1. The Thermodynamic of Manufacturing Processes Timothy G. Gutowski

2. Overview 1.Review of Basics 2.Intro to Exergy (Available Energy) 3.Analysis of Materials Transformation Processes 4.Results for Manufacturing Processes

3. References Thermodynamics Revisited; de Swaan Arons et al (handout) Thermodynamics Analysis of Mfg Processes; Gutowski et al (on webpage) Gyftopoulos and Beretta, Dover 2005

4. 1 st Law U = internal energy of molecules and atoms E = U + K.E. + P.E. = U + ½mv² + mgz “isolated” systems ∆E=0, or ∆U=0 (v=const, z=const) “closed” system ∆U = Q in – W out “open system” can exchange energy and mass

5. The 1st Law

6. Heat Engine THTH TLTL Q in Q out

7. Carnot

8. “Available Energy” Work and Heat are no longer equivalent Exergy, “B” is the available energy w.r.t. a reference environment, T 0, and P 0 … B(work) = W; B (heat) = Q(1-T 0 /T)

9. 2 nd law efficiency

10. Properties or State Variables T = temperature P = pressure V = volume U = internal energy E = energy B = exergy H = enthalpy (H = U + PV) S = entropy intensive variables extensive and intensive variables

11. State Variables

12. Enthalpy H=U+PV Here the Work done is W = P(V 2 – V 1 ) The First Law can be written asQ = (U+PV) 2 – (U + PV) 1 The quantity in parenthesis is Enthalpy H = U + PV The First Law can be written as Q in =  H Constant Pressure Equilibrium Process

13. Energy, E and Exergy, B B 1 -B 2 = E 1 -E 2 reversible process B 1 -B 2 > E 1 -E 2 irreversible process E 1, B 1 E 2, B 2 Ref: Gyftopoulos and Beretta Properties for two different states of the system shown by the boxes. This change may come about due to spontaneous changes or due to heat or work interaction, or mass transfer.

14. Entropy They show C R = T R = T 0 Entropy is a Property Entropy is a measure of something lost Ref: Gyftopoulos and Beretta

15. Example, Heat Interaction E 2 = E 1 +Q B 2 = B 1 + Q(1-T 0 /T)  S = (1/T 0 )(Q – Q + Q(T 0 /T)) = Q/T  S = Q/T Q, T T0T0

16. Example, Work Interaction E 2 = E 1 +W B 2 = B 1 + W  S = (W - W) = 0 W

17. Open System with H, S Consider the Work to bring the system from the reference environment at standard conditions, T o, p o to the state at T, p p o, T o p, T W Q, T o H, S

18. From EQ 1 & 2, de Swaan Arons Steady State Work to bring system from P o, T o to P, T

19. Minimum Work = Exergy

20. Exergy System State Reference State Maximum work obtainable between System and Reference States; or minimum work needed to raise System from the reference state to the System State

21. Exergy System State Reference State Maximum work obtainable between System and Reference States.

22. Definition of Exergy “B” “Exergy is the amount of work obtainable when some matter is brought to a state of thermodynamic equilibrium with the common components of the natural surroundings by means of reversible processes, involving interaction only with the above mentioned components of nature” [Szargut et al 1988].

23. Manufacturing Systems as open thermodynamic systems

24. Balances for Mfg Process Mass Energy Entropy

25. Work Rate for Mfg Process in Steady State

26. Exergy and Work Branham et al IEEE ISEE 2008 Examples: plastic work, melting, vaporizing etc.

27. Mfg Process Use of Electricity 1.Machining 2.Grinding 3.Casting 4.Injection Molding 5.Abrasive Waterjet 6.EDM 7.Laser DMD 8.CVD 9.Sputtering 10.Thermal Oxidation

28. Energy Requirements at the Machine Tool Production Machining CenterAutomated Milling Machine From Toyota 1999, and Kordonowy 2002.

