ES2961828T3 - Cold and electricity production system from a low temperature thermal source, which allows adjusting the relationship between cold production and electricity production - Google Patents

Abstract

Cold and electricity production system from a low temperature thermal source, which allows adjusting the relationship between cold production and electrical production. Cold and electrical energy production system that comprises: - a desorber, called a generator (1), - a condenser (2), - an evaporator (3), - an absorber (4), - an absorbent fluid circuit. (100) in which a working fluid that comprises a refrigerant and an absorbent circulates, the fluidic circuit (100) that connects the generator (1) to the condenser (2), the condenser (2) to the evaporator (3), the evaporator (3) to the damper (4) and from the damper (4) to the generator (1), - a supersonic turbine (5) arranged in the fluid circuit (100) between the generator (1) and the damper (4) without pass through the condenser (2) and the evaporator (3), the turbine being configured to operate an electrical generator to produce electricity, - at least one ejector (50) arranged in the fluidic circuit between the generator and the turbine. (Automatic translation with Google Translate, without legal value)

Description

DESCRIPTION

Cold and electricity production system from a low temperature thermal source, which allows adjusting the relationship between cold production and electricity production

Technical field

The present invention relates to the field of thermodynamic systems for the co-production of electrical energy and thermal energy, more particularly cold energy, from a low temperature thermal source.

The applications of the invention are numerous, among which we can mention the field of stationary systems, with thermal sources such as thermal discharges from industrial processes, solar thermal, biomass, geothermal, gas turbines.

Previous technique

Current energy policies pose the problem of managing the fluctuation or intermittency of sources, but also of controlling the variability of energy demand peaks, while valuing low thermal level heat sources, typically 80 to 150°C. , such as solar thermal energy, abundant waste heat but low exergetic content.

In addition, special attention must be paid to the production of cold and electricity, stationary energy demands that grow rapidly and are usually responsible for high greenhouse gas emissions, particularly during demand peaks.

This problem is particularly significant for the mobility sector since it is responsible for a large part of the energy consumption and greenhouse gas emissions from both the propulsion itself and the on-board (cold) systems.

In fact, to satisfy these needs, the functional specifications of the systems that the inventors have formulated can be summarized as follows:

A/ be able to generate cold from a low temperature heat source, possibly fluctuating or even intermittent;

B/ be able to produce electricity from a low temperature heat source, possibly fluctuating or even intermittent;

C/ being able to simultaneously produce cold and electricity from a low temperature heat source, possibly fluctuating or even intermittent;

D/ being able to regulate very precisely and effectively the relationship between cold production and electricity production, preferably continuously (function D0).

No thermodynamic cycle as such can, by itself, achieve all of these functionalities.

Ammonia-water absorption systems have already well-identified advantages, such as allowing negative temperatures to be reached as well as the use of pressures higher than ambient, compared to H2O-LiBr absorption cycles. On the other hand, such systems do not comprise any fluid that could contribute to the destruction of the ozone layer or the increase in the greenhouse effect, as is the case with most organic fluids used in refrigeration.

On the other hand, hybrid systems have already been conceptualized for the co-production of electricity and cold.

Thus, a system for co-production of electricity and cold with an internal exchanger is known from the publication [1]. To achieve this, the operation of the system is based on a cycle that combines a Rankine cycle and a cold production cycle by absorption. The different components of the system are arranged in series in a closed fluidic circuit. The system described in this publication does not allow the conditions of electricity production and cold to be varied. The production of cold and the production of electricity are always simultaneous.

Also known from publication [2] and patent application EP3748274A1, a system for producing thermal energy and electrical energy comprising an absorption device comprising an absorber, a generator, a condenser, an evaporator and a fluidic circuit of absorption capable of receiving a working solution comprising a refrigerant and an absorbent, preferably the ammonia/water pair (NH3/H2O), the fluidic circuit connecting the generator to the condenser, the condenser to the evaporator, the evaporator to the absorbent and the absorbent to the generator, the system also comprising a reversible turbomachine type compressor in combination with a cooling fluid circulation management module in order to guarantee in a first mode of operation a production of electrical energy alternatively with a production of cold or heat, and in a second mode of operation to guarantee the production of electrical energy. The system described is compact, with a limited number of components and a low cost, which also allows possible integration in non-stationary applications. However, in this system according to publication [2] and document EP3748274A1, the aforementioned functions B/ and D/ are not necessarily possible due to:

• the importance of leaks leading to losses for very small flow rates in an expander-type volumetric machine, such as a scroll device;

• non-nominal behavior for a turbomachine type expander, for example an axial turbine, which implies a precise relationship between flow and inlet pressure in the expander.

Also known from patent ES2512990B1 is a system for co-production of electricity and cold that comprises, in addition to the traditional components of a system that implements an absorption cycle, an expander and an ejector arranged downstream of the expander, which has no impact positive in electricity production. The D/ function is not possible with a system according to document ES2512990B1. Furthermore, when reading this document, it is not clear how the working fluid flow rate is divided between cold production and electrical production and whether it is possible to vary the relationship.

