Thermodynamics: An Engineering Approach
9th Edition
ISBN: 9781259822674
Author: Yunus A. Cengel Dr., Michael A. Boles
Publisher: McGraw-Hill Education
expand_more
expand_more
format_list_bulleted
Concept explainers
Videos
Textbook Question
Chapter 6.11, Problem 15P
Consider a pan of water being heated (a) by placing it on an electric range and (b) by placing a heating element in the water. Which method is a more efficient way of heating water? Explain.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solution
Students have asked these similar questions
motor supplies 200 kW at 6 Hz to flange A of the shaft shown in Figure. Gear B transfers 125 W of power to operating machinery in the factory, and the remaining power in the shaft is mansferred by gear D. Shafts (1) and (2) are solid aluminum (G = 28 GPa) shafts that have the same diameter and an allowable shear stress of t= 40 MPa. Shaft (3) is a solid steel (G = 80 GPa) shaft with an allowable shear stress of t = 55 MPa. Determine:
a) the minimum permissible diameter for aluminum shafts (1) and (2)
b) the minimum permissible diameter for steel shaft (3).
c) the rotation angle of gear D with respect to flange A if the shafts have the minimum permissible diameters as determined in (a) and (b).
First monthly exam
Gas dynamics
Third stage
Q1/Water at 15° C flow through a 300 mm diameter riveted steel pipe, E-3 mm with a head loss of 6 m in
300 m length. Determine the flow rate in pipe. Use moody chart.
Q2/ Assume a car's exhaust system can be approximated as 14 ft long and 0.125 ft-diameter cast-iron pipe (
= 0.00085 ft) with the equivalent of (6) regular 90° flanged elbows (KL = 0.3) and a muffler. The
muffler acts as a resistor with a loss coefficient of KL= 8.5. Determine the pressure at the beginning of the
exhaust system (pl) if the flowrate is 0.10 cfs, and the exhaust has the same properties as air.(p = 1.74 ×
10-3 slug/ft³, u= 4.7 x 10-7 lb.s/ft²) Use moody chart
(1)
MIDAS
Kel=0.3
Q3/Liquid ammonia at -20°C is flowing through a 30 m long section of a 5 mm diameter copper tube(e =
1.5 × 10-6 m) at a rate of 0.15 kg/s. Determine the pressure drop and the head losses.
.μ= 2.36 × 10-4 kg/m.s)p = 665.1 kg/m³
2/Y
Y+1
2Cp
Q1/ Show that
Cda
Az x
P1
mactual
Cdf
Af
R/T₁
2pf(P1-P2-zxgxpf)
Q2/ A simple jet carburetor has to supply 5 Kg of air per minute. The air is at a pressure of 1.013 bar
and a temperature of 27 °C. Calculate the throat diameter of the choke for air flow velocity of 90 m/sec.
Take velocity coefficient to be 0.8. Assume isentropic flow and the flow to be compressible.
Quiz/ Determine the air-fuel ratio supplied at 5000 m altitude by a carburetor which is adjusted to give
an air-fuel ratio of 14:1 at sea level where air temperature is 27 °C and pressure is 1.013 bar. The
temperature of air decreases with altitude as given by the expression
The air pressure decreases with altitude as per relation h = 19200 log10 (1.013), where P is in bar. State
any assumptions made.
t = ts
P
0.0065h
Chapter 6 Solutions
Thermodynamics: An Engineering Approach
Ch. 6.11 - A mechanic claims to have developed a car engine...Ch. 6.11 - Describe an imaginary process that violates both...Ch. 6.11 - Describe an imaginary process that satisfies the...Ch. 6.11 - Describe an imaginary process that satisfies the...Ch. 6.11 - An experimentalist claims to have raised the...Ch. 6.11 - Consider the process of baking potatoes in a...Ch. 6.11 - Prob. 7PCh. 6.11 - What are the characteristics of all heat engines?Ch. 6.11 - What is the KelvinPlanck expression of the second...Ch. 6.11 - Is it possible for a heat engine to operate...
