Glycol water cooling is a mixture of glycol (propylene glycol or ethylene glycol) and purified water used as the intermediate heat transfer fluid in an indirect cooling system (secondary refrigerant system). It replaces pure water in applications requiring temperatures below 4°C (39°F), because water would freeze and destroy the pipework, pumps and heat exchangers.
What is glycol chilled water? How does glycol chilled water work?
Glycol water cooling (also called brine coolant) is the important secondary coolant in modern two-loop cooling cycles. In this system, the refrigeration compressor cools the glycol solution down to the required temperature right at the evaporator vessel.
A circulation pump system then carries the cooled glycol chilled water to the consumption points such as the IQF belt freezer, product immersion tanks or plate heat exchangers. There the solution absorbs heat from the food or the space being cooled, then returns to the evaporator vessel to start a new cooling cycle.
Using a closed circulation loop with glycol chilled water completely separates the primary refrigerant (such as NH₃ or HFC) from the direct processing area. This is the optimal engineering solution and a mandatory requirement in cold storage design solutions meeting international standards such as HACCP, BRC and IFS. It ensures cooling performance and also removes the risk of contamination from NH₃ (which is extremely dangerous at 25 ppm), protecting both food safety and worker health at the plant.
How to determine the right glycol chilled water mix ratio for each application
Determining the mix ratio between glycol chilled water and purified water is critical: it directly determines the freezing point, the corrosion resistance and the heat transfer performance of the whole system. Tan Long always advises a ratio based on the actual operating temperature of each plant, to balance technical safety against operating cost.
Below is the specification table for Propylene Glycol (PG) – the food-safe solution Tan Long recommends for food cold storage and processing systems:
Glycol chilled water concentration reference table:
| PG / water ratio (% by volume) | Freezing point | Boiling point | Typical applications |
| 20% / 80% | -8°C | 102°C | Light industrial air conditioning |
| 30% / 70% | -14°C | 103°C | Water-cooled chillers for pharmaceuticals and beverages |
| 40% / 60% | -24°C | 104°C | Seafood processing, IQF belt freezer systems |
| 50% / 50% | -33°C | 106°C | Deep refrigeration systems, sub-zero below -25°C |
| 60% / 40% | -52°C | 108°C | Special industrial refrigeration, biological product storage |
Generally, a concentration of glycol chilled water at the level 40/60 is considered the sweet spot for industrial refrigeration systems in Vietnam. It protects the equipment against pipes cracking from freezing while keeping viscosity moderate so the refrigeration compressors and circulation pumps run steadily.
If the PG concentration goes above 50%, the viscosity of the solution rises very quickly, causing high pressure losses and significantly increasing the electricity the pump system consumes. Running at the wrong ratio can also affect the durability of the protection devices in the control cabinet because of sudden current increases.
Propylene glycol or ethylene glycol: which suits food processing?
The two common glycols in industrial refrigeration systems are propylene glycol (PG) and ethylene glycol (EG). The choice depends directly on food safety standards and the required operating temperature.
| Criteria | Propylene glycol (PG) | Ethylene glycol (EG) |
|---|---|---|
| Toxicity | Low, FDA recognised as food safe (GRAS) | Moderately toxic, not for food contact |
| Freezing point (50% in water) | -33°C (-27°F) | -37°C (-35°F) |
| Kinematic viscosity (at -10°C) | ~35 cSt | ~15 cSt |
| Thermal conductivity | About 10–15% lower than EG | Higher, better heat transfer performance |
| Application | Food, seafood, beverages, pharmaceuticals | HVAC, equipment cooling with no food contact |
| Expense | About 20–30% higher than EG | Lower |
Tan Long supplies food-grade propylene glycol for every processing plant project. Ethylene glycol is specified only for HVAC systems and equipment cooling with no risk of contact with food or staff.
Why does a glycol chilled water solution need a corrosion inhibitor?
A glycol chilled water solution in its pure state is usually slightly acidic. Over time, under the effect of dissolved oxygen or high operating temperature (particularly above 60°C), it oxidises and breaks down into organic acids such as glycolic, glyoxylic and oxalic acid. The build-up of these acids lowers the pH, turning the coolant into an agent that attacks the metal surfaces of the pumps, pipework, pressure vessel and the heat exchangers.
To protect the system, an industrial-standard glycol chilled water solution must include a corrosion inhibitor package. Compounds such as sodium molybdate, tolyltriazole (TTZ), sodium nitrate and borax are blended at tightly controlled concentrations to form an extremely thin passive film on the surface of carbon steel, stainless steel, brass and aluminium. For these inhibitors to work optimally, the pH of the solution must be held steadily in the safe range of 7.5 – 8.5.
