Top Contact Information Left Part

Unit 72,
Basepoint Business Centre,
Metcalf Way,
West sussex
RH11 7XX

Top Contact Information Right Part
Back to homepage

Latest News

Virtu utilised for clean water production and indoor air control

May 16th, 2015

WE4CCII is a Climate-KIC innovation project led by TNO in cooperation with Laborelec (GDF Suez), Naked Energy Ltd. and TU-Berlin.



WE4CCII is a Climate-KIC innovation project led by TNO in cooperation with Laborelec (GDF Suez), Naked Energy Ltd. and TU-Berlin.

It aims at the technical demonstration, business case evaluation and implementation of new value chains for production of high quality water and indoor air (humidity) control using low grade thermal waste energy from cooling water – with new technologies such as membrane distillation and water recovery from desiccant solutions.

The aim is to connect stakeholders in low grade heat production (waste, solar) with water – air networks. Reuse of low grade heat or renewable heat for high quality water production and air conditioning can substantially reduce energy consumption and CO2 emissions.

Using unexploited waste heat from cooling water can reduce electricity consumption by up to 50 per cent relative to water production using fossil fuels.


A ground-breaking innovation

The WE4CC-II project has been testing the combination of technologies for using excess heat produced by industrial processes (e.g. electricity production) or specialized solar technologies such as Virtu technology developed by Naked Energy Ltd. – that won the Venture Competition in October 2011 – in order to purify or desalinate water with the Memstill technology developed by TNO.

The cascading heat from these processes is intended to be used for heating & cooling, by using the Absorberbox technology developed by TU Berlin.

The combination of Virtu and Memstill technologies has been evaluated in the lab, while a demonstrator of the Absorberbox is running in the Berlin Botanic Gardens.

A demonstrator of the Memstill technology is now successfully evaluated at the Electrabel/Laborelec power plant in Belgium, capturing waste heat from the electricity production process and purifying surface water from a river near the site, in order to make high pressure boiler feed water.


What is the innovation?

In the WE4CC-II project an advanced membrane distillation technology (Memstill) is evaluated for the production of demineralised water and drinking water using low grade heat. Membrane distillation is a thermally driven separating process where water vapour passes through a hydrophobic membrane and high quality liquid water is retained. This process is triggered by the difference in water vapour concentration across the membrane.

By using heat to drive the process (waste heat from power plants, renewable heat from solar PVT systems, etc.), electricity consumption for high quality water production is cut and no excess heat is wasted or discharged to the environment.

Two processes have been utilised to put membrane distillation into practice:

  • Memstill: partial use of waste heat
  • Memstill with additional heat envelop (MD-HEX): full use of waste heat

WE4CC-II uses these membrane distillation technologies with the aim to commercialise the potential for waste heat / renewable heat – water cascades.

For air de-humidification, a market for future users of liquid desiccants (heat recovery, supply air drying and precise humidity control in buildings, de- humidification of greenhouses, drying of industrial goods) has to be prepared by developing a number of pilot projects, showing the technology and its specific contribution for power saving. Furthermore, industrial waste heat suppliers will be needed for the regeneration part of the desiccants.

Desiccant networks can be envisaged as a new way of energy storage and transport under use of today unexploited waste heat sources, especially as applications of air de- humidification and regeneration services will regularly not be found on the same place.


Societal Impact

Waste heat is produced by a lot of processes that use energy. The biggest contributors to waste heat are industrial processes, domestic processes and energy production that occur in the urban environment. Often, this waste heat is lost to the ambient environment, contributing to a rise in global temperature. Storage and reuse of this waste heat contribute to improving energy efficiency and reduction of CO2 emissions in the city.

This project – including the following Climate-KIC partners Netherlands Organisation for Applied Scientific Research (TNO), TU-Berlin (Technical University), Laborelec/GDF Suez, Naked Energy – is part of the Sustainable City Systems Platform and is a follow-up of the Pathfinder WE4CC.


When will it be introduced?

In 2015, the project aims to run a demonstrator at the Hotel Dolmen in Malta, where renewable heat originating from solar PVT panels (Virtu) will be used to desalinate sea water; the potential to use cascading heat from this process to heat and cool the building through the Absorberbox will also be explored. This integrated solution once demonstrated will be introduced to the market, most probably in the course of 2016.

In this framework, the project shows synergies with the following Climate- KIC projects: Energy Atlas – that maps and balances the energy sinks and sources of the city of Berlin, and CMA Pilot Metropolitan Utilities Dialogue (Berlin) – a multi-utility platform.

The product Memstill/MD-HEX modules for waste heat utilisation and the related service on technical and economic feasibility evaluation of Memstill/ MD-HEX for new customers at commercial price is planned for the end of 2015.

The product Desiccant regeneration units for waste heat utilisation, and the related service on technical and economic feasibility evaluation of desiccant regeneration for new customers at commercial price is planned for the end of 2015.

A new spin-off from TU Berlin and TNO for waste heat – water – air networks based on result of the business plan is planned for 2016.



Norbert Kuipers, Robin van Leerdam, Jolanda van Medevoort, Willy van Tongeren, Bart Verhasselt, Lieve Verelst, Marnix Vermeersch & Dominique Corbisier (2014): Techno-economic assessment of boiler feed water production by membrane distillation with reuse of thermal waste energy from cooling water, Desalination and Water Treatment.

DOI: 10.1080/19443994.2014.946722, see:

More information:

Norbert Kuipers