Ch. 6.11 - Does a heat engine that has a thermal efficiency...Ch. 6.11 - In the absence of any friction and other...Ch. 6.11 - Are the efficiencies of all the work-producing...Ch. 6.11 - Baseboard heaters are basically electric...Ch. 6.11 - Consider a pan of water being heated (a) by...Ch. 6.11 - A heat engine has a total heat input of 1.3 kJ and...Ch. 6.11 - A steam power plant receives heat from a furnace...Ch. 6.11 - A heat engine has a heat input of 3 104 Btu/h and...Ch. 6.11 - A 600-MW steam power plant, which is cooled by a...Ch. 6.11 - A heat engine with a thermal efficiency of 45...Ch. 6.11 - A heat engine that propels a ship produces 500...Ch. 6.11 - A steam power plant with a power output of 150 MW...Ch. 6.11 - An automobile engine consumes fuel at a rate of 22...Ch. 6.11 - Solar energy stored in large bodies of water,...Ch. 6.11 - A coal-burning steam power plant produces a net...Ch. 6.11 - An Ocean Thermal Energy Conversion (OTEC) power...Ch. 6.11 - Prob. 27PCh. 6.11 - Prob. 29PCh. 6.11 - What is the difference between a refrigerator and...Ch. 6.11 - Prob. 31PCh. 6.11 - Define the coefficient of performance of a...Ch. 6.11 - Define the coefficient of performance of a heat...Ch. 6.11 - Prob. 34PCh. 6.11 - A refrigerator has a COP of 1.5. That is, the...Ch. 6.11 - In a refrigerator, heat is transferred from a...Ch. 6.11 - A heat pump is a device that absorbs energy from...Ch. 6.11 - What is the Clausius expression of the second law...Ch. 6.11 - Show that the KelvinPlanck and the Clausius...Ch. 6.11 - The coefficient of performance of a residential...Ch. 6.11 - A food freezer is to produce a 5-kW cooling...Ch. 6.11 - An automotive air conditioner produces a 1-kW...Ch. 6.11 - A food refrigerator is to provide a 15,000-kJ/h...Ch. 6.11 - Prob. 44PCh. 6.11 - Determine the COP of a heat pump that supplies...Ch. 6.11 - Prob. 46PCh. 6.11 - A heat pump with a COP of 1.4 is to produce a...Ch. 6.11 - An air conditioner removes heat steadily from a...Ch. 6.11 - A household refrigerator that has a power input of...Ch. 6.11 - When a man returns to his well-sealed house on a...Ch. 6.11 - Water enters an ice machine at 55F and leaves as...Ch. 6.11 - A refrigerator is used to cool water from 23 to 5C...Ch. 6.11 - A household refrigerator runs one-fourth of the...Ch. 6.11 - Consider an office room that is being cooled...Ch. 6.11 - A house that was heated by electric resistance...Ch. 6.11 - Refrigerant-134a enters the condenser of a...Ch. 6.11 - Refrigerant-134a enters the evaporator coils...Ch. 6.11 - An inventor claims to have developed a resistance...Ch. 6.11 - Prob. 60PCh. 6.11 - Why are engineers interested in reversible...Ch. 6.11 - A cold canned drink is left in a warmer room where...Ch. 6.11 - A block slides down an inclined plane with...Ch. 6.11 - Prob. 64PCh. 6.11 - Prob. 65PCh. 6.11 - Show that processes that use work for mixing are...Ch. 6.11 - Why does a nonquasi-equilibrium compression...Ch. 6.11 - Prob. 68PCh. 6.11 - Prob. 69PCh. 6.11 - What are the four processes that make up the...Ch. 6.11 - Prob. 71PCh. 6.11 - Prob. 72PCh. 6.11 - Prob. 73PCh. 6.11 - Somebody claims to have developed a new reversible...Ch. 6.11 - Is there any way to increase the efficiency of a...Ch. 6.11 - Consider two actual power plants operating with...Ch. 6.11 - You are an engineer in an electric-generation...Ch. 6.11 - Prob. 78PCh. 6.11 - A thermodynamicist claims to have developed a heat...Ch. 6.11 - A heat engine is operating on a Carnot cycle and...Ch. 6.11 - A completely reversible heat engine operates with...Ch. 6.11 - An inventor claims to have developed a heat engine...Ch. 6.11 - A Carnot heat engine operates between a source at...Ch. 6.11 - A heat engine is operating on a Carnot cycle and...Ch. 6.11 - A heat engine