Performance analysis of printed circuit heat exchanger for supercritical carbon dioxide and water

Abstract

Printed circuit heat exchanger could be used as pre-cooler in the supercritical carbon dioxide (S-CO2) Brayton power cycle. Due to the drastic variations of S-CO2 properties in pre-cooler, segmental design method is used to investigate the thermal-hydraulic performance of PCHE. When the heat duty is given, the local heat transfer entropy generation number has extreme value, which appears near the intersection point of the heat capacity flow rates of both sides. In addition, the local and total entropy generation mainly depend on the local and total heat transfer entropy generation, and the flow imbalance increases entropy generation, especially under conditions of the higher local heat capacity flow rate of water.

Design Evaluation for a Finned-Tube CO2 Gas Cooler in Residential Applications

“…On the refrigerant-side, the Gnielinski correlation [26] was used to calculate the Nusselt number: (13) which is valid in the range of 2300 < Re b < 10 6 .…”

“…They described the variations of local heat transfer coefficient in the cooling process in the direction of the flow and proposed a more accurate heat transfer correlation. Zhang et al [13] evaluated the performance of a printed circuit heat exchanger for cooling CO 2 with water. The analysis concluded that rapid variations in the thermodynamic properties of supercritical CO 2 increase entropy generation and therefore, to optimize the second law efficiency of the investigated heat exchanger, higher CO 2 mass flow rates should be used.…”