Introduction to Heat Transfer
6th Edition
ISBN: 9780470501962
Author: Frank P. Incropera, David P. DeWitt, Theodore L. Bergman, Adrienne S. Lavine
Publisher: Wiley, John & Sons, Incorporated
expand_more
expand_more
format_list_bulleted
Videos
Question
Chapter 1, Problem 1.28P
(a)
To determine
Rate of heat loss from steam line.
(b)
To determine
Annual cost of heat loss from line.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
A pipe 30 m long with an outer diameter of 75 mm is used to deliver steam at a rate of 2000 kg / hour. The vapor pressure is 198.53 kPa entering the pipe with a quality of 98%. The pipe needs to be insulated with a thermal conductivity of 0.2 W / (m K) so that the quality of the steam will only slightly decrease to 95%. The outer surface temperature of the insulation is assumed to be 25 ° C. Ignore resistance conductive of the pipe material and it is assumed that there is no pressure drop in the pipe.
a. Determine the enthalpy of incoming vapor = AnswerkJ / kg.
b. Determine the enthalpy of steam coming out = AnswerkJ / kg.
c. Determine the vapor heat change / loss along the flow = Answerwatt.
d. Specify the minimum required insulation thickness = Answercm.
A pipe 30 m long with an outer diameter of 75 mm is used to deliver steam at a rate of 1500 kg / hour. The vapor pressure is 198.53 kPa entering the pipe with a quality of 98%. The pipe needs to be insulated with a thermal conductivity of 0.2 W / (m K) so that the quality of the steam will only slightly decrease to 95%. The outer surface temperature of the insulation is assumed to be 25 ° C. Ignore resistance conductive of the pipe material and it is assumed that there is no pressure drop in the pipe.
a. Determine the enthalpy of incoming vapor = Answer
kJ / kg.
b. Determine the enthalpy of steam coming out = Answer
kJ / kg.
c. Determine the vapor heat change / loss along the flow = Answer
watt.
d. Specify the minimum required insulation thickness = Answer
cm.
An uninsulated 100-mm diameter steam pipe runs for 25-meters inside a room whose walls and air are at a temperature of 25C .The superheated steam inside the pipe maintains the temperature at the pipe surface at 150C. If the natural convection heat transfer coefficient of the air outside the pipe is 10 W/(m^2)(k)and the surface emissivity is 0.8, compute for the total thermal resistance at the outside surface of the pipe in K/W.
Chapter 1 Solutions
Introduction to Heat Transfer
Ch. 1 - The thermal conductivity of a sheet of rigid,...Ch. 1 - The heat flux that is applied to the left face of...Ch. 1 - A concrete wall, which has a surface area of 20m2...Ch. 1 - The concrete slab of a basement is 11 m long, 8 m...Ch. 1 - Consider Figure 1.3. The heat flux in the...Ch. 1 - Prob. 1.6PCh. 1 - The inner and outer surface temperatures of a...Ch. 1 - A thermodynamic analysis of a proposed Brayton...Ch. 1 - A glass window of width W=1m and height H=2m is 5...Ch. 1 - Prob. 1.10P
Ch. 1 - The heat flux that is applied to one face of a...Ch. 1 - Prob. 1.12PCh. 1 - Prob. 1.13PCh. 1 - Prob. 1.14PCh. 1 - The 5-mm-thick bottom of a 200-mm-diameter pan may...Ch. 1 - Prob. 1.16PCh. 1 - For a boiling process such as shown in Figure...Ch. 1 - You've experienced convection cooling if you've...Ch. 1 - Prob. 1.19PCh. 1 - A wall has inner and outer surface temperatures of...Ch. 1 - An electric resistance heater is embedded in a...Ch. 1 - Prob. 1.22PCh. 1 - A transmission case measures W=0.30m on a side and...Ch. 1 - Prob. 1.24PCh. 1 - A common procedure for measuring the velocity of...Ch. 1 - Prob. 1.26PCh. 1 - Prob. 1.27PCh. 1 - Prob. 1.28PCh. 1 - Prob. 1.29PCh. 1 - Prob. 1.30PCh. 1 - Prob. 1.31PCh. 1 - Prob. 1.32PCh. 1 - Prob. 1.33PCh. 1 - Prob. 1.34PCh. 1 - An electrical resistor is connected to a battery,...Ch. 1 - Pressurized water pin=10bar,Tin=110C enters the...Ch. 1 - Consider the tube and inlet conditions of Problem...Ch. 1 - An internally reversible refrigerator has a...Ch. 1 - A household refrigerator operates with cold- and...Ch. 1 - Chips of width L=15mm on a side are mounted to a...Ch. 1 - Consider the transmission case of Problem 1.23,...Ch. 1 - One method for growing thin silicon sheets for...Ch. 1 - Heat is transferred by radiation and convection...Ch. 1 - Radioactive wastes are packed in a long,...Ch. 1 - An aluminum plate 4 mm thick is mounted in a...Ch. 1 - A blood warmer is to be used during the...Ch. 1 - Consider a carton of milk that is refrigerated at...Ch. 1 - The energy consumption associated with a home...Ch. 