Conduction - First of Three Modes of Heat Transfer

In the previous blog post, we learned about heat, temperature, and heat transfer. In other to keep learning more about heat transfer as it pertains to heating systems, we will now cover three of the modes of heat transfer. We will start with the first of these three modes of heat transfer: conduction.

Conduction - Conduction has to do with heat moving through solid objects, such as heat moving from the inside wall of a copper pipe to the outside surface of the pipe, or from the inside of a house wall to the outside of the wall. Energy is being transferred between the atoms in a solid object. It is good to now that there are objects that are better in transferring heat than others. In fact, there is an indexed called thermal conductivity index that helps to categorize materials by their ability to transfer heat. 

Here are some facts to notice about heat transfer:

1) The higher the temperature, the higher the rate of heat transfer.

2) The larger the difference in temperature across materials, the higher the heat transfer.

3) The higher the rating of thermal conductivity of a material, the higher the rate of heat transfer.

However, there is one inverse relationship to consider.

- The larger the thickness of a material, the lower the rate of transfer, keeping everything else equal. 

Conduction thus can be integrated to the design of a heating system to serve the purpose of each stage of the system. For instance, designers aim to work so that the heat transfer is maximized in hydronic systems from the heating tubing to the flooring material to the air in the room. At the same time, designers aim to lower the heat transfer in a hot water storage through the use of insulation.