Mechanical-chemical energy storage

1. A method for storing energy comprising the steps of:

providing an absorbent reservoir containing a working fluid that is chemically absorbed by an absorbent;

desorbing the working fluid from the absorbent in an endothermic process;

compressing the working fluid using a reversible turbine; and

condensing the working fluid in an exothermic process and transferring the condensed working fluid to a working fluid reservoir under pressure,

wherein at least some heat generated during the condensing step is recycled to drive the desorbing step.

2. The method of claim 1 , wherein the working fluid comprises carbon dioxide, ammonia, nitrous oxide, air, or water.

3. The method of claim 2 , wherein the working fluid comprises carbon dioxide or ammonia.

4. The method of claim 3 , wherein the absorbent comprises an organic amine, an inorganic base, an activated carbon, silica gel, a zeolite, a metal organic framework, or any combination thereof.

5. The method of claim 4 , wherein the absorbent comprises an organic amine selected from monoethanolamine, piperazine, ammonia, morpholine, diethanolamine, diglycolamine, diisopropanolamine, triethanolamine, dibutylamine, methyl-diethanolamine, diethylenetriamine, or any combination thereof.

6. The method of claim 2 , wherein the working fluid comprises ammonia.

7. The method of claim 6 , wherein the absorbent comprises a metal halide salt, a mild acid, water, activated carbon, silica gel, a zeolite, or metal organic framework.

8. The method of claim 2 , wherein the working fluid comprises nitrous oxide.

9. The method of claim 8 , wherein the absorbent comprises a food oil, silicone oil, activated carbon, silica gel, zeolite, or metal organic framework.

10. The method of claim 1 , wherein the at least some heat generated from the condensing step is recycled to drive the desorbing step using a heat exchanger.

11. The method of claim 1 , further comprising a step of storing the working fluid in the working fluid reservoir in a liquid state, a critical state, or a trans-critical state.

12. The method of claim 1 , wherein the working fluid is compressed to and stored at a pressure of from about 1 bar to about 100 bar.

13. The method of claim 1 , further comprising a second compressing step after the compressing step.

14. The method of claim 1 , wherein the working fluid is expanded to a pressure of from about 0.1 bar to 10 bar.

15. The method of claim 1 , wherein the working fluid is stored at ambient temperature.

16. The method of claim 1 , further comprising a step of heating the working fluid using an outside heat source, followed by a step of expanding the working fluid.

17. A method of charging and discharging an energy storage system comprising the steps of:

charging the energy storage system comprising the steps of:

providing an absorbent storage tank containing a working fluid that is chemically absorbed by an absorbent;

desorbing the working fluid from the absorbent in an endothermic process;

compressing the working fluid using a reversible turbine;

condensing the working fluid in an exothermic process and transferring the condensed working fluid to a working fluid reservoir under pressure; and

recycling heat generated during the condensing step to drive the desorbing step; and

storing the working fluid in a working fluid reservoir under pressure; and

discharging the energy storage system comprising the steps of:

expanding the working fluid;

chemically absorbing the working fluid with the absorbent in the absorbent storage tank in an exothermic process;

recycling heat generated during the chemical absorbing step to drive the expanding step; and

storing the absorbent and the absorbed working fluid in the absorbent storage tank.

18. The method of claim 17 , wherein the working fluid comprises carbon dioxide, ammonia, nitrous oxide, air, or water.

19. The method of claim 18 , wherein the working fluid comprises carbon dioxide.

20. The method of claim 19 , wherein the absorbent comprises an organic amine, inorganic base, activated carbon, silica gel, zeolite, or metal organic framework.

21. The method of claim 20 , wherein the absorbent comprises an organic amine selected from monoethanolamine, piperazine, ammonia, morpholine, diethanolamine, diglycolamine, diisopropanolamine, triethanolamine, dibutylamine, methyl-diethanolamine, or diethylenetriamine.

22. The method of claim 18 , wherein the working fluid comprises ammonia.

23. The method of claim 22 , wherein the absorbent comprises a metal halide salt, mild acid, water, activated carbon, silica gel, zeolite, or metal organic framework.

24. The method of claim 18 , wherein the working fluid comprises nitrous oxide.

25. The method of claim 24 , wherein the absorbent comprises a food oil, silicone oil, activated carbon, silica gel, zeolite, or metal organic framework.

26. The method of claim 17 , wherein the heat generated during the condensing step is recycled drive the desorbing step using a heat exchanger.

27. The method of claim 17 , wherein the working fluid is in a liquid state, a critical state, or a trans-critical state when the working fluid is stored in the working fluid reservoir under pressure.

28. The method of claim 17 , wherein the working fluid is compressed to and stored at a pressure of from about 1 bar to about 100 bar.

29. The method of claim 27 , wherein the compressing step comprises a two-stage compression process.

30. The method of claim 17 , wherein the working fluid is expanded to a pressure of from about 0.1 bar to 10 bar.

31. The method of claim 17 , wherein the working fluid is stored at ambient temperature.

32. The method of claim 17 , further comprising a step of heating the working fluid using an external heat source prior to the expanding step.

33. The method of claim 17 , further comprising a step of directing a flow of the working fluid in a first direction during charging, and reversing the flow of the working fluid from the first direction during discharging.