The invention is from the field of energy conversion. Specifically the invention is from the field of transforming thermal energy into kinetic energy.
Processes that transform external thermal energy contained in a process fluid into kinetic energy by using an external source of thermal energy to heat the process fluid are well-known and used.
These well-known processes use one single process fluid in one single cycle to extract physical work from external thermal energy. In most cases the process fluid used is water. The process fluid is heated by the external thermal energy above the evaporation temperature of the process fluid in order to have the process fluid change from the liquid phase to the gaseous phase. Pressurising the process fluid at low temperature before heating it requires a certain specific amount of kinetic energy. Heating the pressurised process fluid above its evaporation temperature causes a phase change from the liquid state to the gas state of the used process fluid. The phase change from liquid to gaseous state causes a significant increase of volume. In case of water the increase of volume is about 1,673 times. This increase in volume allows easily extracting kinetic energy from the expansion of the gaseous phase of the process fluid, which exceeds by far the amount of kinetic energy used at the beginning to pressurise the process fluid. After the expansion this process fluid is then condensed and, in most cases, recycled.
The most prominent of these processes is a process similar to the theoretical Rankin-cycle, which for simplicity will be referred to in this application as the ‘conventional single-medium-process’. All known ‘conventional single-medium-processes’ that are the present state of the art use only one single closed cycle process with only one single process fluid. All known ‘conventional single-medium-processes’ inherently have loss of the energy of the phase change in common.
As shown in
The overheated vapour of the used process fluid, e.g. steam, contains the energy transferred to it from the external source and streams to an expander (04). In the expander (04), which in most cases is a steam turbine, a part of the thermal energy in the process fluid is used to generate kinetic energy, indicated by arrow (08). The remaining expanded vapour or steam leaves the expander (04) and goes to the condenser (05). Condenser (05) is a heat exchanger in which the expanded gaseous process fluid is cooled and condensed to its liquid state by means of coolant from an external source that enters condenser (05) at (09) and exits at (10). After passing through condenser (05) liquid process fluid is returned to heat exchanger/boiler (02) through reservoir (07) by a pump (06).
During the evaporation of the process fluid in the heat exchanger/boiler (02) only a part of the introduced external thermal energy is changed into thermal energy that can then be used to generate kinetic energy. A large part of the introduced external thermal energy is needed for and consumed by the phase change of the process fluid from liquid to gas. This part of the energy that enables and sustains the phase change is referred to as “heat of evaporation” or “evaporation enthalpy” and in the past was also called “latent heat”. This large part of the energy consumed by the phase change from liquid to gas is not thermal energy and cannot be used in the expander.
Additionally, the temperatures in degrees Centigrade are shown in small tables attached to the specific parts of the process. Percentages of the energies relative to the introduced primary energy at the beginning at (01) are shown as numbers at each of the arrows indicting the parts through the ‘conventional single-medium-process’ using water as the process fluid. The energy numbers in kJ, as well the percentages are the amount of additionally introduced energy at (21) and do not contain the energy that may be already in the system or in the substances or media, when it operates above absolute zero degrees Kelvin.
The percentages in
The condenser (05) is a heat exchanger where the process fluid in the form of expanded steam meets a colder medium (09) that is used for the condensation. In most cases external ambient air or external nearby water are used as the second medium in the heat exchange of the condenser (05). The energy of the phase changes (27) is then transferred in most cases to the surrounding without any use inside the ‘conventional single-medium-process’.
