Design and optimization of heat exchanger in coaxial pulse tube cryocooler working above 100 K

•An exergy analysis of slit, circular hole, and copper mesh heat exchangers has determined that slit heat exchangers are superior.•A cooling power of 50 W@185.3 K was obtained at a no-load temperature of 90.4 K with an input power of 200 W, a charging pressure of 2.4 MPa and a reject heat temperature of 300 K.•At an input work of 200 W, a charging pressure of 2.8 Mpa and a cold head temperature of 165 K, the specific Carnot efficiency was 16%. Compared to the highest efficiency of Case 1 (14.3%), the cooling efficiency is increased by 11.87%.