Thermal conductivity of copper and its alloys - pros and cons

High thermal conductivity of copper and other useful characteristics have become one of the reasons for the early development of this metal by man. To this day, copper and copper alloys are used in almost all areas of our lives.

Copper plates

A little about thermal conductivity

Thermal conductivity is understood by physicists as the movement of energy in an object from the warmest tiny particles to the least heated. Due to this process the temperature of the considered subject as a whole is equalized. The magnitude of the ability to conduct heat is characterized by the coefficient of thermal conductivity. This parameter is equal to the amount of heat, which passes through a thick material 1 meter across the surface area 1 m2 for one second at a single temperature difference.

Material Coefficient of thermal conductivity, W /(m * K)

Silver	Four hundred and twenty-eight
Copper	Three hundred and ninety-four
Aluminum	Two hundred and twenty
Iron	Seventy-four
Steel	Forty-five
Lead	Thirty-five
Brick	0,77

Copper has a coefficient of thermal conductivity 394 W /(m * K) at a temperature of 20 to 100 ° C. Only silver can compete with it. And in steel and iron this figure is lower than 9 and 6 times respectively (div. table). It is worth noting, that the thermal conductivity of products, made of copper, largely depends on impurities (however, this also applies to other metals). Example, the rate of heat conduction decreases, if such substances get into copper, as:

• iron;
• arsenic;
• oxygen;
• selenium;
• aluminum;
• trumpet;
• phosphorus;
• sulfur.

Copper wire

If you add zinc to copper, then brass will come out, in which the thermal conductivity is much lower. At the same time, the addition of other substances, copper can significantly reduce the cost of finished products and give them the following characteristics, as strength and durability. Example, brass is characterized by higher technological, mechanical and antifriction properties.

Because high thermal conductivity is characterized by rapid spread of heating energy throughout the object, copper has been widely used in heat exchange systems. At the moment, radiators and tubes for refrigerators are made of it, vacuum installations and cars for fast removal of heat. Copper elements are also used in heating systems, but already for heating.

Copper heating radiator

To maintain the thermal conductivity of the metal at a high level (so, make the operation of copper devices as efficient as possible), in all heat exchange systems use forced blowing by fans. This decision is due to that, that with increasing ambient temperature, the thermal conductivity of any material is significantly reduced, after all, heat transfer is slowed down.

Aluminum and copper are better?

Aluminum has one disadvantage compared to copper: its thermal conductivity in 1,5 times less, namely 201-235 W /(m * K). However, compared to other metals, this is quite high. Aluminum is the same, as well as copper, has high anti-corrosion properties. in addition, it has the following advantages, as:

• low density (specific weight in 3 times less, than in copper);
• low cost (in 3,5 times less, than in copper).

Aluminum heating radiator

Thanks to simple calculations it turns out, that aluminum part can be cheaper than copper in 10 times, because it weighs much less and is made of cheaper material. This fact, along with high thermal conductivity allows the use of aluminum as a material for dishes and food foil for ovens. The main disadvantage of aluminum is, that it is softer, therefore, it can be used only in alloys (example, duralumin).

The rate of heat transfer to the environment plays an important role in efficient heat exchange, and this is actively facilitated by the cooling of radiators. As a result, lower thermal conductivity of aluminum (regarding copper) leveled, and the weight and cost of equipment are reduced. These important advantages allow aluminum to gradually displace copper from use in air conditioning systems.