In
If, in the exact same ‘conventional single-medium-process’ as shown and explained in
In the ‘conventional single-medium-process’ the steam leaves the expander before it is condensed. Therefore there is some thermal energy left in that part of the process. This is shown in
In case of the example with exactly the same ‘conventional single-medium-process’ but with 200° C. input, the expanded steam would leave the expander (04) as part of the process (25) at 120° Centigrade and thus with less than 32 kJ per kg steam. This thermal energy which has not been converted to ‘primary kinetic energy’ inside the expander (04) counts about 1.4% relative to the primary energy input at the beginning of the system of the ‘conventional single-medium-process’. Thus the possible conversion of primary energy to primary kinetic energy with the ‘conventional single-medium-process’ at 200° Centigrade cannot be more than 3.6% (three point six percent)! These numbers explain and present clearly why a ‘conventional single-medium-process’ is not suited for the utilisation of low temperature heat sources—the efficiency based on the fed external energy as primary energy would be incredibly low. Even if other numbers that are freely available for the energy content of steam at different temperatures are chosen as the base of such calculations, the results might be slightly different but would remain in the same range.
The ‘conventional single-medium-process’ and other existing and or known processes that extract kinetic energy from external thermal energy based on the changes of volume connected to the change of phase from liquid to gas and vice versa, exclusively consider thermal and kinetic energy. Accordingly these ‘conventional single-medium-processes’ are not designed to use or recover the energy of the phase change of the process fluid. Any additional use or recovery of the energy of the phase change of the process fluid is dependent on overcoming the following physical restrictions and/or limitations:
It is therefore a purpose of the present invention to provide a system and process for converting thermal into kinetic energy that overcomes the above-described physical restrictions and/or limitations to allow recovery of the energy of the phase change of the process fluid.
It is another purpose of the present invention to provide a system and process for converting thermal into kinetic energy that provides process efficiencies in all temperature ranges that are significantly higher than in any other processes known today.
Further purposes and advantages of this invention will appear as the description proceeds.
In a first aspect the invention is a complete process to transfer thermal energy into kinetic energy. The complete process comprises:
The following four processes are carried out simultaneously for each of the streams:
i) for a first work process stream:
In embodiments of the process the energy transfer process receives all of the freed energy of the condensation of the process fluid of the work process.
In embodiments of the process the energy transfer process transfers all of the freed energy of the condensation of the process fluid of the work process back into the work process.
In embodiments of the process the first work process stream and the second work process stream share the same valve mechanism and pass through the valve mechanism to the expansion chamber of the expander together.
In embodiments of the process at least one additional heat exchanger further cools the energy transfer process fluid after the energy transfer fluid passes through the first heat exchanger by transferring thermal energy from the energy transfer process fluid to at least one process fluid flowing in at least one process external to the work process and energy transfer process of the complete process.
In embodiments of the process at least one additional expander decreases further the remaining pressure of the energy transfer process fluid after the energy transfer fluid passes through the first heat exchanger thus transforming at least a part of the pressure into available kinetic energy at the mechanical outlet of the expander.
In a second aspect the invention is a system for carrying out the complete process of the first aspect for transferring thermal energy into kinetic energy. The system comprises the following components:
In embodiments of the system at least one additional heat exchanger further cools the energy transfer process fluid after the energy transfer fluid passes through the first heat exchanger by transferring thermal energy from the energy transfer process fluid to at least one process fluid that flows in at least one process external to the work process and energy transfer process of the complete process.
Embodiments of the system comprise at least one additional heat exchanger in the energy transfer stream, that is configured to further cool the energy transfer process fluid after the energy transfer fluid passes through the first heat exchanger by transferring thermal energy from the energy transfer process fluid to at least one process fluid carrying thermal energy from an external energy source that flows into a heat exchanger connected before the second heat exchanger thus increasing the temperature of the at least one process fluid carrying thermal energy from the external energy source before it reaches the second heat exchanger.
Embodiments of the system comprise at least one additional expander in the energy transfer stream that is configured to decrease the pressure of the energy transfer process fluid after the energy transfer fluid passes through the first heat exchanger thus transforming at least a part of the pressure into available kinetic energy at the mechanical outlet of the expander.
In embodiments of the system the first work process stream and the second work process stream share the same valve mechanism and pass through the valve mechanism to the expansion chamber of the expander together.
In embodiments of the system the valve mechanism before the expander is configured to operate in a clocked fashion to prevent premature evaporation of the work process fluid before it enters the expander.
