EP1075630A1

EP1075630A1 - Systems and methods for converting thermal energy

Info

Publication number: EP1075630A1
Application number: EP97946553A
Authority: EP
Inventors: Jeffrey Stephen Sterling
Original assignee: Individual
Current assignee: Individual
Priority date: 1997-11-10
Filing date: 1997-11-10
Publication date: 2001-02-14
Also published as: AU5170498A; WO1999024766A1; EP1075630A4

Abstract

The present invention provides devices and methods for obtaining mechanical, electrical and cooling power from a high temperature heat source (80), which maybe intermittent, and an ambient temperature heat source (130). In one embodiment of the invention, the working fluid (100) passes through a fluid circuit including a first vaporizer (10), an expansion device (30) for providing useful mechanical power from the vaporized liquid, a first heat exchanger (40) for cooling the high pressure vaporized liquid, a reservoir for collecting (50), by gravity, the high pressure vaporized liquid, a first valve (60) leading to a second heat exchanger (260), which may or may not be necessary, leading by gravity flow to a second valve (70), allowing the cool, low pressure liquid to drain back by gravity to the first vaporizer. In this embodiment, the first vaporizer is heated by a high temperature heat source, and the expansion device provides mechanical power to an electric generator.

Description

SYSTEMS AND METHODS FOR CONVERTING THERMAL ENERGY

Field of the Invention

The present invention is in the field of heating and cooling systems, more particularly in the field of solar-powered heating and cooling systems.

Background of the Invention

Solar energy is a prime source of thermal energy. The total energy radiated to the earth by the sun is 180,000 trillion watts. Lawrence Rocks, et al, The Energy Crisis (Crown Publishers, Inc. New York 1972). However, on a scale comparable to the use of fossil fuels for the provision of thermal energy, the use of solar energy to produce mechanical power is almost non-existent. Unfortunately, this prodigious total power output to the earth is dispersed over a very broad area, so that the power density is very low. While solar cells have been used on an experimental scale to turn sunlight into electricity, the cost of power from solar cells is completely uneconomical. In addition, the power must still be stored for use at night.

The total oil heritage of the United States is about 200 billion barrels. Of this total, over fifty percent has been recovered and burned. The discovery ratio of natural gas to oil is a nearly constant 6,000 cubic feet per barrel of oil. As with oil, the United States faces a dangerous loss of energy self-sufficiency, since the majority of the world's oil is contained in the politically unstable Middle East. Furthermore, both oil and gas are finite resources, which may last only a few more decades at present consumption rates.

Coal is the giant of the fossil fuels, accounting for ninety-six percent of all available energy from the fossil sources. However, until relatively recently, most coal was obtained from mines dug deep into the earth. Deep coal mining is dangerous to life, hazardous to health, and expensive. Many coal miners suffer from the debilitating "black lung" disease. Deep coal mining has given way to the faster and cheaper method of strip mining. However, strip mining is often disastrous environmentally, as it is prohibitively expensive for a mining company to replace the overburden. Without the overburden, erosion of the land is very rapid, and water supplies are polluted by earth and mineral laden runoff. Furthermore, burning coal produces noxious pollutants such as S02, which are hazardous both to the environment and human health.

Atomic energy, once thought to be a viable energy solution in the United States and around the world, is now falling into disfavor as a long-term energy solution. The disasters at Chernobyl and Three-Mile Island notwithstanding, there is still no commercially viable way to dispose of nuclear wastes. For example, the U.S. Department of Energy currently has 1.8 tons of technetium, a radioactive by-product of nuclear fission. The by-product has a half-life of over two hundred thousand years. During all this time, the waste must be stored safe from accident, leaching into ground water, and terrorism. The expense is daunting even projected to the next twenty years, let alone the next twenty thousand.

Therefore, there is a need for a clean, constantly renewable source of power. If the sun could be harnessed, our heating systems could last as long as the sun, and not the tiny amount of time we have left with our dwindling stores of fossil fuels.

Summary of the Invention

The present invention provides systems and methods for obtaining mechanical, electrical and cooling power from a high temperature heat source, which may be intermittent, and an ambient temperature heat source. In one embodiment of the invention, a working fluid passes through a fluid circuit including a first vaporizer, an vaporized liquid, a heat exchanger for cooling the vaporized liquid, a reservoir for collecting, by gravity, the vaporized liquid, a first valve leading to a second heat exchanger for further cooling the liquid, leading by gravity flow to a second valve, allowing the cool, low pressure liquid to drain back by gravity to the first vaporizer. In this embodiment, the first vaporizer is heated by a high temperature heat source, and the expansion device provides mechanical power to an electric generator.

