CA3091643A1 - Dual output, compression cycle thermal energy conversion process - Google Patents
Dual output, compression cycle thermal energy conversion process Download PDFInfo
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- CA3091643A1 CA3091643A1 CA3091643A CA3091643A CA3091643A1 CA 3091643 A1 CA3091643 A1 CA 3091643A1 CA 3091643 A CA3091643 A CA 3091643A CA 3091643 A CA3091643 A CA 3091643A CA 3091643 A1 CA3091643 A1 CA 3091643A1
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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
A system, method and apparatus providing an improved heat engine. The closed loop system employs a working fluid under high pressure. The system, method, process and apparatus, includes a heat engine with a heat source and a heat sink. The heat sink for the heat engine provided by a heat exchanger supplied by a cold source that can include ambient air temperatures including Arctic or Antarctic temperatures as low as -75oC, or liquid nitrogen or liquid natural gas. The thermal exchange fluid operating as low as -110oC. The secondary cycle using liquid nitrogen or liquid natural gas passed through an expansion engine which uses the heat sink of the heat engine as its heat source, thereby increasing the overall efficiency of the heat engine by lowering the temperature of its heat sink to obtain a greater thermodynamic efficiency. The process allows for the partial transfer of working fluid mass between the two vessels in each module to increase the efficiency of the process; and increase and decrease the pressures of each vessel exponentially during the cycle. The process allows efficient economic use of ambient temperatures or waste heat, or geothermal heat as heat sources and the use of stored liquid nitrogen or liquid natural gas (LNG)for on-demand use.
Description
Field This invention relates to devices and improved methods for converting thermal energy into mechanical energy. In particular, this invention relates to improving the efficiency of a heat engine over a wider range of temperatures and enabling an energy storage synergy.
Background Thermal energy exists in all environments and is often produced as a by-product in industrial and commercial processes. Natural and waste thermal energy may be used as an input to a heat engine to produce mechanical energy; for instance, as an input to an electrical generator or hydraulic motor. The efficiency of the heat engine is an important factor in determining the economic viability of building a heat engine to use naturally existing, or waste thermal energy as an input. Efficiency is not only defined as thermodynamic efficiency, but as capital cost per Kwh.
Existing thermal engines such as Organic Rankine Cycles are not capable of reaching the lower heat sink temperatures and making use of their thermal benefits as they are impeded by change of state working fluids. Likewise, Stirling engines have only novelty value at low temperature differentials.
A second factor affecting heat engines is that due to daily consumption patterns, it is economically advantageous to not produce and use electricity during periods of low consumption and to make electricity available during periods of high consumption when electricity prices and demand are high.
Many generating sources generate during times when the demand is not aligned with the supply. For example, wind generation can be most
Background Thermal energy exists in all environments and is often produced as a by-product in industrial and commercial processes. Natural and waste thermal energy may be used as an input to a heat engine to produce mechanical energy; for instance, as an input to an electrical generator or hydraulic motor. The efficiency of the heat engine is an important factor in determining the economic viability of building a heat engine to use naturally existing, or waste thermal energy as an input. Efficiency is not only defined as thermodynamic efficiency, but as capital cost per Kwh.
Existing thermal engines such as Organic Rankine Cycles are not capable of reaching the lower heat sink temperatures and making use of their thermal benefits as they are impeded by change of state working fluids. Likewise, Stirling engines have only novelty value at low temperature differentials.
A second factor affecting heat engines is that due to daily consumption patterns, it is economically advantageous to not produce and use electricity during periods of low consumption and to make electricity available during periods of high consumption when electricity prices and demand are high.
Many generating sources generate during times when the demand is not aligned with the supply. For example, wind generation can be most
2 Date Recue/Date Received 2020-08-31 productive at night, but demand may be highest in the day, particularly on hot summer days when air-conditioning demand is high but there may not be any wind. Solar power generation is at the mercy of daylight hours and even then, cloud cover often interferes with its output.
Due to these impediments which hinder the use of more renewable energy, there have been a number of technologies developed to store the energy produced during inconvenient hours, relative to demand.
Some examples of storage include batteries, hydrogen, flywheels, pumped-hydro, compressed air, and gravity.
Generally, the cost of storing energy is much higher than the cost to produce it; and necessitates its use when the hourly market price per Kwh is at its highest, and the cost of storing it at its lowest.
It is therefore desirable to develop storage and generation technologies that minimize the gap between the cost to produce and the cost of storage.
The present invention describes a dual output thermal engine that utilizes a heat engine in combination with a liquid nitrogen or liquid natural gas expander engine which operate synergistically to produce electricity economically during periods of high demand, thereby reducing the cost of producing backup energy in times of peak demand. Additionally, to provide a method of providing liquid nitrogen or hydrogen from naturally occurring thermal differentials or wasted industrial heat by means of benign electricity production, which is then used to produce hydrogen or facilitate other storage methods.
Brief Description of the Drawings In drawings which illustrate by way of example only a preferred embodiment of the invention, Figure 1 is a schematic illustration of a preferred embodiment of the present invention including the dual output combined cycle
Due to these impediments which hinder the use of more renewable energy, there have been a number of technologies developed to store the energy produced during inconvenient hours, relative to demand.
Some examples of storage include batteries, hydrogen, flywheels, pumped-hydro, compressed air, and gravity.
Generally, the cost of storing energy is much higher than the cost to produce it; and necessitates its use when the hourly market price per Kwh is at its highest, and the cost of storing it at its lowest.
It is therefore desirable to develop storage and generation technologies that minimize the gap between the cost to produce and the cost of storage.
The present invention describes a dual output thermal engine that utilizes a heat engine in combination with a liquid nitrogen or liquid natural gas expander engine which operate synergistically to produce electricity economically during periods of high demand, thereby reducing the cost of producing backup energy in times of peak demand. Additionally, to provide a method of providing liquid nitrogen or hydrogen from naturally occurring thermal differentials or wasted industrial heat by means of benign electricity production, which is then used to produce hydrogen or facilitate other storage methods.
Brief Description of the Drawings In drawings which illustrate by way of example only a preferred embodiment of the invention, Figure 1 is a schematic illustration of a preferred embodiment of the present invention including the dual output combined cycle
3 Date Recue/Date Received 2020-08-31 Figure 2 shows the dual acting hydraulic accumulator arrangement, valves, transmission, and generator configuration of the present invention;
Figure 3 shows the dual acting hydraulic accumulator arrangement in valve position 1;
Figure 4 shows the dual acting hydraulic accumulator arrangement in valve position 2;
Figure 5 is a schematic illustration of the liquid nitrogen or liquid natural gas expander engine or 300;
Figure 6 shows the hydraulic accumulator arrangement in valve position 1 of the expander engine process;
Figure 7 shows the hydraulic accumulator arrangement in position 2 of the expander engine process Detailed Description In an implementation, a Heat Engine is provided that is operable to extract thermal energy between a first thermal source and a second thermal source and converting this energy into mechanical energy that can be used to generate electrical energy or drive compressors for energy storage, or direct use, or to feed into a power grid. The thermal sources are put in fluid communication with two vessels containing a gas under pressure. The thermal sources have thermal values that are different than the thermal values of the vessels. The thermal sources are used to alternately increase the temperature and pressure in one of the vessels and decrease the temperature and pressure in the other vessel. A pressure driven pair of hydraulic accumulators are activated in a single direction by the resulting pressure and mass released by the first vessel and the suction from the second vessel. During the process a partial re-distribution of the mass in the heated vessel to the cooled vessel takes place. A reversal of the heating and
Figure 3 shows the dual acting hydraulic accumulator arrangement in valve position 1;
Figure 4 shows the dual acting hydraulic accumulator arrangement in valve position 2;
Figure 5 is a schematic illustration of the liquid nitrogen or liquid natural gas expander engine or 300;
Figure 6 shows the hydraulic accumulator arrangement in valve position 1 of the expander engine process;
Figure 7 shows the hydraulic accumulator arrangement in position 2 of the expander engine process Detailed Description In an implementation, a Heat Engine is provided that is operable to extract thermal energy between a first thermal source and a second thermal source and converting this energy into mechanical energy that can be used to generate electrical energy or drive compressors for energy storage, or direct use, or to feed into a power grid. The thermal sources are put in fluid communication with two vessels containing a gas under pressure. The thermal sources have thermal values that are different than the thermal values of the vessels. The thermal sources are used to alternately increase the temperature and pressure in one of the vessels and decrease the temperature and pressure in the other vessel. A pressure driven pair of hydraulic accumulators are activated in a single direction by the resulting pressure and mass released by the first vessel and the suction from the second vessel. During the process a partial re-distribution of the mass in the heated vessel to the cooled vessel takes place. A reversal of the heating and
4 Date Recue/Date Received 2020-08-31 cooling cycle causes the pair of hydraulic accumulators to move in the opposite direction. The motions of both actions drive a hydraulic motor which in turn drives a generator or compressor.
