Spinning Scroll Compressor for H2 Recirculation
The lightweight and semi-hermetic P21H050A-BLDC-SH-SS uses spinning scroll technology to recirculate high-temperature hydrogen in SOFCs.
The P21H050A-BLDC-SH-SS is designed to boost 180 ºC, 100% humid hydrogen from 20 bara to 20.5 bara. Used to recirculate high-temperature hydrogen for a solid oxide fuel cell (SOFC) system in a weight-sensitive aerospace application, this innovative spinning scroll compressor provides 375 lpmv of hydrogen to the anode side of the SOFC in a package that weighs less than 10 kg with motor. In addition to a number of safety concerns, several engineering challenges are associated with high-temperature, high-pressure, 100% humid hydrogen as a working fluid. The P21H050A-BLDC-SH-SS is constructed using stainless steel components to mitigate hydrogen embrittlement, corrosion, and thermal expansion. Using a patented magnetic coupling configuration, the motor is separated from the working fluid with static sealing. This allows the unit to be classified as “semi-hermetic,” reducing external hydrogen leakage to acceptable and safe levels.
Aggressive weight targets are common in the aerospace industry. Weighing just under 10 kg with motor, the P21H050A-BLDC-SH-SS abandons traditional orbiting scroll technology in favor of spinning scroll technology. Also referred to as “co-rotating” scroll technology, spinning scroll technology rotates synchronous scrolls with offset centers of rotation. While the relative motion is the same as orbiting scroll technology, the synchronous motion allows spinning scroll technology to operate at much higher speeds.
While motor speeds for orbiting scroll designs are typically around 3,000 RPM, spinning scroll designs can operate over 6,000 RPM. This greatly improves performance and efficiency, without increasing the involute geometry. Additionally, several components (e.g., counterweight) are eliminated from the assembly altogether, further reducing weight and size.
As of late 2015, Air Squared has several initiatives to further research and develop spinning scroll technology along with long-term initiatives to qualify life and reliability. While the technology is primarily of interest to the aerospace industry, any application with size and weight constraints can benefit from the novel technology.