Producing Cold by a Thermochemical Method for Air-Conditioning a Building

Abstract

The present invention relates to a device and a method for air conditioning a building using an intermittent heat source whereof the maximum temperature is 70° C. and a heat sink at a temperature of 15° C. The device comprises 3 or 4 thermochemical dipoles each comprising an evaporator-condenser unit and a reactor connected by means for circulating G between them and means for interrupting the flow of G. The reactors are the seat of reversible processes between G and a liquid or a solid, and the evaporators-condensers are the seat of a liquid-gas phase change of G; the reactors are equipped with means for exchanging heat between them and means for controlling the heat exchange; the thermochemical processes in the dipoles may be identical or different; the device comprises a heat source at a variable temperature Tc, the maximum temperature being 70° C., and a heat sink at a temperature To of 15° C.

Description

The present invention relates to a device for producing of refrigeration by a thermochemical method, for air conditioning a building.

BACKGROUND OF THE INVENTION

The system consisting of a thermochemical dipole using two reversible thermochemical processes is a means known per se for producing of refrigeration. The thermochemical dipole comprises a reactor BT, a reactor HT and means for exchanging a gas between BT and HT. The two reactors are the seat of reversible thermochemical processes selected such that, at a given pressure in the dipole, the equilibrium temperature in BT is lower than the equilibrium temperature in HT. The reversible process in the reactor HT employs a sorbent S and a gas G and may be a reversible adsorption of G by S or a reversible chemical reaction of S and G, according to the equation

“Sorbent S”+“G”⇄“sorbent S+G”.

The reversible process in the reactor BT employs the same gas G. It may be a liquid/gas phase change of the gas G or a reversible adsorption of G by a sorbent S¹ or a reversible chemical reaction of S¹ and G, the sorbent S¹ being different from S. The production of refrigeration step of the device corresponds to the synthesis step in HT

“Sorbent S”+“G”→“sorbent S+G”.

The regeneration step corresponds to the decomposition step in HT

“Sorbent S+G”→“sorbent S”+“G”.

The production of refrigeration at a temperature Tf in a dipole (BT,HT) using a heat source at the temperature Tc and a heat sink at the temperature To, implies that the thermochemical process in BT and the thermochemical process in HT are such that:

• • during the step of production of refrigeration by the dipole, the exothermic consumption of gas in HT takes place at a temperature close to and higher than To, which creates in the dipole a pressure such that the equilibrium temperature in the reactor BT is close to and lower than Tf;
  • during the dipole regeneration step, the endothermic liberation of gas in HT is obtained by adding heat at the temperature Tc, which creates a pressure in the dipole such that the temperature at which the exothermic consumption of gas takes place in BT is close to and higher than To.

The thermochemical process in a reactor BT is generally a liquid/gas phase change of G. BT is then an evaporator/condenser unit EC.

The use of thermochemical devices for air conditioning buildings is attractive, insofar as the devices concerned are quiet and do not generate vibrations. In general, these devices use the subsoil as a heat sink, which is virtually permanently at a temperature of 15° C. in temperate regions. Furthermore, since the air conditioning is mainly necessary during very hot periods, it may be possible to use the solar energy which is particularly abundant during these periods. However, the heat collected by inexpensive flat collectors is at a temperature which generally does not exceed 70° C. Much higher temperatures can only be obtained with high technology and particularly expensive solar collectors, such as vacuum collectors, or parabolic or cylindro-parabolic concentration collectors. Furthermore, the solar energy undergoes variations in intensity, on the one hand during the year, and on the other during a day.

Thermochemical processes are known for producing of refrigeration from a heat source at a temperature Tc of about 70°, and a heat sink at a temperature To of about 15° C. For example, use can be made in the reactor BT of the dipole, of an L/G phase change of ammonia (NH₃), methylamine (NH₂CH₃) or H₂O. For the reactors, mention can be made of a reversible chemical sorption of NH₃ by CaCl₂, by BaCl₂, by PbBr₂, by PbCl₂, by LiCl, by SnCl₂, by ZnSO₄ or by NH₄Br, or NH₂CH₃ by CaCl₂; or an adsorption of water by zeolite or a silica gel; or the adsorption of methanol (MeOH) or ammonia in active carbon; or the absorption of NH₃ in a liquid solution of ammonia (NH₃, H₂O) or of H₂O by a salt solution of LiBr.

