Scaled-up Diffusion bonded Heat Exchanger for Supercritical CO2 Applications

Brayton-cycle sCO2 power cycles have the potential to increase the efficiency of stationary power generation above 50% as discussed in the 2015 Quadrennial Technology Review published by the DOE. However a critical bottleneck for the commercialization of this system is the lack of compatible large-scale and economically viable recuperators, which transfer heat between two sCO2 streams. Current state-of-the-art printed circuit heat exchangers (“PCHEs”) are diffusion bonded to withstand the extreme operating temperature and pressure while providing a large surface area-to-volume ratio for the necessary heat transfer between the streams and small approach temperatures. But conventional PCHE also has one major disadvantage in the limitation of stream flow design, which results in more solid metal volume adding to weight and cost of the exchanger and reducing its economic viability as well as that of the Brayton-cycle power system. CompRex, LLC (“CompRex”) seeks to address this problem with its diffusion bonded ShimRex®-ACE heat exchanger, a PCHE incorporating CompRex’s proprietary compact technology, which not only increases heat exchange efficiency by at least 25% and but also reduces footprint by at least a factor of 10 compared to traditional shell-and-tube solutions of the same capacity and by 15-20% compared to other currently available PCHE solutions. As a result, CompRex’s solution can significantly lower both capital and operating expenses for Brayton- cycle sCO2 power systems. CompRex has already demonstrated its technology and ability to deliver with a pilot-scale compact heat exchanger to Naval Nuclear Laboratory for performance testing with sCO2. Successful scale up of CompRex’s technology will provide a competitive and suitable solution for the Department of Energy's Supercritical Transformational Electric Power (STEP) program’s 10 MWe system as well as other Brayton-cycle commercialization efforts.The objective of this phase I project is to derisk and establish best practices in the manufacturing process for the scaled-up ShimRex®-ACE heat exchanger. CompRex will explore and demonstrate the techniques required to manufacture the commercial scale diffusion bonded core block and cost-effectively join individual diffusion-bonded cores into a larger block meeting ASME BPV Code requirements.