Centrifugal compressor and heat pump comprising

A lightweight, large volume centrifugal compressor for use in mechanical vapor compression systems, especially water vapor compression systems in heat pump installations, said compressor being capable of handling a vapor flow rate of about 300-400 m.sup.3 /sec, providing a compression ratio of about 1:3 and sustaining mechanical stresses such as occur at tip speeds of about 500 m/sec;

• said compressor comprising a propeller-like rotary member consisting of a frusto-conical hub and a plurality of curved blades made of a lightweight material, each being secured to said hub along a longitudinal curved line and radially extending therefrom;
• each pair of adjacent blades being interconnected by a bridging membrane member of a lightweight material curvingly extending from the roots of the leading edges (as defined herein) of said adjacent blades to the tips of the rear edges of the blades (as defined herein);
• said rotary member being driven by a shaft passing through the center of a stationary circular back plate bounding said rotary member at the rear;
• said rotary member being encompassed within a closely fitting shroud, so that curved vapor flow channels are defined between each said pair of blades, their associated membrane member, and the shroud.