DE2164224A1 - Heat engine - Google Patents

Description

Pete nte

D! Pi.-Sn-. ^r ". ""." 7Z serw

ünc ^ na, Slsinsdorfstr. IQ 216422t ¹

65-18.O69P (18.O7OH) December 23, 1971

Thermo Electron Corporation, Waltham (Mass.)

V. St. A.

Heat power tmas chine

Operation of a usual, according to the Stirling cycle working heat engine is basically based on the fact that a given amount of gas at low temperature contracts and compresses and expands at high temperature. Generally one uses one Displacement piston to move the working gas between a zone of certain high temperature and a zone of certain lower Move the temperature back and forth. The gas is heated in the hot zone, and as it expands and in the cold zone flows, it actuates a working piston. As it flows over into the cold zone, the gas gives off a large amount of heat to a heat store. In the cold Zone contracts the gas j and it becomes when the working piston reverses its stroke, condenses. Since the

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seal at colder temperature than the expansion takes place- ' finds, there is a surplus of work,

Many modifications of the Stirling engine have already been developed, but this has never found widespread use, mainly because of the extremely high working temperatures, those necessary for reasonable, labor yield are"

In the invention, a modified Stirling cycle is used used and the gas replaced by a condensable working medium. The arrangement of a floodable heat storage in the machine enables effective Use of the condensable vapor «So in a certain sense the invention can be seen as an embodiment of a Rankine cycle machine which is modified to include both vapor and liquid heat storage and has neither mechanical control nor feed pump. A working piston opens in one of the cylinders, a displacement piston opens in another of the cylinders and low, and a floodable heat accumulator is arranged in the third cylinder. Above · the heat accumulator is an evaporator, to which heat is supplied, and under the heat accumulator there is a condenser, from which heat is extracted, arranged. Inside the liquid heat storage, heat is stored by means of a bed of heat-storing Bodies far enough apart that no capillary action occurs. The steam heat storage resembles the gas heat storage of a Stirling engine. The condenser is in communication with the one in the displacement piston cylinder below the displacement piston

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sensitive so-called cold zone. The evaporator is - preferably by means of a superheater - with the one located in the displacement piston cylinder above the displacement piston
Hot zone connected. The hot zone is in the manifold connecting the three cylinders, and this manifold may contain a superheater.

The floodable heat storage is a key part of the machine; it can consist of a bed of heat-storing bodies contained in the cylinder, through which the working fluid flows. ' In the bed, the level of the liquid phase of the working medium is controlled by the position of the displacement piston. Each level of the bed has its characteristic, essentially constant temperature, and if the pressure in the system is higher than the saturation pressure of the working medium, which one is the one
the given mirror height corresponds to the corresponding temperature,
then the working medium will precipitate on the liquid surface until the pressure of the system is equal to the saturation pressure. If the system pressure is lower than the saturation pressure at a given pressure-temperature level, then liquid will evaporate at this level until the system pressure equals the saturation pressure
is. The floodable heat accumulator can store or give off heat, and useful work can be taken from the working piston, as this is actuated by the large difference between the evaporator pressure and the condenser pressure compared to the hot-air machine such as the Stirling machine.

The sequence of operations in the machine

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becomes understandable if one assumes the displacement piston be in such a position that the level of the liquid. Work equipment in the heat accumulator - which one could also call flood level - near the lower end, d. H. near the condenser, so it's near the cold end. The displacer is at this time at the top of his Cylinder, and the working piston begins its return stroke to the top of his cylinder. The pressure in the system corresponds the relatively low saturation temperature of the capacitor «The working piston moves against only low pressure to the top of its cylinder to complete its return stroke Moving at the bottom of its cylinder, the liquid rises through the floodable heat accumulator to the evaporator at the top of the heat storage tank (d <> do the hot zone). The pressure in the system is now that of the evaporator temperature associated saturation pressure. The difference between the evaporator pressure and the condenser pressure is very large compared to a gas circuit with the same upper and lower limit temperature. The working piston begins then its downward stroke, the working stroke. The expansion work of the working piston during its working stroke is much greater than its compression work. -> ;. Finally, after the working stroke, the displacement piston is moved to the upper end of its cylinder, and so is the liquid level falls from the evaporator to the condenser. Then the system is returned to the state that passed at the beginning of the cycle.