An apparatus for converting a differential in thermal energy between a first thermal source having a thermal conducting fluid and a second thermal source having a thermal conducting fluid, the apparatus comprising:
= a first vessel for containing a gas under pressure, the first vessel being in fluid communication with said first and second thermal sources;
= a second vessel for containing gas under pressure, the second vessel being in fluid communication with said first and second thermal sources;
= a multiple of two vessel modules in series which comprises a preferred embodiment A plurality of cooperating valves for alternately regulating a flow of thermal conducting fluid from the first and second thermal sources to the first and second vessels, the plurality of cooperating valves alternating between the first and second operating positions, the plurality of cooperating valves permitting a flow of thermal conducting fluid from the first thermal source to the first vessel and from the second vessel in first operating position, the plurality of cooperating valves preventing a flow of thermal conducting fluid from the first thermal source to the second vessel and from the second thermal source to the first vessel in the first operating position, the plurality of cooperating valves permitting a flow of thermal conducting fluid from the first thermal source to the second vessel and from the second thermal source to the first vessel in the second operating position, the plurality of cooperating valves preventing a flow of thermal conducting fluid from the first thermal source to the first vessel and from the second thermal source to the second vessel.
Date Recue/Date Received 2020-08-31 A pressure driven pair of hydraulic accumulators in fluid communication with the first and second vessels whereby the hydraulic accumulators are driven into reciprocating motion between a first position and a second position by alternating positive pressure and negative pressure from the first and second vessels wherein positive pressure from the first vessel coupled with negative pressure from the second vessel when the plurality of cooperating valves is in the first operating position drives the accumulators to the first position and negative pressure from the first vessel coupled with positive pressure from the second vessel when the plurality of cooperating valves is in the second operating position drives the actuator or hydraulic accumulators to the second position.
According to another aspect there is provided a method for converting a differential in thermal energy to mechanical energy comprising the following steps:
= providing first and second vessels containing a gas under pressure, the gas under pressure being of a temperature T;
= providing a first thermal source and a second thermal source, the first thermal source housing a thermal transfer fluid of a temperature above T and the second thermal source housing a thermal transfer fluid of a temperature below T.
= delivering the thermal transfer fluid from the first thermal source to the first vessel thereby raising the pressure of the gas in the first vessel;
= delivering the thermal transfer fluid from the second thermal source to the second vessel thereby lowering the pressure of the gas in the second vessel;
= delivering gas under pressure from the first vessel to a pressure activated pair of hydraulic accumulators and applying suction from the second vessel to the pressure activated piston or hydraulic accumulators thereby causing the pressure activated piston or hydraulic accumulators to move in a first direction.
The hydraulic accumulator embodiment/arrangement of the nitrogen or LNG
expander engine provides a method for extracting the heat from the heat sink of the Date Recue/Date Received 2020-08-31 heat engine and using it in the process of returning the liquid nitrogen or LNG to the gaseous state and harnessing the expansion that occurs in the process.
The integration of both parts provide a novel integrated system that creates a synergy of two power generation methods that increases the overall efficiency of the two methods compared to the sum of the individual efficiencies on their own without being integrated.
In an implementation, a thermal engine is implemented in combination with a liquid nitrogen or liquid natural gas (LNG) expander engine. The heat engine and the expander engine are combined by using the liquid nitrogen or LNG source of the expander engine as a heat sink for the heat engine, allowing the system to use a lower temperature heat source and improve the Carnot efficiency of the system as a whole.
In an implementation, the liquid nitrogen source may be re-supplied using low cost energy during off-peak periods and may be expanded through the expander engine at another time during periods of high energy consumption, improving the economics of the system. Accordingly, the liquid nitrogen source further provides for an energy storage that allows for improved energy generation efficiency during peak periods of consumption.
In an implementation, natural gas that has been liquified can be used as the heat sink for the heat engine and expanded through the expander engine to generate electricity thereby recovering much of the cost of the liquefaction process.
In an aspect, the expansion engine comprises at least one pressure vessel for receiving the liquid nitrogen or liquid natural gas and storing them in a gaseous state, and releasing the stored nitrogen or liquid natural gas in a gaseous state and releasing the stored gas as a second working fluid into a second pressure driven set of hydraulic accumulators which drive the hydraulic motor connected to an electrical generator or compressor.
Date Recue/Date Received 2020-08-31 An apparatus is provided for converting a differential in thermal energy between two thermal sources into mechanical energy that can be used for a wide range of applications known to a person skilled in the art including the generation and storage of electrical energy, or storing the means to enable the production of electrical energy in the form of liquid nitrogen or liquid natural gas as a heat sink enhancer.
An embodiment is shown in Figure 1. Part A, 200 includes a first vessel 2 and a second vessel 4. Each of the two vessels is preferably a sealed container that defines a chamber therein for containing a gas under pressure. As shown in Figure 1, the first vessel 2 defines a chamber 3 and the second vessel 4 defines a chamber 5.
The vessels contain the gas under pressure in the chambers.
The vessels are shown in longitudinal cross-section in Figure 1. Each of the vessels preferably has an insulating jacket 72 for preventing thermal exchange with the ambient environment.
The first vessel 2 has a heat exchange conduit 10 located in the chamber 3.
The conduit is preferably a tube bundle consisting of stainless steel tubing that is adapted to conduct a fluid. Other conduits known in the art to have favourable heat exchanging properties may also be employed in alternate embodiments. The conduit 10 has a first end 30 that communicates with the exterior of the vessel 2 through an opening 31 defined by vessel 2. The conduit 10 has a second end 32 that communicates with the exterior of the vessel 2 through an opening 33 defined by the vessel 2. Similarly, the second vessel 4 has a heat exchange conduit 12 located in the chamber 5. The conduit 12 is also preferably a tube bundle consisting of stainless steel tubing that is adapted to conduct a fluid. Again, other conduits known in the art to have favourable heat exchanging properties may also be employed in alternate embodiments. The conduit 12 has a first end 34 that communicates with the exterior of the vessel 4 through an opening 35 defined by the vessel 4.
The conduit 12 has a second end 36 that communicates with the exterior of the vessel 4 Date Recue/Date Received 2020-08-31 through an opening 37 defined by the vessel 12. Vessel 2 has a pressure sensor 102.
Vessel 4 has a pressure sensor 104.
The heat engine assembly 1, in Figure 1 further includes a thermal heat source 6 and a thermal heat sink 8. The thermal source and sink are shown in Figure 1. Preferably, the thermal source and thermal sink define an interchanger conduit running through them for passage of the thermal conducting fluid and to transfer the heat to or from the heat source or sink. The thermal delivery fluid is preferably an environmentally suitable fluid that can operate between temperatures of -100oC
and +250oC or various other temperature differentials.
