Energy Business Modelling

Embed Size (px)

Citation preview

  • 8/12/2019 Energy Business Modelling

    1/29

    1

    2

    3

    4

    5

    6

    7

    8

    9

    10

    11

    12

    13

    14

    15

    16

    17

    18

    19

    20

    21

    22

    23

    24

    25

    26

    27

    28

    2930

    31

    32

    33

    34

    35

    36

    37

    38

    39

    40

    41

    A B C D E F G H I J

    Example 9.1 - An EOQ Model for Bedrock's Problem

    Input Cells are shaded 100

    Annual Demand 12,000

    Ordering Cost 50.00 Order Holding Ordering Annual

    Unit Cost 25.00 size cost cost cost

    Unit holding cost per year (two options) 100 375 6,000 6,375

    (i) in s per year 200 750 3,000 3,750

    (ii) as % of unit cost 30.0% 300 1,125 2,000 3,125

    Unit holding cost per year = 7.50 400 1,500 1,500 3,000

    500 1,875 1,200 3,075

    Output 600 2,250 1,000 3,250

    EOQ 400.00 700 2,625 857 3,482

    No. of Orders/Year 30.0 800 3,000 750 3,750

    Total cost 303,000 Plot cell range F5:I14

    0

    1,000

    2,000

    3,000

    4,000

    5,000

    6,000

    7,000

    100 200 300 400 500 600 700 800

    A

    nnualcost

    Order quantity

    EOQ graph

    Holding cost Ordering cost Annual cost

    Figure 8.4 Economic order quantity (EOQ) model.

    (Note that this model has been modified)

  • 8/12/2019 Energy Business Modelling

    2/29

    1

    2

    3

    4

    5

    6

    7

    8

    9

    10

    11

    12

    13

    14

    1516

    17

    18

    19

    20

    21

    22

    23

    24

    25

    26

    27

    2829

    30

    31

    A B C D E F G

    Example 9.2 - The PROQ Model and Solution to Gizmo's Problem.

    Input Annual Demand 2,100

    Setup Cost 450.00

    Unit Cost 30.00

    Annual production rate 2,500

    Unit holding cost per year (two options)

    (i) in s per year

    (ii) as % of unit cost 20.0%

    Annual unit holding cost = 6.00

    Output PROQ 1403.12

    Production run time,Ro(in weeks) 29.18

    Optimal cycle time, To(in weeks) 34.74

    Maximum inventory level 224.5Annual holding cost 673

    Annual setup cost 673

    Total cost 64,347

    Cell Formula Copied to

    E10 IF(E9="",E8,E5*E9)

    E11 IF(E10=0,"Holding cost cannot be zero!","")

    E12 SQRT(2*E3*E4/E10)*SQRT(E6/(E6 - E3))

    E13 52*E12/E6

    E14 52*E12/E3

    E15 E12*(E6 - E3)/E6

    E16 0.5*E10*E15E17 E3*E4/E12

    E18 E16 + E17 + E3*E5

    Figure 8.5 Production order quantity (PROQ) model.

  • 8/12/2019 Energy Business Modelling

    3/29

    1

    2

    3

    4

    5

    6

    7

    8

    9

    10

    11

    12

    13

    14

    1516

    17

    18

    19

    20

    21

    22

    23

    24

    25

    26

    27

    2829

    30

    31

    H I J K L M N O P Q

    .

    Figure 8.5 Production order quantity (PROQ) model.

  • 8/12/2019 Energy Business Modelling

    4/29

    1

    2

    3

    4

    5

    6

    7

    8

    9

    10

    11

    12

    13

    14

    15

    1617

    18

    19

    20

    21

    22

    23

    24

    25

    26

    27

    28

    29

    30

    31

    32

    A B C D E F G H I

    Example 9.3 - A Quantity Discount Model for the Wheelie Company

    InputAnnual Demand 1,500 User input cells

    Ordering Cost 80.00 are shaded

    Unit holding cost per year (two options)

    (i) in s per year

    (ii) as % of unit cost 30.0%

    DISCOUNT TABLE Unit Cost = 10.00 8.00 6.00

    Minimum discount quantity, Min i= 0 1000 2000

    Annual unit holding cost = 3.00 2.40 1.80

    Output Qi = 282.8 316.2 365.1

    Adjusted order quantities = 282.8 1000.0 2000.0

    Total costs = 15,849 13,320 10,860

    Minimum total cost is 10,860 2

    Optimal order quantity is 2000.0

    Cycle time is 69.3 weeks

    Cell Formula Copied to

    F11 IF($G6="",$G7*F9,$G6) G11:H11

    F12 IF(F11=0,"Holding cost cannot be zero!","")

    F13 SQRT(2*$G3*$G4/F11) G13:H13

    F14 IF(F13>F10,F13,F10) G14:H14

    F15 $G3*$G4/F14 + 0.5*F14*F11 + $G3*F9 G15:H15

    F17 MIN(F15:H15)H17 MATCH(F17,F15:H15,0) - 1

    F18 OFFSET(F18,-4,H17)

    F19 52*F18/G3

    Figure 8.6 Quantity discount model for the Wheelie Company.

  • 8/12/2019 Energy Business Modelling

    5/29

    1

    2

    3

    45

    6

    7

    8

    9

    10

    11

    12

    13

    14

    15

    16

    17

    18

    19

    20

    21

    22

    23

    24

    25

    26

    A B C D E F G H I

    Example 9.4 - A Delivery Charge Model for the Farmers' Co-operative

    InputDaily Demand (in tonnes) 3.0 User input cells

    Unit Cost 100.00 are shadedUnit holding cost per day (two options)

    (i) in s per day 1.50

    (ii) as % of unit cost

    DELI VERY TABLE Reorder Cost = 80.00 130.00 180.00

    Maximum delivery quantity, Maxi= 10 20 30

    Daily unit holding cost = 1.50 1.50 1.50

    Output Qi = 17.9 22.8 26.8

    Adjusted order quantities = 10.0 20.0 26.8

    Total costs = 332 335 340

    Minimum total cost is 332 0

    Optimal order quantity is 10.0

    Cycle time is 3.3 days

    Cell Formula Copied to

    F13 SQRT(2*$G3*F9/F11) G13:H13

    F14 IF(F13

  • 8/12/2019 Energy Business Modelling

    6/29

    1

    2

    3

    4

    5

    6

    7

    8

    9

    10

    11

    12

    13

    14

    15

    16

    17

    18

    19

    20

    21

    22

    23

    24

    25

    26

    27

    2829

    30

    31

    32

    33

    34

    35

    36

    37

    38

    39

    A B C D E F G H

    Example 9.5 - An Inventory Model with Shortages Allowed

    Input Annual Demand 12,000

    Setup/Ordering Cost 50.00 User input cells

    Unit Cost 25.00 are shaded

    Holding cost (two options)

    (i) in s per year

    (ii) as % of unit cost 30.0%

    Shortage cost per unit per year 4.00

    Unit holding cost per year = 7.50

    Output Optimal order size, Qo 678.2

    Maximum stock level 235.9

    Back-order size 442.3

    No. of orders/year 17.7Cycle time 2.9 weeks

    Annual Costs..

    Setup/ordering cost 884.65

    Holding cost 307.70

    Shortage cost 576.95

    Purchase cost 300,000

    Total cost 301,769

    Cell Formula Copied to

    E10 IF(E8="",E7,E8*E5)

    E11 IF(E10=0, "Enter a value in either cell E7 or E8!","")E13 SQRT(2*E3*E4*(E9 + E10)/(E9*E10))

    E14 E9*E13/(E9 + E10)

    E15 E13 - E14

    E16 E3/E13

    E17 52/E16

    E19 E3*E4/E13

    E20 0.5*E10*E14*E14/E13

    E21 E9*(E13 - E14)^2/(2*E13)

    E22 E3*E5

    E23 SUM(E19:E22)

    Figure 8.8 Deterministic model with planned storages.

  • 8/12/2019 Energy Business Modelling

    7/29

    1

    2

    3

    4

    5

    6

    7

    8

    9

    10

    11

    12

    13

    14

    15

    16

    17

    18

    19

    20

    21

    22

    23

    24

    25

    26

    27

    2829

    30

    31

    32

    33

    34

    35

    36

    37

    38

    39

    I J K L M N O P Q

    .

    Figure 8.8 Deterministic model with planned storages.