In a second embodiment of the invention, the expansion device of the first embodiment is connected mechanically to a refrigeration compressor fluid circuit through which the working fluid flows. The compressor compresses and thereby heats a working fluid, which then flows to an ambient temperature heat exchanger. The ambient temperature heat exchanger cools the compressed liquid, which then flows through a flow restrictor. The flow restrictor allows the working fluid to expand and cool, and the fluid then flows through a heat exchanger thermally connected with a heat sink, thereby cooling the heat sink. The working fluid then flows back to the compressor, completing the circuit. In a separate fluid circuit a second heat exchanger in the heat sink circulates a liquid through a pipe, providing cooling to any apparatus or space in thermal connection with the circuit.

A third embodiment of the invention is a combination of the first and second embodiments, but further includes a third, ambient temperature circuit. In this third circuit, a working fluid in a vaporizer is heated by an ambient temperature heat source. The vaporized liquid passes into an expansion device, producing useful mechanical energy, which may be used to power an electric generator. The vaporized working fluid then flows to a heat exchanger, then to a reservoir, then to a first valve, then to a heat exchanger, then to a second valve, then to the second vaporizer. In this third embodiment of the invention, the heat exchanger, reservoir, first valve, heat exchanger and second valve are all in thermal connection with a low temperature heat sink. This low temperature heat sink can be made cool by the heat exchanger in the heat sink of the second embodiment of the invention.

A fourth embodiment of the invention has a first circuit and component arrangement similar to the third embodiment. In addition, a parallel circuit, as described in the second embodiment, is used to both add heat to the vaporizer and to cool the heat sink. The juxtaposition of the first heat exchanger of the parallel circuit to the vaporizer of the first circuit allows for the liquid of the parallel circuit to cause, or aid in, the vaporization of the liquid of the first circuit.

A fifth embodiment of the invention is a combination of the elements of the first and the third embodiments of the invention. After the working fluid is vaporized in the high temperature vaporizer and passes through an expansion device, it then passes through a three-way valve. If the valve is opened one way, the working fluid passes through a high temperature circuit, meaning it passes through a heat exchanger, a reservoir, a first valve, a second heat exchanger, a second valve and back to the vaporizer. If the three-way valve is opened the other way, the working fluid passes through an ambient temperature circuit. This means the working fluid passes through a heat exchanger, a reservoir, a first valve, a second heat exchanger, and a second valve, all in thermal connection with a heat sink, and then back to the vaporizer. This embodiment can therefore operate with a high temperature heat source, or with an ambient temperature heat source, with a turn of the three-way valve.

A sixth embodiment of the invention has elements similar to the second embodiment of the invention, except that the ambient temperature heat exchanger is located in thermal connection with the first vaporizer. This arrangement helps to vaporize the working fluid. In addition, in this embodiment the chilled pipe is in thermal connection with the heat exchangers of the first embodiment. Therefore the device can work with either a high temperature heat source or an ambient temperature heat source.

In a seventh embodiment of the invention, either the high temperature heat source, the ambient temperature heat source, or both, are in thermal connection with one or more thermal storage tanks. Therefore, it is an object of the present invention to provide systems and methods to convert thermal energy to mechanical energy.

It is a further object of the invention to provide a system of valves and heat exchangers for inclusion into an organic Rankine cycle engine that replaces the mechanical compressor normally used to facilitate a continual cycle.

It is a further object of the invention to provide a system that stores thermal energy as a low temperature heat sink. It is a further object of the invention to provide a system that uses an ambient temperature heat source and a stored refrigerated heat sink to drive a heat engine.

It is a further object of the invention to provide a system that uses an ambient temperature heat source and stored heated fluid to drive a heat engine.

It is a further object of the invention to provide a system that uses thermal energy derived from the sun to cool an enclosed space as a product of the conversion of the sun's thermal energy to a stored thermal heat sink.

Brief Description of the Drawings

Fig. 1 is a schematic of a first embodiment of the invention, showing a high temperature fluid circuit. Fig. 2 is a schematic of a second embodiment of the invention, showing a compressor fluid circuit and its mechanical connection to the expansion device.

