WO2003102395A2

WO2003102395A2 - Power pistons

Info

Publication number: WO2003102395A2
Application number: PCT/US2003/017779
Authority: WO
Inventors: Robert D. Hunt
Original assignee: Hunt Robert D
Priority date: 2002-06-03
Filing date: 2003-06-03
Publication date: 2003-12-11
Also published as: AU2003237417A8; AU2003237417A1; WO2003102395A3

Abstract

Power pistons and power piston systems capable of producing cooling, heating and/or useful power are disclosed, and include power pistons driven by or used in conjunction with vapor cycles, absorption refrigeration cycles, and partial pressure refrigeration cycles.

Description

POWER PISTONS

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation-in-part of United States Patent Application No. 09/873,983 filed on June 4, 2001. This application claims the benefit of U.S. Provisional Application No. 60/384,788 filed on June

3, 2002. The entire disclosures of the aforementioned applications are incorporated herein by reference.

FIELD OF THE INVENTION

[0002] The present invention relates to power pistons and, more particularly, to power pistons driven by working fluids including those used in refrigeration and/or vapor power cycles.

BACKGROUND OF THE INVENTION

[0003] Most presently known engines rely on combustion of fossil fuels and produce harmful emissions, with the exception of engines powered by hydrogen. Conventional engines use crank shafts, bearings, cams, etc. and operate at efficiencies typically less than thirty-five percent. [0004] As recognized by the inventor hereof, what is needed are new forms of engines capable of higher efficiency operation and that can preferably be driven not only by high temperature heat sources, but low temperature heat sources as well, including solar heat, geothermal heat, and thermal energy within our atmosphere. SUMMARY OF THE INVENTION [0005] The inventor hereof has succeeded at designing power pistons and power piston systems capable of producing cooling, heating and/or useful power.

[0006] A power piston apparatus according to one aspect of the present invention includes a first piston positioned within a first cylinder and a second piston positioned within a second cylinder. The second piston is coupled to the first piston. The first cylinder has at least one associated inlet for receiving a first working fluid and at least one associated outlet for discharging the first working fluid. The second cylinder has at least one associated inlet for receiving a second working fluid and at least one associated outlet for discharging the second working fluid. The first piston has a size greater than the second piston such that movement of the first piston within the first cylinder in response to the first working fluid causes movement of the second piston and produces a pressure in the second working fluid that is greater than a pressure of the first working fluid.

[0007] Methods and systems according to additional aspects of the invention include power pistons driven by or used in conjunction with vapor cycles, absorption refrigeration cycles, and partial pressure refrigeration cycles.

[0008] In certain preferred embodiments of the invention, a high efficiency engine is provided using a multi-stage vapor cycle. For example, a low-boiling-point-liquid may be heated through compression of atmospheric air using one or more power pistons to create a heat source. Air compression at normal ambient temperatures may produce a heat source in excess of 200 F. Heat rejection may be created by using a power piston as a compressor to create a variable, internal low temperature reservoir. Thus, a substantial Delta T can be formed from differences in temperatures of compressed air and the internal refrigeration cycle. Pre-cooling for internal heat rejection may be provided by removing heat (as the heat source to drive a power piston - vaporize the working fluid) from hot compressed air in a multi-stage vapor cycle and then isentropic expansion of the compressed pre-cooled air, causing further cooling of the air via the Joules-Thompson effect. [0009] Each stage of the multi-stage vapor cycle may operate at a different pressure and temperature in order to extract a substantial amount of heat from the hot compressed air. In the first state, sufficient heat may be available to vaporize a working fluid at high-pressure so as to create a high pressure vapor cycle. A second stage vapor cycle may vaporize additional working fluid at a lower temperature and pressure and thus form a second lower pressure vapor cycle. A third stage vapor cycle may vaporize working fluid at a very low temperature and thus create a very low pressure vapor capable of performing significant work using a power piston, which can convert a large volume of low pressure vapor into a smaller volume of high pressure vapor. This multi-stage process reduces the heat level of the compressed air significantly, thereby providing significantly greater temperature reduction than may be obtained by a single vapor cycle, and most if not all of the heat within the compressed air can be beneficially used.

[0010] The compressed air having its heat dramatically reduced may be well below the inversion temperature of air and can thus be further cooled by isentropic expansion, as it performs wor driving a turoine to generate useful power (i.e., mechanical power, electrical power, etc.). This expanded cold air, in conjunction with an internal refrigeration cycle, can perform self-heat rejection and create a variable, artificial low temperature reservoir.

[0011] A multi-stage vapor cycle having internal heat rejection may be highly efficient because substantially all of the heat may be beneficially used within the system to perform beneficial work with little or no heat rejected to the environment. Accordingly, the teachings of the present invention may help prevent or reduce global warming.

