the cost of using 1970’s era design concepts and “fear”in chilled water systems

The Cost of Using 1970’s EraDesign Concepts and “FEAR”in

Chilled Water Systems

WMGroup Engineers, P.C.

Presented By: Hemant Mehta, P.E.

What is the “FEAR”

• No change in design as previous design had no complains from client– No complain because no bench mark exists– Fear to take the first step to change the concepts to

use state of the art technology– Consultants sell time. Fear is any new concept will

take lots of time and it is not worth the effort

What are1970’s EraDesign Concepts?

• System Design for Peak load only• Primary/Secondary/Tertiary Pumping• 5°C (42°F) supply temperature• System Balancing• Circuit Setters• Band Aid solution for any Problem• Projected Demand way above reality• Oversized chiller, pumps TDH and everything else to

cover behind

State of the Art Plant concepts

• Plant designed for optimum operation for the year. Peak hours are less than 200 hours a year

• Variable flow primary pumping system • 3.3°C (38°F) or lower supply temperature• No System Balancing. Balancing is for a static system.• No Delta P valves – No Circuit Setters• No Band Aid solution for any Problem• Use chilled water system diversity (0.63) to Project

Cooling Demand• The total Chilled water pumping TDH even for a very

large system should not be more 63 meters(than 200 feet)

Selecting Equipment to Optimize EfficiencyChiller equipment is often erroneously selected based on peak load efficiency.

Peak load only occurs for a small number of hours of the year, as shown on the load duration curve below:

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000

Load

(Ton

s)

Hours

Jeddah Airport - Cooling Load Duration Curve

The Design of the Human Body

Heart (Variable Volume Primary Pump)

Lungs(Chillers)

Brain (Building End-Users)

Basic 1970’s Era Chiller Plant Design

Primary Pump Secondary Pump

Decoupler Line

Building Loads

Chiller

Current Design Used on Many Large District Chilled Water Systems

Primary Pump

Secondary Pump

Decoupler Line

Building Loads

Chiller

EnergyTransferStation

Building Pump

Modern Variable Volume Primary Chiller Plant Design

Building Loads

Chiller

Variable Speed Primary Pump

Lost Chiller Capacity Due to Poor ΔT

5°C (41°F)

No Flow Through Decoupler

13°C (55.5°F)

5°C (41°F)

13°C (55.5°F)

150 L/sec (2,400 gpm)

150 L/sec (2,400 gpm)

150 L/sec (2,400 gpm)

150 L/sec (2,400 gpm)

Chiller sees a ΔT of 8°C (14.5°F) at a flow of 150 L/sec (2,400 gpm)

The chiller capacity is therefore 5,000 kW (1,450 tons)

Ideal Design Conditions

Lost Chiller Capacity Due to Poor ΔT

5°C (41°F)

9°C (48.25°F)

5°C (41°F)

13°C (55.5°F)

75 L/sec (1,200 gpm)

150 L/sec (2,400 gpm)

75 L/sec (1,200 gpm)

150 L/sec (2,400 gpm)

Chiller sees a ΔT of 4°C (7.25°F) at a flow of 150 L/sec (2,400 gpm)

The chiller capacity is therefore 2,500 kW (725 tons)

Case 1: Mixing Through Decoupler Line

75 L/sec (1,200 gpm)

at5°C (41°F)

Lost Chiller Capacity Due to Poor ΔT

5°C (41°F)

No Flow Through Decoupler

5°C (41°F)

150 L/sec (2,400 gpm)

150 L/sec (2,400 gpm)

150 L/sec (2,400 gpm)

150 L/sec (2,400 gpm)

Case 2: Poor Building Return Temperature

Chiller sees a ΔT of 4°C (7.25°F) at a flow of 150 L/sec (2,400 gpm)

The chiller capacity is therefore 2,500 kW (725 tons)

9°C (48.25°F) 9°C (48.25°F)

Small Loss in ΔT Rapidly ReducesChiller Capacity

System ΔT Chiller Capacity

8.0°C (14.4°F) 100%

7.5°C (13.5°F) 94%

7.0°C (12.6°F) 88%

6.5°C (11.7°F) 81%

6.0°C (10.8°F) 75%

5.5°C (9.9°F) 69%

5.0°C (9.0°F) 63%

4.5°C (8.1°F) 56%

4.0°C (7.2°F) 50%

Assuming a design ΔT of 8°C (14.4°F):

