A 1000 m³ cubic building (meaning it is a cube with sides of length 10.0 m) has concrete walls 20 cm thick. Concrete has a thermal conductivity of 1.25 W/(mK). An indoor temperature of 21 C is maintained. If it is -15 C outside determine the rate of heat loss from the building. Answer: ✓ Choose... W

A 1000 m³ cubic building (meaning it is a cube with sides of length 10.0 m) has concrete walls 20 cm thick. Concrete has a thermal conductivity of 1.25 W/(mK). An indoor temperature of 21 C is maintained. If it is -15 C outside determine the rate of heat loss from the building. Answer: ✓ Choose... W

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.

Chapter1: Basic Modes Of Heat Transfer

Section: Chapter Questions

Problem 1.3P: 1.3 A furnace wall is to be constructed of brick having standard dimensions of Two kinds of...

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A plane wall 15 cm thick has a thermal conductivity given by the relation k=2.0+0.0005T[W/mK] where T is in kelvin. If one surface of this wall is maintained at 150C and the other at 50C, determine the rate of heat transfer per square meter. Sketch the temperature distribution through the wall.
2.15 Suppose that a pipe carrying a hot fluid with an external temperature of and outer radius is to be insulated with an insulation material of thermal conductivity k and outer radius . Show that if the convection heat transfer coefficient on the outside of the insulation is and the environmental temperature is , the addition of insulation actually increases the rate of heat loss if , and the maximum heat loss occurs when . This radius, is often called the critical radius.
1.3 A furnace wall is to be constructed of brick having standard dimensions of Two kinds of material are available. One has a maximum usable temperature of 1040°C and a thermal conductivity of 1.7 W/(m K), and the other has a maximum temperature limit of 870°C and a thermal conductivity of 0.85 W/(m K). The bricks have the same cost and are laid in any manner, but we wish to design the most economical wall for a furnace with a temperature of 1040°C on the hot side and 200°C on the cold side. If the maximum amount of heat transfer permissible is 950 , determine the most economical arrangement using the available bricks.
Using Table 1.4 as a guide, prepare a similar table showing the orders of magnitude of the thermal resistances of a unit area for convection between a surface and various fluids.
To determine the thermal conductivity of a structural material, a large 15-cm-thick slab of the material is subjected to a uniform heat flux of 2500 W/m2 while thermocouples embedded in the wall at 2.5 cm. intervals are read over a period of time. After the system had reached equilibrium, an operator recorded the thermocouple readings shown below for two different environmental conditions: Distance from the Surface (cm) Temperature (C) Test 1 0 40 5 65 10 97 15 132 Test 2 0 95 5 130 10 168 15 208 From these data, determine an approximate expression for the thermal conductivity as a function of temperature between 40 and 208C.
HEAT TRANSFER (a) Determine the thermal conductivity of an insulating material given the following data: steel pipe with 0.1025 m inner diameter and 0.1150 m outer diameter, insulation thickness 3 cm, heat flow per meter is 150 W/m, steel thermal conductivity 55 W/m-°C, and overall temperature difference of 72.2°C. If the temperature of the steam inside the pipe is 128°C, (b) find the outside temperature of the insulating material.
A glass windowpane in a home is 0.62 cm thick and has dimensions of 1.4 m × 1.8 m. On a certain day, the indoor temperature is 24°C and the outdoor temperature is 0°C. (a) What is the rate at which energy is transferred by heat through the glass? W(b) How much energy is lost through the window in one day, assuming the temperatures inside and outside remain constant? J
The inner and outer surface temperature of a 5.1 mm thick glass window are 17.6 and 7.1 oC, respectively. What is the heat loss in W through a window that is 1 m by 3 m on a side? The thermal conductivity of glass is 1.4 W/mK. Please keep one decimal and take positive value for the final answer.
Find the amount of heat lost per hour through a square foot ofbuilding wall composed of 18-in. sandstone and 3/4-in. metal lath andplaster separated by a 1 1/4-in. air space, when the temperature of theroom is 70 °F, the outdoors is 10 °F, and the wind velocity is 15 mph.
A certain insulation has a thickness of 2 cm. What thermal conductivity in W/m • *C is necessary to effect a temperature drop of 500 *C for a heat flow of 400 W/m2?
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…