Refrigeration Units

A modern cold store is no longer just a "cold room". It is a complex, high-tech engineering facility in which precise control of temperature, humidity and airflow is the main guarantee of product safety.

A successful refrigeration facility starts with correct engineering calculations. Investors and project designers must take several critical factors into account:

• Strict industry standards: when designing specialized facilities (for example, pharmaceutical warehouses), compliance with GDP (Good Distribution Practice) standards is mandatory. This requires continuous, documented monitoring of the temperature regime and absolute system reliability.
• Accurate calculation of capacity and system architecture: selecting a compressor alone is not enough. In large warehouses, what works is the proper integration of high-capacity chillers, large buffer tanks and a correctly designed network of ventilation ducts (duct layouts), so as to eliminate "dead zones" and temperature fluctuations.
• Airflow stability: for best results, commercial-grade CAV (Constant Air Volume) regulators are often integrated into the ventilation system, ensuring a constant and even supply of air to the chambers.
• Thermal insulation: high-density PIR or PUR sandwich panels are used for the chamber walls, reducing heat losses to a minimum.

Like any technological solution, modern refrigeration systems have their own specific features:

Successful businesses in the market choose only time-tested brands. The system consists of two main parts:

• Outdoor units (compressors and condensers): products from giants such as Bitzer (Germany), Copeland (USA) and Danfoss (Denmark) are regarded as the industry standard. Their units withstand extreme loads and operate without interruption.
• Indoor units (evaporators) and insulation: Güntner and Alfa Laval lead in efficient air cooling, while in thermal insulation the sandwich panels of Kingspan and Ruukki are recognized worldwide.

Best practice: modern pharmaceutical hubs and large distribution centres use redundant systems. For example, when the main chiller undergoes scheduled inspection, the system automatically starts the standby unit, while large buffer tanks maintain the cold reserve in the system during the transition, which completely eliminates the risk of product spoilage.

Integrating refrigeration units with a BMS (building management system) is the step that turns isolated refrigeration equipment into part of a single, "intelligent" building organism. This is especially critical for large industrial facilities, where chillers, CAV and VAV regulators, ventilation and heating systems all operate at the same time.

How Integration Works: The Technical Side

Integration is carried out using a common communication language — protocols. The most widely used standards are:

• Modbus (RTU / TCP-IP): the industrial standard. A robust, simple and reliable protocol used by most refrigeration units for data transmission.
• BACnet: a protocol designed specifically for building automation. It makes it easy to link cold rooms with ventilation and fire safety systems.

Physical connection: the controller of the refrigeration unit (for example, a Bitzer or Danfoss compressor) is connected by a dedicated cable to the BMS central processor or network switch. The BMS reads the controller's data (temperature, pressure, motor speed) and sends control commands back.

Key Benefits of BMS Integration

An integrated BMS is the essential component that distinguishes a modern, reliable cold store from a mere cold space.

In small industrial refrigeration chambers, installing a full BMS is often not financially justified, yet precise temperature control and data recording remain critically important. In such cases, alternative methods of local automation and monitoring are used.

1. Local Microprocessor Controllers

This is the "brain" of the cold room. Industrial controllers from brands such as Dixell, Eliwell or Danfoss (for example, the ERC or Optyma series) control the unit directly.

• Function: they independently regulate compressor on/off switching, fan operation and defrost cycles based on information from temperature sensors.
• Advantage: they have a digital display for easy parameter setting and a built-in audible alarm (buzzer) that sounds when the room temperature deviates beyond the permitted range.

2. Standalone Data Loggers

When storing pharmaceuticals or other sensitive products, compliance with GDP (Good Distribution Practice) standards is mandatory, which requires continuous, documented and tamper-proof temperature monitoring.

• How it works: the logger is installed inside the chamber and records temperature and humidity to its internal memory at a set interval (e.g. every 15 minutes).
• Reliability: data is retrieved via USB, Bluetooth or Wi-Fi. The logger is independent of the refrigerator's power supply (it runs on its own battery), which rules out data loss during power failures. The system automatically generates tamper-proof PDF reports for audits.

