The Cost of Using 1970s EraDesign Concepts and FEARin Chilled Water SystemsWMGroup Engineers, P.C.Presented By: Hemant Mehta, P.E.

What is the FEARNo change in design as previous design had no complains from clientNo complain because no bench mark existsFear to take the first step to change the concepts to use state of the art technologyConsultants sell time. Fear is any new concept will take lots of time and it is not worth the effort

What are1970s EraDesign Concepts?System Design for Peak load onlyPrimary/Secondary/Tertiary Pumping5C (42F) supply temperatureSystem BalancingCircuit SettersBand Aid solution for any ProblemProjected Demand way above realityOversized chiller, pumps TDH and everything else to cover behind

State of the Art Plant conceptsPlant designed for optimum operation for the year. Peak hours are less than 200 hours a yearVariable flow primary pumping system 3.3C (38F) or lower supply temperatureNo System Balancing. Balancing is for a static system.No Delta P valves No Circuit SettersNo Band Aid solution for any ProblemUse chilled water system diversity (0.63) to Project Cooling DemandThe 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:

The Design of the Human BodyHeart (Variable Volume Primary Pump)Lungs (Chillers)Brain (Building End-Users)

Basic 1970s Era Chiller Plant DesignPrimary PumpSecondary PumpDecoupler LineBuilding LoadsChiller

Current Design Used on Many Large District Chilled Water SystemsPrimary PumpSecondary PumpDecoupler LineBuilding LoadsChillerEnergyTransferStationBuilding Pump

Modern Variable Volume Primary Chiller Plant DesignBuilding LoadsChillerVariable Speed Primary Pump

Lost Chiller Capacity Due to Poor T5C (41F)No Flow Through Decoupler13C (55.5F)5C (41F)13C (55.5F)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 T of 8C (14.5F) 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 T5C (41F)9C (48.25F)5C (41F)13C (55.5F)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 T of 4C (7.25F) 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 Line75 L/sec (1,200 gpm)at5C (41F)

Lost Chiller Capacity Due to Poor T5C (41F)No Flow Through Decoupler5C (41F)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 TemperatureChiller sees a T of 4C (7.25F) at a flow of 150 L/sec (2,400 gpm)

The chiller capacity is therefore 2,500 kW (725 tons) 9C (48.25F)9C (48.25F)

Small Loss in T Rapidly ReducesChiller CapacityAssuming a design T of 8C (14.4F):

System TChiller Capacity8.0C (14.4F)100%7.5C (13.5F)94%7.0C (12.6F)88%6.5C (11.7F)81%6.0C (10.8F)75%5.5C (9.9F)69%5.0C (9.0F)63%4.5C (8.1F)56%4.0C (7.2F)50%

Technical Paper by Erwin Hanson(Pioneer in Chilled Water System Design)8C9C11C

Billing Algorithm for Buildings to Give Incentive to Owners to Improve TAdjusted Demand Cost

Adjusted Consumption Cost

Total Cost = Demand + Consumption

Total Site Demand CostXBldg ton-hrsTotal ton-hrsXCost Penalty Factor

Total Site Electric Cost-Total Adjusted Bldg Demand CostXBldg ton-hrsTotal ton-hrs

The Design of the Human BodyHeart (Variable Volume Primary Pump)Lungs (Chillers)Brain (Building End-Users)

History of Variable Primary Flow ProjectsKing 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 phaseSix 5,000 ton Carrier DA chillersSeven 10,000 GPM 240 TDH constant speed pumpsMajor Problem: Too much head on chilled water pumpsLesson Learned: Be realistic in predicting growth

Louisville Medical Center (1984)Existing system (1984) Primary/Secondary/Tertiary with 13,000 ton capacityCurrent System (2007)120 feet TDH constant speed primary pumps with building booster pumps 30,000 ton capacityChanged the heads on some of the evaporator shells to change number of passesPrimary 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 capacityCurrent System (2007)180 feet TDH VFD / Steam Turbine driven variable flow primary pumps 25,000 ton capacityChanged 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 systemIdentification of bottlenecks in system flowEvaluation of existing capacity for present and future loadsTwo plants interconnected: Single plant operation for most of the year, second plant used for peakingAnnual Energy Cost Savings: $500,000

Additional Variable Primary Flow ProjectsHarvard 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 agoCCWP-2 design was 90% complete (Primary/Secondary pumping)We were retained by Duke to peer review the designPeer review was time sensitivePlant design for CCWP-2 was modified to Variable Primary pumping based on our recommendationsDuke University Background