Fig. 3 is a schematic of a third embodiment of the invention, showing an ambient temperature fluid circuit. Fig. 4 is a schematic of a fourth embodiment of the invention, showing an ambient temperature fluid circuit in which a heat exchanger assists in the vaporization of the working fluid.

Fig. 5 is a schematic of a fifth embodiment of the invention in which vaporized working fluid, after doing mechanical work in the expansion device, can be shunted to either a high temperature circuit, if a high temperature heat source is available, or an ambient temperature circuit, if only an ambient temperature heat source is available.

Fig. 6 is a schematic of a sixth embodiment of the invention, in which both a high temperature heat source or an ambient temperature heat source can be used.

Fig. 7 is a schematic of an exemplary embodiment of the present invention.

Detailed Description of the Invention The present invention provides systems and methods for obtaining mechanical, electrical and cooling power from a high temperature heat source, which may be intermittent, and an ambient temperature heat source. In one embodiment of the invention, a working fluid passes through a fluid circuit including a first vaporizer, an expansion device for providing useful mechanical power from the vaporized liquid, a heat exchanger for cooling the vaporized liquid, a reservoir for collecting, by gravity, the vaporized liquid, a first valve leading to a second heat exchanger for further cooling the liquid, leading by gravity flow to a second valve, allowing the cool, low pressure liquid to drain back by gravity to the first vaporizer. In this embodiment, the first vaporizer is heated by a high temperature heat source, and the expansion device provides mechanical power to an electric generator.

As used herein, "ambient temperature heat source" means a heat source at an operating temperature at or slightly above that of the air surrounding the vaporizer. "High temperature heat source" means a heat source at an operating temperature well above that of the air surrounding the vaporizer. As used herein, two objects are "in thermal connection" if they can transfer heat to one another. As used herein, two objects are "in mechanical connection" if they can transfer mechanical power to one another, for instance, by levers, gears, or pulleys. As used herein, two objects are "in fluid connection" if the fluid in the interior of one can flow into the interior of the other. For example, the liquid in the compressor circuit is separate from, and not in fluid connection, with another circuit or circuits.

In a second embodiment of the invention, the expansion device of the first embodiment is connected mechanically to a refrigeration compressor fluid circuit through which a working fluid flows. The compressor compresses and thereby heats the working fluid, which then flows to an ambient temperature heat exchanger. The ambient temperature heat exchanger cools the compressed liquid, which then flows through a flow restrictor. The flow restrictor allows the working fluid to expand and cool, and the fluid then flows through a heat exchanger thermally connected with a heat sink, thereby cooling the heat sink. The working fluid then flows back to the compressor, completing the circuit. In a separate fluid circuit, a second heat exchanger in the heat sink circulates a liquid through a pipe, providing cooling to any apparatus or space in thermal connection with the circuit.

A third embodiment of the invention is a combination of the first and second embodiments, but further includes a third, ambient temperature circuit. In this third circuit, a working fluid in a second vaporizer is heated by an ambient temperature heat source. The vaporized liquid passes into an expansion device, producing useful mechanical energy, which may be used, for example, to power an electric generator. The vaporized working fluid then flows to a heat exchanger, then to a reservoir, then to a first valve, then to a heat exchanger, then to a second valve, then to the second vaporizer. In this third embodiment of the invention, the heat exchanger, reservoir, first valve, heat exchanger and second valve are all in thermal connection with a low temperature heat sink. This low temperature heat sink can be made cool by the heat exchanger in the heat sink of the second embodiment of the invention.

A fourth embodiment of the invention has a first circuit and component arrangement similar to the third embodiment. In addition, a parallel circuit, as described in the second embodiment, is used to both add heat to the vaporizer and to cool the heat sink. The juxtaposition of the first heat exchanger of the parallel circuit to the vaporizer of the first circuit allows for the liquid of the parallel circuit to cause, or aid in, the vaporization of the liquid of the first circuit. A fifth embodiment of the invention is a combination of the elements of the first and the third embodiments of the invention. After the working fluid is vaporized in the high temperature vaporizer and passes through an expansion device, it then passes through a three-way valve. If the valve is opened one way, the working fluid passes through a high temperature circuit, meaning it passes through a heat exchanger, a reservoir, a first valve, a second heat exchanger, a second valve and back to the vaporizer. If the three-way valve is opened the other way, the working fluid passes through an ambient temperature circuit. This means the working fluid passes through a heat exchanger, a reservoir, a first valve, a second heat exchanger, and a second valve, all in thermal connection with a heat sink, and then back to the vaporizer. This embodiment can therefore operate with a high temperature heat source, or with an ambient temperature heat source, with a turn of the three-way valve. A sixth embodiment of the invention has elements similar to the second embodiment of the invention, except that the ambient temperature heat exchanger is located in thermal connection with the first vaporizer. In addition, in this embodiment the chilly pipe is in thermal connection with the heat exchangers of the first embodiment. Therefore the device can work with either a high temperature heat source or an ambient temperature heat source. In a seventh embodiment of the invention, either the high temperature heat source, the ambient temperature heat source, or both, are in thermal connection with one or more thermal storage tanks.

