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Title: Optimal design of microtube recuperators for an indirect supercritical carbon dioxide recompression closed Brayton cycle

This paper presents a baseline design and optimization approach developed in Aspen Custom Modeler (ACM) for microtube shell-and-tube exchangers (MSTEs) used for high- and low-temperature recuperation in a 10 MWe indirect supercritical carbon dioxide (sCO 2) recompression closed Brayton cycle (RCBC). The MSTE-type recuperators are designed using one-dimensional models with thermal-hydraulic correlations appropriate for sCO 2 and properties models that capture considerable nonlinear changes in CO 2 properties near the critical and pseudo-critical points. Using the successive quadratic programming (SQP) algorithm in ACM, optimal recuperator designs are obtained for either custom or industry-standard microtubes considering constraints based on current advanced manufacturing techniques. The three decision variables are the number of tubes, tube pitch-to-diameter ratio, and tube diameter. Five different objective functions based on different key design measures are considered: minimization of total heat transfer area, heat exchanger volume, metal weight, thermal residence time, and maximization of compactness. Sensitivities studies indicate the constraint on the maximum number of tubes per shell does affect the number of parallel heat exchanger trains but not the tube selection, total number of tubes, tube length and other key design measures in the final optimal design when considering industry-standard tubes. In this study, the optimally designedmore » high- and low-temperature recuperators have 47,000 3/32 inch tubes and 63,000 1/16 inch tubes, respectively. In addition, sensitivities to the design temperature approach and maximum allowable pressure drop are studied, since these specifications significantly impact the optimal design of the recuperators as well as the thermal efficiency and the economic performance of the entire sCO 2 Brayton cycle.« less
ORCiD logo [1] ;  [1] ;  [2] ; ORCiD logo [3]
  1. National Energy Technology Lab. (NETL), Morgantown, WV (United States)
  2. National Energy Technology Lab. (NETL), Morgantown, WV (United States); West Virginia Univ., Morgantown, WV (United States)
  3. West Virginia Univ., Morgantown, WV (United States)
Publication Date:
Report Number(s):
Journal ID: ISSN 0306-2619; PII: S0306261918302071
Accepted Manuscript
Journal Name:
Applied Energy
Additional Journal Information:
Journal Volume: 216; Journal Issue: C; Journal ID: ISSN 0306-2619
Research Org:
National Energy Technology Lab. (NETL), Morgantown, WV (United States)
Sponsoring Org:
USDOE Office of Fossil Energy (FE)
Country of Publication:
United States
OSTI Identifier: