CuproBraze is a copper-alloy heat exchanger technology for high-temperature and pressure environments such as those in modern

diesel engine The diesel engine, named after the German engineer Rudolf Diesel, is an internal combustion engine in which Combustion, ignition of diesel fuel is caused by the elevated temperature of the air in the cylinder due to Mechanics, mechanical Compr ...

s.Partanen, Juho (2011). Hot property: Heat exchangers that optimize product reliability, decrease lifecycle costs and improve profitability are just the ticket for increasing the lifespan and performance of off-highway machinery; Industrial Vehicle Technology; March 2011; http://viewer.zmags.com/services/DownloadPDF The technology, developed by the International Copper Association (ICA), is licensed for free to heat exchanger manufacturers around the world. Applications for CuproBraze include

charge air cooler An intercooler is a heat exchanger used to cool a gas after compression. Often found in turbocharged engines, intercoolers are also used in air compressors, air conditioners, refrigeration and gas turbines. Internal combustion engines Most ...

radiator A radiator is a heat exchanger used to transfer thermal energy from one medium to another for the purpose of cooling and heating. The majority of radiators are constructed to function in cars, buildings, and electronics. A radiator is always a ...

oil cooler An oil is any nonpolar chemical substance that is composed primarily of hydrocarbons and is hydrophobic (does not mix with water) and lipophilic (mixes with other oils). Oils are usually flammable and surface active. Most oils are unsaturate ...

climate control Heating, ventilation, and air conditioning (HVAC ) is the use of various technologies to control the temperature, humidity, and purity of the air in an enclosed space. Its goal is to provide thermal comfort and acceptable indoor air quality. H ...

systems, and heat transfer cores.Duensing, Lauren (2006) Develop efficient heat-transfer systems, Modern Metals, March 2006

/ref> CuproBraze is suited for charge air coolers and radiators in heavy industry where

machinery A machine is a physical system that uses power to apply forces and control movement to perform an action. The term is commonly applied to artificial devices, such as those employing engines or motors, but also to natural biological macromolec ...

must operate for long periods of time under harsh conditions without failures. The technology is intended for

off-road vehicle An off-road vehicle (ORV), also known as an off-highway vehicle (OHV), overland vehicle or adventure vehicle, is a type of transportation specifically engineered to navigate unpaved roads and surfaces. These include trails, forest roads, and ...

truck A truck or lorry is a motor vehicle designed to transport freight, carry specialized payloads, or perform other utilitarian work. Trucks vary greatly in size, power, and configuration, but the vast majority feature body-on-frame construct ...

bus A bus (contracted from omnibus, with variants multibus, motorbus, autobus, etc.) is a motor vehicle that carries significantly more passengers than an average car or van, but fewer than the average rail transport. It is most commonly used ...

es, industrial

engine An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy. Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power ge ...

s, generators,

locomotive A locomotive is a rail transport, rail vehicle that provides the motive power for a train. Traditionally, locomotives pulled trains from the front. However, Push–pull train, push–pull operation has become common, and in the pursuit for ...

s, and

military equipment A military, also known collectively as armed forces, is a heavily armed, highly organized force primarily intended for warfare. Militaries are typically authorized and maintained by a sovereign state, with their members identifiable by a d ...

. It is also used for

light truck Light truck or light-duty truck is a US classification for vehicles with a gross vehicle weight up to and a payload capacity up to . Similar goods vehicle classes in the European Union, Canada, Australia, and New Zealand are termed light ...

SUV A sport utility vehicle (SUV) is a car classification that combines elements of road-going passenger cars with features from off-road vehicles, such as raised ground clearance and four-wheel drive. There is no commonly agreed-upon definition ...

s and

passenger cars A car, or an automobile, is a motor vehicle with wheels. Most definitions of cars state that they run primarily on roads, Car seat, seat one to eight people, have four wheels, and mainly transport private transport#Personal transport, peopl ...

with special needs.Asia Hot on New Cooling Technology: Cooling Systems: New engine requirements mean manufacturers are changing to copper and brass for cooling systems; Automotive Engineering International, February 2005CuproBraze: Advanced heat-exchanger technolog

/ref> Compared with previous heat exchanger models CuproBraze creates new materials for heat exchanger parts that have previously been made of soldered copper/brass plate fin, soldered copper brass serpentine fin, and brazed aluminum serpentine fin to suit more demanding applications. Aluminum heat exchangers are viable and economical for

car A car, or an automobile, is a motor vehicle with wheels. Most definitions of cars state that they run primarily on roads, seat one to eight people, have four wheels, and mainly transport people rather than cargo. There are around one billio ...

