Describe the critical need your solution addresses.

Watergy combines water efficiency with enhanced agricultural productivity and quality while being mainly driven by solar energy. Integrated in urban closed water- and matter cycles, it will allow a dramatic shift in resource efficiency for the supply of water, food and renewable material.

Explain your initiative in more depth and its stage of development.

From 2003-2006, two prototypes of watergy greenhouses were built in Spain and Germany. During four years, the system functions (water, energy) of the horticultural greenhouse in Spain have been approved successfully. (video at: http://www.dw-world.de/dw/article/0,,2809751,00.html). The Berlin prototype is an experimental setup for Watergy concept with greenhouses attached to buildings. The system is used as a solar collector, producing heat while using greywater for irrigation and providing condensed water for the building. (www.watergy.de).

During 2006-2008, the EU supported project “Cycler Support” did work out scenarios for integrated urban systems based on greenhouses. Synergies to solid waste / wastewater treatment as well as to concentrated solar power devices (greenhouse as closed cooling tower) are presented in the report “Overcoming Drought” http://www.emwis.net/thematicdirs/news/2008/12/eu-project-cycler-supppor...).

Since 2008, the Watergy group works on the further improvement of the Berlin Prototype, using humid air from the greenhouse during winter that is absorbed by a liquid desiccant solution to shift the air temperature in order to use for building heat supply. The diluted solution is regenerated during summer by solar energy.

How does your strategy and approach respond creatively and comprehensively to key issues?

With the end of cheap oil, the achievements of the green revolution (chemical fertilizer, pesticides, mechanisation, transport, cooling of goods) as the base of global nutrition becomes critical. Closed greenhouses, integrated in urban water- and matter circuits could provide an even higher productivity and quality while mainly usig solar energy.

Food, freshwater and renewable material can be produced based on urban residues, unconventional water sources, local minerals and CO2. The material base of a city may change from steal/concrete to biomass (e.g. bamboo, plant fibres, biogas), to sea minerals (e.g. vinyl) as well as to sand (glas).

On the base of closed atmospheres, future cities can grow into the arid and hyper arid areas. Evaporative cooling of vegetation combined with sorption based heating and cooling strategies can provide thermal comfort for buildings. On this base, the thermal mass of the construction material can be made abundant, allowing a change to radical light construction principles.