In embodiments of the system the valve mechanism before the expander is configured as a lock mechanism to prevent premature evaporation of the work process fluid before it enters the expander.
In embodiments of the system the valve mechanism before the expander is configured as a metering mechanism to prevent premature evaporation of the work process fluid before it enters the expander and to allow exactly metered amounts of the work process fluid to be released into the expansion chamber.
In embodiments of the system the metering mechanism is a metering rotating valve mechanism.
In embodiments of the system at least one of the pumps or the compressor are connected to the expander either by a direct or indirect mechanical, hydraulic, pneumatic, or electrical connection in a way that at least a part of the kinetic energy provided by a mechanical outlet of the expander at least partly provides the necessary kinetic energy for operation of the at least one of the pumps or compressors.
In embodiments of the system at least one of the pumps or the compressor of the system is connected to an additional expander in the energy transfer stream either by a direct or indirect mechanical, hydraulic, pneumatic, or electrical connection in a way that at least a part of the kinetic energy provided by a mechanical outlet at least partly provides at least some of the necessary kinetic energy for operation of the at least one of the pumps or compressors.
In embodiments of the system the speed of the work process and the energy transfer process can be adjusted relative to each other, with a different relative speed of the pumps of the work process compared to the compressor of the energy transfer process.
In embodiments of the system the cross section of the components through which the process fluids are moving are configured in such a way that the flow speeds and flow pattern of the process fluids at specific locations at which thermal energy in the process fluids is either increased or decreased, thereby changing the temperature of the process fluids, are optimised and thus energy losses reduced.
All the above and other characteristics and advantages of the invention will be further understood through the following illustrative and non-limitative description of embodiments thereof, with reference to the appended drawings.
The present invention combines interacting main processes and sub-processes to extract kinetic energy from thermal energy. These different interacting processes and sub-processes are physically separate from each other with the main processes operating as closed cycles that operate with two different process fluids parallel to each other and interact with each other, in order to consider and utilize sufficiently all three forms of energy, i.e. thermal energy, kinetic energy, and the energy of the phase changes. By interacting, these different main processes and sub-processes enable a ‘combined-process’ that especially allows the highly efficient transformation of low temperature thermal energy into kinetic energy. Unique and outstanding features of the combined process of the invention are an artificial heat sink, the recovery and conservation of the condensation enthalpy in one of the sub-processes, and keeping all thermal energy inside the combined process. With the combined process even sub-zero temperatures can be used with high efficiency as heat sources. Additionally, the independence of the overall efficiency of transforming thermal energy into kinetic energy from the operating temperatures is significantly increased. For energy conservation and the environment the advantages of this invention are great.
In its minimal form that ensures that it can work orderly the process of the invention is comprised of two main processes that define separate streams for transferring energy that both operate as closed cycles parallel to each other. All processes together are referred to as the ‘complete process’. The following description and figures show for each component, part, process, or sub-process only the required minimum number that can allow orderly operation of the system.
It is always possible to increase the number of functional components, or streams and let those work in parallel in a similar way that, for example, in a piston engine several cylinders, pistons, or the number of valves or spark plugs per cylinder could be increased; all nevertheless still operating under the same principle, which would be described only with the minimum number of each item necessary for complete functionality.
In the embodiment shown in
In heat exchanger (43) the pressurised, liquid, cold work stream process fluid is pressed forward by pump (42) and is heated up by the gaseous hot process fluid of the parallel operating energy transfer process (120) that will be described herein below. Heat exchanger (43) transfers thermal energy into the work stream process fluid from the energy transfer stream process fluid that enters heat exchanger (43) in the most efficient form from the opposite side. To this end the energy transfer stream process fluid was heated up and the liquid work stream process fluid has at its entrance to heat exchanger (43) still its coldest temperature in the first work stream.