operates between a source at 477C...Ch. 6.11 - An experimentalist claims that, based on his...Ch. 6.11 - In tropical climates, the water near the surface...Ch. 6.11 - Prob. 89PCh. 6.11 - Prob. 90PCh. 6.11 - Prob. 91PCh. 6.11 - Prob. 92PCh. 6.11 - How can we increase the COP of a Carnot...Ch. 6.11 - In an effort to conserve energy in a heat-engine...Ch. 6.11 - Prob. 95PCh. 6.11 - Prob. 96PCh. 6.11 - A thermodynamicist claims to have developed a heat...Ch. 6.11 - Determine the minimum work per unit of heat...Ch. 6.11 - Prob. 99PCh. 6.11 - An air-conditioning system operating on the...Ch. 6.11 - A heat pump operates on a Carnot heat pump cycle...Ch. 6.11 - An air-conditioning system is used to maintain a...Ch. 6.11 - A Carnot refrigerator absorbs heat from a space at...Ch. 6.11 - Prob. 104PCh. 6.11 - A Carnot refrigerator operates in a room in which...Ch. 6.11 - Prob. 106PCh. 6.11 - A commercial refrigerator with refrigerant-134a as...Ch. 6.11 - Prob. 108PCh. 6.11 - A heat pump is to be used for heating a house in...Ch. 6.11 - A completely reversible heat pump has a COP of 1.6...Ch. 6.11 - A Carnot heat pump is to be used to heat a house...Ch. 6.11 - A Carnot heat engine receives heat from a...Ch. 6.11 - Prob. 113PCh. 6.11 - Derive an expression for the COP of a completely...Ch. 6.11 - Calculate and plot the COP of a completely...Ch. 6.11 - Prob. 116PCh. 6.11 - Prob. 117PCh. 6.11 - Prob. 118PCh. 6.11 - Someone proposes that the entire...Ch. 6.11 - Prob. 120PCh. 6.11 - Prob. 121PCh. 6.11 - Prob. 122PCh. 6.11 - It is commonly recommended that hot foods be...Ch. 6.11 - It is often stated that the refrigerator door...Ch. 6.11 - Prob. 125RPCh. 6.11 - Prob. 126RPCh. 6.11 - Prob. 127RPCh. 6.11 - A Carnot heat pump is used to heat and maintain a...Ch. 6.11 - A refrigeration system uses a water-cooled...Ch. 6.11 - A refrigeration system is to cool bread loaves...Ch. 6.11 - A heat pump with a COP of 2.8 is used to heat an...Ch. 6.11 - Prob. 132RPCh. 6.11 - Consider a Carnot heat-engine cycle executed in a...Ch. 6.11 - Prob. 134RPCh. 6.11 - Consider a Carnot refrigeration cycle executed in...Ch. 6.11 - Prob. 137RPCh. 6.11 - Consider two Carnot heat engines operating in...Ch. 6.11 - A heat engine operates between two reservoirs at...Ch. 6.11 - An old gas turbine has an efficiency of 21 percent...Ch. 6.11 - Prob. 141RPCh. 6.11 - Prob. 142RPCh. 6.11 - Prob. 143RPCh. 6.11 - The drinking water needs of a production facility...Ch. 6.11 - Prob. 145RPCh. 6.11 - Prob. 147RPCh. 6.11 - Prob. 148RPCh. 6.11 - Prob. 149RPCh. 6.11 - Prob. 150RPCh. 6.11 - Prob. 151RPCh. 6.11 - A heat pump with refrigerant-134a as the working...Ch. 6.11 - Prob. 153RPCh. 6.11 - Prob. 155RPCh. 6.11 - Prob. 156RPCh. 6.11 - Prob. 157RPCh. 6.11 - Prove that a refrigerators COP cannot exceed that...Ch. 6.11 - Consider a Carnot refrigerator and a Carnot heat...Ch. 6.11 - A 2.4-m-high 200-m2 house is maintained at 22C by...Ch. 6.11 - A window air conditioner that consumes 1 kW of...Ch. 6.11 - The drinking water needs of an office are met by...Ch. 6.11 - The label on a washing machine indicates that the...Ch. 6.11 - A heat pump is absorbing heat from the cold...Ch. 6.11 - A heat engine cycle is executed with steam in the...Ch. 6.11 - A heat pump cycle is executed with R134a under the...Ch. 6.11 - A refrigeration cycle is executed with R-134a...Ch. 6.11 - A heat pump with a COP of 3.2 is used to heat a...Ch. 6.11 - A heat engine cycle is executed with steam in the...Ch. 6.11 - A heat engine receives heat from a source at 1000C...Ch. 6.11 - An air-conditioning system operating on the...Ch. 6.11 - A refrigerator is removing heat from a cold medium...Ch. 6.11 - Two Carnot heat engines are operating in series...Ch. 6.11 - A typical new household refrigerator consumes...
