The object of the invention is an hydraulic setting composition comprising: an aggregate comprising calcium carbonate; an aggregate comprising silica; alkaline hydroxide; and a suitable quantity of water, characterized in that it contains less than 20% by weight of component and that the sum of the content of cations other than Si and Ca of components a) and b) is less than 10%. The internal heat exchanger 6 has a triple tube structure in which a heat insulator 15 is provided between a high-pressure medium passage 13 and a low-pressure medium passage 14. The battery supplies electrical power to an electrical distribution bus in the docking station.