Explanation Write the expression for the energy balance equation for a closed system where the steam acts as the system. E in − E out = Δ E system W b,in − Q out = Δ U W b,in − Q out = m ( u 2 − u 1 ) (I) Here, net energy transfer in to the control volume is E in , net energy transfer exit from the control volume is E out , change in internal, kinetic, potential energies of the system is Δ E system , boundary work in the system is W b,in , amount of heat transferred from the system is Q out , change in internal energy of the system is Δ U , initial internal energy of the steam is u 1 and final internal energy of the steam is u 2 . Write the formula to calculate boundary work during the process ( w b,in ) . w b,in = P ( v 1 − v 2 ) (II) Here, pressure of the steam is P , initial specific volume of the steam is v 1 and final specific volume of the steam is v 2 . Write the formula to calculate heat transfer during the process ( q out ) using the energy balance equation. q out = w b,in − ( u 2 − u 1 ) (III) Write the expression to calculate the exergy change between the initial and final states ( Δ ϕ ) . Δ ϕ = ( ϕ 1 − ϕ 2 ) = u 2 − u 1 + P 0 ( v 1 − v 2 ) − T 0 ( s 1 − s 2 ) − q out ( 1 − T 0 T R ) (IV) Here, initial and final exergies of the steam are ϕ 1 and ϕ 2 respectively, surrounding temperature is T 0 , surrounding pressure is P 0 , initial and final specific entropies of the steam are s 1 and s 2 respectively and temperature of the thermal energy reservoir is T R . Write the formula to second-law efficiency of the process ( η II ) . η II = w b,in Δ ϕ (V) Conclusion: Refer Table A-5, “Saturated water-Pressure table”, obtain the following properties of steam at the pressure of 75 kPa for initial state. v 1 = v g = 2 .2172 m 3 / kg u 1 = u g = 2496 .1 kJ / kg s 1 = s g = 7 .4558 kJ / kg ⋅ K Here, specific volume of saturated vapor is v g , internal energy of saturated vapor is u g and specific entropy of saturated vapor is s g . Refer Table A-5, “Saturated water-Pressure table”, obtain the following properties of steam at the pressure of 75 kPa for final state. v 2 = v f = 0 .001037 m 3 / kg u 2 = u f = 384 .36 kJ / kg s 2 = s f = 1 .2132 kJ / kg ⋅ K Here, specific volume of saturated liquid is v f , internal energy of saturated liquid is u f and specific entropy of saturated liquid is s f . Substitute 75 kPa for P , 2 .2172 m 3 / kg for v 1 and 0 .001037 m 3 / kg for v 2 in Equation (II). w b,in = ( 75 kPa ) ( 2 .2172 m 3 / kg − 0 .001037 m 3 / kg ) = ( 75 kPa ) ( 2 .2172 m 3 / kg − 0 .001037 m 3 / kg ) ( 1 kJ 1 kPa ⋅ m 3 ) = 166.2 kJ / kg Substitute 166.2 kJ / kg for w b,in , 384 .36 kJ / kg for u 2 and 2496 .1 kJ / kg for u 1 in Equation (III)

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Chapter 8.8, Problem 89RP

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Ch. 8.8 - What final state will maximize the work output of...Ch. 8.8 - Is the exergy of a system different in different...Ch. 8.8 - Under what conditions does the reversible work...Ch. 8.8 - How does useful work differ from actual work? For...Ch. 8.8 - How does reversible work differ from useful work?Ch. 8.8 - Is a process during which no entropy is generated...Ch. 8.8 - Consider an environment of zero absolute pressure...Ch. 8.8 - It is well known that the actual work between the...Ch. 8.8 - Consider two geothermal wells whose energy...Ch. 8.8 - Consider two systems that are at the same pressure...

