What is the principle behind passive solar heating?

The principle behind passive solar heating involves using the sun's energy to directly heat a space without the need for mechanical devices or active systems. This approach takes advantage of the design and materials of a building to absorb, store, and distribute solar energy. For example, large windows allow sunlight to enter and warm interior spaces, while materials such as thermal mass (like concrete or stone) can store the heat during the day and release it when temperatures drop at night. This method is sustainable and reduces reliance on fossil fuels for heating, making it an efficient way to maintain comfortable temperatures in buildings.

In contrast, the other options discuss various methods of utilizing solar energy or heating that involve mechanical systems or electrical processes, which do not align with the fundamental concept of passive solar heating.