Thank You ForToday’s Opportunity

Agenda

• Introductions•Chiller Plant Design Criteria•Chiller Plant Configurations•Different Chiller Technologies•Refrigerants•Chiller Plant Optimization Techniques

Introductions• John Calcagno-Formosa Account Manager

– Sales Engineer/Account Manager-Carrier Corporation– BSME Rutgers University – Over 27 Years HVAC Industry Experience

• This presentation applies to typical chiller plants. The type of building or process the plant serves will affect the design.

• Different criteria for different applications.• This presentation will focus on chillers.

Chiller Plant Design

Chiller Plant Design

• Type of application• Process Reliability, durability, life cycle cost • Data Center Reliability, life cycle cost, cold

condenser water.• Health Care Reliability, first cost, efficiency• Higher Education First cost, life cycle cost• Office First cost• District Cooling Reliability, life cycle cost

6

Design Criteria

• Review capacity

7

Design Criteria

Optimizing Chiller Plant Design

Components of Chiller Plant

• Chillers

• Chiller Heat Rejection

• Distribution System

• Load

Piping Configurations

• Variable Primary (Variprime)

Chiller Plant Configurations

• “Keep things as simple as possible but no simpler”

Single Chiller Constant Flow

Single Chiller Constant Flow• Advantages

• Simple• Low first cost

• Disadvantages:• No redundancy• Chiller cannot efficiently match the load• Does not take advantage of varying load• Part load-pumping water not needed

Multiple Chillers Parallel-Constant Flow

Multiple Chillers Parallel-Constant Flow

• Advantages• Redundancy• Can better match capacity at part load

• Disadvantages• Part load- one chiller off – mixing of chilled water supply• Part load- pumping water around that is not needed

Multiple Chillers Parallel-Constant Flow

TempMixing

Multiple Chillers Parallel Part Load Flow Reduction

Shut down one chiller/pump at part LOAD. But what about the flow?

Multiple Chillers Parallel Part Load Flow Reduction

• Advantages• Redundancy• Ability to match load by staging chillers• Saves pump energy at part load

• Disadvantages• Significant reduction of flow at part load• Chiller production loop is hydraulically tied to chiller

consumption loop

Multiple Chillers in Series-Constant Flow

Multiple Chillers In Series-Constant Flow

• Advantages• Eliminates temperature mixing and flow problems• Full flow at all loads• Series/counterflow arrangement-efficiency

• Disadvantages• Flow rate through each chiller is entire system flow-double

the flow for parallel chillers• Pressure drop is additive-bigger pumps and more energy• Part load-pumping water around building not needed• Limited to two chillers

Multiple Chillers In Parallel Primary/Secondary System

Decoupler pipe

Multiple Chillers in Parallel-Primary/Secondary System

• Advantages• Decouples or separates the chilled water production piping

from the chiller water consumption piping• Eliminates temperature mixing and flow reduction • Part load-match chiller capacity to load• Part load-reduced flow

• Disadvantages• More pumps required• Moderately complicated controls required• Water balancing important

Multiple Chillers In Parallel-Variable Primary System

Multiple Chillers In Parellel-Variable Primary System

• Advantages• Eliminates set of pumps• Efficient

• Disadvantages• Must coordinate minimum flow and rate of change with

chiller manufacturer• Moderately complicated controls

Variable Primary FlowPrinciples to follow:• Confirm chiller vendors minimum acceptable flow

rate (may require higher initial design cooler pressure drop)

• Specify flow meters or DP transmitters to measure/ maintain chiller minimum flows

• Design bypass for flow rates below minimum• Find out what rate of change in flow is acceptable

from chiller vendor(s) and put this in sequence of operation

• Provide ton-hr metering to measure machine capacity for sequencing logic (note, 23XRV speed is directly proportional to capacity, so speed can be used to sequence machines)

Variable Primary Flow – Rate of Change

Carrier Other

Model 23XRV Single Centrifugal

Multiple Compressors

Rate of Change (%/min) 70% 30% 10%

Minimum Loop Volume (gal)* 450 900 1,800

Why is this Important?Industry Best!

* = 300 Tons Comfort Cooling Application

In VPF applications, select a machine with high acceptable rate of flow change and specify rate (in %

change/Minute).

Compressor response time in VPF system

If the evaporator flow to the chiller is halved, the load is halved.

If the chiller does not unload quickly enough (VFD, IGV staging), the chilled water temperature will drop and either result in:

1. Recycle (LCWT too far below set point) or 2. Worst Cases, Freeze Trip (LCWT below freeze

protection value) or Surge Trip (at least for a centrifugal compressor).

