Cold storage design is the engineering process of building a low-temperature storage room that controls temperature, humidity, airflow and insulation together for everything stored inside. A properly executed design establishes the actual heat load (kW), selects the compressor system, specifies insulated panels from 100 mm to 200 mm (4 to 8 inches) thick, and chooses doors suited to each type of product stored.
In Vietnam, industrial cold stores serve the supply chains for seafood, processed food, pharmaceuticals and agricultural exports. Operating temperatures fall into two main bands: chill rooms at 0°C to 10°C (32°F to 50°F) for fresh food, and freezer stores at −18°C to −25°C (−0.4°F to −13°F) for frozen goods. A 5°C error in the initial design increases electricity consumption by 15% to 20% across the store's entire operating life.
Tân Long Refrigeration Electromechanical JSC has designed and built industrial cold stores since 2005. With more than 300 completed projects from 100 MT to 12,000 MT, Tân Long provides a complete solution from technical drawings and domestically manufactured equipment through to construction.
This article sets out the design principles. For a survey and a proposal for your specific project, see our cold store design consultancy service or our turnkey cold store contracting service.
What is an industrial cold store?
An industrial cold store — also called cold storage or an industrial cold room — is a sealed engineered structure built to hold a stable low temperature for storing goods to demanding food or pharmaceutical standards. A standard cold storage design process focuses on three main groups of components: the insulated envelope using fire-retardant PU foam panels, the specialist refrigeration system such as refrigeration compressor combined with condenser, evaporative condenser and the automated control system built on PLC or SCADA technology.
An industrial cold store differs from a domestic freezer in the scale of its heat load and the requirement for continuous 24/7 operation. A small industrial cold room starts at 50 m² (538 ft²) with a heat load of around 15 kW, while a large logistics cold store runs to 5,000 m² to 20,000 m² (53,800 ft² to 215,000 ft²) with a multi-stage NH3 system.
The core objectives of cold store design are three: hold the temperature within ±0.5°C, reduce heat loss through the envelope to below 10% of the total heat load, and optimise the compressor's COP (coefficient of performance) to between 2.5 and 4.0.
Types of cold store and their standard temperature ranges
Classifying the system by operating temperature is the most important step in a professional cold storage design process. Temperature directly determines the technical parameters: the insulated panel thickness, the refrigerant and the compressor pack capacity calculation.
| Warehouse type | Operating temperature | Typical applications | Common refrigerants |
| Chill room (cool room) | 0°C to 10°C | Vegetables, cut flowers, vaccines, pharmaceuticals | R404A, R134a |
| Freezer room | -18°C to -25°C | Frozen seafood, meat, processed food | R404A, NH3 |
| Blast freezer | -35°C to -45°C | Seafood for export, IQF conveyors | NH3, CO2 cascade |
| Pre-cooling room | 10°C to 15°C | Pre-treatment before goods enter the storage room | R404A |
| Logistics cold store | −18°C to 5°C depending on the zone | Multi-temperature distribution centres | NH3, R744 (CO2) |
From Tân Long's practical experience in the major industrial parks, cold storage design projects for storing fresh food (chill rooms at 0°C to 5°C) currently account for around 60% of all projects in Vietnam.
For the frozen seafood export segment, which requires a stable −20°C, construction and installation must comply strictly with international standards. This is mandatory for processing plants targeting demanding markets such as the EU or Japan, to ensure food safety under HACCP certification. To streamline this, Tân Long normally advises clients to use a turnkey cold store solution, controlling everything from design through to operation in one package.
6 technical factors that determine a professional cold store design
A process cold storage design to standard depends entirely on six core input parameters. If any one is missing, the engineer cannot calculate the heat load accurately, leaving the compressor system either overloaded or oversized and wasting electricity.
