A composite wall is made up of 10 cm of common brick against 15cm of concrete with 1.5 cm of plaster on inside of wall. Assume still air in room at 25 °C. The outside air at 40 °C the wind velocity is 25 km/hr. Note: Use standard tables for values of thermal conductivities and film co-efficient. Find: a) The thermal resistance of wall b) The overall heat transfer cop-efficient. c) The steady state heat transfer rate per unit area of wall d) Heat transfer if the outside and inside film resistances are disgraded

A composite wall is made up of 10 cm of common brick against 15cm of concrete with 1.5 cm of plaster on inside of wall. Assume still air in room at 25 °C. The outside air at 40 °C the wind velocity is 25 km/hr. Note: Use standard tables for values of thermal conductivities and film co-efficient. Find: a) The thermal resistance of wall b) The overall heat transfer cop-efficient. c) The steady state heat transfer rate per unit area of wall d) Heat transfer if the outside and inside film resistances are disgraded

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter2: Steady Heat Conduction

Section: Chapter Questions

Problem 2.26P

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A composite wall is made up of 10 cm of common brick against 15cm of concrete with 1.5 cm of plaster on inside of wall. Assume still air in room at 25 °C. The outside air at 40 °C the wind velocity is 25 km/hr. Note: Use standard tables for values of thermal conductivities and film co-efficient. Find: a) The thermal resistance of wall b) The overall heat transfer cop-efficient. c) The steady state heat transfer rate per unit area of wall d) Heat transfer if the outside and inside film resistances are disgraded.
In a concentrated solar power plant, molten salt tank is used to store the thermal energy from the sun during the day. The tank wall thickness is 3cm containing molten salt at a temperature of 390 degree Celsius. There is atmospheric air outside the tank at a temperature of 30 degree Celsius. Suppose heat is lost as a result of heat transfer from the molten salt to the atmospheric air. What is the mode of heat transfer in this condition? conduction then convection convection then conduction convection then conduction then convection conduction then convection then conduction
1) "Two-by-four" wood studs have actual dimensions of 4. 13 x 9.21 cm and a thermal conductivity of 0.1 W/m. °C. A typical wall for a house is constructed as shown below. Calculate: a) heat transfer rate through the wall, b) temperature of inside wall, outside wall, and insulation material; and (c) temperature drop across common brick. Disregard any contact resistances at interfaces. Outside air convection, h = 15 W/m?. °C Common brick, k= 0.69 8 cm 1.9 cm, k = 0.96 Gypsum sheath 1.9 cm. k= 048 40.6 cm Insulation, k = 0.04 2 x 4 studs Inside air convection, h= 7.5 W/m²• C
The steady-state temperature distribution in a one-dimensional wall of thermal conductivity k=83 (W/m) °C) and thickness 300 mm is observed to be T(°C) = ax2+bx+c, where a = -2500 °C/m2 , b = 500 °C/m, c = 250 °C and x is in meters. a) What is the heat generation rate ?̇ (W/m3 ) in the wall ? b) Find the maximum and minimum temperatures in the wall. c) Find the amount of heat transferred to the right side of the wall (for 1 m2 surface area.)
V:01 Expert Q&A Done Question 1: In your own words, write down the differences between thermodynamic and heat transfer. (3 Marks) Question 2: Estimate the heat loss per square metre of surface through a brick wall 0.5 m thick when the inner surface is at 400 K and the outside surface is at 300 K. The thermal conductivity of the brick may be taken as 0.7 W/mK. (2 Marks) Question 3: A furnace is constructed with 0.20 m of firebrick, 0.10 m of insulating brick, and 0.20 m of building brick. The inside temperature is 1200 K and the outside temperature is 330 K. If the thermal conductivities are as shown in the figure below, estimate the heat loss per unit area. (5 Marks) 1200 K 330 K Insulating brick X-0.10m k= 0.21 Ordinary brick X=0.20 m Fire brick X= 0.20 m k= 1.4 k= 0.7 (W/mK)
QUESTION-) 236 °C steam flows in a pipe which features are given below. Inner and outer diameters of pipe are 300 mm and 320 mm. Coefficient of heat transmission is 40 W/mK. It's external ambient is air and it's temperature is 20 °C. Take the temperature of the pipe's external surface 180 °C. It is known that the internal temp convection coefficient is 600 W/m^2K and external heat transfer coefficient is 5.9109 W/m^2K The pipe's length is 500 meter. You need to add the radiation in the calculation. The rate of the radiation emissivity is 0.85. You can take the environmental surface temp directly. IMPORTANT NOTE: Hi. I sent this question to be solved 3 times. But I faced with different and wrong answers in all. What i want to ask is that doesn't all the resistances except conduction and convection resistances need to change after adding the insulation materials to the pipe? In the solution the people who solved this question took the external surface temp constant. Shouldn't the…
QUESTION-) 236 °C steam flows in a pipe which features are given below. Inner and outer diameters of pipe are 300 mm and 320 mm. Coefficient of heat transmission is 40 W/mK. It's external ambient is air and it's temperature is 20 °C. Take the temperature of the pipe's external surface 180 °C. It is known that the internal temp convection coefficient is 600 W/m^2K and external heat transfer coefficient is 5,9109 W/m^2K The pipe's length is 500 meter. You need to add the radiation in the calculation. The rate of the radiation emissivity is 0.85. You can take the environmental surface temp directly. Please calculate the heat loss of pipe.
QUESTION-) 236 °C steam flows in a pipe which features are given below. Inner and outer diameters of pipe are 300 mm and 320 mm. Coefficient of heat transmission is 40 W/mK. It's external ambient is air and it's temperature is 20 °C. Take the temperature of the pipe's external surface 180 °C. It is known that the internal temp convection coefficient is 600 W/m^2K and external heat transfer coefficient is 5,9109 W/m^2K The pipe's length is 500 meter. You need to add the radiation in the calculation. The rate of the radiation emissivity is 0.85. You can take the environmental surface temp directly. a-) Please draw this question on the resistance network. b-) Please calculate the heat loss of pipe. c-) By applying insulation to this pipe, it is desired to reduce the heat loss to 20% of the uninsulated loss (option a). Calculate the insulation thickness accordingly. Take glass wool as insulation material.(Conductivity of glass wool = 0.040 W/mK.) Given, The temperature of steam inside the…
a. A slab of thermal insulator is 100 cm² in cross section and 2 cm thick. Its thermal conductivity is 2.4 x 10 -+ cal/(s cm C"). If the temperature difference between opposite faces is 180 F', how much heat flows through the slab in one day?
8) Consider two liquids, A and B. with temperatures Te > TA. The two objects are put into thermal contact for a time period. Without just saying 'heat flows from hot to cold' how would you prove to someone that a quantity of heat flowed from B to Á. (think of James Joule's experiments) 9) If the temperature of the sun were to suddenly double, by what multiplicative factor would the thermal radiation change ? Show Work
Steam passes at 250 ° C through a steel pipe with an inner diameter of 60 mm and an outer diameter of 75 mm. Pipe The heat transfer coefficients inside and outside are 500 and 25 W / m2K, respectively. Ambient temperature 20 ° C and The heat conduction coefficient of the pipe is 56.5 W / mK. a)Find the heat loss from the 5 m length of the pipe. b)What thickness of material with heat transfer coefficient 0.035 W / mK to reduce heat loss by 95%? insulation should be made.
Q1) Find the heat transfer rate through a plane wall 20cm thick and 0.1m? heat transfer area. The temperatures across the wall are 100 °C and 10 °C respectively and the thermal conductivity is varies according to the equation (k = 60(1+0.03T)). %3D