Liquid-Cooled Scroll Technology

While liquid cooling for oil-free and lubricated scroll compressor has been investigated in the past, patented liquid-cooled scroll technology from Air Squared offers the first oil-free scroll compressor design that provides effective cooling to both the fixed scroll and orbiting scroll. The patented technology allows coolant to be transferred between the fixed scroll and orbiting scroll without the use of dynamic seals.

Air-cooled scroll compressor designs are pressure-limited because the heat generated during compression causes the primary working components to thermally expand. The thermal expansion causes interference between the fixed scroll and orbiting scroll, eventually leading to mechanical failure. While the running clearance between the fixed scroll and orbiting scroll can be increased to avoid interference, this approach also decreases volumetric efficiency and pressure capability.

Liquid cooling allows for significantly more control over operating temperatures throughout the compression process. By removing heat generated during the compression process more effectively, thermal expansion is mitigated, allowing for high-pressure operation without sacrificing efficiency or reliability.

Sealed and Semi-Hermetic Configurations

Compared to air-cooled scroll compressor designs, liquid cooling offers superior isolation of working fluid to ambient and drive componentry (i.e., motor). Air-cooled compressors cool the fixed scroll and orbiting scroll with ambient air. While this approach is adequate with an open-housing compressor design, air cooling is far less effective if the compression process is fully enclosed (e.g., sealed or semi-hermetic). Liquid-cooling solves this issue by providing highly effective cooling to the fixed scroll and orbiting scroll, even if the compressor is semi-hermetically sealed.

Liquid cooling also operates independently of ambient conditions. This allows for effective cooling even if the compressor is exposed to elevated ambient temperatures – as in under-the-hood vehicle applications.

For operation with flammable gases, such as O₂ and H₂, the “independent drive” series of liquid-cooled scroll compressors are easily configured with a magnetic coupling that fully isolates the working fluid from the motor.

Drive Configurations

Air Squared offers two drive configurations for liquid-cooled scroll compressor designs.

Integrated Drive Series

The integrated drive configuration uses a liquid-cooled BLDC motor. With liquid cooling available to the motor, as well as the compressor head, liquid-cooled scroll compressors with an integrated drive configuration are more efficient and compact.

With the cooling system fully integrated with both the motor and compressor head, custom motor requirements are difficult with an integrated drive configuration. Operation with flammable gases is also not recommended, as the motor is not isolated from the working fluid.

Independent Drive Series

The independent drive configuration is ideal for customers with custom motor requirements or operation with flammable gases. The independent drive configuration removes all rotating radial loads on the motor bearings, leaving only the torque radial loads. This allows for flexibility in motor selection, as well use of a magnetic drive coupling that fully isolates the motor from the working fluid.

Cooling Loop Integration

If your application requires an independent cooling loop, Air Squared offers integration of a single-phase liquid cooling loop, which includes all necessary hardware to circulate the coolant and discharge thermal energy.

Liquid-cooled scroll technology from Air Squared has a size, efficiency, reliability, noise, and sealing advantage over air-cooled designs. With axillary components (e.g., cooling fins, fans, ducting) no longer necessary, the size and part-count of the compressor are substantially reduced. By running the coolant in close proximity to the compression process, an order of magnitude more heat can be removed during the compression process, which allows more isothermal compression for increased efficiency. The coolant also provides a thermal barrier between the compression process and bearings. This allows the bearings to run much cooler for vastly improved reliability. Because the compressor does not rely on ambient air to directly cool the fixed scroll and orbiting scroll, the compressor housing is enclosed, which offers protection against dust and debris, as well as reduced noise.

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