CA2744404A1 - Air power system - Google Patents
Air power system Download PDFInfo
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- CA2744404A1 CA2744404A1 CA2744404A CA2744404A CA2744404A1 CA 2744404 A1 CA2744404 A1 CA 2744404A1 CA 2744404 A CA2744404 A CA 2744404A CA 2744404 A CA2744404 A CA 2744404A CA 2744404 A1 CA2744404 A1 CA 2744404A1
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K25/00—Plants or engines characterised by use of special working fluids, not otherwise provided for; Plants operating in closed cycles and not otherwise provided for
- F01K25/08—Plants or engines characterised by use of special working fluids, not otherwise provided for; Plants operating in closed cycles and not otherwise provided for using special vapours
Abstract
This invention relates to an air power system (APS) that the heat is extracted from air (or ground or fluid) at ambient temperature in an evaporator, and utilizes for the organic Rankine cycle system with the low critical temperature hydrofluorocarbons (HFC) or hydrocarbons (HC) working fluid for converting air, fluid or ground thermal energy to electrical energy. These low critical temperature hydrofluorocarbons (HFC) or hydrocarbons (HC) working fluid are with the typical range of critical temperature in the range of -5 °C to 45 °C, similar with the typical air, fluid or ground temperature near the surface of the earth to generate energy.
Description
AIR POWER SYSTEM
Inventor: Ning Meng (Edmonton, CA), Zhaolute Meng (Edmonton, CA), Zhayate Meng (Edmonton, CA) Assignee: Ning Meng (Edmonton, CA) BACKGROUND OF THE INVENTION
[00011 The present invention relates to the organic Rankine cycle system (ORC) wherein heat is extracted from air, fluid or ground thermal energy at ambient temperature with evaporators, and the low critical temperature hydrofluorocarbons (HFC) or hydrocarbons (HC) is used in evaporators as the working fluid of this air power system (APS) to produce electric power economically. In particular, the invention relates to the use of low critical temperature HFC or HC refrigerants as the working fluid for organic Rankine cycle power system powered by air, fluid, or ground thermal energy.
[00021 There is a endless demand for clean renewable energy sources due to the depletion of the earth's supply of fossil fuels and concerns over the contribution to global warming from combustion of fossil fuels.
100031 Air, fluid, or ground thermal energy is freely and 24 hour available.
It is a clean, non-polluting source of energy. Additionally there is an enormous amount of air, fluid or ground thermal energy provided by the sun to the surface of the earth that is available without any Page 1 of 32 equipment to collect it. The temperature of air, fluid or ground thermal energy at any particular area is a function of the geographic location, atmospheric conditions and season change.
100041 Heretofore, Power energy generation systems commonly involve burning fossil fuels to increase the temperature of water to its vapor pressure in the form of steam.
Steam pressure can then generate mechanical power, which in turn is converted to electrical energy. The Rankine cycle has been applied to convert high temperature thermal energy into mechanical or electrical energy in complex plants comprising steam driven turbines typically operating within a temperature range of 400 C to 500 C, under very high pressure. Fossil fuels are used to drive boilers, which produce high temperature, and high pressure steam. Fossil fuel conversion efficiencies of these types of installations may be as high as approximately thirty seven percent (37%). However, the burning of fossil fuels to generate steam can pollute the environment and the fuel is not recoverable.
[00051 Solar energy is clean but relies on the transfer of energy from the sun to the solar devices typically outside a building structure. For example, the photovoltaic ("PV") devices made of specialized silicon materials, able to directly convert sunlight into electricity. Though simple and clean, even after years of development, PV devices remain quite expensive and cost prohibitive, resulting in long pay back periods. Solar thermal electric energy (STE) is another branch of solar energy. STE power is generated using heat from the sun. Solar collectors concentrate the energy of the sun to produce high temperature thermal energy between 400 C and 800 C, and this thermal energy is converted to electricity using conventional or advanced heat engines. There are three kinds of solar thermal electric (STE) technologies: parabolic troughs, power towers, and dish/engine systems. These three kinds of STE technologies need high concentration of solar energy, thus requiring high cost sun concentrating and tracking systems and high levels of solar Page 2 of 32 radiation. The intensity of the solar energy is significantly reduced prior to sunset and after sundown. Therefore, peak energy generation occurs only during daylight hours.
Daylight hours are at a minimum when needed most, during cold winter months.
100061 Geothermal energy relies on deep wells to heat fluids to a boiling point to drive turbines.
The depth of the drill hole can be thousands of feet making the cost prohibitive to individual home owners. Alternative geothermal methods involve extracting the heat from water, which is near the surface of the earth. This method however, requires a supplemental electrical energy source to raise the temperature to room temperature. In addition, pumps and their associated electrical energy costs are required to access the water. Hot springs have been used to heat homes directly or to heat motive chemicals to their boiling point to drive turbines. However, the location and number of these hot springs prohibit wide spread use.
100071 Wind energy relies on a constant supply of wind to drive turbines.
During slack periods, little or no energy is produced.
100081 Nuclear power generates radioactive waste which will have an environmental impact thousands of years from today.
[00091 Hydroelectric power relies on damming up rivers or streams thus having a negative environmental impact on fish migrations, wildlife and the topography of the land.
100101 This invention provides good solutions for cost reduction to produce electricity by using air, fluid or ground thermal energy, without using the expensive solar collecting device. The approaches described herein meet that cost reduction need, which utilize the air, fluid or ground thermal energy for the novel low temperature organic Rankine cycle technology to make electricity.
Page 3 of 32 [0011] For low temperatures heat sources, a wide diversity of technologies has been developed over recent years, which allow us to convert low temperature heat energy into mechanical or electrical energy. A process known as organic Rankine cycle (ORC) with low boiling point organic working fluid stands out. Various organic Rankine cycles for different applications between 100 C and 352 C have been developed on the basis of the ORC with different working fluids.
[00121 The organic Rankine cycle (ORC) is a promising system for conversion of low and medium temperature heat to electricity. The ORC power system works like a Rankine steam power plant, but uses a low boiling point organic instead of water as the working fluid. A certain challenge for air power system is the choice of the organic working fluid properly and of the particular design of the cycle. The ORC systems still need to improve when using low temperature heat source. Moreover, the working fluid also has to fulfill the safety criteria, be environmental friendly, and inexpensive for a power plant.
[00131 The Organic Rankine cycle (ORC) is a vapor power cycle with an organic fluid as the working fluid. Functionally, it resembles the steam cycle power plant: a pump increases the pressure of condensed liquid working fluid, this liquid is vaporized in an evaporator/boiler by extracting heat, the high pressure working fluid vapor expands in a turbine, producing power, and the low pressure vapor leaving the turbine is condensed in a condenser before being sent back to the pump to the next cycle.
[0014) Although, the efficiency of the ORC system depends on the temperature difference between the temperature of condensation (temperature of the surrounding) and the reachable temperature of vaporization. But the types of working fluids also have a big impact on the Page 4 of 32 efficiency of an organic Rankine cycle system. Some types of working fluids have been used in organic Rankine cycle turbine in the past, including various refrigerants and hydrocarbons. For traditional ORC system, various refrigerants and hydrocarbons (as their working fluid) have been patented for ORC cycles for different applications between 100 C and 352 C, the efficiency of the ORC cycle can reach nearly 10% at a temperature of 100 C and nearly 20%
over the temperature of 150 C.
100151 Unfortunately, it is still impossible to utilize conventional ORC
system to extract heat energy from the air, fluid or ground thermal energy, because the temperature those heat source is too low. Thus, there is a big challenge to invent the new ORC working fluids and systems for producing electricity from the low temperature of air, fluid or ground thermal energy between -C to 45 C, and with better efficiency.
[00161 U.S. Pat. No. 4,149,385 to Sheinbaum (1979) discloses a method of using deep wells, a priming fluid, a working fluid, a heat exchanger or a power extracting device as an energy source:
however, deep wells and two fluids are required to either extract high temperature heat or to generate energy.
100171 U.S. Pat. No. 6,240,729 to Yoo et al. discloses a method of converting thermal energy to mechanical energy. The Yoo patent relies on a heat source above ambient temperature to heat fluid beyond its boiling point, which increases the vapor pressure within the heated chamber, thereby forcing fluid out of the chamber and into the flow circuit. The increased weight of the downstream chamber creates a torque about the axle, rotating the frame in an upstream direction.
This method however relies on energy transfer of the heat source fluid to raise the temperature of the motive fluids to their boiling points. The heat source fluid needs to be brought in contact with Page 5 of 32 the motive fluid and heat transfer needs to occur. Because of the need for this heat transfer step, energy is lost. Finally, the invention provides only a unidirectional flow of the gas and therefore energy generation is not maximized.
100181 U.S. Pat. No. 7,089,740 to Ou discloses a method of boiling a liquid in a pressure vessel to generate a high pressure vapor that drives a motor. Heat energy is gathered from a remote high temperature heat source (such as solar or geothermal sources) and heats the vapor in the pressure vessel to a sufficiently high temperature to generate the high pressure vapor.
[00191 For low temperature air thermal energy power system, only U.S. Pat. No.
to Matthew P. Collis discloses a system for generating energy which utilizes motive chemical with boiling point temperature in the range of -5 C to 45 C. However, this patent did not choose the more efficient working fluid for the air thermal energy applications. Their working fluids are very flawed for the system, as the boiling point temperatures of their working fluids are still too high.
[00201 Accordingly, besides the objects and advantages of the energy generating device described in my above patent, several objects and advantages of the present invention are: (1) to provide a method and mechanisms for continuous, 24 hour/day energy generation.
Inventor: Ning Meng (Edmonton, CA), Zhaolute Meng (Edmonton, CA), Zhayate Meng (Edmonton, CA) Assignee: Ning Meng (Edmonton, CA) BACKGROUND OF THE INVENTION
[00011 The present invention relates to the organic Rankine cycle system (ORC) wherein heat is extracted from air, fluid or ground thermal energy at ambient temperature with evaporators, and the low critical temperature hydrofluorocarbons (HFC) or hydrocarbons (HC) is used in evaporators as the working fluid of this air power system (APS) to produce electric power economically. In particular, the invention relates to the use of low critical temperature HFC or HC refrigerants as the working fluid for organic Rankine cycle power system powered by air, fluid, or ground thermal energy.
[00021 There is a endless demand for clean renewable energy sources due to the depletion of the earth's supply of fossil fuels and concerns over the contribution to global warming from combustion of fossil fuels.
100031 Air, fluid, or ground thermal energy is freely and 24 hour available.
It is a clean, non-polluting source of energy. Additionally there is an enormous amount of air, fluid or ground thermal energy provided by the sun to the surface of the earth that is available without any Page 1 of 32 equipment to collect it. The temperature of air, fluid or ground thermal energy at any particular area is a function of the geographic location, atmospheric conditions and season change.
100041 Heretofore, Power energy generation systems commonly involve burning fossil fuels to increase the temperature of water to its vapor pressure in the form of steam.
Steam pressure can then generate mechanical power, which in turn is converted to electrical energy. The Rankine cycle has been applied to convert high temperature thermal energy into mechanical or electrical energy in complex plants comprising steam driven turbines typically operating within a temperature range of 400 C to 500 C, under very high pressure. Fossil fuels are used to drive boilers, which produce high temperature, and high pressure steam. Fossil fuel conversion efficiencies of these types of installations may be as high as approximately thirty seven percent (37%). However, the burning of fossil fuels to generate steam can pollute the environment and the fuel is not recoverable.