The particular advantages of this steam cycle machine are:

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1) the Fähigkeit-, large DruckuntexschiBd at xuxx · moderate Temperaturuntersehied to erreie'hem,

2) (the lack of mechanical steering magnet.,

3) the! Lack of feed pumps,

4) quiet operation,

5) convenient way to mii the machine; a hydraulic To couple load,

6) Liquid and vapor heat storage, and

7) Suitability for many types of work equipment (including mixed work equipment).

For understanding, reference is made to the drawing, in which several exemplary embodiments of the invention are shown are. Show it;

Fig. 1 is an independent schematic outline of a machine with its main component;

Figures 2A-2F are schematic sketches of the same machine in different operating positions;

3 shows an idealized temperature-entropy diagram the machine with floodable heat storage;

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4-6 sketches of other embodiments of the invention Machine with floodable heat storage.

TPIg, 1 shows three parallel cylinders, a cylinder 12 containing the floodable heat accumulator, a displacement piston cylinder 14 and a working piston cylinder 16, the upper ends of which are connected to one another by a manifold. Within the cylinder 12, a bed of heat storage bodies 20, e.g. B. from metal balls, held distributed over the entire height of the cylinder 12 by means of support plates made of wire mesh.

Inside the cylinder 14 is located, through the outside applied force up and down movable, a displacement piston 22 on a piston rod 24, which through the bottom wall of the cylinder 14 passes through. The displacement piston fulfills the double function of displacing the liquid and the steam-filled and the liquid-filled Separate areas of the machine from each other thermally. The piston rod is surrounded by a seal, which allows their leak-free back and forth movement. The cylinder 16 can be moved up and down in a similar manner a working piston 26 with piston rod 25, which transmits the work, is arranged.

In the cylinder 12 containing the flood heat exchanger there is a condenser 30 at the bottom and an evaporator 32 at the top. As indicated by the symbols "Q" and ¹¹ Q ", heat is introduced into the evaporator 32.

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out and discharged from the condenser 30. Demented. accordingly arises over the length of the cylinder 12-out. a temperature gradient. In the cylinder there is a working fluid, e.g. B. simply water or better a liquid mixture such as ammonia-water or trichloroethyl alcohol-water; the flood level (liquid level) is indicated at *} K. Above this liquid level there is the liquid in vapor form, as explained in detail below.

Above the evaporator 32, in the distributor pipe 18, steam-generating bodies 36 can be arranged, which consist of loosely stacked or wound thin metal wire or other material and have a large surface area and high longitudinal conductivity. So that these bodies do not migrate away, bushings with a narrow bore can be provided, which form the superheater 38 in the distributor pipe 18; and they can be kept separated from evaporator 32 by any suitable barrier that does not obstruct the passage of vapor.

Above is the temperature gradient in the floodable Heat storage cylinder 12 and the fact that each mirror height in the cylinder 12 has a characteristic, has a substantially constant temperature. When the piston 22 is moved downward, the liquid level becomes 3 ^ lifted through the heat storage cylinder 12 - in borderline cases up to the evaporator - and the heat-storing bed is heated. The system pressure is now balanced the saturation pressure associated with the evaporator temperature, In the other borderline case, when the piston 22 is raised,

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the mirror 3 ^ above the height of the heat storage cylinder lowered and its heat-storing bed cooled to the low temperature of the condenser 30.

Simultaneously with the rise of the displacement piston 22, the working piston 26 rises to the upper end of its Cylinder, which because the system pressure is low, only low compression work, and that from the working cylinder 16 and the distributor pipe 18 expelled steam flows through the heat storage cylinder 12 and is for the most part depressed in it. Of course, when the liquid level is in the condenser 30, the low system pressure of the saturation temperature of the capacitor.

The order of the workflow is maybe can be seen more clearly from FIGS. 2A-2E. The thermodynamic Gear of the heat engine with submersible Heat storage is shown in Fig. 3 in the temperature-entropy diagram shown in relation to the positions of the pistons. The somewhat modified type shown in FIG. 2A the machine is thermodynamically equivalent to the type shown in FIG. About mechanical simplicity sake are the combined functions of the displacement piston shown in Fig. 1, namely the working fluid displace and separate the vapor and the liquid from each other, in Fig. -2 on the displacement piston and the Dividing piston distributed.

