What is one refrigerant used in low pressure refrigerated appliances?

R-123 is a refrigerant commonly used in low-pressure refrigeration systems, particularly in chillers and some air conditioning applications. Its low-pressure characteristics make it suitable for these types of systems, where efficient heat transfer is critical. R-123 has a relatively low boiling point and provides good thermodynamic properties at low-pressure ranges, allowing it to function effectively in applications designed for low-pressure refrigerants.

Other refrigerants listed, such as R-134a, R-410A, and R-22, operate at higher pressures. R-134a is typically used in medium-pressure applications, while R-410A is designed for high-pressure systems, primarily in residential and commercial air conditioning. R-22 is a refrigerant that has historically been used in both low and medium-pressure applications, but it is being phased out due to environmental concerns.

The specific designation of R-123 for low-pressure applications is a significant characteristic that distinguishes it from the other refrigerants mentioned, making it the correct choice for this question.