  • 8/12/2019 Energy Business Modelling

    8/29

    1

    2

    3

    4

    5

    6

    7

    8

    9

    10

    11

    12

    13

    14

    1516

    17

    18

    19

    20

    21

    22

    23

    24

    25

    26

    27

    28

    29

    30

    31

    32

    33

    34

    35

    36

    37

    38

    3940

    41

    42

    43

    A B C D E F G H I J

    Example 9.6 - An Inventory Model with Storage Space Constraints

    Setup cost 1,500.0 User input cellsHolding cost (as % of unit cost) 30.0% are shaded

    Product Demand Unit Space EOQ Average Variable

    cost (per unit) (Qo) space costs

    Widget 10,000 18.00 0.3 2357.0 353.6 12,728

    Gadget 8,000 15.00 0.2 2309.4 230.9 10,392

    P 3,000 10.00 0.15 1732.1 129.9 5,196

    Totals = 714.4 28,316

    Product Demand Unit Space EOQ Average Variable

    cost (per unit) (Qo) space costs

    Widget 7054 18.00 0.3 1979.6 296.9 12,922Gadget 5643 15.00 0.2 1939.6 194.0 10,551

    P 2116 10.00 0.15 1454.7 109.1 5,275

    Totals = 600.0 28,749

    Percentage increase in variable costs = 1.53%

    Scaling Factor = 0.705 (Initially, set Scaling Factor = 1)

    Solver Par ameters

    Set Tar get Cell :E23

    Equal to:Max

    By Changing Cell s:E23

    Subject to Constrai nts:H18 =0 = Answer must be positive

    Cell Formula Copied to

    G8 SQRT(2*C8*G$3/(G$4*D8)) G9:G10

    H8 0.5*E8*G8 H9:H10

    I8 C8*G$3/G8 + 0.5*G8*D8*G$4 I9:I10

    H11 SUM(H8:H10) I11

    Copy range B6:I11 into B13:I18

    C15 C8*E$23 C16:C17I15 C8*G$3/G15 + 0.5*G15*D15*G$4 I16:I17

    I20 (I18 - I11)/I11

    Figure 8.9 Multiple-product model with storage space constraint.

  • 8/12/2019 Energy Business Modelling

    9/29

    1

    2

    3

    4

    5

    6

    7

    8

    9

    10

    11

    12

    13

    14

    1516

    17

    18

    19

    20

    21

    22

    23

    24

    25

    26

    27

    28

    29

    30

    31

    32

    33

    34

    35

    36

    37

    38

    3940

    41

    42

    43

    K L M

    .

    Figure 8.9 Multiple-product model with storage space constraint.

  • 8/12/2019 Energy Business Modelling

    10/29

    1

    2

    3

    4

    5

    6

    7

    8

    9

    10

    11

    12

    13

    14

    15

    1617

    18

    19

    20

    21

    22

    23

    24

    25

    26

    27

    28

    29

    30

    31

    A B C D E F G H I J

    Example 9.7 - The Newsboy Problem: A Probabilistic Model with Discrete Demand

    InputUnit Cost, C = 3.00Selling Price, S = 5.00 User input cells are shaded

    Scrap value, V = 0.75

    Output

    Indiv. Cumul. profit, EPiDemand, Di Pi CUMi Sales Profit

    1 10 0.05 1 10 20

    2 20 0.1 0.95 19.5 38

    3 30 0.15 0.85 28 52

    4 40 0.2 0.7 35 59

    5 50 0.2 0.5 40 58

    6 60 0.15 0.3 43 487 70 0.1 0.15 44.5 32

    8 80 0.05 0.05 45 11 4

    Optimal demand, Qo= 40 Maximum prof it = 59

    Cell Formula Copied to

    E11 SUM(D11:D$18) E12:E18

    F11 SUMPRODUCT(C$11:C11,D$11:D11) + C11*E12 F12:F17

    F18 SUMPRODUCT(C$11:C18,D$11:D18)

    G11 E$4*F11 - E$3*C11 + E$5*(C11 - F11) G12:G18

    I18 MATCH(H20,G11:G18,0)

    D20 OFFSET(C10,I18,0)

    H20 MAX(G11:G18)

    Figure 8.10 The Newsboy problem - a probabilistic model with discrete demand.

  • 8/12/2019 Energy Business Modelling

    11/29

    1

    2

    34

    5

    6

    7

    8

    9

    10

    11

    12

    13

    14

    15

    1617

    18

    19

    20

    21

    22

    23

    24

    25

    26

    A B C D E F G H I

    Example 9.8 - A Probabilistic Model with Shortages

    Input Holding cost, H = 40.00 All user input cellsShortage cost, B = 500.00 are shaded

    B/(B + H) = 0.93

    Output

    Indiv. Sum

    Demand, Di Pi SUMi1 3 0.4 0.4

    2 4 0.25 0.65

    3 5 0.13 0.78

    4 6 0.11 0.89

    5 7 0.05 0.94 = Optimal amount

    6 8 0.04 0.987 9 0.01 0.99

    8 10 0.01 1

    Cel l Formula Copied to

    E5 E4/(E4 + E3)

    E11 SUM(D$11:D11) E12:E18

    F11 IF(E11>=H$5)," = Optimal amount","")

    F12 IF(AND(E11=H$5)," = Optimal amount","") F13:F18

    Figure 8.11 Probabilistic model with shortages.