On the other hand, variable section ejectors have recently been used in mechanical vapor compression cycles, with the aim of improving the performance of these cycles outside the nominal point: see for example the publication [3].

Therefore, there is a need to propose a cold and electricity co-production system that allows all the functions of the specifications mentioned above to be fulfilled, that is, functions A/ and D/ and preferably also function D0/.

The patent document EP 3748 137 A1 and the publication [4] also describe the cold and electrical energy production systems.

Presentation of the invention

To this end, the object of the invention is a cold and electrical energy production system that comprises:

• a desorber, called a generator,

• a capacitor,

• an evaporator,

• an absorbent,

• an absorption fluidic circuit in which a working fluid circulates that comprises a refrigerant and an absorbent, the fluidic circuit connecting the generator to the condenser, the condenser to the evaporator, the evaporator to the absorbent and the absorbent to the generator,

• a supersonic turbine arranged in the fluidic circuit between the generator and the absorber with bypass of the condenser and the evaporator, the turbine being configured to drive an electrical generator to produce electricity,

• at least one ejector arranged in the fluidic circuit between the generator and the turbine.

By “supersonic turbine” is meant here and within the scope of the invention, a turbine whose nominal operating speed is a high-speed supersonic flow.

The ejector may be a simple ejector or with a variable neck section.

By "ejector" is understood here and in the scope of the invention, a mechanical assembly that takes advantage of the depression created by the Venturi effect and that allows a secondary fluid to be compressed by mixing it with a pressurized primary fluid, the assembly not comprising moving parts that transmit energy. to the fluids.

By “ejector with variable neck section” here and in the scope of the invention is meant an ejector in which the dimensions of the ejector can be varied, which are mainly the diameters of the sonic neck section and/or of the mixer.

Advantageously, the working fluid comprises ammonia (NH3) as a cooling fluid and water (H2O) as an absorbent. Other refrigerant/absorbent pairs may be appropriate.

According to an advantageous embodiment, the fluidic circuit comprises an exchanger arranged in a fluidic bypass line, derived from the fluidic connection between the evaporator and the absorbent, the bypass line being connected to the injector of the secondary fluid of the ejector, so that the exchanger heats the secondary fluid before it enters the ejector.

Preferably, the turbine is configured to drive the working fluid circulation pump.

According to an advantageous embodiment, the system comprises a refrigerant fluid rectifier, arranged between the generator and the condenser.

According to this embodiment and an advantageous variant, the flows of the so-called rich and lean solutions of the working fluid are separated at the outlet of the generator or at the outlet of the rectifier.

According to another advantageous variant, the fluid, at the outlet of the working fluid circulation pump, is used as a cold source of the rectifier.

According to another advantageous embodiment, the system comprises a fluidic diversion line between the ejector and the absorber, in order to increase the pressure of the working fluid in the latter.

Advantageously, the system comprises, as a heat source, low temperature heat, advantageously between 70°C and 150°C.

The object of the invention is also a procedure for producing electrical energy and thermal energy implemented by means of a system such as the one described above that comprises:

• in a first mode of operation of cold production only, the circulation of the working fluid in the fluidic circuit successively through the generator, the condenser, the evaporator, then the absorber and then again in the generator;

• in a second mode of operation to produce electrical energy only, the circulation of the working fluid in the fluidic circuit successively through the generator, the supersonic turbine associated with an electrical generator, the absorber and then again in the generator;

• in a third mode of operation of co-production of cold and electrical energy, the circulation of a part of the working fluid in the fluidic circuit successively through the generator, the condenser, the evaporator, then the absorber, then again in the generator, and the other part of the working fluid passes successively through the generator, the supersonic turbine associated with an electrical generator, the absorber and then back into the generator;

• in a fourth mode of operation to co-produce cold and electrical energy with a regulated relationship between cold production and electrical production, the circulation of a part of the working fluid in the fluidic circuit successively through the generator, the condenser, the evaporator and after the absorber, then again in the generator, and the other part of the working fluid successively through the generator, the ejector, the supersonic turbine associated with an electrical generator, the absorber and then again in the generator.

The object of the invention is also the use of a cold and electrical energy production system as described above for electrical production with a power greater than 100 kWe.

Thus, the invention essentially consists, based on an electricity and cold production system as described in application EP3748274A1, choosing a supersonic turbine to reduce the leakage flow and guarantee the efficiency of electrical production, and adding water At the top is a simple or variable section ejector, which allows for a continuous increase in cold production while maintaining the efficiency of electrical production.

To carry out the different operating modes by performing the functions A/, B/, C/, D/ and D0/, the system comprises a working fluid management module that controls a set of adjustment valves, two expansion valves, of which the opening is adjustable and controls the speed of the pump depending on the fluctuation of the heat source or needs.

The ejector according to the invention makes it possible to increase the flow rate passing through the cold part of the working fluid circuit and, therefore, the cold power produced, while maintaining good electrical production performance (function D/).

The D0/ function is ensured by a change in the ejector section in order to optimize performance for each operating condition.

