Fundamentals of Heat and Mass Transfer
7th Edition
ISBN: 9780470917855
Author: Bergman, Theodore L./
Publisher: John Wiley & Sons Inc
expand_more
expand_more
format_list_bulleted
Videos
Question
Chapter 9, Problem 9.64P
To determine
The daily cost of heat loss from an uninsulated pipe per unit length.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
A non-thermally insulated industrial water vapor pipe is 25 m long and 100 mm in diameter. This line crosses a building whose walls and ambient air are at 25oC. Pressurized steam holds the tube surface at 150oC and the convective coefficient is 10 W/(m.K). The surface emissivity is ε=0.8.
(a) the heat loss on this line;
(b) if the steam is generated in a boiler that operates at 90% efficiency and uses natural gas priced at $0.20/MJ, what is the annual cost of this heat loss?
Answer: (a) 18.41 W; (b) $129,000
A large bare duct having a diameter of 25cm runs horizontally
across a factory area having environmental conditions of 20.C and
1 atm. The length of the duct is 100 m. Inside the duct a low
pressure steam flow maintains the duct wall temperature constant
at 120.C. Calculate the total heat lost by convection from the duct
to the room
Air at atmospheric pressure and 25oC is heated in a tube with an ID of 25 mm. The tube wall is maintained at a temperature of 200oC. What length of tube is required to achieve an outlet air temperature of 120oC if the air flow is 10 Nm3/hr?
Chapter 9 Solutions
Fundamentals of Heat and Mass Transfer
Ch. 9 - The one-dimensional plane wall of Figure 3.1 is of...Ch. 9 - Using the values of density for water in Table...Ch. 9 - Consider an object of Characteristic length 0.01 m...Ch. 9 - To assess the efficacy of different liquids for...Ch. 9 - In many cases, we are concerned with free...Ch. 9 - The heat transfer rate due to free convection from...Ch. 9 - Consider a large vertical plate with a uniform...Ch. 9 - For laminar free convection flow on a vertical...Ch. 9 - Consider an array of vertical rectangular tins,...Ch. 9 - A number of thin plates are to be cooled by...
Ch. 9 - Prob. 9.11PCh. 9 - Prob. 9.13PCh. 9 - The plate described in Problem 9.14 has been used...Ch. 9 - Determine the average convection heat transfer...Ch. 9 - Consider a vertical plate of dimension 0.025m0.50m...Ch. 9 - During a winter day, the window of a patio door...Ch. 9 - Prob. 9.20PCh. 9 - A household oven door of 0.5-m height and 0.7-m...Ch. 9 - Consider a vertical, single-pane window of...Ch. 9 - Consider laminar flow about a vertical isothermal...Ch. 9 - Consider the conveyor system described in Problem...Ch. 9 - Prob. 9.25PCh. 9 - Consider an experiment to investigate the...Ch. 9 - The vertical rear window of an automobile is of...Ch. 9 - Prob. 9.28PCh. 9 - Prob. 9.29PCh. 9 - Prob. 9.30PCh. 9 - A refrigerator door has a height and width of...Ch. 9 - In the central receiver concept of a solar power...Ch. 9 - Prob. 9.34PCh. 9 - Airflow through a long, 0.2-m-square air...Ch. 9 - Prob. 9.36PCh. 9 - An electrical heater in the form of a horizontal...Ch. 9 - Consider a horizontal 6-mm-thick, 100-mm-long...Ch. 9 - Prob. 9.39PCh. 9 - Prob. 9.40PCh. 9 - Prob. 9.41PCh. 9 - Many laptop computers are equipped with thermal...Ch. 9 - Prob. 9.43PCh. 9 - At the end of its manufacturing process, a silicon...Ch. 9 - Integrated circuit (IC) boards are stacked within...Ch. 9 - Prob. 9.48PCh. 9 - Prob. 9.50PCh. 9 - Prob. 9.51PCh. 9 - Prob. 9.52PCh. 9 - Prob. 9.53PCh. 9 - Prob. 9.54PCh. 9 - Prob. 9.55PCh. 9 - Prob. 9.56PCh. 9 - Prob. 9.57PCh. 9 - A horizontal tube of 12.5-mm diameter with an...Ch. 9 - Prob. 9.60PCh. 9 - Prob. 9.61PCh. 9 - Prob. 9.63PCh. 9 - Prob. 9.64PCh. 9 - Common practice in chemical processing plants is...Ch. 9 - Consider the electrical heater of Problem 7.49. If...Ch. 9 - Prob. 9.67PCh. 9 - A billet of stainless steel, AISI 316, with a...Ch. 9 - Lone stainless steel rods of 50-mm diameter are...Ch. 9 - Hot air flows from a furnace through a...Ch. 9 - A biological fluid moves at a flow rate of...Ch. 9 - A sphere of 25-mm diameter contains an embedded...Ch. 9 - Prob. 9.79PCh. 9 - A vertical array of circuit boards is immersed in...Ch. 9 - Prob. 9.81PCh. 9 - The front door of a dishwasher of width 580 mm has...Ch. 9 - A natural convection air healer consists of an...Ch. 9 - A bank of drying ovens is mounted on a rack in a...Ch. 9 - Prob. 9.85PCh. 9 - Prob. 9.86PCh. 9 - Prob. 9.87PCh. 9 - To reduce heat losses, a horizontal rectangular...Ch. 9 - Prob. 9.89PCh. 9 - Prob. 9.90PCh. 9 - Prob. 9.91PCh. 9 - Prob. 9.92PCh. 9 - A 50-mm-thick air gap separates two horizontal...Ch. 9 - Prob. 9.94PCh. 9 - A vertical, double-pane window, which is 1 m on a...Ch. 9 - The top surface (0.5m0.5m) of an oven is 60°C for...Ch. 9 - Prob. 9.97PCh. 9 - Prob. 9.98PCh. 9 - Consider the cylindrical. 0.12-m-diamter radiation...Ch. 9 - Prob. 9.100PCh. 9 - A solar collector design consists of an inner tube...Ch. 9 - Prob. 9.104PCh. 9 - Prob. 9.105PCh. 9 - Liquid nitrogen is stored in a thin-walled...Ch. 9 - Prob. 9.108PCh. 9 - Prob. 9.109PCh. 9 - Prob. 9.110PCh. 9 - Prob. 9.111PCh. 9 - Prob. 9.114PCh. 9 - Prob. 9.115PCh. 9 - Prob. 9.116PCh. 9 - Prob. 9.117PCh. 9 - A water bath is used to maintain canisters...Ch. 9 - On a very Still morning, the surface temperature...Ch. 9 - Fuel cells similar to the PEM cell of Example 1.5...
