Bland/Ewing Cycle Improvements

Abstract

The present application relates to systems and methods for applying open cycle and closed cycle valved cell heat engines to Bland/Ewing (B/E) chemo-thermodynamic cycles. The application proposes several new embodiments of a closed cycle valved cell (CCVC) heat engine, including means to create a fully-regenerated isochorically-heated CCVC heat engine. The application further relates to the application of such a heat engine to B/E chemo-thermodynamic half-cycles.

Claims

1. Systems and methods for applying open cycle and closed cycle valved cell heat engines to Bland/Ewing chemo-thermodynamic cycles as described herein.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0129] The invention will be illustrated in greater detail by description in connection with specific examples of the practice of it and by reference to the accompanying drawings, in which:

[0130] FIG. 1 is partially cutaway and partially transparent solid model of the existing EISG CCVC testbed. FIG. 1 shows the EISG CCVC testbed at Top Dead Center (TDC). The numbers under the boxed labels represent information found within corresponding boxed labels within FIG. 3

[0131] FIG. 2 is similar to FIG. 1 and shows the EISG CCVC testbed at Bottom Dead Center (BDC).

[0132] FIG. 3 is a schematic of the processes that occur within the EISG CCVC testbed. The numbers under the boxed labels represent the various means employed with the EISG CCVC testbed. The prime mover can be seen as the standard crankcase and single-cycle camshaft below the engine in FIG. 1, FIG. 2, and elsewhere in other figures.

[0133] FIG. 4 is a proposed modified version of the EISG CCVC testbed. FIG. 4 shows the EISG CCVC testbed at Top Dead Center (TDC). The numbers under the boxed labels represent additional information found within corresponding boxed labels within FIG. 6 and FIG. 7.

[0134] FIG. 5 is similar to FIG. 4 and shows the modified EISG CCVC testbed at Bottom Dead Center (BDC).

[0135] FIG. 6 is a schematic of the processes that occur within a modified version of the EISG CCVC testbed. The numbers under the boxed labels represent the various means employed within a modified version of the EISG CCVC testbed.

[0136] FIG. 7 is a schematic of the processes that occur within another modified version of the EISG CCVC testbed. The numbers under the boxed labels represent the various means employed within another modified version of the EISG CCVC testbed.

[0137] FIG. 8 is another proposed modified version of the EISG CCVC testbed. FIG. 8 shows the EISG CCVC testbed at Top Dead Center (TDC). The numbers under the boxed labels represent additional information found within corresponding boxed labels within FIG. 12, FIG. 13, and FIG. 14.

[0138] FIG. 9 is a rotated closeup of the modified EISG CCVC testbed shown in FIG. 8.

[0139] FIG. 10 is similar to FIG. 8 and shows the modified EISG CCVC testbed at Bottom Dead Center (BDC).

[0140] FIG. 11 is a rotated closeup of the modified EISG CCVC testbed shown in FIG. 10.

[0141] FIG. 12 is a schematic of the processes that occur within another modified version of the EISG CCVC testbed. The numbers under the boxed labels represent the various means employed within a modified version of the EISG CCVC testbed.

[0142] FIG. 13 is a schematic of the processes that occur within another modified version of the EISG CCVC testbed. The numbers under the boxed labels represent the various means employed within a modified version of the EISG CCVC testbed.

[0143] FIG. 14 is a schematic of the processes that occur within another modified version of the EISG CCVC testbed. The numbers under the boxed labels represent the various means employed within a modified version of the EISG CCVC testbed.

DETAILED DESCRIPTIONS

Description-First Embodiment

[0144] This is a description of the unmodified EISG CCVC testbed, aka hybrid Ericsson/Stirling closed cycle heat engine. For reference, see paragraph 12 and 13 above and FIG. 1, FIG. 2, and FIG. 3 of the drawings.

[0145] The EISG CCVC testbed was designed to be a closed system with a sealed and pre-pressurized working fluid, similar to the standard sealed and pre-pressurized working fluid for Stirling engines. In the EISG CCVC testbed test cases, nitrogen (N2) was used as the working fluid. Pre-pressurization of the testbed was held to about 90 psi, with peak measured pressure of about 190 psi. Peak temperature was about 511 K. Heat energy was supplied by an electric coil heater and an electric cartridge heater physically in contact with the heater heat exchanger. Cooling was supplied by water flowed through coils of copper tubing exterior to and interior to the cooler heat exchanger and exterior to the walls of displacer #1 and the combination displacer #3/compressor.

[0146] The piston is a single contiguous, hollow aluminum 2 diameter tubular piston rod with a 2.5 diameter pancake piston on either end. The piston is cyclically driven through a 2.75 stroke by a prime mover below the engine proper. A diameter titanium rod connects the bottom of the contiguous piston to the prime mover. A 2.5 outer diameter teflon-and-stainless spring steel seal is mounted in each of the 2.5 diameter pancake pistons, and a single 2 inner diameter teflon-and-stainless steel spring seal is mounted in a 2 diameter tube between displacer cylinder #1 and the displacer cylinder #2. The teflon seals are not lubricated and ride on a vapor-deposited nickel substrate that is coating the single 2 diameter piston connecting rod and the two 2.5 diameter cylinders. Excluding manifold and heat exchanger spaces, the four internal spaces of the engine are comprised of the two 2.5 diameter pancake pistons with piston seals, the 2 diameter connecting rod, the 2 diameter cylinder with 2 diameter rod seal, the two 2.5 diameter cylinders, and the diameter connecting rod, thus forming the 13.5 cubic inch expander space, the 13.2 cubic inch displacer #3/compressor space, and the 4.86 cubic inch #1 and #2 displacer spaces. The piston is driven by the single converted crankshaft with a 2.75 throw from a converted single-cylinder four-stroke gasoline prime mover with an oil-lubricated crankcase. The crankshaft is contiguous with a modified single-lobe camshaft, which pushes a cam follower and connecting rod to operate a rocker arm mounted on the expander cylinder head, which opens and closes the poppet-type exhaust valve. The exhaust valve is spring-biased towards closed and opens at or just prior to the upstroke engine's upstroke at BDC and closes just prior to the downstroke at TDC. An arm mounted just below a teflon-and-stainless steel spring seal exhaust valve stem seal extends perpendicularly from the exhaust valve stem. The exhaust valve stem-mounted arm is used to (A) physically close the transfer valve and (B) compress the transfer valve opening spring when the exhaust valve closes as BDC is approached. The reverse poppet-type transfer valve stem has an o-ring seal. The transfer valve stem and and o-ring seal are oil-cooled and oil-lubricated with lower pressure oil, as is the exhaust valve stem. The upper portion of the transfer valve head is designed to seal against an upper seat and thus physically protect the transfer valve stem o-ring seal during the passage of the higher pressure hot gases flowing past the transfer valve head and into the expander. The transfer valve head upper seat is also partially oil-cooled, thus providing partial cooling of the transfer valve head. Also, the transfer valve stem is purposefully designed with a slight narrowing in the area where the transfer valve stem contacts the transfer valve o-ring seal during the travel towards opening of the transfer valve, temporarily reducing friction between the stem and the seal for that fractional moment and allowing the transfer valve head to adequately seal against the upper transfer valve head upper seat. Finally, the transfer valve head is provided with a slight physical projection into the expansion chamber, which allows it to operate similarly to that of a steam engine bash-valve, thus ensuring that the transfer valve does in fact break free and open at TDC. A second teflon-and-stainless steel spring seal exhaust valve stem seal ensures that the pressurized oil will not contaminate the higher pressure working fluid.

