Industrial refrigeration system (industrial refrigeration system) is an assembly of thermal and mechanical equipment working on a closed vapour compression cycle, drawing heat out of the space to be cooled and rejecting it to the environment, holding temperatures from +15°C down to −45°C depending on the application. The system has four main items connected by pipework carrying the refrigerant: compressor, condenser, expansion valve and evaporator.
In practice at seafood plants, cold stores and blast freezing rooms, an industrial refrigeration system differs fundamentally from domestic air conditioning in three ways: cooling capacity (from 50 kW to more than 5,000 kW), the refrigerant used (NH3 or CO2 rather than domestic Freon), and the requirement to run 24/7 for years without interruption.
This article analyses the construction of each item, the principle of the vapour compression cycle, classification by refrigerant, applications by sector and the design standards applied in Vietnam. Tân Long draws on more than 20 years designing and building hundreds of projects directly, from a 200 MT cold store for a medium-sized business to a 12,000 MT NH3 system for a seafood exporter.
An industrial refrigeration system is technical equipment that creates and maintains an environment colder than its surroundings, for storing, processing or transporting goods at industrial scale. Other names for it: industrial cooling system, industrial refrigeration plant, industrial evaporator system.
The clearest differences from domestic refrigeration lie in four technical criteria:
| Criteria | Domestic refrigeration | Industrial refrigeration system |
|---|---|---|
| Cooling capacity | 1-20 kW | 50-5,000+ kW |
| Refrigerant | R32, R410A, R22 | NH3 (R717), R404A, R507A, CO2 (R744) |
| Operating temperature | +5°C to +18°C | −45°C to +15°C |
| Operating mode | Intermittent, cycling on a thermostat | Continuous 24/7, automated by PLC/SCADA |
In practice, the line between "commercial" and "industrial" is drawn at 50 kW (about 14 tons of refrigeration per hour, or 172,000 BTU/h) and above. Most seafood plants, cold logistics operators and food processors in Vietnam run systems from 200 kW to 2,000 kW, squarely in the industrial group.
Operating principle of refrigeration system in some industrial equipment
An industrial refrigeration system works on the vapour compression cycle, in which the refrigerant changes continuously between liquid and vapour to absorb and reject heat under the second law of thermodynamics. The cycle has four consecutive processes in a closed loop.
The vapour compression cycle: four thermodynamic processes:
- Process 1: Compression: The compressor draws refrigerant vapour from the evaporator at low pressure (about 1–3 bar absolute for NH3 at −25°C) and compresses it to high pressure (10–18 bar). The vapour temperature rises to 80–120°C after compression. This is the only process in the cycle that consumes electricity.
- Process 2: Condensation: High-pressure refrigerant vapour enters the condenser, gives off heat to water or air and changes from vapour to liquid at the condensing temperature (typically 35–45°C in southern Vietnam’s climate). The heat rejected at this step equals the heat absorbed from the cold store plus the compressor work.
- Process 3: Expansion: Liquid refrigerant passes through the expansion valve and the pressure drops sharply from high to low. The temperature falls steeply under the Joule-Thomson principle, bringing the refrigerant to a low-temperature liquid-vapour mixture (for example −30°C for a freezer store).
- Process 4: Evaporation: The liquid-vapour refrigerant in the evaporator absorbs heat from the air or the product being cooled, evaporates fully and returns to the compressor, completing the cycle. This is the process that actually produces the cooling effect.
The efficiency of the whole cycle is measured by COP (coefficient of performance): COP = cooling capacity (kW) / electrical power consumed (kW). A well-designed industrial NH3 system achieves a COP of 3.5 to 5.0, meaning every 1 kWh of electricity produces 3.5–5 kWh of cooling. That is 20–35% higher than a Freon system of the same capacity, based on actual operating data Tân Long has collected from its projects.
The construction of an industrial refrigeration system
A complete industrial refrigeration system has five main groups of equipment, each performing a specific thermodynamic function in the cycle.
Compressor
The compressor is the only item in the cycle that consumes electricity, accounting for 60–75% of the system’s total power use. In industrial refrigeration in Vietnam there are three common types: screw compressors, reciprocating (piston) compressors and centrifugal compressors.
Screw compressors have taken more than 80% of the market in new industrial NH3 systems installed since 2015, thanks to quiet, durable operation (40,000–60,000 hours between overhauls) and continuous capacity control from 25% to 100% through a slide valve. Tân Long supplies screw compressor packs from established manufacturers such as Bitzer (Germany), Mycom (Japan) and Hanbell (Taiwan), from 50 kW upwards.
