Fluidized-bed heat exchanger for conversion of thermal energy to electricity
The present disclosure describes heat exchangers for converting thermal energy stored in solid particles to electricity. Electro-thermal energy storage converts off-peak electricity into heat for thermal energy storage, which may be converted back to electricity, for example during peak-hour power generation. The heat exchanger for converting thermal energy stored in solid particles to electricity enables the conversion of thermal energy into electrical energy for redistribution to the grid. In some embodiments, pressurized fluidized-bed heat exchangers may achieve efficient conversion of thermal energy to electricity by providing direct contact of the solid particles with a gas stream.
1. A heat exchanger configured to transfer thermal energy between a gas stream and a stream of solid particles, the heat exchanger comprising:
a means for contacting the gas stream with the stream of solid particles resulting in a transfer of thermal energy between the gas stream and the stream of solid particles;
an outer shell;
an inner shell; and
a means for directing the solid particles stream to the means for contacting comprising a port which penetrates the inner shell and outer shell; wherein
the heat exchanger is configured to gravitationally pass the stream of solid particles through the means for contacting,
the heat exchanger is configured such that the gas stream flows counter-current to the stream of solid particles, and
the means for directing is positioned before the means for contacting, relative to the direction of flow of the stream of solid particles through the heat exchanger.
2. The heat exchanger of claim 1 ,
wherein:
the means for contacting is positioned within the inner shell.
3. The heat exchanger of claim 2 , further comprising a gas inlet configured to direct the gas stream to the means for contacting.
4. The heat exchanger of claim 3 , further comprising a gas outlet configured to receive the gas stream from the means for contacting.
5. The heat exchanger of claim 4 , wherein:
the gas stream has a temperature, and
the temperature is substantially greater at the gas outlet than at the gas inlet.
6. The heat exchanger of claim 4 , wherein:
the gas stream has a temperature,
the temperature is substantially lower at the gas outlet than at the gas inlet.
7. The heat exchanger of claim 4 , wherein:
the gas inlet comprises a first pipe,
the gas outlet comprises a second pipe,
the second pipe is positioned concentrically within the first pipe creating a first annular space, and
the gas stream is configured to flow through the first annular space.
8. The heat exchanger of claim 7 , wherein:
the inner shell is positioned within the outer shell creating a second annular space, and
the gas stream is configured to flow from the first annular space to the second annular space.
9. The heat exchanger of claim 7 , wherein:
the means for contacting is an empty volume within the inner shell.
10. The heat exchanger of claim 1 , further comprising:
a means for distributing the gas stream through the means for contacting, wherein:
the means for distributing is positioned before the means for contacting, relative to the direction of flow of the gas stream through the heat exchanger.
11. The heat exchanger of claim 10 , wherein:
the means for distributing comprises a plate having an orifice, and
the orifice is connected to a bubble cap.
12. The heat exchanger of claim 10 , wherein:
the means for distributing comprises a plurality of pipes having at least one orifice.
13. The heat exchanger of claim 1 , wherein:
the means for contacting results in a portion of the stream of solid particles entrained within the gas stream.
14. The heat exchanger of claim 13 , further comprising:
a means for separating the stream of solid particles from the gas stream.
15. The heat exchanger of claim 14 , wherein:
the means for separating comprises a nozzle having an inlet, a first outlet, and a second outlet,
the inlet is configured to receive the gas stream and the stream of solid particles,
the first outlet is configured to release the gas stream from the nozzle, and
the second outlet is configured to release the gas stream from the nozzle.
16. The heat exchanger of claim 14 , wherein:
the means for separating comprises a filter.
17. The heat exchanger of claim 14 , wherein the filter is a mesh filter.