In nearly all but some extreme cases the first of the two parallel work streams is heated to a much higher temperature than the second of the two parallel work streams. The pressure applied by pump (42) prevents this specific part of the work stream process fluid from starting to evaporate after being heated in heat exchanger (43). The energy that is transferred in heat exchanger (43) from the energy transfer stream process fluid into the work stream process fluid corresponds to the energy that is transferred during the condensation process into the energy transfer stream process fluid.
The work stream process fluid has the highest temperature it can reach in the first work stream (150) at this point when leaving heat-exchanger (43) before entering the valve mechanism (45).
The valve mechanism (45) has the main task of preventing the overheated, pressurised work stream process fluid from evaporation before it is inside the expansion-chamber (46) of the expander. The valve mechanism (45) also controls the flow-speed of the work stream process fluid in order to prevent a part of the hot work stream process fluid to increase speed and prematurely start evaporating. An advantageous way to realise controlling valve (45) is by using it as a lock system that disrupts fluid communication between the amount of work stream process fluid that is entering the expansion chamber (46) of the expander and the work stream process fluid that is still before valve mechanism (45). Another advantageous embodiment of the valve mechanism (45) is a metering mechanism, e.g. a rotating valve mechanism. If valve mechanism (45) causes a clocked or pulsed performance this would not pose any disadvantage for the process. For orderly operation the valve mechanism (45) and pump (42) need to be adjusted to or harmonised with each other.
When the overheated, pressurised work stream process fluid passes through the valve mechanism (45) and enters the expansion chamber (46) it immediately flash evaporates due to the increased cross section of the expansion chamber (46). The expander can be any kind of expander that either works with positive replacement or a fluid mechanical mechanism to generate a movement from the pressure difference of the flash work stream process fluid at the entrance and the exit of the expansion chamber (46). An advantageous embodiment of the expansion chamber is an engine that operates with positive replacement and can handle condensation and the formation of drops inside the expansion chamber. It is also possible to use a pre-chamber for the flash-evaporation as is known from turbines that work with super-critical steam. For the complete-process (100) the design of the expansion chamber (46) is not important.
During the flash evaporation in the expansion chamber (46) the overheated, pressurised work stream process fluid of both parallel work streams of the work process (110) consumes a specific amount of thermal energy to enable the phase change from the liquid state to the gaseous state and the temperature of the work stream process fluid drops to a lower temperature. In most cases this energy consumed for the phase change will be the largest part of the thermal energy contained in the work stream process fluid. The remaining thermal energy of the now gaseous work stream process fluid applies a certain pressure in the expansion chamber that is then converted to kinetic energy. In
When the work stream process fluid is expanding, thus converting thermal energy into kinetic energy, and has reached the furthest point in expansion chamber (46), an outlet mechanism (48) connects the now expanded gaseous work stream process fluid to the following condenser (49). The outlet mechanism from the expansion chamber (48) to the condenser (49) can be an opening, a special valve or an outlet mechanism as described in patent application WO/2013072913 A1 to the inventor of the present invention.
The condenser (49) works as a heat exchanger. One medium is the work stream process fluid that circulates in the closed work process (110). The other medium going through heat exchanger (49) is the gas of the other closed main process, i.e. the energy transfer process (120). When entering heat exchanger (49) the gas of the energy transfer process (120) is significantly colder than the work stream process fluid.
The main task of the heat-exchanger (49) is to transfer energy from the expanded work stream process fluid to the energy transfer stream process fluid so that the work stream process fluid condenses and turns into its liquid state. The energy that has to be removed from the work stream process fluid to bring about the complete condensation of the work stream process fluid leads to a decrease of temperature of the work stream process fluid and an increase of temperature of the energy transfer stream process fluid.
The cooled, liquid unpressurised work stream process fluid flows then from the condenser (49) to the reservoir (41) and the same cycle for the first work stream (150) is repeated.