Ch. 8.8 - Prob. 11P Ch. 8.8 - Does a power plant that has a higher thermal...Ch. 8.8 - Prob. 13P Ch. 8.8 - Saturated steam is generated in a boiler by...Ch. 8.8 - One method of meeting the extra electric power...Ch. 8.8 - A heat engine that receives heat from a furnace at...Ch. 8.8 - Consider a thermal energy reservoir at 1500 K that...Ch. 8.8 - A heat engine receives heat from a source at 1100...Ch. 8.8 - A heat engine that rejects waste heat to a sink at...Ch. 8.8 - A geothermal power plant uses geothermal liquid...Ch. 8.8 - A house that is losing heat at a rate of 35,000...Ch. 8.8 - A freezer is maintained at 20F by removing heat...Ch. 8.8 - Prob. 24P Ch. 8.8 - Prob. 25P Ch. 8.8 - Prob. 26P Ch. 8.8 - Can a system have a higher second-law efficiency...Ch. 8.8 - A mass of 8 kg of helium undergoes a process from...Ch. 8.8 - Which is a more valuable resource for work...Ch. 8.8 - Which has the capability to produce the most work...Ch. 8.8 - The radiator of a steam heating system has a...Ch. 8.8 - A well-insulated rigid tank contains 6 lbm of a...Ch. 8.8 - A pistoncylinder device contains 8 kg of...Ch. 8.8 - Prob. 35P Ch. 8.8 - Prob. 36P Ch. 8.8 - Prob. 37P Ch. 8.8 - A pistoncylinder device initially contains 2 L of...Ch. 8.8 - A 0.8-m3 insulated rigid tank contains 1.54 kg of...Ch. 8.8 - An insulated pistoncylinder device initially...Ch. 8.8 - Prob. 41P Ch. 8.8 - An insulated rigid tank is divided into two equal...Ch. 8.8 - A 50-kg iron block and a 20-kg copper block, both...Ch. 8.8 - Prob. 45P Ch. 8.8 - Prob. 46P Ch. 8.8 - Prob. 47P Ch. 8.8 - A pistoncylinder device initially contains 1.4 kg...Ch. 8.8 - Prob. 49P Ch. 8.8 - Prob. 50P Ch. 8.8 - Prob. 51P Ch. 8.8 - Air enters a nozzle steadily at 200 kPa and 65C...Ch. 8.8 - Prob. 54P Ch. 8.8 - Prob. 55P Ch. 8.8 - Argon gas enters an adiabatic compressor at 120...Ch. 8.8 - Prob. 57P Ch. 8.8 - Prob. 58P Ch. 8.8 - The adiabatic compressor of a refrigeration system...Ch. 8.8 - Refrigerant-134a at 140 kPa and 10C is compressed...Ch. 8.8 - Air enters a compressor at ambient conditions of...Ch. 8.8 - Combustion gases enter a gas turbine at 900C, 800...Ch. 8.8 - Steam enters a turbine at 9 MPa, 600C, and 60 m/s...Ch. 8.8 - Refrigerant-134a is condensed in a refrigeration...Ch. 8.8 - Prob. 66P Ch. 8.8 - Refrigerant-22 absorbs heat from a cooled space at...Ch. 8.8 - Prob. 68P Ch. 8.8 - Prob. 69P Ch. 8.8 - Air enters a compressor at ambient conditions of...Ch. 8.8 - Hot combustion gases enter the nozzle of a...Ch. 8.8 - Prob. 72P Ch. 8.8 - A 0.6-m3 rigid tank is filled with saturated...Ch. 8.8 - Prob. 74P Ch. 8.8 - Prob. 75P Ch. 8.8 - An insulated vertical pistoncylinder device...Ch. 8.8 - Liquid water at 200 kPa and 15C is heated in a...Ch. 8.8 - Prob. 78P Ch. 8.8 - Prob. 79P Ch. 8.8 - A well-insulated shell-and-tube heat exchanger is...Ch. 8.8 - Steam is to be condensed on the shell side of a...Ch. 8.8 - Prob. 82P Ch. 8.8 - Prob. 83P Ch. 8.8 - Prob. 84P Ch. 8.8 - Prob. 85RP Ch. 8.8 - Prob. 86RP Ch. 8.8 - An aluminum pan has a flat bottom whose diameter...Ch. 8.8 - Prob. 88RP Ch. 8.8 - Prob. 89RP Ch. 8.8 - A well-insulated, thin-walled, counterflow heat...Ch. 8.8 - Prob. 92RP Ch. 8.8 - Prob. 93RP Ch. 8.8 - Prob. 94RP Ch. 8.8 - Prob. 95RP Ch. 8.8 - Nitrogen gas enters a diffuser at 100 kPa and 110C...Ch. 8.8 - Prob. 97RP Ch. 8.8 - Steam enters an adiabatic nozzle at 3.5 MPa and...Ch. 8.8 - Prob. 99RP Ch. 8.8 - A pistoncylinder device initially contains 8 ft3...Ch. 8.8 - An adiabatic turbine operates with air entering at...Ch. 8.8 - Steam at 7 MPa and 400C enters a two-stage...Ch. 8.8 - Prob. 103RP Ch. 8.8 - Steam enters a two-stage adiabatic turbine at 8...Ch. 8.8 - Prob. 105RP Ch. 8.8 - Prob. 106RP Ch. 8.8 - Prob. 107RP Ch. 8.8 - Prob. 108RP Ch. 8.8 - Prob. 109RP Ch. 8.8 - Prob. 111RP Ch. 8.8 - A passive solar house that was losing heat to the...Ch. 8.8 - Prob. 113RP Ch. 8.8 - A 4-L pressure cooker has an operating pressure of...Ch. 8.8 - Repeat Prob. 8114 if heat were supplied to the...Ch. 8.8 - Prob. 116RP Ch. 8.8 - A rigid 50-L nitrogen cylinder is equipped with a...Ch. 8.8 - Prob. 118RP Ch. 8.8 - Prob. 119RP Ch. 8.8 - Prob. 120RP Ch. 8.8 - Reconsider Prob. 8-120. The air stored in the tank...Ch. 8.8 - Prob. 122RP Ch. 8.8 - Prob. 123RP Ch. 8.8 - Prob. 124RP Ch. 8.8 - Prob. 125RP Ch. 8.8 - Prob. 126RP Ch. 8.8 - Prob. 127RP Ch. 8.8 - Water enters a pump at 100 kPa and 30C at a rate...Ch. 8.8 - Prob. 129RP Ch. 8.8 - Prob. 130RP Ch. 8.8 - Obtain a relation for the second-law efficiency of...Ch. 8.8 - Writing the first- and second-law relations and...Ch. 8.8 - Prob. 133RP Ch. 8.8 - Keeping the limitations imposed by the second law...Ch. 8.8 - Prob. 135FEP Ch. 8.8 - Prob. 136FEP Ch. 8.8 - Prob. 137FEP Ch. 8.8 - Prob. 138FEP Ch. 8.8 - A furnace can supply heat steadily at 1300 K at a...Ch. 8.8 - A heat engine receives heat from a source at 1500...Ch. 8.8 - Air is throttled from 50C and 800 kPa to a...Ch. 8.8 - Prob. 142FEP Ch. 8.8 - A 12-kg solid whose specific heat is 2.8 kJ/kgC is...

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Solution Summary: The author describes the energy balance equation for a closed system where the steam acts as the system.

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