More Flexibility = Less Nuisance Trips

Summary

• No right configuration for all plants• Must evaluate the design criteria• Take advantage of chiller’s modern

controls

Questions

31

Water Cooled Chiller Technologies

• Centrifugal• Helical Rotary (Screw)• Scroll• Absorption• Direct Fired Absorption

32

Water Cooled Chiller Technologies

• Centrifugal• Helical Rotary (Screw)• Scroll• Absorption• Direct Fired Absorption

Water Cooled Chiller Technologies

Product Portfolio

0 3,000

1,000

250 1,875

100 500 1,500

2,250

SCREW

CENTRIFUGAL

SCROLL

30MP 15-45 Tons

30HX 75-265 Tons

30XW 150-300 Tons Single Circuit 325-400 Tons Dual Circuit

23XRV 275-550 Tons

19XR(V) Single Stage 200-1,600 Tons

WATER-COOLED CHILLERS

23XRV 200-550 Tons

19XR(V)E Two Stage 800-1,600 Tons

19XR6 Two Stage 1,600-2,250 Tons

Q2 - 2014Q2 - 2013

Scroll Compressor

Helical Rotary/Screw Compressor

2 or 3

• Use variable frequency drive to slow down the compressor

Carrier 23XRV – Simple

Simple: 3 moving partsNo surge No purgeNo shaft sealsNo guide vanesNo slide valves No EXV’sNo chlorineNo phase-outNo refrigerant pumpsNo pressurization systemsNo bearing capacitors to changeNo pumps, hoses or clamps for VFDNo glycol cooling required for VFDNo motor heat rejection to the room

Given the choice, aren’t fewer worries better?

Centrifugal Compressor

• Use inlet guide vanes and variable frequency drive for unloading

39

IMPELLER WHEEL

Impeller

40

Shroud

Funnel-type device that ensures that the

refrigerant flows through the compressor.

41

PIPE DIFFUSER

Diffuser

Medium Pressure vs Low Pressure

• Evaporator – water, contaminants are sucked into the chiller

43

• Keeps Air and Contaminants Out• Keeps Refrigerant In• Store Refrigerant Inside Chiller• Equipment Life Extended• Efficiency Losses Avoided• Purge Maintenance Eliminated

Positive Pressure Design

Refrigerants

• HCFC-123 Low pressure refrigerant• Subject to phase out-MAJOR reduction in production NOW

(2015)!

• HFC-134a Medium Pressure Refrigerant• No phase out!

Semi Hermetic Versus Open Drive Design

Semi Hermetic Versus Open Drive Design

• Semi-hermetic: Motor and Compressor are one sealed assembly. Motor is cooled by refrigerant.

• Open Drive: Motor and Compressor are separate assemblies. Compressor has shaft seal to contain refrigerant in compressor.

Replacement of open drive shaft seals costs $3000 to $5000 every 3 to 5 Years.

“Open drive seals lose 2% of total refrigerant charge annually.” ARI Report 11/98

Shaft Seals-Leakage Source

Motor Cooling From Ambient Air

Ventilation vents let contaminants in!(dirt, salt, production debris etc)

Open Drive DesignAirborne dirt and contaminants in

Open Drive design

• Only ONE Major Manufacturer makes an open drive chiller.• If a design is used so that it is easy to repair, shouldn’t this

cause some concern?

Motor HealthOpen Motor Hermetic Motor

Heat – most common cause of premature failure. “Each 10C rise above the rating may reduce the motor lifetime by one half” - NEMA

“Class B Rise” results in 120C (248 F) operating temperature.

Motors can operate cool enough that insulation is applied to prevent sweating.

Dirt – abrasion can cause insulation failure, buildup increases operating temperature

Motor completely exposed to dirt, dust and debris in mechanical room as it actively pulls air through the motor internal vents to cool itself.

Motor completely isolated inside clean, cool refrigerant boundary, unexposed to mechanical room dirt, dust or debris.

Motor HealthOpen Motor Hermetic Motor

Moisture – reduces motor insulation resistance, can cause catastrophic failure.

Open motors must be equipped with internal heaters to prevent condensation.

Condensation on motor windings is not possible – it is sealed in refrigerant circuit.

Vibration – can cause bearing fatigue and failure, or cracks in insulation system and failure.

Compressor and motor balanced separately. Coupling can increase balance issues.

Compressor and motor dynamically balanced together – no coupling.

Mechanical Room Renovation When you need to install equipment, move a pipe , paint

or do some sort of renovation in mechanical room … should you turn your chillers off?

No …Run risk that dirt, dust or debris in air will cause motor failure or shorten

motor life.

Yes …Turn chillers off and

cover motor intakes. Provide temporary

cooling or no cooling at all.