As can be seen in
The work stream process fluid of the second work stream (140) is heated without evaporating in heat exchanger (53) and released through a special valve mechanism (45) into the expansion chamber (46) of the expander. The work stream process fluid of the second work stream (140) flash evaporates only in the expansion chamber (46). In the embodiment shown in
Both, the first work stream and the second work stream move separated and parallel to each other until each stream has passed through its first heat exchanger. For the first work stream this is heat exchanger (43) for the second work stream this is heat exchanger (53). After they have each passed their respective first heat exchanger, both streams can be merged into one stream at any given point until the work stream process fluid flash evaporates and changes from the liquid phase into the gas phase inside the expansion chamber (46). It is technically advantageous if both partial streams of the work-stream meet before the valve mechanism (45) because then only one single valve mechanism is required. Otherwise this does not change the complete process (100) and/or the work process (110).
By splitting the work stream (110) into two parallel partial streams, it is possible to heat them independently and parallel to each other. The first work stream (150) receives the energy of the condensation of the work stream process fluid and thus keeps this energy inside the complete process (100). For the energy balance of the complete process (100) and for its efficiency this is of great importance. The second work stream (140) receives the external thermal energy that is introduced into the system from outside. By transferring the energy in parallel and not sequential or successively, both the first and second work processes can receive the complete amount of energy that is supposed to be transferred to each of them. Both parallel partial streams have at the beginning of the transfer of energy their lowest temperature in the work process (110) and the complete process (100), thus providing the ability to use the maximum temperature difference for the transfer of thermal energy.
Because the evaporation is not supposed to happen before either of the first or second work streams have reached the expansion chamber (46), it is possible that either one or both of them reach a temperature where the work stream process fluid is in a super-critical state. This has no process changing influence, neither on the task of the work process nor on the complete process.
Both parallel work streams mix with each other after they have received energy respectively in the heat exchangers (43) and (53). This mixing of both parallel work streams will lead to an average temperature that is lower than the temperature of the stream that had the higher temperature. However, this does not lead to a loss of energy because the combined streams still contain the exact same amount of energy (e.g. in kilo Joule) as the sum of the two parallel partial streams.
The energy transfer stream uses a gas, e.g. carbon-dioxide and methane, as a medium referred to as the “energy transfer stream process fluid”. The main task out of several tasks of the energy transfer stream is to keep the energy which is extracted during condensation of the work stream process fluid inside the complete process. To this end the energy transfer stream process fluid streams into heat exchanger (49) with the coldest temperature the energy transfer stream process fluid has during the energy transfer process. In heat exchanger (49) thermal energy plus the energy related to the condensation is transferred from the nearly completely expanded work stream process fluid in its gaseous state with a temperature close to its condensation temperature into the energy transfer stream process fluid that has at the entrance of heat exchanger (49) its lowest temperature and its lowest pressure within the energy transfer stream. The energy transfer stream process fluid thus increases its temperature inside heat-exchanger (49) by the energy extracted from the work stream process fluid that is the second stream in heat-exchanger (49) and in turn the work stream process fluid condenses as a result of the extraction of energy.
When the energy transfer stream process fluid is extracting energy from the condensation of the work stream process fluid in heat exchanger (49) the energy related to the condensation of the work stream process fluid is transferred to the energy transfer stream process fluid at a low temperature level compared to the temperatures at other points of the complete process. The amount of the energy transfer stream process fluid has to be chosen accordingly to be able to absorb this energy in the form of thermal energy. The most advantageous amount of the energy transfer stream process fluid in the energy transfer stream is therefore determined by the ability to absorb the total energy freed during the condensation of the work stream process fluid. The energy that needs to be absorbed expressed in kilo Joule divided by the possible temperature increase in degrees Kelvin by the following compression in compressor (72), the heat capacity of the specific energy transfer stream process fluid at the different chosen temperatures, and relative flow speed of the energy transfer stream process fluid compared to the flow speed of the work stream process fluid gives the minimum mass and thus the minimum amount of gas that is needed for the energy transfer stream in order to be able to extract all of the energy related to the condensation from the work-stream. Several sample calculations herein below will explain this in more details.
