Abstract: The particle-to-working fluid heat exchanger is a particle-to-working fluid counter-flow direct contact heat exchanger formed from a heat exchange chamber having opposed upper and lower ends. A diameter of the heat exchange chamber decreases from the upper end to the lower end, with a fluid inlet positioned adjacent the lower end for receiving a stream of fluid. The stream of fluid is tangentially and upwardly directed within the heat exchange chamber. The heat exchange chamber also has a fluid outlet positioned adjacent the upper end thereof. A distribution manifold for the heat exchange chamber produces a plurality of streams of heated particles which exchange thermal energy with the stream of fluid to generate a stream of heated fluid and a volume of cooled particles. A solar power generator, in the form of a solar tower, is further provided, which incorporates the particle-to-working fluid counter-flow direct contact heat exchanger.