A fundamental understanding of what exactly it functions on industrial refrigeration equipmentis critically important for engineers and technologists and owners of warehouse complexes. Unlike household analogues, industrial installations are complex engineering systems, where the operating principle is based on a continuous cycle of compression and expansion of the working fluid. The main source of energy to start this process is electric current, which drives the compressor group, which is the heart of the entire system.
However, when talking about “what” the refrigerator operates on, we cannot limit ourselves to electricity alone. The key element that transfers thermal energy is coolant a special substance that changes its state of aggregation at different pressures. It is the circulation of this gas or liquid that allows heat to be removed from the cooled object and dissipated into the environment. Without a properly selected refrigerant, even the most powerful electric motor will be useless.
It is important to consider that modern requirements for ecology and energy efficiency dictate new standards for refrigeration units. Where once the priority was solely on cooling power, today engineers pay close attention to the type of refrigerant used and the energy class of the engine. Understanding these nuances allows you not only to reduce operating costs, but also to avoid fines for violating environmental standards.
Electric energy as the main power source
The vast majority of industrial refrigeration machines operate from the electrical network. Electricity consumption is the main cost item in the operation of such installations. Compressor motors, condenser and evaporator fans, as well as control and automation systems require stable voltage and a certain current frequency. Large logistics centers often use three-phase networks 380V, which allows you to run powerful units without overloading the wiring.
The energy efficiency of modern equipment directly depends on the type of electric motor used. Traditional asynchronous motors are gradually giving way to more advanced solutions. Inverter control allows you to smoothly regulate the rotation speed of the compressor shaft, adjusting the performance to the current thermal load. This eliminates frequent starting currents, which are the most energy-intensive and wear out the equipment.
⚠️ Attention: Industrial refrigerators are sensitive to voltage drops in the network. Sudden surges can damage electronics or burn out motor windings. It is recommended to use voltage stabilizers or uninterruptible power supplies for critical storage systems.
In some specific environments where access to electricity is limited or unstable, absorption chillers may be used. They operate by burning gas (natural or propane-butane) or even waste heat from industrial processes. Although such systems are less common, they demonstrate that energy source can vary depending on the available resources of the enterprise.
Refrigerants: working fluid of the refrigeration cycle
If electricity is the “muscle” of the system, then the refrigerant is her "blood". It is this substance, circulating in a closed circuit, that transfers heat. On an industrial scale, the requirements for the working fluid are much higher than in everyday life. It must have high heat capacitychemical stability, safety for personnel and minimal impact on the environment. The choice of a specific type of refrigerant determines the design of all equipment.
Historically, the industry has gone through several generations of refrigerants. From toxic and flammable substances (ammonia, sulfur dioxide) we moved on to freons (CFC, HCFC), which turned out to be destructive to the ozone layer. The modern stage is marked by a transition to hydrofluoroolefins (HFO) and a return to natural refrigerants such as carbon dioxide (CO2) and propane, but in improved high-pressure systems.
The table below shows comparing the main types of refrigerants used in industry:
| Refrigerant type | Examples of brands | Global Warming Potential (GWP) | Scope of application |
|---|---|---|---|
| Ammonia (R717) | Pure ammonia | 0 | Large food factories, ice arenas |
| Carbon dioxide (R744) | CO2 | 1 | Supermarkets, cascade systems |
| Fluorine-containing (HFC) | R404A, R507 | High (>3000) | Warehouse complexes (gradually being withdrawn) |
| Hydrofluoroolefins (HFO) | R1234yf, R513A | Low (<1) | New environmentally friendly installations |
The choice working substance is also dictated by the temperature regime. For deep freezing of products (below -40°C), cascade systems are often used, where one refrigerant operates in the first circuit, and another with a lower boiling point operates in the second. This allows you to achieve extremely low temperatures with high efficiency.
Why is ammonia still used?
Ammonia (R717) has excellent thermophysical properties and zero impact on the climate. Despite its toxicity and flammability, with proper design and compliance with safety standards, it remains the most effective and cheapest refrigerant for large industrial facilities.
Types of compressors: the heart of the refrigeration machine
The compressor is the main mechanical unit that circulates the refrigerant. It creates the necessary pressure, causing the gas to condense and evaporate at the desired points in the cycle. There are several types of compressors used in industry, each with its own advantages and applications. The reliability and working life of the entire installation depend on the correct choice of this unit.
Piston compressors are considered classics of the genre. They are reliable, maintainable and capable of operating in a wide temperature range. However, they have a level of vibration and noise. Scroll (scroll) compressors operate quieter and smoother, with high efficiency, but their repair often requires replacing the entire unit rather than individual parts.
- 🌀 Screw compressors: Ideal for medium and large capacities, providing continuous operation 24/7 with minimal maintenance.
- ⚙️ Piston units: Time-tested technology, excellent for systems with variable loads and difficult starting conditions.