Heat-exchanger (49) is followed in the energy transfer stream by compressor (72). The heated energy transfer stream process fluid is sucked into and compressed by compressor (72) to higher pressure and higher temperature.
Compressing the energy transfer stream process fluid in compressor (72) to a specific higher temperature allows then, in a following step, the transfer of this energy from the condensation back through heat exchanger (43) into the work stream process fluid in the first work stream (150). The thermal energy transferred from the energy transfer stream process fluid to the first work stream at heat exchanger (43) is used in the work stream (110) to support the evaporation of the complete work stream process fluid not just the process fluid of the first work stream. According to the amount of energy that needs to be transferred, the temperature of the energy transfer stream process fluid after compressor (72) needs to be sufficiently high enough to enable the transfer of a sufficient amount of thermal energy into the work stream process fluid of the first work stream (150). The exact temperature increase that the energy transfer stream process fluid needs to reach in compressor (72) is given by the amount of energy that needs to be transferred in kilo Joule, divided by the mass per time and the specific heat capacity of the energy transfer stream process fluid and the relative flow speed of the energy transfer stream process fluid compared with the flow speed of the work stream process fluid.
This step of elevating the energy of the condensation extracted from the work stream process fluid to a higher temperature level by compressing the energy transfer stream process fluid is only possible in a separate process and also only with a different process fluid than those of the work stream.
Leaving compressor (72) the pressurised and hot energy transfer stream process fluid enters the heat-exchanger (43). After the compression the energy transfer stream process fluid has at this location its highest temperature in the energy transfer stream. Inside heat exchanger (43) the pressurised and hot energy transfer stream process fluid exchanges thermal energy with the pressurised liquid work stream process fluid which enters heat exchanger (43) at its coldest temperature in the first work stream. Both the work stream process fluid and the energy transfer stream process fluid exchange thermal energy, thereby increasing the temperature of the work stream process fluid and lowering accordingly the temperature of the energy transfer stream process fluid.
The now cooler energy transfer stream process fluid leaves heat exchanger (43) and streams either directly to heat exchanger (49) or in other embodiments through one or several additional heat exchangers or through one or several additional expanders.
In case that instead of an oxidiser or fuel gas for a burner another medium is used as source of external thermal energy, especially a source with relative low temperature, thermal energy can be transferred from the additional heat exchanger (83) to an optional additional heat exchanger (86) in the incoming stream of external energy (see
In other embodiments the now cooler energy transfer stream process fluid leaves heat exchanger (43) and streams through at least one additional expander (85), where at least part of the remaining energy in form of the remaining pressure of the pressurised energy transfer stream process fluid is converted to kinetic energy at the mechanical outlet of the expander that can be used, e.g. in the complete process (100) or parts of it, e.g. compressor (72).
In other embodiments at least one additional heat exchanger (83) and together at least one additional expander (85) are used in at least one of the energy transfer stream processes.
Cooling the energy transfer stream process fluid also decreases its pressure. It is therefore advantageous to increase and/or decrease accordingly the cross sections of the paths, for example pipes, in the system followed by the energy transfer stream process fluid in order to keep pressure losses at a minimum. After the energy transfer stream process fluid has passed through heat exchanger (43) (and optionally) additional heat exchangers (83), (84), and/or expander (85), or additional expanders, the energy transfer stream process fluid arrives at the entrance of heat exchanger (49). At the entrance of heat exchanger (49) the energy transfer stream process fluid is going through a decompression. By increasing the cross section of the path ((117), (127), and 137) in
Through the suction that comes from the compressor (72) located in the heat transfer stream (120) right after the heat exchanger (49) the energy transfer stream process fluid is moved through heat exchanger (49) and does therefore not require a remaining pressure to overcome the streaming resistance inside heat exchanger (49). The rapid cooling to a very low temperature constitutes an artificial heat sink in the complete process (100). As opposed to prior art systems, especially those based on the ‘conventional single-medium-process’ in use since the year 1784 until today, utilize the surroundings, i.e. either the air or some water-body, as the point with the lowest temperature the present invention has its own controllable heat sink as an integral part of the complete process.
