High-Performance Chilled Water Systems - Illinoi

1. High Performance
Chilled Water
Systems
Mick Schwedler, PE, LEED® AP
Manager
Applications Engineering
Trane
© 2011 Ingersoll Rand

2. Normal Performance
Chilled Water Systems
 ASHRAE/IESNA 90.1 (LEED Prerequisite)
 System configuration
 Design parameters
 System control

3. ASHRAE Standard
90.1-2007 Purpose
“… Provide minimum
requirements for the energy-
efficient design of buildings
except low-rise residential
buildings”

4. Purpose of
ANSI/ASHRAE/IESNA
Standard 90.1-2010
To establish minimum energy
efficiency requirements of buildings,
other than low-rise residential
buildings for:
1. design, construction, and a plan for
operation and maintenance, and
2. Utilization of on-site renewable
energy resources.

5. Publication and Final
Savings Estimates
 Performed by Pacific Northwest National
Laboratory (PNNL)
 Savingsof 90.1-2010 compared to
90.1-2004
 Savings shared are modeled as of
January 2011
 Includeventilation changes in ASHRAE 62.1
between 1999 and 2007 versions

6. 90.1 Progress Indicator
 Including receptacle loads in modeling
 Including receptacle load in % savings
calculation
Energy cost savings % Energy savings
%
Ventilation rate changes
between 62.1-1999 24.0 25.5
and 62.1-2007

7. 90.1 Progress Indicator
Excluding receptacle loads in % savings
calculation only
 Including receptacle loads in modeling
 Excluding receptacle load in % savings
calculation Energy cost savings % Energy savings
%
Ventilation rate changes
between 62.1-1999 30.1 32.6
and 62.1-2007

8. LEED Energy and
Atmosphere
 LEED 2009
 10% energy cost savings beyond 90.1-2007
 LEED 2012
 Public Review 2: September 2011
 EA Prerequisite: 10% average energy cost and source
energy savings beyond 90.1-2010 (new construction)
 EA Credit: Credit for reductions beyond 10%

9. 90.1-2010
Chiller Efficiencies
Paths A & B Before 1/1/2010 As of 1/1/2010c Test
Procedureb
Equipment Type Size CategoryUnits Path A Path Bd
Full Full Full
Load IPLV Load IPLV Load IPLV ARI 550/590
<150 tons EER ≥9.562 ≥10.416 ≥9.562 ≥12.50 NA NA
Air-cooled
≥150 tons EER ≥9.562 ≥10.416 ≥9.562 ≥12.75 NA NA
<75 tons kW/ton ≤0.780 ≤0.630 ≤0.800 ≤0.600
≥75 tons and < ≤0.790 ≤0.676
Water Cooled kW/ton ≤0.775 ≤0.615 ≤0.790 ≤0.586
150 tons
Electrically Operated,
≥150 tons and
Positive Displacement kW/ton ≤0.717 ≤0.627 ≤0.680 ≤0.580 ≤0.718 ≤0.540
< 300 tons
≥300 tons kW/ton ≤0.639 ≤0.571 ≤0.620 ≤0.540 ≤0.639 ≤0.490
<150 tons kW/ton ≤0.703 ≤0.669
≥150 tons and ≤0.634 ≤0.596 ≤0.639 ≤0.450
Water Cooled kW/ton ≤0.634 ≤0.596
< 300 tons
Electrically Operated,
≥300 tons and
Centrifugal kW/ton ≤0.576 ≤0.549 ≤0.600 ≤0.400
< 600 tons ≤0.576 ≤0.549
≥600 tons kW/ton ≤0.570 ≤0.539 ≤0.590 ≤0.400
Must meet both full and part load requirements

10. Heat rejection equipment
 Fan speed control 7.5 and
greater
 Capability to operate at 2/3
fan speed or less
 Exceptions
 Climates > 7200 CDD50
(e.g. Miami)
 1/3 of fans on multiple fan
application

11. Hydronic system
design and control
 Pump isolation
 Chilled and hot water reset if >300,000
Btuh
 Exception: Variable flow systems that
reduce pumping energy

12. 90.1-2007
Hydronic System
Design & Control
These provisions apply if pump system
power > 10 hp:
 Must be variable flow unless …
 Pump power ≤ 75 hp
 ≤ 3 Control valves
 Limit demand of individual variable-flow
pumps to 30% of design wattage at 50%
flow (e.g., use VSD)
 Pump head > 100 ft
 Motor > 50 hp

