HVAC systems and methods for delivering highly efficient heating and cooling using ambient air as the working fluid. A plenum has an upstream inlet and a downstream outlet, each in fluid communication with a target space to be heated or cooled. Ambient air is drawn into the inlet at an incoming pressure and an incoming temperature. The inlet and outlet are gated, respectively, by first and second rotary pumps. A heat exchanger in the plenum transfers heat into or out of the air, provoking a change in air volume within the plenum. Work is harvested in response to change in air volume. The systems and methods can be configured to replace a traditional blower fan used to circulate the interior and exterior air. The systems and methods can be configured to implement a technique referred to as Convergent Refrigeration.

HVAC systems and methods for delivering highly efficient heating and cooling using ambient air as the working fluid. A plenum has an upstream inlet and a downstream outlet, each in fluid communication with a target space to be heated or cooled. Ambient air is drawn into the inlet at an incoming pressure and an incoming temperature. The inlet and outlet are gated, respectively, by first and second rotary pumps. A heat exchanger in the plenum transfers heat into or out of the air, provoking a change in air volume within the plenum. Work is harvested in response to change in air volume. The systems and methods can be configured to replace a traditional blower fan used to circulate the interior and exterior air. The systems and methods can be configured to implement a technique referred to as Convergent Refrigeration.

A compound engine assembly with an engine core including at least one internal combustion engine, a compressor, and a turbine section where the turbine shaft is configured to compound power with the engine shaft. The turbine section may include a first stage turbine and a second stage turbine. The turbine shaft is rotationally supported by a plurality of bearings all located on a same side of the compressor rotor(s) and all located on a same side of the turbine rotor(s), for example all located between the compressor rotor(s) and the turbine rotor(s), such that the compressor rotor(s) and the turbine rotor(s) are cantilevered. A method of driving a rotatable load of an aircraft is also discussed.

A compound engine assembly with an engine core including at least one internal combustion engine, a compressor, and a turbine section where the turbine shaft is configured to compound power with the engine shaft. The turbine section may include a first stage turbine and a second stage turbine. The turbine shaft is rotationally supported by a plurality of bearings all located on a same side of the compressor rotor(s) and all located on a same side of the turbine rotor(s), for example all located between the compressor rotor(s) and the turbine rotor(s), such that the compressor rotor(s) and the turbine rotor(s) are cantilevered. A method of driving a rotatable load of an aircraft is also discussed.

A compressor and waste heat recovery system is disclosed in which mechanical work from a prime mover along with work generated from the waste heat recovery system are used to operate the compressor. A gas producing system is heated by waste heat from operation of the compressor to produce a stream of gas used to drive a turbine. The turbine is in work communication with the compressor. In one embodiment the gas producing system is a metal hydride. An overrunning clutch can be used with the turbine. In one form multiple gas producing systems are used, one of which to emit gas while the other is used to receive and capture the emitted gas.

A fluid expander is disclosed as used in conjunction with an air compressor that is driven by a prime mover. The fluid expander is structured to extract useful work from a fluid stream and add that work to the work provided by the prime mover to the compressor. In some embodiments a clutch can be used to decouple the expander from the compressor if insufficient work is developed by the expander. A gear train can also be used to change the rotational speed prior to work being delivered to the compressor.

In at least one aspect, this disclosure relates to a wellsite pump for a well site having a wellbore penetrating a subterranean formation. The well site has a conduit to pass a wellsite fluid about the wellsite. The wellsite pump includes a housing having an intake and an outtake, at least one hydraulic motor to pump the wellsite fluid from the intake and through the outtake, at least one driver coupled to the hydraulic motor and movable therewith, and a power source. The intake is in fluid communication with the conduit, and the outtake is positioned a distance upstream of the intake. The hydraulic motor includes a rotor and a stator. The power source drives the driver and the hydraulic motor coupled thereto whereby the wellsite fluid is advance from the conduit to a location upstream therefrom.

In at least one aspect, this disclosure relates to a wellsite pump for a well site having a wellbore penetrating a subterranean formation. The well site has a conduit to pass a wellsite fluid about the wellsite. The wellsite pump includes a housing having an intake and an outtake, at least one hydraulic motor to pump the wellsite fluid from the intake and through the outtake, at least one driver coupled to the hydraulic motor and movable therewith, and a power source. The intake is in fluid communication with the conduit, and the outtake is positioned a distance upstream of the intake. The hydraulic motor includes a rotor and a stator. The power source drives the driver and the hydraulic motor coupled thereto whereby the wellsite fluid is advance from the conduit to a location upstream therefrom.

A volumetric expander (20) configured to transfer a working fluid and generate useful work includes a housing. The housing includes an inlet port (24) configured to admit relatively high-pressure working fluid and an outlet port (26) configured to discharge to a relatively low-pressure working fluid. The expander also includes first and second twisted meshed rotors (30,32) rotatably disposed in the housing and configured to exp/and the relatively high-pressure working fluid into the relatively low-pressure working fluid. Each rotor has a plurality of lobes, and when one lobe of the first rotor is leading with respect to the inlet port, one lobe of the second rotor is trailing with respect to the inlet port. The expander additionally includes an output shaft (38) rotated by the relatively high-pressure working fluid as the fluid undergoes expansion. A system for generating work using the expander in a Rankine cycle is also disclosed.

A volumetric expander (20) configured to transfer a working fluid and generate useful work includes a housing. The housing includes an inlet port (24) configured to admit relatively high-pressure working fluid and an outlet port (26) configured to discharge to a relatively low-pressure working fluid. The expander also includes first and second twisted meshed rotors (30,32) rotatably disposed in the housing and configured to exp/and the relatively high-pressure working fluid into the relatively low-pressure working fluid. Each rotor has a plurality of lobes, and when one lobe of the first rotor is leading with respect to the inlet port, one lobe of the second rotor is trailing with respect to the inlet port. The expander additionally includes an output shaft (38) rotated by the relatively high-pressure working fluid as the fluid undergoes expansion. A system for generating work using the expander in a Rankine cycle is also disclosed.