Other fields of application where refrigeration systems are required include aerospace, superconductivity, and cryogenics. Below, Inditer provides a schematic explanation of the industrial refrigeration cycle.

Industrial Refrigeration | Inditer

Industrial refrigeration is one of the great cornerstones of our society. Through the production of cold—that is, the process of lowering or maintaining the temperature of a product or space—it is possible to transport and preserve perishable goods, as well as facilitate a vast number of industrial processes fundamental to our daily lives.

At Inditer, we work every day on the main components within the refrigeration cycle by manufacturing a wide range of products to always meet customer needs. These products include Evaporators, Condensers, and Gas Coolers, placing us at the forefront of technology to improve performance and, consequently, the efficiency of industrial refrigeration installations.

Where can we find these industrial refrigeration systems?

Industrial Refrigeration is present in various fields of application:

• Food industry: Food preservation tasks, product ripening (fruit), processing of pre-cooked foods, meat industries, dairy… It should be noted that it is currently estimated that 70% of food is chilled or frozen, which demonstrates the magnitude of the importance of industrial cooling in our daily lives.
• Food transport and distribution: It is essential not to break the cold chain to preserve the characteristics of refrigerated products.
• Medicine and health: It is of vital importance in many healthcare processes. For example, preserving vaccines between 2°C and 8°C is necessary for their correct use.
• Chemical Industry: In this sector, pressurized gases at specific temperatures are often required for the manufacture of organics, inorganics, pigments, plastics, fibers, and chemicals. In the petroleum industry, cooling is also used in vapor pressure control systems or to change solubility ratios.
• Power generation: Occasionally, electricity generation is carried out through internal combustion equipment for which specific cooling systems are necessary.
• Other fields of application where refrigeration systems are required include aerospace, superconductivity, and cryogenics.

Below, Inditer provides a schematic explanation of the industrial refrigeration cycle.

 

What is the industrial refrigeration cycle?

The refrigeration cycle consists of a set of elements that absorb heat from the medium to be cooled and subsequently transfer this heat to the environment through the circulation of a refrigerant fluid, generated by work. This refrigerant fluid has specific characteristics depending on the one selected, which provides more or less advantageous qualities when transmitting energy under certain pressure and temperature conditions. It is important to be aware of its limitations and its influence on the surrounding environment, always complying with Royal Decree 552/2019, the “Safety regulations for refrigeration installations and their complementary technical instructions.”

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The components of the basic refrigeration cycle, explained in the following section, refer to compression equipment (> 99% at present, due to performance and application range); the remaining 1% consists of absorption equipment, generally water-lithium bromide, or air.

Components of the industrial refrigeration cycle

The basic elements of the refrigeration cycle are as follows:

• The compressor

Its function is to compress the gases coming from the evaporator, thereby increasing their pressure and, consequently, their temperature. At the compressor outlet, the gas is at high pressure and at a temperature above the heat sink, making it ready to enter the condenser. The work performed by the compressor affects energy consumption, making its sizing and control a fundamental parameter for the total performance of the installation.

There are different types of compressors, the most common in refrigeration being positive displacement compressors, particularly reciprocating compressors for low-to-medium power and screw compressors for medium-to-high power.

• The condenser

This is the element responsible for dissipating the heat power absorbed in the evaporator and the compression power of the compressor. There are different types of condensers, notably:

• • Cooling towers (open and closed systems)
  • Evaporative condenser
  • Dry air-cooled condenser
  • Gas Cooler, in the case of CO2 as a refrigerant, in transcritical conditions

• The expansion valve

Its function is to generate a pressure drop between the condenser and the evaporator. Only liquid should reach the expansion valve, so it is common to find a liquid receiver at the condenser outlet to ensure there is no gas present at the valve inlet.

Currently, the most common expansion valves in commercial and industrial refrigeration are thermostatic and electronic; with them, we are able to control the flow of refrigerant reaching the evaporator and, therefore, control the conditions of our system. In the case of dry expansion, this control relies on temperature and pressure probes that regulate the superheat at the evaporator outlet, thus avoiding the dangerous entry of liquid into the compressor suction.

• The evaporator

This is the element responsible for absorbing thermal energy from the medium to be cooled, taking advantage of the change of state (from liquid to gas), known as latent heat. They are usually tube and fin heat exchangers with forced ventilation. There are numerous structures depending on their application, the most common being:

• Cubic evaporator
• Double flow or ceiling-mounted evaporator
• Low profile evaporator
• Wall-mounted evaporator

• Auxiliary elements

It should be emphasized that beyond these basic elements that appear in any compression refrigeration system, we can find numerous auxiliary elements, including:

Shut-off, cut-off, and non-return valves, filter driers, sight glasses, liquid receivers, oil separators, siphons, ejectors, etc.

Operation of the industrial refrigeration cycle

In a very summarized way, the operation of the industrial refrigeration cycle is as follows:

The refrigerant fluid is drawn in by the compressor up to the condensing pressure; in this process, its pressure increases and, with it, its temperature rises above ambient conditions. For this process to be feasible, electrical consumption is required to allow for this mechanical compression.

Once the refrigerant is at high pressure, it passes to the condenser. A temperature difference is necessary between the heat sink and the evaporation temperature. Depending on this difference, as well as the materials of the heat exchanger, the equipment will be of one size or another. In the condenser, the fluid changes from a gaseous state to a liquid state, dissipating this heat to the outside.

This high-pressure liquid leaving the condenser enters the expansion valve, which is responsible for controlling the flow in the system and reducing the refrigerant pressure through throttling down to the evaporation pressure, also called low pressure.

In the evaporator, heat is absorbed from the medium to be cooled by taking advantage of the latent heat present in the phase change, in this case from liquid to gas. Just as in the condenser, a thermal jump between the cold source and the evaporation temperature is necessary for heat transfer to occur.

Once the refrigerant leaves the evaporator in a gaseous state, it re-enters the compressor, starting the cycle again.

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