Lynxcool manufactures Semi-hermetic Two-Stage Screw Refrigeration Compressor Units for industrial and commercial refrigeration systems requiring stable low-temperature operation. The unit combines semi-hermetic screw compression technology with two-stage compression and an integrated economizer to improve refrigeration efficiency and maintain reliable performance under low evaporation temperatures.

Designed for cold storage, food processing, seafood freezing, pharmaceutical warehouses, and industrial process cooling, this factory-assembled refrigeration unit operates at evaporation temperatures down to -50°C. The semi-hermetic structure removes the need for external shaft seals, helping reduce refrigerant leakage risks and simplify routine maintenance.

With skid-mounted assembly, PLC-based control, and flexible capacity regulation, the unit supports quick installation, automatic operation, and system expansion for different refrigeration requirements.

Product Range

Working Principle of Semi-hermetic Two-Stage Screw Refrigeration Compressor Unit

The Semi-hermetic Two-Stage Screw Refrigeration Compressor Unit works by compressing refrigerant through two screw compression stages to achieve efficient cooling under low-temperature operating conditions. The refrigeration cycle begins when low-pressure refrigerant vapor enters the first compression stage, where the twin screw rotors compress the refrigerant to an intermediate pressure level.

After intermediate compression, the refrigerant passes through the built-in economizer system, where additional refrigerant injection improves refrigerant flow and increases cooling efficiency. The second compression stage further increases the refrigerant pressure before the high-pressure gas enters the condenser for heat rejection.

During operation, the semi-hermetic motor is cooled by suction refrigerant gas, maintaining stable motor temperature and reducing the need for additional cooling components. The PLC control system continuously monitors operating parameters and adjusts compressor capacity according to refrigeration demand, ensuring stable temperature control and efficient energy use.

Compared with traditional single-stage screw compressors, the two-stage compression process reduces discharge temperature, improves performance under high compression ratios, and allows reliable operation in applications requiring evaporation temperatures down to -50°C.

Key Features

Semi-hermetic Screw Compressor Structure

The semi-hermetic design integrates the motor and compressor into a sealed housing, removing the external shaft seal commonly used in open-type compressors. This structure reduces potential refrigerant leakage points and protects internal components from external contamination.

The motor is cooled by suction refrigerant gas during operation, allowing stable performance without additional motor cooling equipment. Combined with IP54 protection, the compressor unit is suitable for continuous operation in industrial refrigeration environments.

Two-stage Compression Technology

The two-stage compression system divides the total pressure ratio into two compression stages, reducing the workload of each stage and improving operating stability under low-temperature conditions.

This design lowers discharge temperature, reduces thermal stress on compressor components, and maintains efficient operation when evaporation temperatures reach -50°C. It is particularly suitable for deep freezing, seafood processing, and low-temperature storage applications where single-stage systems may experience efficiency loss.

Built-in Economizer System

The integrated economizer improves refrigeration cycle performance by injecting intermediate-pressure refrigerant into the compression process. This increases refrigerant circulation and improves cooling capacity under low-temperature operating conditions.

Compared with conventional systems without economizer technology, the unit provides improved energy efficiency and more stable performance during heavy-load operation, helping reduce long-term operating costs.

Factory-Assembled Skid Design

All major components, including the screw compressor, oil separator, piping system, valves, and control cabinet, are assembled on a single skid before shipment.

This integrated structure reduces onsite installation work and helps shorten commissioning time. The compact footprint also makes the unit suitable for refrigeration rooms with limited installation space or retrofit projects requiring equipment replacement.

Intelligent PLC Control System

The compressor unit is equipped with PLC-based automatic control and touchscreen operation interface for convenient system management.

The control system monitors operating parameters including pressure, temperature, compressor status, and safety alarms. It supports automatic capacity adjustment, remote communication, and integration with refrigeration management systems through standard communication protocols.

Flexible Refrigerant Compatibility

The unit supports multiple refrigerants to meet different regional requirements and refrigeration system designs. Available refrigerants include R134a, R404A, R507A, and R449A, with customized configurations available for specific project requirements.

This flexibility allows the compressor unit to be applied in various commercial and industrial refrigeration environments.

