method and apparatus to convert low temperature thermal energy to electricity

• US 7,748,219 B2
• Filed: 03/23/2006
• Issued: 07/06/2010
• Est. Priority Date: 03/23/2005
• Status: Expired due to Fees

• Current Assignee: PDM Solar, Inc.
• Original Assignee: PDM Solar, Inc.
• Inventors: Baker, David M.
• Primary Examiner(s): Nguyen; Hoang M
• Application Number:
  US11/387,405
• Publication Number:
  US 20060213502A1
• Time in Patent Office: 1,566 Days
• Field of Search: 606/412, 606/418, 606/411.5
• US Class Current: 60/641.2
• CPC Class Codes: F03G 6/02 using a single state working fluid
• CPC Class Codes: F03G 7/04 using pressure differences or thermal differences occurring in nature F03G7/06 takes precedence
• CPC Class Codes: F24S 10/72 the tubular conduits being integrated in a block; the tubular conduits touching each other
• CPC Class Codes: F24S 80/30 Arrangements for connecting the fluid circuits of solar collectors with each other or with other components, e.g. pipe connections; Fluid distributing means, e.g. headers
• CPC Class Codes: F24S 90/00 Solar heat systems not otherwise provided for
• CPC Class Codes: F28D 20/0034 using liquid heat storage material
• CPC Class Codes: Y02E 10/46 Conversion of thermal power into mechanical power, e.g. Rankine, Stirling or solar thermal engines
• CPC Class Codes: Y02E 60/14 Thermal energy storage
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors

Abstract

Methods and systems are disclosed to convert low temperature thermal energy to electricity. An example apparatus disclosed herein includes an electrical generating unit to receive heat energy to produce electricity, a concentrator including a heat engine, a liquid piston operatively coupled to the heat engine, and a heat pump operatively coupled to the liquid piston, the heat engine adapted to collect thermal energy, and the heat pump operatively coupled to the electrical generating unit to provide heat to the electrical generating unit. The example apparatus disclosed herein also includes a heat engine floating piston disposed in the heat engine, a heat pump floating piston disposed in the heat pump, and wherein the heat engine floating piston and the heat pump floating piston oscillate.

Claims

1. An article of manufacture storing machine readable instructions which, when executed, causes a machine to:

a. collect thermal energy;

b. transfer the collected thermal energy to a concentrator, the concentrator comprising a heat engine, a liquid piston, and a heat pump; and

c. invoke a series of oscillating cycles of the heat engine, the liquid piston, and the heat pump;

d. the machine controlling the heat engine through at least one of an isothermal expansion phase, an isentropic expansion phase, a constant volume compression phase, and isothermal compression phase, or an isentropic compression phase;

e. to drive an electrical generating unit operatively connected to the heat pump.

2. An article of manufacture in accordance with claim 1 wherein the machine readable instructions are executed by means of a computing device.

3. An article of manufacture in accordance with claim 2 wherein the computing device comprises at least one of:

a server, a personal computer, a personal digital assistant, or an application specific integrated circuit (ASIC).

4. An article of manufacture in accordance with claim 1 wherein at least one inlet valve and one exhaust valve in connection with the heat engine are opened and closed at proper times to apply and remove force from the heat engine piston in phase with the oscillating cycle of the heat engine.

5. An article of manufacture in accordance with claim 4 wherein the inlet valve and the exhaust valve are opened and closed at proper times to cause the machine to oscillate near a resonant frequency.

6. An article of manufacture in accordance with claim 1 wherein at least one of;

the isothermal expansion phase, the isentropic expansion phase, the constant volume compression phase, the isothermal compression phase, or the isentropic compression phase operate at or below atmospheric pressure.

7. An article of manufacture in accordance with claim 1 wherein the heat engine further comprises a measurement sensor of determining the position of the heat engine piston.

8. An article of manufacture in accordance with claim 7 wherein the computing device works in concert with the measurement sensor to position of the heat engine piston into a known starting location.

9. An article of manufacture in accordance with claim 1 wherein the machine readable instructions cause the machine to control a heat pump piston through at least one of an isentropic compression phase, an isothermal compression phase, an isentropic expansion phase, or an isothermal expansion phase.