An embodiment of the invention is shown in Figure 7. The invention permits a working fluid 100 to be transported in a closed fluid circuit from an area of high pressure to an area of low pressure, and back to the area of high pressure, without the loss of useful pressure from the high pressure area. This is accomplished without the use of a pump, by a surprisingly clever arrangement of valves and piping. This also occurs in a continuous cycle. Placed in serial fluid connection, i.e., by pipe 20, are a vaporizer 10, a first heat exchanger 40, a first valve 60, a second heat exchanger 260, and a second valve 70, leading back to the vaporizer 10. The vaporizer 10 turns the fluid into a vapor at high pressure. The first heat exchanger 40 cools and condenses the vapor back into liquid and some vapor. The first valve 60 is opened, allowing the liquid to flow down by gravity. The first valve 60 is closed. The liquid now flows through a second heat exchanger 260, becoming an ambient pressure, ambient temperature fluid. The second valve 70 is now opened, allowing the fluid to flow back to the vaporizer 10 by gravity. The second valve 70 is now closed, and the cycle starts all over again.

Once the liquid has passed through the expansion device, the liquid is no longer at high temperature and pressure. Liquid flowing through the second heat exchanger becomes ambient temperature. If the liquid was already at ambient temperature, there is no need to incorporate a second heat exchanger. There could be a direct connection, essentially bypassing the second heat exchanger.

In Figure 7, the general flow of vapor and working fluid 100 will be clockwise. Even though vapor initially flows both clockwise and counterclockwise, the second valve 70 is initially closed, stopping counterclockwise flow. Those times when second valve 70 is open, high pressure vapor does flow into the space between the first valve 60 and second valve 70. The progress of the vapor stops at the first valve 60, since it is closed. As soon as the second valve 70 is closed again, the vapor is condensed to liquid by the second heat exchanger 260 between the first valve 60 and second valve 70.

An expansion device may be placed between the vaporizer 10 and the first heat exchanger 40, to do useful work with the vaporized working fluid 100.

The invention can be used as a motorless refrigeration pump, or in a motorless air conditioning and refrigeration cycle, including one which operates on a conventional heat or power source. The invention can also be used as a replacement for the return pump in a Rankine cycle engine. When used as such, it can be used with a steam engine, or for the purification of water by freezing, and for the production of ice by refrigeration. It may also be used for the recovery of cleaning fluid in the dry cleaning chemical process. This system does not require a refrigerant to be absorbed in order to move the working fluid from the low pressure state to the high pressure state, or the use of a carrier fluid other than the working fluid.

Figure 1 illustrates a first embodiment of the invention, the first circuit 160, which is a high temperature fluid circuit. The direction of fluid and vapor flow is given by the arrows. A high temperature heat source 80 is in thermal connection 240 with a vaporizer 10, which contains a working fluid 100. The working fluid can be any liquid which can be vaporized by the heat sources available. These liquids include, but are not limited to, water, ammonia, and various chlorofluorocarbons, hydrochlorofluorocarbons, hydrofluorocarbons, and azeotropic blends. Suitable working fluids may be found, for example, at page 336 of A. D. Althouse, et al, Modern Refrigeration and Air Conditioning (Goodheart- Willcox Co., Inc. Illinois 1996), incorporated herein by reference. These working fluids may also be referred to as "refrigerant fluids." The working fluid 100 is vaporized and passes through the pipe 20 at high pressure and temperature, to an expansion device 30, where the vaporized working fluid does useful mechanical work. The expansion device 30 can take many forms, including, but not limited to, a steam engine, a turbine, a piston, or an ejector for producing a refrigeration effect. In Figure 1, mechanical connection 190 connects the expansion device 30 to an electric generator 90. The vaporized working fluid 100 then travels through pipe 20 to first heat exchanger 40, where it condenses into liquid in reservoir 50. There may be no need for reservoir 50 in some embodiments. The pipe 20 itself can serve as such a reservoir. First valve 60 is then opened, the fluid flows by gravity downward, and first valve 60 is then closed. First valve 60 is located at the outlet of the reservoir 50. The now condensed working fluid 100 flows through a second heat exchanger 260 where it is cooled and is a low pressure, ambient temperature liquid. Second valve 70 is then opened, allowing the working fluid to flow by gravity back to the vaporizer 10. Second valve 70 is then closed. The high temperature source 80 can be, for example, a solar collector or a geothermal heat source. The valves 60 and 70, and thus the fluid flow, may be controlled manually, or be part of a computerized monitoring and actuating system. The valves 60 and 70 are operated so as to not cause substantial drop in the internal pressure of the vaporizer 10.

A second embodiment of the invention is shown in Figure 2. The second embodiment adds a second fluid circuit 170, a refrigeration compressor circuit, to the first fluid circuit 160, shown in Figure 1. A compressor 110 is mechanically connected to expansion device 30 of the first embodiment of the invention, through mechanical connection 190. Working fluid 100 is compressed in the compressor 110, increasing the temperature and pressure of the working fluid. This working fluid 100 need not be the same type of fluid as the working fluid in the first fluid circuit 160. The working fluid 100 flows in the direction of the arrows through the pipe 20 to heat exchanger 270, which is at ambient temperature, where the working fluid 100 cools. The working fluid 100 then flows in the direction of the arrows, through flow restrictor 220, where both the temperature and pressure of the working fluid drop. Working fluid 100 then flows through heat exchanger 280 which is in thermal connection with heat sink 120, cooling the liquid in the heat sink. Working fluid 100 then flows from the heat exchanger 280, in thermal connection with heat sink 120, back to the compressor 110, completing the cycle. The heat exchanger 290, in thermal connection with heat sink 120, is in a separate fluid circuit. Liquid flowing through that heat exchanger 290 is cooled, causing the pipe 250 to become chilled. This chilled pipe 250 can be used to cool a room, a space, or a material surrounding the pipe. Figure 3 shows a third embodiment of the invention. It adds a third fluid circuit 180, an ambient temperature circuit, to the second circuit 170. As in the first embodiment of the invention, working fluid 100 is vaporized in a vaporizer. This time, however, it is vaporizer 210, an ambient temperature vaporizer. The vapor flows through pipe 20 through expansion device 30, which performs useful mechanical work to power electric generator 90 through mechanical connection 190. Working fluid 100 flows from expansion device 30, through pipe 20, through first heat exchanger 40, then reservoir 50, through first valve 60, second heat exchanger 260, second valve 70, and down again to vaporizer 210. However, in this embodiment of the invention, first heat exchanger 40, reservoir 50, first valve 60, second heat exchanger 260, and second valve 70, are all in thermal connection with heat sink 120. Second vaporizer 210 is heated by an ambient temperature source 130, in thermal connection 240 with the second vaporizer.

Cooling the heat sink is heat exchanger 280, shown in fluid connection with compressor 110 and ambient temperature heat exchanger 270, as in Fig. 2. Because the heat sink 120 reduces the temperature of first heat exchanger 40 and second heat exchanger 260, an ambient temperature heat source 130 can power the expansion device of Figure 3. Also shown in Figure 3 is a refrigerant metering device 140, shown between the flow restrictor 220 and heat exchanger 280, in fluid connection with both. The working fluid 100 in first fluid circuit 160, second fluid circuit 170 and third, ambient temperature fluid circuit 180 may be the same type of fluid, or all of the fluids may be of different types. Since the third fluid circuit 180 is at ambient temperature, it may be useful to maintain a partial vacuum within the third fluid circuit, so that the working fluid 100 will vaporize at the lower temperature.

Fig. 4 shows a fourth embodiment of the invention. Once again an ambient temperature heat source 130 vaporizes a working fluid 100 in the vaporizer 210 by means of the thermal connection 240. The working fluid 100 vaporizes and passes through pipe 20 to expansion device 30. There it does useful mechanical work, such as to generate electricity in electric generator 90, through mechanical connection 190. The working fluid 100, in vapor form, again follows the direction of the arrows and passes through first heat exchanger 40, reservoir 50, first valve 60, second heat exchanger 260, second valve 70, all in thermal connection with heat sink 120. Then the low temperature, low pressure condensed working fluid 100 passes by gravity back into vaporizer 210. However, unlike the third embodiment of the invention, shown in Figure 3, now the heat exchanger 270 from the compressor circuit 170 is in thermal connection with the vaporizer 210, assisting it in vaporizing working fluid 100.