Like in other cryo-aggregates or cooling devices, the temperature of the heat sink can be chosen to be significantly below ambient temperature, thus creating a temperature difference between the ambient temperature and the lowest temperature within the complete process that can even be used to generate kinetic energy from a source of external thermal energy with ambient temperature of the surroundings. This is even possible if the surrounding ambient temperature is a sub-zero temperature. For such applications both process fluids have to be chosen with the right boiling temperature and the complete process/system needs to be realised with sufficient thermal insulation. Sample calculations herein below show such an example.
In cases where the external energy that is introduced into the complete process raises the temperature of the second work stream (140) significantly higher at heat exchanger (53) than the temperature that the first work stream (150) reaches after heat exchanger (43) it would be possible to let the first work stream and the second work stream meet directly at heat exchanger (53). Then the already heated first work stream would be further heated directly by the external energy at heat exchanger (53). The same result could also be achieved by dividing heat exchanger (53) into two regions where the higher temperature region is used by the first work stream (150) and the lower temperature region is used by the second work stream (140). However, from an energetic point of view it makes no difference where the energy is transferred or whether the energy is transferred into the complete process (100) through the first or the second work stream or through both. At the end both streams will eventually mix, either right after the heat exchangers (53) and (43) or at the latest inside expansion chamber (46). Then the two parallel streams of the work stream process fluid will mix together and thus reach a balance between the different temperature levels of thermal energy. What counts for the efficiency of the complete process is how much energy is introduced into the expansion chamber (46), the different temperatures of the two parallel work streams, however, are not important. The simplest solution, which is shown in
It could also be advantageous to mechanically connect the expansion chamber (46) with at least one of the pumps (42), (51) and compressor (72) in order to utilize part of the energy output from the expander to operate these components. Additionally the pumps and compressors could be driven by electro-motors receiving their energy from a generator that is connected to the expander; this would also allow operating the different pumps and the compressor at different rotational speeds. The optional additional expander (85) (see
The external energy can be introduced into the system in many ways, not unlike can be done with existing systems today. The external thermal energy can be generated in a burner through any kind of combustion, it can be introduced through a medium with thermal external energy that transfers its thermal energy through heat exchanger (53) into the work stream process fluid, it can be solar generated thermal energy, it can be heat-radiation, or any other kind of radiation able to introduce energy that does not even need to be thermal energy into the process or system or any other method to introduce thermal energy into heat exchanger (53). For the function of the complete process of this invention itself, the way how the external thermal energy is introduced from outside is not important.
Comparing the ‘conventional single-medium-processes’ with this invention based on the relevant calculations of the different energy streams involved, in the form of several simple small tables revealing temperatures and energies at various locations in the system, makes the innovative step, the purpose, and the technological benefit of this invention very clear and easy to understand.
The different energies in
In
In
The only part of the introduced external energy, referred to as primary energy (21) that can be changed into kinetic energy in the ‘conventional single-medium-process’ is the part that is shown at (24). It cannot reach more than 42% of the energy put into the system of the ‘conventional single-medium-process’. This energy is herein in
At heat exchanger (49) the condensation is started by extracting thermal energy (114). In contrast to the ‘conventional single-medium-process’ in which the condensation of the medium is done using an external source of coolant, in the present invention condensation of the work stream process fluid is done with the energy transfer stream process fluid. By transferring the energy of the condensation into the energy transfer process (120) the energy of the condensation, shown at (115), can be kept in the complete system. Because this energy is not useful for the process on such a low temperature level, compressor (72) elevates the temperature, shown at (116), so it can be used in heat exchanger (43). The tables (115) and (116) show the difference in temperature. In both tables the temperature is also shown in degrees Kelvin. This is relevant because the temperature from the stream before compressor (72) and afterwards (116) needs to be increased in the example of
The compressed energy transfer stream process fluid is at a sufficient high temperature level (116) after the compression at compressor (72) to transfer all the energy that was recovered from the condensation in heat exchanger (49) to the first work stream (150) through heat exchanger (43). The energy that is needed for compressor (72) has to be taken from the primary kinetic energy at (113). Also the energy needed for the pumps (42) and (51) needs to be taken from the primary energy at (113). It is therefore an advantageous embodiment to connect the compressor and/or one or both pumps with the energy output of expander (47). This connection can be in form of a mechanical connection, like a common shaft, also other ways of connection are possible, like hydraulic, pneumatic, or electrical, etc.