Technical Paper by Erwin Hanson(Pioneer in Chilled Water System Design)

8°C

9°C

11°C

Billing Algorithm for Buildings to Give Incentive to Owners to Improve ΔT

• Adjusted Demand Cost

• Adjusted Consumption Cost

• Total Cost = Demand + Consumption

Total Site Demand Cost

XBldg ton-hrsTotal ton-hrs

XCost

Penalty Factor

Total Site Electric Cost -

Total Adjusted Bldg Demand

CostX

Bldg ton-hrsTotal ton-hrs

The Design of the Human Body

Heart (Variable Volume Primary Pump)

Lungs(Chillers)

Brain (Building End-Users)

History of Variable Primary Flow Projects

• King Saud University - Riyadh (1977)• Louisville Medical Center (1984)• Yale University(1988)• Harvard University (1990)• MIT(1993)• Amgen (2001)• New York-Presbyterian Hospital (2002)• Pennsylvania State Capitol Complex (2005)• Duke University (2006)• NYU Medical Center (2007)• Memorial Sloan-Kettering Cancer Center (2007)

King Saud University – Riyadh (1977)• 60,000 ton capacity with 30,000 tons for first phase• Six 5,000 ton Carrier DA chillers• Seven 10,000 GPM 240 TDH constant speed pumps• Major Problem: Too much head on chilled water pumps• Lesson Learned: Be realistic in predicting growth

Louisville Medical Center (1984)

• Existing system (1984) – Primary/Secondary/Tertiary with 13,000 ton capacity

• Current System (2007)– 120 feet TDH constant speed primary pumps with

building booster pumps – 30,000 ton capacity– Changed the heads on some of the evaporator shells

to change number of passes– Primary pumps are turned OFF during winter, Early

Spring and Late Fall. Building booster pumps are operated to maintain flow.

Yale University (1988)• Existing system (1988)

– Primary/Secondary/Tertiary with 10,500 ton capacity• Current System (2007)

– 180 feet TDH VFD / Steam Turbine driven variable flow primary pumps – 25,000 ton capacity

– Changed the heads on some of the evaporator shells to change number of passes

Amgen (2001)• Creation of a computerized hydraulic model of the existing

chilled water plant and distribution system• Identification of bottlenecks in system flow• Evaluation of existing capacity for present and future loads• Two plants interconnected: Single plant operation for most

of the year, second plant used for peaking• Annual Energy Cost Savings: $500,000

Additional Variable Primary Flow Projects

• Harvard University (1990)• MIT(1993)• New York-Presbyterian Hospital (2002)• Pennsylvania State Capitol Complex (2005)• Duke University (2006)• NYU Medical Center (2007)• Memorial Sloan-Kettering Cancer Center (2007)

• CCWP-1 plant was built four years ago

• CCWP-2 design was 90% complete (Primary/Secondary pumping)

• We were retained by Duke to peer review the design

• Peer review was time sensitive

• Plant design for CCWP-2 was modified to Variable Primary pumping based on our recommendations

Duke University Background

Duke CCWP-1 Before

Duke CCWP-1 After• Dark blue pipe replaces old primary pumps

Duke CIEMAS Building CHW System

90% closed Triple duty valves50% closed

Balancing valve50% closed

Duke CIEMAS Building AHU-9

NYU Medical Center (2007)• Plant survey and hydraulic model indicated unnecessary pumps

• 1,300 horsepower of pumps are being removed, including 11 pumps in two brand new chiller plants

• $300,000 implementation cost

• $460,000 annual energy savings

NYU Medical Center (2007)• Plant survey and hydraulic model indicated unnecessary pumps

• 1,300 horsepower of pumps are being removed, including 11 pumps in two brand new chiller plants

• $300,000 implementation cost

• $460,000 annual energy savings

3 Pumps Removed

7 Pumps Removed

8 Pumps Removed

3 Pumps Removed

Memorial Sloan-Kettering - Before

Memorial Sloan-Kettering - After

Bypass or removal of pumps

Bypass or removal of pumps

Bypass or removal of pump

Pump Cemetery

To date we have removed several hundred large pumps from our clients’ chilled water systems

Plant Capacity Analysis -Detailed System Analysis is a Necessity

Modern computer software allows more complex modeling of system loads, which has proven to be very valuable to optimize performance and minimize cost.

Return on investment to the client for detailed analysis is typically very high.

