FR2649620A1 - Installation and combined method of producing a solute and of cooling an enclosure from a main fluid composed of a solvent and a solute - Google Patents

Abstract

Recovery of energy in combined installations ensuring cooling and the production of a solute. The combined installation according to the invention comprises: @ an assembly 1 for cooling an enclosure L, including a closed cooling circuit 12 and a closed ice accumulation tank 11 connected to a main fluid; @ a cooling circuit 2 in thermal contact with the tank 11; @ a unit 3 for separating the components of the main fluid, comprising an exchanger 38 and a leaktight evacuated enclosure 42 ensuring separation of the components of the main fluid. Application to combined installations for production of soft water from sea water and for air conditioning of premises.

Description

INSTALLATION AND JOINT PROCESS FOR PRODUCING A SOLUTE AND
COOLING OF AN ENCLOSURE FROM A MAIN FLUID
COMPOUND OF SOLVENT AND SOLUTE
The present invention relates to the general technical field of methods and installations ensuring two complementary functions, associated within a unit with a view to improving the overall energy and economic balance.

 The invention relates, more particularly, to the technical field of heat exchange in air conditioning or cooling circuits, as well as to the technical field of the separation of the constituent elements of fluids composed of a solvent and a solute.

 The invention applies, more particularly but not exclusively, to the cooling and air conditioning of a room and to the production of fresh water by desalination of sea water.

The invention can also be applied to the cooling of any type of enclosure, whether, for example, a living room or a cold room for professional or private use.

 In the regions where Sévit a great heat and, for example, in the countries bordering the arid zones or even, more generally, in the hot regions of the globe, the demand for supply of fresh water turns out to be important and constantly growing in the weather. It therefore appears that the general climatic conditions of these regions of the globe are at the origin of the birth of a need for cold production to ensure the air conditioning of premises in general, on the one hand, and of a need on the other hand.

 Up to now, the two needs previously defined have always been considered separately, and the recommended solutions deal with the problems individually, often on an industrial scale and without taking into account the general living conditions prevailing in the countries concerned.

 Thus, it is already known to cool a room using a refrigeration unit ensuring the air conditioning of the room.

Different types of variable power installation are currently available and, in particular, devices using the concept of thermal storage. These devices, of particularly practical use in so far as the cooling load is irregular, make it possible to transfer the production of cooling to the desired period, and in particular in the case where electrical energy is less expensive during off-peak hours. The installations include a thermal storage unit, generally a refrigeration chamber, a compressor, a condenser, a refrigerant supply device, and a circulation pump. These devices produce, as a cold source in the refrigeration chamber , either iced water or ice, and have never been used up to now in an installation for the separation of a solvent and a solute, let alone in combination with a desalination unit seawater. In addition, the refrigerant supply device also has a hot source from which energy dissipates and which is unused,
In the field of seawater desalination, it is already known to have recourse to installations and processes involving a change of phase of the seawater. Among these processes, one can cite that of freezing which involves cooling and freezing seawater, then by direct melting of the frozen mass, collecting fresh water, and eliminating brine. It is also possible to use distillation or crystallization techniques by evaporation to obtaining fresh water from sea water. These techniques which are known and used on an industrial scale are, inter alia, simple distillation, or with multiple effects, distillation by successive detents hereinafter called "flash process""and steam compression distillation. These three variants of the same technique consist in vaporizing sea water in a sealed enclosure, generally under vacuum, and in condensing the vapor on a beam located in this same enclosure. Condensation leads to the formation of a distillate, in this case the fresh water which is collected. Similarly, it can be practiced crystallization by evaporation of water vapor under vacuum, after increasing the temperatures, l fresh water being recovered by condensation. The salt is removed after filtration.

 The above-described desalination processes and installations are designed to operate individually and permanently and therefore include their own internal energy sources. In addition, the facilities are sized to meet industrial production requirements, unrelated to the freshwater requirements that arise on an individual scale.

 At the present time, there are no processes or installations making it possible, simultaneously and for a low cost, to cool a room and produce fresh water from the same basic fluid.

 The object of the invention is to propose a method and an installation ensuring, in a combined and complementary manner, the air conditioning of a room and the production of fresh water from the same main fluid, in this case water. by sea, using simple and proven technical means while minimizing operating energy losses.

