Which refrigerant is not used as a cooling medium in an indirect refrigeration system?

In the context of refrigeration systems, it is essential to discern the typical uses of various refrigerants. R-410A, R-134A, and Ammonia are commonly recognized as refrigerants utilized in indirect refrigeration systems.

R-410A is a popular refrigerant in residential and commercial air conditioning systems due to its efficient cooling performance and lower environmental impact compared to older refrigerants. R-134A has been widely used in applications such as automotive air conditioning and some refrigeration systems. Ammonia, though typically used in industrial applications, is also utilized in indirect refrigeration systems because of its excellent thermodynamic properties and high efficiency.

R-22, on the other hand, has faced increasing scrutiny and regulatory restrictions due to its ozone depletion potential. Although it has been used in many older systems, it is primarily being phased out in favor of more environmentally friendly alternatives. Therefore, it is less likely to be employed in new indirect refrigeration installations, which are increasingly designed to comply with modern environmental standards.

This aligns with the knowledge that while the other options are actively used as cooling mediums in various indirect systems, R-22 is on the decline and often replaced by more sustainable refrigerants, making it a less appropriate choice in current practices and developments