Pictured is a standard JTS 25DIAC (25 ton dual circuit air-cooled) chiller with an integrated economizer installed at the Medical College of Wisconsin. Economizers, sometimes called fluid coolers or free coolers, use low ambient temperatures to cool the glycol water mixture instead of using the compressors. When the ambient temperatures is less than the set point of the chiller, the eoonomizer (condenser coils/ fan) do the work. This saves on energy in the winter months and also increases the lifespan of the compressors.