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Heat rejection accounting in a multi-stage reciprocating air compressor with intercooling. Validate the energy balance statement: The total heat rejected equals (heat rejected during polytropic compression per kg of air) + (heat rejected in the intercooler per kg of air). Choose whether the statement is correct.

Difficulty: Easy

Agree
Disagree
True only for isothermal stages
True only without clearance volume

Correct Answer: Agree

Explanation:

Concept/Approach
Apply the first law to each stage and the intercooler. Heat removed from the gas occurs during the compression process (if cooled) and additionally in the intercooler between stages.

Energy balance
Q_{total out} = Σ Q_{polytropic (per kg)} + Σ Q_{intercooler (per kg)}Work input is reduced by intercooling since the specific volume at the start of the next stage is lower.

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