13. Waterside
Energy Recovery required
 Service Water Heating
 24 hrs per day and
 Heat rejection > 6 MMBtuh and
 SWH load 1 MMBtuh
 Recover smaller of
 60% of heat rejection
 Preheat water to 85°F

14. Configuration
Normal Performance
Chilled Water
production
pumps
distribution
pump
production
loop
distribution
loop
two-way valve

15. Design Parameters
Normal Performance
Chilled Water Plant
 ARI 550/590 Standard Conditions
 44°F chilled water
 2.4 gpm/ton chilled water (10°F T)
 3.0 gpm/ton condenser water
(10°F [9.3] T)

16. Control
Normal Performance
Chilled Water Plant
 Chilled water distribution pump
P at most remote load
 Cooling tower fans
 55°F (as cold as possible)
 Constant speed condenser water pumps
All these “normal” assumptions will be examined

17. High Performance
Chilled Water Plants
 Standard high performance
 Reduced flow rates, increased ∆Ts
 Variable primary flow
 Advanced high performance
 Equipment capabilities
 System configurations
 System control

18. a history of
Chiller Performance
8.0 centrifugal
>600 tons
chiller efficiency, COP
screw
6.0 150-300 tons
scroll
<100 tons
4.0
reciprocating
<150 tons
2.0
0.0
ASHRAE Standard 90 NBI “best”
90-75 90-75 90.1-89 90.1-99 available
(1977) (1980)

19. chilled water plant design …
Provocation
Are our “rules of thumb” …
 44 F chilled water supply
 10 F T for chilled water system
 3 gpm/ton condenser water flow
… in need of repair?

20. High Performance
Design Parameters
 ASHRAE GreenGuide and CoolTools™
 Chilled water T: 12°F to 20 °F
 Condenser water T:
12°F to 18 °F (multi-stage)
 Kelly and Chan
 Chilled water T: 18°F
 Condenser water T: 14.2°F
(3.6 - 8.3% energy savings in various
climates)

21. chilled water plant …humid climate
Base Design: 450 Tons
 0.5% design  Coil, valve and chilled
wet bulb: 78 F water piping pressure
drop: 80 ft
 Entering condenser
water temperature  Condenser water piping
(ECWT): 85 F pressure drop: 30 ft
 Evaporator and  Pump efficiency: 75%
condenser  Pump motor
temperature efficiency: 93%
differences: 10 F

22. traditional design …humid climate
System Energy
Consumption
350
Energy Consumption, kW
300
250
200
150 Tower
Condenser Water Pump
100 Chilled Water Pump
Chiller (100% Load)
50
0
2.4/3.0
Chilled / Condenser Water Flows, gpm/ton

23. traditional vs. low-flow design …
System Summary At
Full Load
350
Energy Consumption, kW
300
250
200
150 Tower
Condenser Water Pump
100 Chilled Water Pump
Chiller (100% Load)
50
0
2.4/3.0 1.5/2.0
Chilled / Condenser Water Flows, gpm/ton

24. comparison …humid climate
System Summary At
75% Load
350
Energy Consumption, kW
300
250
200
150 Tower
Condenser Water Pump
100 Chilled Water Pump
Chiller (75% Load)
50
0
2.4/3.0 1.5/2.0
Chilled / Condenser Water Flows, gpm/ton

25. comparison …humid climate
System Summary At
50% Load
350
Energy Consumption, kW
300
250
200
150 Tower
Condenser Water Pump
100 Chilled Water Pump
Chiller (50% Load)
50
0
2.4/3.0 1.5/2.0
Chilled / Condenser Water Flows, gpm/ton

26. comparison …humid climate
System Summary At
25% Load
350
Energy Consumption, kW
300
250
200
150 Tower
Condenser Water Pump
100 Chilled Water Pump
Chiller (25% Load)
50
0
2.4/3.0 1.5/2.0
Chilled / Condenser Water Flows, gpm/ton

27. traditional vs. low-flow design
…humid climate
Savings Summary
20.0
Operating Cost Savings, %
16.5%
10.3%
10.0
6.7%
3.8%
0
25% 50% 75% 100%
Load

28. High Performance
Design Parameters
kWh/ton/year
600
Chilled water
400 pump
200 Chiller
0
41/16 42/14 43/12 44/10
Chilled water supply
temperature/DeltaT

