Thermal Context

Heating, Ventilation, and Air Conditioning (HVAC)

Humans live in several climates where the outside temperatures would be uncomfortable or even fatal. We have designed buildings and technologies to make our homes comfortable. This heating and cooling for buildings is a major use of energy and contributor to greenhouse gas emissions.

• Natural gas is the most common fuel for heating
• Ventilation is achieved through electrical fan motors
• Air Conditioning uses the refrigeration cycle powered by electricity.

Thermal Energy Efficiency

There are several opportunities to reduce energy use and emissions.

• Produce, move, or remove heat with less energy
• Retain heat or coolth more effectively in buildings
• Deliver heat or coolth more effectively to the right places and people

This section will help us learn the basic rules that predict how heat moves and show us the way to use heat more wisely.

Heat Transfer

Whenever there is a temperature difference in space, thermal energy moves from hot to cold. This movement of thermal energy is called heat transfer or simply heat.

There are three modes of heat transfer:

• Conduction
• Convection
• Radiation