3. IoT and Cloud Telemetry

This is an intermediate step between a local controller and a complex BMS, ideal for small and medium-sized businesses.

• Technology: a small GSM or Wi-Fi module (gateway) is installed in the chamber control panel and connected to the local controller.
• Result: data is sent in real time to the manufacturer's cloud server. In the event of a temperature deviation or a power outage, the responsible engineer or owner instantly receives an SMS, email or push notification on their smartphone, which is the best way to prevent critical failures and product spoilage.

Depending on the specifics of your facility, you can use the interactive tool below to choose the optimal monitoring system:

Selecting Cold Room Equipment

A precise engineering calculation of the cooling capacity (kW) required for a small refrigeration chamber involves finding the sum of all heat loads present in the chamber. The aim is to determine how much heat the unit must remove from the chamber over a given period (usually 24 hours) to maintain the desired temperature.

The calculation is based on the sum of four main components.

The 4 Critical Components of Heat Load

The total required capacity is expressed by the following formula:

This calculator will give you a basic idea; however, for a real project it is standard practice to use engineering software (for example, Bitzer Software or Danfoss Coolselector).

In industrial refrigeration, choosing a refrigerant is not just a matter of reaching the target temperature — it dictates the entire engineering architecture of the system, the piping material, safety regulations and energy efficiency.

Synthetic refrigerants, ammonia (NH3) and CO2 have radically different thermodynamic and chemical properties.

1. Ammonia (NH3 / R717): The Industrial Giant

For more than 100 years ammonia has remained the gold standard of industrial refrigeration, although its specific properties demand a rigorous engineering approach.

• Thermodynamics: it has the highest heat absorption coefficient (latent heat). An ammonia system consumes much less electricity to deliver the same capacity than one using a synthetic refrigerant (so-called freon).
• Material restrictions: ammonia is corrosive to copper and brass. Accordingly, ammonia systems use only steel or stainless steel pipes and specific, heavy-duty compressors.
• Oil management: ammonia does not mix with compressor oil, so the system requires complex oil separators.
• Safety: it is highly toxic. It requires complex safety systems: leak sensors, automatic ventilation shafts and, in some cases, water scrubbers (water absorbs ammonia in the event of an accident).

2. CO2 (Carbon Dioxide / R744): Ultra-High Pressures

In recent years, driven by environmental regulations, CO2 has undergone a huge renaissance, especially in supermarkets and large warehouses.

• Thermodynamics: it has a very high volumetric capacity. This means that compressors and pipes can be much smaller than with synthetic refrigerants or ammonia.
• Engineering challenge (pressure): CO2 systems operate at extremely high pressures. While the working pressure in a synthetic refrigerant system is 15–20 bar, in a transcritical CO2 system (in summer) the pressure can reach 90–120 bar. That is why its piping is made from special K65 alloy copper or thick-walled steel.
• Transcritical cycle: above 31°C, CO2 loses its ability to condense (it does not liquefy). In hot climates the system switches to transcritical mode, which complicates the refrigeration cycle and requires gas coolers instead of condensers.

3. Synthetic Refrigerants (So-Called Freon) (HFC/HCFC, e.g. R404A, R134a, R507): The Commercial Standard

Synthetic refrigerants are the most widespread because of their simplicity and safety.

• Engineering simplicity: they operate at low and medium pressures. They are compatible with standard copper pipes, which makes installation considerably cheaper.
• Oil management: freon mixes well with synthetic (POE) oils, which ensures easy oil return to the compressor.
• Environmental dead end: their main problem is a high global warming potential (GWP). Under European regulations (the F-Gas directive), their use is being gradually banned, which makes them unviable for new industrial projects.

Summary Engineering Comparison

Using the interactive panel below, you can visually compare these three systems across various parameters: