EPA Section 608 Universal Certification ExamCoreMedium
A technician is installing a new commercial refrigeration system using R-404A. What is the primary reason that fractional distillation of the refrigerant can occur if the system develops a leak?
- AR-404A has a high Ozone Depletion Potential (ODP).
- BR-404A is a zeotropic blend, meaning its components have different boiling points.
- CR-404A is a pure, single-component refrigerant.
- DR-404A is a high-pressure refrigerant, which causes rapid expansion upon leakage.
Show answer & explanationAnswer & explanation
Correct answer: B. R-404A is a zeotropic blend, meaning its components have different boiling points.
R-404A is a zeotropic blend, composed of multiple refrigerants with different boiling points. When a leak occurs, the component with the lower boiling point tends to leak out faster, altering the refrigerant's composition and potentially affecting system performance, a phenomenon known as fractional distillation or 'temperature glide'.
Why the other options are wrong
- A. While R-404A does have an ODP, this characteristic does not directly explain fractional distillation during a leak.
- C. R-404A is a blend, not a pure refrigerant, making this statement incorrect.
- D. High pressure and rapid expansion are characteristics of R-404A but do not explain fractional distillation; the blend's composition is the key factor.
Zeotropic Refrigerant Blends
Zeotropic refrigerant blends are mixtures of refrigerants that have different boiling points, leading to temperature glide during phase changes and potential fractional distillation during leaks.
- Components evaporate and condense at different temperatures.
- Exhibit 'temperature glide' during phase change.
- Can undergo 'fractional distillation' if leaked, changing composition.
- Must be charged as a liquid to maintain proper composition.
Memory trick: Zeotropic means separation, different boiling points, a chemical alteration.