An improved HVAC vent is disclosed. The vent may include an air turbine positioned within a passageway for selectively enabling and preventing airflow. In use, the air turbine is selectively operable between first and second states. In the first state, the air turbine may be freely rotatable, via the airflow, so that the received airflow can move through the passageway. In the second state, rotation of the air turbine is controlled or prevented so that the received airflow is inhibited or substantially inhibited from moving through the passageway. The vent may also include a motor. In use, the motor may act an energy generator and as an active brake so that in the first state, rotation of the air turbine is used to charge a power storage unit, and in the second state, the motor limits rotation of the air turbine.

A waste heat recovery system for recovering waste heat of in internal combustion engine includes a turbine expander. The turbine expander includes a turbine blade, a shaft coupled to and rotatable by the turbine blade, and a nozzle assembly. The nozzle assembly includes a nozzle block disposed about the shaft and adjacent the turbine blade, a first nozzle component coupled to the nozzle block, and a second nozzle component coupled to the nozzle block. The first nozzle component defines a first nozzle having a first geometrical configuration. The second nozzle component defines a second nozzle having a second geometrical configuration that is different from the first geometrical configuration. The waste heat recovery system also includes a flow control device in fluid communication with the turbine expander. The waste heat recovery system further includes a controller in communication with the flow control device.

A turbomachine (105) configured to compress supercritical carbon dioxide is shown. The turbomachine comprises, in fluid flow series, an inlet (201), an inducerless radial impeller (202) having a plurality of blades, and a fully vaneless diffuser (203). The radius of the inlet (r.sub.0) is from 25 to 50 percent of the radius of the impeller (r.sub.2).

Provided is an improved architecture for rotary kinetic fluid motors and pumps, in which working fluid gains or loses pressure by flowing through an alternating sequence of radial-flow impellers and radial-flow fluid vortices, the impellers and fluid vortices all rotating around a single axis and in a common direction at staggered speeds, each vortex being the product of rotating fluid that is flowing radially through a bladeless annular volume.

Provided is an improved architecture for rotary kinetic fluid motors and pumps, in which working fluid gains or loses pressure by flowing through an alternating sequence of radial-flow impellers and radial-flow fluid vortices, the impellers and fluid vortices all rotating around a single axis and in a common direction at staggered speeds, each vortex being the product of rotating fluid that is flowing radially through a bladeless annular volume.

A pneumatic engine, comprising: a rotating outer ring (1), an intermediate shaft (2), a direct drive power core (3), and left and right baffles (4) and (5) where the rotating outer ring (1), the direct drive power core (3), and the left and right baffles (4) and (5) are coaxially provided on the intermediate shaft (2), the rotating outer ring (1) is integrally connected to the left and right baffles (4) and (5) to engage with the intermediate shaft (2) via a bearing, and a closed space is formed, the intermediate shaft (2) is provided with a master air inlet (21) and a master air outlet (22), the direct drive power core (3) is provided with a logarithmic spiral line runner, multiple drive grooves (11) are provided on an inner ring surface of the rotating outer ring (1). The pneumatic engine has a simple structure, high transmission efficiency and strong endurance.

A turbomachine (105) configured to compress supercritical carbon dioxide is shown. The turbomachine comprises, in fluid flow series, an inlet (201), an inducerless radial impeller (202) having a plurality of blades, and a fully vaneless diffuser (203). The radius of the inlet (r.sub.0) is from 25 to 50 percent of the radius of the impeller (r.sub.2).

A turbomachine (105) configured to compress supercritical carbon dioxide is shown. The turbomachine comprises, in fluid flow series, an inlet (201), an inducerless radial impeller (202) having a plurality of blades, and a fully vaneless diffuser (203).

A turbine housing assembly seal can include a cylindrical portion that defines an opening having an axis where the cylindrical portion is disposed at a cylinder radius from the axis; a lower edge disposed at a lower edge radius that exceeds the cylinder radius; an sloped annular portion that extends radially inwardly from the lower edge; a lower bend that extends from the sloped annular portion to a lower axial position of the cylindrical portion; an upper bend that extends from an upper axial position of the cylindrical portion; and an upper edge that extends radially outwardly from the upper bend to an upper edge radius that exceeds the cylinder radius and that is less than the lower edge radius.

A turbine housing assembly seal can include a cylindrical portion that defines an opening having an axis where the cylindrical portion is disposed at a cylinder radius from the axis; a lower edge disposed at a lower edge radius that exceeds the cylinder radius; an sloped annular portion that extends radially inwardly from the lower edge; a lower bend that extends from the sloped annular portion to a lower axial position of the cylindrical portion; an upper bend that extends from an upper axial position of the cylindrical portion; and an upper edge that extends radially outwardly from the upper bend to an upper edge radius that exceeds the cylinder radius and that is less than the lower edge radius.