Numerous applications can be considered for a system according to the invention, among which can be mentioned:

• as stationary applications, the production of cold and electricity from low temperature heat sources (thermal expulsions from industrial processes, solar thermal, biomass, geothermal, gas turbines, networks);

• transportation applications with gasoline, diesel and gas turbine engines;

• transport applications in hybrid and electric vehicles with cold requirements.

Other advantages and characteristics will become clearer upon reading the detailed description, given for illustrative and non-limiting purposes, with reference to the following figures.

Brief description of the drawings

[Fig 1] Figure 1 represents a general scheme of a system according to the invention.

[Fig 2] Figure 2 resumes the scheme of the system according to Figure 1 that operates according to an operating mode that allows the production of cold only from a thermal source.

[Fig 3] Figure 3 resumes the scheme of the system according to Figure 1, operating according to an operating mode that allows the production of electrical energy only from a thermal source.

[Fig 4] Figure 4 resumes the scheme of the system according to Figure 1, operating according to an operating mode that allows the simultaneous co-production of electrical and cold energy from a thermal source.

[Fig 5] Figure 5 resumes the scheme of the system according to Figure 1 operating according to an operating mode that allows the simultaneous co-production of electrical and cold energy from a thermal source, with the possibility of adjusting the relationship between production of cold and electricity production.

[Fig 6] Figure 6 represents an advantageous arrangement scheme of an ejector upstream of a supersonic turbine in a system according to the invention.

Detailed description

It is specified that throughout the application, the terms “inlet”, “outlet”, “upstream”, “downstream” must be understood in relation to the direction of circulation of the fluid considered within a system according to the invention.

Likewise, throughout the application, the expression “component C1 fluidically connected to component C2” is synonymous with “C1 is in fluidic connection with C2”, and does not necessarily mean that there is no element between C1 and C2. The expressions “arranged on” or “on” are synonymous with “fluidly connected to.”

The term “arranged upon” means “in fluidic connection.”

All the fluidic connection lines of the fluidic absorption circuit are represented in the set of Figures 1 to 5 by means of continuous lines, without numerical reference for reasons of clarity. The direction of fluid circulation within a fluidic line is indicated by the direction of the arrow on this line.

The set of adjustment valves that operate on/off to carry out the different operations of the system according to the invention described with reference to Figures 1 to 5, is not designated with a numerical reference. However, when a considered valve is in the off state to perform one of the system operations, it is indicated by the cross-shaped symbol in the considered figure.

Direct exchange or direct coupling means that the exchange of thermal energy is carried out directly without an intermediate circuit or component. The direct exchange in the condenser or evaporator takes place directly between the refrigerant fluid and, for example, an air flow.

The system for producing electrical and cold energy according to the invention, as represented in Figure 1, comprises an absorption machine and a heat source, preferably a low temperature heat source, advantageously between 70°C and 150°C. °C, such as waste heat, which may be fluctuating, such as from a solar source, or waste heat related to the starting of a heat engine or intermittent industrial releases.

An absorption machine uses a binary mixture as a working solution, of which one of the components is more volatile than the other, and constitutes the refrigerant fluid. The refrigerant/absorbent fluid working solution is preferably the ammonia/water pair (NH3/H2O). The concentrations of the working fluid and the absorbent in the working solution are adapted to the pressure and temperature of the air treatment and are lower than the crystallization concentration of the solution.

The NH3/H2O pair can be used for air conditioning, but also refrigeration applications and crystallization is not possible in the pressure and temperature operating ranges. On the contrary, for this pair, the vapor pressure difference between the absorbent and the cooling fluid is low. Therefore, there are traces of water transported with the ammonia vapor at the outlet of the generator 1, sometimes requiring the presence of a rectifier 13.

The absorption machine comprises a set of four main exchangers, namely a generator 1, a condenser 2, an evaporator 3 and an absorber 4, and preferably at least one secondary exchanger. The four secondary exchangers illustrated, namely a subcooler 6, an economizer 8, a rectifier 13 or an exchanger 14, allow the machine's performance to be improved.

The absorption machine further comprises at least one dissolution pump 9 and an expansion valve 10 of a loop 11, and an expansion valve 12. The machine operates at three temperature levels: a low temperature level corresponding to the production of cold in the evaporator 3, an intermediate temperature level that corresponds to the condensation temperature of the refrigerant fluid, but also to the absorption of the refrigerant fluid by the absorber, and a high temperature level that corresponds to the engine temperature of the generator 1.

The absorption machine comprises a fluidic absorption circuit 100 configured to ensure the fluidic connection of the different components of the system, and in particular of the absorption machine. The fluidic absorption circuit 100 is a closed circuit intended to receive the working solution.

The absorption machine operates at high pressure between the pump 9 upstream of the generator 1 and the expansion valve 12, downstream of the condenser 2, and at low pressure between the expansion valve 2, downstream of the condenser 2 and the water pump 9. above generator 1.

The generator, also commonly called desorber 1, allows thermal exchange between the heat source and the working fluid. Such a generator 1 therefore comprises an inlet and a hot source outlet, not shown, that allow the input of heat necessary for the vaporization of the cooling fluid of the working solution. Generator 1 is fluidly connected to condenser 2 and absorber 4.

