One of the disadvantages of modern lightweight construction is its lack of thermal mass, which means this type of building can overheat in the summer and can鈥檛 retain heat in the winter.

Delta Membrane Systems has introduced the Delta Cool 24 鈥� a phase change material that replicates the effect of thermal mass. As the material changes from a solid to a liquid state, or vice versa, energy is released. The product uses a salt hydrate, with a melting temperature of between 22掳C and 28掳C and a crystallisation temperature of 22掳C, which provides a cooling capacity of 25-40W/m2.

There are four versions: pouches that the firm says give the best heat transfer and flexible performance for passive climate control in commercial buildings; panels that provide a dimensionally stable package for passive cooling; balls that can be used for heat storage in active systems such as solar thermal systems; and dimple sheets that can be used with floor heating systems.

Delta Membrane Systems

Regulations April 2008