The thermal sources can be any medium that is capable of storing or transferring thermal energy to or from the thermal conducting fluid. Among the examples of possible thermal sources include ambient outside air, outside soil, water heated by energy produced by natural gas combustion, wood combustion, solar energy or geothermal energy, or industrial waste heat. Sample examples of thermal sinks include ambient outside air, water, liquid nitrogen, or liquified natural gas.
A thermal fluid-conducting heat supply conduit 42 communicates between the thermal source 6 and the first vessel 2. The conduit 42 further communicates between thermal source 6 and the second vessel 4. A fork 43 in the conduit 42 separates the conduit into a first branch leading to the first vessel 2 and a second branch leading to the second vessel 4.
A thermal fluid-conducting conduit 44 communicates between thermal sink 8 and vessels 2 and 4. A fork 45 in the conduit 44 separates the conduit into a first branch leading to the first vessel 2 and a second branch leading to the second vessel 4.
A thermal fluid-conducting heat sink supply conduit 38a communicates between liquid nitrogen or liquid natural gas heat sink reservoir 170 and heat sink 8.
Date Recue/Date Received 2020-08-31 The conduit 38b communicates between vessels 2 and 4 and the thermal sink 8. A fork 39 in the conduit 38b separates the conduit into a branch leading from the first vessel 2 and another branch leading from the second vessel 4.
A thermal fluid-conducting conduit 40 communicates between the first vessel 2 and the thermal source 6. The conduit 40 further communicates between the second vessel 4 and the thermal source 6. A fork 41 in the conduit 40 separates the conduit into a branch leading from the first vessel 2 and another branch leading from the second vessel 4.
A first valve 14 controls the flow of fluid from the thermal unit 6 to the conduit 10. A second valve 26 controls the flow of fluid from the thermal unit 6 to the conduit 12. A third valve 22 controls the flow of fluid from the thermal unit 8 to the conduit 10. A fourth valve 18 controls the flow of fluid from the thermal unit 8 to the conduit 12. A fifth valve 16 controls the flow of fluid from the conduit 10 to the thermal unit 6. A sixth valve 24 controls the flow of fluid from the conduit 10 to the thermal unit 8. A seventh valve 28 controls the flow of fluid from the conduit 12 to the thermal unit 6. An eighth valve 20 controls the flow of fluid from the conduit 12 to the thermal unit 8. Preferably the valves are electronically operated ball or piston valves although other valves known in the art may also be employed. In an alternate embodiment, cam or linear actuator operated piston valves may be used, particularly in a multi-module engine, in order to ensure synchronization of the pistons and valves. Controller 70 is operatively connected to the valves for opening and closing the valves as required. The eight valves described herein together with the controller comprise a plurality of cooperating valves for alternately regulating a flow of thermal energy from the heat source and heat sink to the first and second vessels.
To avoid unnecessary heat loss during cycling between the two pressure vessels in each module, the in valve and out valves are timed to allow the return of the respective heating and cooling fluids to their source before the incoming fluid reaches the out port of the respective vessel.
Date Recue/Date Received 2020-08-31 Preferably, pump 46 and pump 48 pump the thermal fluids through the thermal fluid conducting conduits. The pumps 46, 48 are preferably circulating pumps.
Vessel 2 further defines an opening 53. A pressure conduit 54 is received in the opening 53 and communicates between the chamber 3 and the exterior of the vessel 2 for delivering gas from the chamber 3 to the exterior and vice versa.
Similarly, vessel 4 further defines an opening 55. A pressure conduit 56 communicates between the chamber 5 and the exterior of the vessel 4 for delivering gas from the chamber to the exterior and vice versa.
As shown in Figure 2, the hydraulic accumulators 58a and 58b have hydraulic fluid chambers 74 moveably received therein. The hydraulic accumulators 58a and 58b define chambers 106 and 108 respectively. Each of the pressure conduits 130 and 134 preferably communicate with the first chamber 106 of hydraulic accumulator 58a. Similarly, each of the pressure conduits 132 and communicate with the second chamber 108 of hydraulic accumulator 58b. The chambers 74 are connected to a diversionary valve 79 as shown in Figure 2, and the diversionary valve 79 is connected to a hydrostatic transmission or hydraulic gearmotor 80 connected to a generator or compressor. A valve 50 is located at the junction of conduits 130, 132, and 54 leading from vessel 2 and the hydraulic accumulators 58a and 58b for regulating gas flow. Similarly, valve 52 is located at the junction of conduits 136, 134, and 56 leading from vessel 4 and the hydraulic accumulators 58a and 58b for regulating gas flow. A valve 138 is located in the pressure conduit 134 between the vessel 4 and the hydraulic accumulator 58a for regulating gas flow. Similarly, valve 140 is located in the pressure conduit between vessel 2 and the hydraulic accumulator 58b.
Hydrostatic transmission 80 is preferably coupled to the diversionary valve 79. The transmission can be coupled to a flywheel and generator combination.
Vessel 2 is connected to the pressure conduit 54. Pressure conduit 54 feeds into pressure conduits 130 and 132. Valve 50 is located between conduit 54 and the Date Recue/Date Received 2020-08-31 conduits 130 and 132. Similarly, vessel 4 is connected to the pressure conduit 56.
Pressure conduit 56 feeds into pressure conduits 134 and 136. Valve 52 is located between conduit 56 and conduits 134 and 136. Valve 138 is located between conduit 134 and the hydraulic accumulator 58a leading to chamber 106.
Similarly, valve 140 is located between conduit 132 and hydraulic accumulator 58b leading to chamber 108.
In its operation, the apparatus reciprocates between a first valve position as shown in Figure 3 and a second valve position as shown in Figure 4 thereby driving the hydrostatic transmission. The reciprocal motion can be transformed into mechanical energy, which in turn can drive a generator or compressor for example.
The controller 70 controls the opening and closing of the valves of the plurality of co-operating valves. To begin the cycle whereby the apparatus moves to the first operating position, the controller opens valve 14 and closes valve 26 so that warm or hot thermal transfer fluid from the heat source 6 flows through thermal fluid conduit 42 to opening 31 and into the heat exchange conduit 10 of the vessel 2.
As the heated thermal transfer fluid flows through conduit 10 in the chamber 3, heat is transferred from the conduit to the surrounding gas in the chamber 3. This causes the pressure of the gas to increase. An acceptable pressure range of the gas for the purposes of the invention is approximately 150 psi to 5000 psi. The controller opens valve 16 and closes valve 24 so that the thermal transfer fluid can flow through the opening 33 through thermal fluid conduit 40 and back to the heat source 6 where the thermal transfer fluid is re-heated.
In addition to opening valve 14 and closing valve 26, the controller simultaneously opens valve 18 and closes valve 22 so that cool thermal transfer fluid from the heat sink 8 flows through conduit 44 to opening 35 and into heat exchange conduit 12 of vessel 4. As the cool thermal transfer fluid flows through the conduit 12 in the chamber 5, heat is transferred from the surrounding gas in the chamber 5 to the conduit. This causes the pressure of the gas to decrease. The controller opens valve 20 and closes valve 28 so that the thermal transfer fluid can Date Recue/Date Received 2020-08-31 flow through the opening 37. The thermal transfer fluid flows through thermal fluid conduit 38b and back to heat sink 8 where the fluid is re-cooled.