  • 8/12/2019 Energy Business Modelling

    12/29

    1

    2

    3

    4

    5

    6

    7

    8

    9

    10

    11

    12

    13

    14

    15

    16

    17

    1819

    20

    21

    22

    23

    24

    25

    26

    27

    28

    29

    30

    31

    A B C D E F G H I J K

    Example 9.9 - A Service-Level Model with Variable Demand/ Fixed Lead-Time

    I nput - must be in consistent time units

    Time (day, week, month, year) week Demandi s normally-distri buted

    Ordering/Setup Cost 100.00 Mean = 500

    Unit Cost 10.00 Standard deviation = 60Holding cost (two options) Service Level %, SL= 95%

    (i) in s per year Lead Time, Lt= 5 week

    (ii) as % of unit cost 30.0%

    Unit holding cost per week 0.058 52

    Output

    Reorder level/point, R 2721.0 Holding cost of safety stock 13

    Order quantity, Q 1316.6 Holding cost of normal stock 38

    Safety stock 221.0 Ordering/setup costs 38

    Total costs per week 89

    Cell Formula Copied to

    D8 E4 D10, K8, H16

    E10 IF(E9="",E8/G10,E9*E6/G10)

    G10 IF(E4="day",365,IF(E4="week",52,IF(E4="month",12,1)))

    E11 IF(E10=0,"Enter a value in either cell E8 or E9!","")

    D13 J5*J8 + D15

    D14 SQRT(2*J5*E5/E10)

    D15 ROUNDUP(NORMSINV(J7)*J6*SQRT(J8),0)

    J13 D15*E10

    J14 D14*E10/2

    J15 IF(D14=0,"",E5*J5/D14)

    J16 SUM(J13:J15)

    Figure 8.12 Service-level model with variable demand/fixed lead-time.

  • 8/12/2019 Energy Business Modelling

    13/29

    1

    2

    3

    45

    6

    7

    8

    9

    10

    11

    12

    13

    14

    15

    16

    17

    18

    19

    20

    21

    22

    23

    24

    25

    26

    27

    A B C D E F G H I J K

    Example 9.10 - A Service-Level Model with Fixed Demand/ Variable Lead-Time

    I nput - must be in consistent time units

    Time (day, week, month, year) week Lead-timeis normally-distributedDemand 500 Mean = 5

    Ordering/Setup Cost 100.00 Standard deviation = 1

    Unit Cost 10.00 Service Level %, SL= 95%

    Holding cost (two options)

    (i) in s per year User input cells are shaded

    (ii) as % of unit cost 30.0%

    Unit holding cost per week 0.058 52

    Output

    Lead time 6.6 week Holding cost of normal stock 38

    Reorder level/point, R 3322.4 Ordering/setup costs 38

    Order quantity, Q 1316.6 Total costs per week 76

    Cell Formula Copied to

    D14 J5 + NORMSINV(J7)*J6

    E14 E4

    D15 E5*D14

    D16 SQRT(2*E5*E6/E11)

    J14 D16*E11/2

    J15 E6*E5/D16

    J16 SUM(J14:J15)

    Figure 8.13 Service-level model with variable demand/variable lead-time.

  • 8/12/2019 Energy Business Modelling

    14/29

    1

    2

    3

    4

    56

    7

    8

    9

    10

    11

    12

    13

    14

    15

    16

    17

    18

    19

    20

    21

    22

    23

    A B C D E F G H I J K

    Example 9. 11 - A Periodic Review (i.e. Fixed-Period) Model

    I nput - must be in consistent time units Demandi s normally-distributed

    Time (day, week, month, year) day Mean = 40

    Ordering/Setup Cost 50.00 Standard deviation = 15Unit Cost 10.00 Service Level %, SL= 95%

    Holding cost (two options) Lead Time, Lt= 8 day

    (i) in s per year 20.00 Review Period = 16 day

    (ii) as % of unit cost Stock On-hand = 60

    Unit holding cost per day 0.055 365

    Output

    Reorder level/point, R 1081.0 Holding cost of safety stock 6.63

    Order quantity, Q 1021.0 Holding cost of normal stock 27.97

    Safety stock 121.0 Ordering/setup costs 1.96

    Total costs per day 36.56

    Cel l Formula Copied to

    D13 J4*(J7 + J8) + D15

    D14 D13 - J9

    D15 ROUNDUP(NORMSINV(J6)*J5*SQRT(J7+J8),0)

    Figure 8.14 Periodic review (fixed-period) model.

