World-first micro-channel heat exchanger optimized for low-density refrigerants

Friday, April 30, 2021

Danfoss has expanded its popular range of microchannel heat exchangers, with a new version optimized for use with low-density, low-GWP refrigerants like R1234ze and R515B.

The new, world-first technology solves a key design challenge for OEMs transitioning to ultra-low GWP refrigerants such as R1234ze and R515B—especially in large air-cooled chillers using screw and centrifugal compression.

Typically, the low density of these refrigerants makes system performance highly sensitive to pressure drops.

But thanks to optimized micro-channel tube geometry, the new, optimized microchannel heat exchangers (MCHEs) provide the ideal balance between maximum heat rejection and internal refrigerant pressure drop.

As a result, OEMs can realize a 20% reduction in refrigerant pressure drop at the component level and transition more easily to low-GWP, low-density refrigerants.
This change marks over a decade of innovation in MCHE as the key technology for high-efficiency systems that require a lower refrigerant charge. It enables OEMs to realize CO2 reduction goals while reaping all the benefits of customized MCHEs:

  • High energy performance
  • Lower refrigerant charge
  • Sustainable build

These new MCHEs also mark a step forward for Danfoss in its broader roadmap for tackling energy efficiency and refrigerant change.

The ultra-low GWP refrigerant R1234ze is an increasingly popular choice for HVACR applications, as it’s widely available with a GWP below 5 and has the lowest flammability of all A2L-rated refrigerants. R515B is also growing in popularity, as it has an AR5 GWP of 299 and an ASHRAE A1 safety classification.

Jeff Tucker, Head of Micro Channel at Danfoss, explains: "The climate crisis is the biggest challenge we face, and the innovations we’re seeing today will play a crucial role in our global future. So we’re really excited to be creating new opportunities for our customers to transition to low-GWP, low-density refrigerants—and see the impact that has on CO2 emissions and energy efficiency."

"While the new MCHE technologies mark a big step towards this goal, it is not new to Danfoss, adds Luigi Zamana, Danfoss global senior director of Marketing A/C and Heat pumps. We were pioneering with Danfoss Turbocor back in 2014, then we have developed and qualified a wide portfolio of expansion valves, sensors, and line components. With the potential of these medium-density refrigerants, we’re not stopping there. We will be introducing a range of large scroll compressors. So expect more exciting new developments soon."

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