The heat exchanger of the present invention provides an indirect evaporative heat exchange section and a direct evaporative heat exchange section. Evaporative liquid of uniform temperature is injected downward into the indirect section to indirectly exchange sensible heat with the hot fluid stream flowing in the series of enclosed circuits that make up the indirect evaporative heat exchange section. The evaporative fluid descends through the entire indirect heat exchange section and then is distributed across the fill media in the direct evaporation heat exchange section to absorb and cool the heat. Separate streams of ambient cooling air are simultaneously introduced into each heat exchange section to evaporatively cool the evaporating liquid flowing inside each section. The water cooled in the direct heat exchange section is collected and mixed in the reservoir, resulting in a uniform temperature and redistribution. The initial uniform temperature of the cooling water is the most important control factor in maximizing the overall performance and uniformity of the cooling tower and indirect heat exchange section. The indirect heat exchange section is composed of a series of circuits of constant intervals having a continuous S-shape, in which internal fluid to be cooled flows upwards with a uniform flow rate and temperature between the circuits. As the water descends, the sensible heat is exchanged indirectly with a uniform fluid between the circuits along the vertical and horizontal heights of the indirect heat exchange section. An additional gain that can be obtained from the heat exchange and the uniformity of performance between the circuits is realized when the cooling air stream flowing through the indirect heat exchange section is parallel or co-directional with the coolant flow. The device can be used as a fluid cooler, evaporative condenser, or wet air cooler.
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