Which of the following is not considered a desirable characteristic of a good refrigerant?

In refrigeration applications, a good refrigerant is expected to possess desirable characteristics that enhance its performance and safety. These characteristics include low toxicity, which ensures that the refrigerant poses minimal health risks during normal operation, and high efficiency, allowing the system to transfer heat effectively while minimizing energy consumption.

Another important characteristic is low specific volume. A refrigerant with low specific volume is desirable because it enables more efficient and compact system design, as less space is required for the refrigerant in a given system capacity. It also contributes to better thermodynamic properties, allowing for more efficient phase changes.

Conversely, a high specific volume is not viewed as favorable because it indicates that a larger volume of refrigerant is necessary to carry out the same cooling effect. This can lead to increased system size, more complex piping and components, and possibly reduced efficiency. Therefore, selecting a refrigerant with a high specific volume could hinder the operational effectiveness of a refrigeration system, making it the least desirable characteristic among the options provided.