• Applied revolutionary control logic

New York Presbyterian Hospital

Log Data ~ 20F T

Bristol-Myers Squibb• Biochemistry research building

• 140,000 square feet• AHU-1 (applied new control logic)

• 100,000CFM

• AHU-2 (existing control logic remained)• 100,000 CFM

Bristol-Myers Squibb• Applied revolutionary control logic

PA State Capitol Complex – CHW ΔT

South Nassau Hospital – CHW ΔT

Good Engineers Always Ask “Why?”

• Why does the industry keep installing Primary/Secondary systems?

• Why don’t we get the desired system ΔT?

• Why does the industry allow mixing of supply and return water?

Good Engineers Always Ask “Why?”

• Why does the industry keep installing Primary/Secondary systems?

• Why don’t we get the desired system ΔT?

• Why does the industry allow mixing of supply and return water?

Answer: To keep consultants like us busy!

Why change?

Reasons to Change

• The technology has changed

• Chiller manufacturing industry supports the concepts of Variable Primary Flow

• Evaporator flow can vary over a large range

• Precise controls provides high Delta T

Change is Starting Around the World• Most of the large district cooling plants in Dubai currently use

Primary/Secondary pumping

• By educating the client we were able to convince them that this is not necessary

• We are now currently designing three 40,000 ton chiller plants in Abu Dhabi using Variable Primary Flow as part of a $6.9 billion development project

Summary• There are many chilled water plants with significant

opportunities for improvement• WM Group has a proven record of providing smart solutions

that work• We will be happy to review your plant logs with no obligation

Louisville Medical Center Chilled Water Operating Data

0

5

10

15

20

25

30

35

40

45

50

1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002

Year

CH

W P

rodu

ctio

n(m

illio

n to

n-ho

urs)

0.050

0.075

0.100

0.125

0.150

0.175

0.200

Cos

t($

/ton-

hour

)

Production Cost

1985: $ 0.171/ton-hr

2002: $0.096/ton-hr

Thank You

Hemant Mehta, P.E.

President

WMGroup Engineers, P.C.(646) 827-6400

hmehta@wmgroupeng.com

September 16, 2008

The New Royal ProjectCentral Energy Plant Study

By

Determine the Optimum Central Energy Plant Configuration and Cogeneration Feasibility

Project Objective

• A new tertiary hospital for the region

• 95,000 m2 initial area (basis of analysis)

• Disaster Recovery Consideration• N+1• Onsite Power Generation (+/- 70% of peak demand)• Two separate central plants

The New Royal Project

Project Site

Typical Utility Tunnel

• Developing load profiles for Heating, Cooling and Power

• Developing and screening of Options

• Creating a computer model for energy cost estimate

• Performing Lifecycle Cost Analysis

• Performing Sensitivity Analysis

• Conclusions

Study Approach

• Cooling/Heating – Daily peaks provided by Bassett

• Cooling: 7,400 kWt (2,100 RT)• Heating: 8,000 kWt

• Power – Daily peaks provided by Bassett

• Peak demand: 4,500 kWe• Min. demand: 1,400 kWe

Load Profiles

Cooling Loads

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

Jan

Feb

Mar Ap

r

May Jun Jul

Aug

Sep

Oct

Nov Dec

Cool

ing

Load

(kW

t)Daily Peak Cooling Loads (Provided by Bassett)

Daily Cooling Load Profile1

2:0

0 A

M

1:0

0 A

M

2:0

0 A

M

3:0

0 A

M

4:0

0 A

M

5:0

0 A

M

6:0

0 A

M

7:0

0 A

M

8:0

0 A

M

9:0

0 A

M

10

:00

AM

11:0

0 A

M

12

:00

PM

1:0

0 P

M

2:0

0 P

M

3:0

0 P

M

4:0

0 P

M

5:0

0 P

M

6:0

0 P

M

7:0

0 P

M

8:0

0 P

M

9:0

0 P

M

10

:00

PM

11:0

0 P

M

NRP Average Daily Cooling Load Profile

Max Daily Cooling Load

Min Daily Cooling Load

3-D Cooling Load Profile

Cooling Load Duration Curve

0

500

1,000

1,500

2,000

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

5,000

5,500

6,000

6,500

7,000

7,500

8,000

0

50

0

1,0

00

1,5

00

2,0

00

2,5

00

3,0

00

3,5

00

4,0

00

4,5

00

5,0

00

5,5

00

6,0

00

6,5

00

7,0

00

7,5

00

8,0

00

8,5

00

Lo

ad (T

on

s)