[0012] Further areas of applicability of the present invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS [0013] The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein: [0014] Fig. 1 is a block diagram of a power piston according to one embodiment of the present invention;

[0015] Fig. 2 is a block diagram of a power piston system incorporating a vapor cycle according to another embodiment of the invention; [0016] Fig. 3 is a block diagram of a power piston system incorporating an absorption refrigeration cycle according to another embodiment of the invention; and

[0017] Fig. 4 is a block diagram of a power piston system incorporating a partial pressure refrigeration cycle according to another embodiment of the present invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS [0018] The following description of exemplary embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.

[0019] A power piston according to one embodiment of the present invention is illustrated in Fig. 1 and indicated generally by reference character 100. As shown in Fig. 1 , the power piston 100 includes a first piston 102 positioned within a first cylinder 104, and a second piston 106 positioned within a second cylinder 108. The first piston 102 is coupled to the second piston 106 by a connecting rod 110. The first cylinder 104 includes inlets 112, 114 and outlets 116, 118 for receiving and discharging a working fluid, respectively. Similarly, the second cylinder 108 includes inlets 120, 122 and outlets 124, 126 for receiving and discharging a working fluid, respectively. Associated with these inlets and outlets are several control valves 128-142, as further described below. As shown in Fig. 1 , the first piston 102 is larger than the second piston 106.

[0020] In operation, the power piston 100 can be driven by a first working fluid to increase the force (pressure) of a second working fluid (or vice versa). The first working fluid initially flows through a supply line 144 and enters the left side of cylinder 104 through open control valve 128 while valve 132 is closed. This allows the working fluid within the cylinder 104 to apply pressure against the piston 102. Control valve 130 remains closed while pressure release valve 134 opens to allow working fluid to exit the right side of cylinder 104 through an exhaust line 146 so that a pressure differential exists across opposite sides of the piston 102.

[0021] As the first (larger) piston 102 moves left to right in Fig. 1 , force is transferred to the second (smaller) piston 106 within cylinder 108 by the connecting rod 110. A second working fluid is allowed to enter the second cylinder 108 through a supply line 148 and passes through open valve 136 as pressure release valve 140 remains closed. Pressure release valve 142 is open and pressure release valve 138 is closed as the second working fluid contained on the right side of the cylinder 108 is compressed as the piston 106 moves from left to right in Fig. 1 , thus reducing the area of the right side of the cylinder 108. As sufficient pressure is created within the cylinder 108, the second working fluid is forced through pressure release valve 142 and through exhaust line 150.

[0022] The process is reversed as the first working fluid flows through a supply line 152 and enters the right side of the first cylinder 104 through open valve 130 while valve 134 is closed. This allows the pressure of the first working fluid to apply pressure against the right side of the first (larger) piston 102 that is forced from left to right in Fig. 1 with substantial force because the area of the piston 102 is substantial. Valve 128 remains closed and pressure release valve 132 opens to allow the first working fluid to exit the left side of piston 102 through an exhaust line 154 so that a pressure differential exists across opposite sides of piston 102, with the high pressure on the right side of piston 102 and the low pressure on its left side.

[0023] As the large piston 102 moves from right to left in Fig. 1 , force is transferred to small piston 106 by connecting rod 110. The second working fluid is allowed to enter through supply line 148 and passes through open valve 138 while pressure release valve 142 remains closed. Pressure release valve 140 is open valve 136 is closed as the second working fluid contained in the smaller cylinder 108 is compressed as piston 106 moves from right to left in Fig. 1 , thus reducing the area on the left side of piston 106 within cylinder 108. When sufficient pressure is created within the left side of cylinder 108, the second working fluid is forced through pressure release valve 140 into exhaust line 150.

[0024] Valves 128-142 may be solenoid valves and are preferably connected to a common electric power supply, as indicated generally by line 156 in Fig. 1.

[0025] As this process continues, the second working fluid is compressed by the work performed by the first working fluid and a transfer of energy occurs from the first working fluid to the second working fluid, which gains substantial force through a series of force increasing processes as described above. The series of compressions of the second working fluid results in a highly compressed, hot second working fluid, as the heat of compression and mechanical heat transfer combine to heat the second working fluid as it is repeatedly compressed. Both useful heat and a high pressure second working fluid are generated by this process. [0026] The power piston 100 shown in Fig. 1 has no rotary moving parts, crank shaft, or bearings and preferably has only one fixed rod that moves back and forth to produce power (unless additional pistons are employed). Power is accomplished by essentially exchanging volume for force. The working fluid used to drive the power piston 100 may be a gaseous working fluid such as that generated via a vapor power cycle, or by the flow of natural gas from a natural gas well, etc. The power piston 100 may also be driven by a liquid, such as water from a hydro dam, hydraulic fluid, wave action, etc. [0027] As is well know, force equals pressure times, area. Thus, if a low pressure is applied to a large area, a substantial force will result. This is how a wind mill works by having low pressure air, typically about five pounds per square inch, applied to a very large blade area to produce substantial torque (force). The same principal applies to a large diameter piston containing a large amount of surface area. If low pressure is applied to the large diameter piston, a substantial force is generated. This force may be transferred to a smaller piston via a rod in one-hundred eighty degree alignment (or otherwise) with the large piston. The large piston moves forward and the rod moves forward transferring the force of the large piston to the smaller piston. The smaller piston therefore may be capable of pumping a working fluid, such as hydraulic fluid, with substantial force - equal to the force exerted by the large piston.

