ANS:C - 1

The capacity of an evaporator is usually defined by the rate at which it can evaporate a certain amount of liquid under given conditions. In a multiple-effect evaporator, the vapor generated in one effect is used as the heating medium in the subsequent effect(s), which improves overall efficiency. The capacity of a multiple-effect evaporator is typically higher than that of a single-effect evaporator due to the reuse of vapor energy. If we assume that the terminal conditions (inlet and outlet temperatures, etc.) and the heat transfer area are the same for both single and triple effect evaporators, then the ratio of their capacities would directly correspond to the number of effects. In this case, the ratio of the capacities of a single-effect evaporator to a triple-effect evaporator would be: 13=0.3331​=0.33 So, the correct answer is 0.33.