Dimensions and storage capacity
The weight of goods (in tonnes, MT) and the store volume (m³) are the two parameters that determine the refrigeration capacity required (kW or BTU/h). For example, a cold storage design project for 200 MT of frozen seafood requires a refrigeration capacity of around 80 kW to 120 kW (273,000 BTU/h to 409,000 BTU/h), depending on the ambient temperature and the frequency of movements in and out.
Store height directly affects the usable floor area. A standard industrial cold store has a clear height of 5 m to 9 m (16 ft to 30 ft). Stores above 6 m need the additional heat load through the ceiling and temperature stratification factored into the air distribution design.
The characteristics of the product stored
Each product has different temperature, humidity and air circulation requirements. Frozen seafood needs −18°C to −22°C at 90% to 95% relative humidity. Vaccines and medical biologicals require a far narrower band: 2°C to 8°C (35.6°F to 46.4°F) with a tolerance no greater than ±0.5°C. Fresh produce also needs CO₂ and ethylene concentrations controlled to extend its storage life.
The design of the evaporators and the air distribution depends directly on these product characteristics. Get this wrong and the store develops cold spots and hot spots — the over-cold areas freezing product unnecessarily, the warmer areas causing localised spoilage.
The temperature of incoming product
The temperature of goods at intake (the pull-down load) is the largest single component of the heat load and must be dealt with thoroughly within the first 12 to 24 hours of operation. A typical technical example: one tonne of chicken entering the store at 15°C requires three times as much heat removal as product already pre-cooled to 0°C. The engineer must therefore calculate this parameter in detail right at the cold storage design stage, so the compressor pack runs steadily and is not overloaded on its first operating cycle.
From practical experience on the seafood processing plant projects Tân Long has delivered, the best solution is to install a pre-cooling room entirely separate from the main freezer store. The pre-cooling room takes on the job of bringing product rapidly from 20°C down to 0°C before it moves into frozen storage at −20°C. This technique relieves the direct pressure on the main system — an approach that marks out cold storage design done professionally, protecting the equipment and optimising the owner's electricity costs.
How the frequency of movements in and out affects operating performance
In the process cold storage design, the frequency of door openings is a variable that causes significant heat loss and needs the engineer's attention. Technically, each door opening lets 0.5 kW to 2 kW of heat into the store, depending on the door size and the temperature difference with the outside. For logistics cold stores with 20 to 30 movements a day in particular, the compressor system needs to be designed with at least 30% more spare capacity than a static storage room of the same size.
A standard cold storage design drawing calls for supporting equipment such as air curtains or dock shelters to minimise sudden heat ingress. The position and size of the insulated door system — whether electric sliding doors or hinged doors — is also an important matter to be worked out in coordination right at the start of the project, to ensure operations run as smoothly as possible.
How materials handling equipment affects the cold store design
Electric forklifts and manual pallet trucks moving inside the storage area generate significant heat from friction and from their electric motors. In a standard cold storage design the engineer must include this heat load in the total capacity of the refrigeration system, particularly in large stores where 3 to 5 forklifts operate at once during peak hours. A 2-tonne electric forklift can give off 3 kW to 5 kW of heat, putting direct pressure on the equipment unless spare capacity is allowed for at the outset.
Beyond the heat, materials handling equipment also determines the floor layout, the aisle widths between racking runs and the position of the structural columns in the store. A cold storage design that does not match the actual dimensions of the handling equipment cuts operating productivity by 20% to 30%, even with the compressor system working perfectly. To address this, Tân Long uses 3D simulation to optimise the clearances between modern storage systems such as robotic racking, double-deep racking or mobile racking and the store ceiling, ensuring cold air circulates throughout even at maximum stock density.
Ambient climate conditions
In Ho Chi Minh City and the southern provinces, the average outdoor temperature in the dry season reaches 34°C to 38°C at 70% to 85% relative humidity. These climate figures directly determine the insulated panel thickness and the condenser capacity. A store inside a factory building with a west-facing metal roof must add solar radiation of up to 600 W/m² (57 BTU/h·ft²) to the design heat load.