Fig. 2 A shows the position of the displacement piston 22, the separating piston 9k and the working piston 26 at the end of the

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Return stroke. The displacer is at the bottom of his Stroke, and the working piston 26 is at the top of its stroke, and the working piston 26 is at the top of its Hubes. In all cases the movement of the separating piston is 9 ^ with that of the working piston 26 is hydraulically coupled. The flood level is located in the capacitor 30 "and the The low pressure of the system corresponds to the saturation temperature of the compressor 30 · The conditions correspond to State point A in Fig. 3

Fig. 2 B shows the beginning of the working stroke by the movement of the displacement piston 22 is initiated to its top dead center. This movement of the displacer piston the liquid level is raised from the condenser 30 to the cooker (or evaporator) 32. Now that's the whole The system pressure fulfilling the machine is the saturation pressure associated with the temperature of the digester 32. This state is represented by point B in FIG.

because

dP >. dP

dT (saturated steam) ^ dT (gas)

is the difference between the highest pressure corresponding to the digester temperature and that of the condenser temperature corresponding lowest pressure large in relation to the comparable pressure difference with a gas machine working as work equipment; because with this the difference in gas pressures is inevitably due to the Relation of the absolute inlet and outlet temperatures is limited.

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Fig. 2 C shows the machine during the working stroke, while work is being taken from the working piston. There the working flask and the separating flask move together, so boiling, evaporation and overheating take place at the same time (as shown in Fig. 3 by line C).

The end of the working stroke is shown in Fig. 2 D * The associated state point D is indicated in FIG. 3.

The piston position at the beginning of the return stroke is shown in FIG. The corresponding state point is in Fig. 3 indicated. This step is initiated by the displacement piston and, accordingly, the liquid level go to their lowest position. The system pressure then goes down to its lowest value · During the pressure decrease with constant volume, the working fluid describes the thermodynamic path D-E.

Fig. 2 F shows the return stroke - the compression stroke of the working piston 26; it shows how the piston draws the steam pushes out of the separating cylinder, whereby it needs to do very little work against the low system pressure. This condensation process - it is shown in FIG. 3 by the Line F shown - is ended in Fig. 2A; so begins the cycle all over again.

In Fig. H - 6 different types of machine with a floodable heat storage are shown. These can be roughly divided into two classes: firstly, machines with double-loaded pistons and secondly, machines with displacement pistons. Fig. H shows a machine with

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double loaded piston, in which the upper side of the evaporator 32 is only connected to the working piston cylinder 16 and the condenser 30 is connected to a second working piston cylinder 16A. The floodable heat accumulator 12 is located between the evaporator and the condenser. Both working pistons are articulated to a common crankshaft as in a Stirling engine of the ^w Alpha ^{n design} , as defined by Rider.

In Fig. 5, a machine with a displacement piston is shown. In this example, the displacement piston 22 and the working piston 26 work in one and the same cylinder; the evaporator 32 is with the cylinder 16 above of the displacer 22, and the condenser 30 is connected to the same cylinder below the displacement piston but above the working piston 26. The work delivery and the timing of the Pistons are completely similar to those of the "Beta" -type of the Stirling engine.

In FIG. 6, separate cylinders are provided for the displacement piston 22 and the working piston 26, and the evaporator 32 is connected only to the displacement piston cylinders. Here the workload and timing are like the "Gamma" design of the Stirling engine, as defined by Robertson. Both in Fig. K and in Fig. 5, the displacement piston 22 must follow the working piston 26 during the stroke, so that the liquid level in the floodable heat accumulator (and thus the system pressure) is maintained.

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Flg. Figure 7 shows a practical embodiment of the invention which combines mechanical simplicity and good efficiency in operation. There another type of floodable heat accumulator is provided, which has a liquid heat accumulator 72, which contains tubes of relatively small inner diameter, thin wall thickness and low thermal conductivity and is arranged between a cooker or evaporator lh and a condenser 76 - Storage 76, so that the heat losses remain very small, have such properties and such design as mentioned above,

A certain amount of metal wool or similar material is packed into the tube? 2 containing the liquid heat accumulator in order to increase the cooling and heating of the working medium flowing through the heat accumulator, as explained in greater detail below. A certain number of soldered balls can be arranged inside the cooker lh- in order to enlarge the hot surface, so that the evaporation of the working medium is improved. The condenser 76 may contain a similar amount of soldered balls 82 that similarly increase the condensation of the vapor.

