CREATIVE THERMAL SOLUTIONS, INC. — Department of Defense STTR Phase I: N23A-T024

Description

We propose to develop an ultra-compact refrigerant-to-water condenser heat exchanger (HX) using a generative design (GDA) and additive manufacturing (AM). The condenser HX will use fresh water at 25 °C to remove 50 kW of heat from condensing R134a. We will demonstrate the use of generative design to identify high performing three-dimensional (3D) designs with optimal surface shapes. The designs will exploit complex 3D geometries that are possible using AM, providing high heat transfer performance not possible with conventional designs. A key innovation will be for the 3D designs to be tailored for each region of the HX device, enabling true 3D optimization. The HX will be produced in a commercially available AM metal that could potentially be scaled for end-use applications. The proposed Phase 1A project (6 months, $140K) will develop a GDA to design the 50 kW heat exchanger and validate the design using finite element simulations, fabricate and test a 5 kW component to demonstrate feasibility, and perform a preliminary manufacturing and cost analysis. An optional Phase 1B project (6 months, $100K) will further refine the design with innovative concepts for design improvements, consider automated manufacturability analysis as part of the generative design, and perform further testing and analysis. The proposed project is a collaborative effort between Creative Thermal Solutions Inc., a leading heat exchanger technology company, and University of Illinois Urbana-Champaign, one of the university leaders on AM HX development. The proposed project leverages previous work from our team on GDA for AM, condensation heat transfer, and the engineering design of condenser HXs. The team has previously shown that GDA coupled with AM can provide order-of-magnitude improvements in heat exchanger performance while also providing a significant reduction in pressure drop. Building on this previous work, we propose several key innovations for the development of the 50 kW AM HX. First, we will use generative design to find surface shapes that are optimized for the heat transfer and fluid flow conditions within the different regions of the HX device. Second, we will allow for changing cross-sectional area of the flow regions and changing surface shapes in the flow direction, to exploit 3D optimization and focus on the refrigerant side where the fluid density and heat transfer change dramatically along the flow. Third, we will use GDA to search the design space for the best combinations of HX length, width, mass flow rates. This global optimization method will allow designers to select different optimization functions, for example to create the lowest pressure drop for a given mass flow rate, or to create the highest power density for a given pressure drop.