We describe the development of a new type of heat exchanger. This heat exchanger operates using reverse thermosiphon action and consists of a self-acting and self-controlled liquid circulation loop with heat transfer in a downward direction, opposite to the direction of natural convection. This process moves a heat-carrying hot liquid downwards with the help of local heat transferred through the loop. This flow loop is partly filled with liquid and the upper part of the loop contains vapour from the liquid heat-carrier. The pressure difference in the saturated vapour is used to move the heated liquid downwards. The principles of action and the possibility of developing such a device using laboratory experimental methods are presented.