s, light

s, and other light-duty applications. However, they are not amenable for environments characterized by high operating

temperature Temperature is a physical quantity that quantitatively expresses the attribute of hotness or coldness. Temperature is measurement, measured with a thermometer. It reflects the average kinetic energy of the vibrating and colliding atoms making ...

humidity Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation (meteorology), precipitation, dew, or fog t ...

vibration Vibration () is a mechanical phenomenon whereby oscillations occur about an equilibrium point. Vibration may be deterministic if the oscillations can be characterised precisely (e.g. the periodic motion of a pendulum), or random if the os ...

salt In common usage, salt is a mineral composed primarily of sodium chloride (NaCl). When used in food, especially in granulated form, it is more formally called table salt. In the form of a natural crystalline mineral, salt is also known as r ...

corrosive Corrosion is a natural process that converts a refined metal into a more chemically stable oxide. It is the gradual deterioration of materials (usually a metal) by chemical or electrochemical reaction with their environment. Corrosion engine ...

air An atmosphere () is a layer of gases that envelop an astronomical object, held in place by the gravity of the object. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A stellar atmosph ...

, and

air pollution Air pollution is the presence of substances in the Atmosphere of Earth, air that are harmful to humans, other living beings or the environment. Pollutants can be Gas, gases like Ground-level ozone, ozone or nitrogen oxides or small particles li ...

. In these environments, the additional

tensile strength Ultimate tensile strength (also called UTS, tensile strength, TS, ultimate strength or F_\text in notation) is the maximum stress that a material can withstand while being stretched or pulled before breaking. In brittle materials, the ultimate ...

, durability, and

corrosion resistance Corrosion is a natural process that converts a refined metal into a more chemically stable oxide. It is the gradual deterioration of materials (usually a metal) by chemical or electrochemical reaction with their environment. Corrosion engine ...

that CuproBraze technology provides are useful. The CuproBraze technology uses

brazing Brazing is a metal-joining process in which two or more metal items are joined by melting and flowing a filler metal into the joint, with the filler metal having a lower melting point than the adjoining metal. Brazing differs from welding in ...

instead of

soldering Soldering (; ) is a process of joining two metal surfaces together using a filler metal called solder. The soldering process involves heating the surfaces to be joined and melting the solder, which is then allowed to cool and solidify, creatin ...

to join copper and brass radiator components. The heat exchangers are made with anneal-resistant

copper Copper is a chemical element; it has symbol Cu (from Latin ) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orang ...

and

brass Brass is an alloy of copper and zinc, in proportions which can be varied to achieve different colours and mechanical, electrical, acoustic and chemical properties, but copper typically has the larger proportion, generally copper and zinc. I ...

alloys. The tubes are fabricated from brass strip and coated with a brazing filler material in form of a powder-based paste or an

amorphous brazing foil An amorphous brazing foil (ABF) is a form of eutectic amorphous metal that serves as a filler metal in brazing operations. ABFs are composed of various transition metals (including nickel, iron, and copper) blended with metalloids like silicon, b ...

is laid between the tube and fin. There is another method of coating the tube in-line on the tube mill. This is done using the twin wire-arc spray process where the wire is the braze alloy, deposited on the tube as it is being manufactured at 200-400 fpm. This saves one process step of coating the tube later. The coated tubes, along with copper fins, headers and side supports made of brass, are fitted together into a core assembly which is brazed in a furnace. The technology enables brazed serpentine fins to be used in copper-brass heat exchanger designs. The benefits include tougher joints.

Performance properties

CuproBraze has better than other materials in several aspects, as shown in the table below.

Thermal performance

The ability to withstand elevated temperatures is essential in high-heat applications.

Aluminum Aluminium (or aluminum in North American English) is a chemical element; it has chemical symbol, symbol Al and atomic number 13. It has a density lower than that of other common metals, about one-third that of steel. Aluminium has ...

alloys are challenged at higher temperatures due to their lower

melting point The melting point (or, rarely, liquefaction point) of a substance is the temperature at which it changes state of matter, state from solid to liquid. At the melting point the solid and liquid phase (matter), phase exist in Thermodynamic equilib ...

s. The

yield strength In materials science and engineering, the yield point is the point on a stress–strain curve that indicates the limit of elastic behavior and the beginning of plastic behavior. Below the yield point, a material will deform elastically and w ...

of aluminum is compromised above 200 °C. Problems with fatigue cracking are exacerbated at elevated temperatures. CuproBraze heat exchangers can operate correctly under temperatures of 290°C and above. Anneal-resistant copper and brass strip ensure that radiator cores maintain their strength without softening, despite exposures to high brazing temperatures.