[0147] The converted prime mover's connecting rod is stock, but the original piston has been replaced with a titanium follower device and force plates mounted in the piston cylinder that converts the rotary motion of the crankshaft into linear motion. The diameter titanium rod passes through a teflon-and-stainless steel spring seal at the top of the prime mover that can seal against oil on the one side and substantial pressure on the other. The diameter titanium rod is attached on the lower end to the titanium follower device and on the upper end to the single contiguous piston, which is thus cyclically driven linearly from TDC to BDC.

[0148] All coiled tube heat exchangers used within the EISG CCVC testbed use lathe-machined multi-spiraled helical ribbing constructed in the manner illustrated and described in U.S. patent application Ser. No. 18/362,951, FIG. 9 and FIG. 10.

OperationFirst Embodiment

[0149] Following the flow process illustrated in FIG. 1, FIG. 2, and FIG. 3, starting at BDC in the engine (shown in FIG. 2), ideally all the gases within the engine are at the same pressure, as will be shown, which is the pressure of the feed gas exiting the gaseous radiator (boxed label 1 in FIG. 1 and FIG. 3). A full pressurized charge of working fluid has just passed through the displacer #1 intake check valve (boxed label 2 in FIG. 1 and FIG. 3) and been taken into displacer #1 (boxed label 3 in FIG. 1 and FIG. 3). During the move in the engine to TDC (shown in FIG. 1), the pressurized charge of working fluid is displaced through the displacer #1 exhaust check valve (boxed label 4 in FIG. 1 and FIG. 3), through the heat input side of the coiled tube exhaust heat exchanger (boxed label 5 in FIG. 1 and FIG. 3), through the electrically heated coiled tube heater (boxed label 6 in FIG. 1 and FIG. 3), and into displacer #2 (boxed label 7 in FIG. 1 and FIG. 3). This is an isochoric (constant volume) process that creates an increase in the temperature and thus pressure of the working fluid thus captured at constant volume between displacer #1 (3) and displacer #2 (7).

[0150] Simultaneously at BDC, the expander transfer/intake valve (boxed label 8 in FIG. 1 and FIG. 3) is physically closed by the closing action of the exhaust valve's (boxed label 10 in FIG. 1 and FIG. 3) stem-mounted arm, compressing the transfer valve's (8) stainless steel spring (not shown) which is biased towards open. During the following engine move to TDC, the hot, low pressure charge in the expander (boxed label 9 in FIG. 1 and FIG. 3) is displaced past the now-open expander exhaust valve (10), forcing open and displacing past the expander check valve (boxed label 11 in FIG. 1 and FIG. 3), which is biased closed by a stainless steel spring (not shown), displaced through the heat output side of the coiled tube exhaust heat exchanger (5), displaced through the water-cooled coiled tube cooler (boxed label 12 in FIG. 1 and FIG. 3), and finally displaced into the combination displacer #3/compressor (boxed label 13 in FIG. 1 and FIG. 3). This is an isochoric process that creates a decrease in temperature and thus pressure of the working fluid thus captured at essentially constant volume between the expander (9) and the combination displacer #3/compressor (13).

[0151] Starting slightly before TDC is reached, the expander exhaust valve (10) is closed. The transfer valve's (8) stainless steel spring (biased towards open) then propels it open, thus connecting the expander (9) to the hot, high pressure working fluid captured between the displacer #1 exhaust check valve (4) and the expander exhaust valve (10).

[0152] Starting at TDC, displacer #2 (7) displaces hot, high pressure working fluid back through the heater (6), past the transfer valve (8), and into the expander (9). Simultaneously, the pressure drops due to expansion within the expander (9), overcoming some working fluid expansion via the heater (6) as the fluid from displacer #2 (7) flows through it. Some additional flow (and some additional working fluid expansion) also proceeds as pressure drops within the various connecting manifolds (not shown) and within the heat input side of the coiled tube exhaust heat exchanger (5).

[0153] Simultaneously at TDC, the displacer #1 exhaust check valve (4), biased towards closed by a stainless steel spring (not shown), closes as the pressure is equalized across it. The remnant gas still trapped in displacer #1 (3) expands, eventually equalizing pressure across the displacer #1 intake check valve (2) and overcoming that valve's stainless steel spring (not shown) bias towards closed. Consequently, relatively cold ideally constant pressure working fluid flows into displacer #1 (3), eventually fully charging it by BDC, at which time the displacer #1 intake check valve (2) will close.

[0154] Finally, near TDC, as noted above, the expander exhaust valve (10) will be closed, freeing the transfer valve to open when the pressure differential is equal on both sides of the transfer valve (8), thus permitting the stainless steel spring bias to open the transfer valve (8). Simultaneous to the closing of the expander exhaust valve (10), the expander check valve (11) will be closed due to its stainless steel spring bias towards closed. The displacer #3/compressor (13) will now begin compressing the colder, lower pressure working fluid backwards into the volume between the displacer #3/compressor (13) the expander check valve (11), and the compressor check valve (boxed label 14 in FIG. 1 and FIG. 3). Eventually, the pressure inside that volume will equalize to the pressure in the gaseous radiator (1). The compressor check valve (14) will then open as its stainless steel spring (not shown) bias towards closed is overcome. The displacer #3/compressor (13) will then begin exhausting re-pressurized working fluid past the compressor check valve (14), through the gaseous radiator (1), past the displacer #1 intake check valve (2), and into displacer #1 (3), ideally at constant pressure.

[0155] And so on, beginning again at paragraph 66 above.

DescriptionSecond Embodiment

[0156] Modifications to the EISG CCVC testbed, aka hybrid Ericsson/Stirling closed cycle heat engine are herein proposed that will increase the testbed's potential and delivered thermal efficiency. These modifications will leave much of the EISG CCVC testbed unmodified, and may thus be seen both as a practical means for testing the usefulness of the modifications prior to the development of eventual production machinery and as a means for describing and detailing herein the proposed modifications. Changes beyond the First Embodiment labels will therefore be limited, and will be described below. Where no changes are incurred, FIG. 1 and FIG. 3 are referred to for unchanged labeling.