SUMMARY OF THE INVENTION

It is the object of the present invention to provide a device for air conditioning a building, said device consisting of a plurality of thermochemical dipoles operating between a heat source at a temperature Tc associated with solar energy and a heat sink at a temperature To of about 15° C., particularly using known thermochemical processes employing a working gas such as ammonia, methylamine or water.

The present invention relates to a device and a thermochemical method for air conditioning a building using an intermittent heat source whereof the maximum temperature is about 70° C. and a heat sink at a temperature of about 15° C.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows, on a Clapeyron diagram, the variation in the temperature and pressure conditions in the device during each of the active phases. The curves 2 correspond to the thermochemical equilibrium in each of the reactors, and the curves 1 correspond to the thermochemical equilibrium in each of the evaporators-condensers. The letters a, b and c indicate the dipole concerned by the variation.

FIG. 2 shows, on a Clapeyron diagram, the variation in the temperature and pressure conditions in the device during each of the phases. The curves 2 correspond to the thermochemical equilibrium in each of the reactors, and the curves 1 correspond to the thermochemical equilibrium in each of the evaporators-condensers. The letters a, b and c indicate the dipole concerned by the variation.

FIG. 3 shows, on a Clapeyron diagram, the variation in the temperature and pressure conditions in the device during each of the active phases. The curves 1 correspond to the thermochemical equilibrium in each of the evaporators-condensers, the curves 2 correspond to the thermochemical equilibrium in each of the reactors Ra and Rc, and the curves C correspond to the thermochemical equilibrium in the reactors Rb and Rd. The letters a, b, c and d indicate the dipole concerned by the variation.

FIG. 4 shows the particular Clapeyron diagram for the phases M1 and M2. During this step, refrigeration may be produced at a temperature close to 0° C. using a heat source lower than 50° C.

FIG. 5 shows the particular Clapeyron diagram for phases H1, H2 and M2. During this step, refrigeration may be produced at a temperature close to 0° C. using a heat source lower than 70° C.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The inventive device comprises three or four thermochemical dipoles each comprising an evaporator-condenser unit EC and a reactor R connected by means for circulating a gas G between them and means for interrupting the gas flow. It is characterized in that:

• • the reactors are the seat of reversible processes between the gas G and a liquid or a solid, and the evaporators-condensers are the seat of a liquid-gas phase change of G;
  • the reactors R are equipped with means for exchanging heat between them and means for controlling the heat exchange;
  • the thermochemical processes in the various dipoles may be identical or different;
  • the device comprises a heat source at a variable temperature Tc, whereof the maximum temperature Th is about 70° C., and a heat sink at a temperature To of about 15° C.

In such a device, in which the unit EC of each dipole is the seat of a liquid/gas phase change of the working gas G, the temperature in R is naturally higher than the temperature in EC, for a given dipole.

The thermochemical processes in the various dipoles preferably have similar equilibrium curves to limit the external heat losses of the reactors. Two equilibrium curves of two thermochemical processes are considered to be similar when, at a given equilibrium pressure, the respective equilibrium temperatures differ by not more than 15° C. It is particularly advantageous to select the same thermochemical process in all the dipoles.

The dipoles of the inventive device are denoted below by Da (consisting of the evaporator-condenser ECa and the reactor Ra), Db (consisting of ECb and Rb), Dc (consisting of ECc and Rc), and optionally Dd (consisting of ECd and Rd).

During a daily 24-hour cycle comprising the successive phases M1, H1, H2, M2, B, the solar collectors supply heat available at a temperature Tc that varies according to the phases of the cycle. During phases H1 and H2 of total insolation, the heat supplied is close to the value Th of about 70° C. During phase M1 which precedes or phase M2 which follows the full insolation, the heat produced is an intermediate temperature Tm of between Th and To but nevertheless usable as a heat source. During the night or in the absence of sunlight (phase B), the heat is at a temperature Tb close to the ambient temperature To, and therefore too low to be usable as a heat source.