[0028] Because the small piston has a small area compared to the large piston and because the force pumped by the small piston is equal to the force exerted by the large piston, the pressure of the fluid pumped by the small piston is far greater than the original pressure applied against the large piston, but the volume pumped by the small piston is less; thus, volume (the greater amount of low pressure working fluid applied against the larger piston) is exchanged for greater force (pressure of the working fluid pumped by the smaller piston) at smaller volume. As an example: if a forty inch diameter power piston is moved one inch by a working fluid having a pressure of one hundred pounds per square inch, a force of 125,600 pounds (20 radius X 20 radius = 400 X 3.14 = 1256 sq. in. X 100 p.s.i. = 125,600 Lbs. force) is applied to a piston having a diameter of six inches via a fixed rod, a force of 4,454 pounds per square inch (3 radius X 3 radius = 9 x 3.14 = 28.26 sq. in., 125,600 lbs. force divided by 28.26 sq. in. = 4,454 lbs. per sq. in.) may be performed by the six inch piston for one inch of forward motion. A volume of 1 ,256 sq. inches of working fluid at one hundred pounds per square inch was required to move the forty inch diameter piston forward one inch that results in 28.26 sq. inches of working fluid being pumped by the six inch diameter piston at 4,454 pounds per square inch; therefore, a large volume of low pressure working fluid is exchanged for a small amount of high pressure working fluid.

[0029] The power piston 100 shown in Fig. 1 is capable of converting large volumes of low pressure working fluid into a powerful force. In the case where the smaller piston pumps high pressure hydraulic fluid, the high pressure hydraulic fluid can perform many forms of work, such as powering a hydraulic ram for heavy lifting, rock crushing, etc. or the hydraulic fluid may drive a rotary vane motor to provide rotary motion to drive an electrical generator, run industrial machinery, drive the wheels of a vehicle, power a boat or airplane, etc. [0030] The power piston 100 is forced back and forth by allowing the first working fluid to enter on one side of the larger piston as it is allowed to exit on an opposite side of the piston, thus creating high pressure on the side at which the working fluid enters and low pressure on the opposite side. The switching back and forth of the working fluid flow is accomplished by the control valves. Work may be accomplished in both directions, forward and backward, as force is created in both directions by the force exerted by the working fluid. Likewise, the smaller piston can perform work in both directions, which dramatically increases the performance of the power piston 100.

[0031] Although the power piston 100 shown in Fig. 1 is driven by a single work piston, any number of work pistons may be provided and arranged, for example, with the connecting rod extending from one work piston to the others along an axial line or otherwise. Additionally, smaller pistons may be arranged on both sides of the power piston 100.

[0032] The power piston 100 may be used to form a high pressure pump, compressor, or hydraulic pump. It may also be used to form a powerful vacuum for use as a vacuum pump. Further, it may be used in refrigeration or in cryogen production either as a high pressure compressor or to form a vacuum in which air or another working fluid is allowed to expand and cool due to the Joules-Thompson effect. Still other uses and applications will be apparent to those skilled in the art.

[0033] Fig. 2 illustrates a power piston system 200 for producing heating, cooling and/or useful work (power) according to another embodiment of the present invention. More specifically, the system 200 uses combined power piston compression of a working fluid such as air, using the energy of a refrigerant, and subsequent Joules-Thompson cooling of the inter-cooled compressed working fluid, via isentropic expansion of the working fluid. The system 200 further includes a second low pressure vapor phase power cycle, using power pistons, that produces beneficial compression to provide useful refrigeration for self-heat rejection.