29. Pipe Size Example
90.1-2010 Table 6.5.4.5
 800 ton system
 3,000 hours of operation
 Chilled water, variable flow
 Condenser water, constant flow
Past Design ASHRAE GreenGuide
Practice
∆T Flow Pipe ∆T Flow Pipe
(°F) (gpm) Size (°F) (gpm) Size
Chilled 10 1920 10 16 1200 8
Water
Condenser 9.4 2400 14 14 1600 12
Water

30. High Performance
Design Options
Either …
 Take full energy (operating
cost) savings
Or …
 Reduce piping size and cost
Experienced designers use pump,
piping and tower savings to select an
even more efficient chiller

31. Reduced flow works for
all chiller manufacturers
 Logan Airport - Boston:
 $426,000 Construction cost savings
 7.3% operating cost savings
 Large Chemical Manufacturer -Greenville
 $45,000 Excavation and concrete savings
 6.5% Operating cost savings
 Computer Manufacturer - San Francisco
 Existing tower, pipe savings
 2% Operating cost savings (tower not changed)

32. Low flow works for
retrofit applications
 Chilled water side
 Coil
 It’s a simple heat transfer device
 Reacts to colder entering water
by returning it warmer
 Ideal for system expansion

33. Low flow works for
retrofit applications
Condenser side retrofit opportunity
 Chiller needs to be
replaced
 Cooling needs have
increased by 50%
 Cooling tower was
replaced two years ago
 Condenser pump and
pipes are in good shape

34. Condenser side
retrofit opportunity
Existing Retrofit
Capacity (tons) 500 750
Flow rate (gpm) 1500 1500
Condenser Entering Water 85 88
Temperature (F)
Condenser Leaving Water 95 103
Temperature (F)
Design Wet Bulb (F) 78 78

35. Humid climates
Low flow works for
short piping runs too
Condenser Water Side Only - original
350.0
300.0
Energy Consumption (kWh)
250.0
200.0
3.0 gpm/ton
2.0 gpm/ton
150.0
100.0
50.0
0.0
25% 50% 75% 100%
System Load

36. Humid climates
Low flow works for
short piping runs too
Condenser Water Side Only
ZERO piping pressure drop
350.0
300.0
Energy Consumption (kWh)
250.0
200.0
3.0 gpm/ton
2.0 gpm/ton
150.0
100.0
50.0
0.0
25% 50% 75% 100%
System Load

37. High Performance
Design Parameters
 Low flow benefits systems - no
matter whose chiller is being
used
 Low flow works extremely
well on existing systems
 Low flow works on short
piping runs

38. always, always,
Always Remember …

39. Oh, by the way...
You may also do this with air

40. Variable-Primary-Flow
Systems
variable-flow
pumps
check
valves
control
valve

41. VPF Savings
 First cost: 4-8%
 Annual energy: 3-8%
 Life-cycle cost: 3-5%
http://www.arti-21cr.org/ARI/util/showdoc.aspx?doc=1085

42. Flow requirements
VPF System
 Limits (consult manufacturer)
 Absolute flows - Minimum and maximum
 Flow rate changes
 2% of design flow per minute
not good enough
 10% of design flow per minute borderline
 30% of design flow per minute
many comfort cooling applications
 50% of design flow per minute
best
 Always need a way to ensure minimum
flow (bypass)

43. Chiller Control
V a ria b le W a te r F lo w
130 1500
120 1300
110 1100
100 900
Water Temp [degF]
90 700
E vaporator W ater F low
Flow [gpm]
80 500
70 300
60 100
50 E vap E ntering W ater T em p -100
40 -300
E vap Leaving W ater T em p
30 -500
3:50:00 3:55:00 4:00:00 4:05:00 4:10:00
T im e (h o u r:m in :s e c )

44. More information
VPF System
 Http:/trane.com/commercial
/library/newsletters.asp (1999 and 2002)
 “Primary-Only vs. Primary-Secondary Variable Flow
Systems,” Taylor, ASHRAE Journal, February 2002
 “Don’t Ignore Variable Flow,” Waltz, Contracting
Business, July 1997
 “Comparative Analysis of Variable and Constant
Primary-Flow Chilled-Water-Plant Performance,”
Bahnfleth and Peyer, HPAC Engineering, April 2001
 “Campus Cooling: Retrofitting Systems,”
Kreutzmann, HPAC Engineering, July 2002

