Energy harvesting, storing, and conversion utilizing shape memory activation
A system for and method of harvesting, storing and converting naturally occurring energy, includes exposing an active material, and more preferably a shape memory element to an ambient activation signal or condition, harvesting a portion of the energy by pseudoplastically straining or superelastically deforming the element, storing the energy by causing a change in the element and/or engaging a locking mechanism, and converting the energy by exposing the mechanism to an activation signal and/or otherwise releasing the mechanism.
1. A method of harvesting, storing and converting energy from a natural energy source, utilizing an active material energy storage element, said method comprising the steps of:
exposing the element to an activation signal produced by the energy source and having energy;
harvesting the energy by reversibly changing and activating the element, as a result of exposure to the signal over a first period, so as to achieve a modified condition;
storing the energy by directly engaging and mechanically locking the element in the modified condition; and
converting the stored energy to work over a second period spaced from the first period, by occluding the element from the signal and unlocking the element.
2. The method as claimed in claim 1 , wherein the storing element comprises a psuedoplastically strained shape memory alloy in its martensite phase, the element is connected in series to a biasing element, and causes the biasing element to store energy in the modified condition.
3. The method as claimed in claim 2 , wherein the storing element presents a spring having differing activated and deactivated moduli.
4. The method as claimed in claim 3 , wherein the biasing element further presents a spring made of a shape memory polymer having a deactivated modulus greater than the activated and deactivated moduli of the storing spring, so as to present a reverse actuator, and an activated modulus less than the deactivated and greater than the activated modulus of the storing spring, so as to selectively convert energy when deactivated.
5. The method as claimed in claim 1 , wherein a locking mechanism selected from the group consisting of latches, pawls, and ratcheting mechanisms engages the storing element, so as to retain the element in the modified condition.
6. The method as claimed in claim 5 , wherein the locking mechanism is a pawl comprising SMP in its low temperature high modulus phase, and energy is released as a result of heating the pawl, so as to change the SMP to its low modulus phase.
7. The method as claimed in claim 5 , wherein the locking mechanism further includes an SMA wire attached to the latch, pawl, or ratcheting mechanism, and heating the wire further enables the energy to be released.
8. The method as claimed in claim 5 , wherein the locking mechanism includes a one-way ratcheting mechanism having a gear wheel comprising SMP, and energy is converted as a result of heating the wheel and transitioning the SMP.
9. The method as claimed in claim 1 , wherein the signal is produced by sunlight or earth-heat, and the storing element is exposed to water or ambient air conditions to convert the energy.
10. The method as claimed in claim 9 , wherein the storing element is drivenly coupled to a sun umbrella, and is operable to effect the self-opening or self-closing of the umbrella when activated, and the umbrella includes a locking mechanism configured to store the energy.
11. The method as claimed in claim 10 , wherein the signal is produced by centrifugal force, the storing element is attached to the flywheel of a vehicle, and operable to relocate flywheel mass, so as to serve as a torque booster.
12. The method as claimed in claim 1 , wherein the signal is produced by a force, gravity or weight.
13. The method as claimed in claim 1 , wherein the storing element is coupled to a Sterling-motor.
14. The method as claimed in claim 1 , wherein the element consists of material selected from the group consisting essentially of shape memory alloys, shape memory polymers, shape memory ceramics, electroactive polymers, piezoelectric composites, and magneto and electro-rheological composites.
15. A method of harvesting naturally occurring energy utilizing a shape memory alloy element in an initial unstrained Martensite state, said method comprising the steps of:
exposing the element to a naturally occurring condition having energy;
harvesting and storing a portion of the energy by autonomously absorbing said portion with, so as to pseudoplastically strain the element over a first period; and
converting the portion of energy to work by exposing the element to an activation signal over a second period spaced from the first period.
16. The method as claimed in claim 15 , wherein the condition is selected from the group consisting of an air flow, water flow, seismic earth displacement, and the rotation of a body.
17. The method as claimed in claim 15 , wherein the signal is produced through direct solar loading, or focused solar radiant energy.
18. A method of harvesting naturally occurring energy utilizing a shape memory alloy element in an initial high modulus Austenitic phase, said method comprising the steps of:
exposing the element to a naturally occurring condition having energy;
harvesting and storing a portion of the energy by autonomously straining the element, so as to cause a stress induced phase change to the Martensitic phase, absorbing said portion with, so as to superelastically strain, the element and locking the element when strained with a locking mechanism over a first period;
converting the portion of energy to work by releasing the mechanism over a second period spaced from the first period.
19. The method as claimed in claim 18 , wherein the element is configured so as to change from one of two stable states of a bi-stable mechanism.