Thermal mass is a material’s capacity to absorb and store heat, then release it gradually as conditions change. Dense materials such as stone, concrete, and water can provide substantial thermal mass. They can slow temperature swings, but they do not create cooling or remove heat on their own.
In cooling design, thermal mass can help keep temperatures steadier by absorbing heat during warmer periods and releasing it when the surroundings cool. Its effectiveness depends on the material, its amount and placement, and the timing of airflow or ventilation. For infrastructure that must remain usable during power interruptions, thermal mass can complement passive cooling and reduce reliance on continuously powered equipment; it is not a substitute for active refrigeration where precise temperatures are required.