Tan Long currently supplies a glycol chilled water pre-mixed product line using organic acid technology (OAT) that meets ASTM D3306 and D6210 strictly. This solution is compatible with modern water chiller systems and extends the service life of the fluid to 3–5 years. To keep the system running reliably, the Tan Long technical team is always ready to help customers check the pH and the glycol concentration every 6 months, preventing corrosion and equipment damage early.
What does a complete glycol chilled water system include?
A system glycol chilled water to standard, designed and delivered turnkey by the Tan Long engineering team, comprises 6 core equipment groups running in a strictly closed cycle:
- Refrigeration compressor unit: This is the heart of the whole system. Tan Long uses screw or piston refrigeration compressors from specialist global brands, running NH₃ or HFC with a flexible capacity range from 5 kW to over 500 kW. The compressor units are assembled by Tan Long directly at the Duc Hoa 1 Industrial Park plant, ensuring strict output quality control.
- Dedicated evaporator vessel: This is where the main heat exchange takes place to produce the glycol chilled water. Tan Long prefers the shell-and-tube type or a plate heat exchanger (PHE) in 316L stainless steel. This material ensures hygiene and does not introduce lead or heavy metal ions into the solution in food industry applications.
- Glycol buffer tank: With a capacity of 500 – 5,000 litres in 304/316 stainless steel, the buffer tank keeps the glycol chilled water temperature stable. A 50 – 100 mm polyurethane insulation layer minimises heat loss, even when the compressor pauses between cycles.
- Inverter-driven circulation pump system: To carry the glycol chilled water solution to the consumption points such as the mesh belt IQF freezer, Tan Long fits a pump system with an integrated inverter. This technology adjusts the flow to the actual load, saving the business 20 – 35% of electricity compared with fixed-speed pumps.
- Pipework network and fittings: The distribution pipework (carbon steel or stainless steel) is carefully insulated. At each branch, Tan Long fits a hydraulic balancing valve so the pressure of the glycol chilled water is even at every point in the plant.
- Smart control panel: The whole operation is monitored by a PLC control cabinet or a SCADA system. The system allows temperature, pressure and flow to be followed in real time and automatically sends an alert by SMS or email if the solution temperature drifts outside the ±1°C setpoint band.
Investing in a system glycol chilled water matched from design through to installation at Tan Long not only optimises cooling performance but also ensures the highest durability and safety for cold storage design industrial.
Tan Long glycol chilled water system specifications
To ensure the highest operating performance, the glycol chilled water systems Tan Long designs comply with strict specification ranges. Below is a summary of the standard figures for easy reference on your project:
| Parameter | Standard range | Note |
|---|---|---|
| Cooling capacity | 5 kW – 500+ kW (1,4 – 142+ TR) | Designed to the actual load |
| Glycol temperature leaving the evaporator | -10°C to +5°C (14°F – 41°F) | Can go down to -25°C (-13°F) |
| Standard mix ratio | 40% PG / 60% water | Adjusted to the operating temperature |
| Solution freezing point | -24°C (-11°F) at 40/60 | Protects the system on a sudden shutdown |
| Solution pH | 7,5 – 8,5 | Checked every 6 months with a pH meter |
| Primary refrigerant | NH₃ (R717) or HFC | NH₃ for large capacities above 100 kW |
| Compressor | Screw or piston | Manufactured in-house in Tay Ninh |
| Evaporator vessel | Shell-and-tube or PHE | 316L stainless steel for food applications |
| Glycol buffer tank | 500 – 5,000 litres | 304/316 stainless steel, polyurethane insulated |
| Control | PLC / SCADA | Remote monitoring, ±1°C alarm |
| Power supply | 3 pha, 380V – 415V, 50 Hz | Vietnamese grid standard |
| Certification | HACCP, ISO 9001 | Meets importer inspection requirements |
Installing a glycol chilled water to technical standards does not stop at the figures in the table above. Tan Long combines optimal design with more than 20 years of refrigeration system installation experience to deliver the most durable solution.
All the critical parts, from the refrigeration compressors to the pressure vessels, are strictly quality controlled before despatch. This coordination keeps the glycol chilled water circulating steadily, protects the evaporators from freezing up and lets the business produce with no worry about sudden equipment failure.
Glycol chilled water system compared with an ordinary water chiller
Although both the glycol chilled water (glycol chiller) and the ordinary water chiller work on the principle of indirect cooling, they are designed for completely different temperature ranges and technical requirements. Choosing the wrong type can waste electricity or cause serious equipment damage.
Ordinary water chiller
This system works best between 7°C and 12°C, which suits industrial air conditioning, plastic mould cooling and production processes needing a stable above-zero temperature. However, once the requirement drops below 4°C, pure water risks freezing in the pipework, cracking the evaporator vessel and destroying the pump and the control valves.
