Abstract: A condensing heat exchanger is formed of norbornene polymer, preferably a norbornene homopolymer or copolymer. A plurality of norbornene polymer pellets are melted and extruded to form a first tube. The tube is then blow molded into a mold. A second extruded tube is also blow molded into a U-shape, and the first tube is positioned in the U-shaped opening to form a cell. The ends of the cells are attached to a holding plate by thermal adhesion or heating and flaring. Norbornene polymer possesses exceptional thermal resistance to the high temperature flue vent gases and has physical and chemical resistance to the acidic condensate formed by the condensing heat exchanger.

Abstract: A thin coating of a solution containing a low surface energy material is applied on the inner surface of tubing of a condenser or an evaporator of an air conditioning system. The solution is run through the tubing of the heat exchanger and drained. After drying, a monomolecular layer of the low surface energy material in solution remains on the inner surface of the tubing. A polymer with a lower surface energy and chemical and thermal resistance is employed, such as silane, fluorocarbons, polyetheretherketon (PEEK) and polysulfone. The thin coating of the lower surface energy material in solution prevents lubricating oil from the compressor which mixes with the refrigerant from wetting over the inner surface of the tubing, encouraging the formation of oil droplets. By preventing the build up of lubricating oil, heat transfer is improved.

Abstract: A thermoplastic polymer film is directly extruded onto the heated surface of a metal condensing heat exchanger. Any thermoplastic polymer capable of being adhered to the metal surface of the condensing heat exchanger can be utilized. Preferably, the thermoplastic polymer is a polyester, a polyolefin with an added maleate or tackifier to ensure adhesion, polyetherimide, polyethersulfone, polysufone or polyimide. The thermoplastic film must be resistant to the conditions of the condensing heat exchanger, such as the high temperature flue vent gases and the acidic condensate formed from condensation.

Abstract: A film is adhered to a metal plate of a condensing heat exchanger by a cured layer of silicone RTV elastomer to prevent corrosion of the condensing heat exchanger. A layer of solid silicon RTV elastomer including an organosilicone functional group is applied on the pretreated metal surface. The metal plate is heated and a protective film is then applied. The film is adhered to the surface of the metal sheet by curing the layer of silicone RTV elastomer with the water. The water reacts with the organosilicone functional groups on the silicone RTV elastomer layer, cross-linking the organosilicone functional groups to create an adhesive surface which adheres the film to the surface.

Abstract: A condensing heat exchanger is formed of norbornene polymer, preferably a norbornene homopolymer or copolymer. A plurality of norbornene polymer pellets are melted and extruded to form a first tube. The tube is then blow molded into a mold. A second extruded tube is also blow molded into a U-shape, and the first tube is positioned in the U-shaped opening to form a cell. The ends of the cells are attached to a holding plate by thermal adhesion or heating and flaring. Norbornene polymer possesses exceptional thermal resistance to the high temperature flue vent gases and has physical and chemical resistance to the acidic condensate formed by the condensing heat exchanger.

Abstract: A thin coating of a solution containing a low surface energy material is applied on the inner surface of tubing of a condenser or an evaporator of an air conditioning system. The solution is run through the tubing of the heat exchanger and drained. After drying, a monomolecular layer of the low surface energy material in solution remains on the inner surface of the tubing. A polymer with a lower surface energy and chemical and thermal resistance is employed, such as silane, fluorocarbons, polyetheretherketon (PEEK) and polysulfone. The thin coating of the lower surface energy material in solution prevents lubricating oil from the compressor which mixes with the refrigerant from wetting over the inner surface of the tubing, encouraging the formation of oil droplets. By preventing the build up of lubricating oil, heat transfer is improved.

Abstract: A film is adhered to a metal plate of a condensing heat exchanger by a cured layer of silicone RTV elastomer to prevent corrosion of the condensing heat exchanger. A layer of solid silicon RTV elastomer including an organosilicone functional group is applied on the pretreated metal surface. The metal plate is heated and a protective film is then applied. The film is adhered to the surface of the metal sheet by curing the layer of silicone RTV elastomer with the water. The water reacts with the organosilicone functional groups on the silicone RTV elastomer layer, cross-linking the organosilicone functional groups to create an adhesive surface which adheres the film to the surface.

Abstract: A primary heat exchanger of a condensing furnace or a single heat exchanger of a mid-efficiency furnace is electrochemically coated with a coating of copper metal. The copper coating is oxidized with an aqueous oxidizing alkaline solution to form a matte black layer of cupric oxide. As the layer of cupric oxide is black, the layer has a high emissivity and emits more heat, increasing the efficiency of the primary heat exchanger. Alternatively, iron can be electrochemically coated on the primary heat exchanger and oxidized to black magnetite to increase emissivity.

Abstract: Cured ethylene terpolymer attaches a film to the metal surface of a condensing heat exchanger of a condensing furnace to prevent corrosion of the condensing heat exchanger. After applying a layer of ethylene terpolymer to the metal surface of the condensing heat exchanger, a film is positioned on the layer. Water reacts with the organosilicone functional groups on the ethylene terpolymer chain, cross-linking the organosilicone functional groups and adhering the film to the surface of condensing heat exchanger. The water is provided in the film or is added by an external source. Preferably, the film is polar to encourage adhesion of the water to the film and encourage cross-linking of the organosilicone functional groups.

Abstract: A thermoplastic polymer film is directly extruded onto the heated surface of a metal condensing heat exchanger. Any thermoplastic polymer capable of being adhered to the metal surface of the condensing heat exchanger can be utilized. Preferably, the thermoplastic polymer is a polyester, a polyolefin with an added maleate or tackifier to ensure adhesion, polyetherimide, polyethersulfone, polysufone or polyimide. The thermoplastic film must be resistant to the conditions of the condensing heat exchanger, such as the high temperature flue vent gases and the acidic condensate formed from condensation.