What does the term 'zeotropic' refer to in refrigerants?

• A. Refrigerant mixtures used in industrial processes
• B. Blends of two or more different chemical compounds
• C. Refrigerants that remain liquid under all conditions
• D. Single chemical refrigerants with high efficiency

Answer: (B)

The term 'zeotropic' specifically refers to blends of two or more different chemical compounds, particularly in the context of refrigerants. Unlike azeotropic mixtures, which have a constant boiling point and vapor composition, zeotropic mixtures change in composition as they evaporate or condense. This means that in a zeotropic blend, the components can vaporize and condense at different rates, leading to variations in temperature and pressure during the phase change process.

These characteristics make zeotropic refrigerants advantageous in practical applications, as they can provide better performance and efficiency in refrigeration systems by allowing for more precise temperature control. Understanding the nature of zeotropic mixtures is crucial for HVAC professionals, especially in selecting and handling refrigerants in compliance with regulations.