Lo

ad (k

Wt)

Hours

NRP Cooling Load Duration Curve (kWt)

607 Equivalent Full-Load Hours

Heating Loads

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

9,000

Jan

Feb

Mar Ap

r

May Jun Jul

Aug

Sep

Oct

Nov Dec

Hea

ting

Load

(kW

t)Daily Peak Heating Loads (Provided by Bassett)

Daily Heating Load Profile1

2:0

0 A

M

1:0

0 A

M

2:0

0 A

M

3:0

0 A

M

4:0

0 A

M

5:0

0 A

M

6:0

0 A

M

7:0

0 A

M

8:0

0 A

M

9:0

0 A

M

10

:00

AM

11:0

0 A

M

12

:00

PM

1:0

0 P

M

2:0

0 P

M

3:0

0 P

M

4:0

0 P

M

5:0

0 P

M

6:0

0 P

M

7:0

0 P

M

8:0

0 P

M

9:0

0 P

M

10

:00

PM

11:0

0 P

M

NRP Average Daily Heating Load Profile

Max Daily Heating Load

Min Daily Heating Load

3-D Heating Load Profile

Heating Load Duration Curve

0

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

18,000

20,000

22,000

24,000

26,000

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

5,000

5,500

6,000

6,500

7,000

7,500

8,000

0

50

0

1,0

00

1,5

00

2,0

00

2,5

00

3,0

00

3,5

00

4,0

00

4,5

00

5,0

00

5,5

00

6,0

00

6,5

00

7,0

00

7,5

00

8,0

00

8,5

00

Lo

ad (M

BH

)

Lo

ad (k

Wt)

Hours

NRP Heating Load Duration Curve (kWt)

1,742 Equivalent Full-Load Hours

Electric Loads

0

500

1,000

1,500

2,000

2,500

3,000

3,500

4,000

4,500

5,000

Jan

Feb

Mar Ap

r

May Jun Jul

Aug

Sep

Oct

Nov Dec

Elec

tric

Loa

d (k

We)

Daily Peak Electric Loads (Provided by Bassett)

Daily Electrical Load Profile1

2:0

0 A

M

1:0

0 A

M

2:0

0 A

M

3:0

0 A

M

4:0

0 A

M

5:0

0 A

M

6:0

0 A

M

7:0

0 A

M

8:0

0 A

M

9:0

0 A

M

10

:00

AM

11:0

0 A

M

12

:00

PM

1:0

0 P

M

2:0

0 P

M

3:0

0 P

M

4:0

0 P

M

5:0

0 P

M

6:0

0 P

M

7:0

0 P

M

8:0

0 P

M

9:0

0 P

M

10

:00

PM

11:0

0 P

M

NRP Average Daily Electrical Load ProfileMax Daily

Electrical Load

Min Daily Electrical Load

3-D Electrical Load Profile

• Natural Gas: $9.00 / GJ

• Electricity (taken from hospital bill):• Demand Charge: $0.265641 per kVA per day

• Based on contracted annual demand• About $10.00 per kW per month

• Energy Charge:

• $0.14618 / kWh (on-peak, 7 am to 10 pm)• $0.05322 / kWh (off-peak, 10 pm to 7 am and

weekends)

• Fixed Charges: $27.7155 per day• About $830 per month

Utility Rates

• Minimum first cost

• Two locations

• Conventional equipment• Electric chillers

• Gas-fired boilers

• Diesel emergency generators

• No cogeneration or thermal storage

• Operational efficiency and reliability

Base Option Considerations

Central Energy Plant – Base Option

Plant Component

East CEP West CEP

Chiller Plant(2) 2,500 kWt electric motor driven, water-cooled chillers

(2) 2,500 kWt electric motor driven, water-cooled chillers

Boiler Plant(2) 2,750 kWt fire tube boilers producing hot water

(2) 2,750 kWt fire tube boilers producing hot water

Thermal Storage

None None

Power Generation

(1) 2,000 kVA diesel generator (emergency power)

(1) 2,000 kVA diesel generator (emergency power)

• Non-Electric Chillers• Absorption Chillers (with or without heaters)

