Staying cool by getting plastered

A paraffin-based wall coating material will prevent heat build-up in modern homes and offices, making them more pleasant places in which to live and work.

A paraffin-based wall coating material will prevent heat build-up in modern homes and offices, making them more pleasant places in which to live and work, researchers said this week.

The material, developed by the Fraunhofer Institute for Solar Energy Systems (ISE) with the help of chemicals firm BASF, consists of micro-balls of paraffin distributed within wall plaster.

The material is designed to improve temperature control in modern buildings that have thin walls made of lightweight materials. Thin walls do not absorb much thermal energy, so rooms heat up rapidly in summer. The ISE material does not insulate the walls, but instead allows heat to be stored and discharged over a 24-hour cycle.

The paraffin is encapsulated in a plexiglass material to form tiny balls with a large surface area. Each capsule is around 100 nanometres in size. The paraffin balls are then distributed within a wall plaster, which is applied as usual. When the room temperature reaches 24 degrees C, the paraffin melts, absorbing energy and storing it as latent heat.

At night as temperatures fall, the paraffin solidifies again, discharging heat that can then be released from the building through open windows or a ventilator.

‘The material is ideal for use in Europe where there are large changes in temperature between day and night,’ said Peter Schossig, a researcher at the ISE in Freiburg, Germany.

Attempts to produce an energy-saving paraffin-based material began in the 1970s after the oil crisis but were abandoned, said Schossig.

‘Drilling into walls would damage macro-encapsulated material, but our capsules are so small that this problem is avoided,’ Schossig added.

The first products containing the paraffin capsules are now commercially available in Germany.

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