Which Metals Conduct Heat Best?

Thermal conductivity measures the ability of a metal to conduct heat. This property varies across different types of metal and is important to consider in applications where high operating temperatures are common.

In pure metals thermal conductivity stays roughly the same with increases in temperature. However in alloys the thermal conductivity increases with temperature.

Which metals conduct heat best

As you can see, out of the more common metals, copper and aluminium have the highest thermal conductivity while steel and bronze have the lowest. Heat conductivity is a very important property when deciding which metal to use for a specific application. As copper is an excellent conductor of heat, it’s good for heat exchangers, heat sinks, and even saucepan bottoms. Because steel is a poor conductor of heat, it’s good for high-temperature environments like airplane engines.

Here are some important applications which require metals that conduct heat well:

Heat Exchangers

A heat exchanger is a common application where good thermal conductivity is important. Heat exchangers do their job by transferring heat to achieve heating or cooling.

Copper is a popular choice for heat exchangers in industrial facilities, air conditioning, refrigeration, hot water tanks and under-floor heating systems. Its high thermal conductivity allows heat to pass through it quickly. Copper has additional properties desirable in heat exchangers including resistance to corrosion, biofouling, stress and thermal expansion.

Aluminium can also be used in some heat exchanger applications as a more cost-effective alternative.

Heat exchangers are commonly used in the following situations:

Industrial facilities

Heat exchangers in industrial facilities include fossil and nuclear power plants, chemical plants, desalination plants and marine services.

In industrial facilities copper-nickel alloy is used to construct the heat exchanger tubing. The alloy has good corrosion resistance which protects against corrosion in saltwater environments. It also has good biofouling resistance to avoid formation of algae and sea mosses. Aluminium-brass alloy has similar properties and can be used as an alternative.

Solar thermal water systems

Solar water heaters are a cost-effective way to heat water where a copper tube is used to transfer the solar thermal energy to the water. Copper is used because of copper’s high thermal conductivity, resistance to air and water corrosion, and mechanical strength.

Gas water heaters

Gas water heat exchangers transfer the heat generated by gas fuels to water. They’re common in residential and commercial boilers. For gas water heaters, copper is the preferred material because of its high thermal conductivity and ease of fabrication.

Forced air heating and cooling

Heat pumps using air have long been used for residential and commercial heating. They work via air-to-air heat exchange through evaporator units. They can be used in wood furnaces, boilers, and stoves. Again, copper is typically used for its high thermal conductivity.

Heat sinks

Heat sinks are a type of heat exchanger that transfers heat generated by an electronic or mechanical device into a moving coolant fluid. The fluid transfers the heat away from the device, allowing it to cool to the desired temperature. Metals with high thermal conductivity are used.

Computers use heat sinks to cool central processing units or graphics processors. Heat sinks are also used in high power devices like power transistors, lasers and light emitting diodes (LEDs).

Heat sinks are designed to maximize the surface area in contact with the coolant fluid.

Aluminium alloys are the most common heat sink material. This is because aluminium costs less than copper. However copper is used where higher levels of thermal conductivity are needed. Some heat sinks use a combination aluminium fins with a copper base.

Cookware

A more household use of metal with good thermal conductivity is in cookware. When you’re heating up your food, you don’t want to wait all day. That is why copper is used in the bottoms of high-quality cookware because the metal rapidly conducts the heat and spreads it evenly across its surface.

However, if you’re on a budget you can use aluminium cookware as an alternative. It may take a little longer to heat up your food, but your wallet will thank you for it!