[00051 Solar energy is clean but relies on the transfer of energy from the sun to the solar devices typically outside a building structure. For example, the photovoltaic ("PV") devices made of specialized silicon materials, able to directly convert sunlight into electricity. Though simple and clean, even after years of development, PV devices remain quite expensive and cost prohibitive, resulting in long pay back periods. Solar thermal electric energy (STE) is another branch of solar energy. STE power is generated using heat from the sun. Solar collectors concentrate the energy of the sun to produce high temperature thermal energy between 400 C and 800 C, and this thermal energy is converted to electricity using conventional or advanced heat engines. There are three kinds of solar thermal electric (STE) technologies: parabolic troughs, power towers, and dish/engine systems. These three kinds of STE technologies need high concentration of solar energy, thus requiring high cost sun concentrating and tracking systems and high levels of solar Page 2 of 32 radiation. The intensity of the solar energy is significantly reduced prior to sunset and after sundown. Therefore, peak energy generation occurs only during daylight hours.
Daylight hours are at a minimum when needed most, during cold winter months.
100061 Geothermal energy relies on deep wells to heat fluids to a boiling point to drive turbines.
The depth of the drill hole can be thousands of feet making the cost prohibitive to individual home owners. Alternative geothermal methods involve extracting the heat from water, which is near the surface of the earth. This method however, requires a supplemental electrical energy source to raise the temperature to room temperature. In addition, pumps and their associated electrical energy costs are required to access the water. Hot springs have been used to heat homes directly or to heat motive chemicals to their boiling point to drive turbines. However, the location and number of these hot springs prohibit wide spread use.
100071 Wind energy relies on a constant supply of wind to drive turbines.
During slack periods, little or no energy is produced.
100081 Nuclear power generates radioactive waste which will have an environmental impact thousands of years from today.
[00091 Hydroelectric power relies on damming up rivers or streams thus having a negative environmental impact on fish migrations, wildlife and the topography of the land.
100101 This invention provides good solutions for cost reduction to produce electricity by using air, fluid or ground thermal energy, without using the expensive solar collecting device. The approaches described herein meet that cost reduction need, which utilize the air, fluid or ground thermal energy for the novel low temperature organic Rankine cycle technology to make electricity.
Page 3 of 32 [0011] For low temperatures heat sources, a wide diversity of technologies has been developed over recent years, which allow us to convert low temperature heat energy into mechanical or electrical energy. A process known as organic Rankine cycle (ORC) with low boiling point organic working fluid stands out. Various organic Rankine cycles for different applications between 100 C and 352 C have been developed on the basis of the ORC with different working fluids.
[00121 The organic Rankine cycle (ORC) is a promising system for conversion of low and medium temperature heat to electricity. The ORC power system works like a Rankine steam power plant, but uses a low boiling point organic instead of water as the working fluid. A certain challenge for air power system is the choice of the organic working fluid properly and of the particular design of the cycle. The ORC systems still need to improve when using low temperature heat source. Moreover, the working fluid also has to fulfill the safety criteria, be environmental friendly, and inexpensive for a power plant.
[00131 The Organic Rankine cycle (ORC) is a vapor power cycle with an organic fluid as the working fluid. Functionally, it resembles the steam cycle power plant: a pump increases the pressure of condensed liquid working fluid, this liquid is vaporized in an evaporator/boiler by extracting heat, the high pressure working fluid vapor expands in a turbine, producing power, and the low pressure vapor leaving the turbine is condensed in a condenser before being sent back to the pump to the next cycle.
[0014) Although, the efficiency of the ORC system depends on the temperature difference between the temperature of condensation (temperature of the surrounding) and the reachable temperature of vaporization. But the types of working fluids also have a big impact on the Page 4 of 32 efficiency of an organic Rankine cycle system. Some types of working fluids have been used in organic Rankine cycle turbine in the past, including various refrigerants and hydrocarbons. For traditional ORC system, various refrigerants and hydrocarbons (as their working fluid) have been patented for ORC cycles for different applications between 100 C and 352 C, the efficiency of the ORC cycle can reach nearly 10% at a temperature of 100 C and nearly 20%
over the temperature of 150 C.
100151 Unfortunately, it is still impossible to utilize conventional ORC
system to extract heat energy from the air, fluid or ground thermal energy, because the temperature those heat source is too low. Thus, there is a big challenge to invent the new ORC working fluids and systems for producing electricity from the low temperature of air, fluid or ground thermal energy between -C to 45 C, and with better efficiency.
[00161 U.S. Pat. No. 4,149,385 to Sheinbaum (1979) discloses a method of using deep wells, a priming fluid, a working fluid, a heat exchanger or a power extracting device as an energy source:
however, deep wells and two fluids are required to either extract high temperature heat or to generate energy.
100171 U.S. Pat. No. 6,240,729 to Yoo et al. discloses a method of converting thermal energy to mechanical energy. The Yoo patent relies on a heat source above ambient temperature to heat fluid beyond its boiling point, which increases the vapor pressure within the heated chamber, thereby forcing fluid out of the chamber and into the flow circuit. The increased weight of the downstream chamber creates a torque about the axle, rotating the frame in an upstream direction.
This method however relies on energy transfer of the heat source fluid to raise the temperature of the motive fluids to their boiling points. The heat source fluid needs to be brought in contact with Page 5 of 32 the motive fluid and heat transfer needs to occur. Because of the need for this heat transfer step, energy is lost. Finally, the invention provides only a unidirectional flow of the gas and therefore energy generation is not maximized.
100181 U.S. Pat. No. 7,089,740 to Ou discloses a method of boiling a liquid in a pressure vessel to generate a high pressure vapor that drives a motor. Heat energy is gathered from a remote high temperature heat source (such as solar or geothermal sources) and heats the vapor in the pressure vessel to a sufficiently high temperature to generate the high pressure vapor.
[00191 For low temperature air thermal energy power system, only U.S. Pat. No.
to Matthew P. Collis discloses a system for generating energy which utilizes motive chemical with boiling point temperature in the range of -5 C to 45 C. However, this patent did not choose the more efficient working fluid for the air thermal energy applications. Their working fluids are very flawed for the system, as the boiling point temperatures of their working fluids are still too high.
[00201 Accordingly, besides the objects and advantages of the energy generating device described in my above patent, several objects and advantages of the present invention are: (1) to provide a method and mechanisms for continuous, 24 hour/day energy generation.
(2) to provide a method of energy generation, which is non-polluting and does not deplete valuable natural energy resources. (3) to provide an energy source which is not location prohibitive. (4) to provide an energy source which is not cost prohibitive.
[00211 The approaches described previously about this patent have all the listed advantages, which extract air, fluid or ground thermal energy for a organic Rankine cycle system with a low critical temperature HFC or HC working fluid, to produce electricity with high efficiency.
Page 6 of 32 Providing a reliable, long-term, cost effective, and efficient way of using clean renewable energy to obtain electrical power that has long been an unsolved problem, until the present invention.
This invention makes it possible to solve energy problem.
100221 With the foregoing in mind, it is a primary object of the present invention to overcome or substantially alleviate long term problems of the prior art by which clean renewable energy is converted to electrical energy efficiently and in an inexpensive manner.
[00231 Another object of the present invention is to provide reliable, cost effective systems and methods for conversion of air, fluid or ground thermal energy to electricity or do other work, where the size of any such system can be correlated to a desired capacity.
[00241 Another important object is to provide systems and methods for the conversion of low temperature thermal energy, wherever obtained, to electrical energy or do other work using a novel organic Rankine cycle system by which a generator is driven or another work performing mechanism is driven, in a cost effective way.
[00251 It is a further valuable object to provide the novel working fluids for organic Rankine cycle system and related methodology.
100261 In brief summary, the present invention overcomes or substantially alleviates long term problems of the prior art by which clean renewable energy is cost effectively converted to electrical energy. The present invention also provides the method and device for conversion of low temperature thermal energy, wherever obtained, to electrical energy using a novel organic Rankine cycle system to drive an electrical generator, in a cost effective way. The novel organic Rankine cycle system can do other work as well. The present invention provides reliable, cost Page 7 of 32 effective ways for conversion of clean renewable energy and other thermal energy to electricity, where the size of the system can be correlated to the desired capacity.
[00271 It has been discovered by this invention, that some low critical temperature working fluids have unique low temperature applications as a working fluid in an organic Rankine cycle system. One example of the preferred working fluids are hydrofluorocarbons (HFC) or hydrocarbons (HC), which has a low critical temperature (LCT) within the typical temperature ranges of 10 C to 45 C, and very low boiling point (LBT). The present invention provides hydrofluorocarbons (HFC) or hydrocarbons (HC), which has a low critical temperature (LCT) within the typical temperature ranges of 10 C to 45 C, and low boiling point (about -80 C), as the organic Rankine cycle working fluid for this air power system (APS).
[00281 These objects and features of the present invention will be apparent from the detailed description taken with reference to accompanying drawings.
SUMMARY OF THE INVENTION
[00291 In accordance with the present invention, an air power system (APS) comprises a method for continuous electrical energy generation. The APS utilizes a working fluid contained within an evaporator. Possible working fluids have low critical temperature ranges of -5 C to 45 C. The evaporator is exposed to outdoor temperatures at or in close proximity to the surface of the earth.
The majority of the surface area of the evaporator is in the open air, in a fluid exposed to outdoor temperatures or the ground. The evaporator can also be exposed to additional supplemental heat source. The APS is not location limited and can use the air temperatures at any location on earth to generate electrical energy. As the temperature of the working fluid increases, the vapor pressure also increases. The vapor pressure causes a turbine to move and energy to be generated.
Page 8 of 32 The fluid is transferred to a condensation condenser using the low cooling temperatures of the air, water or ground to condensate the working fluid. The condensed working fluid is pumped back to the evaporator for the next cycle.
BRIEF DESCRIPTION OF THE DRAWINGS
100301 FIG. la is a schematic illustration of the single air power system, comprising the low critical temperature HFC or HC working fluid ORC power system with one evaporator.
100311 FIG. lb is a schematic illustration of the single air power system, comprising the low critical temperature HFC or HC working fluid ORC power system with one air condenser.
[00321 FIG. 2a is a schematic illustration of the multiple air power system, comprising the low critical temperature HFC or HC working fluid ORC power system with multiple evaporators.
100331 FIG. 2b is a schematic illustration of the multiple air power system, comprising the low critical temperature HFC or HC working fluid ORC power system with multiple condensers.
100341 FIG. 3a is a temperature-entropy (T-S) diagram of R41, a working fluid is used in the air power system with 20 C condensing temperature for hot climate.
100351 FIG. 3b is another temperature-entropy (T-S) diagram of R41, a working fluid is used in the low temperature organic Rankine cycle air power system with 0 C
condensing temperature for cold climate.
Page 9 of 32 [00361 FIG. 3c is another temperature-entropy (T-S) diagram of R41, a working fluid is used in the low temperature organic Rankine cycle air power system with -20 C
condensing temperature for extremely cold climate.
100371 FIG. 4 is a temperature-saturated pressure diagram of R41, as a working fluid is used in the low temperature organic Rankine cycle air power system.
100381 FIG. 5 is a temperature-latent heat diagram of R41, as a working fluid is used in the low temperature organic Rankine cycle air power system.
