Thermal performance of heterogeneous PCHE for supercritical CO2 energy cycle

The supercritical CO2 (S-CO2) energy cycles are gaining increasing attention due to its high efficiency in a compact footprint and ability to utilizing various heat sources. The printed circuit heat exchanger (PCHE) is regarded an essential component in the S-CO2 cycle due to its high compactness and structural rigidity. In this study, an innovative type of PCHE, the heterogeneous type PCHE is proposed and its thermal performance is investigated numerically. The effect of channel sizes of heat source fluid and heat sink fluid, the spacing between the channels, and the channel cross-sectional shape on the thermal performance is analyzed. The results indicate that the thermal performance of the PCHE decreases monotonically as the either of channel size increases, because the flow velocity decreases subject to fixed mass flow rate condition. The spacing between the channels is shown to hardly affect the thermal performance of the PCHE. However, the spacing significantly affects the structural reliability of the PCHE. The channel cross-sectional shape also does not have significant effect on the thermal performance, provided that the hydraulic diameter of the channel remains constant. (C) 2016 Elsevier Ltd. All rights reserved.