  • 8/12/2019 Energy Business Modelling

    15/29

    1

    2

    34

    5

    6

    7

    8

    9

    10

    11

    12

    13

    14

    15

    16

    17

    18

    19

    20

    21

    22

    23

    24

    25

    26

    27

    28

    29

    A B C D E F G H I J

    Example 9.12 - A Multi-Period Model with Several Constraints

    Input All user input cells are shadedAnnual Demand 3,600

    Ordering Cost 5.00 Output

    Unit Cost 2.00 EOQ 300.00

    Unit holding cost per year (two options) Cycle time

    (i) in s per year (in months) 1.0

    (ii) as % of unit cost 20.0% Total cost 7,320

    Unit holding cost per year 0.40

    Monthly Order Ending Cost per

    Month Demand Quantity Inventory Period

    1 240 270 30 546

    2 270 330 90 668

    3 450 360 0 725

    4 210 270 60 547

    5 240 270 90 548

    6 300 270 60 547

    7 330 330 60 667

    8 420 360 0 725

    9 240 270 30 546

    10 330 300 0 605

    11 300 300 0 605

    12 270 270 0 545

    Annual demand = 3,600 7,274 = Annual cost

    Objective: M inimize surplus stock = 420

    Note: Switch on the "Assume Linear Model" parameter in the Solver Options dialog box

    Figure 8.15 Multi-period model with several constraints.

  • 8/12/2019 Energy Business Modelling

    16/29

  • 8/12/2019 Energy Business Modelling

    17/29

    1

    2

    34

    5

    6

    7

    8

    9

    10

    11

    12

    13

    14

    15

    16

    17

    18

    19

    20

    21

    22

    23

    24

    25

    26

    27

    28

    29

    K

    Figure 8.15 Multi-period model with several constraints.

  • 8/12/2019 Energy Business Modelling

    18/29

    30

    31

    3233

    34

    35

    36

    37

    38

    39

    40

    41

    42

    43

    44

    45

    46

    47

    48

    49

    50

    K

    Figure 8.15 Multi-period model with several constraints.

  • 8/12/2019 Energy Business Modelling

    19/29

    1

    2

    3

    4

    5

    6

    7

    8

    9

    10

    11

    12

    13

    14

    15

    1617

    18

    19

    20

    21

    22

    23

    24

    25

    26

    27

    28

    2930

    31

    32

    33

    34

    35

    A B C D E F G H I J K L M

    Example 9.13 - A Simulation Model for Inventory Control

    Demand table Lead-time table Dem- No. of

    Lower Upper and Pi Lower Upper days Pi0 0.03 0 0.03 0 0.20 1 0.20 User input

    0.03 0.08 1 0.05 0.20 0.70 2 0.50 cells are

    0.08 0.21 2 0.13 0.70 1.00 3 0.30 shaded

    0.21 0.46 3 0.25 1.00

    0.46 0.68 4 0.22

    0.68 0.88 5 0.20 Reorder level = 15

    0.88 1.00 6 0.12 Order quantity = 30

    1.00

    Output table

    Units Begin. RAND Dem- Ending New Lost Lead Recpt.Day Recvd. Invntry. No. and Invntry. Level sales Order? time Day