[00391 FIG. 6 is an evaporation temperature-ORC system efficiency diagram of R41, as a working fluid is used in the low temperature organic Rankine cycle air power system, with 20 C
condensing temperature for hot climate.
[00401 FIG. 7 is an evaporation temperature-ORC system efficiency diagram of R41, as a working fluid is used in the low temperature organic Rankine cycle air power system, with 0 C
condensing temperature for cold climate.
100411 FIG. 8 is an evaporation temperature-ORC system efficiency diagram of R41, as a working fluid is used in the low temperature organic Rankine cycle air power system, with -20 C condensing temperature for extremely cold climate.
[00421 FIG. 9a is another temperature-entropy (T-S) diagram of R23; a working fluid is used in the low temperature organic Rankine cycle air power system, with 0 C
condensing temperature for cold climate.
Page 10 of 32 [00431 FIG. 9b is another temperature-entropy (T-S) diagram of R23; a working fluid is used in the low temperature organic Rankine cycle air power system, with -20 C
condensing temperature for extremely cold climate.
100441 FIG. 10 is a temperature-saturated pressure diagram of R23, as a working fluid is used in the low temperature organic Rankine cycle air power system.
100451 FIG. 11 is a temperature-latent heat diagram of R23, as a working fluid is used in the low temperature organic Rankine cycle air power system.
[00461 FIG. 12 is a condensing temperature-ORC system efficiency diagram of R23, as a working fluid is used in the low temperature organic Rankine cycle air power system, with 25 C
evaporation temperature.
100471 FIG. 13 is an evaporation temperature-ORC system efficiency diagram of R23, as a working fluid is used in the low temperature organic Rankine cycle air power system, with 0 C
condensing temperature for cold climate.
[00481 FIG. 14 is an evaporation temperature-ORC system efficiency diagram of R23, as a working fluid is used in the low temperature organic Rankine cycle air power system, with -20 C condensing temperature for extremely cold climate.
DETAILED DESCRIPTION OF THE INVENTION
100491 The present invention utilizes, in some forms, the free and limitless air, fluid or ground thermal energy to produce electricity. The scale of commercial installations of the present invention can be tailored to the need, ranging from small stand alone systems for residential and Page 11 of 32 small business use to intermediate sized plants for industrial plant or factory use to massive assemblies design to supplement the supply of electricity or to mitigate against if not, eliminate an electrical energy crisis, such as the recent one in Japan. The present invention is economical to install and maintain, and is reliable and not maintenance-intensive, and is efficient and cost effective to operate and does not pollute the environment.
[00501 Using the present invention, businesses, industrial plants, retail and office buildings, homes, farms and villages can produce their own electrical power, and avoid having to pay, the ever-escalating price of purchased electrical power generated from fossil and nuclear fuels.
[00511 This invention is capable of making significantly more energy and efficiency than conventional ORC technologies. Prior art, the ORC systems are incapable of converting the air thermal energy to electricity, but the present invention, can be used to convert electrical energy even with the air thermal energy as well.
100521 The present invention is a better choice, which can be scaled or sized to independently produce as much electrical energy as needed on site, such as the energy needed to power a home or business, pump water, irrigate land and run remote communication installations.
100531 Unlike centralized forms of power generations, de-centralized use of on-site air obtained electrical power needs no far-flung distribution network of gigantic towers and high voltage lines, instead, it utilizes a universally available asset, air thermal energy.
[00541 The cost of the generating equipment itself used in the production of power for a building can be amortized over the life of the building, as part of debt financing (mortgage). Amazing, as it may seem, one of the largest and most uncontrollable costs a building owner faces is the ever Page 12 of 32 escalating cost of electrical power. Using the present invention, one actually has the ability to eliminate the cost of purchased electrical power now and for years to come.
100551 When land and water were plentiful and energy was cheap, little was known about the delicate balance existing between the environment and the extraction, burning, and wasting of non-renewable fuels. Now it is all too apparent that our supply of fossil fuels is limited and that these sources are causing damage to our atmosphere, water supplies, and food chain damage that is or may soon become irreversible. The costs, too, for fossil fuels to continue upward as the more accessible fuel deposits are consumed, and as the costs for machinery, labor, and transportation continue to rise around the world.
[00561 Ironically, the best answer to the world's need for energy has always been the clean renewable energy. The clean renewable energy can completely fulfill our energy requirements while helping us to become independent of the negative aspects inherent in conventional electrical power generation. Switching to air-derived electrical power will reduce the pollution produced by coal, oil and nuclear fuels. It will also stop the use of coal and oil and allow us to conserve these resources for later and perhaps valuable uses. Harnessing the APS will also reduce, or eliminate the need for nuclear power and mitigate its many risks and problems, such as the recent one in Japan.
100571 The present invention is not space-intensive. The APS, in some forms, can be installed on an existing yard so that it essentially takes up no additional space at all.
Ground-mounted systems on a pad or superimposed above a roof or parking lot are also options as well. Deck mounting is a further option.
Page 13 of 32 [00581 Various embodiments of the present invention may be used in conjunction with residences, office buildings, manufacturing facilities, apartment buildings, schools, hospitals, remote communications, telemetry facilities, offshore platforms, water pumping stations, desalination systems, disinfection systems, wilderness camping, headquarters installations, remote medical facilities, refrigeration systems farms and dairies, remote villages, weather stations, and air conditioning systems.
100591 The present invention is also useful: in (a) providing catholic protection against galvanite corrosion, (b) storage of electrical energy in batteries, in some circumstances and (c) generation and sale of electricity to utility companies.
100601 The types of working fluids of the ORC system have a big impact on the efficiency of an organic Rankine cycle air power system for the various thermodynamic cycles in which the turbine operates. Some types of working fluids have been used in organic Rankine cycle in the past, including some refrigerants and hydrocarbons. Generally, the selection of the working fluid will consider the range of heat temperature of an evaporator and heat sink temperature of a condenser in a closed loop of the ORC system. In the present invention, different with past, the low critical temperature hydrofluorocarbons (HFC) or hydrocarbons (HC) are selected as the working fluid to be used in the closed loop of the ORC system, with the HFC or HC working fluids critical temperature ranges of 10 - 45 C, close to air, fluid or ground thermal temperature range of -5 C - 45 C.
100611 The selection of the working fluid is a key importance for this air temperature Rankine cycle system. In order to extract low-grade air, fluid or ground thermal energy, the working fluid must have a much lower boiling point. And a fluid with a low latent heat will have more high Page 14 of 32 efficiency, as it ejects less heat energy to the condenser, thus reduces the required heat, as the results, reduces the cost, for reducing the flow rate, the size of the power facility, and the pump consumption. The freezing point of the selected working fluid should be lower than the lowest temperature in the cycle and also have a low environmental impact.
[00621 Conventional organic Rankine cycle (ORC) is a developed process for conversion low and medium temperature heat to electricity from a temperature range of 80 C -352 C, but there are no conventional ORC systems that can convert low temperature heat to electricity from a temperature range of -5 C - 45 C.
[00631 FIG. la and Fig. l b show a schematic of the air power system 10, which generally includes evaporator 20 and the organic Rankine cycle with a temperature range of -5 C - 45 C.
The evaporator 20 generally includes a circulate pump 22; and plenty of circulation pipes 23.
The ORC system 30 generally includes a turbine 31, a turbine generator 38, a condenser 34, and circulation pipes 36 and a circulate pump 22. In addition, generator 38 and turbine 31 are connected on a shaft 35. The working fluid is pumped and circulated in the closed loop 23 and 26 of ORC system. The power generated by generator 38 may be used in various applications, including, but not limited to: powering commercial, residential house and buildings.
100641 This air power system 10 has evaporator 20. Located within the evaporator is a working fluid with low critical temperature hydrofluorocarbons (HFC) or hydrocarbons (HC) with the critical temperature ranges of 10 - 45 C. Some suitable low critical temperature hydrofluorocarbons (HFC) or hydrocarbons (HC) include, but are not necessarily limited to:
[00651 R23, Fluoroform (CHF3) 100661 R32, Methylene fluoride (CH2F2) Page 15 of 32 100671 R41, Methyl fluoride (CH3F) [00681 R116, Perfluoroethane (CF3CF3) [00691 R1150, Ethylene (CH2CH2) [00701 R170, Ethane (CH3CH3) [00711 The properties comparing between the low critical temperature hydrofluorocarbons (HFC) or hydrocarbons (HC) working fluids are showed in table 1. The low critical temperature hydrofluorocarbons (HFC) or hydrocarbons (HC) working fluids ORC system is able to achieve a high efficiency even at a very low temperature between of -5 C - 40 C, due to its low boiling point, low critical temperature, and small latent heat characteristic. At the low temperature ranges -5 C - 40 C, the low critical temperature hydrofluorocarbons (HFC) or hydrocarbons (HC) working fluids have very high saturated pressure, thus can make more mechanical power at this low temperature. Consequently, the efficiency of APS those the low critical temperature hydrofluorocarbons (HFC) or hydrocarbons (HC) working fluids are higher than other conventional working fluids. Present invention addresses the working fluid with lower critical temperature, and higher pressure at the operating temperature area.
Table 1 Comparison of the low critical temperature HFC and HC
Working Chemical Critical Critical Boiling Latent heat 20 C
fluid formula temperature pressure temperature at 20 C Saturate pressure C MPa C KJ/mol MPa R23 CHF3 26.1 4.83 -82.0 5.3 4.16 R41 CH3F 44.1 5.90 -78.3 8.7 3.40 R116 CF3CF3 19.9 3.05 -78.1 0 3.04 R1150 CH2CH2 9.2 5.04 -103.8 - 5.41 R170 CH3CH3 32.2 4.87 -88.6 6.2 3.76 Page 16 of 32 [00721 The low critical temperature hydrofluorocarbons (HFC) or hydrocarbons (HC) working fluids have many advantages. It is inexpensive, non-explosive, most non-flammable. In addition, it has no ozone depleting potential (ODP) and a low global warming potential (GWP). Due to its relatively high working pressure, the low critical temperature hydrofluorocarbons (HFC) or hydrocarbons (HC) working fluid ORC system is more compact than the system operating with other conventional working fluids.
100731 The evaporator 20 is placed in a position so that the evaporator 20 is exposed to the earth's hot side of the air temperatures, ground temperatures or fluid temperatures. The evaporator 20 has an outlet regulator valve. The regulating valve is connected to a gas turbine 31.
The turbine is linked to a drive shaft 35, which is linked to an electric generator 38. The turbine 31 contains an outlet valve, which connects to a condenser 34. The condenser 34 is placed in a position so that the condenser 34 is exposed to the earth's cold side of the air temperature, fluid temperature or ground temperature. The condenser 34 contains an outlet regulator valve. The outlet regulator valve connects to a fluid pump 22. The fluid pump 22 connects to a one way inlet valve on the evaporator 20. The above system will have one or evaporator/condenser linked each other to one or multiple turbine depending on space restrictions and the desired amount of energy to be generated. The above system will have the capacity to replace the working fluid depending on the environmental temperatures encountered by the evaporator 20 or condenser 34.
The turbines 31 can be any kind of expansion machine, either impulse or reaction type.