[0034] With further reference to Fig. 2, a supply of liquid refrigerant 202 is withdrawn from reservoir 204 by liquid pump 206 and is forced into lines 208 and through throttle 210 to high pressure vaporizer 212 where it is heated and is vaporized into high pressure vapor that flows through lines 216 to power piston 218 that drives work piston 220, which draws in ambient (atmospheric) temperature and pressure air 222, which is a second working fluid, through lines 224. The power pistons 218, 226, 228, 230, 232 and their throttles 234 preferably function as described above with reference to Fig. 1 in order to transfer power to a second working fluid. The high pressure vapor from the high pressure vaporizer 212 also powers power piston 228, which powers compression piston 236 which further compresses the air 222 previously compressed in piston 220 to higher pressure. The high pressure vapor from the high pressure vaporizer 212 also powers power piston 230, which powers compression piston 238 which further compresses the air previously compressed in pistons 220, 236 to higher pressure, forming the heat of compression as well as forming very high pressure compressed air. In this manner, the energy from the vaporized refrigerant 202 is transformed into high pressure hot air. [0035] The spent high pressure vapor flows from pistons 218, 228, 230 through lines 240 and through turbine 242 that drives generator 244 that generates electricity 246 and then the spent high pressure vapor flows to condenser 248 where it is pre-cooled and partially condensed before flowing to reservoir 204 where it is fully condensed into the liquid refrigerant 202 as it is bubbled beneath cold liquid refrigerant 202 within the reservoir 204.

[0036] The high pressure hot air flows through lines 224 to vaporizer 212 to counter-flow refrigerant within the vaporizer 212, and heat is given off from the hot air to the refrigerant in order to vaporize the refrigerant into high pressure vapor. The formerly hot air is partially cooled by this process as much of its heat is removed.

[0037] The partially cooled air flows from high pressure vaporizer 212 to a low pressure vaporizer 250 where it counter-flows additional refrigerant that is vaporized at a lower pressure so that less heat is needed to vaporize the refrigerant than is needed to vaporize the refrigerant in vaporizer 212, which operates at a higher pressure. The low pressure vaporizer 250 utilizes additional heat from the compressed air and forms a supply of low pressure refrigerant vapor. The compressed air is further cooled by the low pressure vaporizer 250. [0038] The now cold compressed air flows from vaporizer 250 through lines 224 and throttle 252 to turbine 254 that drives generator 256 that generates electricity 246. Isenthalpic expansion of the compressed air to near ambient pressure occurs within the work producing turbine 254. This process derives useful work from the compressed air and further cools the air due to the Joules-Thompson effect. [0039] The cold air flows from the turbine 254 through lines 224 to condenser 248 to provide cooling in order to pre-cool or condense spent refrigerant vapor back to the liquid refrigerant phase. After giving off its cold, the spent air is discharged back into the environment at ambient pressure and only slightly cooler than ambient temperature air as the heat within the air is substantially regenerated in condenser 248.

[0040] A supply of liquid refrigerant 202 is withdrawn from reservoir 204 by liquid pump 206 and is forced through lines 208 and through throttle 258 to low pressure vaporizer 250. The refrigerant counter-flows compressed air, which has previously given off heat to vaporizer 212, within the vaporizer 250 and the refrigerant is vaporized into a low pressure vapor (due to the low level of heat available) that flows through lines 260 to power piston 232 that drives work piston 262 and flows through lines 264 to power piston 226 that drives work piston 226. This process provides work from the low pressure refrigerant vapor that is converted to work in pistons 226, 232 to compress vapor phase refrigerant from an evaporator 268 in order to provide cooling.

[0041] The spent low pressure vapor flows from pistons 226, 232 to condenser 248 where it is pre-cooled and partially condensed before flowing to reservoir 204 where it is fully condensed into liquid refrigerant as it is bubbled beneath cold liquid refrigerant 202 within the reservoir 204.

[0042] The evaporator 268 is preferably located within reservoir 204 and provides a variable internal low temperature reservoir to produce cooling to accomplish condensation of the refrigerant. The cooling effect of the evaporator 268 maintains the liquid refrigerant within the reservoir 204 at a very low temperature. Spent refrigerant vapor that returns to the reservoir 204 is bubbled beneath the cold liquid refrigerant 202 and is condensed back to liquid form.

[0043] A supply of liquid refrigerant 202 is also fed from the reservoir 204 to the evaporator 268 and is evaporated by the latent heat of condensation provided by spent refrigerant vapor that returns to the reservoir 204. The refrigerant vapor from the evaporator 268 flows through lines 270 and is compressed by work piston 262 and is further compressed by work piston 266. The compressed refrigerant vapor is cooled in condenser 248 and returns to the liquid state and then returns to the reservoir 204. [0044] Fig. 3 illustrates a power piston system 300 according to another embodiment of the present invention. In the embodiment of Fig. 3, the system 300 employs internal heat rejection via a variable, internal absorption refrigeration cycle. Multi-stage power cycles are used, having both a high pressure power cycle and a low pressure power cycle, with the heat of vaporization provided by hot compressed air.