Semi-Hermetic vs. Open Motors

Condensation on motor windings is normal.

Moisture degrades insulation resistance.

Starting a motor with moisture on its winding can cause insulation failure and require a rewind.

To prevent condensation, motor winding heaters are energized any time motors are off.

If power to motor and motor winding heaters is lost, a megger test should be performed to confirm insulation strength before starting.

All of this costs money. Is your customer willing to pay?

User Chiller Load Tons 500

Defined Power Consumption kW/Ton 0.60

Motor Efficiency pts 0.95

Calculated kW 300

hp 402

Motor Loss pts 0.05

hp 20.12

Motor Cooling Load Btu/Hr 51,173

Motor Cooling Load (Tons) 4.3

Competitor Open Motor Drive

• Open motors reject heat to the facility space, which must be tempered (air conditioned) or ventilated to a maximum of 104F indoor ambient to assure design motor and starter life

Carrier Confidential

Motor Heat Rejection

Competitor Open Motor Drive

Open motors require no moisture intrusion at start up. Moisture in windings at start up/after power loss can cause motor failure.

Motor Anti-Condensation Heaters

Megger motor test required $ for insulation checks by technician after idle periods

Strip Winding Heater required to prevent moisture intrusion

$ in motor heater equipment costs$$ yearly heater wattage costs

User Full Load Tons Tons 500IPLV kW/ton 0.34Hours of Operation Hrs 3000

Calculated Annual Mech Room Cooling kW 5,046Annual kW Strip Heaters kW 3,456Total Open Motor Parasitic kW 8,502

Actual IPLV kW/ton 0.350

Water Cooled Oil Cooler

• Requires regular maintenance (scaling/cleaning with acid solution)

• Additional failure modes created– Oil in water (EH&S safety issue)– Water in oil (catastrophic failure)

Additional Costs for Purchasing Open Drive Design

• Maintenance and Operating Costs– Weekly – check the shaft seal

oil bottle– 3-5 Year - Shaft Seal

maintenance cost – Yearly – Motor Air Filter

maintenance cost – As Necessary – Top off

refrigerant charge – As Necessary – Winding

cleaning maintenance cost – As Necessary – Possible

Megger Motor maintenance check

– Yearly - Mechanical Room Cooling operating cost

– Yearly – Strip Heater operating cost

• Efficiency Comparison– 3% for open motor– 4% for harmonic filter– 1-3% refrigerant loss

DID YOU FACTOR AN ADDITIONAL $ IN COSTS FOR YOUR CHILLER

• Additional Unanticipated Costs– Air Conditioner for

Mechanical Room – TEWAC Motor – Harmonic Filter – Storage Tank – Sound Blanket – Motor Heaters

Open Drive vs. Hermetic

• Home refrigerator is a hermetic design

Automobile is an open design

Which design requires more refrigerant to be added?

Advantages of Semi Hermetic Design

Semi-Hermetic Motor• Refrigerant cooled motor keeps

motor heat out of the mechanical room• Saves $ to cool mechanical

room• Minimizes alignment, vibration

and shaft seal maintenance of open motors• Saves $ in maintenance and

shaft seal replacement costs• Refrigerant cooled motors

operate in a clean, cool environment.• Saves $ in motor repair costs

Hermetic Motor vs. Open Drive Motor

Carrier Corporation announces refrigerant warranty for all new centrifugal chillers sold in USA at Engineering Green Building Conference July 20, 2004.

Warranty applicable for all Evergreen centrifugal chillers shipped after October 1, 2004.

Carrier will cover refrigerant leaks above 0.1% for the first five years of operation and for the life of the chiller if the owner has a service contract with Carrier Commercial Service.

R134a Refrigerant Warranty

The Right Technology

Questions

Chiller Part Load Performance

Part load performance can be…• Part load capacity

• 90%, 80%, 70%…

OR• Lower condensing temperature

• Condenser water off the tower (80, 75, 70 degrees…)

• Lower outdoor air temp (90, 85, 80 degrees…)

Full load is defined as 100% load on design day! All other conditions are part load.

What is Part Load?

IPLVOR

NPLV = 0.01 + 0.42 + 0.45 + 0.12 A B C D

1

1% 42% 45% 12%

ECWT 85 75 65 65

WEIGHT %

LOAD 100% 75% 50% 25%

ARI Part Load Weighting Factors

99%

ARI 550-590

Compressor Input kW ~

Mass Flow X Lift

Load

Chiller

CoolingTower

Compressor/Cycle Efficiency

Like pumps, chiller energy consumption is a function of mass flow and differential pressure. KW = Tons x Lift

Chiller Energy

Imagine carrying a backpack of bricks up 55 flights of stairs.

