This device comprises a closed circuit comprising exchangers 3 which are arranged in the greenhouse 1 and in which a hot heat-exchanging liquid circulates, and a heat pump 10 for reheating said heat-exchanging liquid in contact with the condenser 11 of the pump. It is characterised in that it comprises moreover a condensation battery 30, through which the internal air in the greenhouse passes, means 17 for making cold heat-exchanging liquid circulate through the condensation battery and means for cooling the cold heat-exchanging liquid in contact with the evaporator 13 of the heat pump. Application to making devices for air-conditioning greenhouses. <IMAGE>
