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US 9,869,272 B1Granted
Performance of a transcritical or supercritical CO2 Rankin cycle engine
OwnerMartin A. Stuart, Stephen Cunninghaminventors
Life of this patent
Estimating the term…
Abstract
A Rankine Expander System that converts low quality heat (heat usually at temperatures below 400 degrees Celsius) to electricity by using the properties of trans-critical CO2. The system is comprised of a compressor, an expander, three heat exchangers, and a permanent magnet alternator (PMA). It operates at pressures and temperatures that hold the CO2 above its critical point for the full cycle, and as such, attains high efficiencies even at low power. Under some conditions the efficiency can exceed 50%.
Claims23
A closed-loop CO2 system for capturing waste heat comprising:
- a heat exchanger configured for transferring heat from a lower pressure part of said closed-loop system to a higher pressure part of said closed-loop system;
- a cooler configured for receiving lower pressure CO2 from said heat exchanger for exhausting waste heat from said closed-loop system and cooling the CO2 to a temperature below the critical temperature of CO2;
- a compressor configured for compressing lower pressure CO2 received from said cooler at a temperature below the critical temperature of CO2 into higher pressure CO2 for outputting supercritical CO2 to said heat exchanger;
- another heat exchanger configured to receive higher pressure CO2 from said heat exchanger and further configured for inputting additional heat energy obtained from outside said closed-loop system into the higher pressure CO2;
- and
- a piston expander comprising a plurality of piston pairs having opposing pistons, each piston pair being associated with a associated shared expansion chamber configured to support linear travel of said pistons and configured for receiving the higher pressure CO2 to convert the higher pressure CO2 into a lower pressure CO2 to output a rotational torque to drive a load, wherein the lower pressure CO2 output by said expander is input into said heat exchanger, wherein
- at all points the lower pressure CO2 is maintained at a pressure above the critical point pressure of CO2.
4 more elements
A closed-loop CO2 system for capturing waste heat comprising:
- a heat exchanger configured for transferring heat from a lower pressure part of said closed-loop system to a higher pressure part of said closed-loop system;
- a cooler configured for receiving lower pressure CO2 from said heat exchanger for exhausting waste heat from said closed-loop system and cooling the CO2 to a temperature below the critical temperature of CO2;
- a compressor configured for compressing lower pressure CO2 received from said cooler into higher pressure CO2 for outputting supercritical CO2 to said heat exchanger;
- another heat exchanger configured to receive higher pressure CO2 from said heat exchanger and also configured for inputting additional heat energy obtained from outside said closed-loop system into the higher pressure CO2;
- and
- an expander configured for receiving the higher pressure CO2 to convert the higher pressure CO2 into a lower pressure CO2 for outputting rotational torque, wherein the lower pressure CO2 is output by said expander for input into said heat exchanger, wherein
- for the entire closed loop, said CO2 is maintained between a pressure of at least about 80 bar and a pressure of no more than about 200 bar, and further wherein
- for the entire closed loop, said CO2 is maintained at a temperature between 0° C. and 400° C., wherein
- said expander is comprised of a plurality of paired opposed pistons configured for linear travel in a common expansion chamber, wherein for each piston pair, the opposing pistons are each installed on a circumference of a different disk in a configuration provided to oscillate the different disks in opposing directions both configured to provide a rotational torque to a shaft for driving a load, with the expander being configured for generating said rotational torque through the converting of the higher pressure CO2 into lower pressure CO2.
6 more elements
A closed-loop CO2 system for capturing waste heat comprising:
- a first heat exchanger configured for transferring heat from a lower pressure part of said closed-loop system to a higher pressure part of said closed-loop system;
- a cooler configured for receiving lower pressure CO2 from said heat exchanger for exhausting waste heat from said closed-loop system and cooling the CO2 to a temperature below the critical temperature of CO2;
- a compressor configured for compressing lower pressure CO2 received from said cooler into higher pressure CO2 for outputting supercritical CO2 to said heat exchanger;
- a second heat exchanger configured to receive higher pressure CO2 from said first heat exchanger and also configured for inputting additional heat energy obtained from outside said closed-loop system into the higher pressure CO2;
- and
- an expander including a plurality of pistons arranged as pairs of opposed pistons configured to travel in a linear motion in a respective expansion chamber associated with the piston pair, each piston of said piston pair being severably installed on and driving a separate oscillating disk configured to output a rotational torque to a load, said expander being adapted to receive the heated CO2 from said second heat exchanger to convert the heated CO2 into lower pressure CO2 via an expansion process using said oscillating disks for outputting said rotational torque, wherein lower pressure CO2 is output by said expander for input into said first heat exchanger.