Replacing a Part of the EISG CCVC Testbed Recuperation Process with Regeneration

[0157] The existing EISG CCVC testbed uses a device called a recuperator to capture otherwise-waste exhaust heat. There is an alternative to recuperation called regeneration. A regenerator is advantaged over a recuperator in its ability to permit an exchange of heat with both a greatly-reduced internal volume and a much faster heat exchange rate. Decreasing internal volume for isochoric heat transfers will increase the theoretical thermal efficiency of a heat engine. A faster heat exchange rate will increase the rpm for delivering power output and thus increase the power output for a given engine mass.

[0158] Two basic types of regeneration are presently utilized. The first may be termed single stream regeneration (SSR). The second may be termed dual-stream regeneration (DSR).

[0159] DSR is generally accomplished by either switching the two counter-flowing streams through a single regenerator core, which is accomplished by either ducts/ports, which may be termed a ducted DSR or DDSR, or by valves, which may be termed a valved DSR or VDSR.

[0160] In addition, there is a variant in which may be termed a valve-switched DSR (VSDSR) or possibly a duct/port-switched DSR (DSDSR). In such a variant, there are at least two and possibly more regenerator cores which are switched out by ducts/ports such that one regenerator core or set of regenerator cores is thermally charged while the other regenerator core or set of regenerator cores is thermally depleted. One design for a possible VSDSR was proposed in U.S. patent application Ser. No. 17/746,848, FIG. 6.

[0161] As a means for partially reducing the volume of the present EISG CCVC testbed recuperator and thus increasing the potential thermal efficiency, a kind of combined exhaust heat SSR/cooler is herein proposed.

Replacing the Hybrid Ericsson/Stirling Closed Cycle Heat Engine with a Hybrid Rankine/Stirling Closed Cycle Heat Engine

[0162] A unique characteristic of the valved cell process that underlies the EISG CCVC testbed is the ability to connect previously disconnected processes. An Ericsson-like or a Rankine-like process may be integrated with the Stirling-like processes of the EISG CCVC testbed, creating a hybrid Ericsson/Stirling engine that uses constant volume regeneration or a hybrid Rankine/Stirling engine that will increase the net work delivered by the expander. In the case of the proposed modified EISG CCVC testbed, the existing combined displacer/compressor can be converted to a displacer only. That in turn increases delivered thermal efficiency.

[0163] Note that the two modifications included in the proposed second embodiment are not mutually exclusive.

OperationSecond Embodiment

[0164] For a hybrid Rankine/Stirling closed cycle engine, following the flow process illustrated in FIG. 1 through FIG. 7, and starting again at BDC in the engine (FIG. 5), it is assumed that the pressure and temperature of the feed vapor exiting the steam generator (boxed label 15 in FIG. 4 and FIG. 6, which replaces boxed label 1) is the same as for the gaseous radiator (1). A full pressurized charge of working fluid has just passed through the displacer #1 intake check valve (2) and been taken into displacer #1 (3). During the move in the engine to TDC, the pressurized charge of working fluid is displaced through the displacer #1 exhaust check valve (4), through the heat input side of the coiled tube exhaust heat exchanger (5), through the electrically heated coiled tube heater (6), and into displacer #2 (7). However there has been a change in the source of heat for the exhaust heat exchanger (5). Instead of the source of exhaust heat coming directly from the exhaust of the expander (9) as it passes through to the displacer #3/compressor (13), the source of heat derives from an SSR/cooler (boxed label 16 in FIG. 4 and FIG. 6, which replaces boxed label 12). In addition, the displacer #3/compressor (13) has been replaced by displacer #3 (boxed label 17 in FIG. 4 and FIG. 6, which replaces boxed label 13), with the SSR/cooler (16) sitting between displacer #3 (17) and the ECV (11). Finally, a new valve, called a main engine exhaust valve (boxed label 18 in FIG. 4 and FIG. 6) has been added to the EISG CCVC testbed. The new main engine exhaust valve (18), being between the the expander check valve (11) and the new SSR/cooler (16), also subtly changes the plumbing between the displacer #1 exhaust check valve (4) and displacer #2 (7), which no longer shows a route between the two that also passes through the heater (6). Instead, the hot exhaust working fluid exhausts through the main engine exhaust valve (18), and through the heater (6) before entering the exhaust heat exchanger (5). This subtle change shortens the path of the working fluid displacing from displacer #1 exhaust check valve (4) to displacer #2 (7), reducing the volume between and thus increasing the potential isochoric thermal increase in temperature and pressure.

[0165] After passing through the repositioned exhaust heat exchanger (5), the exhaust gases may still be of sufficient heat content to aid in the generation of steam vapor, shown by the exhaust gases being passed through said steam generator (15). The further cooled exhaust gases are now passed through a condenser (boxed label 19 in FIG. 4 and FIG. 6), into a fluid storage tank (boxed label 20 in FIG. 4 and FIG. 6), then through a liquid pump (boxed label 21 in FIG. 4 and FIG. 6). And so on.

[0166] FIG. 7 indicates an alternative place for the main engine exhaust valve (boxed label 22 in FIG. 7, which replaces boxed label 18).

[0167] For an hybrid Ericsson/Stirling closed cycle engine, substitute a gaseous radiator (1) for the condenser (19) and a compressor (13) for the liquid pump (21).

DescriptionThird Embodiment

[0168] Modifications to the EISG CCVC testbed are herein proposed that will increase the testbed's potential and delivered thermal efficiency. These modifications will leave much of the EISG CCVC testbed unmodified, and may thus be seen both as a practical means for testing the usefulness of the modifications prior to the development of eventual production machinery and as a means for describing and detailing herein the proposed modifications. Changes beyond the First and Second Embodiment labels will therefore be limited, and will be described below. Where no changes are incurred, FIG. 1, FIG. 3, FIG. 4, FIG. 6, and FIG. 7 are referred to for unchanged labeling.

Replacing the EISG CCVC Testbed Exhaust Heat Exchanger with a VDSR

[0169] The existing EISG CCVC testbed uses a recuperator to exchange heat isochorically between the expander exhaust and the displacer #1 (3) to displacer #2 (7) displacement. Even in the proposed Second Embodiment, a recuperator (5) was still show. However, by replacing the recuperator (5) with an SSR/cooler combination (16), as shown in the Second Embodiment, the syncopation between the two isentropic displacement processes found in the existing EISG CCVC testbed is changed dramatically, such that the final exhaust from displacer #3 (17) now occurs out of phase with the displacement process between displacer #1 (3) and displacer #2 (7).