In northern Vietnam (Hà Nội, Hải Phòng), winter temperatures fall to 12°C to 15°C, significantly reducing the heat load on a chill room but increasing the risk of condensation on the outer face of the panels. The design engineer must allow for defrost heater elements in this climate.
Materials and construction in cold store design
PU (polyurethane foam) insulated panel is the standard envelope material for a modern industrial cold store. The panel consists of two galvanised or epoxy-coated steel facings around an injected PU foam core. The thermal conductivity (λ) of PU foam is 0.022 W/(m·K) to 0.024 W/(m·K), 30% lower than polystyrene (EPS) of the same thickness.
Standard panel thicknesses by temperature range:
| Store temperature | Wall/ceiling panel thickness | Floor panel thickness |
|---|---|---|
| 0°C to 10°C | 100 mm (4 inch) | 100–150 mm (4–6 inch) |
| -5°C to 0°C | 150 mm (6 inch) | 150 mm (6 inch) |
| -18°C to -25°C | 150–200 mm (6–8 inch) | 200 mm (8 inch) |
| Below −25°C | 200–250 mm (8–10 inch) | 200–250 mm (8–10 inch) |
Cam-lock panel fastenings ensure adjacent panels join tightly with no thermal gap. An assembly gap of more than 2 mm causes localised heat loss and creates a thermal bridge, increasing electricity consumption by 8% to 12%.
The door system is where heat ingress is most concentrated. Tân Long supplies cold storage sliding door and T-Light hinged cold store doors with multi-layer insulated aluminium frames, cold-resistant rubber gaskets and integrated anti-frost heater elements. A door built to standard has a heat loss coefficient no higher than 0.6 W/(m²·K).
The refrigeration system in an industrial store design
The refrigeration system is the technical heart of a cold store, comprising four components operating on the reverse Carnot cycle: the compressor, the condenser, the expansion valve and the evaporator.
Refrigeration compressor
The compressor is the largest consumer of electricity in a cold store, accounting for 60% to 75% of the system's total energy use. Tân Long uses screw compressors from Bitzer (Germany) and Carlyle (USA) for stores of 50 kW and above, and piston compressors for smaller stores under 30 kW. A screw compressor's COP of 2.8 to 3.5 saves electricity against a piston compressor of the same capacity.
The compressor pack needs a well-ventilated position, away from heat sources, with a minimum maintenance clearance of 1 m (3.3 ft) on all sides. The air temperature around the pack must not exceed 40°C if it is to deliver its design performance.
Evaporative condenser
An evaporative condenser rejects heat using water and air together, and is 20% to 30% more effective than a conventional air-cooled condenser in the hot, humid climate of southern Vietnam. For stores of 200 kW and above, the design favours an evaporative condenser to bring the condensing temperature down from 45°C to 35°C–38°C, reducing the load on the compressor by 15% to 25%.
Evaporators and air distribution
The industrial evaporators mounted at high level or on the ceiling distribute cold air evenly through the storage space. A fin spacing of 6 mm to 8 mm suits freezer stores, while chill rooms use 4 mm to 6 mm. The air velocity at the evaporator face is 2.5 m/s to 4.0 m/s (8.2 ft/s to 13.1 ft/s) to ensure even heat distribution.
Stores longer than 15 m (49 ft) need at least 2 evaporator units arranged symmetrically, to avoid a dead zone in the middle of the store.
PLC/SCADA control cabinet
PLC control cabinet integrates the whole operating logic of the store: starting and stopping the compressor automatically to the set temperature, scheduling automatic defrost cycles, and alarming faults by SMS or app. Tân Long also integrates SCADA allowing several stores to be monitored remotely on one central screen, with 24/7 temperature logging as HACCP requires.
Tân Long's cold store design process
Tân Long applies a standardised 4-step process to every cold store project, from survey to operational handover.
