Below is a list of Heat Recovery Systems manufacturers from Milwaukee, Wisconsin. A heat recovery system, or heat exchanger system, is any method that recaptures heat generated as the byproduct of one process and reuses it for another process. As energy costs continue to rise, heat recovery is becoming more popular in industrial, commercial and residential settings. Heat exchangers used in recovery systems are categorized by their general construction with plate, air-cooled and shell and tube being the three most common groupings.