[0170] That means it is now possible, as stated above, to tap into the waste heat flowing out of the SSR to directly thermally charge a single regenerator core valved dual-stream regenerator, or VDSR heat exchanger, greatly simplifying the process of converting the EISG CCVC prototype to replace the existing recuperator (5) with (a) an exhaust gas regenerator and (b) an isochoric displacement regenerator. That in turn will greatly reduce the dead space volumes within the EISG CCVC prototype, further increasing the potential thermal efficiency.

Exhaust Cylinder Displacement Versus Exhaust Compounding.

[0171] In replacing the gaseous compression process with the Rankine process, it becomes possible to extend the expansion process a great deal over the standard Stirling expansion process. One means for accomplishing this is via exhaust compound-expansion. For example, the present EISB CCVC testbed expansion chamber, as mentioned above equals 13.5 cubic inches, and the displacer volumes equals the 4.86 cubic inches. Even assuming dead space, that would limit the expansion ratio to 13.5/4.86 or 2.78X.

[0172] If the displacer were replaced with a 27 cubic inch expander, then the expansion ratio would potentially double to 5.5X, creating significantly more net power output per crank cycle. That would, of course, also significantly lower the post-expansion exhaust pressure. However, with the SSR exhaust system, a great deal of the thermal content left behind in the regenerator during the exhaust stroke can be recovered in the following secondary exhaust stroke, allowing for both additional net power out but also a significant amount of waste heat recovery. Finally, the exhaust resistance of pumping the expanded and thus lower pressure gases out of the 2nd expander would mean less exhaust work in is required, also aiding the net work out per cycle.

[0173] It is also possible for an isochoric displacer #3 (17) to exhaust to a compounding expander as an alternative to changing out displacer #3 (17) for an expander. Again, this is made easier when the modified EISG CCVC testbed uses the proposed modified Rankine process.

Replacing the EISG CCVC Testbed Heater with a VSDSR Heater

[0174] The existing EISG CCVC testbed uses a recuperator heater (6) to add source heat to the engine during isochoric heating. It is herein proposed that a valve-switching dual-stream regenerator (VSDSR) heater be used in the EISG CCVC testbed to replace the existing recuperator heater (6).

Replacing the EISG CCVC Testbed Cooler with a VDSR Cooler

[0175] The existing EISG CCVC testbed uses a recuperator cooler (12, 16) to remove heat from the engine during isochoric cooling. It is herein proposed that a valved dual-stream regenerator (VDSR) cooler be used in the EISG CCVC testbed to replace the existing recuperator cooler (12, 16).

[0176] These changes shorten the paths of the working fluids between (a) displacer #1 (3) and displacer #2 (7) and (b) the expander (9) and displacer #3 (17) or expander #2 (30), reducing the volume between them and thus increasing the potential isochoric thermal changes in temperature and concomitant pressure.

OperationThird Embodiment

[0177] Following the flow process illustrated in FIG. 1 through FIG. 7, and starting again at BDC in the engine (FIG. 5), a full pressurized charge of working fluid has just passed through the displacer #1 intake check valve (2) and been taken into displacer #1 (3). Looking backwards to the previous move from TDC to BDC, it is assumed to be the case that the pressure within the expander (9) was significantly above the pressure within the steam generator (15) at TDC, and it is likewise assumed to be the case that, when the expander exhaust valve (10) opens at BDC, the pressure within the expander (9) is at about the same pressure as the pressure within the steam generator (15).

[0178] That being the case, if an isochoric displacement from BDC to TDC occurs through the SSR/cooler (16) and into displacer #3 (17), then the pressure will be significantly lower than the pressure in the steam generator (15) when displacer #3 (17) almost reaches TDC and the expander exhaust valve (11) closes slightly early.

[0179] However, because the engine is now using a pressurized liquid-to-pressurized-vapor combined Rankine/Stirling process, it is perfectly permissible for the newly-added main engine exhaust valve (18) to open and release the working fluid either at that lower pressure or even permit some explosive decompression through the air engine exhaust valve (18, 22) to an even lower pressure. Assuming that to be the case, displacer #3 (17) now exhausts at either the pressure following displacement or some lower pressure.

Exhaust Cylinder Displacement Versus Exhaust Compounding.

[0180] Likewise, it is perfectly permissible that, instead of a pure isochoric displacement process, an exhaust gas compound expansion process is created by, essentially, replacing displacer #3 (13) with a second expander (boxed label 30 in FIG. 8, FIG. 12 and FIG. 13, replacing boxed labels 13 and 17) takes place that lowers the gas pressure even more, as mentioned above.

[0181] Note that, per FIG. 7, in either case the exhaust flows back through the SSR/cooler (16), back through the heater (6), and through the exhaust heat exchanger (regenerator) (5), where it exchanges heat with the cool higher pressure gas on the other side of the recuperator (5) flowing between displacer #1 (4) and displacer #2 (7).

Replacing the EISG CCVC Testbed Exhaust Heat Exchanger with a VDSR

[0182] In FIG. 8 and FIG. 12, however, something else has been added: The recuperator (5) is replaced with a valved dual stream regenerator or VDSR heat exchanger (boxed label 24 in FIG. 8, FIG. 12, FIG. 13, and FIG. 14, replacing boxed label 5). Note that the main engine exhaust valve (boxed label 32 in FIG. 8, FIG. 12, FIG. 13, and FIG. 14, that replaces boxed label 18 and boxed label 22) is shown on the cold side of the VDSR heat exchanger (24). That means that, if desired, the main engine exhaust valve (32) can be made to exhaust the gases at TDC upstream of expander check valve or ECV #2 (boxed label 31 in FIG. 8, FIG. 12, and FIG. 13), and ECV #5 (boxed label 40 in FIG. 14) into a much lower pressure environment, including that of ambient atmospheric pressure.

[0183] This may require some explosive decompression of trapped working fluid in the VDSR heat exchanger (24), for the following reason: As previously stated, the highest temperature and concomitant pressure occurs at approximately TDC at the end of the isochoric displacement process between displacer #1 (3) and displacer #2 (7). Note the addition in FIG. 8 and FIG. 12 of a displacer #2 intake check valve (boxed label 23 in FIG. 8, FIG. 12, FIG. 13, and FIG. 14) which is biased towards closed by a stainless steel spring (not shown). That implies that, at TDC, the displacer #2 intake check valve (23) will close. Also at TDC, the main engine exhaust valve (32) will be closed, as will ECV #2 (31) or ECV #5 (40). If the displacer #1 actuated exhaust valve (23) is also closed, then high pressure gas will be effectively trapped inside the VDSR heat exchanger (24).