Glycol chilled water system (glycol chiller)
This is the answer for deep cooling problems. By using a glycol chilled watersolution, the system can lower the freezing point to -24°C (at a 40/60 mix) or even further without changing the core configuration of the refrigeration compressors.
In Vietnam, particularly in seafood processing and frozen food, a glycol chilled water system is essential for equipment such as:
- Rapid chilling tanks.
- Spray systems on IQF belt freezers.
- Fermentation temperature control systems in breweries and dairies.
Because the operating temperature is usually held between -5°C and -15°C, using a water chiller with glycol keeps the solution liquid, so heat exchange continues safely and without interruption.
Real applications of the glycol chilled water system
Currently, the system glycol chilled water is the backbone of the industrial cold chain in Vietnam, serving a wide range of production stages with demanding temperature and food hygiene requirements.
- Seafood & food processing: A glycol chilled water solution is carried to preparation immersion tanks for rapid chilling, or fed to glycol spray lines so that products leaving the IQF belt freezer reach a core temperature below -18°C. The system also cools washing conveyors and feeds the seafood cold storage.
- Brewing and beverages: The system controls fermentation temperature precisely between 8°C and 15°C. Holding the temperature steady with glycol chilled water stops enzymes working outside their range, keeping flavour and product quality consistent.
- Pharmaceuticals and healthcare:Water chillers use glycol to hold cleanroom temperatures and reaction equipment at 2°C – 8°C, meeting GMP and GSP standards strictly for biological product storage.
Representative Tan Long projects: With professional design and delivery capability, Tan Long has successfully delivered glycol chilled water systems for many major partners such as: Kyokuyo Vina Foods, Lotte F&G Vietnam, C.P. Vietnam, Frescol Tuna Vietnam, along with numerous projects in seafood centres such as Ca Mau, Soc Trang and Nghe An.
Running the system together with high-efficiency refrigeration compressors and an intelligent PLC control cabinet has helped these businesses optimise operating cost and strengthen their competitiveness in international markets.
How to maintain a glycol chilled water solution so the system lasts
A glycol chilled water solution does not last forever. Its quality degrades over time through three main agents: dissolved oxygen entering through the valves, high operating temperature depleting the corrosion inhibitors, and bacterial growth once the pH falls below neutral.
To ensure optimal heat transfer for the water chiller, the Tan Long technical team recommends a standard glycol chilled water maintenance routine in 3 periodic steps:
- Check the glycol concentration (every 6 months): Use a dedicated refractometer to measure the refractive index of the solution. This confirms the mix ratio between water and glycol chilled water still matches the original design, avoiding the risk of freezing that would puncture the industrial evaporator.
- Monitor the pH: Use a pH meter to keep it in the safe range of 7,5 – 8,5. If the pH falls below 7, organic acids attack the metal surfaces of the refrigeration compressors and the pipework. At that point an alkalising additive package must be added, or the solution replaced.
- Replace the solution periodically: Sau 3 – 5 years of operation, the glycol chilled watersolution should be replaced completely. Before the new fluid is charged, the whole system including the pressure vessels and the pipework must be flushed clean to remove accumulated sludge and rust.
Currently, Tan Long offers a package service to check and replace the glycol chilled water under a full maintenance contract. Tan Long supplies not only a compliant solution but also a detailed analysis report and technical recommendations after each check, so the business can run its cold storage design reliably and efficiently.
Tan Long – A reputable and authorized provider of Glycol water cooling solutions.
Tan Long Refrigeration and Electrical Engineering Joint Stock Company is a pioneer with nearly 20 years of specialist experience in consulting, designing and installing industrial refrigeration systems in Vietnam. Tan Long understands that running a Glycol water cooling demands technical precision to ensure optimal performance and save electricity for the business. With thousands of projects delivered successfully, Tan Long commits to a turnkey solution that meets every demanding customer requirement.
When you trust and choose our machine installation service Glycol water cooling at Tan Long, you receive the following:
- Genuine imported equipment: All the components that make up the system, from the lines refrigeration compressor high performance to various types industrial refrigeration Modern and imported directly from reputable brands, ensuring durability and stability.
- In-depth consulting solutions: Experienced Tan Long engineers survey the site to advise on the machine capacity Glycol water cooling most suitable, in combination with the process cold storage design consulting A systematic approach aimed at optimizing initial investment costs for businesses.
- Professional construction process: Tan Long possesses the capability to provide a complete package, from system design to implementation. water chiller Using Glycol solution during installation and operation ensures the system runs continuously 24/7.
- Dedicated after-sales service policy: Tan Long commits to the most competitive price on the market together with a long warranty and periodic maintenance, so the customer can run the system with confidence Glycol water cooling.