Heat transfer efficiency

Cooling efficiency is a measure of heat rejection from a given space by a heat exchanger.CuproBraze Efficiency (Design Criteria Series): http://www.cuprobraze.com/pdf/Efficiency.pdf The overall

thermal efficiency In thermodynamics, the thermal efficiency (\eta_) is a dimensionless performance measure of a device that uses thermal energy, such as an internal combustion engine, steam turbine, steam engine, boiler, furnace, refrigerator, ACs etc. For ...

of a heat exchanger core depends on many factors, such as

thermal conductivity The thermal conductivity of a material is a measure of its ability to heat conduction, conduct heat. It is commonly denoted by k, \lambda, or \kappa and is measured in W·m−1·K−1. Heat transfer occurs at a lower rate in materials of low ...

of fins and tubes; strength and weight of the fins and tubes; spacing, size, thickness and shape of fins and tubes;

velocity Velocity is a measurement of speed in a certain direction of motion. It is a fundamental concept in kinematics, the branch of classical mechanics that describes the motion of physical objects. Velocity is a vector (geometry), vector Physical q ...

of the air passing through the core; and other factors. The main performance criterion for heat exchangers is cooling efficiency. Heat exchanger cores made from copper and brass can reject more heat per unit volume than any other material. This is why copper-brass heat exchangers generally have a greater cooling efficiency than alternate materials. Brazed copper-brass heat exchangers are also more rugged than soldered copper-brass and alternate materials, including brazed aluminum serpentine. Air pressure drop is a factor of heat exchanger design. A heat exchanger core with a smaller air pressure drops from the front to the back of the core (i.e., from the windward to the leeward side in a wind tunnel test) is more efficient. Air pressure drops typically are 24% less for CuproBraze versus aluminum heat exchangers. This advantage, responsible for a 6% increase in heat rejection, contributes to CuproBraze's overall greater efficiency.CuproBraze: Efficient, durable, sustainable, CuproBraze heat exchanger (brochure): http://www.cuprobraze.com/documents/EfficientdurablesustainableCuproBrazeheatexchanger.pdf Since copper's thermal conductivity is higher than aluminum, copper has a higher capacity to dissipate heat. By using thinner material gauges in combination with higher fin density, heat dissipation capacity with CuproBraze can be increased with air pressure drops still at reasonable levels.

Size

Due to its high heat transfer efficiency, CuproBraze has an efficient heating effect. This is because the same heat rejection level can be achieved with a smaller-sized core. Hence, a significant reduction in frontal area and volume is achievable with CuproBraze versus other materials.

Strength and durability

Three new alloys were developed to enhance the strength and durability of CuproBraze heat exchangers: 1) an anneal-resistant fin material that maintains its strength after brazing; 2) an anneal-resistant tube alloy that retains its fine grain structure after brazing and provides ductility and fatigue strength in the brazed heat exchanger core; and 3) the brazing alloy.CuproBraze: Durability and reliability (Technology Series); http://www.cuprobraze.com/documents/3Durabilityandreliability.pdf Brazing at 650 °C creates a joint that is stronger than a soldered joint and comparable in strength to a welded joint. Unlike welding, brazing does not melt the base metals. Therefore, brazing is better for joining dissimilar alloys. CuproBraze has more strength at elevated temperatures than soldered copper-brass or aluminum. Due to the lower

thermal expansion Thermal expansion is the tendency of matter to increase in length, area, or volume, changing its size and density, in response to an increase in temperature (usually excluding phase transitions). Substances usually contract with decreasing temp ...

of copper versus aluminum, there is less

thermal stress In mechanics and thermodynamics, thermal stress is mechanical stress created by any change in temperature Temperature is a physical quantity that quantitatively expresses the attribute of hotness or coldness. Temperature is measurement, m ...

during the manufacturing of CuproBraze and in its use as a heat exchanger. CuproBraze heat exchangers have stronger tube-to-header joints than other materials. These braze joints are the very important in heat exchangers and must be leak-free. CuproBraze also has higher tolerances to internal pressures because its thin-gauge high strength materials provide stronger support for the tubes. The material is also less sensitive to bad coolants than aluminum heat exchangers. Test results demonstrate a much longer fatigue life for CuproBraze joints compared to similar soldered copper-brass or brazed aluminum joints.CuproBraze Durability (design criteria series): http://www.cuprobraze.com/pdf/Durability.pdf Stronger joints allow for the use of thinner fins and new radiator and cooler designs. The copper fins are not easily bent when dirty radiators are washed with high pressure water. Anticorrosive coatings further improve strength and resistance against humidity, sand erosion, and stone impingement on copper fins. For further information, see: CuproBraze: Durability and reliability (Technology Series): and CupropBraze durability (design criteria series).

