A heating and cooling system using solar energy, comprising: ▪ a solar water heater comprising: ∘ a solar collector; and ∘ a storage mean thermally coupled with the solar collector to transfer solar energy collected by the solar collector to a liquid present in the storage mean; ▪ an absorption chiller comprising: ∘ an evaporator containing a refrigerant and capable of being thermally coupled with a first hot source to cool the latter; ∘ an absorber, in communication with the evaporator to receive refrigerant therefrom and to cool the received refrigerant by absorbing it in a solution containing an absorbent, to form a refrigerant-enriched absorbent solution; ∘ a desorber, capable of being thermally coupled with a second hot source (16, 20), the desorber being in communication with the absorber to receive refrigerant-enriched absorbent solution therefrom, and to separate said solution by desorbing refrigerant by means of the second hot source, and in communication with the absorber to supply it with a solution of refrigerant-depleted absorbent; and ∘ a condenser capable of being thermally coupled with a cold source, the condenser being in communication with the desorber to receive desorbed refrigerant therefrom and to condensate the received refrigerant by means of the cold source, and in communication with the evaporator to supply it with condensed refrigerant; the desorber comprising an exchanger in communication with the absorber to receive refrigerant-enriched absorbent solution therefrom, the exchanger being housed in the storage mean, said storage mean forming the second hot source; characterized in that the storage mean is a storage tank and in that the disrober comprises a liquid/vapor separator in communication: ▪ with the exchanger to receive therefrom the refrigerant-enriched absorbent solution heated in the exchanger, and to decant said enriched solution between, on the one hand, a refrigerant-depleted absorbent solution and, on the other hand, refrigerant; ▪ with the absorber to supply it with the refrigerant-depleted absorbent solution; and ▪ with the condenser to supply it with refrigerant. ▪ a solar water heater comprising: ∘ a solar collector; and ∘ a storage mean thermally coupled with the solar collector to transfer solar energy collected by the solar collector to a liquid present in the storage mean; ∘ a solar collector; and ∘ a storage mean thermally coupled with the solar collector to transfer solar energy collected by the solar collector to a liquid present in the storage mean; ▪ an absorption chiller comprising: ∘ an evaporator containing a refrigerant and capable of being thermally coupled with a first hot source to cool the latter; ∘ an absorber, in communication with the evaporator to receive refrigerant therefrom and to cool the received refrigerant by absorbing it in a solution containing an absorbent, to form a refrigerant-enriched absorbent solution; ∘ a desorber, capable of being thermally coupled with a second hot source (16, 20), the desorber being in communication with the absorber to receive refrigerant-enriched absorbent solution therefrom, and to separate said solution by desorbing refrigerant by means of the second hot source, and in communication with the absorber to supply it with a solution of refrigerant-depleted absorbent; and ∘ a condenser capable of being thermally coupled with a cold source, the condenser being in communication with the desorber to receive desorbed refrigerant therefrom and to condensate the received refrigerant by means of the cold source, and in communication with the evaporator to supply it with condensed refrigerant; ∘ an evaporator containing a refrigerant and capable of being thermally coupled with a first hot source to cool the latter; ∘ an absorber, in communication with the evaporator to receive refrigerant therefrom and to cool the received refrigerant by absorbing it in a solution containing an absorbent, to form a refrigerant-enriched absorbent solution; ∘ a desorber, capable of being thermally coupled with a second hot source (16, 20), the desorber being in communication with the absorber to receive refrigerant-enriched absorbent solution therefrom, and to separate said solution by desorbing refrigerant by means of the second hot source, and in communication with the absorber to supply it with a solution of refrigerant-depleted absorbent; and ∘ a condenser capable of being thermally coupled with a cold source, the condenser being in communication with the desorber to receive desorbed refrigerant therefrom and to condensate the received refrigerant by means of the cold source, and in communication with the evaporator to supply it with condensed refrigerant; ▪ with the exchanger to receive therefrom the refrigerant-enriched absorbent solution heated in the exchanger, and to decant said enriched solution between, on the one hand, a refrigerant-depleted absorbent solution and, on the other hand, refrigerant; ▪ with the absorber to supply it with the refrigerant-depleted absorbent solution; and ▪ with the condenser to supply it with refrigerant.