A refrigeration cycle apparatus includes a compressor to compress a working fluid to perform a refrigeration cycle. The working fluid contains a hydrofluoroolefin (HFO) having a double bond in a molecular structure thereof. The refrigeration cycle apparatus includes a temperature rise inhibiting unit which inhibits a temperature rise within the refrigeration cycle.

A concentric rotary fluid machine includes a first body and a second body that are rotatable relative to each other and coaxially arranged one inside the other. A plurality of gates are supported by the second body in gate pockets. Each gate pocket includes: a gate retention recess that receives a gate cylinder of a gate; a gate seal recess that receives a sealing portion of a gate; and an intervening land. The sealing portion is configured to reciprocate up and down within a corresponding gate seal recess while maintaining contact with the recess and the second body. A plurality of lobes on the first body cause the gates to swing about respective swing axes as the first body rotates relative to the second body. The lobes and the lands are configured so that a lobe forms a substantial seal against a land when in mutual radial alignment.

A pendulum slider pump may include an inner rotor connected via a plurality of pendulums to an outer rotor. The pendulums may be mounted on the outer rotor in an articulated manner, and the pendulums may respectively include a pendulum foot guiding in an associated radial groove arranged in the inner rotor. The radial grooves may each include a groove base and two circumferentially spaced groove walls. The outer rotor, the inner rotor and two pendulums adjacent in a circumferential direction may each delimit a chamber. Each pendulum foot together with the associated groove walls and the groove base may delimit a pendulum foot space. At least one pendulum foot space may be connected to the associated chamber via at least one communication channel. The at least one communication channel may open into the pendulum foot space in a region of the groove base.