Condenser
The condenser rejects heat from the refrigerant to the outside, and works best the further the condensing temperature sits below ambient. In southern Vietnam’s climate, with dry bulb temperatures of 32–38°C and high humidity, an evaporative condenser (evaporative condenser) is the best choice, because the latent heat of evaporating water brings the condensing temperature down to 35–38°C, 8–12°C lower than an air-cooled condenser.
That 8°C difference in condensing temperature equates to 15–20% less compressor electricity, based on calculations from the 5,000 MT cold storage project Tân Long delivered for Frescol Tuna Vietnam Co., Ltd in Nghệ An.
Evaporator
The evaporator (also called the cooling unit) absorbs heat from the storage space and is the item that directly creates the low-temperature environment the product sits in. In cold and freezer stores the most common type is the condenser ceiling-mounted forced-air unit cooler, built from copper or aluminium heat exchange tube with aluminium fins.
For freezer stores from −18°C to −25°C, the evaporator needs defrosting 2–4 times a day to clear the ice building up on the heat exchange surface. Whether electric defrost or hot gas defrost is used directly affects running costs and the temperature swing in the store, and has to be settled at the design stage.
Expansion valve and pressure vessels
The expansion valve controls the flow of refrigerant into the evaporator — an electronic expansion valve (EEV) in modern systems, or a thermostatic expansion valve (TEV/TXV) in traditional ones. An EEV with a PLC controller allows control to ±0.1°C, matching HACCP requirements for stores holding food for export.
Pressure vessel (pressure vessels) comprise the high-pressure receiver, the low-pressure receiver and the liquid separator, ensuring enough refrigerant is held and protecting the compressor from liquid slugging, which damages the valves.
PLC and SCADA control panels: the brain of the system
A modern industrial refrigeration system integrates a PLC control cabinet (programmable logic controller) to automate the whole operating cycle: starting and stopping the compressor with the cooling load, adjusting the expansion valve, controlling defrost, and alarming on pressure and temperature faults. A SCADA system (supervisory control and data acquisition) allows remote monitoring over the internet, logging operating data continuously for HACCP checks and energy performance analysis.
Industrial refrigeration systems classified by refrigerant
Refrigerant is a crucial factor determining the performance, investment cost, safety requirements, and lifespan of the entire system. In Vietnam today, there are three common groups of refrigerants used in industry.
| Comparison criteria | NH3 (R717) | HFC (R404A/R507A) | CO2 (R744) |
|---|---|---|---|
| COP efficiency | Highest (3.5–5.0) | Moderate (2.5–3.5) | High at low temperature |
| Refrigerant cost | Lowest (20,000–40,000 VND/kg) | High (600,000-1,200,000 VND/kg) | Medium |
| GWP (global warming potential) | 0 | 3.922 (R404A) | 1 |
| Toxicity | Toxic (IDLH 300 ppm) | Non-toxic | Asphyxiant at high concentration |
| Common application in Vietnam | Cold stores >500 MT, seafood plants | Cold stores <500 MT, supermarkets | Expanding since 2022 |
| Safety requirements | Separate machine room, NH3 sensors, fire protection | Lower | CO2 sensors, ventilation |
NH3 systems accounts for more than 70% of total industrial cold storage capacity in Vietnam, particularly in seafood exports, because of its low running costs and high efficiency between −18°C and −40°C. Every major project Tân Long has delivered — Kyokuyo Vina Foods, Lotte F&G Vietnam, C.P. Vietnam Livestock Corporation — uses an NH3 system.
Freon (HFC) systems suit small and medium stores under 500 MT, where initial capital cost matters more than long-term running costs. HFCs are, however, being phased down under the Kigali Amendment (which Vietnam signed in 2019), with HFC consumption expected to fall 80% by 2045.
CO2 (R744) systems have been applied at some supermarket chains and new cold stores since 2022, suiting the sustainability requirements of the cold chain under EU export standards in particular.
Industrial refrigeration in food, seafood and logistics
Industrial refrigeration directly serves four key sectors of Vietnam’s economy, each with its own technical requirements.
- Cold storage for seafood and frozen food runs at −18°C to −25°C, to the international standard of the Codex Alimentarius and FDA/EU requirements for export goods. The cooling load is calculated as Q = m × Cp × ΔT plus the load through the walls (W/m²), with 100 mm to 200 mm PU foam panels as the main insulation. Industrial cold storage Tân Long designs to HACCP and in line with the requirements of bodies such as BRC and SQF.
