Abstract: A heat exchanger includes an elastically flexible liner formed as an elongated hose having an open end and a closed end. The elongated hose defines an inner surface. The heat exchanger also includes a plurality of longitudinal sleeves substantially disposed within the elongated hose. Each of the plurality of longitudinal sleeves has a proximate end defining an inlet opening and a distal end defining an outlet opening. When a fluid is pumped from the inlet openings of the plurality of longitudinal sleeves to the outlet openings of the plurality of longitudinal sleeves, the fluid passes from the outlet openings into the closed end of the elongated hose, along the inner surface of the elongated hose, and out through the open end of the elongated hose.