The key difference lies in the heat transfer coefficient. Generally, because the heat transfer film coefficient of the condensation process is much greater than that of a cooling process without phase change, the overall heat transfer coefficient of a condenser is usually much larger than that of a simple cooling process, sometimes by an order of magnitude. Condensers are generally used to cool gases into liquids, and their outer shells are usually very hot. Coolers, on the other hand, are a broader concept, primarily referring to heat exchangers that convert hot cold media to room temperature or a slightly lower temperature.

Regarding series heat exchangers: If there are two heat exchangers in series, how do you distinguish between a condenser and a cooler? Generally, the one with the larger inlet and smaller outlet is the condenser, while those with the same inlet diameter are usually coolers. This is easily identifiable from the shape of the equipment.

When two heat exchangers are connected in series, with the same mass flow rate, because latent heat is much higher than sensible heat, and assuming the heat exchanger types are the same, the one with the larger heat exchange area is the condenser. That is, the larger one should be the condenser.

A condenser is a heat exchanger that absorbs heat from a gaseous material, causing it to condense into a liquid state. This involves a phase change, and the change is quite significant. The cooling medium can absorb heat directly or indirectly from the medium being condensed, but there is no phase change. Plate coolers only lower the temperature of the medium being cooled, without a phase change. In a plate cooler, the cooling medium and the medium being cooled generally do not come into direct contact; heat transfer is achieved through tubes or a jacket. Furthermore, plate coolers are generally more structurally complex than condensers.