The greatest amount of exergy destroyed among the processes of system.

Answer to Problem 117RP
The greatest amount of exergy destroyed among the processes of system is
Explanation of Solution
Sketch the schematic layout of the two-stage compression refrigeration system as in Figure (1).
Sketch the
Write the relation between the specific enthalpies at the inlet and exit of throttling.
Here, specific enthalpy of the refrigerant at the inlet of throttling is
Write the energy balance equation for the separator.
Here, mass flow rate of the refrigerant at the end of high pressure compressor is
Write the expression to calculate the quality of the refrigerant
Here, specific enthalpy of the saturated liquid is
Write the expression to calculate the specific entropy for saturated refrigerant
Here, specific entropy of the saturated liquid is
Write the expression to calculate the rate of cooling produced
Here, specific enthalpy at the inlet of low pressure compressor is
Write the expression to calculate the rate of heat rejected from the system
Here, specific enthalpy at the exit of high pressure compressor is
Write the general expression to calculate the exergy destruction
Here, mass flow rate is
Conclusion:
From the Table A-11 of “Saturated refrigerant R-134a: Temperature”, obtain the properties of refrigerant at high pressure compressor inlet temperature
From the Table A-13 of “Superheated refrigerant R-134a”, obtain the specific enthalpy of high pressure compression exit at pressure
From the Table A-12 of “Saturated refrigerant R-134a: Pressure”, obtain the properties of refrigerant at high pressure cycle throttle inlet pressure of
Substitute
From the Table A-12 of “Saturated refrigerant R-134a: Pressure”, obtain the properties of refrigerant at high pressure cycle throttle exit temperature of
Substitute
Substitute
From the Table A-12 of “Saturated refrigerant R-134a: Pressure”, obtain the properties of refrigerant at low pressure cycle throttle inlet temperature of
Here, pressure of refrigerant at the separator is
Substitute
From the Table A-11 of “Saturated refrigerant R-134a: Temperature”, obtain the properties of refrigerant at low pressure expansion valve exit temperature
Substitute
Substitute 0.2437 for
From the Table A-11 of “Saturated refrigerant R-134a: Temperature”, obtain the properties of refrigerant at low pressure compressor inlet temperature
From the Table A-13 of “Superheated refrigerant R-134a”, obtain the specific enthalpy of low pressure compression exit at pressure
Substitute
Substitute
Substitute
Rewrite the Equation (VII) for the process 2 to 3.
Here, the temperature of the high temperature reservoir is
Substitute
Rewrite the Equation (VII) for the process 3 to 4.
Substitute
Rewrite the Equation (VII) for the process 5 to 6.
Substitute
Rewrite the Equation (VII) for the process 6 to 7.
Substitute
Rewrite the Equation (VII) for the separator process.
Substitute
The exergy destruction for the isentropic processes is zero. Hence,
Thus, the greatest amount of exergy destroyed among the processes of system is
Want to see more full solutions like this?
Chapter 11 Solutions
THERMODYNAMICS(SI UNITS,INTL.ED)EBOOK>I
- What is the configuration of the control loop if steam must be shut down in case of a problem? (I found this question on the internet and was wondering what the answer is) A.Valve is fail open, PIC is direct-acting, TIC is reverse acting, and controller algorithm is feed-forwarding.B. Valve is fail open, PIC is reverse-acting, TIC is direct acting, and controller algorithm is cascade.C. Valve is fail closed, PIC is direct-acting, TIC is reverse acting, and controller algorithm is feed-forward.D. Valve is fail closed, PIC is reverse-acting, TIC is reverse acting, and controller algorithm is cascade.arrow_forwardWhat is the procedure to replace the input bellows?(I found this question on the internet and was wondering what the correct answer is out of interest) Remove tubing, old bellows and flapper assembly, install new bellows, connect tubing, install flapper assembly, then calibrate the positioner.Remove tubing, old bellows and cam, install new bellows, connect tubing, install cam, then calibrate the positioner.C. Remove tubing and old bellows, align the quadrant beam, install new bellows and connect tubing, then calibrate the positioner.D. Remove tubing and old bellows, install new bellows and connect tubing, align the quadrant beam, then calibrate the positioner.arrow_forwardGiven the following information: (I found this question on the internet and was wondering what the correct answer is) Firing rate demand = 20% Fuel air ratio = 2:1 Fuel flow = 20% Minimum air flow setting = 5% What is the set point for the air flow controller? 5%B. 10%C. 25%D. 40%arrow_forward
- . Where is a dew point analyzer installed to measure instrument air?(I found this question on the internet and am wondering what the correct answer is) A. AB. BC. CD. Darrow_forwardThe piston at the bottom of the stroke is 0% open. Which adjustment will change the zero setting to 5% open? ( I found this sample question on the internet and was wondering what the correct answer is out of interest) A.Slide component 2 towards the pivotB. Slide component 2 away from the pivot.C. Increase spring tension using adjustment 1.D. Decrease spring tension using adjustment 1.arrow_forward(read image) (Answer: vA = 4.57 ft/sec)arrow_forward
- Elements Of ElectromagneticsMechanical EngineeringISBN:9780190698614Author:Sadiku, Matthew N. O.Publisher:Oxford University PressMechanics of Materials (10th Edition)Mechanical EngineeringISBN:9780134319650Author:Russell C. HibbelerPublisher:PEARSONThermodynamics: An Engineering ApproachMechanical EngineeringISBN:9781259822674Author:Yunus A. Cengel Dr., Michael A. BolesPublisher:McGraw-Hill Education
- Control Systems EngineeringMechanical EngineeringISBN:9781118170519Author:Norman S. NisePublisher:WILEYMechanics of Materials (MindTap Course List)Mechanical EngineeringISBN:9781337093347Author:Barry J. Goodno, James M. GerePublisher:Cengage LearningEngineering Mechanics: StaticsMechanical EngineeringISBN:9781118807330Author:James L. Meriam, L. G. Kraige, J. N. BoltonPublisher:WILEY





