Design analysis of a hybrid printed circuit heat exchanger for precooling in hydrogen refueling station

Abstract

The hydrogen precooler is a critical component of hydrogen refueling stations (HRS), requiring high heat transfer efficiency, compactness, and pressure resistance. The printed circuit heat exchanger (PCHE) excels in high-pressure environments. However, in practical engineering applications, the refrigerant's operating pressure on the cold side is relatively low. Consequently, a hybrid PCHE incorporating a plate-fin structure on the cold side offers greater potential. This study evaluates the performance of three innovative hybrid PCHEs (semicircle-plain, semicircle-perforated, and semicircle-serrated) compared to conventional PCHEs (semicircle- semicircle) for 35 MPa and 70 MPa HRS using a segmented thermal design method coupled with a stress check. Channel geometrical parameters are optimized to minimize volume and pressure drop. Results show that hybrid PCHEs outperform conventional PCHEs, with the semicircle-serrated hybrid PCHE achieving the best performance. Its superior performance is attributed to the serrated fins, which enhance synergistic performance between local heat transfer coefficient and local heat transfer temperature difference and reduce thermal resistance, significantly lowering the required heat transfer area. At the optimal point, hybrid PCHE volume is reduced by 68.82 % (35 MPa HRS) and 33.33 % (70 MPa HRS), while pressure drops are reduced by 48.94 % and 83.73 %, respectively. This study provides valuable insights into optimizing PCHE designs for future hydrogen refueling infrastructure.