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Thermal resistance network model for a recuperator in S-CO2 power cycle

Pandey, V and Kumar, P (2018) Thermal resistance network model for a recuperator in S-CO2 power cycle. In: 16th International Heat Transfer Conference, IHTC 2018, 10 - 15 August 2018, Beijing, China, pp. 4919-4930.

Full text not available from this repository.
Official URL: https://doi.org/10.1615/ihtc16.her.024078


Several studies have revealed that supercritical carbon dioxide (S-CO2) power cycles have the potential to attain higher cycle efficiencies than conventional steam Rankine or air Brayton power cycles. S-CO2 cycles have small footprint, offer simple layout with compact turbo machinery and heat exchangers. The design of recuperator/regenerator in the system plays a crucial role in determining cycle efficiency and performance. Therefore, a Printed Circuit Heat Exchanger (PCHE) with high effectiveness and low-pressure drop is preferable over conventional shell and tube or a tube in tube heat exchanger (HEx). Traditional procedures involving NTU and LMTD methods used for tube in tube or a shell and tube heat exchanger design do not capture the correct temperature profiles along the tube length due to nonlinear variation in physical properties of CO2 during the heat transfer process. The present paper proposes a novel thermal resistance network (TRN) model for a PCHE design which accounts for variation in properties of CO2 resulting from heat transfer between the hot and cold fluid streams in the HEx. The flow paths for hot and cold fluid streams are discretized to calculate temperature and pressure variations along the length of the heat exchanger. The model is coupled with REFPROP database to update the thermo-physical properties of hot and cold fluid streams. The lengths and hydraulic diameter of channel are iteratively varied to meet the design requirements of temperature and pressure drop across the cold and hot fluid streams. The PCHE stack comprises of multiple plates which are alternatively stacked vertically to form a counter flow HEx. The overall exposed surface area is minimized for a range of stack heights and widths to obtain a minimum PCHE foot print. The fidelity of the TRN model is demonstrated with a case study of a S-CO2 recuperator design. The inlet and outlet conditions for hot and cold streams are selected based on optimum cycle parameters for a simple recuperated S-CO2 Brayton plant developing a nominal power output of 10 MW.

Item Type: Conference Paper
Publication: International Heat Transfer Conference
Publisher: Begell House Inc.
Additional Information: The copyright for this article belongs to the International Heat Transfer Conference.
Keywords: Brayton cycle; Heat Exchanger; PCHE; Recuperator; S-CO2; Thermal resistance Network; Thermo-physical properties
Department/Centre: Division of Mechanical Sciences > Mechanical Engineering
Date Deposited: 14 Aug 2022 06:08
Last Modified: 14 Aug 2022 06:08
URI: https://eprints.iisc.ac.in/id/eprint/75741

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