 Another object of the invention is to provide a method and an installation operating with various main types of fluids, the size of which is relatively small, and accommodating discontinuous operation of the air conditioning unit.

 Another object of the invention is to adapt and combine, as economically as possible, the technical elements relating to the accumulation of ice with those relating to the production of fresh water by freezing and distillation or crystallization.

The object of the invention is achieved by a mixed installation for producing a solute and cooling an enclosure from a main fluid composed of a solvent and a solute, such as seawater , comprising:
- an enclosure cooling assembly including
a closed cooling circuit in which
circulates a water-type heat transfer fluid
glycolée for example set in motion by a
means of circulation,
and a closed ice storage tank,
heat exchange relationship with the circuit
cooling, linked, on the one hand, to the source of the
main fluid and, on the other hand, to a tank of
recovery of the solute from its fusion
and to a rejection pipe,
- a refrigeration circuit in thermal relation with
the tank closed and able to supply, by
through a heat transfer fluid, a means
~ 4) increase in its energy potential and a
means of relaxation, the energy required for
solid formation in the closed tank at
from the main fluid,
- a unit for separating the compounds from the fluid
main including
a main fluid circulation circuit
connected, on the one hand, to the fluid source
main and, on the other hand, to the circuit of
refrigeration via an exchanger
to recover thermal energy from the source
of the refrigeration circuit,
a sealed vacuum chamber interposed in
the main fluid circulation circuit
in which the separation of
composed of the main fluid.

The object of the invention is also achieved by a mixed process for producing a solute and cooling an enclosure from a main fluid composed of a solvent and a solute which consists in
- build up a solid solute reserve from
main fluid using a circuit
refrigeration,
cool the enclosure by melting the enclosure with a
cooling assembly using the reserve of
solid as a cold source,
- recover the solute from the fusion of the solute,
- maintain, at least discontinuously, the
constitution of the solid reserve by
through the refrigeration circuit,
- separate in a sealed enclosure under circulating vacuum
in a separate circuit, the solvent for the solute,
recovering in the circuit the energy transferred by the
hot source of the refrigeration circuit,
- recover the solute produced.

 Various other characteristics will emerge from the description given below with reference to the appended drawings which show, by way of nonlimiting examples, embodiments of the subject of the invention.

 Fig. t shows a block diagram of a first variant of an installation in accordance with the invention.

 Fig. 2 shows another diagram corresponding to a second variant of an installation according to the invention.

 The first embodiment illustrated in FIG. I comprises a cooling assembly 1 of a room or an enclosure L, a refrigeration circuit 2 of the cooling assembly 1, and a separation unit 2.

 The refrigeration circuit 2 comprises the conventional basic elements of a mechanical refrigeration system, namely a means of raising the energy potential of the refrigerant, such as a compressor 4, a condenser 5, an expansion valve 6 or a pressure reducer , an electrical supply cabinet 9 and an evaporation unit 7 in thermal relation with the cooling assembly 1. These various elements are connected to each other by means of a refrigeration circuit 8 dahs lequeL circulates a fluid coolant whose expansion ensures the production of cold and which can be, for example, ammonia, a halocarbon refrigerant or even any equivalent fluid commonly used in refrigeration circuits.

 The compression means 4 will be chosen from among all of the means for raising the energy potential of a fluid and may be, in particular, of the piston type for small refrigeration circuits or alternatively screw, in the case of big size. It is also possible to use an absorption machine or an auxiliary steam supply. The condenser 5 will be chosen from condensers with water, air or other cooling.

 The refrigeration circuit 2 is responsible for supplying, through its cold source and in particular through its evaporation unit 7, the cooling energy required by the refrigeration unit 1 in room L.

The thermal relationship between the Evaporation Unit 7 and
The refrigeration assembly 1 is preferably carried out by passing a coil of multiple-tube coil, for example, through a closed tank 11 included in the cooling assembly 1.

