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Thermal generation of electricity without a turbine

Technology Number: 

1676

Principal Investigator

Mr.
Michael
Epstein

Department: 

Solar Research Facility
Summary 

A novel renewable energy method for storage of concentrated solar power (CSP) thermal energy directly to electrochemical energy that can be used for for distribution.
A crucial issue for CSP technologies today is providing energy capable of dispatchable generation, that is, sources of electricity whose power load can be changed instantaneously with power demand. Further commercial deployment of CSP on a large scale depends on increase of the annual contribution of solar electricity, better coping with the intermittent nature of this resource and rapid integration with existing electrical distribution infrastructure, i.e. smart grids. 
The technology presented here offers a unique solution to these problems while significantly reducing monetary and environmental costs associated with current CSP systems.
Unlike conventional thermal CSP plants, the novel method does not require the use of a turbine to convert heat to electricity, and the electricity is directly obtained from the electrochemical cell during its discharge cycle. Moreover, this energy storage technique precludes the use of electric power generators (e.g. turbines, wind turbines, photovoltaic panels) which are often used to recharge electrochemical cells by applying electrical power to the cells' electrode terminals. This reduces expenses and eliminates inefficiencies of a traditional solar electrical plant.

Applications


  • As modular stand-alone electrical plant for commercial or private use.
  • Integrate into existing power plants for load sharing.

Advantages


  • Directly transform solar thermal energy into electrical potential energy.
  • Transport of large amounts of water in arid areas is not required.
  • Battery can change loading instantaneously for:
    - Use in smart grid and dispatchable generation
    - Easily Incorporated with other green energy solutions

Technology's Essence


This novel system utilizes a rechargeable thermochemical cycle based on Na-S battery technology. The innovation is the exploitation of concentrated solar radiation for thermo-chemical charging instead of electricity from photovoltaic or wind resources as done today. With this concept, a final efficiency of about 50% from solar to electricity can be achieved, which makes a monumental economic impact on existing CSP technologies. The sodium-sulfur battery discharge cycle usually works at temperatures ranging between 300 and 350oC, at which the sodium, sulfur and the reaction product of sodium polysulfide, Na2Sx (where x=3 to 5), exist in their liquid state. Charging of the battery is achieved at temperatures of 1500-1700 oC, when sodium polysulfide is fully decomposed and the full electrical potential of the battery is restored.[1] Instead of charging the Na-S Battery with an external source of electricity to decompose the sodium polysulfide compound back to its Na and S ingredients, it is proposed that the decomposition process will be achieved thermally via CSP.

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