At its core, a chiller is a refrigeration system designed to remove heat through a vapor-compression, absorption, or adsorption refrigeration cycle. The primary objective is to cool a fluid or dehumidify air in an industrial or commercial setting. Simply put, a chiller is a machine that cools things down. More @Wikipedia
Hover over any link to get a description of the article. Please note that search keywords are sometimes hidden within the full article and don't appear in the description or title.