CO2 as a Refrigerant — Criteria for Choosing Refrigerants

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This is post two of CO₂ as a Refrigerant, a blog series covering the fundamental considerations and characteristics of CO₂ as a refrigerant (R-744).

When selecting any refrigerant, stakeholders must carefully consider multiple factors, including: cooling capacity, safety, environmental impacts, ease of use, costs, and availability of components and trained technicians. Table 1 summarizes these and other key criteria, while demonstrating how well R-744 meets them.

As Table 1 demonstrates, R-744 offers superior cooling capacity than legacy HFC refrigerants while meeting the demand for a sustainable alternative with low global warming potential (GWP). However, it also presents the challenges in both the application and handling of CO₂ as a refrigerant.

Table 1: Relative selection criteria and characteristics of R-744

In the next post of this CO₂ as a Refrigerant blog series, I’ll examine the properties of R-744 as a by-product of a naturally occurring substance (i.e., CO₂).