The latter is of the ice accumulation type and comprises a closed cooling circuit 12 in which circulates, in the direction indicated by the arrows in the figures and by
The intermediary of a circulation means 13 which can be a pump, a heat transfer fluid 14 of the brine type for example. The circuit 12 connects the room to be cooled L with the closed tank 11 which comprises a sealed outer casing 15 which can be of very thick steel and hot-dip galvanized and insulated with expanded polystyrene for example. A second sealed envelope 16 is provided inside the external envelope 15, in order to be in permanent heat exchange relation with the heat transfer fluid 14 contained in the external envelope 15.

The second sealed envelope 16, called the internal envelope, constitutes the actual ice accumulation unit and includes, for this purpose, the coil battery of the
refrigeration 2, which battery is responsible for forming and producing, from a main fluid 17 contained in the internal envelope 16, ice crystals.

 The main fluid 17 is a flu-ide composed of a solvent and a solute and, in a preferred application of the invention, it is sea water, the fresh water contained in the latter constituting the solute. Seawater is taken from the source in the ocean by a pump 18 and brought by a series of pipes 21 and control valves 22 into the internal envelope 16. There is also an outlet pipe 23, at bottom of the internal casing 16, coupled to an extraction pump 24. The pipe # outlet 23 leads to a discharge branch 23a provided with a control valve 25 and to a branch 26 for recovering the solute connected to a solute recovery tank 27.

 A stirring system 28 of the main fluid 17 composed, for example, of an air pump and an ejection manifold 31 provided with stirring nozzles 32, is incorporated in the refrigeration assembly 1, in view to improve and homogenize the formation of ice crystals.

The outer casing 15 can also include a drainage circuit connected to the lower part of the outer casing 15 for the rejection of the heat-carrying fluid 14 and to the upper part of the outer casing 15 for the rejection of the gaseous phases, by
Through a control valve. This drainage circuit can, of course, also be coupled with the casing
internal 16.

 It is also possible to provide, on the pipe 23, to incorporate a device for measuring the electrical conductivity of the circulating fluid, with a view to correlating the salinity of said fluid and thus controlling the separation by the control valve 25. The cooling of the room L from the cooling circuit 12 is ensured using elements well known to those skilled in the art, such as ventilation ducts 33 and fans 34 and are therefore not described more in detail.

 The installation according to the invention also comprises a separation unit ′ 3 for the compounds of the main fluid 17 which is preferably sea water. In the example shown in FIG. 1, the separation unit is a distillation unit which comprises a circuit for circulation of the main fluid 17 including, in particular, a supply pipe 37 for main fluid 17 connected directly or not to the supply pipe 21 of the installation. This circuit is also connected to the refrigeration circuit 2 via an exchanger 38, in which the thermal energy from the hot source of the refrigeration circuit 2 is transferred to the distillation unit. The basic principle used in the distillation unit is that of single or multiple effects distillation or that of distillation by successive detents, called flash distillation.

 The energy transferred is recovered by the main fluid 17 in movement in a pipe 41 of the circulation circuit which opens into a sealed enclosure 42. A return pipe 41a ensures the return of the main fluid 17 to the exchanger 38. The enclosure tight 42 is permanently maintained under vacuum by means of a vacuum station 44 including, for example, a hydro-ejector, a heat exchanger-condenser 43 and a vacuum tube 45. The heat-exchanger 43, in which takes place the condensation of the steam coming from the sealed enclosure 42 and also the recovery of the solute, is connected by a line 46 for recovering the solute and by a pump 47 to the recovery tank 27. The circulation circuit also comprises a line for inlet 49 in seawater connected to the condensing exchanger 43 to the sealed enclosure 42. It is possible to provide an outlet pipe 50 connected to the supply pipe 49 to ensure, if necessary oin est, the rejection of sea water.

The sealed enclosure 42 is finally provided with an evacuation pipe 52 for its contents after distillation, in this case the solvent, the pipe being able to be connected to the pipe 41a for recycling.

 It is also possible to plan to open the recovery pipe 46 in which the solute circulates, that is to say fresh water in the most frequent case, in the internal envelope 16, by connection to a branch 51 , in order to ensure the cleaning of the ice, and thus to reduce bleeding. In the example shown in fig. 1, the enclosure 42 acts as a buffer tank responsible for ensuring the thermal damping of the variations in temperatures of the main fluid 17, the supply temperature of which in the enclosure 42 is determined from the refrigeration circuit 2 which operates from discontinuously. The sealed enclosure 42 also provides a hydraulic buffer function for the vacuum circuit of the distillation unit and allows, by stirring, an almost continuous purging of the gaseous phases of the recycling circuit.

