m Ta = 25 oC = 25 +273 = 298 K Qpeak load = 905 kW Ts,…

Q: The door of an oven in the kitchen of a house is 0.5 m high and 0.7 m wide. When the oven is…

A: Given, Outside temperature of the door, To=32°C=32+273 K=305 K   Temperature of the room,…

Q: A person stands in front of a fire at 650°C in a room where air is at 5°C. Assuming the body…

A: Answer: The net heat flow from the body is 291.1 W.

Q: The roof of an automobile can be thought of as a flat plate with insulated bottom surface. Solar…

A:

Q: QUESTION 5: A vertical 2.0 m high and 2.0 m wide enclosure consists of two surfaces separated by a…

A: Radiation heat transfer is governed by Stephen Boltzmann law which state that the heat transfer…

Q: A man is working in a chamber enclosed with black walls. If the air around the worker is at 20oC,…

A: Given data: Tw=100°C=373 KTair=20°Ch=15 W/m2°Cε=0.8 Need to determine the temperature will the…

Q: When 1,800 l/min flows through a 200 mm diameter pipe, which later is reduced to 100 mm, what will…

A:

Q: Consider a person whose exposed surface area is 1.7 m², emissivity is 0.7, and surface temperature…

A: Given data: A=1.7 m2ε=0.7Tper=32°C=305 K Need to determine the heat loss by the person.

Q: A solar collector consists of a long duct through which air is blown; its cross section forms an…

A: Geometry:Length of duct (L) = 1 mSide length of equilateral triangle cross-section (a) = 1 mSurface…

Q: A radiant heating lamp has a surface temperature of 800 K with ε = 0.6 How large a surface area is…

A: Data given-  T = 800 K  ε = 0.6  Q = 350 W

Q: 02. An electronic box that consumes 180 W of power is cooled by a fan blowing air into the box…

A: We are supposed to answer only 3 parts, please post remaining parts as a separate question.

Q: A 50-cm x 50-cm circuit board that contains 121 square chips on one side is to be cooled by combined…

A:

Q: In the summer, parked automobile surfaces frequently average 104 °F to 50°C and surface emissivity…

A:

Q: Consider a person standing in a room. The inner surfaces of the walls, floors, and ceiling of the…

A:

Q: A thermocouple used to measure the temperature of hot air flowing in a duct whose walls are…

A: Given data: Tw=500 KTth=850 Kε=0.6h=60 W/m.°C Need to determine the actual temperature of air.

Q: A certain 1m body at 20 C is display on a top of a building during the night. the body sees nothing…

A: Given data , e= 0.9  Temperature to be maintained is  T= 23°C= 296 K  T1=110 K  t= 20°C

Q: A 2-m-diameter thin-walled stainless steel spherical tank is filled with chemicals undergoing a…

A: Given data as per question Diameter =2 m Surface temperature = 500 c Air temperature  = 200 c…

Q: IS are w = 500 K shows a temperature reac SSLUming -be onmisci f be

A:

Q: 2 inch OD during a visit to a plastic sheet factory 60 m long section of a horizontal steam pipe…

A:

Q: Consider a person standing in a room kept at 22°C at all times. It was observed that the interior…

A: According to the information we know have to Take an individual in a room always kept at 295°K. The…

Q: The solar radiation incident on the outside surface of an aluminum shading device is 1300 W/m2.…

A: Given: Solar radiation = 1300W/m2 Aluminum absorbs 10%  The convection heat transfer coefficient is…

Q: A flat-plate collector with one glass cover is placed in horizontal. The absorber plate temperature…

A:

Q: thermocouple shielded by a layer of aluminum foil and copper with an emissivity of 0.05 and 0.02 is…

A: Given: A thermocouple shielded by a layer of aluminum foil and copper with an emissivity of 0.05 and…

Q: Consider steady heat transfer between two large parallel plates at constant temperatures T1 = 300 K…

A:

Q: A 1.2 m wide and 5.1 m long solar collector is mounted to a roof.  Now the average surface…

A: Given width of solar collector w=1.2 m Length of solar collector l=5.1 m Average surface temperature…

Q: a certain body at 20 C is display on a top of a building during the night. the body sees nothing but…

A: Given data,  T1= 20°C = 293K  T=23°C = 296 K  To=110 K  ε= 0.92  Let the Stefan Boltzmann constant…

Conduction and Convection

When energy travels from one object to another it is said to have undergone heat transfer. Heat transfer is nothing but the transfer of thermal energy or internal energy from one thing to another, like e.g., when a vessel with water, kept on top of a burner, heats up because of the flame underneath it.