The method of the present invention is intended for producing of refrigeration by 24-hour cycles which each comprise the successive phases M1, H1, H2, M2, B, using a heat source whereof the temperature is at a value Th of about or higher than 70° C. during the phases H1 and H2, at an intermediate value Tm during the phases M1 and M2, and at a value Tb close to the ambient temperature during phase B. It is characterized in that it consists in operating the inventive device, in order to create internal heat sources at a temperature above the temperature of the external source, during the periods when said temperature is too low, particularly during phases M1 and M2.

More particularly, the producing of refrigeration method of the invention consists in operating the inventive device under the following conditions:

• a) each dipole is regenerated by sending to reactor R of said dipole a quantity of heat supplied by the solar collector, the addition being made:
  • either directly to the reactor R of the dipole to be regenerated when the heat is supplied by the heat source at a high temperature (phases H1, H2), the reactors R of two dipoles being capable of simultaneously receiving the heat at high temperature Th;
  • or indirectly when the heat is supplied at an intermediate temperature Tm (phases M1, M2), the heat then being supplied to the evaporator-condenser EC of a regenerated dipole to generate therein the exothermic synthesis phase in the corresponding reactor R, said synthesis liberating a quantity of heat at a temperature above Tm and close to Th, which is transferred to the reactor R of a dipole to be regenerated;
• b) the heat is introduced into the device in such a way that:
  • two dipoles are regenerated simultaneously (directly or indirectly) during phases H1 and H2, while one dipole produces refrigeration;
  • one or two dipole(s) is (are) regenerated indirectly during each phase M1 and M2, one of the other dipoles optionally producing of refrigeration;
  • optionally, one dipole produces refrigeration during phase B.

A given dipole is totally or partially regenerated at the end of a complete cycle, according to the quantity of heat available during the regeneration step and the quantity of refrigeration required during the production of refrigeration step of a complete cycle.

In a first embodiment, the inventive method is implemented in a device consisting of three dipoles Da, Db and Dc in which the thermochemical processes are identical, in order to produce refrigeration during phases H1 and H2 during which the heat is available at the highest temperature Th, during phase M2 during which the heat is available at an intermediate temperature Tm, the device being in regeneration during phase M1 and inactive in phase B.

FIG. 1 shows, on a Clapeyron diagram, the variation in the temperature and pressure conditions in the device during each of the active phases. The curves 2 correspond to the thermochemical equilibrium in each of the reactors, and the curves 1 correspond to the thermochemical equilibrium in each of the evaporators-condensers. The letters a, b and c indicate the dipole concerned by the variation.

At the end of phase B, the evaporator-condenser is isolated from the reactor in each of the dipoles, and the various dipoles are in the following state:

Da to be regenerated

Db to be regenerated

Dc partially regenerated.

At the start of phase M1, the gas connection between ECa and Ra is opened, on the one hand, and between ECc and Rc on the other, and heat is added at the temperature Tm to ECc of the dipole Dc (point D1). This heat addition causes the evaporation of the gas G which is transferred to the reactor Rc in which the exothermic synthesis phase then takes place (point S2). The heat liberated by said synthesis is transferred to Ra where it causes the liberation of the gas G (point D2). The gas liberated in Ra is transferred to ECa where it condenses while liberating heat (point S1). At the end of phase M1, the dipoles are in the following state:

Da partially regenerated

Db to be regenerated

Dc to be regenerated.

At the start of phase H1, the gas connection between ECb and Rb is opened. During phase H1, the dipoles Db and Dc are regenerated by direct addition of heat at the temperature Th in Rb and Rc (points D2). The gas liberated in Rb and Rc is transferred respectively to ECb and ECc where it condenses (points S1). Simultaneously, refrigeration is produced by the dipole Da in ECa by removing heat from the medium to be cooled (point D1). At the end of phase H1, the dipoles are in the following state:

Da to be regenerated

Db partially regenerated

Dc totally regenerated.

During phase H2, heat is added at the temperature Th to the reactors Ra and Rb (points D2) to continue regenerating Db and to start regenerating Da. Simultaneously, refrigeration is produced spontaneously in ECb (point D1). At the end of phase H2, the dipoles are in the following state:

Da partially regenerated

Db totally regenerated

Dc to be regenerated.