[0184] Hence, displacer #1's exhaust valve (23) has been changed from a check valve (3) to permit a reverse expansion of gases trapped in the VDSR heat exchanger (24) back into displacer #1 (3). That is also why it is essential that the VDSR heat exchanger (24) be as compact as possible: The larger the internal volume of the VDSR heat exchanger (24), the more re-expansion of its trapped high pressure gas back into displacer #1 (3) will be required. That in turn will impact the amount of charge that the engine can receive into displacer #1 (3) during its intake stroke, which in turn will either increase or reduce the molal count of the gas that circulates per cycle, which in turn will increase or reduce the power density that the modified EISG CCVC testbed can achieve per cycle, which may positively or negatively impact potential thermal efficiency.

[0185] Determining the optimal balance that will generate maximum thermal efficiency for the modified EISG CCVC testbed between re-expansion back into displacer #1 (3) of trapped VDSR heat exchanger (24) gas versus explosive decompression out of the VDSR heat exchanger (24) via the main engine exhaust valve (32) will need to be determined experimentally.

[0186] Starting once again at BDC in the engine (FIG. 10), a full pressurized charge of working fluid has just passed through the displacer #1 intake check valve (2) and been taken into displacer #1 (3). The displacer #1 activated exhaust valve, being closed by a biased closed stainless steel spring (not shown), can maintain pressure substantially higher than exists within the recently-thermally-charged VDSR heat exchanger (24). However, to match pressure within the regenerator and within the volumes between displacer #3 or expander #2 (30) and ECV #1 (11), the main engine exhaust valve is closed early, permitting some recompression into said volumes between displacer #3 or expander #2 (30) and ECV #1 (11) to match the pressure within displacer #1 (3), as well as the pressure within the expander (9) and the volume between the expander (9) and the displacer #2 intake check valve (25). At BDC, therefore, pressure has been ideally equalized across all internal spaces within the modified EISG CCVC testbed. Note that the transfer valve (8) has just been closed as the expander exhaust valve (10) has opened.

Replacing the EISG CCVC Testbed Heater with a VSDSR Heater

[0187] In FIG. 12, a constant pressure heat transfer vapor system, which is a pressurized quantity of the same vapor being used in the engine and at the same pressure as the vapor in the engine at BDC, is connected to a thermally discharged regenerator core of a VSDSR heater (boxed label 26 in FIG. 8, FIG. 12, FIG. 13, and FIG. 14, replacing the heater 6, and referencing for an example of a VSDSR device U.S. patent application Ser. No. 17/746,848, FIG. 6). Starting at the previous BDC of the engine, a heat source (boxed label 27 in FIG. 8, FIG. 12, FIG. 13, and FIG. 14) begins thermally charging said thermally discharged regenerator core by (A1) flowing at constant pressure said high temperature constant pressure heat transfer fluid (A2) from said heat source (27), through a heat transfer fluid intake valve connected to the hot side of said thermally discharged regenerator core, (A3) through said thermally discharged regenerator core, (A4) through a heat transfer fluid exhaust valve attached to said regenerator core's cold side, and (A5) back to said heat source be reheated (27).

[0188] At the following TDC of the engine, (A6) the now thermally-recharged regenerator valve-switches to disconnect from the constant pressure heat transfer system (27) and connects to ECV #2 (31). As it moves away from TDC, displacer #3 (30) begins recompressing the working fluid within the volumes between it, ECV #1 (11), and ECV #2 (31), while simultaneously the VSDR head exchanger (24) drops in pressure either due to expansion back into displacer #1 (3) via the displacer #1 actuated exhaust valve (23) or by explosive decompression from opening of the main engine exhaust valve (32) or both. When pressures equalize, displacer #3 (30) begins exhausting back through the cooler (29), back through the exhaust SSR (28), past ECV #2 (31) through the thermally-recharged regenerator of the VSDSR heater (26), through the VSDR heat exchanger (24), and out of the main engine exhaust valve (32), eventually reaching BDC in the engine.

[0189] Meanwhile, simultaneous to the move from the previous BDC to the TDC of the engine, with the main engine exhaust valve (32) closed, the ECV #2 (31) closed, the displacer #2 intake check valve (25) about to open, the displacer #1 actuated exhaust valve (23) about to open, and the pressures all the same throughout the engine, it is now possible to simultaneously valve-switch out yet another thermally discharged regenerator core, this one for use following the isochoric displacement from displacer #1 (3) into displacer #2 (7), finishing at TDC. Further travel from BDC towards TDC will initiate an isochoric heat input process as working fluid is passed through the VDSR heat exchanger (24) fully charged regenerator core. The second charged regenerator core would then be available by valve-switching to use during the displacement/expansion process, where working fluid is displaced out of displacer #2 (7), through the cold side and out the hot side of the second charged regenerator core (26), past the transfer valve (8) and into the expander (9). In other words, the valve-switching would involve swapping four regenerator cores at BDC, and the VSDSR heater (26) would thus be made up of those four cores, their switching valves, and connecting manifolds.

[0190] In FIG. 13, an alternative is shown where heater #2 (boxed label 33 in FIG. 8 and FIG. 13) serves to supply source heat to the working fluid during the isochoric displacement from displacer #1 (3) to displacer #2 (7), and the first heater is used only to supply heat to the working fluid during the displacement-expansion process from displacer #2 (7) through the transfer valve (8) and into the expander (9). Note that heater #2 (33) can be a second VSDSR heater.

[0191] FIG. 12 and FIG. 13 differ primarily in the pathway for adding source heat to the proposed modified EISG CCVC testbed. An advantage of the FIG. 12 system is that the VDSR heat exchanger (24) only needs to transfer otherwise/waste exhaust heat. Also, the displacer actuated exhaust valve (23) will be subjected to lower temperature heat. Also, the exhaust gas will not have to undergo a recompression to equalize pressure. The disadvantage is the addition an additional VSDSR heater's volume. However, this advantage may disappear if post-displacement heating is done differently, for example by using internal combustion.

Replacing the EISG CCVC Testbed Cooler with a VDSR Cooler

[0192] Further travel from BDC towards TDC will likewise initiate an isochoric heat removal process as working fluid is passed through the exhaust SSR (28) and VSDR cooler (boxed label 35 in FIG. 8 and FIG. 14, replacing boxed label 12 and 29), as shown in the proposed modified EISG CCVC testbed move from FIG. 8 through FIG. 11 and as shown in the schematic of the processes in FIG. 14.

[0193] Proceeding on with the flow process, FIG. 8 through FIG. 11 and FIG. 14 assume the exhaust process is an isochoric displacement process. Consequently, the desire is to reach the lowest possible temperature by the end of the process with the least amount of dead space, i.e., space that isn't found in either the expander (9) or displacer #3 (boxed label 38 in FIG. 8 and FIG. 14, replacing boxed label 13, 29, and 30). That is partially achieved replacing the recuperator/exhaust heat exchanger (5) with an exhaust SSR (28), and partially achieved by replacing the exhaust heat exchanger (5) with the VDSR heat exchanger (24). The final means to reducing dead space is to replace the cooler (12, 29) with the VDSR cooler (35).