When maximum thermal transfer has occurred in the two vessels, the controller 70 will open the pressure valves 50 and 52. In valve position 1, Figure 3, the increased pressure in the vessel 2 will cause the gas from the chamber 3 to flow through the pressure conduit 54 to valve 50 and through conduit 130 to chamber 106 of the hydraulic accumulator 58a. At the same time, the decreased pressure in the vessel 4 will cause the gas from the second chamber 108 of the hydraulic accumulator 58b to flow through the pressure conduit 136 and into the chamber
An apparatus for converting a differential in thermal energy between a first thermal source having a thermal conducting fluid and a second thermal source having a thermal conducting fluid, the apparatus comprising:
= a first vessel for containing a gas under pressure, the first vessel being in fluid communication with said first and second thermal sources;
= a second vessel for containing gas under pressure, the second vessel being in fluid communication with said first and second thermal sources;
= a multiple of two vessel modules in series which comprises a preferred embodiment A plurality of cooperating valves for alternately regulating a flow of thermal conducting fluid from the first and second thermal sources to the first and second vessels, the plurality of cooperating valves alternating between the first and second operating positions, the plurality of cooperating valves permitting a flow of thermal conducting fluid from the first thermal source to the first vessel and from the second vessel in first operating position, the plurality of cooperating valves preventing a flow of thermal conducting fluid from the first thermal source to the second vessel and from the second thermal source to the first vessel in the first operating position, the plurality of cooperating valves permitting a flow of thermal conducting fluid from the first thermal source to the second vessel and from the second thermal source to the first vessel in the second operating position, the plurality of cooperating valves preventing a flow of thermal conducting fluid from the first thermal source to the first vessel and from the second thermal source to the second vessel.
Date Recue/Date Received 2020-08-31 A pressure driven pair of hydraulic accumulators in fluid communication with the first and second vessels whereby the hydraulic accumulators are driven into reciprocating motion between a first position and a second position by alternating positive pressure and negative pressure from the first and second vessels wherein positive pressure from the first vessel coupled with negative pressure from the second vessel when the plurality of cooperating valves is in the first operating position drives the accumulators to the first position and negative pressure from the first vessel coupled with positive pressure from the second vessel when the plurality of cooperating valves is in the second operating position drives the actuator or hydraulic accumulators to the second position.
According to another aspect there is provided a method for converting a differential in thermal energy to mechanical energy comprising the following steps:
= providing first and second vessels containing a gas under pressure, the gas under pressure being of a temperature T;
= providing a first thermal source and a second thermal source, the first thermal source housing a thermal transfer fluid of a temperature above T and the second thermal source housing a thermal transfer fluid of a temperature below T.
= delivering the thermal transfer fluid from the first thermal source to the first vessel thereby raising the pressure of the gas in the first vessel;
= delivering the thermal transfer fluid from the second thermal source to the second vessel thereby lowering the pressure of the gas in the second vessel;
= delivering gas under pressure from the first vessel to a pressure activated pair of hydraulic accumulators and applying suction from the second vessel to the pressure activated piston or hydraulic accumulators thereby causing the pressure activated piston or hydraulic accumulators to move in a first direction.
The hydraulic accumulator embodiment/arrangement of the nitrogen or LNG
expander engine provides a method for extracting the heat from the heat sink of the Date Recue/Date Received 2020-08-31 heat engine and using it in the process of returning the liquid nitrogen or LNG to the gaseous state and harnessing the expansion that occurs in the process.
The integration of both parts provide a novel integrated system that creates a synergy of two power generation methods that increases the overall efficiency of the two methods compared to the sum of the individual efficiencies on their own without being integrated.
In an implementation, a thermal engine is implemented in combination with a liquid nitrogen or liquid natural gas (LNG) expander engine. The heat engine and the expander engine are combined by using the liquid nitrogen or LNG source of the expander engine as a heat sink for the heat engine, allowing the system to use a lower temperature heat source and improve the Carnot efficiency of the system as a whole.
In an implementation, the liquid nitrogen source may be re-supplied using low cost energy during off-peak periods and may be expanded through the expander engine at another time during periods of high energy consumption, improving the economics of the system. Accordingly, the liquid nitrogen source further provides for an energy storage that allows for improved energy generation efficiency during peak periods of consumption.
In an implementation, natural gas that has been liquified can be used as the heat sink for the heat engine and expanded through the expander engine to generate electricity thereby recovering much of the cost of the liquefaction process.
In an aspect, the expansion engine comprises at least one pressure vessel for receiving the liquid nitrogen or liquid natural gas and storing them in a gaseous state, and releasing the stored nitrogen or liquid natural gas in a gaseous state and releasing the stored gas as a second working fluid into a second pressure driven set of hydraulic accumulators which drive the hydraulic motor connected to an electrical generator or compressor.
Date Recue/Date Received 2020-08-31 An apparatus is provided for converting a differential in thermal energy between two thermal sources into mechanical energy that can be used for a wide range of applications known to a person skilled in the art including the generation and storage of electrical energy, or storing the means to enable the production of electrical energy in the form of liquid nitrogen or liquid natural gas as a heat sink enhancer.
An embodiment is shown in Figure 1. Part A, 200 includes a first vessel 2 and a second vessel 4. Each of the two vessels is preferably a sealed container that defines a chamber therein for containing a gas under pressure. As shown in Figure 1, the first vessel 2 defines a chamber 3 and the second vessel 4 defines a chamber 5.
The vessels contain the gas under pressure in the chambers.
The vessels are shown in longitudinal cross-section in Figure 1. Each of the vessels preferably has an insulating jacket 72 for preventing thermal exchange with the ambient environment.
The first vessel 2 has a heat exchange conduit 10 located in the chamber 3.
The conduit is preferably a tube bundle consisting of stainless steel tubing that is adapted to conduct a fluid. Other conduits known in the art to have favourable heat exchanging properties may also be employed in alternate embodiments. The conduit 10 has a first end 30 that communicates with the exterior of the vessel 2 through an opening 31 defined by vessel 2. The conduit 10 has a second end 32 that communicates with the exterior of the vessel 2 through an opening 33 defined by the vessel 2. Similarly, the second vessel 4 has a heat exchange conduit 12 located in the chamber 5. The conduit 12 is also preferably a tube bundle consisting of stainless steel tubing that is adapted to conduct a fluid. Again, other conduits known in the art to have favourable heat exchanging properties may also be employed in alternate embodiments. The conduit 12 has a first end 34 that communicates with the exterior of the vessel 4 through an opening 35 defined by the vessel 4.
The conduit 12 has a second end 36 that communicates with the exterior of the vessel 4 Date Recue/Date Received 2020-08-31 through an opening 37 defined by the vessel 12. Vessel 2 has a pressure sensor 102.
Vessel 4 has a pressure sensor 104.
The heat engine assembly 1, in Figure 1 further includes a thermal heat source 6 and a thermal heat sink 8. The thermal source and sink are shown in Figure 1. Preferably, the thermal source and thermal sink define an interchanger conduit running through them for passage of the thermal conducting fluid and to transfer the heat to or from the heat source or sink. The thermal delivery fluid is preferably an environmentally suitable fluid that can operate between temperatures of -100oC
and +250oC or various other temperature differentials.
The thermal sources can be any medium that is capable of storing or transferring thermal energy to or from the thermal conducting fluid. Among the examples of possible thermal sources include ambient outside air, outside soil, water heated by energy produced by natural gas combustion, wood combustion, solar energy or geothermal energy, or industrial waste heat. Sample examples of thermal sinks include ambient outside air, water, liquid nitrogen, or liquified natural gas.
A thermal fluid-conducting heat supply conduit 42 communicates between the thermal source 6 and the first vessel 2. The conduit 42 further communicates between thermal source 6 and the second vessel 4. A fork 43 in the conduit 42 separates the conduit into a first branch leading to the first vessel 2 and a second branch leading to the second vessel 4.
A thermal fluid-conducting conduit 44 communicates between thermal sink 8 and vessels 2 and 4. A fork 45 in the conduit 44 separates the conduit into a first branch leading to the first vessel 2 and a second branch leading to the second vessel 4.