Technical Parameters

The Semi-hermetic Two-Stage Screw Refrigeration Compressor Unit’details are following:

Parameter	Specification
Compressor Type	Semi-hermetic twin screw compressor
Compression Method	Two-stage compression with economizer injection
Cooling Capacity	30 kW - 800 kW
Evaporating Temperature	-20°C to -50°C
Condensing Temperature	+30°C to +45°C
Capacity Regulation	25% - 100% stepless adjustment
Refrigerant	R134a / R404A / R507A / R449A
Motor Cooling	Suction gas cooling
Motor Voltage	380V / 3 Phase / 50Hz
Optional Voltage	460V / 60Hz
Protection Level	IP54
Control System	PLC + Touchscreen HMI
COP Range	2.0 - 2.8
Noise Level	≤78 dB(A) at 1 meter

Applications

Cold Storage and Food Processing

The compressor unit provides stable cooling performance for cold rooms, distribution warehouses, poultry processing, meat production, and seafood freezing facilities. Its low-temperature operating capability helps maintain consistent refrigeration conditions during continuous production.

Pharmaceutical Refrigeration

For pharmaceutical storage and temperature-sensitive products, the unit provides reliable cooling control with automatic monitoring functions to maintain stable operating conditions and reduce temperature fluctuations.

Industrial Process Cooling

The system is suitable for industrial applications including chemical processing, electronics manufacturing, textile production, and other processes requiring continuous temperature control and reliable cooling performance.

Energy Efficiency and Operating Benefits

The two-stage compression structure improves efficiency under high compression ratio conditions by reducing the pressure load of each compression stage. Lower discharge temperature helps reduce thermal stress and improve compressor service life.

The built-in economizer increases refrigeration cycle efficiency by improving refrigerant circulation, while the semi-hermetic structure reduces leakage risks compared with traditional open-type compressor designs.

The combination of efficient compression technology, automatic control, and skid-mounted integration helps customers reduce energy consumption and simplify long-term operation management.

Installation and Maintenance

Installation Requirements

The factory-assembled skid structure reduces onsite installation requirements. After positioning the unit, customers mainly need to complete refrigerant piping connections, electrical wiring, and control system commissioning.

The compact design allows flexible installation in newly constructed refrigeration facilities as well as existing systems requiring equipment replacement or capacity expansion.

Maintenance Requirements

The semi-hermetic structure reduces routine maintenance requirements by eliminating external shaft seals and protecting internal components within a sealed housing.

Daily maintenance mainly includes checking refrigerant charge, oil level, operating pressure, temperature parameters, and PLC alarm records. Standardized components also simplify spare parts replacement and reduce downtime.

Why Choose Lynxcool?

Industrial Refrigeration Manufacturing Experience

Lynxcool specializes in refrigeration equipment for cold chain, food processing, and industrial cooling applications. The company develops compressor units based on different temperature requirements, cooling capacities, and operating environments.

Engineering Support Before Delivery

Lynxcool provides technical support including refrigeration system selection, cooling capacity calculation, equipment configuration, installation drawings, and operation recommendations to help customers select suitable solutions.

Factory Assembly and Testing

Each compressor unit is assembled and inspected before shipment. Testing procedures include compressor operation checks, control system verification, safety protection testing, and operating parameter confirmation.

Customized Refrigeration Solutions

Lynxcool supports customization of compressor capacity, refrigerant configuration, control systems, and equipment layout according to specific project requirements.

Global Service Support

Technical consultation, spare parts support, and remote troubleshooting services are available to help international customers maintain stable refrigeration system operation.

FAQ

What is a Semi-hermetic Two-stage Screw Refrigeration Compressor Unit?

A Semi-hermetic Two-stage Screw Refrigeration Compressor Unit combines a sealed screw compressor structure with two-stage compression technology. It is designed for refrigeration systems requiring stable operation under low evaporation temperatures and high compression ratios.

What are the advantages of two-stage compression?

Two-stage compression reduces the pressure ratio handled by each compression stage, lowering discharge temperature and improving efficiency during low-temperature operation. It is suitable for applications such as freezing systems and cold storage.

What temperature range can this compressor unit achieve?

The unit can operate at evaporation temperatures from -20°C to -50°C depending on refrigerant selection, system configuration, and operating conditions.

Which refrigerants are available?

Standard refrigerant options include R134a, R404A, R507A, and R449A. Customized refrigerant configurations can be provided according to project requirements.

What industries use this refrigeration unit?

It is widely used in food processing, seafood freezing, cold storage, pharmaceutical refrigeration, chemical cooling, and industrial process cooling.

Does the unit require complicated installation?

The skid-mounted design integrates major components before delivery, reducing onsite piping work and simplifying installation and commissioning.

How does the semi-hermetic design reduce maintenance?

The sealed structure eliminates external shaft seals and reduces refrigerant leakage risks, helping lower maintenance frequency during long-term operation.

Can the cooling capacity be adjusted?

Yes. The unit supports 25%-100% stepless capacity regulation, allowing cooling output to match different load requirements.