[00741 The manner of generating electric energy using an air power system (APS) begins with radiant or conductive heat transfer from the air, ground or fluid to the air tight pressure evaporator 20. The surrounding temperature of the evaporator 20 is in the range of -5 C. to 45 C. The working fluid inside the evaporator 20 has a boiling point much below the ambient Page 17 of 32 temperature. The liquid inside the evaporator 20 increases by increasing evaporating temperature, consequently the vapor pressure inside the evaporator 20 also increases.
100751 Preferably, heat transfer from the ambient environment immediately surrounding the evaporator 20 to the working fluid in the evaporator 20 causes the liquid working fluid to boil or vaporize. This heat transfer is generated solely by the difference in temperature between the ambient environment and the temperature of the working fluid within the evaporator 20.
100761 When sufficient pressure has built within the evaporator 20, the gas is released through a regulator valve with sufficient force to turn a gas turbine 31. As the turbine 31 turns it causes a drive shaft 35 to rotate. The drive shaft 35 is linked to a generator 38 while it rotates and electrical energy is generated. After released energy, the gas flows from the gas turbine 31 into a condenser 34. The condenser 34 is surrounded by temperatures in the range of -30 C. to 20 C.
The gas begins to liquated within the condenser 34. When sufficient gas has condensed, the liquid fluid is released through the regulator valve to a pump 22. The liquid working fluid is pumped back into the one way inlet valve on the evaporator 20 and for the cycle repeats.
[00771 In the summer, the evaporator 20 may be exposed to ambient air temperature and the condenser 34 may be exposed to fluid temperature or ground temperature (Fig.1 a). In winter, the evaporator 20 may be exposed to fluid temperature or ground temperature and the condenser 34 may be exposed to either ambient air temperature, cold fluid temperature or cold ground temperature (Fig.1b). The evaporator 20 also may be exposed to ground temperature and the condenser 34 may be exposed to either ambient air temperature, fluid temperature or cold ground temperature.
Page 18 of 32 [00781 In order to provide more energy production, it is beneficial to have multiple evaporators 20 in operation for hot climate. Fig. 2a is a schematic illustration of the air power system with multiple evaporators, comprising the ORC power system with the low critical temperature HFC
or HC working fluid. This air power system 10 can range in size from 10 KW to 1000 MW; and also, multiple air power systems can be used to form a power plant of any size. The power generated by an air power system 10 may be used in various applications, including, but not limited to: powering commercial and residential buildings.
100791 In order to provide more energy production, it is also beneficial to have multiple condensers 34 in operation for cold climate. Fig. 2b is a schematic illustration of the air power system with multiple air cooling condensers with ground or fluid as heat sources, comprising the ORC power system with the low critical temperature HFC or HC working fluid.
This air power system 10 can range in size from 10 KW to 1000 MW; and also multiple air power systems can be used to form a power plant of any size.
[00801 Fig. 3a is a temperature-entropy (T-S) diagram of R41 APS 10 operations with 20 C
condensing temperature for hot climate (as show in Fig. la and Fig. 2a). The R41 working fluid is pumped while increasing the pressure from state point 1 to point 2, and preheating to approximately 40 C from state point 2 to point 3, thus evaporating to approximately 53.8 atm from state point 3 to point 4 in the evaporator 20, and overheated from state point 4 to point 5.
At turbine 31, the high pressure R41 vapor is allowed to expand and release pressure energy to produce power, reducing the temperature of the R41 vapor to approximately 20 C from state point 5 to point 6, to the pressure approximately 34 atm. From state point 6 to point 1, the R41 vapor is condensed for rejecting the latent heat, and then changes its vapor phase back to liquid phase. In this exemplary embodiment, the efficiency of the R41 APS 10 is approximately 11.8%.
Page 19 of 32 This temperature-entropy (T-S) diagram indicated R41 is best suited working fluid for using in the very hot climate.
100811 Fig. 3b is another temperature-entropy (T-S) diagram of R41 APS 10 operations with 0 C condensing temperature (as show in Fig. Ib and Fig. 2b). The R41 working fluid is pumped while increasing the pressure, from state point 1 to point 2, and preheating to approximately 40 C from state point 2 to point 3, thus evaporating to approximately 53.8 atm from state point 3 to point 4 in the evaporator 20, and overheated from state point 4 to point 5. At turbine 31, the high pressure R41 vapor is allowed to expand and release pressure energy to produce power, reducing the temperature of the R41 vapor to approximately 0 C from state point 5 to point 6 to the pressure approximately 20.4 atm. From state point 6 to point 1, the R41 vapor is condensed for rejecting the latent heat, and then changes its vapor phase back to liquid phase. In this exemplary embodiment, the efficiency of the R41 ORC system 30 is approximately as high as 18%. This temperature-entropy (T-S) diagram indicated R41 has a better efficiency for using with lower condensing temperature.
100821 Fig. 3c is another temperature-entropy (T-S) diagram of R41 APS 10 operations with -20 C condensing temperature (as show in Fig. lb and Fig. 2b). The R41 working fluid is pumped from state point 1 to point 2 while increasing the pressure, and preheating to approximately 40 C from state point 2 to point 3, thus evaporating to approximately 53.8 atm from state point 3 to point 4 in the evaporator 20, and overheated from state point 4 to point 5.
At turbine 31, the high pressure R41 vapor is allowed to expand and release pressure energy to produce power, reducing the temperature of the R41 vapor to approximately -20 C from state point 5 to point 6 to the pressure approximately 11.4 atm. From state point 6 to point 1, the R41 vapor is condensed for rejecting the latent heat, and then changes its vapor phase back to liquid Page 20 of 32 phase. In this exemplary embodiment, the efficiency of the R41 APS 10 is approximately as high as 23%. This temperature-entropy (T-S) diagram indicated R41 has a excellent efficiency for using with very low condensing temperature.
[0083] Fig. 4 is a R41 working fluid saturated pressure-temperature diagram.
Comparing the boiling temperature (100 C) of water, R41 working fluid has a very low boiling point (-78.3 C), a low critical temperature (44.1 C) and a very high critical pressure (59.0 atm); consequently that the low critical temperature R41 working fluid APS system 10 can have a very high operating pressure even at a low operating temperature. For the exemplary embodiment, at the evaporating temperature 40 C, the R41 saturated pressure is 53.8 atm, and at the condensing temperature 10 C, the R41 saturated pressure is 20.5 atm, the pressure difference is 33.3 atm between two temperatures, much higher than other conventional ORC systems. For a turbine system, the pressure difference between the evaporating pressure and condenser pressure is very important to rotate the turbine for mechanical work. This is another reason why low critical temperature HFC or HC working fluid is selected for this air power system 10.
[0084] Fig. 5 is a plot of the R41 working fluid latent heat-temperature diagram, illustrating thermal characteristic of the R41 working fluid APS system 10. As showed in Fig 5, the R41 working fluid has very low latent heat, which is suited to get high efficiency of the low temperature applications. For example, at the condense temperature of 20 C, the R41 latent heat is only 8.8 KJ/mol, much less than water latent heat (40.68 KJ/mol) of water;
consequently the R41 APS system 10 will have a higher efficiency.
[0085] Fig. 6 is a plot of efficiency of the R41 working fluid air power system 10 versus evaporation temperature, with the same condenses temperature 20 C (as show in Fig. 2a and Page 21 of 32 Fig. 2a). The cycle efficiency of the R41 APS 10 shows depending on the temperature of evaporation. At the temperature 30 C, the efficiency of this APS 10 is 6.2 %, and increases to 11.8 % at the evaporation temperature 40 C. This shows that in the summer, a hotter climate (for example in Africa) enable the APS to achieve a higher efficiency.
100861 Fig. 7 is a plot of efficiency of the R41 working fluid air power system 10 versus evaporation temperature, with the same condenses temperature 0 C (as show in Fig. lb and Fig.
2b) The cycle efficiency of the R41 APS 10 will improve by decreaseing the cooling temperature of condenser. This shows that the hot summer is able to achieve a higher efficiency of this APS, if it is possible to get enough cooling sources. For example, the water temperature is close to 0 C in deep ocean even in summer.
[00871 Fig. 8 is an evaporation temperature-ORC system efficiency diagram of R41, as a working fluid is used in the low temperature organic Rankine cycle air power system, with -20 C condensing temperature for extremely cold climate with air as cooling sources (as show in Fig.lb and Fig.2b). At the heating temperature 10 C, the efficiency of this APS 10 is 12.5 %.
This shows that a colder climate enable the APS to achieve a more efficiency with the heat sources from the ground or fluid (about 15 C).
[00881 Fig. 9a is another temperature-entropy (T-S) diagram of R23; another working fluid is used in the low temperature organic Rankine cycle air power system, with 0 C
condensing temperature for APS 10 (as show in Fig.lb and Fig.2b). The R23 working fluid is pumped from state point 1 to point 2 while increasing to the desired pressure, and preheating to 25 C from state point 2 to point 3, thus evaporating with approximately 46.9 atm from state point 3 to point 4, and overheated from state point 4 to point 5. At turbine 31, the high pressure the R23 gas is Page 22 of 32 allowed to expand and release energy to produce power, reducing the temperature of the R23 gas to approximately 0 C from state point 5 to point 6 to the pressure 24.9 atm.
The R23 vapor is condensed for rejecting the latent heat from state point 6 to point 1, and then changes its vapor phase back to a liquid phase. In this exemplary embodiment, the efficiency of the R23 working fluid APS 10 is approximately 13.5 %. This temperature-entropy (T-S) diagram of this exemplary system indicated that the lower critical temperature hydrofluorocarbons (HFC) or hydrocarbons (HC) working fluid is best suited for use in hotter climates to get a higher efficiency with more cooling resources.
100891 Fig. 9b is another temperature-entropy (T-S) diagram of R23; a working fluid is used in the low temperature organic Rankine cycle air power system, with -20 C
condensing temperature for extremely cold climate (as show in Fig. lb and Fig.2b). The R23 working fluid is pumped from state point 1 to point 2 while increasing to the desired pressure, and preheating to 25 C from state point 2 to point 3, thus evaporating with approximately 46.9 atm from state point 3 to point 4, and overheated from state point 4 to point 5. At turbine 31, the high pressure the R23 gas is allowed to expand and release energy to produce power, reducing the temperature of the R23 gas to approximately -20 C from state point 5 to point 6 to the pressure 13.9 atm.
The R23 vapor is condensed for rejecting the latent heat from state point 6 to point 1, and then changes its vapor phase back to liquid phase. In this exemplary embodiment, the efficiency of the R23 working fluid APS 10 is approximately 19.1 %. This temperature-entropy (T-S) diagram of this exemplary system indicated that the lower critical temperature hydrofluorocarbons (HFC) or hydrocarbons (HC) working fluid is best suited for use in colder climates to get a higher efficiency.
Page 23 of 32 100901 Fig. 10 is a R23 working fluid saturated pressure-temperature diagram.
Comparing the boiling temperature (100 C) of water, R23 working fluid also has a very low boiling temperature (-82.0 C), a more low critical temperature (26.1 C) and a very high critical pressure (48.3 atm); suggesting that R23 working fluid APS system 10 can also have a very high operating pressure even at a low operating temperature. For the exemplary embodiment, at the evaporating temperature 25 C, the R23 saturated pressure is 46.9 atm, and at the condensing temperature -20 C, the R23 saturated pressure is 13.9 atm, the pressure difference is 33.0 atm between two temperatures, much higher than the other conventional ORC systems.
