FR3059355B1 - INSTALLATION FOR THE PRODUCTION OF ELECTRIC ENERGY, MECHANICAL ENERGY AND / OR COLD - Google Patents

Abstract

The invention relates to an installation for producing electrical energy, mechanical energy and / or cold comprising a circuit in which an organic fluid circulates substantially reproducing a Rankine cycle, said circuit comprising an expansion machine, a condenser and means for vaporizing said fluid on a portion of said high pressure cycle circuit. According to the invention, said vaporization means are supplied with organic fluid in liquid form by at least one liquid transfer pump housed in a liquid reservoir.

Description

Installation for producing electrical energy, mechanical energy and / or cold 1. Field of the invention

The field of the invention is that of the production of energy, in particular from solar radiation.

More specifically, the invention relates to an installation for the production of electrical energy, mechanical energy and / or cold based on an organic Rankine cycle, also known by the acronym ORC (Organic Rankine Cycle). . The invention finds particular application in the local production of electrical energy, mechanical energy or cold, possibly combined, on the scale of an urban island or neighborhood, or a farm. It is aimed particularly at people in developing countries. 2. State of the art

There are known systems producing electrical energy from solar energy using a Rankine cycle, intended to provide high electrical power. These known power generation systems are equipped with solar mirrors and a concentrator, which carry the working fluid, in this case water, at high temperature, and a gas turbine.

A disadvantage of these known Rankine cycle systems is that they require significant maintenance.

Also known are systems for producing electrical energy based on an organic Rankine cycle, using solar collectors with superheated water circulation. These systems require the use of an intermediate heat exchanger-evaporator, which increases the costs and decreases the efficiency of these systems. They are generally used with screw regulators when the electric power produced is greater than 100 kW.

Photovoltaic systems directly producing electrical energy from solar radiation are also known.

To support the development of photovoltaics, more and more rare earths are being extracted, the basic material of photovoltaic modules. This has consequences for the environment: water pollution for samples and processes, greenhouse effect related to the high energy consumption required for the extraction of minerals and the manufacture of modules.

However, given the scarcity of materials used for the manufacture of photovoltaic cells, it is likely that we will witness in the coming years a rapid rise in the cost of photovoltaic modules.

Another disadvantage of photovoltaic technology is the recycling of photovoltaic panels at the end of their life.

On the other hand, in developing countries, theft of photovoltaic panels is very common because they are easy to steal and reuse.

On the other hand, thermodynamic systems using for example butane as gas are less often the target of looters. Indeed, the dismantling and reuse of the elements of these systems are more complex and present a danger. OBJECTIVES OF THE INVENTION The object of the invention is therefore in particular to overcome the disadvantages of the state of the art cited above.

More specifically, the invention aims to provide a facility for producing electrical energy, mechanical energy or cold that is inexpensive and of a suitable yield.

An object of the invention is notably, in at least one particular embodiment of the invention, to provide such an installation that makes it possible to produce electricity with a yield of at least 10%

Another object of the invention is to provide a technique for producing electrical energy, mechanical energy or cold that is simple to implement and easy to maintain. The invention also aims to provide a facility for producing electrical energy, mechanical energy or cold without impacting the greenhouse effect.

Yet another object of the invention is to provide an installation for the production of electrical energy, mechanical energy or cold which is difficult to dismantle for a thief, without taking any risk. 4. Presentation of the invention

These objectives, as well as others which will appear later, are achieved by means of an installation for producing electrical energy, mechanical energy and / or cold comprising a circuit in which an organic fluid circulates, substantially reproducing a Rankine cycle, said circuit comprising an expansion machine, a condenser and means for vaporizing said fluid on a portion of said high pressure cycle circuit.

According to the invention, said vaporization means are supplied with organic fluid in liquid form by at least one liquid transfer pump housed in a liquid reservoir.

Thus, in an unprecedented manner, the invention proposes to draw the liquefied organic fluid into a tank, which makes the installation particularly reliable.

It should be noted that the liquid transfer pump makes it possible both to circulate the liquid in the circuit and to bring the liquid organic fluid to the high pressure of the Rankine cycle.

According to an advantageous aspect of the invention, said organic fluid is n-butane or propane.

