The invention concerns a device and a method for air-conditioning a building from an intermittent heat source, the maximum temperature of which is 70 deg.C and a heat sink at a temperature of 15 deg.C. The device comprises three or four thermochemical dipoles including each an evaporator-condenser assembly and a reactor connected by means for circulating a gas G therebetween and means for interrupting the circulation of G. The reactors provide reversible phenomena between G and a liquid or solid, and the evaporators-condensers provide a gas-liquid phase change of G; the reactors are provided with means for mutual heat exchange and means for controlling the heat exchange; the thermochemical phenomena in the dipoles may be identical or different.