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
- The evaporator section of a heat pump is installed in a large tank of water, which is used as a heat source during the winter. As energy is extracted from the water, it begins to freeze, creating an ice/water bath at 0°C, which may be used for air conditioning during the summer. Consider summer cooling conditions for which air is passed through an array of copper tubes, each of inside diameter D = 50 mm, submerged in the bath. (a) If air enters each tube at a mean temperature of Tm,i = 25°C and a flow rate of m·=0.01 kg/s, what tube length L is needed to provide an exit temperature of Tm,o = 14°C? With 10 tubes passing through a tank of total volume V = 14 m3, which initially contains 81% ice by volume, how long would it take to completely melt the ice? The density and latent heat of fusion of ice are 942 kg/m3 and hsf = 3.34 × 10^5 J/kg, respectively.arrow_forwardChips of width L _ 15 mm on a side are mounted to a substrate that is installed in an enclosurewhose walls and air are maintained at a temperature of Tsur=T∞=25oC. The chips have an emissivity ofε=0.60 and a maximum allowable temperature of Ts=85oC.(a) If heat is rejected from the chips by radiation and natural convection, what is the maximum operatingpower of each chip? The convection coefficient may be approximated as h=11.7 W/m2K.(b) If a fan is used to maintain airflow through the enclosure and heat transfer is by only forcedconvection, with h=250 W/m2K, what is the maximum operating power?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_forward
- Chips of width L _ 15 mm on a side are mounted to a substrate that is installed in an enclosure whose walls and air are maintained at a temperature of Tsur=T∞=25oC. The chips have an emissivity of ε=0.60 and a maximum allowable temperature of Ts=85oC. (a) If heat is rejected from the chips by radiation and natural convection, what is the maximum operating power of each chip? The convection coefficient may be approximated as h=11.7 W/m2K. (b) If a fan is used to maintain airflow through the enclosure and heat transfer is by only forced convection, with h=250 W/m2K, what is the maximum operating power?arrow_forwardA tube bank uses an aligned array with 10 mm diameter tubes and ST=SL=60 mm. The arrangement is 10 lines of tubes with 7 tubes in each. Cold water flows inside the tubes and their surface is kept at 30 °C, while the combustion gases flow cross-flow to the bank of tubes, the inlet temperature of the gases is 450 °C and their velocity is 15 m/s. Combustion gases can be approximated as air at 1 atm. Determine: A) The outlet temperature of the combustion gasesB) The heat transfer coefficientC) The amount of heat transferred through the bank of tubesarrow_forwardI need the answer as soon as possiblearrow_forward
- Water at 310 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. -Tube, D = 0.25 m L = 8 m, & = 1 Air T= 700 K Water m = 5 kg/s Imo m.i -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.arrow_forwardA storage tank consists of a cylindrical section that has a length and inner and inner diameter of L=2 m and Di=1 m, respectively, and two hemispherical end sections. The tank is constructed form 20 mm thick glass (pyrex) and is exposed to ambient air for which the temperature is 300 K. The tank is used to store heated oil, which maintains the inner surface at a temperature of 400 K. Determine the electrical power that must be supplied to a heater submerged in the oil if the prescribed conditions are to be maintained. Radiation effects may be neglected, and the pyrex may be assumed to have a thermal conductivity of 1.4 W/m.K.arrow_forward6. Air flows at 120 o C in a thin-walled tube (k = 18 W/m o C) with h = 65 w/m 2 - o C. The inside diameter of the tube is 2.5 cm tand the thickness is 0.4 mm. The tube is exposed to an environment with h = 6.5 W/m 2 - o C and temperature of 15 o C. Calculate the the heat loss for 1 m length. What thickness of insulation having k = 40 W/m- 0 C should be added to reduce heat loss by 90 %.arrow_forward
- Solve it ASAParrow_forwardCalculate the rate of heat loss per foot and the thermal resistance for a 15 cm schedule40 steel pipe covered with a 7.5 cm thick layer of 85% magnesia. Superheated steamat 150°C flows inside the pipe ( hc = 170 W/(m2 K)) and still air at 16°C is on theoutside ( hc = 30 W/(m2 K))arrow_forwardA simple cavity wall consists of two brick layers separated by an air gap of 50 mm. If theinside air temperature is 20oC and the ambient outside temperature is 5oC, calculate theheat flux through the wall. Bricks are 100 mm thick with thermal conductivity kbrick = 1.2W/m K, hin = 10 W/m2 K, hout = 20 W/m2 K. The internal air cavity can be considered still (noconvection) with kair = 0.015 W/m K.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