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3/19/2014 3/19/2014

3/19/2014

APEM Spring Forum

Meeting the Conservative

Challenges of the 21st Century

with

Magnetic Bearing Chillers

History of Magnetic Bearings

Mag Lev Trains Artificial Hearts

Gas Turbines

Introduction to Mag Bearing Chillers Since 2003

• Magnetic bearing chillers minimize efficiency losses and

mechanical complexity inherent to traditional centrifugal

chillers

Typical Performance Comparisons

0

0.2

0.4

0.6

0.8

1

20% 40% 60% 80% 100%

Percent Load

kW

/To

n

Frictionless Centrifugal W/C ScrewW/C Scroll Centf w/VFD

All Chillers at 150 Tons

Frictionless Compressor Benefits

• Efficient HFC-134a Design

– Part load performance as low as .325 kW/ton IPLV at ARI

• Quiet

– As low as 73 dBA per ARI Standard 575

– The pumps are louder than the chiller

• Low Maintenance Costs / Long Term Sustainability

– Eliminates the oil support system

Ideal for green buildings

County Office Building, Olathe KS

150-ton McQuay WMC Chiller installed

LEED Gold certified

6

Magnetic Bearings - How do they work?

• Magnetic Bearings have less than 0.2% the Friction Losses compared to Conventional Roller or Ball Bearing Designs

Why Magnetic Bearings?

Permanent Magnets

Radial Bearings

compressor has permanent magnetic shaft and bearings,

position is “trimmed” with electromagnets.

Radial Bearings

10

• The Rotor Shaft Is Held in Position

With Electro Magnetic Cushions.

These Continually Change in Field

Strength to Keep the Shaft

Centrally Positioned. The Shaft’s

Position Is Monitored by 10 Sensor

Coils Whose Signals Are Fed Back

to a Digital Controller

• LRA = 2 amps

Magnetic Bearing Drive train

How does it work?

• 2-Stage

• Integral VFD – Speeds Up to 35,000 RPM

• Magnets Levitate Shaft and Impeller

• (2) Radial, (1) Axial Thrust

• Direct Drive 97% Efficient Synchronous Motor

• Capacitors Provide Coast Down Protection

First Generation Magnetic Bearing Compressor

Integral VFD

Permanent magnet

brushless DC motor

Shaft & impeller

Inlet Guide

Vanes

Heat exchanger

for motor cooling

(refrigerant cooled

motor/VFD)

Compressor

control module

Magnetic bearings

and sensors

Discharge Port

Suction gas

How Does this Compressor Handle a Power Outage?

• Motor becomes a generator

• Charges bank of capacitors

• After the compressor comes to a complete stop, the rotor de-levitates normally onto touchdown bearings

Second Generation Compressor Design

• Improved IPLV – Increased Unit Efficiency from 75 to 100% Load

• Higher Capacity up to 700 Tons

• High Efficiency Aerodynamics – Single stage, Shrouded Impeller

• Improved Drive train – Stronger, Lighter Magnetic Bearings & Rotor

• Higher Lift Capabilities – CHW Storage

– Higher Latent Load Applications

Second Generation Magnetic Bearing Compressor

Magnetic bearings

and sensors

Permanent magnet

brushless DC motor

(refrigerant-cooled)

Suction gas

Discharge Port

Inlet Guide

Vanes

Single Stage

Impeller

VFD and controls

contained in

external panel

ARI Standard for Part Load Analysis - IPLV

“Integrated Part Load Value”

% Load % Hrs ECWT (°F)

100 1 85

75 42 75

50 45 65

25 12 65

• 44°F LCHWT

Engineered for flexibility and performance |

State of the Art Performance

Capacity

Tons

Full load

kW/ton

IPLV

550 0.551 0.325

500 0.531 0.312

390 0.599 0.328

360 0.572 0.325

290 0.627 0.326

250 0.627 0.354

150 0.616 0.357

Designed to be Quiet

• Ideal for any sound-sensitive application: Education, Healthcare, Multi-

Residential, Offices, Churches, Performance and Conference centers

Tons A-weighted Sound Pressure, db (per AHRI Std 575)

100% Load 75% Load 50% Load 25% Load

150 75.6 72.4 68.7 68.0

250 81.6 78.1 74.9 73.4

290 81.6 78.1 74.9 73.4

390 83.3 82.5 80.8 77.0

500 82.6 76.9 76.1 77.9

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Lowest Total Cost of Ownership

High Reduced Sustainability Lowest Total Costs

Efficiency Maintenance

+ + =

Oil-Free Design

• Compare to normal centrifugal chiller

– NO Oil heater

– NO Oil cooler

– NO Oil pump and starter

– NO Reservoir

– NO Oil relief valves

– NO Oil piping

– NO Oil Filter/Housing/Shutoff Valves

– NO Oil Sensors and controls

• Greater reliability

– “Fewer things to break”

• Reduced maintenance costs

Oil Free = Long Term Sustainability

“The negative effects of oil contamination can

result in added operating costs equal

to your original chiller investment”

Oil Contamination - ASHRAE Project 601

Ran

do

m S

am

ple

s

0 5 10 15 20

13% Avg

% of Oil in Refrigerant

Engineered for flexibility and performance |

Negative Effects of Oil

Data from ASHRAE Research Project 601

Sustainability of Performance

Designed for Maximum Efficiency

Oil management systems degrade chiller performance by clogging nucleate

boiling sights on the surface of the tubes

Evaporator

Tube Surface

First Generation Frictionless Centrifugals

169”

48.2”

94.5”

Second Generation Frictionless Centrifugals

Model - WME500S

Meeting LEED Requirements

• EA Credit 1 – Better Efficiency vs

Baseline Building

Energy Consumption

- 19 Points Available

• EA Credit 4 – Enhanced Refrigerant

Management

- 2 Points Available

Magnetic Bearing Chiller Summary

• Exceptional Part Load Performance

– Reduced operating cost, EAc1 LEED points

• Low Sound Levels

– Application flexibility

• Oil-free Design

– Increased reliability, sustainable performance, reduced maintenance

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Thank You