Preferably, an economizer 8 described below is arranged between the generator 1 and the absorber 4 to allow the entry of the so-called rich working solution into the generator 1 and the exit of the so-called lean working solution out of the generator 1.

The expansion valve 10 allows the pressure of the lean working solution to be relieved before it is transmitted to the absorbent 4.

Preferably, a rectifier 13 is arranged between the generator 1 and the condenser 2. The rectifier 13 eventually makes it possible to rectify the working solution, eliminating by condensation the traces of water entrained with the working fluid.

Condenser 2 allows the heat of the working fluid to be released to a source of intermediate temperature, condensing the refrigerant fluid vapor. Condenser 2 is fluidly connected to generator 1 and evaporator 3. The fluid connection between generator 1 and condenser 2 allows the entry of refrigerant fluid vapor into the latter. The expansion valve 12 brings the refrigerant fluid to its evaporation pressure and therefore allows the refrigerant fluid from the condenser 2 to exit in a liquid state. The condenser 2 also comprises a cooling source, such as an air circulation, to ensure its normal operation. The phase change of the refrigerant fluid from the vapor state to the liquid state is accompanied by a release of heat that is transmitted, for example, to the circulating air flow. The heated air is evacuated from the system.

The subcooler 6 is arranged between the condenser 2 and the evaporator 3, and between the evaporator 3 and the absorber 4, and allows the refrigerant fluid to be subcooled at the inlet of the evaporator 3 and to preheat the refrigerant fluid in a vapor state at the outlet of the evaporator. 3. The subcooler 6 therefore makes it possible to reduce the dimensions of the condenser 2 and the evaporator 3, and thus significantly improve the machine's performance. Preferably, as illustrated, the expansion valve 12 is arranged between the subcooler 6 and the evaporator 3.

Evaporator 3 allows heat to be taken from the cold source to vaporize the refrigerant fluid. The evaporator 3 is fluidically connected to the condenser 2 and the absorber 4. The phase change of the refrigerant fluid from the liquid state to the vapor state inside the evaporator 3 is accompanied by the transfer of heat from the hot source to the outlet of the evaporator 3 to the refrigerant fluid. This heat source transmits calories, and therefore sees its temperature drop. Evaporator 3 is the place of production of frigories.

The absorber 4 allows calories to be exchanged between the working fluid and a source at intermediate temperature, to condense the refrigerant fluid vapor from the evaporator 3. The absorber 4 is fluidly connected to the evaporator 3 and the generator 1 through loop 11.

The pump 9 of this loop 11 makes it possible to circulate the working solution in the circuit 100. More precisely, the pump 9 is intended to circulate the rich working solution from the absorbent 4 in the direction of the generator 1. The pump 9 consumes little electricity.

Even more precisely, the pump 9 is fluidly connected to the economizer 8 through which the rich working solution is heated before being transmitted to the generator 1. On the contrary, the economizer 8 transmits heat of the lean solution from the generator 1 to the rich solution from absorbent 4. Absorbent 4 is fluidically connected to generator 1 to allow the entry of the lean working solution from generator 1 into absorbent 4.

The expansion valve 10 is arranged between the generator 1 and the absorber 4. The phase change of the refrigerant fluid from the vapor state to the liquid state is accompanied by a release of heat that is transmitted to a cooling source such as a flow of air. The heated air is evacuated from the system.

According to the invention, a supersonic turbine 5 as an expander that drives a generator is arranged between the generator 1 and the absorber 4, bypassing the condenser 2 and the evaporator 3. This supersonic turbine 5 has a reduced leak rate and guarantees the efficiency of electricity production.

Also according to the invention, a simple or variable section ejector 50 is provided that allows the cold production to be continuously increased while maintaining the efficiency of the electrical production. The ejector 50 can be simple or with a variable section, as detailed below. A simple ejector 50 is optimized for a given relationship between cold production and electrical production (function D/), while a variable section ejector 50 allows very precise and effective regulation for all relationships between electrical production and electricity. cold production (function D0/).

The hydraulic connection allows the entry of the refrigerant fluid in a vapor state from the generator 1 directly to the turbine 5 or indirectly, in by-pass mode through the ejector 50.

A superheater 7 is arranged between the generator 1 and the turbine 5, preferably between the ejector 50 and the turbine to allow an additional heat exchange between a hot source not shown and the working fluid in order to obtain better quality steam at the turbine inlet 5.

The turbine 5 is fluidly connected to the absorber 4 to allow the exit of the refrigerant fluid in an expanded vapor state from the turbine 5 towards the absorber 4 according to a mode of electrical energy production.

The exchanger 14 is arranged in a fluidic line 15 in derivation from the fluidic connection between the evaporator 3 and the absorber 4. This fluidic line 15 is connected to the injector of the secondary (driven) fluid of the ejector 50. Thus, the exchanger 14 allows heating the secondary fluid before it enters the ejector 50.

The supersonic turbine 5 is advantageously connected to an electrical generator that allows the mechanical energy recovered by the turbine 5 to be transformed into electricity, producing an electrical power Wturb.

Typically, the supersonic turbine 5 is configured to allow an electrical production greater than 100 kWe, that is to say a medium power or even a high power of 1 MWe.