Duke CCWP-1 Before

Duke CCWP-1 AfterDark blue pipe replaces old primary pumps

Duke CIEMAS Building CHW System90% closedTriple duty valves50% closed

Balancing valve50% closedDuke CIEMAS Building AHU-9

NYU Medical Center (2007)Plant survey and hydraulic model indicated unnecessary pumps1,300 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 pumps1,300 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 Removed7 Pumps Removed8 Pumps Removed3 Pumps Removed

Memorial Sloan-Kettering - Before

Memorial Sloan-Kettering - After Bypass or removal of pumpsBypass or removal of pump

Pump CemeteryTo date we have removed several hundred large pumps from our clients chilled water systems

Plant Capacity Analysis -Detailed System Analysis is a NecessityModern 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 logicNew York Presbyterian HospitalLog Data

Bristol-Myers SquibbBiochemistry research building140,000 square feetAHU-1 (applied new control logic)100,000CFMAHU-2 (existing control logic remained)100,000 CFM

Bristol-Myers SquibbApplied revolutionary control logic

PA State Capitol Complex CHW T

South Nassau Hospital CHW T

Good Engineers Always Ask Why?Why does the industry keep installing Primary/Secondary systems?Why dont we get the desired system T?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 dont we get the desired system T?Why does the industry allow mixing of supply and return water?

Answer: To keep consultants like us busy!

Why change?

Reasons to ChangeThe technology has changedChiller manufacturing industry supports the concepts of Variable Primary FlowEvaporator flow can vary over a large rangePrecise controls provides high Delta T

Change is Starting Around the WorldMost of the large district cooling plants in Dubai currently use Primary/Secondary pumpingBy educating the client we were able to convince them that this is not necessaryWe 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

SummaryThere are many chilled water plants with significant opportunities for improvementWM Group has a proven record of providing smart solutions that workWe will be happy to review your plant logs with no obligation

Thank You

Hemant Mehta, P.E.President

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

hmehta@wmgroupeng.com

September 16, 2008The New Royal Project

Central Energy Plant Study

By

Determine the Optimum Central Energy Plant Configuration and Cogeneration FeasibilityProject Objective

A new tertiary hospital for the region95,000 m2 initial area (basis of analysis)Disaster Recovery ConsiderationN+1Onsite Power Generation (+/- 70% of peak demand)Two separate central plantsThe New Royal Project

Project Site

Typical Utility Tunnel

Developing load profiles for Heating, Cooling and PowerDeveloping and screening of OptionsCreating a computer model for energy cost estimatePerforming Lifecycle Cost AnalysisPerforming Sensitivity AnalysisConclusions

Study Approach

Cooling/Heating Daily peaks provided by Bassett

Cooling:7,400 kWt (2,100 RT)Heating:8,000 kWtPower Daily peaks provided by Bassett

Peak demand: 4,500 kWeMin. demand:1,400 kWeLoad Profiles

Cooling Loads

Daily Cooling Load Profile

3-D Cooling Load Profile

Cooling Load Duration Curve607 Equivalent Full-Load Hours

Heating Loads

Daily Heating Load Profile

3-D Heating Load Profile

Heating Load Duration Curve1,742 Equivalent Full-Load Hours

Electric Loads

Daily Electrical Load Profile

3-D Electrical Load Profile

Natural Gas:$9.00 / GJElectricity (taken from hospital bill):Demand Charge: $0.265641 per kVA per dayBased on contracted annual demandAbout $10.00 per kW per monthEnergy 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 dayAbout $830 per monthUtility Rates

Minimum first costTwo locationsConventional equipmentElectric chillersGas-fired boilersDiesel emergency generatorsNo cogeneration or thermal storageOperational efficiency and reliability

Base Option Considerations

Central Energy Plant Base Option

Plant ComponentEast CEPWest CEPChiller Plant(2) 2,500 kWt electric motor driven, water-cooled chillers(2) 2,500 kWt electric motor driven, water-cooled chillersBoiler Plant(2) 2,750 kWt fire tube boilers producing hot water(2) 2,750 kWt fire tube boilers producing hot waterThermal StorageNoneNonePower Generation(1) 2,000 kVA diesel generator (emergency power)(1) 2,000 kVA diesel generator (emergency power)

Non-Electric ChillersAbsorption Chillers (with or without heaters)Steam Turbine Driven ChillersGas Engine Driven ChillersThermal StorageIce StorageChilled Water StorageCogenerationGeothermal