Don't hesitate to contact us! Tan Long for advice from specialists and to own a Glycol water cooling Technically sound and offered at the most competitive prices. For product details and price quotes, please contact us via hotline: (+84) 933 357 058 or email: info@tanlongvn.com for quick support.
The equipment matching this solution: industrial glycol water chiller.
Frequently asked questions about glycol chilled water
Is a 40/60 mix suitable for Vietnamese conditions?
Yes. The -24°C (-11°F) freezing point of a PG 40/60 solution is below the lowest operating temperature in cold store and food chiller systems in Vietnam (usually -10°C to -15°C). This ratio stays safe even if the compressor stops suddenly and the solution temperature changes temporarily.
Does glycol contaminate food if it leaks?
Food-grade propylene glycol (food-grade PG) is recognised by the FDA as safe (GRAS). Even so, double-wall pipe design and an automatic leak detection system remain mandatory standards in every project Tan Long installs for a HACCP-certified plant.
How do you know when the glycol solution needs replacing?
The three clearest signs are a pH below 7 (the solution has acidified), the colour turning dark brown or cloudy (a sign of oxidation and microbial growth), and a glycol concentration measured by refractometer more than 5% below the design ratio (through leakage or unreplaced water evaporation).
Does Tan Long supply the glycol solution on its own?
Yes. Tan Long supplies food-grade propylene glycol (food-grade PG) pre-mixed at 40/60 with an OAT corrosion inhibitor package, in 200-litre drums or to order, delivered to plants nationwide.
Which industries use glycol chilled water systems?
Below are the industry groups in which Tan Long has installed the most glycol chilled water systems:
- Seafood processing: fish fillets, shrimp, squid and frozen export products.
- Food and meat processing: carcass meat, cut meat and ready-prepared foods.
- Dairy and soft drinks: lines that need stable cooling throughout the production shift.
- Pharmaceuticals and healthcare: GSP warehouses and products requiring strict temperature control.
Each sector has different requirements for temperature range, contact materials and capacity. Please contact Tan Long's engineering team for advice on the right configuration for your products.
Technical standards applied to glycol chilled water systems
Equipment supplied by Tan Long is manufactured to the following standards and material requirements:
- HACCP
- FDA
- ISO
- polyurethane insulation
- NH3 refrigerant
Depending on each project's requirements, the engineering team will advise on the material configuration and connection standards that best suit the plant's existing system.
The glycol chilled water system consulting and supply process at Tan Long
Tan Long controls both design and manufacture at its plant in Duc Hoa 1 Industrial Park, Tay Ninh (formerly Long An), so the investor deals with a single point of contact from survey to handover:
- Survey and requirement definition: engineers work directly at the plant to establish capacity, layout, refrigerant and real operating conditions.
- Technical proposal: calculating a suitable configuration and discussing it with the investor's technical team before it is fixed.
- Detailed design: drawings are prepared and materials and equipment selected to match the refrigerant and the operating temperature range.
- Manufacture and works testing: machining, assembly and a test run before the unit leaves the factory.
- Installation and acceptance: connection into the plant's system, load testing and handover with the technical documentation.
- Warranty and operating support: operating instructions for the plant's technical team and fault support during the warranty period.
Why choose Tan Long to supply your glycol chilled water system?
Tan Long is a refrigeration engineering joint stock company with more than 20 years in industrial refrigeration, serving seafood and food processing plants and large-scale cold stores across Vietnam.
- In-house manufacturing: its own factory in Duc Hoa 1 Industrial Park, Tay Ninh (formerly Long An), with no dependence on outside subcontractors.
- Turnkey D&B capability: design and construction under one roof, reducing the risk of a gap between the drawings and what is actually installed.
- Complete documentation: equipment is handed over with technical files and CO/CQ certificates of origin.
- Engineers with field experience: advice based on each plant's actual system configuration rather than selling from a catalogue.
- Support after handover: the technical team is on hand for operation and maintenance throughout the equipment's life.
For advice on a specific configuration, please contact Tan Long's engineering team or see the projects already delivered.
Request advice and a quotation
Tan Long designs and builds industrial refrigeration equipment at its plant in Duc Hoa 1 Industrial Park, Tay Ninh (formerly Long An), so capacity and dimensions can be adjusted to the actual site. Call 0933 357 058 (Mr. Thinh) or send a quotation request with your output per shift and your main product type.
Related technical reading
- Water chiller schematic diagram: details and technical standards
- What is a chiller? Structure and operating principle of the chiller system
- Industrial water chillers: Reliable installation quotes 2026
- Chiller cooling towers: The optimal solution for cold storage.
- Glycol Water Chiller
