Air enters the compressor of a regenerative gas-turbine engine at 300 K and 100 kPa, where it is compressed to 800 kPa and 580 K. The regenerator has an effectiveness of 72%, and the air enters the turbine at 1200 K. For a turbine efficiency of 86%, determine (a) the amount of heat transfer in the regenerator and (b) the thermal efficiency of the cycle.