Alternative Plant Considerations

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

Hybrid Plant Option 1A

Plant ComponentEast CEPWest CEPChiller 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/heaterBoiler 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 StorageNoneNonePower Generation(1) 2,000 kVA diesel generator (emergency power)(1) 2,000 kVA diesel generator (emergency power)

Advantages of ice storageIce storage requires less spaceSuitable for low temperature operationDisadvantages of ice storageIce generation requires more energyIce storage system has a higher first costIce storage is not considered for this project

Ice Storage vs. Chilled Water Storage

Thermal Storage Option 2

Plant ComponentEast CEPWest CEPChiller Plant(2) 1,750 kWt electric motor driven, water-cooled chillers(2) 1,750 kWt electric motor driven, water-cooled chillersBoiler Plant(2) 2,750 kWt fire tube boilers producing hot water(2) 2,750 kWt fire tube boilers producing hot waterThermal Storage(1) 30,000 kWt-hr chilled water storage tank connected to site chilled water distribution systemPower Generation(1) 2,000 kVA diesel generator (emergency power)(1) 2,000 kVA diesel generator (emergency power)

Cogeneration Alternatives

SystemApplication AssessmentReciprocating EnginesSuitable for high electric but low thermal loads such as NRP.Fuel CellsEmerging technology not for commercial use. MicroturbinesLimited capacity of units and requires skilled labor. High Pressure Steam Boiler and Back Pressure TurbineNo steam required by NRP.High Pressure Steam Boiler and Condensing TurbineNo 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 * Diesel generators not required if onsite LNG storage is provided

Plant ComponentEast CEPWest CEPChiller 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 chillerBoiler Plant(2) 1,750 kWt fire tube boilers producing hot water(2) 1,750 kWt fire tube boilers producing hot waterThermal StorageNoneNonePower 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)

Option 4 Cogen & Thermal Storage * Diesel generators not required if onsite LNG storage is provided

Plant ComponentEast CEPWest CEPChiller 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 chillerBoiler Plant(2) 1,750 kWt fire tube boilers producing hot water(2) 1,750 kWt fire tube boilers producing hot waterThermal Storage(1) 10,000 kWt-hr chilled water storage tank connected to site chilled water distribution systemPower 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)

Summary of Options

OptionChiller PlantBoiler PlantThermal StoragePower Generation1(4) 2,500 kWt electric(4) 2,750 kWt boilersNone(2) 2,000 kVA diesel backup generators1A(2) 2,650 kWt electric,(2) 2,450 kWt absorbers(4) 1,750 kWt boilers, (2) 1,500 kWt absorbersNone(2) 2,000 kVA diesel backup generators2(4) 1,750 kWt electric(4) 2,750 kWt boilers(1) 30,000 kWt-hr chilled water storage(2) 2,000 kVA diesel backup generators3(4) 1,750 kWt electric,(2) 1,140 kWt absorbers(4) 1,750 kWt boilersNone(2) 2,000 kVA natural gas cogen units,(2) 2,000 kVA diesel backup generators4(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 operationCalculation of total energy use (power and fuel) and costEnergy Model

Hourly Computer Model

Detailed Equipment Data

Monthly Energy Cost Summary

Monthly Energy Cost Graphs

Comparison of Annual Energy Costs$4.3 M$4.3 M$4.2 M$3.0 M$3.0 M

Thermal Storage EconomicsInstalled Cost (Opt. 1A):$1,700,000Annual Energy Savings: $98,000Simple Payback: 17 years

Low cooling load reduces benefits of thermal storage

25-Year Lifecycle Cost AnalysisCapital CostEnergy Cost (gas and electric)Maintenance and Consumables CostStaffing CostEconomic RatesDiscount 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

Maintenance and Staffing CostsOptions 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

OptionAnnual Maintenance CostAnnual Staffing Cost1$84,000$130,0001A$90,000$130,0002$86,000$130,0003$105,000$195,0004$107,000$195,000

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 Summary

OptionFirst CostAnnual Energy Cost25-Year Present Worth Cost1$20,839,000$4,345,000$87,223,0001A$22,879,000$4,311,000$88,825,0002$23,558,000$4,243,000$88,473,0003$32,176,000$2,988,000$83,303,0004$33,704,000$2,978,000$84,722,000

Results of Lifecycle Cost Analysis

Sensitivity AnalysisVarying electric demand chargeVarying gas costChange economic parameters Carbon emission taxUse of geothermal energy

Thank You

Hemant Mehta, P.E.President

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

hmehta@wmgroupeng.com

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