    1 30 0.31 3 27 27 0 No

    2 0 27 0.48 4 23 23 0 No

    3 0 23 0.52 4 19 19 0 No

    4 0 19 0.52 4 15 15 0 Yes 1 6

    5 0 15 1.00 6 9 39 0 No

    6 30 39 0.05 1 38 38 0 No

    7 0 38 0.20 2 36 36 0 No

    8 0 36 0.97 6 30 30 0 No

    9 0 30 0.74 5 25 25 0 No

    10 0 25 0.49 4 21 21 0 No

    11 0 21 0.22 3 18 18 0 No

    12 0 18 0.77 5 13 13 0 Yes 3 1613 0 13 0.95 6 7 37 0 No

    14 0 7 0.15 2 5 35 0 No

    55 0

    Service Level = 100.0%

  • 8/12/2019 Energy Business Modelling

    20/29

    1

    2

    3

    4

    5

    6

    7

    8

    9

    10

    11

    12

    13

    14

    15

    16

    1718

    19

    20

    21

    22

    23

    24

    25

    26

    27

    28

    2930

    31

    32

    33

    34

    35

    36

    37

    38

    39

    40

    41

    42

    43

    44

    45

    46

    A B C D E F G H I J K L

    Case Study 9.1 - A Material Requirements Planning (MRP) Model

    The BOM Table

    Part Number: Descr iption BOM I d. No. of Lead On Planned

    Level Code Units Time Hand Order User input

    Table 0 1 1 1 50 Rel. Row cells are

    Top Assembly 1 1001 1 2 50 25 shaded

    Table Top 2 2001 1 1 180 35

    Drawer 2 2002 1 1 200 35

    Leg Assembly 1 1002 1 1 100 25

    Legs 2 2003 4 1 250 65

    Side Rung 2 2004 2 1 50 65

    Connecting Rung 2 2005 1 1 110 65

    The MRP Output Table

    1Table Lead Time = 1

    Week Number Overdue 1 2 3 4 5 6 7 8

    Master Production Schedule 0 0 180 180 100 0 0 0

    Scheduled Receipts 0 0 0 0 0 0 0 0

    On Hand 50 50 50 0 0 0 0 0

    Net Requirements 0 0 130 180 100 0 0 0

    Planned Order Receipts 0 0 130 180 100 0 0 0

    Planned Order Releases 0 0 130 180 100 0 0 0 0

    2

    Top Assembly Lead Time = 2

    Week Number Overdue 1 2 3 4 5 6 7 8Gross Requirements 0 130 180 100 0 0 0 0

    Scheduled Receipts 0 100 0 0 0 0 0 0

    On Hand 50 50 20 0 0 0 0 0

    Net Requirements 0 0 160 100 0 0 0 0

    Planned Order Receipts 0 0 160 100 0 0 0 0

    Planned Order Releases 0 160 100 0 0 0 0 0 0

    3

    Table Top Lead Time = 1

    Week Number Overdue 1 2 3 4 5 6 7 8

    Gross Requirements 160 100 0 0 0 0 0 0

    Scheduled Receipts 0 0 0 0 0 0 0 0

    On Hand 180 20 0 0 0 0 0 0

    Net Requirements 0 80 0 0 0 0 0 0

    Planned Order Receipts 0 80 0 0 0 0 0 0

    Planned Order Releases 0 80 0 0 0 0 0 0 0

    Figure 8.20 MRP model for the kitchen table example.