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
- 36 2) Use the method of MEMBERS to determine the true magnitude and direction of the forces in members1 and 2 of the frame shown below in Fig 3.2. 300lbs/ft member-1 member-2 30° Fig 3.2. https://brightspace.cuny.edu/d21/le/content/433117/viewContent/29873977/Viewarrow_forwardCan you solve this for me?arrow_forward5670 mm The apartment in the ground floor of three floors building in Fig. in Baghdad city. The details of walls, roof, windows and door are shown. The window is a double glazing and air space thickness is 1.3cm Poorly Fitted-with Storm Sash with wood strip and storm window of 0.6 cm glass thickness. The thickness of door is 2.5 cm. The door is Poor Installation. There are two peoples in each room. The height of room is 280 cm. assume the indoor design conditions are 25°C DBT and 50 RH, and moisture content of 8 gw/kga. The moisture content of outdoor is 10.5 gw/kga. Calculate heat gain for living room : الشقة في الطابق الأرضي من مبنى ثلاثة طوابق في مدينة بغداد يظهر في مخطط الشقة تفاصيل الجدران والسقف والنوافذ والباب. النافذة عبارة عن زجاج مزدوج وسمك الفراغ الهوائي 1.3 سم ضعيف الاحكام مع ساتر حماية مع إطار خشبي والنافذة بسماكة زجاج 0.6 سم سماكة الباب 2.5 سم. الباب هو تركيب ضعيف هناك شخصان في كل غرفة. ارتفاع الغرفة 280 سم. افترض أن ظروف التصميم الداخلي هي DBT25 و R50 ، ومحتوى الرطوبة 8…arrow_forward
- How do i solve this problem?arrow_forwardQ4/ A compressor is driven motor by mean of a flat belt of thickness 10 mm and a width of 250 mm. The motor pulley is 300 mm diameter and run at 900 rpm and the compressor pulley is 1500 mm diameter. The shaft center distance is 1.5 m. The angle of contact of the smaller pulley is 220° and on the larger pulley is 270°. The coefficient of friction between the belt and the small pulley is 0.3, and between the belt and the large pulley is 0.25. The maximum allowable belt stress is 2 MPa and the belt density is 970 kg/m³. (a) What is the power capacity of the drive and (b) If the small pulley replaced by V-grooved pulley of diameter 300 mm, grooved angle of 34° and the coefficient of friction between belt and grooved pulley is 0.35. What will be the power capacity in this case, assuming that the diameter of the large pulley remain the same of 1500 mm.arrow_forwardYou are tasked with designing a power drive system to transmit power between a motor and a conveyor belt in a manufacturing facility as illustrated in figure. The design must ensure efficient power transmission, reliability, and safety. Given the following specifications and constraints, design drive system for this application: Specifications: Motor Power: The electric motor provides 10 kW of power at 1,500 RPM. Output Speed: The output shaft should rotate at 150 rpm. Design Decisions: Transmission ratio: Determine the necessary drive ratio for the system. Shaft Diameter: Design the shafts for both the motor and the conveyor end. Material Selection: Choose appropriate materials for the gears, shafts. Bearings: Select suitable rolling element bearings. Constraints: Space Limitation: The available space for the gear drive system is limited to a 1-meter-long section. Attribute 4 of CEP Depth of knowledge required Fundamentals-based, first principles analytical approach…arrow_forward
- - | العنوان In non-continuous dieless drawing process for copper tube as shown in Fig. (1), take the following data: Do-20mm, to=3mm, D=12mm, ti/to=0.6 and v.-15mm/s. Calculate: (1) area reduction RA, (2) drawing velocity v. Knowing that: ti: final thickness V. Fig. (1) ofthrearrow_forwardA direct extrusion operation produces the cross section shown in Fig. (2) from an aluminum billet whose diameter 160 mm and length - 700 mm. Determine the length of the extruded section at the end of the operation if the die angle -14° 60 X Fig. (2) Note: all dimensions in mm.arrow_forwardFor hot rolling processes, show that the average strain rate can be given as: = (1+5)√RdIn(+1)arrow_forward
- : +0 usão العنوان on to A vertical true centrifugal casting process is used to produce bushings that are 250 mm long and 200 mm in outside diameter. If the rotational speed during solidification is 500 rev/min, determine the inside radii at the top and bottom of the bushing if R-2R. Take: -9.81 mis ۲/۱ ostrararrow_forward: +0 العنوان use only In conventional drawing of a stainless steel wire, the original diameter D.-3mm, the area reduction at each die stand r-40%, and the proposed final diameter D.-0.5mm, how many die stands are required to complete this process. онarrow_forwardIn non-continuous dieless drawing process for copper tube as shown in Fig. (1), take the following data: Do-20mm, to=3mm, D=12mm, ti/to=0.6 and vo-15mm/s. Calculate: (1) area reduction RA, (2) drawing velocity v. Knowing that: t₁: final thickness D₁ V. Fig. (1) Darrow_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
Refrigeration and Air Conditioning Technology (Mi...Mechanical EngineeringISBN:9781305578296Author:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill JohnsonPublisher:Cengage Learning
Principles of Heat Transfer (Activate Learning wi...
Mechanical Engineering
ISBN:9781305387102
Author:Kreith, Frank; Manglik, Raj M.
Publisher:Cengage Learning
Refrigeration and Air Conditioning Technology (Mi...
Mechanical Engineering
ISBN:9781305578296
Author:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill Johnson
Publisher:Cengage Learning
Work, Energy, and Power: Crash Course Physics #9; Author: CrashCourse;https://www.youtube.com/watch?v=w4QFJb9a8vo;License: Standard YouTube License, CC-BY
Different Forms Of Energy | Physics; Author: Manocha Academy;https://www.youtube.com/watch?v=XiNx7YBnM-s;License: Standard Youtube License