[0045] With further reference to Fig. 3, a supply of anhydrous liquid refrigerant 302, such as ammonia, is withdrawn from reservoir 304 for an anhydrous refrigerant vapor power cycle by liquid pump 306 and is forced into lines 308 and through throttle 310 to high pressure vaporizer 312 where it is heated and is vaporized into high pressure refrigerant vapor that flows through lines 308 to turbine 314 that drives generator 316 to generate electricity 318. The spent anhydrous refrigerant vapor flows through lines 308 to pre-cool condenser 320 where it is pre-cooled and partially condensed then flows to reservoir 304 where it is fully condensed to the liquid refrigerant as it is bubbled beneath cold liquid refrigerant 302 within the reservoir 304. [0046] An additional supply of liquid anhydrous refrigerant is withdrawn from reservoir 304 by liquid pump 306 and is forced into lines 322 and through throttle 324 to low pressure vaporizer 326 where it is heated and vaporized into low pressure refrigerant vapor that flows through lines 322 to turbine 328 that drives generator 330 to generate electricity 318. The spent refrigerant vapor flows through lines 322 to pre-cool condenser 320 where it is pre-cooled and partially condensed before flowing to reservoir 304 where it is fully condensed into liquid refrigerant as it is bubbled beneath cold liquid refrigerant 302 within the reservoir 304. [0047] A supply of the anhydrous refrigerant vapor is separated from water within separator 332 and flows through lines 334 to power piston 336 that drives work piston 338, which draws in ambient (atmospheric) temperature and pressure air 340, which is an additional working fluid, through lines 342. The power pistons 336, 344, 346 and their throttles 348 preferably function as described above with reference to Fig. 1 so as to transfer power to a second working fluid. The anhydrous refrigerant vapor from separator 332 also powers power piston 344, which powers compression piston 350 which further compresses the air previously compressed in piston 336 to higher pressure. The anhydrous refrigerant vapor from separator 332 also drives power piston 346, which powers compression piston 352 to further compress the air previously compressed in pistons 338, 350 to higher pressure, forming the heat of compression as well as forming very high pressure compressed air. In this manner, energy from the vaporized anhydrous refrigerant is transformed into high pressure hot air. [0048] The spent anhydrous refrigerant vapor flows from pistons

336, 344, 346 through lines 354 to condenser 320 where it is pre-cooled and partially condensed then flows to reservoir 304 where it is fully condensed into liquid refrigerant as it is bubbled beneath cold liquid refrigerant 302 within the reservoir 304.

[0049] The high pressure hot air flows through lines 342 to a vaporizer/distiller 356 to counter-flow therein a mixture of anhydrous refrigerant and water 358. Heat is given off from the hot air to the anhydrous refrigerant and water mixture in order to vaporize - distill the anhydrous refrigerant out of the water 358 - the refrigerant into high pressure anhydrous refrigerant vapor that is driven out of the water 358 by the heat input. The formerly hot air is partially cooled by this process as much of its heat is removed.

[0050] The partially cooled air flows from high pressure vaporizer/distiller 356 to low pressure vaporizer 326 through lines 342 and counter-flows additional anhydrous refrigerant that is vaporized at a lower pressure such that less heat is needed in order to vaporize the refrigerant than is needed to vaporize the refrigerant in vaporizer/distiller 356, which operates at higher pressure. The low pressure vaporizer 326 utilizes additional heat from the compressed air and forms a supply of low pressure refrigerant vapor. The compressed air is further cooled by the low pressure vaporizer 326.

[0051] The now cold compressed air flows from vaporizer 326 through lines 342 and through throttle 360 to turbine 362, which drives generator 364 to produce electricity 318. Isenthalpic expansion of the compressed air to near ambient pressure occurs within the work producing turbine 362. This process derives useful work from the compressed air and further cools the air due to the Joules-Thompson effect.

[0052] The cold air flows from the turbine 362 through lines 342 to condenser 320 to provide cooling in order to pre-cool or condense spent anhydrous refrigerant vapor back to the liquid phase. After giving off its cold, the spent air is discharged back into the environment at ambient pressure and only slightly cooler than ambient temperature air as heat within the air is substantially regenerated in condenser 320. [0053] An evaporator 366 is preferably located within reservoir 304 that provides a variable internal low temperature reservoir to produce cooling to accomplish condensation of the anhydrous refrigerant. The cooling effect of the evaporator 366 maintains the liquid phase anhydrous refrigerant within the reservoir 304 at a very low temperature. Spent refrigerant vapor that returns to the reservoir 304 is bubbled beneath the cold liquid refrigerant 302 and is condensed back into liquid form.

