Construction Informer

Thermal mass gets rediscovered in new materials that promise significant energy-use reduction in buildings. Called PCMs, building products that incorporate these materials are already in production.

Before air conditioners, electric resistance heating and fossil-fueled furnaces people often used passive solar techniques and thermal mass to maintain comfortable temperatures within their structures. Thermal mass was especially evident in structures built from earth and stone. Beginning in the 1970s passive solar techniques and thermal mass saw a resurgence in interest from builders because of rising energy costs.

Thermal mass in particular  was rediscovered as adobe buildings, rammed earth buildings and buildings of the Earthship name, where earth is packed into rubber tires. But all of that building took a huge amount of physical and machine labor, causing them to be expensive answers to creating structures that use less energy to maintain comfortable temperatures.

New advances in materials are now giving us the option to incorporate thermal mass with much less labor. Called phase change material, or PCMs, these light weight solutions are being used to achieve up to a 98% reduction in heating and cooling costs of buildings, according to this article in NewScientist. An age-old example of a PCM is ice. The material changes form based upon temperature. The newer materials use solutions incorporating salts, or oils and fats that are derived from plants and animals.

Manufacturers are of course coming at this from many different directions but overall they are bringing some interesting products to market that can be used for retrofits, or during new construction, to reduce the energy buildings use for heating and cooling. You can get a detailed look at one example here, and also by visiting the makers of the product in the video below, which shows a PCM being installed in the building Penn State entered in the Solar Decathlon.