The system according to the invention further comprises a module for managing the circulation of the working solution within the circuit 100 and the various components of the system just described. The management module is configured to define system operating conditions based on power needs and source fluctuations, as detailed below. It may be the production of cold only, or the production of electrical energy, or the co-production of cold and electrical energy, depending on the temperatures of the sources and the price of electricity, etc.

This management module comprises the adjustment valves (on/off valves not shown), the two expansion valves 10, 12, whose opening is adjustable and a control unit that controls the speed of the pump 9, in order to allow a fine adjustment of the circulation flow rates of the working solution and the cooling fluid for the implementation of the system operating modes depending on the fluctuation of the heat source or needs.

The system and the management module according to the invention have the advantage of being compact, advantageously requiring only a few additional components such as valves, possibly temperature and pressure sensors, which reduces costs and the necessary volume, allowing The system according to the invention is used in mobile applications.

The different thermal and electrical powers of the different components of the system are represented in Figures 1 to 5 by the following symbols:

Qdes: generator 1 power;

Qcond: capacitor 2 power;

Qevap: evaporator power 3;

Qabs: absorbent power 4;

Wturb: work of supersonic turbine 5;

Qsub: power of subcooler 6;

QSH: superheater power 7;

QSHX: economizer power 8;

Wbomb: work of the pump of 9 of the working solution.

Qrect: rectifier power 13;

QHX: power of heat exchanger 14.

The operation of the system for a cold production is only shown in Figure 2. The module for managing the circulation of the working solution activates a circulation of the working solution following a classic absorption cycle. To do this, the module closes the adjustment valves in the fluid line on both sides of the ejector 50 and the turbine 5, as well as in the bypass line 15 upstream of the exchanger 14. In this way, the A/function is performed. .

The operation of the system according to Figure 2 to perform this function A/ is now described.

The working solution refrigerant fluid leaves generator 1 and passes through rectifier 13 before reaching condenser 2. The refrigerant fluid leaves condenser 2 to pass through subcooler 6, and expansion valve 12, before reach the evaporator 3. The refrigerant fluid leaves the evaporator 3 to pass through the subcooler 6 before reaching the absorber 4. The refrigerant fluid is absorbed by the absorber and the working solution called rich returns to the absorber 4 to circulate in loop 11.

In this loop 11, the rich working solution passes successively through pump 9 and economizer 8 before reaching generator 1. The lean working solution again leaves generator 1 to pass successively through economizer 8 and the expansion valve 10 before reaching the absorber 4. The production of cold is thus carried out at the level of the evaporator 3 during the evaporation of the refrigerant fluid which is accompanied by a cooling of the hot source. The cooled hot source can then be used, for example, for air conditioning.

The operation of the system for the production of electricity is only shown in Figure 3. The module for managing the circulation of the working solution activates a circulation of the working solution following a Rankine cycle, more specifically a Kalina cycle. To do this, the module closes the adjustment valves in the fluidic line on both sides of the ejector 50, in the fluidic line between the generator 1 and the rectifier 13 downstream of the bypass of the turbine line 5 as well as in the line between the evaporator 3 and the absorber 4 upstream of the bypass of the turbine line 5. In this way, function B/ is realized.

The operation of the system according to Figure 3 to carry out this function B/ is now described.

The cooling fluid of the working solution leaves the generator 1 and passes through the superheater 7 before reaching the turbine 5. The cooling fluid leaves the turbine 5 to empty into the absorber 4. The refrigerant fluid is absorbed by the absorber and the rich working solution leaves the absorber 4 again to pass through the loop 11 as described with reference to Figure 2 before returning to the level of the generator 1. The electricity is produced by the turbine 5 connected to a generator electric.

The operation of the system for simultaneous cold and electricity production is shown in Figure 4.

The working solution circulation management module activates a working solution circulation according to an absorption cycle and an electricity production cycle. To do this, the module closes only the adjustment valves in the fluidic line on both sides of the ejector 50. In this way, the C/ function is performed. Due to the use of a supersonic turbine 5, the flow rate is a function of upstream-downstream pressure jump and, therefore, the relationship between the cooling and electricity powers produced is fixed and cannot be modified.

The operation of the system is described below according to Figure 4 to perform this function C/.

At the outlet of generator 1, the cooling fluid of the working solution is directed partially towards the part of the circuit 100 that implements a cold production cycle and partially towards the other part that implements an electricity production cycle. Part of the cooling fluid leaving generator 1 is diverted to the supersonic turbine 5 while the other part circulates to condenser 2 passing upstream through rectifier 13. The cooling fluid again leaves condenser 2 to pass through the subcooler 6 and the expansion valve 12 before reaching the evaporator 3. The refrigerant fluid leaves the evaporator 3 to pass through the subcooler 6 before reaching the absorbent 4. The refrigerant fluid is absorbed by the absorbent and the working solution rich again leaves absorbent 4 to circulate in loop 11 and therefore pass successively through pump 9, economizer 8 before reaching generator 1. The lean working solution again leaves generator 1 to pass successively through the economizer 8 and the expansion valve 10 before reaching the absorber 4.

