(a) Explanation Express the mass of refrigerant. m = ν v 1 (I) Here, volume is ν and initial specific volume is v 1 . Express the final quality. x 2 = v 2 − v f , 2 v g , 2 − v f , 2 (II) Here, final specific volume is v 2 and specific volume at saturated liquid and vapor is v f and v g respectively. Express the final specific internal energy. u 2 = u f , 2 + x 2 u f g , 2 (III) Here, specific internal energy at saturated liquid and evaporation is u f and u f g respectively. Express the final specific entropy s 2 = s f , 2 + x 2 s f g , 2 (IV) Here, specific entropy at saturated liquid and evaporation is s f and s f g respectively. Express the initial specific internal energy. u 1 = u f + x 1 u f g (V) Here, initial quality is x 1 . Express initial specific entropy. s 1 = s f + x 1 s f g (VI) Express initial specific volume. v 1 = v f + x 1 ( v g − v f ) (VII) Express the amount of heat transfer between the source and the refrigerant using the energy balance for the closed tank. E in − E out = Δ E system Q in = Δ U = m ( u 2 − u 1 ) (VIII) Here, the total energy entering the system is E in , the total energy leaving the system is E out , the change in the total energy of the system is Δ E system , amount of heat transfer is Q in , change in internal energy is Δ U , and initial and final specific internal energy is u 1 and u 2 respectively. Conclusion: Refer Table A-12E, “saturated refrigerant-134a-pressure table” and write the properties corresponding to initial pressure ( P 1 ) of 30 psia and initial quality ( x 1 ) of 0.55 . u f = 16.929 Btu / lbm u f g = 79.799 Btu / lbm s f = 0.03792 Btu / lbm ⋅ R s f g = 0.18595 Btu / lbm ⋅ R v f = 0.01209 ft 3 / lbm v g = 1.5506 ft 3 / lbm Since the volumes are constant, therefore v 1 = v 2 Here, final specific volume is v 2 . Refer Table A-12E, “saturated refrigerant-134a-pressure table” and write the properties corresponding to final pressure ( P 2 ) of 50 psia . u f , 2 = 24.824 Btu / lbm u f g , 2 = 75.228 Btu / lbm s f , 2 = 0.05412 Btu / lbm ⋅ R s f g , 2 = 0.16780 Btu / lbm ⋅ R v f , 2 = 0.01252 ft 3 / lbm v g , 2 = 0.79361 ft 3 / lbm Substitute 0.01209 ft 3 / lbm for v f , 0.55 for x 1 and 1.5506 ft 3 / lbm for v g in Equation (VII). v 1 = 0.01209 ft 3 / lbm + 0.55 ( 1.5506 − 0.01209 ) ft 3 / lbm = 0 (b) To determine The exergy destroyed during the process.

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ISBN: 9781266657610

Author: CENGEL

Publisher: MCG CUSTOM

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Chapter 8.8, Problem 36P

(a)

To determine

The amount of heat transfer between the source and the refrigerant.

(b)

To determine

The exergy destroyed during the process.

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Chapter 8.8, Problem 35P

Chapter 8.8, Problem 37P

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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. 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