[0054] A supply of liquid anhydrous refrigerant is also fed from the reservoir 304 to the evaporator 366 and is evaporated by the latent heat of condensation provided by spent refrigerant vapor that returns to the reservoir 304. The anhydrous refrigerant vapor flows from the evaporator 366 through lines 368 and through throttle 370 to an absorber 372 where the anhydrous refrigerant vapor is absorbed into a supply of water 358 that is sprayed into the absorber 372. The water 358 is obtained from the separator 332. The water 358 flows through lines 374 and through throttle 376 and is sprayed into the absorber 372. [0055] Pump 378 withdraws the liquid mixture of anhydrous refrigerant and water from the absorber 372 and forces it through lines 380 to pre-heater 382 and then to vaporizer/distiller 356 where the liquid mixture of anhydrous refrigerant and water is heated by the hot compressed air. The anhydrous refrigerant is vaporized into high pressure anhydrous refrigerant vapor within the vaporizer/distiller 356 then flows to the separator 332 where the anhydrous refrigerant vapor is separated from the hot water.

[0056] The hot water 358 flows from the separator 332 to vaporizer 312 through lines 374 and heat is given off from the hot water in order to vaporize counter flowing anhydrous refrigerant within vaporizer 312. The water is cooled by this process so that it may allow absorption of additional anhydrous refrigerant when it is sprayed in the absorber 372.

[0057] Additional heat is obtained from air 384 that is compressed via air compressor 386 into heat exchanger 382 to provide pre-heating of the mixture of liquid anhydrous refrigerant and water. The air 384 that is compressed and has had its heat removed is expanded and is allowed to exhaust to the environment via throttle 388 as cold ambient pressure air 390. This cold air supply may be used, e.g., to drive a turbine, or as a source of cold air, etc. [0058] A power piston system 400 according to another embodiment of the present invention will now be described with reference to Fig. 4. In the system 400 of Fig. 4, internal heat rejection is performed using a variable, internal artificial heat sink formed by an innovative partial pressure refrigeration cycle. A multi-phase temperature and pressure vapor power cycle is also used, as are multiple refrigerants as further described below. The partial pressure refrigeration cycle provides cooling via an evaporator 38 located within a condenser/reservoir 36, as shown in Fig. 4, and provides refrigeration to the condenser/reservoir. This cycle preferably uses two working fluids: a refrigerant 33 and a pressure equalizing gas 4. In this particular embodiment, the refrigerant 33 is butane and the pressure equaling gas 4 is ammonia. It should be understood, however, that numerous other refrigerants and pressure equalizing gases may be advantageously employed without departing from the scope of the present invention.

[0059] The pressure equalizing gas 4 is bubbled beneath liquid phase refrigerant 33 and the refrigerant 33 is evaporated into a vapor mixture within the evaporator 38. The pressure equalizing gas 4 and vapor of the refrigerant 33 are withdrawn from the evaporator 38 through lines 30 via a compressor 5 and are compressed into an evaporator/condenser 7 that causes the refrigerant to return to the liquid phase due to lowering of the refrigerant's temperature by the condenser 7, which evaporates a second refrigerant 32 within the evaporator/condenser 7, as the pressure of the refrigerant is increased by the compressor 5. The pressure equalizing gas is not liquefied by this process as a lower temperature and greater pressure would be required in order to liquefy the pressure equalizing gas. [0060] The liquid refrigerant and pressure equalizing gas are separated within a separator 3. The liquid refrigerant sinks to the bottom of the separator 3 as the pressure equaling gas 4 rises above the liquid refrigerant. The liquid refrigerant flows through a throttle 2 and supply line 39 back into the evaporator 38 beneath liquid refrigerant 33 at the bottom of the evaporator 38. The pressure equalizing gas flows through throttle 40 and through lines 37 and is again bubbled beneath the refrigerant 33 to lower the partial pressure of the refrigerant 33, causing the refrigerant to evaporate to repeat the refrigeration cycle of the partial pressure refrigeration cycle. The partial pressure refrigeration cycle is preferably isolated from the rest of the system such that the refrigerant 33 and the pressure equaling gas 4 do not mix with the second refrigerant 32, which is preferably a different type of refrigerant (e.g., a low-boiling-point-liquid such as 410A).

[0061] A supply of the second liquid refrigerant 32 is withdrawn from reservoir 36 by liquid pump 34 and is forced into lines 35 and through throttle 27 to high pressure vaporizer 26 where it is heated and is vaporized into high pressure vapor that flows through lines 13 to power piston 15 that drives work piston 18, which draws in ambient (atmospheric) temperature and pressure air 17, which is a fourth working fluid, through lines 24. The power pistons 15, 20, 22 and their throttles 16 preferably function as described above with reference to Fig. 1 so as to transfer power to a second working fluid. The high pressure vapor from the high pressure vaporizer 26 also powers power piston 20, which powers compression piston 21 to further compress the air previously compressed in piston 18 to higher pressure. The high pressure vapor from the high pressure vaporizer 26 also powers power piston 22, which powers compression piston 23 to further compress the air previously compressed in pistons 18, 21 to higher pressure, forming the heat of compression as well as forming very high pressure compressed air. In this manner, energy from the vaporized refrigerant 32 is transformed into high pressure hot air. [0062] The spent high pressure vapor flows from pistons 15, 20, 22 through lines 12 to condenser 8 where it is pre-cooled and partially condensed before flowing to reservoir 36 through lines 31 where it is fully condensed into liquid form as it is bubbled beneath cold liquid refrigerant 32 within the reservoir 36.