The part of the cooling fluid that passes through the supersonic turbine 5 passes upstream of the superheater 7. The cooling fluid then exits compressed again from the turbine 5 to empty into the absorber 4.

At the level of absorbent 4, the cooling fluid from turbine 5 and the cooling fluid from evaporator 3 are mixed before passing through loop 11. The cooling fluid is absorbed by the absorbent and the rich working solution comes out again. of the absorbent 4 to circulate in the loop 11 comprising the economizer 8, the pump 9 and the pressure regulator 10 as described above.

The production of cold is carried out at the level of evaporator 3 during the evaporation of the refrigerant fluid which is accompanied by a cooling of the hot source. The cooled hot source can then be used, for example, for air conditioning. Electricity is produced by the 5 supersonic turbine connected to an electric generator.

Figure 5 shows the operation of the system for simultaneous production of cold and electricity with the possibility of efficient adjustment of the relationship between these two productions.

The working solution circulation management module activates a working solution circulation according to an absorption cycle and an electricity production cycle with a relationship between the two. To do this, the module only closes the regulation valves in the fluidic line derived from that of the ejector 50 between the generator 1 and the turbine 5: thus, all the working fluid necessarily passes through the ejector 50 before flowing into the turbine. supersonic 5. In this way, the D/ function is realized, and preferably D0/ (ejector with variable neck section). The ejector 50 makes it possible to increase the flow rate that passes through the cold part of the circuit 100, and therefore the cold power produced, while maintaining good electrical production efficiency by the turbine 5. The D0/ function is guaranteed by the change of the ejector section with variable neck section in order to optimize performance in each operating condition.

The operation of the system according to Figure 5 to perform these functions D/ and D0/ is now described.

At the outlet of generator 1, the cooling fluid of the working solution is directed partially towards the part of the circuit 100 that implements a cold production cycle and partially towards the other part that implements an electricity production cycle. Part of the cooling fluid leaving generator 1 is diverted to the supersonic turbine 5 while the other part circulates to condenser 2 passing upstream through rectifier 13. The cooling fluid again leaves condenser 2 to pass through the subcooler 6 and the expansion valve 12 before reaching the evaporator 3. The refrigerant fluid leaves the evaporator 3 to pass through the subcooler 6.

A portion of the cooling fluid is then diverted into line 15 and passes through exchanger 14 to heat the fluid which is injected as secondary fluid into ejector 50.

The other part of the refrigerant fluid not diverted through line 15 reaches absorbent 4.

The refrigerant fluid is absorbed by the absorbent and the rich working solution leaves the absorbent 4 again to circulate in the loop 11 and therefore pass successively through the pump 9, the economizer 8 before reaching the generator 1. The Poor working solution leaves generator 1 again to pass successively through economizer 8 and expansion valve 10 before reaching absorber 4.

The part of the cooling fluid that passes through the supersonic turbine 5 necessarily passes upstream through the ejector 50, which increases the flow rate and then the superheater 7. The cooling fluid then comes out compressed again from the turbine 5 to empty into the absorbent 4.

At the level of absorbent 4, the cooling fluid from turbine 5 and the cooling fluid from evaporator 3 are mixed before passing through loop 11. The cooling fluid is absorbed by the absorbent and the rich working solution comes out again. of the absorbent 4 to circulate in the loop 11 comprising the economizer 8, the pump 9 and the pressure regulator 10 as described above.

The increased cold production with respect to Figure 4 takes place at the level of the evaporator 3 during the evaporation of the refrigerant fluid which is accompanied by the cooling of the hot source. The cooled hot source can then be used, for example, for air conditioning. Electricity is produced by the 5 supersonic turbine connected to an electric generator.

An example of a typical configuration for each system component is provided below:

• Generator 1 -Hot source temperature: 100°C

• Rectifier 13-rectification rate: 0.495

• Superheater 7-Temperature at the expander inlet (functions B/, C/, D/ and D0/): 120°C

• Condenser 2-Intermediate source temperature: 30°C

• Evaporator 3-superheat: : 5°C, Cold source temperature (function A/ and B/): 5°C, Cold source temperature (function D/ and D0/): 5°C

• Absorber 4-Intermediate source temperature: 30°C

• Pump 9-Flow 350 kg/h, Performance: 80%

• Compressor 5/Expander-Performance: 50%

The following tables 1 and 2 illustrate the performances that can be achieved with this example of a typical configuration of the operating modes that allows functions A/ to D0 to be carried out, with case 3 being the comparative one.

The performances were calculated using a digital model developed with the software marketed under the acronym EES (for “Engineering Equation Solver”) in which the energy and mass conservation equations are formulated for each component under the hypothesis of stationarity.

Therefore, these tables 1 and 2 summarize, from the different cases 1 to 4, the different powers, COP and performances for functions A/ to D/ with the typical configuration.

[Table 2]

In these tables 1 and 2:

CASE 1: Only cold production in the evaporator (function A/).

CASE 2: Simultaneous production of mechanical/electrical work by the turbine and cold production by the evaporator (function C/).

