Abstract: A heat exchanger system suitable for facilitating the economical cooling of hot fluids in the vicinity of a body of water. The preferred embodiment of the present invention contemplates a vertical, or combination vertical and horizontal thermosyphonic, passive, heat exchanger column situated in a body of water and enveloped by a caisson or the like, and configured to facilitate, through percolation, enhanced circulation of seawater therethrough and effecting significant cooling of a hot, hydrocarbon well stream, or other hot fluid in the vicinity of a body of water. A vertically situated bundle of tubes forms the heat exchanger, which may include a system of staggered baffles to direct the flow of cooling seawater to effect even temperature distribution throughout the tube bundle. The present system further teaches a system for cooling high pressure, hot fluids as may be found in a deep hydrocarbon reserve offshore, utilizing a the vertical heat exchange column of the present invention.