Adhesive Bonding of Aluminum and Copper in HVAC&R Applications

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Lead Performer: Oak Ridge National Laboratory — Oak Ridge, TN
Partner: 3M — Maplewood, MN
DOE Total Funding: $1,500,000
Cost Share: $167,000
Project Term: 2016-2019
Funding Type: Building Energy Efficiency Frontiers and Innovations Technologies (BENEFIT) – 2016 (DE-FOA-0001383)

Project Objective

Oak Ridge National Lab (ORNL), with its partner 3M, is developing adhesive chemistries for bonding aluminum and copper during heat exchanger manufacture, resulting in enhanced bonding and significant energy savings. Many HVAC&R systems leak refrigerants, releasing harmful greenhouse gases and decreasing the efficiency of the system. This technology targets the heat exchanger joint to maximize efficiency. The joint surface is prepped by removing contaminants and texturing the surface for enhanced bonding. Neutron Imaging then quantifies the area needing the adhesive coverage and assess how the joint should be mated and what geometry will most help reduce the mechanical stress on the joint. The brazed joint is then shrink-wrapped to prevent corrosion, and the adhesives provide electrical insulation and joint strength.

The use of this adhesive will result in the following:

  • An automated Al-Cu adhesive joint for joining aluminum microchannel head exchanger to copper tubing
  • Automated Cu-Cu adhesive U-joint technique for low-cost multi-pass copper heat exchangers
  • Automated Al-Al adhesive joint to bond manifolds to channels for new high performance microchannel header designs

Project Impact

The adhesive bonding does not require high-temperature brazing furnaces, which typically require a significant amount of power. By using this adhesive, heat exchanges have the freedom to be redesigned to be both smaller and to use less refrigerant charge, minimizing the chance of leakage. This enabling technology reduces the payback time for future high-efficiency HVAC&R equipment, a typical market barrier for energy efficient technologies. 

Contacts

DOE Technology Manager: Antonio Bouza
Lead Performer: Dr. Patrick Geoghegan, Oak Ridge National Laboratory

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