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Published

5 July 2012

Process industry the model for water-saving washing-machine

A group of Swedish researchers and engineers have developed a washing-machine that cuts water usage by nearly 80 per cent. To date, two prototypes have been produced. Now the group behind the S’wash (Sustainable Domestic Washing) project want to manufacture more machines and test them in households around the world.

– We’ve tried to stretch the limits for how a washing-machine works, and in this we’ve made good progress, relates Fredrik Persson of IVL Swedish Environmental Research Institute about the newly concluded S’wash idea support project, funded by Mistra.

Since the first washing-machines came into existence about a century ago nothing new, in fact, has happened to the basic principles of washing, Persson says. One key objective of S’wash was to save water: although there is abundant clean water in Sweden it is a scarce commodity in many parts of the world. But even that is difficult, since clothes and other laundry require a certain degree of wetting.

Using the process industry as a model, however, the group have succeeded in reducing water usage to some 10 litres per wash. This is 79 per cent less than standard present-day washing-machines. Saving rinsing water from one wash enables it to be reused in the next. But this calls for a machine that can store rinsing water.

– In the prototype we’ve built, the stand for the machine has been raised by 30 centimetres to make room for water tanks. Otherwise, the machine looks the same as usual, Persson continues.

Another aim of the project was to save energy, but this proved more difficult. To enable washing to take place at lower temperatures, the project members have tried to develop more ecofriendly detergents, and this work is continuing.

Broad backing from project stakeholders

The S’wash project, on which the final report has now been issued, received SEK 6 million in idea support from Mistra in 2008. Participating industrial firms contributed the same amount. The project brought together several companies and stakeholders that had not worked together before. Along with the researchers at IVL Swedish Environmental Research Institute, the detergent producer Unilever and Akzo Nobel, which produces detergent ingredients, took part. Electrolux and Asko Appliances, the two world-leading Swedish washing-machine manufacturers, were also involved in the project. The new washing process was evaluated at Swerea IVF, while scientists at Chalmers University of Technology contributed their know-how about surface chemistry, and Imego (the Institute of Micro and Nanotechnology in Gothenburg) provided the know-how about sensor systems.

S’wash was one of the last projects in Mistra’s ‘idea support’ initiative. The group behind S’wash are now seeking other funding to continue their work and eventually launch a new washing-machine on an international market. One requirement is a better way of combating the bacterial growth that takes place in the rinsing water after a while. In addition, sensors that can detect when the rinsing water is too discoloured or dirty must be developed further.

– Our hope is to develop the prototypes and, in the long run, carry out user studies in areas of water scarcity — preferably among households in India, Australia and countries around the Mediterranean, Fredrik Persson says.

Idea support for bold environmental projects

Mistra provided idea support totalling SEK 165 million for 30 projects altogether in 2002–08. These investments made up some 10% of Mistra’s funds announced annually.

Idea support has served as a complement to Mistra’s longer-term projects, relates Mistra’s Johan Edman. Projects receiving this support, like others, were intended to foster sustainable development, but their time frame was shorter and the ambition was to support original projects that called established approaches into question.

Edman continues: ‘That’s why we’ve been able to take slightly bigger risks than in our longer-term projects. The idea support has gone to innovative research featuring bold ideas, but also great potential.’

The last idea support projects were concluded in 2011, but a couple of final reports still remain to be issued and therefore no evaluation has yet been carried out. Roughly half of the approved projects related to technological research, but projects in natural sciences, social sciences and humanities have also received idea support over the years.