Preferably, said expansion machine is a positive displacement compressor belonging to the group comprising at least: spiro-orbital compressor; - piston compressor; - vane compressor; - centrifugal compressor; - screw compressor; said positive displacement compressor being used in expander mode.

In a particular embodiment of the invention, said liquid reservoir is formed in the lower part of a hermetic enclosure containing said expansion machine and said liquid transfer pump is connected to the output shaft of said machine. relaxation.

Advantageously, an installation for producing electrical energy, mechanical energy and / or cold as described above comprises at least one priming pump housed in a second liquid reservoir.

According to a particular aspect of the invention, an installation for producing electrical energy, mechanical energy and / or cold as described above comprises at least one liquid level balancing tube connecting said second storage tank. liquid to said tank in which is housed said liquid transfer pump, for maintaining the liquid levels in the second tank and the tank in which is housed said liquid transfer pump substantially at the same level.

Advantageously, said liquid transfer pump is an injection pump used in the automobile for injecting gasoline.

According to a particular embodiment of the invention, said liquid reservoir is a hermetic reservoir.

In at least one particular embodiment of the invention, said vaporization means comprise a plurality of solar collectors connected in parallel.

According to one particular aspect of the invention, said solar collectors are solar collectors with vacuum tubes.

Preferably, said sensors comprise a heat pipe for transporting the heat received by said vacuum tubes to a collector.

According to an advantageous aspect of the invention, the internal diameter of said manifold is less than 25 mm in order to limit the volume of butane.

In a particular embodiment of the invention, said expansion machine is coupled to an alternator supplying electric current when it is rotated.

According to a particular embodiment of the invention, an installation for producing electrical energy, mechanical energy and / or cold as described above comprises an evaporator, intended to cool a secondary fluid, such as brine or air, on a portion of said low cycle pressure circuit and a compressor is coupled to the output shaft of said expansion machine.

This gives an installation whose power consumption is substantially reduced, and up to more than 90%, compared to known refrigeration installations, and which is particularly suitable for air conditioning premises in summer.

The compressor secured to the expansion machine is advantageously a refrigeration compressor, such as a piston compressor, a spiro-orbital compressor, a screw compressor or a centrifugal compressor of a type known per se.

In a particular embodiment of the invention, an installation for producing electrical energy, mechanical energy and / or cold as described above comprises a cooling tower connected to said condenser, intended to evacuate in the air the heat extracted from the organic fluid at the level of said condenser. 5. List of Figures Other features and advantages of the invention will appear more clearly on reading the following description of four embodiments of the invention, given as simple illustrative and non-limiting examples, and the accompanying drawings. among which: • Figure 1 is a schematic representation of a first exemplary embodiment of an electric power generation installation according to the invention; FIG. 2 is a detailed view of one of the solar collectors of the installation according to the invention presented with reference to FIG. 1; FIG. 3 is a sectional view of the collector associated with the solar collector presented with reference to FIG. 2; FIG. 4 represents an example of a thermodynamic cycle carried out by n-butane in the circuit of the installation presented with reference to FIG. 1; FIG. 5 illustrates a second exemplary embodiment of an electrical energy production installation according to the invention, in which the pump is connected to the output shaft of the expansion machine; FIG. 6 is a diagrammatic representation of a third exemplary embodiment of an electrical energy production installation according to the invention, in which the heat at the condenser is evacuated by drilling water; FIG. 7 is a schematic representation of an exemplary embodiment of a cold production plant according to the invention; FIG. 8 is a schematic representation of an alternative embodiment of the cold production plant according to the invention presented with reference to FIG. 7. Detailed Description of the Invention 6.1. Example of embodiment of the invention

FIG. 1 shows a power generation installation according to the invention.

This installation comprises a set of n solar collectors la, lb, ... ln, connected in parallel, in which is vaporized butane in liquid form, distributed by a pipe 14 in the sensors la, lb, - ln.

The solar collectors 1a, 1b, 1n are vacuum tube collectors.

In variants of this particular embodiment of the invention, the solar collectors may be flat solar collectors, preferably double-glazed.

