TFC units differ from traditional chillers by the addition of a finned air/water heat exchange battery (free-cooler), a 3-way water flow modulating valve, pressure transducers and temperature probes supplying data to a microprocessor with unique software which then governs the operating parameters of the system. By exploiting low ambient air temperatures to cool water circulating through the finned heat exchange battery (free-cooler), cold water can be produced at minimal cost resulting in considerable energy savings.