29. Electric Energy Intensity for Manufacturing Processes Power (kW) Process Rate (cm3/sec) physics auxiliary equipment & infrastructure Process Rate (cm3/sec) Specific Energy (MJ/cm3)

30. All-electric vs. hybrid The hydraulic machine would be even higher than the hybrid curve Source: [Thiriez]

31. All-electric vs. hybrid The hydraulic plot would be even higher than the hybrid curve Source: [Thiriez]

32. Injection Molding Machines Does not account for the electric grid. Source: [Thiriez ‘06]

33. Thermal Oxidation, SiO 2 Ref: Murphy et al es&t 2003

34. Power Requirements Ref: Murphy et al es&t 2003

36. In General, over many manufacturing processes,

37. Specific Energy Requirements J/cm 3 for Various Mfg Processes Gutowski et al IEEE, ISEE 2007

38. Specific Energy Requirements J/cm 3 for Various Mfg Processes Conventional Processes Advanced Processes Micro/Nano 8 orders of magnitude Gutowski et al IEEE, ISEE 2007

39. Gutowski et al IEEE, ISEE 2007

40. Gutowski et al IEEE, ISEE 2007

41. Keep in Mind This is intensity not total used This is at the device –loses at energy conversion not included –investment into materials not included –infrastructure not included Suggestive of efficiency

42. Why are these energy intensities so high? stable and declining energy prices demand for small devices vapor phase processes with slow deposition rates efficiency used to enhance performance never the less, the trajectory of individual processes is toward faster rates and lower energy intensities

43. All Electric Vs Hydraulic Injection Molding Machines Source: [Thiriez 2006]

44. Exergy Analysis including Chemical Composition B = B ph + B ch B ph (T=T o, P=P o ) =0 –this is the “restricted dead state*” when B = B ph = 0, and B ch (  o ) = 0 –this is the “dead state”

45. Exergy Accounting B in B out B lost

46. Chemical Reactions

47. Example: Burning Carbon C+O 2  CO 2 B C +B O2 -B CO 2 =  B 410.3 kJ + 3.97 kJ – 19.9 kJ = 394.4kJ mole mole mole The maximum work you can get out of one mole of carbon is 394.4 kJ = 32.9 MJ mole of carbon kg

48. Chemical Properties referenced to the “environment” Crust Oceans Atmosphere T 0 = 298.2 K, P 0 = 101.3 kPA

49. Exergy Reference System pure metal, element oxides, sulfides… crustal component earth’s crust (ground state) chemical reactions extraction

50. Example; making pure iron from the crust Fe (c = 1)376.4 kJ/mole reduction Fe 2 O 3 (c=1)16.5 kJ/mole extraction Fe 2 O 3 (c = 1.3 x 10 -3 )0 kJ/mole (ground)

51. Work Rate for Mfg Process Here all chemical exergy terms (b ch ) are at T o, P o Branham et al IEEE ISEE 2008

52. Efficiency Measures: Degree of Perfection

53. Batch Induction Melter Inputs and Outputs Ductile Iron – Batch Electric Induction Exergy Analysis

54. Batch Induction Melter Exergy Analysis* *including losses at Utility

55. Batch Electric Induction Melting of 1 kg of melt Total Exergy In (Bin) = 11,155,000 J Useful Exergy Out (Bout) = 8,250,000J ComponentExergy in (J) Metallics8,700,000 Electricity*2,455,000 Batch Electric Degree of Perfection Degree of Perfection *not including utility losses

56. Plasma Enhanced Chemical Vapor Deposition (CVD)

57. Input Deposition Gases SpeciesInput mass (g) Input moles or primary energy Exergy (J)%Total Inputs SiH40.95 0.029579mol40928.6 0.749 O20.49 0.015313mol60.79 Ar0.34 0.008511mol99.5 N2196.9 7.028779mol4849.9 Input Cleaning Gases CH469.41 4.326643mol3598253 63.0 NF331.06 0.437453mol266931.6 Input Energy Electricity 2220000J 2220000 36.2 Outputs Undoped Silicate Glass laye 0.0248 0.000414mol3.2667 Plasma enhanced CVD

58. Data from Sarah Boyd et. al. (2006) Chemical Vapor Deposition (CVD) of a 600nm Undoped Silicate Glass (USG) layer at 400°C Total Exergy In (Bin) = 6,130,000J Useful Exergy Out (Bout) = 3.3J ComponentExergy in (J) Input Gases45,900 Cleaning Gases3,865,000 Electricity*2,220,000 Degree of Perfection CVD Degree of Perfection *not including utility losses

59. Reasons for a Low Efficiencies Use of high exergy and ultra-pure materials, often with only a small fraction going into the product Low yields Low processing rates Energy and Materials were inexpensive