New Roof System Developed by the Department Of Energy Will Save Energy Costs

The Department of Energy's Oak Ridge National Laboratory has developed new roofing techniques that could save homeowners in the neighborhood of 8% or more in summer utility bills.

Roofing has not changed much in more years that any of us can remember. That is until now with the development of active thermal mass components, reflective paint pigments and coatings, subventing and radiant barriers. These are just some of the innovative new ideas that are being tested by ORNL's Building Envelopes group headed by Bill Miller and Jan Kosny.

They have developed a prototype of a roof and attic system that reduces the temperature in an attic by close to 22 degrees F. on a typical summer afternoon and also decreases the level of heat that makes it from the attic, through the floor and then into the living space.

The main component of the system is a proprietary inorganic phase change material, which is a material that changes from solid to liquid or vise versa (changing phase). It is made up of an inorganic rehydrated salt solution with chemical additives that change the temperature at which solidification or melting occurs. They install this between layers of reflective aluminum foil, then the whole unit is installed as a thermal barrier between the roof and the attic space so that it creates separate air channels between the rafters of the roof.

It can be used with either wood or steel frames.

While this type of technology has been used in the past with a degree of success, it was not chemically stable, was not that durable and lost its capacity for the phases to change . They also had a history of going on fire.

The team is working with the countries leading manufactures of the phase change material to development non flammable organic material.

The system works like this. The phase change materials absorb heat as the temperature goes up. The inside material melts, but it still continues to absorb the heat, without an increase in its temperature. Then when the temperatures cool off at night, and the temperature around the material itself decreases, it once again becomes solid and releases the stored up heat out into the night air.