3 more elements
A closed-loop CO2 system for capturing waste heat comprising:
- a first heat exchanger configured for transferring heat from a lower pressure part of said closed-loop system to a higher pressure part of said closed-loop system;
- a cooler configured for receiving lower pressure CO2 from said heat exchanger for exhausting waste heat from said closed-loop system;
- a compressor configured for compressing lower pressure CO2 received from said cooler into higher pressure CO2 for outputting to said heat exchanger;
- a second heat exchanger configured to receive higher pressure CO2 from said first heat exchanger and also configured for inputting additional heat energy obtained from outside said closed-loop system into the higher pressure CO2;
- and
- an expander including a plurality of pistons arranged as pairs of opposed pistons having a common expansion chamber associated with the piston pair, each piston of said piston pair being installed on a circumference of a different disk with said pistons being configured to travel in a linear motion within a respective static expansion volume for oscillating said disks in a manner configured to generate a rotational torque for driving a load, said expander being adapted for receiving the heated CO2 from the second heat exchanger to convert the heated CO2 into lower pressure CO2 via an expansion process using said pistons for generating said rotational torque, wherein lower pressure CO2 is output by said expander for input into said first heat exchanger.
3 more elements
A closed-loop CO2 system for capturing waste heat, said system comprising:
- a first heat exchanger configured for transferring heat from a lower pressure part of said closed-loop system to a higher pressure part of said closed-loop system;
- a cooler configured for receiving lower pressure CO2 from said heat exchanger for exhausting waste heat from said closed-loop system;
- a compressor configured for compressing lower pressure CO2 received from said cooler into higher pressure CO2 for outputting supercritical CO2 to said heat exchanger;
- a second heat exchanger configured to receive higher pressure CO2 from said first heat exchanger and also configured for inputting additional heat energy obtained from outside said closed-loop system into the higher pressure CO2;
- and
- an expander configured to receive the heated CO2 to convert the heated CO2 into lower pressure CO2 for outputting rotational torque to a load, wherein the lower pressure CO2 output by said expander is input into said first heat exchanger, wherein said expander includes at least one opposing pair of pistons sharing an expansion chamber configured such that said pistons travel in a linear motion, each piston being mounted on respective disks and configured to convert energy of the CO2 for oscillating the disks about an axis of the disks with a drive shaft passing through a hole in the axis of the disks for receiving the rotational torque;
- and
- an electrical generator mechanically connected to said drive shaft in a manner configured for transmitting the rotational torque to said electrical generator, wherein
- at all points the lower pressure CO2 is maintained at a pressure above the critical point pressure of CO2.
6 more elements
A closed-loop CO2 system for capturing waste heat comprising:
- a first heat exchanger configured for transferring heat from a lower pressure part of said closed-loop system to a higher pressure part of said closed-loop system;
- a cooler configured for receiving lower pressure CO2 from said first heat exchanger for exhausting waste heat from said closed-loop system and cooling the CO2 to a temperature below the critical temperature of CO2;
- a compressor configured for compressing lower pressure CO2 received from said cooler at a temperature below the critical temperature of CO2 into higher pressure CO2 for outputting to said heat exchanger;
- a second heat exchanger configured to receive higher pressure CO2 from said first heat exchanger and further configured for inputting heat energy obtained from outside said closed-loop system into the higher pressure CO2;
- and
- an expander comprising a plurality of disks with at least one piston being mounted on each one of said disks, said pistons being configured in piston pairs each sharing a common expansion volume configured for the pistons traveling in a linear motion to drive said disks in opposing oscillating motions for rotating a shaft traveling through said disks for outputting a torque, wherein
- the expander is configured to receive the higher pressure CO2 from said second heat exchanger for converting into rotational torque, wherein lower energy CO2 output by said expander is input into said first heat exchanger for providing heat energy to said first heat exchanger and for supplying said lower pressure CO2 to said cooler.
4 more elements
Dependencies are inferred from the claim text.