The invention concerns a device for the simultaneous production of heat and cold designed for being coupled with a pump (30) for cooling a refrigerating fluid supplying the air conditioning system of a building (40) and comprising a separator (32) for separating by evaporation and condensation the two constituents, one of which is volatile, from a first refrigerating fluid and a mixer (34) for forming back by evaporation and absorption this first refrigerating fluid. This device comprises a boiler-separator (44) including a combustion chamber (48) designed for being connected with the cooling pump (30) for heating the first refrigerating fluid in order to separate its constituents and a desorbing unit (50), or concentrator, for separating by the effect of the heat released by the combustion chamber (48) the two constituents, one of which is volatile, from a second refrigerating fluid and a mixer (54) for forming back, by absorption of a volatile constituent derived from a heating condenser (52) of the separator (32) of the cooling pump (30), this second refrigerating fluid. The invention also concerns the assembly formed by an existing cooling pump coupled with a device for the simultaneous production of heat and cold.