  • 8/12/2019 Energy Business Modelling

    21/29

    47

    48

    49

    50

    51

    52

    53

    54

    55

    56

    57

    58

    59

    60

    61

    62

    6364

    65

    66

    67

    68

    69

    70

    71

    72

    73

    74

    75

    76

    77

    78

    79

    80

    81

    82

    83

    84

    85

    86

    87

    88

    89

    90

    91

    92

    93

    94

    95

    96

    A B C D E F G H I J K L

    4

    Drawer Lead Time = 1

    Week Number Overdue 1 2 3 4 5 6 7 8

    Gross Requirements 160 100 0 0 0 0 0 0

    Scheduled Receipts 0 0 0 0 0 0 0 0

    On Hand 200 40 0 0 0 0 0 0

    Net Requirements 0 60 0 0 0 0 0 0

    Planned Order Receipts 0 60 0 0 0 0 0 0

    Planned Order Releases 0 60 0 0 0 0 0 0 0

    5

    Leg Assembly Lead Time = 1

    Week Number Overdue 1 2 3 4 5 6 7 8

    Gross Requirements 0 130 180 100 0 0 0 0

    Scheduled Receipts 0 0 0 0 0 0 0 0

    On Hand 100 100 0 0 0 0 0 0

    Net Requirements 0 30 180 100 0 0 0 0Planned Order Receipts 0 30 180 100 0 0 0 0

    Planned Order Releases 0 30 180 100 0 0 0 0 0

    6

    Legs Lead Time = 1

    Week Number Overdue 1 2 3 4 5 6 7 8

    Gross Requirements 120 720 400 0 0 0 0 0

    Scheduled Receipts 0 100 0 0 0 0 0 0

    On Hand 250 130 0 0 0 0 0 0

    Net Requirements 0 490 400 0 0 0 0 0

    Planned Order Receipts 0 490 400 0 0 0 0 0

    Planned Order Releases 0 490 400 0 0 0 0 0 0

    7

    Side Rung Lead Time = 1

    Week Number Overdue 1 2 3 4 5 6 7 8

    Gross Requirements 60 360 200 0 0 0 0 0

    Scheduled Receipts 10 0 0 0 0 0 0 0 0

    On Hand 50 0 0 0 0 0 0 0

    Net Requirements 10 360 200 0 0 0 0 0

    Planned Order Receipts 10 360 200 0 0 0 0 0

    Planned Order Releases 10 360 200 0 0 0 0 0 0

    8

    Connecting Rung Lead Time = 1 Week Number Overdue 1 2 3 4 5 6 7 8

    Gross Requirements 30 180 100 0 0 0 0 0

    Scheduled Receipts 0 0 0 0 0 0 0 0

    On Hand 110 80 0 0 0 0 0 0

    Net Requirements 0 100 100 0 0 0 0 0

    Planned Order Receipts 0 100 100 0 0 0 0 0

    Planned Order Releases 0 100 100 0 0 0 0 0 0

    Figure 8.20 MRP model for the kitchen table example.

  • 8/12/2019 Energy Business Modelling

    22/29

    1

    2

    3

    4

    5

    6

    7

    8

    9

    10

    11

    12

    13

    14

    15

    16

    1718

    19

    20

    21

    22

    23

    24

    25

    26

    27

    28

    2930

    31

    32

    33

    34

    35

    36

    37

    38

    39

    40

    41

    42

    43

    44

    45

    46

    M N

    Figure 8.20 MRP model for the kitchen table example.

  • 8/12/2019 Energy Business Modelling

    23/29

    47

    48

    49

    50

    51

    52

    53

    54

    55

    56

    57

    58

    59

    60

    61

    62

    6364

    65

    66

    67

    68

    69

    70

    71

    72

    73

    74

    75

    76

    77

    78

    79

    80

    81

    82

    83

    84

    85

    86

    87

    88

    89

    90

    91

    92

    93

    94

    95

    96

    M N

    Page-break

    Figure 8.20 MRP model for the kitchen table example.