[0194] As can be seen in FIG. 8 and FIG. 14, the only changes required to replace the EISG CCVC testbed cooler with a VDSR cooler are limited to the isentropic displacement process between the expander (9) and displacer #3 (38). From BDC, as the exhaust flows out of the expander (9), past the expander exhaust valve (10), past ECV #1 (11), it enters and flows through the exhaust SSR (28). from there it passes through a new regenerator-to-regenerator check valve (boxed label 34 in FIG. 8 and FIG. 14) and enters the VDSR cooler (35). The VDSR cooler as shown may flow directly into displacer #3 (38) or it may flow through another check valve, ECV #3 (boxed label 37 in FIG. 8 and FIG. 14). Displacer #3 (38) in the exiting EISG CCVC tested exhausts through compressor check valve (14), now called ECV #4 (14).

[0195] In essence, during the move from BDC to TDC, the working fluid exhausted from the expander (9) will enter displacer #3 (38) via either the VDSR cooler (35) or ECV #3 (37), and during the move from TDC to BDC, the working fluid from displacer #3 (38) will bypass the VDSR cooler (35) and go to the cold side of the exhaust SSR (28). This will have the effect of reducing the cooling requirement for the VDSR cooler (35) and increasing the temperature exhausted out of the hot side of the exhaust SSR (28). Since reducing the cooling requirement will potentially reduce the internal volume of the SSR for a given amount of temperature drop, any increase in manifolding due to the bypass may be accounted for.

[0196] For an hybrid Ericsson/Stirling closed cycle engine, substitute a gaseous radiator (1) for the condenser (19) and a compressor (13) for the liquid pump (21).

DescriptionFourth Embodiment

[0197] Modern Rankine cycles operate at supercritical H20 steam levels to attain decent efficiencies. On the poles of Earth's Moon, special areas called Permanently Shadowed Regions (PSRs) exist that never see sunlight. In the depths of some polar craters that never see sunlight, extremely low temperatures approach 100 K.

[0198] One usefulness of Rankine/Stirling CCVC engines may be their ability to operate with very high power density and good efficiency at low temperatures. With careful design, a peak temperature of 810 K (1,000 deg F.) may be sustainable with teflon seals and bearings and no requirement for lubricant or coolant.

[0199] Some potential Rankine/Stirling CCVC working fluids can be found to be extremely useful in proximity to PSRs. One example is CO2, which can attain supercritical levels at temperatures of about 300 K (80 deg F.) and about 1,000 psi. A heat engine that can exhaust at a final waste heat of perhaps 100 deg F. can thus easily turn solid CO2 (dry ice) at 1,000 psi into a supercritical gas. Also, at an exhaust pressure of even 1 atm, CO2 gas can be converted back to dry ice at as high a temperature as 195 K (78 deg C.), which should be attainable in most PSRs.

[0200] The theoretical Carnot thermal efficiency ((ThTc)/Th) of a heat engine with a source temperature of 810 K (1,000 deg F.) and a theoretical sink temperature of 195 K is ((810-283)/810=) 0.65 or 65%. Coupled with the extremely high delivered thermal efficiency of a compressor-less engine and the very low relative peak temperature, it's likely that a delivered thermal efficiency could approach 50%. For solar energy, that means possibly 40% of the focused solar radiant energy can be converted into electricity, possibly matching if not exceeding the best that a solar-powered Stirling engine has ever achieved.

OperationFourth Embodiment

[0201] It is herein proposed that, in a Rankine/Stirling CCVC engine such as has been described above, working fluids that are liquids and/or solids be (A) compressed, (B) converted to supercritical vapors, (C) passed through the CCVC isochoric processes to (1) permit the efficient recycling of otherwise-waste exhaust heat, and (2) be superheated, (D) be expanded to produce (1) net work out and (2) high quality waste heat for recycling purposes, and (E) any remaining waste heat in the final exhaust from the engine be used to help vaporize said liquids and/or solids in the first place.

[0202] It is herein further proposed that, where access to sufficiently low temperatures is available, liquids and/or solids which can be converted to supercritical vapors at those low temperatures be utilized in Rankine/Steriling CCVC engines as a means of expanding the usefulness of low temperature engines such as non-lubricated and/or non-cooled engines.

DescriptionFifth Embodiment

Open Cycle CCVC-Based Internal Combustion Engines

[0203] Unlike other closed-cycle hot gas engines, a valved cell engine can be open cycle, closed cycle, or even both open and closed cycle. That is because the concept of the valved cell essentially is a means to attach seemingly disparate heat engine processes together. In the original valved cell patents, valved cells were used to connect an externally-pressurized gas to an internally pressurized gas. In essence, converting a closed cycle valved cell (CCVC) to an open cycle valved cell (OCVC) is as simple as taking compressed air into displacer #1, and later exhausting it from displacer #3. Note that even then, all heat can be added from an external heat source in any of the manners proposed above. In fact, some heat can be added that way, and additional heat can be added by injecting fuel into the preheated, pressurized gas, at any of several places. Also, the fuel can be atomized and injected liquid, as is presently done with diesel engines, or it can be vaporized and valved cell-injected gas, as was proposed in the original valved cell patents.

[0204] For an open cycle based on the EISG CCVC testbed, or Open Cycle Valved Cell (OCVC) isochoric fully regenerating heat engine, the working fluid can be compressed air, the source heat input can be the internal combustion of a fuel, and the final exhaust can be vented to the atmosphere. Note that a fully regenerating OCVC with isochoric internal combustion can be thought of as a fully regenerating Otto/Stirling hybrid cycle engine, or with isobaric combustion, a fully regenerating Diesel/Stirling hybrid cycle engine, or with isothermal combustion, a fully regenerating Carnot/Stirling hybrid cycle engine.

Semi-Open Cycle CCVC-Based Internal Combustion Engines

[0205] Two examples of semi-open CCVC-based internal combustion engines have been suggested.

H2Enriched Steam Engines

[0206] Adding H2 to pressurized steam to create a H2-spiked working fluid that will not in itself combust allows such a working fluid to be taken into displacer #1 in a CCVC engine such as described above that has been converted to an OCVC engine. Following or even during the displacement from displacer #1 to displacer #2, injecting a quantity of O2, as with a valved cell, will literally convert 2 molecules of O2 and a molecule of H2 into 2 molecules of H2O and release heat, probably without even requiring a spark plug or glow plug. The exhaust, barring a few molecules that didn't get converted, is thus more steam than was originally put into the engine, plus work out, plus waste heat. It can be called a semi-closed cycle because the H2O thus created can be broken back down into its H2 and O2 constituents, as by electrolysis, and recycled continually.

