
EBK THERMODYNAMICS: AN ENGINEERING APPR
9th Edition
ISBN: 8220106796979
Author: CENGEL
Publisher: YUZU
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Chapter 6.11, Problem 126RP
To determine
The claim of a manufacturer of ice cream freezers regarding the COP of these freezers.
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Water at 20 o C enters the 4 cm-diameter, 14 m-long tube at a rate of 0.8 kg/s. The surfacetemperature of the pipe is maintained at 165 o Cby condensing geothermal stream at the shellside of the heat exchanger. Use water properCesat 85 o C for all calculaCons.(a) Show that the water flow is turbulent and thermally fully developed. (b) EsCmate the heat transfer coefficient for convecCve heat transfer from the pipe to the water. For a fully developed turbulent flow within the smooth pipe, the Nu number can becalculated from the following equaCon:(c) Calculate the exit temperature of the water. (d) Share your opinion on whether the use of water properties at 85°C is appropriate. Yes or No because:
Consider a hot automotive engine, which can beapproximated as a 0.5-m-high, 0.40-m-wide, and 0.8-m-long rectangular block. The bottom surface of the block isat a temperature of 100°C and has an emissivity of 0.95.The ambient air is at 20°C, and the road surface is at25°C. Determine the rate of heat transfer from the bottomsurface of the engine block by convection and radiationas the car travels at a velocity of 80 km/h. Assume theflow to be turbulent over the entire surface because of theconstant agitation of the engine block. a) Calculate convective heat transfer coefficient (h). b) Calculate the total heat transfer rate
8 mm-
Top view
-200 mm-180 mm-
D
B
B
12 mm
Side view
B
-8 mm
D
PROBLEM 1.56
In an alternative design for the structure of
Prob. 1.55, a pin of 10-mm-diameter is to be
used at A. Assuming that all other
specifications remain unchanged, determine
the allowable load P if an overall factor of
safety of 3.0 is desired.
PROBLEM 1.55 In the structure shown, an 8-
mm-diameter pin is used at A, and 12-mm-
diameter pins are used at B and D. Knowing
that the ultimate shearing stress is 100 MPa at
all connections and that the ultimate normal
stress is 250 MPa in each of the two links
joining B and D, determine the allowable load
P if an overall factor of safety of 3.0 is desired.
20 mm
P
8 mm-
12 mm-
Front view
Chapter 6 Solutions
EBK THERMODYNAMICS: AN ENGINEERING APPR
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...
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