1. What are the differences between a cross-flow heat exchanger and a counter-flow heatexchanger? Which of the two is most effective if used in processes in which one of the fluidsundergoes a phase change? Justify your answer. 2. Describe the differences between a mixed cross-flow heat exchanger and an unmixed cross-flow heat exchanger. 3. In the operation of heat exchangers, what are the condition, or conditions, under which the temperature change of the hot fluid be equal to the temperature change of the cold fluid?

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