# US 2005/0109387 A1 · System and method for thermal to electric conversion

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- Number: US 2005/0109387 A1
- Document ID: US20050109387A1
- Status: Published application
- Kind: A1
- Application number: 10/984,262
- Filed: 2004-11-09
- Published: 2005-05-26
- Earliest claimed: 2003-11-10
- Assignees: Practical Technology, Inc.
- Inventors: Robert Marshall
- Web page: https://patentgrep.com/patent/US20050109387A1

## CPC

- H02S 10/10: including a supplementary source of electric power, e.g. hybrid diesel-PV energy systems (combinations with gas-turbine plants F02C6/00)
- F24S 90/00: Solar heat systems not otherwise provided for
- F28D 20/0056: {using solid heat storage material (F28D20/0052 takes precedence)}
- H02S 10/30: Thermophotovoltaic systems (photovoltaic cells specially adapted for conversion or sensing of infrared [IR] radiation H10F10/00; thermoelectric devices H10N10/00)
- F24S 23/74: with trough-shaped or cylindro-parabolic reflective surfaces
- Y02E 10/40: Solar thermal energy, e.g. solar towers
- Y02E 10/50: Photovoltaic [PV] energy
- Y02E 60/14: Thermal energy storage
- Y02E 70/30: Systems combining energy storage with energy generation of non-fossil origin
- H02S: GENERATION OF ELECTRIC POWER BY CONVERSION OF INFRARED RADIATION, VISIBLE LIGHT OR ULTRAVIOLET LIGHT, e.g. USING PHOTOVOLTAIC [PV] MODULES (obtaining electrical energy from radioactive sources G21H1/12; light sensitive inorganic semiconductor devices H10F; light sensitive organic semiconductor devices H10K30/00; thermoelectric devices H10N10/00; pyroelectric devices H10N15/00)
- F24S: SOLAR HEAT COLLECTORS; SOLAR HEAT SYSTEMS (for producing mechanical power from solar energy F03G6/00)
- F28D: HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT (fluid heaters having heat generating means and heat transferring means F24H; furnaces F27; details of heat-exchange apparatus of general)
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A system and method for lower cost, solar thermal generation includes a thermal input block, and an energy storage block.

## Claims

### Claim 1

A system for converting solar energy to electric energy comprising:
an insolation collector;
an insolation to thermal power conversion;
a thermophotovoltaic conversion of thermal power to electric power;
a maximum power point tracking control loop; and
a low impedance electric output.

### Claim 2 (depends on 1)

The system of claim 1, where insolation is collected with a parabolic trough solar collector.

### Claim 3 (depends on 1)

The system of claim 1, further including thermal energy storage.

### Claim 4 (depends on 1)

The system of claim 1, including a heat pump.

### Claim 5 (depends on 1)

The system of claim 1, where said thermophotovoltaic converter contains a photonic band gap emitter.

### Claim 6 (depends on 5)

The system of claim 5, where said photonic band gap emitter has an inverse opal structure.

### Claim 7 (depends on 5)

The system of claim 5, where said photonic band gap emitter has one material with a complex dielectric constant.

### Claim 8 (depends on 5)

The system of claim 5, where emissions peak in the visible spectra.

### Claim 9 (depends on 5)

The system of claim 5, where one or more filters are interposed between said emitter and said photovoltaic cells.

### Claim 10 (depends on 5)

The system of claim 5, where an adjustable power limiter is interposed between said emitter and said photovoltaic cells.

### Claim 11 (depends on 10)

The system of claim 10, where said adjustable power limiter limits the power incident on said photovoltaic cells to match the maximum power point of said photovoltaic cells given the electric load.

### Claim 12 (depends on 11)

The system of claim 11, where a positive and/or negative transient of incident power is applied to said photovoltaic cells and the slope of the change in efficiency of the electric output power from said photovoltaic cells is measured to determine the proximity of the actual power point to the maximum power point and said adjustable power limiter is adjusted to optimize efficiency.

