How hybrid air coolers work

HYAC Single Zone

Working principle of HYAC SZ

An Alfa Laval HYAC SZ has one cooling zone. When the ambient temperature is low, the HYAC system operates as a traditional air-cooled heat exchanger; the hot medium flows through a bundle of finned tubes, and a fan draws cool air over the tube surfaces to cool the medium inside.

When the ambient temperature rises above a certain level, wet cooling mode is activated, and water is sprayed on the tubes. The heat from the hot medium evaporates the water on the tube surfaces, which increases cooling significantly.

Since wet cooling only is engaged when required, substantial amounts of water is saved compared to a cooling tower solution. And compared to an air-cooled heat exchanger, a HYAC system is much smaller and has fewer fans, saving both CAPEX and OPEX.

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HYAC Dual Zone

Working principle of HYAC DZ

An Alfa Laval HYAC DZ has two cooling zones. The first is a traditional air-cooled heat exchanger, and the second is an evaporative cooler, very similar to a standard Alfa Laval WSAC.

During normal operation, both zones are always engaged. The hot medium is first cooled in the air-cooler zone, approaching the dry bulb temperature, and is then further cooled in the second zone, reaching a final temperature close to the wet bulb temperature.

This two-stage cooling results in a much higher cooling capacity and lower output temperature than for traditional air-cooled heat exchangers. It also saves water compared to standard evaporative cooling systems and cooling towers. In addition, the dual zone design also leads to less visible plume.

This makes Alfa Laval HYAC systems the perfect solution for expansions where increased cooling and low water consumption are required and where space is limited. Thanks to its high cooling efficiency, a HYAC system is much smaller than a comparable air-cooler solution, resulting in lower CAPEX and OPEX.

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