Air Cooled Condenser Design Spreadsheet [PDF]

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CALCULATION FOR ROUND TUBE AND PLATE FIN HEAT Given Condition Temp. Air Entering,C Temp. Air Leaving, C Air Flowrate, m3/s Temp. Air Mean, C Temp. Water Entering, C Temp. Water Leaving, C Water Flowrate, m3/s Temp. Water Mean, C



42 47 61.48 44.5 55 45 0.01 50



From Book at Temp. Air Mean, C Density, kg/m3 Cp, kJ/kg-C u, kg/m-s Pr



44.5 1.11 1.01 1.924E-05 0.71



at Temp. Water Mean, C Density, kg/m3 Cp, kJ/kg-C u, kg/m-s Pr k, W/m-c



50 987.83 4.18 5.535E-04 3.6 0.64



315



Solve for Q - heat to be removed from water



258.21 kW Input Data: 1. Tube, Copper OD5/8" 2. T Wall Thickness, m 3. Tube ID , m 4. Fin Copper ,k, W/m2-c 5. Fin thickness, m 6. FPI 7. Number of Rows 8. Number of Pass 9. Number of Circuits 10. Coil Length, m 11. Coil Height, m 12. Coil Thickness, m 13. Tube Pitch, m



0.01 0 0.01 386 0 14 3 1 528 4.39 2422 1.7780 70 0.08 0.03



14. 15. 16. 17. 18. 19. 20. 21. 22. 23.



Coil Face Velocity,m/s Coil Face Area,m2 Water Vel. In-Tube,m/s O-Tube Cross Sect A,m2 I-Tube Cross Sect A,m2 Tube Pitch, m Number of Tubes/row Total Number of Tubes J Factor for Air Pi (1.5"x1.5"xod5/8")



7.87 7.8129 1.19 0 0 0.03 56 168 0.01 2.06



Solve for Number of Tubes



56.03 say Solve for Reynold Number of Water



23210.41 Solve for hw Film Coef. of Water, W/m2-c



6180.67 Solve for Fin Surface Area, m2



0.13 Solve for TOTAL Fin Surface Area, m2



607.37 Solve for TOTAL Tube Surface Area, m2



29.45 Solve for TOTAL HEATING SURFACE AREA, m2



636.82 Solve for Coil Volume, m3



0.644 Solve for Fin Volume, m3



0.057 Solve for Tube Volume, m3



0.094



56



Solve for Net Volume, m3



0.494 Solve for Free Flow Area, m2



5.990 Solve for Gcf, kg/m2-s



8.825 Solve for Gc, kg/m2-s



11.510 Solve for Dha, m



0.00310 Solve for Reynold Number of Air



1856.49 check J from book Solve for ha Film Coef. of Air, W/m2-c



102.17 Solve for M



57.52 Solve for n



0.85 Solve for Fin Efficiency



0.85 Solve for Tube, Atsa/A



0.046 Solve for Uo Coef. , W/m2-c



66.800 Solve for Heat Rate for Air, kJ/s-c



68.86 Minimum Solve for Heat Rate for Water, kJ/s-c



25.82 Using NTU METHOD



0.01



Solve by NTU



0.62 Solve for C



2.667 Solve for Effectiveness, E



0.278 Solve for Coil Capacity, Q



249 KW Solve for Design Margin, %



-3.50 % Checking Solve for Water Temp. Leaving. C



45.35 Solve for Air Temp. Leaving. C



45.62 Suggested Air Flowrate, m3/s



61.47



LATE FIN HEAT EXCHANGER



whole number



from book



3308.663



0.75



0.64



0.95



0.15



0.01



0



1.030



-0.0350219049140



2.80021