Closed-cycle gas turbine vs open-cycle gas turbine: compare thermal efficiency Consider an idealized comparison where overall pressure ratio and turbine inlet temperature limits are similar. Choose how the thermal efficiency of a closed-cycle gas turbine typically compares with that of an open-cycle gas turbine.

Concept/ApproachA closed-cycle gas turbine recirculates a chosen working fluid (often helium or nitrogen) and can incorporate highly effective heat exchangers (recuperators and intercoolers) with better control of losses and leakage. For similar pressure ratio and turbine inlet temperature limits, this tends to yield a higher thermal efficiency than a simple open cycle without extensive heat recovery.

Reasons

• Ability to use a working fluid with superior properties (high specific heat, low compressor work).
• Improved heat recovery (recuperation) and reduced exhaust losses.
• Better part-load performance due to controlled boundary conditions.

Common pitfallAssuming open cycle is always better because of simplicity; in practice, closed cycles are often chosen for efficiency with heat recovery.

Final AnswerHigher efficiency