A thermal fluid-conducting heat sink supply conduit 38a communicates between liquid nitrogen or liquid natural gas heat sink reservoir 170 and heat sink 8.
Date Recue/Date Received 2020-08-31 The conduit 38b communicates between vessels 2 and 4 and the thermal sink 8. A fork 39 in the conduit 38b separates the conduit into a branch leading from the first vessel 2 and another branch leading from the second vessel 4.
A thermal fluid-conducting conduit 40 communicates between the first vessel 2 and the thermal source 6. The conduit 40 further communicates between the second vessel 4 and the thermal source 6. A fork 41 in the conduit 40 separates the conduit into a branch leading from the first vessel 2 and another branch leading from the second vessel 4.
A first valve 14 controls the flow of fluid from the thermal unit 6 to the conduit 10. A second valve 26 controls the flow of fluid from the thermal unit 6 to the conduit 12. A third valve 22 controls the flow of fluid from the thermal unit 8 to the conduit 10. A fourth valve 18 controls the flow of fluid from the thermal unit 8 to the conduit 12. A fifth valve 16 controls the flow of fluid from the conduit 10 to the thermal unit 6. A sixth valve 24 controls the flow of fluid from the conduit 10 to the thermal unit 8. A seventh valve 28 controls the flow of fluid from the conduit 12 to the thermal unit 6. An eighth valve 20 controls the flow of fluid from the conduit 12 to the thermal unit 8. Preferably the valves are electronically operated ball or piston valves although other valves known in the art may also be employed. In an alternate embodiment, cam or linear actuator operated piston valves may be used, particularly in a multi-module engine, in order to ensure synchronization of the pistons and valves. Controller 70 is operatively connected to the valves for opening and closing the valves as required. The eight valves described herein together with the controller comprise a plurality of cooperating valves for alternately regulating a flow of thermal energy from the heat source and heat sink to the first and second vessels.
To avoid unnecessary heat loss during cycling between the two pressure vessels in each module, the in valve and out valves are timed to allow the return of the respective heating and cooling fluids to their source before the incoming fluid reaches the out port of the respective vessel.
Date Recue/Date Received 2020-08-31 Preferably, pump 46 and pump 48 pump the thermal fluids through the thermal fluid conducting conduits. The pumps 46, 48 are preferably circulating pumps.
Vessel 2 further defines an opening 53. A pressure conduit 54 is received in the opening 53 and communicates between the chamber 3 and the exterior of the vessel 2 for delivering gas from the chamber 3 to the exterior and vice versa.
Similarly, vessel 4 further defines an opening 55. A pressure conduit 56 communicates between the chamber 5 and the exterior of the vessel 4 for delivering gas from the chamber to the exterior and vice versa.
As shown in Figure 2, the hydraulic accumulators 58a and 58b have hydraulic fluid chambers 74 moveably received therein. The hydraulic accumulators 58a and 58b define chambers 106 and 108 respectively. Each of the pressure conduits 130 and 134 preferably communicate with the first chamber 106 of hydraulic accumulator 58a. Similarly, each of the pressure conduits 132 and communicate with the second chamber 108 of hydraulic accumulator 58b. The chambers 74 are connected to a diversionary valve 79 as shown in Figure 2, and the diversionary valve 79 is connected to a hydrostatic transmission or hydraulic gearmotor 80 connected to a generator or compressor. A valve 50 is located at the junction of conduits 130, 132, and 54 leading from vessel 2 and the hydraulic accumulators 58a and 58b for regulating gas flow. Similarly, valve 52 is located at the junction of conduits 136, 134, and 56 leading from vessel 4 and the hydraulic accumulators 58a and 58b for regulating gas flow. A valve 138 is located in the pressure conduit 134 between the vessel 4 and the hydraulic accumulator 58a for regulating gas flow. Similarly, valve 140 is located in the pressure conduit between vessel 2 and the hydraulic accumulator 58b.
Hydrostatic transmission 80 is preferably coupled to the diversionary valve 79. The transmission can be coupled to a flywheel and generator combination.
Vessel 2 is connected to the pressure conduit 54. Pressure conduit 54 feeds into pressure conduits 130 and 132. Valve 50 is located between conduit 54 and the Date Recue/Date Received 2020-08-31 conduits 130 and 132. Similarly, vessel 4 is connected to the pressure conduit 56.
Pressure conduit 56 feeds into pressure conduits 134 and 136. Valve 52 is located between conduit 56 and conduits 134 and 136. Valve 138 is located between conduit 134 and the hydraulic accumulator 58a leading to chamber 106.
Similarly, valve 140 is located between conduit 132 and hydraulic accumulator 58b leading to chamber 108.
In its operation, the apparatus reciprocates between a first valve position as shown in Figure 3 and a second valve position as shown in Figure 4 thereby driving the hydrostatic transmission. The reciprocal motion can be transformed into mechanical energy, which in turn can drive a generator or compressor for example.
The controller 70 controls the opening and closing of the valves of the plurality of co-operating valves. To begin the cycle whereby the apparatus moves to the first operating position, the controller opens valve 14 and closes valve 26 so that warm or hot thermal transfer fluid from the heat source 6 flows through thermal fluid conduit 42 to opening 31 and into the heat exchange conduit 10 of the vessel 2.
As the heated thermal transfer fluid flows through conduit 10 in the chamber 3, heat is transferred from the conduit to the surrounding gas in the chamber 3. This causes the pressure of the gas to increase. An acceptable pressure range of the gas for the purposes of the invention is approximately 150 psi to 5000 psi. The controller opens valve 16 and closes valve 24 so that the thermal transfer fluid can flow through the opening 33 through thermal fluid conduit 40 and back to the heat source 6 where the thermal transfer fluid is re-heated.
In addition to opening valve 14 and closing valve 26, the controller simultaneously opens valve 18 and closes valve 22 so that cool thermal transfer fluid from the heat sink 8 flows through conduit 44 to opening 35 and into heat exchange conduit 12 of vessel 4. As the cool thermal transfer fluid flows through the conduit 12 in the chamber 5, heat is transferred from the surrounding gas in the chamber 5 to the conduit. This causes the pressure of the gas to decrease. The controller opens valve 20 and closes valve 28 so that the thermal transfer fluid can Date Recue/Date Received 2020-08-31 flow through the opening 37. The thermal transfer fluid flows through thermal fluid conduit 38b and back to heat sink 8 where the fluid is re-cooled.
When maximum thermal transfer has occurred in the two vessels, the controller 70 will open the pressure valves 50 and 52. In valve position 1, Figure 3, the increased pressure in the vessel 2 will cause the gas from the chamber 3 to flow through the pressure conduit 54 to valve 50 and through conduit 130 to chamber 106 of the hydraulic accumulator 58a. At the same time, the decreased pressure in the vessel 4 will cause the gas from the second chamber 108 of the hydraulic accumulator 58b to flow through the pressure conduit 136 and into the chamber
5 of the vessel 4.
The movement of the hydraulic fluid 74 through the diversionary valve 79 drives hydrostatic transmission 80 and engages the generator or compressor.
When the fluid 74 from accumulator 58a has reached its maximum discharge, a sensor will cause the valves 110 and 112 to close.
In valve position 2 Figure 4, when valves 110 and 112 are closed, the controller will open valves 140 and 138 causing the working fluid 74 to move in the opposite direction forcing the gas from chamber 106 through conduit 134 and into chamber 5 of vessel 4. The cycle will repeat until the working fluid pressure in vessels 2 and 4 are at their minimum achievable differential.
During this multi-stroke operation, part of the mass of the working fluid contained in the vessels is re-distributed to the lower pressure or cooled vessel of the stage. This results in higher-pressure differentials than would normally be achieved if no mass transfer occurred. When the pressure achieves its minimum achievable differential in both vessels and no additional cycles can be obtained, the process will revert to the second stage. Pressure vessel 4 will then become the heated and therefore high-pressure source and vessel 2 will become the cooled and therefore low-pressure receiver of the working fluid.