[00911 FIG. 11 is a plot of the R23 working fluid latent heat-temperature diagram, illustrating thermal characteristic of the R23 working fluid APS system 10. As showed in Fig 11, the R23 working fluid also has a very low latent heat, which is suited to get a higher efficiency of the low temperature applications. For example, at the condense temperature of -20 C, the R23 latent heat is only 12.1 KJ/mol, much less than water latent heat (40.68 KJ/mol) of water; consequently the R23 APS system 10 will have a higher efficiency for APS.
100921 FIG. 12 is a variation of the efficiency of R23 working fluid APS 10 as a function of condenses temperature, with 25 C evaporation temperature (as show in Fig.2a or Fig.2b). The cycle efficiency of the R23 APS 10 depends on the temperature of rejection in the condenser 34.
The efficiency is 5.1% at the normal condense temperature (20 C); while at the cold condense temperature (-20 C), the efficiency will increase to 19.1%. It has been known that when the heat rejection is accomplished by direct air cooling (as show in Fig.lb or Fig.2b) in the low critical temperature hydrofluorocarbons (HFC) or hydrocarbons (HC) working fluid APS
10, a cold climate results in a higher efficiency.
Page 24 of 32 (0093] FIG. 13 is a plot of efficiency of the R23 working fluid air power system 10 versus evaporation temperature, with the same condenses temperature of 0 C (as show in Fig.lb and Fig.2b). The cycle efficiency of the R23 APS 10 will be improved by increasing the evaporation temperature. This shows that in the summer, a hotter climate enables the APS
to achieve a higher efficiency if it is possible to get enough cooling sources (for example, Deep Ocean).
[0094] FIG. 14 is an evaporation temperature-ORC system efficiency diagram of R23, as a working fluid is used in the low temperature organic Rankine cycle air power system, with -20 C condensing temperature for extremely cold climate with cold air (as show in Fig. lb and Fig.2b). Even at the temperature 10 C, the efficiency of this APS 10 is 13.5 %. This shows that the cold climate enables the APS to achieve a higher efficiency with the heat sources from the ground or fluid (about 15 C) 100951 Due to the HFC or HC working fluid's low latent heat and low critical temperature characteristics, the low critical temperature HFC or HC working fluid APS 10 is able to achieve a higher efficiency even in cold winter for the advantages of these thermodynamic properties.
This feature of the low critical temperature HFC or HC working fluid provides a potential to increase the efficiency of this APS 10 in the cold winter. For example, in cold winter, the evaporators 20 can collect thermal energy from well water or river or ocean water; the evaporation temperature could be 10 C with ground heat energy, coupling with the cold air temperature -20 C, the efficiency of the R23 APS 10 is as high as 13.5%.
100961 Another possible embodiment is to generate mechanical energy rather than electrical energy. Direct generation of mechanical energy would be useful to drive an automobile, or a compressor for an air conditioner, or manufacturing equipment.
Page 25 of 32 [0097] Although the present invention has been described with reference to a preferred embodiment, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.
[0098] From the description above, there are a number of advantages about the APS 10: (1) The energy produced using the APS will be generated utilizing the free ambient temperature around the surface of the earth and by the vapor pressure generated by the low critical temperature hydrofluorocarbons (HFC) or hydrocarbons (HC) working fluid with a critical temperature ranges of 10 C. to 45 C. Importantly, the condensation of the working fluid can also be achieved utilizing the cold water without requiring the use of additional input energy. The electrical energy produced by the APS will therefore be very inexpensive. (2) The APS 10 will produce round the clock nonstop electrical energy without disruption. (3) Electrical energy produced with the APS 10 will be produced without utilizing costly fossil fuels or destroying natural resources. (4) Electrical energy will be produced without generating hazardous waste.
Electrical energy is produced without generating air, chemical, radioactive or solid pollutants. (5) Electrical energy produced with APS 10 will not be restricted to daylight hours to produce. The energy does not require the direct power of the sun which can be restrictive due to the time of the year and by the amount of cloud cover. (6) The APS 10 device can be used for large scale electrical energy production for power plant or it can be scaled down to be used for single family homes. (7) The APS 10 can be used at the Arctic/Antarctic or at the equator and all locations (8) The APS 10 can be used in different geographically areas and can be adapted to different geological areas.
[0099] Accordingly, the APS 10 invention is very useful in electrical energy generation. The APS 10 harnesses the environment energy created by sun when working fluid with critical Page 26 of 32 temperature ranges of -5 C. to 45 C, are heated to or above the critical temperature. This heating is accomplished by using the air, ground or fluid temperatures near the surface of the earth. The vapor pressure generated sufficiently drives the turbine which can produce electricity or mechanical energy.
[001001 Although the description above contains many specifications, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention.
1001011 The evaporators or condensers of the APS 10 may be linked to several non-turbine type machines to produce linear or radial motion rather than circular motion to generate energy.
[00102] Thus the scope of the invention should be determined by the appended claims and their legal equivalents, rather than by the examples given.
Page 27 of 32
[00211 The approaches described previously about this patent have all the listed advantages, which extract air, fluid or ground thermal energy for a organic Rankine cycle system with a low critical temperature HFC or HC working fluid, to produce electricity with high efficiency.
Page 6 of 32 Providing a reliable, long-term, cost effective, and efficient way of using clean renewable energy to obtain electrical power that has long been an unsolved problem, until the present invention.
This invention makes it possible to solve energy problem.
100221 With the foregoing in mind, it is a primary object of the present invention to overcome or substantially alleviate long term problems of the prior art by which clean renewable energy is converted to electrical energy efficiently and in an inexpensive manner.
[00231 Another object of the present invention is to provide reliable, cost effective systems and methods for conversion of air, fluid or ground thermal energy to electricity or do other work, where the size of any such system can be correlated to a desired capacity.
[00241 Another important object is to provide systems and methods for the conversion of low temperature thermal energy, wherever obtained, to electrical energy or do other work using a novel organic Rankine cycle system by which a generator is driven or another work performing mechanism is driven, in a cost effective way.
[00251 It is a further valuable object to provide the novel working fluids for organic Rankine cycle system and related methodology.
100261 In brief summary, the present invention overcomes or substantially alleviates long term problems of the prior art by which clean renewable energy is cost effectively converted to electrical energy. The present invention also provides the method and device for conversion of low temperature thermal energy, wherever obtained, to electrical energy using a novel organic Rankine cycle system to drive an electrical generator, in a cost effective way. The novel organic Rankine cycle system can do other work as well. The present invention provides reliable, cost Page 7 of 32 effective ways for conversion of clean renewable energy and other thermal energy to electricity, where the size of the system can be correlated to the desired capacity.
[00271 It has been discovered by this invention, that some low critical temperature working fluids have unique low temperature applications as a working fluid in an organic Rankine cycle system. One example of the preferred working fluids are hydrofluorocarbons (HFC) or hydrocarbons (HC), which has a low critical temperature (LCT) within the typical temperature ranges of 10 C to 45 C, and very low boiling point (LBT). The present invention provides hydrofluorocarbons (HFC) or hydrocarbons (HC), which has a low critical temperature (LCT) within the typical temperature ranges of 10 C to 45 C, and low boiling point (about -80 C), as the organic Rankine cycle working fluid for this air power system (APS).
[00281 These objects and features of the present invention will be apparent from the detailed description taken with reference to accompanying drawings.
SUMMARY OF THE INVENTION
[00291 In accordance with the present invention, an air power system (APS) comprises a method for continuous electrical energy generation. The APS utilizes a working fluid contained within an evaporator. Possible working fluids have low critical temperature ranges of -5 C to 45 C. The evaporator is exposed to outdoor temperatures at or in close proximity to the surface of the earth.
The majority of the surface area of the evaporator is in the open air, in a fluid exposed to outdoor temperatures or the ground. The evaporator can also be exposed to additional supplemental heat source. The APS is not location limited and can use the air temperatures at any location on earth to generate electrical energy. As the temperature of the working fluid increases, the vapor pressure also increases. The vapor pressure causes a turbine to move and energy to be generated.
Page 8 of 32 The fluid is transferred to a condensation condenser using the low cooling temperatures of the air, water or ground to condensate the working fluid. The condensed working fluid is pumped back to the evaporator for the next cycle.
BRIEF DESCRIPTION OF THE DRAWINGS
100301 FIG. la is a schematic illustration of the single air power system, comprising the low critical temperature HFC or HC working fluid ORC power system with one evaporator.
100311 FIG. lb is a schematic illustration of the single air power system, comprising the low critical temperature HFC or HC working fluid ORC power system with one air condenser.
[00321 FIG. 2a is a schematic illustration of the multiple air power system, comprising the low critical temperature HFC or HC working fluid ORC power system with multiple evaporators.
100331 FIG. 2b is a schematic illustration of the multiple air power system, comprising the low critical temperature HFC or HC working fluid ORC power system with multiple condensers.
100341 FIG. 3a is a temperature-entropy (T-S) diagram of R41, a working fluid is used in the air power system with 20 C condensing temperature for hot climate.
100351 FIG. 3b is another temperature-entropy (T-S) diagram of R41, a working fluid is used in the low temperature organic Rankine cycle air power system with 0 C
condensing temperature for cold climate.
Page 9 of 32 [00361 FIG. 3c is another temperature-entropy (T-S) diagram of R41, a working fluid is used in the low temperature organic Rankine cycle air power system with -20 C
condensing temperature for extremely cold climate.
100371 FIG. 4 is a temperature-saturated pressure diagram of R41, as a working fluid is used in the low temperature organic Rankine cycle air power system.
100381 FIG. 5 is a temperature-latent heat diagram of R41, as a working fluid is used in the low temperature organic Rankine cycle air power system.
[00391 FIG. 6 is an evaporation temperature-ORC system efficiency diagram of R41, as a working fluid is used in the low temperature organic Rankine cycle air power system, with 20 C
condensing temperature for hot climate.
[00401 FIG. 7 is an evaporation temperature-ORC system efficiency diagram of R41, as a working fluid is used in the low temperature organic Rankine cycle air power system, with 0 C
condensing temperature for cold climate.
100411 FIG. 8 is an evaporation temperature-ORC system efficiency diagram of R41, as a working fluid is used in the low temperature organic Rankine cycle air power system, with -20 C condensing temperature for extremely cold climate.
[00421 FIG. 9a is another temperature-entropy (T-S) diagram of R23; a working fluid is used in the low temperature organic Rankine cycle air power system, with 0 C
condensing temperature for cold climate.
Page 10 of 32 [00431 FIG. 9b is another temperature-entropy (T-S) diagram of R23; a working fluid is used in the low temperature organic Rankine cycle air power system, with -20 C
condensing temperature for extremely cold climate.
100441 FIG. 10 is a temperature-saturated pressure diagram of R23, as a working fluid is used in the low temperature organic Rankine cycle air power system.
100451 FIG. 11 is a temperature-latent heat diagram of R23, as a working fluid is used in the low temperature organic Rankine cycle air power system.
[00461 FIG. 12 is a condensing temperature-ORC system efficiency diagram of R23, as a working fluid is used in the low temperature organic Rankine cycle air power system, with 25 C
evaporation temperature.
100471 FIG. 13 is an evaporation temperature-ORC system efficiency diagram of R23, as a working fluid is used in the low temperature organic Rankine cycle air power system, with 0 C
condensing temperature for cold climate.
