Abstract: The evaporator comprises a) a chamber (12) made of a porous material with an inlet for a heat exchanging fluid in liquid form, b) a shell (9) in which is located said chamber (12) to define around it, a chamber (15) for collecting said fluid in vapor form, said shell (9) having an outlet by which the vapor collected in said chamber (15) is evacuated. It further comprises a tube (22) which extends through the whole internal space of the chamber (12) with a porous wall, from one end (24) of the tube constituting the chamber (12) inlet for the heat exchanging fluid, said tube (22) being pierced over its whole length with holes (33) for injecting the heat exchanging liquid into the chamber (12) wall.

Abstract: A hot source (A) contains one assembly comprised of at least one capillary evaporator (1A) and at least one condenser (2B) having condensation surfaces with a large curvature radius, and a cold source (B) containing an assembly of the same nature (1B, 2B). The condensers are interconnected by means of a steam conduit (3) and the capillary evaporators are interconnected by means of a liquid conduit (4) so as to form a closed circuit wherein circulates a metered fluid amount so that the complete evaporation takes place in the "hot" evaporators and the complete condensation takes place in the "cold" condensers, the other elements being then inactive. The system is reversible and, consequently, interesting gains of weight and room can be achieved for a spatial utilization.