During phase M2, heat is added at the temperature Tm to ECa (point D1) to cause the exothermic synthesis in Ra whereof the heat is transferred to Rc to regenerate the dipole Dc. Simultaneously, refrigeration is produced spontaneously in ECb. At the end of phase M2, the dipoles are in the following state:

Da to be regenerated

Db to be regenerated

Dc partially regenerated.

At the end of phase M2, the gas connections between the evaporators-condensers and the reactor of the same dipole are closed and the installation is left as such during phase B, up to the start of phase M1 of the next cycle.

In a second embodiment, the method is implemented in a device which comprises three identical dipoles Da, Db and Dc, in order to produce refrigeration during all the phases of a 24-hour cycle.

FIG. 2 shows, on a Clapeyron diagram, the variation in the temperature and pressure conditions in the device during each of the phases. The curves 2 correspond to the thermochemical equilibrium in each of the reactors, and the curves 1 correspond to the thermochemical equilibrium in each of the evaporators-condensers. The letters a, b and c indicate the dipole concerned by the variation.

At the end of phase B, the evaporator-condenser is isolated from the reactor in each of the dipoles, and the various dipoles are in the following state:

Da partially discharged

Db to be regenerated

Dc partially discharged.

At the start of phase M1, heat is added at the temperature Tm to ECc (point D1/c) to cause the exothermic synthesis in Rc (point S2/c) whereof the heat is transferred to Rb (point D2/b) to regenerate the dipole Db. Simultaneously, refrigeration is produced spontaneously at ECa (point D1/a). At the end of phase M1, the dipoles are in the following state:

Da partially discharged

Db partially regenerated

Dc to be regenerated.

During phase H1, the dipoles Db and Dc are regenerated by direct addition of heat at the temperature Th in Rb and Rc (points D2/b and D2/c). Simultaneously, refrigeration continues to be produced at ECa (point D1/a). At the end of phase H1, the dipoles are in the following state:

Da to be regenerated

Db totally regenerated

Dc partially regenerated.

During phase H2, heat is added at the temperature Th to the chambers Ra and Rc (points D2/a and D2/c) to continue regenerating Dc and to start the regeneration of Da. Simultaneously, refrigeration is produced spontaneously at ECb (point D1/b). At the end of phase H2, the dipoles are in the following state:

Da partially regenerated

Db partially discharged

Dc totally regenerated.

Durant phase M2, heat is added at the temperature Tm to ECc (point D1/c) to cause the exothermic synthesis in Rc (point S2/c) whereof the heat is transferred to Ra to initiate the regeneration of the dipole Da. Simultaneously, refrigeration is produced spontaneously at ECb (point E2/b). At the end of phase M2, the dipoles are in the following state:

Da totally regenerated

Db to be regenerated

Dc partially discharged.

At the end of phase M2, the gas connections between ECb and Rb are closed on the one hand, and between ECc and Rc on the other. During phase B, the gas connection is maintained in the dipole Da and refrigeration is produced at ECa (point D1/a). At the end of phase M2, the dipoles are in the following state:

Da partially discharged

Db to be regenerated

Dc partially discharged.

During phase B, the device continues to produce refrigeration by the dipole Da.

In a third embodiment, the method is implemented in a device which comprises four dipoles Da, Db, Dc and Dd, in order to produce refrigeration during phases H1, H2, M2 and B, the device being in regeneration during phase M1. The dipoles Da and Db are thermally coupled. The dipoles Dc and Dd are thermally coupled.

FIG. 3 shows, on a Clapeyron diagram, the variation in the temperature and pressure conditions in the device during each of the active phases. The curves 1 correspond to the thermochemical equilibrium in each of the evaporators-condensers, the curves 2 correspond to the thermochemical equilibrium in each of the reactors Ra and Rc, and the curves C correspond to the thermochemical equilibrium in the reactors Rb and Rd. The letters a, b, c and d indicate the dipole concerned by the variation.

The reactors Ra and Rc of the dipoles Da and Dc are the seat of the same thermochemical process, and the reactors Rb and Rd of dipoles Db and Dd are the seat of the same process, different from the one taking place in the dipoles Da and Dc. Furthermore, all the chemical processes employ the same working gas G, so that all the evaporators-condensers are the seat of a liquid-gas phase change of the same gas G. Thus, at a given pressure prevailing identically in the four dipoles, the equilibrium temperatures in the various chambers are as follows:

t(ECa)=t(ECb)=t(ECc)=t(ECd)<t(Ra)=t(Rc)<t(Rb)=t(Rd)

At the end of phase B, the gas connection between EC and R of each dipole is closed and the various dipoles are in the following state:

Da regenerated

Db to be regenerated

Dc regenerated

Dd to be regenerated.