Step 1: site survey and capture of the technical requirements
Tân Long's engineers survey the site in person, measure the area, check the load-bearing capacity of the foundations (a cold store's distributed load is normally 1 to 3 tonnes/m²) and establish the orientation of the building to calculate solar gain. The team collects all 6 technical input parameters set out above before moving on to the calculation stage.
Step 2: heat load calculation and design drawings
The refrigeration load is calculated as: Q = Q_wall + Q_product + Q_infiltration + Q_equipment + Q_people. Dedicated heat load software (COOLPACK, Hysys Refrigeration) lets the engineer simulate operation before construction. The detailed CAD design drawings comprise the overall layout, the refrigerant pipework diagram (P&ID), the electrical control diagram and the equipment installation drawings.
Step 3: construction and installation
The insulated panels are installed in order: floor first, then walls, then ceiling. Every panel joint is checked for gaps and sealed with PU adhesive. The refrigerant pipework is installed, silver-brazed, charged and run up off-load. Building a 200 MT to 500 MT cold store normally takes 30 to 45 working days from start to finish.
Step 4: inspection, handover and operator training
Tân Long carries out a 72-hour continuous full-load test, recording temperatures at 8 to 12 measurement points distributed evenly through the store as HACCP requires. Handover includes the as-built technical documentation, written operating and maintenance procedures, and on-site training for the operators. Warranty is provided in line with the contract.
Common cold store design faults and how to correct them
After more than 20 years building cold stores, Tân Long's engineers see four design faults recurring on the refurbishment and repair projects they take on:
- Undersized refrigeration load: This happens when the engineer calculates only the static load and ignores heat ingress through the doors, the load from materials handling equipment and the heat in the incoming product. The result is a compressor running flat out continuously and still never reaching the design temperature, with its service life cut to 30% to 50% of normal. The remedy is to recalculate the heat load with a 15% to 25% safety factor and upgrade the compressor capacity.
- Insulated panels too thin, or assembly gaps: Many contractors use 100 mm panels for a −18°C freezer store to cut costs. The result is condensation on the outer wall face, heat loss up 40% to 60% and electricity costs soaring. A thermal camera survey identifies the thermal bridges immediately. The remedy is to add a 50 mm panel layer or replace the panels entirely.
- Evaporators poorly positioned: Evaporators placed too close to the door, or not arranged symmetrically, create temperature dead zones. Product in those zones is stored 3°C to 5°C above the design temperature. The remedy is CFD (computational fluid dynamics) analysis to simulate the airflow, plus additional circulation fans.
- No automatic defrost system: A freezer store with no scheduled defrost cycle builds up 2 cm to 5 cm of ice on the evaporator after 7 to 14 days in service, reducing its heat exchange capacity by 30% to 50%. A PLC controlling electric defrost or hot gas defrost on a 6 to 12-hour cycle solves the problem completely.
The cost of designing and building a cold store
The cost of designing an industrial cold store depends on three main factors: the operating temperature range, the floor area and the level of automation in the control system.
| Warehouse size | Acreage | Estimated cost (indicative) | Note |
|---|---|---|---|
| Small cold store (chill room) | 50–150 m² (538–1.615 ft²) | 400–900 million VND | Temperature 0°C–10°C |
| Medium cold store (freezer) | 200–500 m² (2.153–5.382 ft²) | 1.5–4 billion VND | Temperature −18°C to −25°C |
| Large cold storage | 500–2.000 m² (5.382–21.528 ft²) | 5–20 billion VND | NH3/CO₂ system |
| Logistics cold store | Over 2,000 m² (21,528 ft²) | Quoted per project | Bespoke design |
The cost covers: insulated panels, doors, refrigeration equipment (compressors, evaporators, condensers), refrigerant pipework, the control panel and installation labour. Equipment alone accounts for 55% to 65% of the total; the remainder is structure and labour.