- 🚀 Turbocompressors: Used in heavy-duty chillers for cooling large volumes of liquid, operating at high rotation speeds.
Modern screw compressors are often equipped with a capacity control system. This allows you to change the volume of gas pumped without stopping the engine. Such flexibility is critical for maintaining a stable temperature in the chamber during a changing heat load, for example, when loading a new batch of products. For objects with a continuous cycle of operation (warehouses, factories), screw compressors are the most preferred choice due to their durability and the ability to operate without stops. chamber temperature when the heat load changes, for example, when loading a new batch of products.
Condensation and heat removal systems
The operation of a refrigerator is impossible without effective removal of heat received from cooled objects. This process occurs in the condenser, where the hot gas compressed by the compressor turns into liquid. On an industrial scale, air or water condensation systems are used for this. The choice between them depends on the availability of water resources, climatic conditions and energy consumption requirements.
Air condensers are radiators with powerful fans. They are easier to install and operate, and do not require water treatment or pumping stations. However, their effectiveness decreases in hot weather when the ambient temperature is high. In addition, they occupy a significant area and can create noise pollution.
Water systems (cooling towers) remove heat much more efficiently due to the high heat capacity of water. They allow you to stabilize the condensation pressure all year round, which improves the overall energy efficiency system. However, such a scheme requires complex infrastructure: pumps, pipelines, water treatment systems to prevent scale and biological fouling.
⚠️ Attention: When operating water cooling towers in winter, it is necessary to provide protection against freezing. Residual water in pipelines can expand during crystallization and rupture metal structural elements, which will lead to expensive repairs.
Automation and control systems
A modern industrial refrigerator is not just a set of pipes and motors, but a high-tech complex controlled by electronics. The “brain” of the system is the controller, which processes data from dozens of temperature, pressure and humidity sensors. Based on this data, the automation makes decisions about turning on compressors, opening valves and starting defrosting.
Use programmable logic controllers (PLCs) allows you to integrate the refrigeration unit into a unified enterprise management system (SCADA). The operator can see equipment status, power consumption and temperature graphs in real time from any device connected to the network. This greatly simplifies monitoring and fault diagnosis.
Protection functions in modern control systems come to the fore. Automation monitors:
- 🛡️ Pressure: Emergency shutdown when the pressure in the circuit is too high or low.
- 🌡️ Temperature: Control of oil overheating in the compressor and discharge temperature.
- ⏱️ Time: Timers to regulate operating cycles and prevent frequent starts (anti-cyclic protection).
Intelligent systems are able to predict the need for maintenance. By analyzing current consumption and vibration, the controller can report wear on bearings or contamination of heat exchangers before a breakdown occurs. This approach, known as predictive analyticsis becoming an industry standard.
Energy efficiency and environmental standards
The question of what refrigerators run on goes hand in hand with the question of how many resources they consume. Industrial refrigeration equipment belongs to the class of energy-intensive equipment. The introduction of new energy efficiency standards forces manufacturers to reconsider the designs of heat exchangers, use premium motors (IE3, IE4) and optimize operating algorithms.
The environmental aspect also dictates its own rules. International agreements (Kyoto Protocol, Kigali Amendment) require the phasing out of refrigerants with high global warming potential. This stimulates the transition to natural refrigerants and new generation synthetic mixtures. Equipment running on “old” freons becomes less attractive due to the high cost of maintenance and the risk of future bans.
An important indicator is the coefficient of performance (COP) of the refrigeration machine. It shows the ratio of the cold received to the energy expended. Increasing COP even by a few percent provides enormous cost savings over the course of a year of operation of a large logistics center. Therefore, investments in more efficient, but expensive equipment often pay off due to reduced electricity bills.
☑️ Checking the energy efficiency of the system
How often do you need to change the refrigerant in an industrial refrigerator?
Refrigerant in a closed circuit has no lifespan shelf life and can theoretically circulate for decades. Replacement is required only in case of leakage, contamination of the system (for example, when motor windings burn out) or when upgrading equipment to a new type of working substance. Regular refueling due to “natural consumption” indicates a malfunction of the circuit.
Is it possible to convert an old refrigerator to a new environmentally friendly gas?
Direct replacement (“drop-in”) is not always possible. Switching to a new refrigerant often requires changing the compressor oil (if the chemical group is changed), seals, and sometimes heat exchangers. It is necessary to carry out careful engineering calculations and coordination with the equipment manufacturer, since different gases have different operating pressures and temperatures.
What happens to the refrigerator when the power is turned off?
When the power is lost, compressors and fans stop. The temperature in the chamber begins to rise. The speed of defrosting depends on the quality of thermal insulation, the density of product loading and the tightness of the doors. Modern controllers have a “memory” function that allows you to resume operation with the specified parameters immediately after voltage appears, but for critical loads, backup generators are needed.