Summary of technology trends: In accordance with the commitments to implement the Kigali Amendment to the Montreal Protocol and Vietnam's Net Zero 2050 goals, artificial HFC refrigerants (such as R404A, R507A, R134a) with high global warming potential (GWP) are subject to import quotas and gradual phasing out. Natural Refrigerant Ammonia (NH3 – R717) and Carbon Dioxide (CO2 – R744) With a near-zero GWP and superior heat transfer efficiency, it is becoming a mandatory standard for large logistics cold storage facilities and ESG-compliant food processing plants.
The global refrigeration and air conditioning industry is entering its third green transformation. Following the successful elimination of ozone-depleting refrigerants (CFCs like R12, HCFCs like R22), the current focus is on reducing greenhouse gas emissions from the HFC (Hydrofluorocarbon) group.
In Vietnam, with the promulgation of Decree 06/2022/ND-CP and Decision 496/QD-TTg on the roadmap for managing and eliminating ozone-depleting substances, investors in cold storage facilities and export processing plants are facing a strategic dilemma: Continue investing in Freon systems with the risk of refrigerant shortages and skyrocketing gas refill prices in the next 5-10 years, or embrace the technology. Natural Refrigerants?
1. Comparison table of environmental indicators and thermodynamic performance
To assess the superiority of natural refrigerants over synthetic Freon gases, refrigeration engineers compare them using four core parameters: ODP (Ozone Depletion Potential), GWP (Global Warming Potential), COP (Coefficient of Refrigeration Efficiency), and Latent Heat of Vaporization.
| Refrigerant | Chemical symbols | ODP Index | GWP (Gross Productivity) Index (100 years) | Latent heat of vaporization (kJ/kg at 0°C) | Kigali Management Roadmap |
|---|---|---|---|---|---|
| Ammonia (R717) | NH3 | 0 | 0 | 1,262 kJ/kg | Encouraged for permanent use. |
| Carbon Dioxide (R744) | CO2 | 0 | 1 | 231 kJ/kg | Encouraged for permanent use. |
| R404A (Freon) | HFC mixture | 0 | 3.922 | 175 kJ/kg | Currently facing significant price cuts and new top-up bans in the EU. |
| R507A (Freon) | HFC mixture | 0 | 3.985 | 169 kJ/kg | Currently undergoing drastic cuts. |
| R134a (Freon) | CF3CH2F | 0 | 1.430 | 198 kJ/kg | Restricted by route |
Observations based on thermodynamic data: The latent heat of vaporization of NH3 reaches 1,262 kJ/kg, much higher 7 times compared to R404A (175 kJ/kg). This means that to produce the same cooling capacity, the mass flow rate of NH3 refrigerant that needs to be circulated is many times lower, allowing for the use of smaller pipe diameters and compressors with smaller swept volumes, helping Reduced actual electricity consumption from 15% to 25%.
The central compressor station system using NH3 refrigerant at the AJ Total Long Hau smart cold storage project was designed and installed by Tan Long.
2. Breakthrough technological solution: Cascade NH3/CO2 continuous refrigeration system
Although NH3 is the most energy-efficient refrigerant, its irritating properties and pungent odor when leaked restrict its direct use in high-traffic processing areas or multi-story automated cold storage facilities. To thoroughly address this issue, the solution... Cascade System NH3/CO2 born:
- High-temperature circuit (NH3 circuit): Ammonia operates in a closed-loop system within a central compressor station located separately outside the workshop. NH3 condenses CO2 vapor in the Cascade heat exchanger (Cascade Condenser). The amount of NH3 charged is reduced to 85% compared to traditional flooded NH3 systems.
- Low temperature circuit (CO2 circuit): The CO2 refrigerant (R744) is completely harmless, non-toxic, and non-flammable, and is circulated through the deep-freeze storage rooms (-25°C to -30°C) and IQF conveyor freezing chambers (-45°C to -50°C).
- Outstanding technical advantages: The CO2 evaporation pressure at -40°C remains positive (approximately 10 bar), completely eliminating the risk of humid air entering the pipes and causing clogging – a chronic technical problem in ultra-low temperature Freon systems. The ultra-small diameter of the copper or stainless steel pipes carrying the CO2 significantly reduces material costs and ceiling load.
3. Utilize condenser heat recovery: Produce free 60°C hot water.
In traditional industrial refrigeration systems, all the heat released from the refrigerant compression process is discharged into the atmosphere through cooling towers or evaporative condensers. Meanwhile, seafood processing plants, slaughterhouses, and food processing facilities have to spend hundreds of millions of dong on diesel fuel or electricity to power boilers producing hot water at 55°C – 65°C for tray washing, CIP pipeline cleaning, and factory disinfection.
Solution Desuperheater & Condenser Heat Recovery This is enabled by Tan Long's integration:
- Install a welded plate heat exchanger or high-pressure tube bundle heat exchanger immediately after the compressor discharge end.
- It absorbs the superheat from the hot gas stream before it enters the condenser.
- Heats the water supply from 25°C to 60°C – 65°C completely continuously and automatically.
- Double economic benefits: Reducing fuel costs for heating water used in industrial cleaning by 100% simultaneously lowers the condenser inlet temperature, reduces fan/cooling pump power, and extends the lifespan of the compressor unit.
The high-efficiency evaporative condenser system with stable compression pressure control and heat recovery is used in AJ Total cold storage.
4. Digital Transformation & Energy Optimization: SCADA combined with VFD (Variable Frequency Drive)
Beyond simply selecting the refrigerant, next-generation cold storage technology demands seamless coordination between precision engineering and intelligent control:
- Central variable frequency drive (VFD) for screw compressors: Instead of adjusting the load using mechanical slide valves, which cause friction losses and reduce motor efficiency when running at low load, Tan Long integrates a frequency inverter to control the motor's rotational speed from 30Hz to 60Hz. When the cooling load demand decreases at night, the compressor automatically lowers its frequency, saving energy. 18% to 25% power compared to traditional methods.
- Intelligent electronic throttle valve (EEV): Continuously measuring superheat with a delay of less than 1 second, maintaining the evaporator superheat at an optimal level of 3K – 5K, maximizing wet heat exchange area without fear of refrigerant flooding the compressor.
- SCADA/IoT monitoring system: Collects voltage, current, and suction/discharge pressure data, automatically generates real-time energy efficiency performance (COP) reports, and provides early refrigerant leak warnings via a mobile application.
🌱 Financial advantages of achieving Green Building (ESG) certification for businesses:
Seafood and food export businesses using Freon-free green conversion refrigeration systems can easily obtain export certifications to European markets (EU Green Deal), the US, and access export packages. Green Credit with preferential interest rates from international banks such as IFC, ADB, and Vietcombank.
👉 Learn more: Energy-efficient refrigeration system design solutions based on ESG standards. | Consulting Engineer: 0933 357 058
5. Tan Long Refrigeration and Electrical Engineering – Pioneering green refrigeration conversion solutions in Vietnam
With a focus on sustainable development and mastering the most advanced refrigeration technology, Tan Long Refrigeration and Electrical Engineering Joint Stock Company Large-scale refrigeration projects using NH3 refrigerant and energy-saving technology have been and are being implemented in Vietnam:
- The main contractor for the Mycom NH3 refrigeration compressor station with a capacity of tens of thousands of kW at the NECS cold storage facility (102,642 pallets) is Mycom NH3.
- Design of an automated ultra-low temperature refrigeration system (ASRS) at AJ Total Long Hau.
- Consulting and installing IQF freezing systems, blast freezers, and storage warehouses for major corporations: KIDO, Vinh Hoan, Frescol Tuna, CP Group.
Is your business planning to invest in new cold storage or upgrade your compressor station to reduce electricity costs and meet the Net Zero target? Contact us today! Tan Long Refrigeration and Electrical Engineering To receive a return on investment (ROI) analysis report and the most optimal technical solutions.
Is your business in need of a survey, upgrade, or new design for your industrial refrigeration system?
With over 18 years of practical experience leading more than 29 major national projects, Tan Long's team of HVAC engineers is committed to providing accurate thermal load calculations, optimizing the COP efficiency coefficient, switching between natural refrigerants NH3/CO2, and saving 20–30% in operating electricity costs.
Engineer Nguyen Toan Thinh (Technical Director)
With over 18 years of practical experience in directing, consulting, designing, and constructing heavy industrial refrigeration systems, ASRS automated warehouses, and IQF freezing systems across more than 29 major national projects.
