Evaporation-driven engines

Patent metadata

Field	Value
Publication number	US-10415550-B2
Application number	US-201515308122-A
Country	US
Kind code	B2
Filing date	May 8, 2015
Priority date	May 8, 2014
Publication date	Sep 17, 2019
Grant date	Sep 17, 2019

Abstract

Evaporation-driven engines are disclosed herein. An example engine can include a water source having a high humidity zone proximate the surface of the water source, a supporting structure, and a hygroscopic material disposed on the supporting structure and configured to generate mechanical force in response to a changing relative humidity. The hygroscopic material can be repeatedly exposed to the high humidity zone and removed from the high humidity zone thereby causing the hygroscopic material to generate mechanical force.

First claim

The invention claimed is:

1. An evaporation-driven engine comprising:
A water container having a shutter mechanism structurally connected to the water container and a water source having a high humidity zone proximate a surface of the water source;
a supporting structure; and
a hygroscopic material disposed on the supporting structure and configured to generate mechanical force in response to a changing relative humidity;
wherein the hygroscopic material is repeatedly exposed to the high humidity zone and removed from high humidity zone thereby causing the hygroscopic material to generate mechanical force, and
wherein the hygroscopic material is disposed alternately on a first side of the supporting structure and on a second side of the supporting structure.

2. The evaporation-driven engine of claim 1 , wherein the hygroscopic material comprises bacterial spores.

3. The evaporation-driven engine of claim 2 , wherein the bacterial spores are Bacillus subtilis spores.

4. The evaporation-driven engine of claim 1 , wherein the supporting structure is a sheet.

5. The evaporation-driven engine of claim 4 , wherein the sheet is a polyimide sheet.

6. The evaporation-driven engine of claim 4 , wherein the hygroscopic material is disposed on a first side of the sheet.

7. The evaporation-driven engine of claim 1 , further comprising a plurality of supporting structures, each supporting structure having a hygroscopic material disposed thereon.

8. The evaporation-driven engine of claim 1 , wherein the hygroscopic material is repeatedly exposed to the high humidity zone and removed from high humidity zone by moving the hygroscopic material.

9. The evaporation-driven engine of claim 1 , wherein a volume of the high humidity zone changes over time.

10. The evaporation-driven engine of claim 1 , wherein the hygroscopic material is repeatedly exposed to the high humidity zone and removed from high humidity zone by varying the high humidity zone.

11. The evaporation-driven engine of claim 1 , wherein the shutter mechanism is disposed between the surface of the water source and the hygroscopic material.

12. The evaporation-driven engine of claim 1 , wherein the hygroscopic material is disposed between the surface of the water source and the shutter mechanism.

13. The evaporation-driven engine of claim 1 , wherein the water source is a body of water.

14. An evaporation-driven engine for creation of linear motion, comprising:
a water container having a water pool and a shutter mechanism structurally connected to the water container, the shutter mechanism moveable between an open configuration, in which the water container is open and a closed configuration, in which the water container is closed; and
at least one hygroscopy driven artificial muscle (HYDRA) suspended above the water pool, each HYDRA having an extended position and a contracted position, and each HYDRA configured to transition from the extended position to the contracted position in relatively low humidity and transition from the contracted position to the extended position in relatively high humidity;
wherein the HYDRA is functionally coupled to the shutter mechanism such that when the HYDRA transitions from the extended position to the contracted position, the HYDRA causes the shutter mechanism to close, and when the HYDRA transitions from the contracted position to the extended position, the HYDRA causes the shutter mechanism to open.

15. The evaporation-driven engine of claim 14 , wherein each HYDRA comprises a support structure and a hygroscopic material disposed alternately on a first side of the support structure and on a second side of the support structure.

16. The evaporation-driven engine of claim 14 , wherein the HYDRA comprises a plurality of HYDRAs.

17. The evaporation-driven engine of claim 14 , further comprising a bistable element disposed between the at least one HYDRA and the shutter mechanism.

18. The evaporation-driven engine of claim 14 , wherein the HYDRA is functionally coupled to an electromagnetic generator.

19. The evaporation-driven engine of claim 14 , further comprising a protection layer disposed between the water and the HYDRA such that the HYDRA does not contact the water.

20. The evaporation-driven engine of claim 14 , further comprising a mechanical load configured to hold the HYDRA in tension.

21. The evaporation-driven engine of claim 14 , further comprising a floating element configured to float on the water and support the HYDRA.

22. The evaporation-driven engine of claim 14 , wherein the shutter mechanism is disposed between the surface of the water source and the hygroscopic material.

23. The evaporation-driven engine of claim 14 , wherein the hygroscopic material is disposed between the surface of the water source and the shutter mechanism.

24. The evaporation-driven engine of claim 14 , wherein the water container has a bottom, the bottom being open, and wherein the water pool is a body of water.

25. An evaporation-driven engine for creation of rotary motion, comprising:
at least one disk having a circumference region and a center;
an axle disposed through the center of the disk such that the disk can rotate freely about the center;
a plurality of hygroscopy driven artificial muscles (HYDRAs) each having a first end, a second end, each first end coupled to the circumference region of the disk such that the HYDRAs extend and contract radially relative the disk, each HYDRA having an extended position and a contracted position, and each HYDRA configured to transition from the extended position to the contracted position in relatively low humidity and transition from the contracted position to the extended position in relatively high humidity; and
a humidity chamber configured to enclose a portion of the disk such that a first subset of the HYDRAs are disposed within the humidity chamber and are in the extended position, and a second subset of the HYDRAs are disposed outside the humidity chamber and are in the contracted position;
wherein a center of mass of the disk is offset from the center of the disk due to the first subset of HYDRAs in the extended position and the second subset of HYDRAs in the contracted position, thereby causing a torque which creates rotational motion of the disk about the center and causes the first subset of HYDRAs that are disposed within the humidity chamber to rotate out of the humidity chamber and transition from the extended position to the contracted position, and the second subset of HYDRAs that are disposed outside the humidity chamber rotate into the humidity chamber and transition from the contracted position to the extended position thereby sustaining rotational motion.

26. The evaporation-driven engine of claim 25 , wherein each HYDRA comprises a supporting structure and a hygroscopic material disposed on a first side of the supporting structure.

27. The evaporation-driven engine of claim 25 , wherein the disk comprises a plurality of disks.

28. The evaporation-driven engine of claim 25 , wherein the humidity chamber comprises a paper lining, the paper lining being wetted by water.

29. The evaporation-driven engine of claim 25 , wherein the HYDRAs extend and contract radially outward from the disk.

30. The evaporation-driven engine of claim 25 , wherein the HYDRAs extend and contract radi

Assignees

• Univ Columbia

Inventors

• Chen Xi
• Goodnight Davis W
• Sahin Ozgur

Classifications

• C12N1/20

  Bacteria; Culture media therefor · CPC title

• F03G7/005

  Electro-chemical actuators; Actuators having a material for absorbing or desorbing gas, e.g. a metal hydride; Actuators using the difference in osmotic pressure between fluids; Actuators with elements stretchable when contacted with liquid rich in ions, with UV light, with a salt solution · CPC title

• F03G7/06 Primary

  using expansion or contraction of bodies due to heating, cooling, moistening, drying or the like (using thermal expansion of non-vaporising liquids F01K) · CPC title

• B01J20/22 Primary

  comprising organic material · CPC title

• F03G7/0612

  using polymers · CPC title