At its top, the cooker is connected to a U-shaped steam heat store 84, which has a certain Amount of a substance with a large surface area and low longitudinal conductivity such as e.g. B. loosely wound thin Includes wire 86. The purpose of the wire is to conserve heat by removing some of the steam overheat warmth from previous circulatory games

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--13 -

for use in a given circuit game, which will be discussed in more detail below. At the right end of the steam heat accumulator 84 there is a superheater 88, which also has soldered balls for improving the circulatory efficiency by overheating the
May contain steam.

A generally dumbbell-shaped separating piston cylinder is connected to the superheater. Its upper end
forms a cylinder 89 with a relatively large inner diameter, on the upper end wall of which a steam bellows 90 is attached in a steam-tight manner. Inside this
Steam bellows 90 is connected to superheater 88; but the rest of the interior of the cylinder with a large inner diameter
is separated from the superheater by the bellows 90. 'The cylinder 89 of large inner diameter is connected to a coaxial cylinder 92 of smaller inner diameter,
within which a piston 9h goes up and down, which forms a thermal barrier. The movement of this separating piston 9 ^ is coupled to that of the end of the bellows 90 by a separating liquid 95 which fills the cylinder 89 and the upper part of the cylinder 92 and has a low vapor pressure and good thermal stability. This liquid also provides the pressure equalization for the bellows 90 and thereby increases its service life and operational reliability.

Attached to the lower end of the small diameter cylinder 92 is a second large inner diameter cylinder 96. In this cylinder 96 is a bellows
98 fastened leak-tight, and between these bellows 98 and

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A second amount of separating liquid 99 is arranged on the piston 9h and fulfills a similar task to the separating liquid 95. Typically, liquids 95 and 99 will be of the same type and composition.

Below the bellows 98, a pressure equalization line 100 connects the lower part of the cylinder 96 with a cylinder 102 in which a displacement membrane is fastened in a leak-tight manner. A two-position magnetic coil 106 is fastened to this displacer membrane 1 Ok in its center by means of a rod 108. The movement of this two-position solenoid can be electrically controlled by an electronic switching device 112. Working fluid in the heat storage area is visible above membrane 104. Thanks to the use of bellows and diaphragm instead of sliding pistons, gap losses are avoided. Such gap losses are particularly difficult with small machines.

At the lower end of the cylinder 98 is a hydraulic line 114 connected; it is an example of how the work of the machine can be carried out. This line can be connected to any suitable consumer or any hydraulically operated device will. Other types of work derivation are conceivable, but the drawn system has properties that particularly recommend it, e.g. B. the that this coupling is free of Leaks is.

The electronic switching device 112 can be a conventional solid state circuit that continuously impulses current to the

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Solenoid 106 there. This magnetic coil 106 in turn acts on the displacement membrane 104 in such a way that the level of the liquid working medium is moved up and down between the condenser and the cooker lh. The pressure equalization line 100 causes rough pressure equalization within the system with the exception of the relatively small pressure differences that result from the small inertia forces of the flowing liquid the lowest possible energy consumption. The two-position solenoid can be provided with a locking latch or with a permanent magnet that holds it in the position it occupies without any effort. Most heat engines use a flywheel and some kind of gear to convert reciprocating motion into rotary motion to establish the stroke and change of direction of the piston; Such designs are also suitable for the machine according to the invention with a floodable heat accumulator, but the electronic design is cheaper and is mainly possible because only a small amount of working fluid needs to be displaced in the pressure-balanced system. The number of vibrations of the machine can be easily changed with the electronic control.

The operation of the machine shown in FIG. 6 is similar to that described above for somewhat simpler types. The electronic control unit 112 delivers as planned Current surges that actuate the solenoid 106, which the

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Enclosed membrane 104 upwards or downwards. The membrane is preferably made of sheet metal or rubber, and its diameter and its stroke in the relatively wide cylinder are large enough to move the flood level from one end of the relatively small cylinder 72, which contains the floodable heat accumulator, to its other end or - in other words - from the digester or compressor 7 ^ · to the condenser 16 and vice versa.

Heat is of course supplied in the evaporator 7k and in the superheater 88 and removed from the condenser 76, thus creating a circuit of the drive means in which the highest and lowest pressure alternate with the resulting deflection of the bellows 90 and the back and forth movement of the heat separating piston 9 ^ is generated. This reciprocating motion is transmitted through the bellows 98 to the hydraulic line 114 for useful work.

