An analytical methodology to evaluate thermalhydraulic performance of compact heat exchangers, accounting for heat loss

For the successful deployment of Advanced High Temperature Reactors (AHTRs), effective and robust high-temperature heat transport systems are essential. Printed circuit heat exchangers (PCHEs) are strong candidate heat exchangers for the intermediate or secondary loop of AHTRs due to their high power density and compactness. Recently, Idaho National Laboratory has been developing the Advanced Reactor Technology Integral System Test (ARTIST) facility to evaluate the thermal-hydraulic performance of PCHEs. Experimental data from that facility will be used as the basis for validation of CFD simulations for PCHEs. This paper describes an analytical methodology to evaluate the thermal-hydraulic performance of PCHEs from experimental data, accounting for extraneous heat losses. In order to correctly compare experimental data with the simulation results, any heat losses from the heat exchanger must be determined and incorporated. We employed the experimental data from straight-channel PCHEs with high-temperature, high-pressure helium. The experiments were performed at the High-Temperature Helium Test Facility (HTHF) at the Ohio State University. The heat exchanger effectiveness results, determined without accounting for heat loss, exhibited significant data scatter whereas the corrected data showed good agreement with the effectiveness evaluated by ϵ-NTU method when the developed methodology is employed. This methodology could be used for the improved evaluation of the heat exchanger performance, even though the heat exchanger heat loss was not directly quantified experimentally.