A fifth embodiment of the invention is shown in Figure 5. It consists of both a high temperature circuit 160 and an ambient temperature circuit 180. If a high temperature heat source 80 is available, through thermal connection 240 it vaporizes working fluid 100 in the vaporizer 10. The vaporized working fluid 100 travels through pipe 20 and through expansion device 30. There the working fluid 100 performs useful mechanical work on the generator 90 and on the compressor 110 through mechanical connections 190. The vapor then passes up into three-way valve 150. The three-way valve 150, if high temperature heat source 80 is available, will be opened toward high temperature circuit 160. Therefore the vaporized working fluid 100 will pass through first heat exchanger 40, reservoir 50, first valve 60, second heat exchanger 260, second valve 70, then back through pipe 20 back into vaporizer 10. If only an ambient temperature heat source 130 is available, three-way valve 150 is turned so as to open ambient temperature circuit 180. In that case, the path of the vapor and liquid will be through expansion device 30, three-way valve 150, then on to the first heat exchanger 40, reservoir 50, first valve 60, second heat exchanger 260, second valve 70, all in thermal connection with heat sink 120. Then the working fluid 100 will flow back into the vaporizer 10. As before, the heat sink 120 is cooled by refrigerant compressor circuit 170, which includes the compressor 110, ambient temperature heat exchanger 270, flow restrictor 220, and heat exchanger 280. The compressor 110 is mechanically connected to expansion device 30 through mechanical connection 190.

If the sun is not shining, the compressor circuit may not used. The temperature source can be stored ice or stored heated fluid or other stored forms of energy. The amount of ice necessary to to power the system can be calculated and enough ice can be kept or stored to power the system during times of little or no sunshine. For example, at night, the system can be powered by the stored heated fluid or stored ice. When the sunshine or solar energy returns, the compressor circuit can be used again. Use of the compressor circuit can be facilitated by use of a solar sensor that monitors the solar energy available. Using the compressor when the sun is shining is not the most efficient way to use the system. The system can also be powered by storage of heated fluid. Such heated fluids can be a solar pond or tank of heated fluid.

Figure 6 shows a sixth embodiment of the invention. When a high temperature heat source 80 is available, it is connected through thermal connection 240 to vaporizer 10. Working fluid 100 is vaporized and travels through pipe 20 to expansion device 30, where it performs useful mechanical work, such as on generator 90 through mechanical connection 190. The working fluid 100 then travels through pipe 20, again through first heat exchanger 40, reservoir 50, first valve 60, second heat exchanger 260, second valve 70, and back into vaporizer 10. When only an ambient temperature heat source 130 is available, it is connected through thermal connection 240 to vaporizer 10, and the working fluid 100 follows the same course. However, refrigeration compressor 110 is then operated through mechanical connection 190 to expansion device 30. This causes working fluid 100 to flow through refrigerator compressor 110, where it is compressed to higher temperature and pressure. Working fluid 100, in this compressor fluid circuit 170, then flows through pipe 20 to heat exchanger 270, which is in thermal connection with vaporizer 10, assisting in the vaporization of working fluid 100. Working fluid 100 flows from third heat exchanger 270 through pipe 20 and flow restrictor 220. The working fluid 100 continues to flow through heat exchanger 280 and heat sink 120, where it cools the liquid in the heat sink, flowing back into compressor 110 to complete the cycle. A third circuit has fluid 100 in pipe 20 and this fluid flows through the pipe 20 in the heat sink 120 and valve 230, cooling first heat exchanger 40 and second heat exchanger 260. There is no fluid connection to heat exchangers 40 and 260 with the third circuit having valve 230 in it. Therefore, an ambient temperature heat source 130 can be used to produce useful mechanical work in expansion device 30.