The foregoing description represents a single operating module of an embodiment. In an embodiment, multiple pairs of vessels and hydraulic Date Recue/Date Received 2020-08-31 accumulators, which will comprise a module, may be used to attain a consistent output to the generator. In the embodiment, the modules are connected to a common driveshaft to develop higher rpms and torque to the transmission and to drive larger generators as required. The modules consisting of one pair of vessels and one assembly of hydraulic accumulators can be added as needed. They can also be of different capacities to deliver versatility to the installation, depending on the demand of the application.
In this multiple module embodiment, the valves controlling the cycles between each module in valve positions 1 and 2, can be operated by a synchronized camshaft or linear actuator.
In a second aspect, or part B 300, the output efficiency of the process described in part A is enhanced by using liquid nitrogen or liquid natural gas to cool the heat sink transfer fluid thereby allowing the system to use a heat source with a much lower ambient temperature while maintaining a similar temperature differential efficiency or Carnot efficiency between the heat source and the heat sink. The integrated thermal heat engine 200, comprised of heat engine 1 and the liquid nitrogen or LNG expansion engine 300, provides for a system that can synergistically operate with a greater overall efficiency than either component alone.
In addition, regardless of the heat source, the maximum realizable efficiency, or theoretical efficiency, will increase exponentially because of the increased temperature between the heat source and heat sink.
The second aspect, or part B, describes a novel expander engine to capture the energy of the conversion process of the liquid nitrogen or LNG to a gas as the liquid nitrogen or liquid natural gas absorbs heat from part A heat sink 8.
Whereas storing liquid nitrogen and capturing its expansion on its own is an established process, the current prevailing method of using a turbine to capture the expansion does not achieve acceptable round-trip conversion efficiency to attain economic viability.
Date Recue/Date Received 2020-08-31 Figure 5 illustrates a method of capturing the expansion of the liquid nitrogen or liquid natural gas and allowing it to:
First expand to a prescribed pressure in insulated pressure vessels and, Second, the pressurized nitrogen or liquid natural gas, which is now a gas, is released to a modified hydraulic accumulator assembly and process similar to the assembly described above for the heat engine and illustrated in more detail in Figures 2, 3, and 4. Alternately, the expanded gas can be stored in independent pressure vessels for release at a later time when demand is higher. This illustrates the versatility of the present invention over straight liquid nitrogen or liquid natural gas expansion through an expander/generator system.
In Figure 1, a vessel containing liquid nitrogen or liquid natural gas 170 provides a second, lower, heat sink for the heat engine 1. The liquid nitrogen or LNG
supply 170 reduces the temperature of the heat exchange fluid circulating through heat sink supply conduit 38a. The pump 171 maintains a sufficient flow rate to ensure the heat transfer fluid does not cool below its freezing point. As the heat transfer fluid passes through interchanger 190, it gives up enough heat to lower the temperature of the working fluid to its low temperature working limit but not the point at which it freezes. This provides the maximum temperature differential for thermal efficiency of the heat engine 1, while causing the liquid nitrogen, or LNG
contained in the supply 170 to expand through supply conduit 150 to the expansion engine 300.
Referring to Figure 5, the liquid nitrogen or LNG expansion engine 300 is illustrated in more detail. The nitrogen expansion engine 300 includes a separate hydraulic accumulator and hydraulic motor assembly. The nitrogen or LNG supply conduit 150 supplies manifold 152 which supplies insulated pressure vessels Date Recue/Date Received 2020-08-31 through control valves 153 in each of the vessels. Control valves 153 are of the type through which the rate of flow of the liquid nitrogen or LNG can be regulated.
The liquid nitrogen or LNG is then received by dispersion nozzles 154 in each of the pressure vessels, at which point the liquid nitrogen or LNG expands into gaseous form. The gaseous nitrogen or natural gas is allowed to expand to a prescribed pressure.
Heat source return conduit 40 is diverted through the pressure vessels 155 to add secondary heat to the gaseous nitrogen or natural gas thereby maintaining and increasing the pressure as prescribed for storage or immediate use through the expander and transmission/generator assembly 157. As will be appreciated from Figure 1, thermal fluid conducting heat return conduit 40 comprises the return path of the thermal fluid from the first vessel 2 and the second vessel 4.
Accordingly, after the heat flow from the heat source 6 has been used in the heat engine 1, it is directed to the expansion engine 300 to heat the expanded gas in the pressure vessels 155, and accordingly transfer further energy to the expanded gas. The thermal fluid may then be directed through the thermal fluid conducting heat return conduit 40 to return to the heat source 6 to be re-heated and supplied again to the heat engine 1.
In Figure 5, valves 160 are used to equalize the pressure between pressure vessels 155 as needed. Sensors 158 in each of the pressure vessels 155 communicate with the control module 70 to regulate the expander engine operation. Valves 159 control the release of the expanded gas to conduit 156 and thenceforth to the expander module 183.
In Figure 6, a hydraulic accumulator assembly is shown in position 1. The gaseous nitrogen or natural gas flowing from conduit 156 is received by distribution junction 177 and flows through conduit 176.
Valves 179 and 180 are open and valves 178 and 181 are closed, causing the gaseous nitrogen or natural gas flowing through conduit 176 to push the hydraulic Date Recue/Date Received 2020-08-31 fluid 183 in one direction which in turn forces the gaseous nitrogen or natural gas in chamber 184 to exit through valve 180.
During the operation of the expander engine in valve position 1, hydraulic motor 186 is caused to rotate, transferring the mechanical energy created by the conversion of the liquid nitrogen or LNG, to connecting driveshaft 187, which in turn will drive a generator, compressor, or hydraulic pump.
Similarly, in valve position 2, Figure 7, the gaseous nitrogen or natural gas flowing from conduit 156 is received by distribution junction 177 and flows through conduit 175. Valves 178 and 181 are open and valves 179 and 180 are closed, causing the gaseous nitrogen or natural gas flowing through conduit 175 to push the hydraulic fluid 183 in the opposite direction which in turn forces the gaseous nitrogen in chamber 185 to exit through valve 181.
During the operation of the expander engine in valve position 2, hydraulic motor 186 is caused to rotate, transferring the mechanical energy created by the conversion of the liquid nitrogen or LNG, to connecting driveshaft 187, which in turn drives the transmission and generator 186.
Multiple hydraulic assemblies are synchronized on a common driveshaft to enhance the steady delivery of power to the generator or compressor or a hydraulic pump, and facilitate the use of larger units.
In some aspects, the expander engine 300, may be selectively enabled so as to operate the heat engine 1 with the greater thermal differential during periods of low electricity demand when electricity prices are low.
The foregoing embodiments describe preferred embodiments only.
While various embodiments and particular applications of this invention have been shown and described, it is apparent to those skilled in the art that many other modifications and applications of this invention are possible without departing from the inventive concepts herein. It is, therefore, to be understood that within the scope of the appended claims, this invention may be practiced otherwise Date Recue/Date Received 2020-08-31 than as specifically described, and the invention is not to be restricted except by the scope of the claims.
Claims:
I/we hereby claim:
1. An apparatus for converting a differential in thermal energy temperatures between a heat source having a thermal conducting fluid and a heat sink having a cooling thermal conducting fluid, the apparatus comprising:
a heat engine comprising:
a pair of gas filled vessels in communication with said heat source and said heat sink;
a pressure driven reciprocating arrangement of hydraulic accumulators defining a first and second chamber separated by at least one hydraulic motor, said first chamber and said second chamber in fluid communication with said gas filled vessels;
said pair of gas filled vessels supplying a gas comprising a working fluid to said first chamber and second chamber of said pressure driven arrangement of reciprocating hydraulic accumulators; and, a controller for alternating flow of the thermal energy from heat source and heat sink between each of the pair of gas-filled vessels to alternately raise and lower pressure of said gas in the vessels to alternately transfer gas from one vessel to the first and second chamber of the hydraulic accumulator assembly and drive the assembly into reciprocating motion;
and, Date Recue/Date Received 2020-08-31
The movement of the hydraulic fluid 74 through the diversionary valve 79 drives hydrostatic transmission 80 and engages the generator or compressor.
