Final answer:
Zeotropic refrigerant must leave the cylinder as a liquid to maintain a consistent mixture composition, crucial for the optimal performance of the refrigeration system.
Step-by-step explanation:
The student asked why zeotropic refrigerant must leave the cylinder as a liquid. Zeotropic refrigerants are mixtures with varying compositions and boiling points. When evaporated or condensed at a constant temperature, their proportion changes owing to the different boiling points of the mixture's components. This means that if a zeotropic refrigerant were to leave the cylinder as a gas, the composition of the refrigerant would change, potentially affecting the performance of the refrigeration system.
Therefore, it is essential to ensure that the zeotropic refrigerant leaves the cylinder as a liquid. This guarantees a consistent refrigerant mixture, maintaining the optimal balance of components for the refrigeration cycle's efficiency. This is crucial for systems using zeotropic mixtures to operate effectively and maintain predictability in their cooling performance.