The high-pressure butane vapors collected at the outlet of the sensors 1a-1n are directed by the manifold 2 to the expansion machine 4. This is placed in a hermetic enclosure 3 and ensures the release of the injected vapors, while driving the In this particular embodiment of the invention, the expansion machine 4 is a spiro-orbital compressor used in the expander mode.

In variants of this particular embodiment of the invention, it may be envisaged to use a piston compressor, a vane compressor, a screw compressor, a centrifugal compressor, in expander mode, or any other displacement compressor. positive used in expander mode of known type.

The expanded steam is sent through the pipe 6 to a heat recovery exchanger 7, also called regenerator, which provides a first cooling of the vapors before sending them through the pipe 8 to the condenser 9, where the rest of the heat is removed, thus ensuring the transition to the liquid state of the working fluid.

It should be noted that the exchanger 7 makes it possible to increase the cycle efficiency by about 15%.

The liquid leaving the condenser 9 is directed through the pipe 10 into a low-pressure liquid reservoir 11 which stores the fluid. An integrated pump 12 draws the liquid into the bottom of the tank 11 and distributes it at high pressure through the pipe 13 in the exchanger 7, where the liquid will heat up before being injected again into the solar collectors 1a, 1b, - ln.

In variants of this particular embodiment of the invention, several liquid suction pumps, mounted in parallel in order to increase the flow rate and / or in series in order to increase the delivered pressure, can be integrated into the tank 11.

The reservoir 11 is advantageously equipped with a heat exchanger for cooling (not shown in FIG. 1) fed for example with water from a water table, intended to allow the temperature of the butane inside the tank 11 is the lowest of the entire circuit, so that the liquefied butane is fully stored in the tank 11 during shutdown periods of the installation. In this particular embodiment of the invention, the cooling exchanger is formed of a coil-wound tube outside the tank 11. In a variant of this particular embodiment of the invention, it can also be provided that the cooling exchanger is formed of a coiled-coil tube housed inside the liquid reservoir 11.

The pump 12 is advantageously an injection pump of the same model as that used in the automotive industry for supplying petrol to the engines of cars and comprises at the discharge a check valve (not shown).

The commissioning of the pump 12 is controlled when there is an overheating of the fluid inside one of the collectors 51 of the solar collectors 1a, 1b-1n, beyond the saturation temperature of the collector. -butane.

Several vertical probes 19 are buried in boreholes, in order to evacuate the heat extracted from the condenser 9 in the ground. For this purpose, a pump 18 circulates water in a closed circuit between the condenser 9 and the probes 19, through the pipes 16 and 17. The alternator 5 produces electric current thanks to the mechanical energy transmitted by the machine The current is transmitted to an electrical regulation assembly 15 comprising, inter alia, a rectifier, a regulator, current storage batteries and an inverter (not shown in detail in FIG. 1). The electrical energy is stored in the batteries and feeds the pump auxiliaries 12 and 18 and a distribution point U of the electrical production. All the equipment of the electrical energy production plant, with the exception of the solar collectors and the probes 19, are grouped together in an enclosure E for confining flammable liquids under pressure, placed outside, designed according to current safety standards.

Figure 2 illustrates the operation of one of the solar collectors la, lb, or ln vacuum tubes and heat pipe. The solar radiation is captured by a set of vacuum tubes 51i, 512 .... 51n each containing a heat pipe 50i, 502 .... 50n which transports the heat captured by the tubes to an evaporator manifold 54, where the liquid organic penetrating EL in the collector 54 vaporizes. The vaporized n-butane leaving the collector 54 at the point SG is collected with the one leaving the other solar collectors for supplying the expansion machine 4 with pressurized steam. In this particular embodiment of the invention, 40 m2 of solar collectors 1a, 1b, 1n are provided to produce 3 kW of electricity at the level of the alternator 5.

FIG. 3 is a sectional view of the collector 54 at the level of the last tube 5li on which it can be seen that the tube 50i is sealingly welded to the collector / exchanger 54. The heat pipe 53, of which only one end is shown on FIG. FIG. 3 is in direct conductive contact with the tube 50i in order to transfer heat from the vacuum tube 51i to the boiling organic liquid in the volume 52 of the collector 54. The latter has an inside diameter equal to 20 mm and is insulated on the outside to prevent heat loss.