When the fluid 74 from accumulator 58a has reached its maximum discharge, a sensor will cause the valves 110 and 112 to close.
In valve position 2 Figure 4, when valves 110 and 112 are closed, the controller will open valves 140 and 138 causing the working fluid 74 to move in the opposite direction forcing the gas from chamber 106 through conduit 134 and into chamber 5 of vessel 4. The cycle will repeat until the working fluid pressure in vessels 2 and 4 are at their minimum achievable differential.
During this multi-stroke operation, part of the mass of the working fluid contained in the vessels is re-distributed to the lower pressure or cooled vessel of the stage. This results in higher-pressure differentials than would normally be achieved if no mass transfer occurred. When the pressure achieves its minimum achievable differential in both vessels and no additional cycles can be obtained, the process will revert to the second stage. Pressure vessel 4 will then become the heated and therefore high-pressure source and vessel 2 will become the cooled and therefore low-pressure receiver of the working fluid.
The foregoing description represents a single operating module of an embodiment. In an embodiment, multiple pairs of vessels and hydraulic Date Recue/Date Received 2020-08-31 accumulators, which will comprise a module, may be used to attain a consistent output to the generator. In the embodiment, the modules are connected to a common driveshaft to develop higher rpms and torque to the transmission and to drive larger generators as required. The modules consisting of one pair of vessels and one assembly of hydraulic accumulators can be added as needed. They can also be of different capacities to deliver versatility to the installation, depending on the demand of the application.
In this multiple module embodiment, the valves controlling the cycles between each module in valve positions 1 and 2, can be operated by a synchronized camshaft or linear actuator.
In a second aspect, or part B 300, the output efficiency of the process described in part A is enhanced by using liquid nitrogen or liquid natural gas to cool the heat sink transfer fluid thereby allowing the system to use a heat source with a much lower ambient temperature while maintaining a similar temperature differential efficiency or Carnot efficiency between the heat source and the heat sink. The integrated thermal heat engine 200, comprised of heat engine 1 and the liquid nitrogen or LNG expansion engine 300, provides for a system that can synergistically operate with a greater overall efficiency than either component alone.
In addition, regardless of the heat source, the maximum realizable efficiency, or theoretical efficiency, will increase exponentially because of the increased temperature between the heat source and heat sink.
The second aspect, or part B, describes a novel expander engine to capture the energy of the conversion process of the liquid nitrogen or LNG to a gas as the liquid nitrogen or liquid natural gas absorbs heat from part A heat sink 8.
Whereas storing liquid nitrogen and capturing its expansion on its own is an established process, the current prevailing method of using a turbine to capture the expansion does not achieve acceptable round-trip conversion efficiency to attain economic viability.
Date Recue/Date Received 2020-08-31 Figure 5 illustrates a method of capturing the expansion of the liquid nitrogen or liquid natural gas and allowing it to:
First expand to a prescribed pressure in insulated pressure vessels and, Second, the pressurized nitrogen or liquid natural gas, which is now a gas, is released to a modified hydraulic accumulator assembly and process similar to the assembly described above for the heat engine and illustrated in more detail in Figures 2, 3, and 4. Alternately, the expanded gas can be stored in independent pressure vessels for release at a later time when demand is higher. This illustrates the versatility of the present invention over straight liquid nitrogen or liquid natural gas expansion through an expander/generator system.
In Figure 1, a vessel containing liquid nitrogen or liquid natural gas 170 provides a second, lower, heat sink for the heat engine 1. The liquid nitrogen or LNG
supply 170 reduces the temperature of the heat exchange fluid circulating through heat sink supply conduit 38a. The pump 171 maintains a sufficient flow rate to ensure the heat transfer fluid does not cool below its freezing point. As the heat transfer fluid passes through interchanger 190, it gives up enough heat to lower the temperature of the working fluid to its low temperature working limit but not the point at which it freezes. This provides the maximum temperature differential for thermal efficiency of the heat engine 1, while causing the liquid nitrogen, or LNG
contained in the supply 170 to expand through supply conduit 150 to the expansion engine 300.
Referring to Figure 5, the liquid nitrogen or LNG expansion engine 300 is illustrated in more detail. The nitrogen expansion engine 300 includes a separate hydraulic accumulator and hydraulic motor assembly. The nitrogen or LNG supply conduit 150 supplies manifold 152 which supplies insulated pressure vessels Date Recue/Date Received 2020-08-31 through control valves 153 in each of the vessels. Control valves 153 are of the type through which the rate of flow of the liquid nitrogen or LNG can be regulated.
The liquid nitrogen or LNG is then received by dispersion nozzles 154 in each of the pressure vessels, at which point the liquid nitrogen or LNG expands into gaseous form. The gaseous nitrogen or natural gas is allowed to expand to a prescribed pressure.
Heat source return conduit 40 is diverted through the pressure vessels 155 to add secondary heat to the gaseous nitrogen or natural gas thereby maintaining and increasing the pressure as prescribed for storage or immediate use through the expander and transmission/generator assembly 157. As will be appreciated from Figure 1, thermal fluid conducting heat return conduit 40 comprises the return path of the thermal fluid from the first vessel 2 and the second vessel 4.
Accordingly, after the heat flow from the heat source 6 has been used in the heat engine 1, it is directed to the expansion engine 300 to heat the expanded gas in the pressure vessels 155, and accordingly transfer further energy to the expanded gas. The thermal fluid may then be directed through the thermal fluid conducting heat return conduit 40 to return to the heat source 6 to be re-heated and supplied again to the heat engine 1.
In Figure 5, valves 160 are used to equalize the pressure between pressure vessels 155 as needed. Sensors 158 in each of the pressure vessels 155 communicate with the control module 70 to regulate the expander engine operation. Valves 159 control the release of the expanded gas to conduit 156 and thenceforth to the expander module 183.
In Figure 6, a hydraulic accumulator assembly is shown in position 1. The gaseous nitrogen or natural gas flowing from conduit 156 is received by distribution junction 177 and flows through conduit 176.
Valves 179 and 180 are open and valves 178 and 181 are closed, causing the gaseous nitrogen or natural gas flowing through conduit 176 to push the hydraulic Date Recue/Date Received 2020-08-31 fluid 183 in one direction which in turn forces the gaseous nitrogen or natural gas in chamber 184 to exit through valve 180.
During the operation of the expander engine in valve position 1, hydraulic motor 186 is caused to rotate, transferring the mechanical energy created by the conversion of the liquid nitrogen or LNG, to connecting driveshaft 187, which in turn will drive a generator, compressor, or hydraulic pump.
Similarly, in valve position 2, Figure 7, the gaseous nitrogen or natural gas flowing from conduit 156 is received by distribution junction 177 and flows through conduit 175. Valves 178 and 181 are open and valves 179 and 180 are closed, causing the gaseous nitrogen or natural gas flowing through conduit 175 to push the hydraulic fluid 183 in the opposite direction which in turn forces the gaseous nitrogen in chamber 185 to exit through valve 181.
During the operation of the expander engine in valve position 2, hydraulic motor 186 is caused to rotate, transferring the mechanical energy created by the conversion of the liquid nitrogen or LNG, to connecting driveshaft 187, which in turn drives the transmission and generator 186.
