A metal furnace with a 1.25 m x 0.75 m metal door is placed in a room and set to 400K. A 0.3 m x 0.3 m glass window is located in the furnace door. The thickness of the metal alloy and the glass window are 3 mm and 2 mm, respectively. The glass window has a thermal conductivity (k) of 0.7 W/m .K and the metal door has a thermal conductivity (k) of 3.5 W/m.K. The convective heat coefficient hi and ho on each site of the furnace door is estimated as 10W/m2.K. Assuming the room temperature is held constant at 297 K, calculate the total heat loss from the furnace door. P.S Could you write the solution clearly to better understanding? Step by step using formulas. Another page with detailed steps would be better. Thanks in advance.

A metal furnace with a 1.25 m x 0.75 m metal door is placed in a room and set to 400K. A 0.3 m x 0.3 m glass window is located in the furnace door. The thickness of the metal alloy and the glass window are 3 mm and 2 mm, respectively. The glass window has a thermal conductivity (k) of 0.7 W/m .K and the metal door has a thermal conductivity (k) of 3.5 W/m.K. The convective heat coefficient hi and ho on each site of the furnace door is estimated as 10W/m2.K. Assuming the room temperature is held constant at 297 K, calculate the total heat loss from the furnace door. P.S Could you write the solution clearly to better understanding? Step by step using formulas. Another page with detailed steps would be better. Thanks in advance.

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...

See similar textbooks

Similar questions

1.10 A heat flux meter at the outer (cold) wall of a concrete building indicates that the heat loss through a wall of 10-cm thickness is . If a thermocouple at the inner surface of the wall indicates a temperature of 22°C while another at the outer surface shows 6°C, calculate the thermal conductivity of the concrete and compare your result with the value in Appendix 2, Table 11.
2.30 An electrical heater capable of generating 10,000 W is to be designed. The heating element is to be a stainless steel wire having an electrical resistivity of ohm-centimeter. The operating temperature of the stainless steel is to be no more than 1260°C. The heat transfer coefficient at the outer surface is expected to be no less than in a medium whose maximum temperature is 93°C. A transformer capable of delivering current at 9 and 12 V is available. Determine a suitable size for the wire, the current required, and discuss what effect a reduction in the heat transfer coefficient would have. (Hint: Demonstrate first that the temperature drop between the center and the surface of the wire is independent of the wire diameter, and determine its value.)
2.50 Compare the rate of heat flow from the bottom to the top of the aluminum structure shown in the sketch below with the rate of heat flow through a solid slab. The top is at v, the bottom at . The holes are filled with insulation that does not conduct heat appreciably.
1.63 Liquid oxygen (LOX) for the space shuttle is stored at 90 K prior to launch in a spherical container 4 m in diameter. To reduce the loss of oxygen, the sphere is insulated with superinsulation developed at the U.S. National Institute of Standards and Technology's Cryogenic Division; the superinsulation has an effective thermal conductivity of 0.00012 W/m K. If the outside temperature is on the average and the LOX has a heat of vaporization of 213 J/g, calculate the thickness of insulation required to keep the LOX evaporation rate below 200 g/h.
A plane wall of thickness 2L has internal heat sources whose strength varies according to qG=qocos(ax) Where qo is the heat generated per unit volume at the center of the wall (x=0) and a is a constant. If both sides of the wall are maintained at a constant temperature of Tw, derive an expression for the total heat loss from the wall per unit surface area.
1.37 Mild steel nails were driven through a solid wood wall consisting of two layers, each 2.5-cm thick, for reinforcement. If the total cross-sectional area of the nails is 0.5% of the wall area, determine the unit thermal conductance of the composite wall and the percent of the total heat flow that passes through the nails when the temperature difference across the wall is 25°C. Neglect contact resistance between the wood layers.
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.
2. A glass window has an area of 5.5 ft² and a thickness of 5 mm. If one side is at a temperature of 45° F and the other is at 23 F, how much thermal energy (BTU/year) flows through the window in one year? The thermal conductivity of glass is 1.89x10-4 kcal/m-s-K.
A wall in a house contains a single window. The window consists of a single pane of glass whose area is 0.13 m2 and whose thickness is 8 mm. Treat the wall as a slab of the insulating material Styrofoam whose area and thickness are 19 m2 and 0.10 m, respectively. Heat is lost via conduction through the wall and the window. The temperature difference between the inside and outside is the same for the wall and the window. Of the total heat lost by the wall and the window, what is the percentage lost by the window?
a metal bar is made up of 3.0 cm of aluminum and 5.0 cm of steel. the free end of the aluminum bar is placed in contact with steam at 100 degree Celsius. at the other side, the free end of the steel bar maintained at 0 degree Celsius by placing it in contact with the ice. find the temperature at the point that connect the aluminum and the steal (junction)
In a glass plant in Cavite, a furnace has fire-brick walls made up of the following two materials in series : Non-corrosive brick as inner layer (material 1) Clay brick as outer layer (material 2) Thickness 4.5 inches 8 inches Thermal conductivity k1 k2 The temperature inside the furnace (inside wall surface of the non-corrosive brick) is found to be 1105 oF while the outside temperature (outside wall surface of clay brick) is 365 oF. This is not the desired temperature inside the furnace so engineers thought of lagging the furnace walls with another material to reduce heat loss. The additional lagging material consists of magnesia layer which is 2 inches thick and has a thermal conductivity of 0.04 Btu /h.ft.oF. During a test run on the furnace with the magnesia lagging material now, new temperature readings were recorded : Point of measurement Temperature reading Inside furnace (inside wall surface of non-corrosive brick 1355 oF Interface between…
A ball made of steel alloy with a diameter of 2 millimeters is first heated to 800 degrees and then suddenly immersed in a water bath to cool down to 100 degrees. The materials from which the ball is made have a thermal conductivity coefficient of 54.94 w / mk, a heat capacity of 7860 kg / m3, a heat capacity of 450 j / kg. Also, the heat transfer coefficient is 41.66 2 / m2. a-)Find the temperature of the ball immersed in water after 10 seconds. b-)Find the time required to cool the ball to 400 degrees.