During phase M1, the gas connection between ECa and Ra is opened on the one hand, and between ECb and Rb on the other, heat is added at the temperature Tm to ECa (point E1/a) of the dipole Da to cause the exothermic synthesis in Ra (point S2/a) whereof the heat is transferred to Rb (point D3/b) to regenerate the dipole Db. At the end of phase M1, the dipoles are in the following state:

Da to be regenerated

Db regenerated

Dc regenerated

Dd to be regenerated.

At the start of phase H1, the gas connection between ECa and Ra is opened on the one hand, and between Ecd and Rd on the other. During phase H1, heat is added at the temperature Tm to ECc of the dipole Dc (point D1/c) to cause the exothermic synthesis in Rc (point S2/c) whereof the heat is transferred to Rd (point D3/D) to regenerate the dipole Dd. Simultaneously, refrigeration is produced spontaneously at ECb (point E1/b), causing the exothermic synthesis in Rb (point S3/b) whereof the heat is transferred to Ra (point D2/a) to regenerate the dipole Da. At the end of phase H1, the dipoles are in the following state:

Da regenerated

Db to be regenerated

Dc to be regenerated

Dd regenerated.

During phase H2, heat is added at the temperature Tm to ECa (point E1/a) of the dipole Da to cause the exothermic synthesis in Ra (point S2/a) whereof the heat is transferred to Rb (point D3/b) to regenerate the dipole Db. Simultaneously, refrigeration is produced spontaneously at ECd (point E1/d), causing the exothermic synthesis in Rd (point S3/d) whereof the heat is transferred to Rc (point D2/c) to regenerate the dipole Dc. At the end of phase H2, the dipoles are in the following state:

Da to be regenerated

Db regenerated

Dc regenerated

Dd to be regenerated.

During phase M2, heat is added at the temperature Tm to ECc (point E1/c) of the dipole Dc to cause the exothermic synthesis in Rc (point S2/c) whereof the heat is transferred to Rd (point D3/d) to regenerate the dipole Dd. Simultaneously, refrigeration is produced spontaneously at ECb (point E1/b), causing the exothermic synthesis in Rb (point S3/b) whereof the heat is transferred to Ra (point D2/a) to regenerate the dipole Da. At the end of phase M2, the dipoles are in the following state:

Da regenerated

Db to be regenerated

Dc to be regenerated

Dd regenerated.

At the end of phase M2, the gas connections between ECa and Ra are closed on the one hand, and between ECb and Rb on the other. During phase B, refrigeration is produced spontaneously at Rd (point E1/d), causing the exothermic synthesis in Rd (point S3/d) whereof the heat is transferred to Rc (point D2/c) to regenerate the dipole Dc. At end of phase B, the dipoles are in the following state:

Da regenerated

Db to be regenerated

Dc regenerated

Dd to be regenerated.

The present invention is illustrated by the following examples.

Example 1

This example illustrates an implementation of the 2^nd embodiment of the inventive method.

The evaporator-condenser of each of the three dipoles is the seat of a liquid/gas phase change of NH₃. The reactor of each of the dipoles is the seat of a reversible chemical reaction between NH₃ and BaCl₂.

FIG. 4 shows the particular Clapeyron diagram for the phases M1 and M2. During this step, refrigeration may be produced at a temperature close to 0° C. using a heat source lower than 50° C.

Example 2

This example illustrates an implementation of the 3^rd embodiment of the inventive method.

The evaporator-condenser of each of the four dipoles is the seat of a liquid/gas phase change of NH₃.

The reactor of each of the dipoles Da and Dc is the seat of a reversible chemical reaction between NH₃ and BaCl₂. The reactor of the dipole Db and Dd is the seat of a reversible chemical reaction between NH₃ and ZnSO₄.

FIG. 5 shows the particular Clapeyron diagram for phases H1, H2 and M2. During this step, refrigeration may be produced at a temperature close to 0° C. using a heat source lower than 70° C.