45. High Performance
Chilled Water Plants
 Standard high performance
 Reduced flow rates, increased ∆Ts
 Variable primary flow
 Advanced
 Equipment capabilities
 System configurations
 System control

46. Equipment Capabilities
High Performance
Chilled Water Plant
 Constant speed
 0.570 FL / 0.479 IPLV
 Higher efficiency “same price” options
 Variable speed (spend money on drive)
 Constant speed (spend money on copper)
 Purchase both a drive and more heat
exchange surface
 Down to 0.45 kW/ton FL available (22%
reduction)

47. Same-price Chiller:
Example Performance
Option Full Load IPLV
(kW/ton) (kW/ton)
VSD 0.572 0.357
High Efficiency 0.501 0.430

48. Same-price Chiller:
Example Performance
600-ton Replacement Chiller Performance
400
350
300
High_efficiency_85°F
250 VSD_85°F
High_efficiency_75°F
kW
200
VSD_75°F
150 High_efficiency_65°F
VSD_65°F
100
50
0
0% 20% 40% 60% 80% 100%
% Load

49. Example
 Office building
 Two 400-ton chillers
 Comparisons
 Base system - constant speed
 AFD on both chillers
 High efficiency for both chillers
 AFD on one chiller
 High efficiency for one chiller

50. What is the actual
utility rate?
 Utility costs
 ‘Combined’ utility rates ($0.10 / kWh)
 Actual utility rates ($12 / kW and $0.06 /
kWh)

51. Utility rate comparison
Simple paybacks, humid climate
Combined rate Actual rate
on one AFD 6.1 10.8
chiller
High efficiency 6.3 7.7
on both AFD 7.2 12.7
chillers
High efficiency 7.1 8.3
Using incorrect “combined” rate
leads to incorrect decisions

52. Rule 1
Use actual utility rates

53. Temperate climate
with economizer
Annual operating cost Simple payback
$100,000 30
$80,000 25
20
$60,000
15
$40,000
10
$20,000 5
0
Base case AFD on High efficiency AFD on High efficiency
both chillers both chillers one chiller one chiller
Chiller plant operating cost
Simple payback

54. Temperate climate,
no economizer
Annual operating cost Simple payback
$100,000 12
$80,000 10
8
$60,000
6
$40,000
4
$20,000 2
0
Base case AFD on High efficiency AFD on High efficiency
both chillers both chillers one chiller one chiller
Chiller plant operating cost
Simple payback

55. Humid climate,
no economizer
Annual operating cost Simple payback
$100,000 14
$80,000 12
10
$60,000
8
$40,000
6
$20,000 4
2
Base case AFD on High efficiency AFD on High efficiency
both chillers both chillers one chiller one chiller
Chiller plant operating cost
Simple payback

56. Dry climate with
economizer
Annual operating cost Simple payback
$100,000 18
16
$80,000 14
12
$60,000 10
8
$40,000
6
4
$20,000
2
0
Base case AFD on High efficiency AFD on High efficiency
both chillers both chillers one chiller one chiller
Chiller plant operating cost
Simple payback

57. Rule 2
Model ROI of
each investment

58. Guidance:
VSD or High Efficiency?
 High efficiency  VSD
 Significant demand  Many hours at low
charges, especially condenser water
ratchet charges temperature – and low
load
 Climates where the
wet bulb doesn’t vary  Perhaps only on one
substantially chiller
 Multiple chillers in the  Factor replacement
plant cost of VSD when
performing life cycle
 Economizer that assessment
reduces low load/low
lift operating hours

59. High Performance
Chilled Water Plants
 Standard high performance
 Reduced flow rates, increased ∆Ts
 Variable primary flow
 Advanced
 Equipment capabilities
 System configurations
 System control

60. VPF System
Minimum flow and bypass control
 Single chiller
 Retrofit
Controller
P
P

61. What may not be a
good VPF application?
 Two packaged chillers
 Limited evaporator configurations
 Assume minimum flow is about 1.2 gpm/ton
 In parallel
 Wide ∆T (low flow)
 e.g 18°F ∆T is 1.33 gpm/ton
 Why isn’t it a good application?
 Flow can only be turned down 10%

62. Variable-Volume Pumping System
(series chillers)
48.4°F
Upstream chiller operating at higher
temperature is more efficient
41°F
57°F
Bypass alternatives