Multiple hydraulic assemblies are synchronized on a common driveshaft to enhance the steady delivery of power to the generator or compressor or a hydraulic pump, and facilitate the use of larger units.
In some aspects, the expander engine 300, may be selectively enabled so as to operate the heat engine 1 with the greater thermal differential during periods of low electricity demand when electricity prices are low.
The foregoing embodiments describe preferred embodiments only.
While various embodiments and particular applications of this invention have been shown and described, it is apparent to those skilled in the art that many other modifications and applications of this invention are possible without departing from the inventive concepts herein. It is, therefore, to be understood that within the scope of the appended claims, this invention may be practiced otherwise Date Recue/Date Received 2020-08-31 than as specifically described, and the invention is not to be restricted except by the scope of the claims.
Claims:
I/we hereby claim:
1. An apparatus for converting a differential in thermal energy temperatures between a heat source having a thermal conducting fluid and a heat sink having a cooling thermal conducting fluid, the apparatus comprising:
a heat engine comprising:
a pair of gas filled vessels in communication with said heat source and said heat sink;
a pressure driven reciprocating arrangement of hydraulic accumulators defining a first and second chamber separated by at least one hydraulic motor, said first chamber and said second chamber in fluid communication with said gas filled vessels;
said pair of gas filled vessels supplying a gas comprising a working fluid to said first chamber and second chamber of said pressure driven arrangement of reciprocating hydraulic accumulators; and, a controller for alternating flow of the thermal energy from heat source and heat sink between each of the pair of gas-filled vessels to alternately raise and lower pressure of said gas in the vessels to alternately transfer gas from one vessel to the first and second chamber of the hydraulic accumulator assembly and drive the assembly into reciprocating motion;
and, Date Recue/Date Received 2020-08-31
Claims (7)
Claims:
I/we hereby claim:
1. An apparatus for converting a differential in thermal energy temperatures between a heat source having a thermal conducting fluid and a heat sink having a cooling thermal conducting fluid, the apparatus comprising:
a heat engine comprising:
a pair of gas filled vessels in communication with said heat source and said heat sink;
a pressure driven reciprocating arrangement of hydraulic accumulators defining a first and second chamber separated by at least one hydraulic motor, said first chamber and said second chamber in fluid communication with said gas filled vessels;
said pair of gas filled vessels supplying a gas comprising a working fluid to said first chamber and second chamber of said pressure driven arrangement of reciprocating hydraulic accumulators; and, a controller for alternating flow of the thermal energy from heat source and heat sink between each of the pair of gas-filled vessels to alternately raise and lower pressure of said gas in the vessels to alternately transfer gas from one vessel to the first and second chamber of the hydraulic accumulator assembly and drive the assembly into reciprocating motion;
and, Date Recue/Date Received 2020-08-31 a liquid nitrogen or LNG expansion engine comprising:
a liquid nitrogen or LNG supply;
the liquid nitrogen or LNG supply in thermal communication with a cooling thermal transfer fluid circulating between the heat sink and the pair of gas filled vessels;
the liquid nitrogen or LNG supply further in fluid communication with and expansion engine;
wherein as the liquid nitrogen or LNG supply lowers the thermal energy of the thermal transfer fluid, liquid nitrogen or LNG is directed to the expansion engine.
a heat engine comprising:
a pair of gas filled vessels in communication with said heat source and said heat sink;
a pressure driven reciprocating arrangement of hydraulic accumulators defining a first and second chamber separated by at least one hydraulic motor, said first chamber and said second chamber in fluid communication with said gas filled vessels;
said pair of gas filled vessels supplying a gas comprising a working fluid to said first chamber and second chamber of said pressure driven arrangement of reciprocating hydraulic accumulators; and, a controller for alternating flow of the thermal energy from heat source and heat sink between each of the pair of gas-filled vessels to alternately raise and lower pressure of said gas in the vessels to alternately transfer gas from one vessel to the first and second chamber of the hydraulic accumulator assembly and drive the assembly into reciprocating motion;
and, Date Recue/Date Received 2020-08-31 a liquid nitrogen or LNG expansion engine comprising:
a liquid nitrogen or LNG supply;
the liquid nitrogen or LNG supply in thermal communication with a cooling thermal transfer fluid circulating between the heat sink and the pair of gas filled vessels;
the liquid nitrogen or LNG supply further in fluid communication with and expansion engine;
wherein as the liquid nitrogen or LNG supply lowers the thermal energy of the thermal transfer fluid, liquid nitrogen or LNG is directed to the expansion engine.
2. The apparatus of claim 1 wherein the liquid thermal expansion engine further comprises:
the expansion engine in thermal communication with a heating thermal expansion fluid circulating from the pair of gas-filled vessels back to the heat source;
wherein the heating thermal transfer fluid raises the thermal energy of the liquid nitrogen or LNG
the expansion engine in thermal communication with a heating thermal expansion fluid circulating from the pair of gas-filled vessels back to the heat source;
wherein the heating thermal transfer fluid raises the thermal energy of the liquid nitrogen or LNG
3. The apparatus of claim 2 wherein the heating thermal transfer fluid raises the thermal energy of the liquid nitrogen or LNG after it has been expanded into a gaseous state within a pressure vessel.
4. The apparatus of claim 1 wherein the expansion engine comprises at least one pressure vessel for receiving the liquid nitrogen or LNG and storing it in a gaseous state, and releasing the stored nitrogen or LNG as a second working fluid into a second pressure driven reciprocating hydraulic accumulator assembly comprising two hydraulic accumulators and at least one hydraulic motor.
5. An apparatus for converting liquid nitrogen or LNG to a gaseous state and harnessing the conversion to drive a hydraulic motor and generator or compressor, the apparatus comprising:
Date Recue/Date Received 2020-08-31 a means of delivering the liquid nitrogen or LNG under pressure to an expansion engine;
a means of delivering the liquid nitrogen or LNG from the interchanger to expansion valves and nozzles;
a means of injecting the liquid nitrogen or LNG as gaseous nitrogen or LNG into pressure vessels for storage;
a means for releasing the stored gaseous nitrogen or LNG to at least one hydraulic accumulator assembly to generate work.
Date Recue/Date Received 2020-08-31 a means of delivering the liquid nitrogen or LNG under pressure to an expansion engine;
a means of delivering the liquid nitrogen or LNG from the interchanger to expansion valves and nozzles;
a means of injecting the liquid nitrogen or LNG as gaseous nitrogen or LNG into pressure vessels for storage;
a means for releasing the stored gaseous nitrogen or LNG to at least one hydraulic accumulator assembly to generate work.
6. An apparatus of claim 5 further comprising a means or heating the gaseous nitrogen or LNG in the pressure vessels.
7. A method of converting thermal energy to mechanical/electrical energy that in the case of both engines described in Claim 1, can each be built in modules for scalability and connected via a common driveshaft according to the requirements of the site at which it is built and that synchronizes each module on the common driveshaft so that sequential timing of the cycling operation results in steady and consistent power transfer to the generator.
Date Recue/Date Received 2020-08-31
Date Recue/Date Received 2020-08-31
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA3091643A CA3091643A1 (en) | 2020-08-31 | 2020-08-31 | Dual output, compression cycle thermal energy conversion process |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA3091643A CA3091643A1 (en) | 2020-08-31 | 2020-08-31 | Dual output, compression cycle thermal energy conversion process |
Publications (1)
| Publication Number | Publication Date |
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| CA3091643A1 true CA3091643A1 (en) | 2022-02-28 |
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| CA3091643A Pending CA3091643A1 (en) | 2020-08-31 | 2020-08-31 | Dual output, compression cycle thermal energy conversion process |
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| CA (1) | CA3091643A1 (en) |
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2020
- 2020-08-31 CA CA3091643A patent/CA3091643A1/en active Pending
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