Performance investigation of a helium compression system driven by a revamped rolling piston type rotor compressor.

Low-temperature refrigeration is indispensable for cryogenic applications like superconductivity and helium liquefaction, and its efficiency hinges on helium compression. This study is critical as it addresses the longstanding gap of rolling piston type rotary compressors (RPTRCs) in helium compression, a key advance for diversifying cryogenic compression technologies. Currently, helium compression relies mostly on scroll or screw compressors, limiting equipment miniaturization and cost-effectiveness; RPTRCs’ poor heat dissipation and high discharge temperatures have excluded them, hindering field progress. To address these challenges, we modified an RPTRC with oil-injection cooling, optimized exhaust, and an external heat exchanger, then built an experimental setup. The tests encompassed rotational speeds ranging from 50 to 100 rps, oil injection volumes between 3.5 to 4.5 L, and inlet water temperatures of 18–24 ◦C at flow rates of 1–3 L⋅min-1. The results demonstrated that the modified RPTRC maintained a discharge temperature below 100 ◦C; specifically at a speed of 100 rps, the exhaust pressure stabilized around 27.2 bar while achieving a volumetric efficiency increase of approximately 10.5 %. Notably, using an oil volume of 4.5 L reduced the exhaust temperature by 12.3 %, although it resulted in an increase in input power by 8.8 %. Furthermore, adjusting inlet water parameters enhanced volumetric efficiency by up to 5 % due to reductions in oil viscosity. This work first validates RPTRCs for helium two-phase compression, provides critical empirical data, and expands cryogenic compressor options, significantly advancing low-temperature refrigeration research and application.