10. An article of manufacture in accordance with claim 9 wherein the machine readable instructions cause the machine to drive the electrical generating unit with a heat pump fluid during at least one of the isothermal compression phase or the isothermal expansion phase.

11. An article of manufacture in accordance with claim 10 wherein the electrical generating unit is a steam turbine.

12. An article of manufacture in accordance with claim 9 wherein at least one of;

the isentropic compression phase, the isothermal compression phase, the isentropic expansion phase, or the isothermal expansion phase operate at or below atmospheric pressure.

13. An article of manufacture as defined in claim 1 wherein the machine readable instructions cause the machine to control a heat engine piston during the oscillating cycle of the heat engine, the heat engine piston ascending and descending, the oscillating cycle of the heat pump further comprising a heat pump piston to at least one of descend in response to the heat engine piston ascension and ascend in response to the heat engine piston descension.

14. A process for generating electricity from thermal energy comprising:

a. providing a concentrator, said concentrator comprising;

a heat engine, a liquid piston, and a heat pump and having means for executing machine readable instructions;

b. acquiring thermal energy;

c. applying the thermal energy to the heat engine invoking a series of oscillating cycles of the heat engine;

d. wherein the oscillating cycles of the heat engine further comprise at least one of the steps of;

an isothermal expansion, an isentropic expansion, a constant volume condensation, an isothermal compression, or an isentropic compression;

e. transferring said thermal energy from the heat engine to the heat pump by means of a liquid piston, thereby forming concentrated thermal energy,

f. driving an electrical generating unit which is operatively connected to the heat pump by transferring the concentrated thermal energy from the heat pump to the electrical generating unit.

15. A process in accordance with claim 14 wherein said thermal energy comprises low grade thermal energy from at least one of:

solar collectors, geothermal heat sources, or industrial waste heat sources.

16. A process in accordance with claim 15 wherein the process includes an additional step for storing thermal energy between the steps of collecting the thermal energy and transferring the thermal energy to the concentrator.

17. A process in accordance with claim 15 wherein forming the concentrated thermal energy comprises invoking a series of oscillating cycles of the heat engine, the liquid piston, and the heat pump by means of the application of the low grade thermal energy.

18. A process in accordance with claim 14 wherein the oscillating cycles of the heat pump further comprise at least one of the steps of:

an isentropic compression, an isothermal compression, an isentropic expansion, or an isothermal expansion.

19. A process in accordance with claim 18 wherein the operative connection between the heat pump and the electrical generating unit further comprises a heat pump pressure valve and a heat pump vacuum valve, and adding steps for opening and closing the heat pump pressure valve and the heat pump vacuum valve such as to drive the electrical generating unit during at least one of the isothermal compression phase or the isothermal expansion phase.

20. A process in accordance with claim 19 wherein the concentrated thermal energy is in the form of steam.

21. A process in accordance with claim 20 wherein the electrical generating unit is a steam turbine.

22. An article of manufacture having a computing device for storing machine readable instructions and executing those instructions that, when executed, causes a machine to:

a. collect and store low grade thermal energy,

b. transfer the low grade thermal energy to an input of a heat engine through at least one inlet valve,

c. said heat engine comprising a heat engine chamber, a heat engine piston, and being in communication with at least one exhaust valve;

d. the instructions causing the coordinated operation of at least one inlet valve and one exhaust valve applying the thermal energy to move the heat engine piston in a way that causes the heat engine piston to oscillate;

e. the heat engine piston being connected with a liquid piston, having the oscillation of the heat engine piston transfer energy to the liquid piston;

f. a heat pump comprising a heat pump chamber, a heat pump piston, and being in communication with at least one heat pump pressure valve and one heat pump vacuum valve;

g. said heat pump piston connected with the liquid piston such that the heat pump piston descends in response to the heat engine piston ascension and ascends in response to the heat engine piston descension and in a way that the heat pump piston receives energy from the liquid piston, transforming the low grade thermal energy into concentrated thermal energy; and

h. driving and electrical generating unit which is operatively connect to the heat pump.