Expanded microchannel heat exchanger: design, fabrication and preliminary experimental test

摘要

This paper first reviews non-traditional heat exchanger geometry, laserwelding, practical issues with microchannel heat exchangers, and higheffectiveness heat exchangers. Existing microchannel heat exchangers have lowmaterial costs, but high manufacturing costs. This paper presents a newexpanded microchannel heat exchanger design and accompanying continuousmanufacturing technique for potential low-cost production. Polymer heatexchangers have the potential for high effectiveness. The paper discusses onepossible joining method - a new type of laser welding named "forward conductionwelding," used to fabricate the prototype. The expanded heat exchanger has thepotential to have counter-flow, cross-flow, or parallel-flow configurations, beused for all types of fluids, and be made of polymers, metals, orpolymer-ceramic precursors. The cost and ineffectiveness reduction may be anorder of magnitude or more, saving a large fraction of primary energy. Themeasured effectiveness of the prototype with 28 micron thick black low densitypolyethylene walls and counterflow, water-to-water heat transfer in 2 mmchannels was 72%, but multiple low-cost stages could realize the potential ofhigher effectiveness.