Theoretical and experimental analysis of atmospheric water harvesting systems for agriculture

The constant increase in World population is responsible for the huge increment in demands for essential resources as water, food and energy. These are linked together through the so called Energy-Water-Food nexus, which is a new methodology capable of explaining how the production of one of these goods is related to the others. Energy and food sectors have already found various alternatives for the production of these goods, just think to innovative methods for renewable energy sources and modern agriculture techniques characterized by lower water intensity and soil usage. On the other hand the problem of water scarcity is widely spread along the World and seems to be poor of solutions other than common ones. In this scenario atmospheric water harvesting “AWH” represents an innovative and recent method for freshwater production, characterized by high availability of resource and mature knowledge about the technology commonly used. The present work provides the analysis of an innovative device for AWH based on adsorption materials and developed by the SolarPenguins team of DENERG department of the Politecnic of Turin. The system makes use of Silica gel as sorption substrate, this interacts with air through mass and energy transfers and according to specific thermodynamic conditions it can adsorb or releases water trapped in its structure. In the analysis, the device is modelled in Matlab in order to test easily its performances in different environments without the physical need to be on place. Results in term of water productivity and energy consumption are used to carry out a feasibility study regards the integration between the device and greenhouse systems, using as experimental scenario the hydroponic greenhouse built at the Energy Centre. The aim is to demonstrate the potential of this technology as water producer able to contribute on the reduction of water scarcity problem.