 If seawater is used as the main fluid in the distillation unit and in the ice storage tank 16, corrosion will be avoided by the choice of noble metals, of the stainless steel, bronze d aluminum, cupro-nickel in non-inspectable parts of the installation.

 It will also be possible to use plating techniques on all or part of or the sealed enclosure 42. Chemical treatments able in particular to avoid scaling of the installation may also be carried out.

 The mixed process and installation described operate in the following manner.

 During the hours when electrical energy is the least expensive, the refrigeration circuit 2 ensures, in a discontinuous manner, the constitution of a reserve of ice in the reservoir 16 from sea water which has previously been introduced by the pipe 21 and the valve 22. The production of ice is carried out in a conventional manner by expansion of the heat transfer fluid and refrigeration exchange with sea water at the level of the coil coil. The ice reserve being constituted, the operation of the refrigeration circuit can be stopped in connection with a device for sensing the thickness of ice for example.

 In the event of a cooling demand from the room or from the enclosure L, the cooling load is supplied by the melting of the ice which gives up the coolant 14 to its coolant.

 The melting of the ice leads to the recovery of the fresh water obtained by fusion. The recovery of the solute, in this case fresh water, is done by elimination of the brine first by means of your pipe 23, then the salinity decreasing as the discharge, by recovery of the water fresh in the tank 27 after the pipeline 26 has been put into service.

 The coolant of the refrigeration circuit 2 gives up its calories, coming from its compression in the compressor 4, to the sea water circulating in the pipe 41, which sea water will relax in the sealed enclosure under vacuum 42 and produce The energy required for vaporization and then for the condensation of the vapor in the exchanger-condenser 43 which contains cooler sea water coming from the pipe 49. The distilled fresh water is therefore collected and the brine returns by pipes 41a and 52 to the exchanger 38. The fresh water collected is either recovered in the tank 27 for personal use, or returned directly to the enclosure 16 for cleaning purposes in particular, to facilitate, if necessary , heat exchanges, when the ice melts.

 The distillation unit thus provides, by using a theoretically lost source of recovery heat and use of the temperature variation between the sea water taken at the source and the sea water coming from the exchanger 38, an additional quantity of fresh water obtained with a particularly favorable energy and economic balance.

 The installation thus described therefore makes it possible, from a main fluid whose quantity is unlimited and whose temperature is relatively low, to ensure, with a relatively low energy consumption, the coverage of a need for cooling and a need for fresh water, while taking advantage of periods when electrical energy is the cheapest.

The discontinuity in operation of the cooling unit 1 and of the refrigeration circuit 2 also makes it possible to overcome any power cuts, by accumulating ice preventively.

 Fig. 2 shows a second variant embodiment according to the invention which does not differ from the variant shown in FIG. 1 only by replacing the distillation unit with an evaporation crystallization unit capable of ensuring greater production. Indeed, this kind of installation is more appropriate when larger quantities of fresh water are required, since due to the prolonged residence time of the sea water in the sealed enclosure 42 allowed by this technique, the 'waterproof enclosure 42 can be large. Most of the elements already present in the distillation unit are found in the crystallization unit. To improve and homogenize evaporation, we plan to install a mixing device 60 of seawater in the sealed enclosure. 42. Furthermore, the almost complete evaporation of the liquid phase of the sea water through the pipe 45 then the exchanger-condenser 43 leads to obtaining, at the bottom of the sealed enclosure 42, an almost solid salt. For this purpose, it may be advantageous to have, at the outlet of the sealed enclosure 42, a filtering means 61, comprising for example a wringer to recover a perfectly solid salt by the discharge element 62. The remaining liquid phase , generally in small quantities, can be recycled through line 63 in the sealed enclosure 42. Due to its small volume, the quantity recycled does not have a significant impact on the salinity of the sea water contained in the sealed enclosure 42. On the other hand, it can be useful for initiating the crystallization process.