• Steam Turbine Driven Chillers

• Gas Engine Driven Chillers

• Thermal Storage• Ice Storage

• Chilled Water Storage

• Cogeneration

• Geothermal

Alternative Plant Considerations

Electric vs. Non-Electric Chillers Sample taken from another project

Hybrid Plant – Option 1A Plant

ComponentEast CEP West CEP

Chiller Plant

(1) 2,650 kWt electric motor driven, water-cooled chiller(1) 2,450 kWt direct-fired absorption chiller/heater

(1) 2,650 kWt electric motor driven, water-cooled chiller(1) 2,450 kWt direct-fired absorption chiller/heater

Boiler Plant

(2) 1,750 kWt fire tube boilers producing hot water

(1) 1,500 kWt direct-fired absorption chiller/heater (same unit as above)

(2) 1,750 kWt fire tube boilers producing hot water

(1) 1,500 kWt direct-fired absorption chiller/heater (same unit as above)

Thermal Storage

None None

Power Generation

(1) 2,000 kVA diesel generator (emergency power)

(1) 2,000 kVA diesel generator (emergency power)

• Advantages of ice storage• Ice storage requires less space

• Suitable for low temperature operation

• Disadvantages of ice storage• Ice generation requires more energy

• Ice storage system has a higher first cost

• Ice storage is not considered for this project

Ice Storage vs. Chilled Water Storage

Thermal Storage – Option 2

Plant Component

East CEP West CEP

Chiller Plant(2) 1,750 kWt electric motor driven, water-cooled chillers

(2) 1,750 kWt electric motor driven, water-cooled chillers

Boiler Plant(2) 2,750 kWt fire tube boilers producing hot water

(2) 2,750 kWt fire tube boilers producing hot water

Thermal Storage

(1) 30,000 kWt-hr chilled water storage tank connected to site chilled water distribution system

Power Generation

(1) 2,000 kVA diesel generator (emergency power)

(1) 2,000 kVA diesel generator (emergency power)

Cogeneration AlternativesSystem Application Assessment

Reciprocating Engines Suitable for high electric but low thermal loads such as NRP.

Fuel Cells Emerging technology not for commercial use.

Microturbines Limited capacity of units and requires skilled labor.

High Pressure Steam Boiler and Back Pressure Turbine

No steam required by NRP.

High Pressure Steam Boiler and Condensing Turbine

No steam required by NRP.

Gas Turbine with HRSGTypically for larger installations, requires skilled operators, and possible emissions treatment issues.

Combined Cycle GenerationTypically for larger installations, requires skilled operators, and possible emissions treatment issues.

Engine Generator Topping Cycle

Option 3 – Cogen w/ Gas Engines

Plant Component

East CEP West CEP

Chiller Plant

(2) 1,750 kWt electric motor driven, water-cooled chillers(1) 1,140 kWt hot water-fired absorption chiller

(2) 1,750 kWt electric motor driven, water-cooled chillers(1) 1,140 kWt hot water-fired absorption chiller

Boiler Plant(2) 1,750 kWt fire tube boilers producing hot water

(2) 1,750 kWt fire tube boilers producing hot water

Thermal Storage

None None

Power Generation

(1) 2,000 kVA natural gas generator (cogeneration)

(1) 2,000 kVA diesel generator (emergency power)

(1) 2,000 kVA natural gas generator (cogeneration)

(1) 2,000 kVA diesel generator (emergency power)

* Diesel generators not required if onsite LNG storage is provided

Option 4 – Cogen & Thermal Storage

Plant Component

East CEP West CEP

Chiller Plant

(2) 1,750 kWt electric motor driven, water-cooled chillers(1) 1,140 kWt hot water-fired absorption chiller

(2) 1,750 kWt electric motor driven, water-cooled chillers(1) 1,140 kWt hot water-fired absorption chiller

Boiler Plant(2) 1,750 kWt fire tube boilers producing hot water

(2) 1,750 kWt fire tube boilers producing hot water

Thermal Storage

(1) 10,000 kWt-hr chilled water storage tank connected to site chilled water distribution system

Power Generation

(1) 2,000 kVA natural gas generator (cogeneration)

(1) 2,000 kVA diesel generator (emergency power)

(1) 2,000 kVA natural gas generator (cogeneration)

(1) 2,000 kVA diesel generator (emergency power)

* Diesel generators not required if onsite LNG storage is provided

Summary of OptionsOption Chiller Plant Boiler Plant Thermal Storage

Power Generation

1 (4) 2,500 kWt electric (4) 2,750 kWt boilers None(2) 2,000 kVA diesel backup generators

