03. Electronics Packaging and Thermal Management

The recuperator performance used in the supercritical carbon dioxide Brayton cycle was numerically investigated. A compact printed circuit heat exchanger was adopted as the recuperator due to its capability under high-pressure operation. The effects of thermodynamic property, flow directions, flow passage configuration, and operation temperature on the heat transfer effectiveness and pressure drop of the recuperator were examined. The simulated results indicated that when the hot and cold flows are countercurrent to each other, better heat transfer effectiveness can be obtained due to the higher average temperature difference. Under the identical hydraulic diameter, it was found that the cross-sectional shape of the channel did not produce a significant effect on heat transfer effectiveness. However, the pressure drop can be reduced when the ratio of width to depth of the channel shape increases. For the effect of recuperator operation temperature, it was found that heat transfer effectiveness can be improved when the operation temperature is close to the pseudo-critical temperature of carbon dioxide due to higher thermal conductivity. Moreover, lower pressure drop can be obtained due to higher density. Finally, it was also found that the overall thermal efficiency of the Brayton cycle incorporated with a recuperator can increase by 5.2~6.5% under the recuperator operation conditions studied.