Understanding Mycom Screw Compressor N200 Ammoniafreon: Standards, Properties, and Applications

Types of Mycom N200 Screw Compressors for Ammonia & Freon Applications

The Mycom N200 screw compressor is a high-performance refrigeration solution widely used in industrial cooling systems. Designed for both ammonia (NH₃) and freon-based refrigerants, the N200 series offers reliability, efficiency, and adaptability across various operating conditions. These compressors are engineered to meet the demands of commercial refrigeration, food processing, cold storage, and chemical industries.

Different configurations of the Mycom N200 are available to suit specific operational needs, including pressure requirements, energy efficiency goals, spatial constraints, and load variability. Understanding the types helps in selecting the optimal model for maximum performance and cost-effectiveness.

Single-Stage Mycom Screw Compressors

Designed for straightforward compression tasks, these units perform the entire refrigerant compression process in one step, making them ideal for low to moderate pressure differentials.

Advantages

• Simple mechanical design with fewer moving parts
• Lower initial investment and installation cost
• Easier maintenance and troubleshooting
• Energy-efficient for stable, low-demand applications

Limitations

• Less efficient under high compression ratios
• Limited suitability for extreme temperature differentials
• Potential overheating with high-pressure demands

Best for: Small to medium cold storage, light industrial use, constant cooling loads

Two-Stage Mycom Screw Compressors

These advanced compressors divide the compression process into two phases—initial low-pressure compression followed by final high-pressure compression—often with intercooling between stages.

Advantages

• Higher overall efficiency in high-pressure systems
• Reduced discharge temperature improves reliability
• Better performance across wide temperature ranges
• Extended compressor lifespan due to lower thermal stress

Limitations

• Higher upfront cost and complexity
• Requires more space and additional components (e.g., intercooler)
• More involved maintenance procedures

Best for: Large-scale refrigeration, deep-freeze applications, chemical processing plants

Vertical Mycom Screw Compressors

A space-saving alternative to traditional horizontal models, vertical compressors are mounted upright, optimizing floor space in compact facilities.

Advantages

• Compact footprint ideal for space-constrained environments
• Robust construction for high refrigerant flow rates
• Improved accessibility for servicing internal components
• Better oil drainage and distribution due to orientation

Limitations

• May require specialized mounting and foundation
• Taller profile can limit installation in low-ceiling areas
• Fewer options available compared to horizontal models

Best for: Urban cold storage, retrofit projects, facilities with limited floor space

Variable Speed Drive (VSD) Mycom Screw Compressors

Equipped with frequency inverters, VSD models adjust motor speed based on real-time cooling demand, offering dynamic control over capacity and energy use.

Advantages

• Significant energy savings (up to 35–50% under partial loads)
• Precise temperature control with minimal fluctuations
• Reduced mechanical stress and wear due to soft starts
• Adaptable to variable process loads and seasonal changes

Limitations

• Higher initial purchase and setup cost
• Requires skilled technicians for configuration and maintenance
• Potential electromagnetic interference (EMI) without proper shielding

Best for: Facilities with fluctuating loads, data centers, pharmaceutical storage, energy-conscious operations

Type	Energy Efficiency	Application Range	Maintenance Needs	Ideal Use Case
Single-Stage	Good	Narrow (Low-Moderate Pressure)	Low	Stable cooling loads, small facilities
Two-Stage	Excellent	Wide (High Pressure/Differential)	Moderate	Industrial refrigeration, deep freeze
Vertical	Good	Medium to High Flow	Moderate	Space-limited installations
VSD (Variable Speed)	Outstanding	Dynamic/Variable Loads	Moderate-High	Energy-sensitive, variable demand environments

Expert Tip: When using ammonia (NH₃) refrigerant, ensure all Mycom compressor seals and gaskets are compatible with ammonia's corrosive properties. Regular leak detection and proper ventilation are critical for safety and system longevity.

Installation Note: For VSD models, always pair the compressor with a dedicated line reactor or harmonic filter to protect the inverter and comply with electrical standards, especially in sensitive industrial environments.

What Makes the Mycom Screw Compressor N200 (Ammonia & Freon) Exceptionally Durable?

The Mycom N200 screw compressor is engineered for long-term reliability in demanding industrial refrigeration environments. Designed to operate efficiently with both ammonia (NH₃) and freon-based refrigerants, the N200 stands out due to its robust construction, advanced engineering, and use of high-performance materials. Below are the key factors that contribute to its superior durability and extended service life.

Core Durability Features of the Mycom N200 Compressor

Heavy-Duty Construction

The Mycom N200 features a rugged, industrial-grade housing constructed from high-strength materials specifically selected to resist the corrosive properties of ammonia and freon refrigerants. Ammonia, while highly efficient, is known for its aggressive chemical behavior, especially in the presence of moisture. The compressor’s casing is treated and built to withstand these conditions without degradation.

This heavy-duty design ensures resilience against mechanical stress, vibration, and environmental exposure, making it ideal for continuous operation in harsh industrial settings such as food processing plants, cold storage facilities, and chemical plants. The structural integrity of the unit significantly reduces the risk of fatigue-related failures, contributing to a longer operational lifespan.

Premium-Quality Bearings

At the heart of smooth and reliable operation are the high-precision, premium-grade bearings used in the N200 compressor. These bearings support the rotating shafts and screw rotors under extreme loads and elevated temperatures—common in high-capacity refrigeration cycles.

Engineered for minimal friction and maximum load-bearing capacity, these bearings reduce wear and heat generation during prolonged use. They are also designed with enhanced seals to prevent lubricant leakage and contamination, ensuring consistent performance. Their reliability directly translates into reduced downtime, lower maintenance costs, and improved overall compressor longevity.

Screw Rotors with Wear-Resistant Coating

The twin screw rotors are the core working components of any screw compressor. In the Mycom N200, these rotors are precision-machined and coated with a specialized wear-resistant surface treatment that minimizes metal-to-metal contact during operation.

This advanced coating not only reduces friction and energy loss but also protects against pitting, scoring, and abrasion caused by particulates or lubricant breakdown. By maintaining tight tolerances over time, the rotors preserve compression efficiency and prevent performance degradation. This design choice is critical for maintaining peak efficiency and preventing premature failure in continuous-duty applications.

Efficient Cooling System

Thermal management is crucial for compressor durability. The Mycom N200 incorporates an optimized internal cooling system that effectively dissipates heat generated during the compression process. This system ensures that rotor temperatures remain within safe operating limits, preventing thermal expansion, warping, or lubricant breakdown.

By maintaining stable internal temperatures, the cooling mechanism reduces thermal stress on critical components such as bearings, seals, and rotor assemblies. This proactive heat control extends component life and enhances the compressor’s ability to perform reliably under high-load conditions, even in high-ambient-temperature environments.

Advanced Sealing Technology

Leak prevention is vital when handling refrigerants like ammonia, which can be hazardous if released, and freon, which is costly and environmentally regulated. The Mycom N200 employs state-of-the-art sealing systems—including mechanical face seals and labyrinth seals—that effectively contain refrigerant within the compression chamber while keeping contaminants out.

These seals also retain lubricating oil where it’s needed, ensuring consistent lubrication of moving parts. Proper sealing prevents moisture ingress, particle contamination, and oil leakage—all of which can accelerate wear and lead to catastrophic failure. The result is a cleaner, more stable internal environment that supports long-term reliability.

Material Compatibility & Corrosion Resistance

Beyond the housing, internal components are selected for compatibility with both ammonia and freon refrigerants. Materials such as stainless steel, specialized alloys, and non-reactive elastomers are used in critical areas to resist chemical attack and galvanic corrosion.

This holistic approach to material selection ensures that every part of the compressor—from fasteners to internal piping—can endure prolonged exposure to aggressive refrigerants. It eliminates weak points in the system and supports the compressor’s reputation for durability in mixed-refrigerant applications.

Durability Feature	Benefit	Industrial Impact
Heavy-Duty Housing	Resists corrosion and mechanical stress	Longer service life in harsh environments
Premium Bearings	Reduced friction and heat under load	Fewer breakdowns and lower maintenance costs
Wear-Resistant Rotors	Maintains efficiency and tight tolerances	Sustained performance over thousands of hours
Effective Cooling System	Prevents overheating and thermal deformation	Stable operation under peak loads
Advanced Sealing	Prevents leaks and contamination	Improved safety and environmental compliance

Maintenance Tips to Maximize Durability

Regular Oil Analysis: Monitor lubricant condition to detect contamination or degradation early. Change oil according to manufacturer recommendations to maintain optimal protection.