CASE 3: Regulation of the relationship between cold production and electricity production by performing a lamination before entering the turbine.

CASE 4: Regulation of the relationship between cold production and electrical production using the ejector according to the invention.

For the production of cold alone and combined with the production of electricity (functions A/, C/, D/ and D0/), the COP is defined by equation (1).

[Equation 1]

COP= WturQ

b.c.

+al

Wor

bomb (1)

in which Qcalor is the power, Q des delivered by the heat source at the level of generator 1, in the form of heat, Wturb the electrical power delivered by turbine 5, Wbomb the electrical power consumed by pump 9.

For the production of cold alone and combined with the production of electricity (functions A/, C/, D/ and D0/) the second principle of effectiveness is defined by equation (2):

[Equation 2]

Vu,cycle = Vn, cold x r s+Vil,powerx ( l —rs)(2)

with

[Equation 3]

[Equation 5]

COP = T{b.-g-e-n-+-W--b-o-m-b-)-x--r-s('5)'

[Equation 6]

m

VCarnot power(6)

[Equation 7]

[Equation 8]

W turbo

^ (Qgen+W bomb b ) x r$+QSH(8)

In cheeses, the relationship between the flow that passes through the cold part of the circuit and the flow produced by the generator,Tees the external temperature in the evaporator,Tcthe external temperature in the condenser,Tgla external temperature of the generator.

To highlight the contribution made by an ejector 50 according to the invention, the inventors carried out the simulation with a comparative configuration (case 3), similar to that typical of the invention but comprising a lamination valve instead of an ejector. In this comparative configuration, the ejector 50, line 15 and exchanger 14 are therefore eliminated and the laminating valve is arranged in the fluidic line between the generator 1 and the superheater 7, downstream of the line diversion towards condenser 2. Thus, in this comparative configuration (case 3), the relationship between electrical production and cold production is adjusted by the lamination valve.

Comparing the results of tables 1 and 2 between case 4 (ejector according to the invention) and case 3 (lamination valve), it is noted that the implementation of the ejector allows for almost the same cold power production and electrical production. much more important than with a lamination valve. This translates into a much higher electrical production efficiency and overall efficiency of the second cycle at the beginning of the cycle in the case of using the ejector compared to that of a lamination valve.

This higher production is due to the following increases:

• increase in the flow rate of working fluid through turbine 5 (16.77 kg/h with ejector versus 13.84 kg/h without ejector);

• increase in pressure upstream of turbine 5 (11.22 bar with ejector versus 9.335 bar without ejector);

• increased performance of turbine 5 (40% with ejector versus 18.4% without ejector);

• increased ammonia content (0.969 with ejector vs. 0.963 without ejector).

However, the use of an ejector implies a slight increase in the thermal power necessary for superheating by the exchanger 14.

The ejector 50 according to the invention is sized according to the nominal flow rate of the turbine 5 for electrical production (function D/). An example of the arrangement of an ejector 50 upstream of the superheater 7 and the supersonic turbine 5 is shown in Figure 6. For sizing it is necessary to correctly size the critical section of the sonic neck 51 of the primary fluidic injector, which defines the critical flow rate. treated by it, and its outlet section 53 that defines the outlet pressure of the injector and therefore influences the drive ratio.

An example of a calculation carried out with the EES software that corresponds to the configuration in Figure 6 is detailed in Table 3.

Table 3

In this configuration, the ejector 50 is sized to have a critical flow rate of 10 kg/h and a small drive ratio.

The use of a variable section ejector 50 allows the electrical production to be finely and efficiently regulated for different regimes (function D0/).

Other variants and improvements may be considered without departing from the scope of the invention.

Instead of a working solution composed of the ammonia/water pair, the use of ionic liquids can be considered in the system according to the invention.

In all operating modes in which the turbine 5 operates (functions B/, C/D/ and D0/), the turbine may not be connected to an electrical generator and produce only mechanical work.

It is possible to provide for the drive of the pump 9 by the turbine 5 in certain cases.

The working fluid flows can be separated at the outlet of rectifier 13, instead of at the outlet of generator 1 according to the configuration shown in Figure 1.

For the operation of the rectifier 13, the fluid leaving the pump 9 can be used as a cold source to rectify the ammonia.

A bypass fluidic line can be added to increase the pressure of the absorber 4 from the ejector 50.

The system may comprise at least one refrigeration storage module associated with the evaporator 3. Refrigeration storage thus allows energy storage when the source and the need are not concomitant. The stored frigories can be released in the form of cold or in the form of electricity depending on the needs. The cold storage module can be a thermal Phase Change Material storage system or directly a cold fluid storage. The frigories storage module is associated with the evaporator 3 to store frigories during operation for the production of cold. Advantageously, the refrigeration storage module is also associated with the absorber 4 to release refrigerants towards the absorber 4 when a cooling source is desired, that is, in particular in the different operating modes.

The system may comprise a frigories storage module associated with the absorber 4 to release the frigories.

The system may also comprise at least one calorie storage module associated with the absorber 4 or associated with the generator 1 to release calories.

