HEAT-TRANSFER-FLUID HEAT EXCHANGER WITH OPTIMISED ASSEMBLY, AND THERMAL ENERGY STORAGE DEVICE USING A PHASE CHANGE MATERIAL AND COMPRISING SAID EXCHANGER

The invention relates to a heat exchanger (1) comprising a heat transfer fluid, which can at least partially extend down into a tank (14) containing a phase change material (PCM) (13), said heat exchanger comprising: a plurality of tubes (2), each tube (2) having a first end (3) that can be arranged in the upper part of the exchanger (1) and a second end (4) that can be arranged in the lower part of the exchanger (1); a distributor (5) establishing a fluid communication between the first ends (3); a manifold (6) establishing a fluid communication between the second ends (4), said distributor (5) comprising an open pipe (7) for supplying or discharging the heat transfer fluid to/from the exchanger (1), said manifold (6) comprising an open pipe (8) for supplying or discharging the heat transfer fluid to/from the exchanger (1). The heat exchanger is characterised in that the heat transfer fluid is a two-phase fluid with a liquid state and a gaseous state that can flow through the exchanger (1), and in that the pipe (8) of the manifold (6) and the pipe (7) of the distributor (5) are configured to open at the upper part of the exchanger (1). The invention is suitable for use in thermal storage systems (TSS) using phase change materials (PCM). More specifically, the invention relates to the integration of a thermal storage system into concentrating solar power systems, for example for direct steam generation power plants, or the recovery of fatal heat from industry.