Vibration Monitoring: Use sensors to detect abnormal vibrations, which may indicate bearing wear or misalignment, allowing for predictive maintenance.

Seal Inspections: Periodically check seals for signs of wear or leakage, especially in ammonia systems where safety is paramount.

Cooling System Maintenance: Ensure cooling lines and jackets are clean and free from blockages to maintain effective heat dissipation.

Professional Servicing: Schedule routine inspections by qualified technicians to verify alignment, tension, and overall system health.

Important: Always follow the Mycom service manual and safety guidelines when operating or maintaining the N200 compressor, especially when handling ammonia. Improper maintenance or use of non-approved parts can compromise safety, reduce efficiency, and shorten equipment life. Proper care ensures maximum return on investment and uninterrupted refrigeration performance.

Industrial Applications of Mycom Screw Compressor N200 (Ammonia & Freon)

The Mycom N200 screw compressor is a high-performance industrial refrigeration solution widely used across multiple sectors due to its reliability, energy efficiency, and compatibility with both ammonia (NH₃) and freon-based refrigerants. Its robust design enables stable operation under demanding conditions, making it ideal for large-scale cooling applications where temperature precision and system longevity are critical. Below are the key industries leveraging the Mycom N200 compressor to optimize their operations.

Food and Beverage Industry

The Mycom N200 screw compressor plays a vital role in preserving the freshness and safety of perishable goods through precise, low-temperature refrigeration. Ammonia, a highly efficient and environmentally friendly refrigerant, is commonly used in this sector due to its excellent thermodynamic properties and low global warming potential (GWP).

• Used in chilling and freezing processes for meat, poultry, seafood, and dairy products to inhibit bacterial growth
• Enables consistent cold storage in large-scale warehouses and processing plants
• Supports blast freezing systems that rapidly reduce product temperature to maintain texture and nutritional value
• Ammonia’s high latent heat of vaporization ensures efficient heat removal with lower energy consumption

Key benefit: Ensures compliance with food safety standards (e.g., HACCP, FDA) by maintaining uninterrupted cold environments.

Cold Chain Logistics

In cold chain logistics, maintaining a consistent temperature from production to delivery is essential to prevent spoilage and ensure product integrity. The Mycom N200 compressor delivers reliable refrigeration in transport refrigeration units and temperature-controlled storage facilities.

• Widely used in refrigerated trucks, railcars, and shipping containers for transporting frozen and chilled goods
• Freon-based refrigerants (such as R-134a or R-404A) are often preferred in mobile applications due to their stability and safety in enclosed systems
• Provides precise temperature control for pharmaceuticals, vaccines, and biologics requiring strict thermal management
• Also supports floriculture transport, preserving the freshness of cut flowers during long-distance shipment

Critical advantage: Offers rapid cooling response and minimal temperature fluctuation, crucial for time-sensitive shipments.

Chemical Processing

In chemical manufacturing, many reactions are exothermic and require continuous cooling to remain stable and safe. The Mycom N200 compressor provides dependable refrigeration for process cooling, condensation, and cryogenic applications.

• Maintains low temperatures in reactors, distillation columns, and crystallization units to control reaction rates
• Prevents thermal runaway in sensitive chemical syntheses, enhancing operational safety
• Ammonia's wide operating range allows adaptation to various pressure and temperature requirements across different chemical processes
• Freon variants offer oil compatibility and corrosion resistance in systems handling reactive or acidic compounds

Technical insight: Ammonia systems are often integrated with secondary coolants (e.g., glycol) to isolate refrigerant from direct contact with process equipment.

HVAC Systems

For large commercial and industrial buildings, the Mycom N200 screw compressor serves as a core component in centralized HVAC systems, providing energy-efficient climate control.

• Delivers high cooling capacity with variable load modulation, adapting to changing thermal demands
• Enhances indoor air quality by maintaining consistent humidity and temperature levels
• Ideal for data centers, hospitals, manufacturing plants, and shopping complexes where uninterrupted cooling is essential
• Energy-efficient operation reduces operational costs and supports sustainability goals

Efficiency note: Equipped with advanced control systems that optimize compressor staging and reduce power peaks.

Industrial Cooling Systems

The N200 compressor is engineered to support critical machinery cooling in heavy industries, preventing overheating and ensuring continuous operation.

