An air-cooled chiller operates on a simple vapour-compression refrigeration cycle to cool water, which is then pumped throughout a facility to provide air conditioning or process cooling. The core difference lies in how it rejects heat. Instead of using water and an external cooling tower, an air-cooled chiller utilizes a bank of high-powered, propeller-style condenser fans. These fans blow ambient outdoor air directly across a finned condenser coil, rapidly dissipating heat into the atmosphere. Because the entire heat rejection system is self-contained within the chiller unit, it requires zero external water source for cooling.