Sea water cooled HVAC systems, also known as Sea Water Air Conditioning (SWAC), utilize naturally cold deep ocean water to cool buildings. Instead of using conventional air conditioning methods, SWAC systems pump cold water from the ocean depths through a heat exchanger to cool fresh water, which is then circulated to cool the building's air. This approach reduces energy consumption and reliance on traditional refrigerants, offering a more sustainable and often more cost-effective solution, especially in coastal areas with access to deep ocean water.

Air-cooled refers to a method of heat rejection where a refrigerant transfers heat to the surrounding air using fans, rather than relying on water as a cooling medium. Essentially, air-cooled systems use ambient air to cool down the refrigerant, which then absorbs heat from the space being conditioned.