[0063] The high pressure hot air flows through lines 24 to vaporizer

26 to counter-flow refrigerant within the vaporizer 26, where heat is given off from the hot air to the refrigerant in order to vaporize the refrigerant into high pressure vapor. The formerly hot air is partially cooled by this process as much of its heat is removed.

[0064] The partially cooled air flows from high pressure vaporizer 26 to low pressure vaporizer 25 through lines 24 and counter-flows additional refrigerant that is vaporized at a lower pressure such that less heat is needed to vaporize the refrigerant than is needed to vaporize the refrigerant in vaporizer 26, which operates at higher pressure. The low pressure vaporizer 25 utilizes additional heat from the compressed air and forms a supply of low pressure refrigerant vapor. The compressed air is further cooled by the low pressure vaporizer 25.

[0065] The cold compressed air flows from vaporizer 25 through lines 24 and through throttle 19 to turbine 14, which drives generator 11 to generate electricity 9. Isenthalpic expansion of the compressed air to near ambient pressure occurs within the work producing turbine 14. This process derives useful work from the compressed air and further cools the air due to the Joules-Thompson effect. [0066] The now cold air flows from the turbine 14 through lines 24 to condenser 8 to provide cooling in order to pre-cool or condense spent refrigerant vapor back to the liquid phase. After giving off its cold, the spent air is discharged back into the environment at ambient pressure and only slightly cooler than ambient temperature air as heat within the air is substantially regenerated in condenser 8.

[0067] Liquid refrigerant is also withdrawn from reservoir 36 by liquid pump 34 and is forced through lines 35 and through throttle 6 to vaporizer/condenser 7. The refrigerant counter-flows the vapor phase of the first refrigerant and pressure equalizing gas within the vaporizer/condenser 7 and provides cooling to the first refrigerant and pressure equalizing gas. The liquid refrigerant 32 is vaporized as it accepts heat from the first refrigerant and pressure equalizing gas. The vapor 32 returns to the reservoir/condenser 36 via lines 31 where it is fully condensed to liquid refrigerant as it is bubbled beneath cold liquid refrigerant 32 within the reservoir 36.

[0068] Liquid refrigerant 32 is also withdrawn from reservoir 36 by liquid pump 34 and is forced through lines 35 and through throttle 28 to low pressure vaporizer 25. The refrigerant counter-flows compressed air, which has previously given off heat to vaporizer 26, within the vaporizer 25 and the refrigerant is vaporized into a low pressure vapor (due to the low level of heat available) that flows through lines 10 to turbine 42 that is connected to generator 41 that generates electricity 9. The low pressure vapor flows from turbine 42 through lines 10 to condenser 8 and is partially condensed. The low pressure vapor returns to the reservoir/condenser 36 via lines 30 where it is fully condensed to the liquid phase as it is bubbled beneath cold liquid refrigerant 32 within the reservoir 36.

[0069] Suitable turbines for use with the present invention include

Tesla turbines and jet turbines (i.e., turbines which utilize jet propulsion for rotation, and which may or may not be bladeless). Exemplary jet turbines are disclosed in applicant's U.S. Provisional Application No. 60/397,445 filed July

22, 2002, U.S. Provisional Application No. 60/400,870 filed August 5, 2002,

U.S. Provisional Application No. 60/410,441 filed September 16, 2002, and

U.S. Provisional Application No. [insert no. here] filed December 10, 2002 [and entitled "Drum Jet Turbine with Counter-Rotating Ring Method of

Manufacture"]. The entire disclosures of the aforementioned applications are incorporated herein by reference.

[0070] The description of the invention is merely exemplary in nature and, thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.

Claims

CLAIMS What is claimed is:

1. A power piston apparatus comprising a first piston positioned within a first cylinder and a second piston positioned within a second cylinder, the second piston being coupled to the first piston, the first cylinder having at least one associated inlet for receiving a first working fluid and at least one associated outlet for discharging the first working fluid, the second cylinder having at least one associated inlet for receiving a second working fluid and at least one associated outlet for discharging the second working fluid, the first piston having a size greater than the second piston whereby movement of the first piston within the first cylinder in response to the first working fluid causes movement of the second piston and produces a pressure in the second working fluid that is greater than a pressure of the first working fluid.

2. The power piston apparatus of claim 1 further comprising a connecting rod mechanically coupling the second piston to the first piston.

