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.

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 M 1 , H 1 , H 2 , M 2 , B, using a heat source whereof the temperature is at a value Th of about or higher than 70° C. during the phases H 1  and H 2 , at an intermediate value Tm during the phases M 1  and M 2 , 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 H 1 , H 2 ), 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 M 1 , M 2 ), 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 H 1  and H 2 , while one dipole produces refrigeration; 
 one or two dipole(s) is (are) regenerated indirectly during each phase M 1  and M 2 , 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 H 1  and H 2  during which the heat is available at the highest temperature Th, during phase M 2  during which the heat is available at an intermediate temperature Tm, the device being in regeneration during phase M 1  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 M 1 , 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 H 1 , 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 H 2 , 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 M 2 , 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 M 2 , 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 M 1  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 M 1 , 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 H 1 , 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 H 2 , 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 M 2 , 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 M 2 , 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 H 1 , H 2 , M 2  and B; the device is in regeneration during phase M 1 ; 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 M 1 , 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 H 1 , 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 H 2 , 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 M 2 , 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 M 2 , 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.