In a cascade refrigerating system, the arrangement means two or more refrigerating systems are connected so that one stage's evaporator cools the next stage's condenser.

In a cascade refrigerating system, the arrangement means two or more refrigerating systems are connected so that one stage's evaporator cools the next stage's condenser.

• A. Parallel cooling loop
• B. Series cooling circuit
• C. Direct expansion network
• D. Cascade refrigerating system

Answer: (D)

Two or more separate refrigeration cycles are linked so that the evaporator of one stage cools the condenser of the next stage. This cascade arrangement allows each stage to use a refrigerant optimized for its temperature range and enables reaching much lower temperatures than a single-cycle system. The hot-stage condenser is cooled by the cold evaporator of the adjacent stage, improving overall efficiency and making very low-temperature applications feasible. This differs from a parallel cooling loop, where multiple independent loops handle loads rather than cascaded stages; a simple series cooling circuit, which would not use inter-stage condenser-evaporator cooling between stages; and a direct expansion network, which distributes refrigerant to multiple evaporators without the cascade interconnection.

Two or more separate refrigeration cycles are linked so that the evaporator of one stage cools the condenser of the next stage. This cascade arrangement allows each stage to use a refrigerant optimized for its temperature range and enables reaching much lower temperatures than a single-cycle system. The hot-stage condenser is cooled by the cold evaporator of the adjacent stage, improving overall efficiency and making very low-temperature applications feasible.

This differs from a parallel cooling loop, where multiple independent loops handle loads rather than cascaded stages; a simple series cooling circuit, which would not use inter-stage condenser-evaporator cooling between stages; and a direct expansion network, which distributes refrigerant to multiple evaporators without the cascade interconnection.