Compact Heat Exchanger for the Stringent Operating Conditions of Gen3 CSP Systems

Gen3 Concentrating Solar-Thermal Power (CSP) systems have been designated as one of the most promising solutions for grid scale renewable energy, but wider adoption remains limited by the prohibitively high cost of components and system inefficiencies. For CSP, supercritical CO2 (sCO2) Brayton cycles provide a significant opportunity to improve system efficicency but the heat exchanger components, required for conversion of thermal energy to electricity, remains a critical technology gap. Specific challenges include the identification of robust materials for the extreme environment, scalable cost of materials and fabrication methods, and understanding the design tradeoffs and challenges of using sCO2 as a working fluid, all of which affect heat exchanger size, performance and reliability. This grant application proposes to develop a fundamentally new form of ultra-compact heat exchanger that directly addresses the cost and technology requirements for sCO2 Brayton cycles in next-gen CSP systems, adapted from a new technology developed for lower temperatures and pressure applications. The proposed work will provide the needed solution for low cost, reliable and durable ultra-compact, high temperature and high pressure heat exchangers to revolutionize the economic viability of next gen solar energy applications. The technical objectives for this Phase I SBIR will focus on vetting and integrating novel alloys into a proprietary, and fundamentally new heat exchanger technology for next-gen CSP applications with sCO2 Brayton cycles. The project approach is to adapt the heat exchanger design parameters for the stringent operating conditions of CSP while minimizing the volume of material required for fabrication and using an automated, high-speed, low-cost fabrication method to reduce the cost of the heat exchanger while meeting performance and durability requirements in a compact footprint. The primary technical questions that will be answered in Phase 1 is: what design parameters are required and materials can be used to fabricate the heat exchanger, providing the durability and reliability required for the application, while also delivering a cost-effective solution that meets or exceeds the cost and performance targets. Project tasks include 1) modelling and simulating design requirements and predicting performance, 2) analyzing materials for high temperature and high pressure operation, 3) selecting materials suitable for operating conditions and fabrication methods, 4) testing fabrication methods 5) validating the hydraulic performance, and 6) performing a detailed cost analysis with a proposal for Phase II. In Phase II, a prototype high temperature high pressure heat exchanger will be developed and tested with next- gen CSP system fluids and a detailed plan for commercialization will be developed. High temperature and high pressure heat exchangers represent a niche market, however, a new, reliable lowest cost product could capture a significant share of the existing market. In the near term, there is an existing and growing commercial market for high temperature and high pressure heat exchangers across a wide range of industrial applications including oil and gas and chemical processing which will provide a point of entry for the novel heat exchanger into established markets.