1 - Liquid oxygen, which hems a boiling point of 90 K...Ch. 1 - The emissivity of galvanized steel sheet, a common...Ch. 1 - Three electric resistance heaters of length...Ch. 1 - A hair dryer may be idealized as a circular duct...Ch. 1 - In one stage of an annealing process, 304...Ch. 1 - Convection ovens operate on the principle of...Ch. 1 - Annealing, an important step in semiconductor...Ch. 1 - In the thermal processing of semiconductor...Ch. 1 - A furnace for processing semiconductor materials...Ch. 1 - Single fuel cells such as the one of Example 1.5...Ch. 1 - Prob. 1.59PCh. 1 - Prob. 1.60PCh. 1 - Prob. 1.61PCh. 1 - A small sphere of reference-grade iron with a...Ch. 1 - A 50mm45mm20mm cell phone charger has a surface...Ch. 1 - A spherical, stainless steel (AISI 302) canister...Ch. 1 - Prob. 1.65PCh. 1 - Prob. 1.66PCh. 1 - A photovoltaic panel of dimension 2m4m is...Ch. 1 - Following the hot vacuum forming of a paper-pulp...Ch. 1 - Prob. 1.69PCh. 1 - Prob. 1.70PCh. 1 - Prob. 1.71PCh. 1 - The roof of a car in a parking lot absorbs a solar...Ch. 1 - Prob. 1.73PCh. 1 - Prob. 1.74PCh. 1 - Consider Problem 1.1. If the exposed cold surface...Ch. 1 - Prob. 1.76PCh. 1 - Prob. 1.77PCh. 1 - A thin electrical heating element provides a...Ch. 1 - Prob. 1.79PCh. 1 - Prob. 1.80PCh. 1 - Prob. 1.81PCh. 1 - The curing process of Example 1.9 involves...Ch. 1 - The diameter and surface emissivity of an...Ch. 1 - Bus bars proposed for use in a power transmission...Ch. 1 - A solar flux of 700W/m2 is incident on a...Ch. 1 - In considering the following problems involving...
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, mechanical-engineering and related others by exploring similar questions and additional content below.Similar questions
- 7.43 Liquid sodium is to be heated from 500 K to 600 K by passing it at a flow rate of 5.0 kg/s through a 5-cmID tube whose surface is maintained at 620 K. What length of tube is required?arrow_forwardAn electrical transmission line of 1.2-cm diameter carries a current of 200 amps and has a resistance of 310-4 ohm per meter of length. If the air around this line is at v, determine the surface temperature on a windy day, assuming a wind blows across the line at 33 km/h.arrow_forwardDetermine the rate of heat transfer per meter length to a light oil flowing through a 2.5-cm-ID, 60-cm-long copper tube at a velocity of 0.03 m/s. The oil enters the tube at 16C, and the tube is heated by steam condensing on its outer surface at atmospheric pressure with a heat transfer coefficient of 11.3 kW/m K. The properties of the oil at various temperatures are listed in the following table: Temperature, T(C) 15 30 40 65 100 (kg/m3) 912 912 896 880 864 c(kJ/kgK) 1.80 1.84 1.925 2.0 2.135 k(W/mK) 0.133 0.133 0.131 0.129 0.128 (kg/ms) 0.089 0.0414 0.023 0.00786 0.0033 Pr 1204 573 338 122 55arrow_forward
- A thick-walled cylindrical tubing of hard rubber (k=0.151 W/m*K) having an inside radius of 5 mm and an outside radius of 20 mm is being used as a temporary cooling coil in a bath. Ice water is flowing rapidly inside, and the inside wall temperature is 275 K. The outside surface temperature is 300 K. A total of 20 W must be removed from the bath by the cooling coil. How many meter of tubing are needed?arrow_forwardWater at 340 K and a flow rate of 5 kg/s enters a black, thin-walled tube, which passes through a large furnace whose walls and air are at a temperature of 700 K. The diameter and length of the tube are 0.25 m and 8 m, respectively. Convection coefficients associated with water flow through the tube and airflow over the tube are 300 W/m²-K and 50 W/m².K, respectively. Water Tme= i m = 5 kg/s Tai K Tube, D = 0.25 m L = 8 m, ε = 1 Air T= 700 K -Furnace, Tur 700 K Write an expression for the linearized radiation coefficient corresponding to radiation exchange between the outer surface of the pipe and the furnace walls. Determine how to calculate this coefficient if the surface temperature of the tube is represented by the arithmetic mean of its inlet and outlet values. Use these expressions to determine the outlet temperature of the water, Tm,o, in K. Tmoarrow_forwardA steam is flowing through a 5.7 m long of steel tube that has inner and outer radii of r, = 0.015 and r, 0,024 m, and a thermal conductivity of 0.14 W/m.K. The steam and the outer surface of the tube is maintained at constant temperature of 150 °C and the air = 25 °C, h = 0.35 W/m2.k) is surrounding the tube. To prevent the outer surface of the steel from the environmental conditions, a material that has a thermal conductivity of 0.014 W/m.k is wrapped over the outer surface of the steel. What is the maximum heat transfer from the steam to the air (W)? NOTE: Enter your answer. Answer Air Th Steam Steel Tr 111 Toarrow_forward
- Problem: Convection related Water enters a tube at 27°C with a flow rate of 450 kg/h. The rate of heat transfer from the tube wall to the fluid is given as qs′(W/m)=ax, where the coefficient a is 20 W/m^2 and x(m) is the axial distance from the tube entrance. (a) Beginning with a properly defined differential control volume in the tube, derive an expression for the temperature distribution Tm(x) of the water. (b) What is the outlet temperature of the water for a heated section 30 m long? (c) Sketch the mean fluid temperature, Tm(x), and the tube wall temperature, Ts(x), as a function of distance along the tube for fully developed and developing flow conditions.arrow_forwardWater flows at 67 C inside a 2.5 cm inside diameter tube such that hi = 3500 W/m² .C . The tube has a wall thickness 0.72 mm with a thermal conductivity of 18 W/m.C. The outside of the tube loses heat by free convection with ho= 7.6 W/m².C. Calculate the overall heat transfer coefficient and heat loss per unit length to surrounding air at 15 C.arrow_forwardan unsisulated 100 mm diameter steam pipe runs for 25 meters inside a room whose walls and air are at a temperature of 25 C. the superheated steam inside the pipe maintains the temperature at the pipe surface at 150 C. if the natural convection heat transfer coefficient of the air outside the pipe is 10 w/m^2 k and the surface emissivity is 0.8, compute for the convection thermal resistance of the air film surrounding the pipe in k/Warrow_forward
- 1 - A square chip, with side w = 5 mm, operates under isothermal conditions.The chip is positioned on a substrate so that its side and bottom surfaces are thermally insulated, while its top surface is exposed to theflow of a refrigerant at T∞ = 15°C. From reliability considerations, the chip temperature cannot exceed T = 85°C. The refrigerant being air, with a convection heat transfer coefficientcorresponding h = 200 W/(m2K), what is the maximum allowable power for the chip? Since the coolant is a dielectric liquid for which h = 3000 W/(m²K), what is the maximum allowed power?arrow_forwardA Pressurized Water Reactor fuel rod is 12 ft long and 0.374 inches in diameter (outer) on a 0.496 inch square pitch. The fuel pellet diameter is 0.3225 inches. The fuel rod gap is constant with a width of 0.0065 inches. The system pressure is 2250 psia and can be assumed to be constant. The rod operates at linear heat rate of 12.1 kW/ft. At the elevation of interest, the coolant temperature is 575 °F with a convective heat transfer coefficient of 6200- For this elevation determine the temperature BTU hr ft²F margin to boiling according to Jens-Lottes. Also assume constant fluid properties given as: p=46.39 Ibm = ,c. 1.261- BTU Ibm-F BTU -,k=0.334- hr-ft-F Ibm ft-hr M=0.222- -, Tsat 652.7F =arrow_forwardA heater coil is completely immersed in an oil bath that is insulated on all sides except for the top where the oil is in direct contact with the surrounding air that is maintained at a constant temperature, Oair. At t=0s, the coil is switched on and provides in watts of electrical power to the oil which has a thermal mass of moil and an initial temperature of Oinit-oil. The temperature of the oil is denoted by oil and the thermal resistance between the oil and air is Roil-air- a) Draw a schematic of the system clearly labeling the (assumed) directions of the heat transfer rates and the temperature at every node. b) Derive the governing differential equation for the temperature of the oil, oil- c) Where does Oinit-oil appear in the system schematic and how does it affect the governing equations? d) Derive an expression for the steady-state temperature of the oil as a function of the various system parameters.arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
Principles of Heat Transfer (Activate Learning wi...Mechanical EngineeringISBN:9781305387102Author:Kreith, Frank; Manglik, Raj M.Publisher:Cengage Learning
Principles of Heat Transfer (Activate Learning wi...
Mechanical Engineering
ISBN:9781305387102
Author:Kreith, Frank; Manglik, Raj M.
Publisher:Cengage Learning
Heat Transfer – Conduction, Convection and Radiation; Author: NG Science;https://www.youtube.com/watch?v=Me60Ti0E_rY;License: Standard youtube license