Large Tonnage ChillerWC Centrifugal

Content• Mechanical System

• Key Components

• Motor Starters

• Application

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Mechanical System

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Layout

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EconomizerCentrifugal Compressor

Shell & Tube CondenserFull falling film

Evaporator

Control Panel

Layout

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Chiller Starter

Refrigerant System – Single stage

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Refrigerant System – Twin stage

Key Components

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Compressor

Motor

Gear Box

Compressor

Compressor

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Compressor

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◇IGV movable diffuser (Patent no. : ZL01 2 56825.2).Benefits: Elimination of Surge

Compressor

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Compressor

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Enclosed motor

Open-type motor

Evaporator

Condenser

MotorGearImpellerEntry guide vane Coupling

• Oil leakage of shaft seal

Oil bottle

Compressor

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Item Open-type Semi-hermetic

Key characteristics

1. Refrigerant spraying cooling; 2. The motor's operation environment is good and clean, and the service life is long; 3. The operating temperature is not affected by the external environment and the operating efficiency remains high; 4. No dedicated ventilation and air-conditioning equipment is needed for the equipment room, lowering the initial investment and operation costs; 5. The motor shaft is a large-gear shaft, preventing decentraction of the coupling; 6. IP54 protection grade is realized.

1. Open-type air-cooled motor, low cooling efficiency, loud noise, and large body; 2. the equipment room needs effective ventilation and cooling facilities, which should be able to maintain appropriate humidity, thus increasing power consumption; 3. the operation environmental temperature of the motor is high, shortening the service life; 4. the inspection and maintenance period is short and working intensity is high; 5. the alignment calibration of the motor, shaft seal and compressor is a key link of the operation process; flange connection is adopted, unlike soft connection that can absorb impacts in case of failures; if the coupling becomes a vibration source without proper measures, the failure rate of other parts such as the oil circuit will increase; the unit vibration is increased; 6. IP23 protection grade is realized.

Impacts on the power grid

The starting current is high, leading to a large impact on the power grid. Expensive software starter or frequency converter is

needed to reduce the impact on the power grid.

The starting current is low, with a small impact on the power grid.

Running noisesThe noises are loud

because the motor is exposed Low noises

Market shareIt is an alternative product manufactured by one or two

companies. It is mainly used for low-temperature cooling.It is a mainstream product,

which takes up a market share of over 80%.

Motor protectionHigh-temperature protection and over-current protection(Midea takes the following measures: 1. embedded PTC high-temperature protection; 2. PLC over-current protection; 3. thermal relay over-current protection. Different manufacturers take similar methods.)

Compressor

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Enclosed impeller

Open-type impeller

Refrigerant gas

Refrigerant gas

Discharge direction

Suction direction

Compressor

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Item Enclosed Open

Leakage

Low, enclosed structure, no leakage caused by tolerance clearance in the compression process

High, leakage of compression gas caused by tolerance clearance during starting, load increasing and decreasing of the compressor.

EfficiencyHigh level and stable operation, with few fluctuation

The efficiency drops with the service duration.

Repair and maintenanc

e

Convenient maintenance and low maintenance cost

Open structure, hard-to-maintain; the later maintenance cost is high due to leakage of refrigerant

Wearing Little wearingOpen-type, high requirement for precision tolerance (high-precision clearance fit between the impeller and compressor), causing wearing easily.

Market share

Over 95% Only used by one or two companies in the field

Compressor

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Gear acceleration transmission Direct motor driving

Compressor

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Item Features

Gear acceleration transmission

Compact unit structure, small body; relatively loud noises; wide application scope The main bearing surface is made of babbitt metal, with high intensity and oxidation resistance.

Direct connect motor transmission

The unit is large, but with low noises.

Note: TRANE CVGF series adopts gear acceleration transmission.

Compressor

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Compressor

Motor starters

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Starter typeType

Full voltage

Cross the line

Reduce voltage

Closed Y-∆

Auto transforme

r

Primary reactor

Solid state

VFD

VFD

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Closed Star Delta Application: < 690V

Advantage: Start Ampere: 33% of LRA; Reduce transition tap inrush ampere.

Disadvantage: Starting torque is 33% of cross the line and cannot

change; Only the motor with 3 phase, 6 poles available.

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Solid State StarterApplication: < 690V

Advantage: Start Ampere: 45% of LRA; No transition tap inrush ampere. The starting torque can be set.

Disadvantage: High price; Harmonic during starting.

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VFD StarterApplication: All

Advantage: Start Ampere: Smoothly and FLA; No tap inrush ampere. Energy saving in part load.

Disadvantage: High price; Harmonic during starting.

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Across The LineApplication: 6kV, 10kV, 11kV, 13.8kV

Advantage: Start Ampere: 100% of LRA; Large starting torque. Starter is simple and low price.

Disadvantage: High tap inrush ampere;

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Auto TransformerApplication: 10kV, 11kV, 13.8kV

Advantage: Start Ampere: 33% ~ 64% of LRA; Starting torque can be set.

Disadvantage: Large dimension and high price;

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Primary ReactorApplication: 10kV, 11kV, 13.8kV

Advantage: Start Ampere: 65% / 80% of LRA; Starting torque can be set.

Disadvantage: Large dimension and high price;

Applications

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Ice/Water storage

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Series System

Parallel System

Storage

Storage

Large

∆T

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COND: E/LWT 32/37℃ 32/40℃.

EVA: E/LWT 7/12℃ 5/13℃.

∆T 5 ℃ 8 ℃

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Thank You!