Overview

High Efficiency Chiller Compressor driven by a Permanent Magnet Motor on Magnetic Bearings via a Variable Speed Drive.

Customer Specifications

Johnson Controls Navy Systems (JCI), a supplier of heating, ventilation, air conditioning and refrigeration (HVAC/R) systems for use on all types of Navy vessels selected Calnetix Technologies to provide design and engineering assistance for the drive portion of its next generation, two-stage, variable speed, oil-free high-efficiency chillers. They needed a compact, highly efficient, low-maintenance and low-emission shipboard HVAC system to increase cooling capacity and performance while reducing acquisition and lifecycle costs. Improvements to mission critical cooling were required for newer/advanced weapons and command and control systems.

Solution

The HESC Chiller was developed jointly by Calnetix and Johnson Controls Navy Systems. Calnetix supplied key components for the new-generation high-efficiency super capacity (HESC) chiller system, consisting of the HESC Chiller and the HESC Variable Speed Drive. Calnetix provided Powerflux™ oil-free magnetic bearings, a Magnaforce™ sensorless high-speed permanent magnet motor, a magnetic bearing controller and a backup bearing system for the two-stage variable speed compressor at the heart of the system. Calnetix also provided the variable speed power module and controls for the HESC variable frequency drive.

Challenges

The HESC chiller had to be subjected to a sequence of four different shock impacts generated by explosive charges from varying angles and standoff distances under the water. The chiller successfully demonstrated operation during the three blasts and in standby mode for the fourth blast. The backup bearing system of the compressor absorbed the shock impacts, and the magnetic bearings recovered levitation as designed and the motor performed without any issue. The U.S. Navy’s production launch is an important validation of Calnetix’s patented magnetic bearing technology, permanent magnet motor expertise and power electronics technology.

Results

The systems are projected to save 1,000 barrels of oils per year per ship, all with no change in the system’s weight or seawater chiller capacity. The compressor has also been designed as a retrofit option to improve the performance and energy usage of more than 200 chillers already in fleet use. The next generation HESC Chillers are expected to:

  • Reduce fuel consumption by 25 percent and maintenance by at least 50 percent
  • Increase cooling density by 50 percent and reliability by at least 200 percent
  • Meet environmental objectives by cutting refrigerant leakage by 90 percent

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US Navy Ship

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U.S. Navy Floating Shock Platform (Photo courtesy of the U.S. Navy)

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High-efficiency compressor prototype undergoes shock and vibration testing at NuLabs in Annandale, New Jersey. (Photos courtesy of the U.S. Navy, YORK® Navy Systems and NuLabs)