DESC0023791

Desire for low cost and high corrosion resistance have driven efforts to develop polymer heat exchangers in industrial heat pumps for decades; however, these approaches are typically limited by available materials with low base thermal conductivity between 0.11 and 0.35 W/mK. This low conductivity has rendered earlier attempts uncompetitive on a volumetric and performance basis to metallic heat exchangers. Attempts to improve this thermal conductivity have largely been focused on the incorporation of thermal conductivity enhancers resulting in a polymer composites. However, these attempts invariably use either expensive thermal conductivity enhancers (carbon nanotubes, boron nitride nanotubes, etc.), expensive processing techniques, or both. Mainstream Engineering Corporation proposes an alternative means to increase thermal conductivity of the base polymer without the expensive particle or processing costs. Metallic like thermal conductivities are possible with processing linear ultra-high molecular weight polyethylene (LUHMWPE) using processes analogous to processing metal sheets. The high thermal conductivity coupled with a more aggressive heat exchanger design results in the strained LUHMWPE heat exchanger having 5 times the thermal performance of COTS polymer heat exchangers while using a base material that is 2.5 times cheaper than aluminum. In Phase I we will experimentally demonstrate the high conductivity polymer by fabricating fin samples and performing an air-side heat transfer measurement. Decarbonizing industrial heat is an effective way to reduce overall greenhouse gases. While incorporating heat pumps are overall more efficient and have reasonable paybacks, more can be done. With the inclusion of inexpensive polymer-based heat exchangers, the upfront investment in these industrial heat pumps reduces improving economics. While these heat exchangers can provide improvements in a large range of applications, the best application for launch is the lumber drying industry because a) they form a very large market share of industrial heat pumps, b) the application is at moderately elevated temperatures amenable to a large range of polymers, and c) the total capacity is tenable for a first article.