Low-Cost Tweaks Yield Big-Time Savings

Once Jack Dale Associates (JDA) quantified mechanical-system interactions for Texaco's data center, specified techniques were employed to upgrade the plant while avoiding disruptions to data-processing operations. Total construction costs for chiller-plant renovations commissioned by JDA were less than $600,000.

11/01/2000


Once Jack Dale Associates (JDA) quantified mechanical-system interactions for Texaco's data center, specified techniques were employed to upgrade the plant while avoiding disruptions to data-processing operations. Total construction costs for chiller-plant renovations commissioned by JDA were less than $600,000.

Procedures outlined by the engineering team improved energy efficiency and continue to save the petrochemical company more than $100,000 per year in utility costs. The design not only solved operating problems, but also improved the facility's ability to increase its chilled-water reserve for future expansions. Best of all, the upgrades reduced energy consumption. Key features include:

 

The upgrades help set system demand and to ensure that only the required amount of chilled water is distributed.

Before JDA began work on the project, Texaco had received a number of proposals for resolving the facility's system problems. The least onerous of the proposals would have required a two-week shutdown of the entire 5,000-ton chiller plant and over $2 million to complete.

Table 1 - Existing HVAC System Parameters


TimeBypass positionB riser flowB supply tempB return tempMain CHW supply temp FChilled water flow (gpm)Flow to labs (gpm)BAX flow (gpm)East-West riser flow (gpm)Main return header pressure (psi)Main supply header pressure (psi)IBM CDU flow (L/M)

13:00

Closed

1584

44.6

52.7

43.6

2778

414

617

1610

66

65

190

13:15

10% open

1665

44.7

52.1

43.7

2787

426

626

1661

65

64

190

13:20

15% open

1634

44.6

52.1

43.6

2737

432

637

1655

65

65

190

13:30

20% open

1666

45.0

52.0

43.7

2645

505

636

1704

65

65

200

13:38

25% open

1686

45.0

52.1

43.9

2655

504

630

1713

65

66

200

13:43

35% open

1669

44.4

52.3

44.0

2635

504

637

1728

65

66

200

13:49

Full open

1662

44.6

52.7

44.3

2671

502

630

1778

66

67

200

13:57

Full open

1363

44.1

54.5

44.3

2631

513

627

1864

68

68

145

14:08

Full open

1333

43.5

54.1

43.8

2611

517

635

930

69

70

130


Table 2 - Savings from Mechanical Plant Re-engineering


Original designRe-engineered design

HP

kW

HP

kW

Subtotal:

972

611

Subtotal:

223

118

Chiller loads:

2,200

1,760

Chiller loads:

1,600

1,280

Total HP & kW:

3,172

2,371

Total HP & kW:

1,832

1,398

Dead head factor:

0.90

Pump kW saved:

973

Total kW Demand:

2,134 kW

Total kW demand:

1,398

Use factor:

0.80

Use factor:

0.80

Annual pump utility cost:

$235,462

Annual pump utility cost:

$45,530

Added utility cost for new office space:

$79,684

Net annual utility savings after chiller plant renovations:

$110,248


Average cost per kWh: 0.055 $/kWh





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