Heat sink 120 may be surrounded by thermal insulation, or any other methods known to provide insulation. In a seventh embodiment of the invention either one or both of possible vaporizers are in thermal connection with one or more thermal storage tanks. Those skilled in the art will now see that certain modifications can be made to the invention herein disclosed with respect to the illustrated embodiments, without departing from the spirit of the instant invention. While the invention has been described with respect to the illustrated embodiments, it will be understood that the invention is adapted to numerous rearrangements, modifications, and alterations, and all of the foregoing are intended to be within the scope of the appended claims.

Claims

CLAIMSWhat is claimed is:

1. A system for providing mechanical, electrical, and cooling power, comprising a high-temperature fluid circuit, comprising the following elements in serial fluid communication:

(a) a vaporizer for vaporizing a working fluid at high temperature; (b) an expansion device in which the working fluid performs useful mechanical work;

(c) a first heat exchanger for cooling the working fluid into liquid;

(d) a reservoir for collecting the working fluid; (e) a first valve leading from the reservoir

(f) a second heat exchanger for cooling a backdraft vapor; and

(g) a second valve leading from the heat exchanger to the vaporizer.

2. The device of claim 1, further comprising a compression circuit, said compression circuit comprising the following elements in serial fluid communication:

(a) a refrigeration compressor for compressing a working fluid, mechanically connected to the expansion device;

(b) a third, ambient temperature heat exchanger for cooling the working fluid;

(c) a flow restrictor for further cooling the working fluid; and (d) a fourth heat exchanger leading back to the compressor, said fourth heat exchanger being thermally connected to a heat sink, cooling the heat sink; and

(e) a fifth heat exchanger is also in thermal connection to the heat sink, wherein said fifth heat exchanger is not in fluid communication with the compressor circuit, and the fifth heat exchanger is in fluid or thermal connection with an apparatus or space to provide cooling thereto.

3. The device of claim 2, further comprising an ambient temperature fluid circuit, comprising, in serial fluid communication:

(a) a second, ambient temperature vaporizer for vaporizing a working fluid at ambient temperature; (b) an expansion device in which the vapor performs useful mechanical work;

(c) a first heat exchanger for cooling the vaporized working fluid back into liquid;

(d) a reservoir for collecting the working fluid; (e) a first valve leading from the reservoir;

(f) a second heat exchanger for cooling a backdraft vapor; and

(g) a second valve leading from the heat exchanger to the vaporizer; wherein the first and second heat exchangers and the reservoir are in thermal connection with a heat sink.

4. The device of claim 3, wherein the third, ambient temperature heat exchanger is in thermal connection with the second ambient temperature vaporizer to provide heat to vaporize the working fluid.

5. A device for providing mechanical, electrical, and cooling power comprising the following elements in serial fluid communication:

(a) a vaporizer for vaporizing a working fluid at high temperature;

(b) an expansion device in which the vapor performs useful mechanical work; (c) a three-way valve;

(d) a heat exchanger for cooling the vaporized refrigerant into liquid;

(e) a reservoir for collecting the working fluid;

(f) a first valve leading from the reservoir; (g) a heat exchanger for cooling a backdraft vapor; and

(h) a second valve leading from the heat exchanger to the vaporizer; wherein the three-way valve is also in serial fluid communication with;

(a) a heat exchanger for cooling the vaporized working fluid into liquid;

(b) a reservoir for collecting the working fluid;

(c) a first valve leading from the reservoir;

(d) a heat exchanger for further cooling the working fluid; (e) a second valve leading from the heat exchanger to the vaporizer; wherein the heat exchangers and the reservoir are immersed in a heat sink, and further including the following elements in separate serial fluid communication:

(a) a refrigeration compressor for compressing a refrigerant, mechanically connected to the expansion device;

(b) a first heat exchanger for cooling the working fluid;

(c) a flow restrictor for further cooling the working fluid;

(d) a second heat exchanger leading to the compressor; wherein the second heat exchanger is thermally connected to the heat sink, cooling the heat sink.

6. The device of claim 2, wherein the apparatus in thermal connection with the heat sink is the heat exchanger in fluid communication with the expansion device and the heat exchanger in fluid communication with the first valve.

7. A device for permitting the transport of a working fluid in a closed fluid circuit from an area of high pressure to an area of low pressure, and back to the area of high pressure, without the loss of useful pressure from the high pressure area, comprising in serial fluid communication: (a) a vaporizer;

(b) a heat exchanger;

(c) a first valve; (d) a heat exchanger; and

(e) a second valve leading back to the vaporizer.

8. A method of providing mechanical, electrical, and cooling power comprising using the device of claim 3.