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

TL;DR

This paper introduces a novel expanded microchannel heat exchanger design with a new manufacturing process, demonstrating promising preliminary results for high effectiveness and low-cost production potential across various configurations and materials.

Contribution

It presents a new expanded microchannel heat exchanger design and a continuous manufacturing technique, including a novel laser welding method, for low-cost, high-effectiveness heat exchangers.

Findings

Prototype achieved 72% effectiveness with water-to-water heat transfer.

Design allows for various flow configurations and materials.

Potential for significant cost and energy savings.

Abstract

This paper first reviews non-traditional heat exchanger geometry, laser welding, practical issues with microchannel heat exchangers, and high effectiveness heat exchangers. Existing microchannel heat exchangers have low material costs, but high manufacturing costs. This paper presents a new expanded microchannel heat exchanger design and accompanying continuous manufacturing technique for potential low-cost production. Polymer heat exchangers have the potential for high effectiveness. The paper discusses one possible joining method - a new type of laser welding named "forward conduction welding," used to fabricate the prototype. The expanded heat exchanger has the potential to have counter-flow, cross-flow, or parallel-flow configurations, be used for all types of fluids, and be made of polymers, metals, or polymer-ceramic precursors. The cost and ineffectiveness reduction may be an order of magnitude or more, saving a large fraction of primary energy. The measured effectiveness of the prototype with 28 micron thick black low density polyethylene walls and counterflow, water-to-water heat transfer in 2 mm channels was 72%, but multiple low-cost stages could realize the potential of higher effectiveness.