Centrifugal compressor for use with low global warming potential (gwp) refrigerant

A centrifugal compressor for use with a low global warming potential (GWP) refrigerant, the centrifugal compressor comprising:

• a casing having a first inlet portion and a first outlet portion;
• a first impeller disposed between the first inlet portion and the first outlet portion, the first impeller being attached to a first end of a shaft that is rotatable about a rotation axis, the first impeller being equipped with first blades having a fully nonlinear shape in a quasi-orthogonal cross-sectional view, a hub-side blade angle delta of each of the first blades from a hub portion of the first impeller to a mid-span position of the first blade varying along a streamwise direction such that the hub-side blade angle delta is largest at a position closer to a leading edge of the first blade than to a trailing edge of the first blade;
• a motor arranged inside the casing to rotate the shaft in order to rotate the first impeller,
• the casing being configured such that the low global warming potential (GWP) refrigerant enters the impeller from the first inlet portion along an axial direction of the first impeller and exits the first impeller to the first outlet portion in a radial direction of the first impeller.