 Various modifications can be made to the two variant embodiments described and, in particular, in place of seawater, it is possible to use other fluids composed of a solvent and a solute, the amount of which n 'is not limited and has a temperature close to 200C and, for example, isobutane, butane or benzene, or even brackish water taken from an additional source, such as a river. It is also conceivable to use only a single envelope for the production of the ice accumulation unit in the case of connection to a pre-existing air conditioning installation, and to provide a buffer tank separate from L ' waterproof enclosure.

 The invention is not limited to the examples described and shown, since various modifications can be made thereto without departing from its scope.

Claims (12)

 1 - Mixed installation for producing a solute and for cooling an enclosure (L) from a main fluid (17) composed of a solvent and a solute, in particular of the seawater type, comprising:  a cooling assembly (1) of the enclosure  (L) including:  - a closed cooling circuit (12)  In which circulates a fluid  coolant, of the brine type by  example, set in motion by a means of  circulation (13),  - and a closed storage tank (11)  ice, in heat exchange relationship  with the cooling circuit (12),  connected, on the one hand, to the source of the fluid  main (17) and, on the other hand, to a tank  recovery (27) of the solute from  of its merger and to a pipeline of  rejection (23a),  a refrigeration circuit (2) in relation  thermal with the tank closed (11) and capable of  provide, through a fluid  coolant, a means (4) for raising its  energy potential and a means of relaxation  (6), the energy required to build up  solid in the closed tank (11) from the  main fluid (17),  a separation unit (3) for the compounds of  main fluid (17) comprising  - a circulation circuit (37, 41, 41a,  45, 63) of the main fluid (17) connected,  on the one hand, at the source of fluid  main and, on the other hand, to the circuit of  refrigeration (2) via a  exchanger (38) to recover energy  circuit heat source thermal  refrigeration (2),  - a sealed enclosure (42) under vacuum  interposed in the circulation circuit  (37, 41, 41a, 45, 63) of the main fluid  (17), in which The  separation of compounds from the fluid  main.  2 - Installation according to claim 1, characterized in that the sealed enclosure (42) acts as a buffer tank capable of absorbing thermal variations from the refrigeration circuit (2) and is connected directly to the exchanger (38) by a pipe (41).  3 - Installation according to claim 2, characterized in that the separation unit (3) is a distillation unit comprising a recycling branch (41a) of the main fluid (17) or solvent to the exchanger (38).  4 - Installation according to claim 3, characterized in that the distillation unit (3) is of the single or multiple effects type and comprises at least one flash distillation station.  5 - Installation according to claim 2, characterized in that the separation unit (3) is a vacuum crystallization unit.  6 - Installation according to at least one of the preceding claims, characterized in that the installation comprises a return circuit (51) of the solute to the closed enclosure (11).  7 - Installation according to claim 1, characterized in that the closed reservoir (11) with ice accumulation consists of a double reservoir including an outer heat envelope (15) filled with heat transfer fluid inside which is located a internal envelope (16) for ice accumulation.  8 - Mixed process for the production of a solute and the cooling of an enclosure from a main fluid composed of a solvent and a solute which consists in:  constitute a. solid solute reserve from  of the main fluid using a  refrigeration (2),  cool the solute by melting the enclosure (L)  by a cooling assembly (1) using  the reserve of solid as a cold source,  . recover the solute from the fusion of  solute,  . maintain, at least discontinuously, the  constitution of the solid reserve by  The intermediary of the refrigeration circuit (2),  . separate in a sealed enclosure (42) under vacuum  circulating in a separate circuit, the solvent  solute, recovering energy from the circuit  yielded by the hot spring of the circuit of  refrigeration (2),  . recover the solute produced.  9 - Process according to claim 8, characterized in that it consists in using sea water as the main fluid and thus producing fresh water as a solute.  10 - Process according to claim 8 or 9, characterized in that it consists in separating the solvent from the solute in the sealed enclosure (42), using the temperature difference between the source of main fluid and the main fluid having recovered the energy transferred from the hot source of the refrigeration circuit, to separate the main fluid in the sealed enclosure (42) under vacuum.  11 - Process according to claim 10, characterized in that it consists in separating the solvent from the solute by distillation in the sealed enclosure (42).  12 - Process according to claim 10, characterized in that it consists in separating the solvent from the solute by crystallization in the sealed enclosure (42).