Other embodiments of the floodable heat storage than those described are possible. The work equipment can also be any one of numerous substances or Be composed of mixtures of substances. For example delivers a mixture of $ 61 ammonia and $ 39 water better Efficiency than water alone. Various metals or organic compounds are also suitable. In some In some cases, work equipment can also be used in the supercritical area for the sake of better efficiency.

Although direct mechanical coupling to the working piston may be useful, * is hydraulic coupling for many applications of submersible heat

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memory working machine cheap. For example, the machine with floodable heat storage would be particularly suitable be for

1) circulating hot water through a diving suit,

2) underwater propulsion (by screw or nozzle),

3) power supply of hydraulic tools under water, k) power plants,

5) implantable devices to support the circulatory system,

6) remote controlled pumping equipment,

7) Propulsion for land vehicles.

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Claims (8)

Claims / 1 .j heat engine, thereby geke η η ζ e i »η e tr that a condensable steam serves as a working medium in a closed system, which is a floodable heat storage (12), which forms part of this system, also a device that generates a temperature gradient across the heat accumulator, then a device which alternately sets the level of the liquid phase of the working medium in the floodable heat exchanger at the point of highest temperature and at the point of lowest temperature, the pressure in the closed system being relatively high at high temperature and at low temperature is relatively low, and contains a device which is connected to the closed system and is dependent on changes in the system pressure and converts these pressure changes into mechanical work. 2. Heat engine according to claim 1, characterized in that an evaporator (32, 7 * 0 »d ^em heat is supplied in the closed system, and a condenser (30, 76), from which heat is dissipated, at the top or at the the lower end of the floodable heat accumulator (12) are arranged, which generate the heat gradient across the heat accumulator, and a control device (106, 112) is arranged which alternately raises the level of the liquid phase of the working medium substantially towards the evaporator and substantially lowers it towards the condenser, · Where the pressure im 209833/0631 closed system then when the liquid level is in the evaporator, relatively high and then, when the liquid level in the condenser is relatively low, 3. Wärmekra.f tmaschine according to claim 1, characterized in that the pressure in the machine ^{fluctuates with the level of the '1} liquid phase of the working medium » H. Heat engine according to Claim 1, characterized in that the device which raises or lowers the level of the liquid phase of the working medium to the point of high or low temperature is a displacement piston cylinder (22), the piston of which moves in the cylinder and displaces the working fluid, and contains a device which actuates the displacement piston in such a way that it forces the working fluid through the machine. 5. Heat engine according to claim 4, characterized in that that the device actuating the displacer piston a device (112) which gives electrical impulses, and an electromechanical transducer (106) which responds to these impulses and with the displacement piston connected is. 6. Heat engine according to claim 1, characterized in that the device which is connected to the closed System connected and dependent on changes in system pressure is and this pressure changes in mechanical work 209833/0631 converts, contains a working piston cylinder (16, 16a) and moving piston (26) therein, which is moved in one direction by the relatively high pressure of the system and back in the other direction by the relatively low system pressure « 7. Heat engine according to claim 1, characterized in that that the working medium consists of a mixture of different Liquids consists " 8. Heat engine according to claim 1, characterized in that the device which the level of the liquid Alternate phase of work equipment to higher positions or lower temperature, raises or lowers a separating cylinder with a separating piston (9 ^) that can move back and forth in it and a displacement piston cylinder with a displacement piston (22) movable to and fro therein, and that the device, which, depending on changes in the system pressure, converts these pressure changes into mechanical work, a working piston cylinder with a working piston (i6, i6a) movable to and fro therein, furthermore a device, which hydraulically couples the working piston with the separating piston, so that the working piston and the separating piston are mutually exclusive move together, further a device which moves the displacement piston in the direction that this the level of the working fluid to a point higher Temperature and high pressure raises, with this pressure the separating piston and the working piston out of their original Positions in their cylinders moved in one direction, which releases work from the working piston, and one 209833/0631 Has device which the displacer in the moves opposite direction, so that this moves the level of the working fluid to a point of low temperature and low pressure moves, wherein the separating piston and the working piston are in their cylinders in the move in the opposite direction towards the low pressure and resume their original positions « 209833/0631 Empty page