[00481 FIG. 14 is an evaporation temperature-ORC system efficiency diagram of R23, as a working fluid is used in the low temperature organic Rankine cycle air power system, with -20 C condensing temperature for extremely cold climate.
DETAILED DESCRIPTION OF THE INVENTION
100491 The present invention utilizes, in some forms, the free and limitless air, fluid or ground thermal energy to produce electricity. The scale of commercial installations of the present invention can be tailored to the need, ranging from small stand alone systems for residential and Page 11 of 32 small business use to intermediate sized plants for industrial plant or factory use to massive assemblies design to supplement the supply of electricity or to mitigate against if not, eliminate an electrical energy crisis, such as the recent one in Japan. The present invention is economical to install and maintain, and is reliable and not maintenance-intensive, and is efficient and cost effective to operate and does not pollute the environment.
[00501 Using the present invention, businesses, industrial plants, retail and office buildings, homes, farms and villages can produce their own electrical power, and avoid having to pay, the ever-escalating price of purchased electrical power generated from fossil and nuclear fuels.
[00511 This invention is capable of making significantly more energy and efficiency than conventional ORC technologies. Prior art, the ORC systems are incapable of converting the air thermal energy to electricity, but the present invention, can be used to convert electrical energy even with the air thermal energy as well.
100521 The present invention is a better choice, which can be scaled or sized to independently produce as much electrical energy as needed on site, such as the energy needed to power a home or business, pump water, irrigate land and run remote communication installations.
100531 Unlike centralized forms of power generations, de-centralized use of on-site air obtained electrical power needs no far-flung distribution network of gigantic towers and high voltage lines, instead, it utilizes a universally available asset, air thermal energy.
[00541 The cost of the generating equipment itself used in the production of power for a building can be amortized over the life of the building, as part of debt financing (mortgage). Amazing, as it may seem, one of the largest and most uncontrollable costs a building owner faces is the ever Page 12 of 32 escalating cost of electrical power. Using the present invention, one actually has the ability to eliminate the cost of purchased electrical power now and for years to come.
100551 When land and water were plentiful and energy was cheap, little was known about the delicate balance existing between the environment and the extraction, burning, and wasting of non-renewable fuels. Now it is all too apparent that our supply of fossil fuels is limited and that these sources are causing damage to our atmosphere, water supplies, and food chain damage that is or may soon become irreversible. The costs, too, for fossil fuels to continue upward as the more accessible fuel deposits are consumed, and as the costs for machinery, labor, and transportation continue to rise around the world.
[00561 Ironically, the best answer to the world's need for energy has always been the clean renewable energy. The clean renewable energy can completely fulfill our energy requirements while helping us to become independent of the negative aspects inherent in conventional electrical power generation. Switching to air-derived electrical power will reduce the pollution produced by coal, oil and nuclear fuels. It will also stop the use of coal and oil and allow us to conserve these resources for later and perhaps valuable uses. Harnessing the APS will also reduce, or eliminate the need for nuclear power and mitigate its many risks and problems, such as the recent one in Japan.
100571 The present invention is not space-intensive. The APS, in some forms, can be installed on an existing yard so that it essentially takes up no additional space at all.
Ground-mounted systems on a pad or superimposed above a roof or parking lot are also options as well. Deck mounting is a further option.
Page 13 of 32 [00581 Various embodiments of the present invention may be used in conjunction with residences, office buildings, manufacturing facilities, apartment buildings, schools, hospitals, remote communications, telemetry facilities, offshore platforms, water pumping stations, desalination systems, disinfection systems, wilderness camping, headquarters installations, remote medical facilities, refrigeration systems farms and dairies, remote villages, weather stations, and air conditioning systems.
100591 The present invention is also useful: in (a) providing catholic protection against galvanite corrosion, (b) storage of electrical energy in batteries, in some circumstances and (c) generation and sale of electricity to utility companies.
100601 The types of working fluids of the ORC system have a big impact on the efficiency of an organic Rankine cycle air power system for the various thermodynamic cycles in which the turbine operates. Some types of working fluids have been used in organic Rankine cycle in the past, including some refrigerants and hydrocarbons. Generally, the selection of the working fluid will consider the range of heat temperature of an evaporator and heat sink temperature of a condenser in a closed loop of the ORC system. In the present invention, different with past, the low critical temperature hydrofluorocarbons (HFC) or hydrocarbons (HC) are selected as the working fluid to be used in the closed loop of the ORC system, with the HFC or HC working fluids critical temperature ranges of 10 - 45 C, close to air, fluid or ground thermal temperature range of -5 C - 45 C.
100611 The selection of the working fluid is a key importance for this air temperature Rankine cycle system. In order to extract low-grade air, fluid or ground thermal energy, the working fluid must have a much lower boiling point. And a fluid with a low latent heat will have more high Page 14 of 32 efficiency, as it ejects less heat energy to the condenser, thus reduces the required heat, as the results, reduces the cost, for reducing the flow rate, the size of the power facility, and the pump consumption. The freezing point of the selected working fluid should be lower than the lowest temperature in the cycle and also have a low environmental impact.
[00621 Conventional organic Rankine cycle (ORC) is a developed process for conversion low and medium temperature heat to electricity from a temperature range of 80 C -352 C, but there are no conventional ORC systems that can convert low temperature heat to electricity from a temperature range of -5 C - 45 C.
[00631 FIG. la and Fig. l b show a schematic of the air power system 10, which generally includes evaporator 20 and the organic Rankine cycle with a temperature range of -5 C - 45 C.
The evaporator 20 generally includes a circulate pump 22; and plenty of circulation pipes 23.
The ORC system 30 generally includes a turbine 31, a turbine generator 38, a condenser 34, and circulation pipes 36 and a circulate pump 22. In addition, generator 38 and turbine 31 are connected on a shaft 35. The working fluid is pumped and circulated in the closed loop 23 and 26 of ORC system. The power generated by generator 38 may be used in various applications, including, but not limited to: powering commercial, residential house and buildings.
100641 This air power system 10 has evaporator 20. Located within the evaporator is a working fluid with low critical temperature hydrofluorocarbons (HFC) or hydrocarbons (HC) with the critical temperature ranges of 10 - 45 C. Some suitable low critical temperature hydrofluorocarbons (HFC) or hydrocarbons (HC) include, but are not necessarily limited to:
[00651 R23, Fluoroform (CHF3) 100661 R32, Methylene fluoride (CH2F2) Page 15 of 32 100671 R41, Methyl fluoride (CH3F) [00681 R116, Perfluoroethane (CF3CF3) [00691 R1150, Ethylene (CH2CH2) [00701 R170, Ethane (CH3CH3) [00711 The properties comparing between the low critical temperature hydrofluorocarbons (HFC) or hydrocarbons (HC) working fluids are showed in table 1. The low critical temperature hydrofluorocarbons (HFC) or hydrocarbons (HC) working fluids ORC system is able to achieve a high efficiency even at a very low temperature between of -5 C - 40 C, due to its low boiling point, low critical temperature, and small latent heat characteristic. At the low temperature ranges -5 C - 40 C, the low critical temperature hydrofluorocarbons (HFC) or hydrocarbons (HC) working fluids have very high saturated pressure, thus can make more mechanical power at this low temperature. Consequently, the efficiency of APS those the low critical temperature hydrofluorocarbons (HFC) or hydrocarbons (HC) working fluids are higher than other conventional working fluids. Present invention addresses the working fluid with lower critical temperature, and higher pressure at the operating temperature area.
Table 1 Comparison of the low critical temperature HFC and HC
Working Chemical Critical Critical Boiling Latent heat 20 C
fluid formula temperature pressure temperature at 20 C Saturate pressure C MPa C KJ/mol MPa R23 CHF3 26.1 4.83 -82.0 5.3 4.16 R41 CH3F 44.1 5.90 -78.3 8.7 3.40 R116 CF3CF3 19.9 3.05 -78.1 0 3.04 R1150 CH2CH2 9.2 5.04 -103.8 - 5.41 R170 CH3CH3 32.2 4.87 -88.6 6.2 3.76 Page 16 of 32 [00721 The low critical temperature hydrofluorocarbons (HFC) or hydrocarbons (HC) working fluids have many advantages. It is inexpensive, non-explosive, most non-flammable. In addition, it has no ozone depleting potential (ODP) and a low global warming potential (GWP). Due to its relatively high working pressure, the low critical temperature hydrofluorocarbons (HFC) or hydrocarbons (HC) working fluid ORC system is more compact than the system operating with other conventional working fluids.
100731 The evaporator 20 is placed in a position so that the evaporator 20 is exposed to the earth's hot side of the air temperatures, ground temperatures or fluid temperatures. The evaporator 20 has an outlet regulator valve. The regulating valve is connected to a gas turbine 31.
The turbine is linked to a drive shaft 35, which is linked to an electric generator 38. The turbine 31 contains an outlet valve, which connects to a condenser 34. The condenser 34 is placed in a position so that the condenser 34 is exposed to the earth's cold side of the air temperature, fluid temperature or ground temperature. The condenser 34 contains an outlet regulator valve. The outlet regulator valve connects to a fluid pump 22. The fluid pump 22 connects to a one way inlet valve on the evaporator 20. The above system will have one or evaporator/condenser linked each other to one or multiple turbine depending on space restrictions and the desired amount of energy to be generated. The above system will have the capacity to replace the working fluid depending on the environmental temperatures encountered by the evaporator 20 or condenser 34.
The turbines 31 can be any kind of expansion machine, either impulse or reaction type.
[00741 The manner of generating electric energy using an air power system (APS) begins with radiant or conductive heat transfer from the air, ground or fluid to the air tight pressure evaporator 20. The surrounding temperature of the evaporator 20 is in the range of -5 C. to 45 C. The working fluid inside the evaporator 20 has a boiling point much below the ambient Page 17 of 32 temperature. The liquid inside the evaporator 20 increases by increasing evaporating temperature, consequently the vapor pressure inside the evaporator 20 also increases.
100751 Preferably, heat transfer from the ambient environment immediately surrounding the evaporator 20 to the working fluid in the evaporator 20 causes the liquid working fluid to boil or vaporize. This heat transfer is generated solely by the difference in temperature between the ambient environment and the temperature of the working fluid within the evaporator 20.
100761 When sufficient pressure has built within the evaporator 20, the gas is released through a regulator valve with sufficient force to turn a gas turbine 31. As the turbine 31 turns it causes a drive shaft 35 to rotate. The drive shaft 35 is linked to a generator 38 while it rotates and electrical energy is generated. After released energy, the gas flows from the gas turbine 31 into a condenser 34. The condenser 34 is surrounded by temperatures in the range of -30 C. to 20 C.
The gas begins to liquated within the condenser 34. When sufficient gas has condensed, the liquid fluid is released through the regulator valve to a pump 22. The liquid working fluid is pumped back into the one way inlet valve on the evaporator 20 and for the cycle repeats.
[00771 In the summer, the evaporator 20 may be exposed to ambient air temperature and the condenser 34 may be exposed to fluid temperature or ground temperature (Fig.1 a). In winter, the evaporator 20 may be exposed to fluid temperature or ground temperature and the condenser 34 may be exposed to either ambient air temperature, cold fluid temperature or cold ground temperature (Fig.1b). The evaporator 20 also may be exposed to ground temperature and the condenser 34 may be exposed to either ambient air temperature, fluid temperature or cold ground temperature.
