Product

Heat Exchangers

History & Benefits

Copper Heat Exchangers

 

Heat exchangers using copper and its alloys have evolved along with heat transfer technologies over the past several hundred years. Copper condenser tubes were first used in 1769 for steam engines. Initially, the tubes were made of unalloyed copper. By 1870, Muntz metal, a 60% Cu-40% Zn brass alloy, was used for condensers in seawater cooling. Admiralty metal, a 70% Cu-30% Zn yellow brass alloy with 1% tin added to improve corrosion resistance, was introduced in 1890 for seawater service.[2] By the 1920s, a 70% Cu-30% Ni alloy was developed for naval condensers. Soon afterwards, a 2% manganese and 2% iron copper alloy was introduced for better erosion resistance. A 90% Cu-10% Ni alloy first became available in the 1950s, initially for seawater piping. This alloy is now the most widely used copper-nickel alloy in marine heat exchangers.

Today, steam, evaporator, and condenser coils are made from copper and copper alloys. These heat exchangers are used in air conditioning and refrigeration systems, industrial and central heating and cooling systems, radiators, hot water tanks, and under-floor heating systems.

Copper-based heat exchangers can be manufactured with copper tube/aluminium fin, cupro-nickel, or all-copper constructions. Various coatings can be applied to enhance corrosion resistance of the tubes and fins.

Heat exchangers are devices that transfer heat in order to achieve desired heating or cooling. An important design aspect of heat exchanger technology is the selection of appropriate materials to conduct and transfer heat fast and efficiently.

Copper alloys suc as has many desirable properties for thermally efficient and durable heat exchangers. First and foremost, copper is an excellent conductor of heat. This means that copper’s high thermal conductivity allows heat to pass through it quickly. Other desirable properties of copper in heat exchangers include its corrosion resistance, biofouling resistance, maximum allowable stress and internal pressure, creep rupture strength, fatigue strength, hardness, thermal expansion, specific heat, antimicrobial properties, tensile strength, yield strength, high melting point, alloyability, ease of fabrication, and ease of joining.

The combination of these properties enable copper to be specified for heat exchangers in industrial facilities, HVAC systems, vehicular coolers and radiators, and as heat sinks to cool computers, disk drives, televisions, computer monitors, and other electronic equipment. Copper is also incorporated into the bottoms of high-quality cookware because the metal conducts heat quickly and distributes it evenly. (Click here for more – Wikipedia)

 

Corrosion resistance is essential in heat transfer applications where fluids are involved, such as in hot water tanks, radiators, etc. The only affordable material that has similar corrosion resistance to copper is stainless steel. However, the thermal conductivity of stainless steel is 1/30th that of copper. Aluminium tubes are not suitable for potable or untreated water applications because it corrodes at pH

Protective films can be applied to the inner surface of copper alloy tubes to increase corrosion resistance. For certain applications, the film is composed of iron. In power plant condensers, duplex tubes consisting of an inner titanium layer with outer copper-nickel alloys are employed. This enables the use of copper’s beneficial mechanical and chemical properties (e.g., stress corrosion cracking, ammonia attack) along with titanium’s excellent corrosion resistance. A duplex tube with inner aluminium brass or copper-nickel and outer stainless or mild steel can be used for cooling in the oil refining and petrochemical industries. – (Wikipedia)

 

Copper and copper-nickel alloys have a high natural resistance to biofouling relative to alternative materials. Other metals used in heat exchangers, such as steel, titanium and aluminium, foul readily. Protection against biofouling, particularly in marine structures, can be accomplished over long periods of time with copper metals.

 

Copper-nickel alloys have been proven over many years in sea water pipework and other marine applications. These alloys resist biofouling in open seas where they do not allow microbial slime to build up and support macrofouling.

Researchers attribute copper’s resistance to biofouling, even in temperate waters, to two possible mechanisms: 1) a retarding sequence of colonization through slow release of copper ions during the corrosion process, thereby inhibiting the attachment of microbial layers to marine surfaces; and/or, 2) separating layers that contain corrosive products and the larvae of macro-encrusting organisms. The latter mechanism deters the settlement of pelagic larval stages on the metal surface, rather than killing the organisms. – (Wikipedia)