Plus Minus 25: Melting curtains that could regulate room temperature

Both Koppmann and Willemsen were concerned with how climate change is affecting the global temperature. They began investigating old technologies that were used to heat and cool space, hoping to uncover a low-tech, sustainable, and affordable option for modern homes. Their research led them to PCM, and they knew immediately that this semi-forgotten material had great potential.

PCM is a substance that stores and releases thermal energy when changing phases from solid to liquid. It can be used in thermal storage systems and is already commonly used in refrigerators and in ice packs.

“Centuries ago water was used as a PCM in the basement of buildings. When the ice slowly turned to a liquid state during summer, food was kept fresh. In winter it froze and released energy to the building in form of heat,” explained Willemsen.

“This opened new applications. We found that PCM is available in a micro-encapsulated form which makes it possible to mix it with other building materials. That discovery was amazing because it enabled us to mix the material with paint and print it on fabric,” said Koppmann.

This realization led to their final Plus Minus 25, a temperature regulating curtain. The fabric of the curtain is printed with PCM that absorbs and releases heat to have a cooling effect in summer and a warming effect in winter, without using conventional devices or using any electricity.

The PCM used in the prototypes for Plus Minus 25 is active at 25 degrees Celsius. Around this temperature, the PCM starts to melt. During this melting process, it cools the air around it, and as the temperature drops, it hardens again. The melting temperature can be adjusted, and the material can be applied with different thicknesses for different climates.

Koppmann and Willemsen have been selected to be part of the antenna 2020 conference during Dutch Design Week, where 10 global graduates from across the world will share their ambitious and ground-breaking projects. Ahead of their talk, we had a chat with the two young designers.

An interview with Anna and Esmeé and Microtek is online. You can read it here including a link to their Case Study

You can also find out more on their semester project including the film they made here/below