This study was focused on two phase flow of refrigerant R134A over an array of micro pin fins heat sink in a once-through refrigerant circuit. In this study we tried to establish the main parameters affecting two phase flow in micro pin fins i.e. mass flow, heat power density, base temperature and pressure differences. We suggested a simple test configuration for measuring all necessary parameters. Test results show that we can dissipate more than 300 W/cm 2 in a reasonable base plate temperature which correlate to other work done in this area.
