Phase-change drywall boards store and release heat to save power
By Ben Coxworth
August 2, 2012
Scientists from Spain’s Universidad Politécnica de Madrid have created a new type of drywall, that they claim can reduce a building’s energy consumption by up to 40 percent. Its secret? Lots of tiny beads of paraffin.
Unlike regular drywall boards (also known as gypsum boards) which use pure plaster, paraffin microcapsules constitute almost half of the plaster mixture used in the new boards. When factors such as sunlight, electrical motors and body heat cause the temperature within a building to rise, that paraffin turns to a liquid state. In doing so, it absorbs some of the ambient heat, causing the building to cool down.
At night, when the ambient temperature drops, the paraffin solidifies, releasing the heat it stored earlier. This helps the building keep from getting too cool.
In tests of the technology, it was found that a 1.5-inch (38-mm)-thick board made from the material had five times the thermal energy capacity as a piece of regular drywall of the same thickness. A six-inch (15-cm) layer of hollow brick masonry was shown to have about the same capacity as the new drywall.
It was also noted that in an area of a building where the material was used, a temperature range of 20 to 30ºC (68 to 86ºF) could be maintained without the use of air conditioning – keep in mind, this was in Spain.
The researchers admit that the use of phase-change materials such as paraffin in drywall is not an entirely new idea, and in fact one product is already commercially available. That material is reportedly composed of just 26 percent paraffin, however, while the technology used to create the new material boosts its paraffin content to 45 percent.