63. Series Chillers
Manual service bypass

64. Series Chiller
Advantages
 Simplifies pumping and  Simple preferential
sequencing loading of chillers
 No flow rate transitions  Adjust upstream
chiller’s setpoint
 Makes VPF simple
 Upward to unload
 Downward to load
 Upstream chiller
operates at elevated
temperature
 Efficiency increases
 Capacity increases
 10% or more for
absorption

65. High Performance
Chilled Water Plants
 Standard high performance
 Reduced flow rates, increased ∆Ts
 Variable primary flow
 Advanced
 Equipment capabilities
 System configurations
 System control

66. Control
Normal Performance
Chilled Water Plant
 Chilled water distribution pump
P at most remote sensor
 Cooling tower fans
 55°F (as cold as possible)
 Somewhere else
 Constant volume condenser water pumps

67. High Performance
Chilled Water Pump
Control
Communicating
BAS Pump
Pump Speed Valve position
Pressure
Sensor

68. pump-pressure optimization
Control Logic
90.1-2007 Addendum ak
Increase pump static pressure setpoint
75%
Position (% open)
of critical valve No action
65%
Reduce pump static pressure setpoint

69. High Performance
Chiller-Tower Control
Plant Power vs CWS
Chillers cannot meet load
1,200.0
Lowest condenser water above this condenser water
temperature available from temperature
tower at this load and wet-bulb
temperature
1,000.0
1,550 tons, 65°F Wet-bulb
T t
800.0
1,160 tons, 59°F Wet-bulb
Power (kW)
T
600.0
730 tons, 54°F Wet-bulb Temperature
400.0 Optimal operation
200.0
0.0
60
62
64
66
68
70
72
74
76
78
80
82
84
86
88
Condenser Water Setpoint (°F)
Hydeman, et. al. Pacific Gas and Electric. Used with permission.

70. Cooling tower basics
Fan energy consumption
% Full load power
100
80
60
40
20
0
0 20 40 60 80 100
% Airflow

71. cooling tower performance factors
Approach and Wet Bulb
16.0
tower approach, deg
12.0
8.0
100% load
approach = 9
4.0 50% load
approach = 4
0.0
50 60 70 80
ambient wet bulb, °F

72. simple case: constant water flow
Operating Dependencies
 Wet bulb  Load
 Condenser water  Condenser water
temperature temperature
 Load  Chiller design
 Tower design

73. condenser water control
“Normal” Setpoint
 Hot?
e.g., 85°F, minimizes tower
energy consumption
 Cold?
e.g., 55°F, minimizes chiller
energy consumption
 Optimized?

74. optimal condenser water control
Chiller–Tower Interaction
400
total
energy consumption, kW
300
chiller
optimal
200 control point
100
tower
0
72 74 76 78 80 82 84
condenser water temperature, °F

75. High Performance
Chiller-Tower Control
 Braun, Diderrich
 Hydeman, Gillespie,
Kammerud
 Schwedler,
ASHRAE Journal
 Cascia
 Crowther and
Furlong

76. chiller–tower optimization
An Example …
 720,000 ft² hotel
 2 chillers, 2 tower cells
 Control strategies
 Make leaving-tower water cold
as possible (55F)
 Optimize system operation
 Entering-condenser setpoint
equals design …
85°F for humid climates
80°F for dry climates

77. chiller–tower control strategies
North America
350K
control strategy:
annual operating cost, $ USD
300K 55°F lvg tower
optimal control
250K
design ECWT
200K
150K
100K
50K
0
Mexico City Orlando San Diego Toronto

78. chiller–tower control strategies
Global Locations
500K
control strategy:
annual operating cost, $ USD
55°F lvg tower
optimal control
400K
design ECWT
300K
200K
100K
0
Dubai Paris Sao Paulo Singapore

79. operating cost savings, %
0
2
4
6
8
10
12
Dubai 14
Paris
Sao Paulo
Singapore
Mexico City
location
chiller–tower optimization
Orlando
San Diego
Operating Cost Savings
Toronto

80. chiller–tower optimization
Perspective on Savings
For centrifugal chillers ≥ 300 tons, ASHRAE
90.1 requires …
 0.576 kW/ton at full load
 0.549 kW/ton at IPLV
… using ARI standard rating conditions

81. chiller–tower optimization
Perspective on Savings
Equivalent
Savings, % chiller efficiency
0.0 0.576
2.8 0.560
4.5 0.550
6.2 0.540
14.0 0.495

