Large Tonnage ChillerAC Screw

Content• Mechanical System

• Key Components

• Control Logic

• Application

2

Mechanical System

3

Layout

4

Control panel

High Efficiency Shell & Tube Cooler

Condenser fans

Layout

5

Screw Compressor

Pressure gage

Condenser coils

Easily Accessible Filter Drier

Refrigerant System

6

Model:380, 500, 900, 1000

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Model:600, 720, 1200, 1420

Key Components

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Compressor

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Compressor

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Compressor

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Hermetic Semi-Hermetic Open

Compressor

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Item Open Hermetic Semi-Her.

MaintenanceEasy

Break the shell or change new one.

Easy

Leakage

Likelihood of Refrigerant and oil leakage, and it have to be charged.(Y brand)

Motor and rotors are in one shell, no leakage.

Shaft seal Yes, maintenance No

Mechanical room Motor heat reject out of compressor, it

need ventilation/cooling system. (e.g. 550RT chiller with input power 370kW, so motor heat 37kW have to taken by a 15HP AC.)

Just ventilation for flash air.

Compressor

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Open Hermetic Semi-Her.

Cooled Air Refrigerant

Noise High Lower Low

Application Few and refrigeration Few More

Brand York DB The others

Compressor

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Compressor

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  Single Twin Triple

FeaturesMain rotor(metal) and dual gaterotor (Non-metal, GR 1750RPM),tooth ratio 6:11 ,fitting complicated, flow losses.

Metal tooth ratio 5:6 fitting without flow losses.

Balanced rotor geometry and shorterscrew lengths

Efficiency Low efficiency, especial in low speed. Higher Higher

Parts

The higher speed, the less flow losses, so increase the friction loss, the gaterotor have to be replaced regularly.

No No

Oil - -Less

Brand Mcquay(Daikin) Midea and the others Carrier 23XRV

Compressor

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Air cooled — OpenRefrigerant cooled — Semi-/Hermetic

Features

1. Motor efficiency increase 3%;2. High maintenance cost;3. Need ventilation/cooling system, increase initial cost.4. Does not recharge refrigerant when burnout.

1. Better cooled efficiency;2. Longer operation life;3. Burnout can cause catastrophic damage to a chiller. The entire chiller must be cleaned, and the refrigerant replaced.

ProtectionWiring high temperature, current overload（ Midea： 1. PTC sensors in each motor winding coil； 2. Current overload in

MIC； 3. Overload relay.）

CompressorSuction valve Wiring box

Rotors

Discharge valve

Inner Check valve

Relief valve

Oil separator

10um Oil separator

Closed bearingOil heater

Oil server valve

Oil level switch

Motor

Gas filter

Overview

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Compressor

Throttle

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EEV TEV Capillary Orifice Butterfly valve

Throttle

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Item EEV TEV Capillary Orifice Butterfly valve

Components

Valve, controller,

sensor

Valve, bulb,

capillary tubeCapillary tube

Stainless steel

plate

Valve, driver, liquid

level sensor

Sensitivity

Precise flow regulation;

bi-flow operation as well as solenoid tight shut-off;

Wide range control.

Hysteresis but

stable

superheat.

Narrow range

control.

Narrow range

control.

Precise flow regulation,

bi-flow operation as well as solenoid tight shut-off

Wide range control

Price More expensive Benchmark Cheaper Cheap Most expensive

Throttle

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Throttle

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Control Logic

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Capacity ControlCR2/Y2CR1/Y1

CR4/Y4CR3/Y3

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Capacity Control

Discharge GasOil Pressure

Eco

CR4

CR2

Suction Gas CR1

CR3

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Capacity control

Compression process Capacity Control

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Fan control

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Fan controlDischarge (bar)

Fan Quantity

The higher/ lower

discharge pressure , the

more/less fans On.

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Applications

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Air side(T1/T3)

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Note: 100% load condition.

Cooler entering/leaving temperature difference at full loadMin~ Max 3~8C

Cooler LWT °C

Am

bie

nt

T °

C

Normal unit

High Ambient unit

Free cooling

31

NEW

4 Piping(Cooling/Heating/Hot water)

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NEW

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Thank You!