3. The power piston apparatus of claim 1 wherein the first and second pistons are configured for reciprocating movement within the first and second cylinders, respectively.

4. The power piston apparatus of claim 3 further comprising a first plurality of valves for alternately applying the pressure of the first working fluid to opposite sides of the first piston for generating the reciprocating movement.

5. The power piston apparatus of claim 4 wherein the first plurality of valves includes two inlet valves and two outlet valves.

6. The power piston apparatus of claim 4 wherein the first plurality of valves are electrically controlled solenoid valves.

7. The power piston apparatus of claim 4 further comprising a second plurality of valves for alternately compressing the second working fluid on opposite sides of the second piston via the reciprocating movement of the second piston.

8. The power piston apparatus of claim 7 wherein the second plurality of valves include two inlet valves and two outlet valves.

9. A method comprising: driving a power piston with a first working fluid in vapor form, the power piston compressing a second working fluid in response to the driving to thereby increase a pressure and temperature of the second working fluid; transferring heat from the second working fluid to the first working fluid in liquid form to cool the second working fluid, the first working fluid in liquid form vaporizing in response to the transferred heat to produce the first working fluid in vapor form.

10. The method of claim 9 further comprising expanding the first working fluid in a turbine after the first working fluid exits the power piston to thereby cool the first working fluid and produce power with the turbine.

11. The method of claim 10 further comprising transferring heat from the first working fluid exiting the turbine to the cooled second working fluid.

12. The method of claim 9 wherein driving includes driving a plurality of power piston apparatuses with the first working fluid in vapor form, the plurality of power piston apparatuses successively compressing the second working fluid in response to the driving.

13. The method of claim 9 wherein the first working fluid is a refrigerant.

14. The method of claim 9 wherein the second working fluid is atmospheric air.

15. The method of claim 9 wherein transferring heat includes transferring heat from the second working fluid to the first working fluid in liquid form within a high pressure vaporizer.

16. A system comprising a power piston and a vapor power cycle for driving the power piston with a vaporized refrigerant.

17. A system comprising at least a first power piston, a second power piston, a first vapor cycle for driving the first power piston, and a second vapor cycle for driving the second power piston, the second power piston being configured for producing refrigeration, the first vapor cycle being thermally coupled to the refrigeration produced by the second power piston for condensing a working fluid of the first vapor cycle.

18. The system of claim 17 wherein the working fluid of the first vapor cycle is at a higher pressure than a working fluid of the second vapor cycle.

19. The system of claim 17 further comprising at least one turbine configured for expanding a working fluid to produce mechanical power.

20. The system of claim 19 further comprising a generator coupled to the turbine for converting the mechanical power into electric power.

21. The system of claim 19 wherein the turbine is configured for expanding a working fluid compressed by the first power piston.

22. The system of claim 21 wherein the working fluid compressed by the first power piston is atmospheric air.

23. The system of claim 19 wherein the turbine is configured for expanding the working fluid of the first power cycle.

24. The system of claim 17 wherein the first vapor cycle comprises the working fluid of the first vapor cycle, a vaporizer, and a working fluid reservoir, and the second vapor cycle comprises the second power piston and an evaporator.

25. The system of claim 24 wherein the evaporator is positioned within the working fluid reservoir for transferring heat from working fluid in the reservoir to working fluid evaporated in the evaporator.

26. A system comprising a power piston and an absorption refrigeration cycle for driving the power piston with an anhydrous working fluid in vapor form.

27. The system of claim 26 wherein the absorption refrigeration cycle comprises an absorber for introducing the anhydrous working fluid into water, a vaporizer/distiller for heating a mixture of the anhydrous working fluid and water, and a separator for separating anhydrous working fluid in vapor form from the water.

28. The system of claim 26 further comprising a turbine and a first vapor cycle for driving the turbine with a working fluid in vapor form to produce mechanical power.

29. The system of claim 28 further comprising a generator coupled to the turbine for converting the mechanical power into electric power.

30. The system of claim 28 further comprising a second vapor cycle for driving a turbine to produce mechanical power, the first vapor cycle operating at a higher pressure than the second vapor cycle.

31. The system of claim 26 wherein the power piston is configured to compress a working fluid to increase a temperature and pressure of the working fluid, and wherein the system is configured for transferring heat tram the compressed working fluid to the absorption refrigeration cycle.

32. A system comprising a power piston, at least a first vapor cycle for driving the power piston with a refrigerant in vapor form, and a partial pressure refrigeration cycle for providing cooling to condense said refrigerant into liquid form.

33. The system of claim 32 wherein the partial pressure refrigeration cycle comprises an evaporator positioned within a working fluid reservoir for transferring heat from working fluid in the reservoir to working fluid evaporated in the evaporator.