Stellar is gearing up for ATMOsphere America 2017, the leading forum for discussion about the business case for natural refrigerants in North America. The three-day conference next month will host more than 400 industry stakeholders in San Diego, California, and will feature discussions about the latest in refrigeration technology and regulation. Among the hot-button issues in the industry: the diminishing role of hydrochlorofluorocarbons (HCFCS).
With HCFCs being phased out worldwide by 2030 due to their harmful environmental impact, plant owners are searching for sustainable refrigerant alternatives. However, there is no one-size-fits-all solution.
Carbon dioxide (CO2) is commonly used as a cryogenic refrigerant, but it has also been used as the working fluid in mechanical refrigeration systems as far back as the 1800s. Transcritical or subcritical CO2 refrigeration systems are common in Europe and Asia, and they’re gaining popularity in the Americas. In the northern U.S. and Canada, transcritical CO2 systems have become a cost-effective choice in many food processing, cold storage and commercial facilities. Subcritical CO2 cascade and volatile brine systems are best used for low-temperature freezing and higher temperature secondary refrigerant applications.
Mechanical refrigeration using CO2 can be an attractive alternative to other refrigerants, but many have written off the refrigerant due to these common misperceptions:
Myth #1: CO2 is too dangerous
Given the right conditions, all refrigerants have the potential to cause harm. Some of the characteristics that drive fear of CO2 are the same that provide its benefits. High operating pressure is “scary,” but it’s the feature that enables lower equipment costs and greater energy efficiency. With proper design, construction and commissioning, a mechanical CO2 system is just as safe as any other.
Myth #2: CO2 refrigeration requires leak detection that other refrigerants don’t
Like many refrigerants, CO2 is a colorless and odorless vapor. Thus, it does require leak detection in the machine room as well as the cold rooms. However, leak detection instrumentation is required in unmanned machine rooms regardless of the refrigerant. In fact, many operators require leak detection for ammonia in the cold rooms too, despite its self-alarming odor. Cryogenic CO2 is widely used in processing facilities with ventilation and leak detection at the points of use. It is important to note that the right leak-detection technology is required with CO2 because of its presence in the human body. Instruments that only measure oxygen levels are not adequate.
Myth #3: A CO2 system is more expensive to install and operate
In most cases, CO2 cascade systems are less expensive to install and operate than two-stage ammonia systems for low-temperature applications.
The unique physical properties of CO2 provide an advantage when used as a secondary refrigerant for higher-temperature applications, too. Its high vapor density and volatility combine to achieve much smaller piping and pumping requirements when compared to chilled glycol systems, thus reducing capital and operating costs. As a volatile brine, CO2 can provide energy savings of up to 10-20 percent for high temperature systems and 20 to 30 percent for medium temperature systems.
When investing in a new refrigeration system, owners and operators should consider using CO2 cascade or volatile brine systems. Whether looking to minimize ammonia charge, reduce carbon footprint, or both, CO2 is often a viable and cost-effective option, providing:
- Cost-effective installation and operation
- Improved energy efficiency when compared to glycol
- Reduction in ammonia charge and PSM compliance costs
- Sustainability with 0 ozone depletion potential (ODP) and 1 global warming potential (GWP)
Are you attending ATMOsphere 2017? Be sure to connect with the Stellar group who will be there. Want to learn more about the viability of implementing a CO2 system in your food processing or distribution facility? Feel free to email me at firstname.lastname@example.org