Device for storage of heat/cold by means of transfer from a fluid, known as a charge fluid, for subsequent reuse by means of transfer to a fluid, known as a discharge fluid, said device comprising: - an external rigid container forming the walls (106 1 ; 106 2 ; 106 3 ; 106 4 ; 106 5 , 106 6 ) of said device ; - a rigid storage module arranged inside said external container and comprising an internal rigid container forming the walls of said storage module , and a storage assembly arranged inside said internal container designed for storage of the calories/frigories; - a cold external interface (104 1 ) arranged on a wall (106 1 ; 106 2 ; 106 3 ; 106 4 ; 106 5 , 106 6 ) of the external container and in communication with a cold internal interface (110 1 ) arranged on the storage module , said cold interfaces (104 1 , 110 1 ) ensuring the passage of the so-called cold fluids between the cold external interface (104 1 ) and the storage module ; - a hot external interface (104 2 ) arranged on a wall (106 1 ; 106 2 ; 106 3 ; 106 4 ; 106 5 , 106 6 ) of the external container and in communication with a hot internal interface (110 2 ) arranged on the storage module , said hot interfaces (104 2 , 110 2 ) ensuring the passage of the so-called hot fluids having a temperature greater than the temperature of the cold fluids, between the hot external interface (104 2 ) and the storage module ; said hot and cold external interfaces (104 1 , 104 2 ) being arranged on a single wall (106 1 ) or on two adjacent walls of said external container ; and wherein - a flexible insulating layer and/or a rigid insulating layer is or are arranged between the storage assembly and the internal rigid container . - an external rigid container forming the walls (106 1 ; 106 2 ; 106 3 ; 106 4 ; 106 5 , 106 6 ) of said device ; - a rigid storage module arranged inside said external container and comprising an internal rigid container forming the walls of said storage module , and a storage assembly arranged inside said internal container designed for storage of the calories/frigories; - a cold external interface (104 1 ) arranged on a wall (106 1 ; 106 2 ; 106 3 ; 106 4 ; 106 5 , 106 6 ) of the external container and in communication with a cold internal interface (110 1 ) arranged on the storage module , said cold interfaces (104 1 , 110 1 ) ensuring the passage of the so-called cold fluids between the cold external interface (104 1 ) and the storage module ; - a hot external interface (104 2 ) arranged on a wall (106 1 ; 106 2 ; 106 3 ; 106 4 ; 106 5 , 106 6 ) of the external container and in communication with a hot internal interface (110 2 ) arranged on the storage module , said hot interfaces (104 2 , 110 2 ) ensuring the passage of the so-called hot fluids having a temperature greater than the temperature of the cold fluids, between the hot external interface (104 2 ) and the storage module ; said hot and cold external interfaces (104 1 , 104 2 ) being arranged on a single wall (106 1 ) or on two adjacent walls of said external container ; and wherein - a flexible insulating layer and/or a rigid insulating layer is or are arranged between the storage assembly and the internal rigid container . <EOS>