Emissions

New legislation in

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

and the

U.S. The United States of America (USA), also known as the United States (U.S.) or America, is a country primarily located in North America. It is a federal republic of 50 states and a federal capital district, Washington, D.C. The 48 contiguous ...

call for strong reductions in NO_X and

particulate emissions Particulate matter (PM) or particulates are microscopic particles of solid or liquid matter suspended in the air. An ''aerosol'' is a mixture of particulates and air, as opposed to the particulate matter alone, though it is sometimes defined ...

from

diesel engines The diesel engine, named after the German engineer Rudolf Diesel, is an internal combustion engine in which ignition of diesel fuel is caused by the elevated temperature of the air in the cylinder due to mechanical compression; thus, the die ...

used in

es,

power plant A power station, also referred to as a power plant and sometimes generating station or generating plant, is an industrial facility for the electricity generation, generation of electric power. Power stations are generally connected to an electr ...

s, and other heavy equipment.Bo Svensson, 2006. Cool technology to help meet emissions targets: Diesel Progress International Edition; July–August 2006, http://www.cuprobraze.com/pdf/inthenews_diesel.pdf These goals can in part be accomplished by using cleaner-performing turbocharged diesel engines and

s. Turbocharging enables better power outputs, and charge air coolers allow power to be produced with more efficiency by reducing the temperature of the air charge entering the engine, thereby increasing its density. The charge air cooler, located between the turbocharger and the engine air inlet manifold, is an air-to-air heat exchanger. It reduces the inlet air temperatures of turbocharged diesel engines from 200 °C to 45 °C while increasing inlet air densities to increase engine efficiencies. Even higher inlet temperatures (246 °C or higher) and boost pressures may be necessary to comply with the emissions standards in the future. Present-day charge air cooler systems, based on aluminum alloys, experience durability problems at temperatures and pressures necessary to meet the U.S. Tier 4i standards for stationary and mobile engines.Brazed Copper-Brass Technology Flourishes in Diverse Applications; Automotive Exports; September 2009; Page 26-30 Published reports estimate that the average life of an aluminum charge air cooler is currently about 3,500 hours. Aluminum is near its upper technological limit to accommodate higher temperatures and thermal stress levels because the tensile strength of the metal declines rapidly at 150 °C and repetitive thermal cycling between 150 °C and 200 °C substantially weakens it. Thermal cycling creates weak spots in aluminum tubes, which in turn causes charge air coolers to fail. A potential option is to install stainless steel precoolers in aluminum charge air coolers, but limited space and the complexity of this solution is a tampering factor for this option. A CuproBraze charge air cooler can operate at temperatures as high as 290 °C without creep, fatigue, or other metallurgical problems.

Corrosion resistance

Exterior corrosion resistance in a heat exchanger is especially important in

coastal A coast (coastline, shoreline, seashore) is the land next to the sea or the line that forms the boundary between the land and the ocean or a lake. Coasts are influenced by the topography of the surrounding landscape and by aquatic erosion, su ...

areas,

humid Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation, dew, or fog to be present. Humidity depe ...

areas, polluted areas, and in

mining Mining is the Resource extraction, extraction of valuable geological materials and minerals from the surface of the Earth. Mining is required to obtain most materials that cannot be grown through agriculture, agricultural processes, or feasib ...

operations. Corrosion mechanisms of copper and aluminum alloys are different. CuproBraze tube contains 85% copper which provides much resistance against dezincification and

stress corrosion cracking Stress corrosion cracking (SCC) is the growth of crack formation in a corrosive environment. It can lead to unexpected and sudden failure of normally ductile metal alloys subjected to a tensile stress, especially at elevated temperature. SC ...

. The copper alloys tend to corrode uniformly over entire surfaces at known rates. This predictability of copper corrosion is important for proper maintenance management.FAQs about CuproBraze; Aluminum, on the other hand, is more likely to corrode locally by pitting, resulting eventually in holes. In accelerated corrosion tests, such as SWAAT for salt spray and marine conditions, CuproBraze performed better than aluminum. The corrosion resistance of CuproBraze is generally better than soft

solder Solder (; North American English, NA: ) is a fusible alloy, fusible metal alloy used to create a permanent bond between metal workpieces. Solder is melted in order to wet the parts of the joint, where it adheres to and connects the pieces aft ...

ed heat exchangers. This is because the materials in CuproBraze heat exchangers are of equal nobility, so galvanic differences are minimized. On soft soldered heat exchangers, the solder is less noble than fin and tube materials and can suffer from

galvanic attack Galvanic corrosion (also called bimetallic corrosion or dissimilar metal corrosion) is an electrochemical process in which one metal Corrosion, corrodes preferentially when it is in electrical contact with another, different metal, when both in ...

in corrosive environments.