Claims

1. A device for air conditioning a building using an intermittent heat source whereof the maximum temperature Th is about 70° C. and a heat sink at a temperature of about 15° C., which comprises three or four thermochemical dipoles Da, Db, Dc and optionally Dd, each comprising an evaporator-condenser unit EC and a reactor R (denoted respectively by ECa and Ra for Da, ECb and Rb for Db, ECc and Rc for Dc, and ECd and Rd for Db) connected by means for circulating a gas G between them and means for interrupting the gas flow, wherein:

the reactors are the seat of reversible processes between the gas G and a liquid or a solid, and the evaporators-condensers are the seat of a liquid-gas phase change of G;

the reactors R are equipped with means for exchanging heat between them and means for controlling the heat exchange;

the thermochemical processes in the various dipoles may be identical or different;

the device comprises a heat source at a variable temperature Tc, whereof the maximum temperature Th is about 70° C., and a heat sink at a temperature To of about 15° C.; and

the thermochemical processes in the various dipoles have equilibrium curves such that, at a given equilibrium pressure, the respective equilibrium temperatures differ by not more than 15° C.

2. The device as claimed in claim 1, wherein the thermochemical process is the same in all the dipoles.

3. A method for producing refrigeration by 24-hour cycles which each comprises the successive phases M1, H1, H2, M2, B, using a heat source whereof the temperature is at a value Th of about or higher than 70° C. during the phases H1 and H2, at an intermediate value Tm during the phases M1 and M2, and at a value Tb close to the ambient temperature during phase B, wherein it consists in operating a device as claimed in claim 1, so as to create internal heat sources at a temperature above the temperature of the external source, during the periods when said temperature is too low.

4. The method as claimed in claim 3, wherein:

a) each dipole is regenerated by sending to reactor R of said dipole a quantity of heat supplied by the solar collector, the addition being made: either directly to the reactor R of the dipole to be regenerated when the heat is supplied by the heat source at a high temperature (phases H1, H2), the reactors R of two dipoles being capable of simultaneously receiving the heat at high temperature Th; or indirectly when the heat is supplied at an intermediate temperature Tm (phases M1, M2), the heat then being supplied to the evaporator-condenser EC of a regenerated dipole to generate therein the exothermic synthesis phase in the corresponding reactor R, said synthesis liberating a quantity of heat at a temperature above Tm and close to Th, which is transferred to the reactor R of a dipole to be regenerated; and

b) the heat is introduced into the device in such a way that: two dipoles are regenerated simultaneously (directly or indirectly) during phases H1 and H2, while one dipole produces refrigeration; one or two dipole(s) is (are) regenerated indirectly during each phase M1 and M2, one of the other dipoles optionally producing of refrigeration; optionally, one dipole produces refrigeration during phase B.

5. The method as claimed in claim 4, wherein it is implemented in a device consisting of three dipoles Da, Db and Dc in which the thermochemical processes are identical, in order to produce refrigeration during phases H1 and H2 during which the heat is available at the highest temperature Th, during phase M2 during which the heat is available at an intermediate temperature Tm, the device being in regeneration during phase M1 and inactive in phase B.

6. The method as claimed in claim 5, wherein, from a state corresponding to the end of phase B, in which the evaporator-condenser is isolated from the reactor in each of the dipoles, Da is to be regenerated, Db is to be regenerated and Dc is partially regenerated;

at the start of phase M1, the gas connection between ECa and Ra is opened, on the one hand, and between ECc and Rc on the other, and heat is added at the temperature Tm to ECc, thereby causing the evaporation of the gas G which is transferred to Rc in which the exothermic synthesis phase then takes place, the heat liberated by said synthesis being transferred to Ra where it causes the liberation of the gas G which is transferred to ECa where it condenses while liberating heat;

at the start of phase H1, the gas connection between ECb and Rb is opened and Db and Dc are regenerated by direct addition of heat at the temperature Th in Rb and Rc, the gas liberated in Rb and Rc being transferred respectively to ECb and ECc where it condenses; simultaneously, refrigeration is produced by Da in ECa by removing heat from the medium to be cooled;

during phase H2, heat is added at the temperature Th to Ra and Rb to continue regenerating Db and to start regenerating Da; simultaneously, refrigeration is produced spontaneously in ECb;

during phase M2, heat is added at the temperature Tm to ECa to cause the exothermic synthesis in Ra whereof the heat is transferred to Rc to regenerate the dipole Dc; and

at the end of phase M2, the gas connections between EC and R of the same dipole are closed and the installation is left as such during phase B, up to the start of phase M1 of the next cycle.