O2Enriched Steam Engines

[0207] Alternatively, rather than adding H2 to steam, O2 or even H2O2 could be added to steam. H2 would then be injected following or even during isochoric displacement, once again converting 2 molecules of H2 and 1 of O2 into steam, allowing the eventual breaking of the resulting H20 into separate H2 and O2 gases, as with electrolysis, thus creating a semi-closed cycle.

OperationFifth Embodiment

[0208] In a conversion of a regenerating CCVC engine into an air-breathing regenerating OCVC engine, the use of internal combustion as a means of increasing the thermal efficiency of said air-breathing regenerating OCVC engine.

[0209] In a conversion of a regenerating CCVC engine into an air-breathing regenerating OCVC engine, the use of internal combustion by means of liquid or solid fuel injection as a means of increasing the thermal efficiency of said air-breathing regenerating OCVC engine.

[0210] In a conversion of a regenerating CCVC engine into a regenerating OCVC engine, the use of internal combustion by means of liquid or solid oxidizer injection as a means of increasing the thermal efficiency of said regenerating OCVC engine.

[0211] In a conversion of a regenerating CCVC engine into a regenerating OCVC engine, the use of internal combustion by means of both liquid and/or solid and/or gaseous fuel and liquid and/or solid and/or gaseous oxidant injection as a means of increasing the thermal efficiency of said air-breathing regenerating OCVC engine.

[0212] In a conversion of a regenerating CCVC engine into a regenerating OCVC engine, the use of internal combustion by means of gaseous fuel injection by valved cell means and/or gaseous oxidizer injection by valved cell means for increasing the thermal efficiency of said regenerating OCVC engine. As an example of how a valved cell means can be used to inject a gas into a regenerating OCVC, see FIG. 8 through FIG. 11 for an example. As shown, a valved cell gaseous injector (boxed label 41 in FIG. 8 and FIG. 9) with a closing solenoid and a stainless steel spring (not shown) that is biased to open when pressures equalize at TDC in the OCVC engine, has been opened at TDC in such a manner as to present from the valved cell a measured quantity of either a gaseous fuel such as H2 or a gaseous oxidizer such as O2 to, respectively, either a working fluid mix with a quantity of gaseous fuel or a working fluid mix with a quantity of gaseous oxidizer. Said quantity of gaseous fuel or gaseous oxidizer may then be actively forced into the expander mix, as with a plunger, or passively displaced into the expander mix, as by a constant pressure addition as the expander mix is both expanded and dropped in pressure, in the manner disclosed in U.S. Pat. Nos. 4,817,388 and 5,179,839. Following said injection of gaseous fuel or gaseous oxidizer, as shown in FIG. 10 and FIG. 1.11, said valved cell gaseous injector (boxed label 42 in FIG. 10 and FIG. 11) shall be closed to permit or finalize the recharging of the valved cell, in the manner disclosed in U.S. Pat. Nos. 4,817,388 and 5,179,839.

DescriptionSixth Embodiment

Semi-Open Cycle CCVC-Based Combined B/E Half-Cycle Heat Engines

[0213] For the purposes of describing these half-cycles, the The chemo/thermodynamic heat engine cycle analyzed herein is the classic reversible cyclohexane: benzene+H2 cycle or C6H12<=>C6H6+3H2 cycle analyzed in U.S. Pat. No. 3,225,538.

[0214] As noted earlier, U.S. Pat. No. 3,067,594 proposed an open-cycle Bland/Ewing chemo-thermodynamic process, U.S. Pat. No. 3,225,538 proposed a closed-cycle Bland/Ewing chemo-thermodynamic process, and U.S. Pat. No. 3,871,179 proposed the application of the B/E cycle to the classic Stirling cycle. U.S. patent application Ser. No. 18/095,463 disclosed the concept of creating a unique full B/E chemo/thermodynamic cycle as disclosed in U.S. Pat. No. 3,225,538 by connecting two semi-open chemo/thermodynamic half-cycles; a semi-open endothermic half-cycle, and a semi-open exothermic half-cycle. For the two half-cycles, the endothermic cycle is C6H12=>C6H6+3H2, and the exothermic cycle is C6H12<=C6H6+3H2. Note that in either direction, the exact same amount of thermal energy is stored as is released. However, the endothermic half-cycle occurs at a much higher temperature for a given pressure than the exothermic half-cycle. That is, the endothermic half-cycle requires higher quality heat than the exothermic half-cycle returns.

[0215] Both half-cycles have one purpose in common; generate net work out. But for the endothermic half-cycle, a second purpose is to store thermochemical energy, and for the exothermic half-cycle, it's main purpose is to use that stored energy efficiently to generate net work. Note that by far the largest amount of energy used to power the endothermic half-cycle is stored chemically. That in turn means that the largest amount of net work that will be produced by the two half-cycles will be produced by the exothermic half-cycle. It also means that maximizing the thermal efficiency of the exothermic half cycle is what is going to determine just how efficient both half-cycles are combined.

[0216] There is one unique result of the C6H12=>C6H6+3H2 endothermic half-cycle that can be seen as beneficial for converting heat into work, and that is this particular endothermic half-cycle's ability to create a kind of chemical expansion process. Note that C6H12=>C6H6+3H2 literally turns a single molecule into 4 molecules; one molecule of benzene, and 3 molecules of hydrogen gas.

[0217] In a heat engine, it is useful to find a way to pressurize a gas, and it turns out that, by pressurizing the C6H12 before it is converted into C6H6+3H2, 4 times as many molecules are generated at any given conversion pressure. In other words, one way to look at the C6H12=>C6H6+3H2 endothermic half-cycle is as a kind of chemical H2 pressurization system.

OperationSixth Embodiment

A Rankin/Stirling Fully-Regenerating CCVC-Based Endothermic Semi-Open Half-Cycle Heat Engine