FIG. 4 illustrates a thermodynamic cycle carried out by n-butane during its circulation in the installation. The vapors of n-butane superheated at 130 ° C. at high pressure (point F) are admitted into the expansion machine 4, from where they exit at low pressure (point G). The vapors are then cooled to 56 ° C in the exchanger 7 (point H) before entering the condenser 9. The formed liquid (point I) is sucked by the pump 2 which sends it at high pressure (point J) in the exchanger 7 from where the liquid comes out heated to 80 ° C (K point) before being distributed in the solar collectors la-ln. In these, the liquid n-butane is vaporized by the solar radiation captured to emerge as vapor (point F) and carry out a new cycle. 6.2. Other examples of embodiment of the invention

FIG. 5 illustrates another exemplary embodiment of an electrical energy production installation according to the invention having the same shaft, the same expansion machine 4, the same alternator 5 and the same main liquid pump 21 as in FIG. the previous example. Advantageously, the shaft, the expansion machine, the alternator and the main pump are housed in a hermetic enclosure 20.

In a variant of this particular embodiment of the invention, this enclosure may be semi-hermetic and made in two parts assembled with flanges bolted together and a seal. In yet another variant, the shaft, the expansion machine, the alternator and the main pump may not be housed in an enclosure.

A partition 33 with a seal (not shown in FIG. 5) separates the upper part of the enclosure 20, where the fluid is gaseous, and the lower part of the enclosure, which contains the pump 21 and a reserve of n-butane in liquid form. Above the partition 33, the mechanical parts of the upper part of the enclosure 20 are immersed in lubricating oil, the level of which is seen to be corrugated in FIG. 5,

The n-butane liquid leaving the condenser 9 by the pipe 23 is directed mainly in the pipe 25, to the lower part of the enclosure 20. The pump 21 sucks the liquid in the bottom of the lower part of the enclosure and the It can be seen in FIG. 5 that the pump 21 is connected to the output shaft of the expansion machine 4, which provides it with the mechanical energy necessary for its operation, without the need for a pump. it is necessary to provide an electric motor to operate the pump 21.

A thermostatic control valve 27, preferably with external pressure equalization, is provided to limit the quantity of liquid n-butane sent via the pipe 31 to the exchanger 7, then to the solar collectors 1a, 1b, ... 1n , when an overheating of the vapors leaving the solar collectors occurs, and thus avoid liquid returns to the expansion machine 4. The control valve 27 is a pressure equalization valve 28 and is equipped with a thermostatic bulb 30 connected to it by a balancing tube 29. In a variant of this particular embodiment of the invention, it may also be envisaged that the valve is motorized and controlled by temperature and pressure probes.

The residual fraction of liquid leaving the condenser 9 is directed, via a second pipe 24, to the reservoir 11, whose liquid level equilibrates with that of the lower reservoir of the group 20, thanks to level balancing tubes ( not shown in Figure 5) connecting the two tanks. An auxiliary pump 12 makes it possible to inject, via the pipework 32, liquid from the tank 11 into the exchanger 7, placed upstream of the solar collectors 1a, 1b-1n. The auxiliary pump 12 makes it possible to initiate the circulation of the organic fluid in the installation after a shutdown of the installation following a period of absence of sun. It overcomes the pump 21, which needs to operate that the expansion machine 4 is fed with n-butane vapor, and is therefore stopped after a period without sun.

FIG. 6 illustrates another exemplary embodiment of an electrical energy production installation according to the invention.

In this particular embodiment of the invention, the n-butane circuit and its equipment are identical to those of the electrical energy production installation presented with reference to FIG.

As can be seen in FIG. 6, the pump 36 draws water into the cooling tank 43 and delivers it to the condenser 9 via the pipe 35. The heated water leaving the condenser 9 is then conveyed by a pipe 37 to a spray boom 40 within the cooling tower 39. At the ramp 40, nozzles 41 can spray the flow of water on a block 42 with a large honeycomb surface while allowing the passage of air by thermal draft. The cooling air enters the lower part AE of the cooling tower 39, passes through the block 42 and is evacuated naturally by the opening AS, in the upper part of the cooling tower 39. Moreover, a part of the water poured on the surface of the block 42 evaporates and humidifies the air leaving through the opening AS of the cooling tower 39.