Another advantage of the present invention over the prior art, besides recovering the energy of the phase change, is the lower temperature that allows more energy to be extracted at heat exchanger (53) from the external energy source. In the ‘conventional single-medium-process’ the process medium, usually water, is condensed at ambient temperature of the medium, e.g. an air or a water body, outside the system. Therefore the temperature of the process fluid in the ‘conventional single-medium-process’ streaming in
As can be seen in
The additional energy fed by the first stream shown at (128) is the recovered energy of the condensation (125) after heat exchanger (49). The energy for the compressor (72) and the pumps (42) and (51) has to be subtracted from the primary kinetic energy (123).
The temperature difference of the energy transfer stream process fluid before the compressor (72) shown at (125) and after it shown at (126) can be seen as 436° Centigrade or as a 2.17 times increase of absolute temperature. This is much lower than in a conventional Diesel engine in respect of pressure and temperature.
A more extreme example is shown in
The process fluid of the work stream in this specific case needs to have a boiling point at or below minus 40° Centigrade. In this extreme example of
At heat exchanger (53) the external energy is transferred to a much colder second work stream (140) with a temperature of minus 40° Centigrade. This leads than to a temperature of the second work stream of minus 10° Centigrade, shown at (131). The first work stream (150) comes with a temperature of plus 112.3° Centigrade out of heat exchanger (43), shown at (138). Both parallel work streams mix and enter the expander (46) with a temperature of plus 51.2° Centigrade (132). The work stream process fluid flash evaporates in expander (46). By evaporating most of the thermal energy is consumed by the phase change from the liquid phase to the gaseous state. The amount of energy that is delivered by the first work stream has at best the temperature and thus the thermal energy that corresponds with the amount of energy needed for the phase change. When the work stream process fluid evaporates and expands inside the expander (46) it converts a certain amount of thermal energy into primary kinetic energy (133). With its remaining thermal energy the gaseous work stream process fluid leaves the expander (46) expanded and colder than it entered at a temperature of minus 36° Centigrade (134). There the colder and expanded gaseous work stream process fluid condenses and heat exchanger (49) transfers the energy of the condensation plus the remaining thermal energy to the energy transfer stream process fluid, which in this case is a gas with a sufficiently low boiling point, for example carbon-dioxide or methane.
In
Such a system needs good thermal insulation in order to keep heat losses small. The amount of energy from the low external temperature thermal energy that is available to be converted to kinetic energy is in this process at 80% very high. Thermal and mechanical losses need to be subtracted. Because the amount of energy per kilogram is at this temperature range rather small, the losses of the compressors, pumps, and the expander are relative to the primary energy higher than they would be at higher temperature ranges.
The calculations made in the three examples in
As can be understood from the description and the calculations the main advantages of keeping the significant amount of energy of the phase change within the system are only made possible:
Although embodiments of the invention have been described by way of illustration, it will be understood that the invention may be carried out with many variations, modifications, and adaptations, without exceeding the scope of the claims.
Number | Date | Country | Kind |
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254492 | Sep 2017 | IL | national |
Filing Document | Filing Date | Country | Kind |
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PCT/IL18/50917 | 8/20/2018 | WO | 00 |