82. Where’s the Meter?
On the
BUILDING

83. chiller–tower optimization
Finding “Near Optimal”
 Tower design
(flow rate, range, approach)
 Chiller design
 Refrigeration cycle
(vapor compression vs. absorption)
 Compressor type
 Capacity control (variable-speed drive)
 Changing conditions
(chiller load, ambient wet bulb)

84. chiller–tower optimization
Necessities
 System-level
controls
 Variable-frequency
drive
on tower fans
 High-quality
dewpoint sensor

85. Number of chillers
operating
 Operate one at nearly full load or two at
part load?
 Examine IPLV assumptions

86. VSDs and centrifugal chillers
A Closer Look at IPLV
Load Weighting ECWT kW/Ton
100% 0.01 85°F 0.572
75% 0.42 75°F 0.420
50% 0.45 65°F 0.308
25% 0.12 65°F 0.372
VSDs improve part-lift performance, so running two chillers
with VSDs at part load seems more efficient than one chiller at
double the same load, but …is dependent on condenser water
temperature

87. Chiller power only
45% Plant load
Operate 1 or 2 Chillers?
Chiller kW Only
350
1@90% Load
300
2@45% Load
250
Chiller kW
200
150
100
50
0
55 60 65 70 75 80 85
Available Tower Water Temperature (ºF)

88. Chillers plus pumps
45% Plant load
Operate 1 or 2 Chillers?
Chiller Plus Pump kW
400
1@90% Load
350
Chiller Plus Pump kW
2@45% Load
300
250
200
150
100
50
0
55 60 65 70 75 80 85
Available Tower Water Temperature (ºF)

89. Operate 1 or 2 chillers?
Run 1 or 2 VSD Chillers?
400
1@90% Load
350 2@45% Load
1@80% Load
Operate multiple chillers here,
300 2@40% Load
Total Chiller Plus Pump kW
otherwise single chiller
1@70% Load
250 2@35% Load
1@60% Load
200
2@30% Load
1@50% Load
150
2@25% Load
100
50
0
60 65 70 75 80 85
Available Tower Water Temperature (ºF)

90. Operate 1 or 2 chillers?
 45% plant load: One chiller until tower
temperature is < 65°F
 40% plant load: One chiller until tower
temperature is < 60°F
 35% plant load and below: One chiller

91. High Performance
Condenser Water Pump
Control – Variable?
 Pump speed limits
 Tower static lift
 Tower nozzles (minimum flow)
 Condenser minimum flow
 Pump speed reductions result in
 Increased leaving condenser water
temperature
 Decreased cooling tower effectiveness
 Possible chiller surge

92. High Performance
Condenser Water Pump
Control – Variable?
 The condenser water pump is the hardest
place to properly utilize a variable frequency
drive during operation
 There are successful installations

93. variable-flow condenser water
Pump Speed
 Determining minimum speed
 Variable flow affects:
 Pump
 Cooling tower
 Chiller

94. condenser water pump
Minimum Speed
Determinants:
 Minimum condenser flow
 Tower static lift
 Minimum tower flow
 Nozzle selection
 Performance

95. reducing flow & fan speed
Effect on System
fan speed
300
250
system power, kW
200
150
conditions:
100
• 70% load
• 50°F WB
50
0
50 60 70 80 90 100
condenser water flow, %

96. Varying fan and pump
speed together

97. variable condenser water flow
Guidance
 Can provide savings …
 Finding proper operating
points requires more time,
more fine-tuning
 Two-step process:
1 Reduce design pump power
2 Is variable condenser-water
flow still warranted?

98. ROI
High Performance
Chilled Water Plants
 EnergyPlus
 Non-bin
 Schematic
tools that
analyze in 30-
45 minutes
are available

99. High Performance
Chilled Water Plants
 Standard high performance
 Reduced flow rates, increased ∆Ts
 Variable primary flow
 Advanced high performance
 Equipment capabilities
 System configurations
 System control

100. High performance chilled water plant
Winchester Medical
Center

101. Medical Center
Winchester, Virginia
 Five 750-ton chillers  VFD’s on
 0.571 kW/ton full load  Chilled water pumps
 Chilled water  Cooling tower fans
58 to 42°F
 Condenser water
 Condenser water pumps
84 to 95°F
(missed opportunity)  Sophisticated control
system with lots of
 VFD’s
 Programming
 Variable primary flow
 Commissioning