The basin 43 is supplied with water by a submerged pump 46, which draws water into a water table 47 and delivers it through the pipe 45. The water level of the basin 43 is regulated by means of a float control system 48 which puts into operation or controls the stopping of the pump 46. It should be noted that this makes it possible to divide by twenty the quantity of water necessary for the cooling of the condenser, with respect to a solution in lost water.

FIG. 7 illustrates an exemplary embodiment of a cold production installation according to the invention.

This installation has a hermetic enclosure 60 containing an expansion machine 62 and a compressor 67, each at the end of a shaft 63.

The vaporized and high-pressure working fluid of the cycle leaving the first evaporator 84 via the conduit 83 enters the expansion machine 62 through the tube 61. It expands in the expansion machine 62 to an intermediate pressure, which results in the shaft 63 rotates and operates the compressor 67, and is rejected in the volume 64. The lubricating oil 65 of the expansion machine 62 is stored in the lower part of the volume 64 above the partition 66, which separates the inner volumes 64 and 72 of the enclosure 60. A groove on the shaft 63 allows the oil 65 to rise to the expansion machine 62.

The compressor 67 draws the low pressure vapors from the working fluid cycle in the upper part of the volume 72 and delivers them to the intermediate pressure of the cycle in the volume 64 via the pipe 71.

It will be noted that the low-pressure vapors of the cycle are introduced into the volume 72 of the chamber 60 through the low-pressure inlet 73 and guided to the upper part of the volume 72 in an inner tube 68.

This tube advantageously has in the lower part an orifice in contact with the oil 69 situated in the lower part of the volume 72. Thanks to this orifice, oil is sucked up with the flow of oil in the tube 68 and discharged at the top. volume 72 on the compressor, which ensures its lubrication. The lubrication of the compressor 67 is completed by the oil of the supply 65 which is driven along the shaft 63 through the partition 66 to the moving mechanical parts of the compressor.

The intermediate pressure vapors exit through the outlet 70 and are sent into the heat exchanger, or regenerator, 76 and then to the condenser 78 via the piping 75.

The condenser 78 may be an organic fluid / air or organic fluid / water heat exchanger, where air, or water, enters the condenser 78 through the inlet ER and exits through the outlet SR. The liquefied intermediate pressure working fluid in the condenser 78 flows through line 79 into the liquid reservoir 80.

An integrated pump 81 draws a portion of the working fluid in liquid form into the bottom of the tank 80 and distributes it at high pressure through the pipe 77 in the heat exchanger, or regenerator 76, where the liquid working fluid is heated, then enters the evaporator 84.

In variants of this particular embodiment of the invention, several liquid suction pumps, mounted in parallel in order to increase the flow rate and / or in series in order to increase the delivered pressure, can be integrated into the reservoir 80.

The reservoir 80 is advantageously equipped with an internal heat exchanger intended to cool the reservoir 80 (not shown in FIG. 8), fed by the cooling circuit of the condenser 78, whose function is that the temperature of the reservoir 80 is the lower of the entire circuit, so that the liquefied butane is fully stored in the tank 80 during shutdown periods of the installation.

The pump 81 is advantageously an injection pump of the same model as that used in the automotive industry to supply fuel to the engines of cars and comprises at the discharge a check valve (not shown in Figure 7). It is electrically powered by the AP power supply.

The commissioning of the pump 81 is controlled when there is an overheating of the fluid inside the conduit 83. The evaporator 84 is in this particular embodiment of the invention formed of a plurality of solar collectors. mounted in parallel.

In variants of this particular embodiment of the invention, it may also be envisaged that the evaporator 84 is a plate heat exchanger fed with a hot fluid at EC and outgoing at SC.