The system may comprise at least one electricity storage module associated with the supersonic turbine 5 and more specifically with the electrical generator associated with the turbine 5. The electricity storage thus allows energy storage when the source and the need are not concomitant. The stored electricity can be released in the form of cold or in the form of electricity depending on the needs.

By way of example, electric batteries can be provided.

List of cited references

[1] : Gokmen Demirkaya, Ricardo Vasquez Padilla, Armando Fontalvo, Yee Yan Lim. "Thermal and Exergetic Analysis of the Goswami Cycle Integrated with Mid-Grade Heat Sources." August 2017 Entropy 19(8) :416. DOI: 10.3390/e19080416.

[2]: Voeltzel, N., Phan, H. T., Blondel, Q., González, B., and Tauveron, N., 2020, "Steady and Dynamical Analysis of a Combined Cooling and Power Cycle," Therm. Sci. Eng. Prog.,.19 (July), p. 100650.

[3]: Elbel, S., and Hrnjak, P., 2008, "Experimental Validation of a Prototype Ejector Designed to Reduce Throttling Losses Encountered in Transcritical R744 System Operation," Int. J. Refrig., 31 (3), pp. . 411-422.

[4] Ayou Dereje S. er al: "An overview of combined absorption power and cooling cycles", RENEWABLE AND SUSTAINABLE ENERGY REVIEWS, vol. 21, May 1, 2013 (2013-05-01), pages 728-748, XP055897934, US ISSN: 1364-0321, DOI: 10.1016/j.rser.2012.12.068

Claims (12)

1. System to produce cold and electrical energy, which includes: - a desorber, called a generator (1), - a capacitor (2), - an evaporator (3), - an absorbent (4), - an absorption fluidic circuit (100) in which a working fluid that comprises a refrigerant and an absorbent circulates, the fluidic circuit (100) connecting the generator (1) to the condenser (2), the condenser (2) to the evaporator (3), the evaporator (3) to the absorbent (4) and the absorbent (4) to the generator (1), - a supersonic turbine (5) arranged in the fluidic circuit (100) between the generator (1) and the absorber (4) with a bypass of the condenser (2) and the evaporator (3), the turbine being configured to drive an electric generator to produce electricity, - at least one ejector (50) arranged in the fluidic circuit between the generator and the turbine. 2. System according to claim 1, the ejector being a simple ejector or an ejector with variable cross-neck section. 3. System according to claim 1 or 2, the working fluid comprising ammonia (NH3) as a cooling fluid and water (H2O) as an absorbent. 4. System according to one of the preceding claims, the fluidic circuit (100) comprising an exchanger (14) arranged in a fluidic bypass line (15) in deviation from the fluidic connection between the evaporator (3) and the absorbent (4). , the bypass line (15) being connected to the secondary fluid injector of the ejector (50) so that the exchanger (14) heats the secondary fluid before its entry into the ejector (50). 5. System according to one of the previous claims, the turbine (5) being configured to drive the pump (9) for circulating the working fluid. 6. System according to one of the previous claims, comprising a rectifier (13) for the refrigerant fluid, arranged between the generator (1) and the condenser (2). 7. System according to claim 6, the flows of the so-called rich and lean solutions of the working fluid being separated at the outlet of the generator (1) or at the outlet of the rectifier (13). 8. System according to claim 6 or 7, the fluid at the outlet of the working fluid circulation pump (9) being used as a cold source of the rectifier (13). 9. System according to one of the preceding claims, comprising a fluidic bypass line between the ejector (50) and the absorber (4) in order to increase the pressure of the working fluid in the latter. 10. System according to one of the preceding claims, which comprises as a heat source heat at a low temperature, advantageously between 70°C and 150°C. 11. Procedure for producing electrical energy and thermal energy implemented by a system according to any one of the preceding claims, comprising: - in a first mode of operation of cold production only, the circulation of the working fluid in the fluidic circuit (100) successively through the generator (1), the condenser (2), the evaporator (3), then the absorber (4) and then again in the generator (1); - in a second mode of operation to produce electrical energy only, the circulation of the working fluid in the fluidic circuit (100) successively through the generator (1), the supersonic turbine (5) associated with an electrical generator, the absorber (4) and then again in the generator (1); - in a third mode of operation of co-production of cold and electrical energy, the circulation of a part of the working fluid in the fluidic circuit (100) successively through the generator (1), the condenser (2), the evaporator ( 3), after the absorber (4), then again in the generator (1), and the other part of the working fluid passes successively through the generator (1), the supersonic turbine (5) associated with an electrical generator , from the absorber (4) and then again into the generator (1); - in a fourth mode of operation to co-produce cold and electrical energy with a regulated relationship between cold production and electrical production, the circulation of a part of the working fluid in the fluidic circuit (100) successively through the generator (1), from the condenser (2), from the evaporator (3) and then from the absorber (4), then again into the generator (1), and the other part of the working fluid successively through the generator (1), from the ejector (50 ), from the supersonic turbine (5) associated with an electrical generator, from the absorber (4) and then again into the generator (1). 12. Use of a cold and electrical energy production system according to any one of claims 1 to 10 for electrical production of a power greater than 100 kWe.