• Used in power plants, steel mills, and plastics manufacturing to cool hydraulic systems, gearboxes, and extruders
• Ammonia’s superior heat transfer properties make it ideal for high-heat-flux applications
• Protects sensitive electronic controls and motors from thermal degradation
• Supports closed-loop cooling circuits that minimize water usage and environmental impact

Reliability factor: Designed for 24/7 operation with minimal maintenance, reducing downtime and increasing productivity.

Refrigerant Comparison: Ammonia vs. Freon

Understanding the differences between ammonia and freon refrigerants helps in selecting the right configuration for specific industrial needs.

Feature	Ammonia (NH₃)	Freon (e.g., R-134a, R-404A)
Thermal Efficiency	Excellent – high latent heat and coefficient of performance (COP)	Good – moderate efficiency, suitable for precise control
Environmental Impact	Zero ODP, GWP = 0 – eco-friendly and sustainable	Low ODP, but high GWP – subject to regulatory phase-downs
Safety	Toxic and flammable – requires proper ventilation and safety protocols	Non-toxic and non-flammable – safer for occupied spaces
Application Suitability	Large-scale industrial systems, cold storage, process cooling	Mobile units, HVAC, pharmaceutical storage, retail refrigeration
Maintenance Needs	Requires specialized training and leak detection systems	Easier handling and service, compatible with standard tools

Professional Insight: When selecting between ammonia and freon configurations for the Mycom N200 compressor, consider the scale of operation, safety regulations, environmental policies, and total cost of ownership. Ammonia systems typically offer lower operating costs and better long-term sustainability, while freon systems provide ease of installation and compliance with safety standards in public or confined areas.

Additional Considerations for Optimal Performance

• System Integration: Ensure compatibility with existing controls, sensors, and piping infrastructure for seamless operation
• Oil Management: Proper oil separation and return systems are critical, especially in ammonia applications, to maintain compressor efficiency
• Corrosion Protection: Use appropriate materials (e.g., stainless steel, coated surfaces) when handling ammonia to prevent degradation
• Energy Monitoring: Integrate with Building Management Systems (BMS) for real-time performance tracking and predictive maintenance
• Regulatory Compliance: Adhere to local and international standards such as ASHRAE, IIAR, and EPA guidelines for refrigerant handling and emissions

How to Choose the Mycom Screw Compressor N200 for Ammonia & Freon Applications

Selecting the right compressor for your refrigeration system is crucial for long-term performance, safety, and efficiency. The Mycom N200 screw compressor is a robust, industrial-grade solution designed to handle both ammonia (R717) and various freon-based refrigerants (such as R22, R134a, or R404A). This guide provides a comprehensive overview of key considerations when choosing the Mycom N200, helping buyers make informed decisions based on their specific operational needs, environmental conditions, and budget constraints.

Safety Note: Ammonia is a toxic and flammable refrigerant requiring strict handling protocols, proper ventilation, and leak detection systems. Always ensure compliance with local safety regulations and consult with certified HVAC/R engineers before installation.

Key Factors to Consider When Choosing the Mycom N200 Compressor

• Refrigerant Compatibility and System Design

  The Mycom N200 is engineered for dual compatibility with both ammonia and freon refrigerants, making it a versatile option for a wide range of industrial refrigeration applications. Ammonia is favored in large-scale cold storage, food processing, and freezing plants due to its excellent thermodynamic properties, zero ozone depletion potential (ODP), and low global warming potential (GWP). Freon-based refrigerants, while less environmentally friendly, are often used in retrofit systems or where safety codes restrict ammonia use.

  When selecting the N200, confirm that the internal materials (seals, gaskets, lubricants) are compatible with your chosen refrigerant. For ammonia systems, the compressor must use oil that is miscible with ammonia (typically mineral oil), while freon systems may require synthetic POE or PAG oils. Always verify the model variant is specifically rated for your refrigerant type to avoid premature failure.

• Pressure and Temperature Ratings

  The operating pressure and temperature range of your refrigeration system must align with the N200’s design specifications. This compressor is built to handle high discharge pressures and extreme temperature differentials, making it ideal for low-temperature freezing applications (-40°C and below) as well as medium-temperature chilling processes.

