Cold Systems LLC Vertical ammonia reciprocating compressor driven by a steam engine circa 1890. Atmospheric Condenser Ice sheet production facility circa 1900.

Industrial Refrigeration Systems using Ammonia, CO2, or Hydrocarbons

Industrial Refrigeration Systems

Industrial refrigeration systems are noted for their complexity and uniqueness between similar facilities. These systems operate under widely varying operating conditions to meet specific cooling processes at various temperatures. This range of conditions and requirements dictate the need for custom engineering of every system. In fact, it is uncommon to find two identical systems.

These systems utilize various sub-systems consisting of many different components and refrigerants that are utilized for specific purposes. Coupled with the fact that no two systems are alike, each system can exhibit different performance and efficiency characteristics.

Typical sub-systems and components found in industrial refrigeration systems are:

In some cases, the application of these components or sub-systems is determined by the system designer’s preference or past experience. Systems are often found to be designed for one point of operation, i.e., full capacity in the summer. Other periods of operational requirements may directly impact the overall efficiency of the refrigeration system.

Each component has a specific performance capability at one point of operation. Any combination of these components and sub-systems at other points of operation can be detrimental to energy conservation efforts. In effect, the overall system design can include unknown barriers which limit the potential for energy reduction.

One of the major challenges for operators and owners of industrial refrigeration system is the ability of the refrigeration system to work efficiently in any operating condition. The operating costs of your refrigeration system are determined by this.

However, these barriers can be determined by analysis. A through investigation of the various components, sub-systems and operational characteristics of your system can provide cost-effective solutions to help reduce your energy dependency.

Industrial Refrigerants

Anhydrous ammonia is the most common refrigerant used in industrial refrigeration today and is often referred to as; R-717, ammonia, or NH3. The application of ammonia to refrigeration systems has become universally known as the field of industrial refrigeration.

Ammonia has the distinct advantage of a high latent heat and excellent heat transfer properties. Ammonia is also readily available at an economical cost when compared to other commercial refrigerants. These combined advantages are the principle reasons why ammonia is utilized in large refrigeration systems.

From an environmental viewpoint, ammonia has no ozone depletion or global warming potential and is biodegradable.

Carbon dioxide (CO2 or R-744) has been extensively used in the past. It is undergoing a popular resurgence and has distinct advantages for low temperature applications. One of the benefits of using CO2 in low temperature refrigeration system is the low specific volume of the refrigerant vapor. This has a direct positive impact on the required compressor displacement (ft3/min or m3/min) and can help to reduce the installed size of the compressor(s).

CO2 is also considered a high-pressure refrigerant. A CO2 refrigeration system that experiences an emergency shutdown or power outage may require additional measures to contain the refrigerant.

The use of CO2 as a refrigerant does not contribute to the greenhouse gas problem as this is simply recovered gas from the atmosphere.

Propane (R-290) or Propylene (R-1270) are two other examples of common refrigerants known as hydrocarbons. These are commonly found in large chemical processing or refinery facilities. While propane and propylene are suitable as refrigerants they are also flammable gases. This restricts their use to facilities where the requirements of specific area classifications such as explosion proof electrical devices are common place.

The refrigerant selected for an industrial refrigeration system should be based on the actual requirements of the cooling process. Some refrigerants offer significant benefits over other refrigerants for specific reasons. Additional criteria may include; safety considerations, operating temperatures, familiarity with the refrigerant and its specific requirements, or ease of integration into existing infrastructure.

Refrigeration Piping

Refrigeration piping is another critical aspect of industrial refrigeration systems. Simply selecting the appropriate components and applying them to the total refrigeration system is only a small piece of the puzzle. The performance of each component is based on a specific operating condition consisting of pressure, temperature, and duty requirements.

Since all of these components and sub-systems are connected by the piping, it is important to eliminate any adverse impact by applying proper selection and installation techniques.

Piping, valves, or fittings need to be carefully evaluated to prevent excess pressure loss. With any pressure loss there is a corresponding temperature loss and the distinct possibility of creating performance or operational problems. In a similar viewpoint this can also lead to an increase in energy use or a loss of cooling capacity.

The challenge is to carefully select and install the correct pipe sizes so the component performance is not negatively affected. This is of critical importance in specific areas such as; gravity drainage of evaporative condensers, thermosiphon oil cooling systems, high-pressure liquid lines, and low-temperature suction lines.

In essence, the piping system is a critical element that determines the performance of each component and sub-system and the overall capacity of your industrial refrigeration system.

We can help you to understand the impact of system configurations, components used and piping related issues to assist you in lowering your total operating costs of your industrial refrigeration system.

Be sure to see the CO2 Refrigeration page for information about the use of carbon dioxide as a refrigerant. See the Refrigerant Reference Bulletins for detailed information about the properties of various refrigerants.