3 ways of heat transfer, which you should know for maximum heating efficiency.
To control the temperature of the place that we are living or working in, we should know how heat behaves. By understanding the ways that heat distributes in the space around us, we can control and use it more efficiently which causes to cost reduction. There are 3 ways for heat to transfer: Conduction, Convection and Radiation.
Heat conduction happens between every two object (Material) which are in contact and have different temperatures. The heat travels from hotter object to colder one. It happens because of molecular movements. The hotter object has faster molecular movements and this kinetic energy makes colder object’s molecules to move faster. So the hotter one gets colder and the colder one gets hotter and this is how heat travels through the objects with different temperatures. Solids are more conductive than liquids and liquids are more conductive than gases. (as you may guess, because of molecular density).
Convection happens in fluids (liquids and gases). When part of a liquid gets warmer (imagine a kettle full of water on the fire), it’s density decreases and in comparison with colder part of liquid (in the same volume) it will be lighter so it goes up and changes the place with colder part of liquid. After that the colder part is near heat source and the hotter part is away of it. So the formerly cold part gets hot and rises and formerly hot part gets cold and this circulation continuous as long as heat source is on. You can easily test and observe this circulation with a drop of ink in kettle of water on fire. At first ink drop is stable at its first place but after a while it starts to circulate in the whole water because of water circulation caused by heat convection in the water.
Two aforementioned ways for heat transfer are based on a medium and material to happen, but radiation doesn’t need any material to go through. Radiation is based on electromagnetic waves and it can happen in absolute vacuum. Objects emit radiation when high energy electrons in a higher atomic level fall down to lower energy levels. So as you see it’s not depended on objects contact. The most obvious example for radiation is heat from the sun. there is nothing between us and sun to transfer heat from sun to us but because of radiation we feel its heat.
Now that we know how heat is transferred from a source to us, we can change our designs to have better efficiency for home or office heating. We will have more discussion on using these methods for warming our houses and offices efficiently, but as an interesting fact, know that 66% of our delightful feeling of temperature is cause by radiation and not by convection or conduction. Follow our next topics about efficient heating.
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