Which of the following is a characteristic of temperature glide?

• A. Fixed boiling point
• B. Variable composition during vaporization
• C. Unchanging pressure
• D. Saturated vapor state

Answer: (B)

Temperature glide refers to the phenomenon where a refrigerant mixture evaporates over a range of temperatures instead of at a single, constant boiling point. This characteristic is particularly relevant for azeotropic and non-azeotropic blends, where the composition of the mixture changes as it transitions from liquid to vapor during the vaporization process.

When a refrigerant has a temperature glide, it does not boil at a fixed temperature. Instead, as it absorbs heat and vaporizes, its composition alters, and this leads to a range of temperatures at which phase changes occur. This is significant in systems that utilize refrigerant mixtures, as it affects heat transfer and system efficiency.

The other options do not accurately represent temperature glide. A fixed boiling point suggests a substance that transitions directly from liquid to gas at a single temperature, which does not apply to substances with temperature glide. Unchanging pressure does not account for the variable interactions between different components in a refrigerant blend during vaporization. Lastly, a saturated vapor state pertains to a specific condition of a refrigerant that is fully vaporized at a given pressure and temperature, rather than describing the changes happening throughout the vaporization process influenced by temperature glide.