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There is no denying that the economic landscape has shifted in the past couple of years. An increased need for cold storage facilities, pharmaceutical manufacturing, food processing, warehousing and distribution has elevated the global demand for industrial refrigeration solutions.

Companies are looking for industrial refrigeration systems that support the integrity of the cold supply chain and meet the critical requirements necessary in many industries when it comes to their cooling operational processes. That need will continue to grow, and with that growth comes the rise in demand for innovative technologies and operational efficiencies as well as a desire to move toward natural, eco-friendly refrigeration solutions.

A renewed look at these alternative natural refrigerants is being driven by the imminent phasing out of synthetic refrigerants due to their adverse environmental impact. Natural refrigerants are viable alternatives when it comes to industrial application cooling needs. They are energy efficient due to their thermodynamic properties and, in many applications, offer a lower total cost than synthetic alternatives such as HFCs. More than that, natural refrigerants are understood to be safer for the environment because they have been shown to have little or no global-warming potential (GWP) and ozone-depletion potential (ODP). These characteristics make them a good long-term investment for fighting climate change.

Frequently used in the industry, ammonia (NH3) is one of those refrigerants. It has zero GWP or ODP, making it an attractive refrigerant for businesses seeking long-term sustainable operations. Ammonia has been used widely in industry because of its low cost and thermodynamic efficiencies. Ammonia also is accompanied by some risks, and these risks have businesses looking at safer alternatives. As a result, carbon dioxide (CO2) has been making headway as a process cooling and industrial refrigeration solution.

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The use of a CO2 system in industrial applications makes it possible and practical for businesses of all sizes to build cold storage infrastructures, food processing environments and warehousing and distribution facilities. Image provided by Hillphoenix

CO2 is certainly not new to the world of refrigeration: This naturally abundant Class A1 refrigerant has been used in refrigeration systems since the 1800s. It offers many advantages for industrial operations. With the introduction and wide use of synthetic refrigerants such as CFCs and HCFCs in 1929, however, the use of CO2 refrigeration decreased. Barriers and concerns about using CO2 as a refrigerant have been the main drawbacks to its full reintegration into the refrigeration industry. But technological innovation like CO2 transcritical booster systems is once again bringing CO2 to the forefront of industrial refrigeration solution discussions.

Refrigerants like ammonia are highly regulated by a variety of state and federal agencies. Noncompliance with applicable regulations, including those related to proper storage and handling, can result in a variety of adverse consequences, including civil penalties and fines.

Debunking Myths About CO2 for Industrial Refrigeration

One common myth regarding CO2 is that it is not safe. Contrary to this belief, this natural substance is both safe for the environment and can be safely used in industrial applications by trained personnel.

CO2 is known to be environmentally benign with a zero ODP and GWP of 1. And as a nontoxic, noncorrosive and nonflammable refrigerant, CO2 significantly reduces or eliminates many of the inherently adverse issues found with other refrigerants like ammonia, HCFCs, HFCs and HFOs. This positions carbon dioxide as compliant with both current and planned future regulatory requirements; thus, it allows businesses to avoid costly operational disruptions and potential financial penalties.

CO2 is safe as long as it is used under the right conditions. (It is important to properly train personnel and employ appropriate design and handling techniques.) The materials and components of CO2 systems are designed and manufactured to operate safely and efficiently at elevated pressures. In fact, the characteristics of its inherent operating pressure offer the additional benefit of utilizing the higher pressure to provide a higher volume of heat for heat reclaim and subsequent usage elsewhere in the facility. This feature results in overall energy cost savings for the processing facilities.

Because carbon dioxide systems provide sufficient heat for use in many heat recovery applications, they naturally lend themselves to heat pump duty, providing simultaneous cooling and heating. The reclaimed heat returned to a facility can be used to create hot water; thus, such an approach can offset a significant amount of fossil fuels that would otherwise be consumed in boilers. This results in an overall plant efficiency far better than traditional designs.

In general, the overall annual energy efficiency or refrigeration operating costs of CO2 systems outweigh the cost of synthetic refrigerants (approximately 5 to 25 percent), but they are not quite as energy-efficient as ammonia (-2 to -10 percent). But, when the heat reclaim capabilities of CO2 are factored into the overall efficiency calculations, CO2 will fare better than (or exceed the efficiency of) the other refrigerants. Many variables affect the difference:

  • The low-side operating temperature (coolers, freezers, etc.).
  • Ambient temperature. CO2 is more efficient in northern climates than in southern climates.
  • Refrigerant type (in the case of synthetics).

Another misconception is that CO2 is expensive. In fact, CO2 is readily available and inexpensive to produce and charge refrigeration systems when compared to many of the alternatives. Reduced pipe and component sizing, combined with the low cost of the refrigerant, contribute to cost savings on installation and an overall smaller equipment footprint.

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Carbon dioxide is both safe for the environment and can be safely used in industrial applications by trained personnel. Image provided by Hillphoenix

Carbon dioxideʼs high volumetric cooling capacity can reduce costs because it allows the use of smaller pipes and compressors. Likewise, its high heat transfer characteristic leads to a reduction in the size of evaporators and condensers. Carbon dioxide equipment — like transcritical CO2 booster systems — has become far more commonplace in the industrial refrigeration industry.

The viability of CO2 and the multitude of benefits it offers make it one of the best natural alternatives available for use today. Carbon dioxide is being increasingly used, and the innovation occurring in the industry with equipment and natural refrigerants continues apace. The use of a CO2 system in industrial applications makes it possible and practical for businesses of all sizes to build cold storage infrastructures, food processing environments and warehousing and distribution facilities. With a team of experts trained to handle CO2 for industrial refrigeration, businesses can adopt CO2 systems safely and efficiently and the industry could realize huge gains moving forward.