A: replaces part of the high temperature heat that must be paid for with part of the low temperature heat that is normally rejected to the environment.

B: replaces part of the low temperature heat that is normally rejected to the environment with the high temperature heat that must be paid for.

How is the cycle efficiency for a regenerative gas turbine engine defined?

As the amount of heat that is transferred in the regenator increases, the cycle efficiency

Decreases

Increases

The amount of heat that is transferred in the regenerator, q_REGEN, is equal to h_X - h₂. An ideal regenerator transfers the maximum amount of heat possible, defined by the conditions T_X = T₄ and, for an ideal gas, h_X = h₄. The regenerator effectiveness is used to relate the actual heat transferred in a regenerator to the maximum heat transfer possible.

Typical regenator effectivenesses range from 60 to 80%. Further increases in effectivenesses are typically not economical due to the large capital expenditures required to achieve these increases.