Repairability

CuproBraze can be repaired with little complexities. This advantage of the technology is important in remote areas where spare parts may be limited. CuproBraze can be repaired with lead-free soft solder (for example 97%

tin Tin is a chemical element; it has symbol Sn () and atomic number 50. A silvery-colored metal, tin is soft enough to be cut with little force, and a bar of tin can be bent by hand with little effort. When bent, a bar of tin makes a sound, the ...

, 3%

) or with common

silver Silver is a chemical element; it has Symbol (chemistry), symbol Ag () and atomic number 47. A soft, whitish-gray, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal. ...

-containing brazing alloys.

Antimicrobial

Biofouling Biofouling or biological fouling is the accumulation of microorganisms, plants, algae, or small animals where it is not wanted on surfaces such as ship and submarine hulls, devices such as water inlets, pipework, grates, ponds, and rivers that ...

is often a problem in

HVAC Heating, ventilation, and air conditioning (HVAC ) is the use of various technologies to control the temperature, humidity, and purity of the air in an enclosed space. Its goal is to provide thermal comfort and acceptable indoor air quality. ...

systems that operate in warm, dark, and humid environments. The

antimicrobial An antimicrobial is an agent that kills microorganisms (microbicide) or stops their growth (bacteriostatic agent). Antimicrobial medicines can be grouped according to the microorganisms they are used to treat. For example, antibiotics are used aga ...

properties of CuproBraze alloys eliminate foul odors, thereby improving indoor air quality. CuproBraze is being investigated in mobile air conditioner units as a solution to bad odors from fungus and bacteria in aluminum-based heat exchange systems.

Uses

Russian OEMs, such as Kamaz and

Ural Automotive Plant The Urals Automotive Plant, an Open Stock Company, (Russian language, Russian: ''Ура́льский автомоби́льный заво́д, УралАЗ''; translit. Uralskiy Avtomobilnyi Zavod, UralAZ) is a major Russian manufacturer of off ...

, are using CuproBraze radiators and charge air coolers in heavy-duty trucks for off-highway and on-highway applications. Other manufacturers include UAZ and GAZ (

Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

) and MAZ (

Belarus Belarus, officially the Republic of Belarus, is a landlocked country in Eastern Europe. It is bordered by Russia to the east and northeast, Ukraine to the south, Poland to the west, and Lithuania and Latvia to the northwest. Belarus spans an a ...

). The Finnish Radiator Manufacturing Company, also known as FinnRadiator,FinnRadiator; http://www.finnradiator.com produces 95% of its radiators and charge air-coolers with CuproBraze for OEM manufacturers of off-road construction equipment. Nakamura Jico Co., Ltd. (

) manufactures CuproBraze heat exchangers for construction equipment, locomotives and on-highway trucks. Young Touchstone supplies CuproBraze radiators to MotivePower's diesel-powered commuter train locomotives in

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

Siemens AG Siemens AG ( ) is a German multinational technology conglomerate. It is focused on industrial automation, building automation, rail transport and health technology. Siemens is the largest engineering company in Europe, and holds the posit ...

Transportation Systems plans to use the technology for its Asia Runner

for

South Vietnam South Vietnam, officially the Republic of Vietnam (RVN; , VNCH), was a country in Southeast Asia that existed from 1955 to 1975. It first garnered Diplomatic recognition, international recognition in 1949 as the State of Vietnam within the ...

and other Asian markets.

Bombardier Transportation Bombardier Transportation was a Canadian rolling stock and rail transport manufacturer, with headquarters in Toronto and Berlin. It was one of the world's largest companies in the rail vehicle and equipment manufacturing and servicing industry. ...

heat exchangers cool transformer oil in electric-powered locomotives. These huge oil coolers have been used successfully in coal trains for

South African Railways Transnet Freight Rail is a Rail transport in South Africa, South African rail transport company, formerly known as Spoornet. It was part of the South African Railways and Harbours Administration, a state-controlled organisation that employed h ...

. Kohler Power Systems Americas, one of the largest users of diesel engines for power generation, adopted CuproBraze for diesel engine turbocharger air-to-air cooling in its "gen sets".

References

{{Reflist, colwidth=35em Heat exchangers Heat transfer Copper alloys Brazing and soldering