1A(2) 2,650 kWt electric,

(2) 2,450 kWt absorbers

(4) 1,750 kWt boilers, (2) 1,500 kWt absorbers

None(2) 2,000 kVA diesel backup generators

2 (4) 1,750 kWt electric (4) 2,750 kWt boilers(1) 30,000 kWt-hr chilled water storage

(2) 2,000 kVA diesel backup generators

3(4) 1,750 kWt electric,

(2) 1,140 kWt absorbers(4) 1,750 kWt boilers None

(2) 2,000 kVA natural gas cogen units,

(2) 2,000 kVA diesel backup generators

4(4) 1,750 kWt electric,

(2) 1,140 kWt absorbers(4) 1,750 kWt boilers

(1) 10,000 kWt-hr chilled water storage

(2) 2,000 kVA natural gas cogen units,

(2) 2,000 kVA diesel backup generators

• Simulation of plant operation

• Calculation of total energy use (power and fuel) and cost

Energy Model

Hourly Computer Model

Detailed Equipment Data

Monthly Energy Cost Summary

Monthly Energy Cost Graphs

Comparison of Annual Energy Costs

$3.7 M $3.7 M $3.6 M

$0.9 M $0.8 M

$0.6 M $0.6 M $0.6 M

$2.1 M $2.1 M

$0.0 M

$1.0 M

$2.0 M

$3.0 M

$4.0 M

$5.0 M

Option 1 Option 1A Option 2 Option 3 Option 4

Comparison of Annual Energy Costs

Electric Cost Gas Cost

$4.3 M $4.3 M $4.2 M

$3.0 M $3.0 M

Thermal Storage Economics

• Installed Cost (Opt. 1A):$1,700,000

• Annual Energy Savings: $98,000

• Simple Payback: 17 years

Low cooling load reduces benefits of thermal storage

25-Year Lifecycle Cost Analysis

• Capital Cost

• Energy Cost (gas and electric)

• Maintenance and Consumables Cost

• Staffing Cost

• Economic Rates

• Discount Rate

Construction Cost Estimates

Project Cost FactorsBased on typical healthcare development projects

• Preliminaries and Margin: 23%

• Project Contingency: 15%

• Cost Escalation to Start Date: 15%

• Consultant Fees: 10%

Total multiplier is approximately 1.8

Comparison of Initial Costs

$20.8 M$22.9 M $23.6 M

$28.0 M$29.5 M

$4.2 M$4.2 M

$ M

$5 M

$10 M

$15 M

$20 M

$25 M

$30 M

$35 M

$40 M

Option 1 Option 1A Option 2 Option 3 Option 4

Comparison of Initial Costs

Incremental Cost for Diesel Generators

Maintenance and Staffing Costs

Option Annual Maintenance Cost Annual Staffing Cost

1 $84,000 $130,000

1A $90,000 $130,000

2 $86,000 $130,000

3 $105,000 $195,000

4 $107,000 $195,000

• Options 3 and 4 also require a $240,000 engine overhaul every 5 years (included in analysis)

• Staffing cost based on $65,000 per year for each full-time staff employee

Economic ParametersBased on estimated government rates

• Discount Rate: 8.00%

• Gas Cost Escalation Rate: 4.30%

• Electric Cost Escalation Rate: 3.40%

• Maintenance Escalation Rate: 4.00%

• Consumables Escalation Rate: 4.00%

25-Year Lifecycle Cost Analysis

Cost SummaryOption First Cost

Annual Energy Cost

25-Year Present Worth Cost

1 $20,839,000 $4,345,000 $87,223,000

1A $22,879,000 $4,311,000 $88,825,000

2 $23,558,000 $4,243,000 $88,473,000

3 $32,176,000 $2,988,000 $83,303,000

4 $33,704,000 $2,978,000 $84,722,000

Results of Lifecycle Cost Analysis

$87 M

$89 M$88 M

$83 M

$85 M

$80 M

$81 M

$82 M

$83 M

$84 M

$85 M

$86 M

$87 M

$88 M

$89 M

$90 M

Option 1 Option 1A Option 2 Option 3 Option 4

Comparison of Present Worth Costs

Sensitivity Analysis

• Varying electric demand charge

• Varying gas cost

• Change economic parameters

• Carbon emission tax

• Use of geothermal energy

Thank You

Hemant Mehta, P.E.

President

WMGroup Engineers, P.C.(646) 827-6400

hmehta@wmgroupeng.com