[0218] The approach being proposed for the endothermic half-cycle essentially uses the endothermic conversion to produce pressurized H2 gas. For example: [0219] 1. Pressurize the liquid C6H12 reactant to some desired pressure. [0220] 2. Heat the reactant to the vaporization point. [0221] 3. Vaporize the reactant. [0222] 4. Raise the pressure of the vaporized reactant with a compressor. The purpose of this is to increase the temperature at which the eventual vapor product (C6H6) will condense over the temperature at which the C6H12 liquid at the pressure given it in step 1 above will evaporate. C6H12 and C6H6 temperatures and heats of condensation/vaporization that are very close to one another (at 14.7 psi, C6H12 boils at 343.9 K with a standard heat of vaporization of 380 KJ/kg, while C6H6 boils at 353.2 K with a standard heat of vaporization of 433 KJ/kg). Consequently, condensing slightly higher pressure C6H6 will theoretically supply more than the required heat of vaporization of C6H12, removing the thermal cost of vaporizing the C6H12 from the required heat in to the proposed process, as will be shown. [0223] 5. Preheat the reactant by passing it through a first heat exchanger to the temperature at which the reactant, at the given pressure, will convert the reactant to product in an endothermic catalytic converter. [0224] 6. Convert the vaporous C6H12 reactant at constant pressure and temperature into the product C6H6+3H2. Note that, at 100% conversion of C6H12 reactant to C6H6+3H2 product, 1,180 kJ of heat are absorbed chemically per 0.4536 kg (1 pound) of the resulting product. Note for comparison purposes that the vaporization requirement for about 0.45 kg of C6H12 equals (3800.45=) about 170 kJ, or only about 14% of the required thermal input to create pressurized C6H6+3H2. [0225] 7. Exhaust the product from the endothermic reactor and cool the product down with the first heat exchanger to just above the temperature at which the C6H6 will be condense into a liquid. The molar heat capacity of H2 is 28.84 Joules per an increase in temperature of 1 K (mol K). The molar heat capacity of vaporous C6H12 is 105 J/(mol K). The molar heat capacity of C6H6 is 135 J/(mol K). Thus, the molar heat capacity of three mols of H2 plus one mol of vaporous C6H6 equals ((28.843)+135=) 221.52 J. That is, the reactant has (135/221.52=) 61% of the heat capacity of the product. Assuming a perfect heat exchange, that will require passing only about 61% of the product through the first heat exchanger to preheat the C6H12 vapor to the temperature of the endothermic catalytic reactor. [0226] 8. In a second heat exchanger, cool the 39% portion of C6H6+3H2 down with some process to just above the temperature at which the C6H6 will become a liquid. [0227] 9. Recombine the and streams of C6H6 vapor+3H2 gas. [0228] 10. Pass the relatively low temperature C6H6+3H2 product mixture through a fully-regenerating CCVC engine. [0229] 11. For the source heat, use the heat separated out in the second heat exchanger. If desired, supply additional source heat to the C6H6+3H2 mixture to superheat it. [0230] 12. After the C6H6 vapor and the H2 gas product mix is finally exhausted from the fully-regenerated CCVC engine, cool it down to the point where the C6H6 condenses, thus separating the product into liquid C6H6 and H2 gas. [0231] 13. If possible, use any remaining latent heat in the CCVC engine exhaust to further reduce the heat requirements of the CCVC engine, for example, to supply the heat to increase the temperature of the pressurized C6H12 liquid reactant to just below the temperature required for vaporizing it at the given pressure. [0232] 14. Based on the latent heat requirements of the proposed endothermic heat engine (the chemical storage heat requirements being only relevant to the exothermic half-cycle), such a fully-regenerated CCVC engine can be expected produce delivered thermal efficiencies well in excess of 50% or more.

A Rankin/Stirling Fully-Regenerating CCVC-Based Exothermic Semi-Open Half-Cycle Heat Engine

[0233] For a semi-open exothermic half-cycle, the primary purpose is to generate thermal energy to be used in a heat engine operating at maximum efficiency. Per U.S. Pat. No. 3,225,538, FIG. 1, at 1 atmosphere the conversion of C6H6+3H2 will occur at about 540 K (512 deg F.). That will produce, with negligible work in, 1,180 kJ of heat per 0.4536 kg (1 pound). In addition, in U.S. patent application Ser. No. 18/095,463, it is proposed that a small compressor and negligible work be applied to C6H6 vapor for a similar purpose as that proposed in step 4 above for the endothermic half-cycle engine. That is, it is proposed to supply much of the required heat of vaporization for the C6H6 by the condensation of higher-pressure C6H12. In other words, with such an approach, both the work in to produce heat at 540 K and the heat cost required are negligible compared to the fairly high temperature heat produced. Therefore: [0234] 1. It is proposed that this exothermic heat from the C6H12<=C6H6+3H2 half-cycle be generated where there is both a source of useful high grade heat and a source of H2 gas, as for example is being produced by the electrolysis of H20. [0235] 2. The C6H6 liquid be converted into pressurized vapor just above the temperature of condensation. [0236] 3. The C6H6 vapor be compressed to a slightly higher pressure. [0237] 4. Gaseous H2 produced at the site be compressed to the same pressure and temperature. [0238] 5. The pressurized, heated C6H6 vapor and the similarly pressurized and heated H2 then be mixed to form a chemically-balanced C6H6+3H2 mix. [0239] 6. The C6H6+3H2 mix be passed through a first heat exchanger, raising the mix to the temperature close to the working temperature of the catalytic reaction chamber. [0240] 7. The C6H6+3H2 mix then be heated to exactly the working temperature of the catalytic reaction chamber (for 1 atmosphere pressure, about 540 K). [0241] 8. The C6H6+3H2 mix be passed through the exothermic reactor at constant pressure and temperature and converted back into hot, pressurized C6H12 reactant vapor. [0242] 9. The hot, pressurized C6H12 reactant vapor may then be cooled in the first heat exchange to just above the temperature of condensation by helping to preheat the C6H6 heat exchanger. As noted above, assuming a 100% conversion back to C6H12 reactant, the latent heat in the reactant can ideally only supply about 61% of the thermal energy required to heat the C6H6+3H2 mix to the temperature of the reactor. Therefore, the remainder, or about 87 kJ/(mol K) will need to be supplied by another heat source, for example, the heat being exothermically released by the conversion of the product back into the reactant. For C6H6 at 1 atmosphere, that temperature is 353.2 K. Therefore, a temperature difference of (540-353.2=) about 187 K would require (18787=16.269 Kilojoules. 39% of that would equal (16.2690.39=) 6.345 KJ/mol. At STP, C6H6 (liquid) has a mass of 78.11 g/mol. 0.4536 kg (1 pound) of C6H6 would equal (453.6/78.11=) 5.807 mols, and the total heat required would thus equal (6.3455.807=) about 37 kJ. That leaves a delivered heat output of (1(37/1,180)=) 0.969 or 97% or 1,173 kJ remaining of the total exothermically-produced heat at about 540 K. [0243] 10. Note that a thermal carrier fluid such as H2 or He gas could be used to cool the exothermic catalytic reactor, then be superheated with solar energy. That superheated carrier fluid can then be used to power a fully-regenerating CCVC engine.

[0244] Since the overall efficiency of a heat engine is used to determine the thermal efficiency of any heat used in that engine, the recycled exothermic heat is being utilized at the overall thermal efficiency of its heat engine. It is expected that such a fully-regenerating CCVC-based exothermic semi-open half-cycle heat engine can produce delivered thermal efficiencies in the range of 50% or more.

[0245] Accordingly, the total thermal efficiencies of both the endothermic half-cycle fully-regenerated CCVC engine and the exothermic half-cycle fully-regenerated CCVC engine can be expected to generate delivered thermal efficiency in the range of 50% or more.