A heating & cooling system helps us cope with weather changes, live comfortably in our homes, and enjoy a good quality of life. However, these systems require a lot of energy to keep working. This article is designed to help you understand how heating and cooling works, how it impacts your home, and how you can use energy efficiency to lower your utility bills.
The heating and cooling system in your home draws in air, heats it if necessary, cools it if necessary, then distributes the conditioned air to each room of the house via ductwork. This operating style is often called a forced-air system, and it is the most common way to heat and cool homes in the US. The system operates using either natural gas, oil, electricity or a combination of these fuels to generate thermal energy heat. Then the system turns that heat into mechanical energy to move air molecules and change their state. This is why it takes a lot more energy to keep your home warm than it does to cool it.
Heating & cooling is a complex process that has many components. To keep your home at a comfortable temperature, the system needs to work in concert with convection, radiation and other factors. Let’s take a look at how this system works and why it consumes so much energy.
The main reason that heating and cooling consume so much energy is that they are machines that make heat to change the state of air. The machine can only do this efficiently if it is powered by a large source of fuel or electricity. Creating heat requires a lot of mechanical energy, so the system has to draw in a significant amount of air to keep it running. It also takes more energy to heat the air than to cool it, since the heat-generating process is more labor intensive.
If you live at a higher altitude, you may notice that your cooking instructions on packaged foods have different boiling points than those for low-altitude cooks. That’s because the atmospheric pressure decreases at higher elevations, which can affect the boiling point of a liquid.
If you want to teach your students about efficiency heating & cooling, you can start by showing them a time lapse video of water freezing and melting. You can then ask them what they observe. Explain that cooling a substance causes it to change from a liquid to a solid, while heating a substance makes its molecules move faster. This lesson can help students explore NGSS 2-PS1-4 by discussing how some of these changes can be reversed and others cannot. For example, heating butter to a high temperature causes the molecules to move more quickly and separate from each other. But, if you cool the butter again it will come back together.