102.  Owner
Center
 Operators
 Service provider
 Working together
 Controls provider
 Equipment provider
 Consulting engineer
Load (tons)
8/
8/
2
8/ 00 3
8/2 1
4
0.0
200.0
400.0
600.0
800.0
1000.0
1200.0
1400.0
8/8 00 3 :30
/2 1 3
8/ 00 3 :30
8/
2 12
8/ 00 3 :30
8/2 1
0 1:3
 Applications engineering
8/8 0 3 1 0
/2 0:3
8/ 00 3 0
8/
20 9 :3
8/ 0 3 0
8/2 8
:3
8/8 00 3 0
/2 7 :3
8/ 00 3 0
8/
2 6 :3
8/8 00 3 0
/2 5 :3
8/8 00 3 0
/2 4 :3
8/ 00 3 0
8/
2 3 :3
8/8 00 3 0
/2 2 :3
8/8 00 3 0
/ 1
8/ 200 :3 0
Time/Date
7/2 3
0
8/7 00 3 :3 0
/2 2 3
8/ 00 3 :30
7/
20 2 2
8/ 0 3 :30
7/2 2
1
8/7 00 3 :30
/2 2 0
0
8/ 0 3 :30
7/
2 19
8/7 00 3 :30
/2 1 8
8/7 00 3 :30
/2 17
Winchester Medical
8/ 00 3 :30
7/
20 1 6
0 3 :30
15
:3
0
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
Efficiency (kW/ton)
tons
kW/ton

103. Load (tons)
8/
8/
2
8/ 00 3
8/
2 14
0.0
200.0
400.0
600.0
800.0
1000.0
1200.0
8/ 00 3 :30
8/ 1400.0
2 13
8/ 00 3 :30
8/
2 12
8/ 00 3 :30
8/
20 1 1
0 :
8/ 3 1 30
8/
2 0:
8/ 00 3 30
8/
20 9 :3
8/ 0 3 0
8/
2 8 :3
8/ 00 3 0
8/
2 7 :3
8/ 00 3 0
8/
2 6 :3
8/ 00 3 0
8/
2 5 :3
8/ 00 3 0
8/
2 4 :3
8/ 00 3 0
8/
2 3 :3
Chiller plant
8/ 00 3 0
8/
2 2 :3
8/ 00 3 0
8/ 1
8/ 200 :3 0
Time/Date
7/
2 3
0
8/ 00 3 :3 0
7/
2 23
8/ 00 3 :30
7/
2 22
8/ 00 3 :30
7/
2 21
8/ 00 3 :30
7/
WMC - August 12
2 20
8/ 00 3 :30
7/
2 19
8/ 00 3 :30
7/
2 18
8/ 00 3 :30
7/
2 17
8/ 00 3 :30
7/
20 1 6
0 3 :30
15
:3
0
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
Efficiency (kW/ton)
tons
kW/ton

104. Tons
0.0
200.0
400.0
600.0
800.0
1000.0
1200.0
1400.0
1600.0
1/0/1900 0:00
1/0/1900 0:00
1/0/1900 0:00
1/0/1900 0:00
1/0/1900 0:00
9/1/2003 14:00
9/1/2003 19:30
9/2/2003 1:00
9/2/2003 6:30
9/2/2003 12:00
9/2/2003 17:30
9/2/2003 23:00
9/3/2003 4:30
Chiller plant
9/3/2003 10:00
9/3/2003 15:30
9/3/2003 21:00
Time
9/4/2003 2:30
9/4/2003 8:00
WMC - Sept 1-7
9/4/2003 13:30
9/4/2003 19:00
Weekly-Summary
9/5/2003 0:30
9/5/2003 6:00
9/5/2003 11:30
9/5/2003 17:00
9/5/2003 22:30
9/6/2003 4:00
9/6/2003 9:30
9/6/2003 15:00
9/6/2003 20:30
9/7/2003 2:00
9/7/2003 7:30
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.80
kW/ton
tons
kW/ton

105. Winchester Medical
Center - Mark Baker
 “Please use our data,
names, etc. We're
proud of our facility!”
 “By the way, we're
now operating @
-0.20 kW/ton. The
power company just
sent us our 1st check.
Ha..Ha…”

106. Remember...
Without controls,
it’s not a system.

107. The meter is on the
building!

108. It’s a great time to
be in this business!