A cold store built to standard saves 20% to 30% on electricity against a poorly designed one, through the right compressor capacity, the right panel thickness and inverter control. At an average electricity cost of 2,500 VND/kWh, a 200 MT store saves 50 to 100 million VND a year — paying back the additional investment in 3 to 5 years.
Why choose Tân Long to design your cold store?
Tân Long has designed and built cold stores in Vietnam since 2005. Over nearly 20 years, its engineers have completed more than 300 cold store projects from Ho Chi Minh City to Cà Mau, Sóc Trăng, Nghệ An and Hà Nội. They range from 50 MT chill rooms for restaurants and hotels to 12,000 MT freezer stores for seafood export processors such as Frescol Tuna, Ca Mau Seafood JSC and Vietnam Clean Seafood JSC.
Tân Long owns an equipment manufacturing plant in Đức Hòa 1 Industrial Park, Tây Ninh province, supplying PU insulated panels, evaporators, evaporative condensers and control panels made in-house. Controlling its own supply chain shortens construction time by 15% to 20% and allows quality control on every component before it leaves the factory.
Every cold store Tân Long hands over meets one of the following certifications: HACCP (food safety), ISO 22000 (food safety management systems) or GSP (good storage practice), according to the client's sector. These are mandatory requirements for businesses exporting to demanding markets.
Tân Long currently provides cold storage design consultancy entirely free of charge, to help businesses optimise their investment. You can contact our dedicated engineering team directly on (+84) 933 357 058 – Mr Thịnh, or by email at info@tanlongvn.com. Our office at 86 Đồng Đen, Tân Bình Ward, Ho Chi Minh City is always ready to arrange a site survey and provide detailed advice.
Frequently asked questions about cold store design
How long does a cold store design take?
The technical design stage (heat load calculation, CAD drawings, equipment selection) normally takes 7 to 14 working days for a store under 500 m². Larger stores over 1,000 m², or stores with several temperature zones, take 20 to 30 days.
What periodic maintenance does a cold store need?
An industrial cold store needs quarterly maintenance: checking refrigerant pressures, cleaning the condenser and evaporators, checking the door gaskets and calibrating the temperature sensors. Maintenance on schedule extends compressor life from 15 years to 20–25 years.
Which refrigerant is safest for a cold store?
In Vietnam, commercial cold stores use R404A and R134a (the most common), and are gradually moving to R448A and R449A under the HFC phase-out. Large industrial stores above 500 kW use NH3 (ammonia/R717), which has the highest COP but requires a separate plant room and specially trained operators.
Can a cold store be built on weak ground?
Yes, but the ground has to be treated first. The floor of a freezer store must have a ventilated floor system or underfloor heating elements to prevent frost heave causing settlement and cracking. Treating the ground adds 10% to 20% to the cost of an ordinary floor, but it cannot be skipped.
Frequently asked questions about cold store design
Where does cold store design start?
From establishing the type of goods, the temperature and humidity required, the daily volume in and out, and the storage duration. This is the input data for calculating the heat load and selecting the equipment.
Which factors determine the cold store design?
The total heat load, the operating temperature range, the dimensions and floor layout, the insulation thickness, the refrigeration approach and evaporator layout, the defrost system, and how goods are stacked so air circulates evenly.
Why should equipment not be chosen before the design exists?
Because equipment capacity has to follow from the calculated heat load. Choosing the equipment first and then building the store around it usually leaves capacity either short or excessive — and both push up running costs.
Should a cold store design allow for expansion?
Yes. Allowing in advance for expansion in floor space, compressor capacity and pipework lets a business scale up later without rebuilding the whole system.
Which design error has the longest-lasting consequences?
Under-calculating the heat load, floor insulation that is wrong for a deep-freeze store, and an evaporator layout that leaves air unable to reach the whole load — all three are very expensive to put right once the store is running.
Does Tân Long take on cold store design work?
Yes. Tân Long surveys the site, calculates the heat load, produces the design and delivers industrial cold stores on a turnkey basis.