7. The method as claimed in claim 4, wherein it is implemented in a device which comprises three dipoles Da, Db and Dc which are the seat of identical thermochemical processes, in order to produce refrigeration during all the phases of a 24-hour cycle.

8. The method as claimed in claim 7, wherein, from a state corresponding to the end of phase B, in which the evaporator-condenser is isolated from the reactor in each of the dipoles, Da is in the partially discharged state, Db is to be regenerated, and Dc is partially discharged;

at the start of phase M1, heat is added at the temperature Tm to ECc to cause the exothermic synthesis in Rc whereof the heat is transferred to Rb to regenerate the dipole Db, and simultaneously, refrigeration is produced spontaneously at ECa;

during phase H1, the dipoles Db and Dc are regenerated by direct addition of heat at the temperature Th in Rb and Rc and simultaneously, refrigeration continues to be produced at ECa;

during phase H2, heat is added at the temperature Th to Ra and Rc to continue regenerating Dc and to start the regeneration of Da and, simultaneously, refrigeration is produced spontaneously at ECb;

during phase M2, heat is added at the temperature Tm to ECc to cause the exothermic synthesis in Rc whereof the heat is transferred to Ra to initiate the regeneration of Da and, simultaneously, refrigeration is produced spontaneously at ECb; and

at the end of phase M2, the gas connections between ECb and Rb are closed on the one hand, and between ECc and Rc on the other, and during phase B, the gas connection is maintained in Da and refrigeration is produced at ECa.

9. The method as claimed in claim 4, wherein it is implemented in a device which comprises four dipoles Da, Db, Dc and Dd, in order to produce refrigeration during phases H1, H2, M2 and B; the device is in regeneration during phase M1; Da and Db are thermally coupled and Dc and Dd are thermally coupled; the reactors Ra and Rc are the seat of the same thermochemical process, and the reactors Rb and Rd are the seat of the same process, different from the one taking place in the reactors Ra and Rc; all the chemical processes employ the same working gas G, so that all the evaporators-condensers are the seat of a liquid-gas phase change of the same gas G.

10. The method as claimed in claim 9, wherein, from a state corresponding to the end of phase B, in which the gas connection between the two chambers of each dipole is closed, Da is regenerated, Db is to be regenerated, Dc is regenerated and Dd is to be regenerated:

during phase M1, the gas connection between ECa and Ra is opened on the one hand, and between ECb and Rb on the other, heat is added at the temperature Tm to ECa to cause the exothermic synthesis in Ra whereof the heat is transferred to Rb to regenerate the dipole Db;

at the start of phase H1, the gas connection between ECa and Ra is opened on the one hand, and between Ecd and Rd on the other; heat is added at the temperature Tm to ECc to cause the exothermic synthesis in Rc whereof the heat is transferred to Rd to regenerate the dipole Dd and, simultaneously, refrigeration is produced spontaneously at ECb causing the exothermic synthesis in Rb whereof the heat is transferred to Ra to regenerate Da;

during phase H2, heat is added at the temperature Tm to ECa to cause the exothermic synthesis in Ra whereof the heat is transferred to Rb to regenerate Db and, simultaneously, refrigeration is produced spontaneously at ECd causing the exothermic synthesis in Rd whereof the heat is transferred to Rc to regenerate Dc;

during phase M2, heat is added at the temperature Tm to ECc of Dc to cause the exothermic synthesis in Rc whereof the heat is transferred to Rd to regenerate Dd and, simultaneously, refrigeration is produced spontaneously at ECb, causing the exothermic synthesis in Rb whereof the heat is transferred to Ra to regenerate Da; and

at the end of phase M2, the gas connections between ECa and Ra are closed on the one hand, and between ECb and Rb on the other, and, during the subsequent phase B, refrigeration is produced spontaneously at Rd, causing the exothermic synthesis in Rd whereof the heat is transferred to Rc to regenerate Dc.