Lift Requires Energy

97 F Saturated Condensing Temperature

55

42 F Saturated Suction Temperature

Refrigerant TemperatureFor refrigerant to condense, it must be warmer than leaving condenser water.

95 F + 2F approach = 97F

To boil, refrigerant must be colder than leaving chilled water. 44F – 2F approach = 42F

95F

44F

85F

54F

Refrigerant temperatures are based on leaving water temperatures! Lift = 97F-42F = 55F

42 F / 40 PSI95F /97 F / 120 PSI

80F /82F

SAT. LIQUID

SAT. VAPOR

Refrigerant Effect(Capacity)

Com

pres

sion

Heat Rejection

Enthalpy

SCT

Reduced Lift

Pre

ssu

re

42

82

97

SST

Lower Lift = Less Work = Lower kW

Pressure Enthalpy Chart-LIFT

Lift = Sat Condensing Temp – Sat Suction TempLift 1 = 97 – 42 = 55 deg FLift 2 = 82 – 42 = 40 deg F BETTER!!

42 F / 40 PSI95F /97 F / 120 PSI

80F /82F / 90 PSI

59F /61F /60 PSI

SAT. LIQUID

SAT. VAPOR

Refrigerant Effect(Capacity)

Com

pres

sion

Heat Rejection

Enthalpy

SCT

Reduced Lift

Pre

ssu

re

42

82

97

SST

Lower Lift = Less Work = Lower kW

Pressure Enthalpy Chart-PRESSURE

60 PSI-40 PSI = 20 PSI. Sufficient differential to provide proper refrigerant flow, oil return, and efficient consistent operation.

How centrifugals change speed

Flow ~ V, ATo increase flow, increase rotor

speed (with fixed flow area)

Lift ~ V2

To increase lift, increase speed

Power ~ Flow x Lift ~ V3

Without LIFT reduction, speed can not reduce

A reduction in LIFT allows a speed reduction.Lift is a function of the speed squared.Power is related to the speed cubed!

V

Diameter

FlowArea

Ideal Fan Laws Dictate the relationship between speed, flow and lift

All centrifugal chillers are subject to Ideal Fan Law – Minimum speed approximately 65%, IGV

for remainder

SAVINGS FROM COLD CONDENSER WATER

• Three 1400 ton Carrier 19XRV variable speed chillers• Data Center• Analyze savings operating chillers with 55 deg F versus 65

deg F and 75 deg F• 0.13 $/kwh simple rate

Net Present Worth Savings from 55 F vs…

ECWT 65F 75F

20 year life cycle $217,550 $468,880

Entering Condenser Water Temperature

570

600

630

643

630

Tons

85oF 75oF 70oF <65oF80oF

550

CarrierCarrier capacity increases as

condenser water temperature decreases

Additional Capacity

Questions

Chiller Heat Recovery

• Instead of rejecting heat to the condenser water loop, why not use this heat?

79

Heat Recovery Benefits

Chillers can transfer heat for as little as 25% of the cost required to create heat with a boiler.

Natural Gas Boiler

($12/1,000 ft3)

Electric Boiler ($0.10/kWh)

Fuel Oil Boiler ($ 3/gal)

10%

20%

30%

40%

50%

60%

70%

80%

50%

71% 75%

30XW Heat Recovery Chiller Savings vs. Boilers

Hot Water SystemsHow can we capture sufficient heat for useful purposes?

Building Heat

Service Hot Water

Process Heat

Why Heat Recovery?ASHRAE 90.1-2004 Heat Recovery for Service Water Heating, Section § 6.5.6.2

• Operates 24 hours a day• Total heat rejection exceeds about 400 tons of chiller

capacity • Service water-heating load exceeds 1,000,000 Btu/h

– 1,000 bed nursing home or 75 room full service hotel

Provide the smaller of:• 60% of the peak heat rejection load at design conditionsor• preheat of the peak service hot water draw to 85°F.

Exceptions:• Minimum 30% recovery from condenser water heat for

space heating or• 60% or more of service water heating from site solar or

cogeneration, condensate subcooling, or solar panels.

Condenser Water Heat RecoveryHEX Captures Condenser Water Heat“Wasted” Heat for Service Hot Water Make-up85°F Make-up Water Caution: Higher LCWT Increases Chiller Lift, Reduces Efficiency

Heat Out

Heat In

Heat Out

83

Confirming Savings

Real World Examplei-Vu® Controls on 30XW Heat Machine at Charlotte

Factory

30XW

Over $100,000 per year in energy savings!!

Questions

Thank You ForToday’s Opportunity