To ensure the production of cold, a portion of the liquid contained in the tank 80 is sent through the pipe 86 to the expander 87 which will release it from the intermediate pressure to the low pressure of the cycle. The expanded liquid is sent through the pipe 88 into the refrigeration evaporator 89, where it vaporizes by cooling the external fluid to be cooled, which enters through the EEV inlet into the evaporator 89 and exits through the outlet SEV. At the outlet of the refrigerating evaporator 89, the working fluid vaporized at low pressure of the cycle is directed in the pipe 85 to the inlet 73 of the group 60.

In Figure 8, there is shown a variant of the cold production plant shown in Figure 7.

As can be seen in FIG. 8, a pump 90 is mounted on the shaft 63 between the expansion machine 62 and the compressor 67, in the hermetic enclosure 98 of the cold production plant. The shaft 63 thus drives the moving parts of this pump, which ensures its operation without using electricity. The pump 90 draws liquefied organic fluid into the liquid reservoir 93 via a pipe opening on the connection 92. At the outlet 91 of the pump 90, the liquid is sent through the tube 95 to the circuit portion 97 connected to the heat exchanger, or regenerator, 76.

A priming pump 94 of the installation is also immersed in the liquid reservoir 93. This pump 94 is mounted so as to inject liquid into the tube 97, via the tubing 96. Check valves (not shown in Figure 8) allow the pumps 90 and 94 to operate independently.

The reservoir 93 is advantageously equipped with an external heat exchanger for cooling the reservoir 93 (not shown), whose role is that the temperature of the reservoir 93 is the lowest of the entire circuit, so that the liquefied butane either entirely stored in the tank 93 during periods of stopping the installation.

Claims (12)

1. Installation for producing electrical energy, mechanical energy and / or cold comprising a circuit in which an organic fluid circulates substantially reproducing a Rankine cycle, said circuit comprising an expansion machine (4; 62), a condenser (9) and means for vaporizing said fluid on a portion of said high-pressure cycle circuit, said vaporizing means being supplied with organic fluid in liquid form by at least one liquid transfer pump (12; 21; 81) accommodated in a liquid reservoir (11; 80), characterized in that said liquid transfer pump (21) is connected to the output shaft of said expansion machine (4) and in that said installation comprises at least one priming pump (12) housed in a second liquid reservoir (11). 2. Installation according to claim 1, characterized in that said organic fluid is n-butane or propane. 3. Installation according to any one of claims 1 and 2, characterized in that said expansion machine (4; 62) is a positive displacement compressor belonging to the group comprising at least: - spiro-orbital compressor; - piston compressor; - vane compressor; - centrifugal compressor; - screw compressor; and in that said positive displacement compressor is used in expander mode. 4. Installation according to any one of claims 1 to 3, characterized in that said liquid reservoir in which is housed the liquid transfer pump (12; 21; 81) is formed in the lower part of a hermetic enclosure containing said triggering machine (4; 62). 5. Installation according to claim 1, characterized in that it comprises at least one liquid level balancing tube connecting said second liquid reservoir (11) to said tank in which is housed said liquid transfer pump (21) , to maintain the liquid levels in the second tank (11) and the tank in which is housed said liquid transfer pump (21) substantially at the same level. 6. Installation according to any one of claims 1 to 5, characterized in that said reservoir (11; 80; 93) is a hermetic container. 7. Installation according to any one of claims 1 to 6, characterized in that said liquid transfer pump (12; 21; 81) is constituted by at least one injection pump used in the automobile for injecting fuel. petrol. 8. Installation according to any one of claims 1 to 7, characterized in that said means for vaporization comprises a plurality of solar collectors (la; lb,. ~ Ln) connected in parallel. 9. Installation according to claim 8, characterized in that said solar collectors are vacuum tube solar collectors (51i, 512 .... 51n). 10. Installation according to any one of claims 1 to 9, characterized in that said expansion machine (4) is coupled to an alternator (5) providing electric current when it is rotated. 11. Installation according to any one of claims 1 to 9, characterized in that it comprises an evaporator (89) for cooling a secondary fluid, such as brine or air, on a portion said low cycle pressure circuit and that a compressor (67) is coupled to the output shaft of said expansion machine (62). 12. Installation according to any one of claims 1 to 11, characterized in that it comprises a cooling tower (39) connected to said condenser (9) for discharging in Peer the heat extracted from the organic fluid at said condenser ( 9).