- Blast freezing rooms and air blast tunnels run at −35°C to −45°C, freezing product from ambient down to −18°C in 4–6 hours (blast freezing) or faster with a high-capacity air blast freezer . The speed of freezing directly affects product quality: fast freezing (under 30 minutes) forms small ice crystals and preserves the cell structure far better than slow freezing.
- IQF (individual quick freezing) lines are the most technically advanced application in the food cold chain, freezing each individual item (shrimp, fish fillets, fruit and vegetables) in 8–25 minutes at −35°C to −40°C. Tân Long has manufactured mesh belt IQF freezer Since 2011, the capacities have been 500, 750, and 1,000 kg/h per unit; large factories combine multiple units (Kyokuyo Vina Foods: 8 units, total 4,300 kg/h), serving exports to Japan, South Korea, and the EU.
- Cold chain logistics requires a refrigeration system holding a steady temperature through transport and storage, keeping the cold chain unbroken. Cold store capacities run from 500 MT to 10,000 MT, designed for daily inbound and outbound movements of 5–10% of total volume.
Refrigeration system design standards: ASHRAE, HACCP and Vietnamese regulations
Industrial refrigeration in Vietnam complies with both international standards and domestic regulations, particularly at food processing plants serving exports.
- ASHRAE Standard 15-2022 (Safety Standard for Refrigeration Systems) sets the safety requirements for industrial refrigeration: minimum machine room area, ventilation rate by refrigerant concentration, leak detection, pressure relief valves and emergency start/stop procedures. This standard is the design basis for every NH3 system Tân Long builds.
- HACCP (Hazard Analysis Critical Control Points) under the Codex Alimentarius requires the refrigeration system to hold temperature within ±1°C of design, to log temperature data continuously (at least every 15 minutes) and to alarm when temperature goes outside limits. Tân Long SCADA panels include logging and temperature reporting in the formats required by FDA, EU and FSANZ inspectors.
- Decree 44/2016/ND-CP (occupational safety for machinery, equipment and materials subject to strict safety requirements) and TCVN 8366:2010 (pressure vessels – technical requirements) apply to every pressure vessel in an NH3 or CO2 system. The equipment has to be inspected by a body licensed by the Ministry of Labour, Invalids and Social Affairs before it is put into use.
- QCVN 11-1:2012/BKHCN (national technical regulation on the safety of food and beverages) and the rules of the Food Safety Authority apply to cold stores holding food for retail and export.
The cost of an industrial refrigeration system: reference figures
The cost of an industrial refrigeration system depends on store volume, operating temperature, refrigerant and level of automation. Below is an indicative price range from actual Tân Long project data for 2022–2024.
| Warehouse size | Temperature | System type | Refrigeration equipment cost (indicative) |
|---|---|---|---|
| 200-500 MT | 0°C to −5°C (chill room) | Freon R404A | 1.5–4 billion VND |
| 200-500 MT | −18°C to −25°C (freezer room) | NH3 or Freon | 3–8 billion VND |
| 500-2,000 MT | -18°C to -25°C | NH3 | 8–25 billion VND |
| 2,000-10,000 MT | -18°C to -40°C | NH3 | 25–120 billion VND |
These figures exclude insulated panels, the store floor, machine room construction and the incoming electrical supply. Total cold store investment is usually 2.5–3.5 times the cost of the refrigeration system alone. For an accurate quotation, Tân Long carries out a free site survey and calculates the cooling load to the ASHRAE Handbook — Refrigeration.
Tân Long: 20 years designing and building industrial refrigeration systems
Tân Long Refrigeration Electromechanical Joint Stock Company was founded in 2005 and specialises in consulting, designing and building industrial refrigeration systems for food and seafood plants and cold logistics nationwide. Our engineering team has more than 20 years of direct experience, on projects from 50 kW up to NH3 systems over 2,000 kW.
Some flagship Tân Long projects: a 12,000 MT NH3 cold store for Frescol Tuna Vietnam Co., Ltd in Nghệ An (6 blast freezing tunnels, 2 screw compressors, 2 condensers), a complete NH3 refrigeration system for Kyokuyo Vina Foods Co., Ltd (8 high-speed IQF lines, contact freezers, flake ice machines), and cold and freezer storage for Lotte F&G Vietnam Co., Ltd at Long Hau Industrial Park, Tây Ninh.
Tân Long has its own equipment factory in Duc Hoa 1 Industrial Park, Tây Ninh, giving control over quality from fabrication through to installation. HACCP and ISO 9001 certification applies to the whole process from design and manufacture to project handover.
For advice on the refrigeration system that suits your scale and sector, contact the Tân Long engineering team on the hotline (+84) 933 357 058 (Mr. Thinh) or (+84) 982 330 357 (Mr. Sang). Tân Long carries out a site survey and gives advice free of charge before quoting.
Frequently asked questions about industrial refrigeration systems
What is industrial refrigeration system?
An industrial refrigeration system is an assembly of thermal and mechanical equipment working on the vapour compression cycle, holding temperatures from +15°C down to −45°C for food storage, seafood processing and cold logistics at industrial scale (from 50 kW upwards). It has four main items: compressor, condenser, expansion valve and evaporator, connected by refrigerant pipework.
How do NH3 and Freon refrigeration systems differ?
NH3 (ammonia, R717) has a COP 20–35% higher than Freon R404A and costs 90% less as a refrigerant, suiting large stores of 500 MT and above at temperatures from −18°C to −40°C. Freon is simpler from a safety point of view and suits smaller stores under 500 MT. HFC Freons are, however, being phased down under the Kigali Amendment, which Vietnam has committed to.
What does an industrial refrigeration system cost to install?
A refrigeration system for a 200–500 MT freezer store at −18°C to −25°C runs from 3–8 billion VND depending on refrigerant and automation. A 500–2,000 MT cold store on NH3 runs from 8–25 billion VND. The actual cost depends on the cooling load survey, location and HACCP requirements. Tân Long quotes free of charge after a site survey.
What scheduled maintenance does an industrial refrigeration system need?
An NH3 system needs maintenance every 3–6 months: check pressure and refrigerant charge, clean the condenser and evaporator (which directly affects COP), check the compressor oil, and check safety valves and NH3 leak sensors. Maintaining to schedule extends compressor life by 30–50% and keeps the COP at design level.
Which standards apply to refrigeration for an export food store?
Food stores exporting to the EU, Japan and the United States need to meet HACCP (Codex Alimentarius), hold temperature to ±1°C and log continuously. On technical safety: ASHRAE Standard 15, TCVN 8366:2010 (pressure vessels) and Decree 44/2016/ND-CP. Tân Long helps businesses design the system and complete the HACCP, BRC and SQF certification documentation from the construction stage onwards.
Does Tân Long build refrigeration systems nationwide?
Yes. Tân Long designs, supplies equipment for and builds refrigeration systems nationwide, from the south (Ho Chi Minh City, Tây Ninh, Tiền Giang, Cà Mau, Sóc Trăng) through central Vietnam (Nghệ An) to the north. Head office at 86 Dong Den, Tan Binh, Ho Chi Minh City. Equipment factory in Duc Hoa 1 Industrial Park, Tây Ninh.
NH3 or CO2 for a new cold store?
NH3 remains the best choice for a new industrial cold store in Vietnam on both capital and running costs. CO2 suits a business that needs green certification or is exporting to the EU with low carbon footprint requirements. The final decision depends on the scale, location, budget and certification requirements of each specific project.
Frequently asked questions about refrigeration systems
What is a refrigeration system?
A refrigeration system is an assembly of equipment working on the vapour compression cycle — compressor, condenser, expansion valve and evaporator — whose job is to take heat out of the space or product being cooled and reject it to the environment.
How does an industrial refrigeration system differ from domestic refrigeration?
Domestic refrigeration means packaged appliances such as refrigerators and household air conditioners. An industrial refrigeration system is designed specifically for the heat load of each project, built on site and run continuously at a far larger scale.
What equipment makes up an industrial refrigeration system?
The four main items are the compressor, condenser, expansion valve and evaporator. Alongside them are receivers, liquid separators, pressure vessels, pipework, the control panel and the safety systems.
Which industries need industrial refrigeration?
Seafood, meat, dairy, beer and soft drinks processing, pharmaceuticals, cold storage logistics, post-harvest produce, and many other industries needing temperature control during processing or storage.
What does Tân Long provide for a refrigeration system?
Tân Long provides consulting, design, pressure equipment manufacture, installation and maintenance of industrial refrigeration systems as a complete package for plants and cold stores.
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