Please activate JavaScript!
Please install Adobe Flash Player, click here for download

2013|14 Annual Report Fraunhofer IGB

110 Exploiting new drinking water resources Safeguarding a drinking water supply for a growing world population is one of the most important tasks facing the gen- erations of today and tomorrow. Already, in several regions of the world, there is no reliable supply of drinking water and increasingly climate change is making the situation worse, particularly in arid and semi-arid areas. Above all in regions where there is no access to surface water or groundwater that is sustainably usable, the water contained in the ambient air as moisture can, essentially, provide a virtually inexhaust- ible source of water. The latest technology, however, has so far provided only a few systems available on the market, for example by condensation of humidity by cooling of air down to the dew point. Their disadvantage is a very high specific energy consumption and high operating and plant costs. In addition, cooling condensation only works under certain cli- matic conditions. Innovative sorptive method for the extraction of water from air moisture The approach taken by a new method developed at the Fraunhofer IGB is the extraction of water from air moisture using a combined absorption / ​desorption process. To achieve this, the absorption of air moisture by a liquid absorbent ma- terial, a highly concentrated brine, is combined with desorp- tion by means of vacuum evaporator technology (Fig. 2). The aim of a project funded by the state of Baden-Württemberg and the EU was to demonstrate, together with development partners from industry, the feasibility of an energy-self-suffi- cient, mobile facility for the decentralized extraction of water from air. From the laboratory to field trials The first step was the elaboration of the technical and scien- tific principles, the parameterization of the system and a series of preliminary trials. On the basis of these, the subcompo- nents were designed and built. After manufacture of the com- ponents, the individual systems were comprehensively tested. Following amalgamation and integration of the whole facility into containers, a series of practical trials was carried out for the purposes of evaluation of performance and demonstration of the technology as a whole. With the demonstration plant we were able, together with our development partners, to implement the technology for water extraction from air moisture on an application-oriented scale and in a quality that meets the requirements of industry. The plant consists of three containers which, alongside the absorption and desorption modules, contain all the required auxiliary units, a brine reservoir and an energy store (Figs. 1, 3 to 5). Successful start-up and test phase In a test phase lasting several weeks in autumn 2013 we were able to show that the subprocesses and the facility overall work well and that water can also be extracted from air mois- ture under real conditions. It was possible, even under what in some cases were very unfavorable environmental conditions regarding moisture content and temperature, to absorb water from the air and to separate it from the sorbent as usable drinking water. WATER EXTRACTION FROM AIR MOISTURE USING AN INNOVATIVE SORPTION METHOD Dipl.-Ing. Mike Blicker ENVIRONMENT 21 drinking water highly concentrated brine solution low- concentration brine solution absorption of water from moist air desorption of water through distillation moist air

Overview