### Claim 13 (depends on 11)

The system of claim 11, where a positive and/or negative electric load transient is applied to said cells and the slope of the change in efficiency of the electric output power from said photovoltaic cells is measured to determine the proximity of the actual power point to the maximum power point.

### Claim 14 (depends on 11)

The system of claim 11, where a lookup table provides an approximate value of incident power necessary for operation near the maximum power point of said photovoltaic cells.

### Claim 15 (depends on 1)

The system of claim 1, where an ultracapacitor lowers the electrical impedance of said photovoltaic cells.

### Claim 16 (depends on 1)

The system of claim 1, where waste heat is supplied for building climate control.

### Claim 17

A means for dispatchable solar thermal energy generation comprising:
a means for collecting thermal energy;
a means for increasing the temperature of the collected energy;
a means for storing thermal energy; and
a means for utilizing the stored thermal energy.

### Claim 18 (depends on 17)

The system of claim 17, where said thermal energy collection means collects solar energy with a parabolic trough solar collector means.

### Claim 19 (depends on 17)

The system of claim 17, where thermal energy collection means sources energy from waste process heat.

### Claim 20 (depends on 17)

The system of claim 17, where said temperature increase means includes a self powered heat pump.

### Claim 21 (depends on 17)

The system of claim 17, where said thermal energy storage means has capacity for greater than approximately 1 week of average consumption.

### Claim 22 (depends on 17)

The system of claim 17, where said thermal storage media has no environmental restrictions.

### Claim 23 (depends on 17)

The system of claim 17, where said thermal storage media has a vacuum insulation means.

### Claim 24 (depends on 17)

The system of claim 17, where said thermal storage medium has a reflective or refractive insulation means.

### Claim 25 (depends on 17)

The system of claim 17, where said thermal energy utilization means is a turbine, a Sterling engine, or a thermophotovoltaic generator.

### Claim 26 (depends on 17)

The system of claim 17, where said thermal energy utilization means is a heater or absorptive chiller.

### Claim 27 (depends on 17)

The system of claim 17, where one or more blocks are paralleled for redundancy or where multiple busses are utilized for redundancy.

### Claim 28

A method of converting solar energy to electric energy including:
collecting insolation;
converting insolation to thermal energy; and
thermophotovoltaic conversion of thermal energy to electric energy; and
storing some electric energy to compensate for load transients.

### Claim 29 (depends on 28)

The method of claim 28, where insolation is collected with a parabolic dish solar concentrator.

### Claim 30 (depends on 28)

The method of claim 28, where backup thermal energy is collected form a fossil fueled burner.

### Claim 31 (depends on 30)

The method of claim 30, where said burner includes a recuperator.

### Claim 32 (depends on 28)

The method of claim 28, where some thermal energy is stored.

### Claim 33 (depends on 32)

The method of claim 32, where a heat pump raises the temperature of said thermal energy.

### Claim 34 (depends on 28)

The method of claim 28, where said thermophotovoltaic conversion includes a photonic band gap emitter material.

### Claim 35 (depends on 34)

The method of claim 34, where said photonic band gap material has an inverse opal structure.

### Claim 36 (depends on 34)

The method of claim 34, where the power incident on said photovoltaic cells is optimized with a filter.

### Claim 37 (depends on 34)

The method of claim 34, where the quiescent input to output power ratio of said photovoltaic cell is measured, a transient shift in power is applied, the input to output power ratio is measured again, and the input or output power is adjusted to increase the input to output power ratio.

### Claim 38 (depends on 28)

The method of claim 28, where electric energy is stored in an ultracapacitor.

### Claim 39 (depends on 28)

The method of claim 28, incorporating redundancy of one ore more functional blocks.

### Claim 40 (depends on 28)

The method of claim 28, where information from multiple nearby distributed systems is utilized to enhance collector cleaning scheduling and/or collector positioning.