Page 18 of 32 [00781 In order to provide more energy production, it is beneficial to have multiple evaporators 20 in operation for hot climate. Fig. 2a is a schematic illustration of the air power system with multiple evaporators, comprising the ORC power system with the low critical temperature HFC
or HC working fluid. This air power system 10 can range in size from 10 KW to 1000 MW; and also, multiple air power systems can be used to form a power plant of any size. The power generated by an air power system 10 may be used in various applications, including, but not limited to: powering commercial and residential buildings.
100791 In order to provide more energy production, it is also beneficial to have multiple condensers 34 in operation for cold climate. Fig. 2b is a schematic illustration of the air power system with multiple air cooling condensers with ground or fluid as heat sources, comprising the ORC power system with the low critical temperature HFC or HC working fluid.
This air power system 10 can range in size from 10 KW to 1000 MW; and also multiple air power systems can be used to form a power plant of any size.
[00801 Fig. 3a is a temperature-entropy (T-S) diagram of R41 APS 10 operations with 20 C
condensing temperature for hot climate (as show in Fig. la and Fig. 2a). The R41 working fluid is pumped while increasing the pressure from state point 1 to point 2, and preheating to approximately 40 C from state point 2 to point 3, thus evaporating to approximately 53.8 atm from state point 3 to point 4 in the evaporator 20, and overheated from state point 4 to point 5.
At turbine 31, the high pressure R41 vapor is allowed to expand and release pressure energy to produce power, reducing the temperature of the R41 vapor to approximately 20 C from state point 5 to point 6, to the pressure approximately 34 atm. From state point 6 to point 1, the R41 vapor is condensed for rejecting the latent heat, and then changes its vapor phase back to liquid phase. In this exemplary embodiment, the efficiency of the R41 APS 10 is approximately 11.8%.
Page 19 of 32 This temperature-entropy (T-S) diagram indicated R41 is best suited working fluid for using in the very hot climate.
100811 Fig. 3b is another temperature-entropy (T-S) diagram of R41 APS 10 operations with 0 C condensing temperature (as show in Fig. Ib and Fig. 2b). The R41 working fluid is pumped while increasing the pressure, from state point 1 to point 2, and preheating to approximately 40 C from state point 2 to point 3, thus evaporating to approximately 53.8 atm from state point 3 to point 4 in the evaporator 20, and overheated from state point 4 to point 5. At turbine 31, the high pressure R41 vapor is allowed to expand and release pressure energy to produce power, reducing the temperature of the R41 vapor to approximately 0 C from state point 5 to point 6 to the pressure approximately 20.4 atm. From state point 6 to point 1, the R41 vapor is condensed for rejecting the latent heat, and then changes its vapor phase back to liquid phase. In this exemplary embodiment, the efficiency of the R41 ORC system 30 is approximately as high as 18%. This temperature-entropy (T-S) diagram indicated R41 has a better efficiency for using with lower condensing temperature.
100821 Fig. 3c is another temperature-entropy (T-S) diagram of R41 APS 10 operations with -20 C condensing temperature (as show in Fig. lb and Fig. 2b). The R41 working fluid is pumped from state point 1 to point 2 while increasing the pressure, and preheating to approximately 40 C from state point 2 to point 3, thus evaporating to approximately 53.8 atm from state point 3 to point 4 in the evaporator 20, and overheated from state point 4 to point 5.
At turbine 31, the high pressure R41 vapor is allowed to expand and release pressure energy to produce power, reducing the temperature of the R41 vapor to approximately -20 C from state point 5 to point 6 to the pressure approximately 11.4 atm. From state point 6 to point 1, the R41 vapor is condensed for rejecting the latent heat, and then changes its vapor phase back to liquid Page 20 of 32 phase. In this exemplary embodiment, the efficiency of the R41 APS 10 is approximately as high as 23%. This temperature-entropy (T-S) diagram indicated R41 has a excellent efficiency for using with very low condensing temperature.
[0083] Fig. 4 is a R41 working fluid saturated pressure-temperature diagram.
Comparing the boiling temperature (100 C) of water, R41 working fluid has a very low boiling point (-78.3 C), a low critical temperature (44.1 C) and a very high critical pressure (59.0 atm); consequently that the low critical temperature R41 working fluid APS system 10 can have a very high operating pressure even at a low operating temperature. For the exemplary embodiment, at the evaporating temperature 40 C, the R41 saturated pressure is 53.8 atm, and at the condensing temperature 10 C, the R41 saturated pressure is 20.5 atm, the pressure difference is 33.3 atm between two temperatures, much higher than other conventional ORC systems. For a turbine system, the pressure difference between the evaporating pressure and condenser pressure is very important to rotate the turbine for mechanical work. This is another reason why low critical temperature HFC or HC working fluid is selected for this air power system 10.
[0084] Fig. 5 is a plot of the R41 working fluid latent heat-temperature diagram, illustrating thermal characteristic of the R41 working fluid APS system 10. As showed in Fig 5, the R41 working fluid has very low latent heat, which is suited to get high efficiency of the low temperature applications. For example, at the condense temperature of 20 C, the R41 latent heat is only 8.8 KJ/mol, much less than water latent heat (40.68 KJ/mol) of water;
consequently the R41 APS system 10 will have a higher efficiency.
[0085] Fig. 6 is a plot of efficiency of the R41 working fluid air power system 10 versus evaporation temperature, with the same condenses temperature 20 C (as show in Fig. 2a and Page 21 of 32 Fig. 2a). The cycle efficiency of the R41 APS 10 shows depending on the temperature of evaporation. At the temperature 30 C, the efficiency of this APS 10 is 6.2 %, and increases to 11.8 % at the evaporation temperature 40 C. This shows that in the summer, a hotter climate (for example in Africa) enable the APS to achieve a higher efficiency.
100861 Fig. 7 is a plot of efficiency of the R41 working fluid air power system 10 versus evaporation temperature, with the same condenses temperature 0 C (as show in Fig. lb and Fig.
2b) The cycle efficiency of the R41 APS 10 will improve by decreaseing the cooling temperature of condenser. This shows that the hot summer is able to achieve a higher efficiency of this APS, if it is possible to get enough cooling sources. For example, the water temperature is close to 0 C in deep ocean even in summer.
[00871 Fig. 8 is an evaporation temperature-ORC system efficiency diagram of R41, as a working fluid is used in the low temperature organic Rankine cycle air power system, with -20 C condensing temperature for extremely cold climate with air as cooling sources (as show in Fig.lb and Fig.2b). At the heating temperature 10 C, the efficiency of this APS 10 is 12.5 %.
This shows that a colder climate enable the APS to achieve a more efficiency with the heat sources from the ground or fluid (about 15 C).
[00881 Fig. 9a is another temperature-entropy (T-S) diagram of R23; another working fluid is used in the low temperature organic Rankine cycle air power system, with 0 C
condensing temperature for APS 10 (as show in Fig.lb and Fig.2b). The R23 working fluid is pumped from state point 1 to point 2 while increasing to the desired pressure, and preheating to 25 C from state point 2 to point 3, thus evaporating with approximately 46.9 atm from state point 3 to point 4, and overheated from state point 4 to point 5. At turbine 31, the high pressure the R23 gas is Page 22 of 32 allowed to expand and release energy to produce power, reducing the temperature of the R23 gas to approximately 0 C from state point 5 to point 6 to the pressure 24.9 atm.
The R23 vapor is condensed for rejecting the latent heat from state point 6 to point 1, and then changes its vapor phase back to a liquid phase. In this exemplary embodiment, the efficiency of the R23 working fluid APS 10 is approximately 13.5 %. This temperature-entropy (T-S) diagram of this exemplary system indicated that the lower critical temperature hydrofluorocarbons (HFC) or hydrocarbons (HC) working fluid is best suited for use in hotter climates to get a higher efficiency with more cooling resources.
100891 Fig. 9b is another temperature-entropy (T-S) diagram of R23; a working fluid is used in the low temperature organic Rankine cycle air power system, with -20 C
condensing temperature for extremely cold climate (as show in Fig. lb and Fig.2b). The R23 working fluid is pumped from state point 1 to point 2 while increasing to the desired pressure, and preheating to 25 C from state point 2 to point 3, thus evaporating with approximately 46.9 atm from state point 3 to point 4, and overheated from state point 4 to point 5. At turbine 31, the high pressure the R23 gas is allowed to expand and release energy to produce power, reducing the temperature of the R23 gas to approximately -20 C from state point 5 to point 6 to the pressure 13.9 atm.
The R23 vapor is condensed for rejecting the latent heat from state point 6 to point 1, and then changes its vapor phase back to liquid phase. In this exemplary embodiment, the efficiency of the R23 working fluid APS 10 is approximately 19.1 %. This temperature-entropy (T-S) diagram of this exemplary system indicated that the lower critical temperature hydrofluorocarbons (HFC) or hydrocarbons (HC) working fluid is best suited for use in colder climates to get a higher efficiency.
Page 23 of 32 100901 Fig. 10 is a R23 working fluid saturated pressure-temperature diagram.
Comparing the boiling temperature (100 C) of water, R23 working fluid also has a very low boiling temperature (-82.0 C), a more low critical temperature (26.1 C) and a very high critical pressure (48.3 atm); suggesting that R23 working fluid APS system 10 can also have a very high operating pressure even at a low operating temperature. For the exemplary embodiment, at the evaporating temperature 25 C, the R23 saturated pressure is 46.9 atm, and at the condensing temperature -20 C, the R23 saturated pressure is 13.9 atm, the pressure difference is 33.0 atm between two temperatures, much higher than the other conventional ORC systems.
[00911 FIG. 11 is a plot of the R23 working fluid latent heat-temperature diagram, illustrating thermal characteristic of the R23 working fluid APS system 10. As showed in Fig 11, the R23 working fluid also has a very low latent heat, which is suited to get a higher efficiency of the low temperature applications. For example, at the condense temperature of -20 C, the R23 latent heat is only 12.1 KJ/mol, much less than water latent heat (40.68 KJ/mol) of water; consequently the R23 APS system 10 will have a higher efficiency for APS.
100921 FIG. 12 is a variation of the efficiency of R23 working fluid APS 10 as a function of condenses temperature, with 25 C evaporation temperature (as show in Fig.2a or Fig.2b). The cycle efficiency of the R23 APS 10 depends on the temperature of rejection in the condenser 34.
The efficiency is 5.1% at the normal condense temperature (20 C); while at the cold condense temperature (-20 C), the efficiency will increase to 19.1%. It has been known that when the heat rejection is accomplished by direct air cooling (as show in Fig.lb or Fig.2b) in the low critical temperature hydrofluorocarbons (HFC) or hydrocarbons (HC) working fluid APS
10, a cold climate results in a higher efficiency.
Page 24 of 32 (0093] FIG. 13 is a plot of efficiency of the R23 working fluid air power system 10 versus evaporation temperature, with the same condenses temperature of 0 C (as show in Fig.lb and Fig.2b). The cycle efficiency of the R23 APS 10 will be improved by increasing the evaporation temperature. This shows that in the summer, a hotter climate enables the APS
to achieve a higher efficiency if it is possible to get enough cooling sources (for example, Deep Ocean).
