Method for refrigerating an isothermal box to a target temperature and associated facility

A facility for refrigerating a thermally insulated housing (C) substantially to a target temperature Te, comprising:

• a thermally insulated housing (C);
• an evaporator (E) arranged in said housing (C) and containing a fluid in liquid phase in equilibrium with the gaseous phase thereof;
• at least one thermochemical reactor Ri containing a reactive mixture Si capable of chemically reacting with said gaseous-phase fluid in order to form a reaction product, said chemical synthesis reaction of said reaction product being exothermic and reversible, said thermochemical reactor Ri being capable of being placed in fluid communication with said evaporator (E) via a duct Li equipped with valve-forming means (Vi);
• means of evacuating the heat (VT1;
• VT2, Rd1;
• Rd2);
• means of measuring the temperature in said thermally insulated housing (C);
• means of heating said thermochemical reactor(s) Ri which are capable of inducing the reverse endothermic reaction of decomposition of said reaction product, resulting in the regeneration of said reactive mixture and said gaseous-phase fluid;
• furthermore, at least n thermochemical reactors Ri+1, n being a whole number equal to or greater than 1, each reactor Ri+1 containing a reactive mixture Si+1, optionally identical to said reactive mixture Si and also capable of chemically reacting with said gaseous-phase fluid in order to form a reaction product, said chemical synthesis reaction of said reaction product being exothermic and reversible, each of said n thermochemical reactors being capable of being placed in fluid communication with said evaporator (E) via a specific duct Li+1;
• a valve Vi+1 mounted on each of said ducts Li+1 and which in open position allows the fluid connection between said reactor and said evaporator (E), and in closed position, isolates said reactor Ri from said evaporator (E) and from said other n thermochemical reactors
• means of heating each of said thermochemical reactors Ri+1 which are capable of inducing the reverse endothermic reaction of decomposition of said reaction product, resulting in the regeneration of said reactive mixture and said gaseous-phase fluid;
• and
• heat evacuation means suitable for evacuating the heat generated by said synthesis reaction from each of said thermochemical reactors Ri and Ri+1 in which such reaction takes place;
• means of comparing the difference between the temperature measured in said housing (C) and said target temperature Te with a third predetermined differential (ΔT3);
• and/or
• means of determining the temperature Tev in said evaporator (E) and/or the pressure Pev in said evaporator (E) or in each of said reactors Ri and Ri+1;
• means of determining the temperature Ti in said reactor Ri and in each thermochemical reactor Ri+1 of said n+1 reactors;
• means of determining the differential DTev between the temperature of said housing (C) and the temperature of said evaporator (E);
• and/or
• means of determining the differential DTRi between said determined temperature Ti and the equilibrium temperature TeSi of said reactive mixture Si contained in said thermochemical reactor Ri considered at said pressure Pevi determined in said evaporator (E);
• and/or
• means of comparing DTRi and/or DTev respectively with a first and a second predetermined differential (ΔT1;
• ΔT2), and
• means of controlling the open/closed position of each of said valves Vi and Vi+1, said means of control being coupled to said means of comparison and configured to place in fluid communication said evaporator (E) with at least one thermochemical reactor Ri+1 chosen from among the thermochemical reactors that are not in fluid communication with said evaporator (E) and for which the pressure is lower than the pressure Pevi determined in said evaporator (E) and/or the temperature is lower than a given value when said comparison means have determined that DTRi and/or DTev is/are lower respectively than said first and said second differential (ΔT1;
• ΔT2);
• possibly an assembly of at least one external thermochemical reactor different from said assembly of n reactors and different from said reactor Ri and capable of being placed in fluid communication with said evaporator (E) by at least one duct equipped with valve-forming means;
• and the means of control are coupled to the means of comparison in order to place said evaporator (E) in fluid connection with at least one portion of said n reactors, when the differential between the temperature in said housing and said target temperature Te is equal to said third differential ΔT3 or to place the evaporator (E) in fluid connection with said assembly of the at least external thermochemical reactor when the differential between the temperature in said housing and the target temperature is equal to said third differential ΔT3.