Rotary compressor-expander systems and associated methods of use and manufacture, including two-lobed rotor systems

A rotary displacement system comprising:

• a chamber housing having a pressure-modifying chamber with a first port and a second port;
• a first passageway in fluid communication with the chamber via the first port;
• a second passageway in fluid communication with the chamber via the second port;
• a shaft positioned within the chamber housing and rotatable relative to the chamber housing about a rotational axis;
• a rotor carried by and rotatable relative to the shaft and having a rotor periphery;
• and
• a variable geometry seal coupled to the chamber housing between the first port and the second port and sealably engaged with the rotor periphery.

A rotary displacement system comprising:

• a chamber housing having a pressure-modifying chamber with a first port and a second port;
• a first passageway in fluid communication with the chamber via the first port;
• a second passageway in fluid communication with the chamber via the second port;
• a shaft positioned within the chamber housing and rotatable relative to the chamber housing about a rotational axis;
• a rotor positioned within the pressure-modifying chamber and comprising no more than two lobes, wherein the rotor is carried by and rotatable relative to the shaft, and wherein the rotor is alternately operable in a first mode in which flow is provided from the second passageway to the first passageway via the chamber and in a second mode in which flow is provided from the first passageway to the second passageway via the chamber;
• a fluid storage volume in fluid communication with the pressure-modifying chamber via the first and second passageways;
• and
• a controller coupled to the shaft, the controller being programmed with instructions that, when executed, reverse a rotation direction of the shaft.