  Review the compressor’s maximum allowable working pressure (MAWP), suction and discharge pressure limits, and ambient temperature ratings. Operating outside these parameters can lead to mechanical stress, oil breakdown, or catastrophic failure. For example, in ammonia systems, high discharge temperatures can degrade lubrication and increase the risk of carbon buildup. Always perform a system load calculation and consult performance curves provided by Mycom to ensure proper match-up.

• Energy Efficiency and Operational Costs

  Energy consumption is one of the largest operating expenses in refrigeration systems. The Mycom N200 offers high volumetric efficiency and reliable performance, but buyers should consider models equipped with a Variable Frequency Drive (VFD) for even greater energy savings. VFDs allow the compressor to modulate speed based on cooling demand, reducing power consumption during partial-load conditions—common in most industrial settings.

  Additionally, look for features like slide valves for capacity control, efficient motor designs (IE3 or IE4), and integrated heat recovery options. Over time, an energy-efficient compressor can significantly reduce electricity bills and lower the total cost of ownership (TCO), even if the initial investment is higher.

• Maintenance Requirements and Long-Term Reliability

  The Mycom N200 is known for its durability and long service life in demanding environments. However, regular maintenance is essential to sustain peak performance. Key maintenance tasks include checking oil levels and quality, inspecting suction and discharge valves, monitoring bearing condition, and verifying seal integrity—especially critical in ammonia systems where leaks can pose safety hazards.

  Consider the availability of spare parts, technical support, and service expertise in your region. Compressors used in continuous operation should follow a preventive maintenance schedule (e.g., every 2,000–4,000 hours). The N200’s robust rotor design and heavy-duty bearings contribute to reduced downtime and extended maintenance intervals, making it a reliable choice for mission-critical applications.

• Initial Cost vs. Total Cost of Ownership (TCO)

  While the upfront cost of the Mycom N200 may be higher than some alternatives, it’s essential to evaluate the total cost of ownership over its lifespan. This includes purchase price, installation, energy consumption, maintenance, and potential downtime costs.

  Although ammonia systems may require additional safety infrastructure (e.g., detectors, ventilation), the refrigerant itself is inexpensive and highly efficient. Freon systems, on the other hand, face rising refrigerant costs due to environmental regulations (e.g., F-gas regulations). Investing in a high-quality, energy-efficient compressor like the N200 often results in lower operational costs and a faster return on investment (ROI), especially in high-utilization environments.

Selection Factor	Ammonia (R717) Considerations	Freon (e.g., R22, R404A) Considerations	Recommendations for N200
Refrigerant Compatibility	Requires ammonia-rated seals and mineral oil	Compatible with POE/PAG oils and standard seals	Select model variant specifically designed for your refrigerant
Operating Pressure	High discharge pressure common in low-temp apps	Moderate to high pressure depending on type	Verify MAWP and suction/discharge ratings
Energy Efficiency	High COP; ideal for large systems	Lower efficiency than ammonia in many cases	Opt for VFD models and IE3+ motors
Maintenance	Regular leak checks required; oil changes every 8,000–10,000 hrs	Fewer safety concerns; oil change every 6,000–8,000 hrs	Follow OEM schedule; use condition monitoring
Total Cost of Ownership	Low refrigerant cost; higher safety infrastructure cost	High refrigerant cost; simpler installation	Evaluate 5–10 year TCO, not just purchase price

Expert Tip: When integrating the Mycom N200 into a new or existing system, work with a qualified refrigeration engineer to perform a full system design analysis. This ensures optimal compressor selection, correct piping, proper oil management, and compliance with safety and environmental standards.

Final Recommendations

• Confirm the exact N200 model number and refrigerant compatibility with the manufacturer or supplier
• Ensure your facility meets safety and ventilation requirements, especially for ammonia systems
• Consider future scalability—choose a compressor that can accommodate load increases
• Train maintenance staff on proper handling procedures and emergency response
• Keep detailed service records to track performance and predict component life

The Mycom N200 screw compressor is a proven, high-performance solution for industrial refrigeration. By carefully evaluating refrigerant compatibility, operating conditions, energy efficiency, maintenance needs, and total cost of ownership, buyers can confidently select a compressor that delivers reliable, efficient, and safe operation for years to come.

Frequently Asked Questions About the Mycom N200 Screw Compressor

Q1: What is the Mycom N200 screw compressor dedicated to?

