What is a 'thermal mass' in building design?

A 'thermal mass' in building design refers to a material that absorbs and stores heat, which plays a crucial role in temperature regulation within a building. This capability allows for the moderation of indoor temperatures by absorbing excess heat during the day and releasing it during cooler periods, such as at night.

Materials commonly regarded as thermal mass include concrete, brick, and stone, which possess high specific heat capacity, enabling them to retain heat effectively. By utilizing thermal mass, architects and engineers can create energy-efficient buildings that maintain comfortable temperatures and reduce the need for mechanical heating and cooling systems.

The other options do not accurately reflect the definition or function of thermal mass. For example, while some materials can reflect heat, this does not align with the primary function of thermal mass. Additionally, thermal mass is distinct from components directly involved with cooling systems or insulation, as it specifically refers to the heat absorption and storage properties of certain materials in building design.