[0094] FIG. 14 is an evaporation temperature-ORC system efficiency diagram of R23, as a working fluid is used in the low temperature organic Rankine cycle air power system, with -20 C condensing temperature for extremely cold climate with cold air (as show in Fig. lb and Fig.2b). Even at the temperature 10 C, the efficiency of this APS 10 is 13.5 %. This shows that the cold climate enables the APS to achieve a higher efficiency with the heat sources from the ground or fluid (about 15 C) 100951 Due to the HFC or HC working fluid's low latent heat and low critical temperature characteristics, the low critical temperature HFC or HC working fluid APS 10 is able to achieve a higher efficiency even in cold winter for the advantages of these thermodynamic properties.
This feature of the low critical temperature HFC or HC working fluid provides a potential to increase the efficiency of this APS 10 in the cold winter. For example, in cold winter, the evaporators 20 can collect thermal energy from well water or river or ocean water; the evaporation temperature could be 10 C with ground heat energy, coupling with the cold air temperature -20 C, the efficiency of the R23 APS 10 is as high as 13.5%.
100961 Another possible embodiment is to generate mechanical energy rather than electrical energy. Direct generation of mechanical energy would be useful to drive an automobile, or a compressor for an air conditioner, or manufacturing equipment.
Page 25 of 32 [0097] Although the present invention has been described with reference to a preferred embodiment, workers skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the invention.
[0098] From the description above, there are a number of advantages about the APS 10: (1) The energy produced using the APS will be generated utilizing the free ambient temperature around the surface of the earth and by the vapor pressure generated by the low critical temperature hydrofluorocarbons (HFC) or hydrocarbons (HC) working fluid with a critical temperature ranges of 10 C. to 45 C. Importantly, the condensation of the working fluid can also be achieved utilizing the cold water without requiring the use of additional input energy. The electrical energy produced by the APS will therefore be very inexpensive. (2) The APS 10 will produce round the clock nonstop electrical energy without disruption. (3) Electrical energy produced with the APS 10 will be produced without utilizing costly fossil fuels or destroying natural resources. (4) Electrical energy will be produced without generating hazardous waste.
Electrical energy is produced without generating air, chemical, radioactive or solid pollutants. (5) Electrical energy produced with APS 10 will not be restricted to daylight hours to produce. The energy does not require the direct power of the sun which can be restrictive due to the time of the year and by the amount of cloud cover. (6) The APS 10 device can be used for large scale electrical energy production for power plant or it can be scaled down to be used for single family homes. (7) The APS 10 can be used at the Arctic/Antarctic or at the equator and all locations (8) The APS 10 can be used in different geographically areas and can be adapted to different geological areas.
[0099] Accordingly, the APS 10 invention is very useful in electrical energy generation. The APS 10 harnesses the environment energy created by sun when working fluid with critical Page 26 of 32 temperature ranges of -5 C. to 45 C, are heated to or above the critical temperature. This heating is accomplished by using the air, ground or fluid temperatures near the surface of the earth. The vapor pressure generated sufficiently drives the turbine which can produce electricity or mechanical energy.
[001001 Although the description above contains many specifications, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments of this invention.
1001011 The evaporators or condensers of the APS 10 may be linked to several non-turbine type machines to produce linear or radial motion rather than circular motion to generate energy.
[00102] Thus the scope of the invention should be determined by the appended claims and their legal equivalents, rather than by the examples given.
Page 27 of 32
Claims (16)
1. A method and apparatus for generating electrical energy with air thermal energy, fluid thermal energy, or ground thermal energy, consisting of several steps:
(1) a working fluid with the critical temperature between -5° C. to 45° C, and (2) placing the working fluid in a liquid state in the evaporators, and (3) evaporators substantially near the surface of the earth, the evaporators in an hot atmospheric air temperatures, ground temperatures or fluid temperatures at a location substantially near the surface of the earth and positioned irrespective of environmental conditions other than temperature, the hot ambient environment immediately surrounding the evaporators having an hot ambient temperature smaller or greater than the critical temperature of the working fluid and (4) transferring heat from the hot ambient environment surrounding the evaporators into the working fluid, the heat boiling the liquid working fluid in the evaporators to place at least a portion of said liquid working fluid in a gaseous state, said heat transfer driven by the difference in temperature between said hot ambient environment and the working fluid within the evaporators;
(5) flowing the gaseous working fluid from the evaporators through a regulator valve to the turbines and drives the turbines to rotate the generators for producing electricity (6) flowing said gaseous working fluid from the turbines to the condensers and condensing the gaseous working fluid back to a liquid working fluid, and (7) condensers substantially near the surface of the earth, the condenser at an adequate temperature and the evaporation temperature sufficiently, and (8) Pumping the liquid working fluid from the condensers back to the evaporators with a pump from low working pressure to high working pressure, to complete an energy cycle using the working fluid.
(1) a working fluid with the critical temperature between -5° C. to 45° C, and (2) placing the working fluid in a liquid state in the evaporators, and (3) evaporators substantially near the surface of the earth, the evaporators in an hot atmospheric air temperatures, ground temperatures or fluid temperatures at a location substantially near the surface of the earth and positioned irrespective of environmental conditions other than temperature, the hot ambient environment immediately surrounding the evaporators having an hot ambient temperature smaller or greater than the critical temperature of the working fluid and (4) transferring heat from the hot ambient environment surrounding the evaporators into the working fluid, the heat boiling the liquid working fluid in the evaporators to place at least a portion of said liquid working fluid in a gaseous state, said heat transfer driven by the difference in temperature between said hot ambient environment and the working fluid within the evaporators;
(5) flowing the gaseous working fluid from the evaporators through a regulator valve to the turbines and drives the turbines to rotate the generators for producing electricity (6) flowing said gaseous working fluid from the turbines to the condensers and condensing the gaseous working fluid back to a liquid working fluid, and (7) condensers substantially near the surface of the earth, the condenser at an adequate temperature and the evaporation temperature sufficiently, and (8) Pumping the liquid working fluid from the condensers back to the evaporators with a pump from low working pressure to high working pressure, to complete an energy cycle using the working fluid.
2. The invention of claim 1, previously stated that the working fluid is selected from one of the following hydrofluorocarbons (HFC) or hydrocarbons (HC): R23 (Fluoroform), (Methylenefluoride), R41 (Methylfluoride), R1150 (Ethylene), R170 (Ethane)
3. The invention of claim 1, previously stated that the ambient environment surrounding the evaporator is one of: air, fluid and ground.
4. The method of claim 3, previously stated that the fluid for evaporators is the water from a river, stream, lake, ocean, sea or spring.
5. The method of claim 1, previously stated that the evaporators positioned in water, said water is naturally occurring water or man-made water in fluid communication with a naturally occurring body of water.
6. The invention of claim 1, previously stated that the heat of geothermal energy, ground heat energy, surface water of seas, rivers, or oceans or substances which are tempered by surface water heat energy, the heat energy from the condenser of a power station are used as a heat source to make electricity for the low temperature power system or plant.
7. The method of claim 1 previously stated that the evaporator comprises of a plurality of evaporators, each evaporator is connected either in a series or parallel circuit generating electricity with said gaseous working fluid.
8. The method of claim 1 previously stated that the condenser is surrounded by air, fluid or ground having a colder temperature less than the critical temperature of the working fluid whereby heat rejected between such air or ground and the condenser maintains the temperature of the condenser enough below the evaporator temperature of the working fluid.
9. The method of claim 1 previously stated that the fluid for condensers is the water from a river, stream, lake, ocean, sea or spring.
10. The invention of claim 1, previously stated that the deep water of seas, rivers, or oceans or substances which are cooled by deep water, the cold air of winter, the ice are used as cold source for the liquefaction of the low temperature air power system.
11. The method of claim 1 previously stated that the condenser is positioned in water, said water is naturally occurring water or manmade water in fluid communication with a naturally occurring body of water.
12. The method of claim 1 previously stated that the condenser comprises a plurality of condensers, each condenser connected for each other for cooling with said gaseous working fluid.
13. The invention of claim 1, previously stated that the turbine can be a single or multistage turbine, or any kind of expansion machines using low critical temperature working fluid in the range of -5 °C to 45 °C for air power ORC system.
14. The invention of claim 1, can provide an air power system ranging from 1 to 10 kW;
multiple low critical temperature HFC or HC working fluid air power ORC
systems can also be provided to form a power plant of any size over 10 kW for residential house or building.
multiple low critical temperature HFC or HC working fluid air power ORC
systems can also be provided to form a power plant of any size over 10 kW for residential house or building.
15. The invention of claim 1 can provide a large power plant ranging from 10 KW to 1000 MW. The power generated by organic Rankine cycle air power plant may be used in various applications, including, but not limited to: commercial power plant and residential buildings, conjunction with residences, office buildings, manufacturing facilities, apartment buildings, schools, hospitals, remote communications, telemetry facilities, offshore platforms, water pumping stations, desalination systems, disinfection systems, wilderness camping, headquarters installations, remote medical facilities, refrigeration systems farms and dairies, remote villages, weather stations, and air conditioning systems.
16. The invention of claim 1, also provides mechanical energy rather than electrical energy.
Direct generations of mechanical energy are used to drive an automobile, or a compressor for an air conditioner, or manufacturing equipment.
Direct generations of mechanical energy are used to drive an automobile, or a compressor for an air conditioner, or manufacturing equipment.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2744404A CA2744404A1 (en) | 2011-06-27 | 2011-06-27 | Air power system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2744404A CA2744404A1 (en) | 2011-06-27 | 2011-06-27 | Air power system |
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| Publication Number | Publication Date |
|---|---|
| CA2744404A1 true CA2744404A1 (en) | 2012-12-27 |
Family
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2744404A Abandoned CA2744404A1 (en) | 2011-06-27 | 2011-06-27 | Air power system |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR3009613A1 (en) * | 2013-08-06 | 2015-02-13 | Brgm | SYSTEM FOR GENERATING ELECTRIC ENERGY USING GEOTHERMIC DOUBLET |
| DE102014006909B3 (en) * | 2014-05-09 | 2015-07-09 | Maschinenwerk Misselhorn Mwm Gmbh | Arrangement with several heat exchangers and method for vaporizing a working medium |
| WO2019116104A3 (en) * | 2017-12-13 | 2019-08-15 | Zhejiang Planet Rose New Energy Co.,Ltd. | Geothermal energy system and method of producing power using s |
| US11280323B2 (en) | 2017-12-13 | 2022-03-22 | Kang Zhou | Geothermal energy system and method of producing power using same |
-
2011
- 2011-06-27 CA CA2744404A patent/CA2744404A1/en not_active Abandoned
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR3009613A1 (en) * | 2013-08-06 | 2015-02-13 | Brgm | SYSTEM FOR GENERATING ELECTRIC ENERGY USING GEOTHERMIC DOUBLET |
| DE102014006909B3 (en) * | 2014-05-09 | 2015-07-09 | Maschinenwerk Misselhorn Mwm Gmbh | Arrangement with several heat exchangers and method for vaporizing a working medium |
| WO2019116104A3 (en) * | 2017-12-13 | 2019-08-15 | Zhejiang Planet Rose New Energy Co.,Ltd. | Geothermal energy system and method of producing power using s |
| US10895248B2 (en) | 2017-12-13 | 2021-01-19 | Kang Zhou | Geothermal energy system and method of producing power using same |
| US11280323B2 (en) | 2017-12-13 | 2022-03-22 | Kang Zhou | Geothermal energy system and method of producing power using same |
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