The Mycom N200 is a heavy-duty industrial screw compressor engineered for high-performance applications. It is primarily dedicated to large-scale refrigeration systems, especially in environments requiring continuous and reliable cooling, such as food processing plants, cold storage warehouses, and industrial manufacturing facilities.

Thanks to its robust design and advanced engineering, the Mycom N200 excels in maintaining stable operation under high thermal loads, making it a preferred choice for mission-critical refrigeration infrastructure.

Q2: What are the advantages of the Mycom N200 for ammonia refrigeration systems?

The Mycom N200 is particularly well-suited for ammonia (NH₃) refrigeration systems, which are widely used in industrial settings due to ammonia’s high efficiency and low environmental impact. Key advantages include:

• High Energy Efficiency: Optimized rotor profiles and compression processes reduce power consumption while maximizing cooling output.
• Precise Capacity Control: Equipped with stepless or variable capacity modulation, allowing fine-tuned response to cooling demands.
• Low Maintenance Needs: Durable components and simplified oil management systems minimize downtime and service frequency.
• Safety & Compatibility: Designed with materials and seals resistant to ammonia, ensuring long-term reliability and leak-free operation.
• Environmental Benefits: Ammonia is a natural refrigerant with zero ozone depletion potential (ODP) and negligible global warming potential (GWP), aligning with sustainability goals.

These features make the Mycom N200 an ideal solution for industrial refrigeration plants seeking efficient, eco-friendly, and cost-effective operations.

Q3: How does the Mycom N200 function in freon refrigeration systems?

While best known for ammonia applications, the Mycom N200 can also be configured for use with fluorinated refrigerants (commonly referred to as "freon" or HFCs/HFOs). In these systems, it delivers smooth and efficient refrigeration cycles by:

• Utilizing precision-engineered twin-screw rotors to compress refrigerant vapor with minimal leakage and high volumetric efficiency.
• Maintaining consistent cooling performance across varying ambient and load conditions.
• Supporting tight temperature control essential for sensitive processes like pharmaceutical storage, chemical processing, and climate-controlled environments.
• Integrating with modern control systems for real-time monitoring and adaptive operation.

The compressor's versatility allows it to support both retrofit projects and new installations using regulated or next-generation low-GWP refrigerants, ensuring compliance with evolving environmental standards.

Q4: Is the Mycom N200 suitable for variable load conditions?

Yes, the Mycom N200 is exceptionally well-suited for variable load conditions thanks to its advanced capacity modulation technology. Depending on the model and configuration, it offers:

• Variable-Speed Drive (VSD) Options: Allows the motor speed to adjust dynamically based on cooling demand, significantly improving part-load efficiency.
• Stepless Capacity Control: Provides continuous adjustment from 10% to 100% capacity, avoiding the inefficiencies of on/off cycling.
• Adaptive Performance: Responds quickly to fluctuating thermal loads, maintaining stable suction pressures and system efficiency.
• Energy Savings: Reduces electricity consumption during periods of low demand, lowering operational costs and extending equipment life.

This adaptability makes the Mycom N200 ideal for facilities with changing production schedules, seasonal demand variations, or multi-zone cooling requirements.

Q5: What features contribute to the durability and reliability of the Mycom N200?

The Mycom N200 is built for long-term, uninterrupted service in demanding industrial environments. Its durability and reliability stem from several key design and engineering features:

Feature	Description	Benefit
Robust Construction	Heavy-duty cast iron housing and reinforced frame.	Resists vibration, thermal stress, and mechanical shock.
High-Quality Materials	Corrosion-resistant coatings and wear-resistant alloys in critical components.	Extends service life, especially in harsh environments.
Advanced Sealing Technology	Double mechanical seals with nitrogen barrier protection (especially for ammonia).	Prevents gas leakage and oil contamination, enhancing safety and efficiency.
Precision Rotor Design	Optimized screw profile with tight manufacturing tolerances.	Ensures smooth operation, low noise, and high volumetric efficiency.
Integrated Monitoring Systems	Sensors for temperature, pressure, vibration, and oil condition.	Enables predictive maintenance and early fault detection.

Together, these features ensure the Mycom N200 operates reliably for thousands of hours with minimal maintenance, reducing lifecycle costs and maximizing uptime in industrial refrigeration systems.