Methods and means for storing energy

• US 4,227,374 A
• Filed: 10/20/1978
• Issued: 10/14/1980
• Est. Priority Date: 10/20/1978
• Status: Expired due to Term

• Current Assignee: Alan J. Oxley
• Original Assignee: Alan J. Oxley
• Inventors: Oxley, Alan J.
• Primary Examiner(s): Swisher, S. Clement
• Application Number:
  US05/956,411
• Time in Patent Office: 725 Days
• Field of Search: 60/659, 60/652, 60/651, 60/671, 60/516
• US Class Current: 60/651
• CPC Class Codes: F01K 3/00 Plants characterised by the use of steam or heat accumulators, or intermediate steam heaters, therein regenerating exhaust steam F01K19/00
• CPC Class Codes: F02G 1/00 Hot gas positive-displacement engine plants
• CPC Class Codes: F25J 2240/70 Steam turbine, e.g. used in a Rankine cycle
• CPC Class Codes: F25J 2245/50 the recycled stream being oxygen
• CPC Class Codes: F25J 2260/30 Integration in an installation using renewable energy
• CPC Class Codes: F25J 2260/44 using nitrogen for cooling purposes
• CPC Class Codes: F25J 2270/90 External refrigeration, e.g. conventional closed-loop mechanical refrigeration unit using Freon or NH3, unspecified external refrigeration
• CPC Class Codes: F25J 3/04278 using external refrigeration units, e.g. closed mechanical or regenerative refrigeration units
• CPC Class Codes: F25J 3/04521 Coupling of the air fractionation unit to an air gas-consuming unit, so-called integrated processes combined plants, e.g. engine plant combined with an industrial process F01K23/064; gas-turbine plants supplying working fluid to a chemical process F02C6/10
• CPC Class Codes: F25J 3/04533 for the direct combustion of fuels in a power plant, so-called "oxyfuel combustion"
• CPC Class Codes: F25J 3/04563 Integration with a nitrogen consuming unit, e.g. for purging, inerting, cooling or heating
• CPC Class Codes: F25J 3/046 Completely integrated air feed compression, i.e. common MAC
• CPC Class Codes: F25J 3/04836 Variable air feed, i.e. "load" or product demand during specified periods, e.g. during periods with high respectively low power costs F25J3/0483 takes precedence

Abstract

A method is disclosed for storage of energy produced at a conventional power station and release of said energy when subsequently required. The method comprises using the energy to refrigerate and liquefy atmospheric nitrogen and oxygen, storing the liquid gases at substantially below atmospheric temperature and subsequently using cold liquid gas, in combination with a source of heat at or above atmospheric temperature, to drive a closed cycle heat engine and yield mechanical energy. Auxiliary open and closed cycle heat engines are added to yield further mechanical energy and so utilize the full energy potential of the cold liquid gases.

Claims

1. A plant including means for storing energy and subsequently releasing said energy when required, said means comprising:

refrigeration means, responsive to said energy, for refrigerating gas and liquefying said gas at substantially below atmospheric temperature;

storage means for storing said liquefied gas at substantially below atmospheric temperature;

a closed cycle heat engine having an upper temperature end and a lower temperature end;

means for utilising said liquefied gas to maintain said

lower temperature end at substantially below atmospheric temperature and means for maintaining said upper temperature end at not significantly below atmospheric temperature, thereby driving said heat engine and yielding mechanical energy, said engine including a working fluid independent of said liquefied gas.

2. The plant in claim 1 wherein said stored liquefied gas comprises nitrogen and oxygen in any proportions and is used to maintain said lower temperature end of said closed cycle heat engine at below -118°

C.

3. The plant in claim 1 wherein means are provided to maintain said upper temperature end of said closed cycle heat engine at substantially atmospheric temperature.

4. The plant in claim 1 wherein said means for maintaining said upper temperature end of said closed cycle heat engine at not significantly below atmospheric temperature includes means for supplying waste heat available at said plant at above atmospheric temperature to said upper temperature end of said engine.

5. The plant in claim 1 wherein said closed cycle heat engine is a Stirling engine.

6. The plant in claim 1 wherein said closed cycle heat engine is designed so that its operation transfers heat from its lower temperature end to said liquefied gas at a temperature only slightly above that of the liquefied gas, thereby yielding a maximum of mechanical energy per unit quantity of liquefied gas supplied to said lower temperature end.

7. The plant in claim 1 wherein there is further provided:

means for collecting gas vaporised during operation of said closed cycle heat engine from said liquefied gas utilised to maintain said lower temperature end of said engine at substantially below atmospheric temperature;

a small number of additional auxiliary open cycle heat engines, such number being at least one;

means for passing said collected vaporised gas through each of said open cycle heat engines sequentially;

means for raising the temperature of said collected vaporised gas, thereby raising its pressure, before entering each said open cycle heat engine, thereby driving each said open cycle engine and yielding mechanical energy.

8. The plant in claim 7 wherein said means for raising the temperture of said collected vaporised gas before entering each said open cycle heat engine includes use of an additional auxiliary closed cycle heat engine with upper temperature end and lower temperature end and working fluid independent of said gas, each said auxiliary closed cycle engine being supplied at its upper temperature end with heat at a temperature not below atmospheric, including any waste heat available at said plant and not otherwise used therein, and designed so that its operation transfers heat from its lower temperature end to said gas at a temperature only slightly above the temerature at which said gas enters said open cycle engine.

9. The plant in claim 1 wherein there is further provided an additional prime mover for driving a dynamo for the production of electrical power.

10. A plant for producing electrical power, including:

prime mover means for driving a dynamo for the production of electrical power;

refrigeration means for producing liquid nitrogen and liquid oxygen gases from the atmosphere at temperatures substantially below atmospheric;

storage means for storing said liquid gases;

an additional Stirling heat engine of closed cycle form, employing a working fluid independent of said liquid gases, having an upper temperature end and a lower temperature end;

means for transferring said liquid gases to said lower temperature end of said Stirling engine, thereby maintaining said end at a temperature below -118°

C.;

means for supplying heat to said upper temperature end of said Stirling engine at above atmospheric temperature from any suitable waste heat available at said plant and not otherwise used therein, thereby driving said Stirling engine and yielding mechanical power for driving a dynamo to produce electricity;

means for collecting gas vaporised from said liquefied gases at said lower temperature end during operation of said Stirling engine;

means for heating said collected gas, thereby raising its pressure;

at least one additional auxiliary open cycle heat engine;

means for using said pressurized collected vaporised gas to drive said open cycle engine to yield mechanical energy.