Chillers use refrigerant gas and a vapor compressor to enable settings down to (or below) the ambient air temperature. External liquid coolant is circulated through a chilled reservoir or heat exchanger, which is isolated from the sealed refrigerant line. Koolance's performance ratings for chillers use a 0°C delta-T, meaning the quantity of heat is being dissipated while the liquid is kept at the ambient air temperature (of 25°C). These products can operate below ambient with lower heat loads and set-points.