  • 8/12/2019 Energy Business Modelling

    24/29

    47

    48

    49

    50

    51

    52

    53

    54

    55

    56

    57

    58

    59

    60

    61

    62

    63

    64

    6566

    67

    68

    69

    70

    71

    72

    73

    74

    75

    76

    77

    78

    79

    80

    81

    82

    83

    84

    85

    86

    87

    88

    89

    9091

    92

    93

    94

    95

    96

    A B C D E F G H I J K L

    4

    Drawer Lead Time = 1

    Week Number Overdue 1 2 3 4 5 6 7 8

    Gross Requirements 160 100 0 0 0 0 0 0

    Scheduled Receipts 0 0 0 0 0 0 0 0

    On Hand 200 40 0 0 0 0 0 0

    Net Requirements 0 60 0 0 0 0 0 0Planned Order Receipts 0 60 0 0 0 0 0 0

    Planned Order Releases 0 60 0 0 0 0 0 0 0

    5

    Leg Assembly Lead Time = 1

    Week Number Overdue 1 2 3 4 5 6 7 8

    Gross Requirements 0 130 180 100 0 0 0 0

    Scheduled Receipts 0 0 0 0 0 0 0 0

    On Hand 100 100 0 0 0 0 0 0

    Net Requirements 0 30 180 100 0 0 0 0

    Planned Order Receipts 0 30 180 100 0 0 0 0

    Planned Order Releases 0 30 180 100 0 0 0 0 0

    6

    Legs Lead Time = 1

    Week Number Overdue 1 2 3 4 5 6 7 8

    Gross Requirements 120 720 400 0 0 0 0 0

    Scheduled Receipts 0 100 0 0 0 0 0 0

    On Hand 250 130 0 0 0 0 0 0

    Net Requirements 0 490 400 0 0 0 0 0

    Planned Order Receipts 0 490 400 0 0 0 0 0

    Planned Order Releases 0 490 400 0 0 0 0 0 0

    7

    Side Rung Lead Time = 1

    Week Number Overdue 1 2 3 4 5 6 7 8

    Gross Requirements 60 360 200 0 0 0 0 0

    Scheduled Receipts 10 0 0 0 0 0 0 0 0

    On Hand 50 0 0 0 0 0 0 0

    Net Requirements 10 360 200 0 0 0 0 0

    Planned Order Receipts 10 360 200 0 0 0 0 0

    Planned Order Releases 10 360 200 0 0 0 0 0 0

    8

    Connecting Rung Lead Time = 1

    Week Number Overdue 1 2 3 4 5 6 7 8

    Gross Requirements 30 180 100 0 0 0 0 0Scheduled Receipts 0 0 0 0 0 0 0 0

    On Hand 110 80 0 0 0 0 0 0

    Net Requirements 0 100 100 0 0 0 0 0

    Planned Order Receipts 0 100 100 0 0 0 0 0

    Planned Order Releases 0 100 100 0 0 0 0 0 0

    Figure 8.20 (cont.)

  • 8/12/2019 Energy Business Modelling

    25/29

    1

    2

    3

    45

    6

    7

    8

    9

    10

    11

    12

    13

    14

    15

    16

    17

    18

    19

    20

    21

    22

    23

    24

    25

    26

    27

    28

    29

    30

    31

    32

    33

    34

    35

    36

    37

    38

    A B C D E F G H I J K L M

    Example 9. 14 - A Model for the Part Period Balancing (PPB) Method

    Input Ordering (or Setup) Cost = 200 User input cells

    Unit holding cost = 1.00 are shadedEconomic part period (EPP) = 200

    REQP 150 100 150 0 50 75 100 25 20

    Per iod, P 1 2 3 4 5 6 7 8 9

    Weighted REQi 0 100 300 0 200 375 600 175 160

    CUMi 0 100 400 400 600 975 1575 1750 1910

    (CUMi- EPP)/EPP -1.0 -0.5 1.0 1.0 2.0 3.9 6.9 7.8 8.6

    0.5 1.0 0.5 1.0 1.0 2.0 3.9 6.9 7.8 8.6

    Order Data = 150 100

    0 Answer: Place an order for 250 uni ts in per iod 1

    New Factor, NFi 0 0 1 2 3 4 5 6 7

    Weighted REQi -150 -100 0 0 100 225 400 125 120

    CUMi 0 0 0 0 100 325 725 850 970

    (CUMi- EPP)/EPP -1.0 -1.0 -1.0 -1.0 -0.5 0.6 2.6 3.3 3.9

    0.5 1.0 1.0 1.0 1.0 0.5 0.6 2.6 3.3 3.9

    Order Data = 150 0 50

    2 Answer: Place an order for 200 uni ts in per iod 3

    New Factor, NFi 0 0 0 0 0 1 2 3 4

    Weighted REQi

    -150 -100 -150 -1 -50 0 100 50 60

    CUMi 0 0 0 0 0 0 100 150 210

    (CUMi- EPP)/EPP -1.0 -1.0 -1.0 -1.0 -1.0 -1.0 -0.5 -0.3 0.1

    0.1 1.0 1.0 1.0 1.0 1.0 1.0 0.5 0.3 0.1

    Order Data = 75 100 25 20

    5 Answer: Place an order for 220 uni ts in per iod 6

    New Factor, NFi 0 0 0 0 0 0 0 0 0

    Copy cell range B11:L17 repeatedly down the spreadsheet, placing the cursor in cells B19,

    B27. until the 'New Factor, NFi' row contains nothing but zeros (e.g. see row 33 above).

    Figure 8.21 Model for the part-period balancing (PBB) method.

    (Note that this model has been modified)

  • 8/12/2019 Energy Business Modelling

    26/29

    1

    2

    3

    4

    5

    6

    7

    8

    9

    A B C D E F G H

    Product No. in Product Year Cash

    name stock price flow

    Gizmo 10 10.00 1 1

    Gadget 25 12.50 2 4

    Widget 8 20.00 3 8

    Sprocket 40 4.50 4 16

    5

    Sample F igur e

  • 8/12/2019 Energy Business Modelling

    27/29

    10

    11

    12

    13

    14

    15

    16

    17

    A B C D E F G H

    Column(B3) = 2 Row(B3) = 3

    Column(D5:D9) = 4 Row(D5:D9) = 5

    INDEX(B4:D7,2,3) = 12.50 NORMSINV(0.95) =

  • 8/12/2019 Energy Business Modelling

    28/29

    1

    2

    3

    4

    5

    6

    7

    8

    9

    I

  • 8/12/2019 Energy Business Modelling

    29/29

    10

    11

    12

    13

    14

    15

    16

    17

    I

    1.6449